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Sample records for acid plga microparticles

  1. In vivo biocompatibility of the PLGA microparticles in parotid gland

    PubMed Central

    Cantín, Mario; Miranda, Patricio; Suazo Galdames, Iván; Zavando, Daniela; Arenas, Patricia; Velásquez, Luis; Vilos, Cristian

    2013-01-01

    Poly(lactic-co-glycolic acid) (PLGA) microparticles are used in various disorders for the controlled or sustained release of drugs, with the management of salivary gland pathologies possible using this technology. There is no record of the response to such microparticles in the glandular parenchyma. The purpose of this study was to assess the morphological changes in the parotid gland when injected with a single dose of PLGA microparticles. We used 12 adult female Sprague Dawley rats (Rattus norvegicus) that were injected into their right parotid gland with sterile vehicle solution (G1, n=4), 0.5 mg PLGA microparticles (G2, n=4), and 0.75 mg PLGA microparticles (G3, n=4); the microparticles were dissolved in a sterile vehicle solution. The intercalar and striated ducts lumen, the thickness of the acini and the histology aspect in terms of the parenchyma organization, cell morphology of acini and duct system, the presence of polymeric residues, and inflammatory response were determined at 14 days post-injection. The administration of the compound in a single dose modified some of the morphometric parameters of parenchyma (intercalar duct lumen and thickness of the glandular acini) but did not induce tissue inflammatory response, despite the visible presence of polymer waste. This suggests that PLGA microparticles are biocompatible with the parotid tissue, making it possible to use intraglandular controlled drug administration. PMID:24228103

  2. Formulations for modulation of protein release from large-size PLGA microparticles for tissue engineering.

    PubMed

    Qodratnama, Roozbeh; Serino, Lorenzo Pio; Cox, Helen C; Qutachi, Omar; White, Lisa J

    2015-02-01

    In this study we present an approach to pre-program lysozyme release from large size (100-300 μm) poly(DL-lactic acid-co-glycolic acid) (PLGA) microparticles. This approach involved blending in-house synthesized triblock copolymers with a PLGA 85:15. In this work it is demonstrated that the lysozyme release rate and the total release are related to the mass of triblock copolymer present in polymer formulation. Two triblock copolymers (PLGA-PEG1500-PLGA and PLGA-PEG1000-PLGA) were synthesized and used in this study. In a like-for-like comparison, these two triblock copolymers appeared to have similar effects on the release of lysozyme. It was shown that blending resulted in the increase of the total lysozyme release and shortened the release period (70% release within 30 days). These results demonstrated that blending PLGA-PEG-PLGA triblock copolymer with PLGA 85:15 can be used as a method to pre-program protein release from microparticles. These microparticles with modulated protein release properties may be used to create microparticle-based tissue engineering constructs with pre-programmed release properties.

  3. Aqueous Two Phase System Assisted Self-Assembled PLGA Microparticles

    NASA Astrophysics Data System (ADS)

    Yeredla, Nitish; Kojima, Taisuke; Yang, Yi; Takayama, Shuichi; Kanapathipillai, Mathumai

    2016-06-01

    Here, we produce poly(lactide-co-glycolide) (PLGA) based microparticles with varying morphologies, and temperature responsive properties utilizing a Pluronic F127/dextran aqueous two-phase system (ATPS) assisted self-assembly. The PLGA polymer, when emulsified in Pluronic F127/dextran ATPS, forms unique microparticle structures due to ATPS guided-self assembly. Depending on the PLGA concentration, the particles either formed a core-shell or a composite microparticle structure. The microparticles facilitate the simultaneous incorporation of both hydrophobic and hydrophilic molecules, due to their amphiphilic macromolecule composition. Further, due to the lower critical solution temperature (LCST) properties of Pluronic F127, the particles exhibit temperature responsiveness. The ATPS based microparticle formation demonstrated in this study, serves as a novel platform for PLGA/polymer based tunable micro/nano particle and polymersome development. The unique properties may be useful in applications such as theranostics, synthesis of complex structure particles, bioreaction/mineralization at the two-phase interface, and bioseparations.

  4. Phagocytosis of PLGA Microparticles in Rat Peritoneal Exudate Cells: A Time-Dependent Study

    NASA Astrophysics Data System (ADS)

    Gomes, Anderson De Jesus; Nain Lunardi, Claure; Henrique Caetano, Flávio; Orive Lunardi, Laurelúcia; da Hora Machado, Antonio Eduardo

    2006-07-01

    With the purpose of enhancing the efficacy of microparticle-encapsulated therapeutic agents, in this study we evaluated the phagocytic ability of rat peritoneal exudate cells and the preferential location of poly(D,L-lactide-co-glycolic acid) (PLGA) microparticles inside these cells. The microparticles used were produced by a solvent evaporation method and were characterized by dynamic light scattering (DLS), transmission electron microscopy (TEM), and scanning electron microscopy (SEM). Size distribution analysis using DLS and SEM showed that the particles were spherical, with diameters falling between 0.5 and 1.5 [mu]m. Results from cell adhesion by SEM assay, indicated that the PLGA microparticles are not toxic to cells and do not cause any distinct damage to them as confirmed by the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide) assay. Among the large variety of cell populations found in the peritoneal exudates (neutrophils, eosinophils, monocytes, and macrophages), TEM showed that only the latter phagocytosed PLGA microparticles, in a time-dependent manner. The results obtained indicate that the microparticles studied show merits as possible carriers of drugs for intracellular delivery.

  5. Tracking the in vivo release of bioactive NRG from PLGA and PEG-PLGA microparticles in infarcted hearts.

    PubMed

    Pascual-Gil, S; Simón-Yarza, T; Garbayo, E; Prosper, F; Blanco-Prieto, M J

    2015-12-28

    The growth factor neuregulin (NRG) is one of the most promising candidates in protein therapy as potential treatment for myocardial infarction (MI). In the last few years, biomaterial based delivery systems, such as polymeric microparticles (MPs) made of poly(lactic co glycolic acid) and polyethylene glycol (PLGA and PEG-PLGA MPs), have improved the efficacy of protein therapy in preclinical studies. However, no cardiac treatment based on MPs has yet been commercialized since this is a relatively new field and total characterization of polymeric MPs remains mandatory before they reach the clinical arena. Therefore, the objective of this study was to characterize the in vivo release, bioactivity and biodegradation of PLGA and PEG-PLGA MPs loaded with biotinylated NRG in a rat model of MI. The effect of PEGylation in the clearance of the particles from the cardiac tissue was also evaluated. Interestingly, MPs were detected in the cardiac tissue for up to 12 weeks after administration. In vivo release analysis showed that bNRG was released in a controlled manner throughout the twelve week study. Moreover, the biological cardiomyocyte receptor (ErbB4) for NRG was detected in its activated form only in those animals treated with bNRG loaded MPs. On the other hand, the PEGylation strategy was effective in diminishing phagocytosis of these MPs compared to noncoated MPs in the long term (12 weeks after injection). Taking all this together, we report new evidence in favor of the use of polymeric PLGA and PEG-PLGA MPs as delivery systems for treating MI, which could be soon included in clinical trials.

  6. Bioerodable PLGA-Based Microparticles for Producing Sustained-Release Drug Formulations and Strategies for Improving Drug Loading

    PubMed Central

    Han, Felicity Y.; Thurecht, Kristofer J.; Whittaker, Andrew K.; Smith, Maree T.

    2016-01-01

    Poly(lactic-co-glycolic acid) (PLGA) is the most widely used biomaterial for microencapsulation and prolonged delivery of therapeutic drugs, proteins and antigens. PLGA has excellent biodegradability and biocompatibility and is generally recognized as safe by international regulatory agencies including the United States Food and Drug Administration and the European Medicines Agency. The physicochemical properties of PLGA may be varied systematically by changing the ratio of lactic acid to glycolic acid. This in turn alters the release rate of microencapsulated therapeutic molecules from PLGA microparticle formulations. The obstacles hindering more widespread use of PLGA for producing sustained-release formulations for clinical use include low drug loading, particularly of hydrophilic small molecules, high initial burst release and/or poor formulation stability. In this review, we address strategies aimed at overcoming these challenges. These include use of low-temperature double-emulsion methods to increase drug-loading by producing PLGA particles with a small volume for the inner water phase and a suitable pH of the external phase. Newer strategies for producing PLGA particles with high drug loading and the desired sustained-release profiles include fabrication of multi-layered microparticles, nanoparticles-in-microparticles, use of hydrogel templates, as well as coaxial electrospray, microfluidics, and supercritical carbon dioxide methods. Another recent strategy with promise for producing particles with well-controlled and reproducible sustained-release profiles involves complexation of PLGA with additives such as polyethylene glycol, poly(ortho esters), chitosan, alginate, caffeic acid, hyaluronic acid, and silicon dioxide. PMID:27445821

  7. Rifapentine-loaded PLGA microparticles for tuberculosis inhaled therapy: Preparation and in vitro aerosol characterization.

    PubMed

    Parumasivam, Thaigarajan; Leung, Sharon S Y; Quan, Diana Huynh; Triccas, Jamie A; Britton, Warwick J; Chan, Hak-Kim

    2016-06-10

    Inhaled delivery of drugs incorporated into poly (lactic-co-glycolic acid) (PLGA) microparticles allows a sustained lung concentration and encourages phagocytosis by alveolar macrophages that harboring Mycobacterium tuberculosis. However, limited data are available on the effects of physicochemical properties of PLGA, including the monomer ratio (lactide:glycide) and molecular weight (MW) on the aerosol performance, macrophage uptake, and toxicity profile. The present study aims to address this knowledge gap, using PLGAs with monomer ratios of 50:50, 75:25 and 85:15, MW ranged 24 - 240kDa and an anti-tuberculosis (TB) drug, rifapentine. The PLGA-rifapentine powders were produced through a solution spray drying technique. The particles were spherical with a smooth surface and a volume median diameter around 2μm (span ~2). When the powders were dispersed using an Osmohaler(®) at 100L/min for 2.4s, the fine particle fraction (FPFtotal, wt.% particles in aerosol <5μm relative to the total recovered drug mass) was ranged between 52 and 57%, with no significant difference between the formulations. This result suggests that the monomer ratio and MW are not crucial parameters for the aerosol performance of PLGA. The phagocytosis analysis was performed using Thp-1 monocyte-derived macrophages. The highest rate of uptake was observed in PLGA 85:15 followed by 75:25 and 50:50 with about 90%, 80% and 70%, respectively phagocytosis over 4h of exposure. Furthermore, the cytotoxicity analysis on Thp-1 and human lung adenocarcinoma epithelial cells demonstrated that PLGA concentration up to 1.5mg/mL, regardless of the monomer composition and MW, were non-toxic. In conclusion, the monomer ratio and MW are not crucial in determining the aerosol performance and cytotoxicity profile of PLGA however, the particles with high lactide composition have a superior tendency for macrophage uptake.

  8. Preclinical Development and In Vivo Efficacy of Ceftiofur-PLGA Microparticles

    PubMed Central

    Vilos, Cristian; Velasquez, Luis A.; Rodas, Paula I.; Zepeda, Katherine; Bong, Soung-Jae; Herrera, Natalia; Cantin, Mario; Simon, Felipe; Constandil, Luis

    2015-01-01

    Drug delivery systems based on polymeric microparticles represent an interesting field of development for the treatment of several infectious diseases for humans and animals. In this work, we developed PLGA microparticles loaded with ceftiofur (PLGA-cef), a third- generation cephalosporin that is used exclusively used in animals. PLGA-cef was prepared by the double emulsion w/o/w method, and exhibited a diameter in the range of 1.5–2.2 μm, and a negative ζ potential in the range of -35 to -55 mV. The loading yield of PLGA-cef was ~7% and encapsulation efficiency was approximately 40%. The pharmacokinetic study demonstrated a sustained release profile of ceftiofur for 20 days. PLGA-cef administrated in a single dose was more effective than ceftiofur non-encapsulated in rats challenged with S. Typhimurium. The in vivo toxicological evaluation showed that PLGA-cef did not affect the blood biochemical, hematological and hemostasis parameters. Overall, the PLGA-cef showed slow in vivo release profile, high antibacterial efficacy, and low toxicity. The results obtained supports the safe application of PLGA-cef as sustained release platform in the veterinary industry. PMID:25915043

  9. Preclinical Development and In Vivo Efficacy of Ceftiofur-PLGA Microparticles.

    PubMed

    Vilos, Cristian; Velasquez, Luis A; Rodas, Paula I; Zepeda, Katherine; Bong, Soung-Jae; Herrera, Natalia; Cantin, Mario; Simon, Felipe; Constandil, Luis

    2015-01-01

    Drug delivery systems based on polymeric microparticles represent an interesting field of development for the treatment of several infectious diseases for humans and animals. In this work, we developed PLGA microparticles loaded with ceftiofur (PLGA-cef), a third- generation cephalosporin that is used exclusively used in animals. PLGA-cef was prepared by the double emulsion w/o/w method, and exhibited a diameter in the range of 1.5-2.2 μm, and a negative ζ potential in the range of -35 to -55 mV. The loading yield of PLGA-cef was ~7% and encapsulation efficiency was approximately 40%. The pharmacokinetic study demonstrated a sustained release profile of ceftiofur for 20 days. PLGA-cef administrated in a single dose was more effective than ceftiofur non-encapsulated in rats challenged with S. Typhimurium. The in vivo toxicological evaluation showed that PLGA-cef did not affect the blood biochemical, hematological and hemostasis parameters. Overall, the PLGA-cef showed slow in vivo release profile, high antibacterial efficacy, and low toxicity. The results obtained supports the safe application of PLGA-cef as sustained release platform in the veterinary industry.

  10. Bioactive PLGA-curcumin microparticle-embedded chitosan scaffold: in vitro and in vivo evaluation.

    PubMed

    Amirthalingam, Muthukumar; Kasinathan, Narayanan; Amuthan, Arul; Mutalik, Srinivas; Sreenivasa Reddy, M; Nayanabhirama, Udupa

    2017-03-01

    Wound healing is a complex process affected by several factors. In the present work, novel biocompatible PLGA-curcumin microparticle-embedded chitosan scaffold was fabricated for wound-healing application. Process variables involved in the preparation of microparticles were optimized using design of experiment. Scanning electron microscopy (SEM) confirmed the porous nature of scaffold with embedded microparticles. A maximum release of 14% of the encapsulated curcumin was observed at 12th hour. Modified tube dilution method showed that scaffold significantly (p < 0.05) reduced multiplication of Staphylococcus aureus. More than 50% of the excised wound in rats healed in 4 days with an epithilization period of 18 days.

  11. Disulfiram-loaded porous PLGA microparticle for inhibiting the proliferation and migration of non-small-cell lung cancer

    PubMed Central

    Wang, Chenhui; Yang, Jiebing; Han, Haobo; Chen, Jiawen; Wang, Yudi; Li, Quanshun; Wang, Yanbo

    2017-01-01

    In this study, poly(lactic-co-glycolic acid) (PLGA) was used as a carrier to construct disulfiram-loaded porous microparticle through the emulsion solvent evaporation method, using ammonium bicarbonate as a porogen. The microparticle possessed highly porous surface, suitable aerodynamic diameter for inhalation (8.31±1.33 µm), favorable drug loading (4.09%±0.11%), and sustained release profile. The antiproliferation effect of release supernatant was detected through 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay using non-small-cell lung cancer A549 as a model, with only 13.3% of cell viability observed for the release supernatant at 7 days. The antiproliferation mechanism was elucidated to be associated with the enhanced induction of cell apoptosis and cell cycle arrest at S phase through flow cytometry and Western blotting analysis. Finally, wound healing and transwell migration assay showed that they could efficiently inhibit the cell migration. These results demonstrated that disulfiram-loaded porous PLGA microparticle could achieve favorable antitumor efficiency, implying the potential of treating non-small-cell lung cancer in a pulmonary administration. PMID:28182125

  12. The visualisation of vitreous using surface modified poly(lactic-co-glycolic acid) microparticles.

    PubMed

    Chau, David Y S; Tint, Naing L; Collighan, Russell J; Griffin, Martin; Dua, Harminder S; Shakesheff, Kevin M; Rose, Felicity R A J

    2010-05-01

    AIMS To demonstrate the potential use of in vitro poly(lactic-co-glycolic acid) (PLGA) microparticles in comparison with triamcinolone suspension to aid visualisation of vitreous during anterior and posterior vitrectomy. METHODS PLGA microparticles (diameter 10-60 microm) were fabricated using single and/or double emulsion technique(s) and used untreated or following the surface adsorption of a protein (transglutaminase). Particle size, shape, morphology and surface topography were assessed using scanning electron microscopy (SEM) and compared with a standard triamcinolone suspension. The efficacy of these microparticles to enhance visualisation of vitreous against the triamcinolone suspension was assessed using an in vitro set-up exploiting porcine vitreous. RESULTS Unmodified PLGA microparticles failed to adequately adhere to porcine vitreous and were readily washed out by irrigation. In contrast, modified transglutaminase-coated PLGA microparticles demonstrated a significant improvement in adhesiveness and were comparable to a triamcinolone suspension in their ability to enhance the visualisation of vitreous. This adhesive behaviour also demonstrated selectivity by not binding to the corneal endothelium. CONCLUSION The use of transglutaminase-modified biodegradable PLGA microparticles represents a novel method of visualising vitreous and aiding vitrectomy. This method may provide a distinct alternative for the visualisation of vitreous whilst eliminating the pharmacological effects of triamcinolone acetonide suspension.

  13. Silicon microfluidic flow focusing devices for the production of size-controlled PLGA based drug loaded microparticles.

    PubMed

    Keohane, Kieran; Brennan, Des; Galvin, Paul; Griffin, Brendan T

    2014-06-05

    The increasing realisation of the impact of size and surface properties on the bio-distribution of drug loaded colloidal particles has driven the application of micro fabrication technologies for the precise engineering of drug loaded microparticles. This paper demonstrates an alternative approach for producing size controlled drug loaded PLGA based microparticles using silicon Microfluidic Flow Focusing Devices (MFFDs). Based on the precise geometry and dimensions of the flow focusing channel, microparticle size was successfully optimised by modifying the polymer type, disperse phase (Qd) flow rate, and continuous phase (Qc) flow rate. The microparticles produced ranged in sizes from 5 to 50 μm and were highly monodisperse (coefficient of variation <5%). A comparison of Ciclosporin (CsA) loaded PLGA microparticles produced by MFFDs vs conventional production techniques was also performed. MFFDs produced microparticles with a narrower size distribution profile, relative to the conventional approaches. In-vitro release kinetics of CsA was found to be influenced by the production technique, with the MFFD approach demonstrating the slowest rate of release over 7 days (4.99 ± 0.26%). Finally, MFFDs were utilised to produce pegylated microparticles using the block co-polymer, PEG-PLGA. In contrast to the smooth microparticles produced using PLGA, PEG-PLGA microparticles displayed a highly porous surface morphology and rapid CsA release, with 85 ± 6.68% CsA released after 24h. The findings from this study demonstrate the utility of silicon MFFDs for the precise control of size and surface morphology of PLGA based microparticles with potential drug delivery applications.

  14. Enhanced encapsulation and bioavailability of breviscapine in PLGA microparticles by nanocrystal and water-soluble polymer template techniques.

    PubMed

    Wang, Hong; Zhang, Guangxing; Ma, Xueqin; Liu, Yanhua; Feng, Jun; Park, Kinam; Wang, Wenping

    2017-03-02

    Poly (lactide-co-glycolide) (PLGA) microparticles are widely used for controlled drug delivery. Emulsion methods have been commonly used for preparation of PLGA microparticles, but they usually result in low loading capacity, especially for drugs with poor solubility in organic solvents. In the present study, the nanocrystal technology and a water-soluble polymer template method were used to fabricate nanocrystal-loaded microparticles with improved drug loading and encapsulation efficiency for prolonged delivery of breviscapine. Breviscapine nanocrystals were prepared using a precipitation-ultrasonication method and further loaded into PLGA microparticles by casting in a mold from a water-soluble polymer. The obtained disc-like particles were then characterized and compared with the spherical particles prepared by an emulsion-solvent evaporation method. X-ray powder diffraction (XRPD) and confocal laser scanning microscopy (CLSM) analysis confirmed a highly-dispersed state of breviscapine inside the microparticles. The drug form, loading percentage and fabrication techniques significantly affected the loading capacity and efficiency of breviscapine in PLGA microparticles, and their release performance as well. Drug loading was increased from 2.4 % up to 15.3 % when both nanocrystal and template methods were applied, and encapsulation efficiency increased from 48.5 % to 91.9 %. But loading efficiency was reduced as the drug loading was increased. All microparticles showed an initial burst release, and then a slow release period of 28 days followed by an erosion-accelerated release phase, which provides a sustained delivery of breviscapine over a month. A relatively stable serum drug level for more than 30 days was observed after intramuscular injection of microparticles in rats. Therefore, PLGA microparticles loaded with nanocrystals of poorly soluble drugs provided a promising approach for long-term therapeutic products characterized with preferable in vitro and in

  15. Targeted oral delivery of BmpB vaccine using porous PLGA microparticles coated with M cell homing peptide-coupled chitosan.

    PubMed

    Jiang, Tao; Singh, Bijay; Li, Hui-Shan; Kim, You-Kyoung; Kang, Sang-Kee; Nah, Jae-Woon; Choi, Yun-Jaie; Cho, Chong-Su

    2014-02-01

    M cells, the key players of the mucosal immunity induction, are one of the intestinal barriers for the efficient delivery of vaccines to mucosal immune tissues. To overcome the barrier, we have developed an efficient oral vaccine carrier that constitutes poly (lactic-co-glycolic acid) (PLGA) microparticle coated with M cell targeting peptide. In this study, a membrane protein B of Brachyspira hyodysenteriae (BmpB) as a model vaccine against swine dysentery was loaded into porous PLGA microparticles (MPs). The PLGA MPs were further coated with the water-soluble chitosan (WSC) conjugated with M cell homing peptide (CKS9) to prepare BmpB-CKS9-WSC-PLGA MPs. Oral immunization of BmpB vaccine with CKS9-WSC-PLGA MPs in mice showed elevated secretory IgA responses in the mucosal tissues and systemic IgG antibody responses, providing a complete immune response. Specifically, the immunization with these MPs demonstrated to induce both Th1- and Th2-type responses based on elevated IgG1 and IgG2a titers. The elevated immune responses were attributed to the enhanced M cell targeting and transcytosis ability of CKS9-WSC-PLGA MPs to Peyer's patch regions. The high binding affinity of CKS9-WSC-PLGA MPs with the M cells to enter into the Peyer's patch regions of mouse small intestine was investigated by closed ileal loop assay and it was further confirmed by confocal laser scanning microscopy. These results suggest that the M cell targeting approach used in this study is a promising tool for targeted oral vaccine delivery.

  16. Modulating the Rigidity and Mineralization of Collagen Gels Using Poly(Lactic-Co-Glycolic Acid) Microparticles

    PubMed Central

    DeVolder, Ross J.; Kim, Il Won; Kim, Eun-Suk

    2012-01-01

    Extensive efforts have been made to prepare osteoconductive collagen gels for the regeneration of normal bone and the pathological examination of diseased bone; however, collagen gels are often plagued by limited controllability of their rigidity and mineral deposition. This study reports a simple but efficient strategy that tunes the mechanical properties of, and apatite formation in, collagen gels by incorporating hydrolyzable poly(lactic-co-glycolic acid) (PLGA) microparticles within the gels. The PLGA microparticles are associated with the collagen fibrils and increased both the gel's elasticity and rigidity while minimally influencing its permeability. As compared with pure collagen gels, the PLGA microparticle-filled collagen gels, termed PLGA-Col hydrogels, significantly enhanced the deposition of apatite-like minerals within the gels when incubated in simulated body fluid or encapsulated with mesenchymal stem cells (MSCs) undergoing osteogenic differentiation. Finally, PLGA-Col hydrogels mineralized by differentiated MSCs led to an enhanced formation of bone-like tissues within the hydrogels. Overall, the PLGA-Col hydrogel system developed in this study will serve to improve the quality of osteoconductive matrices for both fundamental and clinical studies that are relevant to bone repair, regeneration, and pathogenesis. PMID:22480235

  17. Control of Alginate Core Size in Alginate-Poly (Lactic-Co-Glycolic) Acid Microparticles

    NASA Astrophysics Data System (ADS)

    Lio, Daniel; Yeo, David; Xu, Chenjie

    2016-01-01

    Core-shell alginate-poly (lactic-co-glycolic) acid (PLGA) microparticles are potential candidates to improve hydrophilic drug loading while facilitating controlled release. This report studies the influence of the alginate core size on the drug release profile of alginate-PLGA microparticles and its size. Microparticles are synthesized through double-emulsion fabrication via a concurrent ionotropic gelation and solvent extraction. The size of alginate core ranges from approximately 10, 50, to 100 μm when the emulsification method at the first step is homogenization, vortexing, or magnetic stirring, respectively. The second step emulsification for all three conditions is performed with magnetic stirring. Interestingly, although the alginate core has different sizes, alginate-PLGA microparticle diameter does not change. However, drug release profiles are dramatically different for microparticles comprising different-sized alginate cores. Specifically, taking calcein as a model drug, microparticles containing the smallest alginate core (10 μm) show the slowest release over a period of 26 days with burst release less than 1 %.

  18. Characterization of porous PLGA/PLA microparticles as a scaffold for three dimensional growth of breast cancer cells.

    PubMed

    Sahoo, Sanjeeb K; Panda, Amulya K; Labhasetwar, Vinod

    2005-01-01

    We have designed and evaluated biodegradable porous polymeric microparticles as a scaffold for cell growth. The hypothesis was that microparticles with optimized composition and properties would have better cell adhesion and hence cell growth into a tissue-like structure. Solvent-evaporation method was modified using sucrose as an additive to form large porous microparticles of poly(D,L-lactic-co-glycolic) (PLGA) and polylactide (PLA) polymers. Microparticles containing hydrophilic polymers (poly(vinyl alcohol) and chitosan) incorporated in their internal matrix structure were also formulated. Different formulations of microparticles were evaluated for physical properties, cell adhesion, and cell growth in culture. PLA microparticles containing poly(vinyl alcohol) (PVA) in the matrix structure (PLA-PVA) and treated with serum prior to cell seeding demonstrated better cell adhesion and cell growth than other formulations of microparticles. Cells were seen to grow into clumps, engulfing microparticles completely with time, and forming a 3-D tissue-like structure. Cell density of 1.5 x 10(6) cells per mg of microparticles was achieved in 9 days of culture, which was a 7-fold increase from the initial seeding cell density. The mechanism of better cell growth on PLA-PVA microparticles appears to be due to the PVA associated with the internal matrix structure of microparticles. These microparticles demonstrated better wetting in culture and also cell adhesion. In addition to tissue engineering applications, microparticles with cancer cells grown into a tissue-like structure in vitro can be potentially used as a model system for preclinical evaluation of the cytotoxic effect of anticancer agents.

  19. Design and characterization of core-shell mPEG-PLGA composite microparticles for development of cell-scaffold constructs.

    PubMed

    Wen, Yanhong; Gallego, Monica Ramos; Nielsen, Lene Feldskov; Jorgensen, Lene; Møller, Eva Horn; Nielsen, Hanne Mørck

    2013-09-01

    Appropriate scaffolds capable of providing suitable biological and structural guidance are of great importance to generate cell-scaffold constructs for cell-based tissue engineering. The aim of the present study was to develop composite microparticles with a structure to provide functionality as a combined drug delivery/scaffold system. Composite microparticles were produced by incorporating either alginate/dermatan sulfate (Alg/DS) or alginate/chitosan/dermatan sulfate (Alg/CS/DS) particles in mPEG-PLGA microparticles using coaxial ultrasonic atomization. The encapsulation and distribution of Alg/DS or Alg/CS/DS particles in the mPEG-PLGA microparticles were significantly dependent on the operating conditions, including the flow rate ratio (Qout/Qin) and the viscosity of the polymer solutions (Vout, Vin) between the outer and the inner feeding channels. The core-shell composite microparticles containing the Alg/DS particles or the Alg/CS/DS particles displayed 40% and 65% DS release in 10 days, respectively, as compared to the DS directly loaded microparticles showing 90% DS release during the same time interval. The release profiles of DS correlate with the cell proliferation of fibroblasts, i.e. more sustainable cell growth was induced by the DS released from the core-shell composite microparticles comprising Alg/CS/DS particles. After seeding fibroblasts onto the composite microparticles, excellent cell adhesion was observed, and a successful assembly of the cell-scaffold constructs was induced within 7 days. Therefore, the present study demonstrates a novel strategy for fabrication of core-shell composite microparticles comprising additional particulate drug carriers in the core, which provides controlled delivery of DS and favorable cell biocompatibility; an approach to potentially achieve cell-based tissue regeneration.

  20. Biocompatibility and enhanced osteogenic differentiation of human mesenchymal stem cells in response to surface engineered poly(D,L-lactic-co-glycolic acid) microparticles.

    PubMed

    Rogers, Catherine M; Deehan, David J; Knuth, Callie A; Rose, Felicity R A J; Shakesheff, Kevin M; Oldershaw, Rachel A

    2014-11-01

    Tissue engineering strategies can be applied to enhancing osseous integration of soft tissue grafts during ligament reconstruction. Ligament rupture results in a hemarthrosis, an acute intra-articular bleed rich in osteogenic human mesenchymal stem cells (hMSCs). With the aim of identifying an appropriate biomaterial with which to combine hemarthrosis fluid-derived hMSCs (HF-hMSCs) for therapeutic application, this work has investigated the biocompatibility of microparticles manufactured from two forms of poly(D,L-lactic-co-glycolic acid) (PLGA), one synthesized with equal monomeric ratios of lactic acid to glycolic acid (PLGA 50:50) and the other with a higher proportion of lactic acid (PLGA 85:15) which confers a longer biodegradation time. The surfaces of both types of microparticles were functionalized by plasma polymerization with allylamine to increase hydrophilicity and promote cell attachment. HF-hMSCs attached to and spread along the surface of both forms of PLGA microparticle. The osteogenic response of HF-hMSCs was enhanced when cultured with PLGA compared with control cultures differentiated on tissue culture plastic and this was independent of the type of polymer used. We have demonstrated that surface engineered PLGA microparticles are an appropriate biomaterial for combining with HF-hMSCs and the selection of PLGA is relevant only when considering the biodegradation time for each biomedical application.

  1. Evaluation of different buffers on plasmid DNA encapsulation into PLGA microparticles.

    PubMed

    Tse, Man Tsuey; Blatchford, Chris; Oya Alpar, H

    2009-03-31

    Double emulsion solvent evaporation is a widely used method to prepare poly(dl-lactide-co-glycolide) (PLGA) microparticles encapsulating plasmid DNA. There are inherent problems associated with preparing plasmid DNA in this form, in particular the DNA is liable to degrade during manufacture and the resulting powder has low encapsulation efficiencies. This study compares the use of two buffers, 0.1M NaHCO(3) and 0.07M Na(2)HPO(4) and the effect these have on the encapsulation efficiency and other critical parameters associated with these encapsulated DNA materials. Both buffers preserved the conformation of the original plasmid DNA during the homogenization process, but those made with 0.07M Na(2)HPO(4) had higher encapsulation efficiencies, as well as smaller diameters, compared with those made with 0.1M NaHCO(3) (encapsulation efficiencies of 40.72-45.65%, and mean volume diameters of 2.96-4.45microm). Buffers with a range of pH from 5 to 12 were investigated, and it was demonstrated that pH 9 was the point at which the highest amount of supercoiled DNA was balanced with the highest encapsulation efficiency. To simulate in vitro release, it was shown that microparticles made with 0.07M Na(2)HPO(4) had lower DNA release rates than those made with 0.1M NaHCO(3). These results demonstrate that the use of different buffers can aid in retaining the conformation of plasmid DNA, and can also modulate the amount of DNA encapsulated and the release profiles of microparticles.

  2. Localised controlled release of simvastatin from porous chitosan-gelatin scaffolds engrafted with simvastatin loaded PLGA-microparticles for bone tissue engineering application.

    PubMed

    Gentile, Piergiorgio; Nandagiri, Vijay Kumar; Daly, Jacqueline; Chiono, Valeria; Mattu, Clara; Tonda-Turo, Chiara; Ciardelli, Gianluca; Ramtoola, Zebunnissa

    2016-02-01

    Localised controlled release of simvastatin from porous freeze-dried chitosan-gelatin (CH-G) scaffolds was investigated by incorporating simvastatin loaded poly-(dl-lactide-co-glycolide) acid (PLGA) microparticles (MSIMs) into the scaffolds. MSIMs at 10% w/w simvastatin loading were prepared using a single emulsion-solvent evaporation method. The MSIM optimal amount to be incorporated into the scaffolds was selected by analysing the effect of embedding increasing amounts of blank PLGA microparticles (BL-MPs) on the scaffold physical properties and on the in vitro cell viability using a clonal human osteoblastic cell line (hFOB). Increasing the BL-MP content from 0% to 33.3% w/w showed a significant decrease in swelling degree (from 1245±56% to 570±35%). Scaffold pore size and distribution changed significantly as a function of BL-MP loading. Compressive modulus of scaffolds increased with increasing BL-MP amount up to 16.6% w/w (23.0±1.0kPa). No significant difference in cell viability was observed with increasing BL-MP loading. Based on these results, a content of 16.6% w/w MSIM particles was incorporated successfully in CH-G scaffolds, showing a controlled localised release of simvastatin able to influence the hFOB cell proliferation and the osteoblastic differentiation after 11 days.

  3. Controlling the morphology of electrospray-generated PLGA microparticles for drug delivery.

    PubMed

    Almería, Begoña; Deng, Weiwei; Fahmy, Tarek M; Gomez, Alessandro

    2010-03-01

    We developed a well-controlled method to generate PLGA microparticles of different morphologies using the electrospray drying route. By judiciously selecting polymer molecular weight, concentration, and solution flow rate, we can control the order in which polymer entanglements and Coulomb fission occur in the droplets and their relative importance, and subsequently govern the morphology of the resulting polymer particles. We show that spherical, monodisperse particles are generated when sufficiently strong polymer entanglements set in the evaporating droplets before they undergo any Coulomb fission. On the other hand, tailed and elongated particles are obtained if the Coulomb fission occurs first and if the droplets/particles are sufficiently evaporated to freeze in their irregular shape. Strictly spherical particles are unachievable for polymer solutions below a critical concentration, because the onset of Coulomb fission always sets in prior to the development of a sufficiently entangled polymer network. An extension of a simple model, originally used to determine the onset of electrospinning of polymer solutions, adequately predicts when non-spherical particles are produced. We conclude by demonstrating the scale-up of this approach to the synthesis of polymer particles using a compact, microfabricated, multiplexed electrospray system, which would make it suitable for practical applications.

  4. The biocompatibility of calcium phosphate cements containing alendronate-loaded PLGA microparticles in vitro

    PubMed Central

    Li, Yu-Hua; Wang, Zhen-Dong; Wang, Wei; Ding, Chang-Wei; Zhang, Hao-Xuan

    2015-01-01

    The composite of poly-lactic-co-glycolic acid (PLGA) and calcium phosphate cements (CPC) are currently widely used in bone tissue engineering. However, the properties and biocompatibility of the alendronate-loaded PLGA/CPC (APC) porous scaffolds have not been characterized. APC scaffolds were prepared by a solid/oil/water emulsion solvent evaporation method. The morphology, porosity, and mechanical strength of the scaffolds were characterized. Bone marrow mesenchymal stem cells (BMSCs) from rabbit were cultured, expanded and seeded on the scaffolds, and the cell morphology, adhesion, proliferation, cell cycle and osteogenic differentiation of BMSCs were determined. The results showed that the APC scaffolds had a porosity of 67.43 ± 4.2% and pore size of 213 ± 95 µm. The compressive strength for APC was 5.79 ± 1.21 MPa, which was close to human cancellous bone. The scanning electron microscopy, cell counting kit-8 assay, flow cytometry and ALP activity revealed that the APC scaffolds had osteogenic potential on the BMSCs in vitro and exhibited excellent biocompatibility with engineered bone tissue. APC scaffolds exhibited excellent biocompatibility and osteogenesis potential and can potentially be used for bone tissue engineering. PMID:25877763

  5. Development of a Sustainable Release System for a Ranibizumab Biosimilar Using Poly(lactic-co-glycolic acid) Biodegradable Polymer-Based Microparticles as a Platform.

    PubMed

    Tanetsugu, Yusuke; Tagami, Tatsuaki; Terukina, Takayuki; Ogawa, Takaya; Ohta, Masato; Ozeki, Tetsuya

    2017-01-01

    Ranibizumab is a humanized monoclonal antibody fragment against vascular endothelial growth factor (VEGF)-A and is widely used to treat age-related macular degeneration (AMD) caused by angiogenesis. Ranibizumab has a short half-life in the eye due to its low molecular weight and susceptibility to proteolysis. Monthly intravitreal injection of a large amount of ranibizumab formulation is a burden for both patients and medical staff. We therefore sought to develop a sustainable release system for treating the eye with ranibizumab using a drug carrier. A ranibizumab biosimilar (RB) was incorporated into microparticles of poly(lactic-co-glycolic acid) (PLGA) biodegradable polymer. Ranibizumab was sustainably released from PLGA microparticles (80+% after 3 weeks). Assay of tube formation by endothelial cells indicated that RB released from PLGA microparticles inhibited VEGF-induced tube formation and this tendency was confirmed by a cell proliferation assay. These results indicate that RB-loaded PLGA microparticles are useful for sustainable RB release and suggest the utility of intraocular sustainable release systems for delivering RB site-specifically to AMD patients.

  6. Improved small molecule drug release from in situ forming poly(lactic-co-glycolic acid) scaffolds incorporating poly(β-amino ester) and hydroxyapatite microparticles.

    PubMed

    Fisher, Paul D; Palomino, Pablo; Milbrandt, Todd A; Hilt, J Zach; Puleo, David A

    2014-01-01

    In situ forming implants are an attractive choice for controlled drug release into a fixed location. Currently, rapidly solidifying solvent exchange systems suffer from a high initial burst, and sustained release behavior is tied to polymer precipitation and degradation rate. The present studies investigated addition of hydroxyapatite (HA) and drug-loaded poly(β-amino ester) (PBAE) microparticles to in situ forming poly(lactic-co-glycolic acid) (PLGA)-based systems to prolong release and reduce burst. PBAEs were synthesized, imbibed with simvastatin (osteogenic) or clodronate (anti-resorptive), and then ground into microparticles. Microparticles were mixed with or without HA into a PLGA solution, and the mixture was injected into buffer, leading to precipitation and creating solid scaffolds with embedded HA and PBAE microparticles. Simvastatin release was prolonged through 30 days, and burst release was reduced from 81 to 39% when loaded into PBAE microparticles. Clodronate burst was reduced from 49 to 32% after addition of HA filler, but release kinetics were unaffected after loading into PBAE microparticles. Scaffold dry mass remained unchanged through day 15, with a pronounced increase in degradation rate after day 30, while wet scaffolds experienced a mass increase through day 25 due to swelling. Porosity and pore size changed throughout degradation, likely due to a combination of swelling and degradation. The system offers improved release kinetics, multiple release profiles, and rapid solidification compared to traditional in situ forming implants.

  7. Improved small molecule drug release from in situ forming poly(lactic-co-glycolic acid) scaffolds incorporating poly(β-amino ester) and hydroxyapatite microparticles

    PubMed Central

    Fisher, Paul D.; Palomino, Pablo; Milbrandt, Todd A.; Hilt, J. Zach; Puleo, David A.

    2014-01-01

    In situ forming implants are an attractive choice for controlled drug release into a fixed location. Currently, rapidly solidifying solvent exchange systems suffer from a high initial burst, and sustained release behavior is tied to polymer precipitation and degradation rate. The present studies investigated addition of hydroxyapatite (HA) and drug-loaded poly(β-amino ester) (PBAE) microparticles to in situ forming poly(lactic-co-glycolic acid) (PLGA)–based systems to prolong release and reduce burst. PBAEs were synthesized, imbibed with simvastatin (osteogenic) or clodronate (anti-resorptive), and then ground into microparticles. Microparticles were mixed with or without HA into a PLGA solution, and the mixture was injected into buffer, leading to precipitation and creating solid scaffolds with embedded HA and PBAE microparticles. Simvastatin release was prolonged through 30 days, and burst release was reduced from 81% to 39% when loaded into PBAE microparticles. Clodronate burst was reduced from 49% to 32% after addition of HA filler, but release kinetics were unaffected after loading into PBAE microparticles. Scaffold dry mass remained unchanged through day 15, with a pronounced increase in degradation rate after day 30, while wet scaffolds experienced a mass increase through day 25 due to swelling. Porosity and pore size changed throughout degradation, likely due to a combination of swelling and degradation. The system offers improved release kinetics, multiple release profiles, and rapid solidification compared to traditional in situ forming implants. PMID:24903524

  8. Reversible Hydrophobic Ion-Paring Complex Strategy to Minimize Acylation of Octreotide during Long-Term Delivery from PLGA Microparticles

    PubMed Central

    Vaishya, Ravi D.; Mandal, Abhirup; Gokulgandhi, Mitan; Patel, Sulabh; Mitra, Ashim K.

    2015-01-01

    Acylation of peptide has been reported for a number of peptides and proteins during release from polymers comprising of lactide and glycolide. We hypothesize that reversible hydrophobic ion-pairing (HIP) complex may minimize octreotide acylation during release. Sodium dodecyl sulfate (SDS), dextran sulfate A (DSA, Mw 9–20kDa) and dextran sulfate B (DSB, Mw 36–50kDa) were selected as ion-pairing agents to prepare reversible HIP complex with octreotide. Complexation efficiency was optimized with respect to the mole ratio of ion-pairing agent to octreotide to achieve 100% complexation of octreotide. Dissociation studies suggested that DSA-octreotide and DSB-octreotide complexes dissociate completely at physiological pH in presence of counter ions unlike SDS-octreotide complex. DSA-octreotide and DSB-octreotide complex encapsulated PLGA microparticles (DSAMPs and DSBMPs) were prepared using the S/O/W emulsion method. Entrapment efficiencies for DSAMPs and DSBMPs were 74.7±8.4% and 81.7±6.3%, respectively. In vitro release of octreotide was performed by suspending MPs in gel. A large fraction of peptide was released in chemically intact form and <7% was acylated from DSAMPs and DSBMPs in gel over 55 days. Therefore, HIP complexation could be a viable strategy to minimize acylation of peptides and proteins during extended release from lactide and glycolide based polymers. PMID:25940041

  9. Enhanced Osteoblast Functions on Nanophase Titania in Poly-lactic-co-glycolic Acid (PLGA) Composites

    DTIC Science & Technology

    2005-01-01

    Poly - lactic -co-glycolic Acid (PLGA) Composites Huinan Liu’, Elliott B. Slamovich’ and Thomas J. Webster’ 2 1School of Materials Engineering, 501...collagen matrix. For this purpose, poly - lactic -co- glycolic acid (PLGA) was dissolved in chloroform and nanometer grain size titania was dispersed by...gelatin, fibrin or collagen [4-6]), synthetic bioresorbable polymers (e.g., polylactic acid , polyglycolic acid and poly - lactic -co-glycolic acid [7-9

  10. Thermally processed polymeric microparticles for year-long delivery of dexamethasone.

    PubMed

    Goodfriend, Amy C; Welch, Tré R; Nguyen, Kytai T; Johnson, Romaine F; Sebastian, Vinod; Reddy, Surendranath Veeram; Forbess, Joseph; Nugent, Alan

    2016-01-01

    Dexamethasone-releasing poly(lactic-co-glycolic acid) (PLGA) microparticles were formulated using a solvent displacement technique with the addition of distillation aiming to increase drug delivery lifetime. Two PLGA copolymer ratios (50:50 and 75:25) were used to determine the influence of lactic acid and glycolic acid ratio on microparticle characteristics. The addition of distillation significantly slows the release of dexamethasone compared to traditional solvent removal via evaporation while still maintaining a therapeutic dosage. Microparticles formulated with PLGA 50:50 controllably release dexamethasone up to one year and 75:25 release up to two years in-vitro. The ratio of lactic acid to glycolic acid plays a significant role in microparticle stability, drug loading efficiency, and thermal properties. In all, this formulation technique offers new prospects for inflammation suppression in pediatric vascular and airway diseases.

  11. Exploring polyvinylpyrrolidone in the engineering of large porous PLGA microparticles via single emulsion method with tunable sustained release in the lung: In vitro and in vivo characterization.

    PubMed

    Ni, Rui; Muenster, Uwe; Zhao, Jing; Zhang, Lan; Becker-Pelster, Eva-Maria; Rosenbruch, Martin; Mao, Shirui

    2017-03-10

    Sustained pulmonary drug delivery is regarded as an effective strategy for local treatment of chronic lung diseases. Despite of the progress made so far, there remains a need for respirable drug loaded porous microparticles, where porosity of the microparticles can be readily engineered during the preparation process, with tunable sustained drug release upon lung deposition. In this work, polyvinyl pyrrolidone (PVP) was used as a novel porogen to engineer PLGA-based large porous particles (LPPs) using single emulsion method, with fine tuning of the porosity, sustained drug release both in vitro and in vivo. Using cinaciguat as the model drug, influence of PVP content and PLGA type on the properties of the LPPs was characterized, including geometric particle size, drug encapsulation efficiency, tap density, theoretical and experimental aerodynamic particle size, specific surface area, morphology, and in vitro drug release. Solid state of cinaciguat in the LPPs was studied based on DSC and X-ray analysis. LPPs retention in the rat lung was carried out using bronchoalveolar lavage fluid method. Raw 264.7 macrophage cells were used for LPPs uptake study. Pharmacodynamic study was performed in mini-pigs in a well-established model of pulmonary arterial hypertension (thromboxane challenge). It was demonstrated that porosity of the LPPs is tunable via porogen content variation. Cinaciguat can be released from the LPP in a controlled manner for over 168h. Significant reduction of macrophage phagocytosis was presented for LPPs. Furthermore, LPPs was found to have extended retention time (~36h) in the rat lung and accordingly, sustained pharmacodynamics effect was achieved in mini-pig model. Taken together, our results demonstrated that this simple PLGA based LPPs engineering using single emulsion method with PVP as porogen may find extensive application for the pulmonary delivery of hydrophobic drugs to realize tunable sustained effect with good safety profile.

  12. Particulate Systems Based on Poly(Lactic-co-Glycolic)Acid (pLGA) for Immunotherapy of Cancer.

    PubMed

    Rahimian, Sima; Fransen, Marieke F; Kleinovink, Jan Willem; Amidi, Maryam; Ossendorp, Ferry; Hennink, Wim E

    2015-01-01

    Immunotherapy of cancer is a promising therapeutic approach which aims to eliminate malignancies by inducing or enhancing an immune response against the tumor. Immunotherapy, however, faces several challenges such as local immunosuppression in the tumor area leading to immunological tolerance. To overcome these challenges, particulate formulations such as nano- and microparticles containing immunotherapeutics have been developed to increase therapeutic efficacy and reduce toxicity of immunotherapy. Particulate formulations based on biodegradable aliphatic polyesters such as poly(lactic-co-glycolic acid) (pLGA) have been extensively used with promising results. In this review, we addressed the potential of pLGA-based particulate formulations for immunotherapy of cancer. The discussion was focused on cancer vaccines and delivery of immunomodulatory antibodies. Features and drawbacks of pLGA systems were discussed together with several examples of recently developed therapeutic cancer vaccines and antibody-loaded particulate systems. Various strategies to overcome the drawbacks and optimize the formulations were given. In conclusion, pLGA-based particulate systems are attractive carriers for development of clinically acceptable formulations in immunotherapy of cancer.

  13. Hyaluronic Acid/PLGA Core/Shell Fiber Matrices Loaded with EGCG Beneficial to Diabetic Wound Healing.

    PubMed

    Shin, Yong Cheol; Shin, Dong-Myeong; Lee, Eun Ji; Lee, Jong Ho; Kim, Ji Eun; Song, Sung Hwa; Hwang, Dae-Youn; Lee, Jun Jae; Kim, Bongju; Lim, Dohyung; Hyon, Suong-Hyu; Lim, Young-Jun; Han, Dong-Wook

    2016-12-01

    During the last few decades, considerable research on diabetic wound healing strategies has been performed, but complete diabetic wound healing remains an unsolved problem, which constitutes an enormous biomedical burden. Herein, hyaluronic acid (HA)/poly(lactic-co-glycolic acid, PLGA) core/shell fiber matrices loaded with epigallocatechin-3-O-gallate (EGCG) (HA/PLGA-E) are fabricated by coaxial electrospinning. HA/PLGA-E core/shell fiber matrices are composed of randomly-oriented sub-micrometer fibers and have a 3D porous network structure. EGCG is uniformly dispersed in the shell and sustainedly released from the matrices in a stepwise manner by controlled diffusion and PLGA degradation over four weeks. EGCG does not adversely affect the thermomechanical properties of HA/PLGA-E matrices. The number of human dermal fibroblasts attached on HA/PLGA-E matrices is appreciably higher than that on HA/PLGA counterparts, while their proliferation is steadily retained on HA/PLGA-E matrices. The wound healing activity of HA/PLGA-E matrices is evaluated in streptozotocin-induced diabetic rats. After two weeks of surgical treatment, the wound areas are significantly reduced by the coverage with HA/PLGA-E matrices resulting from enhanced re-epithelialization/neovascularization and increased collagen deposition, compared with no treatment or HA/PLGA. In conclusion, the HA/PLGA-E matrices can be potentially exploited to craft strategies for the acceleration of diabetic wound healing and skin regeneration.

  14. Controlled Release of Nor-β-lapachone by PLGA Microparticles: A Strategy for Improving Cytotoxicity against Prostate Cancer Cells.

    PubMed

    Costa, Marcilia P; Feitosa, Anderson C S; Oliveira, Fátima C E; Cavalcanti, Bruno C; da Silva, Eufrânio N; Dias, Gleiston G; Sales, Francisco A M; Sousa, Bruno L; Barroso-Neto, Ito L; Pessoa, Cláudia; Caetano, Ewerton W S; Di Fiore, Stefano; Fischer, Rainer; Ladeira, Luiz O; Freire, Valder N

    2016-07-02

    Prostate cancer is one of the most common malignant tumors in males and it has become a major worldwide public health problem. This study characterizes the encapsulation of Nor-β-lapachone (NβL) in poly(d,l-lactide-co-glycolide) (PLGA) microcapsules and evaluates the cytotoxicity of the resulting drug-loaded system against metastatic prostate cancer cells. The microcapsules presented appropriate morphological features and the presence of drug molecules in the microcapsules was confirmed by different methods. Spherical microcapsules with a size range of 1.03 ± 0.46 μm were produced with an encapsulation efficiency of approximately 19%. Classical molecular dynamics calculations provided an estimate of the typical adsorption energies of NβL on PLGA. Finally, the cytotoxic activity of NβL against PC3M human prostate cancer cells was demonstrated to be significantly enhanced when delivered by PLGA microcapsules in comparison with the free drug.

  15. Comparative studies on exenatide-loaded poly (D,L-lactic-co-glycolic acid) microparticles prepared by a novel ultra-fine particle processing system and spray drying.

    PubMed

    Zhu, Chune; Huang, Ying; Zhang, Xiaoying; Mei, Liling; Pan, Xin; Li, Ge; Wu, Chuanbin

    2015-08-01

    The purpose of this study was to compare the properties of exenatide-loaded poly (D,L-lactic-co-glycolic acid) microparticles (Ex-PLGA-MPs) prepared by a novel ultra-fine particle processing system (UPPS) and spray drying. UPPS is a proprietary technology developed by our group based on the disk rotation principle. Characteristics of the MPs including morphology, particle size distribution, drug content, encapsulation efficiency and in vitro release were comparatively studied. Cytotoxicity of the MPs was examined on A549 cells and the pharmacodynamics was investigated in vivo in type 2 diabetes Sprague-Dawley (SD) rats. Ex-PLGA-MPs prepared by UPPS showed larger particle size, denser surface, greater encapsulation efficiency, less initial burst release, and stable sustained release for more than one month in vitro as compared with the spray drying MPs. Meanwhile, the UPPS MPs effectively controlled the body growth rate and blood glucose in diabetes rats for at least three weeks after a single injection, while the spray drying MPs showed effective control period of about two weeks. UPPS technology was demonstrated to manufacture Ex-PLGA-MPs as a potential sustained release protein/polypeptide delivery system, which is an alternative method for the most commonly used spray drying. This comparative research provides a new guidance for microparticle preparation technology.

  16. Facile fabrication of siloxane @ poly (methylacrylic acid) core-shell microparticles with different functional groups

    NASA Astrophysics Data System (ADS)

    Zhao, Zheng-Bai; Tai, Li; Zhang, Da-Ming; Jiang, Yong

    2017-02-01

    Siloxane @ poly (methylacrylic acid) core-shell microparticles with functional groups were prepared by a facile hydrolysis-condensation method in this work. Three different silane coupling agents 3-methacryloxypropyltrimethoxysilane (MPS), 3-triethoxysilylpropylamine (APTES), and 3-glycidoxypropyltrimethoxysilane (GPTMS) were added along with tetraethoxysilane (TEOS) into the polymethylacrylic acid (PMAA) microparticle ethanol dispersion to form the Si@PMAA core-shell microparticles with different functional groups. The core-shell structure and the surface special functional groups of the resulting microparticles were measured by transmission electron microscopy and FTIR. The sizes of these core-shell microparticles were about 350-400 nm. The corresponding preparation conditions and mechanism were discussed in detail. This hydrolysis-condensation method also could be used to functionalize other microparticles which contain active groups on the surface. Meanwhile, the Si@PMAA core-shell microparticles with carbon-carbon double bonds and amino groups have further been applied to prepare hydrophobic coatings.

  17. Effects of lactic acid and glycolic acid on human osteoblasts: a way to understand PLGA involvement in PLGA/calcium phosphate composite failure.

    PubMed

    Meyer, Florent; Wardale, John; Best, Serena; Cameron, Ruth; Rushton, Neil; Brooks, Roger

    2012-06-01

    The use of degradable composite materials in orthopedics remains a field of intense research due to their ability to support new bone formation and degrade in a controlled manner, broadening their use for orthopedic applications. Poly (lactide-co-glycolide) acid (PLGA), a degradable biopolymer, is now a popular material for different orthopedic applications and is proposed for use in tissue engineering scaffolds either alone or combined with bioactive ceramics. Interference screws composed of calcium phosphates and PLGA are readily available in the market. However, some reports highlight problems of screw migration or aseptic cyst formation following screw degradation. In order to understand these phenomena and to help to improve implant formulation, we have evaluated the effects of PLGA degradation products: lactic acid and glycolic acid on human osteoblasts in vitro. Cell proliferation, differentiation, and matrix mineralization, important for bone healing were studied. It was found that the toxicity of polymer degradation products under buffering conditions was limited to high concentrations. However, non-toxic concentrations led to a decrease in cell proliferation, rapid cell differentiation, and mineralization failure. Calcium, whilst stimulating cell proliferation was not able to overcome the negative effects of high concentrations of lactic and glycolic acids on osteoblasts. These effects help to explain recently reported clinical failures of calcium phosphate/PLGA composites, but further in vitro analyses are needed to mimic the dynamic situation which occurs in the body by, for example, culture of osteoblasts with materials that have been pre-degraded to different extents and thus be able to relate these findings to the degradation studies that have been performed previously.

  18. Interaction between dimethyldioctadecylammonium bromide-modified PLGA microspheres and hyaluronic acid

    NASA Astrophysics Data System (ADS)

    Mulia, Kamarza; Devi, Krisanti, Elsa

    2017-02-01

    In application of intravitreal injection, an extended drug delivery system is desired so that the frequency of injection to treat diabetic retinopathy may be reduced. Poly(lactic-co-glycolic acid) polymer (PLGA) was used to encapsulate a model drug in the form of microspheres. The zeta potential of dimethyldioctadecylammonium bromide (DDAB)-modified PLGA microspheres in water was proportional to the DDAB concentration used in the preparation step, up to +57.8 mV. The scanning electron microscope pictures and the zeta potential data (SEM) confirmed that the surface of the PLGA has been modified by the cationic surfactant and that electrostatic interaction between the positively charged microspheres and the negatively charged vitreous were present.

  19. Development and characterization of hyaluronic acid decorated PLGA nanoparticles for delivery of 5-fluorouracil.

    PubMed

    Yadav, Awesh K; Agarwal, Abhinav; Rai, Gopal; Mishra, Pradeep; Jain, Sanyog; Mishra, Anil K; Agrawal, Himanshu; Agrawal, Govind P

    2010-11-01

    The present investigation was aimed to develop and explore the prospective of engineered PLGA nanoparticles as vehicles for targeted delivery of 5-fluorouracil (5-FU). Nanoparticles of 5-FU-loaded hyaluronic acid-poly(ethylene glycol)-poly(lactide-co-glycolide) (HA-PEG-PLGA-FU) copolymer were prepared and characterized by FTIR, NMR, transmission electron microscopy, particle size analysis, DSC, and X-ray diffractometer measurement studies. The nanoparticulate formulation was evaluated for in vitro release, hemolytic toxicity, and hematological toxicity. Cytotoxicity studies were performed on Ehrlich ascites tumor (EAT) cell lines using MTT cell proliferation assay. Biodistribution studies of 99m Tc labeled formulation were conducted on EAT-bearing mice. The in vivo tumor inhibition study was also performed after i.v. administration of HA-PEG-PLGA-FU nanoparticles. The HA conjugated formulation was found to be less hemolytic but more cytotoxic as compared to free drug. The hematological data suggested that HA-PEG-PLGA-FU formulation was less immunogenic compared to plain drug. The tissue distribution studies displayed that HA-PEG-PLGA-FU were able to deliver a higher concentration of 5-FU in the tumor mass. In addition, the HA-PEG-PLGA-FU nanoparticles reduced tumor volume significantly in comparison with 5-FU. Thus, it was concluded that the conjugation of HA imparts targetability to the formulation, and enhanced permeation and retention effect ruled out its access to the non-tumor tissues, at the same time favored selective entry in tumors, thereby reducing the side-effects both in vitro and in vivo.

  20. Glycolic acid-catalyzed deamidation of asparagine residues in degrading PLGA matrices: a computational study.

    PubMed

    Manabe, Noriyoshi; Kirikoshi, Ryota; Takahashi, Ohgi

    2015-03-31

    Poly(lactic-co-glycolic acid) (PLGA) is a strong candidate for being a drug carrier in drug delivery systems because of its biocompatibility and biodegradability. However, in degrading PLGA matrices, the encapsulated peptide and protein drugs can undergo various degradation reactions, including deamidation at asparagine (Asn) residues to give a succinimide species, which may affect their potency and/or safety. Here, we show computationally that glycolic acid (GA) in its undissociated form, which can exist in high concentration in degrading PLGA matrices, can catalyze the succinimide formation from Asn residues by acting as a proton-transfer mediator. A two-step mechanism was studied by quantum-chemical calculations using Ace-Asn-Nme (Ace = acetyl, Nme = NHCH3) as a model compound. The first step is cyclization (intramolecular addition) to form a tetrahedral intermediate, and the second step is elimination of ammonia from the intermediate. Both steps involve an extensive bond reorganization mediated by a GA molecule, and the first step was predicted to be rate-determining. The present findings are expected to be useful in the design of more effective and safe PLGA devices.

  1. Spontaneous arrangement of a tumor targeting hyaluronic acid shell on irinotecan loaded PLGA nanoparticles.

    PubMed

    Giarra, Simona; Serri, Carla; Russo, Luisa; Zeppetelli, Stefania; De Rosa, Giuseppe; Borzacchiello, Assunta; Biondi, Marco; Ambrosio, Luigi; Mayol, Laura

    2016-04-20

    The arrangement of tumor targeting hyaluronic acid (HA) moieties on irinotecan (IRIN)-loaded poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NPs) has been directed by means of a gradient of lipophilicity between the oil and water phases of the emulsion used to produce the NPs. PLGA constitutes the NP bulk while HA is superficially exposed, with amphiphilic poloxamers acting as a bridge between PLGA and HA. Differential scanning calorimetry, zeta potential analyses and ELISA tests were employed to support the hypothesis of polymer assembly in NP formulations. The presence of flexible HA chains on NP surface enhances NP size stability over time due to an increased electrostatic repulsion between NPs and a higher degree of hydration of the device surface. IRIN in vitro release kinetics can be sustained up to 7-13 days. In vitro biologic studies indicated that HA-containing NPs were more toxic than bare PLGA NPs against CD44-overexpressing breast carcinoma cells (HS578T), therefore indicating their ability to target CD44 receptor.

  2. Novel Simvastatin-Loaded Nanoparticles Based on Cholic Acid-Core Star-Shaped PLGA for Breast Cancer Treatment.

    PubMed

    Wu, Yanping; Wang, Zhongyuan; Liu, Gan; Zeng, Xiaowei; Wang, Xusheng; Gao, Yongfeng; Jiang, Lijuan; Shi, Xiaojun; Tao, Wei; Huang, Laiqiang; Mei, Lin

    2015-07-01

    A novel nanocarrier system of cholic acid (CA) core, star-shaped polymer consisting of poly(D,L-lactide-co-glycolide) (PLGA) was developed for sustained and controlled delivery of simvastatin for chemotherapy of breast adenocarcinoma. The star-shaped polymer CA-PLGA with three branch arms was synthesized successfully through the core-first approach. The simvastatin-loaded star-shaped CA-PLGA nanoparticles were prepared through a modified nanoprecipitation method. The data showed that the fluorescence star-shaped CA-PLGA nanoparticles could be internalized into MDA-MB-231 and MDA-MB-468 human breast cancer cells. The simvastatin-loaded star-shaped CA-PLGA nanoparticles achieved significantly higher level of cytotoxicity than pristine simvastatin and simvastatin-loaded linear PLGA nanoparticles. Moreover, the expression of the cell cycle protein cyclin D1 was dramatically inhibited by simvastatin in both cells, with simvastatin-loaded star-shaped CA-PLGA nanoparticles having the greatest effect. MDA-MB-231 xenograft tumor model on BALB/c nude mice showed that simvastatin-loaded star-shaped CA-PLGA nanoformulations could effectively inhibit the growth of tumor over a longer period of time than pristine simvastatin and simvastatin-loaded linear PLGA nanoformulations at the same dose. In agreement with these, the nuclear expression of proliferation marker Ki-67 in simvastatin-loaded star-shaped CA-PLGA nanoparticles group was reduced to a most extent among four groups through tumor frozen section immunohistochemistry. In conclusion, the star-shaped CA-PLGA polymers could serve as a novel polymeric nanocarrier for breast cancer chemotherapy.

  3. Nanoscaled buffering zone of charged (PLGA)n-b-bPEI micelles in acidic microclimate for potential protein delivery application

    PubMed Central

    Kang, Han Chang; Lee, Ji Eun; Bae, You Han

    2012-01-01

    Poly(lactide-co-glycolide) (PLGA) has most often been employed for the controlled release of protein formulations because of its safety profile with non-toxic degradation products. Nevertheless, such formulations have been plagued by a local acidic microenvironment and protein-polymer interactions, which result in chemical and physical denaturation of loaded proteins and often unfavorable release profiles. This study investigated the pH change of inner PLGA microsphere (MS) using charged (PLGA)n-b-branched polyethyleneimine (bPEI) micelles. The designed micelles can be transformed into either micelle or reverse micelle (RM) depending on the solvent and RM can form microspheres. In addition, (PLGA)n-b-bPEI can be modified into (PLGA)n-b-(carboxylated bPEI) via carboxylation of the primary amines. Cationic micelle (CM) or anionic micelle (AM) were complexed with counter-charged proteins leading to nanosized particles (approximately 100 nm). In the micelle/protein complexes, the micelles mostly maintained their proton buffering capacity, and consequently, prevented or delayed the typical decrease in pH caused by degradation of PLGA in aqueous solution. Reconstitutable micelle/protein complexes allowed for increased and fine-tuned protein loading (~20 wt% when using CM1 (CM prepared from PLGA36kDa-b-bPEI25kDa)/insulin complexes) in PLGA MS. In CM2 (CM prepared from (PLGA36kDa)2-b-bPEI25kDa)/insulin (4 of weight ratio (WR) of micelle to protein; WR4)-loaded PLGA MS, CM2 strongly prevented the micellar nanoenvironmental pH (pH 6.6 within 5 days and then approximately pH 8.5) to be acidified in PLGA MS for 9 weeks, unlike CM2-free PLGA MS. In conclusion, our findings propose that the proton buffering capacity and protein loading in PLGA MS can be tuned by controlling the complexation ratios of micelles and proteins, polymeric architectures of (PLGA)n-b-bPEI copolymers and WR of micelle/protein complexes and PLGA (or RM). PMID:22405902

  4. Bone Regeneration from PLGA Micro-Nanoparticles

    PubMed Central

    Ortega-Oller, Inmaculada; Padial-Molina, Miguel; Galindo-Moreno, Pablo; O'Valle, Francisco; Jódar-Reyes, Ana Belén; Peula-García, Jose Manuel

    2015-01-01

    Poly-lactic-co-glycolic acid (PLGA) is one of the most widely used synthetic polymers for development of delivery systems for drugs and therapeutic biomolecules and as component of tissue engineering applications. Its properties and versatility allow it to be a reference polymer in manufacturing of nano- and microparticles to encapsulate and deliver a wide variety of hydrophobic and hydrophilic molecules. It additionally facilitates and extends its use to encapsulate biomolecules such as proteins or nucleic acids that can be released in a controlled way. This review focuses on the use of nano/microparticles of PLGA as a delivery system of one of the most commonly used growth factors in bone tissue engineering, the bone morphogenetic protein 2 (BMP2). Thus, all the needed requirements to reach a controlled delivery of BMP2 using PLGA particles as a main component have been examined. The problems and solutions for the adequate development of this system with a great potential in cell differentiation and proliferation processes under a bone regenerative point of view are discussed. PMID:26509156

  5. Controlled release behaviour of protein-loaded microparticles prepared via coaxial or emulsion electrospray.

    PubMed

    Wang, Ying; Yang, Xiaoping; Liu, Wentao; Zhang, Feng; Cai, Qing; Deng, Xuliang

    2013-01-01

    Biodegradable poly (lactic-co-glycolic acid) (PLGA) microparticles are an effective way to achieve sustained drug release. In this study, we investigated a sustained release model of PLGA microparticles with incorporated protein via either emulsion or coaxial electrospray techniques. PLGA (75:25) was used as the carrier, and bovine serum albumin as a model protein. Coaxial electrospray resulted in a type of core-shell structure with mean diameters of 2.41 ± 0.60 µm and a centralised protein distribution within the core. Emulsion electrospray formed bigger microparticles with mean diameters of 22.75 ± 8.05 µm and a heterogeneous protein distribution throughout the microparticles. The coaxial electrospray microparticles presented a much slighter burst release than the emulsion electrospray microparticles. Loading efficiency was significantly higher (p < 0.05) in the coaxial group than emulsion group. This indicated that both emulsion and coaxial electrospray could produce protein-loaded microparticles with sustained release behaviour, but the former revealed a superior approach for drug delivery.

  6. Controlled release behaviour of protein-loaded microparticles prepared via coaxial or emulsion electrospray

    PubMed Central

    Wang, Ying; Yang, Xiaoping; Liu, Wentao; Zhang, Feng; Cai, Qing; Deng, Xuliang

    2013-01-01

    Biodegradable poly (lactic-co-glycolic acid) (PLGA) microparticles are an effective way to achieve sustained drug release. In this study, we investigated a sustained release model of PLGA microparticles with incorporated protein via either emulsion or coaxial electrospray techniques. PLGA (75:25) was used as the carrier, and bovine serum albumin as a model protein. Coaxial electrospray resulted in a type of core–shell structure with mean diameters of 2.41 ± 0.60 µm and a centralised protein distribution within the core. Emulsion electrospray formed bigger microparticles with mean diameters of 22.75 ± 8.05 µm and a heterogeneous protein distribution throughout the microparticles. The coaxial electrospray microparticles presented a much slighter burst release than the emulsion electrospray microparticles. Loading efficiency was significantly higher (p < 0.05) in the coaxial group than emulsion group. This indicated that both emulsion and coaxial electrospray could produce protein-loaded microparticles with sustained release behaviour, but the former revealed a superior approach for drug delivery. PMID:23346923

  7. Stable cationic microparticles for enhanced model antigen delivery to dendritic cells.

    PubMed

    Wischke, Christian; Borchert, Hans-Hubert; Zimmermann, Julian; Siebenbrodt, Ingo; Lorenzen, Dirk R

    2006-09-12

    The objectives of this work were (i) to prepare physically stable cationic microparticles and (ii) to study the impact of the surface properties on microparticle phagocytosis and the phenotype of dendritic cells (DC). Protein loaded biodegradable microparticles from poly(lactic-co-glycolic acid) [PLGA] were produced in a micromixer-based w/o/w solvent evaporation procedure. Anionic particles were obtained by using polyvinyl alcohol (PVA) as stabilizing agent; for cationic surfaces cetyltrimethylammonium bromide (CTAB) and chitosan/PVA or DEAE-dextran/PVA blends were evaluated. In phagocytosis studies human monocytes and monocyte-derived DC were incubated with microparticles and analysed by flow cytometry. While CTAB modified microparticles lost their positive charge and aggregated due to CTAB desorption from the particle surface, the modification with chitosan and DEAE-dextran resulted in stable microparticles without cell toxicity. Due to a very low endotoxin content, phagocytosis of anionic and cationic microparticles did not induce an upregulation of maturation-associated surface markers on DC. DEAE-dextran modified microparticles showed an enhanced model protein delivery into phagocytic cells. Overall, PLGA microparticles are suitable vehicles for protein delivery to DC, which might be used for DC-based cell therapies.

  8. Freeze dried chitosan/ poly-(glutamic acid) microparticles for intestinal delivery of lansoprazole.

    PubMed

    Singh, Mangla Nand; Yadav, Hemant K S; Ram, Munshi; Shivakumar, H G

    2012-01-01

    Lansoprazole sodium is a proton pump inhibitor used in treating gastroesophageal reflux disease (GERD). It is highly acid-labile and presents many formulation challenges. Therefore, this drug needs to be protected from the harsh environment in the stomach. In order to achieve this, a pH-sensitive microparticle system composed of chitosan and γ- poly-(glutamic acid) was prepared and loaded with Lansoprazole. The prepared microparticles were not stable in gastric pH. To overcome this problem microparticles were freez-dried and filled in an enteric-coated capsule. Upon oral administration, the enteric-coated capsule remained intact in the acidic environment of the stomach, but dissolved rapidly in the distal segment of the GIT. Consequently, all the microparticles loaded in the capsule were brought into the intestine, thus enhancing the intestinal absorption of drug. Drug encapsulation efficiency of formulation F3 was found to be 82.82 % and in vitro release of prepared formulation F3 was found to be 94% after 8 h of dissolution in 7.4 pH phosphate buffer. FTIR and DSC studies showed no interaction between the drug and polymer. The formulation showed good swelling property. SEM photographs showed that microparticles are spherical and lies in size range of 300-400 μm. From the above, it can be concluded that the prepared chitosan/ γ-poly-(glutamic acid) microparticles can be used as carriers for the intestinal delivery of acid liable drugs such as lansoprazole.

  9. Drug release behavior of poly (lactic-glycolic acid) grafting from sodium alginate (ALG-g-PLGA) prepared by direct polycondensation.

    PubMed

    Shi, Gang; Ding, Yuanyuan; Zhang, Xin; Wu, Luyan; He, Fei; Ni, Caihua

    2015-01-01

    Hydrophobically modified sodium alginate, poly (lactic-glycolic acid) grafting from sodium alginate (ALG-g-PLGA), was successfully synthesized through direct one-step polymerization of sodium alginate, glycolic acid, and lactic acid. ALG-g-PLGA self-assembled to colloidal nanoparticles and subsequently hydrogel microspheres were obtained by crosslinking ALG-g-PLGA nanoparticles in the solution of calcium chloride. The modified hydrogel microspheres could be used as the drug delivery vehicles for a hydrophobic ibuprofen. Compared with sodium alginate, ALG-g-PLGA demonstrated an improved drug loading rate, encapsulation efficiency, and prolonged release speed. The products, as novel and highly promising biomaterials, have potential applications.

  10. Inhalable oridonin-loaded poly(lactic-co-glycolic)acid large porous microparticles for in situ treatment of primary non-small cell lung cancer.

    PubMed

    Zhu, Lifei; Li, Miao; Liu, Xiaoyan; Du, Lina; Jin, Yiguang

    2017-01-01

    Non-small cell lung cancer (NSCLC) accounts for about 85% of all lung cancers. Traditional chemotherapy for this disease leads to serious side effects. Here we prepared an inhalable oridonin-loaded poly(lactic-co-glycolic)acid (PLGA) large porous microparticle (LPMP) for in situ treatment of NSCLC with the emulsion/solvent evaporation/freeze-drying method. The LPMPs were smooth spheres with many internal pores. Despite a geometric diameter of ~10 µm, the aerodynamic diameter of the spheres was only 2.72 µm, leading to highly efficient lung deposition. In vitro studies showed that most of oridonin was released after 1 h, whereas the alveolar macrophage uptake of LPMPs occurred after 8 h, so that most of oridonin would enter the surroundings without undergoing phagocytosis. Rat primary NSCLC models were built and administered with saline, oridonin powder, gemcitabine, and oridonin-loaded LPMPs via airway, respectively. The LPMPs showed strong anticancer effects. Oridonin showed strong angiogenesis inhibition and apoptosis. Relevant mechanisms are thought to include oridonin-induced mitochondrial dysfunction accompanied by low mitochondrial membrane potentials, downregulation of BCL-2 expressions, upregulation of expressions of BAX, caspase-3 and caspase-9. The oridonin-loaded PLGA LPMPs showed high anti-NSCLC effects after pulmonary delivery. In conclusion, LPMPs are promising dry powder inhalations for in situ treatment of lung cancer.

  11. Electrospray of multifunctional microparticles for image-guided drug delivery

    NASA Astrophysics Data System (ADS)

    Zhang, Leilei; Yan, Yan; Mena, Joshua; Sun, Jingjing; Letson, Alan; Roberts, Cynthia; Zhou, Chuanqing; Chai, Xinyu; Ren, Qiushi; Xu, Ronald

    2012-03-01

    Anti-VEGF therapies have been widely explored for the management of posterior ocular disease, like neovascular age-related macular degeneration (AMD). Loading anti-VEGF therapies in biodegradable microparticles may enable sustained drug release and improved therapeutic outcome. However, existing microfabrication processes such as double emulsification produce drug-loaded microparticles with low encapsulation rate and poor antibody bioactivity. To overcome these limitations, we fabricate multifunctional microparticles by both single needle and coaxial needle electrospray. The experimental setup for the process includes flat-end syringe needles (both single needle and coaxial needle), high voltage power supplies, and syringe pumps. Microparticles are formed by an electrical field between the needles and the ground electrode. Droplet size and morphology are controlled by multiple process parameters and material properties, such as flow rate and applied voltage. The droplets are collected and freezing dried to obtain multifunctional microparticles. Fluorescent beads encapsulated poly(DL-lactide-co-glycolide) acid (PLGA) microparticles are injected into rabbits eyes through intravitreal injection to test the biodegradable time of microparticles.

  12. An overview of poly(lactic-co-glycolic) acid (PLGA)-based biomaterials for bone tissue engineering.

    PubMed

    Gentile, Piergiorgio; Chiono, Valeria; Carmagnola, Irene; Hatton, Paul V

    2014-02-28

    Poly(lactic-co-glycolic) acid (PLGA) has attracted considerable interest as a base material for biomedical applications due to its: (i) biocompatibility; (ii) tailored biodegradation rate (depending on the molecular weight and copolymer ratio); (iii) approval for clinical use in humans by the U.S. Food and Drug Administration (FDA); (iv) potential to modify surface properties to provide better interaction with biological materials; and (v) suitability for export to countries and cultures where implantation of animal-derived products is unpopular. This paper critically reviews the scientific challenge of manufacturing PLGA-based materials with suitable properties and shapes for specific biomedical applications, with special emphasis on bone tissue engineering. The analysis of the state of the art in the field reveals the presence of current innovative techniques for scaffolds and material manufacturing that are currently opening the way to prepare biomimetic PLGA substrates able to modulate cell interaction for improved substitution, restoration, or enhancement of bone tissue function.

  13. An Overview of Poly(lactic-co-glycolic) Acid (PLGA)-Based Biomaterials for Bone Tissue Engineering

    PubMed Central

    Gentile, Piergiorgio; Chiono, Valeria; Carmagnola, Irene; Hatton, Paul V.

    2014-01-01

    Poly(lactic-co-glycolic) acid (PLGA) has attracted considerable interest as a base material for biomedical applications due to its: (i) biocompatibility; (ii) tailored biodegradation rate (depending on the molecular weight and copolymer ratio); (iii) approval for clinical use in humans by the U.S. Food and Drug Administration (FDA); (iv) potential to modify surface properties to provide better interaction with biological materials; and (v) suitability for export to countries and cultures where implantation of animal-derived products is unpopular. This paper critically reviews the scientific challenge of manufacturing PLGA-based materials with suitable properties and shapes for specific biomedical applications, with special emphasis on bone tissue engineering. The analysis of the state of the art in the field reveals the presence of current innovative techniques for scaffolds and material manufacturing that are currently opening the way to prepare biomimetic PLGA substrates able to modulate cell interaction for improved substitution, restoration, or enhancement of bone tissue function. PMID:24590126

  14. Stabilization of Human Immunoglobulin G Encapsulated within Biodegradable Poly (Cyclohexane-1, 4-diyl Acetone Dimethylene Ketal) (PCADK)/ Poly (Lactic-co-Glycolic Acid) (PLGA) Blend Microspheres.

    PubMed

    Wang, Chenhui; Yu, Changhui; Liu, Jiaxin; Sun, Fengying; Teng, Lesheng; Li, Youxin

    2015-01-01

    The aim of this study was to prepare PCADK/PLGA-blend microspheres for improving the stability of human immunoglobulin G (IgG). The short half-life of antibodies limit their development as therapeutic agents, thus PLGA microspheres were prepared to sustained release antibodies and prolong their half-life. However, the acidic intra-microsphere environment causes the loss of antibody stability and activity. In this study, the effect of PCADK or PLGA degradation products on IgG was investigated by size exclusion chromatography (SEC-HPLC), circular dichroism (CD), fluorescence spectroscopy and antigenicity detection. The degradation products of PCADK exerted a larger influence on IgG than that of PLGA. Then PCADK/PLGA microspheres were prepared by the emulsionsolvent evaporation method and systematically characterized and 20% PCADK were selected as the optimal proportion. In addition, the release profile of microspheres and the stability of the released IgG were investigated. The stability of the IgG released from the PCADK/PLGA microspheres was better than that of IgG released from the PLGA microspheres. Confocal laser scanning microscopy (CLSM) was used to determine the pH inside the microspheres. The IgG-loaded PCADK/PLGA microspheres have important advantages over the PLGA microspheres in terms of IgG stability and could be a good carrier to deliver antibodies for the treatment of disease.

  15. Humidity-dependent compression-induced glass transition of the air-water interfacial Langmuir films of poly(D,L-lactic acid-ran-glycolic acid) (PLGA).

    PubMed

    Kim, Hyun Chang; Lee, Hoyoung; Jung, Hyunjung; Choi, Yun Hwa; Meron, Mati; Lin, Binhua; Bang, Joona; Won, You-Yeon

    2015-07-28

    Constant rate compression isotherms of the air-water interfacial Langmuir films of poly(D,L-lactic acid-ran-glycolic acid) (PLGA) show a distinct feature of an exponential increase in surface pressure in the high surface polymer concentration regime. We have previously demonstrated that this abrupt increase in surface pressure is linked to the glass transition of the polymer film, but the detailed mechanism of this process is not fully understood. In order to obtain a molecular-level understanding of this behavior, we performed extensive characterizations of the surface mechanical, structural and rheological properties of Langmuir PLGA films at the air-water interface, using combined experimental techniques including the Langmuir film balance, X-ray reflectivity and double-wall-ring interfacial rheometry methods. We observed that the mechanical and structural responses of the Langmuir PLGA films are significantly dependent on the rate of film compression; the glass transition was induced in the PLGA film only at fast compression rates. Surprisingly, we found that this deformation rate dependence is also dependent on the humidity of the environment. With water acting as a plasticizer for the PLGA material, the diffusion of water molecules through the PLGA film seems to be the key factor in the determination of the glass transformation properties and thus the mechanical response of the PLGA film against lateral compression. Based on our combined results, we hypothesize the following mechanism for the compression-induced glass transformation of the Langmuir PLGA film; (1) initially, a humidified/non-glassy PLGA film is formed in the full surface-coverage region (where the surface pressure shows a plateau) during compression; (2) further compression leads to the collapse of the PLGA chains and the formation of new surfaces on the air side of the film, and this newly formed top layer of the PLGA film is transiently glassy in character because the water evaporation rate

  16. Cellular uptake, antioxidant and antiproliferative activity of entrapped α-tocopherol and γ-tocotrienol in poly (lactic-co-glycolic) acid (PLGA) and chitosan covered PLGA nanoparticles (PLGA-Chi).

    PubMed

    Alqahtani, Saeed; Simon, Lacey; Astete, Carlos E; Alayoubi, Alaadin; Sylvester, Paul W; Nazzal, Sami; Shen, Yixiao; Xu, Zhimin; Kaddoumi, Amal; Sabliov, Cristina M

    2015-05-01

    The aim of this study was to formulate and characterize α-tocopherol (α-T) and tocotrienol-rich fraction (TRF) entrapped in poly (lactide-co-glycolide) (PLGA) and chitosan covered PLGA (PLGA-Chi) based nanoparticles. The resultant nanoparticles were characterized and the effect of nanoparticles entrapment on the cellular uptake, antioxidant, and antiproliferative activity of α-T and TRF were tested. In vitro uptake studies in Caco2 cells showed that PLGA and PLGA-Chi nanoparticles displayed a greater enhancement in the cellular uptake of α-T and TRF when compared with the control without causing toxicity to the cells (p<0.0001). Furthermore, the cellular internalization of both PLGA and PLGA-Chi nanoparticles labeled with FITC was investigated by fluorescence microscopy; both types of nanoparticles were able to get internalized into the cells with reasonable amounts. However, PLGA-Chi nanoparticles showed significantly higher (3.5-fold) cellular uptake compared to PLGA nanoparticles. The antioxidant activity studies demonstrated that entrapment of α-T and TRF in PLGA and PLGA-Chi nanoparticles exhibited greater ability in inhibiting cholesterol oxidation at 48 h compared to the control. In vitro antiproliferative studies confirmed marked cytotoxicity of TRF on MCF-7 and MDA-MB-231 cell lines when delivered by PLGA and PLGA-Chi nanoparticles after 48 h incubation compared to control. In summary, PLGA and PLGA-Chi nanoparticles may be considered as an attractive and promising approach to enhance the bioavailability and activity of poorly water soluble compounds such as α-tocopherol and tocotrienols.

  17. Hyaluronic acid grafted PLGA copolymer nanoparticles enhance the targeted delivery of Bromelain in Ehrlich's Ascites Carcinoma.

    PubMed

    Bhatnagar, Priyanka; Pant, Aditya Bhushan; Shukla, Yogeshwer; Panda, Amulya; Gupta, Kailash Chand

    2016-08-01

    Rapidly increasing malignant neoplastic disease demands immediate attention. Several dietary compounds have recently emerged as strong anti-cancerous agents. Among, Bromelain (BL), a protease from pineapple plant, was used to enhance its anti-cancerous efficacy using nanotechnology. In lieu of this, hyaluronic acid (HA) grafted PLGA copolymer, having tumor targeting ability, was developed. BL was encapsulated in copolymer to obtain BL-copolymer nanoparticles (NPs) that ranged between 140 to 281nm in size. NPs exhibited higher cellular uptake and cytotoxicity in cells with high CD44 expression as compared with non-targeted NPs. In vivo results on tumor bearing mice showed that NPs were efficient in suppressing the tumor growth. Hence, the formulation could be used as a self-targeting drug delivery cargo for the remission of cancer.

  18. Aspartic acid-based modified PLGA-PEG nanoparticles for bone targeting: in vitro and in vivo evaluation.

    PubMed

    Fu, Yin-Chih; Fu, Tzu-Fun; Wang, Hung-Jen; Lin, Che-Wei; Lee, Gang-Hui; Wu, Shun-Cheng; Wang, Chih-Kuang

    2014-11-01

    Nanoparticles (NP) that target bone tissue were developed using PLGA-PEG (poly(lactic-co-glycolic acid)-polyethylene glycol) diblock copolymers and bone-targeting moieties based on aspartic acid, (Asp)(n(1,3)). These NP are expected to enable the transport of hydrophobic drugs. The molecular structures were examined by (1)H NMR or identified using mass spectrometry and Fourier transform infrared (FT-IR) spectra. The NP were prepared using the water miscible solvent displacement method, and their size characteristics were evaluated using transmission electron microscopy (TEM) and dynamic light scattering. The bone targeting potential of the NP was evaluated in vitro using hydroxyapatite affinity assays and in vivo using fluorescent imaging in zebrafish and rats. It was confirmed that the average particle size of the NP was <200 nm and that the dendritic Asp3 moiety of the PLGA-PEG-Asp3 NP exhibited the best apatite mineral binding ability. Preliminary findings in vivo bone affinity assays in zebrafish and rats indicated that the PLGA-PEG-ASP3 NP may display increased bone-targeting efficiency compared with other PLGA-PEG-based NP that lack a dendritic Asp3 moiety. These NP may act as a delivery system for hydrophobic drugs, warranting further evaluation of the treatment of bone disease.

  19. Multifunctional PLGA particles containing poly(l-glutamic acid)-capped silver nanoparticles and ascorbic acid with simultaneous antioxidative and prolonged antimicrobial activity.

    PubMed

    Stevanović, Magdalena; Bračko, Ines; Milenković, Marina; Filipović, Nenad; Nunić, Jana; Filipič, Metka; Uskoković, Dragan P

    2014-01-01

    A water-soluble antioxidant (ascorbic acid, vitamin C) was encapsulated together with poly(l-glutamic acid)-capped silver nanoparticles (AgNpPGA) within a poly(lactide-co-glycolide) (PLGA) polymeric matrix and their synergistic effects were studied. The PLGA/AgNpPGA/ascorbic acid particles synthesized by a physicochemical method with solvent/non-solvent systems are spherical, have a mean diameter of 775 nm and a narrow size distribution with a polydispersity index of 0.158. The encapsulation efficiency of AgNpPGA/ascorbic acid within PLGA was determined to be >90%. The entire amount of encapsulated ascorbic acid was released in 68 days, and the entire amount of AgNpPGAs was released in 87 days of degradation. The influence of PLGA/AgNpPGA/ascorbic acid on cell viability, generation of reactive oxygen species (ROS) in HepG2 cells, as well as antimicrobial activity against seven different pathogens was investigated. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay indicated good biocompatibility of these PLGA/AgNpPGA/ascorbic acid particles. We measured the kinetics of ROS formation in HepG2 cells by a DCFH-DA assay, and found that PLGA/AgNpPGA/ascorbic acid caused a significant decrease in DCF fluorescence intensity, which was 2-fold lower than that in control cells after a 5h exposure. This indicates that the PLGA/AgNpPGA/ascorbic acid microspheres either act as scavengers of intracellular ROS and/or reduce their formation. Also, the results of antimicrobial activity of PLGA/AgNpPGA/ascorbic acid obtained by the broth microdilution method showed superior and extended activity of these particles. The samples were characterized using Fourier transform infrared spectroscopy, field-emission scanning electron microscopy, transmission electron microscopy, zeta potential and particle size analysis. This paper presents a new approach to the treatment of infection that at the same time offers a very pronounced antioxidant effect.

  20. cmRNA/lipoplex encapsulation in PLGA microspheres enables transfection via calcium phosphate cement (CPC)/PLGA composites.

    PubMed

    Utzinger, Maximilian; Jarzebinska, Anita; Haag, Nicolas; Schweizer, Martin; Winter, Gerhard; Dohmen, Christian; Rudolph, Carsten; Plank, Christian

    2017-03-10

    In this study lipoplexes containing chemically modified messenger RNA (cmRNA) were incorporated into poly (lactic-co-glycolic acid) (PLGA) microspheres via water-in-oil-in-water (W/O/W) double emulsion solvent evaporation technique. The nanoparticle encapsulation by microparticle formation was optimized to achieve lipoplex release and maximum transfection efficiency in surrounding cells. It was possible to adjust characteristic features in surface topology and size of the PLGA-microspheres by varying the extent of lipoplex loading into the polymer matrix. The partial release of lipids and mRNA out of the microparticle system, their accumulation in cells and the production of encoded protein were visualized via fluorescence microscopy. These bioactive microspheres, containing cmRNA bearing lipoplexes, were developed for the incorporation of a therapeutic component into injectable calcium phosphate cements (CPC). Due to the incorporation of PLGA/lipoplex microspheres as a degradable entity, the porosity of the cement phase could additionally be adjusted. This approach of complex nanoparticle incorporation into polymer/cement composites represents a promising example for combining transcript therapy with biomechanical engineering.

  1. Release Kinetic in Yogurt from Gallic Acid Microparticles with Chemically Modified Inulin.

    PubMed

    García, Paula; Vergara, Cristina; Robert, Paz

    2015-10-01

    Gallic acid (GA) was encapsulated with native (NIn), cross-linked (CIn) and acetylated (AIn) inulin by spray-drying. Inulin microparticles were characterized by encapsulation efficiency (EE) and their release profile in yogurt. The EE was significantly higher for GA-CIn (98%) compared with GA-NIn (81%) and GA-AIn (77%) microparticles, showing the effect of the modification of inulin on interaction of GA-polymer. GA release profile data in yogurt for GA-CIn, GA-NIn and GA-AIn were fitted to Peppas and Higuchi models in order to obtain the GA release rate constant. Although the GA release rate constants were significantly different among systems, these differences were slight and the GA release was fast (80% < 2 h) in the three systems, showing that inulin-systems did not control GA release in yogurt. The mechanism of GA release followed a Fickian diffusion and relaxation of chains for all microparticles. According to the release profile, these microparticles would be best suited for use in instant foods.

  2. Hierarchical assembly of viral nanotemplates with encoded microparticles via nucleic acid hybridization.

    PubMed

    Tan, Wui Siew; Lewis, Christina L; Horelik, Nicholas E; Pregibon, Daniel C; Doyle, Patrick S; Yi, Hyunmin

    2008-11-04

    We demonstrate hierarchical assembly of tobacco mosaic virus (TMV)-based nanotemplates with hydrogel-based encoded microparticles via nucleic acid hybridization. TMV nanotemplates possess a highly defined structure and a genetically engineered high density thiol functionality. The encoded microparticles are produced in a high throughput microfluidic device via stop-flow lithography (SFL) and consist of spatially discrete regions containing encoded identity information, an internal control, and capture DNAs. For the hybridization-based assembly, partially disassembled TMVs were programmed with linker DNAs that contain sequences complementary to both the virus 5' end and a selected capture DNA. Fluorescence microscopy, atomic force microscopy (AFM), and confocal microscopy results clearly indicate facile assembly of TMV nanotemplates onto microparticles with high spatial and sequence selectivity. We anticipate that our hybridization-based assembly strategy could be employed to create multifunctional viral-synthetic hybrid materials in a rapid and high-throughput manner. Additionally, we believe that these viral-synthetic hybrid microparticles may find broad applications in high capacity, multiplexed target sensing.

  3. Highly Stable PEGylated Poly(lactic-co-glycolic acid) (PLGA) Nanoparticles for the Effective Delivery of Docetaxel in Prostate Cancers

    NASA Astrophysics Data System (ADS)

    Cao, Long-Bin; Zeng, Sha; Zhao, Wei

    2016-06-01

    In the present study, a highly stable luteinizing-hormone-releasing hormone (LHRH)-conjugated PEGylated poly(lactic-co-glycolic acid) (PLGA) nanoparticles were developed for the successful treatment of prostate cancers. We have demonstrated that a unique combination of targeted drug delivery and controlled drug release is effective against prostate cancer therapy. The docetaxel (DTX)/PLGA-LHRH micelles possessed a uniform spherical shape with an average diameter of ~170 nm. The micelles exhibited a controlled drug release for up to 96 h which can minimize the non-specific systemic spread of toxic drugs during circulation while maximizing the efficiency of tumor-targeted drug delivery. The LHRH-conjugated micelles showed enhanced cellular uptake and exhibited significantly higher cytotoxicity against LNCaP cancer cells. We have showed that PLGA-LHRH induced greater caspase-3 activity indicating its superior apoptosis potential. Consistently, LHRH-conjugated micelles induced threefold and twofold higher G2/M phase arrest than compared to free DTX or PLGA NP-treated groups. Overall, results indicate that use of LHRH-conjugated nanocarriers may potentially be an effective nanocarrier to effectively treat prostate cancer.

  4. Multimodal delivery of irinotecan from microparticles with two distinct compartments.

    PubMed

    Rahmani, Sahar; Park, Tae-Hong; Dishman, Acacia Frances; Lahann, Joerg

    2013-11-28

    In the last several decades, research in the field of drug delivery has been challenged with the fabrication of carrier systems engineered to deliver therapeutics to the target site with sustained and controlled release kinetics. Herein, we report the fabrication of microparticles composed of two distinct compartments: i) one compartment containing a pH responsive polymer, acetal-modified dextran, and PLGA (polylactide-co-glycolide), and ii) one compartment composed entirely of PLGA. We demonstrate the complete release of dextran from the microparticles during a 10-hour period in an acidic pH environment and the complete degradation of one compartment in less than 24h. This is in congruence with the stability of the same microparticles in neutral pH over the 24-hour period. Such microparticles can be used as pH responsive carrier systems for drug delivery applications where their cargo will only be released when the optimum pH window is reached. The feasibility of the microparticle system for such an application was confirmed by encapsulating a cancer therapeutic, irinotecan, in the compartment containing the acetal-modified dextran polymer and the pH dependent release over a 5-day period was studied. It was found that upon pH change to an acidic environment, over 50% of the drug was first released at a rapid rate for 10h, similar to that observed for the dextran release, before continuing at a more controlled rate for 4 days. As such, these microparticles can play an important role in the fabrication of novel drug delivery systems due to the selective, controlled, and pH responsive release of their encapsulated therapeutics.

  5. Ascorbic acid supplementation diminishes microparticle elevations and neutrophil activation following SCUBA diving.

    PubMed

    Yang, Ming; Barak, Otto F; Dujic, Zeljko; Madden, Dennis; Bhopale, Veena M; Bhullar, Jasjeet; Thom, Stephen R

    2015-08-15

    Predicated on evidence that diving-related microparticle generation is an oxidative stress response, this study investigated the role that oxygen plays in augmenting production of annexin V-positive microparticles associated with open-water SCUBA diving and whether elevations can be abrogated by ascorbic acid. Following a cross-over study design, 14 male subjects ingested placebo and 2-3 wk later ascorbic acid (2 g) daily for 6 days prior to performing either a 47-min dive to 18 m of sea water while breathing air (∼222 kPa N2/59 kPa O2) or breathing a mixture of 60% O2/balance N2 from a tight-fitting face mask at atmospheric pressure for 47 min (∼40 kPa N2/59 kPa O2). Within 30 min after the 18-m dive in the placebo group, neutrophil activation, and platelet-neutrophil interactions occurred, and the total number of microparticles, as well as subgroups bearing CD66b, CD41, CD31, CD142 proteins or nitrotyrosine, increased approximately twofold. No significant elevations occurred among divers after ingesting ascorbic acid, nor were elevations identified in either group after breathing 60% O2. Ascorbic acid had no significant effect on post-dive intravascular bubble production quantified by transthoracic echocardiography. We conclude that high-pressure nitrogen plays a key role in neutrophil and microparticle-associated changes with diving and that responses can be abrogated by dietary ascorbic acid supplementation.

  6. Microparticle-mediated gene delivery for the enhanced expression of a 19-kDa fragment of merozoite surface protein 1 of Plasmodium falciparum.

    PubMed

    Liu, Shan; Danquah, Michael K; Forde, Gareth M; Ma, Charles; Wang, Lina; Coppel, Ross

    2010-01-01

    The 19 kDa carboxyl-terminal fragment of merozoite surface protein 1 (MSP1(19)) is a major component of the invasion-inhibitory response in individual immunity to malaria. A novel ultrasonic atomization approach for the formulation of biodegradable poly(lactic-co-glycolic acid) (PLGA) microparticles of malaria DNA vaccines encoding MSP1(19) is presented here. After condensing the plasmid DNA (pDNA) molecules with a cationic polymer polyethylenimine (PEI), a 40 kHz ultrasonic atomization frequency was used to formulate PLGA microparticles at a flow rate of 18 mL h(-1). High levels of gene expression and moderate cytotoxicity in COS-7 cells were achieved with the condensed pDNA at a nitrogen to phosphate (N/P) ratio of 20, thus demonstrating enhanced cellular uptake and expression of the transgene. The ability of the microparticles to convey pDNA was examined by characterizing the formulated microparticles. The microparticles displayed Z-average hydrodynamic diameters of 1.50-2.10 microm and zeta potentials of 17.8-23.2 mV. The encapsulation efficiencies were between 78 and 83%, and 76 and 85% of the embedded malaria pDNA molecules were released under physiological conditions in vitro. These results indicate that PLGA-mediated microparticles can be employed as potential gene delivery systems to antigen-presenting cells in the prevention of malaria.

  7. Effects of Antibiotic Physicochemical Properties on their Release Kinetics from Biodegradable Polymer Microparticles

    PubMed Central

    Shah, Sarita R.; Henslee, Allan M.; Spicer, Patrick P.; Yokota, Shun; Petrichenko, Sophia; Allahabadi, Sachin; Bennett, George N.; Wong, Mark E.; Kasper, F. Kurtis; Mikos, Antonios G.

    2014-01-01

    Purpose This study investigated the effects of the physicochemical properties of antibiotics on the morphology, loading efficiency, size, release kinetics, and antibiotic efficacy of loaded poly(DL-lactic-co-glycolic acid) (PLGA) microparticles (MPs) at different loading percentages. Methods Cefazolin, ciprofloxacin, clindamycin, colistin, doxycycline, and vancomycin were loaded at 10 and 20 weight percent into PLGA MPs using a water-in-oil-in water double emulsion fabrication protocol. Microparticle morphology, size, loading efficiency, release kinetics, and antibiotic efficacy were assessed. Results The results from this study demonstrate that the chemical nature of loaded antibiotics, especially charge and molecular weight, influence the incorporation into and release of antibiotics from PLGA MPs. Drugs with molecular weights less than 600 Da displayed biphasic release while those with molecular weights greater than 1000 Da displayed triphasic release kinetics. Large molecular weight drugs also had a longer delay before release than smaller molecular weight drugs. The negatively charged antibiotic cefazolin had lower loading efficiency than positively charged antibiotics. Microparticle size appeared to be mainly controlled by fabrication parameters, and partition and solubility coefficients did not appear to have an obvious effect on loading efficiency or release. Released antibiotics maintained their efficacy against susceptible strains over the duration of release. Duration of release varied between 17–49 days based on the type of antibiotic loaded. Conclusions The data from this study indicate that the chemical nature of antibiotics affects properties of antibiotic-loaded PLGA MPs and allows for general prediction of loading and release kinetics. PMID:24874603

  8. New Perspective in the Formulation and Characterization of Didodecyldimethylammonium Bromide (DMAB) Stabilized Poly(Lactic-co-Glycolic Acid) (PLGA) Nanoparticles

    PubMed Central

    Gossmann, Rebecca; Langer, Klaus; Mulac, Dennis

    2015-01-01

    Over the last few decades the establishment of nanoparticles as suitable drug carriers with the transport of drugs across biological barriers such as the gastrointestinal barrier moved into the focus of many research groups. Besides drug transport such carrier systems are well suited for the protection of drugs against enzymatic and chemical degradation. The preparation of biocompatible and biodegradable nanoparticles based on poly(lactic-co-glycolic acid) (PLGA) is intensively described in literature, while especially nanoparticles with cationic properties show a promising increased cellular uptake. This is due to the electrostatic interaction between the cationic surface and the negatively charged lipid membrane of the cells. Even though several studies achieved the successful preparation of nanoparticles stabilized with the cationic surfactants such as didodecyldimethylammonium bromide (DMAB), in most cases insufficient attention was paid to a precise analytical characterization of the nanoparticle system. The aim of the present work was to overcome this deficit by presenting a new perspective in the formulation and characterization of DMAB-stabilized PLGA nanoparticles. Therefore these nanoparticles were carefully examined with regard to particle diameter, zeta potential, the effect of variation in stabilizer concentration, residual DMAB content, and electrolyte stability. Without any steric stabilization, the DMAB-modified nanoparticles were sensitive to typical electrolyte concentrations of biological environments due to compression of the electrical double layer in conjunction with a decrease in zeta potential. To handle this problem, the present study proposed two modifications to enable electrolyte stability. Both polyvinyl alcohol (PVA) and polyethylene glycol (PEG) modified DMAB-PLGA-nanoparticles were stable during electrolyte addition. Furthermore, in contrast to unmodified DMAB-PLGA-nanoparticles and free DMAB, such modifications led to a lower

  9. Poly(N-vinylcaprolactam-co-methacrylic acid) hydrogel microparticles for oral insulin delivery.

    PubMed

    Mundargi, Raghavendra C; Rangaswamy, Vidhya; Aminabhavi, Tejraj M

    2011-01-01

    pH-sensitive copolymeric hydrogels prepared from N-vinylcaprolactam and methacrylic acid monomers by free radical polymerization offered 52% encapsulation efficiency and evaluated for oral delivery of human insulin. The in vitro experiments performed on insulin-loaded microparticles in pH 1.2 media (stomach condition) demonstrated no release of insulin in the first 2 h, but almost 100% insulin was released in pH 7.4 media (intestinal condition) in 6 h. The carrier was characterized by Fourier transform infrared, differential scanning calorimeter, thermogravimetry and nuclear magnetic resonance techniques to confirm the formation of copolymer, while scanning electron microscopy was used to assess the morphology of hydrogel microparticles. The in vivo experiments on alloxan-induced diabetic rats showed the biological inhibition up to 50% and glucose tolerance tests exhibited 44% inhibition. The formulations of this study are the promising carriers for oral delivery of insulin.

  10. Treatment of Mycobacterium tuberculosis-Infected Macrophages with Poly(Lactic-Co-Glycolic Acid) Microparticles Drives NFκB and Autophagy Dependent Bacillary Killing.

    PubMed

    Lawlor, Ciaran; O'Connor, Gemma; O'Leary, Seonadh; Gallagher, Paul J; Cryan, Sally-Ann; Keane, Joseph; O'Sullivan, Mary P

    2016-01-01

    The emergence of multiple-drug-resistant tuberculosis (MDR-TB) has pushed our available repertoire of anti-TB therapies to the limit of effectiveness. This has increased the urgency to develop novel treatment modalities, and inhalable microparticle (MP) formulations are a promising option to target the site of infection. We have engineered poly(lactic-co-glycolic acid) (PLGA) MPs which can carry a payload of anti-TB agents, and are successfully taken up by human alveolar macrophages. Even without a drug cargo, MPs can be potent immunogens; yet little is known about how they influence macrophage function in the setting of Mycobacterium tuberculosis (Mtb) infection. To address this issue we infected THP-1 macrophages with Mtb H37Ra or H37Rv and treated with MPs. In controlled experiments we saw a reproducible reduction in bacillary viability when THP-1 macrophages were treated with drug-free MPs. NFκB activity was increased in MP-treated macrophages, although cytokine secretion was unaltered. Confocal microscopy of immortalized murine bone marrow-derived macrophages expressing GFP-tagged LC3 demonstrated induction of autophagy. Inhibition of caspases did not influence the MP-induced restriction of bacillary growth, however, blockade of NFκB or autophagy with pharmacological inhibitors reversed this MP effect on macrophage function. These data support harnessing inhaled PLGA MP-drug delivery systems as an immunotherapeutic in addition to serving as a vehicle for targeted drug delivery. Such "added value" could be exploited in the generation of inhaled vaccines as well as inhaled MDR-TB therapeutics when used as an adjunct to existing treatments.

  11. Green microparticles based on a chitosan/lactobionic acid/linoleic acid association. Characterization and evaluation as a new carrier system for cosmetics.

    PubMed

    Chaouat, C; Balayssac, S; Malet-Martino, M; Belaubre, F; Questel, E; Schmitt, A M; Poigny, S; Franceschi, S; Perez, E

    2017-03-27

    The association chitosan/linoleic acid/lactobionic acid in aqueous solution spontaneously led to the formation of stable microparticles with a liquid hydrophobic core consisting of linoleic acid surrounded by a shell of chitosan/lactobionic acid. The originality of the microparticles arises from the fact that they are formed by the association of three ingredients of cosmetic interest, including a skin penetration enhancer (linoleic acid). DLS measurements showed microparticles with a mean diameter of 1 to 2 µm. The presence of a hydrophobic liquid core was observed by TEM. The ability of these microparticles to encapsulate phenylethyl resorcinol, a hydrophobic skin lightener, was evaluated and its encapsulation was confirmed thanks to T2 measurements and nOe signs.

  12. Improved insulin loading in poly(lactic-co-glycolic) acid (PLGA) nanoparticles upon self-assembly with lipids.

    PubMed

    García-Díaz, María; Foged, Camilla; Nielsen, Hanne Mørck

    2015-03-30

    Polymeric nanoparticles are widely investigated as drug delivery systems for oral administration. However, the hydrophobic nature of many polymers hampers effective loading of the particles with hydrophilic macromolecules such as insulin. Thus, the aim of this work was to improve the loading of insulin into poly(lactic-co-glycolic) acid (PLGA) nanoparticles by pre-assembly with amphiphilic lipids. Insulin was complexed with soybean phosphatidylcholine or sodium caprate by self-assembly and subsequently loaded into PLGA nanoparticles by using the double emulsion-solvent evaporation technique. The nanoparticles were characterized in terms of size, zeta potential, insulin encapsulation efficiency and loading capacity. Upon pre-assembly with lipids, there was an increased distribution of insulin into the organic phase of the emulsion, eventually resulting in significantly enhanced encapsulation efficiencies (90% as compared to 24% in the absence of lipids). Importantly, the insulin loading capacity was increased up to 20% by using the lipid-insulin complexes. The results further showed that a main fraction of the lipid was incorporated into the nanoparticles and remained associated to the polymer during release studies in buffers, whereas insulin was released in a non-complexed form as a burst of approximately 80% of the loaded insulin. In conclusion, the protein load in PLGA nanoparticles can be significantly increased by employing self-assembled protein-lipid complexes.

  13. Diaminosulfide based polymer microparticles as cancer vaccine delivery systems.

    PubMed

    Geary, Sean M; Hu, Qiaohong; Joshi, Vijaya B; Bowden, Ned B; Salem, Aliasger K

    2015-12-28

    The aim of the research presented here was to determine the characteristics and immunostimulatory capacity, in vivo, of antigen and adjuvant co-loaded into microparticles made from a novel diaminosulfide polymer, poly(4,4'-trimethylenedipiperdyl sulfide) (PNSN), and to assess their potential as cancer vaccine vectors. PNSN microparticles co-loaded with the antigen, ovalbumin (OVA), and adjuvant, CpG 1826, (PNSN(OVA + CpG)) were fabricated and characterized for size (1.64 μm diameter; PDI=0.62), charge (-23.1 ± 0.3), and loading efficiencies of antigen (7.32 μg/mg particles) and adjuvant (0.95 μg/mg particles). The ability of PNSN(OVA + CpG) to stimulate cellular and humoral immune responses in vivo was compared with other PNSN microparticle formulations as well as with poly(lactic-co-glycolic acid)(PLGA)-based microparticles, co-loaded with OVA and CpG (PLGA(OVA + CpG)), an adenovirus encoding OVA (Ad5-OVA), and OVA delivered with incomplete Freund's adjuvant (IFA(OVA)). In vivo OVA-specific IgG1 responses, after subcutaneous prime/boosts in mice, were similar when PNSN(OVA + CpG) and PLGA(OVA + CpG) were compared and the presence of CpG 1826 within the PNSN microparticles demonstrated significantly improved responses when compared to PNSN microparticles loaded with OVA alone (PNSN(OVA)), plus or minus soluble CpG 1826. Cellular immune responses to all particle-based vaccine formulations ranged from being negligible to modest with PNSN(OVA + CpG) generating the greatest responses, displaying significantly increased levels of OVA-specific CD8+ T lymphocytes compared to controls and IFA(OVA) treated mice. Finally, it was shown that of all vaccination formulations tested PNSN(OVA + CpG) was the most protective against subsequent challenge with an OVA-expressing tumor cell line, E.G7. Thus, microparticles made from poly(diaminosulfide)-based macromolecules possess promising potential as vaccine vectors and, as demonstrated here, may have impact as cancer vaccines

  14. Production and characterization of hyaluronic acid microparticles for the controlled delivery of growth factors using a spray/dehydration method.

    PubMed

    Babo, Pedro S; Reis, Rui L; Gomes, Manuela E

    2016-11-01

    Hyaluronic acid is the main polysaccharide present in the connective tissue. Besides its structural function as backbone of the extracellular matrix, hyaluronic acid plays staple roles in several biological processes including the modulation of inflammation and wound healing processes. The application of hyaluronic acid in regenerative medicine, either as cells and/or drug/growth factors delivery vehicles, relies on its ability to be cross-linked using a plethora of reactions, producing stable hydrogels. In this work, we propose a novel method for the production of hyaluronic acid microparticles that presents several advantages over others that have been used. Basically, droplets of hyaluronic acid solution produced with a nozzle are collected in an isopropanol dehydration bath, and stabilized after crosslinking with adipic acid dihydrazide, using a cabodiimide-based chemistry. The size and morphology of the hyaluronic acid microparticles produced by this method varied with the molecular weight and concentration of the hyaluronic acid solution, the nozzle chamber pressure, the distance between the nozzle and the crosslinking solution, and the number of crosslinking steps. The degree of crosslinking of the hyaluronic acid microparticles produced was tunable and allowed to control the rate of the degradation promoted by hyaluronidase. Moreover, the particles were loaded with platelet lysate, a hemoderivative rich in cytokines with interest for regenerative medicine applications. The hyaluronic acid microparticles showed potential to bind selectively to positively charged molecules, as the factors present in the platelet lysate. It is envisioned that these can be further released in a sustained manner by ion exchange or by the degradation of the hyaluronic acid microparticles matrix promoted by extracellular matrix remodeling.

  15. Electrospun aligned PLGA and PLGA/gelatin nanofibers embedded with silica nanoparticles for tissue engineering.

    PubMed

    Mehrasa, Mohammad; Asadollahi, Mohammad Ali; Ghaedi, Kamran; Salehi, Hossein; Arpanaei, Ayyoob

    2015-08-01

    Aligned poly lactic-co-glycolic acid (PLGA) and PLGA/gelatin nanofibrous scaffolds embedded with mesoporous silica nanoparticles (MSNPs) were fabricated using electrospinning method. The mean diameters of nanofibers were 641±24 nm for the pure PLGA scaffolds vs 418±85 nm and 267±58 nm for the PLGA/10 wt% MSNPs and the PLGA/gelatin/10 wt% MSNPs scaffolds, respectively. The contact angle measurement results (102°±6.7 for the pure PLGA scaffold vs 81°±6.8 and 18°±8.7 for the PLGA/10 wt% MSNPs and the PLGA/gelatin/10 wt% MSNPs scaffolds, respectively) revealed enhanced hydrophilicity of scaffolds upon incorporation of gelatin and MSNPs. Besides, embedding the scaffolds with MSNPs resulted in improved tensile mechanical properties. Cultivation of PC12 cells on the scaffolds demonstrated that introduction of MSNPs into PLGA and PLGA/gelatin matrices leads to the improved cell attachment and proliferation as well as long cellular processes. DAPI staining results indicated that cell proliferations on the PLGA/10 wt% MSNPs and the PLGA/gelatin/10 wt% MSNPs scaffolds were strikingly (nearly 2.5 and 3 folds, respectively) higher than that on the aligned pure PLGA scaffolds. These results suggest superior properties of silica nanoparticles-incorporated PLGA/gelatin eletrospun nanofibrous scaffolds for the stem cell culture and tissue engineering applications.

  16. Characterisation of the Poly-(Vinylpyrrolidone)-Poly-(Vinylacetate-Co-Crotonic Acid) (PVP:PVAc-CA) Interpolymer Complex Matrix Microparticles Encapsulating a Bifidobacterium lactis Bb12 Probiotic Strain.

    PubMed

    Mamvura, C I; Moolman, F S; Kalombo, L; Hall, A N; Thantsha, M S

    2011-06-01

    The method of producing poly-(vinylpyrrolidone)-poly-(vinylacetate-co-crotonic acid) (PVP:PVAc-CA) interpolymer complex matrix microparticles in supercritical carbon dioxide (scCO2), encapsulating bacteria, has recently been developed. This study was aimed at probing the external and internal structure of these microparticles, which can be used in food. The encapsulation efficiency and distribution of encapsulated Bifidobacterium lactis Bb12 within these microparticles were also investigated. Scanning electron microscopy (SEM) revealed irregular, mostly small, smooth microparticles with no visible bacterial cells on the surface. However, some of the microparticles appeared to have porous surfaces. The results of a Microtrac S3500 particle size analyzer showed that the PVP:PVAc-CA interpolymer complex matrix microparticles encapsulating B. lactis Bb12 had an average particle size of 166.1 μm (<350 μm designated standard size for microparticles). The D 10, D 50 and D 90 values for these microparticles were 48.16, 166.06 and 382.55 μm, respectively. Both SEM and confocal laser scanning microscopy showed a high density of bacterial cells within the microparticles. An average encapsulation efficiency of 96% was achieved. Consequently, the microparticles have the potential to be evenly distributed in foods, deliver adequate amounts of probiotics and produce minimal adverse effects on the texture and mouth feel of the foods into which they are incorporated.

  17. Enhancement and modeling of microparticle-added Rhizopus oryzae lactic acid production.

    PubMed

    Coban, Hasan Bugra; Demirci, Ali

    2016-02-01

    Lactic acid has a wide industrial application area and can be produced by fungal strains. However, excessive bulk growth form of fungi during the fermentations is a major problem, which limits the fermentation performance. Microparticles are excellent tools to prevent bulk fungal growth and provide homogenized fermentation broth to increase uniformity and the prediction performance of the models. Therefore, in this study, addition of aluminum oxide and talcum microparticles into fermentations was evaluated to enhance the production of lactic acid by Rhizopus oryzae. The results showed that the bulk fungal growth was prevented and the lactic acid concentration increased from 6.02 to 13.88 and 24.01 g/L, when 15 g/L of aluminum oxide or 10 g/L of talcum was used, respectively, in the shake-flask fermentations. Additionally, substrate concentration, pH, and agitation were optimized in the bioreactors using response surface methodology, and optimum values were determined as 126 g/L of glucose, 6.22 pH, and 387 rpm, respectively. Under these conditions, lactic acid production further increased to 75.1 ± 1.5 g/L with 10 g/L of talcum addition. Also, lactic acid production and glucose consumption in the batch fermentation were successfully modeled with modified Gompertz model and modified logistic model. RMSE and MAE values for lactic acid production were calculated as 2.279 and 1.498 for the modified Gompertz model; 3.6 and 4.056 for the modified logistic model. Additionally, modified logistic model predicted glucose consumption with -2.088 MAE and 2.868 RMSE, whereas these values were calculated as 2.035 and 3.946 for the modified Gompertz model.

  18. Magnetic microparticles post-synthetically coated by hyaluronic acid as an enhanced carrier for microfluidic bioanalysis.

    PubMed

    Holubova, Lucie; Knotek, Petr; Palarcik, Jiri; Cadkova, Michaela; Belina, Petr; Vlcek, Milan; Korecka, Lucie; Bilkova, Zuzana

    2014-11-01

    Iron oxide based particles functionalized by bioactive molecules have been utilized extensively in biotechnology and biomedicine. Despite their already proven advantages, instability under changing reaction conditions, non-specific sorption of biomolecules on the particles' surfaces, and iron oxide leakage from the naked particles can greatly limit their application. As confirmed many times, surface treatment with an appropriate stabilizer helps to minimize these disadvantages. In this work, we describe enhanced post-synthetic surface modification of superparamagnetic microparticles varying in materials and size using hyaluronic acid (HA) in various chain lengths. Scanning electron microscopy, atomic force microscopy, phase analysis light scattering and laser diffraction are the methods used for characterization of HA-coated particles. The zeta potential and thickness of HA-layer of HA-coated Dynabeads M270 Amine were -50 mV and 85 nm, respectively, and of HA-coated p(GMA-MOEAA)-NH2 were -38 mV and 140 nm, respectively. The electrochemical analysis confirmed the zero leakage of magnetic material and no reactivity of particles with hydrogen peroxide. The rate of non-specific sorption of bovine serum albumin was reduced up to 50% of the naked ones. The coating efficiency and suitability of biopolymer-based microparticles for magnetically active microfluidic devices were confirmed.

  19. Porous silicon oxide-PLGA composite microspheres for sustained ocular delivery of daunorubicin.

    PubMed

    Nan, Kaihui; Ma, Feiyan; Hou, Huiyuan; Freeman, William R; Sailor, Michael J; Cheng, Lingyun

    2014-08-01

    A water-soluble anthracycline antibiotic drug (daunorubicin, DNR) was loaded into oxidized porous silicon (pSiO2) microparticles and then encapsulated with a layer of polymer (poly lactide-co-glycolide, PLGA) to investigate their synergistic effects in control of DNR release. Similarly fabricated PLGA-DNR microspheres without pSiO2, and pSiO2 microparticles without PLGA were used as control particles. The composite microparticles synthesized by a solid-in-oil-in-water emulsion method have mean diameters of 52.33±16.37μm for PLGA-pSiO2_21/40-DNR and the mean diameter of 49.31±8.87μm for PLGA-pSiO2_6/20-DNR. The mean size, 26.00±8μm, of PLGA-DNR was significantly smaller, compared with the other two (P<0.0001). Optical microscopy revealed that PLGA-pSiO2-DNR microspheres contained multiple pSiO2 particles. In vitro release experiments determined that control PLGA-DNR microspheres completely released DNR within 38days and control pSiO2-DNR microparticles (with no PLGA coating) released DNR within 14days, while the PLGA-pSiO2-DNR microspheres released DNR for 74days. Temporal release profiles of DNR from PLGA-pSiO2 composite particles indicated that both PLGA and pSiO2 contribute to the sustained release of the payload. The PLGA-pSiO2 composite displayed a more constant rate of DNR release than the pSiO2 control formulation, and displayed a significantly slower release of DNR than either the PLGA or pSiO2 formulations. We conclude that this system may be useful in managing unwanted ocular proliferation when formulated with antiproliferation compounds such as DNR.

  20. TGF-beta1 release from biodegradable polymer microparticles: its effects on marrow stromal osteoblast function

    NASA Technical Reports Server (NTRS)

    Lu, L.; Yaszemski, M. J.; Mikos, A. G.; McIntire, L. V. (Principal Investigator)

    2001-01-01

    BACKGROUND: Controlled release of transforming growth factor-beta1 (TGF-beta1) to a bone defect may be beneficial for the induction of a bone regeneration cascade. The objectives of this work were to assess the feasibility of using biodegradable polymer microparticles as carriers for controlled TGF-beta1 delivery and the effects of released TGF-beta1 on the proliferation and differentiation of marrow stromal cells in vitro. METHODS: Recombinant human TGF-beta1 was incorporated into microparticles of blends of poly(DL-lactic-co-glycolic acid) (PLGA) and poly(ethylene glycol) (PEG). Fluorescein isothiocynate-labeled bovine serum albumin (FITC-BSA) was co-encapsulated as a porogen. The effects of PEG content (0, 1, or 5% by weight [wt%]) and buffer pH (3, 5, or 7.4) on the protein release kinetics and the degradation of PLGA were determined in vitro for as long as 28 days. Rat marrow stromal cells were seeded on a biodegradable poly(propylene fumarate) (PPF) substrate. The dose response and biological activity of released TGF-beta1 was determined after 3 days in culture. The effects of TGF-beta1 released from PLGA/PEG microparticles on marrow stromal cell proliferation and osteoblastic differentiation were assessed during a 21-day period. RESULTS: TGF-beta1 was encapsulated along with FITC-BSA into PLGA/PEG blend microparticles and released in a multiphasic fashion including an initial burst for as long as 28 days in vitro. Increasing the initial PEG content resulted in a decreased cumulative mass of released proteins. Aggregation of FITC-BSA occurred at lower buffer pH, which led to decreased release rates of both proteins. The degradation of PLGA was increased at higher PEG content and significantly accelerated at acidic pH conditions. Rat marrow stromal cells cultured on PPF substrates showed a dose response to TGF-beta1 released from the microparticles similar to that of added TGF-beta1, indicating that the activity of TGF-beta1 was retained during microparticle

  1. Tannic acid incorporation in chitosan-based microparticles and in vitro controlled release.

    PubMed

    Aelenei, Neculai; Popa, Marcel Ionel; Novac, Ovidiu; Lisa, Gabriela; Balaita, Lacramioara

    2009-05-01

    Chitosan, a natural polycationic polysaccharide, was coupled with two polyanionic polymers: Na-alginate and carboxymethylcellulose (CMC) and with tannic acid (TA) obtaining three species of self-assembled complexes: chitosan/alginate/TA (sample 1), chitosan/TA (sample 2) and chitosan/CMC/TA (sample 3). The microparticle formation was achieved by dropwise addition of one solution into other by using a coaxial airflow sprayer. These systems were characterized with regard to particle size distribution, thermal stability, tannic acid entrapment efficiency. Sample 2 showed quite a different behavior compared to the other two samples; the particle diameter is located in the nanometric region, the quantity of incorporated tannic acid is higher than in the other two samples and the material shows better thermal stability. The release of tannic acid from these complexes was studied in water (pH = 5.89), phosphates buffer (pH = 7.04) and acetate buffer (pH = 4.11). These studies revealed two distinct periods in tannic acid delivery process: an initial period, varying between 4 and 10 h, characterized by a high release rate with a delivered tannic acid amount of approximately 80% of the incorporated polyphenol and a second period, which starts after 20 to 30 h of delivery and it ends after approximately 120 h, when the release process takes place with low and constant rate and the kinetic curve is linear--characteristic for a zero order kinetic.

  2. Acid-Sensitive Sheddable PEGylated PLGA Nanoparticles Increase the Delivery of TNF-α siRNA in Chronic Inflammation Sites

    PubMed Central

    Aldayel, Abdulaziz M; Naguib, Youssef W; O'Mary, Hannah L; Li, Xu; Niu, Mengmeng; Ruwona, Tinashe B; Cui, Zhengrong

    2016-01-01

    There has been growing interest in utilizing small interfering RNA (siRNA) specific to pro-inflammatory cytokines, such as tumor necrosis factor-α ( TNF-α), in chronic inflammation therapy. However, delivery systems that can increase the distribution of the siRNA in chronic inflammation sites after intravenous administration are needed. Herein we report that innovative functionalization of the surface of siRNA-incorporated poly (lactic-co-glycolic) acid (PLGA) nanoparticles significantly increases the delivery of the siRNA in the chronic inflammation sites in a mouse model. The TNF-α siRNA incorporated PLGA nanoparticles were prepared by the standard double emulsion method, but using stearoyl-hydrazone-polyethylene glycol 2000, a unique acid-sensitive surface active agent, as the emulsifying agent, which renders (i) the nanoparticles PEGylated and (ii) the PEGylation sheddable in low pH environment such as that in chronic inflammation sites. In a mouse model of lipopolysaccharide-induced chronic inflammation, the acid-sensitive sheddable PEGylated PLGA nanoparticles showed significantly higher accumulation or distribution in chronic inflammation sites than PLGA nanoparticles prepared with an acid-insensitive emulsifying agent (i.e., stearoyl-amide-polyethylene glycol 2000) and significantly increased the distribution of the TNF-α siRNA incorporated into the nanoparticles in inflamed mouse foot. PMID:27434685

  3. Microspheres prepared with different co-polymers of poly(lactic-glycolic acid) (PLGA) or with chitosan cause distinct effects on macrophages.

    PubMed

    Bitencourt, Claudia da Silva; Silva, Letícia Bueno da; Pereira, Priscilla Aparecida Tartari; Gelfuso, Guilherme Martins; Faccioli, Lúcia Helena

    2015-12-01

    Microencapsulation of bioactive molecules for modulating the immune response during infectious or inflammatory events is a promising approach, since microspheres (MS) protect these labile biomolecules against fast degradation, prolong the delivery over longer periods of time and, in many situations, target their delivery to site of action, avoiding toxic side effects. Little is known, however, about the influence of different polymers used to prepare MS on macrophages. This paper aims to address this issue by evaluating in vitro cytotoxicity, phagocytosis profile and cytokines release from alveolar macrophages (J-774.1) treated with MS prepared with chitosan, and four different co-polymers of PLGA [poly (lactic-co-glycolic acid)]. The five MS prepared presented similar diameter and zeta potential each other. Chitosan-MS showed to be cytotoxic to J-774.1 cells, in contrast to PLGA-MS, which were all innocuous to this cell linage. PLGA 5000-MS was more efficiently phagocytized by macrophages compared to the other MS tested. PLGA 5000-MS and 5002-MS induced significant production of TNF-α, while 5000-MS, 5004-MS and 7502-MS decreased spontaneous IL-6 release. Nevertheless, only PLGA 5002-MS induced significant NFkB/SEAP activation. These findings together show that MS prepared with distinct PLGA co-polymers are differently recognized by macrophages, depending on proportion of lactic and glycolic acid in polymeric chain, and on molecular weight of the co-polymer used. Selection of the most adequate polymer to prepare a microparticulate drug delivery system to modulate immunologic system may take into account, therefore, which kind of immunomodulatory response is more adequate for the required treatment.

  4. Synthesis and characterization of microparticles based on poly-methacrylic acid with glucose oxidase for biosensor applications.

    PubMed

    Hervás Pérez, J P; López-Ruiz, B; López-Cabarcos, E

    2016-01-01

    In the line of the applicability of biocompatible monomers pH and temperature dependent, we assayed poly-methacrylic acid (p-MAA) microparticles as immobilization system in the design of enzymatic biosensors. Glucose oxidase was used as enzyme model for the study of microparticles as immobilization matrices and as biological material in the performance of glucose biosensors. The enzyme immobilization method was optimized by investigating the influence of monomer concentration and cross-linker content (N',N'-methylenebisacrylamide), used in the preparation of the microparticles in the response of the biosensors. The kinetics of the polymerization and the effects of the temperature were studied, also the conversion of the polymerization was determinates by a weight method. The structure of the obtained p-MAA microparticles were studied through scanning electron microscopy (SEM) and differential scanning microscopy (DSC). The particle size measurements were performed with a Galai-Cis 1 particle analyzer system. Furthermore, the influence of the swelling behavior of hydrogel matrix as a function of pH and temperature were studied. Analytical properties such as sensitivity, linear range, response time and detection limit were studied for the glucose biosensors. The sensitivity for glucose detection obtained with poly-methacrylic acid (p-MAA) microparticles was 11.98mAM(-1)cm(-2) and 10μM of detection limit. A Nafion® layer was used to eliminate common interferents of the human serum such as uric and ascorbic acids. The biosensors were used to determine glucose in human serum samples with satisfactory results. When stored in a frozen phosphate buffer solution (pH 6.0) at -4°C, the useful lifetime of all biosensors was at least 550 days.

  5. Osmogen-Mediated One-Step Technique of Fabricating Hollow Microparticles for Encapsulation and Delivery of Bioactive Molecules.

    PubMed

    Kharel, Sharad; Lee, Wei Li; Lee, Xuan Yi; Loo, Say Chye Joachim

    2016-11-16

    Microparticulate systems composed of biodegradable polymers, such as poly(d,l-lactic-co-glycolic acid) (PLGA), are widely used for controlled release of bioactive molecules. However, the acidic microenvironment within these microparticles, as they degrade, has been reported to perturb the configuration of most encapsulated proteins. In addition, these polymer particles are also reported to suffer from unrealistically slow and incomplete release of proteins. To address these drawbacks, hollow PLGA microparticles are fabricated through a novel one-step oil-in-water emulsion solvent evaporation technique, by capitalizing on the osmotic property of an osmogen. The effects of fabrication para-meters on particle size and morphology, i.e., volume space of hollow cavity and shell thickness, are also studied. These hollow microparticles are subsequently loaded with bovine insulin microcrystals. It is shown that insulin release profiles can be tuned by simply changing the amount of osmogen in the formulation. At the same time, these hollow microparticles are shown to be effective in maintaining the bioactivity of the encapsulated protein.

  6. Acid sphingomyelinase is activated in sickle cell erythrocytes and contributes to inflammatory microparticle generation in SCD.

    PubMed

    Awojoodu, Anthony O; Keegan, Philip M; Lane, Alicia R; Zhang, Yuying; Lynch, Kevin R; Platt, Manu O; Botchwey, Edward A

    2014-09-18

    Sphingolipids are a class of lipids containing a backbone of sphingoid bases that can be produced de novo through the reaction of palmitate and serine and further metabolized through the activity of various enzymes to produce intermediates with diverse roles in cellular processes and signal transduction. One of these intermediates, sphingosine 1-phosphate (S1P), is stored at high concentrations (1 μM) in red blood cells (RBCs) and directs a wide array of cellular processes mediated by 5 known G-protein coupled receptors (S1P1-S1P5). In this study, we show that RBC membrane alterations in sickle cell disease enhance the activation acid sphingomyelinase by 13%, resulting in increased production and storage of sphingosine (2.6-fold) and S1P (3.5-fold). We also show that acid sphingomyelinase enhances RBC-derived microparticle (MP) generation. These MPs are internalized by myeloid cells and promote proinflammatory cytokine secretion and endothelial cell adhesion, suggesting that potential crosstalk between circulating inflammatory cells and MPs may contribute to the inflammation-rooted pathogenesis of the disease. Treatment with amitriptyline reduces MP generation in vitro and in vivo and might be used to mitigate inflammatory processes in sickle cell disease.

  7. Down-regulation of Th2 immune responses by sublingual administration of poly (lactic-co-glycolic) acid (PLGA)-encapsulated allergen in BALB/c mice.

    PubMed

    Salari, Farhad; Varasteh, Abdol-Reza; Vahedi, Fatemeh; Hashemi, Maryam; Sankian, Mojtaba

    2015-12-01

    The goal of this study was to investigate whether poly (lactic-co-glycolic) acid (PLGA) nanoparticles could enhance sublingual immunotherapy (SLIT) efficacy. BALB/c mice sensitized to rChe a 3 were treated sublingually either with soluble rChe a 3 (100μg/dose) or PLGA-encapsulated rChe a 3 (5, 25, or 50μg/dose). SLIT with PLGA-encapsulated rChe a 3 (equivalent to 25 and 50μg rChe a 3 per dose) led to significantly increased antigen-specific IgG2a, along with no effect on allergen-specific IgE and IgG1 antibody levels. In addition, interleukin 4 (IL-4) levels in restimulated splenocytes were significantly less, while interferon-γ (IFN-γ), interleukin-10 (IL-10), and transforming growth factor-β (TGF-β) levels, as well as Foxp3 expression, were significantly greater than in the control groups. Our findings suggest that PLGA nanoparticle-based vaccination may help rational development of sublingual immunotherapy through reduction of the needed allergen doses and also significantly enhanced systemic T regulatory (Treg) and T helper 1 (Th1) immune responses.

  8. Preparation of hydroxyapatite/poly(lactic acid) hybrid microparticles for local drug delivery

    NASA Astrophysics Data System (ADS)

    Loca, D.; Locs, J.; Berzina-Cimdina, L.

    2013-12-01

    Calcium phosphate (CaP) bioceramic is well known as bioactive and biocompatible material in bone tissue regeneration applications. Apatitic CaP, especially nano sized hydroxyapatite (NHAp), is more similar to the natural apatite presented in the bone tissue than CaP bioceramics. In the current research NHAp was modified using biodegradable polymer - poly(lactic acid) (PLA) to develop composites providing bone regeneration and local drug delivery. NHAp/PLA microcapsules were prepared using solid-in-water-in-oil-in-water (s/w1/o/w2) encapsulation technology. The impact of primary and secondary emulsion stability on the emulsion droplet and microparticle properties was evaluated. The stability of final emulsion can be increased by varying the process parameters. Stable s/w1/o/w2 emulsion using 3ml of NHAp suspension, not less than 100ml of 4% PVA water solution and 10ml of 10% PLA solution in dichloromethane can be obtained. S/w1/o/w2 microencapuslation method can be effectively used for the preparation of multi-domain microcapsules achieving high NHAp encapsulation efficacy (93%).

  9. Lectin-Conjugated Clarithromycin and Acetohydroxamic Acid-Loaded PLGA Nanoparticles: a Novel Approach for Effective Treatment of H. pylori.

    PubMed

    Jain, Sunil K; Haider, Tanweer; Kumar, Amrish; Jain, Akhlesh

    2016-10-01

    Helicobacter pylori infection remains challenging as it mainly colonized beneath the deep gastric mucosa and adheres to epithelial cells of the stomach. Concanavalin-A (Con-A)-conjugated gastro-retentive poly (lactic-co-glycolic acid) (PLGA) nanoparticles of acetohydroxamic acid (AHA) and clarithromycin (CLR) were prepared and evaluated under in vitro conditions. Solvent evaporation method was employed for preparation of nanoparticles and characterized for particle size distribution, surface morphology, percent drug entrapment, and in vitro drug release in simulated gastric fluid. Optimized nanoparticles were conjugated with Con-A and further characterized for Con-A conjugation efficiency and mucoadhesion and tested for in vitro anti-H. pylori activity. The conjugation with Con-A further sustained the drug release over a period of 8 h when compared to non-conjugated nanoparticles of AHA and CLR. In vitro anti H. pylori study confirmed that Con-A-conjugated nanoparticles containing both drugs, i.e., CLR and AHA, had shown maximum zone of inhibition compared to other formulations. In a nut shell, results suggest that the developed systems could be used for better therapeutic activity against H. pylori infection.

  10. Immune activity and biodistribution of polypeptide K237 and folic acid conjugated amphiphilic PEG-PLGA copolymer nanoparticles radiolabeled with 99mTc

    PubMed Central

    Wu, Yufeng; Huang, Xuanzhang; Chen, Jie; Xia, Junyong; Jiang, Hao; Ma, Jing; Wu, Jian

    2016-01-01

    In a previous study, amphiphilic copolymer, polypeptide K237 (HTMYYHHYQHHL) and folic acid (FA) modified poly(ethylene glycol)-poly(lactic-co-glycolic acid) (K237/FA-PEG-PLGA) nanoparticles were developed and studied as a drug carrier. To further promote the clinical application of K237/FA-PEG-PLGA nanoparticles and provide guidance for future research, we need to examine their specific biodistribution in vivo. In this study, K237/FA-PEG-PLGA nanoparticles were effectively labeled by a direct method with Technetium-99m (99mTc) using stannous chloride as a reducing agent. The optimal stability of the labeled nanoparticles was determined by evaluating their radiochemical purity in serum, physiological saline, diethylenetriaminepentaacetic acid (DTPA) and cysteine solutions. The affinity of ligands and receptors was elicited by cell binding and blocking experiments in KDR/folate receptor high expressing SKOV-3 ovarian cancer cells. The nanoparticles biodistribution was studied after intravenous administration in healthy mice xenografted with SKOV-3 cells. A higher percent injected dose per gram of tissue (% ID/g) was observed in liver, kidney, spleen, blood and tumor at 3 and 9 h post-injection. Scintigraphic images revealed that the radioactivity was mainly concentrated in tumor, liver, kidney and bladder; and in the heart, lung, and muscle was significantly lower at 3 h. The radioactivity distribution in the images is consistent with the in vivo biodistribution data. Our works demonstrated that K237/FA-PEG-PLGA nanoparticles have great potential as biodegradable drug carriers, especially for tumors expressing the folate and KDr receptor. PMID:27791199

  11. Tuning the degradation rate of calcium phosphate cements by incorporating mixtures of polylactic-co-glycolic acid microspheres and glucono-delta-lactone microparticles.

    PubMed

    Sariibrahimoglu, Kemal; An, Jie; van Oirschot, Bart A J A; Nijhuis, Arnold W G; Eman, Rhandy M; Alblas, Jacqueline; Wolke, Joop G C; van den Beucken, Jeroen J J P; Leeuwenburgh, Sander C G; Jansen, John A

    2014-11-01

    Calcium phosphate cements (CPCs) are frequently used as synthetic bone graft materials in view of their excellent osteocompatibility and clinical handling behavior. Hydroxyapatite-forming CPCs, however, degrade at very low rates, thereby limiting complete bone regeneration. The current study has investigated whether degradation of apatite-forming cements can be tuned by incorporating acid-producing slow-resorbing poly(D,L-lactic-co-glycolic) acid (PLGA) porogens, fast-resorbing glucono-delta-lactone (GDL) porogens, or mixtures thereof. The physicochemical, mechanical, and degradation characteristics of these CPC formulations were systematically analyzed upon soaking in phosphate-buffered saline (PBS). In parallel, various CPC formulations were implanted intramuscularly and orthotopically on top of the transverse process of goats followed by analysis of the soft tissue response and bone ingrowth after 12 weeks. In vitro degradation of GDL was almost completed after 2 weeks, as evidenced by characterization of the release of gluconic acid, while PLGA-containing CPCs released glycolic acid throughout the entire study (12 weeks), resulting in a decrease in compression strength of CPC. Extensive in vitro degradation of the CPC matrix was observed upon simultaneous incorporation of 30% PLGA-10% GDL. Histomorphometrical evaluation of the intramuscularly implanted samples revealed that all CPCs exhibited degradation, accompanied by an increase in capsule thickness. In the in vivo goat transverse process model, incorporation of 43% PLGA, 30% PLGA-5% GDL, and 30% PLGA-10% GDL in CPC significantly increased bone formation and resulted in higher bone height compared with both 10% GDL and 20% GDL-containing CPC samples.

  12. Formation of peptides from amino acids by single or multiple additions of ATP to suspensions of nucleoproteinoid microparticles

    NASA Technical Reports Server (NTRS)

    Nakashima, T.; Fox, S. W.

    1981-01-01

    The synthesis of peptides from individual amino acids or pairs of amino acids and ATP in the presence of catalysis by nucleoproteinoid microparticles is investigated. Experiments were performed with suspensions formed from the condensation of lysine-rich and acidic proteinoids with polyadenylic acid, to which were added glycine, phenylalanine, proline, lysine or glycine-phenylalanine mixtures, and ATP either at once or serially. Peptide yields are found to be greatest for equal amounts of acidic and basic proteinoids. The addition of imidazole is found to alter the preference of glycine-phenylalanine mixtures to form mixed heteropeptides rather than homopeptides. A rapid ATP decay in the peptide synthesis reaction is observed, and a greater yield is obtained for repeated small additions than for a single addition of ATP. The experimental system has properties similar to modern cells, and represents an organizational unit ready for the evolution of associated biochemical pathways.

  13. Laser irradiated fluorescent perfluorocarbon microparticles in 2-D and 3-D breast cancer cell models

    NASA Astrophysics Data System (ADS)

    Niu, Chengcheng; Wang, Long; Wang, Zhigang; Xu, Yan; Hu, Yihe; Peng, Qinghai

    2017-03-01

    Perfluorocarbon (PFC) droplets were studied as new generation ultrasound contrast agents via acoustic or optical droplet vaporization (ADV or ODV). Little is known about the ODV irradiated vaporization mechanisms of PFC-microparticle complexs and the stability of the new bubbles produced. In this study, fluorescent perfluorohexane (PFH) poly(lactic-co-glycolic acid) (PLGA) particles were used as a model to study the process of particle vaporization and bubble stability following excitation in two-dimensional (2-D) and three-dimensional (3-D) cell models. We observed localization of the fluorescent agent on the microparticle coating material initially and after vaporization under fluorescence microscopy. Furthermore, the stability and growth dynamics of the newly created bubbles were observed for 11 min following vaporization. The particles were co-cultured with 2-D cells to form 3-D spheroids and could be vaporized even when encapsulated within the spheroids via laser irradiation, which provides an effective basis for further work.

  14. Comparative evaluation of antibacterial activity of caffeic acid phenethyl ester and PLGA nanoparticle formulation by different methods

    NASA Astrophysics Data System (ADS)

    Arasoglu, Tülin; Derman, Serap; Mansuroglu, Banu

    2016-01-01

    The aim of the present study was to evaluate the antimicrobial activity of nanoparticle and free formulations of the CAPE compound using different methods and comparing the results in the literature for the first time. In parallel with this purpose, encapsulation of CAPE with the PLGA nanoparticle system (CAPE-PLGA-NPs) and characterization of nanoparticles were carried out. Afterwards, antimicrobial activity of free CAPE and CAPE-PLGA-NPs was determined using agar well diffusion, disk diffusion, broth microdilution and reduction percentage methods. P. aeroginosa, E. coli, S. aureus and methicillin-resistant S. aureus (MRSA) were chosen as model bacteria since they have different cell wall structures. CAPE-PLGA-NPs within the range of 214.0 ± 8.80 nm particle size and with an encapsulation efficiency of 91.59 ± 4.97% were prepared using the oil-in-water (o-w) single-emulsion solvent evaporation method. The microbiological results indicated that free CAPE did not have any antimicrobial activity in any of the applied methods whereas CAPE-PLGA-NPs had significant antimicrobial activity in both broth dilution and reduction percentage methods. CAPE-PLGA-NPs showed moderate antimicrobial activity against S. aureus and MRSA strains particularly in hourly measurements at 30.63 and 61.25 μg ml-1 concentrations (both p < 0.05), whereas they failed to show antimicrobial activity against Gram-negative bacteria (P. aeroginosa and E. coli, p > 0.05). In the reduction percentage method, in which the highest results of antimicrobial activity were obtained, it was observed that the antimicrobial effect on S. aureus was more long-standing (3 days) and higher in reduction percentage (over 90%). The appearance of antibacterial activity of CAPE-PLGA-NPs may be related to higher penetration into cells due to low solubility of free CAPE in the aqueous medium. Additionally, the biocompatible and biodegradable PLGA nanoparticles could be an alternative to solvents such as ethanol

  15. Comparative evaluation of antibacterial activity of caffeic acid phenethyl ester and PLGA nanoparticle formulation by different methods.

    PubMed

    Arasoglu, Tülin; Derman, Serap; Mansuroglu, Banu

    2016-01-15

    The aim of the present study was to evaluate the antimicrobial activity of nanoparticle and free formulations of the CAPE compound using different methods and comparing the results in the literature for the first time. In parallel with this purpose, encapsulation of CAPE with the PLGA nanoparticle system (CAPE-PLGA-NPs) and characterization of nanoparticles were carried out. Afterwards, antimicrobial activity of free CAPE and CAPE-PLGA-NPs was determined using agar well diffusion, disk diffusion, broth microdilution and reduction percentage methods. P. aeroginosa, E. coli, S. aureus and methicillin-resistant S. aureus (MRSA) were chosen as model bacteria since they have different cell wall structures. CAPE-PLGA-NPs within the range of 214.0 ± 8.80 nm particle size and with an encapsulation efficiency of 91.59 ± 4.97% were prepared using the oil-in-water (o-w) single-emulsion solvent evaporation method. The microbiological results indicated that free CAPE did not have any antimicrobial activity in any of the applied methods whereas CAPE-PLGA-NPs had significant antimicrobial activity in both broth dilution and reduction percentage methods. CAPE-PLGA-NPs showed moderate antimicrobial activity against S. aureus and MRSA strains particularly in hourly measurements at 30.63 and 61.25 μg ml(-1) concentrations (both p < 0.05), whereas they failed to show antimicrobial activity against Gram-negative bacteria (P. aeroginosa and E. coli, p > 0.05). In the reduction percentage method, in which the highest results of antimicrobial activity were obtained, it was observed that the antimicrobial effect on S. aureus was more long-standing (3 days) and higher in reduction percentage (over 90%). The appearance of antibacterial activity of CAPE-PLGA-NPs may be related to higher penetration into cells due to low solubility of free CAPE in the aqueous medium. Additionally, the biocompatible and biodegradable PLGA nanoparticles could be an alternative to solvents such as ethanol

  16. Suitability of polymer materials for production of pulmonary microparticles using a PGSS supercritical fluid technique: thermodynamic behaviour of fatty acids, PEGs and PEG-fatty acids.

    PubMed

    Vijayaraghavan, Meera; Stolnik, Snjezana; Howdle, Steven M; Illum, Lisbeth

    2012-11-15

    The thermodynamic behaviour of selected polymeric components for preparation of controlled release microparticles using supercritical carbon dioxide (scCO(2)) processing was investigated. The polymeric materials selected were egg lecithin (a model for the lung surfactant phospholipid), poly(ethyleneglycol) (PEG) of different molecular weights, fatty acids (C18, C16, and C14), and physical blends of PEGs and fatty acids. In addition a range of PEG-stearates was also assessed. Analysis of thermodynamic behaviour was performed by differential scanning calorimetry (DSC) and by assessment of their interaction with scCO(2) in a high-pressure variable volume view cell. The key criterion was to demonstrate a strong interaction with scCO(2) and to show liquefaction of the polymeric material at acceptable processing temperatures and pressures. Positive results should then indicate the suitability of these materials for processing by the Particle from Gas Saturated Solutions (PGSS) technique using scCO(2) to create microparticles for pulmonary administration. It was found that the materials tested interacted with scCO(2) and showed a sufficient lowering of their melting temperature (T(m)) to make them suitable for use in the PGSS microparticle production rig. Fatty acids of low T(m) were shown to act as a plasticising agent and to lower the T(m) of PEG further during interaction with scCO(2).

  17. Issues in long-term protein delivery using biodegradable microparticles.

    PubMed

    Ye, Mingli; Kim, Sungwon; Park, Kinam

    2010-09-01

    Recently, a variety of bioactive protein drugs have been available in large quantities as a result of advances in biotechnology. Such availability has prompted development of long-term protein delivery systems. Biodegradable microparticulate systems have been used widely for controlled release of protein drugs for days and months. The most widely used biodegradable polymer has been poly(d,l-lactic-co-glycolic acid) (PLGA). Protein-containing microparticles are usually prepared by the water/oil/water (W/O/W) double emulsion method, and variations of this method, such as solid/oil/water (S/O/W) and water/oil/oil (W/O/O), have also been used. Other methods of preparation include spray drying, ultrasonic atomization, and electrospray methods. The important factors in developing biodegradable microparticles for protein drug delivery are protein release profile (including burst release, duration of release, and extent of release), microparticle size, protein loading, encapsulation efficiency, and bioactivity of the released protein. Many studies used albumin as a model protein, and thus, the bioactivity of the release protein has not been examined. Other studies which utilized enzymes, insulin, erythropoietin, and growth factors have suggested that the right formulation to preserve bioactivity of the loaded protein drug during the processing and storage steps is important. The protein release profiles from various microparticle formulations can be classified into four distinct categories (Types A, B, C, and D). The categories are based on the magnitude of burst release, the extent of protein release, and the protein release kinetics followed by the burst release. The protein loading (i.e., the total amount of protein loaded divided by the total weight of microparticles) in various microparticles is 6.7+/-4.6%, and it ranges from 0.5% to 20.0%. Development of clinically successful long-term protein delivery systems based on biodegradable microparticles requires

  18. Incorporation of polymeric microparticles into collagen-hydroxyapatite scaffolds for the delivery of a pro-osteogenic peptide for bone tissue engineering

    NASA Astrophysics Data System (ADS)

    López-Noriega, Adolfo; Quinlan, Elaine; Celikkin, Nehar; O'Brien, Fergal J.

    2015-01-01

    Collagen-hydroxyapatite scaffolds are outstanding materials for bone tissue engineering as they are biocompatible, bioresorbable, osteoconductive, and osteoinductive. The objective of the present work was to assess the potential of increasing their regenerative capacity by functionalising the scaffolds for therapeutic delivery. This was achieved by the utilization of polymeric drug carriers. With this purpose, alginate, chitosan, gelatine, and poly(lactic-co-glycolic acid) (PLGA) microparticles eluting PTHrP 107-111, an osteogenic pentapeptide, were fabricated and tested by incorporating them into the scaffolds. Among them, PLGA microparticles show the most promising characteristics for use as drug delivery devices. Following the incorporation of the microparticles, the scaffolds maintained their interconnected porous structure and the mechanical properties of the materials were not adversely affected. In addition, the microparticles released all their PTHrP 107-111 cargo. Most importantly, the delivered peptide proved to be bioactive and promoted enhanced osteogenesis as assessed by alkaline phosphatase production and osteocalcin and osteopontin gene expression when pre-osteoblastic cells were seeded on the scaffolds. While the focus was on bone repair, the release system described in this study can be used for the delivery of therapeutics for healing and regeneration of a variety of tissue types depending on the type of collagen scaffold chosen.

  19. Development and characterization of sorafenib-loaded PLGA nanoparticles for the systemic treatment of liver fibrosis.

    PubMed

    Lin, Ts-Ting; Gao, Dong-Yu; Liu, Ya-Chi; Sung, Yun-Chieh; Wan, Dehui; Liu, Jia-Yu; Chiang, Tsaiyu; Wang, Liying; Chen, Yunching

    2016-01-10

    Sorafenib is a tyrosine kinase inhibitor that has recently been shown to be a potential antifibrotic agent. However, a narrow therapeutic window limits the clinical use and therapeutic efficacy of sorafenib. Herein, we have developed and optimized nanoparticle (NP) formulations prepared from a mixture of poly(ethylene glycol)-b-poly(lactic-co-glycolic acid) (PEG-PLGA) copolymers with poly(lactic-co-glycolic acid) (PLGA) for the systemic delivery of sorafenib into the fibrotic livers of CCl4-induced fibrosis mouse models. We characterized and compared the pharmaceutical and biological properties of two different PLGA nanoparticles (NPs)--PEG-PLGA NPs (PEG-PLGA/PLGA=10/0) and PEG-PLGA/PLGA NPs (PEG-PLGA/PLGA=5/5). Increasing the PLGA content in the PEG-PLGA/PLGA mixture led to increases in the particle size and drug encapsulation efficacy and a decrease in the drug release rate. Both PEG-PLGA and PEG-PLGA/PLGA NPs significantly prolonged the blood circulation of the cargo and increased the uptake by the fibrotic livers. The systemic administration of PEG-PLGA or PEG-PLGA/PLGA NPs containing sorafenib twice per week for a period of 4 weeks efficiently ameliorated liver fibrosis, as indicated by decreased α-smooth muscle actin (α-SMA) content and collagen production in the livers of CCl4-treated mice. Furthermore, sorafenib-loaded PLGA NPs significantly shrank the abnormal blood vessels and decreased microvascular density (MVD), leading to vessel normalization in the fibrotic livers. In conclusion, our results reflect the clinical potential of sorafenib-loaded PLGA NPs for the prevention and treatment of liver fibrosis.

  20. Surface Mechanical and Rheological Behaviors of Biocompatible Poly((D,L-lactic acid-ran-glycolic acid)-block-ethylene glycol) (PLGA-PEG) and Poly((D,L-lactic acid-ran-glycolic acid-ran-ε-caprolactone)-block-ethylene glycol) (PLGACL-PEG) Block Copolymers at the Air-Water Interface.

    PubMed

    Kim, Hyun Chang; Lee, Hoyoung; Khetan, Jawahar; Won, You-Yeon

    2015-12-29

    Air-water interfacial monolayers of poly((D,L-lactic acid-ran-glycolic acid)-block-ethylene glycol) (PLGA-PEG) exhibit an exponential increase in surface pressure under high monolayer compression. In order to understand the molecular origin of this behavior, a combined experimental and theoretical investigation (including surface pressure-area isotherm, X-ray reflectivity (XR) and interfacial rheological measurements, and a self-consistent field (SCF) theoretical analysis) was performed on air-water monolayers formed by a PLGA-PEG diblock copolymer and also by a nonglassy analogue of this diblock copolymer, poly((D,L-lactic acid-ran-glycolic acid-ran-caprolactone)-block-ethylene glycol) (PLGACL-PEG). The combined results of this study show that the two mechanisms, i.e., the glass transition of the collapsed PLGA film and the lateral repulsion of the PEG brush chains that occur simultaneously under lateral compression of the monolayer, are both responsible for the observed PLGA-PEG isotherm behavior. Upon cessation of compression, the high surface pressure of the PLGA-PEG monolayer typically relaxes over time with a stretched exponential decay, suggesting that in this diblock copolymer situation, the hydrophobic domain formed by the PLGA blocks undergoes glass transition in the high lateral compression state, analogously to the PLGA homopolymer monolayer. In the high PEG grafting density regime, the contribution of the PEG brush chains to the high monolayer surface pressure is significantly lower than what is predicted by the SCF model because of the many-body attraction among PEG segments (referred to in the literature as the "n-cluster" effects). The end-grafted PEG chains were found to be protein resistant even under the influence of the "n-cluster" effects.

  1. High-resolution direct 3D printed PLGA scaffolds: print and shrink.

    PubMed

    Chia, Helena N; Wu, Benjamin M

    2014-12-17

    Direct three-dimensional printing (3DP) produces the final part composed of the powder and binder used in fabrication. An advantage of direct 3DP is control over both the microarchitecture and macroarchitecture. Prints which use porogen incorporated in the powder result in high pore interconnectivity, uniform porosity, and defined pore size after leaching. The main limitations of direct 3DP for synthetic polymers are the use of organic solvents which can dissolve polymers used in most printheads and limited resolution due to unavoidable spreading of the binder droplet after contact with the powder. This study describes a materials processing strategy to eliminate the use of organic solvent during the printing process and to improve 3DP resolution by shrinking with a non-solvent plasticizer. Briefly, poly(lactic-co-glycolic acid) (PLGA) powder was prepared by emulsion solvent evaporation to form polymer microparticles. The printing powder was composed of polymer microparticles dry mixed with sucrose particles. After printing with a water-based liquid binder, the polymer microparticles were fused together to form a network by solvent vapor in an enclosed vessel. The sucrose is removed by leaching and the resulting scaffold is placed in a solution of methanol. The methanol acts as a non-solvent plasticizer and allows for polymer chain rearrangement and efficient packing of polymer chains. The resulting volumetric shrinkage is ∼80% at 90% methanol. A complex shape (honey-comb) was designed, printed, and shrunken to demonstrate isotropic shrinking with the ability to reach a final resolution of ∼400 μm. The effect of type of alcohol (i.e. methanol or ethanol), concentration of alcohol, and temperature on volumetric shrinking was studied. This study presents a novel materials processing strategy to overcome the main limitations of direct 3DP to produce high resolution PLGA scaffolds.

  2. Biodistribution of PLGA and PLGA/chitosan nanoparticles after repeat-dose oral delivery in F344 rats for 7 days

    PubMed Central

    Navarro, Sara M; Darensbourg, Caleb; Cross, Linda; Stout, Rhett; Coulon, Diana; Astete, Carlos E; Morgan, Timothy; Sabliov, Cristina M

    2015-01-01

    Aim To quantify in vivo the biodistribution of poly(lactic-co-glycolic) acid (PLGA) and PLGA/chitosan nanoparticles (PLGA/Chi NPs) and assess if the positive charge of chitosan significantly enhances nanoparticle absorption in the GI tract. Material & methods PLGA and PLGA/Chi NPs covalently linked to tetramethylrhodamine-5-isothiocyanate (TRITC) were orally administered to F344 rats for 7 days, and the biodistribution of fluorescent NPs was analyzed in different organs. Results The highest amount of particles (% total dose/g) was detected for both treatments in the spleen, followed by intestine and kidney, and then by liver, lung, heart and brain, with no significant difference between PLGA and PLGA/Chi NPs. Conclusion Only a small percentage of orally delivered NPs was detected in the analyzed organs. The positive charge conferred by chitosan was not sufficient to improve the absorption of the PLGA/Chi NPs over that of PLGA NPs. PMID:25491670

  3. Porous silicon oxide-PLGA composite microspheres for sustained ocular delivery of daunorubicin

    PubMed Central

    Nan, Kaihui; Ma, Feiyan; Hou, Huiyuan; Freeman, William R.; Sailor, Michael J.; Cheng, Lingyun

    2014-01-01

    A water-soluble anthracycline antibiotic drug (daunorubicin, DNR) was loaded into oxidized porous silicon (pSiO2) microparticles and then encapsulated with a layer of polymer (poly lactide-co-glycolide, PLGA) to investigate their synergistic effects in control of DNR release. Similarly fabricated PLGA-DNR microspheres without pSiO2, and pSiO2 microparticles without PLGA were used as control particles. The composite microparticles synthesized by a solid-in-oil-in-water (S/O/W) emulsion method have mean diameters of 52.33±16.37 μm for PLGA-pSiO2_21/40-DNR and the mean diameter of 49.31±8.87 μm for PLGA-pSiO2_6/20-DNR. The mean size, 26.00±8 μm, of PLGA-DNR was significantly smaller, compared with the other two (p<0.0001). Optical microscopy revealed that PLGA-pSiO2-DNR microsphere contained multiple pSiO2 particles. In vitro release experiments determined that control PLGA-DNR microspheres completely released DNR within 38 days and control pSiO2-DNR microparticles (with no PLGA coating) released DNR within 14 days, while the PLGA-pSiO2-DNR microspheres released DNR for 74 days. Temporal release profiles of DNR from PLGA-pSiO2 composite particles indicated that both PLGA and pSiO2 contribute to the sustained release of the payload. The PLGA-pSiO2 composite displayed a more constant rate of DNR release than the pSiO2 control formulation, and it displayed a significantly slower release of DNR than either the PLGA or pSiO2 formulations. We conclude that this system may be useful in managing unwanted ocular proliferation when formulated with anti-proliferation compounds such as DNR. PMID:24793657

  4. Thermal behavior and stability of biodegradable spray-dried microparticles containing triamcinolone.

    PubMed

    da Silva, Arnóbio Antônio; de Matos, Jivaldo Rosário; Formariz, Thalita Pedroni; Rossanezi, Gustavo; Scarpa, Maria Virginia; do Egito, Eryvaldo Sócrates Tabosa; de Oliveira, Anselmo Gomes

    2009-02-23

    Thermal analysis has been widely used for obtaining information about drug-polymer interactions and for pre-formulation studies of pharmaceutical dosage forms. In this work, biodegradable microparticles of poly (d,L-lactide-co-glycolide) (PLGA) containing triamcinolone (TR) in various drug:polymer ratios were produced by spray drying. The main purpose of this study was to study the effect of the spray-drying process not only on the drug-polymer interactions but also on the stability of microparticles using differential scanning calorimetry (DSC), thermogravimetry (TG) and derivative thermogravimetry (DTG), X-ray analysis (XRD), and infrared spectroscopy (IR). The evaluation of drug-polymer interactions and the pre-formulation studies were assessed using the DSC, TG and DTG, and IR. The quantitative analysis of drugs entrapped in PLGA microparticles was performed by the HPLC method. The results showed high levels of drug-loading efficiency for all used drug:polymer ratio, and the polymorph used for preparing the microparticles was the form B. The DSC and TG/DTG profiles for drug-loaded microparticles were very similar to those for the physical mixtures of the components. Therefore, a correlation between drug content and the structural and thermal properties of drug-loaded PLGA microparticles was established. These data indicate that the spray-drying technique does not affect the physico-chemical stability of the microparticle components. These results are in agreement with the IR analysis demonstrating that no significant chemical interaction occurs between TR and PLGA in both physical mixtures and microparticles. The results of the X-ray analysis are in agreement with the thermal analysis data showing that the amorphous form of TR prevails over a small fraction of crystalline phase of the drug also present in the TR-loaded microparticles. From the pre-formulation studies, we have found that the spray-drying methodology is an efficient process for obtaining TR

  5. Improving the encapsulation efficiency and sustained release behaviour of chitosan/β-lactoglobulin double-coated microparticles by palmitic acid grafting.

    PubMed

    Yang, Han-Joo; Lee, Pei Sia; Choe, Jaehyeog; Suh, Seokjin; Ko, Sanghoon

    2017-04-01

    Chitosan (CS) was grafted with 0.1 and 0.5% (w/v) palmitic acid (PA) to improve its encapsulation efficiency (EE) and sustained release characteristics when forming CS microparticles. Thereafter, PA-grafted CS (PA-CS) microparticles were coated with denatured β-lactoglobulin (βlg), which forms an outer protective layer. The possibility of hydrophobic interaction with the hydrophobic substances in the CS microparticles increased as the proportion of the grafted PA increased. EE was measured as 64.79, 83.72, and 85.00% for the non-grafted, 0.1, and 0.5% PA-CS microparticles, respectively. In simulated small intestinal conditions, 4.66 and 17.55% of the core material release in the PA-CS microparticles were sustained after 180min by 0.1, and 0.5% PA grafting, respectively. PA grafting enables the sustained release in simulated gastrointestinal fluids by enhancing the hydrophobic interaction between CS and the hydrophobic core material.

  6. Hemocompatibility of folic-acid-conjugated amphiphilic PEG-PLGA copolymer nanoparticles for co-delivery of cisplatin and paclitaxel: treatment effects for non-small-cell lung cancer.

    PubMed

    He, Zelai; Shi, Zengfang; Sun, Wenjie; Ma, Jing; Xia, Junyong; Zhang, Xiangyu; Chen, Wenjun; Huang, Jingwen

    2016-06-01

    In this study, we used folic-acid-modified poly(ethylene glycol)-poly(lactic-co-glycolic acid) (FA-PEG-PLGA) to encapsulate cisplatin and paclitaxel (separately or together), and evaluated their antitumor effects against lung cancer; this study was conducted in order to investigate the antitumor effects of the co-delivery of cisplatin and paclitaxel by a targeted drug delivery system. Blood compatibility assays and complement activation tests revealed that FA-PEG-PLGA nanoparticles did not induce blood hemolysis, blood clotting, or complement activation. The results also indicated that FA-PEG-PLGA nanoparticles had no biotoxic effects, the drug delivery system allowed controlled release of the cargo molecules, and the co-delivery of cisplatin and paclitaxel efficiently induces cancer cell apoptosis and cell cycle retardation. In addition, co-delivery of cisplatin and paclitaxel showed the ability to suppress xenograft lung cancer growth and prolong the survival time of xenografted mice. These results implied that FA-PEG-PLGA nanoparticles can function as effective carriers of cisplatin and paclitaxel, and that co-delivery of cisplatin and paclitaxel by FA-PEG-PLGA nanoparticles results in more effective antitumor effects than the combination of free-drugs or single-drug-loaded nanoparticles.

  7. Humidity-dependent compression-induced glass transition of the air–water interfacial Langmuir films of poly(D,L-lactic acid-ran-glycolic acid) (PLGA)

    SciTech Connect

    Kim, Hyun Chang; Lee, Hoyoung; Jung, Hyunjung; Choi, Yun -Hwa; Meron, Mati; Lin, Binhua; Bang, Joona; Won, You -Yeon

    2015-08-26

    Constant rate compression isotherms of the air–water interfacial Langmuir films of poly(D,L-lactic acid-ran-glycolic acid) (PLGA)show a distinct feature of an exponential increase in surface pressure in the high surface polymer concentration regime. We have previously demonstrated that this abrupt increase in surface pressure is linked to the glass transition of the polymer film, but the detailed mechanism of this process is not understood. In order to obtain a molecular-level understanding of this behavior, we performed extensive characterizations of the surface mechanical, structural and rheological properties of Langmuir PLGA films at the air–water interface, using combined experimental techniques including the Langmuir film balance, X-ray reflectivity and double-wall-ring interfacial rheometry methods.

  8. Biodegradable nanocomposite microparticles as drug delivering injectable cell scaffolds.

    PubMed

    Wen, Yanhong; Gallego, Monica Ramos; Nielsen, Lene Feldskov; Jorgensen, Lene; Everland, Hanne; Møller, Eva Horn; Nielsen, Hanne Mørck

    2011-11-30

    Injectable cell scaffolds play a dual role in tissue engineering by supporting cellular functions and delivering bioactive molecules. The present study aimed at developing biodegradable nanocomposite microparticles with sustained drug delivery properties thus potentially being suitable for autologous stem cell therapy. Semi-crystalline poly(l-lactide/dl-lactide) (PLDL70) and poly(l-lactide-co-glycolide) (PLGA85) were used to prepare nanoparticles by the double emulsion method. Uniform and spherical nanoparticles were obtained at an average size of 270-300 nm. The thrombin receptor activator peptide-6 (TRAP-6) was successfully loaded in PLDL70 and PLGA85 nanoparticles. During the 30 days' release, PLDL70 nanoparticles showed sustainable release with only 30% TRAP-6 released within the first 15 days, while almost 80% TRAP-6 was released from PLGA85 nanoparticles during the same time interval. The release mechanism was found to depend on the crystallinity and composition of the nanoparticles. Subsequently, mPEG-PLGA nanocomposite microparticles containing PLDL70 nanoparticles were produced by the ultrasonic atomization method and evaluated to successfully preserve the intrinsic particulate properties and the sustainable release profile, which was identical to that of the nanoparticles. Good cell adhesion of the human fibroblasts onto the nanocomposite microparticles was observed, indicating the desired cell biocompatibility. The presented results thus demonstrate the development of nanocomposite microparticles tailored for sustainable drug release for application as injectable cell scaffolds.

  9. Dry powders based on PLGA nanoparticles for pulmonary delivery of antibiotics: modulation of encapsulation efficiency, release rate and lung deposition pattern by hydrophilic polymers.

    PubMed

    Ungaro, Francesca; d'Angelo, Ivana; Coletta, Ciro; d'Emmanuele di Villa Bianca, Roberta; Sorrentino, Raffaella; Perfetto, Brunella; Tufano, Maria Antonietta; Miro, Agnese; La Rotonda, Maria Immacolata; Quaglia, Fabiana

    2012-01-10

    Although few experimental studies have been handled so far to exploit the potential of poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NPs) in the production of dry powders for antibiotic inhalation, there has been no comprehensive study on the role played by NP composition. In this work, we try to shed light on this aspect by designing and developing a pulmonary delivery system for antibiotics, such as tobramycin (Tb), based on PLGA NPs embedded in an inert microcarrier made of lactose, referred to as nano-embedded micro-particles (NEM). At nanosize level, helper hydrophilic polymers were used to impart the desired surface, bulk and release properties to PLGA NPs prepared by a modified emulsion-solvent diffusion technique. Results showed that poly(vinyl alcohol) (PVA) and chitosan (CS) are essential to optimise the size and modulate the surface properties of Tb-loaded PLGA NPs, whereas the use of alginate (Alg) allows efficient Tb entrapment within NPs and its release up to one month. Optimized formulations display good in vitro antimicrobial activity against P. aeruginosa planktonic cells. Furthermore, spray-drying of the NPs with lactose yielded NEM with peculiar but promising flow and aerosolization properties, while preserving the peculiar NP features. Nonetheless, in vivo biodistribution studies showed that PVA-modified Alg/PLGA NPs reached the deep lung, while CS-modified NPs were found in great amounts in the upper airways, lining lung epithelial surfaces. In conclusion, PLGA NP composition appears to play a crucial role in determining not only the technological features of NPs but, once processed in the form of NEM, also their in vitro/in vivo deposition pattern.

  10. Fabrication of uniform DNA-conjugated hydrogel microparticles via replica molding for facile nucleic acid hybridization assays.

    PubMed

    Lewis, Christina L; Choi, Chang-Hyung; Lin, Yan; Lee, Chang-Soo; Yi, Hyunmin

    2010-07-01

    We identify and investigate several critical parameters in the fabrication of single-stranded DNA conjugated poly(ethylene glycol) (PEG) microparticles based on replica molding (RM) for highly uniform and robust nucleic acid hybridization assays. The effects of PEG-diacrylate, probe DNA, and photoinitiator concentrations on the overall fluorescence and target DNA penetration depth upon hybridization are examined. Fluorescence and confocal microscopy results illustrate high conjugation capacity of the probe and target DNA, femtomole sensitivity, and sequence specificity. Combined, these findings demonstrate a significant step toward simple, robust, and scalable procedures to manufacture highly uniform and high-capacity hybridization assay particles in a well-controlled manner by exploiting many advantages that the batch processing-based RM technique offers. We envision that the results presented here may be readily applied to rapid and high-throughput hybridization assays for a wide variety of applications in bioprocess monitoring, food safety, and biological threat detection.

  11. A Stability-Indicating HPLC-DAD Method for Determination of Ferulic Acid into Microparticles: Development, Validation, Forced Degradation, and Encapsulation Efficiency

    PubMed Central

    Toledo, Maria da Graça; Pupo, Yasmine Mendes; Padilha de Paula, Josiane; Zanin, Sandra Maria Warumby

    2015-01-01

    A simple stability-indicating HPLC-DAD method was validated for the determination of ferulic acid (FA) in polymeric microparticles. Chromatographic conditions consisted of a RP C18 column (250 mm × 4.60 mm, 5 μm, 110 Å) using a mixture of methanol and water pH 3.0 (48 : 52 v/v) as mobile phase at a flow rate of 1.0 mL/min with UV detection at 320 nm. The developed method was validated as per ICH guidelines with respect to specificity, linearity, limit of quantification, limit of detection, accuracy, precision, and robustness provided suitable results regarding all parameters investigated. The calibration curve was linear in the concentration range of 10.0–70.0 μg/mL with a correlation coefficient >0.999. Precision (intraday and interday) was demonstrated by a relative standard deviation lower than 2.0%. Accuracy was assessed by the recovery test of FA from polymeric microparticles (99.02% to 100.73%). Specificity showed no interference from the components of polymeric microparticles or from the degradation products derived from acidic, basic, and photolytic conditions. In conclusion, the method is suitable to be applied to assay FA as bulk drug and into polymeric microparticles and can be used for studying its stability and degradation kinetics. PMID:26075139

  12. A Stability-Indicating HPLC-DAD Method for Determination of Ferulic Acid into Microparticles: Development, Validation, Forced Degradation, and Encapsulation Efficiency.

    PubMed

    Nadal, Jessica Mendes; Toledo, Maria da Graça; Pupo, Yasmine Mendes; Padilha de Paula, Josiane; Farago, Paulo Vitor; Zanin, Sandra Maria Warumby

    2015-01-01

    A simple stability-indicating HPLC-DAD method was validated for the determination of ferulic acid (FA) in polymeric microparticles. Chromatographic conditions consisted of a RP C18 column (250 mm × 4.60 mm, 5 μm, 110 Å) using a mixture of methanol and water pH 3.0 (48 : 52 v/v) as mobile phase at a flow rate of 1.0 mL/min with UV detection at 320 nm. The developed method was validated as per ICH guidelines with respect to specificity, linearity, limit of quantification, limit of detection, accuracy, precision, and robustness provided suitable results regarding all parameters investigated. The calibration curve was linear in the concentration range of 10.0-70.0 μg/mL with a correlation coefficient >0.999. Precision (intraday and interday) was demonstrated by a relative standard deviation lower than 2.0%. Accuracy was assessed by the recovery test of FA from polymeric microparticles (99.02% to 100.73%). Specificity showed no interference from the components of polymeric microparticles or from the degradation products derived from acidic, basic, and photolytic conditions. In conclusion, the method is suitable to be applied to assay FA as bulk drug and into polymeric microparticles and can be used for studying its stability and degradation kinetics.

  13. PLGA/alginate composite microspheres for hydrophilic protein delivery.

    PubMed

    Zhai, Peng; Chen, X B; Schreyer, David J

    2015-11-01

    Poly(lactic-co-glycolic acid) (PLGA) microspheres and PLGA/alginate composite microspheres were prepared by a novel double emulsion and solvent evaporation technique and loaded with bovine serum albumin (BSA) or rabbit anti-laminin antibody protein. The addition of alginate and the use of a surfactant during microsphere preparation increased the encapsulation efficiency and reduced the initial burst release of hydrophilic BSA. Confocal laser scanning microcopy (CLSM) of BSA-loaded PLGA/alginate composite microspheres showed that PLGA, alginate, and BSA were distributed throughout the depths of microspheres; no core/shell structure was observed. Scanning electron microscopy revealed that PLGA microspheres erode and degrade more quickly than PLGA/alginate composite microspheres. When loaded with anti-laminin antibody, the function of released antibody was well preserved in both PLGA and PLGA/alginate composite microspheres. The biocompatibility of PLGA and PLGA/alginate microspheres were examined using four types of cultured cell lines, representing different tissue types. Cell survival was variably affected by the inclusion of alginate in composite microspheres, possibly due to the sensitivity of different cell types to excess calcium that may be released from the calcium cross-linked alginate.

  14. Poly(lactic acid) microparticles coated with insulin-containing layer-by-layer films and their pH-dependent insulin release.

    PubMed

    Hashide, Ryosuke; Yoshida, Kentaro; Hasebe, Yasushi; Seno, Masaru; Takahashi, Shigehiro; Sato, Katsuhiko; Anzai, Jun-Ichi

    2014-04-01

    Poly(lactic acid) (PLA) microparticles were coated with layer-by-layer (LbL) films containing insulin and the pH-dependent release of insulin was studied. The LbL films were prepared on the surface of PLA microparticles by the alternate deposition of insulin and poly(allylamine hydrochloride) (PAH) through the electrostatic attraction between insulin and PAH. The insulin loading on the PLA microparticles depended on the film thickness, which corresponded to the number of insulin layers, and on the pH of the solution used to deposit insulin. The insulin loading increased with the film thickness and when the film was prepared at pH 7.4. The LbL films decomposed upon exposure to acidic solutions because the electrostatic attraction between the insulin and the PAH in the films disappeared when the charge on insulin changed from negative to positive at an acidic pH, which resulted in the release of insulin. The temperature and salt concentration did not affect the pH stability of the LbL films. The pH threshold for insulin release was pH 5.0-6.0, which corresponds to isoelectric point of insulin, 5.4. The release of insulin from the microparticles was rapid, and was almost complete within a few minutes. The circular dichroism spectra showed that the released insulin retained its original secondary structure. Our insulin-loaded PLA microparticles may be useful for the controlled release of insulin.

  15. Microparticles Produced by the Hydrogel Template Method for Sustained Drug Delivery

    PubMed Central

    Lu, Ying; Sturek, Michael; Park, Kinam

    2014-01-01

    Polymeric microparticles have been used widely for sustained drug delivery. Current methods of microparticle production can be improved by making homogeneous particles in size and shape, increasing the drug loading, and controlling the initial burst release. In the current study, the hydrogel template method was used to produce homogeneous poly(lactide-co-glycolide) (PLGA) microparticles and to examine formulation and process-related parameters. Poly(vinyl alcohol) (PVA) was used to make hydrogel templates. The parameters examined include PVA molecular weight, type of PLGA (as characterized by lactide content, inherent viscosity), polymer concentration, drug concentration and composition of solvent system. Three model compounds studied were risperidone, methylprednisolone acetate and paclitaxel. The ability of the hydrogel template method to produce microparticles with good conformity to template was dependent on molecular weight of PVA and viscosity of the PLGA solution. Drug loading and encapsulation efficiency were found to be influenced by PLGA lactide content, polymer concentration and composition of the solvent system. The drug loading and encapsulation efficiency were 28.7% and 82% for risperidone, 31.5% and 90% for methylprednisolone acetate, and 32.2 % and 92 % for paclitaxel, respectively. For all three drugs, release was sustained for weeks, and the in vitro release profile of risperidone was comparable to that of microparticles prepared using the conventional emulsion method. The hydrogel template method provides a new approach of manipulating microparticles. PMID:24333903

  16. Effects of transforming growth factor beta1 released from biodegradable polymer microparticles on marrow stromal osteoblasts cultured on poly(propylene fumarate) substrates.

    PubMed

    Peter, S J; Lu, L; Kim, D J; Stamatas, G N; Miller, M J; Yaszemski, M J; Mikos, A G

    2000-06-05

    Recombinant human transforming growth factor beta1 (TGF-beta1) was incorporated into microparticles of blends of poly(DL-lactic-co-glycolic acid) (PLGA) and poly(ethylene glycol) (PEG) to create a delivery vehicle for the growth factor. The entrapment efficiency of TGF-beta1 in the microparticles containing 5% PEG was 40.3 +/- 1.2% for a TGF-beta1 loading density of 6.0 ng/1 mg of microparticles. For the same loading, 17.9 +/- 0.6 and 32.1 +/- 2.5% of the loaded TGF-beta1 was released after 1 and 8 days, respectively, followed by a plateau for the remaining 3 weeks. Rat marrow stromal cells showed a dose response to TGF-beta1 released from the microparticles similar to that of added TGF-beta1, indicating the activity of TGF-beta1 was retained during microparticle fabrication and after TGF-beta1 release. An optimal TGF-beta1 dosage of 1.0 ng/mL was determined through a 3-day dose response study for maximal alkaline phosphatase (ALP) activity. The TGF-beta1 released from the microparticles loaded with 6.0 ng TGF-beta1/1 mg of microparticles for the optimal dosage of TGF-beta1 enhanced the proliferation and osteoblastic differentiation of marrow stromal cells cultured on poly(propylene fumarate) substrates. The cells showed significantly increased total cell number, ALP activity, and osteocalcin production with values reaching 138,700 +/- 3300 cells/cm(2), 22.8 +/- 1.5 x 10(-7) micromol/min/cell, and 15.9 +/- 1.5 x 10(-6) ng/cell, respectively, after 21 days as compared to cells cultured under control conditions without TGF-beta1. These results suggest that controlled release of TGF-beta1 from the PLGA/PEG blend microparticles may find applications in modulating cellular response during bone healing at a skeletal defect site.

  17. Lead sulfate nano- and microparticles in the acid plant blow-down generated at the sulfuric acid plant of the El Teniente mine, Chile.

    PubMed

    Barassi, Giancarlo M; Klimsa, Martin; Borrmann, Thomas; Cairns, Mathew J; Kinkel, Joachim; Valenzuela, Fernando

    2014-12-01

    The acid plant 'blow-down' (also called weak acid) produced at El Teniente mine in Chile was characterized. This liquid waste (tailing) is generated during the cooling and cleaning of the smelter gas prior to the production of sulfuric acid. The weak acid was composed of a liquid and a solid phase (suspended solids). The liquid phase of the sample analyzed in this study mainly contained Cu (562 mg L(-1)), SO4(2-) (32 800 mg L(-1)), Ca (1449 mg L(-1)), Fe (185 mg L(-1)), As (6 mg L(-1)), K (467 mg L(-1)) and Al (113 mg L(-1)). Additionally, the sample had a pH-value and total acidity of 0.45 and 2970 mg L(-1) as CaCO3, respectively. Hence, this waste was classified as extremely acidic and with a high metal content following the Ficklin diagram classification. Elemental analysis using atomic absorption, inductively coupled plasma, X-ray diffraction and electron microscopy showed that the suspended solids were anglesite (PbSO4) nano- and microparticles ranging from 50 nm to 500 nm in diameter.

  18. PEG-b-PLA micelles and PLGA-b-PEG-b-PLGA sol-gels for drug delivery.

    PubMed

    Cho, Hyunah; Gao, Jieming; Kwon, Glen S

    2016-10-28

    Poly(ethylene glycol)-block-poly(D,L-lactic acid) (PEG-b-PLA) micelles and poly(D,L-lactic-co-glycolic acid)-block-polyethylene glycol)-block-poly(D,L-lactic-co-glycolic acid) (PLGA-b-PEG-b-PLGA) sol-gels have been extensively researched for systemic and localized drug delivery applications, respectively, and they have both progressed into humans for paclitaxel, an important yet poorly water-soluble chemotherapeutic agent. In this review article, preclinical and clinical research on PEG-b-PLA micelles and PLGA-b-PEG-b-PLGA sol-gels that has focused on paclitaxel will be updated, and recent research on other poorly water-soluble anticancer agents and delivery of drug combinations (i.e. multi-drug delivery) that seeks synergistic anticancer efficacy will be summarized. PEG-b-PLA micelles are a first-generation platform for the systemic multi-delivery of poorly water soluble anticancer agents. PLGA-b-PEG-b-PLGA sol-gels are a first-generation platform for the localized multi-drug delivery of water-soluble and/or poorly water-soluble anticancer agents. In summary, PEG-b-PLA micelles and PLGA-b-PEG-b-PLGA sol-gels may safely enable pre-clinical evaluation and clinical translation of poorly water-soluble anticancer agents, especially for promising, rapidly emerging anticancer combinations.

  19. An Aluminum Microfluidic Chip Fabrication Using a Convenient Micromilling Process for Fluorescent Poly(dl-lactide-co-glycolide) Microparticle Generation

    PubMed Central

    Lin, Yung-Sheng; Yang, Chih-Hui; Wang, Chih-Yu; Chang, Fang-Rong; Huang, Keng-Shiang; Hsieh, Wan-Chen

    2012-01-01

    This study presents the development of a robust aluminum-based microfluidic chip fabricated by conventional mechanical micromachining (computer numerical control-based micro-milling process). It applied the aluminum-based microfluidic chip to form poly(lactic-co-glycolic acid) (PLGA) microparticles encapsulating CdSe/ZnS quantum dots (QDs). A cross-flow design and flow-focusing system were employed to control the oil-in-water (o/w) emulsification to ensure the generation of uniformly-sized droplets. The size of the droplets could be tuned by adjusting the flow rates of the water and oil phases. The proposed microfluidic platform is easy to fabricate, set up, organize as well as program, and is valuable for further applications under harsh reaction conditions (high temperature and/or strong organic solvent systems). The proposed method has the advantages of actively controlling the droplet diameter, with a narrow size distribution, good sphericity, as well as being a simple process with a high throughput. In addition to the fluorescent PLGA microparticles in this study, this approach can also be applied to many applications in the pharmaceutical and biomedical area. PMID:22438719

  20. Tailoring magnetic PLGA nanoparticles suitable for doxorubicin delivery

    NASA Astrophysics Data System (ADS)

    Tansık, Gülistan; Yakar, Arzu; Gündüz, Ufuk

    2014-01-01

    One of the main problems of current cancer chemotherapy is the lack of selectivity of anti-cancer drugs to tumor cells, which leads to systemic toxicity and adverse side effects. In order to overcome these limitations, researches on controlled drug delivery systems have gained much attention. Nanoscale-based drug delivery systems provide tumor targeting. Among many types of nanocarriers, superparamagnetic nanoparticles with their biocompatible polymer coatings can be targeted to an intented site by an external magnetic field. Thus, the drug can be carried to the targeted site safely. The aim of this study is to prepare poly( dl-lactic- co-glycolic acid) (PLGA)-coated magnetic nanoparticles and load anti-cancer drug, doxorubicin to them. For this purpose, magnetite (Fe3O4) iron oxide nanoparticles were synthesized as a magnetic core material (MNP) and then coated with oleic acid. Oleic acid-coated MNP (OA-MNP) was encapsulated into PLGA. Effects of different OA-MNP/PLGA ratios on magnetite entrapment efficiency were investigated. Doxorubicin-loaded magnetic polymeric nanoparticles (DOX-PLGA-MNP) were prepared. After the characterization of prepared nanoparticles, their cytotoxic effects on MCF-7 cell line were studied. PLGA-coated magnetic nanoparticles (PLGA-MNP) had a proper size and superparamagnetic character. The highest magnetite entrapment efficiency of PLGA-MNP was estimated as 63 % at 1:8 ratio. Cytotoxicity studies of PLGA-MNP did not indicate any notable cell death between the concentration ranges of 2 and 125 μg/ml. Drug loading efficiency was estimated as 32 %, and it was observed that DOX-PLGA-MNP showed significant cytotoxicity on MCF-7 cells compared to PLGA-MNP. The results showed that prepared nanoparticles have desired size and superparamagnetic characteristics without serious toxic effects on cells. These nanoparticles may be suitable for targeted drug delivery applications.

  1. Mesenchymal stem cells attenuated PLGA-induced inflammatory responses by inhibiting host DC maturation and function.

    PubMed

    Zhu, Heng; Yang, Fei; Tang, Bo; Li, Xi-Mei; Chu, Ya-Nan; Liu, Yuan-Lin; Wang, Shen-Guo; Wu, De-Cheng; Zhang, Yi

    2015-01-01

    The poly lactic-co-glycolic acid (PLGA) bio-scaffold is a biodegradable scaffold commonly used for tissue repair. However, implanted PLGA scaffolds usually cause serious inflammatory responses around grafts. To improve PLGA scaffold-based tissue repair, it is important to control the PLGA-mediated inflammatory responses. Recent evidence indicated that PLGA induce dendritic cell (DC) maturation in vitro, which may initiate host immune responses. In the present study, we explored the modulatory effects of mesenchymal stem cells (MSC) on PLGA-induced DCs (PLGA-DC). We found that mouse MSCs inhibited PLGA-DC dendrite formation, as well as co-stimulatory molecule and pro-inflammatory factor expression. Functionally, MSC-educated PLGA-DCs promoted Th2 and regulatory T cell differentiation but suppressed Th1 and Th17 cell differentiation. Mechanistically, we determined that PLGA elicited DC maturation via inducing phosphorylation of p38/MAPK and ERK/MAPK pathway proteins in DCs. Moreover, MSCs suppressed PLGA-DCs by partially inactivating those pathways. Most importantly, we found that the MSCs were capable of suppressing DC maturation and immune function in vivo. Also, the proportion of mature DCs in the mice that received MSC-PLGA constructs greatly decreased compared with that of their PLGA-film implantation counterparts. Additionally, MSCs co-delivery increased regulatory T and Th2 cells but decreased the Th1 and Th17 cell numbers in the host spleens. Histological analysis showed that MSCs alleviated the inflammatory responses around the grafted PLGA scaffolds. In summary, our findings reveal a novel function for MSCs in suppressing PLGA-induced host inflammatory response and suggest that DCs are a new cellular target in improving PLGA scaffold-based tissue repair.

  2. An HPLC method for microanalysis and pharmacokinetics of marine sulfated polysaccharide PSS-loaded poly lactic-co-glycolic acid (PLGA) nanoparticles in rat plasma.

    PubMed

    Li, Peng-Li; Li, Chun-Xia; Xue, Yi-Ting; Li, Hai-Hua; Liu, Hong-Bing; He, Xiao-Xi; Yu, Guang-Li; Guan, Hua-Shi

    2013-04-02

    This study was aimed at developing a sensitive and selective HPLC method with postcolumn fluorescence derivatization for the detection of propylene glycol alginate sodium sulfate (PSS) in rat plasma. Plasma samples were prepared by a simple and fast ultrafiltration method. PSS was extracted from rat plasma with D-glucuronic acid as internal standard. Isocratic chromatographic separation was performed on a TSKgel G2500 PWxL column with the mobile phase of 0.1 M sodium sulfate at a flow rate of 0.5 mL/min. Analyte detection was achieved by fluorescence detection (FLD) at 250 nm (excitation) and 435 nm (emission) using guanidine hydrochloride as postcolumn derivatizing reagent in an alkaline medium at 120 °C. The calibration curve was linear over a concentration range of 1-500 μg/mL, and the lower limit of detection (LLOD) was found to be 250 ng/mL. This validated method was applied successfully to the pharmacokinetic study of PSS and PSS-loaded poly lactic-co-glycolic acid (PLGA) nanoparticles (PSS-NP) in rat plasma after a single intravenous (PSS only) and oral administration (PSS and PSS-NP). Significant differences in the main pharmacokinetic parameters of PSS and PSS-NP were observed. The relative bioavailability of PSS-NP was 190.10% compared with PSS which shows that PSS-NP can improve oral bioavailability.

  3. An HPLC Method for Microanalysis and Pharmacokinetics of Marine Sulfated Polysaccharide PSS-Loaded Poly Lactic-co-Glycolic Acid (PLGA) Nanoparticles in Rat Plasma

    PubMed Central

    Li, Peng-Li; Li, Chun-Xia; Xue, Yi-Ting; Li, Hai-Hua; Liu, Hong-Bing; He, Xiao-Xi; Yu, Guang-Li; Guan, Hua-Shi

    2013-01-01

    This study was aimed at developing a sensitive and selective HPLC method with postcolumn fluorescence derivatization for the detection of propylene glycol alginate sodium sulfate (PSS) in rat plasma. Plasma samples were prepared by a simple and fast ultrafiltration method. PSS was extracted from rat plasma with d-glucuronic acid as internal standard. Isocratic chromatographic separation was performed on a TSKgel G2500 PWxL column with the mobile phase of 0.1 M sodium sulfate at a flow rate of 0.5 mL/min. Analyte detection was achieved by fluorescence detection (FLD) at 250 nm (excitation) and 435 nm (emission) using guanidine hydrochloride as postcolumn derivatizing reagent in an alkaline medium at 120 °C. The calibration curve was linear over a concentration range of 1–500 μg/mL, and the lower limit of detection (LLOD) was found to be 250 ng/mL. This validated method was applied successfully to the pharmacokinetic study of PSS and PSS-loaded poly lactic-co-glycolic acid (PLGA) nanoparticles (PSS-NP) in rat plasma after a single intravenous (PSS only) and oral administration (PSS and PSS-NP). Significant differences in the main pharmacokinetic parameters of PSS and PSS-NP were observed. The relative bioavailability of PSS-NP was 190.10% compared with PSS which shows that PSS-NP can improve oral bioavailability. PMID:23549283

  4. Co-delivery of cisplatin and paclitaxel by folic acid conjugated amphiphilic PEG-PLGA copolymer nanoparticles for the treatment of non-small lung cancer

    PubMed Central

    He, Zelai; Huang, Jingwen; Xu, Yuanyuan; Zhang, Xiangyu; Teng, Yanwei; Huang, Can; Wu, Yufeng; Zhang, Xi; Zhang, Huijun; Sun, Wenjie

    2015-01-01

    An amphiphilic copolymer, folic acid (FA) modified poly(ethylene glycol)-poly(lactic-co-glycolic acid) (FA-PEG-PLGA) was prepared and explored as a nanometer carrier for the co-delivery of cisplatin (cis-diaminodichloroplatinum, CDDP) and paclitaxel (PTX). CDDP and PTX were encapsulated inside the hydrophobic inner core and chelated to the middle shell, respectively. PEG provided the outer corona for prolonged circulation. An in vitro release profile of the CDDP + PTX-encapsulated nanoparticles revealed that the PTX chelation cross-link prevented an initial burst release of CDDP. After an incubation period of 24 hours, the CDDP+PTX-encapsulated nanoparticles exhibited a highly synergistic effect for the inhibition of A549 (FA receptor negative) and M109 (FA receptor positive) lung cancer cell line proliferation. Pharmacokinetic experiment and distribution research shows that nanoparticles have longer circulation time in the blood and can prolong the treatment times of chemotherapeutic drugs. For the in vivo treatment of A549 cells xeno-graft lung tumor, the CDDP+PTX-encapsulated nanoparticles displayed an obvious tumor inhibiting effect with an 89.96% tumor suppression rate (TSR). This TSR was significantly higher than that of free chemotherapy drug combination or nanoparticles with a single drug. For M109 cells xeno-graft tumor, the TSR was 95.03%. In vitro and in vivo experiments have all shown that the CDDP+PTX-encapsulated nanoparticles have better targeting and antitumor effects in M109 cells than CDDP+PTX-loaded PEG-PLGA nanoparticles (p < 0.05). In addition, more importantly, the enhanced anti-tumor efficacy of the CDDP+PTX-encapsulated nanoparticles came with reduced side-effects. No obvious body weight loss or functional changes occurred within blood components, liver, or kidneys during the treatment of A549 and M109 tumor-bearing mice with the CDDP+PTX-encapsulated nanoparticles. Thus, the FA modified amphiphilic copolymer-based combination of CDDP and

  5. Hyaluronic acid-decorated dual responsive nanoparticles of Pluronic F127, PLGA, and chitosan for targeted co-delivery of doxorubicin and irinotecan to eliminate cancer stem-like cells

    PubMed Central

    Wang, Hai; Agarwal, Pranay; Zhao, Shuting; Xu, Ronald X.; Yu, Jianhua; Lu, Xiongbin; He, Xiaoming

    2016-01-01

    Dual responsive nanoparticles are developed for co-delivery of multiple anticancer drugs to target the drug resistance mechanisms of cancer stem-like cells (CSCs). The nanoparticles consist of four polymers approved by the Food and Drug Administration (FDA) for medical use: Poly(D,L-lactide-co-glycolide) (PLGA), Pluronic F127 (PF127), chitosan, and hyaluronic acid (HA). By combining PLGA and PF127 together, more stable and uniform-sized nanoparticles can be obtained than using PLGA or PF127 alone. The HA is used for not only actively targeting CSCs to reduce their drug resistance due to dormancy (i.e., slow metabolism), but also replacing the commonly used poly(vinyl alcohol) as a stabilizing agent to synthesize the nanoparticles using the double-emulsion approach and to allow for acidic pH-triggered drug release and thermal responsiveness. Besides minimizing drug efflux from CSCs, the nanoparticles encapsulated with doxorubicin hydrochloride (DOX, hydrophilic) and irinotecan (CPT, hydrophobic) to inhibit the activity of topoisomerases II and I, respectively, can fight against the CSC drug resistance associated with their enhanced DNA repair and anti-apoptosis. Ultimately, the two drugs-laden nanoparticles can be used to efficiently destroy the CSCs both in vitro and in vivo with up to ~500 times of enhancement compared to the simple mixture of the two drugs. PMID:26344365

  6. PEGylated apoptotic protein-loaded PLGA microspheres for cancer therapy

    PubMed Central

    Byeon, Hyeong Jun; Kim, Insoo; Choi, Ji Su; Lee, Eun Seong; Shin, Beom Soo; Youn, Yu Seok

    2015-01-01

    The aim of the current study was to investigate the antitumor potential of poly (D,L-lactic-co-glycolic acid) microspheres (PLGA MSs) containing polyethylene glycol (PEG)-conjugated (PEGylated) tumor necrosis factor–related apoptosis-inducing ligand (PEG-TRAIL). PEG-TRAIL PLGA MSs were prepared by using a water-in-oil-in-water double-emulsion method, and the apoptotic activities of supernatants released from the PLGA MSs at days 1, 3, and 7 were examined. The antitumor effect caused by PEG-TRAIL PLGA MSs was evaluated in pancreatic Mia Paca-2 cell-xenografted mice. PEG-TRAIL PLGA MS was found to be spherical and 14.4±1.06 μm in size, and its encapsulation efficiency was significantly greater than that of TRAIL MS (85.7%±4.1% vs 43.3%±10.9%, respectively). The PLGA MS gradually released PEG-TRAIL for 14 days, and the released PEG-TRAIL was shown to have clear apoptotic activity in Mia Paca-2 cells, whereas TRAIL released after 1 day had a negligible activity. Finally, PEG-TRAIL PLGA MS displayed remarkably greater antitumor efficacy than blank or TRAIL PLGA MS in Mia Paca-2 cell-xenografted mice in terms of tumor volume and weight, apparently due to increased stability and well-retained apoptotic activity of PEG-TRAIL in PLGA MS. We believe that this PLGA MS system, combined with PEG-TRAIL, should be considered a promising candidate for treating pancreatic cancer. PMID:25632232

  7. PEGylated apoptotic protein-loaded PLGA microspheres for cancer therapy.

    PubMed

    Byeon, Hyeong Jun; Kim, Insoo; Choi, Ji Su; Lee, Eun Seong; Shin, Beom Soo; Youn, Yu Seok

    2015-01-01

    The aim of the current study was to investigate the antitumor potential of poly (D,L-lactic-co-glycolic acid) microspheres (PLGA MSs) containing polyethylene glycol (PEG)-conjugated (PEGylated) tumor necrosis factor-related apoptosis-inducing ligand (PEG-TRAIL). PEG-TRAIL PLGA MSs were prepared by using a water-in-oil-in-water double-emulsion method, and the apoptotic activities of supernatants released from the PLGA MSs at days 1, 3, and 7 were examined. The antitumor effect caused by PEG-TRAIL PLGA MSs was evaluated in pancreatic Mia Paca-2 cell-xenografted mice. PEG-TRAIL PLGA MS was found to be spherical and 14.4±1.06 μm in size, and its encapsulation efficiency was significantly greater than that of TRAIL MS (85.7%±4.1% vs 43.3%±10.9%, respectively). The PLGA MS gradually released PEG-TRAIL for 14 days, and the released PEG-TRAIL was shown to have clear apoptotic activity in Mia Paca-2 cells, whereas TRAIL released after 1 day had a negligible activity. Finally, PEG-TRAIL PLGA MS displayed remarkably greater antitumor efficacy than blank or TRAIL PLGA MS in Mia Paca-2 cell-xenografted mice in terms of tumor volume and weight, apparently due to increased stability and well-retained apoptotic activity of PEG-TRAIL in PLGA MS. We believe that this PLGA MS system, combined with PEG-TRAIL, should be considered a promising candidate for treating pancreatic cancer.

  8. Radiolabeling of Poly(lactic-co-glycolic acid) (PLGA) Nanoparticles with Biotinylated F-18 Prosthetic Groups and Imaging of Their Delivery to the Brain with Positron Emission Tomography

    PubMed Central

    2015-01-01

    The avidin–biotin interaction permits rapid and nearly irreversible noncovalent linkage between biotinylated molecules and avidin-modified substrates. We designed a biotinylated radioligand intended for use in the detection of avidin-modified polymer nanoparticles in tissue with positron emission tomography (PET). Using an F-18 labeled prosthetic group, [18F]4-fluorobenzylamine, and a commercially available biotin derivate, NHS-PEG4-biotin, [18F]-fluorobenzylamide-poly(ethylene glycol)4-biotin ([18F]NPB4) was prepared with high purity and specific activity. The attachment of the [18F]NPB4 radioligand to avidin-modified poly(lactic-co-glycolic acid) (PLGA) nanoparticles was tested by using PET imaging to measure the kinetics of convection-enhanced delivery (CED) of nanoparticles of varying size to the rat brain. PET imaging enabled the direct observation of nanoparticle delivery by measurement of the spatial volume of distribution of radiolabeled nanoparticles as a function of time, both during and after the infusion. This work thus validates new methods for radiolabeling PEG-biotin derivatives and also provides insight into the fate of nanoparticles that have been infused directly into the brain. PMID:25322194

  9. Inhalable DNase I microparticles engineered with biologically active excipients.

    PubMed

    Osman, Rihab; Al Jamal, Khuloud T; Kan, Pei-Lee; Awad, Gehanne; Mortada, Nahed; El-Shamy, Abd-Elhameed; Alpar, Oya

    2013-12-01

    Highly viscous mucus poses a big challenge for the delivery of particulates carrying therapeutics to patients with cystic fibrosis. In this study, surface modifying DNase I loaded particles using different excipients to achieve better lung deposition, higher enzyme stability or better biological activity had been exploited. For the purpose, controlled release microparticles (MP) were prepared by co-spray drying DNase I with the polymer poly-lactic-co-glycolic acid (PLGA) and the biocompatible lipid surfactant 1,2-dipalmitoyl-Sn-phosphatidyl choline (DPPC) using various hydrophilic excipients. The effect of the included modifiers on the particle morphology, size, zeta potential as well as enzyme encapsulation efficiency, biological activity and release had been evaluated. Powder aerosolisation performance and particle phagocytosis by murine macrophages were also investigated. The results showed that more than 80% of enzyme activity was recovered after MP preparation and that selected surface modifiers greatly increased the enzyme encapsulation efficiency. The particle morphology was greatly modified altering in turn the powders inhalation indices where dextran, ovalbumin and chitosan hydrochloride increased considerably the respirable fraction compared to the normal hydrophilic carriers lactose and PVP. Despite of the improved aerosolisation caused by chitosan hydrochloride, yet retardation of chitosan coated particles in artificial mucus samples discouraged its application. On the other hand, dextran and polyanions enhanced DNase I effect in reducing cystic fibrosis mucus viscosity. DPPC proved good ability to reduce particles phagocytic uptake even in the presence of the selected adjuvants. The prepared MP systems were biocompatible with lung epithelial cells. To conclude, controlled release DNase I loaded PLGA-MP with high inhalation indices and enhanced mucolytic activity on CF sputum could be obtained by surface modifying the particles with PGA or dextran.

  10. [Experimental study on application recombinant human bone morphogenetic protein 2(rhBMP-2)/poly-lactide-co-glycolic acid (PLGA)/fibrin sealant(FS) on repair of rabbit radial bone defect].

    PubMed

    Fan, Zhongkai; Cao, Yang; Zhang, Zhe; Zhang, Mingchao; Lu, Wei; Tang, Lei; Yao, Qi; Lu, Gang

    2012-10-01

    This paper is aimed to investigate the repair of rabbit radial bone defect by the recombinant human bone morphogenetic protein 2/poly-lactideco-glycolic acid microsphere with fibrin sealant (rhBMP-2/PLGA/FS). The radial bone defect models were prepared using New Zealand white rabbits, which were randomly divided into 3 groups, experiment group which were injected with eMP-2/PLGA/FS at bone defect location, control group which were injected with FS at bone defect location, and blank control group without treatment. The ability of repairing bone defect was evaluated with X-ray radiograph. Bone mineral density in the defect regions was analysed using the level of ossification. The osteogenetic ability of repairing bone defect, the degradation of the material, the morphologic change and the bone formation were assessed by HE staining and Masson staining. The result showed that rhBMP-2/PLGA/FS had overwhelming superiority in the osteogenetic ability and quality of bone defect over the control group, and it could promote the repair of bone defect and could especially repair the radial bone defect of rabbit well. It may be a promising and efficient synthetic bone graft.

  11. Microparticles as a strategy for low-molecular-weight heparin delivery.

    PubMed

    Oliveira, Samantha S M; Oliveira, Fabiana S; Gaitani, Cristiane M; Marchetti, Juliana M

    2011-05-01

    The aims of this work were preparation and physical-chemical characterization of a microparticulate release system for delivery of enoxaparin sodium (ENX), a low-molecular-weight heparin, as a potential vehicle for optimization of deep venous thrombosis therapy. Microparticles (MPs) containing ENX were prepared from polylactide-co-glycolic acid [PLGA; (50:50)] by a double emulsification/solvent evaporation method. The preparation parameters, such as proportion ENX/PLGA, surfactant concentration, type, time, and speed of stirring, were evaluated. The encapsulation efficiency and yield process were determined and optimized, and the in vitro release profile was analysed at 35 days. The MPs showed a spherical shape with smooth and regular surfaces. The size distribution showed a unimodal profile with an average size of 2.0 ± 0.9 μ m. The low encapsulation efficiency (<30%), characteristic of hydrophilic macromolecules was improved, reaching 50.2% with a procedure yield of 71.3%. The in vitro profile of ENX release from the MPs was evaluated and showed pseudo-zero-order kinetics. This indicated that diffusion was the main drug release mechanism.

  12. Coaxial Electrospray of Ranibizumab-Loaded Microparticles for Sustained Release of Anti-VEGF Therapies

    PubMed Central

    Fischer, Andrew J.; Letson, Alan; Yuan, Shuai; Roberts, Cynthia J.; Xu, Ronald X.

    2015-01-01

    Age-related macular degeneration (AMD) is the leading cause of vision loss and blindness in people over age 65 in industrialized nations. Intravitreous injection of anti-VEGF (vascular endothelial growth factor) therapies, such as ranibizumab (trade name: Lucentis), provides an effective treatment option for neovascular AMD. We have developed an improved coaxial electrospray (CES) process to encapsulate ranibizumab in poly(lactic-co-glycolic) acid (PLGA) microparticles (MPs) for intravitreous injection and sustained drug release. This microencapsulation process is advantageous for maintaining the stability of the coaxial cone-jet configurations and producing drug-loaded MPs with as high as 70% encapsulation rate and minimal loss of bioactivitiy. The utility of this emerging process in intravitreous drug delivery has been demonstrated in both benchtop and in vivo experiments. The benchtop test simulates ocular drug release using PLGA MPs encapsulating a model drug. The in vivo experiment evaluates the inflammation and retinal cell death after intravitreal injection of the MPs in a chick model. The experimental results show that the drug-load MPs are able to facilitate sustained drug release for longer than one month. No significant long term microglia reaction or cell death is observed after intravitreal injection of 200 μg MPs. The present study demonstrates the technical feasibility of using the improved CES process to encapsulate water-soluble drugs at a high concentration for sustained release of anti-VEGF therapy. PMID:26273831

  13. Coaxial Electrospray of Curcumin-Loaded Microparticles for Sustained Drug Release

    PubMed Central

    Yuan, Shuai; Lei, Fan; Liu, Zhongfa; Tong, Qingping; Si, Ting; Xu, Ronald X.

    2015-01-01

    Curcumin exhibits superior anti-inflammatory, antiseptic and analgesic activities without significant side effects. However, clinical dissemination of this natural medicine is limited by its low solubility and poor bio-availability. To overcome this limitation, we propose to encapsulate curcumin in poly(lactic-co-glycolic acid) (PLGA) microparticles (MPs) by an improved coaxial electrospray (CES) process. This process is able to generate a stable cone-jet mode in a wide range of operation parameters in order to produce curcumin-loaded PLGA MPs with a clear core-shell structure and a designated size of several micrometers. In order to optimize the process outcome, the effects of primary operation parameters such as the applied electric voltages and the liquid flow rates are studied systemically. In vitro drug release experiments are also carried out for the CES-produced MPs in comparison with those by a single axial electrospray process. Our experimental results show that the CES process can be effectively controlled to encapsulate drugs of low aqueous solubility for high encapsulation efficiency and optimal drug release profiles. PMID:26208167

  14. Polypyrrole-Coated Electrospun PLGA Nanofibers for Neural Tissue Applications

    PubMed Central

    Lee, Jae Young; Bashur, Chris A.; Goldstein, Aaron S.; Schmidt, Christine E.

    2009-01-01

    Electrospinning is a promising approach to create nanofiber structures that are capable of supporting adhesion and guiding extension of neurons for nerve regeneration. Concurrently, electrical stimulation of neurons in the absence of topographical features also has been shown to guide axonal extension. Therefore, the goal of this study was to form electrically conductive nanofiber structures and to examine the combined effect of nanofiber structures and electrical stimulation. Conductive meshes were produced by growing polypyrrole (PPy) on random and aligned electrospun poly(lactic-co-glycolic acid) (PLGA) nanofibers, as confirmed by scanning electron micrographs and X-ray photon spectroscopy. PPy-PLGA electrospun meshes supported the growth and differentiation of rat pheochromocytoma 12 (PC12) cells and hippocampal neurons comparable to non-coated PLGA control meshes, suggesting that PPy-PLGA may be suitable as conductive nanofibers for neuronal tissue scaffolds. Electrical stimulation studies showed that PC12 cells, stimulated with a potential of 10 mV/cm on PPy-PLGA scaffolds, exhibited 40–50% longer neurites and 40–90% more neurite formation compared to unstimulated cells on the same scaffolds. In addition, stimulation of the cells on aligned PPy-PLGA fibers resulted in longer neurites and more neurite-bearing cells than stimulation on random PPy-PLGA fibers, suggesting a combined effect of electrical stimulation and topographical guidance and the potential use of these scaffolds for neural tissue applications. PMID:19501901

  15. Thermodynamic phase behaviour of indomethacin/PLGA formulations.

    PubMed

    Prudic, Anke; Lesniak, Anna-Katharina; Ji, Yuanhui; Sadowski, Gabriele

    2015-06-01

    In the current study, the phase behaviour of indomethacin and poly(lactic-co-glycolic acid) (PLGA) formulations was investigated as a function of the molecular weight and the copolymer composition of PLGA. The formulations were prepared by ball milling, and the phase behaviour, comprised of the glass-transition temperature of the formulations and the solubility of indomethacin in PLGA, was measured using modulated differential scanning calorimetry (mDSC). The results determined that the solubility of indomethacin in PLGA at room temperature was very low and increased with a corresponding decrease in the molecular weight of PLGA. The copolymer composition of PLGA had a minor effect on the indomethacin solubility. The effect of PLGA's molecular weight and copolymer composition on the solubility of indomethacin could be modelled using the Perturbed-Chain Statistical Associating Fluid Theory (PC-SAFT) with a high degree of accuracy when compared with the experimental data. The glass-transition temperatures had a negative deviation from the weighted mean of the glass-transition temperatures of the pure substances, which could be described by the Kwei-equation.

  16. Interaction of PLGA and trimethyl chitosan modified PLGA nanoparticles with mixed anionic/zwitterionic phospholipid bilayers studied using molecular dynamics simulations

    NASA Astrophysics Data System (ADS)

    Novak, Brian; Astete, Carlos; Sabliov, Cristina; Moldovan, Dorel

    2012-02-01

    Poly(lactic-co-glycolic acid) (PLGA) is a biodegradable polymer. Nanoparticles of PLGA are commonly used for drug delivery applications. The interaction of the nanoparticles with the cell membrane may influence the rate of their uptake by cells. Both PLGA and cell membranes are negatively charged, so adding positively charged polymers such as trimethyl chitosan (TMC) which adheres to the PLGA particles improves their cellular uptake. The interaction of 3 nm PLGA and TMC-modified-PLGA nanoparticles with lipid bilayers composed of mixtures of phosphatidylcholine and phosphatidylserine lipids was studied using molecular dynamics simulations. The free energy profiles as function of nanoparticles position along the normal direction to the bilayers were calculated, the distribution of phosphatidylserine lipids as a function of distance of the particle from the bilayer was calculated, and the time scale for particle motion in the directions parallel to the bilayer surface was estimated.

  17. Engineering a freestanding biomimetic cardiac patch using biodegradable poly(lactic-co-glycolic acid) (PLGA) and human embryonic stem cell-derived ventricular cardiomyocytes (hESC-VCMs).

    PubMed

    Chen, Yin; Wang, Junping; Shen, Bo; Chan, Camie W Y; Wang, Chaoyi; Zhao, Yihua; Chan, Ho N; Tian, Qian; Chen, Yangfan; Yao, Chunlei; Hsing, I-Ming; Li, Ronald A; Wu, Hongkai

    2015-03-01

    Microgrooved thin PLGA film (≈30 μm) is successfully fabricated on a Teflon mold, which could be readily peeled off and is used for the construction of a biomimetic cardiac patch. The contraction of it is studied with optical mapping on transmembrane action potential. Our results suggest that steady-state contraction could be easily established on it under regular electrical stimuli. Besides, the biomimetic cardiac patch recapitulates the anisotropic electrophysiological feature of native cardiac tissue and is much more refractory to premature stimuli than the random one constructed with non-grooved PLGA film, as proved by the reduced incidence of arrhythmia. Considering the good biocompatibility of PLGA as demonstrated in our study and the biodegradability of it, our biomimetic cardiac patch may find applications in the treatment of myocardial infarction. Moreover, the Teflon mold could be applied in the fabrication of various scaffolds with fine features for other tissues.

  18. [Transport of PLGA nanoparticles across Caco-2/HT29-MTX co-cultured cells].

    PubMed

    Wen, Zhen; Li, Gang; Lin, Dong-Hai; Wang, Jun-Teng; Qin, Li-Fang; Guo, Gui-Ping

    2013-12-01

    The present study is to establish Caco-2/HT29-MTX co-cultured cells and investigate the transport capability of PLGA nanoparticles with different surface chemical properties across Caco-2/HT29-MTX co-cultured cells. PLGA-NPs, mPEG-PLGA-NPs and chitosan coated PLGA-NPs were prepared by nanoprecipitation method using poly(lactic-co-glycolic acid) as carrier material with surface modified by methoxy poly(ethylene glycol) and chitosan. The particle size and zeta potential of nanoparticles were measured by dynamic light scattering. Coumarin 6 was used as a fluorescent marker in the transport of nanoparticles investigated by confocal laser scanning microscopy. The transport of furanodiene (FDE) loaded nanoparticles was quantitively determined by high performance liquid chromatography. Colchicine and nocodazole were used in the transport study to explore the involved endocytosis mechanisms of nanoparticles. Distribution of the tight junction proteins ZO-1 was also analyzed by immunofluorescence staining. The results showed that the nanoparticles dispersed uniformly. The zeta potential of PLGA-NPs was negative, the mPEG-PLGA-NPs was close to neutral and the CS-PLGA-NPs was positive. The entrapment efficiency of FDE in all nanoparticles was higher than 75%. The transport capability of mPEG-PLGA-NPs across Caco-2/HT29-MTX co-cultured cells was higher than that of PLGA-NPs and CS-PLGA-NPs. Colchicine and nocodazole could significantly decrease the transport amount of nanoparticles. mPEG-PLGA-NPs could obviously reduce the distribution of ZO-1 protein than PLGA-NPs and CS-PLGA-NPs. The transport mechanism of PLGA-NPs and mPEG-PLGA-NPs were indicated to be a combination of endocytosis and paracellular way, while CS-PLGA-NPs mainly relied on the endocytosis way. PEG coating could shield the surface charge and enhance the hydrophilicity of PLGA nanoparticles, which leads mPEG-PLGA-NPs to possess higher anti-adhesion activity. As a result, mPEG-PLGA-NPs could penetrate the mucus

  19. Laser irradiated fluorescent perfluorocarbon microparticles in 2-D and 3-D breast cancer cell models

    PubMed Central

    Niu, Chengcheng; Wang, Long; Wang, Zhigang; Xu, Yan; Hu, Yihe; Peng, Qinghai

    2017-01-01

    Perfluorocarbon (PFC) droplets were studied as new generation ultrasound contrast agents via acoustic or optical droplet vaporization (ADV or ODV). Little is known about the ODV irradiated vaporization mechanisms of PFC-microparticle complexs and the stability of the new bubbles produced. In this study, fluorescent perfluorohexane (PFH) poly(lactic-co-glycolic acid) (PLGA) particles were used as a model to study the process of particle vaporization and bubble stability following excitation in two-dimensional (2-D) and three-dimensional (3-D) cell models. We observed localization of the fluorescent agent on the microparticle coating material initially and after vaporization under fluorescence microscopy. Furthermore, the stability and growth dynamics of the newly created bubbles were observed for 11 min following vaporization. The particles were co-cultured with 2-D cells to form 3-D spheroids and could be vaporized even when encapsulated within the spheroids via laser irradiation, which provides an effective basis for further work. PMID:28262671

  20. Subcutaneous inverse vaccination with PLGA particles loaded with a MOG peptide and IL-10 decreases the severity of experimental autoimmune encephalomyelitis.

    PubMed

    Cappellano, Giuseppe; Woldetsadik, Abiy Demeke; Orilieri, Elisabetta; Shivakumar, Yogesh; Rizzi, Manuela; Carniato, Fabio; Gigliotti, Casimiro Luca; Boggio, Elena; Clemente, Nausicaa; Comi, Cristoforo; Dianzani, Chiara; Boldorini, Renzo; Chiocchetti, Annalisa; Renò, Filippo; Dianzani, Umberto

    2014-09-29

    "Inverse vaccination" refers to antigen-specific tolerogenic immunization treatments that are capable of inhibiting autoimmune responses. In experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis (MS), initial trials using purified myelin antigens required repeated injections because of the rapid clearance of the antigens. This problem has been overcome by DNA-based vaccines encoding for myelin autoantigens alone or in combination with "adjuvant" molecules, such as interleukin (IL)-4 or IL-10, that support regulatory immune responses. Phase I and II clinical trials with myelin basic protein (MBP)-based DNA vaccines showed positive results in reducing magnetic resonance imaging (MRI)-measured lesions and inducing tolerance to myelin antigens in subsets of MS patients. However, DNA vaccination has potential risks that limit its use in humans. An alternative approach could be the use of protein-based inverse vaccines loaded in polymeric biodegradable lactic-glycolic acid (PLGA) nano/microparticles (NP) to obtain the sustained release of antigens and regulatory adjuvants. The aim of this work was to test the effectiveness of PLGA-NP loaded with the myelin oligodendrocyte glycoprotein (MOG)35-55 autoantigen and recombinant (r) IL-10 to inverse vaccinate mice with EAE. In vitro experiments showed that upon encapsulation in PLGA-NP, both MOG35-55 and rIL-10 were released for several weeks into the supernatant. PLGA-NP did not display cytotoxic or proinflammatory activity and were partially endocytosed by phagocytes. In vivo experiments showed that subcutaneous prophylactic and therapeutic inverse vaccination with PLGA-NP loaded with MOG35-55 and rIL-10 significantly ameliorated the course of EAE induced with MOG35-55 in C57BL/6 mice. Moreover, they decreased the histopathologic lesions in the central nervous tissue and the secretion of IL-17 and interferon (IFN)-γ induced by MOG35-55 in splenic T cells in vitro. These data suggest that

  1. Preparation and characterization of bee venom-loaded PLGA particles for sustained release.

    PubMed

    Park, Min-Ho; Jun, Hye-Suk; Jeon, Jong-Woon; Park, Jin-Kyu; Lee, Bong-Joo; Suh, Guk-Hyun; Park, Jeong-Sook; Cho, Cheong-Weon

    2016-12-14

    Bee venom-loaded poly(lactic-co-glycolic acid) (PLGA) particles were prepared by double emulsion-solvent evaporation, and characterized for a sustained-release system. Factors such as the type of organic solvent, the amount of bee venom and PLGA, the type of PLGA, the type of polyvinyl alcohol, and the emulsification method were considered. Physicochemical properties, including the encapsulation efficiency, drug loading, particle size, zeta-potential and surface morphology were examined by Fourier transform infrared (FT-IR) spectroscopy, differential scanning calorimetry (DSC), and X-ray diffraction (XRD). The size of the bee venom-loaded PLGA particles was 500 nm (measured using sonication). Zeta-potentials of the bee venom-loaded PLGA particles were negative owing to the PLGA. FT-IR results demonstrated that the bee venom was completely encapsulated in the PLGA particles, indicated by the disappearance of the amine and amide peaks. In addition, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis indicated that the bee venom in the bee venom-loaded PLGA particles was intact. In vitro release of the bee venom from the bee venom-loaded PLGA particles showed a sustained-release profile over 1 month. Bee venom-loaded PLGA particles can help improve patients' quality of life by reducing the number of injections required.

  2. Surface Mechanical and Rheological Behaviors of Biocompatible Poly((D,L-lactic acid-ran-glycolic acid)-block-ethylene glycol) (PLGA-PEG) and Poly((D,L-lactic acid-ran-glycolic acid-ran-ε-caprolactone)-block-ethylene glycol) (PLGACL-PEG) Block Copolymers at the Air-Water Interface

    SciTech Connect

    Kim, Hyun Chang; Lee, Hoyoung; Khetan, Jawahar; Won, You-Yeon

    2016-02-01

    Air–water interfacial monolayers of poly((d,l-lactic acid-ran-glycolic acid)-block-ethylene glycol) (PLGA–PEG) exhibit an exponential increase in surface pressure under high monolayer compression. In order to understand the molecular origin of this behavior, a combined experimental and theoretical investigation (including surface pressure–area isotherm, X-ray reflectivity (XR) and interfacial rheological measurements, and a self-consistent field (SCF) theoretical analysis) was performed on air–water monolayers formed by a PLGA–PEG diblock copolymer and also by a nonglassy analogue of this diblock copolymer, poly((d,l-lactic acid-ran-glycolic acid-ran-caprolactone)-block-ethylene glycol) (PLGACL–PEG). The combined results of this study show that the two mechanisms, i.e., the glass transition of the collapsed PLGA film and the lateral repulsion of the PEG brush chains that occur simultaneously under lateral compression of the monolayer, are both responsible for the observed PLGA–PEG isotherm behavior. Upon cessation of compression, the high surface pressure of the PLGA–PEG monolayer typically relaxes over time with a stretched exponential decay, suggesting that in this diblock copolymer situation, the hydrophobic domain formed by the PLGA blocks undergoes glass transition in the high lateral compression state, analogously to the PLGA homopolymer monolayer. In the high PEG grafting density regime, the contribution of the PEG brush chains to the high monolayer surface pressure is significantly lower than what is predicted by the SCF model because of the many-body attraction among PEG segments (referred to in the literature as the “n-cluster” effects). The end-grafted PEG chains were found to be protein resistant even under the influence of the “n-cluster” effects.

  3. Engineering of lipid-coated PLGA nanoparticles with a tunable payload of diagnostically active nanocrystals for medical imaging†

    PubMed Central

    Mieszawska, Aneta J.; Gianella, Anita; Cormode, David P.; Zhao, Yiming; Meijerink, Andries; Langer, Robert; Farokhzad, Omid C.; Fayad, Zahi A.; Mulder, Willem J. M.

    2013-01-01

    Polylactic-co-glycolic acid (PLGA) based nanoparticles are biocompatible and biodegradable and therefore have been extensively investigated as therapeutic carriers. Here, we engineered diagnostically active PLGA nanoparticles that incorporate high payloads of nanocrystals into their core for tunable bioimaging features. We accomplished this through esterification reactions of PLGA to generate polymers modified with nanocrystals. The PLGA nanoparticles formed from modified PLGA polymers that were functionalized with either gold nanocrystals or quantum dots exhibited favorable features for computed tomography and optical imaging, respectively. PMID:22555311

  4. Effect of micro-particles on cavitation erosion of Ti6Al4V alloy in sulfuric acid solution.

    PubMed

    Li, D G; Long, Y; Liang, P; Chen, D R

    2017-05-01

    The influences of micro-particles on ultrasonic cavitation erosion of Ti6Al4V alloy in 0.1M H2SO4 solution were investigated using mass loss weight, scanning electron microscopy (SEM) and white light interferometer. Mass loss results revealed that the cavitation erosion damage obviously decreased with increasing particle size and mass concentration. Open circuit potential recorded during cavitation erosion shifted to positive direction with the decreased mass loss. Meanwhile, the mass loss sharply decreased with applying a positive potential during the entire ultrasonic cavitation erosion, and the relationship between the open circuit potential and the cavitation erosion resistance was discussed.

  5. Muscle regeneration by adipose tissue-derived adult stem cells attached to injectable PLGA spheres.

    PubMed

    Kim, MiJung; Choi, Yu Suk; Yang, Seung Hye; Hong, Hea-Nam; Cho, Sung-Woo; Cha, Sang Myun; Pak, Jhang Ho; Kim, Chan Wha; Kwon, Seog Woon; Park, Chan Jeoung

    2006-09-22

    The [corrected] use of adult stem cells for cell-based tissue engineering and regeneration strategies represents a promising approach for skeletal muscle repair. We have evaluated the combination of adipose tissue-derived adult stem cells (ADSCs) obtained from autologous liposuction and injectable poly(lactic-co-glycolic acid) (PLGA) spheres for muscle regeneration. ADSCs attached to PLGA spheres and PLGA spheres alone were cultured in myogenic medium for 21 days and injected subcutaneously into the necks of nude mice. After 30 and 60 days, the mice were sacrificed, and newly formed tissues were analyzed by immunostaining, H and E staining, and RT-PCR. We found that ADSCs attached to PLGA spheres, but not PLGA spheres alone, were able to generate muscle tissue. These findings suggest that ADSCs and PLGA spheres are useful materials for muscle tissue engineering and that their combination can be used in clinical settings for muscle regeneration.

  6. Release of insulin from PLGA-alginate dressing stimulates regenerative healing of burn wounds in rats.

    PubMed

    Dhall, Sandeep; Silva, João P; Liu, Yan; Hrynyk, Michael; Garcia, Monika; Chan, Alex; Lyubovitsky, Julia; Neufeld, Ronald J; Martins-Green, Manuela

    2015-12-01

    Burn wound healing involves a complex set of overlapping processes in an environment conducive to ischaemia, inflammation and infection costing $7.5 billion/year in the U.S.A. alone, in addition to the morbidity and mortality that occur when the burns are extensive. We previously showed that insulin, when topically applied to skin excision wounds, accelerates re-epithelialization and stimulates angiogenesis. More recently, we developed an alginate sponge dressing (ASD) containing insulin encapsulated in PLGA [poly(D,L-lactic-co-glycolic acid)] microparticles that provides a sustained release of bioactive insulin for >20 days in a moist and protective environment. We hypothesized that insulin-containing ASD accelerates burn healing and stimulates a more regenerative, less scarring healing. Using heat-induced burn injury in rats, we show that burns treated with dressings containing 0.04 mg insulin/cm(2) every 3 days for 9 days have faster closure, a higher rate of disintegration of dead tissue and decreased oxidative stress. In addition, in insulin-treated wounds, the pattern of neutrophil inflammatory response suggests faster clearing of the burned dead tissue. We also observe faster resolution of the pro-inflammatory macrophages. We also found that insulin stimulates collagen deposition and maturation with the fibres organized more like a basket weave (normal skin) than aligned and cross-linked (scar tissue). In summary, application of ASD-containing insulin-loaded PLGA particles on burns every 3 days stimulates faster and more regenerative healing. These results suggest insulin as a potential therapeutic agent in burn healing and, because of its long history of safe use in humans, insulin could become one of the treatments of choice when repair and regeneration are critical for proper tissue function.

  7. Systemic delivery to central nervous system by engineered PLGA nanoparticles

    PubMed Central

    Cai, Qiang; Wang, Long; Deng, Gang; Liu, Junhui; Chen, Qianxue; Chen, Zhibiao

    2016-01-01

    Neurological disorders are an important global public health problem, but pharmaceutical treatments are limited due to drug access to the central nervous system being restricted by the blood-brain barrier (BBB). Poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NPs) are one of the most promising drug and gene delivery systems for crossing the BBB. While these systems offer great promise, PLGA NPs also have some intrinsic drawbacks and require further engineering for clinical and research applications. Multiple strategies have been developed for using PLGA NPs to deliver compounds across the BBB. We classify these strategies into three categories according to the adaptations made to the PLGA NPs (1) to facilitate travel from the injection site (pre-transcytosis strategies); (2) to enhance passage across the brain endothelial cells (BBB transcytosis strategies) and (3) to achieve targeting of the impaired nervous system cells (post-transcytosis strategies). PLGA NPs modified according to these three strategies are denoted first, second, and third generation NPs, respectively. We believe that fusing these three strategies to engineer multifunctional PLGA NPs is the only way to achieve translational applications. PMID:27158367

  8. Synthesis and characterization of magnetite/PLGA/chitosan nanoparticles

    NASA Astrophysics Data System (ADS)

    Ibarra, Jaime; Melendres, Julio; Almada, Mario; Burboa, María G.; Taboada, Pablo; Juárez, Josué; Valdez, Miguel A.

    2015-09-01

    In this work, we report the synthesis and characterization of a new hybrid nanoparticles system performed by magnetite nanoparticles, loaded in a PLGA matrix, and stabilized by different concentrations of chitosan. Magnetite nanoparticles were hydrophobized with oleic acid and entrapped in a PLGA matrix by the emulsion solvent evaporation method, after that, magnetite/PLGA/chitosan nanoparticles were obtained by adding dropwise magnetite/PLGA nanoparticles in chitosan solutions. Magnetite/PLGA nanoparticles produced with different molar ratios did not show significant differences in size and the 3:1 molar ratio showed best spherical shapes as well as uniform particle size. Isothermal titration calorimetry studies demonstrated that the first stage of PLGA-chitosan interaction is mostly regulated by electrostatic forces. Based on a single set of identical sites model, we obtained for the average number of binding sites a value of 3.4, which can be considered as the number of chitosan chains per nanoparticle. This value was confirmed by using a model based on the DLVO theory and fitting zeta potential measurements of magnetite/PLGA/chitosan nanoparticles. From the adjusted parameters, we found that an average number of chitosan molecules of 3.6 per nanoparticle are attached onto the surface of the PLGA matrix. Finally, we evaluated the effect of surface charge of nanoparticles on a membrane model of endothelial cells performed by a mixture of three phospholipids at the air-water interface. Different isotherms and adsorption curves show that cationic surface of charged nanoparticles strongly interact with the phospholipids mixture and these results can be the basis of future experiments to understand the nanoparticles- cell membrane interaction.

  9. Thermo-sensitive hydrogel PLGA-PEG-PLGA as a vaccine delivery system for intramuscular immunization.

    PubMed

    Wang, Xiaoyan; Zhang, Yu; Xue, Wei; Wang, Hong; Qiu, Xiaozhong; Liu, Zonghua

    2016-11-25

    In this work, we explored the potential of thermo-sensitive PLGA-PEG-PLGA with sol-gel transition temperature around 32℃ as an intramuscular vaccine delivery system by using ovalbumin as a model antigen. First, in vitro release test showed that the PLGA-PEG-PLGA-deriving hydrogels could release ovalbumin in vitro in a more sustainable way. From fluorescence living imaging, 50-200 mg/mL of PLGA-PEG-PLGA formulations could release antigen in a sustainable manner in vivo, suggesting that the PLGA-PEG-PLGA hydrogel worked as an antigen-depot. Further, the sustainable antigen release from the PLGA-PEG-PLGA hydrogels increased antigen availability in the spleens of the immunized mice. The intramuscular immunization results showed that 50-200 mg/mL of PLGA-PEG-PLGA formulations promoted significantly more potent antigen-specific IgG immune response. In addition, 200 mg/mL of PLGA-PEG-PLGA formulation significantly enhanced the secretion of both Th1 and Th2 cytokines. From in vitro splenocyte proliferation assay, 50-200 mg/mL of PLGA-PEG-PLGA formulations all initiated significantly higher splenocyte activation. These results indicate that the thermo-sensitive and injectable PLGA-PEG-PLGA hydrogels (particularly, 200 mg/mL of PLGA-PEG-PLGA-based hydrogel) own promising potential as an intramuscular vaccine delivery system.

  10. Controlled Release Pulmonary Administration of Curcumin Using Swellable Biocompatible Microparticles

    PubMed Central

    El-Sherbiny, Ibrahim M.; Smyth, Hugh D. C.

    2012-01-01

    This study involves a promising approach to achieve sustained pulmonary drug delivery. Dry powder particulate carriers were engineered to allow simultaneous aerosol lung delivery, evasion of macrophage uptake, and sustained drug release through a controlled polymeric architecture. Chitosan grafted with PEG was synthesized and characterized (FTIR, EA, DSC and 2D-XRD). Then, a series of respirable amphiphilic hydrogel microparticles were developed via spray drying of curcumin-loaded PLGA nanoparticles with chitosan-grafted-PEG or chitosan. The nano and microparticles were fully characterized using an array of physicochemical analytical methods including particle size, surface morphology, dynamic swelling, density, moisture content and biodegradation rates. The PLGA nanoparticles and the hydrogel microspheres encapsulating the curcumin-loaded PLGA nanoparticles showed average size of (221-243 nm) and (3.1-3.9 μm), respectively. The developed carriers attained high swelling within a few minutes, showed low moisture content as dry powders (0.9-1.8%), desirable biodegradation rates, high drug loading (up to 97%), and good sustained release. An aerosolization study was conducted using a next generation impactor and promising aerosolization characteristics were shown. In vitro macrophage uptake studies, cytotoxicity and in-vitro TNF-α assays were performed for the investigated particles. These assays revealed promising bio-interactions for the respirable/swellable nano-micro particles developed in this study as potential carriers for sustained pulmonary drug delivery. PMID:22136259

  11. Periodontal tissue regeneration by transplantation of rat adipose-derived stromal cells in combination with PLGA-based solid scaffolds.

    PubMed

    Akita, Daisuke; Morokuma, Masakazu; Saito, Yoko; Yamanaka, Katsuyuki; Akiyama, Yuko; Sato, Momoko; Mashimo, Takayuki; Toriumi, Taku; Arai, Yoshinori; Kaneko, Tadashi; Tsukimura, Naoki; Isokawa, Keitaro; Ishigami, Tomohiko; Honda, Masaki J

    2014-01-01

    Regeneration of damaged periodontium is challenging due to its multi-tissue composition. Mesenchymalstem cell-based approaches using adipose-derived stromal cells (ASCs) may contribute to periodontal reconstruction, particularly when combined with the use of scaffolds to maintain a space for new tissue growth. The aim of this study was to assess the regenerative potential of ASCs derived from inbred or outbred rats in combination with novel solid scaffolds composed of PLGA (Poly D,L-lactic-co-glycolic acid) (PLGA-scaffolds). Cultured ASCs seeded onto PLGA scaffolds (ASCs/PLGA) or PLGA-scaffolds (PLGA) alone were transplanted into periodontal fenestration defects created in F344 or Sprague Dawley (SD) rats. Micro-CT analysis showed a significantly higher percentage of bone growth in the ASCs/PLGA groups compared with the PLGA-alone groups at five weeks after surgery. Similarly, histomorphometric analysis demonstrated thicker growth of periodontal ligament and cementum layers in the ASCs/PLGA-groups compared with the PLGA-alone groups. In addition, transplanted DiI-labeled ASCs were observed in the periodontal regenerative sites. The present investigation demonstrated the marked ability of ASCs in combination with PLGA scaffolds to repair periodontal defects.

  12. A biodegradable killer microparticle to selectively deplete antigen-specific T cells in vitro and in vivo

    PubMed Central

    Wang, Wei; Fang, Kun; Li, Miao-Chen; Chang, Di; Shahzad, Khawar Ali; Xu, Tao; Zhang, Lei; Gu, Ning; Shen, Chuan-Lai

    2016-01-01

    The specific eradication of pathogenic T cells for the treatment of allograft rejections and autoimmune disorders without impairment of overall immune function is a fundamental goal. Here, cell-sized poly(lactic-co-glycolic acid) microparticles (PLGA MPs) were prepared as a scaffold to co-display the peptide/major histocompatibility complex (pMHC, target antigen) and anti-Fas monoclonal antibody (apoptosis-inducing molecule) for the generation of biodegradable killer MPs. Ovalbumin (OVA) antigen-targeted killer MPs significantly depleted OVA-specific CD8+ T cells in an antigen-specific manner, both in vitro and in OT-1 mice. After intravenous administration, the killer MPs predominantly accumulated in the liver, lungs, and gut of OT-1 mice with a retention time of up to 48 hours. The killing effects exerted by killer MPs persisted for 4 days after two injections. Moreover, the H-2Kb alloantigen-targeted killer MPs were able to eliminate low-frequency alloreactive T cells and prolong alloskin graft survival for 41.5 days in bm1 mice. Our data indicate that PLGA-based killer MPs are capable of specifically depleting pathogenic T cells, which highlights their therapeutic potential for treating allograft rejection and autoimmune disorders. PMID:26910923

  13. A biodegradable killer microparticle to selectively deplete antigen-specific T cells in vitro and in vivo.

    PubMed

    Wang, Wei; Fang, Kun; Li, Miao-Chen; Chang, Di; Shahzad, Khawar Ali; Xu, Tao; Zhang, Lei; Gu, Ning; Shen, Chuan-Lai

    2016-03-15

    The specific eradication of pathogenic T cells for the treatment of allograft rejections and autoimmune disorders without impairment of overall immune function is a fundamental goal. Here, cell-sized poly(lactic-co-glycolic acid) microparticles (PLGA MPs) were prepared as a scaffold to co-display the peptide/major histocompatibility complex (pMHC, target antigen) and anti-Fas monoclonal antibody (apoptosis-inducing molecule) for the generation of biodegradable killer MPs. Ovalbumin (OVA) antigen-targeted killer MPs significantly depleted OVA-specific CD8+ T cells in an antigen-specific manner, both in vitro and in OT-1 mice. After intravenous administration, the killer MPs predominantly accumulated in the liver, lungs, and gut of OT-1 mice with a retention time of up to 48 hours. The killing effects exerted by killer MPs persisted for 4 days after two injections. Moreover, the H-2Kb alloantigen-targeted killer MPs were able to eliminate low-frequency alloreactive T cells and prolong alloskin graft survival for 41.5 days in bm1 mice. Our data indicate that PLGA-based killer MPs are capable of specifically depleting pathogenic T cells, which highlights their therapeutic potential for treating allograft rejection and autoimmune disorders.

  14. Microparticles with hierarchical porosity

    DOEpatents

    Petsev, Dimiter N; Atanassov, Plamen; Pylypenko, Svitlana; Carroll, Nick; Olson, Tim

    2012-12-18

    The present disclosure provides oxide microparticles with engineered hierarchical porosity and methods of manufacturing the same. Also described are structures that are formed by templating, impregnating, and/or precipitating the oxide microparticles and method for forming the same. Suitable applications include catalysts, electrocatalysts, electrocatalysts support materials, capacitors, drug delivery systems, sensors and chromatography.

  15. Understanding greater cardiomyocyte functions on aligned compared to random carbon nanofibers in PLGA.

    PubMed

    Asiri, Abdullah M; Marwani, Hadi M; Khan, Sher Bahadar; Webster, Thomas J

    2015-01-01

    Previous studies have demonstrated greater cardiomyocyte density on carbon nanofibers (CNFs) aligned (compared to randomly oriented) in poly(lactic-co-glycolic acid) (PLGA) composites. Although such studies demonstrated a closer mimicking of anisotropic electrical and mechanical properties for such aligned (compared to randomly oriented) CNFs in PLGA composites, the objective of the present in vitro study was to elucidate a deeper mechanistic understanding of how cardiomyocyte densities recognize such materials to respond more favorably. Results showed lower wettability (greater hydrophobicity) of CNFs embedded in PLGA compared to pure PLGA, thus providing evidence of selectively lower wettability in aligned CNF regions. Furthermore, the results correlated these changes in hydrophobicity with increased adsorption of fibronectin, laminin, and vitronectin (all proteins known to increase cardiomyocyte adhesion and functions) on CNFs in PLGA compared to pure PLGA, thus providing evidence of selective initial protein adsorption cues on such CNF regions to promote cardiomyocyte adhesion and growth. Lastly, results of the present in vitro study further confirmed increased cardiomyocyte functions by demonstrating greater expression of important cardiomyocyte biomarkers (such as Troponin-T, Connexin-43, and α-sarcomeric actin) when CNFs were aligned compared to randomly oriented in PLGA. In summary, this study provided evidence that cardiomyocyte functions are improved on CNFs aligned in PLGA compared to randomly oriented in PLGA since CNFs are more hydrophobic than PLGA and attract the adsorption of key proteins (fibronectin, laminin, and vironectin) that are known to promote cardiomyocyte adhesion and expression of important cardiomyocyte functions. Thus, future studies should use this knowledge to further design improved CNF:PLGA composites for numerous cardiovascular applications.

  16. HDL-mimetic PLGA nanoparticle to target atherosclerosis plaque macrophages.

    PubMed

    Sanchez-Gaytan, Brenda L; Fay, Francois; Lobatto, Mark E; Tang, Jun; Ouimet, Mireille; Kim, YongTae; van der Staay, Susanne E M; van Rijs, Sarian M; Priem, Bram; Zhang, Liangfang; Fisher, Edward A; Moore, Kathryn J; Langer, Robert; Fayad, Zahi A; Mulder, Willem J M

    2015-03-18

    High-density lipoprotein (HDL) is a natural nanoparticle that exhibits an intrinsic affinity for atherosclerotic plaque macrophages. Its natural targeting capability as well as the option to incorporate lipophilic payloads, e.g., imaging or therapeutic components, in both the hydrophobic core and the phospholipid corona make the HDL platform an attractive nanocarrier. To realize controlled release properties, we developed a hybrid polymer/HDL nanoparticle composed of a lipid/apolipoprotein coating that encapsulates a poly(lactic-co-glycolic acid) (PLGA) core. This novel HDL-like nanoparticle (PLGA-HDL) displayed natural HDL characteristics, including preferential uptake by macrophages and a good cholesterol efflux capacity, combined with a typical PLGA nanoparticle slow release profile. In vivo studies carried out with an ApoE knockout mouse model of atherosclerosis showed clear accumulation of PLGA-HDL nanoparticles in atherosclerotic plaques, which colocalized with plaque macrophages. This biomimetic platform integrates the targeting capacity of HDL biomimetic nanoparticles with the characteristic versatility of PLGA-based nanocarriers.

  17. Fabrication and in vitro biocompatibility of biomorphic PLGA/nHA composite scaffolds for bone tissue engineering.

    PubMed

    Qian, Junmin; Xu, Weijun; Yong, Xueqing; Jin, Xinxia; Zhang, Wei

    2014-03-01

    In this study, biomorphic poly(dl-lactic-co-glycolic acid)/nano-hydroxyapatite (PLGA/nHA) composite scaffolds were successfully prepared using cane as a template. The porous morphology, phase, compression characteristics and in vitro biocompatibility of the PLGA/nHA composite scaffolds and biomorphic PLGA scaffolds as control were investigated. The results showed that the biomorphic scaffolds preserved the original honeycomb-like architecture of cane and exhibited a bimodal porous structure. The average channel diameter and micropore size of the PLGA/nHA composite scaffolds were 164 ± 52 μm and 13 ± 8 μm, respectively, with a porosity of 89.3 ± 1.4%. The incorporation of nHA into PLGA decreased the degree of crystallinity of PLGA, and significantly improved the compressive modulus of biomorphic scaffolds. The in vitro biocompatibility evaluation with MC3T3-E1 cells demonstrated that the biomorphic PLGA/nHA composite scaffolds could better support cell attachment, proliferation and differentiation than the biomorphic PLGA scaffolds. The localization depth of MC3T3-E1 cells within the channels of the biomorphic PLGA/nHA composite scaffolds could reach approximately 400 μm. The results suggested that the biomorphic PLGA/nHA composite scaffolds were promising candidates for bone tissue engineering.

  18. In vitro biocompatibility of polypyrrole/PLGA conductive nanofiber scaffold with cultured rat hepatocytes

    NASA Astrophysics Data System (ADS)

    Chu, Xue-Hui; Xu, Qian; Feng, Zhang-Qi; Xiao, Jiang-Qiang; Li, Qiang; Sun, Xi-Tai; Cao, Yang; Ding, Yi-Tao

    2014-09-01

    To intruduce conductive biomaterial into liver tissue engineering, a conductive nanofiber scaffold, polypyrrole/poly(lactic-co-glycolic)acid(PLGA), was designed and prepared via electro-spinning and oxidative polymerization. Effects of the scaffold on hepatocyte adhesion, viability and function were then investigated. SEM revealed pseudopodium formation and abundant extracellular matrix on the surface of PLGA membrane and polypyrrole/PLGA membrane. The adhesion rate, cellular activity, urea synthesis and albumin secretion of the hepatocytes cultured on polypyrrole/PLGA group were similar to those on the PLGA group, but were significantly higher than those on the control group. There were no significant differences in concentrations of LDH and TNF-α among three groups. These results suggested the potential application of this conductive nanofiber scaffold as a suitable substratum for hepatocyte culturing in liver tissue engineering.

  19. Fabrication of pillared PLGA microvessel scaffold using femtosecond laser ablation

    PubMed Central

    Wang, Hsiao-Wei; Cheng, Chung-Wei; Li, Ching-Wen; Chang, Han-Wei; Wu, Ping-Han; Wang, Gou-Jen

    2012-01-01

    One of the persistent challenges confronting tissue engineering is the lack of intrinsic microvessels for the transportation of nutrients and metabolites. An artificial microvascular system could be a feasible solution to this problem. In this study, the femtosecond laser ablation technique was implemented for the fabrication of pillared microvessel scaffolds of polylactic-co-glycolic acid (PLGA). This novel scaffold facilitates implementation of the conventional cell seeding process. The progress of cell growth can be observed in vitro by optical microscopy. The problems of becoming milky or completely opaque with the conventional PLGA scaffold after cell seeding can be resolved. In this study, PLGA microvessel scaffolds consisting of 47 μm × 80 μm pillared branches were produced. Results of cell culturing of bovine endothelial cells demonstrate that the cells adhere well and grow to surround each branch of the proposed pillared microvessel networks. PMID:22605935

  20. Elucidation of the physicomechanical and ab initio quantum energy transitions of a crosslinked PLGA scaffold.

    PubMed

    Sibambo, Sibongile R; Pillay, Viness; Choonara, Yahya E; Khan, Riaz A; Sweet, Joe L

    2007-09-01

    This study elucidated the in vitro physicomechanical transitions of a crosslinked polylactic-co-glycolic acid (PLGA) scaffold, utilizing quantum mechanics to compute the ab initio energy requirements of a salted-out and subsequently crosslinked PLGA scaffold interacting with simulated physiological fluid, phosphate buffered saline (PBS) (pH 7.4, 37 degrees C) at a molecular level. Twenty-six salted-out PLGA scaffolds were formulated using a four factor, two centerpoint quadratic Face-Centered Central Composite Design (FCCD). PLGA molecular mass, PLGA concentration, water volume and salting-out reaction time were the dependant formulation variables. Subsequent to PLGA solubilization in dimethyl formamide (DMF), protonated water was added to induce salting-out of PLGA into a scaffolds that were immersed in PBS, oscillated at 100 rpm, and analyzed at pre-determined time intervals for their physicomechanical and ab initio quantum energy transitions. Results indicated that the matrix resilience (MR) decreased with longer incubation periods (MR=35-45%) at day 30. Scaffolds salted-out using higher PLGA concentrations exhibited minimal changes in MR and the matrix ability to absorb energy was found to closely correlate with the scaffold residence time in PBS. Spartan-based ab initio quantum energy predictions elucidated the potential scaffold stability from a molecular viewpoint and its suitability for use in rate-modulated drug delivery.

  1. Surface modification of PLGA nanoparticles by carbopol to enhance mucoadhesion and cell internalization.

    PubMed

    Surassmo, Suvimol; Saengkrit, Nattika; Ruktanonchai, Uracha Rungsardthong; Suktham, Kunat; Woramongkolchai, Noppawan; Wutikhun, Tuksadon; Puttipipatkhachorn, Satit

    2015-06-01

    Mucoadhesive poly (lactic-co-glycolic acid) (PLGA) nanoparticles having a modified shell-matrix derived from polyvinyl alcohol (PVA) and Carbopol (CP), a biodegradable polymer coating, to improve the adhesion and cell transfection properties were developed. The optimum formulations utilized a CP concentration in the range of 0.05-0.2%w/v, and were formed using modified emulsion-solvent evaporation technique. The resulting CP-PLGA nanoparticles were characterized in terms of their physical and chemical properties. The absorbed CP on the PLGA shell-matrix was found to affect the particle size and surface charge, with 0.05% CP giving rise to smooth spherical particles (0.05CP-PLGA) with the smallest size (285.90 nm), and strong negative surface charge (-25.70 mV). The introduction of CP results in an enhancement of the mucoadhesion between CP-PLGA nanoparticles and mucin particles. In vitro cell internalization studies highlighted the potential of 0.05CP-PLGA nanoparticles for transfection into SiHa cells, with uptake being time dependent. Additionally, cytotoxicity studies of CP-PLGA nanoparticles against SiHa cancer cells indicated that low concentrations of the nanoparticles were non-toxic to cells (cell viability >80%). From the various formulations studied, 0.05CP-PLGA nanoparticles proved to be the optimum model carrier having the required mucoadhesive profile and could be an alternative therapeutic efficacy carrier for targeted mucosal drug delivery systems with biodegradable polymer.

  2. PLGA nanoparticles loaded with host defense peptide LL37 promote wound healing.

    PubMed

    Chereddy, Kiran Kumar; Her, Charles-Henry; Comune, Michela; Moia, Claudia; Lopes, Alessandra; Porporato, Paolo E; Vanacker, Julie; Lam, Martin C; Steinstraesser, Lars; Sonveaux, Pierre; Zhu, Huijun; Ferreira, Lino S; Vandermeulen, Gaëlle; Préat, Véronique

    2014-11-28

    Wound treatment remains one of the most prevalent and economically burdensome healthcare issues in the world. Poly (lactic-co-glycolic acid) (PLGA) supplies lactate that accelerates neovascularization and promotes wound healing. LL37 is an endogenous human host defense peptide that modulates wound healing and angiogenesis and fights infection. Hence, we hypothesized that the administration of LL37 encapsulated in PLGA nanoparticles (PLGA-LL37 NP) promotes wound closure due to the sustained release of both LL37 and lactate. In full thickness excisional wounds, the treatment with PLGA-LL37 NP significantly accelerated wound healing compared to PLGA or LL37 administration alone. PLGA-LL37 NP-treated wounds displayed advanced granulation tissue formation by significant higher collagen deposition, re-epithelialized and neovascularized composition. PLGA-LL37 NP improved angiogenesis, significantly up-regulated IL-6 and VEGFa expression, and modulated the inflammatory wound response. In vitro, PLGA-LL37 NP induced enhanced cell migration but had no effect on the metabolism and proliferation of keratinocytes. It displayed antimicrobial activity on Escherichia coli. In conclusion, we developed a biodegradable drug delivery system that accelerated healing processes due to the combined effects of lactate and LL37 released from the nanoparticles.

  3. PLGA nanometer surface features manipulate fibronectin interactions for improved vascular cell adhesion.

    PubMed

    Miller, Derick C; Haberstroh, Karen M; Webster, Thomas J

    2007-06-01

    The largest cause of mortality in the Western world is atherosclerotic vascular disease. Many of these diseases require synthetic vascular grafts; however, their patency rate is only 30% in small (<6 mm) diameter vascular grafts after 5 years of implantation. In an effort to increase small diameter vascular graft success, researchers have been designing random nanostructured surface features which enhance vascular cell functions. However, for the present study, highly-controllable, nanostructured features on poly(lactic-co-glycolic acid) (PLGA) surfaces were formulated. To create ordered nanostructured roughness on PLGA surfaces, either 500, 200, or 100 nm polystyrene nanospheres were separately placed onto mica. These were then used as a template for creating an inverse poly(dimethylsiloxane) mold which was utilized to cast PLGA. Compared to all other PLGA films formulated, AFM results demonstrated greater initial fibronectin spreading on PLGA which possessed spherical 200 nm features. Compared to smooth PLGA, PLGA with 500 or 100 nm surface features, results further showed that PLGA with 200 nm spherical features promoted vascular cell (specifically, endothelial, and smooth muscle cell) adhesion. In this manner, the present study demonstrated a specific nanometer surface feature size that promoted fibronectin spreading and subsequent vascular cell adhesion; criteria critical to vascular graft success.

  4. Preparation, characterization, and anticancer efficacy of evodiamine-loaded PLGA nanoparticles.

    PubMed

    Zou, Lidi; Chen, Fengqian; Bao, Jiaolin; Wang, Shengpeng; Wang, Lu; Chen, Meiwan; He, Chengwei; Wang, Yitao

    2016-01-01

    Evodiamine (EVO) is a plant-derived indolequinazoline alkaloid with potential anticancer activity. However, low bioavailability caused by its poor water solubility limits it anticancer efficacy in clinic. To enhance the solubility and improve the bioavailability of EVO, a delivery system based on poly (lactic-co-glycolic acid) (PLGA) nanoparticles loaded with EVO (EVO-PLGA NPs) for treating breast cancer was prepared in this study. The physicochemical characterization and in vitro antitumor evaluation of EVO-PLGA NPs were determined. EVO-PLGA NPs could persistently control the release of EVO for 180 h. 3-[4,5-Dimethyl-2-thiazolyl]-2,5-diphenyl tetrazolium bromide (MTT) assessment and colony formation assay showed that EVO-PLGA NPs could enhance the toxicity and the proliferation inhibition effect of EVO on MCF-7 breast cancer cells. EVO-PLGA NPs did not strengthen G2/M arrest effect of EVO-treated cells after 24h incubation. Meanwhile, EVO-PLGA NPs could increase the expression of cyclin B1 and decrease the expression of β-actin. Taken together, these results suggested that -PLGA NPs is promising for improving anticancer efficacy of EVO in breast cancer therapy.

  5. Biodegradable microparticles and fiber fabrics for sustained delivery of cisplatin to treat C6 glioma in vitro.

    PubMed

    Xie, Jingwei; Tan, Ruo Shan; Wang, Chi-Hwa

    2008-06-15

    The duration of cisplatin release from most of the drug delivery devices seemed to be shorter than 14 days except large microparticles. The objective of this study was to fabricate and characterize cisplatin-loaded PLA microparticles, PLA/PLGA (30/70) composite microparticles, and fibers as formulations for long-term sustained delivery of cisplatin to treat C6 glioma in vitro by electrospray and electrospinning techniques. Cisplatin-loaded biodegradable microparticles with particle size of around 5 microm and fiber fabrics with diameter of 0.5-1.7 microm were obtained using electrospray and electrospinning techniques. Encapsulation efficiency and in vitro release of formulations were measured by ICP-OES. The encapsulation efficiency for different samples of microparticles was approximately from 33% to 72% and the fiber fabrics had encapsulation efficiency greater than 90%. Cisplatin-loaded microparticles showed typical characteristics of cisplatin release profile: a large initial burst followed by a sustained slow release of 35 days. The composite PLA/PLGA (30/70) microparticles could reduce the initial burst release of cisplatin because of their core-shell structures. In contrast, more than 75 days sustained release could be achieved by fiber fabric formulations without large initial burst. MTT assay was used to quantify the cytotoxicity of different formulations against C6 glioma cells. Microparticle formulations had slightly higher cytotoxicity than free drug. In contrast, the cytotoxicity of fiber fabrics formulation was around 4 times higher than of the free drug based on the actual amount of drug released. The microparticle and fiber fabric formulations presented may be promising for the sustained delivery of cisplatin to eliminate the undesired side effects caused by direct injection of cisplatin solution in systemic administration.

  6. Uniform biodegradable microparticle systems for controlled release

    PubMed Central

    Xia, Yujie; Pack, Daniel W.

    2014-01-01

    Drug delivery methods can impact efficacy as much as the nature of the drug itself. Microparticles made of biodegradable polymers such as poly(D,L-lactide-co-glycolide) and poly(lactic acid) (PLA) have been studied extensively for controlled release of diverse drugs. By using a modified solvent extraction/evaporation method called precision particle fabrication (PPF), uniform microparticles such as single-wall microspheres, double-wall microspheres and liquid-core microcapsules have been fabricated with precise control of their geometric structures. By producing particles of uniform size, which has crucial impact on drug release behaviors, PPF-fabricated microparticles provide unique insights about drug release mechanism. Using small-molecule and macromolecule model drugs, our group demonstrated that physicochemical properties of the polymers and drugs and structural properties of the matrix can greatly impact drug distribution within microparticles, particle erosion and drug release rates. By careful selection of particle size and shell thickness, uniform microparticles can achieve “zero-order”, pulsatile or tandem release of drugs. PMID:12106984

  7. Microparticle Flow Sensor

    NASA Technical Reports Server (NTRS)

    Morrison, Dennis R.

    2005-01-01

    The microparticle flow sensor (MFS) is a system for identifying and counting microscopic particles entrained in a flowing liquid. The MFS includes a transparent, optoelectronically instrumented laminar-flow chamber (see figure) and a computer for processing instrument-readout data. The MFS could be used to count microparticles (including micro-organisms) in diverse applications -- for example, production of microcapsules, treatment of wastewater, pumping of industrial chemicals, and identification of ownership of liquid products.

  8. Development of Risperidone PLGA Microspheres

    PubMed Central

    D'Souza, Susan; Faraj, Jabar A.; Giovagnoli, Stefano; DeLuca, Patrick P.

    2014-01-01

    The aim of this study was to design and evaluate biodegradable PLGA microspheres for sustained delivery of Risperidone, with an eventual goal of avoiding combination therapy for the treatment of schizophrenia. Two PLGA copolymers (50 : 50 and 75 : 25) were used to prepare four microsphere formulations of Risperidone. The microspheres were characterized by several in vitro techniques. In vivo studies in male Sprague-Dawley rats at 20 and 40 mg/kg doses revealed that all formulations exhibited an initial burst followed by sustained release of the active moiety. Additionally, formulations prepared with 50 : 50 PLGA had a shorter duration of action and lower cumulative AUC levels than the 75 : 25 PLGA microspheres. A simulation of multiple dosing at weekly or 15-day regimen revealed pulsatile behavior for all formulations with steady state being achieved by the second dose. Overall, the clinical use of Formulations A, B, C, or D will eliminate the need for combination oral therapy and reduce time to achieve steady state, with a smaller washout period upon cessation of therapy. Results of this study prove the suitability of using PLGA copolymers of varying composition and molecular weight to develop sustained release formulations that can tailor in vivo behavior and enhance pharmacological effectiveness of the drug. PMID:24616812

  9. Preparation, characterization and in vivo evaluation of a combination delivery system based on hyaluronic acid/jeffamine hydrogel loaded with PHBV/PLGA blend nanoparticles for prolonged delivery of Teriparatide.

    PubMed

    Bahari Javan, Nika; Montazeri, Hamed; Rezaie Shirmard, Leila; Jafary Omid, Nersi; Barbari, Ghullam Reza; Amini, Mohsen; Ghahremani, Mohammad Hossein; Rafiee-Tehrani, Morteza; Abedin Dorkoosh, Farid

    2017-04-01

    In the current study, biodegradable PHBV/PLGA blend nanoparticles (NPs) containing Teriparatide were loaded in hyaluronic acid/jeffamine (HA-JEF ED-600) hydrogel to prepare a combination delivery system (CDS) for prolonged delivery of Teriparatide. The principal purpose of the present study was to formulate an effective and prolonged Teriparatide delivery system in order to reduce the frequency of injection and thus enhance patient's compliance. Morphological properties, swelling behaviour, crosslinking efficiency and rheological characterization of HA-JEF ED-600 hydrogel were evaluated. The CDS was acquired by adding PHBV/PLGA NPs to HA-JEF ED-600 hydrogel simultaneously with crosslinking reaction. The percentage of NPs incorporation within the hydrogel as well as the loading capacity and morphology of Teriparatide loaded CDS were examined. Intrinsic fluorescence and circular dichroism spectroscopy proved that Teriparatide remains stable after processing. The release profile represented 63% Teriparatide release from CDS within 50days with lower burst release compared to NPs and hydrogel. MTT assay was conducted by using NIH3T3 cell line and no sign of reduction in cell viability was observed. Based on Miller and Tainter method, LD50 of Teriparatide loaded CDS was 131.8mg/kg. In vivo studies demonstrated that Teriparatide loaded CDS could effectively increase serum calcium level after subcutaneous injection in mice. Favourable results in the current study introduced CDS as a promising candidate for controlled delivery of Teriparatide and pave the way for future investigations in the field of designing prolonged delivery systems for other peptides and proteins.

  10. Spray drying of siRNA-containing PLGA nanoparticles intended for inhalation.

    PubMed

    Jensen, Ditte Marie Krohn; Cun, Dongmei; Maltesen, Morten Jonas; Frokjaer, Sven; Nielsen, Hanne Mørck; Foged, Camilla

    2010-02-25

    Local delivery of small interfering RNA (siRNA) to the lungs constitutes a promising new area in drug delivery. The present study evaluated parameters of importance for spray drying of siRNA-loaded poly(D,L-lactide-co-glycolide) (PLGA) nanoparticles (NPs) into nanocomposite microparticles intended for inhalation. The spray drying process was optimised using a statistical design of experiment and by evaluating powder characteristics upon systematic variation of the formulation parameters. Concentration, carbohydrate excipient (trehalose, lactose and mannitol) and the ratio of NP to excipient were varied to monitor the effects on moisture content, particle morphology, particle size and powder yield. The identified optimum conditions were applied for spray drying of siRNA-loaded nanocomposite microparticles, resulting in a product with a low water content (0.78% w/w) and an aerodynamic particle diameter considered suitable for inhalation. The use of mannitol in the formulation allowed a significantly lower moisture content than trehalose and lactose. The inclusion of 50% (w/w) or higher amounts of NPs resulted in a marked change in the surface morphology of the spray-dried particles. Importantly, the integrity and biological activity of the siRNA were preserved during the spray drying process. In conclusion, the present results show that spray drying is a suitable technique for producing nanocomposite microparticles comprising siRNA-containing PLGA NPs for potential use in inhalation therapy.

  11. Melatonin releasing PLGA micro/nanoparticles and their effect on osteosarcoma cells.

    PubMed

    Altındal, Damla Çetin; Gümüşderelioğlu, Menemşe

    2016-02-01

    Melatonin loaded poly(D,L-lactide-co-glycolide) (PLGA) nanoparticles and microparticles in the diameter of ∼200 nm and 3.5 μm, respectively, were prepared by emulsion-diffusion-evaporation method. Melatonin entrapment into the particles was significantly improved with the addition of 0.2% (w/v) melatonin into the aqueous phase and encapsulation efficiencies were found as 14 and 27% for nanoparticles and microparticles, respectively. At the end of 40 days, ∼70% of melatonin was released from both of particles, with high burst release. Both blank and melatonin loaded PLGA nanoparticles caused toxic effect on the MG-63 cells due to their uptake by the cells. However, when 0.05 mg microparticle that is carrying ∼1.7 μg melatonin was added to the cm(2) of culture, inhibitory effect of melatonin on the cells were obviously observed. The results would provide an expectation about the usage of melatonin as an adjunct to the routine chemotherapy of osteosarcoma by encapsulating it into a polymeric carrier system.

  12. Investigation on the ion pair amphiphiles and their in vitro release of amantadine drug based on PLGA-PEG-PLGA gel

    NASA Astrophysics Data System (ADS)

    Yang, Xiaoxia; Ji, Xiaoqing; Shi, Chunhuan; Liu, Jing; Wang, Haiyang; Luan, Yuxia

    2014-12-01

    The amantadine drug and oleic acid surfactant are used to form amantadine-based ion pair amphiphiles based on proton transfer reaction between the drug and the surfactant molecules. The ion pair amphiphiles are characterized by 1H-nuclear magnetic resonance, Fourier transform infrared spectroscopy, and X-ray diffraction. Self-assembly properties of amantadine-based ion pair amphiphiles are studied by surface tension determination, transmission electron microscopy, zeta potential, and dynamic light scattering. The aggregation behavior studies indicate that the as-prepared ion pair amphiphiles can self-assemble into vesicles with the size of 200-300 nm in aqueous solution. The drug release results show that the amantadine release rate could be well controlled by incorporating the amantadine-based ion pair vesicles in poly (lactic-co-glycolic acid)-poly (ethylene glycol)-poly (lactic-co-glycolic acid) (PLGA-PEG-PLGA) copolymer hydrogel. The drug release from the AT-OA vesicle-loaded PLGA-PEG-PLGA hydrogel is significantly inhibited in comparison with the AT-loaded PLGA-PEG-PLGA hydrogel. The present work thus demonstrates that the vesicle-loaded hydrogel is a good candidate for the drug delivery system with long-term controlled drug release behavior.

  13. [Transport of mPEG-PLGA nanoparticles across the rat nasal mucosa].

    PubMed

    Wang, Jun-Teng; Lin, Dong-Hai; Qin, Li-Fang; Wen, Zhen; Guo, Gui-Ping

    2013-05-01

    To investigate the effects of particle size, mPEG molecular weight, coating density and zeta potential of monomethoxyl poly(ethylene glycol)-poly(lactic-co-glycolic acid) (mPEG-PLGA) nanoparticles on their transportation across the rat nasal mucosa, mPEG-PLGA-NPs with different mPEG molecular weights (M(r) 1 000, 2 000) and coating density (0, 5%, 10%, 15%) and chitosan coated PLGA-NP, which loaded coumarin-6 as fluorescent marker, were prepared with the nanoprecipitation method and emulsion-solvent evaporation method, and determine their particle size, zeta potential, the efficiency of fluorescent labeling, in vitro leakage rate and the stability with the lysozyme were determined. The effects of physical and chemical properties on the transmucosal transport of the fluorescent nanoparticles were investigated by confocal laser scanning microscopy (CLSM). The result showed that the size of nanoparticles prepared with nanoprecipitation method varied between 120 and 200 nm; the size of nanoparticles prepared with emulsion-solvent evaporation method varied between 420 and 450 nm. Nanoparticles dispersed uniformly; the zeta potential of PLGA-NPs was negative; mPEG-PLGA-NPs was close to neutral; chitosan coated PLGA-NPs was positive; and the efficiency of fluorescent labeling were higher than 80%. In vitro leak was less than 5% within 4 h and nanoparticles were basically stable with lysozyme. The CLSM results show that the transportation efficiency of mPEG-PLGA-NPs with a high PEG coating density and high mPEG molecular weight was significantly higher than that of uncoated PLGA nanoparticles and also that of chitosan coated PLGA-NPs (P < 0.05). The hydrophilcity, zeta potential and particle size of nanoparticles play important roles on the efficiency of mPEG-PLGA nanoparticles to transport across the rat nasal mucosa.

  14. Influence of PEI as a Core Modifying Agent on PLGA Microspheres of PGE1, A Pulmonary Selective Vasodilator

    PubMed Central

    Gupta, Vivek; Ahsan, Fakhrul

    2011-01-01

    This study tests the hypothesis that large porous poly (lactic-co-glycolic acid) (PLGA) microparticles modified with polyethyleneimine (PEI) are viable carriers for pulmonary delivery of prostaglandin E1 (PGE1) used in the treatment of pulmonary arterial hypertension (PAH), a pulmonary vascular disorder. The particles were prepared by a double-emulsion solvent evaporation method with PEI-25 kDa in the internal aqueous phase to produce an osmotic pressure gradient. Polyvinyl alcohol (PVA) was used for external coating of the particles. The particles were examined for morphology, size, aerodynamic diameter, surface area, pore volume and in-vitro release profiles. Particles with optimal properties for inhalation were tested for in-vivo pulmonary absorption, metabolic stability in rat lung homogenates, and acute toxicity in rat bronchoalveolar lavage fluid and respiratory epithelial cells, Calu-3. The micromeritic data indicated that the PEI-modified particles of PGE1 are optimal for inhalation. Incorporation of PEI in the formulations resulted in an increased entrapment efficiency–83.26±3.04% for particles with 1% PVA and 95.48±0.46% for particles with 2% PVA. The amount of cumulative drug released into the simulated interstitial lung fluid was between 50.8±0.76% and 55.36±0.06%. A remarkable extension of the circulation half-life up to 6.0–6.5 hours was observed when the formulations were administered via the lungs. The metabolic stability and toxicity studies showed that the optimized formulations were stable at physiological conditions and relatively safe to the lungs and respiratory epithelium. Overall, this study demonstrates that large porous inhalable polymeric microparticles can be a feasible option for non-invasive and controlled release of PGE1 for treatment of PAH. PMID:21530623

  15. PLGA nanofiber membranes loaded with epigallocatechin-3-O-gallate are beneficial to prevention of postsurgical adhesions

    PubMed Central

    Shin, Yong Cheol; Yang, Won Jun; Lee, Jong Ho; Oh, Jin-Woo; Kim, Tai Wan; Park, Jong-Chul; Hyon, Suong-Hyu; Han, Dong-Wook

    2014-01-01

    This study concentrates on the development of biodegradable nanofiber membranes with controlled drug release to ensure reduced tissue adhesion and accelerated healing. Nanofibers of poly(lactic-co-glycolic acid) (PLGA) loaded with epigallocatechin-3-O-gallate (EGCG), the most bioactive polyphenolic compound in green tea, were electrospun. The physicochemical and biomechanical properties of EGCG-releasing PLGA (E-PLGA) nanofiber membranes were characterized by atomic force microscopy, EGCG release and degradation profiles, and tensile testing. In vitro antioxidant activity and hemocompatibility were evaluated by measuring scavenged reactive oxygen species levels and activated partial thromboplastin time, respectively. In vivo antiadhesion efficacy was examined on the rat peritonea with a surgical incision. The average fiber diameter of E-PLGA membranes was approximately 300–500 nm, which was almost similar to that of pure PLGA equivalents. E-PLGA membranes showed sustained EGCG release mediated by controlled diffusion and PLGA degradation over 28 days. EGCG did not adversely affect the tensile strength of PLGA membranes, whereas it significantly decreased the elastic modulus and increased the strain at break. E-PLGA membranes were significantly effective in both scavenging reactive oxygen species and extending activated partial thromboplastin time. Macroscopic observation after 1 week of surgical treatment revealed that the antiadhesion efficacy of E-PLGA nanofiber membranes was significantly superior to those of untreated controls and pure PLGA equivalents, which was comparable to that of a commercial tissue-adhesion barrier. In conclusion, the E-PLGA hybrid nanofiber can be exploited to craft strategies for the prevention of postsurgical adhesions. PMID:25187710

  16. PLGA nanofiber membranes loaded with epigallocatechin-3-O-gallate are beneficial to prevention of postsurgical adhesions.

    PubMed

    Shin, Yong Cheol; Yang, Won Jun; Lee, Jong Ho; Oh, Jin-Woo; Kim, Tai Wan; Park, Jong-Chul; Hyon, Suong-Hyu; Han, Dong-Wook

    2014-01-01

    This study concentrates on the development of biodegradable nanofiber membranes with controlled drug release to ensure reduced tissue adhesion and accelerated healing. Nanofibers of poly(lactic-co-glycolic acid) (PLGA) loaded with epigallocatechin-3-O-gallate (EGCG), the most bioactive polyphenolic compound in green tea, were electrospun. The physicochemical and biomechanical properties of EGCG-releasing PLGA (E-PLGA) nanofiber membranes were characterized by atomic force microscopy, EGCG release and degradation profiles, and tensile testing. In vitro antioxidant activity and hemocompatibility were evaluated by measuring scavenged reactive oxygen species levels and activated partial thromboplastin time, respectively. In vivo antiadhesion efficacy was examined on the rat peritonea with a surgical incision. The average fiber diameter of E-PLGA membranes was approximately 300-500 nm, which was almost similar to that of pure PLGA equivalents. E-PLGA membranes showed sustained EGCG release mediated by controlled diffusion and PLGA degradation over 28 days. EGCG did not adversely affect the tensile strength of PLGA membranes, whereas it significantly decreased the elastic modulus and increased the strain at break. E-PLGA membranes were significantly effective in both scavenging reactive oxygen species and extending activated partial thromboplastin time. Macroscopic observation after 1 week of surgical treatment revealed that the antiadhesion efficacy of E-PLGA nanofiber membranes was significantly superior to those of untreated controls and pure PLGA equivalents, which was comparable to that of a commercial tissue-adhesion barrier. In conclusion, the E-PLGA hybrid nanofiber can be exploited to craft strategies for the prevention of postsurgical adhesions.

  17. Improving Protein Stability and Controlling Protein Release by Adding Poly (Cyclohexane-1, 4-Diyl Acetone Dimethylene Ketal) to PLGA Microspheres.

    PubMed

    Wang, Chenhui; Yu, Changhui; Yu, Kongtong; Teng, Lesheng; Liu, Jiaxin; Wang, Xuesong; Sun, Fengying; Li, Youxin

    2015-01-01

    The use of biodegradable polymers such as PLGA to encapsulate therapeutic proteins for their controlled release has received tremendous interest. However, an acidic environment caused by PLGA degradation productions leads to protein incomplete release and chemical degradation. The aim of this study was to develop novel PCADK/PLGA microspheres to improve protein stability and release behavior. Bovine serum albumin (BSA) incubated in PCADK and PLGA degradation products was investigated using sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), size exclusion chromatography (SEC-HPLC), circular dichroism (CD) and fluorescence spectroscopy. Blended microspheres of PCADK/PLGA were prepared in different ratios and the release behaviors of the microspheres and the protein stability were then measured. The degradation properties of the microspheres and the pH inside the microspheres were systematically investigated by scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM) to examine the mechanism of autocatalytic degradation and protein stability. BSA was more stable in the presence of PCADK monomers than it was in the presence of PLGA monomers, revealing that PCADK is highly compatible with this protein. PCADK/PLGA microspheres were successfully prepared, and 2/8 was determined to be the optimal ratio. Further, 43% of the BSA formed water-insoluble aggregates in the presence of PCADK/PLGA microspheres, compared with 57% for the PLGA microspheres, demonstrating that the BSA encapsulated in PCADK/PLGA blended microspheres was more stable than in PLGA microspheres. The PCADK/PLGA blended microspheres improved protein stability and release behavior, providing a promising protein drug delivery system.

  18. Efficient production of retroviruses using PLGA/bPEI-DNA nanoparticles and application for reprogramming somatic cells.

    PubMed

    Seo, Eun Jin; Jang, Il Ho; Do, Eun Kyoung; Cheon, Hyo Cheon; Heo, Soon Chul; Kwon, Yang Woo; Jeong, Geun Ok; Kim, Ba Reun; Kim, Jae Ho

    2013-01-01

    Reprogramming of somatic cells to pluripotent cells requires the introduction of factors driving fate switches. Viral delivery has been the most efficient method for generation of induced pluripotent stem cells. Transfection, which precedes virus production, is a commonly-used process for delivery of nucleic acids into cells. The aim of this study is to evaluate the efficiency of PLGA/ bPEI nanoparticles in transfection and virus production. Using a modified method of producing PLGA nanoparticles, PLGA/bPEI-DNA nanoparticles were examined for transfection efficiency and virus production yield in comparison with PLGA-DNA, bPEI-DNA nanoparticles or liposome-DNA complexes. After testing various ratios of PLGA, bPEI, and DNA, the ratio of 6:3:1 (PLGA:bPEI:DNA, w/w/w) was determined to be optimal, with acceptable cellular toxicity. PLGA/bPEI-DNA (6:3:1) nanoparticles showed superior transfection efficiency, especially in multiple gene transfection, and viral yield when compared with liposome-DNA complexes. The culture supernatants of HEK293FT cells transfected with PLGA/bPEI-DNA of viral constructs containing reprogramming factors (Oct4, Sox2, Klf4, or c-Myc) successfully and more efficiently generated induced pluripotent stem cell colonies from mouse embryonic fibroblasts. These results strongly suggest that PLGA/bPEI-DNA nanoparticles can provide significant advantages in studying the effect of multiple factor delivery such as in reprogramming or direct conversion of cell fate.

  19. Differential permeation of piroxicam-loaded PLGA micro/nanoparticles and their in vitro enhancement

    NASA Astrophysics Data System (ADS)

    Shankarayan, Raju; Kumar, Sumit; Mishra, Prashant

    2013-03-01

    Piroxicam is a non-steroidal anti-inflammatory drug used for the treatment of musculoskeletal pain. The main problem encountered when piroxicam is administered orally is its gastric side-effect (ulcer, bleeding and holes in the stomach). Transmucosal delivery and encapsulation of piroxicam in biodegradable particles offer potential advantages over conventional oral delivery. The present study was aimed to develop an alternative to piroxicam-delivery which could overcome the direct contact of the drug at the mucosal membrane and its permeation through the mucosal membrane was studied. To achieve this, the piroxicam was encapsulated in Poly (lactide- co-glycolide) (PLGA) microparticles (size 1-4 μm, encapsulation efficiency 80-85 %) and nanoparticles (size 151.6 ± 28.6 nm, encapsulation efficiency 92.17 ± 3.08 %). Various formulation process parameters were optimised for the preparation of piroxicam-loaded PLGA nanoparticles of optimal size and encapsulation efficiency. Transmucosal permeability of piroxicam-loaded PLGA micro- and nanoparticles through the porcine oesophageal mucosa was studied. Using fluorescently labelled PLGA micro- and nanoparticles, size-dependent permeation was demonstrated. Furthermore, the effect of different permeation enhancers on the flux rate and permeability coefficient for the permeation of nanoparticles was investigated. The results suggested that amongst the permeation enhancers used the most efficient enhancement of permeation was observed with 10 mM sodium dodecyl sulphate.

  20. Injectable Sustained Release Microparticles of Curcumin: A New Concept for Cancer Chemoprevention

    PubMed Central

    Shahani, Komal; Swaminathan, Suresh Kumar; Freeman, Diana; Blum, Angela; Ma, Linan; Panyam, Jayanth

    2010-01-01

    Poor oral bioavailability limits the use of curcumin and other dietary polyphenols in the prevention and treatment of cancer. Minimally invasive strategies that can provide effective and sustained tissue concentrations of these agents will be highly valuable tools in the fight against cancer. The objective of this study was to investigate the use of an injectable sustained release microparticle formulation of curcumin as a novel approach to breast cancer chemoprevention. A biodegradable and biocompatible polymer, poly(D,L-lactide-co-glycolide) (PLGA), was used to fabricate curcumin microparticles. When injected subcutaneously in mice, a single dose of microparticles sustained curcumin levels in the blood and other tissues for nearly a month. Curcumin levels in the lungs and brain, frequent sites of breast cancer metastases, were 10-30-fold higher than that in the blood. Further, curcumin microparticles showed marked anticancer efficacy in nude mice bearing MDA-MB-231 xenografts compared to other controls. Repeated systemic injections of curcumin were not effective in inhibiting tumor growth. Treatment with curcumin microparticles resulted in diminished VEGF expression and poorly developed tumor microvessels, indicating a significant effect on tumor angiogenesis. These results suggest that sustained delivery of chemopreventives such as curcumin using polymeric microparticles is a promising new approach to cancer chemoprevention and therapy. PMID:20460537

  1. Biodegradable microparticles with surface dimples as a bi-modal imaging contrast agent.

    PubMed

    Kim, Mi Ri; Lim, Yong Taik; Cho, Kuk Young

    2013-03-12

    Fabrication of physically engineered colloids and their application to the biological fields is emerging importance because of their potential to provide an enhanced performance without altering the chemical properties of biomaterials used. A facile approach is reported to fabricate sub-10-μm-sized PLGA microparticle with small dimples covering the surface by droplet imprinting. Optical and magnetic resonance bioimaging agents are easily co-encapsulated inside the microparticles to obtain a bi-modal imaging agent. Cell internalization efficacy of dimpled particles in DC 2.4 cell is enhanced compared with conventional smooth round-shaped colloids. Our result indicates that morphology-controlled microparticles show promise as a cell labeling with improved cell interaction.

  2. Preparation and characterization of gadolinium-loaded PLGA particles surface modified with RGDS for the detection of thrombus

    PubMed Central

    Zhang, Yu; Zhou, Jun; Guo, Dajing; Ao, Meng; Zheng, Yuanyi; Wang, Zhigang

    2013-01-01

    Thrombotic disease is a leading cause of death and disability worldwide. The development of magnetic resonance molecular imaging provides potential promise for early disease diagnosis. In this study, we explore the preparation and characterization of gadolinium (Gd)-loaded poly (lactic-co-glycolic acid) (PLGA) particles surface modified with the Arg-Gly-Asp-Ser (RGDS) peptide for the detection of thrombus. PLGA was employed as the carrier-delivery system, and a double emulsion solvent-evaporation method (water in oil in water) was used to prepare PLGA particles encapsulating the magnetic resonance contrast agent Gd diethylenetriaminepentaacetic acid (DTPA). To synthesize the Gd-PLGA/chitosan (CS)-RGDS particles, carbodiimide-mediated amide bond formation was used to graft the RGDS peptide to CS to form a CS-RGDS film that coated the surface of the PLGA particles. Blank PLGA, Gd-PLGA, and Gd-PLGA/CS particles were fabricated using the same water in oil in water method. Our results indicated that the RGDS peptide successfully coated the surface of the Gd-PLGA/CS-RGDS particles. The particles had a regular shape, smooth surface, relatively uniform size, and did not aggregate. The high electron density of the Gd-loaded particles and a translucent film around the particles coated with the CS and CS-RGDS films could be observed by transmission electron microscopy. In vitro experiments demonstrated that the Gd-PLGA/CS-RGDS particles could target thrombi and could be imaged using a clinical magnetic resonance scanner. Compared with the Gd-DTPA solution, the longitudinal relaxation time of the Gd-loaded particles was slightly longer, and as the Gd-load concentration increased, the longitudinal relaxation time values decreased. These results suggest the potential of the Gd-PLGA/CS-RGDS particles for the sensitive and specific detection of thrombus at the molecular level. PMID:24124363

  3. In vitro evaluation of the genotoxicity of a family of novel MeO-PEG-poly(D,L-lactic-co-glycolic acid)-PEG-OMe triblock copolymer and PLGA nanoparticles

    NASA Astrophysics Data System (ADS)

    He, Lili; Yang, Likai; Zhang, Zhi-rong; Gong, Tao; Deng, Li; Gu, Zhongwei; Sun, Xun

    2009-11-01

    Despite the booming development of nanoparticle materials for pharmaceutical applications, studies on their genotoxicity are few. In our previous efforts to develop an intravenous nanoparticle material, a family of novel monomethoxy(polyethylene glycol)-poly(D,L-lactic-co-glycolic acid)-monomethoxy (PELGE) polymers was synthesized. The cytotoxicity and genotoxicity of nine kinds of selected blank PELGE and PLGA (poly(D,L-lactic and glycolic acid)) nanoparticles were evaluated using methyl thiazolyl tetrazolium (MTT), micronucleus (MN) and sister chromatid exchange (SCE) assays with or without the addition of a metabolic activation system (S9 mix), using Chinese hamster ovary (CHO) cells. The cytotoxicity of nanoparticles exhibited a dose-dependent response, with a concentration of 5 mg ml-1 being the turning point. The frequencies of MN observed in samples treated with various nanoparticles were not statistically different from those seen in the negative controls in the presence or absence of the S9 mix. Also, no cell cycle delay was observed. The numbers of SCE per cell observed in samples treated with five kinds of PELGE nanoparticles were significantly greater than those found in the negative controls with or without the S9 mix. The discrepancies found in the two assays suggest that the five kinds of nanoparticles may produce only a weakly clastogenic response.

  4. Assessment of PLGA-PEG-PLGA copolymer hydrogel for sustained drug delivery in the ear.

    PubMed

    Feng, Liang; Ward, Jonette A; Li, S Kevin; Tolia, Gaurav; Hao, Jinsong; Choo, Daniel I

    2014-01-01

    Temperature sensitive copolymer systems were previously studied using modified diffusion cells in vitro for intratympanic injection, and the PLGA-PEG-PLGA copolymer systems were found to provide sustained drug delivery for several days. The objectives of the present study were to assess the safety of PLGA-PEG-PLGA copolymers in intratympanic injection in guinea pigs in vivo and to determine the effects of additives glycerol and poloxamer in PLGA-PEGPLGA upon drug release in the diffusion cells in vitro for sustained inner ear drug delivery. In the experiments, the safety of PLGA-PEG-PLGA copolymers to inner ear was evaluated using auditory brainstem response (ABR). The effects of the additives upon drug release from PLGA-PEG-PLGA hydrogel were investigated in the modified Franz diffusion cells in vitro with cidofovir as the model drug. The phase transition temperatures of the PLGA-PEG-PLGA copolymers in the presence of the additives were also determined. In the ABR safety study, the PLGA-PEG-PLGA copolymer alone did not affect hearing when delivered at 0.05-mL dose but caused hearing loss after 0.1-mL injection. In the drug release study, the incorporation of the bioadhesive additive, poloxamer, in the PLGA-PEG-PLGA formulations was found to decrease the rate of drug release whereas the increase in the concentration of the humectant additive, glycerol, provided the opposite effect. In summary, the PLGA-PEG-PLGA copolymer did not show toxicity to the inner ear at the 0.05-mL dose and could provide sustained release that could be controlled by using the additives for inner ear applications.

  5. Sinonasal Delivery of Resveratrol via Mucoadhesive Nanostructured Microparticles in a Nasal Polyp Mouse Model

    PubMed Central

    Lee, Mingyu; Park, Chun Gwon; Huh, Beom Kang; Kim, Se-Na; Lee, Seung Ho; Khalmuratova, Roza; Park, Jong-Wan; Shin, Hyun-Woo; Choy, Young Bin

    2017-01-01

    Resveratrol (RSV) has been shown to effectively suppress chronic rhinosinusitis with nasal polyps in a mouse model; however, when locally administered to the sinonasal cavity, bolus RSV is limited by low drug bioavailability owing to its low aqueous solubility and relatively rapid clearance from the administration site. To address this limitation, we propose mucoadhesive nanostructured microparticles (PLGA/PEG NM) as a potential carrier for the sinonasal delivery of RSV. In this study, PLGA/PEG NM released RSV in a sustained manner. Owing to the enlarged specific surface area of the nanostructures, PLGA/PEG NM had synergistically enhanced mucoadhesiveness and thus showed improved in vivo retention properties in the sinonasal cavity. Therefore, when tested in a mouse nasal polyp model, PLGA/PEG NM mitigated polyp formation and restored epithelial integrity better than the control treatments. The therapeutic effect was similar at half the dose of PLGA/PEG NM, suggesting improved local bioavailability of RSV in the sinonasal cavity. PMID:28071713

  6. Bone induction by biomimetic PLGA-(PEG-ASP)n copolymer loaded with a novel synthetic BMP-2-related peptide in vitro and in vivo.

    PubMed

    Lin, Zhen-Yu; Duan, Zhi-Xia; Guo, Xiao-Dong; Li, Jing-Feng; Lu, Hong-Wei; Zheng, Qi-Xin; Quan, Da-Ping; Yang, Shu-Hua

    2010-06-01

    BMP-2 is one of the most important growth factors of bone regeneration. Polylactide-co-glycolic acid (PLGA), which is used as a biodegradable scaffold for delivering therapeutic agents, has been intensively investigated. In previous studies, we synthesized a novel BMP-2-related peptide (designated P24) and found that it could enhance the osteoblastic differentiation of bone marrow stromal cells (BMSCs). The objective of this study was to construct a biomimetic composite by incorporating P24 into a modified PLGA-(PEG-ASP)n copolymer to promote bone formation. In vitro, our results demonstrated that PLGA-(PEG-ASP)n scaffolds were shown to be an efficient system for sustained release of P24. Significantly more BMSCs attached to the P24/PLGA-(PEG-ASP)n and PLGA-(PEG-ASP)n membranes than to PLGA, and the cells in the two groups subsequently proliferated more vigorously than those in the PLGA group. The expression of osteogenic markers in P24/PLGA-(PEG-ASP)n group was stronger than that in the PLGA-(PEG-ASP)n and PLGA groups. Radiographic and histological examination, Western blotting and RT-PCR showed that P24/PLGA-(PEG-ASP)n scaffold could induce more effective ectopic bone formation in vivo, as compared with PLGA-(PEG-ASP)n or gelatin sponge alone. It is concluded that the PLGA-(PEG-ASP)n copolymer is a good P24 carrier and can serve as a good scaffold for controlled release of P24. This novel P24/PLGA-(PEG-ASP)n composite promises to be an excellent biomaterial for inducing bone regeneration.

  7. Microparticle analysis system and method

    NASA Technical Reports Server (NTRS)

    Morrison, Dennis R. (Inventor)

    2007-01-01

    A device for analyzing microparticles is provided which includes a chamber with an inlet and an outlet for respectively introducing and dispensing a flowing fluid comprising microparticles, a light source for providing light through the chamber and a photometer for measuring the intensity of light transmitted through individual microparticles. The device further includes an imaging system for acquiring images of the fluid. In some cases, the device may be configured to identify and determine a quantity of the microparticles within the fluid. Consequently, a method for identifying and tracking microparticles in motion is contemplated herein. The method involves flowing a fluid comprising microparticles in laminar motion through a chamber, transmitting light through the fluid, measuring the intensities of the light transmitted through the microparticles, imaging the fluid a plurality of times and comparing at least some of the intensities of light between different images of the fluid.

  8. Producing xylan/Eudragit® S100-based microparticles by chemical and physico-mechanical approaches as carriers for 5-aminosalicylic acid.

    PubMed

    Silva, Acarilia Eduardo; Oliveira, Elquio Eleamen; Gomes, Monique C Salgado; Marcelino, Henrique Rodrigues; Silva, Karen C Holanda; Souza, Bartolomeu Santos; Nagashima, Toshiyuki; Ayala, Alejandro Pedro; Oliveira, Anselmo Gomes; do Egito, Eryvaldo Sócrates Tabosa

    2013-01-01

    Xylan is a biopolymer found in a variety of cell wall plants. Eudragit® S-100 (ES100), a pH-dependent polymer, is used as a coating material in gastroresistant delivery systems. In this study, microparticles based on both polymers were produced by interfacial cross-linking polymerisation and/or spray-drying technique in order to investigate feasibility and stability of the systems. Size and morphology of the microparticles were characterised by optical and SEM while FT-IR, thermal analysis (TG/DTA), and X-ray diffraction (XRD) evaluated the drug-polymer interactions and the thermal behaviour of the systems. FT-IR confirmed the absence of chemical interaction between the polymers. TG/DTA analysis showed a higher stability for spray-dried microparticles and XRD data proved the amorphous feature of both carriers. The results reveal that xylan/ES100 microparticles can be produced by chemical or physico-mechanical ways, the latter being the best option due to the lack of toxic cross-linking agents and easy scale-up.

  9. Preparation, physicochemical properties and biocompatibility of PBLG/PLGA/bioglass composite scaffolds.

    PubMed

    Cui, Ning; Qian, Junmin; Wang, Jinlei; Ji, Chuanlei; Xu, Weijun; Wang, Hongjie

    2017-02-01

    In this study, novel poly(γ-benzyl l-glutamate)/poly(lactic-co-glycolic acid)/bioglass (PBLG/PLGA/BG) composite scaffolds with different weight ratios were fabricated using a negative NaCl-templating method. The morphology, compression modulus and degradation kinetics of the scaffolds were characterized. The results showed that the PBLG/PLGA/BG composite scaffolds with a weight ratio of 5:5:1, namely PBLG5PLGA5BG composite scaffolds, displayed a pore size range of 50-500μm, high compressive modulus (566.6±8.8kPa), suitable glass transition temperature (46.8±0.2°C) and low degradation rate (>8weeks). The in vitro biocompatibility of the scaffolds was evaluated with MC3T3-E1 cells by live-dead staining, MTT and ALP activity assays. The obtained results indicated that the PBLG5PLGA5BG composite scaffolds were more conducive to the adhesion, proliferation and osteoblastic differentiation of MC3T3-E1 cells than PBLG and PBLG/PLGA composite scaffolds. The in vivo biocompatibility of the scaffolds was evaluated in both SD rat subcutaneous model and rabbit tibia defect model. The results of H&E, Masson's trichrome and CD34 staining assays demonstrated that the PBLG5PLGA5BG composite scaffolds allowed the ingrowth of tissue and microvessels more effectively than PBLG/PLGA composite scaffolds. The results of digital radiography confirmed that the PBLG5PLGA5BG composite scaffolds significantly improved in vivo osteogenesis. Collectively, the PBLG5PLGA5BG composite scaffolds could be a promising candidate for tissue engineering applications.

  10. PLGA-Mesoporous Silicon Microspheres for the in Vivo Controlled Temporospatial Delivery of Proteins.

    PubMed

    Minardi, Silvia; Pandolfi, Laura; Taraballi, Francesca; De Rosa, Enrica; Yazdi, Iman K; Liu, Xeuwu; Ferrari, Mauro; Tasciotti, Ennio

    2015-08-05

    In regenerative medicine, the temporospatially controlled delivery of growth factors (GFs) is crucial to trigger the desired healing mechanisms in the target tissues. The uncontrolled release of GFs has been demonstrated to cause severe side effects in the surrounding tissues. The aim of this study was to optimize a translational approach for the fine temporal and spatial control over the release of proteins, in vivo. Hence, we proposed a newly developed multiscale composite microsphere based on a core consisting of the nanostructured silicon multistage vector (MSV) and a poly(dl-lactide-co-glycolide) acid (PLGA) outer shell. Both of the two components of the resulting composite microspheres (PLGA-MSV) can be independently tailored to achieve multiple release kinetics contributing to the control of the release profile of a reporter protein in vitro. The influence of MSV shape (hemispherical or discoidal) and size (1, 3, or 7 μm) on PLGA-MSV's morphology and size distribution was investigated. Second, the copolymer ratio of the PLGA used to fabricate the outer shell of PLGA-MSV was varied. The composites were fully characterized by optical microscopy, scanning electron microscopy, ζ potential, Fourier transform infrared spectroscopy, and thermogravimetric analysis-differential scanning calorimetry, and their release kinetics over 30 days. PLGA-MSV's biocompatibility was assessed in vitro with J774 macrophages. Finally, the formulation of PLGA-MSV was selected, which concurrently provided the most consistent microsphere size and allowed for a zero-order release kinetic. The selected PLGA-MSVs were injected in a subcutaneous model in mice, and the in vivo release of the reporter protein was followed over 2 weeks by intravital microscopy, to assess if the zero-order release was preserved. PLGA-MSV was able to retain the payload over 2 weeks, avoiding the initial burst release typical of most drug delivery systems. Finally, histological evaluation assessed the

  11. Porous magnesium/PLGA composite scaffolds for enhanced bone regeneration following tooth extraction.

    PubMed

    Brown, Andrew; Zaky, Samer; Ray, Herbert; Sfeir, Charles

    2015-01-01

    Sixty percent of implant-supported dental prostheses require bone grafting to enhance bone quantity and quality prior to implant placement. We have developed a metallic magnesium particle/PLGA composite scaffold to overcome the limitations of currently used dental bone grafting materials. This is the first report of porous metallic magnesium/PLGA scaffolds synthesized using a solvent casting, salt leaching method. We found that incorporation of varying amounts of magnesium into the PLGA scaffolds increased the compressive strength and modulus, as well as provided a porous structure suitable for cell infiltration, as measured by mercury intrusion porosimetry. Additionally, combining basic-degrading magnesium with acidic-degrading PLGA led to an overall pH buffering effect and long-term release of magnesium over the course of a 10-week degradation assay, as measured with inductively coupled plasma-atomic emission spectroscopy. Using an indirect proliferation assay adapted from ISO 10993:5, it was found that extracts of medium from degrading magnesium/PLGA scaffolds increased bone marrow stromal cell proliferation in vitro, a phenomenon observed by other groups investigating magnesium's impact on cells. Finally, magnesium/PLGA scaffold biocompatibility was assessed in a canine socket preservation model. Micro-computed tomography and histological analysis showed the magnesium/PLGA scaffolds to be safer and more effective at preserving bone height than empty controls. Three-dimensional magnesium/PLGA composite scaffolds show promise for dental socket preservation and also, potentially, orthopedic bone regeneration. These scaffolds could decrease inflammation observed with clinically used PLGA devices, as well as enhance osteogenesis, as observed with previously studied magnesium devices.

  12. Surface modification of PLGA nanoparticles via human serum albumin conjugation for controlled delivery of docetaxel

    PubMed Central

    2013-01-01

    Background Poly lactic-co-glycolic acid (PLGA) based nanoparticles are considered to be a promising drug carrier in tumor targeting but suffer from the high level of opsonization by reticuloendothelial system due to their hydrophobic structure. As a result surface modification of these nanoparticles has been widely studied as an essential step in their development. Among various surface modifications, human serum albumin (HSA) possesses advantages including small size, hydrophilic surface and accumulation in leaky vasculature of tumors through passive targeting and a probable active transport into tumor tissues. Methods PLGA nanoparticles of docetaxel were prepared by emulsification evaporation method and were surface conjugated with human serum albumin. Fourier transform infrared spectrum was used to confirm the conjugation reaction where nuclear magnetic resonance was utilized for conjugation ratio determination. In addition, transmission electron microscopy showed two different contrast media in conjugated nanoparticles. Furthermore, cytotoxicity of free docetaxel, unconjugated and conjugated PLGA nanoparticles was studied in HepG2 cells. Results Size, zeta potential and drug loading of PLGA nanoparticles were about 199 nm, −11.07 mV, and 4%, respectively where size, zeta potential and drug loading of conjugated nanoparticles were found to be 204 nm, −5.6 mV and 3.6% respectively. Conjugated nanoparticles represented a three-phasic release pattern with a 20% burst effect for docetaxel on the first day. Cytotoxicity experiment showed that the IC50 of HSA conjugated PLGA nanoparticles (5.4 μg) was significantly lower than both free docetaxel (20.2 μg) and unconjugated PLGA nanoparticles (6.2 μg). Conclusion In conclusion surface modification of PLGA nanoparticles through HSA conjugation results in more cytotoxicity against tumor cell lines compared with free docetaxel and unconjugated PLGA nanoparticles. Albumin conjugated PLGA nanoparticles may

  13. The effect of formulation variables on the characteristics of insulin-loaded poly(lactic-co-glycolic acid) microspheres prepared by a single phase oil in oil solvent evaporation method.

    PubMed

    Hamishehkar, Hamed; Emami, Jaber; Najafabadi, Abdolhossein Rouholamini; Gilani, Kambiz; Minaiyan, Mohsen; Mahdavi, Hamid; Nokhodchi, Ali

    2009-11-01

    Biodegradable polymeric microspheres are ideal vehicles for controlled delivery applications of drugs, peptides and proteins. Amongst them, poly(lactic-co-glycolic acid) (PLGA) has generated enormous interest due to their favorable properties and also has been approved by FDA for drug delivery. Insulin-loaded PLGA microparticles were prepared by our developed single phase oil in oil (o/o) emulsion solvent evaporation technique. Insulin, a model protein, was successfully loaded into microparticles by changing experimental variables such as polymer molecular weight, polymer concentration, surfactant concentration and stirring speed in order to optimize process variables on drug encapsulation efficiency, release rates, size and size distribution. A 2(4) full factorial design was employed to evaluate systematically the combined effect of variables on responses. Scanning electron microscope (SEM) confirmed spherical shapes, smooth surface morphology and microsphere structure without aggregation. FTIR and DSC results showed drug-polymer interaction. The encapsulation efficiency of insulin was mainly influenced by surfactant concentration. Moreover, polymer concentration and polymer molecular weight affected burst release of drug and size characteristics of microspheres, respectively. It was concluded that using PLGA with higher molecular weight, high surfactant and polymer concentrations led to a more appropriate encapsulation efficiency of insulin with low burst effect and desirable release pattern.

  14. Comparative study of kanamycin sulphate microparticles and nanoparticles for intramuscular administration: preparation in vitro release and preliminary in vivo evaluation.

    PubMed

    Mustafa, Sanaul; Devi, V Kusum; Pai, Roopa S

    2016-11-01

    Kanamycin sulphate (KS) is a Mycobacterium tuberculosis protein synthesis inhibitor. KS is polycationic, a property responsible for KS poor oral absorption half-life (2.5 h) and rapid renal clearance, which results in serious nephrotoxicity/ototoxicity. The current study aimed to develop KS-loaded PLGA vitamin-E-TPGS microparticles (MPs) and nanoparticles (NPs) to reduce the dosing frequency and dose-related adverse effect. In vitro release was sustained up to 10 days for KS PLGA-TPGS MPs and 13 days for KS PLGA-TPGS NPs in phosphate-buffered saline (PBS) pH 7.4. The in vivo pharmacokinetic test in Wistar rats showed that the AUC0-∞ of KS PLGA-TPGS NPs (280.58 μg/mL*min) was about 1.62-fold higher than that of KS PLGA-TPGS MPs (172.30 μg/mL*min). Further, in vivo protein-binding assay ascribed 1.20-fold increase in the uptake of KS PLGA-TPGS NPs through the alveolar macrophage (AM). The studies, therefore, could provide another useful tool for successful development of KS MPs and NPs.

  15. Measurement of PLGA-NP interaction with single smooth muscle cells using optical tweezers

    NASA Astrophysics Data System (ADS)

    Gu, Ling; Mondal, Argha; Homayoni, Homa; Nguyen, Kytai; Mohanty, Samarendra

    2012-10-01

    For intervention of cardiovascular diseases, biodegradable and biocompatible, poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NP) are emerging as agents of choice for controlled and targeted drug delivery. Therefore development of PLGA-NP with optimal physico-chemical properties will allow efficient binding and thus delivery of drug to targeted cells under various patho-physiological conditions. The force kinetics and its dependence on size of the NPs will be crucial for designing the NPs. Since optical tweezers allow non-contact, highly sensitive force measurement with high spatial and temporal resolution, we utilized it for studying interaction forces between magnetic PLGA nanoparticles with smooth muscle cells (SMC). In order to investigate effect of size, interaction force for 200 to 1100nm PLGA NP was measured. For similar interaction duration, the force was found to be higher with increase in size. The rupture force was found to depend on time of interaction of SMC with NPs.

  16. In vitro performance of lipid-PLGA hybrid nanoparticles as an antigen delivery system: lipid composition matters

    NASA Astrophysics Data System (ADS)

    Hu, Yun; Ehrich, Marion; Fuhrman, Kristel; Zhang, Chenming

    2014-08-01

    Due to the many beneficial properties combined from both poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NPs) and liposomes, lipid-PLGA hybrid NPs have been intensively studied as cancer drug delivery systems, bio-imaging agent carriers, as well as antigen delivery vehicles. However, the impact of lipid composition on the performance of lipid-PLGA hybrid NPs as a delivery system has not been well investigated. In this study, the influence of lipid composition on the stability of the hybrid NPs and in vitro antigen release from NPs under different conditions was examined. The uptake of hybrid NPs with various surface charges by dendritic cells (DCs) was carefully studied. The results showed that PLGA NPs enveloped by a lipid shell with more positive surface charges could improve the stability of the hybrid NPs, enable better controlled release of antigens encapsulated in PLGA NPs, as well as enhance uptake of NPs by DC.

  17. Fabrication of PLGA/MWNTs composite electrospun fibrous scaffolds for improved myogenic differentiation of C2C12 cells.

    PubMed

    Xu, Jiazhu; Xie, Ya; Zhang, Hongbo; Ye, Zhaoyang; Zhang, Wenjun

    2014-11-01

    Electrically conducting scaffolds have attracted tremendous attention in skeletal muscle tissue engineering. In this paper, poly(lactic-co-glycolic acid) (PLGA)/multi-wall carbon nanotubes (MWNTs) composite fibrous scaffolds were fabricated using the electrospinning technique. The physical properties of the composite fibers were characterized and proliferation and differentiation of C2C12 cells on these scaffolds were examined. It was found that the addition of MWNTs modulated the physical properties of PLGA fibers including morphology, fiber diameter, degradation, tensile strength and electrical conductivity, depending on the amount of MWNTs. These fibrous scaffolds were cytocompatible and supported the proliferation of C2C12 cells. Importantly, C2C12 cells showed more mature myotube formation on PLGA/MWNTs composite fibrous scaffolds compared to PLGA scaffolds. These results indicate that PLGA/MWNTs composite electrospun fibers have great potential in skeletal muscle tissue engineering.

  18. Treating cutaneous squamous cell carcinoma using ALA PLGA nanoparticle-mediated photodynamic therapy in a mouse model

    NASA Astrophysics Data System (ADS)

    Wang, Xiaojie; Shi, Lei; Tu, Qingfeng; Wang, Hongwei; Zhang, Haiyan; Wang, Peiru; Zhang, Linglin; Huang, Zheng; Wang, Xiuli; Zhao, Feng; Luan, Hansen

    2015-03-01

    Background: Squamous cell carcinoma (SCC) is a common skin cancer and its treatment is still difficult. The aim of this study was to evaluate the effectiveness of nanoparticle (NP)-assisted ALA delivery for topical photodynamic therapy (PDT) of cutaneous SCC. Methods: UV-induced cutaneous SCCs were established in hairless mice. ALA loaded polylactic-co-glycolic acid (PLGA) NPs were prepared and characterized. The kinetics of ALA PLGA NPs-induced protoporphyrin IX (PpIX) fluorescence in SCCs, therapeutic efficacy of ALA NP-mediated PDT, and immune responses were examined. Results: PLGA NPs could enhance PpIX production in SCC. ALA PLGA NP mediated topical PDT was more effective than free ALA of the same concentration in treating cutaneous SCC. Conclusion: PLGA NPs provide a promising strategy for delivering ALA in topical PDT of cutaneous SCC.

  19. Gamma Irradiation of Active Self-healing PLGA Microspheres for Efficient Aqueous Encapsulation of Vaccine Antigens

    PubMed Central

    Desai, Kashappa-Goud H.; Kadous, Samer; Schwendeman, Steven P.

    2013-01-01

    Purpose To investigate the effect of γ-irradiation of poly(lactic-co-glycolic acid) (PLGA)/Al(OH)3/0 or 5 wt% diethyl phthalate (DEP) microspheres for active self-healing encapsulation of vaccine antigens. Methods Microspheres were irradiated with 60Co at 2.5 and 1.8 MRad and 0.37 and 0.20 MRad/h. Encapsulation of tetanus toxoid (TT) was achieved by mixing Al(OH)3-PLGA microspheres with TT solution at 10-38°C. Electron paramagnetic resonance (EPR) spectroscopy was used to examine free radical formation. Glass transition temperature (Tg) and molecular weight of PLGA was measured by differential scanning calorimetry and gel permeation chromatography, respectively. Loading and release of TT were examined by modified Bradford, amino acid analysis, and ELISA assays. Results EPR spectroscopy results indicated absence of free radicals in PLGA microspheres after γ-irradiation. Antigen-sorbing capacity, encapsulation efficiency, and Tg of the polymer were also not adversely affected. When DEP-loaded microspheres were irradiated at 0.2 MRad/h, some PLGA pores healed during irradiation and PLGA healing during encapsulation was suppressed. The molecular weight of PLGA was slightly reduced when DEP-loaded microspheres were irradiated at the same dose rate. These trends were not observed at 0.37 MRad/h. Gamma irradiation slightly increased TT initial burst release. Apart from the slightly higher polymer molecular weight decline caused by higher irradiation dose in case of DEP-loaded microspheres, the small increase in total irradiation dose from 1.8 to 2.5 MRad had insignificant effect on the polymer and microspheres properties analyzed. Conclusion Gamma irradiation is a plausible approach to provide a terminally sterilized, self-healing encapsulation PLGA excipient for vaccine delivery. PMID:23515830

  20. New synthesis and characterization of (+)-lysergic acid diethylamide (LSD) derivatives and the development of a microparticle-based immunoassay for the detection of LSD and its metabolites.

    PubMed

    Li, Z; Goc-Szkutnicka, K; McNally, A J; Pilcher, I; Polakowski, S; Vitone, S; Wu, R S; Salamone, S J

    1997-01-01

    In this paper are reported the synthesis and characterization of three LSD derivatives. On the basis of several analytical characterization studies, the most stable derivative has been selected and a procedure to covalently link the derivative to polystyrene microparticles through a carrier protein has been developed. In addition, two new LSD immunogens have been synthesized and characterized, and from these immunogens antibodies that recognize not only LSD but also several major LSD metabolites have been generated. Using the selected derivative and antibody, a homogeneous microparticle-based immunoassay has been developed for the detection of LSD in human urine with the required sensitivity and specificity for an effective screening assay. The performance of this LSD OnLine assay has been evaluated using the criteria of precision, cross-reactivity, correlation to the Abuscreen LSD RIA and GC/MS/MS, assay specificity, and limit of detection.

  1. Claudin 4-targeted protein incorporated into PLGA nanoparticles can mediate M cell targeted delivery

    PubMed Central

    Rajapaksa, Thejani E.; Stover-Hamer, Mary; Fernandez, Xiomara; Eckelhoefer, Holly A.; Lo, David D.

    2009-01-01

    Polymer-based microparticles are in clinical use mainly for their ability to provide controlled release of peptides and compounds, but they are also being explored for their potential to deliver vaccines and drugs as suspensions directly into mucosal sites. It is generally assumed that uptake is mediated by epithelial M cells, but this is often not directly measured. To study the potential for optimizing M cell uptake of polymer microparticles in vivo, we produced sub-micron size PLGA particles incorporating a recombinant protein. This recombinant protein was produced with or without a c-terminal peptide previously shown to have high affinity binding to Claudin 4, a protein associated with M cell endocytosis. While the PLGA nanoparticles incorporate the protein throughout the matrix, much of the protein was also displayed on the surface, allowing us to take advantage of the binding activity of the targeting peptide. Accordingly, we found that instillation of these nanoparticles into the nasal passages or stomach of mice was found to significantly enhance their uptake by upper airway and intestinal M cells. Our results suggest that a reasonably simple nanoparticle manufacture method can provide insight into developing an effective needle-free delivery system. PMID:19896996

  2. Current strategies in modification of PLGA-based gene delivery system.

    PubMed

    Ramezani, Mohammad; Ebrahimian, Mahboubeh; Hashemi, Maryam

    2016-12-05

    The successful gene therapy has been limited by safe and efficient delivery of nucleic acid to the target cells. Poly (d,l-lactide-co-glycolide) (PLGA) nanoparticles (NPs) are able to deliver drugs and gene efficiently. This formulation has several advantages in comparison with other formulations including improvement of solubility, stability, controlling of degradation and release of the entrapped agents. For application of PLGA as gene carrier, there exist many challenges. PLGA nanoparticles could protect the encapsulated DNA from in vivo degradation but the DNA release is slowl and their negative charge acts as a barrier to DNA incorporation and delivery. Also, during the preparation process, DNA could be exposed to high shear stress and organic solvents which could result in its inactivation. Moreover, PLGA NPs could be modified with different agents to reduce its cytotoxicity, to enhance the delivery efficiency and to target it to specific tissues/cells. This review summarizes different methods used for the preparation of PLGA NPs as gene carriers and recent strategies for modification of PLGA particles applied in gene therapy.

  3. pH-Responsive PLGA Nanoparticle for Controlled Payload Delivery of Diclofenac Sodium

    PubMed Central

    Khanal, Shalil; Adhikari, Udhab; Rijal, Nava P.; Bhattarai, Shanta R.; Sankar, Jagannathan; Bhattarai, Narayan

    2016-01-01

    Poly(lactic-co-glycolic acid) (PLGA) based nanoparticles have gained increasing attention in delivery applications due to their capability for controlled drug release characteristics, biocompatibility, and tunable mechanical, as well as degradation, properties. However, thorough study is always required while evaluating potential toxicity of the particles from dose dumping, inconsistent release and drug-polymer interactions. In this research, we developed PLGA nanoparticles modified by chitosan (CS), a cationic and pH responsive polysaccharide that bears repetitive amine groups in its backbone. We used a model drug, diclofenac sodium (DS), a nonsteroidal anti-inflammatory drug (NSAID), to study the drug loading and release characteristics. PLGA nanoparticles were synthesized by double-emulsion solvent evaporation technique. The nanoparticles were evaluated based on their particle size, surface charge, entrapment efficacy, and effect of pH in drug release profile. About 390–420 nm of average diameters and uniform morphology of the particles were confirmed by scanning electron microscope (SEM) imaging and dynamic light scattering (DLS) measurement. Chitosan coating over PLGA surface was confirmed by FTIR and DLS. Drug entrapment efficacy was up to 52%. Chitosan coated PLGA showed a pH responsive drug release in in vitro. The release was about 45% more at pH 5.5 than at pH 7.4. The results of our study indicated the development of chitosan coating over PLGA nanoparticle for pH dependent controlled release DS drug for therapeutic applications. PMID:27490577

  4. In vivo study of ALA PLGA nanoparticles-mediated PDT for treating cutaneous squamous cell carcinoma

    NASA Astrophysics Data System (ADS)

    Wang, Xiaojie; Shi, Lei; Huang, Zheng; Wang, Xiuli

    2014-09-01

    Background: Squamous cell carcinoma (SCC) is a common skin cancer and its treatment is still a challenge. Although topical photodynamic therapy (PDT) is effective for treating in situ and superficial SCC, the effectiveness of topical ALA delivery to thick SCC can be limited by its bioavailability. Polylactic-co-glycolic acid nanopartieles (PLGA NPs) might provide a promising ALA delivery strategy. The aim of this study was to evaluate the efficacy of ALA PLGA NPs PDT for the treatment of cutaneous SCC in a mouse model. Methods: ALA loaded PLGA NPs were prepared and characterized. The therapeutic efficacy of ALA PLGA NP mediated PDT in treating UV-induced cutaneous SCC in the mice model were examined. Results: In vivo study showed that ALA PLGA NPs PDT were more effective than free ALA of the same concentration in treating mouse cutaneous SCC. Conclusion: ALA PLGA NPs provides a promising strategy for delivering ALA and treating cutaneous SCC.

  5. Biomimetic Hybrid Nanofiber Sheets Composed of RGD Peptide-Decorated PLGA as Cell-Adhesive Substrates.

    PubMed

    Shin, Yong Cheol; Lee, Jong Ho; Kim, Min Jeong; Park, Ji Hoon; Kim, Sung Eun; Kim, Jin Su; Oh, Jin-Woo; Han, Dong-Wook

    2015-05-29

    In biomedical applications, there is a need for tissue engineering scaffolds to promote and control cellular behaviors, including adhesion, proliferation and differentiation. In particular, the initial adhesion of cells has a great influence on those cellular behaviors. In this study, we concentrate on developing cell-adhesive substrates applicable for tissue engineering scaffolds. The hybrid nanofiber sheets were prepared by electrospinning poly(lactic-co-glycolic acid) (PLGA) and M13 phage, which was genetically modified to enhance cell adhesion thru expressing RGD peptides on their surface. The RGD peptide is a specific motif of extracellular matrix (ECM) for integrin receptors of cells. RGD peptide-decorated PLGA (RGD-PLGA) nanofiber sheets were characterized by scanning electron microscopy, immunofluorescence staining, contact angle measurement and differential scanning calorimetry. In addition, the initial adhesion and proliferation of four different types of mammalian cells were determined in order to evaluate the potential of RGD-PLGA nanofiber sheets as cell-adhesive substrates. Our results showed that the hybrid nanofiber sheets have a three-dimensional porous structure comparable to the native ECM. Furthermore, the initial adhesion and proliferation of cells were significantly enhanced on RGD-PLGA sheets. These results suggest that biomimetic RGD-PLGA nanofiber sheets can be promising cell-adhesive substrates for application as tissue engineering scaffolds.

  6. Multifunctional Bi2S3/PLGA nanocapsule for combined HIFU/radiation therapy.

    PubMed

    Yao, Ming-hua; Ma, Ming; Chen, Yu; Jia, Xiao-qing; Xu, Guang; Xu, Hui-xiong; Chen, Hang-rong; Wu, Rong

    2014-09-01

    A multifunctional organic-inorganic hybrid nanocapsule based on Bi2S3-embedded poly (lactic-co-glycolic acid) (PLGA) nanocapsule has been elaborately designed to combine the merits of both polymeric shell structure and Bi2S3 nanoparticles. Hydrophobic Bi2S3 nanoparticles were successfully introduced into the PLGA nanocapsules via a facile and efficient water/oil/water (W/O/W) emulsion strategy. The elastic polymeric PLGA shell provides the excellent capability of ultrasound contrast imaging to the Bi2S3/PLGA. Meanwhile, the potential of these microcapsules to enhance the high intensity focused ultrasound (HIFU) therapy was demonstrated. Importantly, this research provided the first example of both in vitro and in vivo to demonstrate the radiosensitization effect of Bi2S3-embedded PLGA hybrid nanocapsules against prostate cancer under external X-ray irradiation. Thus, the successful integration of the Bi2S3 and PLGA nanocapsules provided an alternative strategy for the highly efficient ultrasound guided HIFU/RT synergistic therapy.

  7. BMP-2 Grafted nHA/PLGA Hybrid Nanofiber Scaffold Stimulates Osteoblastic Cells Growth

    PubMed Central

    Haider, Adnan; Kim, Sukyoung; Huh, Man-Woo; Kang, Inn-Kyu

    2015-01-01

    Biomaterials play a pivotal role in regenerative medicine, which aims to regenerate and replace lost/degenerated tissues or organs. Natural bone is a hierarchical structure, comprised of various cells having specific functions that are regulated by sophisticated mechanisms. However, the regulation of the normal functions in damaged or injured cells is disrupted. In order to address this problem, we attempted to artificially generate a scaffold for mimicking the characteristics of the extracellular matrix at the nanoscale level to trigger osteoblastic cell growth. For this purpose, we have chemically grafted bone morphogenetic protein (BMP-2) onto the surface of L-glutamic acid modified hydroxyapatite incorporated into the PLGA nanofiber matrix. After extensive characterization using various spectroscopic techniques, the BMP-g-nHA/PLGA hybrid nanofiber scaffolds were subjected to various in vitro cytocompatibility tests. The results indicated that BMP-2 on BMP-g-nHA/PLGA hybrid nanofiber scaffolds greatly stimulated osteoblastic cells growth, contrary to the nHA/PLGA and pristine PLGA nanofiber scaffold, which are used as control. These results suggest that BMP-g-nHA/PLGA hybrid nanofiber scaffold can be used as a nanodrug carrier for the controlled and targeted delivery of BMP-2, which will open new possibilities for enhancing bone tissue regeneration and will help in the treatment of various bone-related diseases in the future. PMID:26539477

  8. [Experimental research on the prevention of rabbit postoperative abdominal cavity adhesion with PLGA membrane].

    PubMed

    Pang, Xiubing; Pan, Yongming; Hua, Fei; Sun, Chaoying; Chen, Liang; Chen, Fangming; Zhu, Keyan; Xu, Jianqin; Chen, Minli

    2015-02-01

    The aim of this paper is to explore the prevention of rabbit postoperative abdominal cavity adhesion with poly (lactic-co-glycotic acid) (PLGA) membrane and the mechanism of this prevention function. Sixty-six Japanese white rabbits were randomly divided into normal control group, model control group and PLGA membrane group. The rabbits were treated with multifactor methods to establish the postoperative abdominal cavity adhesion models except for those in the normal control group. PLGA membrane was used to cover the wounds of rabbits in the PLGA membrane group and nothing covered the wounds of rabbits in the model control group. The hematologic parameters, liver and kidney functions and fibrinogen contents were detected at different time. The rabbit were sacrificed 1, 2, 4, 6, 12 weeks after the operations, respectively. The adhesions were graded blindly, and Masson staining and immunohistochemistry methods were used to observe the proliferation of collagen fiber and the expression of transforming growth factor β1 (TGF-β1) on the cecal tissues, respectively. The grade of abdominal cavity adhesion showed that the PLGA membrane-treated group was significant lower than that in the model control group, and it has no influence on liver and kidney function and hematologic parameters. But the fibrinogen content and the number of white blood cell in the PLGA membrane group were significant lower than those of model control group 1 week and 2 weeks after operation, respectively. The density of collagen fiber and optical density of TGF-β1 in the PLGA membrane group were significant lower than those of model control group. The results demonstrated that PLGA membrane could be effective in preventing the abdominal adhesions in rabbits, and it was mostly involved in the reducing of fibrinogen exudation, and inhibited the proliferation of collagen fiber and over-expression of TGF-β1.

  9. In-vitro anticancer and antimicrobial activities of PLGA/silver nanofiber composites prepared by electrospinning.

    PubMed

    Almajhdi, Fahad N; Fouad, H; Khalil, Khalil Abdelrazek; Awad, Hanem M; Mohamed, Sahar H S; Elsarnagawy, T; Albarrag, Ahmed M; Al-Jassir, Fawzi F; Abdo, Hany S

    2014-04-01

    In the present work, a series of 0, 1 and 7 wt% silver nano-particles (Ag NPs) incorporated poly lactic-co-glycolic acid (PLGA) nano-fibers were synthesized by the electrospinning process. The PLGA/Ag nano-fibers sheets were characterized using SEM, TEM and DSC analyses. The three synthesized PLGA/silver nano-fiber composites were screened for anticancer activity against liver cancer cell line using MTT and LDH assays. The anticancer activity of PLGA nano-fibers showed a remarkable improvement due to increasing the concentration of the Ag NPs. In addition to the given result, PLGA nano-fibers did not show any cytotoxic effect. However, PLGA nano-fibers that contain 1 % nano silver showed anticancer activity of 8.8 %, through increasing the concentration of the nano silver to 7 % onto PLGA nano-fibers, the anticancer activity was enhanced to a 67.6 %. Furthermore, the antibacterial activities of these three nano-fibers, against the five bacteria strains namely; E.coli o157:H7 ATCC 51659, Staphylococcus aureus ATCC 13565, Bacillus cereus EMCC 1080, Listeria monocytogenes EMCC 1875 and Salmonella typhimurium ATCC25566 using the disc diffusion method, were evaluated. Sample with an enhanced inhibitory effect was PLGA/Ag NPs (7 %) which inhibited all strains (inhibition zone diameter 10 mm); PLGA/Ag NPs (1 %) sample inhibited only one strain (B. cereus) with zone diameter 8 mm. The PLGA nano-fiber sample has not shown any antimicrobial activity. Based on the anticancer as well as the antimicrobial results in this study, it can be postulated that: PLGA nanofibers containing 7 % nano silver are suitable as anticancer- and antibiotic-drug delivery systems, as they will increase the anticancer as well as the antibiotic drug potency without cytotoxicity effect on the normal cells. These findings also suggest that Ag NPs, of the size (5-10 nm) evaluated in the present study, are appropriate for therapeutic application from a safety standpoint.

  10. Magnetic barcoded hydrogel microparticles for multiplexed detection.

    PubMed

    Bong, Ki Wan; Chapin, Stephen C; Doyle, Patrick S

    2010-06-01

    Magnetic polymer particles have been used in a wide variety of applications ranging from targeting and separation to diagnostics and imaging. Current synthesis methods have limited these particles to spherical or deformations of spherical morphologies. In this paper, we report the use of stop flow lithography to produce magnetic hydrogel microparticles with a graphical code region, a probe region, and a magnetic tail region. These anisotropic multifunctional magnetic polymer particles are an enhanced version of previously synthesized "barcoded" particles (Science, 2007, 315, 1393-1396) developed for the sensitive and rapid multiplexed sensing of nucleic acids. The newly added magnetic region has acquired dipole moments in the presence of weak homogeneous magnetic fields, allowing the particles to align along the applied field direction. The novel magnetic properties have led to practical applications in the efficient orientation and separation of the barcoded microparticles during biological assays without disrupting detection capabilities.

  11. In Vitro Evaluation of the Biological Responses of Canine Macrophages Challenged with PLGA Nanoparticles Containing Monophosphoryl Lipid A

    PubMed Central

    Guldner, Delphine; Hwang, Julianne K.; Cardieri, Maria Clara D.; Eren, Meaghan; Ziaei, Parissa; Norton, M. Grant; Souza, Cleverson D.

    2016-01-01

    Poly (lactic-co-glycolic acid) nanoparticles (PLGA NPs) have been considerably studied as a promising biodegradable delivery system to induce effective immune responses and to improve stability, safety, and cost effectiveness of vaccines. The study aimed at evaluating early inflammatory effects and cellular safety of PLGA NPs, co-encapsulating ovalbumin (PLGA/OVA NPs), as a model antigen and the adjuvant monophosphoryl lipid A (PLGA/MPLA NPs) as an adjuvant, on primary canine macrophages. The PLGA NPs constructs were prepared following the emulsion-solvent evaporation technique and further physic-chemically characterized. Peripheral blood mononuclear cells were isolated from canine whole blood by magnetic sorting and further cultured to generate macrophages. The uptake of PLGA NP constructs by macrophages was demonstrated by flow cytometry, transmission electron microscopy and confocal microscopy. Macrophage viability and morphology were evaluated by trypan blue exclusion and light microscopy. Macrophages were immunophenotyped for the expression of MHC-I and MHC-II and gene expression of Interleukin-10 (IL-10), Interleukin-12 (IL-12p40), and tumor necrosis factor alpha (TNF-α) were measured. The results showed that incubation of PLGA NP constructs with macrophages revealed effective early uptake of the PLGA NPs without altering the viability of macrophages. PLGA/OVA/MPLA NPs strongly induced TNF-α and IL-12p40 expression by macrophages as well as increase relative expression of MHC-I but not MHC-II molecules. Taken together, these results indicated that PLGA NPs with addition of MPLA represent a good model, when used as antigen carrier, for further, in vivo, work aiming to evaluate their potential to induce strong, specific, immune responses in dogs. PMID:27835636

  12. Micro/Nano Multilayered Scaffolds of PLGA and Collagen by Alternately Electrospinning for Bone Tissue Engineering

    NASA Astrophysics Data System (ADS)

    Kwak, Sanghwa; Haider, Adnan; Gupta, Kailash Chandra; Kim, Sukyoung; Kang, Inn-Kyu

    2016-07-01

    The dual extrusion electrospinning technique was used to fabricate multilayered 3D scaffolds by stacking microfibrous meshes of poly(lactic acid-co-glycolic acid) (PLGA) in alternate fashion to micro/nano mixed fibrous meshes of PLGA and collagen. To fabricate the multilayered scaffold, 35 wt% solution of PLGA in THF-DMF binary solvent (3:1) and 5 wt% solution of collagen in hexafluoroisopropanol (HFIP) with and without hydroxyapatite nanorods (nHA) were used. The dual and individual electrospinning of PLGA and collagen were carried out at flow rates of 1.0 and 0.5 mL/h, respectively, at an applied voltage of 20 kV. The density of collagen fibers in multilayered scaffolds has controlled the adhesion, proliferation, and osteogenic differentiation of MC3T3-E1 cells. The homogeneous dispersion of glutamic acid-modified hydroxyapatite nanorods (nHA-GA) in collagen solution has improved the osteogenic properties of fabricated multilayered scaffolds. The fabricated multilayered scaffolds were characterized using FT-IR, X-ray photoelectron spectroscopy, and transmission electron microscopy (TEM). The scanning electron microscopy (FE-SEM) was used to evaluate the adhesion and spreads of MC3T3-E1 cells on multilayered scaffolds. The activity of MC3T3-E1 cells on the multilayered scaffolds was evaluated by applying MTT, alkaline phosphatase, Alizarin Red, von Kossa, and cytoskeleton F-actin assaying protocols. The micro/nano fibrous PLGA-Col-HA scaffolds were found to be highly bioactive in comparison to pristine microfibrous PLGA and micro/nano mixed fibrous PLGA and Col scaffolds.

  13. Micro/Nano Multilayered Scaffolds of PLGA and Collagen by Alternately Electrospinning for Bone Tissue Engineering.

    PubMed

    Kwak, Sanghwa; Haider, Adnan; Gupta, Kailash Chandra; Kim, Sukyoung; Kang, Inn-Kyu

    2016-12-01

    The dual extrusion electrospinning technique was used to fabricate multilayered 3D scaffolds by stacking microfibrous meshes of poly(lactic acid-co-glycolic acid) (PLGA) in alternate fashion to micro/nano mixed fibrous meshes of PLGA and collagen. To fabricate the multilayered scaffold, 35 wt% solution of PLGA in THF-DMF binary solvent (3:1) and 5 wt% solution of collagen in hexafluoroisopropanol (HFIP) with and without hydroxyapatite nanorods (nHA) were used. The dual and individual electrospinning of PLGA and collagen were carried out at flow rates of 1.0 and 0.5 mL/h, respectively, at an applied voltage of 20 kV. The density of collagen fibers in multilayered scaffolds has controlled the adhesion, proliferation, and osteogenic differentiation of MC3T3-E1 cells. The homogeneous dispersion of glutamic acid-modified hydroxyapatite nanorods (nHA-GA) in collagen solution has improved the osteogenic properties of fabricated multilayered scaffolds. The fabricated multilayered scaffolds were characterized using FT-IR, X-ray photoelectron spectroscopy, and transmission electron microscopy (TEM). The scanning electron microscopy (FE-SEM) was used to evaluate the adhesion and spreads of MC3T3-E1 cells on multilayered scaffolds. The activity of MC3T3-E1 cells on the multilayered scaffolds was evaluated by applying MTT, alkaline phosphatase, Alizarin Red, von Kossa, and cytoskeleton F-actin assaying protocols. The micro/nano fibrous PLGA-Col-HA scaffolds were found to be highly bioactive in comparison to pristine microfibrous PLGA and micro/nano mixed fibrous PLGA and Col scaffolds.

  14. In vitro and in vivo effects of rat kidney vascular endothelial cells on osteogenesis of rat bone marrow mesenchymal stem cells growing on polylactide-glycoli acid (PLGA) scaffolds.

    PubMed

    Sun, Hongchen; Qu, Zhe; Guo, Ying; Zang, Guangxiang; Yang, Bai

    2007-11-04

    It is well established that vascularization is critical for osteogenesis. However, adequate vascularization also remains one of the major challenges in tissue engineering of bone. This problem is further accentuated in regeneration of large volume of tissue. Although a complex process, vascularization involves reciprocal regulation and functional interaction between endothelial and osteoblast-like cells during osteogenesis. This prompted us to investigate the possibility of producing bone tissue both in vitro and ectopically in vivo using vascular endothelial cells because we hypothesized that the direct contact or interaction between vascular endothelial cells and bone marrow mesenchymal stem cells are of benefit to osteogenesis in vitro and in vivo. For that purpose we co-cultured rat bone marrow mesenchymal stem cells (MSC) and kidney vascular endothelial cells (VEC) with polylactide-glycolic acid scaffolds. In vitro experiments using alkaline phosphatase and osteocalcin assays demonstrated the proliferation and differentiation of MSC into osteoblast-like cells, especially the direct contact between VEC and MSC. In addition, histochemical analysis with CD31 and von-Willebrand factor staining showed that VEC retained their endothelial characteristics. In vivo implantation of MSC and VEC co-cultures into rat's muscle resulted in pre-vascular network-like structure established by the VEC in the PLGA. These structures developed into vascularized tissue, and increased the amount and size of the new bone compared to the control group (p < 0.05). These results suggest that the vascular endothelial cells could efficiently stimulate the in vitro proliferation and differentiation of osteoblast-like cells and promote osteogenesis in vivo by the direct contact or interaction with the MSC. This technique for optimal regeneration of bone should be further investigated.

  15. In vitro drug release behavior, mechanism and antimicrobial activity of rifampicin loaded low molecular weight PLGA-PEG-PLGA triblock copolymeric nanospheres.

    PubMed

    Gajendiran, M; Divakar, S; Raaman, N; Balasubramanian, S

    2013-12-01

    Poly (lactic-co-glycolic acid) (PLGA (92:8)) and a series of PLGA-PEG-PLGA tri block copolymers were synthesized by direct melt polycondensation. The copolymers were characterized by FTIR, and 1HNMR spectroscopic techniques, viscosity, gel permeation chromatography (GPC) and powder x-ray diffraction (XRD). The rifampicin (RIF) loaded polymeric nanospheres (NPs) were prepared by ultrasonication-W/O emulsification technique. The NPs have been characterized by field emission scanning electron microscopy (FESEM), TEM, powder X-ray diffraction (XRD), UVvisible spectroscopy and DLS measurements. The drug loaded triblock copolymeric NPs have five folds higher drug content and drug loading efficiency than that of PLGA microspheres (MPs). The in vitro drug release study shows that the drug loaded NPs showed an initial burst release after that sustained release up to 72 h. All the triblock copolymeric NPs follow anomalous drug diffusion mechanism while the PLGA MPs follow non-Fickian super case-II mechanism up to 12 h. The overall in-vitro release follows second order polynomial kinetics up to 72 h. The antimicrobial activity of the RIF loaded polymer NPs was compared with that of pure RIF and tetracycline (TA). The RIF loaded triblock copolymeric NPs inhibited the bacterial growth more effectively than the pure RIF and TA.

  16. Fabrication of pseudo-ceramide-based lipid microparticles for recovery of skin barrier function.

    PubMed

    Kim, Do-Hoon; Park, Woo Ram; Kim, Jeong Hwan; Cho, Eun Chul; An, Eun Jung; Kim, Jin-Woong; Oh, Seong-Geun

    2012-06-01

    The recovery of skin barrier functions was investigated with pseudo-ceramide-based lipid microparticles. The microparticles were prepared by using a fluid bed technique where lipid components (a pseudo-ceramide, cholesterol and a fatty acid) were coated on a sugar seed, and a polymer was subsequently coated on the lipid microparticles. The microparticles contained large amount of pseudo-ceramide, and the pseudo-ceramide was in the form of lamellar structures mixed with other lipid components. In addition, the microparticles were stably dispersed in aqueous media or emulsion systems without any disruption of the microparticles' structures, thereby supplying sufficient amount of the pseudo-ceramide to skins for improving skin barrier functions such as preventing water loss. Such a role of the microparticles was proven by evaluating in vivo the efficacy of the lipid microparticles in reducing a trans-epidermal water loss (TEWL) of impaired murine skins. As a result, the novel pseudo-ceramide-based lipid microparticles for barrier recovery may potentially be applied in the field of dermatology, cosmetics and pharmaceuticals.

  17. HDL-Mimetic PLGA Nanoparticle To Target Atherosclerosis Plaque Macrophages

    PubMed Central

    Sanchez-Gaytan, Brenda L.; Fay, Francois; Lobatto, Mark E.; Tang, Jun; Ouimet, Mireille; Kim, YongTae; van der Staay, Susanne E. M.; van Rijs, Sarian M.; Priem, Bram; Zhang, Liangfang; Fisher, Edward A; Moore, Kathryn J.; Langer, Robert; Fayad, Zahi A.; Mulder, Willem J M

    2015-01-01

    High-density lipoprotein (HDL) is a natural nanoparticle that exhibits an intrinsic affinity for atherosclerotic plaque macrophages. Its natural targeting capability as well as the option to incorporate lipophilic payloads, e.g., imaging or therapeutic components, in both the hydrophobic core and the phospholipid corona make the HDL platform an attractive nanocarrier. To realize controlled release properties, we developed a hybrid polymer/HDL nanoparticle composed of a lipid/apolipoprotein coating that encapsulates a poly(lactic-co-glycolic acid) (PLGA) core. This novel HDL-like nanoparticle (PLGA–HDL) displayed natural HDL characteristics, including preferential uptake by macrophages and a good cholesterol efflux capacity, combined with a typical PLGA nanoparticle slow release profile. In vivo studies carried out with an ApoE knockout mouse model of atherosclerosis showed clear accumulation of PLGA–HDL nanoparticles in atherosclerotic plaques, which colocalized with plaque macrophages. This biomimetic platform integrates the targeting capacity of HDL biomimetic nanoparticles with the characteristic versatility of PLGA-based nanocarriers. PMID:25650634

  18. Heuristic modeling of macromolecule release from PLGA microspheres

    PubMed Central

    Szlęk, Jakub; Pacławski, Adam; Lau, Raymond; Jachowicz, Renata; Mendyk, Aleksander

    2013-01-01

    Dissolution of protein macromolecules from poly(lactic-co-glycolic acid) (PLGA) particles is a complex process and still not fully understood. As such, there are difficulties in obtaining a predictive model that could be of fundamental significance in design, development, and optimization for medical applications and toxicity evaluation of PLGA-based multiparticulate dosage form. In the present study, two models with comparable goodness of fit were proposed for the prediction of the macromolecule dissolution profile from PLGA micro- and nanoparticles. In both cases, heuristic techniques, such as artificial neural networks (ANNs), feature selection, and genetic programming were employed. Feature selection provided by fscaret package and sensitivity analysis performed by ANNs reduced the original input vector from a total of 300 input variables to 21, 17, 16, and eleven; to achieve a better insight into generalization error, two cut-off points for every method was proposed. The best ANNs model results were obtained by monotone multi-layer perceptron neural network (MON-MLP) networks with a root-mean-square error (RMSE) of 15.4, and the input vector consisted of eleven inputs. The complicated classical equation derived from a database consisting of 17 inputs was able to yield a better generalization error (RMSE) of 14.3. The equation was characterized by four parameters, thus feasible (applicable) to standard nonlinear regression techniques. Heuristic modeling led to the ANN model describing macromolecules release profiles from PLGA microspheres with good predictive efficiency. Moreover genetic programming technique resulted in classical equation with comparable predictability to the ANN model. PMID:24348037

  19. PLGA Nanoparticles as Subconjunctival Injection for Management of Glaucoma.

    PubMed

    Salama, Hamed A; Ghorab, Mahmoud; Mahmoud, Azza A; Abdel Hady, Mayssa

    2017-02-21

    Nanoparticles fabricated from the biodegradable and biocompatible polymer, polylactic-co-glycolic acid (PLGA), could be a promising system for targeting ocular drug delivery. The objective of this work was to investigate the possibility of encapsulating brinzolamide in PLGA nanoparticles in order to be applied as a subconjunctival injection that could represent a starting point for developing new therapeutic strategies against increase in ocular pressure. The brinzolamide-loaded PLGA nanoparticles were fabricated using emulsion-diffusion-evaporation method with varying concentrations of Tween 80 or poloxamer 188 (Plx) in aqueous and organic phases. The nanoparticles were characterized in terms of particle size and size distribution, entrapment efficiency and in-vitro drug release pattern as well as DSC and X-ray analysis. Nanoparticles prepared using Tween 80 in the aqueous phase showed higher encapsulation efficiency and smaller particle size-values compared to those prepared using Plx. Furthermore, the addition of Plx 188 or Brij 97 to the organic phase in the formulation containing Tween 80 in the aqueous phase led to an increase in the particle diameter-values of the obtained nanoparticles. The nanoparticles had the capacity to release the brinzolamide in a biphasic release profile. The nanoparticles were spherical in shape and the drug was entraped in the nanoparticles in an amorphous form. Selected nanoparticles, injected subconjunctivally in normotensive Albino rabbits, were able to reduce the IOP for up to 10 days. Nanoparticles loaded with brinzolamide with lower particle size were able to reduce the IOP for longer period compared to those with higher particle size. Histopathological studies for the anterior cross sections of the rabbits' eyes revealed that the tested nanoparticles were compatible with the ocular tissue. The overall results support that PLGA nanoparticles, applied as subconjunctival injection, can be considered as a promising carrier for

  20. PLGA-PEG-PLGA triblock copolymeric micelles as oral drug delivery system: In vitro drug release and in vivo pharmacokinetics assessment.

    PubMed

    Chen, Xiufen; Chen, Jianzhong; Li, Bowen; Yang, Xiang; Zeng, Rongjie; Liu, Yajun; Li, Tao; Ho, Rodney J Y; Shao, Jingwei

    2017-03-15

    Poly (d,l-lactide-co-glycolide)-poly (ethylene glycol)-poly (d,l-lactide-co-glycolide) triblock copolymers (PLGA-PEG-PLGA) has been proven to be desirable for anti-cancer drug delivery by intravenous administration. But till now there is no report of developing this micelle as a sustained oral formulation for cancer therapy. 3β-acetoxy-urs-12-en-28-oic acid hexamethylenediamine (US597), a derivative of natural product ursolic acid has been developed as a novel cancer metastasis chemopreventive agent by us. Herein, we developed a new oral dosage formulation of PLGA-PEG-PLGA tri-block micelles loaded with US597 (US597@micelles). US597@micelles was prepared by a double emulsion solvent evaporation method, and characterized in regards to mean diameter (<100nm), drug loading (25.9-28.5%), zeta potential (5.76-10.65mV) and encapsulation efficiency (55.7-74.3%), respectively. In vitro, US597@micelles could ameliorate sustained drug release, inhibit cell proliferation by inducing apoptosis (46.6% of late apoptosis), and influence the integrity of nuclei and mitochondrial on HepG2. Moreover, in vivo pharmacokinetic study by UPLC/MS/MS method demonstrated better absorption, metabolism and elimination characters of US597@micelles as an oral dosage form (Cmax=53±49ng/mL, t1/2=8.716±7.033h) over free US597 (Cmax=14±11ng/mL, t1/2=16.433±8.821h). In conclusion, PLGA-PEG-PLGA micelles as a promising oral drug delivery system are able to improve the bioavailability and efficacy of US597 in cancer therapy.

  1. An endothelial cultured condition medium embedded porous PLGA scaffold for the enhancement of mouse embryonic stem cell differentiation.

    PubMed

    Li, Ching-Wen; Pan, Wei-Ting; Ju, Jyh-Cherng; Wang, Gou-Jen

    2016-04-12

    In this study, we have developed a microporous poly(lactic-co-glycolic acid) (PLGA) scaffold that combines a continuous release property and a three-dimensional (3D) scaffolding technique for the precise and efficient formation of endothelial cell lineage from embryonic stem cells (ESCs). Eight PLGA scaffolds (14.29%, 16.67%, 20% and 25% concentrations of PLGA solutions) mixed with two crystal sizes of sodium chloride (NaCl) were fabricated by leaching. Then, vascular endothelial cell conditioned medium (ECCM) mixed with gelatin was embedded into the scaffold for culturing of mouse embryonic stem cells (mESCs). The 14.29% PLGA scaffolds fabricated using non-ground NaCl particles (NG-PLGA) and the 25% PLGA containing scaffolds fabricated using ground NaCl particles (G-PLGA) possessed minimum and maximum moisture content and bovine serum albumin (BSA) content properties, respectively. These two groups of scaffolds were used for future experiments in this study. Cell culture results demonstrated that the proposed porous scaffolds without growth factors were sufficient to induce mouse ESCs to differentiate into endothelial-like cells in the early culture stages, and combined with embedded ECCM could provide a long-term inducing system for ESC differentiation.

  2. Impact of PEG and PEG-b-PAGE modified PLGA on nanoparticle formation, protein loading and release.

    PubMed

    Rietscher, René; Czaplewska, Justyna A; Majdanski, Tobias C; Gottschaldt, Michael; Schubert, Ulrich S; Schneider, Marc; Lehr, Claus-Michael

    2016-03-16

    The effect of modifying the well-established pharmaceutical polymer PLGA by different PEG-containing block-copolymers on the preparation of ovalbumin (OVA) loaded PLGA nanoparticles (NPs) was studied. The used polymers contained poly(d,l-lactic-co-glycolic acid) (PLGA), polyethylene glycol (PEG) and poly(allyl glycidyl ether) (PAGE) as building blocks. The double emulsion technique yielded spherical NPs in the size range from 170 to 220 nm (PDI<0.15) for all the differently modified polymers, allowing to directly compare protein loading of and release. PEGylation is usually believed to increase the hydrophilic character of produced particles, favoring encapsulation of hydrophilic substances. However, in this study simple PEGylation of PLGA had only a slight effect on protein release. In contrast, incorporating a PAGE block between the PEG and PLGA units, also eventually enabling active targeting introducing a reactive group, led to a significantly higher loading (+25%) and release rate (+100%), compared to PLGA and PEG-b-PLGA NPs.

  3. PLGA based drug delivery systems: Promising carriers for wound healing activity.

    PubMed

    Chereddy, Kiran Kumar; Vandermeulen, Gaëlle; Préat, Véronique

    2016-03-01

    Wound treatment remains one of the most prevalent and economically burdensome healthcare issues in the world. Current treatment options are limited and require repeated administrations which led to the development of new therapeutics to satisfy the unmet clinical needs. Many potent wound healing agents were discovered but most of them are fragile and/or sensitive to in vivo conditions. Poly(lactic-co-glycolic acid) (PLGA) is a widely used biodegradable polymer approved by food and drug administration and European medicines agency as an excipient for parenteral administrations. It is a well-established drug delivery system in various medical applications. The aim of the current review is to elaborate the applications of PLGA based drug delivery systems carrying different wound healing agents and also present PLGA itself as a wound healing promoter. PLGA carriers encapsulating drugs such as antibiotics, anti-inflammatory drugs, proteins/peptides, and nucleic acids targeting various phases/signaling cycles of wound healing, are discussed with examples. The combined therapeutic effects of PLGA and a loaded drug on wound healing are also mentioned.

  4. Development of a porous PLGA-based scaffold for mastoid air cell regeneration

    PubMed Central

    Gould, Toby W. A.; Birchall, John P.; Mallick, Ali S.; Alliston, Tamara; Lustig, Lawrence R.; Shakesheff, Kevin M.

    2015-01-01

    Objective To develop a porous, biodegradable scaffold for mastoid air cell regeneration. Study Design In vitro development of a temperature-sensitive poly(DL-lactic acid-co-glycolic acid)/poly(ethylene glycol) (PLGA/PEG) scaffold tailored for this application. Methods Human mastoid bone microstructure and porosity was investigated using micro-computed tomography. PLGA/PEG-alginate scaffolds were developed and scaffold porosity was assessed. Human bone marrow mesenchymal stem cells (hBM-MSCs) were cultured on the scaffolds in vitro. Scaffolds were loaded with ciprofloxacin and release of ciprofloxacin over time in vitro was assessed. Results Porosity of human mastoid bone was measured at 83% with an average pore size of 1.3mm. PLGA/PEG-alginate scaffold porosity ranged from 43–78% depending on the alginate bead content. hBM-MSCs proliferate on the scaffolds in vitro, and release of ciprofloxacin from the scaffolds was demonstrated over 7–10 weeks. Conclusion The PLGA/PEG-alginate scaffolds developed in this study demonstrate similar structural features to human mastoid bone, support cell growth and display sustained antibiotic release. These scaffolds may be of potential clinical use in mastoid air cell regeneration. Further in vivo studies to assess the suitability of PLGA/PEG-alginate scaffolds for this application are required. PMID:23670365

  5. Persistence, distribution, and impact of distinctly segmented microparticles on cochlear health following in vivo infusion.

    PubMed

    Ross, Astin M; Rahmani, Sahar; Prieskorn, Diane M; Dishman, Acacia F; Miller, Josef M; Lahann, Joerg; Altschuler, Richard A

    2016-06-01

    Delivery of pharmaceuticals to the cochleae of patients with auditory dysfunction could potentially have many benefits from enhancing auditory nerve survival to protecting remaining sensory cells and their neuronal connections. Treatment would require platforms to enable drug delivery directly to the cochlea and increase the potential efficacy of intervention. Cochlear implant recipients are a specific patient subset that could benefit from local drug delivery as more candidates have residual hearing; and since residual hearing directly contributes to post-implantation hearing outcomes, it requires protection from implant insertion-induced trauma. This study assessed the feasibility of utilizing microparticles for drug delivery into cochlear fluids, testing persistence, distribution, biocompatibility, and drug release characteristics. To allow for delivery of multiple therapeutics, particles were composed of two distinct compartments; one containing polylactide-co-glycolide (PLGA), and one composed of acetal-modified dextran and PLGA. Following in vivo infusion, image analysis revealed microparticle persistence in the cochlea for at least 7 days post-infusion, primarily in the first and second turns. The majority of subjects maintained or had only slight elevation in auditory brainstem response thresholds at 7 days post-infusion compared to pre-infusion baselines. There was only minor to limited loss of cochlear hair cells and negligible immune response based on CD45+ immunolabling. When Piribedil-loaded microparticles were infused, Piribedil was detectable within the cochlear fluids at 7 days post-infusion. These results indicate that segmented microparticles are relatively inert, can persist, release their contents, and be functionally and biologically compatible with cochlear function and therefore are promising vehicles for cochlear drug delivery. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 1510-1522, 2016.

  6. Knockdown of STAT3 expression in SKOV3 cells by biodegradable siRNA-PLGA/CSO conjugate micelles.

    PubMed

    Zhao, Yunchun; Zheng, Caihong; Zhang, Li; Chen, Yue; Ye, Yiqing; Zhao, Mengdan

    2015-03-01

    Biodegradable and biocompatible poly(d,l-lactic-co-glycolic acid) (PLGA)was conjugated to the 5'-thiol end of signal transducer and activator of transcription 3 (STAT3) small interfering RNA (STAT3-siRNA) via a disulfide bond. In aqueous environments, these siRNA-PLGA conjugates can spontaneously form core/shell type spherical micelles with a particle size of about 200 nm. A biodegradable, low molecular weight cationic polymer, chitosan oligosaccharide (CSO), was added to the siRNA-PLGA micelles at different nitrogen to phosphate (N/P) ratios to form stable, spherical siRNA-PLGA/CSO micelles with sizes of 150-180 nm. The siRNA-PLGA/CSO micelles were produced via ionic complexation between negatively charged siRNA and positively charged CSO on the outer shell of the micelles. The siRNA-PLGA/CSO micelles exhibited superior cellular uptake and STAT3 gene silencing efficiency in SKOV3 ovarian cancer cells when compared with siRNA/CSO complexes at the same N/P ratios with no significant differences with lipofectamine 2000. Furthermore, the siRNA-PLGA/CSO micelles showed that the efficiencies of cellular uptake and STAT3 gene silencing gradually increased with increasing N/P ratios. The siRNA-PLGA/CSO micelles also inhibited the growth of SKOV3 cells, as well as, promoted apoptosis of the cells. These results indicate that siRNA-PLGA/CSO micelles can be utilized as a novel and efficient siRNA carrier to treat a variety of diseases.

  7. TPGS2k/PLGA nanoparticles for overcoming multidrug resistance by interfering mitochondria of human alveolar adenocarcinoma cells.

    PubMed

    Wang, Dong-Fang; Rong, Wen-Ting; Lu, Yu; Hou, Jie; Qi, Shan-Shan; Xiao, Qing; Zhang, Jue; You, Jin; Yu, Shu-Qin; Xu, Qian

    2015-02-25

    In this study, we successfully synthesized d-α-tocopheryl polyethylene glycol 2000 succinate (TPGS2k) and prepared TPGS2k-modified poly(lactic-co-glycolic acid) nanoparticles (TPGS2k/PLGA NPs) loaded with 7-ethyl-10-hydroxycamptothecin (SN-38), designated TPGS2k/PLGA/SN-38 NPs. Characterization measurements showed that TPGS2k/PLGA/SN-38 NPs displayed flat and spheroidal particles with diameters of 80-104 nm. SN-38 was encapsulated in TPGS2k emulsified PLGA NPs with the entrapment efficiency and loading rates of SN-38 83.6 and 7.85%, respectively. SN-38 could release constantly from TPGS2k/PLGA/SN-38 NPs in vitro. TPGS2k/PLGA/SN-38 NPs induced significantly higher cytotoxicity on A549 cells and the multidrug resistance (MDR) cell line (A549/DDP cells and A549/Taxol cells) compared with free SN-38. Further studies on the mechanism of the NPs in increasing the death of MDR cells showed that following the SN-38 releasing into cytoplasm the remaining TPGS2k/PLGA NPs could reverse the P-gp mediated MDR via interfering with the structure and function of mitochondria and rather than directly inhibiting the enzymatic activity of P-gp ATPase. Therefore, TPGS2k/PLGA NPs can reduce the generation of ATP and the release of energy for the requisite of P-gp efflux transporters. The results indicated that TPGS2k/PLGA NPs could become the nanopharmaceutical materials with the capability to reversal MDR and improve anticancer effects of some chemotherapy drugs as P-gp substrates.

  8. A Microparticle/Hydrogel Combination Drug-Delivery System for Sustained Release of Retinoids

    PubMed Central

    Gao, Song-Qi; Maeda, Tadao; Okano, Kiichiro; Palczewski, Krzysztof

    2012-01-01

    Purpose. To design and develop a drug-delivery system containing a combination of poly(d,l-lactide-co-glycolide) (PLGA) microparticles and alginate hydrogel for sustained release of retinoids to treat retinal blinding diseases that result from an inadequate supply of retinol and generation of 11-cis-retinal. Methods. To study drug release in vivo, either the drug-loaded microparticle–hydrogel combination was injected subcutaneously or drug-loaded microparticles were injected intravitreally into Lrat−/− mice. Orally administered 9-cis-retinoids were used for comparison and drug concentrations in plasma were determined by HPLC. Electroretinography (ERG) and both chemical and histologic analyses were used to evaluate drug effects on visual function and morphology. Results. Lrat−/− mice demonstrated sustained drug release from the microparticle/hydrogel combination that lasted 4 weeks after subcutaneous injection. Drug concentrations in plasma of the control group treated with the same oral dose rose to higher levels for 6−7 hours but then dropped markedly by 24 hours. Significantly increased ERG responses and a markedly improved retinal pigmented epithelium (RPE)–rod outer segment (ROS) interface were observed after subcutaneous injection of the drug-loaded delivery combination. Intravitreal injection of just 2% of the systemic dose of drug-loaded microparticles provided comparable therapeutic efficacy. Conclusions. Sustained release of therapeutic levels of 9-cis-retinoids was achieved in Lrat−/− mice by subcutaneous injection in a microparticle/hydrogel drug-delivery system. Both subcutaneous and intravitreal injections of drug-loaded microparticles into Lrat−/− mice improved visual function and retinal structure. PMID:22918645

  9. Neutrophil-derived microparticles induce myeloperoxidase-mediated damage of vascular endothelial cells

    PubMed Central

    2014-01-01

    Background Upon activation neutrophil releases microparticles - small plasma membrane vesicles that contain cell surface proteins and cytoplasmic matter, with biological activities. In this study we investigated the potential role of myeloperoxidase in the endothelial cell injury caused by neutrophil-derived microparticles. Results Microparticles were produced by activating human neutrophils with a calcium ionophore and characterized by flow cytometry and transmission and scanning electron microscopy. Myeloperoxidase activity was measured by luminol-dependent chemiluminescence. Neutrophil microparticles-induced injuries and morphological alterations in human umbilical vein endothelial cells (HUVECs) were evaluated by microscopy and flow cytometry. Neutrophil microparticles were characterized as structures bounded by lipid bilayers and were less than 1 μm in diameter. The microparticles also expressed CD66b, CD62L and myeloperoxidase, which are all commonly expressed on the surface of neutrophils, as well as exposition of phosphatidylserine. The activity of the myeloperoxidase present on the microparticles was confirmed by hypochlorous acid detection. This compound is only catalyzed by myeloperoxidase in the presence of hydrogen peroxide and chloride ion. The addition of sodium azide or taurine inhibited and reduced enzymatic activity, respectively. Exposure of HUVEC to neutrophil microparticles induced a loss of cell membrane integrity and morphological changes. The addition of sodium azide or myeloperoxidase-specific inhibitor-I consistently reduced the injury to the endothelial cells. Taurine addition reduced HUVEC morphological changes. Conclusions We have demonstrated the presence of active myeloperoxidase in neutrophil microparticles and that the microparticle-associated myeloperoxidase cause injury to endothelial cells. Hence, the microparticle-associated myeloperoxidase-hydrogen peroxide-chloride system may contribute to widespread endothelial cell damage

  10. Suppression of atopic dermatitis in mice model by reducing inflammation utilizing phosphatidylserine-coated biodegradable microparticles.

    PubMed

    Kumar, Purnima; Hosain, Md Zahangir; Kang, Jeong-Hun; Takeo, Masafumi; Kishimura, Akihiro; Mori, Takeshi; Katayama, Yoshiki

    2015-01-01

    Controlling inflammatory response is important to avoid chronic inflammation in many diseases including atopic dermatitis (AD). In this research, we tried using a phosphatidylserine (PS)-coated microparticles in the AD mouse model for achieving the modulation of the macrophage phenotype to an anti-inflammatory state. Here, we prepared poly (D,L-lactic acid) microparticle coated with PS on the outside shell. We confirmed the cellular uptake of the PS-coated microparticle, which leads to the significant downregulation of the inflammatory cytokine production. In the mouse model of AD, the PS-coated microparticle was injected subcutaneously for a period of 12 days. The mice showed significant reduction in the development of AD symptoms comparing with the mice treated with the PC-coated microparticle.

  11. Microencapsulation of a synbiotic into PLGA/alginate multiparticulate gels.

    PubMed

    Cook, Michael T; Tzortzis, George; Charalampopoulos, Dimitris; Khutoryanskiy, Vitaliy V

    2014-05-15

    Probiotic bacteria have gained popularity as a defence against disorders of the bowel. However, the acid sensitivity of these cells results in a loss of viability during gastric passage and, consequently, a loss of efficacy. Probiotic treatment can be supplemented using 'prebiotics', which are carbohydrates fermented specifically by probiotic cells in the body. This combination of probiotic and prebiotic is termed a 'synbiotic'. Within this article a multiparticulate dosage form has been developed, consisting of poly(d,l-lactic-co-glycolic acid) (PLGA) microcapsules containing prebiotic Bimuno™ incorporated into an alginate-chitosan matrix containing probiotic Bifidobacterium breve. The aim of this multiparticulate was that, in vivo, the probiotic would be protected against gastric acid and the release of the prebiotic would occur in the distal colon. After microscopic investigation, this synbiotic multiparticulate was shown to control the release of the prebiotic during in vitro gastrointestinal transit, with the release of galacto-oligosaccharides (GOS) initially occurred over 6h, but with a triphasic release pattern giving further release over 288 h. Encapsulation of B. breve in multiparticulates resulted in a survival of 8.0 ± 0.3 logCFU/mL cells in acid, an improvement over alginate-chitosan microencapsulation of 1.4 logCFU/mL. This was attributed to increased hydrophobicity by the incorporation of PLGA particles.

  12. Apatite coating of electrospun PLGA fibers using a PVA vehicle system carrying calcium ions.

    PubMed

    Kim, In Ae; Rhee, Sang-Hoon

    2010-01-01

    A novel method to coat electrospun poly(D,L-lactic-co-glycolic acid) (PLGA) fiber surfaces evenly and efficiently with low-crystalline carbonate apatite crystals using a poly(vinyl alcohol) (PVA) vehicle system carrying calcium ions was presented. A non-woven PLGA fabric was prepared by electrospinning: a 10 wt% PLGA solution was prepared using 1,1,3,3-hexafluoro-2-propanol as a solvent and electrospun under a electrical field of 1 kV/cm using a syringe pump with a flowing rate of 3 ml/h. The non-woven PLGA fabric, 12 mm in diameter and 1 mm in thickness, was cut and then coated with a PVA solution containing calcium chloride dihydrate (specimen PPC). As controls, pure non-woven PLGA fabric (specimen P) and fabric coated with a calcium chloride dihydrate solution without PVA (specimen PC) were also prepared. Three specimens were exposed to simulated body fluid for 1 week and this exposure led to form uniform and complete apatite coating layer on the fiber surfaces of specimen PPC. However, no apatite had formed to the fiber surfaces of specimen P and only inhomogeneous coating occurred on the fiber surfaces of specimen PC. These results were explained in terms of the calcium chelating and adhesive properties of PVA vehicle system. The practical implication of the results is that this method provides a simple but efficient technique for coating the fiber surface of an initially non-bioactive material with low-crystalline carbonate apatite.

  13. Ozone Gas as a Benign Sterilization Treatment for PLGA Nanofiber Scaffolds

    PubMed Central

    de Jesus Andreoli Pinto, Terezinha; Bou-Chacra, Nadia Araci; Galante, Raquel; de Araújo, Gabriel Lima Barros; do Nascimento Pedrosa, Tatiana; Maria-Engler, Silvya Stuchi

    2016-01-01

    The use of electrospun nanofibers for tissue engineering and regenerative medicine applications is a growing trend as they provide improved support for cell proliferation and survival due, in part, to their morphology mimicking that of the extracellular matrix. Sterilization is a critical step in the fabrication process of implantable biomaterial scaffolds for clinical use, but many of the existing methods used to date can negatively affect scaffold properties and performance. Poly(lactic-co-glycolic acid) (PLGA) has been widely used as a biodegradable polymer for 3D scaffolds and can be significantly affected by current sterilization techniques. The aim of this study was to investigate pulsed ozone gas as an alternative method for sterilizing PLGA nanofibers. The morphology, mechanical properties, physicochemical properties, and response of cells to PLGA nanofiber scaffolds were assessed following different degrees of ozone gas sterilization. This treatment killed Geobacillus stearothermophilus spores, the most common biological indicator used for validation of sterilization processes. In addition, the method preserved all of the characteristics of nonsterilized PLGA nanofibers at all degrees of sterilization tested. These findings suggest that ozone gas can be applied as an alternative method for sterilizing electrospun PLGA nanofiber scaffolds without detrimental effects. PMID:26757850

  14. In vitro hemocompatibility and cytocompatibility of dexamethasone-eluting PLGA stent coatings

    NASA Astrophysics Data System (ADS)

    Zhang, Jiang; Liu, Yang; Luo, Rifang; Chen, Si; Li, Xin; Yuan, Shuheng; Wang, Jin; Huang, Nan

    2015-02-01

    Drug-eluting stents (DESs) have been an important breakthrough for interventional cardiology applications since 2002. Though successful in reducing restenosis, some adverse clinical problems still emerged, which were mostly caused by the bare-metal stents and non-biodegradable polymer coatings, associated with the delayed endothelialization process. In this study, dexamethasone-loaded poly (lactic-co-glycolic acid) (PLGA) coatings were developed to explore the potential application of dexamethasone-eluting stents. Dexamethasone-eluting PLGA stents were prepared using ultrasonic atomization spray method. For other tests like stability and cytocompatibility and hemocompatibility tests, dexamethasone loaded coatings were deposited on 316L SS wafers. Fourier transform-infrared spectroscopy (FT-IR) results demonstrated that there was no chemical reaction between PLGA and dexamethasone. The balloon expansion experiment and surface morphology observation suggested that the stent coatings were smooth and uniform, and could also withstand the compressive and tensile strains imparted without cracking after stent expansion. The drug release behavior in vitro indicated that dexamethasone existed burst release within 1 day, but it presented linear release characteristics after 6 days. In vitro platelets adhesion, activation test and APTT test were also done, which showed that after blending dexamethasone into PLGA, the hemocompatibility was improved. Besides, dexamethasone and dexamethasone-loaded PLGA coatings could significantly inhibit the attachment and proliferation of smooth muscle cells.

  15. In vitro characterization of hepatocyte growth factor release from PHBV/PLGA microsphere scaffold.

    PubMed

    Zhu, Xin Hao; Wang, Chi-Hwa; Tong, Yen Wah

    2009-05-01

    Polymer scaffolds which can support cells to grow as well as deliver growth factors to the cells simultaneously have great potential for the successful regeneration of failed tissues. As popularly used vehicles to deliver anti-cancer drugs and growth factors, microspheres also show many advantages as substrates to guide the growth of cells. Therefore, we aimed to examine the feasibility of using microspheres as ideal scaffolds for liver tissue engineering. To determine the capabilities of previously used microsphere scaffold to deliver growth factors simultaneously, this work investigated a long-term (about three months) release of bovine serum albumin (BSA) from microsphere scaffolds fabricated by using two different polymers, poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV, 8% PHV), poly(lactide-co-glycolide) acid (PLGA, 5050) and a blend of PLGA and PHBV. BSA served as a model for hepatocyte growth factor (HGF) since both proteins have similar molecular weights and hydrophilicity. Furthermore, HGF was encapsulated into the PLGA/PHBV composite microsphere with a core-shell structure, and sustained delivery of HGF with maintained bioactivity was achieved for at least 40 days. The moderate degradation rate (about 55% loss of the initial mass) and well-preserved structure after three months of incubation indicated that the PLGA/PHBV composite microspheres would therefore be more suitable than the pure PHBV or PLGA microspheres as a scaffold for engineering liver tissue.

  16. PHBV microspheres--PLGA matrix composite scaffold for bone tissue engineering.

    PubMed

    Huang, Wei; Shi, Xuetao; Ren, Li; Du, Chang; Wang, Yingjun

    2010-05-01

    Polymer scaffolds, particularly in the form of microspheres, have been employed to support cells growth and deliver drugs or growth factors in tissue engineering. In this study, we have established a scaffold by embedding poly (beta-hydroxybutyrate-co-beta-hydroxyvalerate) (PHBV) microspheres into poly (L-lactic-co-glycolic acid) (PLGA) matrix, according to their different solubility in acetone, with the aim of repairing bone defects. PLGA/PHBV scaffolds had good pore parameters, for example, the porosity of PLGA/30% PHBV scaffold can reach to 81.273 +/- 2.192%. Besides, the pore size distribution of the model was evaluated and the results revealed that the pore size mainly distributed between 50 mum and 200 mum. With increasing the amount of PHBV microspheres, the compressive strength of the PLGA/PHBV scaffold enhanced. The morphology of the hybrid scaffold was rougher than that of pure PLGA scaffold, which had no significant effect on the cell behavior. The in vitro evaluation suggested that the model is suitable as a scaffold for engineering bone tissue, and has the potential for further applications in drug delivery system.

  17. Biodegradable effect of PLGA membrane in alveolar bone regeneration on beagle dog.

    PubMed

    Hua, Nan; Ti, Vivian Lao; Xu, Yuanzhi

    2014-11-01

    Guided bone regeneration (GBR) is a principle adopted from guided tissue regeneration (GTR). Wherein, GBR is used for the healing of peri-implant bony dehiscences, for the immediate placement of implants into extraction sockets and for the augmentation of atrophic alveolar ridges. This procedure is done by the placement of a resorbable or non-resorbable membrane that will exclude undesirable types of tissue growth between the extraction socket and the soft tissue to allow only bone cells to regenerate in the surgically treated lesion. Here, we investigated the biodegradable effect of polylactic-co-glycolic acid (PLGA) membrane in the alveolar bone on Beagle dogs. Results show that both collagen and PLGA membrane had been fully resorbed, biodegraded, at four weeks post-operative reentry into the alveolar bone. Histological results under light microscopy revealed formation of new bone trabeculae in the extraction sites on both collagen and PLGA membrane. In conclusion, PLGA membrane could be a potential biomaterials for use on GBR and GTR. Nevertheless, further studies will be necessary to elucidate the efficiency and cost effectiveness of PLGA as GBR membrane in clinical.

  18. Ozone Gas as a Benign Sterilization Treatment for PLGA Nanofiber Scaffolds.

    PubMed

    Rediguieri, Carolina Fracalossi; Pinto, Terezinha de Jesus Andreoli; Bou-Chacra, Nadia Araci; Galante, Raquel; de Araújo, Gabriel Lima Barros; Pedrosa, Tatiana do Nascimento; Maria-Engler, Silvya Stuchi; De Bank, Paul A

    2016-04-01

    The use of electrospun nanofibers for tissue engineering and regenerative medicine applications is a growing trend as they provide improved support for cell proliferation and survival due, in part, to their morphology mimicking that of the extracellular matrix. Sterilization is a critical step in the fabrication process of implantable biomaterial scaffolds for clinical use, but many of the existing methods used to date can negatively affect scaffold properties and performance. Poly(lactic-co-glycolic acid) (PLGA) has been widely used as a biodegradable polymer for 3D scaffolds and can be significantly affected by current sterilization techniques. The aim of this study was to investigate pulsed ozone gas as an alternative method for sterilizing PLGA nanofibers. The morphology, mechanical properties, physicochemical properties, and response of cells to PLGA nanofiber scaffolds were assessed following different degrees of ozone gas sterilization. This treatment killed Geobacillus stearothermophilus spores, the most common biological indicator used for validation of sterilization processes. In addition, the method preserved all of the characteristics of nonsterilized PLGA nanofibers at all degrees of sterilization tested. These findings suggest that ozone gas can be applied as an alternative method for sterilizing electrospun PLGA nanofiber scaffolds without detrimental effects.

  19. Anticancer Activity of Nanoparticles Based on PLGA and its Co-polymer: In-vitro Evaluation

    PubMed Central

    Amjadi, Issa; Rabiee, Mohammad; Hosseini, Motahare-Sadat

    2013-01-01

    Attempts have been made to prepare nanoparticles based on poly(lactic-co-glycolic acid) (PLGA) and doxorubicin. Biological evaluation and physio-chemical characterizations were performed to elucidate the effects of initial drug loading and polymer composition on nanoparticle properties and its antitumor activity. PLGA nanoparticles were formulated by sonication method. Lactide/glycolide ratio and doxorubicin amounts have been tailored. Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC) were employed to identify the presence of doxorubicin within nanospheres. The in vitro release studies were performed to determine the initial ant net release rates over 24 h and 20 days, respectively. Furthermore, cytotoxicity assay was measured to evaluate therapeutic potency of doxorubicin-loaded nanoparticles. Spectroscopy and thermal results showed that doxorubicin was loaded into the particles successfully. It was observed that lactide/glycolide content of PLGA nanoparticles containing doxorubicin has more prominent role in tuning particle characteristics. Doxorubicin release profiles from PLGA 75 nanospheres demonstrated that the cumulative release rate increased slightly and higher initial burst was detected in comparison to PLGA 50 nanoparticles. MTT data revealed doxorubicin induced antitumor activity was enhanced by encapsulation process, and increasing drug loading and glycolide portion. The results led to the conclusion that by controlling the drug loading and the polymer hydrophilicity, we can adjust the drug targeting and blood clearance, which may play a more prominent role for application in chemotherapy. PMID:24523742

  20. Porous nano-hydroxyapatite/collagen scaffold containing drug-loaded ADM-PLGA microspheres for bone cancer treatment.

    PubMed

    Rong, Zi-Jie; Yang, Lian-Jun; Cai, Bao-Ta; Zhu, Li-Xin; Cao, Yan-Lin; Wu, Guo-Feng; Zhang, Zan-Jie

    2016-05-01

    To develop adriamycin (ADM)-encapsulated poly(lactic-co-glycolic acid) (PLGA) nanoparticles in a porous nano-hydroxyapatite/collagen scaffold (ADM-PLGA-NHAC). To provide novel strategies for future treatment of osteosarcoma, the properties of the scaffold, including its in vitro extended-release properties, the inhibition effects of ADM-PLGA-NHAC on the osteosarcoma MG63 cells, and its bone repair capacity, were investigated in vivo and in vitro. The PLGA copolymer was utilized as a drug carrier to deliver ADM-PLGA nanoparticles (ADM-PLGA-NP). Porous nano-hydroxyapatite and collagen were used to materials to produce the porous nano-hydroxyapatite/collagen scaffold (NHAC), into which the ADM-PLGA-NP was loaded. The performance of the drug-carrying scaffold was assessed using multiple techniques, including scanning electron microscopy and in vitro extended release. The antineoplastic activities of scaffold extracts on the human osteosarcoma MG63 cell line were evaluated in vitro using the cell counting kit-8 (CCK8) method and live-dead cell staining. The bone repair ability of the scaffold was assessed based on the establishment of a femoral condyle defect model in rabbits. ADM-PLGA-NHAC and NHAC were implanted into the rat muscle bag for immune response experiments. A tumor-bearing nude mice model was created, and the TUNEL and HE staining results were observed under optical microscopy to evaluate the antineoplastic activity and toxic side effects of the scaffold. The composite scaffold demonstrated extraordinary extended-release properties, and its extracts also exhibited significant inhibition of the growth of osteosarcoma MG63 cells. In the bone repair experiment, no significant difference was observed between ADM-PLGA-NHAC and NHAC by itself. In the immune response experiments, ADM-PLGA-NHAC exhibited remarkable biocompatibility. The in vivo antitumor experiment revealed that the implantation of ADM-PLGA-NHAC in the tumor resulted in a improved antineoplastic

  1. Evaluation of an orthotopically implanted calcium phosphate cement containing gelatin microparticles.

    PubMed

    Link, Dennis P; van den Dolder, Juliette; van den Beucken, Jeroen J J P; Habraken, Wouter; Soede, Annemieke; Boerman, Otto C; Mikos, Antonios G; Jansen, John A

    2009-08-01

    This study focused on the degradation properties of gelatin microparticles incorporated in calcium phosphate (CaP) cement and the subsequent effect of these composites on bone formation. Positively charged alkaline gelatin (type A) microparticles or negatively charged acidic gelatin (type B) microparticles were incorporated in CaP cement, which was implanted in critical-sized cranial defect in rats and left in place for 2, 4, and 8 weeks. The degradation of the gelatin was monitored using radioiodinated microparticles. After 4 and 8 weeks of implantation, a significantly faster degradation of type A gelatin over type B gelatin was found. Light microscopic analysis of the specimens showed similar bone response concerning implants containing either type A or B gelatin microparticles. At 2 weeks of implantation, a minimal amount of bone formation was observed from the cranial bone toward the implant, while after 8 weeks of implantation an entire layer of newly formed bone was present from the cranial bone toward the implant periphery. Bone ingrowth into the implant was observed at sites of gelatin microparticle degradation, predominantly at the implant periphery. Histomorphometrical evaluation did not reveal significant differences in bone formation between CaP cement incorporated with either type A or B gelatin microparticles during implantation periods up to 8 weeks. In conclusion, this study demonstrates that gelatin type influences the degradation of gelatin microparticles incorporated in CaP cements. However, this difference in degradation and the concomitant subsequent macroporosity did not induce differences in the biological response.

  2. Effect of Formulation and Process Parameters on Chitosan Microparticles Prepared by an Emulsion Crosslinking Technique.

    PubMed

    Rodriguez, Lidia B; Avalos, Abraham; Chiaia, Nicholas; Nadarajah, Arunan

    2016-12-19

    There are many studies about the synthesis of chitosan microparticles; however, most of them have very low production rate, have wide size distribution, are difficult to reproduce, and use harsh crosslinking agents. Uniform microparticles are necessary to obtain repeatable drug release behavior. The main focus of this investigation was to study the effect of the process and formulation parameters during the preparation of chitosan microparticles in order to produce particles with narrow size distribution. The technique evaluated during this study was emulsion crosslinking technique. Chitosan is a biocompatible and biodegradable material but lacks good mechanical properties; for that reason, chitosan was ionically crosslinked with sodium tripolyphosphate (TPP) at three different ratios (32, 64, and 100%). The model drug used was acetylsalicylic acid (ASA). During the preparation of the microparticles, chitosan was first mixed with ASA and then dispersed in oil containing an emulsifier. The evaporation of the solvents hardened the hydrophilic droplets forming microparticles with spherical shape. The process and formulation parameters were varied, and the microparticles were characterized by their morphology, particle size, drug loading efficiency, and drug release behavior. The higher drug loading efficiency was achieved by using 32% mass ratio of TPP to chitosan. The average microparticle size was 18.7 μm. The optimum formulation conditions to prepare uniform spherical microparticles were determined and represented by a region in a triangular phase diagram. The drug release analyses were evaluated in phosphate buffer solution at pH 7.4 and were mainly completed at 24 h.

  3. PLGA particulate delivery systems for subunit vaccines: Linking particle properties to immunogenicity.

    PubMed

    Silva, A L; Soema, P C; Slütter, B; Ossendorp, F; Jiskoot, W

    2016-04-02

    Among the emerging subunit vaccines are recombinant protein- and synthetic peptide-based vaccine formulations. However, proteins and peptides have a low intrinsic immunogenicity. A common strategy to overcome this is to co-deliver (an) antigen(s) with (an) immune modulator(s) by co-encapsulating them in a particulate delivery system, such as poly(lactic-co-glycolic acid) (PLGA) particles. Particulate PLGA formulations offer many advantages for antigen delivery as they are biocompatible and biodegradable; can protect the antigens from degradation and clearance; allow for co-encapsulation of antigens and immune modulators; can be targeted to antigen presenting cells; and their particulate nature can increase uptake and cross-presentation by mimicking the size and shape of an invading pathogen. In this review we discuss the pros and cons of using PLGA particulate formulations for subunit vaccine delivery and provide an overview of formulation parameters that influence their adjuvanticity and the ensuing immune response.

  4. PLGA particulate delivery systems for subunit vaccines: Linking particle properties to immunogenicity

    PubMed Central

    Silva, A. L.; Soema, P. C.; Slütter, B.; Ossendorp, F.; Jiskoot, W.

    2016-01-01

    ABSTRACT Among the emerging subunit vaccines are recombinant protein- and synthetic peptide-based vaccine formulations. However, proteins and peptides have a low intrinsic immunogenicity. A common strategy to overcome this is to co-deliver (an) antigen(s) with (an) immune modulator(s) by co-encapsulating them in a particulate delivery system, such as poly(lactic-co-glycolic acid) (PLGA) particles. Particulate PLGA formulations offer many advantages for antigen delivery as they are biocompatible and biodegradable; can protect the antigens from degradation and clearance; allow for co-encapsulation of antigens and immune modulators; can be targeted to antigen presenting cells; and their particulate nature can increase uptake and cross-presentation by mimicking the size and shape of an invading pathogen. In this review we discuss the pros and cons of using PLGA particulate formulations for subunit vaccine delivery and provide an overview of formulation parameters that influence their adjuvanticity and the ensuing immune response. PMID:26752261

  5. Effects of Microemulsion Preparation Conditions on Drug Encapsulation Efficiency of PLGA Nanoparticles

    NASA Astrophysics Data System (ADS)

    Ng, Set Hui; Ooi, Ing Hong

    2011-12-01

    Emulsion solvent evaporation technique is widely used to prepare nanoparticles of many organic polymer drug carriers. The mechanism of nanoparticle generation by this technique involves oil-in-water (O/W) microemulsion formation followed by solvent evaporation. Various microemulsion preparation conditions can affect the encapsulation efficiency of drug in the nanoparticulate carrier. In this study, emulsifying speed, emulsifying temperature, and organic-to-aqueous phase ratio were varied and the resulting encapsulation efficiency of a model drug in Poly(Lactide-co-Glycolide) (PLGA) nanoparticles was determined. The organic phase containing PLGA and a model drug dissolved in chloroform was first dispersed in an aqueous solution containing 0.5 %(w/v) Poly(vinyl alcohol) (PVA), which was then homogenized at high speeds. The resulting O/W microemulsion was subsequently subjected to stirring at room temperature for four hours during which the solvent diffused and evaporated gradually. The fine white suspension was centrifuged and freeze-dried. The model drug loading in the PLGA nanoparticles was determined using UV spectrophotometry. Results showed that the encapsulation efficiency of a model drug, salicylic acid, ranged from 8.5% to 17% depending on the microemulsion preparation conditions. Under the same temperature (15 °C) and homogenization speed (19000 rpm) conditions studied, a relatively high organic-to-aqueous phase ratio (1:5) provided salicylic acid loaded PLGA nanoparticles with significantly higher drug encapsulation efficiency. In addition, under all microemulsion preparation conditions, PLGA nanoparticles obtained after solvent evaporation and freeze drying were spherical and aggregation between the nanoparticles was not observed under a high power microscope. This indicates that PLGA nanoparticles with desirable amount of drug and with anticipated size and shape can be realized by controlling emulsification process conditions.

  6. Lactosylated PLGA nanoparticles containing ϵ-polylysine for the sustained release and liver-targeted delivery of the negatively charged proteins.

    PubMed

    Zhou, Ping; An, Tong; Zhao, Chuan; Li, Yuan; Li, Rongshan; Yang, Rui; Wang, Yinsong; Gao, Xiujun

    2015-01-30

    The acidic internal pH environment, initial burst release and lack of targeting property are main limitations of poly(lactide-co-glycolide) (PLGA) nanoparticles for carrying proteins. In this study, ϵ-polylysine (ϵ-PL) was used as an anti-acidic agent and a protein protectant to prepare PLGA nanoparticles for the protein delivery. To obtain the liver-targeting capability, lactosylated PLGA (Lac-PLGA) was synthesized by conjugation of lactose acid to PLGA at both ends, and then used to prepare nanoparticles containing ϵ-PL by the nanoprecipitation method. Bovine serumal bumin (BSA), a negatively charged protein, was efficiently loaded into Lac-PLGA/ϵ-PL nanoparticles and exhibited significant decreased burst release in vitro, sustained release in the blood and increased liver distribution in mice after intravenous injections. The enhanced stability of BSA was due to its electrical interaction with ϵ-PL and the neutralized internal environment of nanoparticles. In conclusion, Lac-PLGA/ϵ-PL nanoparticle system can be used as a promising carrier for the negatively charged proteins.

  7. Nano and microparticle engineering of water insoluble drugs using a novel spray-drying process.

    PubMed

    Schafroth, Nina; Arpagaus, Cordin; Jadhav, Umesh Y; Makne, Sushil; Douroumis, Dennis

    2012-02-01

    In the current study nano and microparticle engineering of water insoluble drugs was conducted using a novel piezoelectric spray-drying approach. Cyclosporin A (CyA) and dexamethasone (DEX) were encapsulated in biodegradable poly(D,L-lactide-co-glycolide) (PLGA) grades of different molecular weights. Spray-drying studies carried out with the Nano Spray Dryer B-90 employed with piezoelectric driven actuator. The processing parameters including inlet temperature, spray mesh diameter, sample flow rate, spray rate, applied pressure and sample concentration were examined in order to optimize the particle size and the obtained yield. The process parameters and the solute concentration showed a profound effect on the particle engineering and the obtained product yield. The produced powder presented consistent and reproducible spherical particles with narrow particle size distribution. Cyclosporin was found to be molecularly dispersed while dexamethasone was in crystalline state within the PLGA nanoparticles. Further evaluation revealed excellent drug loading, encapsulation efficiency and production yield. In vitro studies demonstrated sustained release patterns for the active substances. This novel spray-drying process proved to be efficient for nano and microparticle engineering of water insoluble active substances.

  8. Bone-Healing Capacity of PCL/PLGA/Duck Beak Scaffold in Critical Bone Defects in a Rabbit Model

    PubMed Central

    Lee, Jae Yeon; Son, Soo Jin; Son, Jun Sik; Kang, Seong Soo; Choi, Seok Hwa

    2016-01-01

    Bone defects are repaired using either natural or synthetic bone grafts. Poly(ϵ-caprolactone) (PCL), β-tricalcium phosphate (TCP), and poly(lactic-co-glycolic acid) (PLGA) are widely used as synthetic materials for tissue engineering. This study aimed to investigate the bone-healing capacity of PCL/PLGA/duck beak scaffold in critical bone defects and the oxidative stress status of the graft site in a rabbit model. The in vivo performance of 48 healthy New Zealand White rabbits, weighing between 2.5 and 3.5 kg, was evaluated. The rabbits were assigned to the following groups: group 1 (control), group 2 (PCL/PLGA hybrid scaffolds), group 3 (PCL/PLGA/TCP hybrid scaffolds), and group 4 (PCL/PLGA/DB hybrid scaffolds). A 5 mm critical defect was induced in the diaphysis of the left radius. X-ray, micro-CT, and histological analyses were conducted at (time 0) 4, 8, and 12 weeks after implantation. Furthermore, bone formation markers (bone-specific alkaline phosphatase, carboxyterminal propeptide of type I procollagen, and osteocalcin) were measured and oxidative stress status was determined. X-ray, micro-CT, biochemistry, and histological analyses revealed that the PCL/PLGA/duck beak scaffold promotes new bone formation in rabbit radius by inducing repair, suggesting that it could be a good option for the treatment of fracture. PMID:27042660

  9. pH-dependent antibacterial effects on oral microorganisms through pure PLGA implants and composites with nanosized bioactive glass.

    PubMed

    Hild, Nora; Tawakoli, Pune N; Halter, Jonas G; Sauer, Bärbel; Buchalla, Wolfgang; Stark, Wendelin J; Mohn, Dirk

    2013-11-01

    Biomaterials made of biodegradable poly(α-hydroxyesters) such as poly(lactide-co-glycolide) (PLGA) are known to decrease the pH in the vicinity of the implants. Bioactive glass (BG) is being investigated as a counteracting agent buffering the acidic degradation products. However, in dentistry the question arises whether an antibacterial effect is rather obtained from pure PLGA or from BG/PLGA composites, as BG has been proved to be antimicrobial. In the present study the antimicrobial properties of electrospun PLGA and BG45S5/PLGA fibres were investigated using human oral bacteria (specified with mass spectrometry) incubated for up to 24 h. BG45S5 nanoparticles were prepared by flame spray synthesis. The change in colony-forming units (CFU) of the bacteria was correlated with the pH of the medium during incubation. The morphology and structure of the scaffolds as well as the appearance of the bacteria were followed bymicroscopy. Additionally, we studied if the presence of BG45S5 had an influence on the degradation speed of the polymer. Finally, it turned out that the pH increase induced by the presence of BG45S5 in the scaffold did not last long enough to show a reduction in CFU. On the contrary, pure PLGA demonstrated antibacterial properties that should be taken into consideration when designing biomaterials for dental applications.

  10. Transferrin surface-modified PLGA nanoparticles-mediated delivery of a proteasome inhibitor to human pancreatic cancer cells.

    PubMed

    Frasco, Manuela F; Almeida, Gabriela M; Santos-Silva, Filipe; Pereira, Maria do Carmo; Coelho, Manuel A N

    2015-04-01

    The aim of this study was to develop a drug delivery system based on poly(lactic-co-glycolic acid) (PLGA) nanoparticles for an efficient and targeted action of the proteasome inhibitor bortezomib against pancreatic cancer cells. The PLGA nanoparticles were formulated with a poloxamer, and further surface-modified with transferrin for tumor targeting. The nanoparticles were characterized as polymer carriers of bortezomib, and the cellular uptake and growth inhibitory effects were evaluated in pancreatic cells. Cellular internalization of nanoparticles was observed in normal and cancer cells, but with higher uptake by cancer cells. The sustained release of the loaded bortezomib from PLGA nanoparticles showed cytotoxic effects against pancreatic normal and cancer cells. Noteworthy differential cytotoxicity was attained by transferrin surface-modified PLGA nanoparticles since significant cell growth inhibition by delivered bortezomib was only observed in cancer cells. These findings demonstrate that the ligand transferrin enhanced the targeted delivery of bortezomib-loaded PLGA nanoparticles to pancreatic cancer cells. These in vitro results highlight the transferrin surface-modified PLGA nanoparticles as a promising system for targeted delivery of anticancer drugs.

  11. Neoangiogenesis of human mesenchymal stem cells transfected with peptide-loaded and gene-coated PLGA nanoparticles.

    PubMed

    Park, Ji Sun; Yang, Han Na; Yi, Se Won; Kim, Jae-Hwan; Park, Keun-Hong

    2016-01-01

    Several factors are involved in angiogenesis. To form new blood vessels, we fabricated vehicles carrying an angiogenesis-related peptide (apelin) and gene (vascular endothelial growth factor (VEGF)165) that were internalized by human mesenchymal stem cells (hMSCs). These non-toxic poly-(DL)-lactic-co-glycolic acid (PLGA) nanoparticles (NPs) easily entered hMSCs without cytotoxicity. The negatively charged outer surface of PLGA NPs can be easily complexed with highly positively charged polyethylenimine (PEI) to deliver genes into cells. PLGA NPs complexed with PEI could be coated with negatively charged VEGF plasmid DNA and loaded with apelin. The physical characteristics of these PLGA NPs were determined by size distribution, gel retardation, and morphological analyses. Transfection of VEGF-coated apelin-loaded PLGA NPs resulted in the differentiation of hMSCs into endothelial cells and vascular formation in Matrigel in vitro. Following injection of hMSCs transfected with these PLGA NPs into an ischemic hind limb mouse model, these cells differentiated into endothelial cells and accelerated neovascularization.

  12. The Influence of Side Group Modification in Polyphosphazenes on Hydrolysis and Cell Adhesion of Blends with PLGA

    PubMed Central

    Krogman, Nicholas R.; Weikel, Arlin L.; Kristhart, Katherine A.; Nukavaropu, Syam P.; Deng, Meng; Nair, Lakshmi S.; Laurencin, Cato T.; Allcock, Harry R.

    2009-01-01

    Polyphosphazenes have been synthesized with tris(hydroxymethyl)amino methane (THAM) side groups and with co-substituents glycine ethyl ester and alanine ethyl ester. The THAM side group was linked to the polyphosphazene backbone via the amino function. The three pendent hydroxyl functions on each THAM side group were utilized for hydrogen bonding association with poly(glycolic-lactic acid) (PLGA). Co-substitution of the polyphosphazene with both THAM and glycine or alanine ethyl esters was employed to avoid the insolubility of the single-substituent THAM -substituted polyphosphazenes. Both poly[(tris(hydroxymethyl)aminomethane)(ethyl glycinato)phosphazene] and poly[(tris(hydroxymethyl)aminomethane)(ethyl alanato)phosphazene] (1:1 ratio of side groups) were blended with PLGA (50:50) or PLGA (85:15). DSC analysis indicated miscible blend formation, irrespective of the detailed molecular structure of the polyphosphazene or the composition of PLGA in the blend. Hydrolysis studies of the polyphosphazene:PLGA (50:50) blends indicated that the PLGA component hydrolyzed more rapidly than the polyphosphazene. Primary osteoblast cell studies showed good cell adhesion to the polymer blends during 14 days, but subsequent limited cell spreading due to increased surface roughness as the two polymers eroded at different rates. PMID:19345410

  13. Fabrication and in vivo evaluation of Nelfinavir loaded PLGA nanoparticles for enhancing oral bioavailability and therapeutic effect

    PubMed Central

    Venkatesh, D. Nagasamy; Baskaran, Mahendran; Karri, Veera Venkata Satyanarayana Reddy; Mannemala, Sai Sandeep; Radhakrishna, Kollipara; Goti, Sandip

    2015-01-01

    Nelfinavir mesylate (NFV) is an anti-viral drug, used in the treatment of Acquired Immunodeficiency Syndrome (AIDS). Poor oral bioavailability and shorter half-life (3.5–5 h) remain a major clinical limitation of NFV leading to unpredictable drug bioavailability and frequent dosing. In this context, the objective of the present study was to formulate NFV loaded poly (lactic-co-glycolic acid) (PLGA) nanoparticles (NPs), which can increase the solubility and oral bioavailability along with sustained release of the drug. NFV loaded PLGA-NPs were prepared by nanoprecipitation method using PLGA and Poloxomer 407. The prepared NPs were evaluated for particle size, zeta potential, morphology, drug content, entrapment efficiency (EE) and in vitro dissolution studies. Oral bioavailability studies were carried out in New Zealand rabbits by administering developed NFV PLGA-NPs and pure drug suspension. PLGA-NPs prepared by using 1:4 ratio of drug and PLGA, with a stirring rate of 1500 rpm for 4 h. The prepared NPs were in the size of 185 ± 0.83 nm with a zeta potential of 28.7 ± 0.09 mV. The developed NPs were found to be spherical with uniform size distribution. The drug content and EE of the optimized formulation were found to be 36 ± 0.19% and 72 ± 0.47% respectively. After oral administration of NFV PLGA-NPs, the relative bioavailability was enhanced about 4.94 fold compared to NFV suspension as a control. The results describe an effective strategy for oral delivery of NFV loaded PLGA NPs that helps in enhancing bioavailability and reduce the frequency of dosing. PMID:26702262

  14. Cationic nanoparticles with quaternary ammonium-functionalized PLGA-PEG-based copolymers for potent gene transfection

    NASA Astrophysics Data System (ADS)

    Wang, Yan-Hsung; Fu, Yin-Chih; Chiu, Hui-Chi; Wang, Chau-Zen; Lo, Shao-Ping; Ho, Mei-Ling; Liu, Po-Len; Wang, Chih-Kuang

    2013-11-01

    The objective of the present work was to develop new cationic nanoparticles (cNPs) with amphiphilic cationic copolymers for the delivery of plasmid DNA (pDNA). Cationic copolymers were built on the synthesis of quaternary ammonium salt compounds from diethylenetriamine (DETA) to include the positively charged head group and amphiphilic multi-grafts. PLGA- phe-PEG- qDETA (PPD), phe-PEG- qDETA-PLGA (PDP), and PLGA- phe-PEG- qDETA-PLGA (PPDP) cationic copolymers were created by this moiety of DETA quaternary ammonium, heterobifunctional polyethylene glycol (COOH-PEG-NH2), phenylalanine ( phe), and poly(lactic- co-glycolic acid) (PLGA). These new cNPs were prepared by the water miscible solvent displacement method. They exhibit good pDNA binding ability, as shown in a retardation assay that occurred at a particle size of 217 nm. The zeta potential was approximately +21 mV when the cNP concentration was 25 mg/ml. The new cNPs also have a better buffering capacity than PLGA NPs. However, the pDNA binding ability was demonstrated starting at a weight ratio of approximately 6.25 cNPs/pDNA. Gene transfection results showed that these cNPs had transfection effects similar to those of Lipofectamine 2000 in 293T cells. Furthermore, cNPs can also transfect human adipose-derived stem cells. The results indicate that the newly developed cNP is a promising candidate for a novel gene delivery vehicle.

  15. Biodegradable PLGA- b-PEG polymeric nanoparticles: synthesis, properties, and nanomedical applications as drug delivery system

    NASA Astrophysics Data System (ADS)

    Locatelli, Erica; Comes Franchini, Mauro

    2012-12-01

    During the past decades many synthetic polymers have been studied for nanomedicine applications and in particular as drug delivery systems. For this purpose, polymers must be non-toxic, biodegradable, and biocompatible. Polylactic- co-glycolic acid (PLGA) is one of the most studied polymers due to its complete biodegradability and ability to self-assemble into nanometric micelles that are able to entrap small molecules like drugs and to release them into body in a time-dependent manner. Despite fine qualities, using PLGA polymeric nanoparticles for in vivo applications still remains an open challenge due to many factors such as poor stability in water, big diameter (150-200 nm), and the removal of these nanocarriers from the blood stream by the liver and spleen thus reducing the concentration of drugs drastically in tumor tissue. Polyethylene glycol (PEG) is the most used polymers for drug delivery applications and the first PEGylated product is already on the market for over 20 years. This is due to its stealth behavior that inhibits the fast recognition by the immune system (opsonization) and generally leads to a reduced blood clearance of nanocarriers increasing blood circulation time. Furthermore, PEG is hydrophilic and able to stabilize nanoparticles by steric and not ionic effects especially in water. PLGA-PEG block copolymer is an emergent system because it can be easily synthesized and it possesses all good qualities of PLGA and also PEG capability so in the last decade it arose as one of the most promising systems for nanoparticles formation, drug loading, and in vivo drug delivery applications. This review will discuss briefly on PLGA- b-PEG synthesis and physicochemical properties, together with its improved qualities with respect to the single PLGA and PEG polymers. Moreover, we will focus on but in particular will treat nanoparticles formation and uses as new drug delivery system for nanomedical applications.

  16. A comparative study of gelatin sponge scaffolds and PLGA scaffolds transplanted to completely transected spinal cord of rat.

    PubMed

    Du, Bao-ling; Zeng, Chen-guang; Zhang, Wei; Quan, Da-ping; Ling, Eng-ang; Zeng, Yuan-shan

    2014-06-01

    This study sought to investigate whether gelatin sponge (GS) scaffold would produce less acidic medium in injured spinal cord, as compared with poly(lactic-co-glycolic acid) (PLGA) scaffold, to determine which of the two scaffolds as the biomaterial is more suitable for transplantation into spinal cord. GS scaffold or PLGA scaffold was transplanted into a transected spinal cord in this study. Two months after transplantation of scaffolds, acid sensing ion channel 1a (ASIC1a) positive cells expressing microtubule associated protein 2 (Map2) were observed as well as expressing adenomatous polyposis coli (APC) in spinal cord. GFAP positive cells were distributed at the rostral and caudal of the injury/graft area in the GS and PLGA groups. Western blot showed ASIC1a and GFAP expression of injured spinal cord was downregulated in the GS group. The number of CD68 positive cells was fewer and NF nerve fibers were more in the GS group. Nissl staining and cell counting showed that the number of survival neurons was comparable between the GS and PLGA groups in the pyramidal layer of sensorimotor cortex and the red nucleus of midbrain. However, in the Clarke's nucleus at L1 spinal segment, the surviving neurons in the GS group were more numerous than that in the PLGA group. H&E staining showed that the tissue cavities in the GS group were smaller in size than that in the PLGA group. The results suggest that GS scaffold is more suitable for transplantation to promote the recovery of spinal cord injury compared with PLGA scaffold.

  17. Critical rolling angle of microparticles

    NASA Astrophysics Data System (ADS)

    Farzi, Bahman; Vallabh, Chaitanya K. P.; Stephens, James D.; Cetinkaya, Cetin

    2016-03-01

    At the micrometer-scale and below, particle adhesion becomes particularly relevant as van der Waals force often dominates volume and surface proportional forces. The rolling resistance of microparticles and their critical rolling angles prior to the initiation of free-rolling and/or complete detachment are critical in numerous industrial processes and natural phenomenon involving particle adhesion and granular dynamics. The current work describes a non-contact measurement approach for determining the critical rolling angle of a single microparticle under the influence of a contact-point base-excitation generated by a transient displacement field of a prescribed surface acoustic wave pulse and reports the critical rolling angle data for a set of polystyrene latex microparticles.

  18. Sophoridine-loaded PLGA microspheres for lung targeting: preparation, in vitro, and in vivo evaluation.

    PubMed

    Wang, Wenping; Cai, Yaqin; Zhang, Guangxing; Liu, Yanhua; Sui, Hong; Park, Kinam; Wang, Hong

    2016-11-01

    Lung-targeting sophoridine-loaded poly(lactide-co-glycolide) (PLGA) microspheres were constructed by a simple oil-in-oil emulsion-solvent evaporation method. The obtained microspheres were systematically studied on their morphology, size distribution, drug loading, encapsulation efficiency, in vitro release profile, and biodistribution in rats. The drug-loaded microparticles showed as tiny spheres under SEM and had an average size of 17 μm with 90% of the microspheres ranging from 12 to 24 μm. The drug loading and encapsulation efficiency were 65% and 6.5%, respectively. The in vitro drug release behavior of microspheres exhibited an initial burst of 16.6% at 4 h and a sustained-release period of 14 days. Drug concentration in lung tissue of rats was 220.10 μg/g for microspheres and 6.77 μg/g for solution after intraveneous injection for 30 min, respectively. And the microsphere formulation showed a significantly higher drug level in lung tissue than in other major organs and blood samples for 12 days. These results demonstrated that the obtained PLGA microspheres could potentially improve the treatment efficacy of sophoridine against lung cancer.

  19. Functionalised alginate flow seeding microparticles for use in Particle Image Velocimetry (PIV).

    PubMed

    Varela, Sylvana; Balagué, Isaac; Sancho, Irene; Ertürk, Nihal; Ferrando, Montserrat; Vernet, Anton

    2016-01-01

    Alginate microparticles as flow seeding fulfil all the requirements that are recommended for the velocity measurements in Particle Image Velocimetry (PIV). These spherical microparticles offer the advantage of being environmentally friendly, having excellent seeding properties and they can be produced via a very simple process. In the present study, the performances of alginate microparticles functionalised with a fluorescent dye, Rhodamine B (RhB), for PIV have been studied. The efficacy of fluorescence is appreciated in a number of PIV applications since it can boost the signal-to-noise ratio. Alginate microparticles functionalised with RhB have high emission efficiency, desirable match with fluid density and controlled size. The study of the particles behaviour in strong acid and basic solutions and ammonia is also included. This type of particles can be used for measurements with PIV and Planar Laser Induced Fluorescence (PLIF) simultaneously, including acid-base reactions.

  20. Electrospun PDLLA/PLGA composite membranes for potential application in guided tissue regeneration.

    PubMed

    Zhang, Ershuai; Zhu, Chuanshun; Yang, Jun; Sun, Hong; Zhang, Xiaomin; Li, Suhua; Wang, Yonglan; Sun, Lu; Yao, Fanglian

    2016-01-01

    With the aim to explore a membrane system with appropriate degradation rate and excellent cell-occlusiveness for guided tissue regeneration (GTR), a series of poly(D, L-lactic acid) (PDLLA)/poly(D, L-lactic-co-glycolic acid) (PLGA) (100/0, 70/30, 50/50, 30/70, 0/100, w/w) composite membranes were fabricated via electrospinning. The fabricated membranes were evaluated by morphological characterization, water contact angle measurement and tensile test. In vitro degradation was characterized in terms of the weight loss and the morphological change. Moreover, in vitro cytologic research revealed that PDLLA/PLGA composite membranes could efficiently inhibit the infiltration of 293 T cells. Finally, subcutaneous implant test on SD rat in vivo showed that PDLLA/PLGA (70/30, 50/50) composite membranes could function well as a physical barrier to prevent cellular infiltration within 13 weeks. These results suggested that electrospun PDLLA/PLGA (50/50) composite membranes could serve as a promising barrier membrane for guided tissue regeneration due to suitable biodegradability, preferable mechanical properties and excellent cellular shielding effects.

  1. Peptide/protein vaccine delivery system based on PLGA particles

    PubMed Central

    Allahyari, Mojgan; Mohit, Elham

    2016-01-01

    abstract Due to the excellent safety profile of poly (D,L-lactide-co-glycolide) (PLGA) particles in human, and their biodegradability, many studies have focused on the application of PLGA particles as a controlled-release vaccine delivery system. Antigenic proteins/peptides can be encapsulated into or adsorbed to the surface of PLGA particles. The gradual release of loaded antigens from PLGA particles is necessary for the induction of efficient immunity. Various factors can influence protein release rates from PLGA particles, which can be defined intrinsic features of the polymer, particle characteristics as well as protein and environmental related factors. The use of PLGA particles encapsulating antigens of different diseases such as hepatitis B, tuberculosis, chlamydia, malaria, leishmania, toxoplasma and allergy antigens will be described herein. The co-delivery of antigens and immunostimulants (IS) with PLGA particles can prevent the systemic adverse effects of immunopotentiators and activate both dendritic cells (DCs) and natural killer (NKs) cells, consequently enhancing the therapeutic efficacy of antigen-loaded PLGA particles. We will review co-delivery of different TLR ligands with antigens in various models, highlighting the specific strengths and weaknesses of the system. Strategies to enhance the immunotherapeutic effect of DC-based vaccine using PLGA particles can be designed to target DCs by functionalized PLGA particle encapsulating siRNAs of suppressive gene, and disease specific antigens. Finally, specific examples of cellular targeting where decorating the surface of PLGA particles target orally administrated vaccine to M-cells will be highlighted. PMID:26513024

  2. Pharmacokinetics and distributions of bevacizumab by intravitreal injection of bevacizumab-PLGA microspheres in rabbits

    PubMed Central

    Ye, Zhuo; Ji, Yan-Li; Ma, Xiang; Wen, Jian-Guo; Wei, Wei; Huang, Shu-Man

    2015-01-01

    AIM To investigate the pharmacokinetics and distributions of bevacizumab by intravitreal injection of prepared bevacizumab-poly (L-lactic-co-glycolic acid) (PLGA) microspheres in rabbits, to provide evidence for clinical application of this kind of bevacizumab sustained release dosage form. METHODS Bevacizumab was encapsulated into PLGA microsphere via the solid-in-oil-in-hydrophilic oil (S/O/hO) method. Fifteen healthy New Zealand albino-rabbits were used in experiments. The eyes of each rabbit received an intravitreal injection. The left eyes were injected with prepared bevacizumab-PLGA microspheres and the right eyes were injected with bevacizumab solution. After intravitreal injection, rabbits were randomly selected at days 3, 7, 14, 28 and 42 respectively, three animals each day. Then we used immunofluorescence staining to observe the distribution and duration of bevacizumab in rabbit eye tissues, and used the sandwich ELISA to quantify the concentration of free bevacizumab from the rabbit aqueous humor and vitreous after intravitreal injection. RESULTS The results show that the concentration of bevacizumab in vitreous and aqueous humor after administration of PLGA formulation was higher than that of bevacizumab solution. The T1/2 of intravitreal injection of bevacizumab-PLGA microspheres is 9.6d in vitreous and 10.2d in aqueous humor, and the T1/2 of intravitreal injection of soluble bevacizumab is 3.91d in vitreous and 4.1d in aqueous humor. There were statistical significant difference for comparison the results of the bevacizumab in vitreous and aqueous humor between the left and right eyes (P<0.05). The AUC0-t of the sustained release dosage form was 1-fold higher than that of the soluble form. The relative bioavailability was raised significantly. The immunofluorescence staining of PLGA-encapsulated bevacizumab (b-PLGA) in rabbit eye tissues was still observed up to 42d. It was longer than that of the soluble form. CONCLUSION The result of this study

  3. Clinically viable magnetic poly(lactide-co-glycolide) (PLGA) particles for MRI-based cell tracking

    PubMed Central

    Granot, Dorit; Nkansah, Michael K.; Bennewitz, Margaret F.; Tang, Kevin S.; Markakis, Eleni A.; Shapiro, Erik M.

    2013-01-01

    Purpose To design, fabricate, characterize and in vivo assay clinically viable magnetic particles for MRI-based cell tracking. Methods PLGA encapsulated magnetic nano- and microparticles were fabricated. Multiple biologically relevant experiments were performed to assess cell viability, cellular performance and stem cell differentiation. In vivo MRI experiments were performed to separately test cell transplantation and cell migration paradigms, as well as in vivo biodegradation. Results Highly magnetic nano- (~100 nm) and microparticles (~1–2 μm) were fabricated. Magnetic cell labeling in culture occurred rapidly achieving 3–50 pg Fe/cell at 3 hrs for different particles types, and >100 pg Fe/cell after 10 hours, without the requirement of a transfection agent, and with no effect on cell viability. The capability of magnetically labeled mesenchymal or neural stem cells to differentiate down multiple lineages, or for magnetically labeled immune cells to release cytokines following stimulation, was uncompromised. An in vivo biodegradation study revealed that NPs degraded ~80% over the course of 12 weeks. MRI detected as few as 10 magnetically labeled cells, transplanted into the brains of rats. Also, these particles enabled the in vivo monitoring of endogenous neural progenitor cell migration in rat brains over 2 weeks. Conclusion The robust MRI properties and benign safety profile of these particles make them promising candidates for clinical translation for MRI-based cell tracking. PMID:23568825

  4. Galactose decorated PLGA nanoparticles for hepatic delivery of acyclovir.

    PubMed

    Gupta, Swati; Agarwal, Abhinav; Gupta, Nishant Kumar; Saraogi, Gauravkant; Agrawal, Himanshu; Agrawal, G P

    2013-12-01

    The present study explores prospective of surface tailored nanoparticles for targeted delivery of acyclovir along with the interception of minimal side effects. Acyclovir loaded plain and galactosylated poly lectic co glycolic acid (PLGA) nanoparticles were efficiently prepared and characterized by Fourier transform infrared spectroscopy, scanning electron microscopy (SEM), size, polydispersity index, zeta potential, and entrapment efficiency. The formulations were evaluated for in vitro drug release and hemolysis. Further, biodistribution study and fluorescent microscopic studies were carried out to determine the targeting potential of formulations. SEM revealed smooth morphology and spherical shape of the nanoparticles. In vitro, the galactosylated nanoparticles were found to be least hemolytic and exhibited a sustained release pattern. In vivo studies exhibited an augmented bioavailability, increased residence time and enhanced delivery of acyclovir to the liver upon galactosylation. It may therefore be concluded that galactose conjugated PLGA nanoparticles can be used suitably as vehicles for delivery of bioactives specifically to the hepatic tissues and may be thus exploited in the effective management of various liver disorders.

  5. Transcellular activation of platelets and endothelial cells by bioactive lipids in platelet microparticles.

    PubMed Central

    Barry, O. P.; Pratico, D.; Lawson, J. A.; FitzGerald, G. A.

    1997-01-01

    Microparticles are released during platelet activation in vitro and have been detected in vivo in syndromes of platelet activation. They have been reported to express both pro- and anticoagulant activities. Nevertheless, their functional significance has remained unresolved. To address the mechanism(s) of cellular activation by platelet microparticles, we examined their effects on platelets and endothelial cells. Activation of human platelets by diverse stimuli (thrombin, 0.1 U/ml; collagen, 4 microg/ml; and the calcium ionophore A23187, 1 microM) results in shedding of microparticles. Pretreatment of these particles, but not membrane fractions from resting platelets, with (s)PLA2 evokes a dose-dependent increase in platelet aggregation, intracellular [Ca2+] movement, and inositol phosphate formation. These effects localize to the arachidonic acid fraction of the microparticles and are mimicked by arachidonic acid isolated from them. However, platelet activation requires prior metabolism of microparticle arachidonic acid to thromboxane A2. Thus, pretreatment of platelets with the cyclooxygenase (COX) inhibitor, indomethacin (20 microM), the thromboxane antagonist SQ29,548 (1 microM), or the protein kinase C inhibitor GF109203X (5 microM) prevents platelet activation by microparticles. However, platelet microparticles fail to evoke an inositol phosphate response directly, via either of the cloned thromboxane receptor isoforms stably expressed in human embryonic kidney (HEK) 293 cells. Prelabeling platelets with [2H(8)] arachidonate was used to demonstrate platelet metabolism of the microparticle-derived substrate to thromboxane. Platelet microparticles can also induce expression of COX-2 and prostacyclin (PGI2) production, but not expression of COX-1, in human endothelial cells. These effects are prevented by pretreatment with actinomycin D (12 microM) or cycloheximide (5 microg/ml). Expression of COX-2 is again induced by the microparticle arachidonate fraction

  6. Effect of n-HA with different surface-modified on the properties of n-HA/PLGA composite

    NASA Astrophysics Data System (ADS)

    Liuyun, Jiang; Chengdong, Xiong; Dongliang, Chen; Lixin, Jiang; xiubing, Pang

    2012-10-01

    Three different surface modification methods for nano-hydroxyapatite (n-HA) of stearic acid, grafted with L-lactide, combining stearic acid and surface-grafting L-lactic were adopted, respectively. The surface modification reaction and the effect of different methods were evaluated by Fourier transformation infrared (FTIR), X-ray photoelectron spectra (XPS), thermal gravimetric analysis (TGA), transmission electron microscopy (TEM). The results showed that n-HA surfaces were all successful modified, and the modification method of combining stearic acid and surface-grafting L-lactic had the greatest grafting amount and the best dispersion among the three modification methods. Then, the n-HA with three different surface modification and unmodified n-HA were introduced into PLGA, respectively, and a serials of n-HA/PLGA composites with 3% n-HA amount in weight were prepared by solution mixing, and the properties of n-HA/PLGA composites were also investigated by electromechanical universal tester and scanning electron microscope(SEM), comparing with PLGA. The results showed that the n-HA/PLGA composite with the n-HA surface modified by combining stearic acid and surface-grafting L-lactic had the highest bending strength and the best dispersion and interfacial adhesion among the three different modification methods, suggesting the surface modification of combining stearic acid and surface-grafting L-lactic was the most ideal method in this study, which has a great deal of enhancement of bending strength than PLGA, and it would be potential to be used in the field of bone fracture internal fixation in future.

  7. In vitro assessment of biopolymer-modified porous silicon microparticles for wound healing applications.

    PubMed

    Mori, Michela; Almeida, Patrick V; Cola, Michela; Anselmi, Giulia; Mäkilä, Ermei; Correia, Alexandra; Salonen, Jarno; Hirvonen, Jouni; Caramella, Carla; Santos, Hélder A

    2014-11-01

    The wound healing stands as very complex and dynamic process, aiming the re-establishment of the damaged tissue's integrity and functionality. Thus, there is an emerging need for developing biopolymer-based composites capable of actively promoting cellular proliferation and reconstituting the extracellular matrix. The aims of the present work were to prepare and characterize biopolymer-functionalized porous silicon (PSi) microparticles, resulting in the development of drug delivery microsystems for future applications in wound healing. Thermally hydrocarbonized PSi (THCPSi) microparticles were coated with both chitosan and a mixture of chondroitin sulfate/hyaluronic acid, and subsequently loaded with two antibacterial model drugs, vancomycin and resveratrol. The biopolymer coating, drug loading degree and drug release behavior of the modified PSi microparticles were evaluated in vitro. The results showed that both the biopolymer coating and drug loading of the THCPSi microparticles were successfully achieved. In addition, a sustained release was observed for both the drugs tested. The viability and proliferation profiles of a fibroblast cell line exposed to the modified THCPSi microparticles and the subsequent reactive oxygen species (ROS) production were also evaluated. The cytotoxicity and proliferation results demonstrated less toxicity for the biopolymer-coated THCPSi microparticles at different concentrations and time points comparatively to the uncoated counterparts. The ROS production by the fibroblasts exposed to both uncoated and biopolymer-coated PSi microparticles showed that the modified PSi microparticles did not induce significant ROS production at the concentrations tested. Overall, the biopolymer-based PSi microparticles developed in this study are promising platforms for wound healing applications.

  8. In vitro and in vivo evaluation of calcium phosphate composite scaffolds containing BMP-VEGF loaded PLGA microspheres for the treatment of avascular necrosis of the femoral head.

    PubMed

    Zhang, Hao-Xuan; Zhang, Xiu-Ping; Xiao, Gui-Yong; Hou, Yong; Cheng, Lei; Si, Meng; Wang, Shuai-Shuai; Li, Yu-Hua; Nie, Lin

    2016-03-01

    Avascular necrosis of the femoral head (ANFH) is difficult to treat due to high pressure and hypoxia, and reduced levels of growth factors such as bone morphogenetic protein (BMP), and vascular endothelial growth factor (VEGF). We generated a novel calcium phosphate (CPC) composite scaffold, which contains BMP-VEGF-loaded poly-lactic-co-glycolic acid (PLGA) microspheres (BMP-VEGF-PLGA-CPC). The BMP-VEGF-loaded microspheres have an encapsulation efficiency of 89.15% for BMP, and 78.55% for VEGF. The BMP-VEGF-PLGA-CPC scaffold also demonstrated a porosity of 62% with interconnected porous structures, and pore sizes of 219 μm and compressive strength of 6.60 MPa. Additionally, bone marrow mesenchymal stem cells (BMSCs) were seeded on scaffolds in vitro. Further characterization showed that the BMP-VEGF-PLGA-CPC scaffolds were biocompatible and enhanced osteogenesis and angiogenesis in vitro. Using a rabbit model of ANFH, BMP-VEGF-PLGA-CPC scaffolds were implanted into the bone tunnels of core decompression in the femoral head for 6 and 12 weeks. Radiographic and histological analysis demonstrated that the BMP-VEGF-PLGA-CPC scaffolds exhibited good biocompatibility, and osteogenic and angiogenic activity in vivo. These results indicate that the BMP-VEGF-PLGA-CPC scaffold may improve the therapeutic effect of core decompression surgery and be used as a treatment for ANFH.

  9. Electrospinning of PLGA/gum tragacanth nanofibers containing tetracycline hydrochloride for periodontal regeneration.

    PubMed

    Ranjbar-Mohammadi, Marziyeh; Zamani, M; Prabhakaran, M P; Bahrami, S Hajir; Ramakrishna, S

    2016-01-01

    Controlled drug release is a process in which a predetermined amount of drug is released for longer period of time, ranging from days to months, in a controlled manner. In this study, novel drug delivery devices were fabricated via blend electrospinning and coaxial electrospinning using poly lactic glycolic acid (PLGA), gum tragacanth (GT) and tetracycline hydrochloride (TCH) as a hydrophilic model drug in different compositions and their performance as a drug carrier scaffold was evaluated. Scanning electron microscopy (SEM) results showed that fabricated PLGA, blend PLGA/GT and core shell PLGA/GT nanofibers had a smooth and bead-less morphology with the diameter ranging from 180 to 460 nm. Drug release studies showed that both the fraction of GT within blend nanofibers and the core-shell structure can effectively control TCH release rate from the nanofibrous membranes. By incorporation of TCH into core-shell nanofibers, drug release was sustained for 75 days with only 19% of burst release within the first 2h. The prolonged drug release, together with proven biocompatibility, antibacterial and mechanical properties of drug loaded core shell nanofibers make them a promising candidate to be used as drug delivery system for periodontal diseases.

  10. Effect of blending HA-g-PLLA on xanthohumol-loaded PLGA fiber membrane.

    PubMed

    Qiao, Tiankui; Jiang, Suchen; Song, Ping; Song, Xiaofeng; Liu, Qimin; Wang, Lijuan; Chen, Xuesi

    2016-10-01

    Electropsun poly (lactide-co-glycolide) (PLGA) fiber membrane loaded xanthohumol (XN) has been developed using a co-solvent system of chloroform and dimethylformamide. To enhance its biological functionality as bone tissue engineering scaffolds, 5wt% hydroxyapatite grafted poly (l-lactic acid) (HA-g-PLLA) is blended into the spinning solution. The purpose of the present work is to disclose the effect of blending HA-g-PLLA on the corresponding properties of the medicated fiber membrane including morphology, thermodynamics, wettability, drug release, mechanics as well as cytotoxicity. XN and HA-g-PLLA can be well blended with PLGA to make fibers. Blending HA-g-PLLA not only turns amorphous XN/PLGA fiber membrane into crystal structure, but also changes the membranous wettability. Various medicated membranes exhibit the sustained release profiles. Drug release rate of the ternary membrane with HA-g-PLLA is slower compared to the binary XN/PLGA, and for the ternary membrane, the drug release accelerates with increasing XN content. A model is proposed to account for the drug release process. Tensile testing shows that at 10% of XN, the comprehensive mechanics of the ternary is preferable to the binary. At the same time, these fiber membranes are no cytotoxicity.

  11. PLGA-Listeriolysin O microspheres: Opening the gate for cytosolic delivery of cancer antigens.

    PubMed

    Gilert, Ariel; Baruch, Limor; Bronshtein, Tomer; Machluf, Marcelle

    2016-04-01

    Strategies for cancer protein vaccination largely aim to activate the cellular arm of the immune system against cancer cells. This approach, however, is limited since protein vaccines mostly activate the system's humoral arm instead. One way to overcome this problem is to enhance the cross-presentation of such proteins by antigen-presenting cells, which may consequently lead to intense cellular response. Here we examined the ability of listeriolysin O (LLO) incorporated into poly-lactic-co-glycolic acid (PLGA) microspheres to modify the cytosolic delivery of low molecular weight peptides and enhance their cross-presentation. PLGA microspheres were produced in a size suitable for uptake by phagocytic cells. The peptide encapsulation and release kinetics were improved by adding NaCl to the preparation. PLGA microspheres loaded with the antigenic peptide and incorporated with LLO were readily up-taken by phagocytic cells, which exhibited an increase in the expression of peptide-MHC-CI complexes on the cell surface. Furthermore, this system enhanced the activation of a specific T hybridoma cell line, thus simulating cytotoxic T cells. These results establish, for the first time, a proof of concept for the use of PLGA microspheres incorporated with a pore-forming agent and the antigen peptide of choice as a unique cancer protein vaccination delivery platform.

  12. Development and optimization of quercetin-loaded PLGA nanoparticles by experimental design

    PubMed Central

    TEFAS, LUCIA RUXANDRA; TOMUŢĂ, IOAN; ACHIM, MARCELA; VLASE, LAURIAN

    2015-01-01

    Background and aims Quercetin is a flavonoid with good antioxidant activity, and exhibits various important pharmacological effects. The aim of the present work was to study the influence of formulation factors on the physicochemical properties of quercetin-loaded polymeric nanoparticles in order to optimize the formulation. Materials and methods The nanoparticles were prepared by the nanoprecipitation method. A 3-factor, 3-level Box-Behnken design was employed in this study considering poly(D,L-lactic-co-glycolic) acid (PLGA) concentration, polyvinyl alcohol (PVA) concentration and the stirring speed as independent variables. The responses were particle size, polydispersity index, zeta potential and encapsulation efficiency. Results The PLGA concentration seemed to be the most important factor influencing quercetin-nanoparticle characteristics. Increasing PLGA concentration led to an increase in particle size, as well as encapsulation efficiency. On the other hand, it exhibited a negative influence on the polydispersity index and zeta potential. The PVA concentration and the stirring speed had only a slight influence on particle size and polydispersity index. However, PVA concentration had an important negative effect on the encapsulation efficiency. Based on the results obtained, an optimized formulation was prepared, and the experimental values were comparable to the predicted ones. Conclusions The overall results indicated that PLGA concentration was the main factor influencing particle size, while entrapment efficiency was predominantly affected by the PVA concentration. PMID:26528074

  13. Internalization and cytotoxicity analysis of silicon-based microparticles in macrophages and embryos.

    PubMed

    Fernández-Rosas, Elisabet; Gómez, Rodrigo; Ibañez, Elena; Barrios, Lleonard; Duch, Marta; Esteve, Jaume; Plaza, José A; Nogués, Carme

    2010-06-01

    Microchips can be fabricated, using semiconductor technologies, at microscopic level to be introduced into living cells for monitoring of intracellular parameters at a single cell level. As a first step towards intracellular chips development, silicon and polysilicon microparticles of controlled shape and dimensions were fabricated and introduced into human macrophages and mouse embryos by phagocytosis and microinjection, respectively. Microparticles showed to be non-cytotoxic for macrophages and were found to be localized mainly inside early endosomes, in tight association with endosomal membrane, and more rarely in acidic compartments. Embryos with microinjected microparticles developed normally to the blastocyst stage, confirming the non-cytotoxic effect of the particles. In view of these results silicon and polysilicon microparticles can serve as the frame for future intracellular chips development and this technology opens the possibility of real complex devices to be used as sensors or actuators inside living cells.

  14. Docetaxel-loaded PLGA and PLGA-PEG nanoparticles for intravenous application: pharmacokinetics and biodistribution profile

    PubMed Central

    Rafiei, Pedram; Haddadi, Azita

    2017-01-01

    Docetaxel is a highly potent anticancer agent being used in a wide spectrum of cancer types. There are important matters of concern regarding the drug’s pharmacokinetics related to the conventional formulation. Poly(lactide-co-glycolide) (PLGA) is a biocompatible/biodegradable polymer with variable physicochemical characteristics, and its application in human has been approved by the United States Food and Drug Administration. PLGA gives polymeric nanoparticles with unique drug delivery characteristics. The application of PLGA nanoparticles (NPs) as intravenous (IV) sustained-release delivery vehicles for docetaxel can favorably modify pharmacokinetics, biofate, and pharmacotherapy of the drug in cancer patients. Surface modification of PLGA NPs with poly(ethylene glycol) (PEG) can further enhance NPs’ long-circulating properties. Herein, an optimized fabrication approach has been used for the preparation of PLGA and PLGA–PEG NPs loaded with docetaxel for IV application. Both types of NP formulations demonstrated in vitro characteristics that were considered suitable for IV administration (with long-circulating sustained-release purposes). NP formulations were IV administered to an animal model, and docetaxel’s pharmacokinetic and biodistribution profiles were determined and compared between study groups. PLGA and PEGylated PLGA NPs were able to modify the pharmacokinetics and biodistribution of docetaxel. Accordingly, the mode of changes made to pharmacokinetics and biodistribution of docetaxel is attributed to the size and surface properties of NPs. NPs contributed to increased blood residence time of docetaxel fulfilling their role as long-circulating sustained-release drug delivery systems. Surface modification of NPs contributed to more pronounced docetaxel blood concentration, which confirms the role of PEG in conferring long-circulation properties to NPs. PMID:28184163

  15. mZD7349 peptide-conjugated PLGA nanoparticles directed against VCAM-1 for targeted delivery of simvastatin to restore dysfunctional HUVECs.

    PubMed

    Imanparast, Fatemeh; Faramarzi, Mohammad Ali; Vatannejad, Akram; Paknejad, Maliheh; Deiham, Behnas; Kobarfard, Farzad; Amani, Amir; Doosti, Mahmood

    2017-02-02

    Endothelial dysfunction is initial and critical step of atherosclerosis. Impaired bioavailability of endothelial nitric oxide synthase (eNOS) is one of the main reasons of endothelial dysfunction. Improving bioavailability of eNOS by increasing its expression or activity using statins is an effective therapeutic strategy in restoring endothelial dysfunction. In this study, simvastatin (SIM) as a poorly water-soluble drug was loaded in poly (lactic-co-glycolic acid) (PLGA) nanoparticles (SIM-PLGA-NPs). NPs were then conjugated with mZD7349 peptide (mZD7349-SIM-PLGA-NPs) and directed against vascular cell adhesion molecule 1 (VCAM-1). In vitro evaluation of the NPs for targeted delivery of SIM was performed on activated Human Umbilical Cord Vascular Endothelial Cells (HUVECs) by tumor necrosis factor alpha (TNF-α). Effect of mZD7349-SIM-PLGA-NPs and SIM-PLGA-NPs was compared on eNOS phosphorylation (ser-1177). Results of western blot showed SIM post-treatment increased significantly phosphor-eNOS (Ser1177) expression but no total eNOS expression. The study showed that mZD7349-SIM-PLGA-NPs have particle size, zeta potential value, polydispersity index (PDI) and encapsulation efficacy % of 233±18nm, -9.6±1.1mV, 0.59±0.066 and 69±17.3%, respectively. Also phosphor-eNOS (Ser1177) expression in activated HUVECs treated with mZD7349-SIM-PLGA-NPs was significantly (p<0.05) better than treated cells with SIM-PLGA-NPs. The results suggest that mZD7349-SIM-PLGA-NPs may be usable as an appropriate drug carrier for restoring endothelial dysfunction.

  16. Microparticles as Potential Biomarkers of Cardiovascular Disease

    PubMed Central

    França, Carolina Nunes; Izar, Maria Cristina de Oliveira; do Amaral, Jônatas Bussador; Tegani, Daniela Melo; Fonseca, Francisco Antonio Helfenstein

    2015-01-01

    Primary prevention of cardiovascular disease is a choice of great relevance because of its impact on health. Some biomarkers, such as microparticles derived from different cell populations, have been considered useful in the assessment of cardiovascular disease. Microparticles are released by the membrane structures of different cell types upon activation or apoptosis, and are present in the plasma of healthy individuals (in levels considered physiological) and in patients with different pathologies. Many studies have suggested an association between microparticles and different pathological conditions, mainly the relationship with the development of cardiovascular diseases. Moreover, the effects of different lipid-lowering therapies have been described in regard to measurement of microparticles. The studies are still controversial regarding the levels of microparticles that can be considered pathological. In addition, the methodologies used still vary, suggesting the need for standardization of the different protocols applied, aiming at using microparticles as biomarkers in clinical practice. PMID:25626759

  17. Method for determining surface properties of microparticles

    DOEpatents

    Eisenthal, Kenneth B.

    2000-01-01

    Second harmonic generation (SHG), sum frequency generation (SFG) and difference frequency generation (DFG) can be used for surface analysis or characterization of microparticles having a non-metallic surface feature. The microparticles can be centrosymmetric or such that non-metallic molecules of interest are centrosymmetrically distributed inside and outside the microparticles but not at the surface of the microparticles where the asymmetry aligns the molecules. The signal is quadratic in incident laser intensity or proportional to the product of two incident laser intensities for SFG, it is sharply peaked at the second harmonic wavelength, quadratic in the density of molecules adsorbed onto the microparticle surface, and linear in microparticles density. In medical or pharmacological applications, molecules of interest may be of drugs or toxins, for example.

  18. Computational Intelligence Modeling of the Macromolecules Release from PLGA Microspheres-Focus on Feature Selection.

    PubMed

    Zawbaa, Hossam M; Szlȩk, Jakub; Grosan, Crina; Jachowicz, Renata; Mendyk, Aleksander

    2016-01-01

    Poly-lactide-co-glycolide (PLGA) is a copolymer of lactic and glycolic acid. Drug release from PLGA microspheres depends not only on polymer properties but also on drug type, particle size, morphology of microspheres, release conditions, etc. Selecting a subset of relevant properties for PLGA is a challenging machine learning task as there are over three hundred features to consider. In this work, we formulate the selection of critical attributes for PLGA as a multiobjective optimization problem with the aim of minimizing the error of predicting the dissolution profile while reducing the number of attributes selected. Four bio-inspired optimization algorithms: antlion optimization, binary version of antlion optimization, grey wolf optimization, and social spider optimization are used to select the optimal feature set for predicting the dissolution profile of PLGA. Besides these, LASSO algorithm is also used for comparisons. Selection of crucial variables is performed under the assumption that both predictability and model simplicity are of equal importance to the final result. During the feature selection process, a set of input variables is employed to find minimum generalization error across different predictive models and their settings/architectures. The methodology is evaluated using predictive modeling for which various tools are chosen, such as Cubist, random forests, artificial neural networks (monotonic MLP, deep learning MLP), multivariate adaptive regression splines, classification and regression tree, and hybrid systems of fuzzy logic and evolutionary computations (fugeR). The experimental results are compared with the results reported by Szlȩk. We obtain a normalized root mean square error (NRMSE) of 15.97% versus 15.4%, and the number of selected input features is smaller, nine versus eleven.

  19. In vivo uptake and acute immune response to orally administered chitosan and PEG coated PLGA nanoparticles

    SciTech Connect

    Semete, B.; Booysen, L.I.J.; Kalombo, L.; Venter, J.D.; Katata, L.; Ramalapa, B.; Verschoor, J.A.; Swai, H.

    2010-12-01

    Nanoparticulate drug delivery systems offer great promise in addressing challenges of drug toxicity, poor bioavailability and non-specificity for a number of drugs. Much progress has been reported for nano drug delivery systems for intravenous administration, however very little is known about the effects of orally administered nanoparticles. Furthermore, the development of nanoparticulate systems necessitates a thorough understanding of the biological response post exposure. This study aimed to elucidate the in vivo uptake of chitosan and polyethylene glycol (PEG) coated Poly, DL, lactic-co-glycolic Acid (PLGA) nanoparticles and the immunological response within 24 h of oral and peritoneal administration. These PLGA nanoparticles were administered orally and peritoneally to female Balb/C mice, they were taken up by macrophages of the peritoneum. When these particles were fluorescently labelled, intracellular localisation was observed. The expression of pro-inflammatory cytokines IL-2, IL-6, IL-12p70 and TNF-{alpha} in plasma and peritoneal lavage was found to remain at low concentration in PLGA nanoparticles treated mice as well as ZnO nanoparticles during the 24 hour period. However, these were significantly increased in lipopolysaccharide (LPS) treated mice. Of these pro-inflammatory cytokines, IL-6 and IL-12p70 were produced at the highest concentration in the positive control group. The anti-inflammatory cytokines IL-10 and chemokines INF-{gamma}, IL-4, IL-5 remained at normal levels in PLGA treated mice. IL-10 and INF-{gamma} were significantly increased in LPS treated mice. MCP-1 was found to be significantly produced in all groups in the first hours, except the saline treated mice. These results provide the first report to detail the induction of cytokine production by PLGA nanoparticles engineered for oral applications.

  20. Computational Intelligence Modeling of the Macromolecules Release from PLGA Microspheres—Focus on Feature Selection

    PubMed Central

    Zawbaa, Hossam M.; Szlȩk, Jakub; Grosan, Crina; Jachowicz, Renata; Mendyk, Aleksander

    2016-01-01

    Poly-lactide-co-glycolide (PLGA) is a copolymer of lactic and glycolic acid. Drug release from PLGA microspheres depends not only on polymer properties but also on drug type, particle size, morphology of microspheres, release conditions, etc. Selecting a subset of relevant properties for PLGA is a challenging machine learning task as there are over three hundred features to consider. In this work, we formulate the selection of critical attributes for PLGA as a multiobjective optimization problem with the aim of minimizing the error of predicting the dissolution profile while reducing the number of attributes selected. Four bio-inspired optimization algorithms: antlion optimization, binary version of antlion optimization, grey wolf optimization, and social spider optimization are used to select the optimal feature set for predicting the dissolution profile of PLGA. Besides these, LASSO algorithm is also used for comparisons. Selection of crucial variables is performed under the assumption that both predictability and model simplicity are of equal importance to the final result. During the feature selection process, a set of input variables is employed to find minimum generalization error across different predictive models and their settings/architectures. The methodology is evaluated using predictive modeling for which various tools are chosen, such as Cubist, random forests, artificial neural networks (monotonic MLP, deep learning MLP), multivariate adaptive regression splines, classification and regression tree, and hybrid systems of fuzzy logic and evolutionary computations (fugeR). The experimental results are compared with the results reported by Szlȩk. We obtain a normalized root mean square error (NRMSE) of 15.97% versus 15.4%, and the number of selected input features is smaller, nine versus eleven. PMID:27315205

  1. Two-step nanoprecipitation for the production of protein-loaded PLGA nanospheres

    PubMed Central

    Morales-Cruz, Moraima; Flores-Fernández, Giselle M.; Morales-Cruz, Myreisa; Orellano, Elsie A.; Rodriguez-Martinez, José A.; Ruiz, Mercedes; Griebenow, Kai

    2012-01-01

    One of the first methods to encapsulate drugs within polymer nanospheres was developed by Fessi and coworkers in 1989 and consisted of one-step nanoprecipitation based on solvent displacement. However, proteins are poorly encapsulated within polymer nanoparticles using this method because of their limited solubility in organic solvents. To overcome this limitation, we developed a two-step nanoprecipitation method and encapsulated various proteins with high efficiency into poly(lactic-co-glycolic)acid (PLGA) nanospheres (NP). In this method, a protein nanoprecipitation step is used first followed by a second polymer nanoprecipitation step. Two model enzymes, lysozyme and α-chymotrypsin, were used for the optimization of the method. We obtained encapsulation efficiencies of >70%, an amount of buffer-insoluble protein aggregates of typically <2%, and a high residual activity of typically >90%. The optimum conditions identified for lysozyme were used to successfully encapsulate cytochrome c(Cyt-c), an apoptosis-initiating basic protein of similar size, to verify reproducibility of the encapsulation procedure. The size of the Cyt-c loaded-PLGA nanospheres was around 300–400 nm indicating the potential of the delivery system to passively target tumors. Cell viability studies, using a human cervical cancer cell line (HeLa), demonstrate excellent biocompatibility of the PLGA nanoparticles. PLGA nanoparticles carrying encapsulated Cyt-c were not efficient in causing apoptosis presumably because PLGA nanoparticles are not efficiently taken up by the cells. Future systems will have to be optimized to ascertain efficient cellular uptake of the nanoparticles by, e.g., surface modification with receptor ligands. PMID:23316451

  2. RGD peptide-displaying M13 bacteriophage/PLGA nanofibers as cell-adhesive matrices for smooth muscle cells

    NASA Astrophysics Data System (ADS)

    Shin, Yong Cheol; Lee, Jong Ho; Jin, Oh Seong; Lee, Eun Ji; Jin, Lin Hua; Kim, Chang-Seok; Hong, Suck Won; Han, Dong-Wook; Kim, Chuntae; Oh, Jin-Woo

    2015-01-01

    Extracellular matrices (ECMs) are network structures that play an essential role in regulating cellular growth and differentiation. In this study, novel nanofibrous matrices were fabricated by electrospinning M13 bacteriophage and poly(lactic- co-glycolic acid) (PLGA) and were shown to be structurally and functionally similar to natural ECMs. A genetically-engineered M13 bacteriophage was constructed to display Arg-Gly-Asp (RGD) peptides on its surface. The physicochemical properties of RGD peptide-displaying M13 bacteriophage (RGD-M13 phage)/PLGA nanofibers were characterized by using scanning electron microscopy and Fourier-transform infrared spectroscopy. We used immunofluorescence staining to confirm that M13 bacteriophages were homogenously distributed in RGD-M13 phage/PLGA matrices. Furthermore, RGD-M13 phage/PLGA nanofibrous matrices, having excellent biocompatibility, can enhance the behaviors of vascular smooth muscle cells. This result suggests that RGD-M13 phage/PLGA nanofibrous matrices have potentials to serve as tissue engineering scaffolds.

  3. The use of BMP-2 coupled - Nanosilver-PLGA composite grafts to induce bone repair in grossly infected segmental defects.

    PubMed

    Zheng, Zhong; Yin, Wei; Zara, Janette N; Li, Weiming; Kwak, Jinny; Mamidi, Rachna; Lee, Min; Siu, Ronald K; Ngo, Richard; Wang, Joyce; Carpenter, Doug; Zhang, Xinli; Wu, Benjamin; Ting, Kang; Soo, Chia

    2010-12-01

    Healing of contaminated/infected bone defects is a significant clinical challenge. Prevalence of multi-antibiotic resistant organisms has renewed interest in the use of antiseptic silver as an effective, but less toxic antimicrobial with decreased potential for bacterial resistance. In this study, we demonstrated that metallic nanosilver particles (with a size of 20-40nm)-poly(lactic-co-glycolic acid) (PLGA) composite grafts have strong antibacterial properties. In addition, nanosilver particles-PLGA composite grafts did not inhibit adherence, proliferation, alkaline phosphatase activity, or mineralization of ongrowth MC3T3-E1 pre-osteoblasts compared to PLGA controls. Furthermore, nanosilver particles did not affect the osteoinductivity of bone morphogenetic protein 2 (BMP-2). Infected femoral defects implanted with BMP-2 coupled 2.0% nanosilver particles-PLGA composite grafts healed in 12 weeks without evidence of residual bacteria. In contrast, BMP-2 coupled PLGA control grafts failed to heal in the presence of continued bacterial colonies. Our results indicate that nanosilver of defined particle size is bactericidal without discernable in vitro and in vivo cytotoxicity or negative effects on BMP-2 osteoinductivity, making it an ideal antimicrobial for bone regeneration in infected wounds.

  4. A mechanistic model for drug release in PLGA biodegradable stent coatings coupled with polymer degradation and erosion.

    PubMed

    Zhu, Xiaoxiang; Braatz, Richard D

    2015-07-01

    Biodegradable poly(d,l-lactic-co-glycolic acid) (PLGA) coating for applications in drug-eluting stents has been receiving increasing interest as a result of its unique properties compared with biodurable polymers in delivering drug for reducing stents-related side effects. In this work, a mathematical model for describing the PLGA degradation and erosion and coupled drug release from PLGA stent coating is developed and validated. An analytical expression is derived for PLGA mass loss that predicts multiple experimental studies in the literature. An analytical model for the change of the number-average degree of polymerization [or molecular weight (MW)] is also derived. The drug transport model incorporates simultaneous drug diffusion through both the polymer solid and the liquid-filled pores in the coating, where an effective drug diffusivity model is derived taking into account factors including polymer MW change, stent coating porosity change, and drug partitioning between solid and aqueous phases. The model is used to describe in vitro sirolimus release from PLGA stent coating, and demonstrates the significance of simultaneous sirolimus release via diffusion through both polymer solid and pore space. The proposed model is compared to existing drug transport models, and the impact of model parameters, limitations and possible extensions of the model are also discussed.

  5. A three-layered nano-carbonated hydroxyapatite/collagen/PLGA composite membrane for guided tissue regeneration.

    PubMed

    Liao, Susan; Wang, Wei; Uo, Motohiro; Ohkawa, Shoji; Akasaka, Tsukasa; Tamura, Kazuchika; Cui, Fuzhai; Watari, Fumio

    2005-12-01

    Functional graded materials (FGM) provided us one new concept for guided tissue regeneration (GTR) membrane design with graded component and graded structure where one face of the membrane is porous thereby allowing cell growth thereon and the opposite face of the membrane is smooth, thereby inhibiting cell adhesion in periodontal therapy. The goal of the present study was to develop a three-layered graded membrane, with one face of 8% nano-carbonated hydroxyapatite/collagen/poly(lactic-co-glycolic acid) (nCHAC/PLGA) porous membrane, the opposite face of pure PLGA non-porous membrane, the middle layer of 4% nCHAC/PLGA as the transition through layer-by-layer casting method. Then the three layers were combined well with each other with flexibility and enough high mechanical strength as membrane because the three layers all contained PLGA polymer that can be easily used for practical medical application. This high biocompatibility and osteoconductivity of this biodegraded composite membrane was enhanced by the nCHAC addition, for the same component and nano-level crystal size with natural bone tissue. The osteoblastic MC3T3-E1 cells were cultured on the three-layered composite membrane, the primary result shows the positive response compared with pure PLGA membrane.

  6. Effects of gatifloxaine content in gatifloxacine-loaded PLGA and β-tricalcium phosphate composites on efficacy in treating osteomyelitis.

    PubMed

    Kimishima, Kaori; Matsuno, Tomonori; Makiishi, Jun; Tamazawa, Gaku; Sogo, Yu; Ito, Atsuo; Satoh, Tazuko

    2016-01-01

    Composites of gatifloxacin (GFLX)-loaded poly (lactic-co-glycolic) acid (PLGA) and β-tricalcium phosphate (βTCP) containing 0, 1, and 10 wt % GFLX (0, 1, and 10 wt % GFLX composites), and GFLX-loaded PLGA containing 1, 5, and 10 wt % GFLX (1, 5, and 10wt % GFLX-PLGA) as controls were fabricated and characterized in vitro and in vivo. On in vitro evaluation, the 10 wt % GFLX composite released GFLX over at least 28 days in Hanks' balanced solution and exhibited clinically sufficient bactericidal activities against Streptococcus milleri and Bacteroides fragilis from 1 h to 10 days. The 0, 1, and 10 wt % GFLX composites and 10 wt % GFLX-PLGA were implanted in bone defects created by debridement of osteomyelitis lesions induced by S. milleri and B. fragilis in the mandible of rabbits (n = 5). Four weeks after implantation of the 10 wt % GFLX composite, inflammation in the debrided area disappeared in all the rabbits, while inflammation remained in all the rabbits after implantation of the 0 wt % GFLX composite and 10 wt % GFLX-PLGA, and in three rabbits after implantation of the 1 wt % GFLX composite. Bone formation appears to be less intense for the 10 wt % GFLX composite than for the 1 wt % GFLX composite probably owing to the rapid degradation of the 10 wt % GFLX composite. These findings show that the GFLX composite is effective for the local treatment of osteomyelitis.

  7. Thermodynamic Insights and Conceptual Design of Skin-Sensitive Chitosan Coated Ceramide/PLGA Nanodrug for Regeneration of Stratum Corneum on Atopic Dermatitis

    PubMed Central

    Jung, Sang-Myung; Yoon, Gwang Heum; Lee, Hoo Chul; Jung, Moon Hee; Yu, Sun Il; Yeon, Seung Ju; Min, Seul Ki; Kwon, Yeo Seon; Hwang, Jin Ha; Shin, Hwa Sung

    2015-01-01

    Atopic dermatitis (AD) is a complex skin disease primarily characterized by psoriasis of the stratum corneum. AD drugs have usually been used in acidic and hydrophilic solvents to supply moisture and prevent lipid defects. Ceramide is a typical treatment agent to regenerate the stratum corneum and relieve symptoms of AD. However, ceramide has limitation on direct use for skin because of its low dispersion properties in hydrophilic phase and side effects at excessive treatment. In this study, ceramide imbedded PLGA nanoparticles were developed with chitosan coating (Chi-PLGA/Cer) to overcome this problem. The chitosan coating enhanced initial adherence to the skin and prevented the initial burst of ceramide, but was degraded by the weakly acidic nature of skin, resulting in controlled release of ceramide with additional driving force of the squeezed PLGA nanoparticles. Additionally, the coating kinetics of chitosan were controlled by manipulating the reaction conditions and then mathematically modeled. The Chi-PLGA/Cer was not found to be cytotoxic and ceramide release was controlled by pH, temperature, and chitosan coating. Finally, Chi-PLGA/Cer was demonstrated to be effective at stratum corneum regeneration in a rat AD model. Overall, the results presented herein indicated that Chi-PLGA/Cer is a novel nanodrug for treatment of AD. PMID:26666701

  8. Thermodynamic Insights and Conceptual Design of Skin-Sensitive Chitosan Coated Ceramide/PLGA Nanodrug for Regeneration of Stratum Corneum on Atopic Dermatitis.

    PubMed

    Jung, Sang-Myung; Yoon, Gwang Heum; Lee, Hoo Chul; Jung, Moon Hee; Yu, Sun Il; Yeon, Seung Ju; Min, Seul Ki; Kwon, Yeo Seon; Hwang, Jin Ha; Shin, Hwa Sung

    2015-12-15

    Atopic dermatitis (AD) is a complex skin disease primarily characterized by psoriasis of the stratum corneum. AD drugs have usually been used in acidic and hydrophilic solvents to supply moisture and prevent lipid defects. Ceramide is a typical treatment agent to regenerate the stratum corneum and relieve symptoms of AD. However, ceramide has limitation on direct use for skin because of its low dispersion properties in hydrophilic phase and side effects at excessive treatment. In this study, ceramide imbedded PLGA nanoparticles were developed with chitosan coating (Chi-PLGA/Cer) to overcome this problem. The chitosan coating enhanced initial adherence to the skin and prevented the initial burst of ceramide, but was degraded by the weakly acidic nature of skin, resulting in controlled release of ceramide with additional driving force of the squeezed PLGA nanoparticles. Additionally, the coating kinetics of chitosan were controlled by manipulating the reaction conditions and then mathematically modeled. The Chi-PLGA/Cer was not found to be cytotoxic and ceramide release was controlled by pH, temperature, and chitosan coating. Finally, Chi-PLGA/Cer was demonstrated to be effective at stratum corneum regeneration in a rat AD model. Overall, the results presented herein indicated that Chi-PLGA/Cer is a novel nanodrug for treatment of AD.

  9. Development of biodegradable methylprednisolone microparticles for treatment of articular pathology using a spray-drying technique

    PubMed Central

    Tobar-Grande, Blanca; Godoy, Ricardo; Bustos, Paulina; von Plessing, Carlos; Fattal, Elias; Tsapis, Nicolas; Olave, Claudia; Gómez-Gaete, Carolina

    2013-01-01

    In this work, microparticles were prepared by spray-drying using albumin, chondroitin sulfate, and hyaluronic acid as excipients to create a controlled-release methylprednisolone system for use in inflammatory disorders such as arthritis. Scanning electron microscopy demonstrated that these microparticles were almost spherical, with development of surface wrinkling as the methylprednisolone load in the formulation was increased. The methylprednisolone load also had a direct influence on the mean diameter and zeta potential of the microparticles. Interactions between formulation excipients and the active drug were evaluated by x-ray diffraction, differential scanning calorimetry, and thermal gravimetric analysis, showing limited amounts of methylprednisolone in a crystalline state in the loaded microparticles. The encapsulation efficiency of methylprednisolone was approximately 89% in all formulations. The rate of methylprednisolone release from the microparticles depended on the initial drug load in the formulation. In vitro cytotoxic evaluation using THP-1 cells showed that none of the formulations prepared triggered an inflammatory response on release of interleukin-1β, nor did they affect cellular viability, except for the 9.1% methylprednisolone formulation, which was the maximum test concentration used. The microparticles developed in this study have characteristics amenable to a therapeutic role in inflammatory pathology, such as arthritis. PMID:23737670

  10. Development of biodegradable methylprednisolone microparticles for treatment of articular pathology using a spray-drying technique.

    PubMed

    Tobar-Grande, Blanca; Godoy, Ricardo; Bustos, Paulina; von Plessing, Carlos; Fattal, Elias; Tsapis, Nicolas; Olave, Claudia; Gómez-Gaete, Carolina

    2013-01-01

    In this work, microparticles were prepared by spray-drying using albumin, chondroitin sulfate, and hyaluronic acid as excipients to create a controlled-release methylprednisolone system for use in inflammatory disorders such as arthritis. Scanning electron microscopy demonstrated that these microparticles were almost spherical, with development of surface wrinkling as the methylprednisolone load in the formulation was increased. The methylprednisolone load also had a direct influence on the mean diameter and zeta potential of the microparticles. Interactions between formulation excipients and the active drug were evaluated by x-ray diffraction, differential scanning calorimetry, and thermal gravimetric analysis, showing limited amounts of methylprednisolone in a crystalline state in the loaded microparticles. The encapsulation efficiency of methylprednisolone was approximately 89% in all formulations. The rate of methylprednisolone release from the microparticles depended on the initial drug load in the formulation. In vitro cytotoxic evaluation using THP-1 cells showed that none of the formulations prepared triggered an inflammatory response on release of interleukin-1β, nor did they affect cellular viability, except for the 9.1% methylprednisolone formulation, which was the maximum test concentration used. The microparticles developed in this study have characteristics amenable to a therapeutic role in inflammatory pathology, such as arthritis.

  11. PHBV/PCL Microparticles for Controlled Release of Resveratrol: Physicochemical Characterization, Antioxidant Potential, and Effect on Hemolysis of Human Erythrocytes

    PubMed Central

    Mendes, Jessica Bitencourt Emilio; Riekes, Manoela Klüppel; de Oliveira, Viviane Matoso; Michel, Milton Domingos; Stulzer, Hellen Karine; Khalil, Najeh Maissar; Zawadzki, Sônia Faria; Mainardes, Rubiana Mara; Farago, Paulo Vitor

    2012-01-01

    Microparticles of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) and poly(ε-caprolactone) (PCL) containing resveratrol were successfully prepared by simple emulsion/solvent evaporation. All formulations showed suitable encapsulation efficiency values higher than 80%. PHBV microparticles revealed spherical shape with rough surface and presence of pores. PCL microparticles were spherically shaped with smooth surface. Fourier-transformed infrared spectra demonstrated no chemical bond between resveratrol and polymers. X-ray powder diffraction patterns and differential scanning calorimetry analyses indicated that microencapsulation led to drug amorphization. These PHBV/PCL microparticles delayed the dissolution profile of resveratrol. Release profiles were better fitted to biexponential equation. The hypochlorous-acid-scavenging activity and 2,2-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) radical cation discoloration assay confirmed that the antioxidant activity of PHBV/PCL microparticles was kept, but was dependent on the microparticle morphology and dissolution profile. Resveratrol-loaded PHBV/PCL microparticles showed no cytotoxic effect on red blood cells. PMID:22666135

  12. PHBV/PCL microparticles for controlled release of resveratrol: physicochemical characterization, antioxidant potential, and effect on hemolysis of human erythrocytes.

    PubMed

    Mendes, Jessica Bitencourt Emilio; Riekes, Manoela Klüppel; de Oliveira, Viviane Matoso; Michel, Milton Domingos; Stulzer, Hellen Karine; Khalil, Najeh Maissar; Zawadzki, Sônia Faria; Mainardes, Rubiana Mara; Farago, Paulo Vitor

    2012-01-01

    Microparticles of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) and poly(ε-caprolactone) (PCL) containing resveratrol were successfully prepared by simple emulsion/solvent evaporation. All formulations showed suitable encapsulation efficiency values higher than 80%. PHBV microparticles revealed spherical shape with rough surface and presence of pores. PCL microparticles were spherically shaped with smooth surface. Fourier-transformed infrared spectra demonstrated no chemical bond between resveratrol and polymers. X-ray powder diffraction patterns and differential scanning calorimetry analyses indicated that microencapsulation led to drug amorphization. These PHBV/PCL microparticles delayed the dissolution profile of resveratrol. Release profiles were better fitted to biexponential equation. The hypochlorous-acid-scavenging activity and 2,2-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) radical cation discoloration assay confirmed that the antioxidant activity of PHBV/PCL microparticles was kept, but was dependent on the microparticle morphology and dissolution profile. Resveratrol-loaded PHBV/PCL microparticles showed no cytotoxic effect on red blood cells.

  13. Surface-assembled poly(I:C) on PEGylated PLGA microspheres as vaccine adjuvant: APC activation and bystander cell stimulation.

    PubMed

    Hafner, Annina M; Corthésy, Blaise; Textor, Marcus; Merkle, Hans P

    2016-11-30

    Biodegradable poly(lactic-co-glycolic acid) (PLGA) microspheres are potential vehicles to deliver antigens for vaccination. Because they lack the full capacity to activate professional antigen presenting cells (APCs), combination with an immunostimulatory adjuvant may be considered. A candidate is the synthetic TLR3 ligand polyriboinosinic acid-polyribocytidylic acid, poly(I:C), which drives cell-mediated immunity. However, poly(I:C) has also been linked to the pathogenesis of autoimmunity, as affected by widespread stimulation of non-hematopoietic bystander cells. To address this aspect, we propose to minimize the poly(I:C) dose as well as to control the stimulation of non-immune bystander cells by poly(I:C). To facilitate the maturation of APCs with minimal poly(I:C) doses, we surface-assembled poly(I:C) onto PLGA microspheres. The microspheres' surface was further modified by poly(ethylene glycol) (PEG) coronas with varying PEG-densities. PLGA microspheres loaded with tetanus toxoid (tt) as model antigen were manufactured by microextrusion-based solvent extraction. The negatively charged PLGA(tt) microspheres were coated with polycationic poly(l-lysine) (PLL) polymers, either PLL itself or PEG-grafted PLL (PLL-g-PEG) with varying grafting ratios (g=2.2 and g=10.1). Stable surface assembly of poly(I:C) was achieved by subsequent incubation of polymer-coated PLGA microspheres with aqueous poly(I:C) solutions. We evaluated the immunostimulatory potential of such PLGA(tt) microsphere formulations on monocyte-derived dendritic cells (MoDCs) as well as human foreskin fibroblasts (HFFs) as model for non-hematopoietic bystander cells. Formulations with surface-assembled poly(I:C) readily activated MoDCs with respect to the expression of maturation-related surface markers, proinflammatory cytokine secretion and directed migration. When surface-assembled, poly(I:C) enhanced its immunostimulatory activity by more than one order of magnitude as compared to free poly

  14. Tandem mass spectrometry of individual airborne microparticles

    SciTech Connect

    Reilly, P.T.A.; Gieray, R.A.; Yang, M.; Whitten, W.B.; Ramsey, J.M.

    1997-01-01

    An apparatus for real-time MS/MS analysis of individual airborne microparticles by laser ablation in an ion trap is described. The performance has been demonstrated by the detection of tributyl phosphate and bis(2-ethylhexyl) phosphate on silicon carbide and kaolin microparticles. 28 refs., 5 figs.

  15. PLGA nanoparticle encapsulation reduces toxicity while retaining the therapeutic efficacy of EtNBS-PDT in vitro

    PubMed Central

    Hung, Hsin-I; Klein, Oliver J.; Peterson, Sam W.; Rokosh, Sarah R.; Osseiran, Sam; Nowell, Nicholas H.; Evans, Conor L.

    2016-01-01

    Photodynamic therapy regimens, which use light-activated molecules known as photosensitizers, are highly selective against many malignancies and can bypass certain challenging therapeutic resistance mechanisms. Photosensitizers such as the small cationic molecule EtNBS (5-ethylamino-9-diethyl-aminobenzo[a]phenothiazinium chloride) have proven potent against cancer cells that reside within acidic and hypoxic tumour microenvironments. At higher doses, however, these photosensitizers induce “dark toxicity” through light-independent mechanisms. In this study, we evaluated the use of nanoparticle encapsulation to overcome this limitation. Interestingly, encapsulation of the compound within poly(lactic-co-glycolic acid) (PLGA) nanoparticles (PLGA-EtNBS) was found to significantly reduce EtNBS dark toxicity while completely retaining the molecule’s cytotoxicity in both normoxic and hypoxic conditions. This dual effect can be attributed to the mechanism of release: EtNBS remains encapsulated until external light irradiation, which stimulates an oxygen-independent, radical-mediated process that degrades the PLGA nanoparticles and releases the molecule. As these PLGA-encapsulated EtNBS nanoparticles are capable of penetrating deeply into the hypoxic and acidic cores of 3D spheroid cultures, they may enable the safe and efficacious treatment of otherwise unresponsive tumour regions. PMID:27686626

  16. PLGA nanoparticle encapsulation reduces toxicity while retaining the therapeutic efficacy of EtNBS-PDT in vitro

    NASA Astrophysics Data System (ADS)

    Hung, Hsin-I.; Klein, Oliver J.; Peterson, Sam W.; Rokosh, Sarah R.; Osseiran, Sam; Nowell, Nicholas H.; Evans, Conor L.

    2016-09-01

    Photodynamic therapy regimens, which use light-activated molecules known as photosensitizers, are highly selective against many malignancies and can bypass certain challenging therapeutic resistance mechanisms. Photosensitizers such as the small cationic molecule EtNBS (5-ethylamino-9-diethyl-aminobenzo[a]phenothiazinium chloride) have proven potent against cancer cells that reside within acidic and hypoxic tumour microenvironments. At higher doses, however, these photosensitizers induce “dark toxicity” through light-independent mechanisms. In this study, we evaluated the use of nanoparticle encapsulation to overcome this limitation. Interestingly, encapsulation of the compound within poly(lactic-co-glycolic acid) (PLGA) nanoparticles (PLGA-EtNBS) was found to significantly reduce EtNBS dark toxicity while completely retaining the molecule’s cytotoxicity in both normoxic and hypoxic conditions. This dual effect can be attributed to the mechanism of release: EtNBS remains encapsulated until external light irradiation, which stimulates an oxygen-independent, radical-mediated process that degrades the PLGA nanoparticles and releases the molecule. As these PLGA-encapsulated EtNBS nanoparticles are capable of penetrating deeply into the hypoxic and acidic cores of 3D spheroid cultures, they may enable the safe and efficacious treatment of otherwise unresponsive tumour regions.

  17. Nanobody conjugated PLGA nanoparticles for active targeting of African Trypanosomiasis.

    PubMed

    Arias, José L; Unciti-Broceta, Juan D; Maceira, José; Del Castillo, Teresa; Hernández-Quero, José; Magez, Stefan; Soriano, Miguel; García-Salcedo, José A

    2015-01-10

    Targeted delivery of therapeutics is an alternative approach for the selective treatment of infectious diseases. The surface of African trypanosomes, the causative agents of African trypanosomiasis, is covered by a surface coat consisting of a single variant surface glycoprotein, termed VSG. This coat is recycled by endocytosis at a very high speed, making the trypanosome surface an excellent target for the delivery of trypanocidal drugs. Here, we report the design of a drug nanocarrier based on poly ethylen glycol (PEG) covalently attached (PEGylated) to poly(D,L-lactide-co-glycolide acid) (PLGA) to generate PEGylated PLGA nanoparticles. This nanocarrier was coupled to a single domain heavy chain antibody fragment (nanobody) that specifically recognizes the surface of the protozoan pathogen Trypanosoma brucei. Nanoparticles were loaded with pentamidine, the first-line drug for T. b. gambiense acute infection. An in vitro effectiveness assay showed a 7-fold decrease in the half-inhibitory concentration (IC50) of the formulation relative to free drug. Furthermore, in vivo therapy using a murine model of African trypanosomiasis demonstrated that the formulation cured all infected mice at a 10-fold lower dose than the minimal full curative dose of free pentamidine and 60% of mice at a 100-fold lower dose. This nanocarrier has been designed with components approved for use in humans and loaded with a drug that is currently in use to treat the disease. Moreover, this flexible nanobody-based system can be adapted to load any compound, opening a range of new potential therapies with application to other diseases.

  18. Thermogelling Biodegradable Polymers with Hydrophilic Backbones: PEG-g-PLGA

    SciTech Connect

    Jeong, Byeongmoon; Kibbey, Merinda R.; Birnbaum, Jerome C.; Won, You-Yeong; Gutowska, Anna

    2000-10-31

    The aqueous solutions of poly(ethylene glycol)grafted with poly(lactic acid-co-glycolic acid) flow freely at room temperature but form gels at higher temperature. The existence of micelles in water at low polymer concentration was confirmed by Cro-transmission electron microscopy and dye solubilization studies. The micellar diameter and critical micelle concentration are about 9 nm and 0.47 wt.% respectively. The critical gel concentration, above which a gel phase appears was 16 wt.% and sol-to-gel transition temperature was slightly affected by the concentration in the range of 16 {approx} 25 wt.%. At sol-to-gel transition, viscosity increased abruptly and C-NMR showed molecular motion of hydrophilic poly(lactic acid-co-glycolic acid) side-chains increased. The hydrogel of PEG-g-PLGA with hydrophilic backbones was transparent during degradation and remained a gel for one week, suggesting a promising material for short-term drug delivery.

  19. Improving bone repair of femoral and radial defects in rabbit by incorporating PRP into PLGA/CPC composite scaffold with unidirectional pore structure.

    PubMed

    He, Fupo; Chen, Yan; Li, Jiyan; Lin, Bomiao; Ouyang, Yi; Yu, Bo; Xia, Yuanyou; Yu, Bo; Ye, Jiandong

    2015-04-01

    In this study, a platelet-rich plasma poly(lactic-co-glycolic acid) (PRP-PLGA)/calcium phosphate cement (CPC) composite scaffold was prepared by incorporating PRP into PLGA/CPC scaffold with unidirectional pore structure, which was fabricated by the unidirectional freeze casting of CPC slurry and the following infiltration of PLGA. The results from in vitro cell experiments and in vivo implantation in femoral defects manifested that incorporation of PRP into PLGA/CPC scaffold improved in vitro cell response (cell attachment, proliferation, and differentiation), and markedly boosted bone formation, angiogenesis and material degradation. The incorporation of PRP into scaffold showed more outstanding improvement in osteogenesis as the scaffolds were used to repair the segmental radial defects, especially at the early stage. The new bone tissues grew along the unidirectional lamellar pores of scaffold. At 12 weeks postimplantation, the segmental radial defects treated with PRP-PLGA/CPC scaffold had almost recuperated, whereas treated with the scaffold without PRP was far from healed. Taken together, the PRP-PLGA/CPC scaffold with unidirectional pore structure is a promising candidate to repair bone defects at various sites.

  20. Multifunctional SPIO/DOX-loaded A54 Homing Peptide Functionalized Dextran-g-PLGA Micelles for Tumor Therapy and MR Imaging

    NASA Astrophysics Data System (ADS)

    Situ, Jun-Qing; Wang, Xiao-Juan; Zhu, Xiu-Liang; Xu, Xiao-Ling; Kang, Xu-Qi; Hu, Jing-Bo; Lu, Chen-Ying; Ying, Xiao-Ying; Yu, Ri-Sheng; You, Jian; Du, Yong-Zhong

    2016-10-01

    Specific delivery of chemotherapy drugs and magnetic resonance imaging (MRI) contrast agent into tumor cells is one of the issues to highly efficient tumor targeting therapy and magnetic resonance imaging. Here, A54 peptide-functionalized poly(lactic-co-glycolic acid)-grafted dextran (A54-Dex-PLGA) was synthesized. The synthesized A54-Dex-PLGA could self-assemble to form micelles with a low critical micelle concentration of 22.51 μg. mL‑1 and diameter of about 50 nm. The synthetic A54-Dex-PLGA micelles can encapsulate doxorubicin (DOX) as a model anti-tumor drug and superparamagnetic iron oxide (SPIO) as a contrast agent for MRI. The drug-encapsulation efficiency was about 80% and the in vitro DOX release was prolonged to 72 hours. The DOX/SPIO-loaded micelles could specifically target BEL-7402 cell line. In vitro MRI results also proved the specific binding ability of A54-Dex-PLGA/DOX/SPIO micelles to hepatoma cell BEL-7402. The in vivo MR imaging experiments using a BEL-7402 orthotopic implantation model further validated the targeting effect of DOX/SPIO-loaded micelles. In vitro and in vivo anti-tumor activities results showed that A54-Dex-PLGA/DOX/SPIO micelles revealed better therapeutic effects compared with Dex-PLGA/DOX/SPIO micelles and reduced toxicity compared with commercial adriamycin injection.

  1. Multifunctional SPIO/DOX-loaded A54 Homing Peptide Functionalized Dextran-g-PLGA Micelles for Tumor Therapy and MR Imaging

    PubMed Central

    Situ, Jun-Qing; Wang, Xiao-Juan; Zhu, Xiu-Liang; Xu, Xiao-Ling; Kang, Xu-Qi; Hu, Jing-Bo; Lu, Chen-Ying; Ying, Xiao-Ying; Yu, Ri-Sheng; You, Jian; Du, Yong-Zhong

    2016-01-01

    Specific delivery of chemotherapy drugs and magnetic resonance imaging (MRI) contrast agent into tumor cells is one of the issues to highly efficient tumor targeting therapy and magnetic resonance imaging. Here, A54 peptide-functionalized poly(lactic-co-glycolic acid)-grafted dextran (A54-Dex-PLGA) was synthesized. The synthesized A54-Dex-PLGA could self-assemble to form micelles with a low critical micelle concentration of 22.51 μg. mL−1 and diameter of about 50 nm. The synthetic A54-Dex-PLGA micelles can encapsulate doxorubicin (DOX) as a model anti-tumor drug and superparamagnetic iron oxide (SPIO) as a contrast agent for MRI. The drug-encapsulation efficiency was about 80% and the in vitro DOX release was prolonged to 72 hours. The DOX/SPIO-loaded micelles could specifically target BEL-7402 cell line. In vitro MRI results also proved the specific binding ability of A54-Dex-PLGA/DOX/SPIO micelles to hepatoma cell BEL-7402. The in vivo MR imaging experiments using a BEL-7402 orthotopic implantation model further validated the targeting effect of DOX/SPIO-loaded micelles. In vitro and in vivo anti-tumor activities results showed that A54-Dex-PLGA/DOX/SPIO micelles revealed better therapeutic effects compared with Dex-PLGA/DOX/SPIO micelles and reduced toxicity compared with commercial adriamycin injection. PMID:27775017

  2. Modified poly(lactic-co-glycolic acid) nanoparticles for enhanced cellular uptake and gene editing in the lung.

    PubMed

    Fields, Rachel J; Quijano, Elias; McNeer, Nicole Ali; Caputo, Christina; Bahal, Raman; Anandalingam, Kavi; Egan, Marie E; Glazer, Peter M; Saltzman, W Mark

    2015-02-18

    Surface-modified poly(lactic-co-glycolic acid) (PLGA)/poly(β-aminoester)(PBAE)nanoparticles (NPs) have shown great promise in gene delivery. In this work, the pulmonary cellular uptake of these NPs is evaluated and surface-modified PLGA/PBAE NPs are shown to achieve higher cellular association and gene editing than traditional NPs composed of PLGA or PLGA/PBAE blends alone.

  3. Enhanced singlet oxygen generation from PLGA loaded with verteporfin and gold nanoparticles

    NASA Astrophysics Data System (ADS)

    Deng, Wei; Kautzka, Zofia; Goldys, Ewa M.

    2016-12-01

    In this study, poly(lactic-co-glycolic acid) (PLGA) nanocomposites were developed by incorporating a photosensitizer, verteporfin and gold nanoparticles into this polymeric matrix and utilised for enhanced photoynamic therapy. Both enhanced fluorescence and singlet oxygen generation from verteporfin were observed in this new formulation under both 425nm LED and 405nm laser illumination. A maximum enhancement factor of 2.5 for fluorescence and 1.84 for 1O2 generation was obtained when the molar ratio of gold:VP was 5:1 and excited at 425 nm, compared with PLGA doped with verteporfin only. The experiment results could be explained by the local electric field enhancement of gold nanoparticles. Furthermore, in vitro cell-killing effect on human pancreatic cancer cells was also demonstrated by using this new formulation following light exposure, indicating the utility of these nanocomposites for enhanced photodynamic therapy.

  4. PLGA-loaded nanomedicines in melanoma treatment: Future prospect for efficient drug delivery

    PubMed Central

    Das, Sreemanti; Khuda-Bukhsh, Anisur Rahman

    2016-01-01

    Current treatment methods for melanoma have some limitations such as less target-specific action, severe side effects and resistance to drugs. Significant progress has been made in exploring novel drug delivery systems based on suitable biochemical mechanisms using nanoparticles ranging from 10 to 400 nm for drug delivery and imaging, utilizing their enhanced penetration and retention properties. Poly-lactide-co-glycolide (PLGA), a copolymer of poly-lactic acid and poly-glycolic acid, provides an ideally suited performance-based design for better penetration into skin cells, thereby having a greater potential for the treatment of melanoma. Moreover, encapsulation protects the drug from deactivation by biological reactions and interactions with biomolecules, ensuring successful delivery and bioavailability for effective treatment. Controlled and sustained delivery of drugs across the skin barrier that otherwise prohibits entry of larger molecules can be successfully made with adequately stable biocompatible nanocarriers such as PLGA for taking drugs through the small cutaneous pores permitting targeted deposition and prolonged drug action. PLGA is now being extensively used in photodynamic therapy and targeted therapy through modulation of signal proteins and drug-DNA interactions. Recent advances made on these nanomedicines and their advantages in the treatment of skin melanoma are highlighted and discussed in this review. PMID:27934796

  5. Prediction of dexamethasone release from PLGA microspheres prepared with polymer blends using a design of experiment approach.

    PubMed

    Gu, Bing; Burgess, Diane J

    2015-11-10

    Hydrophobic drug release from poly (lactic-co-glycolic acid) (PLGA) microspheres typically exhibits a tri-phasic profile with a burst release phase followed by a lag phase and a secondary release phase. High burst release can be associated with adverse effects and the efficacy of the formulation cannot be ensured during a long lag phase. Accordingly, the development of a long-acting microsphere product requires optimization of all drug release phases. The purpose of the current study was to investigate whether a blend of low and high molecular weight polymers can be used to reduce the burst release and eliminate/minimize the lag phase. A single emulsion solvent evaporation method was used to prepare microspheres using blends of two PLGA polymers (PLGA5050 (25 kDa) and PLGA9010 (113 kDa)). A central composite design approach was applied to investigate the effect of formulation composition on dexamethasone release from these microspheres. Mathematical models obtained from this design of experiments study were utilized to generate a design space with maximized microsphere drug loading and reduced burst release. Specifically, a drug loading close to 15% can be achieved and a burst release less than 10% when a composition of 80% PLGA9010 and 90 mg of dexamethasone is used. In order to better describe the lag phase, a heat map was generated based on dexamethasone release from the PLGA microsphere/PVA hydrogel composite coatings. Using the heat map an optimized formulation with minimum lag phase was selected. The microspheres were also characterized for particle size/size distribution, thermal properties and morphology. The particle size was demonstrated to be related to the polymer concentration and the ratio of the two polymers but not to the dexamethasone concentration.

  6. Ultrasound-stimulated peripheral nerve regeneration within asymmetrically porous PLGA/Pluronic F127 nerve guide conduit.

    PubMed

    Park, Sang Chul; Oh, Se Heang; Seo, Tae Beom; Namgung, Uk; Kim, Jin Man; Lee, Jin Ho

    2010-08-01

    Recently, we developed a novel method to fabricate a nerve guide conduit (NGC) with asymmetrical pore structure and hydrophilicity using poly(lactic-co-glycolic acid) (PLGA) and Pluronic F127 by a modified immersion precipitation method. From the animal study using a rat model (sciatic nerve defect of rat), we recognized that the unique PLGA/Pluronic F127 tube provided good environments for nerve regeneration. In this study, we applied low-intensity pulsed ultrasound as a simple and noninvasive stimulus at the PLGA/F127 NGC-implanted site transcutaneously in rats to investigate the feasibility of ultrasound for the enhanced nerve regeneration through the tube. The nerve regeneration behaviors within the ultrasound-stimulated PLGA/Pluronic F127 NGCs were compared with the NGCs without the ultrasound treatment as well as normal nerve by histological and immunohistochemical observations. It was observed that the PLGA/Pluronic F127 tube-implanted group applied with the ultrasound had more rapid nerve regeneration behavior (approximately 0.71 mm/day) than the tube-implanted group without the ultrasound treatment (approximately 0.48 mm/day). The ultrasound-treated tube group also showed greater neural tissue area as well as larger axon diameter and thicker myelin sheath than the tube group without the ultrasound treatment, indicating better nerve regeneration. The better nerve regeneration behavior in the our NGC/ultrasound system may be caused by the synergistic effect of the asymmetrically porous PLGA/Pluronic F127 tube with unique properties (selective permeability, hydrophilicity, and structural stability, which can provide good environment for nerve regeneration) and physical stimulus (stimulation of the Schwann cells and activation of the neurotrophic factors).

  7. Graphene oxide-stimulated myogenic differentiation of C2C12 cells on PLGA/RGD peptide nanofiber matrices

    NASA Astrophysics Data System (ADS)

    Shin, Y. C.; Lee, J. H.; Kim, M. J.; Hong, S. W.; Oh, J.-W.; Kim, C.-S.; Kim, B.; Hyun, J. K.; Kim, Y.-J.; Han, D.-W.

    2015-07-01

    During the last decade, much attention has been paid to graphene-based nanomaterials because they are considered as potential candidates for biomedical applications such as scaffolds for tissue engineering and substrates for the differentiation of stem cells. Until now, electrospun matrices composed of various biodegradable copolymers have been extensively developed for tissue engineering and regeneration; however, their use in combination with graphene oxide (GO) is novel and challenging. In this study, nanofiber matrices composed of poly(lactic-co-glycolic acid, PLGA) and M13 phage with RGD peptide displayed on its surface (RGD peptide-M13 phage) were prepared as extracellular matrix (ECM)-mimicking substrates. RGD peptide is a tripeptide (Arg-Gly-Asp) found on ECM proteins that promotes various cellular behaviors. The physicochemical properties of PLGA and RGD peptide-M13 phage (PLGA/RGD peptide) nanofiber matrices were characterized by atomic force microscopy, Fourier-transform infrared spectroscopy and thermogravimetric analysis. In addition, the growth of C2C12 mouse myoblasts on the PLGA/RGD peptide matrices was examined by measuring the metabolic activity. Moreover, the differentiation of C2C12 mouse myoblasts on the matrices when treated with GO was evaluated. The cellular behaviors, including growth and differentiation of C2C12 mouse myoblasts, were substantially enhanced on the PLGA/RGD peptide nanofiber matrices when treated with GO. Overall, these findings suggest that the PLGA/RGD peptide nanofiber matrices can be used in combination with GO as a novel strategy for skeletal tissue regeneration.

  8. Comparison of three different methods for effective introduction of platelet-rich plasma on PLGA woven mesh.

    PubMed

    Lee, Ji-Hye; Nam, Jinwoo; Kim, Hee Joong; Yoo, Jeong Joon

    2015-03-11

    For successful tissue regeneration, effective cell delivery to defect site is very important. Various types of polymer biomaterials have been developed and applied for effective cell delivery. PLGA (poly lactic-co-glycolic acid), a synthetic polymer, is a commercially available and FDA approved material. Platelet-rich plasma (PRP) is an autologous growth factor cocktail containing various growth factors including PDGF, TGFβ-1 and BMPs, and has shown positive effects on cell behaviors. We hypothesized that PRP pretreatment on PLGA mesh using different methods would cause different patterns of platelet adhesion and stages which would modulate cell adhesion and proliferation on the PLGA mesh. In this study, we pretreated PRP on PLGA using three different methods including simple dripping (SD), dynamic oscillation (DO) and centrifugation (CE), then observed the amount of adhered platelets and their activation stage distribution. The highest amount of platelets was observed on CE mesh and calcium treated CE mesh. Moreover, calcium addition after PRP coating triggered dramatic activation of platelets which showed large and flat morphologies of platelets with rich fibrin networks. Human chondrocytes (hCs) and human bone marrow stromal cells (hBMSCs) were next cultured on PRP-pretreated PLGA meshes using different preparation methods. CE mesh showed a significant increase in the initial cell adhesion of hCs and proliferation of hBMSCs compared with SD and DO meshes. The results demonstrated that the centrifugation method can be considered as a promising coating method to introduce PRP on PLGA polymeric material which could improve cell-material interaction using a simple method.

  9. Sustained delivery of rhBMP-2 via PLGA microspheres: cranial bone regeneration without heterotopic ossification or craniosynostosis

    PubMed Central

    Wink, Jason D.; Gerety, Patrick A.; Sherif, Rami D.; Lim, Youngshin; A.Clarke, Nadya; Rajapakse, Chamith S.; Nah, Hyun-Duck; Taylor, Jesse A.

    2014-01-01

    Background Commercially available recombinant human bone morphogenetic protein 2 (rhBMP2) has demonstrated efficacy in bone regeneration, but not without significant side effects. In this study, we utilize rhBMP2 encapsulated in PLGA microspheres (PLGA-rhBMP2) placed in a rabbit cranial defect model to test whether low-dose, sustained, delivery can effectively induce bone regeneration. Methods rhBMP2 was encapsulated in 15% poly (lactic-co-glycolic acid), using a double emulsion, solvent extraction/evaporation technique, and its release kinetics and bioactivity were tested. Two critical-size defects (10mm) were created in the calvarium of New Zealand White rabbits (5-7 mos of age, M/F) and filled with a collagen scaffold containing one of four groups: 1) no implant, 2) collagen scaffold only, 3) PLGA-rhBMP2(0.1ug/implant), or 4) free rhBMP2 (0.1ug/implant). After 6 weeks, the rabbits were sacrificed and defects were analyzed by μCT, histology, and finite element analysis. Results RhBMP2 delivered via bioactive PLGA microspheres resulted in higher volumes and surface area coverage of new bone than an equal dose of free rhBMP2 by μCT and histology (p=0.025, 0.025). FEA indicated that the mechanical competence using the regional elastic modulus did not differ with rhBMP2 exposure (p=0.70). PLGA-rhBMP2 did not demonstrate heterotopic ossification, craniosynostosis, or seroma formation. Conclusions Sustained delivery via PLGA microspheres can significantly reduce the rhBMP2 dose required for de novo bone formation. Optimization of the delivery system may be a key to reduce the risk for recently reported rhBMP2 related adverse effects. Level of Evidence Animal Study PMID:24622573

  10. Effects of designed PLLA and 50:50PLGA scaffold architectures on bone formation in vivo

    PubMed Central

    Saito, Eiji; Liao, Elly E.; Hu, Wei-Wen; Krebsbach, Paul H.; Hollister, Scott J.

    2015-01-01

    Biodegradable porous scaffolds have been investigated as an alternative approach to current metal, ceramic, and polymer bone graft substitutes for lost or damaged bone tissues. Although there have been many studies investigating the effects of scaffold architecture on bone formation, many of these scaffolds were fabricated using conventional methods, such as salt leaching and phase separation, and were constructed without designed architecture. To study the effects of both designed architecture and material on bone formation, we designed and fabricated three types of porous scaffold architecture from two biodegradable materials, poly (L-lactic acid) (PLLA) and 50:50Poly (lactic-co-glycolic acid) (PLGA) using image based design and indirect solid freeform fabrication techniques, seeded them with bone morphogenic protein-7 transduced human gingival fibroblasts and implanted them subcutaneously into mice for 4 and 8 weeks. Micro-computed tomography data confirmed that the fabricated porous scaffolds replicated the designed architectures. Histological analysis revealed that the 50:50PLGA scaffolds degraded and did not maintain their architecture after 4 weeks. The PLLA scaffolds maintained their architecture at both time points and showed improved bone ingrowth which followed the internal architecture of the scaffolds. Mechanical properties of both PLLA and 50:50PLGA scaffolds decreased, but PLLA scaffolds maintained greater mechanical properties than 50:50PLGA after implantation. The increase of mineralized tissue helped to support mechanical properties of bone tissue and scaffold constructs from 4 to 8 weeks. The results indicated the importance of choice of scaffold materials and computationally designed scaffolds to control tissue formation and mechanical properties for desired bone tissue regeneration. PMID:22162220

  11. Proteomics of Microparticles with SILAC Quantification (PROMIS-Quan): A Novel Proteomic Method for Plasma Biomarker Quantification*

    PubMed Central

    Harel, Michal; Oren-Giladi, Pazit; Kaidar-Person, Orit; Shaked, Yuval; Geiger, Tamar

    2015-01-01

    Unbiased proteomic analysis of plasma samples holds the promise to reveal clinically invaluable disease biomarkers. However, the tremendous dynamic range of the plasma proteome has so far hampered the identification of such low abundant markers. To overcome this challenge we analyzed the plasma microparticle proteome, and reached an unprecedented depth of over 3000 plasma proteins in single runs. To add a quantitative dimension, we developed PROMIS-Quan—PROteomics of MIcroparticles with Super-Stable Isotope Labeling with Amino Acids in Cell Culture (SILAC) Quantification, a novel mass spectrometry-based technology for plasma microparticle proteome quantification. PROMIS-Quan enables a two-step relative and absolute SILAC quantification. First, plasma microparticle proteomes are quantified relative to a super-SILAC mix composed of cell lines from distinct origins. Next, the absolute amounts of selected proteins of interest are quantified relative to the super-SILAC mix. We applied PROMIS-Quan to prostate cancer and compared plasma microparticle samples of healthy individuals and prostate cancer patients. We identified in total 5374 plasma-microparticle proteins, and revealed a predictive signature of three proteins that were elevated in the patient-derived plasma microparticles. Finally, PROMIS-Quan enabled determination of the absolute quantitative changes in prostate specific antigen (PSA) upon treatment. We propose PROMIS-Quan as an innovative platform for biomarker discovery, validation, and quantification in both the biomedical research and in the clinical worlds. PMID:25624350

  12. Capture and Direct Amplification of DNA on Chitosan Microparticles in a Single PCR-Optimal Solution.

    PubMed

    Pandit, Kunal R; Nanayakkara, Imaly A; Cao, Weidong; Raghavan, Srinivasa R; White, Ian M

    2015-11-03

    While nucleic acid amplification tests have great potential as tools for rapid diagnostics, complicated sample preparation requirements inhibit their use in near-patient diagnostics and low-resource-setting applications. Recent advancements in nucleic acid purification have leveraged pH-modulated charge switching polymers to reduce the number of steps required for sample preparation. The polycation chitosan (pKa 6.4) has been used to efficiently purify DNA by binding nucleic acids in acidic buffers and then eluting them at a pH higher than 8.0. Though it is an improvement over conventional methods, this multistep procedure has not transformed the application of nucleic acid amplification assays. Here we describe a simpler approach using magnetic chitosan microparticles that interact with DNA in a manner that has not been reported before. The microparticles capture DNA at a pH optimal for PCR (8.5) just as efficiently as at low pH. Importantly, the captured DNA is still accessible by polymerase, enabling direct amplification from the microparticles. We demonstrate quantitative PCR from DNA captured on the microparticles, thus eliminating nearly all of the sample preparation steps. We anticipate that this new streamlined method for preparing DNA for amplification will greatly expand the diagnostic applications of nucleic acid amplification tests.

  13. Hydrogel microparticles for biosensing

    PubMed Central

    Le Goff, Gaelle C.; Srinivas, Rathi L.; Hill, W. Adam; Doyle, Patrick S.

    2015-01-01

    Due to their hydrophilic, biocompatible, and highly tunable nature, hydrogel materials have attracted strong interest in the recent years for numerous biotechnological applications. In particular, their solution-like environment and non-fouling nature in complex biological samples render hydrogels as ideal substrates for biosensing applications. Hydrogel coatings, and later, gel dot surface microarrays, were successfully used in sensitive nucleic acid assays and immunoassays. More recently, new microfabrication techniques for synthesizing encoded particles from hydrogel materials have enabled the development of hydrogel-based suspension arrays. Lithography processes and droplet-based microfluidic techniques enable generation of libraries of particles with unique spectral or graphical codes, for multiplexed sensing in biological samples. In this review, we discuss the key questions arising when designing hydrogel particles dedicated to biosensing. How can the hydrogel material be engineered in order to tune its properties and immobilize bioprobes inside? What are the strategies to fabricate and encode gel particles, and how can particles be processed and decoded after the assay? Finally, we review the bioassays reported so far in the literature that have used hydrogel particle arrays and give an outlook of further developments of the field. PMID:26594056

  14. Novel PLGA-based nanoparticles for the oral delivery of insulin

    PubMed Central

    Malathi, Sampath; Nandhakumar, Perumal; Pandiyan, Velayudham; Webster, Thomas J; Balasubramanian, Sengottuvelan

    2015-01-01

    Background Insulin is the drug therapy for patients with insulin-dependent diabetes mellitus. A number of attempts have been made in the past to overcome the problems associated with the oral delivery of insulin, but with little success. Orally administered insulin has encountered with many difficulties such as rapid degradation and poor intestinal absorption. The potential use of D-α-tocopherol poly(ethylene glycol) 1000 succinate (TPGS)-emulsified poly(ethylene glycol) (PEG)-capped poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NPs) was investigated for sustained delivery of insulin (IS). Objective To investigate the efficacy of TPGS-emulsified PEG-capped PLGA NPs (TPPLG NPs) as a potential drug carrier for the oral delivery of insulin. Methods A series of biodegradable low-molecular-weight PLGA (80/20 [PLG4] and 70/30 [PLG6]) copolymers were synthesized by melt polycondensation. The commercial insulin-loaded TPGS-emulsified PEG-capped PLGA NPs (ISTPPLG NPs) were synthesized by water–oil–water emulsion solvent evaporation method. The physical and chemical properties of PLGA copolymers, particle size, zeta potential, and morphology of the NPs were examined. The in vivo studies of ISTPPLG NPs were carried out in diabetic rats by oral administration. Results The maximum encapsulation efficiency of ISTPPLG6 NPs was 78.6%±1.2%, and the mean diameter of the NPs was 180±20 nm. The serum glucose level was significantly (twofold) decreased on treatment with ISTPPLG NPs, and there was a threefold decrease with insulin-loaded PLGA (70/30) NPs when compared to that of free insulin-treated diabetic rats. The results show that the oral administration of ISTPPLG6 NPs is an effective method of reducing serum glucose level for a period of 24 hours. Histopathological studies reveal that ISTPPLG NPs could restore the damage caused by streptozotocin in the liver, kidneys, and pancreas, indicating its biocompatibility and regenerative effects. Conclusion ISTPPLG6 NPs can

  15. Microparticles prepared from sulfenamide-based polymers

    PubMed Central

    D’Mello, Sheetal R.; Yoo, Jun; Bowden, Ned B.; Salem, Aliasger K.

    2015-01-01

    Polysulfenamides (PSN), with a SN linkage (RSNR2) along the polymer backbone, are a new class of biodegradable and biocompatible polymers. These polymers were unknown prior to 2012 when their synthesis and medicinally relevant properties were reported. The aim of this study was to develop microparticles as a controlled drug delivery system using polysulfenamide as the matrix material. The microparticles were prepared by a water-in-oil-in-water double emulsion solvent evaporation method. For producing drug-loaded particles, FITC-dextran was used as a model hydrophilic compound. At the optimal formulation conditions, the external morphology of the PSN microparticles was examined by scanning electron microscopy to show the formation of smooth-surfaced spherical particles with low polydispersity. The microparticles had a net negative surface charge (−23 mV) as analyzed by the zetasizer. The drug encapsulation efficiency of the particles and the drug loading were found to be dependent on the drug molecular weight, amount of FITC-dextran used in fabricating FITC-dextran loaded microparticles, concentration of PSN and surfactant, and volume of the internal and external water phases. FITC-dextran was found to be distributed throughout the PSN microparticles and was released in an initial burst followed by more continuous release over time. Confocal laser scanning microscopy was used to qualitatively observe the cellular uptake of PSN microparticles and indicated localization of the particles in both the cytoplasm and the nucleus. PMID:23862723

  16. Understanding reflection behavior as a key for interpreting complex signals in FBRM monitoring of microparticle preparation processes.

    PubMed

    Vay, Kerstin; Friess, Wolfgang; Scheler, Stefan

    2012-11-01

    The application of focused beam reflectance measurement (FBRM) was studied in a larger scale PLGA microparticle preparation process for monitoring changes of the particle size and the particles' surface properties. Further understanding how these parameters determine the chord length distribution (CLD) was gained by means of single object measurements and data of monodisperse microparticles. It was evaluated how the FBRM signal is influenced by the surface characteristics of the tested materials and the measuring conditions. Particles with good scattering properties provided comparable values for the CLD and the particle size distribution. Translucent particles caused an overestimation of the particle size by FBRM, whereas the values for transparent emulsion droplets were too low. Despite a strong dependence of FBRM results on the optical properties of the samples, it is a beneficial technique for online monitoring of microparticle preparation processes. The study demonstrated how changing reflection properties can be used to monitor structural changes during the solidification of emulsion droplets and to detect process instabilities by FBRM.

  17. Nitric oxide scavenging by red cell microparticles.

    PubMed

    Liu, Chen; Zhao, Weixin; Christ, George J; Gladwin, Mark T; Kim-Shapiro, Daniel B

    2013-12-01

    Red cell microparticles form during the storage of red blood cells and in diseases associated with red cell breakdown and asplenia, including hemolytic anemias such as sickle cell disease. These small phospholipid vesicles that are derived from red blood cells have been implicated in the pathogenesis of transfusion of aged stored blood and hemolytic diseases, via activation of the hemostatic system and effects on nitric oxide (NO) bioavailability. Red cell microparticles react with the important signaling molecule NO almost as fast as cell-free hemoglobin, about 1000 times faster than red-cell-encapsulated hemoglobin. The degree to which this fast reaction with NO by red cell microparticles influences NO bioavailability depends on several factors that are explored here. In the context of stored blood preserved in ADSOL, we find that both cell-free hemoglobin and red cell microparticles increase as a function of duration of storage, and the proportion of extra erythrocytic hemoglobin in the red cell microparticle fraction is about 20% throughout storage. Normalized by hemoglobin concentration, the NO-scavenging ability of cell-free hemoglobin is slightly higher than that of red cell microparticles as determined by a chemiluminescence NO-scavenging assay. Computational simulations show that the degree to which red cell microparticles scavenge NO will depend substantially on whether they enter the cell-free zone next to the endothelial cells. Single-microvessel myography experiments performed under laminar flow conditions demonstrate that microparticles significantly enter the cell-free zone and inhibit acetylcholine, endothelial-dependent, and NO-dependent vasodilation. Taken together, these data suggest that as little as 5 μM hemoglobin in red cell microparticles, an amount formed after the infusion of one unit of aged stored packed red blood cells, has the potential to reduce NO bioavailability and impair endothelial-dependent vasodilation.

  18. Three steps to breaking immune tolerance to lymphoma: a microparticle approach.

    PubMed

    Makkouk, Amani; Joshi, Vijaya B; Lemke, Caitlin D; Wongrakpanich, Amaraporn; Olivier, Alicia K; Blackwell, Sue E; Salem, Aliasger K; Weiner, George J

    2015-04-01

    In situ immunization aims at generating antitumor immune responses through manipulating the tumor microenvironment. On the basis of recent advances in the understanding of antitumor immunity, we designed a three-step approach to in situ immunization to lymphoma: (i) inducing immunogenic tumor cell death with the chemotherapeutic drug doxorubicin. Doxorubicin enhances the expression of "eat-me" signals by dying tumor cells, facilitating their phagocytosis by dendritic cells (DC). Because of the vesicant activity of doxorubicin, microparticles made of biodegradable polymer poly(lactide-co-glycolide) or PLGA can safely deliver doxorubicin intratumorally and are effective vaccine adjuvants, (ii) enhancing T-cell activation using anti-OX40 and (iii) sustaining T-cell responses by checkpoint blockade using anti-CTLA-4. In vitro, doxorubicin microparticles were less cytotoxic to DCs than to B lymphoma cells, did not require internalization by tumor cells, and significantly enhanced phagocytosis of tumor cells by DCs as compared with soluble doxorubicin. In mice, this three-step therapy induced CD4- and CD8-dependent systemic immune responses that enhanced T-cell infiltration into distant tumors, leading to their eradication and significantly improving survival. Our findings demonstrate that systemic antitumor immune responses can be generated locally by three-step therapy and merit further investigation as an immunotherapy for patients with lymphoma.

  19. A Biomimetic Approach to Active Self-Microencapsulation of Proteins in PLGA

    PubMed Central

    Shah, Ronak B.; Schwendeman, Steven P.

    2014-01-01

    A biomimetic approach to organic solvent-free microencapsulation of proteins based on the self-healing capacity of poly (DL)-lactic-co-glycolic acid (PLGA) microspheres containing glycosaminoglycan-like biopolymers (BPs), was examined. To screen BPs, aqueous solutions of BP [high molecular weight dextran sulfate (HDS), low molecular weight dextran sulfate (LDS), chondroitin sulfate (CS), heparin (HP), hyaluronic acid (HA), chitosan (CH)] and model protein lysozyme (LYZ) were combined in different molar and mass ratios, at 37 °C and pH 7. The BP-PLGA microspheres (20–63 µm) were prepared by a double water-oil-water emulsion method with a range of BP content, and trehalose and MgCO3 to control microclimate pH and to create percolating pores for protein. Biomimetic active self-encapsulation (ASE) of proteins [LYZ, vascular endothelial growth factor165 (VEGF) and fibroblast growth factor (FgF-20)] was accomplished by incubating blank BP-PLGA microspheres in low concentration protein solutions at ~24 °C, for 48 h. Pore closure was induced at 42.5 °C under mild agitation for 42 h. Formulation parameters of BP-PLGA microspheres and loading conditions were studied to optimize protein loading and subsequent release. LDS and HP were found to bind >95% LYZ at BP:LYZ >0.125 w/w, whereas HDS and CS bound > 80% LYZ at BP:LYZ of 0.25–1 and < 0.33, respectively. HA-PLGA microspheres were found to be not ideal for obtaining high protein loading (>2% w/w of LYZ). Sulfated BP-PLGA microspheres were capable of loading LYZ (~2–7 % w/w), VEGF (~ 4% w/w), and FgF-20 (~2% w/w) with high efficiency. Protein loading was found to be dependent on the loading solution concentration, with higher protein loading obtained at higher loading solution concentration within the range investigated. Loading also increased with content of sulfated BP in microspheres. Release kinetics of proteins was evaluated in-vitro with complete release media replacement. Rate and extent of release were

  20. A biomimetic approach to active self-microencapsulation of proteins in PLGA.

    PubMed

    Shah, Ronak B; Schwendeman, Steven P

    2014-12-28

    A biomimetic approach to organic solvent-free microencapsulation of proteins based on the self-healing capacity of poly (DL)-lactic-co-glycolic acid (PLGA) microspheres containing glycosaminoglycan-like biopolymers (BPs), was examined. To screen BPs, aqueous solutions of BP [high molecular weight dextran sulfate (HDS), low molecular weight dextran sulfate (LDS), chondroitin sulfate (CS), heparin (HP), hyaluronic acid (HA), chitosan (CH)] and model protein lysozyme (LYZ) were combined in different molar and mass ratios, at 37 °C and pH7. The BP-PLGA microspheres (20-63 μm) were prepared by a double water-oil-water emulsion method with a range of BP content, and trehalose and MgCO3 to control microclimate pH and to create percolating pores for protein. Biomimetic active self-encapsulation (ASE) of proteins [LYZ, vascular endothelial growth factor165 (VEGF) and fibroblast growth factor (FgF-20)] was accomplished by incubating blank BP-PLGA microspheres in low concentration protein solutions at ~24 °C, for 48 h. Pore closure was induced at 42.5 °C under mild agitation for 42h. Formulation parameters of BP-PLGA microspheres and loading conditions were studied to optimize protein loading and subsequent release. LDS and HP were found to bind >95% LYZ at BP:LYZ>0.125 w/w, whereas HDS and CS bound >80% LYZ at BP:LYZ of 0.25-1 and <0.33, respectively. HA-PLGA microspheres were found to be not ideal for obtaining high protein loading (>2% w/w of LYZ). Sulfated BP-PLGA microspheres were capable of loading LYZ (~2-7% w/w), VEGF (~4% w/w), and FgF-20 (~2% w/w) with high efficiency. Protein loading was found to be dependent on the loading solution concentration, with higher protein loading obtained at higher loading solution concentration within the range investigated. Loading also increased with content of sulfated BP in microspheres. Release kinetics of proteins was evaluated in-vitro with complete release media replacement. Rate and extent of release were found to depend

  1. Surface characteristics of PLA and PLGA films

    NASA Astrophysics Data System (ADS)

    Paragkumar N, Thanki; Edith, Dellacherie; Six, Jean-Luc

    2006-12-01

    Surface segregation and restructuring in polylactides (poly( D, L-lactide) and poly( L-lactide)) and poly( D,L-lactide-co-glycolide) (PLGA) films of various thicknesses were investigated using both attenuated total reflection FTIR (ATR-FTIR) and contact angle relaxation measurements. In case of poly( D,L-lactide) (DLPLA), it was observed that the surface segregation and the surface restructuring of methyl side groups are influenced by the polymer film thickness. This result has been confirmed by X-ray photoelectron spectroscopy (XPS). In the same way, PLGA thick films were also characterized by an extensive surface segregation of methyl side groups. Finally, surface restructuring was investigated by dynamic contact angle measurements and it was observed when film surface comes into contact with water. In parallel, we also found that poly( L-lactide) (PLLA) thin and clear films with thickness ˜15 μm undergo conformational changes on the surface upon solvent treatment with certain solvents. The solvent treated surface of PLLA becomes hazy and milky white and its hydrophobicity increases compared to untreated surface. FTIR spectroscopic analysis indicated that polymer chains at the surface undergo certain conformational changes upon solvent treatment. These changes are identified as the restricted motions of C-O-C segments and more intense and specific vibrations of methyl side groups. During solvent treatment, the change in water contact angle and FTIR spectrum of PLLA is well correlated.

  2. Encapsulation-free controlled release: Electrostatic adsorption eliminates the need for protein encapsulation in PLGA nanoparticles

    PubMed Central

    Pakulska, Malgosia M.; Elliott Donaghue, Irja; Obermeyer, Jaclyn M.; Tuladhar, Anup; McLaughlin, Christopher K.; Shendruk, Tyler N.; Shoichet, Molly S.

    2016-01-01

    Encapsulation of therapeutic molecules within polymer particles is a well-established method for achieving controlled release, yet challenges such as low loading, poor encapsulation efficiency, and loss of protein activity limit clinical translation. Despite this, the paradigm for the use of polymer particles in drug delivery has remained essentially unchanged for several decades. By taking advantage of the adsorption of protein therapeutics to poly(lactic-co-glycolic acid) (PLGA) nanoparticles, we demonstrate controlled release without encapsulation. In fact, we obtain identical, burst-free, extended-release profiles for three different protein therapeutics with and without encapsulation in PLGA nanoparticles embedded within a hydrogel. Using both positively and negatively charged proteins, we show that short-range electrostatic interactions between the proteins and the PLGA nanoparticles are the underlying mechanism for controlled release. Moreover, we demonstrate tunable release by modifying nanoparticle concentration, nanoparticle size, or environmental pH. These new insights obviate the need for encapsulation and offer promising, translatable strategies for a more effective delivery of therapeutic biomolecules. PMID:27386554

  3. Peripheral nerve regeneration within an asymmetrically porous PLGA/Pluronic F127 nerve guide conduit.

    PubMed

    Oh, Se Heang; Kim, Jun Ho; Song, Kyu Sang; Jeon, Byeong Hwa; Yoon, Jin Hwan; Seo, Tae Beom; Namgung, Uk; Lee, Il Woo; Lee, Jin Ho

    2008-04-01

    Asymmetrically porous tubes with selective permeability and hydrophilicity as nerve guide conduits (NGCs) were fabricated using poly(lactic-co-glycolic acid) (PLGA) and Pluronic F127 by a modified immersion precipitation method. The inner surface of the tube had nano-size pores ( approximately 50nm) which can effectively prevent from fibrous tissue infiltration but permeate nutrients and retain neurotrophic factors, while the outer surface had micro-size pores ( approximately 50microm) which can allow vascular ingrowth for effective supply of nutrients into the tube. From the animal study using a rat model, the hydrophilized PLGA/F127 (3wt%) tube showed better nerve regeneration behavior than the control silicone or hydrophobic PLGA tubes, as investigated by immunohistochemical observation (by fluorescent microscopy with anti-neurofilament staining), histological observations (by light microscopy with toluidine blue staining and transmission electron microscopy), and electrophysiological evaluation (by compound muscle action potential measurement). This is probably owing to the effective permeation of nutrients and prevention of fibrous scar tissue invasion as well as the good mechanical strength of the tube to maintain a stable support structure for the nerve regeneration.

  4. Collagen/silk fibroin composite scaffold incorporated with PLGA microsphere for cartilage repair.

    PubMed

    Wang, Jianhua; Yang, Qiu; Cheng, Niangmei; Tao, Xiaojun; Zhang, Zhihua; Sun, Xiaomin; Zhang, Qiqing

    2016-04-01

    For cartilage repair, ideal scaffolds should mimic natural extracellular matrix (ECM) exhibiting excellent characteristics, such as biocompatibility, suitable porosity, and good cell affinity. This study aimed to prepare a collagen/silk fibroin composite scaffold incorporated with poly-lactic-co-glycolic acid (PLGA) microsphere that can be applied in repairing cartilage. To obtain optimum conditions for manufacturing a composite scaffold, a scaffold composed of different collagen-to-silk fibroin ratios was evaluated by determining porosity, water absorption, loss rate in hot water, and cell proliferation. Results suggested that the optimal ratio of collagen and silk fibroin composite scaffold was 7:3. The microstructure and morphological characteristics of the obtained scaffold were also examined through scanning electron microscopy and Fourier transform infrared spectroscopy. The results of in vitro fluorescence staining of bone marrow stromal cells revealed that collagen/silk fibroin composite scaffold enhanced cell proliferation without eliciting side effects. The prepared composite scaffold incorporated with PLGA microsphere was implanted in fully thick articular cartilage defects in rabbits. Collagen/silk fibroin composite scaffold with PLGA microspheres could enhance articular cartilage regeneration and integration between the repaired cartilage and the surrounding cartilage. Therefore, this composite will be a promising material for cartilage repair and regeneration.

  5. In vitro and in vivo performance of dexamethasone loaded PLGA microspheres prepared using polymer blends.

    PubMed

    Gu, Bing; Wang, Yan; Burgess, Diane J

    2015-12-30

    The foreign body reaction is the major cause of the dysfunction and relatively short lifetime associated with implanted glucose biosensors. An effective strategy to maintain sensor functionality is to apply biocompatible coatings that elute drug to counter the negative tissue reactions. This has been achieved using dexamethasone releasing poly(lactic-co-glycolic acid) (PLGA) microspheres embedded in a polyvinyl alcohol (PVA) hydrogel coating. Accordingly, the biosensor lifetime relies on the duration and dose of drug release from the coating. To achieve long-term drug release mixed populations of microspheres have been used. In the current study, microspheres were prepared by blending low (25KDa) and high (113KDa) molecular weight PLGA at different mass ratios to overcome problems associated with mixing multiple populations of microspheres. "Real-time" in vitro studies demonstrated dexamethasone release for approximately 5 months. An accelerated method with discriminatory ability was developed to shorten drug release to less than 2 weeks. An in vivo pharmacodynamics study demonstrated efficacy against the foreign body reaction for 4.5 months. Such composite coatings composed of PLGA microspheres prepared using polymer blends could potentially be used to ensure long-term performance of glucose sensors.

  6. Biological activity of rhBMP-2 released from PLGA microspheres.

    PubMed

    Oldham, J B; Lu, L; Zhu, X; Porter, B D; Hefferan, T E; Larson, D R; Currier, B L; Mikos, A G; Yaszemski, M J

    2000-06-01

    Human recombinant bone morphogenetic protein-2 (rhBMP-2) has been proven effective in stimulating the regeneration of bone in both skeletal and extraskeletal locations. Through encapsulation within, and release from, biodegradable poly(DL-lactic-co-glycolic acid) (PLGA) microspheres, a proven vehicle for sustained delivery of various proteins, the local concentrations of rhBMP-2 could be maintained at optimal levels to stimulate bone regeneration and remodeling at the site of healing in diverse clinical settings. Thus the purpose of this work was to investigate the encapsulation of rhBMP-2 in PLGA microspheres and its biologic activity upon release. Using in vitro tests in simulated body fluids, the effect of rhBMP-2 released from PLGA microspheres upon osteoblast cell cultures was found to be statistically similar to the effect produced by positive controls consisting of nonencapsulated aqueous rhBMP-2 in simulated body fluids. This clarifies an important step in skeletal tissue engineering strategies aimed at the use of encapsulated rhBMP-2 to stimulate bone regeneration and remodeling.

  7. Electrospun PLGA/gelatin fibrous tubes for the application of biodegradable intestinal stent in rat model.

    PubMed

    Son, So-Ra; Franco, Rose-Ann; Bae, Sang-Ho; Min, Young-Ki; Lee, Byong-Taek

    2013-08-01

    A biodegradable fibrous tube was fabricated by electrospinning method using a combination of Poly(lactic-co-glycolic acid) (PLGA) and gelatin dissolved in trifluoroethanol (TFE). Different ratios of the two polymers (PLGA/Gelatin: 1/9, 3/7, 5/5) were used for electrospinning to determine the optimum condition appropriate for intestinal stent application. Fiber morphology was visualized and analyzed using a scanning electron microscope (SEM). Characterizations of physical properties were done according to its tensile strength, surface hydrophilicity, swelling ability, and biodegradability. Biocompatibility of the scaffolds was investigated in vitro using IEC-18 (Rat intestinal epithelial cell). Cell proliferation was quantified using MTT assay and cell adhesion behavior was visualized by SEM and confocal laser scanning microscope. PLGA/Gelatin (5/5) was determined to have adequate material properties and sufficient in vitro biocompatibility. This was then implanted in a male Sprague-Dawley rat for 14 days to determine in vivo behavior of the sample. Histological examination on the intestinal tissue surrounding the graft showed normal morphology comparable to non-implanted intestine.

  8. Gelsolin Amyloidogenesis Is Effectively Modulated by Curcumin and Emetine Conjugated PLGA Nanoparticles

    PubMed Central

    Goel, Surbhi; Kundu, Bishwajit; Mishra, Prashant; Fnu, Ashish

    2015-01-01

    Small molecule based therapeutic intervention of amyloids has been limited by their low solubility and poor pharmacokinetic characteristics. We report here, the use of water soluble poly lactic-co-glycolic acid (PLGA)-encapsulated curcumin and emetine nanoparticles (Cm-NPs and Em-NPs, respectively), as potential modulators of gelsolin amyloidogenesis. Using the amyloid-specific dye Thioflavin T (ThT) as an indicator along with electron microscopic imaging we show that the presence of Cm-NPs augmented amyloid formation in gelsolin by skipping the pre-fibrillar assemblies, while Em-NPs induced non-fibrillar aggregates. These two types of aggregates differed in their morphologies, surface hydrophobicity and secondary structural signatures, confirming that they followed distinct pathways. In spite of differences, both these aggregates displayed reduced toxicity against SH-SY5Y human neuroblastoma cells as compared to control gelsolin amyloids. We conclude that the cytotoxicity of gelsolin amyloids can be reduced by either stalling or accelerating its fibrillation process. In addition, Cm-NPs increased the fibrillar bulk while Em-NPs defibrillated the pre-formed gelsolin amyloids. Moreover, amyloid modulation happened at a much lower concentration and at a faster rate by the PLGA encapsulated compounds as compared to their free forms. Thus, besides improving pharmacokinetic and biocompatible properties of curcumin and emetine, PLGA conjugation elevates the therapeutic potential of both small molecules against amyloid fibrillation and toxicity. PMID:25996685

  9. Reconstructing jaw defects with MSCs and PLGA-encapsulated growth factors

    PubMed Central

    Tee, Boon Ching; Desai, Kashappa Goud H; Kennedy, Kelly S; Sonnichsen, Brittany; Kim, Do-Gyoon; Fields, Henry W; Mallery, Susan R; Schwendeman, Steven P; Sun, Zongyang

    2016-01-01

    Cell and growth factor-based tissue engineering has shown great potentials for skeletal regeneration. This study tested its feasibility in reconstructing large mandibular defects and compared the efficacy of varied construction materials and sealing methods. Bilateral mandibular critical-size (5-cm3) defects were created on six 4-month-old domestic pigs, and grafted with β-tricalcium phosphate (βTCP) only (Group-A), βTCP with autologous bone marrow-derived mesenchymal stem cells (BM-MSCs) (Group-B), and βTCP with BM-MSCs and biodegradable poly(lactic-co-glycolic acid) (PLGA) microspheres containing bone morphogenetic protein-2 (BMP-2) and vascular endothelial growth factor (VEGF) (Group-C). The buccal sides of Groups-B/-C were either sealed by fibrin sealant or by a biodegradable PLGA barrier membrane before soft-tissue closure. Computed tomography (CT), microCT and histology analyses were performed 12 weeks postoperatively. In vitro data demonstrated that BM-MSCs, with MSC properties confirmed, remained vital after integration with βTCP; and PLGA microspheres exhibited an initial burst followed by slow and continuous release of growth factors over a period of 28 days. In vivo data demonstrated that Group-B/-C sites had significantly greater gap obliteration, higher tissue mineral densities and more residual βTCP granules (p<0.05, Kruskal-Wallis tests). Qualitatively, Group-B/-C defect sites had started remodeling while Group-A sites were mainly forming new bone to bridge the gaps. Furthermore, βTCP degradation was not mediated by macrophages or osteoclasts, and was significantly slowed down by sealing the defects with barrier membrane. Combined, these data present a promising formulation composed of βTCP granules, autologous MSCs, controlled-release growth factors and biodegradable PLGA barrier membrane for the reconstruction of critical-size mandibular defects. PMID:27398152

  10. Studies on the preparation, characterization and pharmacological evaluation of tolterodine PLGA microspheres.

    PubMed

    Sun, Fengying; Sui, Cheng; Teng, Lesheng; Liu, Ximing; Teng, Lirong; Meng, Qingfan; Li, Youxin

    2010-09-15

    In this study, poly(d,l-lactide-co-glycolide) (PLGA) microspheres of tolterodine depot formulation were prepared using oil in water (o/w) method to investigate their potential pharmacokinetic and pharmacodynamic advantages over tolterodine l-tartrate tablets. Morphological studies of the microspheres showed a spherical shape and smooth surface with mean size of 50.69-83.01 microm, and the encapsulation efficiency was improved from 62.55 to 79.10% when the polymer concentration increased from 180 to 230 mg/ml. The addition of stearic or palmitic acids could significantly raise the drug entrapment efficiency but only slightly affected the in vitro release. A low initial burst followed by a proximately constant release of tolterodine was noticed in the in vitro release profiles. The in vivo study was carried out by intramuscular (i.m.) administration of tolterodine-loaded microspheres on beagle dogs, and a sustained release of drug from the PLGA microspheres was achieved until the 18th day with a low initial burst. Since the absence of hepatic first pass metabolism, only a single active compound-tolterodine was detected in the plasma. This avoided the coexistence of two active compounds in plasma in the case of oral administration of tolterodine, which may lead to a difficulty in dose control due to the different metabolic capacity of patients. In the pharmacodynamic study, the influence of tolterodine PLGA microspheres on the inhibition of carbachol-induced rat urinary bladder contraction was more significant than that of tolterodine l-tartrate tablets. There were invisible changes in rat bladder slices between tolterodine-loaded PLGA microspheres group and tolterodine l-tartrate tablets group. These results indicate that the continuous inhibition of muscarinic receptor may offer an alternative therapy of urge incontinence.

  11. Trojan Microparticles for Drug Delivery

    PubMed Central

    Anton, Nicolas; Jakhmola, Anshuman; Vandamme, Thierry F.

    2012-01-01

    During the last decade, the US Food and Drug Administration (FDA) have regulated a wide range of products, (foods, cosmetics, drugs, devices, veterinary, and tobacco) which may utilize micro and nanotechnology or contain nanomaterials. Nanotechnology allows scientists to create, explore, and manipulate materials in nano-regime. Such materials have chemical, physical, and biological properties that are quite different from their bulk counterparts. For pharmaceutical applications and in order to improve their administration (oral, pulmonary and dermal), the nanocarriers can be spread into microparticles. These supramolecular associations can also modulate the kinetic releases of drugs entrapped in the nanoparticles. Different strategies to produce these hybrid particles and to optimize the release kinetics of encapsulated drugs are discussed in this review. PMID:24300177

  12. Microparticles and type 2 diabetes.

    PubMed

    Leroyer, A S; Tedgui, A; Boulanger, C M

    2008-02-01

    Cell activation or apoptosis leads to plasma membrane blebbing and microparticles (MPs) release in the extracellular space. MPs are submicron membrane vesicles, which harbour a panel of oxidized phospholipids and proteins specific to the cells they derived from. MPs are found in the circulating blood of healthy volunteers. MPs levels are increased in many diseases, including cardiovascular diseases with high thrombotic risk. Exposure of negatively charged phospholipids and tissue factor confers a procoagulant potential to MPs. Elevation of plasma MPs levels, particularly those of endothelial origin, reflects cellular injury and appears now as a surrogate marker of vascular dysfunction. Recent studies demonstrate an elevation of circulating levels of MPs in diabetes. MPs could also be involved in the development of vascular complications in diabetes for they stimulate pro-inflammatory responses in target cells and promote thrombosis, endothelial dysfunction and angiogenesis. Thus, these studies provide new insight in the pathogenesis and treatment of vascular complications of diabetes.

  13. Development and in vitro characterization of insulin loaded whey protein and alginate microparticles.

    PubMed

    Déat-Lainé, Emmanuelle; Hoffart, Valérie; Cardot, Jean-Michel; Subirade, Muriel; Beyssac, Eric

    2012-12-15

    Insulin was encapsulated into microparticles (MP) made of denaturized whey proteins (WP) and alginate (ALG) using an extrusion/cold gelation process with calcium ions. High encapsulation efficiency of 85% was obtained. Influence of insulin on polymeric viscosity and on microparticle behavior was evaluated. Insulin seemed to interact with WP chains by non covalent binding and steric hindrance. This influence was balanced by ALG addition. Nevertheless, insulin was released rapidly by diffusion at both acidic and intestinal dissolution media. Despite this fast in vitro release, WP/ALG MP showed an important enzymatic inhibition effect on trypsin and alpha-chymotrypsin. Thus, WP/ALG MP contributed to an effective insulin protection towards enzymatic degradation. The aforementioned results suggested that WP based microparticles are a promising carrier for improving oral delivery of insulin.

  14. Design and characterization of a conductive nanostructured polypyrrole-polycaprolactone coated magnesium/PLGA composite for tissue engineering scaffolds.

    PubMed

    Liu, Haixia; Wang, Ran; Chu, Henry K; Sun, Dong

    2015-09-01

    A novel biodegradable and conductive composite consisting of magnesium (Mg), polypyrrole-block-ploycaprolactone (PPy-PCL), and poly(lactic-co-glycolic acid) (PLGA) is synthesized in a core-shell-skeleton manner for tissue engineering applications. Mg particles in the composite are first coated with a conductive nanostructured PPy-PCL layer for corrosion resistance via the UV-induced photopolymerization method. PLGA matrix is then added to tailor the biodegradability of the resultant composite. Composites with different composition ratios are examined through experiments, and their material properties are characterized. The in vitro experiments on culture of 293FT-GFP cells show that the composites are suitable for cell growth and culture. Biodegradability of the composite is also evaluated. By adding PLGA matrix to the composite, the degrading time of the composite can last for more than eight weeks, hence providing a longer period for tissue formation as compared to Mg composites or alloys. The findings of this research will offer a new opportunity to utilize a conductive, nanostructured-coated Mg/PLGA composite as the scaffold material for implants and tissue regeneration.

  15. Salidroside promotes peripheral nerve regeneration based on tissue engineering strategy using Schwann cells and PLGA: in vitro and in vivo

    PubMed Central

    Liu, Hui; Lv, Peizhen; Zhu, Yongjia; Wu, Huayu; Zhang, Kun; Xu, Fuben; Zheng, Li; Zhao, Jinmin

    2017-01-01

    Salidriside (SDS), a phenylpropanoid glycoside derived from Rhodiola rosea L, has been shown to be neuroprotective in many studies, which may be promising in nerve recovery. In this study, the neuroprotective effects of SDS on engineered nerve constructed by Schwann cells (SCs) and Poly (lactic-co-glycolic acid) (PLGA) were studied in vitro. We further investigated the effect of combinational therapy of SDS and PLGA/SCs based tissue engineering on peripheral nerve regeneration based on the rat model of nerve injury by sciatic transection. The results showed that SDS dramatically enhanced the proliferation and function of SCs. The underlying mechanism may be that SDS affects SCs growth through the modulation of neurotrophic factors (BDNF, GDNF and CNTF). 12 weeks after implantation with a 12 mm gap of sciatic nerve injury, SDS-PLGA/SCs achieved satisfying outcomes of nerve regeneration, as evidenced by morphological and functional improvements upon therapy by SDS, PLGA/SCs or direct suture group assessed by sciatic function index, nerve conduction assay, HE staining and immunohistochemical analysis. Our results demonstrated the significant role of introducing SDS into neural tissue engineering to promote nerve regeneration. PMID:28054637

  16. Interactions of PLGA nanoparticles with blood components: protein adsorption, coagulation, activation of the complement system and hemolysis studies.

    PubMed

    Fornaguera, Cristina; Calderó, Gabriela; Mitjans, Montserrat; Vinardell, Maria Pilar; Solans, Conxita; Vauthier, Christine

    2015-04-14

    The intravenous administration of poly(lactic-co-glycolic) acid (PLGA) nanoparticles has been widely reported as a promising alternative for delivery of drugs to specific cells. However, studies on their interaction with diverse blood components using different techniques are still lacking. Therefore, in the present work, the interaction of PLGA nanoparticles with blood components was described using different complementary techniques. The influence of different encapsulated compounds/functionalizing agents on these interactions was also reported. It is worth noting that all these techniques can be simply performed, without the need for highly sophisticated apparatus or skills. Moreover, their transference to industries and application of quality control could be easily performed. Serum albumin was adsorbed onto all types of tested nanoparticles. The saturation concentration was dependent on the nanoparticle size. In contrast, fibrinogen aggregation was dependent on nanoparticle surface charge. The complement activation was also influenced by the nanoparticle functionalization; the presence of a functionalizing agent increased complement activation, while the addition of an encapsulated compound only caused a slight increase. None of the nanoparticles influenced the coagulation cascade at low concentrations. However, at high concentrations, cationized nanoparticles did activate the coagulation cascade. Interactions of nanoparticles with erythrocytes did not reveal any hemolysis. Interactions of PLGA nanoparticles with blood proteins depended both on the nanoparticle properties and the protein studied. Independent of their loading/surface functionalization, PLGA nanoparticles did not influence the coagulation cascade and did not induce hemolysis of erythrocytes; they could be defined as safe concerning induction of embolization and cell lysis.

  17. Salidroside promotes peripheral nerve regeneration based on tissue engineering strategy using Schwann cells and PLGA: in vitro and in vivo

    NASA Astrophysics Data System (ADS)

    Liu, Hui; Lv, Peizhen; Zhu, Yongjia; Wu, Huayu; Zhang, Kun; Xu, Fuben; Zheng, Li; Zhao, Jinmin

    2017-01-01

    Salidriside (SDS), a phenylpropanoid glycoside derived from Rhodiola rosea L, has been shown to be neuroprotective in many studies, which may be promising in nerve recovery. In this study, the neuroprotective effects of SDS on engineered nerve constructed by Schwann cells (SCs) and Poly (lactic-co-glycolic acid) (PLGA) were studied in vitro. We further investigated the effect of combinational therapy of SDS and PLGA/SCs based tissue engineering on peripheral nerve regeneration based on the rat model of nerve injury by sciatic transection. The results showed that SDS dramatically enhanced the proliferation and function of SCs. The underlying mechanism may be that SDS affects SCs growth through the modulation of neurotrophic factors (BDNF, GDNF and CNTF). 12 weeks after implantation with a 12 mm gap of sciatic nerve injury, SDS-PLGA/SCs achieved satisfying outcomes of nerve regeneration, as evidenced by morphological and functional improvements upon therapy by SDS, PLGA/SCs or direct suture group assessed by sciatic function index, nerve conduction assay, HE staining and immunohistochemical analysis. Our results demonstrated the significant role of introducing SDS into neural tissue engineering to promote nerve regeneration.

  18. Magnetic hyperthermia efficiency and 1H-NMR relaxation properties of iron oxide/paclitaxel-loaded PLGA nanoparticles

    NASA Astrophysics Data System (ADS)

    Ruggiero, Maria R.; Geninatti Crich, Simonetta; Sieni, Elisabetta; Sgarbossa, Paolo; Forzan, Michele; Cavallari, Eleonora; Stefania, Rachele; Dughiero, Fabrizio; Aime, Silvio

    2016-07-01

    Magnetic iron oxide nanoparticles (Fe-NPs) can be exploited in biomedicine as agents for magnetic fluid hyperthermia (MFH) treatments and as contrast enhancers in magnetic resonance imaging. New, oleate-covered, iron oxide particles have been prepared either by co-precipitation or thermal decomposition methods and incorporated into poly(lactic-co-glycolic acid) nanoparticles (PLGA-Fe-NPs) to improve their biocompatibility and in vivo stability. Moreover, the PLGA-Fe-NPs have been loaded with paclitaxel to pursue an MFH-triggered drug release. Remarkably, it has been found that the nanoparticle formulations are characterized by peculiar 1H nuclear magnetic relaxation dispersion (NMRD) profiles that directly correlate with their heating potential when exposed to an alternating magnetic field. By prolonging the magnetic field exposure to 30 min, a significant drug release was observed for PLGA-Fe-NPs in the case of the larger-sized magnetic nanoparticles. Furthermore, the immobilization of lipophilic Fe-NPs in PLGA-NPs also made it possible to maintain Néel relaxation as the dominant relaxation contribution in the presence of large iron oxide cores (diameters of 15-20 nm), with the advantage of preserving their efficiency when they are entrapped in the intracellular environment. The results reported herein show that NMRD profiles are a useful tool for anticipating the heating capabilities of Fe-NPs designed for MFH applications.

  19. Efficacy of Ropinirole-Loaded PLGA Microspheres For The Reversion Of Rotenone-Induced Parkinsonism.

    PubMed

    Negro, Sofía; Boeva, Liudmilla; Slowing, Karla; Fernández-Carballido, Ana; García-García, Luis; Barcia, Emilia

    2016-09-28

    A new controlled delivery system is developed for ropinirole (RP) for the treatment of Parkinson´s disease (PD) consisting in PLGA microparticles (MPs) which exhibited in vitro constant release of RP (78.23 µg/day/10 mg MPs) for 19 days. The neuroprotective effects of RP released from MPs are evaluated in SKN-AS cells after exposure to rotenone (20 μM). Cell apoptosis was significantly reduced by RP (100-120 μM). Daily doses of rotenone (2 mg/kg) given i.p. to rats induced neuronal and behavioral changes similar to those of PD. After 15 days animals received RP in saline (1 mg/kg/day for 45 days) or as MPs at two dose levels (amount of MPs equivalent to 7.5 mg/kg or 15 mg/kg RP given on days 15 and 30). Brain immunochemistry (Nissl-staining, GFAP and TH immunohistochemistry) and behavioral testing (catalepsy, akinesia, rotarod and swim test) showed that animals receiving RP either in solution or encapsulated within MPs reverted PD symptoms with the best results obtained in animals receiving RP microspheres at the highest dose assayed, thereby confirming the potential therapeutic interest of the new RP delivery system.

  20. Enhanced secretory IgA and systemic IgG antibody responses after oral immunization with biodegradable microparticles containing antigen.

    PubMed Central

    Challacombe, S J; Rahman, D; Jeffery, H; Davis, S S; O'Hagan, D T

    1992-01-01

    Intragastric immunization may lead to the induction of antibodies in the secretory immune system including saliva. The antibody response is usually short-lived. The objectives of this study were to see whether oral immunization with biodegradable microparticles containing antigen might lead to enhanced mucosal responses. Ovalbumin (OVA) was entrapped in a novel antigen delivery system comprising poly (D,L-lactide-co-glycolide) (PLGA) microparticles. Salivary IgA and serum IgG responses after three daily oral immunizations in BALB/c mice were assayed by ELISA at weekly intervals and compared with those to soluble antigen. Low levels of salivary IgA antibodies were detected at Weeks 2 and 3 in both groups and no significant differences were found. After a secondary series of intragastric immunizations at Week 4, marked differences were apparent between the groups. The mean salivary IgA titre at Week 6 was 959 +/- 494 U compared with 30 +/- 5 in the soluble OVA group (P less than 0.0001). Significant differences were still apparent at Weeks 7-8 through the value was falling. Serum IgG antibodies were detectable and were significantly greater in the particle group (at Weeks 4 and 8) than in controls (P less than 0.001). These results suggest that microparticles are taken up by antigen-presenting cells in Peyer's patches, then slowly degrade in vivo and release entrapped antigens, and thus can function as potent antigen delivery systems giving rise to both mucosal and systemic responses. Microparticles have considerable potential as a controlled released antigen delivery system for the induction of longer-term immune responses at mucosal surfaces. PMID:1628895

  1. PLGA-PEG-PLGA microspheres as a delivery vehicle for antisense oligonucleotides to CTGF: Implications on post-surgical peritoneal adhesion prevention

    NASA Astrophysics Data System (ADS)

    Azeke, John Imuetinyan-Jesu, Jr.

    , while both cytokines are over-expressed within the first day following injury, CTGF protein levels could not be correlated with observed adhesion development. In addition, we synthesized linear triblock copolymers of polyethylene glycol (PEG) and poly(D,L-lactide-co-glycolide) (PLGA), two of the most widely studied biodegradable polymers in use today. Bulk gels and microparticles of the copolymers were then evaluated for gelling behavior, temperature stability, and drug loading and release kinetics in order assess their suitability as potential carriers of antisense therapeutics. A novel approach to affecting the antisense oligonucleotide release kinetics by varying the relative concentrations of co-encapsulated cationic lipid transfection agents was also presented.

  2. Improvement of an encapsulation process for the preparation of pro- and prebiotics-loaded bioadhesive microparticles by using experimental design.

    PubMed

    Pliszczak, D; Bourgeois, S; Bordes, C; Valour, J P; Mazoyer, M A; Orecchioni, A M; Nakache, E; Lantéri, P

    2011-09-18

    The purpose of this study was to design a new vaginal bioadhesive delivery system based on pectinate-hyaluronic acid microparticles for probiotics and prebiotics encapsulation. Probiotic strains and prebiotic were selected for their abilities to restore vaginal ecosystem. Microparticles were produced by emulsification/gelation method using calcium as cross-linking agent. In the first step, preliminary experiments were conducted to study the influence of the main formulation and process parameters on the size distribution of unloaded microparticles. Rheological measurements were also performed to investigate the bioadhesive properties of the gels used to obtain the final microparticles. Afterwards an experimental design was performed to determine the operating conditions suitable to obtain bioadhesive microparticles containing probiotics and prebiotics. Experimental design allowed us to define two important parameters during the microencapsulation process: the stirring rate during the emulsification step and the pectin concentration. The final microparticles had a mean diameter of 137μm and allowed a complete release of probiotic strains after 16h in a simulated vaginal fluid at +37°C.

  3. Effect of alginate composition on profile release and characteristics of chitosan-alginate microparticles loaded with mangosteen extract

    NASA Astrophysics Data System (ADS)

    Mulia, Kamarza; Halimah, Nur; Krisanti, Elsa

    2017-03-01

    Preparation of mangostin-loaded chitosan-alginate microparticles, chemical and physical characterization of the particles, and mangostin release profiles, are described herein. Mangostin rich fraction was obtained from Garcinia mangostana L. pericarp by extraction followed by fractionation. Mangostin-loaded chitosan-alginate microparticles were prepared by ionic gelation method using tripolyphosphate as the linking agent and various concentration of alginate. Mangostin was effectively loaded in all microparticle formulations, resulting in ˜97% encapsulation efficiencies. The loading of mangostin and the in-vitro release profiles in simulated gastrointestinal fluids were affected by the chitosan to alginate ratios used in the preparation of the microparticles. Increased alginate concentration resulted in lowered release of mangostin from microparticles immersed in simulated gastric fluid (pH 1.2) up to two hours. Low release of mangostin in acidic fluid but high release in simulated colon fluid, indicated that the chitosan-alginate microparticles are prospective carrier for extended release of active compound in gastrointestinal system.

  4. A Novel High Mechanical Property PLGA Composite Matrix Loaded with Nanodiamond-Phospholipid Compound for Bone Tissue Engineering.

    PubMed

    Zhang, Fan; Song, Qingxin; Huang, Xuan; Li, Fengning; Wang, Kun; Tang, Yixing; Hou, Canglong; Shen, Hongxing

    2016-01-20

    A potential bone tissue engineering material was produced from a biodegradable polymer, poly(lactic-co-glycolic acid) (PLGA), loaded with nanodiamond phospholipid compound (NDPC) via physical mixing. On the basis of hydrophobic effects and physical absorption, we modified the original hydrophilic surface of the nanodiamond (NDs) with phospholipids to be amphipathic, forming a typical core-shell structure. The ND-phospholipid weight ratio was optimized to generate sample NDPC50 (i.e., ND-phospholipid weight ratio of 100:50), and NDPC50 was able to be dispersed in a PLGA matrix at up to 20 wt %. Compared to a pure PLGA matrix, the introduction of 10 wt % of NDPC (i.e., sample NDPC50-PF10) resulted in a significant improvement in the material's mechanical and surface properties, including a decrease in the water contact angle from 80 to 55°, an approximately 100% increase in the Young's modulus, and an approximate 550% increase in hardness, thus closely resembling that of human cortical bone. As a novel matrix supporting human osteoblast (hFOB1.19) growth, NDPC50-PFs with different amounts of NDPC50 demonstrated no negative effects on cell proliferation and osteogenic differentiation. Furthermore, we focused on the behaviors of NDPC-PFs implanted into mice for 8 weeks and found that NDPC-PFs induced acceptable immune response and can reduce the rapid biodegradation of PLGA matrix. Our results represent the first in vivo research on ND (or NDPC) as nanofillers in a polymer matrix for bone tissue engineering. The high mechanical properties, good in vitro and in vivo biocompatibility, and increased mineralization capability suggest that biodegradable PLGA composite matrices loaded with NDPC may potentially be useful for a variety of biomedical applications, especially bone tissue engineering.

  5. Exploring the dark side of MTT viability assay of cells cultured onto electrospun PLGA-based composite nanofibrous scaffolding materials.

    PubMed

    Qi, Ruiling; Shen, Mingwu; Cao, Xueyan; Guo, Rui; Tian, Xuejiao; Yu, Jianyong; Shi, Xiangyang

    2011-07-21

    One major method used to evaluate the biocompatibility of porous tissue engineering scaffolding materials is MTT (3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay. The MTT cell viability assay is based on the absorbance of the dissolved MTT formazan crystals formed in living cells, which is proportional to the number of viable cells. Due to the strong dye sorption capability of porous scaffolding materials, we propose that the cell viability determined from the MTT assay is likely to give a false negative result. In this study, we aim to explore the effect of the adsorption of MTT formazan on the accuracy of the viability assay of cells cultured onto porous electrospun poly(lactic-co-glycolic acid) (PLGA) nanofibers, HNTs (halloysite nanotubes)/PLGA, and CNTs (multiwalled carbon nanotubes)/PLGA composite nanofibrous mats. The morphology of electrospun nanofibers and L929 mouse fibroblasts cultured onto the nanofibrous scaffolds were observed using scanning electron microscopy. The viability of cells proliferated for 3 days was evaluated through the MTT assay. In the meantime, the adsorption of MTT formazan onto the same electrospun nanofibers was evaluated and the standard concentration-absorbance curve was obtained in order to quantify the contribution of the adsorbed MTT formazan during the MTT cell viability assay. We show that the PLGA, and the HNTs- or CNTs-doped PLGA nanofibers display appreciable MTT formazan dye sorption, corresponding to 35.6-50.2% deviation from the real cell viability assay data. The better dye sorption capability of the nanofibers leads to further deviation from the real cell viability. Our study gives a general insight into accurate MTT cytotoxicity assessment of various porous tissue engineering scaffolding materials, and may be applicable to other colorimetric assays for analyzing the biological properties of porous scaffolding materials.

  6. Delivery of multiple siRNAs using lipid-coated PLGA nanoparticles for treatment of prostate cancer.

    PubMed

    Hasan, Warefta; Chu, Kevin; Gullapalli, Anuradha; Dunn, Stuart S; Enlow, Elizabeth M; Luft, J Christopher; Tian, Shaomin; Napier, Mary E; Pohlhaus, Patrick D; Rolland, Jason P; DeSimone, Joseph M

    2012-01-11

    Nanotechnology can provide a critical advantage in developing strategies for cancer management and treatment by helping to improve the safety and efficacy of novel therapeutic delivery vehicles. This paper reports the fabrication of poly(lactic acid-co-glycolic acid)/siRNA nanoparticles coated with lipids for use as prostate cancer therapeutics made via a unique soft lithography particle molding process called Particle Replication In Nonwetting Templates (PRINT). The PRINT process enables high encapsulation efficiency of siRNA into neutral and monodisperse PLGA particles (32-46% encapsulation efficiency). Lipid-coated PLGA/siRNA PRINT particles were used to deliver therapeutic siRNA in vitro to knockdown genes relevant to prostate cancer.

  7. Delivery of Multiple siRNAs Using Lipid-coated PLGA Nanoparticles for Treatment of Prostate Cancer

    PubMed Central

    Hasan, Warefta; Chu, Kevin; Gullapalli, Anuradha; Dunn, Stuart S.; Enlow, Elizabeth M.; Luft, J. Christopher; Tian, Shaomin; Napier, Mary E.; Pohlhaus, Patrick D.; Rolland, Jason P.; DeSimone, Joseph M.

    2012-01-01

    Nanotechnology can provide a critical advantage in developing strategies for cancer management and treatment by helping to improve the safety and efficacy of novel therapeutic delivery vehicles. This paper reports the fabrication of poly(lactic acid-co-glycolic acid)/siRNA nanoparticles coated with lipids for use as prostate cancer therapeutics made via a unique soft lithography particle molding process called PRINT (Particle Replication In Nonwetting Templates). The PRINT process enables high encapsulation efficiency of siRNA into neutral and monodisperse PLGA particles (32–46% encapsulation efficiency). Lipid-coated PLGA/siRNA PRINT particles were used to deliver therapeutic siRNA in vitro to knockdown genes relevant to prostate cancer. PMID:22165988

  8. Protective efficacy of PLGA microspheres loaded with divalent DNA vaccine encoding the ompA gene of Aeromonas veronii and the hly gene of Aeromonas hydrophila in mice.

    PubMed

    Gao, Shanshan; Zhao, Na; Amer, Said; Qian, Mingming; Lv, Mengxi; Zhao, Yuliang; Su, Xin; Cao, Jieying; He, Hongxuan; Zhao, Baohua

    2013-11-19

    In the present study, poly (lactic-co-glycolic) acid (PLGA) was used as a carrier for a divalent fusion DNA vaccine encoding the Aeromonas veronii outer membrane protein A (ompA) and Aeromonas hydrophila hemolysins (hly) protein. The recombinant pET-28a-ompA-hly was constructed by inserting the ompA gene and hly gene into a pET-28a expression vector. Loading of ompA-hly antigen module on PLGA microspheres were accomplished by water-in-oil-in-water (W/O/W) encapsulation. The molecular weight and specificity of pET-28a-ompA-hly were detected by dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and western blotting. The microspheres showed an average particle size of 100-150 μm and a loading efficiency (LE) of 68.8%. Mice received ompA-hly antigen-loaded PLGA microspheres by intraperitoneal or intragastric administration mounted strong and sustained IgG response, which was significantly higher (p<0.05) than those achieved by pET-28a-ompA-hly antigen alone. OmpA-hly antigen-loaded PLGA microsphere vaccine uniquely conferred a long lasting (30 days) sterile immunity against challenge infection. Results indicated that ompA-hly antigen-loaded PLGA microsphere vaccine is a qualified candidate vector system for sterile protective immunity against A. hydrophila and A. veronii infections.

  9. Poly(Lactic-co-Glycolic) Acid as a Carrier for Imaging Contrast Agents

    PubMed Central

    Doiron, Amber L.; Homan, Kimberly A.; Emelianov, Stanislav; Brannon-Peppas, Lisa

    2010-01-01

    Purpose With the broadening field of nanomedicine poised for future molecular level therapeutics, nano-and microparticles intended for the augmentation of either single- or multimodal imaging are created with PLGA as the chief constituent and carrier. Methods Emulsion techniques were used to encapsulate hydrophilic and hydrophobic imaging contrast agents in PLGA particles. The imaging contrast properties of these PLGA particles were further enhanced by reducing silver onto the PLGA surface, creating a silver cage around the polymeric core. Results The MRI contrast agent Gd-DTPA and the exogenous dye rhodamine 6G were both encapsulated in PLGA and shown to enhance MR and fluorescence contrast, respectively. The silver nanocage built around PLGA nanoparticles exhibited strong near infrared light absorbance properties, making it a suitable contrast agent for optical imaging strategies such as photoacoustic imaging. Conclusions The biodegradable polymer PLGA is an extremely versatile nano- and micro-carrier for several imaging contrast agents with the possibility of targeting diseased states at a molecular level. PMID:19034628

  10. Circulating microparticles: square the circle

    PubMed Central

    2013-01-01

    Background The present review summarizes current knowledge about microparticles (MPs) and provides a systematic overview of last 20 years of research on circulating MPs, with particular focus on their clinical relevance. Results MPs are a heterogeneous population of cell-derived vesicles, with sizes ranging between 50 and 1000 nm. MPs are capable of transferring peptides, proteins, lipid components, microRNA, mRNA, and DNA from one cell to another without direct cell-to-cell contact. Growing evidence suggests that MPs present in peripheral blood and body fluids contribute to the development and progression of cancer, and are of pathophysiological relevance for autoimmune, inflammatory, infectious, cardiovascular, hematological, and other diseases. MPs have large diagnostic potential as biomarkers; however, due to current technological limitations in purification of MPs and an absence of standardized methods of MP detection, challenges remain in validating the potential of MPs as a non-invasive and early diagnostic platform. Conclusions Improvements in the effective deciphering of MP molecular signatures will be critical not only for diagnostics, but also for the evaluation of treatment regimens and predicting disease outcomes. PMID:23607880

  11. Poly-(lactic-co-glycolic-acid)-based particulate vaccines: particle uptake by dendritic cells is a key parameter for immune activation.

    PubMed

    Silva, A L; Rosalia, R A; Varypataki, E; Sibuea, S; Ossendorp, F; Jiskoot, W

    2015-02-11

    Poly(lactic-co-glycolic acid) (PLGA) particles have been extensively studied as biodegradable delivery system to improve the potency and safety of protein-based vaccines. In this study we analyzed how the size of PLGA particles, and hence their ability to be engulfed by dendritic cells (DC), affects the type and magnitude of the immune response in comparison to sustained release from a local depot. PLGA microparticles (MP, volume mean diameter≈112 μm) and nanoparticles (NP, Z-average diameter≈350 nm) co-encapsulating ovalbumin (OVA) and poly(I:C), with comparable antigen (Ag) release characteristics, were prepared and characterized. The immunogenicity of these two distinct particulate vaccines was evaluated in vitro and in vivo. NP were efficiently taken up by DC and greatly facilitated MHC I Ag presentation in vitro, whereas DC cultured in the presence of MP failed to internalize significant amounts of Ag and hardly showed MHC I Ag presentation. Vaccination of mice with NP resulted in significantly better priming of Ag-specific CD8(+) T cells compared to MP and OVA emulsified with incomplete Freund's adjuvant (IFA). Moreover, NP induced a balanced TH1/TH2-type antibody response, compared to vaccinations with IFA which stimulated a predominant TH2-type response, whereas MP failed to increase antibody titers. In conclusion, we postulate that particle internalization is of crucial importance and therefore particulate vaccines should be formulated in the nano- but not micro-size range to achieve efficient uptake, significant MHC class I cross-presentation and effective T and B cell responses.

  12. The content of DNA and RNA in microparticles released by Jurkat and HL-60 cells undergoing in vitro apoptosis

    SciTech Connect

    Reich, Charles F.; Pisetsky, David S.

    2009-03-10

    Microparticles are small membrane-bound vesicles that are released from apoptotic cells during blebbing. These particles contain DNA and RNA and display important functional activities, including immune system activation. Furthermore, nucleic acids inside the particle can be analyzed as biomarkers in a variety of disease states. To elucidate the nature of microparticle nucleic acids, DNA and RNA released in microparticles from the Jurkat T and HL-60 promyelocytic cell lines undergoing apoptosis in vitro were studied. Microparticles were isolated from culture media by differential centrifugation and characterized by flow cytometry and molecular approaches. In these particles, DNA showed laddering by gel electrophoresis and was present in a form that allowed direct binding by a monoclonal anti-DNA antibody, suggesting antigen accessibility even without fixation. Analysis of RNA by gel electrophoresis showed intact 18s and 28s ribosomal RNA bands, although lower molecular bands consistent with 28s ribosomal RNA degradation products were also present. Particles also contained messenger RNA as shown by RT-PCR amplification of sequences for {beta}-actin and GAPDH. In addition, gel electrophoresis showed the presence of low molecular weight RNA in the size range of microRNA. Together, these results indicate that microparticles from apoptotic Jurkat and HL-60 cells contain diverse nucleic acid species, indicating translocation of both nuclear and cytoplasmic DNA and RNA as particle release occurs during death.

  13. Doxycycline hyclate-loaded bleached shellac in situ forming microparticle for intraperiodontal pocket local delivery.

    PubMed

    Phaechamud, Thawatchai; Chanyaboonsub, Nuttapong; Setthajindalert, Orn

    2016-10-10

    Bleached shellac (BS) is a water-insoluble polyester resin made up of sesquiterpenoid acids esterified with hydroxy aliphatic acids. In this study, BS dissolved in N-methyl pyrrolidone (NMP), dimethyl sulfoxide (DMSO) and 2-pyrrolidone was used as the internal phase of oil in oil emulsion using olive oil emulsified with glyceryl monostearate (GMS) as the external phase of in situ forming microparticles (ISM). Doxycycline hyclate (DH)-loaded BS ISMs were tested for emulsion stability, viscosity, rheology, transformation into microparticles, syringeability, drug release, surface topography, in vitro degradation and antimicrobial activities against Staphylococcus aureus, Streptococcus mutans and Porphyromonas gingivalis. All emulsions exhibited pseudoplastic flow and notably low syringeability force. Slower transformation from emulsion into microparticles of ISM prepared with 2-pyrrolidone was owing to slower solvent exchange of this solvent which promoted less porous structure of obtained BS matrix microparticles. The system containing 2-pyrrolidone exhibited a higher degradability than that prepared with DMSO. Developed DH-loaded BS ISMs exhibited a sustainable drug release for 47days with Fickian diffusion and effectively inhibited P. gingivalis, S. mutans and S. aureus. Therefore a DH-loaded BS ISM using olive oil containing GMS as the external phase and 2-pyrrolidone as a solvent was a suitable formulation for periodontitis treatment.

  14. Evaluation of PLGA containing anti-CTLA4 inhibited endometriosis progression by regulating CD4+CD25+Treg cells in peritoneal fluid of mouse endometriosis model.

    PubMed

    Liu, Qi; Ma, Pingchuan; Liu, Lanxia; Ma, Guilei; Ma, Jingjing; Liu, Xiaoxuan; Liu, Yijin; Lin, Wanjun; Zhu, Yingjun

    2017-01-01

    Our study investigated poly(lactic-co-glycolic acid) (PLGA) as protein delivery vehicles encapsulate CTLA-4-antibody (anti-CTLA-4) which is essential for CD4+CD25+Treg cells suppressive function exposing superior potential for inhibiting endometriosis progress in mouse model than single anti-CTLA-4. Anti-CTLA-4 loaded PLGA combined to ligands CTLA-4 in surface of CD4+CD25+Treg cells which distributed in peritoneal fluid of mouse endometriosis model. The particle size, zeta potential of the anti-CTLA-4 loaded nanoparticles was detected by dynamic light scattering. Morphology of nanoparticles was evaluated by transmission electron microscopy (TEM). Confocal laser scanning microscopy (CLSM) indicated distribution of anti-CTLA-4 with PLGA or without in peritoneal fluid. Cumulative anti-CTLA-4 release from nanoparticles was evaluated by Micro BCA assay. The percentage of CD4+CD25+Treg cells in peritoneal fluid was demonstrated by flow cytometer. In vitro experiment we co-culture ectopic endometrial cells (EEC) with isolated CD4+CD25+Treg cells in peritoneal fluid (PF), proliferation and invasion of ectopic endometrial cells (EEC) was measured by BrdU ELISA assay and Matrigel invasion assay. In comparison with anti-CTLA-4 without nanoparticles, the bioconjugates PLGA/anti-CTLA-4 were tolerated in peritoneal fluid with a controlled release of anti-CTLA-4 in 3, 7, 14days. Moreover, PLGA/anti-CTLA-4 had superior protective regulation ability to reduce level of CD4+CD25+Treg cells in peritoneal fluid. Most strikingly, in vitro experiment, PLGA/anti-CTLA-4 exhibited better ability in inhibiting proliferation and invasion of ectopic endometrial cells in co-culture system compared with anti-CTLA-4. Progressively, PLGA/anti-CTLA-4 had better suppressive activity to inhibited IL-10 and TGF-beta secreted by CD4+CD25+Treg cells which indicating that PLGA/anti-CTLA-4 suppressed cells proliferation and invasion through reduced IL-10 and TGF-beta production. Thus, PLGA/anti-CTLA-4 may

  15. Thermal property and assessment of biocompatibility of poly(lactic-co-glycolic) acid/graphene nanocomposites

    NASA Astrophysics Data System (ADS)

    Adhikari, Ananta R.; Rusakova, Irene; Haleh, Ardebili; Luisi, Jonathan; Panova, Neli I.; Laezza, Fernanda; Chu, Wei-Kan

    2014-02-01

    Polymer-matrix nanocomposites based on Poly(lactic-co-glycolic) acid (PLGA) and Graphene platelets (GNPs) were studied. GNPs, nanomaterials with a 2D flat surface, were chosen with or without chemical modification in PLGA/GNP nanocomposites and their microstructure, thermal property, and their compatibility as scaffolds for cell growth were investigated. PLGA/GNP nanocomposites (0, 1, and 5 wt. % of GNPs) were prepared using a solution based technique. Transmission electron microscopy, X-ray diffraction, Differential scanning calorimeter, and Thermogravimetric analyzer were used to analyze morphology and thermal properties. This work demonstrated the role of GNPs flat surface to provide a favorable platform resulting in an enhanced PLGA crystallization. Functionalized GNPs suppress both the thermal stability and the crystallization of PLGA. Finally, to determine the potential usefulness of these scaffolds for biomedical applications, mammalian cells were cultured on various PLGA/GNP nanocomposites (0, 1, and 5 wt. % GNPs). 1 wt. % PLGA/GNP nanocomposites showed better biocompatibility for cell growth with/without graphenes functionalization compared to pure PLGA and 5 wt. % PLGA/GNP. The function of GNPs in PLGA/GNPs (1 wt. %) composites is to provide a stage for PLGA crystallization where cell growth is favored. These results provide strong evidence for a new class of materials that could be important for biomedical applications.

  16. Thermal property and assessment of biocompatibility of poly(lactic-co-glycolic) acid/graphene nanocomposites

    SciTech Connect

    Adhikari, Ananta R.; Rusakova, Irene; Chu, Wei-Kan; Haleh, Ardebili; Luisi, Jonathan; Panova, Neli I.; Laezza, Fernanda

    2014-02-07

    Polymer-matrix nanocomposites based on Poly(lactic-co-glycolic) acid (PLGA) and Graphene platelets (GNPs) were studied. GNPs, nanomaterials with a 2D flat surface, were chosen with or without chemical modification in PLGA/GNP nanocomposites and their microstructure, thermal property, and their compatibility as scaffolds for cell growth were investigated. PLGA/GNP nanocomposites (0, 1, and 5 wt. % of GNPs) were prepared using a solution based technique. Transmission electron microscopy, X-ray diffraction, Differential scanning calorimeter, and Thermogravimetric analyzer were used to analyze morphology and thermal properties. This work demonstrated the role of GNPs flat surface to provide a favorable platform resulting in an enhanced PLGA crystallization. Functionalized GNPs suppress both the thermal stability and the crystallization of PLGA. Finally, to determine the potential usefulness of these scaffolds for biomedical applications, mammalian cells were cultured on various PLGA/GNP nanocomposites (0, 1, and 5 wt. % GNPs). 1 wt. % PLGA/GNP nanocomposites showed better biocompatibility for cell growth with/without graphenes functionalization compared to pure PLGA and 5 wt. % PLGA/GNP. The function of GNPs in PLGA/GNPs (1 wt. %) composites is to provide a stage for PLGA crystallization where cell growth is favored. These results provide strong evidence for a new class of materials that could be important for biomedical applications.

  17. Janus nanogels of PEGylated Taxol and PLGA-PEG-PLGA copolymer for cancer therapy

    NASA Astrophysics Data System (ADS)

    Wei, Jun; Wang, Huaimin; Zhu, Meifeng; Ding, Dan; Li, Dongxia; Yin, Zhinan; Wang, Lianyong; Yang, Zhimou

    2013-09-01

    Nanogels are promising carriers for the delivery of anti-cancer drugs for cancer therapy. We report in this study on a Janus nanogel system formed by mixing a prodrug of Taxol (PEGylated Taxol) and a copolymer of PLGA-PEG-PLGA. The Janus nanogels have good stability over months in aqueous solutions and the freeze-dried powder of nanogels can be re-dispersed instantly in aqueous solutions. The Janus nanogels show an enhanced inhibition effect on tumor growth in a mice breast cancer model probably due to the enhanced uptake of the nano-sized materials by the EPR effect. What is more, the nanogels can also serve as physical carriers to co-deliver other anti-cancer drugs such as doxorubicin to further improve the anti-cancer efficacy. The results obtained from H&E staining and TUNEL assay also support the observation of tumor growth inhibition. These results suggest the potential of this novel delivery system for cancer therapy.Nanogels are promising carriers for the delivery of anti-cancer drugs for cancer therapy. We report in this study on a Janus nanogel system formed by mixing a prodrug of Taxol (PEGylated Taxol) and a copolymer of PLGA-PEG-PLGA. The Janus nanogels have good stability over months in aqueous solutions and the freeze-dried powder of nanogels can be re-dispersed instantly in aqueous solutions. The Janus nanogels show an enhanced inhibition effect on tumor growth in a mice breast cancer model probably due to the enhanced uptake of the nano-sized materials by the EPR effect. What is more, the nanogels can also serve as physical carriers to co-deliver other anti-cancer drugs such as doxorubicin to further improve the anti-cancer efficacy. The results obtained from H&E staining and TUNEL assay also support the observation of tumor growth inhibition. These results suggest the potential of this novel delivery system for cancer therapy. Electronic supplementary information (ESI) available: Synthesis and characterization of compounds, dynamic time sweep, H

  18. A Novel Method for Preparing Surface-Modified Fluocinolone Acetonide Loaded PLGA Nanoparticles for Ocular Use: In Vitro and In Vivo Evaluations.

    PubMed

    Salama, Alaa H; Mahmoud, Azza A; Kamel, Rabab

    2016-10-01

    Our objective was to prepare nanoparticulate system using a simple yet attractive innovated method as an ophthalmic delivery system for fluocinolone acetonide to improve its ocular bioavailability. Poly(lactic-co-glycolic acid) (PLGA) nanoparticles were prepared by adopting thin film hydration method using PLGA/poloxamer 407 in weight ratios of 1:5 and 1:10. PLGA was used in 75/25 and 50/50 copolymer molar ratio of DL-lactide/glycolide. Results revealed that using PLGA with lower glycolic acid monomer ratio exhibited high particle size (PS), zeta potential (ZP) and drug encapsulation efficiency (EE) values with slow drug release pattern. Also, doubling the drug concentration during nanoparticles preparation ameliorated its EE to reach almost 100%. Furthermore, studies for separating the un-entrapped drug in nanoparticles using centrifugation method at 20,000 rpm for 30 min showed that the separated clear supernatant contained nanoparticles encapsulating an important drug amount. Therefore, separation of un-entrapped drug was carried out by filtrating the preparation using 20-25 μm pore size filter paper to avoid drug loss. Aiming to increase the PLGA nanoparticles mucoadhesion ability, surface modification of selected formulation was done using different amount of stearylamine and chitosan HCl. Nanoparticles coated with 0.1% w/v chitosan HCl attained most suitable results of PS, ZP and EE values as well as high drug release properties. Transmission electron microphotographs illustrated the deposition of chitosan molecules on the nanoparticles surfaces. Pharmacokinetic studies on Albino rabbit's eyes using HPLC indicated that the prepared novel chitosan-coated PLGA nanoparticles subjected to separation by filtration showed rapid and extended drug delivery to the eye.

  19. Mechanisms of in vivo release of triamcinolone acetonide from PLGA microspheres.

    PubMed

    Doty, Amy C; Weinstein, David G; Hirota, Keiji; Olsen, Karl F; Ackermann, Rose; Wang, Yan; Choi, Stephanie; Schwendeman, Steven P

    2017-03-22

    Little is known about the underlying effects controlling in vitro-in vivo correlations (IVIVCs) for biodegradable controlled release microspheres. Most reports of IVIVCs that exist are empirical in nature, typically based on a mathematical relationship between in vitro and in vivo drug release, with the latter often estimated by deconvolution of pharmacokinetic data. In order to improve the ability of in vitro release tests to predict microsphere behavior in vivo and develop more meaningful IVIVCs, the in vivo release mechanisms need to be characterized. Here, two poly(lactic-co-glycolic acid) (PLGA) microsphere formulations encapsulating the model steroid triamcinolone acetonide (Tr-A) were implanted subcutaneously in rats by using a validated cage model, allowing for free fluid and cellular exchange and microsphere retrieval during release. Release kinetics, as well as mechanistic indicators of release such as hydrolysis and mass loss, was measured by direct analysis of the recovered microspheres. Release of Tr-A from both formulations was greatly accelerated in vivo compared to in vitro using agitated phosphate buffered saline +0.02% Tween 80 pH7.4, including rate of PLGA hydrolysis, mass loss and water uptake. Both microsphere formulations exhibited erosion-controlled release in vitro, indicated by similar polymer mass loss kinetics, but only one of the formulations (low molecular weight, free acid terminated) exhibited the same mechanism in vivo. The in vivo release of Tr-A from microspheres made of a higher molecular weight, ester end-capped PLGA displayed an osmotically induced/pore diffusion mechanism based on confocal micrographs of percolating pores in the polymer, not previously observed in vitro. This research indicates the need to fully understand the in vivo environment and how it causes drug release from biodegradable microspheres. This understanding can then be applied to develop in vitro release tests which better mimic this environment and cause

  20. Agglomeration of microparticles in complex plasmas

    SciTech Connect

    Du, Cheng-Ran; Thomas, Hubertus M.; Ivlev, Alexei V.; Konopka, Uwe; Morfill, Gregor E.

    2010-11-15

    Agglomeration of highly charged microparticles was observed and studied in complex plasma experiments carried out in a capacitively coupled rf discharge. The agglomeration was caused by strong waves triggered in a particle cloud by decreasing neutral gas pressure. Using a high-speed camera during this unstable regime, it was possible to resolve the motion of individual microparticles and to show that the relative velocities of some particles were sufficiently high to overcome the mutual Coulomb repulsion and hence to result in agglomeration. After stabilizing the cloud again through the increase of the pressure, we were able to observe the aggregates directly with a long-distance microscope. We show that the agglomeration rate deduced from our experiments is in good agreement with theoretical estimates. In addition, we briefly discuss the mechanisms that can provide binding of highly charged microparticles in a plasma.

  1. Microparticle trapping in an ultrasonic Bessel beam.

    PubMed

    Choe, Youngki; Kim, Jonathan W; Shung, K Kirk; Kim, Eun Sok

    2011-12-05

    This paper describes an acoustic trap consisting of a multi-foci Fresnel lens on 127 μm thick lead zirconate titanate sheet. The multi-foci Fresnel lens was designed to have similar working mechanism to an Axicon lens and generates an acoustic Bessel beam, and has negative axial radiation force capable of trapping one or more microparticle(s). The fabricated acoustic tweezers trapped lipid particles ranging in diameter from 50 to 200 μm and microspheres ranging in diameter from 70 to 90 μm at a distance of 2 to 5 mm from the tweezers without any contact between the transducer and microparticles.

  2. Microparticle trapping in an ultrasonic Bessel beam

    PubMed Central

    Choe, Youngki; Kim, Jonathan W.; Shung, K. Kirk; Kim, Eun Sok

    2011-01-01

    This paper describes an acoustic trap consisting of a multi-foci Fresnel lens on 127 μm thick lead zirconate titanate sheet. The multi-foci Fresnel lens was designed to have similar working mechanism to an Axicon lens and generates an acoustic Bessel beam, and has negative axial radiation force capable of trapping one or more microparticle(s). The fabricated acoustic tweezers trapped lipid particles ranging in diameter from 50 to 200 μm and microspheres ranging in diameter from 70 to 90 μm at a distance of 2 to 5 mm from the tweezers without any contact between the transducer and microparticles. PMID:22247566

  3. Alginate/polymethacrylate copolymer microparticles for the intestinal delivery of enzymes.

    PubMed

    Scocca, Sarah; Faustini, Massimo; Villani, Simona; Munari, Eleonora; Conte, Ubaldo; Russo, Vincenzo; Riccardi, Alessia; Vigo, Daniele; Torre, Maria Luisa

    2007-04-01

    Proteins administered orally must pass through the gastric environment in order to reach their site of absorption in the intestine. How to protect these exogenously administered proteins from the damaging effects of gastric acid and pepsin proteolytic activity, which often induce irreversible structural and functional alterations to the molecules, is an intriguing challenge. Another problem is the physical and chemical instability of proteins during some technological processes, which often involve the use of organic solvents or high temperatures. In this study we investigated the use of alginate microparticles containing one of two enzymes, an enteric polymer and a lyoprotectant for the intestinal delivery of proteins. The two enzymes tested in this protein delivery system were lactate dehydrogenase and alpha-amylase: the former was chosen because of its sensitivity to denaturation, the latter for its relevance in nutrition and medicine. A sodium alginate aqueous solution containing the enteric polymer, a lyoprotectant and the enzyme was either extruded or sprayed into a calcium chloride solution, with the resultant formation of beads and microspheres which were freeze-dried. About 90% of the enzyme activity was maintained during the process of loading the proteins into the microparticles and the subsequent freeze-drying process. The stability of the encapsulated enzyme in an acid medium and the enzymatic activity in an intestinal environment were then investigated by a dissolution test. This consisted of exposing the microparticles to simulated gastric fluid (pH 1.2) for 2 hours and to simulated intestinal fluid (pH 7.5+/-0.1) for 1 hour. The morphology of the microparticles did not change in the acid environment, whereas they completely dissolved within 3 min in the simulated intestinal fluid. Residual enzymatic activity after the test remained satisfactory for both enzymes. In conclusion, these microparticle systems offer promise for applications in human and

  4. Epigallocatechin-3-O-Gallate-Loaded Poly(lactic-co-glycolic acid) Fibrous Sheets as Anti-Adhesion Barriers.

    PubMed

    Lee, Jong Ho; Shin, Yong Cheol; Yang, Won Jun; Park, Jong-chul; Hyon, Suong-hyu; Han, Dong-wook

    2015-08-01

    Epigallocatechin-3-O-gallate (EGCG), the main polyphenolic component of green tea, has a wide range of pharmacological activities, including antioxidant, anti-inflammatory, and anti-fibrotic effects. In this study, EGCG-loaded poly(lactic-co-glycolic acid) (PLGA) sheets were prepared by electrospinning nanofibers and evaluating their potential as tissue-adhesion barriers. EGCG-loaded PLGA (E-PLGA) fibrous sheets were electrospun from a PLGA solution containing 8% (w/v) EGCG. The average diameter of E-PLGA fibers was 397 ± 159 nm, which was comparable to that of pure PLGA fibers (459 ± 154 nm). EGCG was uniformly dispersed in E-PLGA sheets without direct chemical interactions. E-PLGA fibrous sheets showed sustained release of EGCG by controlled diffusion and PLGA degradation. The attachment and proliferation of L-929 fibroblastic cells were significantly (p < 0.05) suppressed in E-PLGA sheets. Furthermore, E-PLGA fibrous sheets did not induce any inflammatory response to J774A.1 macrophages. The anti-adhesion efficacy of E-PLGA fibrous sheets was evaluated in the intraperitoneal adhesion model in rats. Two weeks after surgical treatment, macroscopic adhesion (extent and severity) scores and histopathological tissue responses of E-PLGA fibrous sheets were significantly lower than those of non-treated controls and pure PLGA sheets. The results suggest that the scores are comparable, and in some cases superior, to those of other commercialized tissue-adhesion barriers. In conclusion, our study findings suggest that E-PLGA fibrous sheets may be exploited as potential tissue-adhesion barriers for the prevention of post-surgical adhesion formation.

  5. Circulating Microparticles Alter Formation, Structure, and Properties of Fibrin Clots

    PubMed Central

    Zubairova, Laily D.; Nabiullina, Roza M.; Nagaswami, Chandrasekaran; Zuev, Yuriy F.; Mustafin, Ilshat G.; Litvinov, Rustem I.; Weisel, John W.

    2015-01-01

    Despite the importance of circulating microparticles in haemostasis and thrombosis, there is limited evidence for potential causative effects of naturally produced cell-derived microparticles on fibrin clot formation and its properties. We studied the significance of blood microparticles for fibrin formation, structure, and susceptibility to fibrinolysis by removing them from platelet-free plasma using filtration. Clots made in platelet-free and microparticle-depleted plasma samples from the same healthy donors were analyzed in parallel. Microparticles accelerate fibrin polymerisation and support formation of more compact clots that resist internal and external fibrinolysis. These variations correlate with faster thrombin generation, suggesting thrombin-mediated kinetic effects of microparticles on fibrin formation, structure, and properties. In addition, clots formed in the presence of microparticles, unlike clots from the microparticle-depleted plasma, contain 0.1–0.5-μm size granular and CD61-positive material on fibres, suggesting that platelet-derived microparticles attach to fibrin. Therefore, the blood of healthy individuals contains functional microparticles at the levels that have a procoagulant potential. They affect the structure and stability of fibrin clots indirectly through acceleration of thrombin generation and through direct physical incorporation into the fibrin network. Both mechanisms underlie a potential role of microparticles in haemostasis and thrombosis as modulators of fibrin formation, structure, and resistance to fibrinolysis. PMID:26635081

  6. Controlled release of simvastatin-loaded thermo-sensitive PLGA-PEG-PLGA hydrogel for bone tissue regeneration: in vitro and in vivo characteristics.

    PubMed

    Yan, Qi; Xiao, Li-Qun; Tan, Lei; Sun, Wei; Wu, Tao; Chen, Liang-Wen; Mei, Yan; Shi, Bin

    2015-11-01

    Reports on the local delivery of drug loaded injectable hydrogels for bone regeneration are currently limited. This study assessed the effect of controlled simvastatin (SIM) release from a thermo-sensitive hydrogel in vitro and in vivo. We successfully manufactured and evaluated thermo-sensitive poly(d,l-lactide-co-glycolide)-poly(ethylene glycol)-poly(d,l-lactide-co-glycolide) triblock copolymers (PLGA-PEG-PLGA) loaded with SIM. The osteogenic effect of this hydrogel was tested in vitro and in vivo. MC-3T3 E1 cells proliferation and osteoblastic differentiation was analyzed after cultivation with the hydrogel extracts. Cells co-cultured with SIM/PLGA-PEG-PLGA extracts showed an increase in mineralization and osteogenic gene expression compared to the other two groups. Additionally, the characteristics of this composite in vivo were demonstrated using a rat bone defect model. The bone defects injected with SIM/PLGA-PEG-PLGA hydrogel showed increased new bone formation compared to samples treated with PLGA-PEG-PLGA and control samples. The results of this study suggest that SIM/PLGA-PEG-PLGA might provide potential therapeutic value for bone healing.

  7. Microparticles: new light shed on the understanding of venous thromboembolism

    PubMed Central

    Zhou, Lin; Qi, Xiao-long; Xu, Ming-xin; Mao, Yu; Liu, Ming-lin; Song, Hao-ming

    2014-01-01

    Microparticles are small membrane fragments shed primarily from blood and endothelial cells during either activation or apoptosis. There is mounting evidence suggesting that microparticles perform a large array of biological functions and contribute to various diseases. Of these disease processes, a significant link has been established between microparticles and venous thromboembolism. Advances in research on the role of microparticles in thrombosis have yielded crucial insights into possible mechanisms, diagnoses and therapeutic targets of venous thromboembolism. In this review, we discuss the definition and properties of microparticles and venous thromboembolism, provide a synopsis of the evidence detailing the contributions of microparticles to venous thromboembolism, and propose potential mechanisms, by which venous thromboembolism occurs. Moreover, we illustrate a possible role of microparticles in cancer-related venous thromboembolism. PMID:25152025

  8. Strategy for the hemocompatibility testing of microparticles.

    PubMed

    Braune, S; Basu, S; Kratz, K; Johansson, J Bäckemo; Reinthaler, M; Lendlein, A; Jung, F

    2016-01-01

    Polymer-based microparticles are applied as non-thrombogenic or thrombogenic materials in a wide variety of intra- or extra-corporeal medical devices. As demanded by the regulatory agencies, the hemocompatibility of these blood contacting biomaterials has to be evaluated in vitro to ensure that the particle systems appropriately fulfill the envisioned function without causing undesired events such as thrombosis or inflammation. Currently described in vitro assays for hemocompatibility testing of particles comprise tests with different single cell types (e.g. erythrocytes or leukocytes), varying concentrations/dilutions of the used blood cells or whole blood, which are not standardized.Here, we report about an in vitro dynamic test system for studying the hemocompatibility of polymeric microparticles utilizing fresh human whole blood from apparently healthy subjects, collected and processed under standardized conditions. Spherical poly(ether imide) microparticles with an average diameter of 140±30 μm were utilized as model systems. Reported as candidate materials for the removal of uremic toxins, these microparticles are anticipated to facilitate optimal flow conditions in a dialyzer with minimal backflow and blood cell damage. Pristine (PEI) and potassium hydroxide (PEI-KOH) functionalized microparticles exhibited similarly nanoporous surfaces (PEI: ØExternal pore = 90±60 nm; PEI-KOH ØExternal pore = 150±130 nm) but varying water wettabilities (PEI: θadv = 112±10° PEI-KOH θadv = 60±2°). The nanoporosity of the microparticle surfaces allows the exchange of toxic solutes from blood towards the interconnective pores in the particle core, while an immigration of the substantially larger blood cells is inhibited.Sterilized PEI microparticles were incorporated -air-free -in a syringe-based test system and exposed to whole blood for 60 minutes under gentle agitation. Thereafter, thrombi formation on the particles surfaces were analyzed

  9. Photoprotective efficiency of PLGA-curcumin nanoparticles versus curcumin through the involvement of ERK/AKT pathway under ambient UV-R exposure in HaCaT cell line.

    PubMed

    Chopra, Deepti; Ray, Lipika; Dwivedi, Ashish; Tiwari, Shashi Kant; Singh, Jyoti; Singh, Krishna P; Kushwaha, Hari Narayan; Jahan, Sadaf; Pandey, Ankita; Gupta, Shailendra K; Chaturvedi, Rajnish Kumar; Pant, Aditya Bhushan; Ray, Ratan Singh; Gupta, Kailash Chand

    2016-04-01

    Curcumin (Cur) has been demonstrated to have wide pharmacological window including anti-oxidant and anti-inflammatory properties. However, phototoxicity under sunlight exposure and poor biological availability limits its applicability. We have synthesized biodegradable and non-toxic polymer-poly (lactic-co-glycolic) acid (PLGA) encapsulated formulation of curcumin (PLGA-Cur-NPs) of 150 nm size range. Photochemically free curcumin generates ROS, lipid peroxidation and induces significant UVA and UVB mediated impaired mitochondrial functions leading to apoptosis/necrosis and cell injury in two different origin cell lines viz., mouse fibroblasts-NIH-3T3 and human keratinocytes-HaCaT as compared to PLGA-Cur-NPs. Molecular docking studies suggested that intact curcumin from nanoparticles, bind with BAX in BIM SAHB site and attenuate it to undergo apoptosis while upregulating anti-apoptotic genes like BCL2. Real time studies and western blot analysis with specific phosphorylation inhibitor of ERK1 and AKT1/2/3 confirm the involvement of ERK/AKT signaling molecules to trigger the survival cascade in case of PLGA-Cur-NPs. Our finding demonstrates that low level sustained release of curcumin from PLGA-Cur-NPs could be a promising way to protect the adverse biological interactions of photo-degradation products of curcumin upon the exposure of UVA and UVB. Hence, the applicability of PLGA-Cur-NPs could be suggested as prolonged radical scavenging ingredient in curcumin containing products.

  10. Cytotoxicity assessment of porous silicon microparticles for ocular drug delivery.

    PubMed

    Korhonen, Eveliina; Rönkkö, Seppo; Hillebrand, Satu; Riikonen, Joakim; Xu, Wujun; Järvinen, Kristiina; Lehto, Vesa-Pekka; Kauppinen, Anu

    2016-03-01

    Porous silicon (PSi) is a promising material for the delivery and sustained release of therapeutic molecules in various tissues. Due to the constant rinsing of cornea by tear solution as well as the short half-life of intravitreal drugs, the eye is an attractive target for controlled drug delivery systems, such as PSi microparticles. Inherent barriers ensure that PSi particles are retained in the eye, releasing drugs at the desired speed until they slowly break down into harmless silicic acid. Here, we have examined the in vitro cytotoxicity of positively and negatively charged thermally oxidized (TOPSi) and thermally carbonized (TCPSi) porous silicon microparticles on human corneal epithelial (HCE) and retinal pigment epithelial (ARPE-19) cells. In addition to ocular assessment under an inverted microscope, cellular viability was evaluated using the CellTiter Blue™, CellTiter Fluor™, and lactate dehydrogenase (LDH) assays. CellTiter Fluor proved to be a suitable assay but due to non-specific and interfering responses, neither CellTiter Blue nor LDH assays should be used when evaluating PSi particles. Our results suggest that the toxicity of PSi particles is concentration-dependent, but at least at concentrations less than 200μg/ml, both positively and negatively charged PSi particles are well tolerated by human corneal and retinal epithelial cells and therefore applicable for delivering drug molecules into ocular tissues.

  11. Dopamine-conjugated poly(lactic-co-glycolic acid) nanoparticles for protein delivery to macrophages.

    PubMed

    Lee, Song Yi; Cho, Hyun-Jong

    2017-03-15

    Poly(lactic-co-glycolic acid)-dopamine (PLGA-D)-based nanoparticles (NPs) were developed for the delivery of protein to macrophages. PLGA-D was synthesized via amide bond formation between the amine group of D and the carboxylic acid group of PLGA. Bovine serum albumin (BSA, model protein) was encapsulated in PLGA NPs and PLGA-D NPs, which had an approximately 200nm mean diameter, <0.2 polydispersity index, and negative zeta potential value. There was no increment in the mean diameters of BSA-loaded NPs after 24h of incubation in biological fluid-simulated media (i.e., aqueous buffer and serum media). The primary, secondary, and tertiary structures of BSA released from the NPs were studied by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), circular dichroism, and fluorescence spectrophotometry; the structural stability of BSA was preserved during its encapsulation in the NPs and release from the NPs. PLGA/BSA NPs and PLGA-D/BSA NPs did not induce serious cytotoxicity in RAW 264.7 cells (mouse macrophage cell line) in an established concentration range. In RAW 264.7 cells, the intracellular accumulation of PLGA-D NPs was 2-fold higher than that of PLGA NPs. All of these findings indicated that PLGA-D NPs are a promising system for delivering proteins to macrophages.

  12. HPLC-UV method development and validation for the quantification of ropinirole in new PLGA multiparticulate systems: Microspheres and nanoparticles.

    PubMed

    Fuster, J; Negro, S; Salama, A; Fernández-Carballido, A; Marcianes, P; Boeva, L; Barcia, E

    2015-08-01

    A simple HPLC-UV method was developed and validated for the quantitation of RP free base encapsulated into two new multiparticulate systems (microparticles and nanoparticles), as well as for the quantification of RP hydrochloride when given as a loading dose together with the new delivery system developed. HPLC separation was achieved using a C18 Kromasil column (250 mm × 4 mm) with a mobile phase composed of acetonitrile-phosphate buffer solution (55:45, v/v) adjusted at pH 6.0 and containing 0.3% triethanolamine. Flow rate was set at 1.0 mL min(-1). The UV detector was operated at 245 nm. The method allowed for the simultaneous determination of both RP and RP-HCl. The method was linear within the range 2.5-50 μg mL(-1) for both RP and RP-HCl. The limits of detection (LOD) and quantitation (LOQ) found were 0.8 μg mL(-1) and 2.4 μg mL(-1) for RP, and 0.3 μg mL(-1) and 0.9 μg mL(-1) for RP-HCl. The method was found to be simple, rapid, specific, precise, accurate, and reproducible. The method was successfully applied to the determination of the encapsulation efficiency of RP in the multiparticulate systems developed, being 85.03 ± 3.77% and 51.12 ± 3.50%, for RP-loaded PLGA microspheres and RP-loaded PLGA nanoparticles, respectively.

  13. Effect of polymer porosity on aqueous self-healing encapsulation of proteins in PLGA microspheres.

    PubMed

    Reinhold, Samuel E; Schwendeman, Steven P

    2013-12-01

    Self-healing (SH) poly(lactic-co-glycolic acid) (PLGA) microspheres are a unique class of functional biomaterials capable of microencapsulating process-sensitive proteins by simple mixing and heating the drug-free polymer in aqueous protein solution. Drug-free SH microspheres of PLGA 50/50 with percolating pore networks of varying porosity (ϵ = 0.49-73) encapsulate increasing lysozyme (≈1 to 10% w/w) with increasing ϵ, with typically ≈20 to 25% pores estimated accessible to entry by the enzyme from the external solution. Release kinetics of lysozyme under physiological conditions is continuous over more than two weeks and most strongly influenced by ϵ and protein loading before reaching a lag phase until 28 d at the study completion. Recovered enzyme after release is typically predominantly monomeric and active. Formulations containing acid-neutralizing MgCO3 at ≥ 4.3% exhibit >97% monomeric and active protein after the release with full mass balance recovery. Hence, control of SH polymer ϵ is a key parameter to development of this new class of biomaterials.

  14. Injectable and porous PLGA microspheres that form highly porous scaffolds at body temperature.

    PubMed

    Qutachi, Omar; Vetsch, Jolanda R; Gill, Daniel; Cox, Helen; Scurr, David J; Hofmann, Sandra; Müller, Ralph; Quirk, Robin A; Shakesheff, Kevin M; Rahman, Cheryl V

    2014-12-01

    Injectable scaffolds are of interest in the field of regenerative medicine because of their minimally invasive mode of delivery. For tissue repair applications, it is essential that such scaffolds have the mechanical properties, porosity and pore diameter to support the formation of new tissue. In the current study, porous poly(dl-lactic acid-co-glycolic acid) (PLGA) microspheres were fabricated with an average size of 84±24μm for use as injectable cell carriers. Treatment with ethanolic sodium hydroxide for 2min was observed to increase surface porosity without causing the microsphere structure to disintegrate. This surface treatment also enabled the microspheres to fuse together at 37°C to form scaffold structures. The average compressive strength of the scaffolds after 24h at 37°C was 0.9±0.1MPa, and the average Young's modulus was 9.4±1.2MPa. Scaffold porosity levels were 81.6% on average, with a mean pore diameter of 54±38μm. This study demonstrates a method for fabricating porous PLGA microspheres that form solid porous scaffolds at body temperature, creating an injectable system capable of supporting NIH-3T3 cell attachment and proliferation in vitro.

  15. Microencapsulation of curcumin in PLGA microcapsules by coaxial flow focusing

    NASA Astrophysics Data System (ADS)

    Lei, Fan; Si, Ting; Luo, Xisheng; Xu, Ronald X.

    2014-03-01

    Curcumin-loaded PLGA microcapsules are fabricated by a liquid-driving coaxial flow focusing device. In the process, a stable coaxial cone-jet configuration is formed under the action of a coflowing liquid stream and the coaxial liquid jet eventually breaks up into microcapsules because of flow instability. This process can be well controlled by adjusting the flow rates of three phases including the driving PVA water solution, the outer PLGA ethyl acetate solution and the inner curcumin propylene glycol solution. Confocal and SEM imaging methods clearly indicate the core-shell structure of the resultant microcapsules. The encapsulation rate of curcumin in PLGA is measured to be more than 70%, which is much higher than the tranditional methods such as emulsion. The size distribution of resultant microcapsules under different conditions is presented and compared. An in vitro release simulation platform is further developed to verify the feasibility and reliability of the method.

  16. Evaluation of 3D printed PCL/PLGA/β-TCP versus collagen membranes for guided bone regeneration in a beagle implant model.

    PubMed

    Won, J-Y; Park, C-Y; Bae, J-H; Ahn, G; Kim, C; Lim, D-H; Cho, D-W; Yun, W-S; Shim, J-H; Huh, J-B

    2016-10-07

    Here, we compared 3D-printed polycaprolactone/poly(lactic-co-glycolic acid)/β-tricalcium phosphate (PCL/PLGA/β-TCP) membranes with the widely used collagen membranes for guided bone regeneration (GBR) in beagle implant models. For mechanical property comparison in dry and wet conditions and cytocompatibility determination, we analyzed the rate and pattern of cell proliferation of seeded fibroblasts and preosteoblasts using the cell counting kit-8 assay and scanning electron microscopy. Osteogenic differentiation was verified using alizarin red S staining. At 8 weeks following implantation in vivo using beagle dogs, computed tomography and histological analyses were performed after sacrifice. Cell proliferation rates in vitro indicated that early cell attachment was higher in collagen than in PCL/PLGA/β-TCP membranes; however, the difference subsided by day 7. Similar outcomes were found for osteogenic differentiation, with approximately 2.5 times greater staining in collagen than PCL/PLGA/β-TCP, but without significant difference by day 14. In vivo, bone regeneration in the defect area, represented by new bone formation and bone-to-implant contact, paralleled those associated with collagen membranes. However, tensile testing revealed that whereas the PCL/PLGA/β-TCP membrane mechanical properties were conserved in both wet and dry states, the tensile property of collagen was reduced by 99% under wet conditions. Our results demonstrate in vitro and in vivo that PCL/PLGA/β-TCP membranes have similar levels of biocompatibility and bone regeneration as collagen membranes. In particular, considering that GBR is always applied to a wet environment (e.g. blood, saliva), we demonstrated that PCL/PLGA/β-TCP membranes maintained their form more reliably than collagen membranes in a wet setting, confirming their appropriateness as a GBR membrane.

  17. Entrapment of H1N1 Influenza Virus Derived Conserved Peptides in PLGA Nanoparticles Enhances T Cell Response and Vaccine Efficacy in Pigs

    PubMed Central

    Hiremath, Jagadish; Kang, Kyung-il; Xia, Ming; Elaish, Mohamed; Binjawadagi, Basavaraj; Ouyang, Kang; Dhakal, Santosh; Arcos, Jesus; Torrelles, Jordi B.; Jiang, X.; Lee, Chang Won; Renukaradhya, Gourapura J.

    2016-01-01

    Pigs are believed to be one of the important sources of emerging human and swine influenza viruses (SwIV). Influenza virus conserved peptides have the potential to elicit cross-protective immune response, but without the help of potent adjuvant and delivery system they are poorly immunogenic. Biodegradable polylactic-co-glycolic acid (PLGA) nanoparticle (PLGA-NP) based vaccine delivery system enhances cross-presentation of antigens by the professional antigen presenting cells. In this study, Norovirus P particle containing SwIV M2e (extracellular domain of the matrix protein 2) chimera and highly conserved two each of H1N1 peptides of pandemic 2009 and classical human influenza viruses were entrapped in PLGA-NPs. Influenza antibody-free pigs were vaccinated with PLGA-NPs peptides cocktail vaccine twice with or without an adjuvant, Mycobacterium vaccae whole cell lysate, intranasally as mist. Vaccinated pigs were challenged with a virulent heterologous zoonotic SwIV H1N1, and one week later euthanized and the lung samples were analyzed for the specific immune response and viral load. Clinically, pigs vaccinated with PLGA-NP peptides vaccine had no fever and flu symptoms, and the replicating challenged SwIV was undetectable in the bronchoalveolar lavage fluid. Immunologically, PLGA-NP peptides vaccination (without adjuvant) significantly increased the frequency of antigen-specific IFNγ secreting CD4 and CD8 T cells response in the lung lymphocytes, despite not boosting the antibody response both at pre- and post-challenge. In summary, our data indicated that nanoparticle-mediated delivery of conserved H1N1 influenza peptides induced the virus specific T cell response in the lungs and reduced the challenged heterologous virus load in the airways of pigs. PMID:27093541

  18. Entrapment of H1N1 Influenza Virus Derived Conserved Peptides in PLGA Nanoparticles Enhances T Cell Response and Vaccine Efficacy in Pigs.

    PubMed

    Hiremath, Jagadish; Kang, Kyung-il; Xia, Ming; Elaish, Mohamed; Binjawadagi, Basavaraj; Ouyang, Kang; Dhakal, Santosh; Arcos, Jesus; Torrelles, Jordi B; Jiang, X; Lee, Chang Won; Renukaradhya, Gourapura J

    2016-01-01

    Pigs are believed to be one of the important sources of emerging human and swine influenza viruses (SwIV). Influenza virus conserved peptides have the potential to elicit cross-protective immune response, but without the help of potent adjuvant and delivery system they are poorly immunogenic. Biodegradable polylactic-co-glycolic acid (PLGA) nanoparticle (PLGA-NP) based vaccine delivery system enhances cross-presentation of antigens by the professional antigen presenting cells. In this study, Norovirus P particle containing SwIV M2e (extracellular domain of the matrix protein 2) chimera and highly conserved two each of H1N1 peptides of pandemic 2009 and classical human influenza viruses were entrapped in PLGA-NPs. Influenza antibody-free pigs were vaccinated with PLGA-NPs peptides cocktail vaccine twice with or without an adjuvant, Mycobacterium vaccae whole cell lysate, intranasally as mist. Vaccinated pigs were challenged with a virulent heterologous zoonotic SwIV H1N1, and one week later euthanized and the lung samples were analyzed for the specific immune response and viral load. Clinically, pigs vaccinated with PLGA-NP peptides vaccine had no fever and flu symptoms, and the replicating challenged SwIV was undetectable in the bronchoalveolar lavage fluid. Immunologically, PLGA-NP peptides vaccination (without adjuvant) significantly increased the frequency of antigen-specific IFNγ secreting CD4 and CD8 T cells response in the lung lymphocytes, despite not boosting the antibody response both at pre- and post-challenge. In summary, our data indicated that nanoparticle-mediated delivery of conserved H1N1 influenza peptides induced the virus specific T cell response in the lungs and reduced the challenged heterologous virus load in the airways of pigs.

  19. Layering PLGA-based electrospun membranes and cell sheets for engineering cartilage-bone transition.

    PubMed

    Mouthuy, P-A; El-Sherbini, Y; Cui, Z; Ye, H

    2016-04-01

    It is now widely acknowledged that implants that have been designed with an effort towards reconstructing the transition between tissues might improve their functionality and integration in vivo. This paper contributes to the development of improved treatment for articular cartilage repair by exploring the potential of the combination of electrospinning technology and cell sheet engineering to create cartilage tissue. Poly(lactic-co-glycolic acid) (PLGA) was used to create the electrospun membranes. The focus being on the cartilage-bone transition, collagen type I and hydroxyapatite (HA) were also added to the scaffolds to increase the histological biocompatibility. Human mesenchymal stem cells (hMSCs) were cultured in thermoresponsive dishes to allow non-enzymatic removal of an intact cell layer after reaching confluence. The tissue constructs were created by layering electrospun membranes with sheets of hMSCs and were cultured under chondrogenic conditions for up to 21 days. High viability was found to be maintained in the multilayered construct. Under chondrogenic conditions, reverse-transcription-polymerase chain reaction (RT-PCR) and immunohistochemistry have shown high expression levels of collagen type X, a form of collagen typically found in the calcified zone of articular cartilage, suggesting an induction of chondrocyte hypertrophy in the PLGA-based scaffolds. To conclude, this paper suggests that layering electrospun scaffolds and cell sheets is an efficient approach for the engineering of tissue transitions, and in particular the cartilage-bone transition. The use of PLGA-based scaffold might be particularly useful for the bone-cartilage reconstruction, since the differentiated tissue constructs seem to show characteristics of calcified cartilage.

  20. Preparation and in vitro evaluation of thienorphine-loaded PLGA nanoparticles.

    PubMed

    Yang, Yang; Xie, Xiang Yang; Mei, Xing Guo

    2016-01-01

    Poly (d,l-lactic-co-glycolide) nanoparticles (PLGA-NPs) have attracted considerable interest as new delivery vehicles for small molecules, with the potential to overcome issue such as poor drug solubility and cell permeability. However, their negative surface charge decreases bioavailability under oral administration. Recently, cationically modified PLGA-NPs has been introduced as novel carriers for oral delivery. In this study, our aim was to introduce and evaluate the physiochemical characteristics and bioadhesion of positively charged chitosan-coated PLGA-NPs (CS-PLGA-NPs), using thienorphine as a model drug. These results indicated that both CS-PLGA-NPs and PLGA-NPs had a narrow size distribution, averaging less than 130 nm. CS-PLGA-NPs was positively charged (+42.1 ± 0.4 mV), exhibiting the cationic nature of chitosan, whereas PLGA-NPs showed a negative surface charge (-2.01 ± 0.3 mV). CS-PLGA-NPs exhibited stronger bioadhesive potency than PLGA-NPs. Furthermore, the transport of thienorphine-CS-PLGA-NPs by Caco-2 cells was higher than thienorphine-PLGA-NPs or thienorphine solution. CS-PLGA-NPs were also found to significantly enhance cellular uptake compared with PLGA-NPs on Caco-2 cells. An evaluation of cytotoxicity showed no increase in toxicity in either kind of nanoparticles during the formulation process. The study proves that CS-PLGA-NPs can be used as a vector in oral drug delivery systems for thienorphine due to its positive surface charge and bioadhesive properties.

  1. Encapsulation of Volatile Compounds in Silk Microparticles.

    PubMed

    Elia, Roberto; Guo, Jin; Budijono, Stephanie; Normand, Valery; Benczédi, Daniel; Omenetto, Fiorenzo; Kaplan, David L

    2015-07-01

    Various techniques have been employed to entrap fragrant oils within microcapsules or microparticles in the food, pharmaceutical, and chemical industries for improved stability and delivery. In the present work we describe the use of silk protein microparticles for encapsulating fragrant oils using ambient processing conditions to form an all-natural biocompatible matrix. These microparticles are stabilized via physical crosslinking, requiring no chemical agents, and are prepared with aqueous and ambient processing conditions using polyvinyl alcohol-silk emulsions. The particles were loaded with fragrant oils via direct immersion of the silk particles within an oil bath. The oil-containing microparticles were coated using alternating silk and polyethylene oxide layers to control the release of the oil from the microspheres. Particle morphology and size, oil loading capacity, release rates as well as silk-oil interactions and coating treatments were characterized. Thermal analysis demonstrated that the silk coatings can be tuned to alter both retention and release profiles of the encapsulated fragrance. These oil containing particles demonstrate the ability to adsorb and controllably release oils, suggesting a range of potential applications including cosmetic and fragrance utility.

  2. Hydrophobicity of silver surfaces with microparticle geometry

    NASA Astrophysics Data System (ADS)

    Macko, Ján; Oriňaková, Renáta; Oriňak, Andrej; Kovaľ, Karol; Kupková, Miriam; Erdélyi, Branislav; Kostecká, Zuzana; Smith, Roger M.

    2016-11-01

    The effect of the duration of the current deposition cycle and the number of current pulses on the geometry of silver microstructured surfaces and on the free surface energy, polarizability, hydrophobicity and thus adhesion force of the silver surfaces has been investigated. The changes in surface hydrophobicity were entirely dependent on the size and density of the microparticles on the surface. The results showed that formation of the silver microparticles was related to number of current pulses, while the duration of one current pulse played only a minor effect on the final surface microparticle geometry and thus on the surface tension and hydrophobicity. The conventional geometry of the silver particles has been transformed to the fractal dimension D. The surface hydrophobicity depended predominantly on the length of the dendrites not on their width. The highest silver surface hydrophobicity was observed on a surface prepared by 30 current pulses with a pulse duration of 1 s, the lowest one when deposition was performed by 10 current pulses with a duration of 0.1 s. The partial surface tension coefficients γDS and polarizability kS of the silver surfaces were calculated. Both parameters can be applied in future applications in living cells adhesion prediction and spectral method selection. Silver films with microparticle geometry showed a lower variability in final surface hydrophobicity when compared to nanostructured surfaces. The comparisons could be used to modify surfaces and to modulate human cells and bacterial adhesion on body implants, surgery instruments and clean surfaces.

  3. Aspects of Microparticle Utilization for Potentiation of Novel Vaccines: Promises and Risks

    NASA Astrophysics Data System (ADS)

    Ilyinskii, P.

    Many recombinant vaccines against novel (HIV, HCV) or ever-changing (influenza) infectious agents require the presence of adjuvants/delivery vehicles to induce strong immune responses. The necessity of their improvement led to the major effort towards development of vaccine delivery systems that are generally particulate (e.g., nano- and microparticles) and have comparable dimensions to the pathogens (viruses or bacteria). The mode of action of these adjuvants is not fully understood but implies the stimulation of the innate or antigen-specific immune responses, and/or the increase of antigen uptake or processing by antigen-presenting cells (APC). Moreover, enhancement of adjuvant activity through the use of micro- and nanoparticulate delivery systems often resulted from the synergistic effects producing immune responses stronger than those elicited by the adjuvant or delivery system alone. Among particulate adjuvants, biodegradable micro- and nanoparticles of poly(D,L-lactide-co-glycoside) (PLGA) or poly(D,L-lactide) (PLA) have been reported to enhance both humoral and cellular immune responses against an encapsulated protein antigen. Cationic and anionic polylactide co-glycolide (PLG) microparticles have been successfully used to adsorb a variety of agents, which include plasmid DNA, recombinant proteins and adjuvant active oligonucleotides and are also currently tested in several vaccine applications. Another approach envisions specific targeting of APC, especially peripheral DC and exploitation of particulate systems that are small enough for lymphatic uptake (polystyrene nanobeads). Micro- and nanoparticles offer the possibility of enhancement of their uptake by appropriate cells through manipulation of their surface properties. Still, questions regarding toxicity and molecular interaction between micro- and nano-particles and immune cells, tissues and whole organisms remain to be addressed. These risks and other possible side effects should be assessed in

  4. Degradation behavior of hydroxyapatite/poly(lactic-co-glycolic) acid nanocomposite in simulated body fluid

    SciTech Connect

    Liuyun, Jiang; Chengdong, Xiong; Lixin, Jiang; Lijuan, Xu

    2013-10-15

    Graphical abstract: In this manuscript, we initiated a systematic study to investigate the effect of HA on thermal properties, inner structure, reduction of mechanical strength, surface morphology and the surface deposit of n-HA/PLGA composite with respect to the soaking time. The results showed that n-HA played an important role in improving the degradation behavior of n-HA/PLGA composite, which can accelerate the degradation of n-HA/PLGA composite and endow it with bioactivity, after n-HA was detached from PLGA during the degradation, so that n-HA/PLGA composite may have a more promising prospect of the clinical application than pure PLGA as bone fracture internal fixation materials, and the results would be of reference significance to predict the in vivo degradation and biological properties. - Highlights: • Effect of n-HA on degradation behavior of n-HA/PLGA composite was investigated. • Degradation behaviors of n-HA/PLGA and PLGA were carried out in SBF for 6 months. • Viscosity, thermal properties, inner structure and bending strength were tested. • n-HA can accelerate the degradation and endows it with bioactivity. - Abstract: To investigate the effect of hydroxyapatite(HA) on the degradation behavior of hydroxyapatite/poly(lactic-co-glycolic) acid (HA/PLGA) nanocomposite, the degradation experiment of n-HA/PLGA composite and pure PLGA were carried out by soaking in simulated body fluid(SBF) at 37 °C for 1, 2, 4 and 6 months. The change of intrinsic viscosity, thermal properties, inner structure, bending strength reduction, surface morphology and the surface deposit of n-HA/PLGA composite and pure PLGA with respect to the soaking time were investigated by means of UbbeloHde Viscometer, differential scanning calorimeter (DSC), scanning electron microscope(SEM), electromechanical universal tester, a conventional camera and X-ray diffraction (XRD). The results showed that n-HA played an important role in improving the degradation behavior of n-HA/PLGA

  5. Development of poly(lactic-co-glycolic) acid nanoparticles-embedded hyaluronic acid-ceramide-based nanostructure for tumor-targeted drug delivery.

    PubMed

    Park, Ju-Hwan; Lee, Jae-Young; Termsarasab, Ubonvan; Yoon, In-Soo; Ko, Seung-Hak; Shim, Jae-Seong; Cho, Hyun-Jong; Kim, Dae-Duk

    2014-10-01

    A hyaluronic acid-ceramide (HACE) nanostructure embedded with docetaxel (DCT)-loaded poly(d,l-lactide-co-glycolide) (PLGA) nanoparticles (NPs) was fabricated for tumor-targeted drug delivery. NPs with a narrow size distribution and negative zeta potential were prepared by embedding DCT-loaded PLGA NPs into a HACE nanostructure (DCT/PLGA/HACE). DCT-loaded PLGA and DCT/PLGA/HACE NPs were characterized by solid-state techniques, including Fourier-transform infrared (FT-IR) spectroscopy, differential scanning calorimetry (DSC), and powder X-ray diffraction (PXRD). A sustained drug release pattern from the NPs developed was observed and negligible cytotoxicity was seen in NIH3T3 cells (normal fibroblast, CD44 receptor negative) and MDA-MB-231 cells (breast cancer cells, CD44 receptor positive). PLGA/HACE NPs containing coumarin 6, used as a fluorescent dye, exhibited improved cellular uptake efficiency, based on the HA-CD44 receptor interaction, compared to plain PLGA NPs. Cyanine 5.5 (Cy5.5)-labeled PLGA/HACE NPs were injected intravenously into a MDA-MB-231 tumor xenograft mouse model and demonstrated enhanced tumor targetability, compared with Cy5.5-PLGA NPs, according to a near-infrared fluorescence (NIRF) imaging study. Considering these experimental results, the DCT/PLGA/HACE NPs developed may be useful as a tumor-targeted drug delivery system.

  6. Clinical Relevance of Microparticles from Platelets and Megakaryocytes

    PubMed Central

    Italiano, Joseph E.; Mairuhu, Albert T.A.; Flaumenhaft, Robert

    2011-01-01

    Purpose of review Platelet microparticles were identified more than forty years ago and are the most abundant circulating microparticle subtype. Yet fundamental questions about their formation and role in human disease are just beginning to be understood at the cellular and molecular level. This review will address mechanisms of platelet microparticle generation and evaluate our current understanding of their clinical relevance. Recent findings New evidence indicates that the majority of CD41+ microparticles circulating in healthy individuals derive directly from megakaryocytes. CD41+ microparticles also form from activated platelets upon loss of cytoskeleton-membrane adhesion, which occurs in a multitude of disease states characterized by elevated platelet microparticle levels. More recent studies have demonstrated that platelet microparticles function as a transport and delivery system for bioactive molecules, participating in hemostasis and thrombosis, inflammation, malignancy infection transfer, angiogenesis, and immunity. The mechanism of platelet microparticle participation in specific disease entities such as rheumatoid arthritis has been elucidated. Summary Continued research into how platelet microparticles are generated and function as a transcellular delivery system will advance our basic understanding of microparticle physiology and may enable new strategies for treatment of select disease entities. PMID:20739880

  7. Oral Delivery of DMAB-Modified Docetaxel-Loaded PLGA-TPGS Nanoparticles for Cancer Chemotherapy

    NASA Astrophysics Data System (ADS)

    Chen, Hongbo; Zheng, Yi; Tian, Ge; Tian, Yan; Zeng, Xiaowei; Liu, Gan; Liu, Kexin; Li, Lei; Li, Zhen; Mei, Lin; Huang, Laiqiang

    2011-12-01

    Three types of nanoparticle formulation from biodegradable PLGA-TPGS random copolymer were developed in this research for oral administration of anticancer drugs, which include DMAB-modified PLGA nanoparticles, unmodified PLGA-TPGS nanoparticles and DMAB-modified PLGA-TPGS nanoparticles. Firstly, the PLGA-TPGS random copolymer was synthesized and characterized. DMAB was used to increase retention time at the cell surface, thus increasing the chances of particle uptake and improving oral drug bioavailability. Nanoparticles were found to be of spherical shape with an average particle diameter of around 250 nm. The surface charge of PLGA-TPGS nanoparticles was changed to positive after DMAB modification. The results also showed that the DMAB-modified PLGA-TPGS nanoparticles have significantly higher level of the cellular uptake than that of DMAB-modified PLGA nanoparticles and unmodified PLGA-TPGS nanoparticles. In vitro, cytotoxicity experiment showed advantages of the DMAB-modified PLGA-TPGS nanoparticle formulation over commercial Taxotere® in terms of cytotoxicity against MCF-7 cells. In conclusion, oral chemotherapy by DMAB-modified PLGA-TPGS nanoparticle formulation is an attractive and promising treatment option for patients.

  8. The preosteoblast response of electrospinning PLGA/PCL nanofibers: effects of biomimetic architecture and collagen I

    PubMed Central

    Qian, Yunzhu; Chen, Hanbang; Xu, Yang; Yang, Jianxin; Zhou, Xuefeng; Zhang, Feimin; Gu, Ning

    2016-01-01

    Constructing biomimetic structure and incorporating bioactive molecules is an effective strategy to achieve a more favorable cell response. To explore the effect of electrospinning (ES) nanofibrous architecture and collagen I (COL I)-incorporated modification on tuning osteoblast response, a resorbable membrane composed of poly(lactic-co-glycolic acid)/poly(caprolactone) (PLGA/PCL; 7:3 w/w) was developed via ES. COL I was blended into PLGA/PCL solution to prepare composite ES membrane. Notably, relatively better cell response was delivered by the bioactive ES-based membrane which was fabricated by modification of 3,4-dihydroxyphenylalanine and COL I. After investigation by field emission scanning electron microscopy, Fourier transform infrared spectroscopy, contact angle measurement, and mechanical test, polyporous three-dimensional nanofibrous structure with low tensile force and the successful integration of COL I was obtained by the ES method. Compared with traditional PLGA/PCL membrane, the surface hydrophilicity of collagen-incorporated membranes was largely enhanced. The behavior of mouse preosteoblast MC3T3-E1 cell infiltration and proliferation on membranes was studied at 24 and 48 hours. The negative control was fabricated by solvent casting. Evaluation of cell adhesion and morphology demonstrated that all the ES membranes were more favorable for promoting the cell adhesion and spreading than the casting membrane. Cell Counting Kit-8 assays revealed that biomimetic architecture, surface topography, and bioactive properties of membranes were favorable for cell growth. Analysis of β1 integrin expression level by immunofluorescence indicated that such biomimetic architecture, especially COL I-grafted surface, plays a key role in cell adhesion and proliferation. The real-time polymerase chain reaction suggested that both surface topography and bioactive properties could facilitate the cell adhesion. The combined effect of biomimetic architecture with enhanced

  9. The preosteoblast response of electrospinning PLGA/PCL nanofibers: effects of biomimetic architecture and collagen I.

    PubMed

    Qian, Yunzhu; Chen, Hanbang; Xu, Yang; Yang, Jianxin; Zhou, Xuefeng; Zhang, Feimin; Gu, Ning

    Constructing biomimetic structure and incorporating bioactive molecules is an effective strategy to achieve a more favorable cell response. To explore the effect of electrospinning (ES) nanofibrous architecture and collagen I (COL I)-incorporated modification on tuning osteoblast response, a resorbable membrane composed of poly(lactic-co-glycolic acid)/poly(caprolactone) (PLGA/PCL; 7:3 w/w) was developed via ES. COL I was blended into PLGA/PCL solution to prepare composite ES membrane. Notably, relatively better cell response was delivered by the bioactive ES-based membrane which was fabricated by modification of 3,4-dihydroxyphenylalanine and COL I. After investigation by field emission scanning electron microscopy, Fourier transform infrared spectroscopy, contact angle measurement, and mechanical test, polyporous three-dimensional nanofibrous structure with low tensile force and the successful integration of COL I was obtained by the ES method. Compared with traditional PLGA/PCL membrane, the surface hydrophilicity of collagen-incorporated membranes was largely enhanced. The behavior of mouse preosteoblast MC3T3-E1 cell infiltration and proliferation on membranes was studied at 24 and 48 hours. The negative control was fabricated by solvent casting. Evaluation of cell adhesion and morphology demonstrated that all the ES membranes were more favorable for promoting the cell adhesion and spreading than the casting membrane. Cell Counting Kit-8 assays revealed that biomimetic architecture, surface topography, and bioactive properties of membranes were favorable for cell growth. Analysis of β1 integrin expression level by immunofluorescence indicated that such biomimetic architecture, especially COL I-grafted surface, plays a key role in cell adhesion and proliferation. The real-time polymerase chain reaction suggested that both surface topography and bioactive properties could facilitate the cell adhesion. The combined effect of biomimetic architecture with enhanced

  10. Cytotoxicity and intracellular fate of PLGA and chitosan-coated PLGA nanoparticles in Madin-Darby bovine kidney (MDBK) and human colorectal adenocarcinoma (Colo 205) cells.

    PubMed

    Trif, Mihaela; Florian, Paula E; Roseanu, Anca; Moisei, Magdalena; Craciunescu, Oana; Astete, Carlos E; Sabliov, Cristina M

    2015-11-01

    Polymeric nanoparticles (NPs) are known to facilitate intracellular uptake of drugs to improve their efficacy, with minimum bioreactivity. The goal of this study was to assess cellular uptake and trafficking of PLGA NPs and chitosan (Chi)-covered PLGA NPs in Madin-Darby bovine kidney (MDBK) and human colorectal adenocarcinoma (Colo 205) cells. Both PLGA and Chi-PLGA NPs were not cytotoxic to the studied cells at concentrations up to 2500 μg/mL. The positive charge conferred by the chitosan deposition on the PLGA NPs improved NPs uptake by MDBK cells. In this cell line, Chi-PLGA NPs colocalized partially with early endosomes compartment and showed a more consistent perinuclear localization than PLGA NPs. Kinetic uptake of PLGA NPs by Colo 205 was slower than that by MDBK cells, detected only at 24 h, exceeding that of Chi-PLGA NPs. This study offers new insights on NP interaction with target cells supporting the use of NPs as novel nutraceuticals/drug delivery systems in metabolic disorders or cancer therapy. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 103A: 3599-3611, 2015.

  11. Controlled release of drug and better bioavailability using poly(lactic acid-co-glycolic acid) nanoparticles.

    PubMed

    Pandey, Sanjeev K; Patel, Dinesh K; Maurya, Akhilendra K; Thakur, Ravi; Mishra, Durga P; Vinayak, Manjula; Haldar, Chandana; Maiti, Pralay

    2016-08-01

    Tamoxifen (Tmx) embedded poly(lactic-co-glycolic acid) (PLGA) nanoparticles (PLGA-Tmx) is prepared to evaluate its better DNA cleavage potential, cytotoxicity using Dalton's lymphoma ascite (DLA) cells and MDA-MB231 breast cancer cells. PLGA-Tmx nanoparticles are prepared through emulsified nanoprecipitation technique with varying dimension of 17-30nm by changing the concentrations of polymer, emulsifier and drug. Nanoparticles dimension are measured through electron and atomic force microscopy. Interactions between tamoxifen and PLGA are verified through spectroscopic and calorimetric methods. PLGA-Tmx shows excellent DNA cleavage potential as compared to pure Tmx raising better bioavailability. In vitro cytotoxicity studies indicate that PLGA-Tmx reduces DLA cells viability up to ∼38% against ∼15% in pure Tmx. Hoechst stain is used to detect apoptotic DLA cells through fluorescence imaging of nuclear fragmentation and condensation exhibiting significant increase of apoptosis (70%) in PLGA-Tmx vis-à-vis pure drug (58%). Enhanced DNA cleavage potential, nuclear fragmentation and condensation in apoptotic cells confirm greater bioavailability of PLGA-Tmx as compared to pure Tmx in terms of receptor mediated endocytosis. Hence, the sustained release kinetics of PLGA-Tmx nanoparticles shows much better anticancer efficacy through enhanced DNA cleavage potential and nuclear fragmentation and, thereby, reveal a novel vehicle for the treatment of cancer.

  12. Interactions of PLGA nanoparticles with blood components: protein adsorption, coagulation, activation of the complement system and hemolysis studies

    NASA Astrophysics Data System (ADS)

    Fornaguera, Cristina; Calderó, Gabriela; Mitjans, Montserrat; Vinardell, Maria Pilar; Solans, Conxita; Vauthier, Christine

    2015-03-01

    The intravenous administration of poly(lactic-co-glycolic) acid (PLGA) nanoparticles has been widely reported as a promising alternative for delivery of drugs to specific cells. However, studies on their interaction with diverse blood components using different techniques are still lacking. Therefore, in the present work, the interaction of PLGA nanoparticles with blood components was described using different complementary techniques. The influence of different encapsulated compounds/functionalizing agents on these interactions was also reported. It is worth noting that all these techniques can be simply performed, without the need for highly sophisticated apparatus or skills. Moreover, their transference to industries and application of quality control could be easily performed. Serum albumin was adsorbed onto all types of tested nanoparticles. The saturation concentration was dependent on the nanoparticle size. In contrast, fibrinogen aggregation was dependent on nanoparticle surface charge. The complement activation was also influenced by the nanoparticle functionalization; the presence of a functionalizing agent increased complement activation, while the addition of an encapsulated compound only caused a slight increase. None of the nanoparticles influenced the coagulation cascade at low concentrations. However, at high concentrations, cationized nanoparticles did activate the coagulation cascade. Interactions of nanoparticles with erythrocytes did not reveal any hemolysis. Interactions of PLGA nanoparticles with blood proteins depended both on the nanoparticle properties and the protein studied. Independent of their loading/surface functionalization, PLGA nanoparticles did not influence the coagulation cascade and did not induce hemolysis of erythrocytes; they could be defined as safe concerning induction of embolization and cell lysis.The intravenous administration of poly(lactic-co-glycolic) acid (PLGA) nanoparticles has been widely reported as a promising

  13. Encapsulation of glucose oxidase within poly(ethylene glycol) methyl ether methacrylate microparticles for developing an amperometric glucose biosensor.

    PubMed

    Hervás Pérez, J P; López-Cabarcos, E; López-Ruiz, B

    2008-06-15

    Poly(ethylene glycol) methyl ether methacrylate (PEGMEM) microparticles were synthesized and glucose oxidase (GOx) was immobilized within the microparticles. An amperometric biosensor was fabricated using the microparticles with GOx as biological component. The enzyme immobilization method was optimized by investigating the influence of monomer concentration and cross-linker content used in the preparation of the microparticles in the response of the biosensor. The best analytical results were obtained with the microparticles prepared with 0.21 M PEGMEM and 0.74% cross-linking. Furthermore, we have investigated the influence on the biosensor behaviour of parameters such as working potential, pH, temperature and enzymatic load. In addition, analytical properties such as sensitivity, linear range, response time and detection limit were determined. The biosensor was used to determine glucose in human serum samples and to avoid common interferents present in human serum such as uric and ascorbic acids. A Nafion layer was deposited on the electrode surface with satisfactory results. The useful lifetime of the biosensor was at least 520 days.

  14. Colonic gene silencing using siRNA-loaded calcium phosphate/PLGA nanoparticles ameliorates intestinal inflammation in vivo.

    PubMed

    Frede, Annika; Neuhaus, Bernhard; Klopfleisch, Robert; Walker, Catherine; Buer, Jan; Müller, Werner; Epple, Matthias; Westendorf, Astrid M

    2016-01-28

    Cytokines and chemokines are predominant players in the progression of inflammatory bowel diseases. While systemic neutralization of these players with antibodies works well in some patients, serious contraindications and side effects have been reported. Therefore, the local interference of cytokine signaling mediated by siRNA-loaded nanoparticles might be a promising new therapeutic approach. In this study, we produced multi-shell nanoparticles consisting of a calcium phosphate (CaP) core coated with siRNA directed against pro-inflammatory mediators, encapsulated into poly(d,l-lactide-co-glycolide acid) (PLGA), and coated with a final outer layer of polyethyleneimine (PEI), for the local therapeutic treatment of colonic inflammation. In cell culture, siRNA-loaded CaP/PLGA nanoparticles exhibited a rapid cellular uptake, almost no toxicity, and an excellent in vitro gene silencing efficiency. Importantly, intrarectal application of these nanoparticles loaded with siRNA directed against TNF-α, KC or IP-10 to mice suffering from dextran sulfate sodium (DSS)-induced colonic inflammation led to a significant decrease of the target genes in colonic biopsies and mesenteric lymph nodes which was accompanied with a distinct amelioration of intestinal inflammation. Thus, this study provides evidence that the specific and local modulation of the inflammatory response by CaP/PLGA nanoparticle-mediated siRNA delivery could be a promising approach for the treatment of intestinal inflammation.

  15. Orlistat and antisense-miRNA-loaded PLGA-PEG nanoparticles for enhanced triple negative breast cancer therapy

    PubMed Central

    Bhargava-Shah, Aarohi; Foygel, Kira; Devulapally, Rammohan; Paulmurugan, Ramasamy

    2016-01-01

    Background: This study explores the use of hydrophilic poly(ethylene glycol)-conjugated poly(lactic-co-glycolic acid) nanoparticles (PLGA-PEG-NPs) as delivery system to improve the antitumor effect of antiobesity drug orlistat for triple-negative breast cancer (TNBC) therapy by improving its bioavailability. Materials & methods: PLGA-PEG-NPs were synthesized by emulsion-diffusion-evaporation method, and the experiments were conducted in vitro in MDA-MB-231 and SKBr3 TNBC and normal breast fibroblast cells. Results: Delivery of orlistat via PLGA-PEG-NPs reduced its IC50 compared with free orlistat. Combined treatment of orlistat-loaded NPs and doxorubicin or antisense-miR-21-loaded NPs significantly enhanced apoptotic effect compared with independent doxorubicin, anti-miR-21-loaded NPs, orlistat-loaded NPs or free orlistat treatments. Conclusion: We demonstrate that orlistat in combination with antisense-miR-21 or current chemotherapy holds great promise as a novel and versatile treatment agent for TNBC. PMID:26787319

  16. Investigation and optimization of formulation parameters on preparation of targeted anti-CD205 tailored PLGA nanoparticles

    PubMed Central

    Jahan, Sheikh Tasnim; Haddadi, Azita

    2015-01-01

    The purpose of this study was to assess the effect of various formulation parameters on anti-CD205 antibody decorated poly(d, l-lactide co-glycolide) (PLGA) nanoparticles (NPs) in terms of their ability to target dendritic cells (DCs). In brief, emulsification solvent evaporation technique was adapted to design NP formulations using two different viscosity grades (low and high) of both ester and carboxylic acid terminated PLGA. Incorporation of ligand was achieved following physical adsorption or chemical conjugation processes. The physicochemical characterizations of formulations were executed to assess the effects of different solvents (chloroform and ethyl acetate), stabilizer percentage, polymer types, polymer viscosities, ligand-NP bonding types, cross-linkers, and cryoprotectants (sucrose and trehalose). Modification of any of these parameters shows significant improvement of physicochemical properties of NPs. Ethyl acetate was the solvent of choice for the formulations to ensure better emulsion formation. Infrared spectroscopy confirmed the presence of anti-CD205 antibody in the NP formulation. Finally, cytotoxicity assay confirmed the safety profile of the NPs for DCs. Thus, ligand modified structurally concealed PLGA NPs is a promising delivery tool for targeting DCs in vivo. PMID:26677326

  17. Immune responses to vaccines delivered by encapsulation into and/or adsorption onto cationic lipid-PLGA hybrid nanoparticles.

    PubMed

    Liu, Lanxia; Ma, Pingchuan; Wang, Hai; Zhang, Chao; Sun, Hongfan; Wang, Chun; Song, Cunxian; Leng, Xigang; Kong, Deling; Ma, Guilei

    2016-03-10

    In this study, we used cationic lipid-poly(lactide-co-glycolide) acid (PLGA) hybrid nanoparticles as antigen delivery carriers to investigate how antigen-loading methods affect antigen exposure to the immune system and evaluated the resulting antigen-specific immune responses. We formulated three classes of antigen adsorbed and/or encapsulated cationic lipid-PLGA hybrid nanoparticles; we designated antigen-adsorbed (out), antigen-encapsulated (in), and antigen-adsorbed/encapsulated (both) nanoparticles. Our results demonstrate significantly more efficient lysosomal escape and cross-presentation of antigen from dendritic cells (DCs) that were exposed to "both" and "in" nanoparticles. In vivo experiments further revealed that "both" nanoparticles significantly more effectively provided not only adequate initial antigen exposure but also long-term antigen persistence at the injection site. Data from flow cytometry and ELISA analyses demonstrated elevated in vivo immune responses from mice that were immunized with nanoparticles-delivered OVA when compared with free OVA. In addition, "in" and "both" nanoparticles elicited significantly higher antigen-specific immune response than "out" nanoparticles and free OVA. These results suggest that the location of antigen entrapment is an important factor in modulating the immune responses of antigens delivered by nanoparticles. Overall, we propose here a promising approach for the future design of vaccines using cationic lipid-PLGA nanoparticles.

  18. Curcumin Conjugated with PLGA Potentiates Sustainability, Anti-Proliferative Activity and Apoptosis in Human Colon Carcinoma Cells

    PubMed Central

    Waghela, Bhargav N.; Sharma, Anupama; Dhumale, Suhashini; Pandey, Shashibahl M.; Pathak, Chandramani

    2015-01-01

    Curcumin, an ingredient of turmeric, exhibits a variety of biological activities such as anti-inflammatory, anti-atherosclerotic, anti-proliferative, anti-oxidant, anti-cancer and anti-metastatic. It is a highly pleiotropic molecule that inhibits cell proliferation and induces apoptosis in cancer cells. Despite its imperative biological activities, chemical instability, photo-instability and poor bioavailability limits its utilization as an effective therapeutic agent. Therefore, enhancing the bioavailability of curcumin may improve its therapeutic index for clinical setting. In the present study, we have conjugated curcumin with a biodegradable polymer Poly (D, L-lactic-co-glycolic acid) and evaluated its apoptotic potential in human colon carcinoma cells (HCT 116). The results show that curcumin-PLGA conjugate efficiently inhibits cell proliferation and cell survival in human colon carcinoma cells as compared to native curcumin. Additionally, curcumin conjugated with PLGA shows improved cellular uptake and exhibits controlled release at physiological pH as compared to native curcumin. The curcumin-PLGA conjugate efficiently activates the cascade of caspases and promotes intrinsic apoptotic signaling. Thus, the results suggest that conjugation potentiates the sustainability, anti-proliferative and apoptotic activity of curcumin. This approach could be a promising strategy to improve the therapeutic index of cancer therapy. PMID:25692854

  19. Electrically stimulated osteogenesis on Ti-PPy/PLGA constructs prepared by laser-assisted processes.

    PubMed

    Paun, Irina Alexandra; Stokker-Cheregi, Flavian; Luculescu, Catalin Romeo; Acasandrei, Adriana Maria; Ion, Valentin; Zamfirescu, Marian; Mustaciosu, Cosmin Catalin; Mihailescu, Mona; Dinescu, Maria

    2015-10-01

    This work describes a versatile laser-based protocol for fabricating micro-patterned, electrically conductive titanium-polypyrrole/poly(lactic-co-glycolic)acid (Ti-PPy/PLGA) constructs for electrically stimulated (ES) osteogenesis. Ti supports were patterned using fs laser ablation in order to create high spatial resolution microstructures meant to provide mechanical resistance and physical cues for cell growth. Matrix Assisted Pulsed Laser Evaporation (MAPLE) was used to coat the patterned Ti supports with PPy/PLGA layers acting as biocompatible surfaces having chemical and electrical properties suitable for cell differentiation and mineralization. In vitro biological assays on osteoblast-like MG63 cells showed that the constructs maintained cell viability without cytotoxicity. At 24 h after cell seeding, electrical stimulation with currents of 200 μA was applied for 4 h. This treatment was shown to promote earlier onset of osteogenesis. More specifically, the alkaline phosphatase activity of the stimulated cultures reached the maximum before that of the non-stimulated ones, i.e. controls, indicating faster cell differentiation. Moreover, mineralization was found to occur at an earlier stage in the stimulated cultures, as compared to the controls, starting with Day 6 of cell culture. At later stages, calcium levels in the stimulated cultures were higher than those in control samples by about 70%, with Ca/P ratios similar to those of natural bone. In all, the laser-based protocol emerges as an efficient alternative to existing fabrication technologies.

  20. Nerve growth factor released from a novel PLGA nerve conduit can improve axon growth

    NASA Astrophysics Data System (ADS)

    Lin, Keng-Min; Shea, Jill; Gale, Bruce K.; Sant, Himanshu; Larrabee, Patti; Agarwal, Jay

    2016-04-01

    Nerve injury can occur due to penetrating wounds, compression, traumatic stretch, and cold exposure. Despite prompt repair, outcomes are dismal. In an attempt to help resolve this challenge, in this work, a poly-lactic-co-glycolic acid (PLGA) nerve conduit with associated biodegradable drug reservoir was designed, fabricated, and tested. Unlike current nerve conduits, this device is capable of fitting various clinical scenarios by delivering different drugs without reengineering the whole system. To demonstrate the potential of this device for nerve repair, a series of experiments were performed using nerve growth factor (NGF). First, an NGF dosage curve was developed to determine the minimum NGF concentration for optimal axonal outgrowth on chick dorsal root ganglia (DRG) cells. Next, PLGA devices loaded with NGF were evaluated for sustained drug release and axon growth enhancement with the released drug. A 20 d in vitro release test was conducted and the nerve conduit showed the ability to meet and maintain the minimum NGF requirement determined previously. Bioactivity assays of the released NGF showed that drug released from the device between the 15th and 20th day could still promote axon growth (76.6-95.7 μm) in chick DRG cells, which is in the range of maximum growth. These novel drug delivery conduits show the ability to deliver NGF at a dosage that efficiently promotes ex vivo axon growth and have the potential for in vivo application to help bridge peripheral nerve gaps.

  1. Optimization of Stability, Encapsulation, Release, and Cross-Priming of Tumor Antigen-Containing PLGA Nanoparticles

    PubMed Central

    Prasad, Shashi; Cody, Virginia; Saucier-Sawyer, Jennifer K.; Fadel, Tarek R.; Edelson, Richard L.; Birchall, Martin A.

    2014-01-01

    Purpose In order to investigate Poly (lactic-co-glycolic acid) (PLGA) nanoparticles (NP) as potential vehicles for efficient tumor antigen (TA) delivery to dendritic cells (DC), this study aimed to optimize encapsulation/release kinetics before determining immunogenicity of antigen-containing NP. Methods Various techniques were used to liberate TA from cell lines. Single (gp100) and multiple (B16-tumor lysate containing gp100) antigens were encapsulated within differing molecular weight PLGA co-polymers. Differences in morphology, encapsulation/release and biologic potency were studied. Findings were adopted to encapsulate fresh tumor lysate from patients with advanced tumors and compare stimulation of tumor infiltrating lymphocytes (TIL) against that achieved by soluble lysate. Results Four cycles of freeze-thaw + 15 s sonication resulted in antigen-rich lysates without the need for toxic detergents or protease inhibitors. The 80KDa polymer resulted in maximal release of payload and favorable production of immunostimulatory IL-2 and IFN-γ. NP-mediated antigen delivery led to increased IFN-γ and decreased immunoinhibitory IL-10 synthesis when compared to soluble lysate. Conclusions Four cycles of freeze-thaw followed by 15 s sonication is the ideal technique to obtain complex TA for encapsulation. The 80KDa polymer has the most promising combination of release kinetics and biologic potency. Encapsulated antigens are immunogenic and evoke favorable TIL-mediated anti-tumor responses. PMID:22798259

  2. Fe3O4-based PLGA nanoparticles as MR contrast agents for the detection of thrombosis

    PubMed Central

    Liu, Jia; Xu, Jie; Zhou, Jun; Zhang, Yu; Guo, Dajing; Wang, Zhigang

    2017-01-01

    Thrombotic disease is a great threat to human health, and early detection is particularly important. Magnetic resonance (MR) molecular imaging provides noninvasive imaging with the potential for early disease diagnosis. In this study, we developed Fe3O4-based poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NPs) surface-modified with a cyclic Arg-Gly-Asp (cRGD) peptide as an MR contrast agent for the detection of thrombosis. The physical and chemical characteristics, biological toxicity, ability to target thrombi, and biodistribution of the NPs were studied. The Fe3O4-PLGA-cRGD NPs were constructed successfully, and hematologic and pathologic assays indicated no in vivo toxicity of the NPs. In a rat model of FeCl3-induced abdominal aorta thrombosis, the NPs readily and selectively accumulated on the surface of the thrombosis and under vascular endothelial cells ex vivo and in vivo. In the in vivo experiment, the biodistribution of the NPs suggested that the NPs might be internalized by the macrophages of the reticuloendothelial system in the liver and the spleen. The T2 signal decreased at the mural thrombus 10 min after injection and then gradually increased until 50 min. These results suggest that the NPs are suitable for in vivo molecular imaging of thrombosis under high shear stress conditions and represent a very promising MR contrast agent for sensitive and specific detection of thrombosis. PMID:28223802

  3. Passively Targeted Curcumin-Loaded PEGylated PLGA Nanocapsules for Colon Cancer Therapy In Vivo

    PubMed Central

    Klippstein, Rebecca; Wang, Julie Tzu-Wen; El-Gogary, Riham I; Bai, Jie; Mustafa, Falisa; Rubio, Noelia; Bansal, Sukhvinder; Al-Jamal, Wafa T; Al-Jamal, Khuloud T

    2015-01-01

    Clinical applications of curcumin for the treatment of cancer and other chronic diseases have been mainly hindered by its short biological half-life and poor water solubility. Nanotechnology-based drug delivery systems have the potential to enhance the efficacy of poorly soluble drugs for systemic delivery. This study proposes the use of poly(lactic-co-glycolic acid) (PLGA)-based polymeric oil-cored nanocapsules (NCs) for curcumin loading and delivery to colon cancer in mice after systemic injection. Formulations of different oil compositions are prepared and characterized for their curcumin loading, physico-chemical properties, and shelf-life stability. The results indicate that castor oil-cored PLGA-based NC achieves high drug loading efficiency (≈18% w(drug)/w(polymer)%) compared to previously reported NCs. Curcumin-loaded NCs internalize more efficiently in CT26 cells than the free drug, and exert therapeutic activity in vitro, leading to apoptosis and blocking the cell cycle. In addition, the formulated NC exhibits an extended blood circulation profile compared to the non-PEGylated NC, and accumulates in the subcutaneous CT26-tumors in mice, after systemic administration. The results are confirmed by optical and single photon emission computed tomography/computed tomography (SPECT/CT) imaging. In vivo growth delay studies are performed, and significantly smaller tumor volumes are achieved compared to empty NC injected animals. This study shows the great potential of the formulated NC for treating colon cancer. PMID:26140363

  4. The inclusion into PLGA nanoparticles enables α-bisabolol to efficiently inhibit the human dendritic cell pro-inflammatory activity

    NASA Astrophysics Data System (ADS)

    Marongiu, Laura; Donini, Marta; Bovi, Michele; Perduca, Massimiliano; Vivian, Federico; Romeo, Alessandro; Mariotto, Sofia; Monaco, Hugo L.; Dusi, Stefano

    2014-08-01

    α-bisabolol, a natural sesquiterpene alcohol, has generated considerable interest for its anti-inflammatory activity. Since the mechanisms of this anti-inflammatory action remain poorly understood, we investigated whether α-bisabolol affects the release of pro-inflammatory cytokines IL-12, IL-23, IL-6, and TNFα by human dendritic cells (DCs). We found that α-bisabolol did not induce the secretion of these cytokines and did not affect their release induced upon DC challenge with lipopolysaccharide (LPS), a well-known immune cell stimulator. As α-bisabolol is scarcely ingested by the cells, we wondered whether the inclusion of α-bisabolol into nanoparticles could favor its internalization by DCs and consequently its effects on cytokine secretion. We then prepared and characterized poly(lactic-co-glycolic acid) (PLGA) nanoparticles, with a dynamic light scattering peak centered at 154 nm and a half width at half maximum of about 48 nm. These particles were unable to affect per se cytokine secretion by both resting and LPS-stimulated DCs and were internalized by human DCs as demonstrated by confocal microscopy analysis. We then loaded PLGA nanoparticles with α-bisabolol and we observed that PLGA-associated α-bisabolol did not stimulate the cytokine release by resting DCs, but decreased IL-12, IL-23, IL-6, and TNFα secretion by LPS-stimulated DCs. Our results indicate that α-bisabolol inclusion into PLGA nanoparticles represents a very promising tool for designing new anti-inflammatory, anti-pyretic and, possibly, immunosuppressive therapeutic strategies.

  5. MAPs/bFGF-PLGA microsphere composite-coated titanium surfaces promote increased adhesion and proliferation of fibroblasts.

    PubMed

    Wang, Zhongshan; Wu, Guofeng; Bai, Shizhu; Feng, Zhihong; Dong, Yan; Zhou, Jian; Qin, Haiyan; Zhao, Yimin

    2014-06-01

    Infection and epithelial downgrowth are two major problems with maxillofacial transcutaneous implants, and both are mainly due to lack of stable closure of soft tissues at transcutaneous sites. Fibroblasts have been shown to play a key role in the formation of biological seals. In this work, titanium (Ti) model surfaces were coated with mussel adhesive proteins (MAPs) utilizing its unique adhesion ability on diverse inorganic and organic surfaces in wet environments. Prepared basic fibroblast growth factor (bFGF)-poly(lactic-co-glycolic acid) (PLGA) microspheres can be easily synthesized and combined onto MAPs-coated Ti surfaces, due to the negative surface charges of microspheres in aqueous solution, which is in contrast to the positive charges of MAPs. Titanium model surfaces were divided into three groups. Group A: MAPs/bFGF-PLGA microspheres composite-coated Ti surfaces. Group B: MAPs-coated Ti surfaces. Group C: uncoated Ti surfaces. The effects of coated Ti surfaces on adhesion of fibroblasts, cytoskeletal organization, proliferation, and extracellular matrix (ECM)-related gene expressions were examined. The results revealed increased adhesion (P < 0.05), enhanced actin cytoskeletal organization, and up-regulated ECM-related gene expressions in groups A and B compared with group C. Increased proliferation of fibroblasts during five days of incubation was observed in group A compared with groups B and C (P < 0.05). Collectively, the results from this in vitro study demonstrated that MAPs/bFGF-PLGA microspheres composite-coated Ti surfaces had the ability to increase fibroblast functionality. In addition, MAPs/bFGF-PLGA microsphere composite-coated Ti surfaces should be studied further as a method of promoting formation of stable biological seals around transcutaneous sites.

  6. Nerve guidance conduit with a hybrid structure of a PLGA microfibrous bundle wrapped in a micro/nanostructured membrane.

    PubMed

    Peng, Shih-Wen; Li, Ching-Wen; Chiu, Ing-Ming; Wang, Gou-Jen

    2017-01-01

    Nerve repair in tissue engineering involves the precise construction of a scaffold to guide nerve cell regeneration in the desired direction. However, improvements are needed to facilitate the cell migration/growth rate of nerves in the center of a nerve conduit. In this paper, we propose a nerve guidance conduit with a hybrid structure comprising a microfibrous poly(lactic-co-glycolic acid) (PLGA) bundle wrapped in a micro/nanostructured PLGA membrane. We applied sequential fabrication processes, including photolithography, nano-electroforming, and polydimethylsiloxane casting to manufacture master molds for the repeated production of the PLGA subelements. After demolding it from the master molds, we rolled the microfibrous membrane into a bundle and then wrapped it in the micro/nanostructured membrane to form a nerve-guiding conduit. We used KT98/F1B-GFP cells to estimate the migration rate and guidance ability of the fabricated nerve conduit and found that both elements increased the migration rate 1.6-fold compared with a flat PLGA membrane. We also found that 90% of the cells in the hybrid nano/microstructured membrane grew in the direction of the designed patterns. After 3 days of culturing, the interior of the nerve conduit was filled with cells, and the microfiber bundle was also surrounded by cells. Our conduit cell culture results also demonstrate that the proposed micro/nanohybrid and microfibrous structures can retain their shapes. The proposed hybrid-structured conduit demonstrates a high capability for guiding nerve cells and promoting cell migration, and, as such, is feasible for use in clinical applications.

  7. Nerve guidance conduit with a hybrid structure of a PLGA microfibrous bundle wrapped in a micro/nanostructured membrane

    PubMed Central

    Peng, Shih-Wen; Li, Ching-Wen; Chiu, Ing-Ming; Wang, Gou-Jen

    2017-01-01

    Nerve repair in tissue engineering involves the precise construction of a scaffold to guide nerve cell regeneration in the desired direction. However, improvements are needed to facilitate the cell migration/growth rate of nerves in the center of a nerve conduit. In this paper, we propose a nerve guidance conduit with a hybrid structure comprising a microfibrous poly(lactic-co-glycolic acid) (PLGA) bundle wrapped in a micro/nanostructured PLGA membrane. We applied sequential fabrication processes, including photolithography, nano-electroforming, and polydimethylsiloxane casting to manufacture master molds for the repeated production of the PLGA subelements. After demolding it from the master molds, we rolled the microfibrous membrane into a bundle and then wrapped it in the micro/nanostructured membrane to form a nerve-guiding conduit. We used KT98/F1B-GFP cells to estimate the migration rate and guidance ability of the fabricated nerve conduit and found that both elements increased the migration rate 1.6-fold compared with a flat PLGA membrane. We also found that 90% of the cells in the hybrid nano/microstructured membrane grew in the direction of the designed patterns. After 3 days of culturing, the interior of the nerve conduit was filled with cells, and the microfiber bundle was also surrounded by cells. Our conduit cell culture results also demonstrate that the proposed micro/nanohybrid and microfibrous structures can retain their shapes. The proposed hybrid-structured conduit demonstrates a high capability for guiding nerve cells and promoting cell migration, and, as such, is feasible for use in clinical applications. PMID:28138239

  8. Convection-Enhanced Delivery of Carboplatin PLGA Nanoparticles for the Treatment of Glioblastoma.

    PubMed

    Arshad, Azeem; Yang, Bin; Bienemann, Alison S; Barua, Neil U; Wyatt, Marcella J; Woolley, Max; Johnson, Dave E; Edler, Karen J; Gill, Steven S

    2015-01-01

    We currently use Convection-Enhanced Delivery (CED) of the platinum-based drug, carboplatin as a novel treatment strategy for high grade glioblastoma in adults and children. Although initial results show promise, carboplatin is not specifically toxic to tumour cells and has been associated with neurotoxicity at high infused concentrations in pre-clinical studies. Our treatment strategy requires intermittent infusions due to rapid clearance of carboplatin from the brain. In this study, carboplatin was encapsulated in lactic acid-glycolic acid copolymer (PLGA) to develop a novel drug delivery system. Neuronal and tumour cytotoxicity were assessed in primary neuronal and glioblastoma cell cultures. Distribution, tissue clearance and toxicity of carboplatin nanoparticles following CED was assessed in rat and porcine models. Carboplatin nanoparticles conferred greater tumour cytotoxicity, reduced neuronal toxicity and prolonged tissue half-life. In conclusion, this drug delivery system has the potential to improve the prognosis for patients with glioblastomas.

  9. Cellulose acetate butyrate microparticles for controlled release of carbamazepine.

    PubMed

    Arnaud, P; Boué, C; Chaumeil, J C

    1996-01-01

    Cellulose acetate butyrate microparticles loaded in carbamazepine were prepared by a solvent evaporation technique. A decrease of the amount of organic solvent (from 80 to 40 ml of methylene chloride) increased the microparticle average diameter (73-111 and 207 microns) and decreased the carbamazepine release rate (T50% increased from 3.3 to 16.8 and 166.4 min). The microparticle area under the curve at 120 min was similar to that obtained with Tegretol LP 200 tablets.

  10. Encapsulation of poorly soluble basic drugs into enteric microparticles: a novel approach to enhance their oral bioavailability.

    PubMed

    Alhnan, Mohamed A; Murdan, Sudaxshina; Basit, Abdul W

    2011-09-15

    Poorly water soluble basic drugs are very sensitive to pH changes and following dissolution in the acidic stomach environment tend to precipitate upon gastric emptying, which leads to compromised or erratic oral bioavailability. In this work, we show that the oral bioavailability of a model poorly soluble basic drug (cinnarizine) can be improved by drug encapsulation within highly pH-responsive microparticles (Eudragit L). The latter was prepared by emulsion solvent evaporation which yielded discrete spherical microparticles (diameter of 56.4±6.8μm and a span of 1.2±0.3). These Eudragit L (dissolution threshold pH 6.0) microparticles are expected to dissolve and release their drug load at intestinal conditions. Thus, the enteric microparticles inhibited the in vitro release of drug under gastric conditions, despite high cinnarizine solubility in the acidic medium. At intestinal conditions, the particles dissolved rapidly and released the drug which precipitated out in the dissolution vessel. In contrast, cinnarizine powder showed rapid drug dissolution at low pH, followed by precipitation upon pH change. Oral dosing in rats resulted in a greater than double bioavailability of Eudragit L microparticles compared to the drug powder suspension, although C(max) and T(max) were similar. The higher bioavailability with microparticles contradicts the in vitro results. Such an example highlights that although in vitro results are an indispensable tool for formulation development, an early in vivo assessment of formulation behaviour can provide better prediction for oral bioavailability.

  11. Improvement of islet engrafts by enhanced angiogenesis and microparticle-mediated oxygenation.

    PubMed

    Montazeri, Leila; Hojjati-Emami, Shahriar; Bonakdar, Shahin; Tahamtani, Yaser; Hajizadeh-Saffar, Ensiyeh; Noori-Keshtkar, Marjan; Najar-Asl, Mostafa; Ashtiani, Mohammad Kazemi; Baharvand, Hossein

    2016-05-01

    A major hindrance in islet transplantation as a feasible therapeutic approach for patients with type 1 diabetes is the insufficient oxygenation of the grafts, which results in cell death in portions of the implant. Here we address this limitation through the application of oxygen-generating microparticles (MP) and a fibrin-conjugated heparin/VEGF collagen scaffold to support cell survival by using a β cell line and pancreatic rat islets. MP are composed of a polyvinylpyrrolidone/hydrogen peroxide (PVP/H2O2) core and poly(D,L-lactide-co-glycolide) (PLGA) shell, along with immobilized catalase on the shell. The presence of MP is sufficient to reduce hypoxia-induced cell dysfunction and death for both cell types, resulting in localization of hypoxia-inducible factor (HIF-1α) into the cytoplasm and enhanced metabolic function. After co-transplantation of MP and a reduced islet mass (250 islet equivalents) within an angiogenic scaffold in the omental pouch of streptozotocin-induced diabetic nude mice, we have observed significantly promoted graft function as evidenced by improved blood glucose levels, body weight, glucose tolerance, serum C-peptide, and graft revascularization. These results suggest that the developed platform has great potential to enhance the efficacy for implants in cases where the cell dosage is critical for efficacy, such as islet transplantation and ischemic tissues.

  12. Magnetic and fluorescence-encoded polystyrene microparticles for cell separation

    NASA Astrophysics Data System (ADS)

    Bradbury, Diana; Anglin, Emily J.; Bailey, Sheree; Macardle, Peter J.; Fenech, Michael; Thissen, Helmut; Voelcker, Nicolas H.

    2008-12-01

    Materials assisting with the efforts of cell isolation are attractive for numerous biomedical applications including tissue engineering and cell therapy. Here, we have developed surface modification methods on microparticles for the purposes of advanced cell separation. Iron oxide nanoparticles were incorporated into 200 ım polystyrene microparticles for separation of particle-bound cells from non-bound cells in suspension by means of a permanent magnet. The polystyrene microparticles were further encoded with fluorescent quantum dots (QD) as identification tags to distinguish between specific microparticles in a mixture. Cluster of differentiation (CD) antibodies were displayed on the surface of the microparticles through direct adsorption and various methods of covalent attachment. In addition, a protein A coating was used to orientate the antibodies on the microparticle surface and to maximise accessibility of the antigen-binding sites. Microparticles which carried CD antibodies via covalent attachment showed greater cell attachment over those modifications that were only adsorbed to the surface through weak electrostatic interactions. Greatest extent of cell attachment was observed on microparticles modified with protein A - CD antibody conjugates. B and T lymphocytes were successfully isolated from a mixed population using two types of microparticles displaying B and T cell specific CD antibodies, respectively. Our approach will find application in preparative cell separation from tissue isolates and for microcarrier-based cell expansion.

  13. Collagen-coated microparticles in drug delivery.

    PubMed

    Sehgal, Praveen Kumar; Srinivasan, Aishwarya

    2009-07-01

    Advantages of drug-incorporated collagen particles have been described for the controlled delivery system for therapeutic actions. The attractiveness of collagen lies in its low immunogenicity and high biocompatibility. It is also recognized by the body as a natural constituent rather than a foreign body. Our research and development efforts are focused towards addressing some of the limitations of collagen, like the high viscosity of an aqueous phase, nondissolution in neutral pH buffers, thermal instability (denaturation) and biodegradability, to make it an ideal material for drug delivery with particular reference to microparticles. These limitations could be overcome by making collagen conjugates with other biomaterials or chemically modifying collagen monomer without affecting its triple helical conformation and maintaining its native properties. This article highlights collagen microparticles' present status as a carrier in drug delivery.

  14. Adsorption of monoclonal antibodies to glass microparticles.

    PubMed

    Hoehne, Matthew; Samuel, Fauna; Dong, Aichun; Wurth, Christine; Mahler, Hanns-Christian; Carpenter, John F; Randolph, Theodore W

    2011-01-01

    Microparticulate glass represents a potential contamination to protein formulations that may occur as a result of processing conditions or glass types. The effect of added microparticulate glass to formulations of three humanized antibodies was tested. Under the three formulation conditions tested, all three antibodies adsorbed irreversibly at near monolayer surface coverages to the glass microparticles. Analysis of the secondary structure of the adsorbed antibodies by infrared spectroscopy reveal only minor perturbations as a result of adsorption. Likewise, front-face fluorescence quenching measurements reflected minimal tertiary structural changes upon adsorption. In contrast to the minimal effects on protein structure, adsorption of protein to suspensions of glass microparticles induced significant colloidal destabilization and flocculation of the suspension.

  15. Therapeutic Strategies Based on Polymeric Microparticles

    PubMed Central

    Vilos, C.; Velasquez, L. A.

    2012-01-01

    The development of the field of materials science, the ability to perform multidisciplinary scientific work, and the need for novel administration technologies that maximize therapeutic effects and minimize adverse reactions to readily available drugs have led to the development of delivery systems based on microencapsulation, which has taken one step closer to the target of personalized medicine. Drug delivery systems based on polymeric microparticles are generating a strong impact on preclinical and clinical drug development and have reached a broad development in different fields supporting a critical role in the near future of medical practice. This paper presents the foundations of polymeric microparticles based on their formulation, mechanisms of drug release and some of their innovative therapeutic strategies to board multiple diseases. PMID:22665988

  16. Comparison of intracellular accumulation and cytotoxicity of free mTHPC and mTHPC-loaded PLGA nanoparticles in human colon carcinoma cells

    NASA Astrophysics Data System (ADS)

    Löw, Karin; Knobloch, Thomas; Wagner, Sylvia; Wiehe, Arno; Engel, Andrea; Langer, Klaus; von Briesen, Hagen

    2011-06-01

    The second generation photosensitizer mTHPC was approved by the European Medicines Agency (EMA) for the palliative treatment of advanced head and neck cancer in October 2001. It is known that mTHPC possesses a significant phototoxicity against a variety of human cancer cells in vitro but also exhibits dark toxicity and can cause adverse effects (especially skin photosensitization). Due to its poor water solubility, the administration of hydrophobic photosensitizer still presents several difficulties. To overcome the administration problems, the use of nanoparticles as drug carrier systems is much investigated. Nanoparticles based on poly(lactic-co-glycolic acid) (PLGA) have been extensively studied as delivery systems into tumours due to their biocompatibility and biodegradability. The goal of this study was the comparison of free mTHPC and mTHPC-loaded PLGA nanoparticles concerning cytotoxicity and intracellular accumulation in human colon carcinoma cells (HT29). The nanoparticles delivered the photosensitizer to the colon carcinoma cells and enabled drug release without losing its activity. The cytotoxicity assays showed a time- and concentration-dependent decrease in cell proliferation and viability after illumination. However, first and foremost mTHPC lost its dark toxic effects using the PLGA nanoparticles as a drug carrier system. Therefore, PLGA nanoparticles are a promising drug carrier system for the hydrophobic photosensitizer mTHPC.

  17. Development of sulfadiazine-decorated PLGA nanoparticles loaded with 5-fluorouracil and cell viability.

    PubMed

    Guimarães, Pedro Pires Goulart; Oliveira, Sheila Rodrigues; de Castro Rodrigues, Gabrielle; Gontijo, Savio Morato Lacerda; Lula, Ivana Silva; Cortés, Maria Esperanza; Denadai, Ângelo Márcio Leite; Sinisterra, Rubén Dario

    2015-01-08

    The aim of this work was to synthesize sulfadiazine-poly(lactide-co-glycolide) (SUL-PLGA) nanoparticles (NPs) for the efficient delivery of 5-fluorouracil to cancer cells. The SUL-PLGA conjugation was assessed using FTIR, 1H-NMR, 13C-NMR, elemental analysis and TG and DTA analysis. The SUL-PLGA NPs were characterized using transmission and scanning electron microscopy and dynamic light scattering. Additionally, the zeta potential, drug content, and in vitro 5-FU release were evaluated. We found that for the SUL-PLGA NPs, Dh = 114.0 nm, ZP = -32.1 mV and the encapsulation efficiency was 49%. The 5-FU was released for up to 7 days from the NPs. Cytotoxicity evaluations of 5-FU-loaded NPs (5-FU-SUL-PLGA and 5-FU-PLGA) on two cancer cell lines (Caco-2, A431) and two normal cell lines (fibroblast, osteoblast) were compared. Higher cytotoxicity of 5-FU-SUL-PLGA NPs were found to both cancer cell lines when compared to normal cell lines, demonstrating that the presence of SUL could significantly enhance the cytotoxicity of the 5-FU-SUL-PLGA NPs when compared with 5-FU-PLGA NPs. Thus, the development of 5-FU-SUL-PLGA NPs to cancer cells is a promising strategy for the 5-FU antitumor formulation in the future.

  18. Effects of PLGA reinforcement methods on the mechanical property of carbonate apatite foam.

    PubMed

    Munar, Girlie M; Munar, Melvin L; Tsuru, Kanji; Ishikawa, Kunio

    2014-01-01

    The purpose of this study was to improve the mechanical property of brittle carbonate apatite (CO3Ap) foam aimed as bone substitute material by reinforcement with poly(DL-lactide-co-glycolide) (PLGA). The CO3Ap foam was reinforced with PLGA by immersion and vacuum infiltration methods. Compressive strength of CO3Ap foam (12.0±4.9 kPa) increased after PLGA reinforcement by immersion (187.6±57.6 kPa) or vacuum infiltration (407.0±111.4 kPa). Scanning electron microscopic (SEM) observation showed a gapless PLGA and CO3Ap foam interface and larger amount of PLGA inside the hollow space of the strut when vacuum infiltration method was employed. In contrast a gap was observed at the PLGA and CO3Ap foam interface and less amount of PLGA inside the hollow space of the strut when immersion method was employed. Strong PLGA-CO3Ap foam interface and larger amount of PLGA inside the hollow space of the strut is therefore the key to higher mechanical property obtained for CO3Ap foam when vacuum infiltration was employed for PLGA reinforcement.

  19. Preparation and properties of PLGA nanofiber membranes reinforced with cellulose nanocrystals.

    PubMed

    Mo, Yunfei; Guo, Rui; Liu, Jianghui; Lan, Yong; Zhang, Yi; Xue, Wei; Zhang, Yuanming

    2015-08-01

    Although extensively used in the fields of drug-carrier and tissue engineering, the biocompatibility and mechanical properties of polylactide-polyglycolide (PLGA) nanofiber membranes still limit their applications. The objective of this study was to improve their utility by introducing cellulose nanocrystals (CNCs) into PLGA nanofiber membranes. PLGA and PLGA/CNC composite nanofiber membranes were prepared via electrospinning, and the morphology and thermodynamic and mechanical properties of these nanofiber membranes were characterized by scanning electron microscopy (SEM), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and dynamic mechanical analysis (DMA). The cytocompatibility and cellular responses of the nanofiber membranes were also studied by WST-1 assay, SEM, and confocal laser scanning microscopy (CLSM). Incorporation of CNCs (1, 3, 5, and 7 wt.%) increased the average fiber diameter of the prepared nanofiber membranes from 100 nm (neat PLGA) to ∼400 nm (PLGA/7 wt.% CNC) and improved the thermal stability of the nanofiber membranes. Among the PLGA/CNC composite nanofiber membranes, those loaded with 7 wt.% CNC nanofiber membranes had the best mechanical properties, which were similar to those of human skin. Cell culture results showed that the PLGA/CNC composite nanofiber membranes had better cytocompatibility and facilitated fibroblast adhesion, spreading, and proliferation compared with neat PLGA nanofiber membranes. These preliminary results suggest that PLGA/CNC composite nanofiber membranes are promising new materials for the field of skin tissue engineering.

  20. Inertial Focusing of Microparticles in Curvilinear Microchannels

    NASA Astrophysics Data System (ADS)

    Özbey, Arzu; Karimzadehkhouei, Mehrdad; Akgönül, Sarp; Gozuacik, Devrim; Koşar, Ali

    2016-12-01

    A passive, continuous and size-dependent focusing technique enabled by “inertial microfluidics”, which takes advantage of hydrodynamic forces, is implemented in this study to focus microparticles. The objective is to analyse the decoupling effects of inertial forces and Dean drag forces on microparticles of different sizes in curvilinear microchannels with inner radius of 800 μm and curvature angle of 280°, which have not been considered in the literature related to inertial microfluidics. This fundamental approach gives insight into the underlying physics of particle dynamics and offers continuous, high-throughput, label-free and parallelizable size-based particle separation. Our design allows the same footprint to be occupied as straight channels, which makes parallelization possible with optical detection integration. This feature is also useful for ultrahigh-throughput applications such as flow cytometers with the advantages of reduced cost and size. The focusing behaviour of 20, 15 and 10 μm fluorescent polystyrene microparticles was examined for different channel Reynolds numbers. Lateral and vertical particle migrations and the equilibrium positions of these particles were investigated in detail, which may lead to the design of novel microfluidic devices with high efficiency and high throughput for particle separation, rapid detection and diagnosis of circulating tumour cells with reduced cost.

  1. Porphyrin Microparticles for Biological and Biomedical Applications

    NASA Astrophysics Data System (ADS)

    Huynh, Elizabeth

    Lipids are one of the critical building blocks of life, forming the plasma membrane of cells. In addition, porphyrins also play an equally important role in life, for example, through carrying oxygen in blood. The importance of both these components is evident through the biological and biomedical applications of supramolecular structures generated from lipids and porphyrins. This thesis investigates new porphyrin microparticles based on porphyrin-lipid architecture and their potential applications in biology and medicine. In Chapter 1, a background on lipid and porphyrin-based supramolecular structures is presented and design considerations for generating multifunctional agents. Chapter 2 describes the generation of a monolayer porphyrin microparticle as a dual-modal ultrasound and photoacoustic contrast agent and subsequently, a trimodal ultrasound, photoacoustic and fluorescence contrast agent. Chapter 3 examines the optical and morphological response of these multimodality ultrasound-based contrast agents to low frequency, high duty cycle ultrasound that causes the porphyrin microparticles to convertinto nanoparticles. Chapter 4 examines the generation of bilayer micrometer-sized porphyrin vesicles and their properties. Chapter 5 presents a brief summary and potential future directions. Although these microscale structures are similar in structure, the applications of these structures greatly differ with potential applications in biology and also imaging and therapy of disease. This thesis aims to explore and demonstrate the potential of new simplified, supramolecular structures based on one main building block, porphyrin-lipid.

  2. Inertial Focusing of Microparticles in Curvilinear Microchannels

    PubMed Central

    Özbey, Arzu; Karimzadehkhouei, Mehrdad; Akgönül, Sarp; Gozuacik, Devrim; Koşar, Ali

    2016-01-01

    A passive, continuous and size-dependent focusing technique enabled by “inertial microfluidics”, which takes advantage of hydrodynamic forces, is implemented in this study to focus microparticles. The objective is to analyse the decoupling effects of inertial forces and Dean drag forces on microparticles of different sizes in curvilinear microchannels with inner radius of 800 μm and curvature angle of 280°, which have not been considered in the literature related to inertial microfluidics. This fundamental approach gives insight into the underlying physics of particle dynamics and offers continuous, high-throughput, label-free and parallelizable size-based particle separation. Our design allows the same footprint to be occupied as straight channels, which makes parallelization possible with optical detection integration. This feature is also useful for ultrahigh-throughput applications such as flow cytometers with the advantages of reduced cost and size. The focusing behaviour of 20, 15 and 10 μm fluorescent polystyrene microparticles was examined for different channel Reynolds numbers. Lateral and vertical particle migrations and the equilibrium positions of these particles were investigated in detail, which may lead to the design of novel microfluidic devices with high efficiency and high throughput for particle separation, rapid detection and diagnosis of circulating tumour cells with reduced cost. PMID:27991494

  3. Preparation and characterization of mucoadhesive enteric-coating ginsenoside-loaded microparticles.

    PubMed

    Baek, Jong-Suep; Yeon, Won-Gi; Lee, Cho-A; Hwang, Sung-Joo; Park, Jeong-Sook; Kim, Dong-Chool; Cho, Cheong-Weon

    2015-01-01

    Ginsenoside saponins are phytochemically extracted from red ginseng and have been regarded as the principal components manifesting the pharmacologic activities. Saponins are very soluble in water but poorly absorbed when orally administrated. Moreover, they have some disadvantages including the decomposition in acid medium. The aim of this study was to develop oral formulation of ginsenosides composed of enteric-coating polymer and mucoadhesive polymer considering the low stability in acid medium and the low permeability of saponins. Ginsenoside-loaded microparticles were prepared by spray dryer. The influences of various parameters such as the ratio of saponin to polymer, feed concentration, feed rate, inlet/outlet temperature and additional excipients during spray-drying were investigated. In vitro release profile of ginsenoside-loaded microparticles using additional excipients, ginsenoside saponin Rg1 or Rb1 showed an 18 or 13% release in pH 1.2 when ethyl cellulose was added. Also, ginsenoside-loaded microparticles exhibited mucoadhesive properties in the presence of chitosan. The application of these polymers is being considered as the potential strategy for improvement of bioavailability in saponin delivery, orally.

  4. Bioactive insulin microparticles produced by supercritical fluid assisted atomization with an enhanced mixer.

    PubMed

    Du, Zhe; Tang, Chuan; Guan, Yi-Xin; Yao, Shan-Jing; Zhu, Zi-Qiang

    2013-09-15

    Supercritical fluid assisted atomization introduced by a hydrodynamic cavitation mixer (SAA-HCM) was used to micronize insulin from aqueous solution without use of any organic solvents. Insulin microparticles produced under different operating conditions including solution type, solution concentration and precipitator temperature presented distinct morphologies such as highly folded, partly deflated, corrugated or smooth hollow spherical shape. Solution concentration had a striking influence on particle size, and insulin microparticles produced from acidic solution had mean diameters increasing from 1.4 μm to 2.7 μm when protein concentration increased from 3g/L to 50 g/L. HPLC chromatograms showed no degradation of insulin after SAA-HCM processing and FTIR, CD and fluorescence data further confirmed the structural stability. TGA analysis revealed that insulin microparticles remained moderate moisture content compared with raw material. In vivo study showed that insulin processed by SAA-HCM from acidic solution retained identical bioactivity. SAA-HCM is demonstrated to be a very promising process for insulin inhaled formulation development.

  5. From The Cover: Poly- amino ester-containing microparticles enhance the activity of nonviral genetic vaccines

    NASA Astrophysics Data System (ADS)

    Little, Steven R.; Lynn, David M.; Ge, Qing; Anderson, Daniel G.; Puram, Sidharth V.; Chen, Jianzhu; Eisen, Herman N.; Langer, Robert

    2004-06-01

    Current nonviral genetic vaccine systems are less effective than viral vaccines, particularly in cancer systems where epitopes can be weakly immunogenic and antigen-presenting cell processing and presentation to T cells is down-regulated. A promising nonviral delivery method for genetic vaccines involves microencapsulation of antigen-encoding DNA, because such particles protect plasmid payloads and target them to phagocytic antigen-presenting cells. However, conventional microparticle formulations composed of poly lactic-co-glycolic acid take too long to release encapsulated payload and fail to induce high levels of target gene expression. Here, we describe a microparticle-based DNA delivery system composed of a degradable, pH-sensitive poly- amino ester and poly lactic-co-glycolic acid. These formulations generate an increase of 3-5 orders of magnitude in transfection efficiency and are potent activators of dendritic cells in vitro. When used as vaccines in vivo, these microparticle formulations, unlike conventional formulations, induce antigen-specific rejection of transplanted syngenic tumor cells.

  6. Evaluation of intra-articular delivery of hyaluronic acid functionalized biopolymeric nanoparticles in healthy rat knees.

    PubMed

    Zille, Hervé; Paquet, Joseph; Henrionnet, Christel; Scala-Bertola, Julien; Leonard, Michèle; Six, Jean Luc; Deschamp, Frantz; Netter, Patrick; Vergès, José; Gillet, Pierre; Grossin, Laurent

    2010-01-01

    The aim of this study is to evaluate the toxicity of nanoparticles of poly(D,L-lactic acid) (PLA) or poly(D,L-lactic-co-glycolic acid) (PLGA) covered by chemically esterified amphiphilic hyaluronate (HA) which will be used for intra-articular injection as a drug carrier for the treatment of arthritis (RA) and/or osteoarthritis (OA). PLA and PLGA are FDA approved polymers that are already used for the preparation of nano or microparticles. HA is a natural polysaccharide already present in the articulations known to interact with the CD44 receptors of the cells (especially chondrocytes). Therefore, we can envisage that the HA covering can improve the interactions between the cells and the nanoparticles, leading to better targeting or biodistribution. The knee of healthy male rats was injected one to two times weekly, with various concentrations of nanoparticles encapsulating Dextran-FITC. The synovial membranes and the patellae were collected aseptically and histologically analyzed to assess the effects and localization of the nanocapsules in the knee joint. We did not observe significant modifications in the synovial membranes (weak hyperplasia) or patellae integrity after local administration of nanodevices into the rats. While we found some nanoparticles in the synovial membrane, none were detected in the patellae. Moreover, the histological observations for patellae were confirmed by radiosulfate intake, which depicted no decrease in proteoglycans biosynthesis in nanoparticles treated animals. Concerning the safety towards synovial membranes, we also had a look at the inflammatory response after injections of nanoparticles covered by amphiphilic HA or polyvinyl alcohol (PVA) by monitoring the mRNA expression levels of some specific early cytokines (IL-1β and TNF-α). Once again, no differences were observed between the control rats and the rats treated with nanoparticles. Considering these preliminary results obtained in healthy rats, we can establish that

  7. Nanostructured hydroxyapatite/poly(lactic-co-glycolic acid) composite coating for controlling magnesium degradation in simulated body fluid

    NASA Astrophysics Data System (ADS)

    Johnson, Ian; Akari, Khalid; Liu, Huinan

    2013-09-01

    Biodegradable magnesium (Mg) and its alloys have many attractive properties (e.g. comparable mechanical properties to cortical bone) for orthopedic implant applications, but they degrade too rapidly in the human body to meet clinical requirements. Nanostructured hydroxyapatite (nHA)/poly(lactic-co-glycolic acid) (PLGA) composite coatings provide synergistic properties for controlling degradation of Mg-based substrates an