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Sample records for polymethylmethacrylate grafted chitosan

  1. Poly(methylmethacrylate) grafted chitosan: An efficient adsorbent for anionic azo dyes.

    PubMed

    Singh, V; Sharma, A K; Tripathi, D N; Sanghi, R

    2009-01-30

    Present study reports on peroxydisulfate/ascorbic acid initiated synthesis of Chitosan-graft-poly(methylmethacrylate) (Ch-g-PMMA) and its characterization by FTIR, XRD and (13)C NMR. The copolymer remained water insoluble even under highly acidic conditions and was evaluated to be an efficient adsorbent for the three anionic azo dyes (Procion Yellow MX, Remazol Brilliant Violet and Reactive Blue H5G) over a wide pH range of 4-10 being most at pH 7. The adsorbent was also found efficient in decolorizing the textile industry wastewater and was much more efficient than the parent chitosan. Equilibrium sorption experiments were carried out at different pH and initial dye concentration values. The experimental equilibrium data for each adsorbent-dye system were successfully fitted to the Langmuir and Freundlich sorption isotherms. Based on Langmuir model Q(max) for yellow, violet and blue dyes was 250, 357 and 178, respectively. Thermodynamic parameters of the adsorption processes such as DeltaG degrees , DeltaH degrees , and DeltaS degrees were calculated. The negative values of free energy reflected the spontaneous nature of adsorption. The adsorption kinetic data of all the three dyes could be well represented by pseudo-second-order model with the correlation coefficients (R(2)) being 0.9922, 0.9997 and 0.9862, for direct yellow, reactive violet and blue dye, respectively with rate constants 0.91 x 10(-4), 1.82 x 10(-4) and 1.05 x 10(-4) g mg(-1)min(-1), respectively. At pH 7, parent chitosan also showed pseudo-second-order kinetics. The temperature dependence of dye uptake and the pseudo-second-order kinetics of the adsorption indicated that chemisorption is the rate-limiting step that controls the process.

  2. Fluorescent Bioactive Corrole Grafted-Chitosan Films.

    PubMed

    Barata, Joana F B; Pinto, Ricardo J B; Vaz Serra, Vanda I R C; Silvestre, Armando J D; Trindade, Tito; Neves, Maria Graça P M S; Cavaleiro, José A S; Daina, Sara; Sadocco, Patrizia; Freire, Carmen S R

    2016-04-11

    Transparent corrole grafted-chitosan films were prepared by chemical modification of chitosan with a corrole macrocycle, namely, 5,10,15-tris(pentafluorophenyl)corrole (TPFC), followed by solvent casting. The obtained films were characterized in terms of absorption spectra (UV-vis), FLIM (fluorescence lifetime imaging microscopy), structure (FTIR, XPS), thermal stability (TGA), thermomechanical properties (DMA), and antibacterial activity. The results showed that the chemical grafting of chitosan with corrole units did not affect its film-forming ability and that the grafting yield increased with the reaction time. The obtained transparent films presented fluorescence which increases with the amount of grafted corrole units. Additionally, all films showed bacteriostatic effect against S. aureus, as well as good thermomechanical properties and thermal stability. Considering these features, promising applications may be envisaged for these corrole-chitosan films, such as biosensors, bioimaging agents, and bioactive optical devices.

  3. Use of antibiotic-loaded polymethylmethacrylate beads for the treatment of extracavitary prosthetic vascular graft infections.

    PubMed

    Stone, Patrick A; Armstrong, Paul A; Bandyk, Dennis F; Brumberg, Robert S; Flaherty, Sarah K; Back, Martin R; Johnson, Brad L; Shames, Murray L

    2006-10-01

    This study was conducted to assess the efficacy of antibiotic-loaded polymethylmethacrylate (PMMA) beads in the management of lower extremity extracavitary prosthetic arterial graft infection. This was a retrospective review of 34 patients treated for vascular surgical site (VSS) infections involving 36 prosthetic lower extremity arterial bypasses using antibiotic-loaded PMMA beads and culture-specific parenteral antibiotics for 4 to 6 weeks. Sites of graft infection were explored, debrided, and cultured. As determined from the results of Gram's stains of VSS purulence, PMMA powder was polymerized with an antibiotic (vancomycin, daptomycin, or tobramycin/gentamicin, or a combination), molded into a chain of beads, and implanted adjacent to the infected graft after debridement and pulsed-spray antibacterial lavage. All wounds were closed primarily with planned exploration to verify sterilization before a graft preservation or in situ replacement procedure. Treatment outcomes, including wound sterilization, were analyzed based on tissue culture isolates, procedures for persistent infection, and freedom from graft infection. Cultures isolated 42 pathogens, (32 gram-positive, 9 gram-negative, 1 Candida albicans) with methicillin-resistant Staphylococcus aureus (MRSA) cultured from 16 (44%) of 36 surgical site infections. As determined from the initial operative Gram's stain or a prior culture result, vancomycin PMMA beads were implanted in 29 of 36 VSS infections at the first procedure; daptomycin (n = 4) or tobramycin (n = 3) beads were implanted in the rest. Repeat VSS exploration and culture results led to an average of 2.5 antibiotic bead replacements before definitive treatment. A sterile (no growth on tissue culture) VSS was achieved in 87% of cases before a graft preservation (n = 16) or in-situ replacement of an infected graft (n = 20) procedure. No patient deaths occurred. Early and late limb salvage was 100%. Infection recurred in 4 (11%) VSSs during a mean

  4. Highly efficient chromium(VI) adsorption with nanofibrous filter paper prepared through electrospinning chitosan/polymethylmethacrylate composite.

    PubMed

    Li, Zhengyang; Li, Tingting; An, Libao; Fu, Pengfei; Gao, Cangjian; Zhang, Zhiming

    2016-02-10

    Chitosan/polymethylmethacrylate (PMMA) composite nanofibrous membrane was prepared by electrospinning technique with a single solvent system. Characterization with Fourier transformation infrared spectroscopy (FT-IR) indicated that there was weak interaction (such as hydrogen bonds) between PMMA and chitosan. Scanning electron microscopy (SEM) measurements illustrated that the average diameter of the composite nanofibers decreased as the chitosan content was increased, while the number of nano/micrometer sized beads increased in the membrane. The composite nanofibrous membrane with chitosan:PMMA ratio of 0.3:1.0 exhibited a maximum adsorption capacity (67.0 mg g(-1)) of Cr(VI) in static adsorption, which was nearly three times higher than that of chitosan powder (22.9 mg g(-1)). The adsorption capacity of Cr(VI) via filtration became even higher, where the maximum value was 92.5 mg g(-1) at pH 3.0. Notably, most of Cr(VI) has been removed after the first filtration at all pH values (2.0-6.0) investigated in this report. The adsorption capacity of the composite nanofibrous membrane decreased slightly (17.1%) after three filtration cycles even with the solution of pH 2.0, which shall be attributed to the enhanced mechanical strength and acid fastness of the composite membrane. X-ray photoelectron spectroscopy (XPS) analysis indicated that amino groups played an important role in the adsorption of Cr(VI).

  5. pH responsive graft copolymers of chitosan.

    PubMed

    Yilmaz, Elvan; Yalinca, Zulal; Yahya, Kovan; Sirotina, Uliana

    2016-09-01

    Grafting suitable polymers onto chitosan can produce cationic or polyampholyte polymers or hydrogels that are potential smart biomedical materials. Chitosan-graft-[poly(diethylamino)ethyl methacrylate] has been prepared in three different physical forms as linear free chains in solution, chemical gels crosslinked with glutaraldehyde, and poly(diethylamino)ethyl methacrylate] grafted onto chitosan tripolyphosphate gel beads. In addition to chemical structure, the graft copolymers were characterized with respect to their dissolution and swelling behavior in aqueous solution. It has been established that solubility of the products is controlled by the grafting yield. While pH sensitive polymers, which collapse at a given pH value are obtained at lower grafting yields, hydrogels form at higher grafting yields with pH responsive swelling behavior. Glutaraldehyde crosslinked chitosan-graft-[poly(diethylamino)ethyl methacrylate] gels and chitosan tripolyphosphate gel beads grafted with poly[(diethylamino)ethyl methacrylate] exhibit pH sensitive swelling with highest equilibrium swelling capacity at pH=1.2.

  6. Degradation and compatibility behaviors of poly(glycolic acid) grafted chitosan.

    PubMed

    Zhang, Luzhong; Dou, Sufeng; Li, Yan; Yuan, Ying; Ji, Yawei; Wang, Yaling; Yang, Yumin

    2013-07-01

    The films of poly(glycolic acid) grafted chitosan were prepared without using a catalyst to improve the degradable property of chitosan. The films were characterized by Fourier transform-infrared spectroscopy and X-ray photoelectron spectroscopy (XPS). The degradation of the poly(glycolic acid) grafted chitosan films were investigated in the lysozyme solution. In vitro degradation tests revealed that the degradation rate of poly(glycolic acid) grafted chitosan films increased dramatically compared with chitosan. The degradation rate of poly(glycolic acid) grafted chitosan films gradually increased with the increasing of the molar ratio of glycolic acid to chitosan. Additionally, the poly(glycolic acid) grafted chitosan films have good biocompatibility, as demonstrated by in vitro cytotoxicity of the extraction fluids. The biocompatible and biodegradable poly(glycolic acid) grafted chitosan would be an effective material with controllable degradation rate to meet the diverse needs in biomedical fields.

  7. Experimental evaluation of new chitin-chitosan graft for duraplasty.

    PubMed

    Pogorielov, M; Kravtsova, A; Reilly, G C; Deineka, V; Tetteh, G; Kalinkevich, O; Pogorielova, O; Moskalenko, R; Tkach, G

    2017-02-01

    Natural materials such as collagen and alginate have promising applications as dural graft substitutes. These materials are able to restore the dural defect and create optimal conditions for the development of connective tissue at the site of injury. A promising material for biomedical applications is chitosan-a linear polysaccharide obtained by the deacetylation of chitin. It has been found to be nontoxic, biodegradable, biofunctional and biocompatible in addition to having antimicrobial characteristics. In this study we designed new chitin-chitosan substitutes for dura mater closure and evaluated their effectiveness and safety. Chitosan films were produced from 3 % of chitosan (molar mass-200, 500 or 700 kDa, deacetylation rate 80-90%) with addition of 20% of chitin. Antimicrobial effictively and cell viability were analysed for the different molar masses of chitosan. The film containing chitosan of molar mass 200 kDa, had the best antimicrobial and biological activity and was successfully used for experimental duraplasty in an in vivo model. In conclusion the chitin-chitosan membrane designed here met the requirements for a dura matter graft exhibiting the ability to support cell growth, inhibit microbial growth and biodegradade at an appropriate rate. Therefore this is a promising material for clinical duroplasty.

  8. Surface grafted chitosan gels. Part II. Gel formation and characterization.

    PubMed

    Liu, Chao; Thormann, Esben; Claesson, Per M; Tyrode, Eric

    2014-07-29

    Responsive biomaterial hydrogels attract significant attention due to their biocompatibility and degradability. In order to make chitosan based gels, we first graft one layer of chitosan to silica, and then build a chitosan/poly(acrylic acid) multilayer using the layer-by-layer approach. After cross-linking the chitosan present in the polyelectrolyte multilayer, poly(acrylic acid) is partly removed by exposing the multilayer structure to a concentrated carbonate buffer solution at a high pH, leaving a surface-grafted cross-linked gel. Chemical cross-linking enhances the gel stability against detachment and decomposition. The chemical reaction between gluteraldehyde, the cross-linking agent, and chitosan was followed in situ using total internal reflection Raman (TIRR) spectroscopy, which provided a molecular insight into the complex reaction mechanism, as well as the means to quantify the cross-linking density. The amount of poly(acrylic acid) trapped inside the surface grafted films was found to decrease with decreasing cross-linking density, as confirmed in situ using TIRR, and ex situ by Fourier transform infrared (FTIR) measurements on dried films. The responsiveness of the chitosan-based gels with respect to pH changes was probed by quartz crystal microbalance with dissipation (QCM-D) and TIRR. Highly cross-linked gels show a small and fully reversible behavior when the solution pH is switched between pH 2.7 and 5.7. In contrast, low cross-linked gels are more responsive to pH changes, but the response is fully reversible only after the first exposure to the acidic solution, once an internal restructuring of the gel has taken place. Two distinct pKa's for both chitosan and poly(acrylic acid), were determined for the cross-linked structure using TIRR. They are associated with populations of chargeable groups displaying either a bulk like dissociation behavior or forming ionic complexes inside the hydrogel film.

  9. Transglutaminase-catalyzed grafting collagen on chitosan and its characterization.

    PubMed

    Fan, Lihong; Wu, Huan; Zhou, Xiaoyu; Peng, Min; Tong, Jun; Xie, Weiguo; Liu, Shuhua

    2014-05-25

    Collagen grafted chitosan was prepared with microbial transglutaminase (MTGase) as biocatalyst which showed high efficiency, selectivity, mild reaction condition and environmental friendliness. The reaction conditions that influenced the degree of substitution (DS) were optimized, which included the reaction time, the reaction temperature, the mass ratio of collagen to chitosan and the mass ratio of MTGase to chitosan. In this study, the water-solubility collagen-chitosan could serve not only to reduce the loss of moisture but also to absorb the moisture. And the moisture absorption and moisture retention abilities were closely related to the DS values. In addition, in vitro antioxidant activity was evaluated in terms of DS values and concentration. Furthermore, L929 mouse fibroblasts were cultured with collagen-chitosan, and methylthiazol tetrazolium (MTT) assay exhibited that collagen-chitosan with DS of 0.660 displayed pronounced cell viability at 2.5mg/ml. Therefore, the water-soluble collagen-chitosan showed the potentiality to repair skin in cosmetic, biomedical and pharmaceutical fields.

  10. Evaluating effectiveness of antibiotic polymethylmethacrylate beads in achieving wound sterilization and graft preservation in patients with early and late vascular graft infections.

    PubMed

    Poi, Mun Jye; Pisimisis, George; Barshes, Neal R; Darouiche, Rabih O; Lin, Peter H; Kougias, Panagiotis; Bechara, Carlos Fares

    2013-05-01

    The objective of the study was to evaluate the effectiveness of antibiotic-based polymethylmethacrylate (ab-PMMA) beads in achieving wound sterilization and graft preservation in patients with vascular graft infections. We reviewed 31 patients treated for 37 graft infections over the past 5 years using ab-PMMA beads in a single institution. All patients were started on broad-spectrum antibiotics and later switched to targeted therapy based on intraoperative cultures for at least 6 weeks. All patients underwent multiple planned wound explorations, debridements and washouts. Cultures were obtained each time. Decision to do formal closure depended on culture results and wound appearance. All wounds were closed with a muscle flap. The endpoints included wound sterilization, limb salvage, recurrence of infection, and graft preservation. A total of 19 different organisms were cultured, and 48.6% of cases were polymicrobial, thereby accounting for a total of 60 isolates. The majority (n = 27) received a mix of tobramycin/vancomycin PMMA beads; vancomycin beads (n = 5); tobramycin beads (n = 1); and gentamicin/vancomycin beads (n = 4). Wound sterilization based on cultures was achieved in 32 of 34 wounds (94.1%). Of the cases, 5 underwent early graft removal, 3 with immediate reconstruction, and 1 case underwent a major amputation (2.7 %). Graft preservation was attempted in 32 cases (86.5%). No death occurred within 30 days. Limb salvage was achieved in 28 of the 32 preserved graft cases (87.5%) at a mean follow-up of 26 months (6 to 51 months). The long-term limb salvage rate for the cohort was 86.5%. Of the patients, 4 presented with recurrent graft infection and occlusion, causing acute limb ischemia and resulting in major amputation. The reinfection rate was 12.5% in the graft-preservation group and 11.4% in both the graft-preserved and the in situ replacement groups. Sterilization of graft infection can be achieved with ab-PMMA beads followed by closure with muscle

  11. Controlling Properties and Cytotoxicity of Chitosan Nanocapsules by Chemical Grafting

    PubMed Central

    De Matteis, Laura; Alleva, Maria; Serrano-Sevilla, Inés; García-Embid, Sonia; Stepien, Grazyna; Moros, María; de la Fuente, Jesús M.

    2016-01-01

    The tunability of the properties of chitosan-based carriers opens new ways for the application of drugs with low water-stability or high adverse effects. In this work, the combination of a nanoemulsion with a chitosan hydrogel coating and the following poly (ethylene glycol) (PEG) grafting is proven to be a promising strategy to obtain a flexible and versatile nanocarrier with an improved stability. Thanks to chitosan amino groups, a new easy and reproducible method to obtain nanocapsule grafting with PEG has been developed in this work, allowing a very good control and tunability of the properties of nanocapsule surface. Two different PEG densities of coverage are studied and the nanocapsule systems obtained are characterized at all steps of the optimization in terms of diameter, Z potential and surface charge (amino group analysis). Results obtained are compatible with a conformation of PEG molecules laying adsorbed on nanoparticle surface after covalent linking through their amino terminal moiety. An improvement in nanocapsule stability in physiological medium is observed with the highest PEG coverage density obtained. Cytotoxicity tests also demonstrate that grafting with PEG is an effective strategy to modulate the cytotoxicity of developed nanocapsules. Such results indicate the suitability of chitosan as protective coating for future studies oriented toward drug delivery. PMID:27706041

  12. Effect of chitosan content on gel content of epoxized natural rubber grafted with chitosan in latex form.

    PubMed

    Riyajan, Sa-Ad; Sukhlaaied, Wattana

    2013-04-01

    The epoxidized natural rubber (ENR) latex-g-chitosan (ENR-g-chitosan) was prepared in latex form using potassium persulphate as an initiator. Firstly, the reduction in molecular weight of chitosan was subjected to the addition of K2S2O8 at 70 °C for 15 min. The structure of the modified chitosan was characterized by ATR-FTIR. Secondarily, the influence of chitosan contents, reaction time, and temperature and K2S2O8 concentrations on the gel content of the modified ENR was investigated. The chemical structure of the ENR-g-chitosan was confirmed by (1)H-NMR and ATR-FTIR. The ether linkage of the ENR-g-chitosan was conformed at 1154 an 1089 cm(-1) by ATR-FTIR and 3.60 ppm by (1)H-NMR. The gel content of ENR-g-chitosan at 5% chitosan showed the highest value compared with other samples. But when chitosan increased from 5% to 10% or 20%, the gel content of ENR-g-chitosan dramatically decreased. The ENR-g-chitosan showed good thermal resistance due to incorporation of chitosan. The morphology of ENR-g-chitosan particle showed the core-shell structure observed by TEM. The optimum condition of grafting ENR with chitosan was found at 65°C for 3h of reaction time, ratio of ENR/chitosan at 9:1.

  13. Preparation and characterization of catechin-grafted chitosan with antioxidant and antidiabetic potential.

    PubMed

    Zhu, Weili; Zhang, Zhanjun

    2014-09-01

    In the present study, the preparation, characterization, antioxidant and antidiabetic activities of catechin-grafted chitosan (catechin-g-chitosan) were investigated. The graft of catechin onto chitosan was achieved by redox system and confirmed using various instrumental methods. Proton nuclear magnetic resonance spectroscopy indicates that catechin has been successfully grafted onto chitosan. The morphology observation shows that chitosan changes to a softened nature with porous surface after grafting. Catechin-g-chitosan also exhibits reduced thermal stability and enhanced crystallinity compared to chitosan. Moreover, catechin-g-chitosan shows 0.51 of reducing power, 46.81% of hydroxyl radical-scavenging activity and 67.08% of DPPH radical-scavenging activity at 1mg/ml, which are much higher than that of chitosan. The antidiabetic activity in vitro assays shows that the α-glucosidase inhibitory effect decreases in the order of catechin-g-chitosan>catechin>acarbose>chitosan, and the α-amylase inhibitory effect decreases in the order of acarbose>catechin-g-chitosan>catechin>chitosan. The improved antioxidant and antidiabetic activities of catechin-g-chitosan are attributed to the phenolic groups in the catechin residues.

  14. Grafting chitosan and polyHEMA on carbon nanotubes surfaces: "grafting to" and "grafting from" methods.

    PubMed

    Mahmoodian, Hossein; Moradi, Omid; Shariatzadeh, Behnam

    2014-02-01

    We report a simple method for engineering chitosan (CS) functionalized multi-walled carbon nanotube (MWCNT) composites with a biomedically important polymer, poly-2-hydroxyethyl methacrylate (polyHEMA), by chemical grafting HEMA monomers via free radical polymerization. Functionalization of CS and polyHEMA occurred in three steps. First, using microwave irradiation, CS was grafted onto the surface and sidewall of the carbon nanotubes. Second, HEMA monomers were grafted onto the polymeric matrix surface. The final step involved free radical polymerization of HEMA monomers. Composite synthesis was confirmed by Fourier transform infrared (FTIR) spectroscopy. Moreover, the presence of polyHEMA on the surface of the CS functionalized carbon nanotubes was confirmed by field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM) and thermo gravimetric analysis (TGA) analyses. Furthermore, in the aqueous phase, our novel composites exhibited higher dispersibility compared with pristine MWCNTs. Considering the biomedical importance of polyHEMA and CS polymers, we expect these materials to be useful in the pharmaceutical industry as novel biomaterial composites with potential applications in drug delivery. Copyright © 2013 Elsevier B.V. All rights reserved.

  15. Antibacterial activity of triclosan chitosan coated graft on hernia graft infection model.

    PubMed

    Cakmak, Attila; Cirpanli, Yasemin; Bilensoy, Erem; Yorganci, Kaya; Caliş, Sema; Saribaş, Zeynep; Kaynaroğlu, Volkan

    2009-11-03

    The use of mesh in hernia repair has become common, because of lower recurrence rate and simple application. Data from the meta-analysis and the multi-central studies support the use of meshes in hernia repair. One of the complications due to the hernia repair with mesh is the infection. The incidence range is between 1 and 10%. Triclosan embedded commercial absorbable suture materials are used to reduce surgical site infection rate. This study was planned on mesh infection model, because of the low incidence rate. The agent isolated from mesh infections was mostly Staphylococcus aureus and thus it was used as the infecting agent in this research. To achieve a better therapeutic efficacy, triclosan was formulated in chitosan gels. Chitosan is an attractive biopolymer because of its biocompatible, biodegradable, bioadhesive properties. Gel formulations using chitosans (low, medium and high molecular weight) were prepared in 1% (v/v) acetic acid solution and in vitro release profiles were evaluated. Gel formulations showed release profile extended up to 7 days and high molecular weight chitosan gel formulation was released higher quantity drug than other formulations. Meshes coated with triclosan loaded chitosan gel were used to reduce bacterial count and to prevent mesh infection in the study. 24h and simultaneous bacteria inoculation was used to model mesh infection. The rats were observed for 8 days by means of surgical site infection. On the eighth day, the animals were sacrificed and the grafts were removed. Tissue squeezers were used to liberate bacterias from removed grafts. The isolated suspensions were cultured on blood agar plates and colony-forming units were counted overnight. Grafts coated with triclosan loaded chitosan gel presented satisfactory preventive effect against graft infection.

  16. Grafting of chitosan as a biopolymer onto wool fabric using anhydride bridge and its antibacterial property.

    PubMed

    Ranjbar-Mohammadi, Marziyeh; Arami, Mokhtar; Bahrami, Hajir; Mazaheri, Firoozmehr; Mahmoodi, Niyaz Mohammad

    2010-04-01

    Weak binding of chitosan on the wool constitutes the main problem in its application. In this paper, the surface modification of wool fabric using anhydrides to graft the chitosan was studied. Weight gain, antibacterial and antifelting properties of the chitosan grafted-acylated wool fabric were investigated. Wool fabrics were acylated with two anhydrides, succinic anhydride (SA) and phthalic anhydride (PA), using different solvents (dimethylsulfoxide (DMSO) and N,N-dimethyl formamide (DMF)). The effects of anhydrides, solvents, anhydride concentration, liquor ratio (L:R) and reaction time on acylation of wool were investigated. Chitosan was grafted to the acylated wool and the effects of pH, chitosan concentration, and reaction time on chitosan grafting of acylated wool were evaluated. Fourier transform infra-red (FTIR), scanning electron microscope (SEM), differential scanning colorimetry (DSC) and weight gain analyses provided evidence that chitosan was grafted on to the acylated wool through the formation of new covalent bonds. The grafted samples have antibacterial potential due to existence of the antibacterial property of chitosan. In addition, the chitosan grafted-acylated wool samples have antifelting property. The findings of this research support the potential production of new environmentally friendly textile fabrics. Copyright (c) 2009 Elsevier B.V. All rights reserved.

  17. Environmentally friendly surface modification of silk fiber: Chitosan grafting and dyeing

    NASA Astrophysics Data System (ADS)

    Davarpanah, Saideh; Mahmoodi, Niyaz Mohammad; Arami, Mokhtar; Bahrami, Hajir; Mazaheri, Firoozmehr

    2009-01-01

    In this paper, the surface modification of silk fiber using anhydrides to graft the polysaccharide chitosan and dyeing ability of the grafted silk were studied. Silk fiber was degummed and acylated with two anhydrides, succinic anhydride (SA) and phthalic anhydride (PA), in different solvents (dimethyl sulfoxide (DMSO) and N, N-dimethyl formamide (DMF)). The effects of anhydrides, solvents, anhydride concentration, liquor ratio (L:R) and reaction time on acylation of silk were studied. The polysaccharide chitosan was grafted to the acylated silk fiber and dyed by acid dye (Acid Black NB.B). The effects of pH, chitosan concentration, and reaction time on chitosan grafting of acylated silk were investigated. The physical properties show sensible changes regardless of weight gain. Scanning electron microscopy (SEM) analysis showed the presence of foreign materials firmly attached to the surface of silk. FTIR spectroscopy provided evidence that chitosan was grafted onto the acylated silk through the formation of new covalent bonds. The dyeing of the chitosan grafted-acylated silk fiber indicated the higher dye ability in comparison to the acylated and degummed silk samples. The mechanism of chitosan grafting over degummed silk through anhydride linkage was proposed. The findings of this research support the potential production of new environmentally friendly textile fibers. It is worthwhile to mention that the grafted samples have antibacterial potential due to the antibacterial property of chitosan molecules.

  18. In vivo effect of quaternized chitosan-loaded polymethylmethacrylate bone cement on methicillin-resistant Staphylococcus epidermidis infection of the tibial metaphysis in a rabbit model.

    PubMed

    Tan, Hong-Lue; Ao, Hai-Yong; Ma, Rui; Lin, Wen-Tao; Tang, Ting-Ting

    2014-10-01

    Infection of open tibial fractures with contamination remains a challenge for orthopedic surgeons. Local use of antibiotic-impregnated polymethylmethacrylate (PMMA) beads and blocks is a widely used procedure to reduce the risk of infection. However, the development of antibiotic-resistant organisms make the management of infection more difficult. Our in vitro study demonstrated that quaternized chitosan (hydroxypropyltrimethyl ammonium chloride chitosan [HACC])-loaded PMMA bone cement exhibits strong antibacterial activity toward antibiotic-resistant bacteria. Therefore, the present study aimed to investigate the in vivo antibacterial activity of quaternized chitosan-loaded PMMA. Twenty-four adult female New Zealand White rabbits were used in this study. The right proximal tibial metaphyseal cavity was prepared, 10(7) CFU of methicillin-resistant Staphylococcus epidermidis was inoculated, and PMMA-only, gentamicin-loaded PMMA (PMMA-G), chitosan-loaded PMMA (PMMA-C), or HACC-loaded PMMA (PMMA-H) bone cement cylinders were inserted. During the follow-up period, the infections were evaluated using X rays on days 21 and 42 and histopathological and microbiological analyses on day 42 after surgery. Radiographic indications of bone infections, including bone lysis, periosteal reactions, cyst formation, and sequestral bone formation, were evident in the PMMA, PMMA-G, and PMMA-C groups but not in the PMMA-H group. The radiographic scores and gross bone pathological and histopathological scores were significantly lower in the PMMA-H group than in the PMMA, PMMA-G, and PMMA-C groups (P < 0.05). Explant cultures also indicated significantly less bacterial growth in the PMMA-H group than in the PMMA, PMMA-G, and PMMA-C groups (P < 0.01). We concluded that PMMA-H bone cement can inhibit the development of bone infections in this animal model inoculated with antibiotic-resistant bacteria, thereby demonstrating its potential application for treatment of local infections in open

  19. Synthesis and characterization of membranes obtained by graft copolymerization of 2-hydroxyethyl methacrylate and acrylic acid onto chitosan.

    PubMed

    dos Santos, K S C R; Coelho, J F J; Ferreira, P; Pinto, I; Lorenzetti, S G; Ferreira, E I; Higa, O Z; Gil, M H

    2006-03-09

    Chitosan based membranes to be applied on wound healing as topical drug delivery systems were developed by graft copolymerization of acrylic acid (AA) and 2-hydroxyethyl methacrylate (HEMA) onto chitosan using cerium ammonium nitrate as chemical initiator. Evidence for graft copolymerization of the vinyl monomers onto chitosan was obtained by FTIR and DMTA. Swelling degree, cytotoxicity, thrombogenicity and haemolytic activity of these membranes were evaluated. Chitosan-graft-AA-graft-HEMA showed to be the best matrix for drug delivery systems than chitosan-graft-AA because it retains good swelling properties, but the content in HEMA has improved cytocompatibility, hemocompatibility and thrombogenic character.

  20. Grafting of Chitosan and Chitosantrimethoxylsilylpropyl Methacrylate on Single Walled Carbon Nanotubes-Synthesis and Characterization.

    PubMed

    Carson, Laura; Kelly-Brown, Cordella; Stewart, Melisa; Oki, Aderemi; Regisford, Gloria; Stone, Julia; Traisawatwong, Pasakorn; Durand-Rougely, Clarissa; Luo, Zhiping

    2010-09-01

    Acid functionalized single walled carbon nanotubes (CNTs) were grafted to chitosan by first reacting the oxidized CNTs with thionyl chloride to form acyl-chlorinated CNTs. This product was subsequently dispersed in chitosan and covalently grafted to form CNT-chitosan. CNT-chitosan was further grafted onto 3-trimethoxysilylpropyl methacrylate by free radical polymerization conditions, to yield CNT-g-chitosan-g-3-trimethoxysilylpropyl methacrylate (TMSPM), hereafter referred to as CNT-chitosan-3-TMSPM. These composites were characterized by Fourier Transform Infrared Resonance Spectroscopy (FTIR), carbon-13 nuclear magnetic resonance ((13)C NMR), Thermogravimetric Analysis (TGA), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The composite showed improved thermal stability and could be of great potential use in bone tissue engineering.

  1. Grafting of Chitosan and Chitosantrimethoxylsilylpropyl Methacrylate on Single Walled Carbon Nanotubes-Synthesis and Characterization

    PubMed Central

    Carson, Laura; Kelly-Brown, Cordella; Stewart, Melisa; Oki, Aderemi; Regisford, Gloria; Stone, Julia; Traisawatwong, Pasakorn; Durand-Rougely, Clarissa; Luo, Zhiping

    2011-01-01

    Acid functionalized single walled carbon nanotubes (CNTs) were grafted to chitosan by first reacting the oxidized CNTs with thionyl chloride to form acyl-chlorinated CNTs. This product was subsequently dispersed in chitosan and covalently grafted to form CNT-chitosan. CNT-chitosan was further grafted onto 3-trimethoxysilylpropyl methacrylate by free radical polymerization conditions, to yield CNT-g-chitosan-g-3-trimethoxysilylpropyl methacrylate (TMSPM), hereafter referred to as CNT-chitosan-3-TMSPM. These composites were characterized by Fourier Transform Infrared Resonance Spectroscopy (FTIR), carbon-13 nuclear magnetic resonance (13C NMR), Thermogravimetric Analysis (TGA), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The composite showed improved thermal stability and could be of great potential use in bone tissue engineering. PMID:21765959

  2. Water absorbency of chitosan grafted acrylic acid hydrogels

    NASA Astrophysics Data System (ADS)

    Astrini, N.; Anah, L.; Haryono, A.

    2017-07-01

    Acrylic acid (AA) monomer was directly grafted onto chitosan (CTS) using potassium persulfate (KPS) as an initiator and methylenebisacrylamide (MBA) as a crosslinking agent under an inert atmosphere. One factor affecting the swelling capacity of the obtained hydrogel, KPS concentration, were studied. The hydrogel products were characterized using Fourier Transform Infrared spectroscopy (FTIR) for chemical structure and scanning electron microscopy (SEM) for morphology. Swelling of the hydrogel samples in distilled water and saline solution ( 9% NaCl ) was examined. Swelling capacity of the CTS-g-PAA hydrogels in distilled water (88.53 g/g) was higher than in NaCl solution (29.94 g/g) The highest swelling capacity value was obtained when the grafted reaction was carried out using 2.5wt% initiator

  3. Enzymatic grafting of carboxyl groups on to chitosan--to confer on chitosan the property of a cationic dye adsorbent.

    PubMed

    Chao, An-Chong; Shyu, Shin-Shing; Lin, Yu-Chuang; Mi, Fwu-Long

    2004-01-01

    Chitosan (CTS) is a good adsorbent for dyes but lacks the ability to adsorb cationic dyes. In this study, chitosan was modified to possess the ability to adsorb cationic dyes from water. Four kinds of phenol derivatives: 4-hydroxybenzoic acid (BA), 3,4-dihydroxybenzoic acid (DBA), 3,4-dihydroxyphenyl-acetic acid (PA), hydrocaffeic acid (CA) were used individually as substrates of tyrosinase to graft onto chitosan. FTIR analysis provided supporting evidence of phenol derivatives being grafted. The grafting amounts of these phenol derivatives onto chitosan were examined by the adsorption of an anionic dye (amaranth) and reached a plateau value. The final contents of carboxyl groups in chitosan (mmol carboxyl groups per kg chitosan) were measured as 46.36 for BA, 70.32 for DBA, 106.44 for PA, and 113.15 for CA. These modified chitosans were used in experiments on uptake of the cationic dyes crystal violet (CV) and bismarck brown Y (BB) by a batch adsorption technique at pH 7 for CV and at pH 9 for BB and 30 degrees C. Langmuir type adsorption was found, and the maximum adsorption capacities for both dyes were increased with the following order CTS-CA>CTS-PA>CTS-DBA>CTS-BA.

  4. Synthesis and characterization of noncytotoxic and biodegradable polymethacrylates-grafted chitosan gels.

    PubMed

    Adalı, Terin

    2013-01-01

    Poly(methacrylates), namely 2-hydroxy ethyl methacrylate (HEMA), ethylene glycol dimethacrylate (EGDMA) and triethylene glycol dimethacrylate (TEGDMA) were grafted onto chitosan by using ceric ammonium nitrate as a redox initiator. Semi-IPN gels of chitosan-graft-poly(HEMA)-graft-poly(EGDMA) and chitosan-graft-poly(HEMA)-graft-poly(TEGDMA) were obtained. The grafting conditions were optimized with respect to monomer concentrations. The products were characterized by TGA, FTIR, XRD and SEM techniques. The solubility of the grafted products in aqueous medium decreased with increasing grafting percentage. The insoluble gels exhibited a highly pH sensitive swelling behaviour. TGA thermograms showed that poly(HEMA)/poly(TEGDMA)-grafted product is much more stable than poly(HEMA)/poly(EGDMA)-grafted product showing that TEGDMA is a more effective crosslinker than EGDMA. According to XRD analysis TEGDMA has a higher tendency to form ordered structures than EGDMA as it is capable of chain folding. The results of cytotoxicity studies revealed that the methacrylate-grafted chitosans were noncytotoxic and good candidates for biomedical applications.

  5. Investigation on dyeability of polypropylene fabrics grafted with chitosan after plasma modification

    NASA Astrophysics Data System (ADS)

    Shahidi, Sheila; Moazzenchi, Bahareh; Ghoranneviss, Mahmood; Azizi, Samar

    2013-04-01

    In this study, the properties of polypropylene fabrics grafted with chitosan after being activated by low temperature plasmas were evaluated. The chitosan was applied to polypropylene fabrics by using pad-dry cure technique. The surface morphology was characterized by SEM images. Treated samples were characterized by means of Fourier transform infrared (FTIR) spectroscopy. The polypropylene fabric treated with chitosan demonstrates an excellent dyeability property.

  6. Hydrophobic amino acids grafted onto chitosan: a novel amphiphilic chitosan nanocarrier for hydrophobic drugs.

    PubMed

    Motiei, Marjan; Kashanian, Soheila; Taherpour, Avat Arman

    2017-01-01

    The objective of this study is to develop a novel biocompatible amphiphilic drug delivery for hydrophobic drugs, chitosan (CS) was grafted to a series of hydrophobic amino acids including l-alanine (A), l-proline (P), and l-tryptophan (W) by carbodiimide mediated coupling reaction. Chemical characteristics of the modified polymers were determined and confirmed by FT-IR, (1)H NMR, and UV-vis spectroscopy and the degree of substitution was quantified by elemental analysis. The modified polymers were used to form amphiphilic chitosan nanocarriers (ACNs) by the conventional self-assembly method using ultrasound technique. The morphology and the size of ACNs were analyzed by scanning electron microscope (SEM) and Dynamic light scattering (DLS). The sizes of spherical ACNs analyzed by SEM were obviously smaller than those of determined by DLS. The ACNs effectively surrounded the hydrophobic model drug, letrozole (LTZ), and demonstrated different encapsulation efficiencies (EE), loading capacities (LC), and controlled drug release profiles. The characteristics of ACNs and the mechanism of drug encapsulation were confirmed by molecular modeling method. The modeling of the structures of LTZ, profiles of A, P, and W grafted onto CS and the wrapping process around LTZ was performed by quantum mechanics (QM) methods. There was a good agreement between the experimental and theoretical results. The cell viability was also evaluated in two cell lines compared with free drug by MTT assay. The hydrophobic portion effects on ACNs' characteristics and the proper selection of amino acid demonstrate a promising potential for drug delivery vector.

  7. The effect of solvent composition on grafting gallic acid onto chitosan via carbodiimide.

    PubMed

    Guo, Ping; Anderson, John D; Bozell, Joseph J; Zivanovic, Svetlana

    2016-04-20

    The primary antioxidant (AOX) activity of chitosan can be introduced by grafting of phenolic compound - gallic acid (GA) to its amino and/or hydroxyl groups. The objective of this study was to investigate the effect of ethanol (EtOH) concentration (0%, 25%, 50%, and 75% in water) on efficiency of grafting GA onto chitosan in the presence of 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide (EDC)/N-hydroxysuccinimide (NHS). The grafting was confirmed by FTIR and the efficiency was quantified as Folin's total phenolics. When pure deionized water was used as a sole solvent (0% EtOH), GA was grafted to chitosan at the largest extent (285.9mg GA/g chitosan). As the concentration of EtOH increased, the grafting efficiency proportionally decreased. NMR studies showed that EtOH inhibited grafting of GA by prohibiting the production of the intermediate - NHS ester. The results confirm that the concentration of EtOH in grafting solution significantly affects grafting efficiency of GA on chitosan.

  8. Study on chemical, UV and gamma radiation-induced grafting of 2-hydroxyethyl methacrylate onto chitosan

    NASA Astrophysics Data System (ADS)

    Casimiro, M. H.; Botelho, M. L.; Leal, J. P.; Gil, M. H.

    2005-04-01

    In the present study, 2-hydroxyethyl methacrylate has been grafted onto chitosan by using either chemical initiation, or photo-induction or gamma radiation-induced polymerisation, all under heterogeneous conditions. The evidence of grafting was provided by Fourier transform infrared spectroscopy and thermal analysis. The results concerning the effect of initiator concentration, initial monomer concentration and dose rate influencing on the yield of grafting reactions are presented. These suggest that gamma irradiation is the method that leads to higher yields of grafting.

  9. Flocculation of both anionic and cationic dyes in aqueous solutions by the amphoteric grafting flocculant carboxymethyl chitosan-graft-polyacrylamide.

    PubMed

    Yang, Zhen; Yang, Hu; Jiang, Ziwen; Cai, Tao; Li, Haijiang; Li, Haibo; Li, Aimin; Cheng, Rongshi

    2013-06-15

    In the current work, a series of amphoteric grafting chitosan-based flocculants (carboxymethyl chitosan-graft-polyacrylamide, denoted as CMC-g-PAM) was designed and prepared successfully. The flocculants were applied to eliminate various dyes from aqueous solutions. Among different graft copolymers, CMC-g-PAM11 with a PAM grafting ratio of 74% demonstrated the most efficient performance for removal of both the anionic dye (Methyl Orange, MO) and the cationic dye (Basic Bright Yellow, 7GL) under the corresponding favored conditions (80 mg/L of the flocculant at pH 4.0, and 160 mg/L at pH 11.0). In comparison with its precursors, chitosan and carboxymethyl chitosan, CMC-g-PAM11 showed higher removal efficiencies and wider flocculation windows. More importantly, the graft copolymer produced notably more compacted flocs based on image analysis in combination with fractal theory, which was of great significance in practical water treatment. Furthermore, the flocculation mechanism was discussed in detail. The grafted polyacrylamide chains were found to contribute much to the improved bridging and sweeping flocculation effects, but reduced charge neutralization flocculation for the effect of charge screening. Copyright © 2013 Elsevier B.V. All rights reserved.

  10. Real-time monitoring of peptide grafting onto chitosan films using capillary electrophoresis.

    PubMed

    Taylor, Danielle L; Thevarajah, Joel J; Narayan, Diksha K; Murphy, Patricia; Mangala, Melissa M; Lim, Seakcheng; Wuhrer, Richard; Lefay, Catherine; O'Connor, Michael D; Gaborieau, Marianne; Castignolles, Patrice

    2015-03-01

    Chitosan, being antimicrobial and biocompatible, is attractive as a cell growth substrate. To improve cell attachment, arginine-glycine-aspartic acid-serine (RGDS) peptides were covalently grafted to chitosan films, through the widely used coupling agents 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC-HCl) and N-hydroxysuccinimide (NHS), via the carboxylic acid function of the RGDS molecule. The grafting reaction was monitored, for the first time, in real time using free-solution capillary electrophoresis (CE). This enabled fast separation and determination of the peptide and all other reactants in one separation with no sample preparation. Covalent RGDS peptide grafting onto the chitosan film surface was demonstrated using solid-state NMR of swollen films. CE indicated that oligomers of RGDS, not simply RGDS, were grafted on the film, with a likely hyperbranched structure. To assess the functional properties of the grafted films, cell growth was compared on control and peptide-grafted chitosan films. Light microscopy and polymerase chain reaction (PCR) analysis demonstrated greatly improved cell attachment to RGDS-grafted chitosan films.

  11. Grafting of GMA and some comonomers onto chitosan for controlled release of diclofenac sodium.

    PubMed

    Sharma, Rajeev Kr; Lalita; Singh, Anirudh P; Chauhan, Ghanshyam S

    2014-03-01

    In order to develop pH sensitive hydrogels for controlled drug release we have graft copolymerized glycidyl methacrylate (GMA) with comonomers acrylic acid, acrylamide and acrylonitrile, onto chitosan (Ch) by using potassium persulphate (KPS) as free radical initiator in aqueous solution. The optimum percent grafting for GMA was recorded for 1g chitosan at [KPS]=25.00 × 10(-3)mol/L, [GMA]=0.756 × 10(-3)mol/L, reaction temperature=60 °C and reaction time=1h in 20 mL H2O. Binary monomers were grafted for five different concentrations at optimum grafting conditions evaluated for GMA alone onto chitosan. The graft copolymers were characterized by FTIR, XRD, TGA and SEM. The swelling properties of chitosan and graft copolymers were investigated at different pH to define their end uses in sustained release of an anti-inflammatory drug, diclofenac sodium. Percent drug release w.r.t. drug loaded in polymeric sample was studied as function of time in buffer solutions of pH 2.0 and 7.4. In vitro release data was analyzed using Fick's Law. Chitosan grafted with binary monomers, GMA-co-AAm and GMA-co-AN showed very good results for sustained release of drug at 7.4 pH.

  12. Zwitterionic phosphorylcholine grafted chitosan nanofiber: Preparation, characterization and in-vitro cell adhesion behavior.

    PubMed

    Oktay, Burcu; Kayaman-Apohan, Nilhan; Süleymanoğlu, Mediha; Erdem-Kuruca, Serap

    2017-04-01

    In this study, zwitterionic phosphorylcholine grafted electrospun chitosan fiber was accomplished in three steps: (1) Azide groups on the chitosan were regioselectively replaced with hydroxyl side group and then the product was electrospun. (2) Chitosan based macroinitiator was prepared using an azide-alkyne click reaction from azide-functionalized electrospun chitosan fiber. (3) Poly(2-methacryloyloxyethyl phosphorylcholine) (MPC) was grafted onto the electrospun chitosan fiber by atom transfer radical polymerization (ATRP) in order to enhance cellular viability and proliferation of 3T3, ECV and Saos. The structure of surface modified chitosan was characterized by Fourier transform infrared spectrometer (FT-IR) and (1)H nuclear magnetic resonance ((1)H NMR). The surface morphology of the nanofibers was investigated by scanning electron microscope (SEM). In-vitro cellular attachment and spreading experiments of 3T3, ECV304 and Saos were performed on electrospun chitosan fibers in the presence and the absence of MPC grafting. Poly(MPC) grafted electrospun fiber showed an excellent performance due to phosphorylcholine groups mimicking the natural phospholipid. Copyright © 2016 Elsevier B.V. All rights reserved.

  13. Synthesis of Novel Pyrimethanil Grafted Chitosan Derivatives with Enhanced Antifungal Activity

    PubMed Central

    Liu, Song; Xing, Ronge; Chen, Xiaolin

    2016-01-01

    In this study, three pyrimethanil grafted chitosan (PML-g-CS) derivatives were obtained. The structures of the conjugates were confirmed by FT-IR, 1H NMR, and EA. The grafting ratios were measured by HPLC. Antifungal properties of pyrimethanil grafted chitosan (PML-g-CS) derivatives against the plant pathogenic fungi Rhizoctonia solani and Gibberella zeae were investigated at concentrations of 100, 200, and 400 mg/L. The PML-g-CS derivatives showed enhanced antifungal activity in comparison with chitosan. The PML-g-CS-1 showed the best antifungal activity against R. solani, whose antifungal index was 58.32%. The PML-g-CS-2 showed the best antifungal activity against G. zeae, whose antifungal index was 53.48%. The conjugation of chitosan and pyrimethanil showed synergistic effect. The PML-g-CS derivatives we developed showed potential for further study and application in crop protection. PMID:27529072

  14. Argon Plasma-Induced Graft Polymerization of PEGMA on Chitosan Membrane Surface for Cell Adhesion Improvement

    NASA Astrophysics Data System (ADS)

    Yin, Shiheng; Ren, Li; Wang, Yingjun

    2013-10-01

    For its biocompatibility and biodegradability, chitosan has had considerable attention for biomedical applications in recent years. In this paper, polymerization of poly (ethylene glycol) methyl ether methacrylate (PEGMA) was grafted onto chitosan membrane surface through argon plasma-induced graft polymerization. The surface properties after modification were characterized by contact angle measurement, X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM), respectively. The results indicated that PEGMA can be grafted successfully onto chitosan membrane surface. The surface hydrophilicity and free energy were improved and the surface roughness increased after modification. The adhesion of a human corneal epithelial cell (HCEC) on chitosan membrane surface was enhanced due to improvement of surface free energy and roughness.

  15. Preparation of extruded polyethylene/chitosan blends compatibilized with polyethylene-graft-maleic anhydride.

    PubMed

    Quiroz-Castillo, J M; Rodríguez-Félix, D E; Grijalva-Monteverde, H; Del Castillo-Castro, T; Plascencia-Jatomea, M; Rodríguez-Félix, F; Herrera-Franco, P J

    2014-01-30

    Novel films of polyethylene and chitosan were obtained using extrusion. These polymers have interesting properties, and processing them with methods that are of high use in the industry, such as the extrusion method, can have a significant effect on the potential applications of these materials. The individual materials were thermally characterized; after this, extruded films of low density polyethylene and chitosan mixtures were prepared with the addition of polyethylene-graft-maleic anhydride as a compatibilizer for the blends, and glycerol, as a plasticizer for chitosan. The use of compatibilizer and plasticizer agents improved the processability and compatibility of the mixtures, as well as their mechanical properties, as revealed by mechanical property measurements and scanning electron microscopy. It was possible to prepare blends with a maximum chitosan content of 20 wt%. The material stiffness increased with the increase of chitosan in the sample. FTIR studies revealed the existence of an interaction between the compatibilizer and chitosan.

  16. Stearyl methacrylate-grafted-chitosan nanoparticle as a nanofiller for PLA: Radiation-induced grafting and characterization

    NASA Astrophysics Data System (ADS)

    Rattanawongwiboon, Thitirat; Haema, Kamonwon; Pasanphan, Wanvimol

    2014-01-01

    This paper reports a one-pot synthesis using radiation-induced grafting technique to modify biopolymer-based chitosan nanoparticles as a nanofiller for blending with poly(lactic acid) (PLA). Hydrophobic stearyl methacrylate (SMA) was grafted onto non-irradiated chitosan (CS0) and pre-irradiated chitosan with a γ-ray dose of 40 kGy (CS40) to obtain stearyl methacrylate-grafted-chitosan nanoparticles (SMA-g-CSNPs).The effects of the pre-irradiated CS, grafting doses and SMA concentrations on degree of grafting (DG) and particle formation were studied. FT-IR and XRD were used to characterize the chemical and packing structure of SMA-g-CSNPs. The particle formulation and size of SMA-g-CSNPs were observed by TEM and AFM. The spherical core-shell SMA-g-CSNPs with the size ranging from 50 to 140 nm were successfully prepared. The SMA-g-CSNPs from CS40 has higher DG and smaller particle size when compared with CS0. The SMA-g-CSNPs are able to improve the compatibility between CS and PLA.

  17. Blood compatibility of chitosan/heparin complex surface modified ePTFE vascular graft

    NASA Astrophysics Data System (ADS)

    Zhu, A. P.; Ming, Zhang; Jian, Shen

    2005-03-01

    Vascular grafts made of expanded polytetrafluoroethylene (ePTFE) are widely employed in vascular reconstructive surgery. While they are successful as replacements for large-diameter blood vessels, ePTFE vascular grafts are unsuitable for small-diameter ones because when the internal diameters of the graft are less than 6 mm, they are found to fail without exception due to blood clot formation. To reduce platelets adhesion onto the ePTFE vascular graft, a novel method of binding of chitosan/heparin (CS/Hp) complex to the surface of vascular graft was developed. The binding of chitosan was achieved by irradiating with ultraviolet light the azide modified chitosan that was coated on the ePTFE surface. By forming complex with this coating of chitosan, heparin was then bonded to the ePTFE surface. In vitro blood compatibility experiments showed that CS/Hp surface-modified ePTFE vascular grafts exhibited markedly reduced platelets adhesion. The outstanding performance of these grafts was further demonstrated by the in vivo experiments, in which they were found to be still unclogged two weeks post-implantation into dog veins.

  18. Pyridine-grafted chitosan derivative as an antifungal agent.

    PubMed

    Jia, Ruixiu; Duan, Yunfei; Fang, Qiang; Wang, Xiangyang; Huang, Jianying

    2016-04-01

    Pyridine moieties were introduced into chitosan by nucleophilic substitution to afford N-(1-carboxybutyl-4-pyridinium) chitosan chloride (pyridine chitosan). The resulting chitosan derivative was well characterized, and its antifungal activity was examined, based on the inhibition of mycelial growth and spore germination. The results indicated that pyridine chitosan exhibited enhanced antifungal activity by comparison with pristine chitosan. The values of the minimum inhibitory concentration and the minimal fungicidal concentration of pyridine chitosan against Fulvia fulva were 0.13 mg/ml and 1 mg/ml, respectively, while the corresponding values against Botrytis cinerea were 0.13 mg/ml and 4 mg/ml, respectively. Severe morphological changes of pyridine chitosan-treated B. cinerea were observed, indicative that pyridine chitosan could damage and deform the structure of fungal hyphae and subsequently inhibit strain growth. Non-toxicity of pyridine chitosan was demonstrated by an acute toxicity study. These results are beneficial for assessing the potential utilization of this chitosan derivative and for exploring new functional antifungal agents with chitosan in the food industry.

  19. Synthesis, characterization and evaluation of dewatering properties of chitosan-grafting DMDAAC flocculants.

    PubMed

    Wang, Danfeng; Zhao, Tianqi; Yan, Liuqing; Mi, Zhiming; Gu, Qiang; Zhang, Yumin

    2016-11-01

    Flocculation is one of the most widely applied techniques for water treatment and sludge dewatering. A fresh environmentally friendly and powerful flocculant is highly eager in the sludge dewatering area. In this work, a highly efficient cationic flocculant, chitosan-g-PDMDAAC was synthesized through grafting a monomer, dimethy ldiallyl ammonium chloride(DMDAAC), onto chitosan initiated by ceric sulfate under ultrasonic-assisted and conventional heating condition. The graft copolymer was characterized using FT-IR, XRD and SEM. Further, the dewatering performance of municipal activated sludge was evaluated by the filter cake moisture content and specific resistance in filtration. Its application as a flocculant for wastewater treatment was investigated. The prepared chitosan-g-PDMDAAC showed a highly effective flocculation capability for activated sludge compared with chitosan, polyacrylamide(PAM), cationic polyacrylamide(CPAM). Copyright © 2016 Elsevier B.V. All rights reserved.

  20. Preparation and Mechanical Properties of Chitosan-graft Maleic Anhydride Reinforced with Montmorillonite

    NASA Astrophysics Data System (ADS)

    Fajrin, A.; Sari, L. A.; Rahmawati, N.; Saputra, O. A.; Suryanti, V.

    2017-02-01

    The research aims to develop biodegradable composites as bio-based plastics from chitosan. The composites were prepared via solution casting method by introducing the maleic anhydride (MAH) as grafting agent and montmorillonite (MMt) as reinforcement. The grafting process of chitosan was conducted by varying concentrations of MAH which were 10, 20, and 30% w/w. It was observed that the chitosan-graft-maleic anhydride (Cs-g-MAH) containing 10% w/w of MAH increased its tensile strength by 70%. Reinforcement material was added to the Cs-g-MAH by varying MMt concentrations, e.g. 3, 6, 9 and 12% w/w. It was noted that the presence of 9% w/w of MMt in the Cs-g-MAH gave the best mechanical properties of the Cs-g-MAH/MMt composite.

  1. The use of light/chemically hardened polymethylmethacrylate, polyhydroxyethylmethacrylate, and calcium hydroxide graft material in combination with polyanhydride around implants in minipigs: part I: immediate stability and function.

    PubMed

    Hasturk, Hatice; Kantarci, Alpdogan; Ghattas, Mazen; Schmidt, Marcella; Giordano, Russell A; Ashman, Arthur; Diekwisch, Thomas G; Van Dyke, Thomas

    2011-09-01

    The present study is designed as a proof-of-concept study to evaluate light/chemical hardening technology and a newly formulated polymethylmethacrylate, polyhydroxyethylmethacrylate, and calcium hydroxide (PPCH) plus polyanhydride (PA) (PPCH-PA) composite graft material as a bone substitute compared to positive and negative controls in a minipig model. PPCH-PA (composite graft); PPCH alone (positive control), PA alone (positive control), and no graft (negative control) were compared. Four mandibular premolar teeth per quadrant were extracted; a total of 48 implants were placed into sockets in three minipigs. Abutments were placed protruding into the oral cavity 4 mm in height for immediate loading. Crestal areas and intrabony spaces were filled with PPCH-PA, PPCH, or PA using a three-phase delivery system in which all graft materials were hardened by a light cure. In the negative control group, implant sites were left untreated. At 12 weeks, block sections containing implants were obtained. Evaluations included periodontal probing, pullout-force load, and stability measurements to determine implant stability, radiographs to examine bone levels, and scanning electron microscopy (SEM)-energy-dispersed spectroscopy to determine bone-to-implant contact. Probing measurements did not reveal any pathologic pocket formation or bone loss. Radiographs revealed that immediate implant placement and loading resulted in bone at or slightly apical to the first thread of the implant in all groups at 12 weeks. Stability test values showed a relative clinical stability for all implants (range: -7 to +1); however, implants augmented with PPCH-PA exhibited a statistically significantly greater stability compared to all other groups (P <0.05). The newly formed bone in PPCH-PA-treated sites was well organized with less marrow spaces and well-distributed osteocytes. SEM revealed a tighter implant-socket interface in the PPCH-PA group compared to other groups with reduced microfissures

  2. The Use of Light/Chemically Hardened Polymethylmethacrylate, Polyhydroxyethylmethacrylate, and Calcium Hydroxide Graft Material in Combination With Polyanhydride Around Implants in Minipigs: Part I: Immediate Stability and Function

    PubMed Central

    Hasturk, Hatice; Kantarci, Alpdogan; Ghattas, Mazen; Schmidt, Marcella; Giordano, Russell A.; Ashman, Arthur; Diekwisch, Thomas G.; Van Dyke, Thomas

    2015-01-01

    Background The present study is designed as a proof-of-concept study to evaluate light/chemical hardening technology and a newly formulated polymethylmethacrylate, polyhydroxyethylmethacrylate, and calcium hydroxide (PPCH) plus polyanhydride (PA) (PPCH-PA) composite graft material as a bone substitute compared to positive and negative controls in a minipig model. Methods PPCH-PA (composite graft); PPCH alone (positive control), PA alone (positive control), and no graft (negative control) were compared. Four mandibular premolar teeth per quadrant were extracted; a total of 48 implants were placed into sockets in three minipigs. Abutments were placed protruding into the oral cavity 4 mm in height for immediate loading. Crestal areas and intrabony spaces were filled with PPCH-PA, PPCH, or PA using a three-phase delivery system in which all graft materials were hardened by a light cure. In the negative control group, implant sites were left untreated. At 12 weeks, block sections containing implants were obtained. Evaluations included periodontal probing, pullout-force load, and stability measurements to determine implant stability, radiographs to examine bone levels, and scanning electron microscopy (SEM)–energy-dispersed spectroscopy to determine bone-to-implant contact. Results Probing measurements did not reveal any pathologic pocket formation or bone loss. Radiographs revealed that immediate implant placement and loading resulted in bone at or slightly apical to the first thread of the implant in all groups at 12 weeks. Stability test values showed a relative clinical stability for all implants (range: −7 to +1); however, implants augmented with PPCH-PA exhibited a statistically significantly greater stability compared to all other groups (P <0.05). The newly formed bone in PPCH-PA–treated sites was well organized with less marrow spaces and well-distributed osteocytes. SEM revealed a tighter implant–socket interface in the PPCH-PA group compared to other

  3. Synthesis, characterization and thermal sensitivity of chitosan-based graft copolymers.

    PubMed

    Kang, Hong-Mei; Cai, Yuan-Li; Liu, Peng-Sheng

    2006-12-11

    Novel chitosan-based graft copolymers (CECTS-g-PDMA) were synthesized through homogeneous graft copolymerization of (N,N-dimethylamino)ethyl methacrylate (DMA) onto N-carboxyethylchitosan (CECTS) in aqueous solution by using ammonium persulfate (APS) as the initiator. The effect of polymerization variables, including initiator concentration, monomer concentration, reaction time and temperature, on grafting percentage was studied. XRD, FTIR, DSC and TGA were used to characterize the graft copolymers. Surface-tension measurements, turbidity measurements and temperature-variable (1)H NMR analysis were combined to investigate the thermal sensitivity of CECTS-g-PDMAs in aqueous solution.

  4. Covalent grafting of chitosan onto stainless steel through aryldiazonium self-adhesive layers.

    PubMed

    Le, Xuan Tuan; Doan, Ngoc Duc; Dequivre, Thomas; Viel, Pascal; Palacin, Serge

    2014-06-25

    Although the conventional methods for strong attachment of chitosan onto stainless steel require many steps in different solvents, it has been demonstrated in this work that covalent grafting of chitosan on a steel surface can be easily achieved through the formation of a self-adhesive surface based on aryldiazonium seed layers. Initially, a polyaminophenyl layer is grafted on a stainless steel surface by means of the one-step GraftFast(TM) process (diazonium induced anchoring process). The grafted aminophenyl groups are then converted to an aryldiazonium seed layer by simply dipping the substrate in a sodium nitrite acidic solution. That diazonium-rich grafted layer can be used as a self-adhesive surface for subsequent spontaneous coating of chitosan onto the steel surface. X-ray photoelectron and impedance electrochemical spectroscopies were used to characterize the pristine and modified steel samples. As evidenced from impedance and linear polarization results, the primary polyaminophenyl layer characterized by a high charge transfer resistance contributed to better protection against corrosion of the resulting chitosan-coated steel in sulfuric acid medium.

  5. Chitosan grafted low molecular weight polylactic acid for protein encapsulation and burst effect reduction.

    PubMed

    Di Martino, Antonio; Kucharczyk, Pavel; Zednik, Jiri; Sedlarik, Vladimir

    2015-12-30

    Chitosan and chitosan-grafted polylactic acid as a matrix for BSA encapsulation in a nanoparticle structure were prepared through a polyelectrolyte complexation method with dextran sulfate. Polylactic acid was synthetized via a polycondensation reaction using the non-metal-based initiator methanesulfonic acid and grafted to the chitosan backbone by a coupling reaction, with 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide as the condensing agent. The effect of concentration of the polymer matrix utilized herein on particle diameter, ζ-potential, encapsulation efficiency, and the release kinetic of the model protein bovine serum albumin at differing pH levels was investigated. The influence of pH and ionic strength on the behavior of the nanoparticles prepared was also researched. Results showed that grafting polylactic acid to chitosan chains reduced the initial burst effect in the kinetics of BSA release from the structure of the nanoparticles. Furthermore, a rise in encapsulation efficiency of the bovine serum albumin and diminishment in nanoparticle diameter were observed due to chitosan modification. The results suggest that both polymers actually show appreciable encapsulation efficiency; and release rate of BSA. CS-g-PLA is more suitable than unmodified CS as a carrier for controlled protein delivery.

  6. Chitosan-graft poly(p-dioxanone) copolymers: preparation, characterization, and properties.

    PubMed

    Wang, Xiu-Li; Huang, Yan; Zhu, Jiang; Pan, Yan-Bo; He, Rui; Wang, Yu-Zhong

    2009-04-21

    A new biodegradable copolymer of chitosan and poly(p-dioxanone) (PPDO) was prepared through a protection-graft-deprotection procedure using N-phthaloyl-chitosan as an intermediate. PPDO terminated with the isocyanate group was allowed to react with hydroxyl groups of the N-phthaloyl-protected chitosan, and then the phthaloyl group was cleaved to give the free amino groups. The length of PPDO graft chains can be controlled easily by using the prepolymers of PPDO with different molecular weights. The resulting products were thoroughly characterized with FT-IR, (1)H NMR, TG, DSC, SEM, and WAXD. The copolymers were used as drug carriers for sinomenine (7,8-didehydro-4-hydroxy-3,7-dimethoxy-17-methyl-9alpha,13alpha,14alpha-morphinan-6-one) and these exhibited a significant controlled drug-releasing behavior whether in artificial gastric juice or in neutral phosphate buffer solution.

  7. Inhibition of Listeria monocytogenes in Fresh Cheese Using Chitosan-Grafted Lactic Acid Packaging.

    PubMed

    Sandoval, Laura N; López, Monserrat; Montes-Díaz, Elizabeth; Espadín, Andres; Tecante, Alberto; Gimeno, Miquel; Shirai, Keiko

    2016-04-08

    A chitosan from biologically obtained chitin was successfully grafted with d,l-lactic acid (LA) in aqueous media using p-toluenesulfonic acid as catalyst to obtain a non-toxic, biodegradable packaging material that was characterized using scanning electron microscopy, water vapor permeability, and relative humidity (RH) losses. Additionally, the grafting in chitosan with LA produced films with improved mechanical properties. This material successfully extended the shelf life of fresh cheese and inhibited the growth of Listeria monocytogenes during 14 days at 4 °C and 22% RH, whereby inoculated samples with chitosan-g-LA packaging presented full bacterial inhibition. The results were compared to control samples and commercial low-density polyethylene packaging.

  8. Original method for synthesis of chitosan-based antimicrobial agent by quaternary ammonium grafting.

    PubMed

    Oyervides-Muñoz, Ernesto; Pollet, Eric; Ulrich, Gilles; de Jesús Sosa-Santillán, Gerardo; Avérous, Luc

    2017-02-10

    Functionalized high molar mass chitosan derivatives with increased antibacterial properties were prepared by the reaction of chitosan with different quaternary ammonium salts. Benzalkonium bromide, pyridinium bromide and triethyl ammonium bromide were synthesized by a quaternization reaction between 1,4-dibromobutane and the respective tertiary amines (N, N-dimethylbenzylamine, triethylamine and pyridine) to obtain three ammonium salts with a bromide end-group capable of reacting with a functional group from the chitosan backbone. The ammonium salts were chemically grafted along the chitosan macromolecular chains. Four different chitosan derivatives were obtained and their chemical structures analyzed and confirmed by (1)H NMR and FT-IR. The corresponding thermal stability was analyzed by TGA. Antibacterial activity has been assessed by determining their minimal inhibitory concentration upon Escherichia coli and Staphylococcus aureus. Furthermore, the antibiogram method was used to complement the antibacterial analysis. The bacteria inhibitory property of the chitosan derivatives exhibited a remarkable improvement compared to unmodified chitosan. Copyright © 2016 Elsevier Ltd. All rights reserved.

  9. Chitosan-graft-poly(n-butyl acrylate) copolymer: Synthesis and characterization of a natural/synthetic hybrid material.

    PubMed

    Anbinder, Pablo; Macchi, Carlos; Amalvy, Javier; Somoza, Alberto

    2016-07-10

    Two chitosan polymers with different deacetylation degree and molecular weight were subjected to grafting reactions with the aim to enhance the properties of these bio-based materials. Specifically, n-butyl acrylate in different proportions was grafted onto two different deacetylation degree (DD%) chitosan using radical initiation in a surfactant free emulsion system. Infrared spectroscopy was used to confirm grafting and products grafting percentage and efficiency were evaluated against acrylate/chitosan ratio and DD%. Thermal and structural properties and the behavior against water of the raw and grafted biopolymers were studied using several experimental techniques: differential scanning calorimetry, transmission electron microscopy, dynamic light scattering, water swelling, contact angle and positron annihilation lifetime spectroscopy. The influence of the grafting process on the morphological and physicochemical properties of the prepared natural/synthetic hybrid materials is discussed. Copyright © 2016 Elsevier Ltd. All rights reserved.

  10. Radiation-induced graft polymerization of chitosan onto poly(3-hydroxybutyrate).

    PubMed

    Torres, Maykel González; Muñoz, Susana Vargas; Rosales, Silvia G Solís; Carreón-Castro, Ma del Pilar; Muñoz, Rodrigo Alonso Esparza; González, Roberto Olayo; González, Miriam Rocío Estévez; Talavera, Rogelio Rodríguez

    2015-11-20

    Chitosan is among the most studied biopolymers and offers important advantages, such as biodegradability, biocompatibility and nontoxicity. In this study, this polysaccharide was grafted onto poly(3-hydroxybutyrate) using the simultaneous gamma-irradiation-initiated polymerization method. The polyester was immersed in diverse solvents, which allowed the preparation of graft copolymers with different yields and crystallinities. A successful synthesis and the estimation of the degree of crystallinity were verified by spectroscopic and calorimetric techniques. The most suitable method was found to be the thermoanalytical approach because it displayed a linear relationship between the degree of crystallinity and the increasing degree of grafting. The results also indicated that the lowest degree of grafting was seen for acetic acid (14.27%), while the highest degree corresponded to ethyl acetate (32.11%). The mechanism of grafting was proposed on the basis of the experimental results.

  11. Capillary Electrophoresis to Monitor Peptide Grafting onto Chitosan Films in Real Time.

    PubMed

    Thevarajah, Joel J; O'Connor, Michael D; Castignolles, Patrice; Gaborieau, Marianne

    2016-10-26

    Free-solution capillary electrophoresis (CE) separates analytes, generally charged compounds in solution through the application of an electric field. Compared to other analytical separation techniques, such as chromatography, CE is cheap, robust and effectively requires no sample preparation (for a number of complex natural matrices or polymeric samples). CE is fast and can be used to follow the evolution of mixtures in real time (e.g., chemical reaction kinetics), as the signals observed for the separated compounds are directly proportional to their quantity in solution. Here, the efficiency of CE is demonstrated for monitoring the covalent grafting of peptides onto chitosan films for subsequent biomedical applications. Chitosan's antimicrobial and biocompatible properties make it an attractive material for biomedical applications such as cell growth substrates. Covalently grafting the peptide RGDS (arginine - glycine - aspartic acid - serine) onto the surface of chitosan films aims at improving cell attachment. Historically, chromatography and amino acid analysis have been used to provide a direct measurement of the amount of grafted peptide. However, the fast separation and absence of sample preparation provided by CE enables equally accurate yet real-time monitoring of the peptide grafting process. CE is able to separate and quantify the different components of the reaction mixture: the (non-grafted) peptide and the chemical coupling agents. In this way the use of CE results in improved films for downstream applications. The chitosan films were characterized through solid-state NMR (nuclear magnetic resonance) spectroscopy. This technique is more time-consuming and cannot be applied in real time, but yields a direct measurement of the peptide and thus validates the CE technique.

  12. Oleic acid-grafted chitosan/graphene oxide composite coating for corrosion protection of carbon steel.

    PubMed

    Fayyad, Eman M; Sadasivuni, Kishor Kumar; Ponnamma, Deepalekshmi; Al-Maadeed, Mariam Al Ali

    2016-10-20

    An anticorrosion coating film based on the formation of nanocomposite coating is reported in this study. The composite consisted of chitosan (green matrix), oleic acid, and graphene oxide (nano filler). The nanocomposite coating was arranged on the surface of carbon steel, and the corrosion resistance was monitored using electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization (PP). Compared to the pure chitosan (CS) coating, the corrosion resistance of oleic acid-modified chitosan/graphene oxide film (CS/GO-OA) is increased by 100 folds. Since the well-dispersed smart grafted nanolayers delayed the penetration rate of corrosive species and thus maintained long term anticorrosive stability which is correlated with hydrophobicity and permeability.

  13. Red fluorescent chitosan nanoparticles grafted with poly(2-methacryloyloxyethyl phosphorylcholine) for live cell imaging.

    PubMed

    Wang, Ke; Fan, Xingliang; Zhang, Xiaoyong; Zhang, Xiqi; Chen, Yi; Wei, Yen

    2016-08-01

    Poly(2-methacryloyloxyethyl phosphorylcholine) conjugated red fluorescent chitosan nanoparticles (GCC-pMPC) were facilely fabricated by "grafting from" method via surface initiated atom transfer radical polymerization (ATRP). Firstly, glutaraldehyde crosslinked red fluorescent chitosan nanoparticles (GCC NPs) with many amino groups and hydroxyl groups on their surface were prepared, which were then reacted with 2-bromoisobutyryl bromide to form GCC-Br; subsequently, poly(MPC) (pMPC) brushes were grafted onto GCC NPs surface using GCC-Br as initiator via ATRP. Compared with PEGylated nanoparticles, zwitterionic polymers modified nanoparticles demonstrated better performance in their cellular uptake. Moreover, the obtained GCC-pMPC demonstrated excellent water-dispersibility, biocompatibility, and photostability, which made them highly potential for long-term tracing applications. Importantly, the successful live cell imaging of GCC-pMPC would remarkably advance the research of their further bioapplications.

  14. Chitosan graft copolymer nanoparticles for oral protein drug delivery: preparation and characterization.

    PubMed

    Qian, Feng; Cui, Fuying; Ding, Jieying; Tang, Cui; Yin, Chunhua

    2006-10-01

    Several novel functionalized graft copolymer nanoparticles consisting of chitosan (CS) and the monomer methyl methacrylate (MMA), N-dimethylaminoethyl methacrylate hydrochloride (DMAEMC), and N-trimethylaminoethyl methacrylate chloride (TMAEMC), which show a higher solubility than chitosan in a broader pH range, have been prepared by free radical polymerization. The nanoparticles were characterized in terms of particle size, zeta potential, TEM, and FT-IR. These nanoparticles were 150-280 nm in size and carried obvious positive surface charges. Protein-loaded nanoparticles were prepared, and their maximal encapsulation efficiency was up to 100%. In vitro release showed that these nanoparticles provided an initial burst release followed by a slowly sustained release for more than 24 h. These graft copolymer nanoparticles enhanced the absorption and improved the bioavailability of insulin via the gastrointestinal (GI) tract of normal male Sprague-Dawley (SD) strain rats to a greater extent than that of the phosphate buffer solution (PBS) of insulin.

  15. Chemical modification of chitosan film via surface grafting of citric acid molecular to promote the biomineralization

    NASA Astrophysics Data System (ADS)

    Liu, Yang; Shen, Xin; Zhou, Huan; Wang, Yingjun; Deng, Linhong

    2016-05-01

    We develop a novel chitosan-citric acid film (abbreviated as CS-CA) suitable for biomedical applications in this study. In this CS-CA film, the citric acid, which is a harmless organic acid has been extensively investigated as a modifying agent on carbohydrate polymers, was cross-linked by 1-Ethyl-3-(3-dimethyl aminopropyl) carbodiimide (EDC) and N-hydroxysuccinimide (NHS) onto the surface of chitosan (CS) film. Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) confirms the graft copolymerization of the modified chitosan film (CS-CA). Surface wettability, moisturizing performance, the capacity of mineralization in vitro and biocompatibility of the films were characterized. After modification, this CS-CA film has good hydrophilicity. It is very evident that the citric acid grafting treatment significantly promotes the biomineralization of the chitosan based substrates. Cell experiments show that the MC3T3-E1 osteoblasts can adhere and proliferate well on the surface of CS-CA film. This CS-CA film, which can be prepared in large quantities and at low cost, should have potential application in bone tissue engineering.

  16. Synthesis, characterization, and biocompatible properties of alanine-grafted chitosan copolymers.

    PubMed

    Park, Gyu Han; Kang, Min-Sil; Knowles, Jonathan C; Gong, Myoung-Seon

    2016-04-01

    In order to overcome major problems regarding the lack of affinity to solvents and limited reactivity of the free amines of chitosan, introduction of appropriate spacer arms having terminal amine function is considered of interest. L-Alanine-N-carboxyanhydride was grafted onto chitosan via anionic ring-opening polymerization. The chemical and structural characterizations of L-alanine-grafted chitosan (Ala-g-Cts) were confirmed through Fourier transform infrared spectroscopy and proton nuclear magnetic resonance spectroscopy ((1)H NMR). In addition, the viscoelastic properties of Ala-g-Cts were examined by means of a rotational viscometer, and thermal analysis was carried out with a thermogravimetric analyzer and differential scanning calorimetry. Morphological changes in the chitosan L-alanine moiety were determined by x-ray diffraction. To determine the feasibility of using these films as biomedical materials, we investigated the effects of their L-alanine content on physical and mechanical properties. The biodegradation results of crosslinked Ala-g-Cts films were evaluated in phosphate-buffered solution containing lysozyme at 37℃. Proliferation of MC3T3-E1 cells on crosslinked Ala-g-Cts films was also investigated with use of the CCK-8 assay.

  17. Synthesis and characterization of new biocompatible copolymer: chitosan-graft-polyaniline

    NASA Astrophysics Data System (ADS)

    Sedaghat, Sajjad

    2014-03-01

    Polyaniline as a conductive polymer and chitosan as a natural polymer have been reacted with formaldehyde as grafting agent and potassium persulfate as an initiator. The effect of using specific primer, different ratio of monomers and the solubility of synthesized copolymer has been studied and analyzed. Characterization of this new copolymer were occurred by Fourier transform infrared spectroscopy, UV-visible, scanning electron microscopy and differential scanning calorimetry technique.

  18. Free radical grafting kinetics of acrylamide onto a blend of starch/chitosan/alginate.

    PubMed

    Sorour, Mohamed; El-Sayed, Marwa; El Moneem, Nabil Abd; Talaat, Hala; Shaalan, Hayam; El Marsafy, Sahar

    2013-10-15

    Grafting of monomer onto polymer backbone is one of the effective and accessible methods for the chemical modification of polysaccharides. Grafting of acrylamide (AAm) onto polysaccharides blend (PsB) composed of starch, chitosan and alginate has been carried out using potassium persulfate (KPS) as an initiator. The kinetics of the grafting polymerization also has been studied. The grafting parameters have been evaluated by changing the initial concentrations of AAm from 8 to 16 g, PsB from 6 to 14 g and KPS from 0.2 to 1 g. Evidence of grafting has been obtained from FTIR, XRD and TGA. The kinetics of the grafting polymerization also has been studied. The grafting rate equation of the produced hydrogel (PsB-g-AAm) hydrogel has been expressed by: Rg=k[AAm] [PsB](0.5) [KPS](0.5). The grafting rate is a first order dependence to [AAm] initial concentration and square root to [PsB] and [KPS] initial concentrations in the used concentrations range.

  19. Thermo-responsive wound dressings by grafting chitosan and poly(N-isopropylacrylamide) to plasma-induced graft polymerization modified non-woven fabrics

    NASA Astrophysics Data System (ADS)

    Chen, Jyh-Ping; Kuo, Chang-Yi; Lee, Wen-Li

    2012-12-01

    To obtain a chitosan wound dressings with temperature-responsive characteristics, polypropylene (PP) non-woven fabric (NWF) was modified by direct current pulsed oxygen plasma-induced grafting polymerization of acrylic acid (AAc) to improve hydrophilicity and to introduce carboxylic acid groups. Conjugation of chitosan and poly(N-isopropylacrylamide) (PNIPAAm) followed by using water-soluble carbodiimide as a coupling agent to form a novel bigraft PP-g-chitosan-g-PNIPAAm wound dressing. The amount of chitosan and PNIPAAm grafted to PP-g-chitosan-g-PNIPAAm were 83.0 ± 4.6 μg/cm2 and 189.5 ± 8.2 μg/cm2, respectively. The surface chemical composition and microstructure of the NWF were studied by electron spectroscopy for chemical analysis (ESCA) and scanning electron microscopy (SEM). The linkages between AAc, chitosan, and PNIPAAm were confirmed with the formation of amide bonds. Physical properties of the NWF were characterized and potentials of these NWFs as wound dressings were evaluated using SD rat as the animal model. NWFs contained PNIPAAm were better than those contained only chitosan in wound healing rates and the wound areas covered by PP-g-chitosan-g-PNIPAAm wound dressings healed completely in 17 days.

  20. Synthesis and characterization of chitosan-silicate hydrogel as resorbable vehicle for bonelike-bone graft.

    PubMed

    Shirosaki, Yuki; Botelho, Cláudia M; Lopes, Maria A; Santos, José D

    2009-06-01

    The use of bone grafts is required to restore skeletal integrity and enhance bone healing of large defects in several areas of regenerative medicine, such as: orthopedic and maxillofacial procedures. Some of these bone grafts can be resorbed in a time controlled way, in order to allow the correct process of natural re-construction of the involved bone tissue to occur. The Bonelike graft is a bone substitute that mimics the inorganic composition of bone; this biomaterial was developed and characterized over the last decade. In a granular form, Bonelike has proved its highly bioactive behavior in medical applications, such as; maxillofacial and orthopedics surgery. The clinical applications in maxillary bone defects indicated a good bone bonding between new formed bone and the Bonelike granules. The purpose of this study was to develop a new injectable system for the application of Bonelike using a resorbable vehicle which may be used in minimal invasive surgery. A new hydrogel derived from chitosan and y-glycidoxypropyltrimethoxysilane (GPTMS) was synthesized and characterized. The mixture derived from chitosan and GPTMS existed in sol state at room temperature and formed a hydrogel at 37 degrees C. The degradability of the hydrogel could be controlled by the concentration of chitosan and GPTMS, and the presence the presence of Bonelike did not affect its degradability. The pH changes caused by the degradation of this hydrogel were small, so it is not expected to cause any deleterious effect in vivo conditions.

  1. Synthesis, characterization and stability of chitosan and poly(methyl methacrylate) grafted carbon nanotubes.

    PubMed

    Carson, Laura; Hibbert, Kemar; Akindoju, Feyisayo; Johnson, Chevaun; Stewart, Melisa; Kelly-Brown, Cordella; Beharie, Gavannie; Fisher, Tavis; Stone, Julia; Stoddart, Dahlia; Oki, Aderemi; Neelgund, Gururaj M; Regisford, Gloria; Traisawatwong, Pasakorn; Zhou, Jianren; Luo, Zhiping

    2012-10-01

    The single walled carbon nanotubes (CNTs) were effectively functionalized through grafting with chitosan (CTS) and poly(methyl methacrylate) (PMMA). Prior to grafting reaction, the carboxylated SWNCTs (SWNCTs-COOH) were obtained by treating pristine CNTs with a mixture of 3:1 (v/v) H(2)SO(4) and HNO(3), and the successive treatment of SWNCTs-COOH with SOCl(2) yielded the acylated CNTs (CNTs-COCl). The functionalized derivatives of CNTs were characterized using Fourier transform infrared spectroscopy, thermogravimetric analysis, atomic force microscopy, scanning electron microscopy and transmission electron microscopy. Both CTS and PMMA grafted CNTs showed better dispersability in acetic acid and tetrahydrofuran, in addition to higher stability in solution.

  2. Synthesis, characterization and stability of chitosan and poly(methyl methacrylate) grafted carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Carson, Laura; Hibbert, Kemar; Akindoju, Feyisayo; Johnson, Chevaun; Stewart, Melisa; Kelly-Brown, Cordella; Beharie, Gavannie; Fisher, Tavis; Stone, Julia; Stoddart, Dahlia; Oki, Aderemi; Neelgund, Gururaj M.; Regisford, Gloria; Traisawatwong, Pasakorn; Zhou, Jianren; Luo, Zhiping

    2012-10-01

    The single walled carbon nanotubes (CNTs) were effectively functionalized through grafting with chitosan (CTS) and poly(methyl methacrylate) (PMMA). Prior to grafting reaction, the carboxylated SWNCTs (SWNCTs-COOH) were obtained by treating pristine CNTs with a mixture of 3:1 (v/v) H2SO4 and HNO3, and the successive treatment of SWNCTs-COOH with SOCl2 yielded the acylated CNTs (CNTs-COCl). The functionalized derivatives of CNTs were characterized using Fourier transform infrared spectroscopy, thermogravimetric analysis, atomic force microscopy, scanning electron microscopy and transmission electron microscopy. Both CTS and PMMA grafted CNTs showed better dispersability in acetic acid and tetrahydrofuran, in addition to higher stability in solution.

  3. The Use of Light/Chemically Hardened Polymethylmethacrylate, Polyhydroxylethylmethacrylate, and Calcium Hydroxide Graft Material in Combination With Polyanhydride Around Implants and Extraction Sockets in Minipigs: Part II: Histologic and Micro-CT Evaluations

    PubMed Central

    Hasturk, Hatice; Kantarci, Alpdogan; Ghattas, Mazen; Dangaria, Smit J.; Abdallah, Rima; Morgan, Elise F.; Diekwisch, Thomas G.H.; Ashman, Arthur; Van Dyke, Thomas

    2015-01-01

    Background This report is the second part of the previously published study on the impact of light/chemical hardening technology and a newly formulated composite graft material for crestal augmentation during immediate implant placement. Methods A total of 48 implants were placed into the sockets of the mesial roots of freshly extracted mandibular premolar teeth in three minipigs. Crestal areas and intrabony spaces were randomly augmented with light-hardened graft materials including a composite graft consisting of polymethylmethacrylate, polyhydroxylethylmethacrylate, and calcium hydroxide (PPCH) plus polyanhydride (PA); PPCH graft; and PA graft, or left untreated. Distal sockets not receiving implants and the sockets of first molars (n = 60) were randomly treated with one of the graft materials or left empty. In addition, two molar sockets were treated with the original PPCH graft material. Quantitative microcomputed tomography (micro-CT) was used to assess alveolar bone structure and tissue compositions. Histologic evaluations included descriptive histology to assess the peri-implant wound healing, as well as histomorphometric measurements to determine bone-to-implant contact (BIC). Results Both trabecular and cortical bone measurements by micro-CT did not reveal any significant differences among the groups. Sites augmented with PPCH+PA resulted in significantly greater BIC surface than PPCH alone and no-graft-treated implants (P <0.05) histologically. Stained ground sections showed complete bone formation between bone and implant surface in the PPCH+PA group, whereas sites without augmentation showed large gaps between bone and implant surfaces, indicating a slower bone apposition and less BIC surface compared to all other groups. Similar to implant sections, all materials showed positive outcome on trabecular and cortical bone formation in extraction sockets with an intact crestal cortical bone. Conclusion Histologic evaluations supported the previous findings

  4. Preparation, blood coagulation and cell compatibility evaluation of chitosan-graft-polylactide copolymers.

    PubMed

    Wang, Qi; Liu, Pei; Liu, Peifeng; Gong, Tao; Li, Suming; Duan, Yourong; Zhang, Zhirong

    2014-02-01

    Biodegradable chitosan-graft-polylactide (PLA-CS) copolymers were prepared by the grafting of a poly(L-lactide) (PLLA) or poly(D-lactide) (PDLA) precursor to the backbone of chitosan using 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDC ⋅ HCl) and N-hydroxysuccinimide (NHS) as a coupling agent. The blood and cell compatibility of the graft copolymers were investigated in comparison to PLLA and PDLA homopolymers. The coagulation properties of PLA-CS were evaluated by hemolysis, plasma recalcification, dynamic blood clotting and protein absorption assays. PLA-CS copolymers present similar hemolysis ratio and plasma recalcification time as PLA, but slower dynamic blood clotting and lower protein absorption. The cell viability was assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), agar diffusion and lactate dehydrogenase (LDH) experiments. All the samples presented no effect on the viability to cells. Inflammatory cytokine analysis using sandwich ELISAs revealed that PLA-CS would not stimulate inflammatory activity.

  5. Improvement in physical and biological properties of chitosan/soy protein films by surface grafted heparin.

    PubMed

    Wang, Xiaomei; Hu, Ling; Li, Chen; Gan, Li; He, Meng; He, Xiaohua; Tian, Weiqun; Li, Mingming; Xu, Li; Li, Yinping; Chen, Yun

    2016-02-01

    A series of chitosan/soy protein isolate (SPI) composite films (CS-n, n=0, 10 and 30, corresponding to SPI content in the composites) were prepared. Heparin was grafted onto the surface of CS-n to fabricate a series of heparinized films (HCS-n). CS-n and HCS-n were characterized by ATR-Fourier transform infrared spectroscopy and water contact angle. The surface heparin density was measured by toluidine blue assay. The results showed that heparin has been successfully grafted onto the surface of CS-n. Heparin evenly distributed on the surface of the films and the heparin content increased with the increase of SPI content, and the hydrophilicity of the films was enhanced due to the grafted heparin. The cytocompatibility and hemocompatibility of CS-n and HCS-n were evaluated by cell culture (MTT assay, live/dead assay, cell morphology and cell density observation), platelet adhesion test, plasma recalcification time (PRT) measurement, hemolysis assay and thrombus formation test. HCS-n showed higher cell adhesion rate and improved cytocompatibility compared to the corresponding CS-n. HCS-n also exhibited lower platelet adhesion, longer PRT, higher blood anticoagulant indexes (BCI) and lower hemolysis rate than the corresponding CS-n. The improved cytocompatibility and hemocompatibility of HCS-n would shed light on the potential applications of chitosan/soy protein-based biomaterials that may come into contact with blood.

  6. Effect of Protocatechuic Acid-Grafted-Chitosan Coating on the Postharvest Quality of Pleurotus eryngii.

    PubMed

    Liu, Jun; Meng, Chen-Guang; Wang, Xing-Chi; Chen, Yao; Kan, Juan; Jin, Chang-Hai

    2016-09-28

    Protocatechuic acid-grafted-chitosan (PA-g-CS) solution with antioxidant activity was developed as a novel edible coating material for Pleurotus eryngii postharvest storage. The effect of PA-g-CS coating on the postharvest quality of P. eryngii was investigated by determination of various physicochemical parameters and enzyme activities. Results showed that the antioxidant capacity and viscosity of PA-g-CS solutions were closely related to the grafting degree and were much higher than that of chitosan (CS) solution. At the end of 15 days of storage, serious mushroom browning was observed in the control and CS coating groups. By contrast, PA-g-CS coating groups with medium and high grafting degrees maintained better physical appearance. Among all of the treatment groups, P. eryngii in PA-g-CS III coating group exhibited the highest firmness and the lowest weight loss, browning degree, respiration rate, malondialdehyde content, electrolyte leakage rate, superoxide anion production rate, and hydrogen peroxide content. Moreover, P. eryngii in PA-g-CS III coating group maintained relatively higher antioxidant enzyme activities but lower polyphenol oxidase activity than other treatment groups. Therefore, PA-g-CS III is a promising preservation agent for P. eryngii.

  7. Effect of gamma radiation on the mechanical and barrier properties of HEMA grafted chitosan-based films

    NASA Astrophysics Data System (ADS)

    Khan, Avik; Huq, Tanzina; Khan, Ruhul A.; Dussault, Dominic; Salmieri, Stephane; Lacroix, Monique

    2012-08-01

    Chitosan films were prepared by dissolving 1% (w/v) chitosan powder in 2% (w/v) aqueous acetic acid solution. Chitosan films were prepared by solution casting. The values of puncture strength (PS), viscoelasticity coefficient and water vapor permeability (WVP) of the films were found to be 565 N/mm, 35%, and 3.30 g mm/m2 day kPa, respectively. Chitosan solution was exposed to gamma irradiation (0.1-5 kGy) and it was revealed that PS values were reduced significantly (p≤0.05) after 1 kGy dose and it was not possible to form films after 5 kGy. Monomer, 2-hydroxyethyl methacrylate (HEMA) solution (0.1-1%, w/v) was incorporated into the chitosan solution and the formulation was exposed to gamma irradiation (0.3 kGy). A 0.1% (w/v) HEMA concentration at 0.3 kGy dose was found optimal-based on PS values for chitosan grafting. Then radiation dose (0.1-5 kGy) was optimized for HEMA grafting. The highest PS values (672 N/mm) were found at 0.7 kGy. The WVP of the grafted films improved significantly (p≤0.05) with the rise of radiation dose.

  8. Chitosan-based hydrogels for developing a small-diameter vascular graft: in vitro and in vivo evaluation.

    PubMed

    Aussel, Audrey; Thébaud, Noélie; Berard, Xavier; Brizzi, Vincenzo; Delmond, Samantha; Bareille, Reine; Siadous, Robin; James, Chloe; Ripoche, Jean; Durand, Marlène; Montembault, Alexandra; Burdin, Béatrice; Letourneur, Didier; L'Heureux, Nicolas; David, Laurent; Bordenave, Laurence

    2017-06-12

    Vascular grafts made of synthetic polymers perform poorly in small-diameter applications (cardiac and peripheral bypass). Chitosan is a biocompatible natural polymer that can provide a novel biological scaffold for tissue engineering development. The goal of this study was to demonstrate the biocompatibility of a novel chitosan preparation in vitro and in vivo, and to assess its potential as a scaffold for vascular applications. Methods and Results. A series of experiments of increasing complexity, ranging from in vitro biocompatibility and hemocompatibility tests to in vivo studies in small and large animals (rat and sheep), was performed to provide a comprehensive analysis of chitosan hydrogels' biological properties. In vitro studies established that: i) chitosan supported human endothelial progenitor cells adhesion, proliferation and resistance to physiological shear stress; ii) chitosan did not activate platelets, the complement system, or the intrinsic coagulation pathway. In vivo results showed: iii) no resorption of chitosan and no chronic inflammation at 60 days in a rat heterotopic implantation model (magnetic resonance imaging and histology); iv) no flow obstruction (Doppler ultrasound) and no thrombus formation (histology and scanning electron microscopy) at 2 hours after a carotid arteriotomy repair with chitosan patches in sheep. Finally, 2 chitosan tubes were implanted as carotid interposition grafts for 3 days in sheep showing that chitosan was strong enough to be sutured, to withstand arterial pressure, and no flow obstruction was observed through this short period. Conclusion. Chitosan-based hydrogels displayed promising in vitro biocompatibility and hemocompatibility properties as well as in vivo short-term performance. . © 2017 IOP Publishing Ltd.

  9. In Vitro Antioxidant-Activity Evaluation of Gallic-Acid-Grafted Chitosan Conjugate Synthesized by Free-Radical-Induced Grafting Method.

    PubMed

    Hu, Qiaobin; Wang, Taoran; Zhou, Mingyong; Xue, Jingyi; Luo, Yangchao

    2016-07-27

    The major objective of this work was to develop a green and facile process to prepare gallic acid-chitosan conjugate and comprehensively evaluate the physicochemical properties and biological activities of an as-prepared water-soluble chitosan derivative. A free-radical-induced grafting approach using an ascorbic acid-hydrogen peroxide redox pair was adopted. The obtained conjugate was characterized by Fourier transform infrared spectroscopy, UV-vis, X-ray diffraction, and pKa analysis. The antioxidant activities were evaluated by 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2'-azino-bis(3-ethylbenzothiazoline-6)-sulphonic acid (ABTS), reducing power, and oxygen-radical antioxidant-capacity assays. The results showed that the mass ratio of gallic acid to chitosan played a vital role in determining the grafting degree and ζ potential of the conjugates, with the ratio of 0.5:1 being the optimal ratio that resulted in the highest grafting degree. The antioxidant assays demonstrated that conjugation significantly improved the antioxidant activities, being dramatically higher than that of free chitosan. It was notable that the DPPH- and ABTS-scavenging activities of conjugate at 0.4 mg/mL reached the same level as the free gallic acid at the equivalent concentration. Our study demonstrated a green and facile synthesis approach to preparing a novel water-soluble chitosan derivative that may have promising potentials in the food industry.

  10. Enhancement of surface graft density of MPEG on alginate/chitosan hydrogel microcapsules for protein repellency.

    PubMed

    Zheng, Jiani; Xie, Hongguo; Yu, Weiting; Tan, Mingqian; Gong, Faquan; Liu, Xiudong; Wang, Feng; Lv, Guojun; Liu, Wanfa; Zheng, Guoshuang; Yang, Yan; Xie, Weiyang; Ma, Xiaojun

    2012-09-18

    Alginate/chitosan/alginate (ACA) hydrogel microcapsules were modified with methoxy poly(ethylene glycol) (MPEG) to improve protein repellency and biocompatibility. Increased MPEG surface graft density (n(S)) on hydrogel microcapsules was achieved by controlling the grafting parameters including the buffer layer substrate, membrane thickness, and grafting method. X-ray photoelectron spectroscopy (XPS) model was employed to quantitatively analyze n(S) on this three-dimensional (3D) hydrogel network structure. Our results indicated that neutralizing with alginate, increasing membrane thickness, and in situ covalent grafting could increase n(S) effectively. ACAC(PEG) was more promising than ACC(PEG) in protein repellency because alginate supplied more -COO(-) negative binding sites and prevented MPEG from diffusing. The n(S) increased with membrane thickness, showing better protein repellency. Moreover, the in situ covalent grafting provided an effective way to enhance n(S), and 1.00 ± 0.03 chains/nm(2) was achieved, exhibiting almost complete immunity to protein adsorption. This antifouling hydrogel biomaterial is expected to be useful in transplantation in vivo.

  11. [Flocculation of kaolin suspensions by chitosan grafted ternary polymerization flocculant].

    PubMed

    Hu, Yong-you; Li, Si-qing; Guo, Yan-ping; Cheng, Jian-hua

    2008-04-01

    Flocculation of kaolin suspensions using ternary polymerization flocculant (CAS) synthesized by chitosan (CTS), acrylamide and ethyl acrylate quaternary ammonium salt was investigated in lab-scale. It was found that CAS had more advantages such as higher flocculation efficiency, lesser dosage and wider pH flocculation range than CTS. CAS was insignificantly exposed to the properties of suspended particles, so preferable flocculation efficiency by it could be obtained both with distilled water and tap water kaolin suspensions. The optimal dosage for CAS was only one-tenth of that of CTS in neutral condition. Good flocculation performance was observed in the pH range of 2.0-11.0 at the dosage of 0.5 mg x L(-1) CAS, and the turbidity removal rates were about 95%. It was also shown that flocculation efficiency was very sensitive to the raw turbidity of kaolin suspensions. At less than 0.5 mg x L(-1) of CAS dose, the higher raw turbidity of the suspension contrarily yielded a lower removing rate. However, when the dosage of CAS was more than 0.5 mg x L(-1), the flocculation efficiency increased with increasing the raw turbidity of kaolin. When the dosage was more than 1.0 mg x L(-1), turbidity removal efficiencies exceeding 85% could be achieved in overall experimental turbidities from 10 to 160 NTU. iPDA-100 device was used to follow the particle aggregation process. And also zeta potential values of particles,floc sizes, shape analyses were presented. It is presumed that the flocculation induced by CAS is dominated by charge patch mechanism and bond bridging. The flocculation reactivity of kaolin suspensions exhibits a dynamic changing, which is simultaneously responsible for several kinds of driving forces.

  12. The effect of collagen-chitosan porous scaffold thickness on dermal regeneration in a one-stage grafting procedure.

    PubMed

    Haifei, Shi; Xingang, Wang; Shoucheng, Wu; Zhengwei, Mao; Chuangang, You; Chunmao, Han

    2014-01-01

    Dermal substitutes are used as dermal regeneration templates to reduce scar formation and improve wound healing. Unlike autografts, dermal substitutes lack normal vascular networks. The increased distance required for diffusion of oxygen and nutrients to the autograft following interpositioning of the substitute dramatically affects graft survival. To evaluate the effect of collagen-chitosan scaffold thickness on dermal regeneration, single-layer collagen-chitosan porous scaffolds of 0.5-, 1- and 2-mm thicknesses were fabricated and used to treat full-thickness wounds in a one-stage grafting procedure in a rat model. Skin-graft viability, wound contraction, histological changes, and wound tensile strength were evaluated. The results indicated that the distance for the diffusion of oxygen and nutrients to the autograft in the 2-mm-thick scaffold provided less support for graft take, which resulted in graft necrosis, extensive inflammatory reaction, marked foreign-body reaction (FBR), rapid scaffold degradation, and abnormal collagen deposition and remodeling. In contrast, the thinner scaffolds, especially of that 0.5-mm thickness, promoted earlier angiogenesis, ensuring skin-graft viability with a mild FBR, and ordered fibroblast infiltration and better collagen remodeling. It can be concluded that collagen-chitosan porous scaffolds with a thickness of <1mm are more suitable for dermal regeneration and can be used as dermal templates for treatment of dermal defects using a one-stage grafting procedure. © 2013 Elsevier Ltd. All rights reserved.

  13. Synthesis, characterization and antimicrobial activity of biodegradable conducting polypyrrole-graft-chitosan copolymer

    NASA Astrophysics Data System (ADS)

    Cabuk, Mehmet; Alan, Yusuf; Yavuz, Mustafa; Unal, Halil Ibrahim

    2014-11-01

    In this study, polypyrrole-graft-chitosan (PPy-g-CS) copolymer was chemically synthesized and its structural and morphological properties characterized by FTIR, UV-vis, SEM, XRD, TGA and zeta-potential techniques. The results revealed that there were strong interactions between PPy and CS chains. The electrical conductivity of CS increased to semiconducting range by grafting. The crystallinity and thermal stability of PPy-g-CS copolymer improved when compared to CS. The copolymer was tested against various bacterial and fungal strains at various concentrations and results obtained were compared with the reference antibiotics. The results indicated that the antibacterial activity of PPy-g-CS copolymer was stronger than CS and PPy alone. The antibacterial activity of the PPy-g-CS copolymer observed to increase with rising concentration, and showed stronger activity against bacteria than Penicillin (10 mg), Rifampicin (5 mg) and Trimethoprim (25 mg), whereas showed equipotent activity with Amikacin (30 mg) and Erythromycin (15 mg) antibiotics.

  14. Grafting Chitosan with Polyethylenimine in an Ionic Liquid for Efficient Gene Delivery

    PubMed Central

    Chen, Huiying; Cui, Shaohui; Zhao, Yinan; Zhang, Chuanmin; Zhang, Shubiao; Peng, Xiaojun

    2015-01-01

    Modifying chitosan (CS) with polyethylenimine (PEI) grafts is an effective way to improve its gene transfection performance. However, it is still a challenge to conduct the grafting with fine control and high efficiency, particularly for the modification of water-insoluble CS. Herein, a novel method to graft CS with PEI (1.8 kDa, PEI-1.8) was developed by using ionic liquid 1-butyl-3-methyl imidazolium acetate ([BMIM]Ac) as a reaction solvent, water-insoluble CS as a reaction substrate and 1,1-carbonyldiimidazole (CDI) as a linking agent. The grafting reaction was greatly accelerated and the reaction time was largely shortened to 4 h by taking advantages of the good solubility of CS, the enhanced nucleophilicity of amino groups and the preferential stability of the activated complexes in the ionic liquid. The chitosan-graft-polyethylenimine (CS-g-PEI) products were characterized by 1H NMR, FTIR and GPC. PEI-1.8 was quantitatively grafted to CS through urea linkages, and the grafting degree (GD) was conveniently tuned by varying the molar ratios of PEI-1.8 to D-glucosamine units of CS in the range of 9.0 × 10-3 to 9.0 × 10-2. Compared with CS, the synthesized CS-g-PEI copolymers showed higher pDNA-binding affinity, which increased with the GD as shown in Agarose gel electrophoresis. The dynamic light scattering (DLS) experiment demonstrated that the CS-g-PEI/pDNA polyplexes had suitable particle sizes and proper ζ-potentials for cell transfection. The CS-g-PEI copolymer with a medium GD of 4.5% conferred the best gene transfection, with the efficiency 44 times of CS and 38 times of PEI-1.8 in HEp-2 cells. The cytotoxicity of CS-g-PEI was tested and found nearly as low as that of CS and much lower than that of PEI. PMID:25875475

  15. Grafting chitosan with polyethylenimine in an ionic liquid for efficient gene delivery.

    PubMed

    Chen, Huiying; Cui, Shaohui; Zhao, Yinan; Zhang, Chuanmin; Zhang, Shubiao; Peng, Xiaojun

    2015-01-01

    Modifying chitosan (CS) with polyethylenimine (PEI) grafts is an effective way to improve its gene transfection performance. However, it is still a challenge to conduct the grafting with fine control and high efficiency, particularly for the modification of water-insoluble CS. Herein, a novel method to graft CS with PEI (1.8 kDa, PEI-1.8) was developed by using ionic liquid 1-butyl-3-methyl imidazolium acetate ([BMIM]Ac) as a reaction solvent, water-insoluble CS as a reaction substrate and 1,1-carbonyldiimidazole (CDI) as a linking agent. The grafting reaction was greatly accelerated and the reaction time was largely shortened to 4 h by taking advantages of the good solubility of CS, the enhanced nucleophilicity of amino groups and the preferential stability of the activated complexes in the ionic liquid. The chitosan-graft-polyethylenimine (CS-g-PEI) products were characterized by 1H NMR, FTIR and GPC. PEI-1.8 was quantitatively grafted to CS through urea linkages, and the grafting degree (GD) was conveniently tuned by varying the molar ratios of PEI-1.8 to D-glucosamine units of CS in the range of 9.0 × 10(-3) to 9.0 × 10(-2). Compared with CS, the synthesized CS-g-PEI copolymers showed higher pDNA-binding affinity, which increased with the GD as shown in Agarose gel electrophoresis. The dynamic light scattering (DLS) experiment demonstrated that the CS-g-PEI/pDNA polyplexes had suitable particle sizes and proper ζ-potentials for cell transfection. The CS-g-PEI copolymer with a medium GD of 4.5% conferred the best gene transfection, with the efficiency 44 times of CS and 38 times of PEI-1.8 in HEp-2 cells. The cytotoxicity of CS-g-PEI was tested and found nearly as low as that of CS and much lower than that of PEI.

  16. Oligoethylenimine-grafted chitosan as enhanced T1 contrast agent for in vivo targeted tumor MRI.

    PubMed

    Tong, Xiaoyan; Liu, Min; Zhang, Kunchi; Cao, Yi; Dong, Jingjin; Jiang, Bin; Lu, Bo; Zheng, Hua; Zhang, Hailu; Pei, Renjun

    2016-07-01

    To synthesize and characterize an effective macromolecular magnetic resonance imaging (MRI) contrast agent based on oligoethylenimine-grafted chitosan with targeting capability. In this study we synthesized and characterized oligoethylenimine-grafted chitosan copolymers, followed by conjugating with Gd-DTPA and folic acid. The toxicity was evaluated by WST assay, and in vitro MRI studies were performed in comparison with Gd-DTPA. Finally, the contrast enhancement of the new macromolecular MRI contrast agent was then evaluated in the mice bearing KB xenografts. Compared to Gd-DTPA (4.3 mM(-1) s(-1) ), this macromolecular contrast agent (mCA) exhibited much higher T1 relaxivity (14.4 mM(-1) s(-1) ), up to 3.3 times higher. Meanwhile, the WST assay illustrated that the viability of KB cells remained at 90% even when the Gd concentration was 1 mM. During the in vivo study, the image contrast produced by FA-mCA was higher than one produced by mCA, up to 2.5 times higher. Our results showed this macromolecular contrast agent has potential for developing sensitive and biocompatible MRI probe with targeting capability. J. Magn. Reson. Imaging 2016;44:23-29. © 2015 Wiley Periodicals, Inc.

  17. Radiation grafting of N-vinylcaprolactam onto nano and macrogels of chitosan: Synthesis and characterization.

    PubMed

    Cruz, Angélica; García-Uriostegui, Lorena; Ortega, Alejandra; Isoshima, Takashi; Burillo, Guillermina

    2017-01-02

    The aim of this study was to synthesize chitosan hydrogels, in macro- and nano-size, grafted with N-vinylcaprolactam (NVCL) using gamma radiation, and evaluate their potential application as a drug delivery system, using 5-fluorouracil (5-FU) as a model drug. The effect of dose and monomer concentration in the grafting process was studied, and the materials were characterized by FTIR, TGA, DLS, SEM and AFM. Higher grafting percentages were observed for the nanogels system. Although both the grafted macro- and nanogels, (net-CS)-g-NVCL, showed a response to pH (4.75) and temperature (31-33°C), the nanogels showed a better swelling response to both stimuli because of their higher surface area. Both systems were able to load 5-FU in small amounts (2-3.5mgg(-1)) and the release was sustained for more than 12h, showing that the modified macro and nanogels can be a potential alternative for the administration of drugs. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. Preparation of low molecular weight N-maleated chitosan-graft-PAMAM copolymer for enhanced DNA complexation.

    PubMed

    Sarkar, Kishor; Kundu, P P

    2012-12-01

    Low molecular weight N-maleated chitosan-graft-PAMAM (polyamidoamine) copolymer was prepared through N-maleated chitosan (NMC) by Michael type addition reaction to enhance its solubility in water as well as its cationic character for enhancement of DNA complexation. FTIR, (1)H NMR, XRD and GPC were used to characterize the graft copolymers. The copolymer showed better DNA complexation ability at low N/P ratio than that of chitosan due to increased surface charge density by the incorporation of PAMAM molecule on to chitosan backbone. The copolymer can effectively protect the DNA toward anionic surfactant. In vitro release study showed efficient DNA release occurred at physiological pH (pH 7.4). In vitro cell cytotoxicity test indicated toward less cytotoxicity of NMC-graft-PAMAM copolymers compared to that of 25 kDa PEI. Thus, the synthesized NMC-graft-PAMAM copolymers have great potential of finding application in drug and gene delivery. Copyright © 2012 Elsevier B.V. All rights reserved.

  19. Chitosan-based microcapsules containing grapefruit seed extract grafted onto cellulose fibers by a non-toxic procedure.

    PubMed

    Alonso, Diana; Gimeno, Miquel; Sepúlveda-Sánchez, José D; Shirai, Keiko

    2010-04-19

    A novel non-toxic procedure is described for the grafting of chitosan-based microcapsules containing grapefruit seed oil extract onto cellulose. The cellulose was previously UV-irradiated and then functionalized from an aqueous emulsion of the chitosan with the essential oil. The novel materials are readily attained with durable fragrance and enhanced antimicrobial properties. The incorporation of chitosan as determined from the elemental analyses data was 16.08+/-0.29 mg/g of sample. Scanning electron microscopy (SEM) and gas chromatography-mass spectroscopy (GC-MS) provided further evidence for the successful attachment of chitosan microcapsules containing the essential oil to the treated cellulose fibers. The materials thus produced displayed 100% inhibition of Escherichia coli and Staphylococcus epidermidis up to 48 h of incubation. Inhibition of bacteria by the essential oil was also evaluated at several concentrations.

  20. Biocompatible and biodegradable ultrafine fibrillar scaffold materials for tissue engineering by facile grafting of L-lactide onto chitosan.

    PubMed

    Skotak, Maciej; Leonov, Alexei P; Larsen, Gustavo; Noriega, Sandra; Subramanian, Anuradha

    2008-07-01

    A chitosan derivative was prepared with good yields using a "one pot" approach by grafting L-lactide oligomers via ring opening polymerization. Side chains are primarily attached to hydroxyl groups located on carbons 3 and 6 of the glucosamine ring, while the amine group remains nonfunctionalized. By increasing the L-lactide to chitosan ratio, side chain length is controlled. This allows the manipulation of the biodegradation rate and hydrophilicity of the tissue engineering scaffold material. This general synthetic route renders functionalized chitosan soluble in a broad range of organic solvents, facilitating formation of ultrafine fibers via electrospinning. Cytotoxicity tests using fibroblasts (L929 cell line) performed on electrospun L-lactide modified chitosan fibers showed that the specimen with the highest molar ratio of L-lactide (1:24) investigated in this study is the most promising material for tissue engineering purposes, while less stable formulations might still find application in drug delivery vehicles.

  1. Cross-linking of succinate-grafted chitosan and its effect on the capability to adsorb Pb(II) ion

    NASA Astrophysics Data System (ADS)

    Masykur, Abu; Juari Santosa, Sri; Jumina, Dwi Siswanta dan

    2016-02-01

    The aim of this research was to improve the adsorption capacity of chitosan by modification of the chitosan using various cross-linking agents and followed by grafting using succinate anhydride. Succinate anhydride was grafted into chitosan that had been cross-linked using ethylene glycol di-glycidyl ether (EGDE), diethylene glycol diglycidyl ether (DEGDE) andbisphenolAdiglycidyl ether (BADGE) on the hydroxyl group of chitosan to yield Chit- EGDE-Suc, Chit-DEGDE-Suc, and Chit-BADGE-Suc, respectively. Modified chitosans were analyzed using FTIR and TG-DTA and then applied as adsorbents for Pb(II) ion. Adsorption was carried out in batch condition with a variation of solution pH, contact time, and concentration of Pb(II) in the solution. Adsorption ofPb(II) ion reached optimum condition at pH 5 and contact time of 120 minutes. Adsorption of Pb(II) ion on all of the adsorbents fit well the pseudo-second order kinetic equation. Adsorption capacities of Pb(II) on Chit-EGDE-Suc, Chit-DEGDE-SucdanChit-BADGE-Suc were 0.333, 0.388 and 0.898 mmolg-1, respectively, which mean that the adsorption of Chit-BADGE-Suc was the highest and followed by Chit- DEGDE-Suc and Chit-EGDE-Suc.

  2. Chitosan Grafted with Phosphorylcholine and Macrocyclic Polyamine as an Effective Gene Delivery Vector: Preparation, Characterization and In Vitro Transfection.

    PubMed

    Li, Ling; Zhao, Fangfang; Zhao, Baojing; Zhang, Jin; Li, Chao; Qiao, Renzhong

    2015-07-01

    Herein, an effective gene delivery vector phosphorylcholine and macrocyclic polyamine grafted chitosan (PC-g(6)-Cs-g(2)-Cyclen) was developed. Chemical characterization of product PC-g(6)-Cs-g(2)-Cyclen was performed by NMR, FT-IR, gel permeation chromatography (GPC), and X-ray photoelectron spectroscopy (XPS) analysis. PC-g(6)-Cs-g(2)-Cyclen could more efficiently bind and protect plasmid DNA than macrocyclic polyamine grafted chitosan (Cs-g-Cyclen) and phosphorylcholine grafted chitosan (Cs-g-PC), as evaluated by agarose gel electrophoresis, circular dichroism spectra, and fluorescence quenching assays. PC-g(6)-Cs-g(2)-Cyclen could wrap DNA into uniform nanoparticles in the size of 112.6 ± 8.5 nm and possessed net cationic charge. UV spectroscopy and MTT assays showed excellent water-solubility and cell viability for PC-g(6)-Cs-g(2)-Cyclen. In addition, three polymer/DNA complexes showed 5.1-15.1-fold greater uptake activity and 10-14-fold higher transfection efficiency in 293 T cells as compared to chitosan/DNA complex, in which PC-g(6)-Cs-g(2)-Cyclen demonstrated the highest transfection activity. These date demonstrated that PC-g(6)-Cs-g(2)-Cyclen is a promising vector candidate for gene delivery.

  3. Hypromellose-graft-chitosan and Its Polyelectrolyte Complex as Novel Systems for Sustained Drug Delivery.

    PubMed

    Lai, Wing-Fu; Shum, Ho Cheung

    2015-05-20

    Polyelectrolyte complexes formed between chitosan (CS) and anionic polymers have attracted increasing interest in drug delivery. In this study, CS is copolymerized with hypromellose via a coupling reagent-mediated approach to form a water-soluble, nontoxic CS derivative, namely hypromellose-graft-CS (HC), which is subsequently complexed with carboxymethylcellulose (CMC) to generate a polyampholytic hydrogel. When compared with conventional CS, HC is highly water-soluble across a wide pH range, and has a substantially higher pH buffering capacity to provide a pH-stable environment for delivery of drugs. In addition, the polyelectrolyte complex of HC exhibits a drug encapsulation efficiency of over 90% in all drugs tested, which is 1-2 fold higher than the efficiency attainable by the polyelectrolyte complex of conventional CS, with a 2-3 fold longer duration of sustained drug release. Our results indicate that as a novel polymer, HC has excellent promise for future pharmaceutical applications.

  4. Design and formulation of trimethylated chitosan-graft-poly(ε-caprolactone) nanoparticles used for gene delivery.

    PubMed

    Tang, San; Huang, Zhixiong; Zhang, Haiwen; Wang, Youxiang; Hu, Qiaoling; Jiang, Hongliang

    2014-01-30

    The ideal gene polyplexes should have a subtle balance between polyplex stability to protect DNA against nucleases, and polyplex instability to permit DNA dissociation inside cells. In this research, low molecular weight trimethylated chitosan was chemically modified with poly(ε-caprolactone). Owing to the amphiphilic character, trimethylated chitosan-graft-poly(ε-caprolactone) (TMC-g-PCL) formed nanoparticles in aqueous media. TMC-g-PCL nanoparticles could effectively condense pDNA into polyplexes about 200 nm in size. The TMC-g-PCL/DNA polyplexes were stable in physiological salt condition and showed high uptake efficiency probably due to the increasing cell membrane-carrier interaction as a result of hydrophobic modification. However, the high degree of quaternization influenced the buffer capacity of TMC-g-PCL and led to a reduction in the release from the lysosomes. By adding chloroquine to exclude the limitation of lysosome escape, the transfection efficiency of TMC-g-PCL/DNA polyplexes was similar to that of PEI/DNA polyplexes. This study demonstrated the potential of TMC-g-PCL/DNA nanoparticles as an efficient carrier for gene delivery.

  5. Silver deposited carboxymethyl chitosan-grafted magnetic nanoparticles as dual action deliverable antimicrobial materials.

    PubMed

    Vo, Duc-Thang; Sabrina, Sabrina; Lee, Cheng-Kang

    2017-04-01

    Carboxymethyl chitosan (CMCS) was known to have a much better antimicrobial activity than chitosan due to the increased cationic -NH3(+) groups resulted from the intra- and intermolecular interactions between the carboxyl and amino groups. CMCS was grafted onto the surface of silica coated magnetic nanoparticles (MNPs) to obtain magnetically retrievable and deliverable antimicrobial nanoparticles (MNPs@CMCS). The presence of carboxylate groups in CMCS not only enhanced antimicrobial activity but also enabled Ag ions chelating ability to induce the in situ formation of Ag nanoparticles (AgNPs). The deposition of AgNPs on the surface of MNPs@CMCS could significantly increase its antimicrobial activity against planktonic cells due to the dual action of CMCS and AgNPs. Due to its high magnetism, the as-prepared MNPs@CMCS-Ag could be efficiently delivered into an existing biofilm under the guidance of an applied magnetic field. Without direct contact, the Ag ions and/or radical oxygen species (ROS) released from the deposited Ag nanoparticles could effectively kill the bacteria embedded in the extracellular polymeric substances (EPS) matrix of biofilm.

  6. Deoxycholic acid-grafted PEGylated chitosan micelles for the delivery of mitomycin C.

    PubMed

    Zhang, Xiu-Rong; Shi, Nian-Qiu; Zhao, Yang; Zhu, He-Yun; Guan, Jiao; Jin, Ying

    2015-06-01

    Mitomycin C (MTC) was incorporated to a micelle system preparing from a polymer named deoxycholic acid chitosan-grafted poly(ethylene glycol) methyl ether (mPEG-CS-DA). mPEG-CS-DA was synthesized and characterized by (1)H nuclear magnetic resonance ((1)H-NMR) and Fourier transform infrared spectroscopy. mPEG-CS-DA formed a core-shell micellar structure with a critical micelle concentration of 6.57 µg/mL. The mPEG-CS-DA micelles were spherical with a hydrodynamic diameter of about 231 nm. After poly(ethylene glycol)ylation of deoxycholic acid chitosan (CS-DA), the encapsulation efficiency and drug loading efficiency increased from 50.62% to 56.42% and from 20.51% to 24.13%, respectively. The mPEG-CS-DA micelles possessed a higher drug release rate than the CS-DA micelles. For pharmacokinetics, the area under the curve (AUC) of the mPEG-CS-DA micelles was 1.5 times higher than that of MTC injection, and these micelles can enhance the bioavailability of MTC. mPEG-CS-DA micelles reduced the distribution of MTC in almost all normal tissues and had the potential to improve the kidney toxicity caused by MTC injection.

  7. Electrospun collagen-chitosan-TPU nanofibrous scaffolds for tissue engineered tubular grafts.

    PubMed

    Huang, Chen; Chen, Rui; Ke, Qinfei; Morsi, Yosry; Zhang, Kuihua; Mo, Xiumei

    2011-02-01

    The objective of this study is to design a novel kind of scaffolds for blood vessel and nerve repairs. Random and aligned nanofibrous scaffolds based on collagen-chitosan-thermoplastic polyurethane (TPU) blends were electrospun to mimic the componential and structural aspects of the native extracellular matrix, while an optimal proportion was found to keep the balance between biocompatibility and mechanical strength. The scaffolds were crosslinked by glutaraldehyde (GTA) vapor to prevent them from being dissolved in the culture medium. Fiber morphology was characterized using scanning electron microscopy (SEM) and atomic-force microscopy (AFM). Fourier transform infrared spectroscopy (FTIR) showed that the three-material system exhibits no significant differences before and after crosslinking, whereas pore size of crosslinked scaffolds decreased drastically. The mechanical properties of the scaffolds were found to be flexible with a high tensile strength. Cell viability studies with endothelial cells and Schwann cells demonstrated that the blended nanofibrous scaffolds formed by electrospinning process had good biocompatibility and aligned fibers could regulate cell morphology by inducing cell orientation. Vascular grafts and nerve conduits were electrospun or sutured based on the nanofibrous scaffolds and the results indicated that collagen-chitosan-TPU blended nanofibrous scaffolds might be a potential candidate for vascular repair and nerve regeneration. Copyright © 2010 Elsevier B.V. All rights reserved.

  8. Prevention of peritendinous adhesions with electrospun chitosan-grafted polycaprolactone nanofibrous membranes.

    PubMed

    Chen, Shih-Hsien; Chen, Chih-Hao; Fong, Yi Teng; Chen, Jyh-Ping

    2014-12-01

    As one of the common complications after tendon injury and subsequent surgery, peritendinous adhesions could be minimized by directly placing a physical barrier between the injured site and the surrounding tissue. With the aim of solving the shortcomings of current biodegradable anti-adhesion barrier membranes, we propose the use of an electrospun chitosan-grafted polycaprolactone (PCL-g-CS) nanofibrous membrane (NFM) to prevent peritendinous adhesions. After introducing carboxyl groups on the surface by oxygen plasma treatment, the polycaprolactone (PCL) NFM was covalently grafted with chitosan (CS) molecules, with carbodiimide as the coupling agent. Compared with PCL NFM, PCL-g-CS NFM showed a similar fiber diameter, permeation coefficient for bovine serum albumin, ultimate tensile strain, reduced pore diameter, lower water contact angle, increased water sorption and tensile strength. With its submicrometer pore diameter (0.6-0.9μm), both NFMs could allow the diffusion of nutrients and waste while blocking fibroblast penetration to prevent adhesion formation after tendon surgery. Cell culture experiments verified that PCL-g-CS NFM can reduce fibroblast attachment while maintaining the biocompatibility of PCL NFM, implicating a synergistic anti-adhesion effect to raise the anti-adhesion efficacy. In vivo studies with a rabbit flexor digitorum profundus tendon surgery model confirmed that PCL-g-CS NFM effectively reduced peritendinous adhesion from gross observation, histology, joint flexion angle, gliding excursion and biomechanical evaluation. An injured tendon wrapped with PCL-g-CS NFM showed the same tensile strength as the naturally healed tendon, indicating that the anti-adhesion NFM will not compromise tendon healing. Copyright © 2014 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  9. Chitosan-graft-polyethylenimine/DNA nanoparticles as novel non-viral gene delivery vectors targeting osteoarthritis.

    PubMed

    Lu, Huading; Dai, Yuhu; Lv, Lulu; Zhao, Huiqing

    2014-01-01

    The development of safe and efficient gene carriers is the key to the clinical success of gene therapy. The present study was designed to develop and evaluate the chitosan-graft-polyethylenimine (CP)/DNA nanoparticles as novel non-viral gene vectors for gene therapy of osteoarthritis. The CP/DNA nanoparticles were produced through a complex coacervation of the cationic polymers with pEGFP after grafting chitosan (CS) with a low molecular weight (Mw) PEI (Mw = 1.8 kDa). Particle size and zeta potential were related to the weight ratio of CP:DNA, where decreases in nanoparticle size and increases in surface charge were observed as CP content increased. The buffering capacity of CP was significantly greater than that of CS. The transfection efficiency of CP/DNA nanoparticles was similar with that of the Lipofectamine™ 2000, and significantly higher than that of CS/DNA and PEI (25 kDa)/DNA nanoparticles. The transfection efficiency of the CP/DNA nanoparticles was dependent on the weight ratio of CP:DNA (w/w). The average cell viability after the treatment with CP/DNA nanoparticles was over 90% in both chondrocytes and synoviocytes, which was much higher than that of PEI (25 kDa)/DNA nanoparticles. The CP copolymers efficiently carried the pDNA inside chondrocytes and synoviocytes, and the pDNA was detected entering into nucleus. These results suggest that CP/DNA nanoparticles with improved transfection efficiency and low cytotoxicity might be a safe and efficient non-viral vector for gene delivery to both chondrocytes and synoviocytes.

  10. Microwave assisted preparation of n-butylacrylate grafted chitosan and its application for Cr(VI) adsorption.

    PubMed

    Santhana Krishna Kumar, A; Uday Kumar, Chinta; Rajesh, Vidya; Rajesh, N

    2014-05-01

    Biopolymers such as chitosan possess excellent properties suited for varied applications. In this work, we describe a novel microwave assisted method for the preparation of n-butylacrylate grafted chitosan adsorbent and its utility for the adsorption of chromium(VI). A 3 min irradiation time was enough to prepare the adsorbent, and techniques such as FT-IR, powder XRD, SEM and EDS were used for comprehensive characterization. The adsorption was effective at pH 3.5 with 25 mL of 20 ppm Cr(VI) solution. Langmuir, Freundlich, Dubinin-Radushkevich, Temkin, Elovich and Redlich isotherms were studied in detail. The ΔG, ΔH and ΔS parameters were evaluated to understand the adsorption thermodynamics. The adsorption involves the interaction of Cr(VI) with the hydroxyl and amino groups in chitosan. Copyright © 2014 Elsevier B.V. All rights reserved.

  11. Comparison of results between chitosan hollow tube and autologous nerve graft in reconstruction of peripheral nerve defect: An experimental study.

    PubMed

    Shapira, Yuval; Tolmasov, Michael; Nissan, Moshe; Reider, Evgeniy; Koren, Akiva; Biron, Tali; Bitan, Yifat; Livnat, Mira; Ronchi, Giulia; Geuna, Stefano; Rochkind, Shimon

    2016-11-01

    This study evaluated a chitosan tube for regeneration of the injured peripheral nerve in a rodent transected sciatic nerve model in comparison to autologous nerve graft repair. Chitosan hollow tube was used to bridge a 10-mm gap between the proximal and distal ends in 11 rats. In the control group, an end-to-end coaptation of 10-mm long autologous nerve graft was performed in 10 rats for nerve reconstruction. SFI showed an insignificant advantage to the autologous group both at 30 days (P = 0.177) and at 90 days post procedure (P = 0.486). Somato-sensory evoked potentials (SSEP) and compound muscle action potentials (CMAP) tests showed similar results between chitosan tube (group 1) and autologous (group 2) groups with no statistically significant differences. Both groups presented the same pattern of recovery with 45% in group 1 and 44% in group 2 (P = 0.96) showing SSEP activity at 30 days. At 90 days most rats showed SSEP activity (91% vs.80% respectively, P = 0.46). The CMAP also demonstrated no statistically significant differences in latency (1.39 ms in group 1 vs. 1.63 ms in group 2; P = 0.48) and amplitude (6.28 mv vs. 6.43 mv respectively; P = 0.8). Ultrasonography demonstrated tissue growth inside the chitosan tube. Gastrocnemius muscle weight showed no statistically significant difference. Histomorphometry of the distal sciatic nerve, 90 days post reconstructive procedure, showed similar number of myelinated fibers and size parameters in both groups (P ≥ 0.05). Chitosan hollow tube used for peripheral nerve reconstruction of rat sciatic nerve showed similar results in comparison to autologous nerve grafting. © 2015 Wiley Periodicals, Inc. Microsurgery 36:664-671, 2016. © 2015 Wiley Periodicals, Inc.

  12. Removal of dorzolamide from biomedical wastewaters with adsorption onto graphite oxide/poly(acrylic acid) grafted chitosan nanocomposite.

    PubMed

    Kyzas, George Z; Bikiaris, Dimitrios N; Seredych, Mykola; Bandosz, Teresa J; Deliyanni, Eleni A

    2014-01-01

    A novel graphite oxide/poly(acrylic acid) grafted chitosan nanocomposite (GO/CSA) was prepared and used as biosorbent for the removal of pharmaceutical compound (dorzolamide) from biomedical synthetic wastewaters. The performance was evaluated taking into account pH, kinetics and thermodynamics of adsorption. GO/CSA presented higher adsorption capacity in comparison with the parent materials (graphite oxide and poly(acrylic acid) grafted chitosan). All adsorbents prepared were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and potentiometric titration. The surface features were also evaluated after the dorzolamide adsorption in order to derive the adsorption mechanism. It was suggested that the reactive groups of GO and CSA can interact with the amino groups of dorzolamide and mainly the abundance of carboxyl groups of GO/CSA composite was the main reason for its enhanced adsorption capacity. Copyright © 2013 Elsevier Ltd. All rights reserved.

  13. Radiation-induced graft copolymerization of poly(ethylene glycol) monomethacrylate onto deoxycholate-chitosan nanoparticles as a drug carrier

    NASA Astrophysics Data System (ADS)

    Pasanphan, Wanvimol; Rattanawongwiboon, Thitirat; Rimdusit, Pakjira; Piroonpan, Thananchai

    2014-01-01

    Poly(ethylene glycol) monomethacrylate-grafted-deoxycholate chitosan nanoparticles (PEGMA-g-DCCSNPs) were successfully prepared by radiation-induced graft copolymerization. The hydrophilic poly(ethylene glycol) monomethacrylate was grafted onto deoxycholate-chitosan in an aqueous system. The radiation-absorbed dose is an important parameter on degree of grafting, shell thickness and particle size of PEGMA-g-DCCSNPs. Owing to their amphiphilic architecture, PEGMA-g-DCCSNPs self-assembled into spherical core-shell nanoparticles in aqueous media. The particle size of PEGMA-g-DCCSNPs measured by TEM varied in the range of 70-130 nm depending on the degree of grafting as well as the irradiation dose. Berberine (BBR) as a model drug was encapsulated into the PEGMA-g-DCCSNPs. Drug release study revealed that the BBR drug was slowly released from PEGMA-g-DCCSNPs at a mostly constant rate of 10-20% in PBS buffer (pH 7.4) at 37 °C over a period of 23 days.

  14. Design of Chitosan-Grafted Carbon Nanotubes: Evaluation of How the –OH Functional Group Affects Cs+ Adsorption

    PubMed Central

    Yang, Shubin; Shao, Dadong; Wang, Xiangke; Hou, Guangshun; Nagatsu, Masaaki; Tan, Xiaoli; Ren, Xuemei; Yu, Jitao

    2015-01-01

    In order to explore the effect of –OH functional groups in Cs+ adsorption, we herein used the low temperature plasma-induced grafting method to graft chitosan onto carbon nanotubes (denoted as CTS-g-CNTs), as raw-CNTs have few functional groups and chitosan has a large number of –OH functional groups. The synthesized CTS-g-CNT composites were characterized using different techniques. The effect of –OH functional groups in the Cs+ adsorption process was evaluated by comparison of the adsorption properties of raw-CNTs with and without grafting chitosan. The variation of environmental conditions such as pH and contact time was investigated. A comparison of contaminated seawater and simulated groundwater was also evaluated. The results indicated that: (1) the adsorption of Cs+ ions was strongly dependent on pH and the competitive cations; (2) for CNT-based material, the –OH functional groups have a positive effect on Cs+ removal; (3) simulated contaminated groundwater can be used to model contaminated seawater to evaluate the adsorption property of CNTs-based material. These results showed direct observational evidence on the effect of –OH functional groups for Cs+ adsorption. Our findings are important in providing future directions to design and to choose effective material to remedy the removal of radioactive cesium from contaminated groundwater and seawater, crucial for public health and the human social environment. PMID:26006711

  15. Glial cell line-derived neurotrophic factor gene delivery via a polyethylene imine grafted chitosan carrier.

    PubMed

    Peng, Yu-Shiang; Lai, Po-Liang; Peng, Sydney; Wu, His-Chin; Yu, Siang; Tseng, Tsan-Yun; Wang, Li-Fang; Chu, I-Ming

    2014-01-01

    Parkinson's disease is known to result from the loss of dopaminergic neurons. Direct intracerebral injections of high doses of recombinant glial cell line-derived neurotrophic factor (GDNF) have been shown to protect adult nigral dopaminergic neurons. Because GDNF does not cross the blood-brain barrier, intracerebral gene transfer is an ideal option. Chitosan (CHI) is a naturally derived material that has been used for gene transfer. However, the low water solubility often leads to decreased transfection efficiency. Grafting of highly water-soluble polyethylene imines (PEI) and polyethylene glycol onto polymers can increase their solubility. The purpose of this study was to design a non-viral gene carrier with improved water solubility as well as enhanced transfection efficiency for treating Parkinsonism. Two molecular weights (Mw =600 and 1,800 g/mol) of PEI were grafted onto CHI (PEI600-g-CHI and PEI1800-g-CHI, respectively) by opening the epoxide ring of ethylene glycol diglycidyl ether (EX-810). This modification resulted in a non-viral gene carrier with less cytotoxicity. The transfection efficiency of PEI600-g-CHI/deoxyribonucleic acid (DNA) polyplexes was significantly higher than either PEI1800-g-CHI/DNA or CHI/DNA polyplexes. The maximal GDNF expression of PEI600-g-CHI/DNA was at the polymer:DNA weight ratio of 10:1, which was 1.7-fold higher than the maximal GDNF expression of PEI1800-g-CHI/DNA. The low toxicity and high transfection efficiency of PEI600-g-CHI make it ideal for application to GDNF gene therapy, which has potential for the treatment of Parkinson's disease.

  16. Glial cell line-derived neurotrophic factor gene delivery via a polyethylene imine grafted chitosan carrier

    PubMed Central

    Peng, Yu-Shiang; Lai, Po-Liang; Peng, Sydney; Wu, His-Chin; Yu, Siang; Tseng, Tsan-Yun; Wang, Li-Fang; Chu, I-Ming

    2014-01-01

    Parkinson’s disease is known to result from the loss of dopaminergic neurons. Direct intracerebral injections of high doses of recombinant glial cell line-derived neurotrophic factor (GDNF) have been shown to protect adult nigral dopaminergic neurons. Because GDNF does not cross the blood–brain barrier, intracerebral gene transfer is an ideal option. Chitosan (CHI) is a naturally derived material that has been used for gene transfer. However, the low water solubility often leads to decreased transfection efficiency. Grafting of highly water-soluble polyethylene imines (PEI) and polyethylene glycol onto polymers can increase their solubility. The purpose of this study was to design a non-viral gene carrier with improved water solubility as well as enhanced transfection efficiency for treating Parkinsonism. Two molecular weights (Mw =600 and 1,800 g/mol) of PEI were grafted onto CHI (PEI600-g-CHI and PEI1800-g-CHI, respectively) by opening the epoxide ring of ethylene glycol diglycidyl ether (EX-810). This modification resulted in a non-viral gene carrier with less cytotoxicity. The transfection efficiency of PEI600-g-CHI/deoxyribonucleic acid (DNA) polyplexes was significantly higher than either PEI1800-g-CHI/DNA or CHI/DNA polyplexes. The maximal GDNF expression of PEI600-g-CHI/DNA was at the polymer:DNA weight ratio of 10:1, which was 1.7-fold higher than the maximal GDNF expression of PEI1800-g-CHI/DNA. The low toxicity and high transfection efficiency of PEI600-g-CHI make it ideal for application to GDNF gene therapy, which has potential for the treatment of Parkinson’s disease. PMID:25061293

  17. The highly effective removal of Cs⁺ by low turbidity chitosan-grafted magnetic bentonite.

    PubMed

    Yang, Shubin; Okada, Naoya; Nagatsu, Masaaki

    2016-01-15

    Chitosan-grafted magnetic bentonite (CS-g-MB) was successfully synthesized via a plasma-induced method. The CS-g-MB composite shows good magnetic properties, low turbidity, and high stability in aqueous solution and exhibits significant adsorption capacity for Cs(+) ions. The adsorption of Cs(+) by CS-g-MB is dependent on both pH and ionic strength. In the presence of Mg(2+), K(+), Li(+), and Na(+) ions, the Cs(+) exchange is constrained in the order of Li(+)≈Mg(2+)

  18. Biosorption of palladium(II) from aqueous solution by grafting chitosan on persimmon tannin extract.

    PubMed

    Zhou, Zhide; Liu, Fenglei; Huang, Yong; Wang, Zhongmin; Li, Guiyin

    2015-01-01

    A low-cost and environmentally green biosorbent (PTCS) was prepared by grafting chitosan onto persimmon tannin extract and its potentiality for efficient adsorption of palladium ion (Pd(II)) from aqueous solution was evaluated. Various adsorption parameters such as pH, the initial Pd(II) concentration and temperature were investigated. The maximum adsorption capacity reached 330mg/g at 323K and pH 5.0 when the initial Pd(II) concentration was 100mg/L. The equilibrium adsorption data were satisfactorily fitted with Freundlich isotherm model and biosorption kinetics was found to be in good agreement with pseudo-second-order kinetics model. Thermodynamic calculations indicated that the adsorption process was endothermic and spontaneous in nature because of the negative value of free energy change (ΔG) and positive value of enthalpy change (ΔH). The positive value of entropy change (ΔS) revealed the increased randomness at the solid-liquid interface. FT-IR and XRD analysis verified that Pd(II) adsorption on PTCS was electrostatic interaction and redox reaction. Moreover, selective adsorption study revealed that the adsorbent exhibited good adsorption ability to Pd(II) in the mixture metal ions solutions. All these results indicated that the PTCS biosorbent could be used as a low-cost alternative for the adsorption of Pd(II) in waste-water treatment. Copyright © 2015 Elsevier B.V. All rights reserved.

  19. Reactive blending of thermoplastic starch and polyethylene-graft-maleic anhydride with chitosan as compatibilizer.

    PubMed

    Jantanasakulwong, Kittisak; Leksawasdi, Noppol; Seesuriyachan, Phisit; Wongsuriyasak, Somchai; Techapun, Charin; Ougizawa, Toshiaki

    2016-11-20

    Cassava starch was melt-blended with glycerol (70/30wt%/wt%) at 140°C to prepare thermoplastic starch (TPS). Chitosan (CTS) was premixed with starch and glycerol, in acidified water (lactic acid 2wt%), at 1, 5 and 10wt%/wt%. TPS/CTS was then melt-blended (160°C) with polyethylene-graft-maleic anhydride (PE-MAH). Phase determination and scanning electron microscopy indicated TPS/PE-MAH/CTS had a co-continuous morphology and CTS-induced phase inversion to give dispersed PE-MAH particles in a TPS matrix. Tensile strength at break and elongation, melt viscosity, fracture toughness and water contact angle of TPS/PE-MAH were improved by CTS incorporation. TPS/PE-MAH/CTS blends decreased the melting temperature of TPS and PE-MAH compared to the neat polymers. FTIR confirmed a reaction had occurred between amino groups (NH2) of CTS and the MAH groups of PE-MAH. This reaction and the enhanced miscibility between TPS and CTS improved the mechanical properties of the TPS/PE-MAH/CTS blend, particularly at 5wt%/wt% CTS. Copyright © 2016 Elsevier Ltd. All rights reserved.

  20. Preparation, Characterization, and Insecticidal Activity of Avermectin-Grafted-Carboxymethyl Chitosan

    PubMed Central

    Li, Yan; Qin, Yukun; Liu, Song; Xing, Ronge; Yu, Huahua; Li, Kecheng; Li, Pengcheng

    2016-01-01

    Avermectin-grafted-N,O-carboxymethyl chitosan (NOCC) derivative was obtained by esterification reaction using dicyclohexylcarbodiimide (DCC) as dehydrating agent and 4-methylaminopyridine as catalyst. The structures of the conjugate were confirmed by FT-IR, 1H NMR, and XRD. Insecticidal activities against armyworms, carmine spider mites, black bean aphids, and brown plant hoppers were investigated at concentrations ranging from 0.16 to 1000 mg/L. At the concentration of 1000 mg/L and 500 mg/L, the lethal rate was 100%. Good insecticidal activity at 4 mg/L was still shown, especially against the black bean aphids and brown plant hoppers. Moreover, the photostability of the conjugate was evaluated and showed an apparent improvement. At 300 mins, the residual rate of the conjugate was 11.22%, much higher than 0.2% of the avermectin technical material. The conjugate we developed showed potential for further study and application in crop protection. PMID:27213156

  1. Stimuli-sensitive hollow spheres from chitosan-graft-β-cyclodextrin for controlled drug release.

    PubMed

    Yu, Nana; Li, Guiying; Gao, Yurong; Liu, Xunyong; Ma, Songmei

    2016-12-01

    In this paper, sensitive polymeric hollow spheres self-assembled from chitosan-grafted-β-cyclodextrin (CS-g-CD) and sodium tripolyphosphate (TPP) were prepared for controlled release of doxorubicin (DOX). The assemblies were formed by electrostatic interactions between positively charged amino group in CS-g-CD and negatively charged phosphate in TPP. The hollow spheres with diameters about 100nm were confirmed by transmission electron microscopy (TEM) and laser particle analyzer. The microspheres with hollow cavity were beneficial to improve the drug loading capacity for DOX with entrapment efficiency above 60%. The cumulative release of DOX from CS-g-CD/TPP hollow microspheres increased with the decrease of pH and the increase of temperature or ionic strength. At 37 °C and pH 5.2, the maximum drug release was above 90% with a continuous release rate. In-vitro cytotoxicity tests indicate that drug loaded hollow spheres exhibited evidently inhibition against cancer cells. These sensitive polymeric hollow spheres are expected to be used in biomedical field as potential carrier. Copyright © 2016 Elsevier B.V. All rights reserved.

  2. Preparation, characterization, and oral delivery of insulin loaded carboxylated chitosan grafted poly(methyl methacrylate) nanoparticles.

    PubMed

    Cui, Fuying; Qian, Feng; Zhao, Ziming; Yin, Lichen; Tang, Cui; Yin, Chunhua

    2009-05-11

    To improve the efficiency of insulin via oral administration, pH-sensitive carboxylated chitosan grafted poly(methyl methacrylate) nanoparticles (CCGN) were prepared. CCGN were characterized by (1)H NMR, dynamic light scattering, zeta potential, and transmission electron microscopy, and the hypoglycemic effect of insulin loaded CCGN via the oral route was evaluated in normal and diabetic rats. CCGN exhibited a homogeneous morphology and a spherical shape with core-shell structure. They were aggregated in simulated gastric fluid while separated in simulated intestinal fluid. Insulin was mainly located in the shell of the CCGN via hydrogen bonding, electrostatic interaction, and Van der Waals force. Insulin release from the CCGN exhibited a pH-sensitive property in that it had a slow release rate at pH 2.0 and a fast release rate at pH 6.8 and 7.4. The pharmacological bioavailability after oral administration of insulin loaded CCGN at a dose of 25 IU/kg was found to be 9.7%. Besides, CCGN showed desirable tissue and blood compatibility. Therefore, the CCGN would be a promising delivery carrier for protein drugs via the oral route.

  3. Adsorption of uranium by amidoximated chitosan-grafted polyacrylonitrile, using response surface methodology.

    PubMed

    Xu, Chao; Wang, Jingjing; Yang, Tilong; Chen, Xia; Liu, Xunyue; Ding, Xingcheng

    2015-05-05

    The amidoximated chitosan-grafted polyacrylonitrile (CTS-g-PAO) was prepared for the adsorption of uranium from water. The effects of pH, concentration of uranium and the solid-liquid ratio on the adsorption of uranium by CTS-g-PAO were optimized using Doehlert design of response surface methodology (RSM). The adsorption capacity and removal efficiency achieved 312.06 mg/g and 86.02%, respectively. The adsorption process attained equilibrium only in 120 min. More than 80% of the absorbed uranium could be desorbed by 0.1 mol/l HCl or EDTA-Na, and CTS-g-PAO could be reused at least 3 times. The CTS-g-PAO and U(VI) ions formed a chelate complex due to FTIR spectral analysis. The surface morphology of CTS-g-PAO was also investigated by SEM. The adsorption process was better described by Langmuir isotherm and pseudo second order kinetic model. Results obtained indicated that CTS-g-PAO was very promising in adsorption of uranium from water.

  4. Arsenic remediation from drinking water by synthesized nano-alumina dispersed in chitosan-grafted polyacrylamide.

    PubMed

    Saha, Suparna; Sarkar, Priyabrata

    2012-08-15

    An arsenic adsorbent comprising alumina nanoparticles dispersed in polymer matrix was developed and its removal potential studied. Alumina nanoparticles were prepared by reverse microemulsion technique and these were immobilized on chitosan grafted polyacrylamide matrix by in situ dispersion. The loading capacity of this new synthesized adsorbent was found to be high (6.56 mg/g). Batch adsorption studies were performed as a function of contact time, initial arsenic concentration, pH and presence of competing anions. The removal was found to be pH dependent, and maximum removal was obtained at pH 7.2 while the equilibrium time was 6h. The equilibrium adsorption data fitted very well with Freundlich isotherm. However, the D-R isotherm studies indicated that chemisorptions might play an important role. This was also confirmed by the FTIR study of the arsenic loaded adsorbent. A mechanism of arsenic sorption by the new polymeric adsorbent has been proposed. The regeneration study of the adsorbent resulted in retention of 94% capacity in the fifth cycle. An optimum pH of 7.2, operation at normal temperature, high adsorption capacity and good recycle potential of this new adsorbent would make it an ideal material for removal of arsenic from drinking water.

  5. Grafting of aniline derivatives onto chitosan and their applications for removal of reactive dyes from industrial effluents.

    PubMed

    Abbasian, Mojtaba; Jaymand, Mehdi; Niroomand, Pouneh; Farnoudian-Habibi, Amir; Karaj-Abad, Saber Ghasemi

    2017-02-01

    A series of chitosan-grafted polyaniline derivatives {chitosan-g-polyaniline (CS-g-PANI), chitosan-g-poly(N-methylaniline) (CS-g-PNMANI), and chitosan-g-poly(N-ethylaniline) (CS-g-PNEANI)} were synthesized by in situ chemical oxidation polymerization method. The synthesized copolymers were analyzed by means of Fourier transform infrared (FTIR), and ultraviolet-visible (UV-vis) spectroscopies, thermogravimetric analysis (TGA), and field emission scanning electron microscopy (FE-SEM). These copolymers were applied as adsorbent for removal of acid red 4 (AR4) and direct red 23 (DR23) from aqueous solutions. The adsorption processes were optimized in terms of pH, adsorbent amount, and dyes concentrations. The maximum adsorption capacities (Qm) for the synthesized copolymers were calculated, and among them the CS-g-PNEANI sample showed highest Qm for both AR4 (98mgg(-1)) and DR23 (112mgg(-1)) dyes. The adsorption kinetics of AR4 and DR23 dyes follow the pseudo-second order kinetic model. The regeneration and reusability tests revealed that the synthesized adsorbents had the relatively good reusability after five repetitions of the adsorption-desorption cycles. As the results, it is expected that the CS-g-PANIs find application for removal of reactive dyes (especially anionic dyes) from industrial effluents mainly due to their low production costs and high adsorption effectiveness. Copyright © 2016 Elsevier B.V. All rights reserved.

  6. Chitosan

    PubMed Central

    Smith, Alan; Perelman, Michael; Hinchcliffe, Michael

    2014-01-01

    The nasal route is attractive for the delivery of vaccines in that it not only offers an easy to use, non-invasive, needle-free alternative to more conventional parenteral injection, but it also creates an opportunity to elicit both systemic and (crucially) mucosal immune responses which may increase the capability of controlling pathogens at the site of entry. Immune responses to “naked” antigens are often modest and it is widely accepted that incorporation of an adjuvant is a prerequisite for the achievement of clinically effective nasal vaccines. Many existing adjuvants are sub-optimal or unsuitable because of local toxicity or poor enhancement of immunogenicity. Chitosan, particularly chitosan salts, have now been used in several preclinical and clinical studies with good tolerability, excellent immune stimulation and positive clinical results across a number of infections. Particularly significant evidence supporting chitosan as an adjuvant for nasal vaccination comes from clinical investigations on a norovirus vaccine; this demonstrated the ability of chitosan (ChiSys®), when combined with monophosphoryl lipid, to evoke robust immunological responses and confer protective immunity following (enteral) norovirus challenge. This article summarizes the totality of the meaningful information (including key unpublished data) supporting the development of chitosan-adjuvanted vaccines. PMID:24346613

  7. Preparation and Characterization of Extruded Composites Based on Polypropylene and Chitosan Compatibilized with Polypropylene-Graft-Maleic Anhydride.

    PubMed

    Carrasco-Guigón, Fernando Javier; Rodríguez-Félix, Dora Evelia; Castillo-Ortega, María Mónica; Santacruz-Ortega, Hisila C; Burruel-Ibarra, Silvia E; Encinas-Encinas, Jose Carmelo; Plascencia-Jatomea, Maribel; Herrera-Franco, Pedro Jesus; Madera-Santana, Tomas Jesus

    2017-01-25

    The preparation of composites of synthetic and natural polymers represent an interesting option to combine properties; in this manner, polypropylene and chitosan extruded films using a different proportion of components and polypropylene-graft-maleic anhydride (PPgMA) as compatibilizer were prepared. The effect of the content of the biopolymer in the polypropylene (PP) matrix, the addition of compatibilizer, and the particle size on the properties of the composites was analyzed using characterization by fourier transform-infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), tensile strength, and contact angle, finding that in general, the addition of the compatibilizer and reducing the particle size of the chitosan, favored the physicochemical and morphological properties of the films.

  8. Preparation and Characterization of Extruded Composites Based on Polypropylene and Chitosan Compatibilized with Polypropylene-Graft-Maleic Anhydride

    PubMed Central

    Carrasco-Guigón, Fernando Javier; Rodríguez-Félix, Dora Evelia; Castillo-Ortega, María Mónica; Santacruz-Ortega, Hisila C.; Burruel-Ibarra, Silvia E.; Encinas-Encinas, Jose Carmelo; Plascencia-Jatomea, Maribel; Herrera-Franco, Pedro Jesus; Madera-Santana, Tomas Jesus

    2017-01-01

    The preparation of composites of synthetic and natural polymers represent an interesting option to combine properties; in this manner, polypropylene and chitosan extruded films using a different proportion of components and polypropylene-graft-maleic anhydride (PPgMA) as compatibilizer were prepared. The effect of the content of the biopolymer in the polypropylene (PP) matrix, the addition of compatibilizer, and the particle size on the properties of the composites was analyzed using characterization by fourier transform-infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), tensile strength, and contact angle, finding that in general, the addition of the compatibilizer and reducing the particle size of the chitosan, favored the physicochemical and morphological properties of the films. PMID:28772464

  9. Thermo-responsive chitosan-graft-poly(N-isopropylacrylamide) injectable hydrogel for cultivation of chondrocytes and meniscus cells.

    PubMed

    Chen, Jyh-Ping; Cheng, Tai-Hong

    2006-12-08

    A thermo-responsive comb-like polymer with chitosan as the backbone and pendant poly(N-isopropylacrylamide) (PNIPAM) groups has been synthesized by grafting PNIPAM-COOH with a single carboxy end group onto chitosan through amide bond linkages. The copolymer exhibits reversible temperature-responsive soluble-insoluble characteristics with the lower critical solution temperature (LCST) being at around 30 degrees C. Results from SEM observations confirm a porous 3D hydrogel structure with interconnected pores ranging from 10 to 40 microm at physiological temperature. A preliminary in vitro cell culture study has demonstrated the usefulness of this hydrogel as an injectable cell-carrier material for entrapping chondrocytes and meniscus cells. The hydrogel not only preserves the viability and phenotypic morphology of the entrapped cells but also stimulates the initial cell-cell interactions.

  10. Surface Molecularly Imprinted Polymer of Chitosan Grafted Poly(methyl methacrylate) for 5-Fluorouracil and Controlled Release

    PubMed Central

    Zheng, Xue-Fang; Lian, Qi; Yang, Hua; Wang, Xiuping

    2016-01-01

    The molecular surface imprinted graft copolymer of chitosan with methyl methacrylate (MIP-CS-g-PMMA) were prepared by free radical polymerization with 5-fluorouracil (5-FU) as the template molecule using initiator of ammonium persulfate as adsorption system. MIPs were characterized by FTIR, X-ray diffraction, thermo-gravimetric analysis, 1H NMR and SEM. The mechanism of graft copolymerization and factors affected graft reaction were studied in details, and the optimum reaction conditions (to the highest %G and %E as the standard) were obtained at [MMA] 1.2 mol/L, [Chitosan] 16.67 mol/L, [initiator] 0.0062 mol/L, temperature 60 °C and reaction time 7 h. MIPs exhibited high recognition selectivity and excellent combining affinity to template molecular. The in vitro release of the 5-FU was highly pH-dependent and time delayed. The release behavior showed that the drugs did not release in simulated gastric fluid (pH = 1.0), and the drug release was small in the simulated small intestinal fluid (pH = 6.8), and drug abrupt release will be produced in the simulated colon fluid (pH = 7.4), indicating excellent colon-specific drug delivery behavior. PMID:26892676

  11. Surface Molecularly Imprinted Polymer of Chitosan Grafted Poly(methyl methacrylate) for 5-Fluorouracil and Controlled Release.

    PubMed

    Zheng, Xue-Fang; Lian, Qi; Yang, Hua; Wang, Xiuping

    2016-02-19

    The molecular surface imprinted graft copolymer of chitosan with methyl methacrylate (MIP-CS-g-PMMA) were prepared by free radical polymerization with 5-fluorouracil (5-FU) as the template molecule using initiator of ammonium persulfate as adsorption system. MIPs were characterized by FTIR, X-ray diffraction, thermo-gravimetric analysis, (1)H NMR and SEM. The mechanism of graft copolymerization and factors affected graft reaction were studied in details, and the optimum reaction conditions (to the highest %G and %E as the standard) were obtained at [MMA] 1.2 mol/L, [Chitosan] 16.67 mol/L, [initiator] 0.0062 mol/L, temperature 60 °C and reaction time 7 h. MIPs exhibited high recognition selectivity and excellent combining affinity to template molecular. The in vitro release of the 5-FU was highly pH-dependent and time delayed. The release behavior showed that the drugs did not release in simulated gastric fluid (pH = 1.0), and the drug release was small in the simulated small intestinal fluid (pH = 6.8), and drug abrupt release will be produced in the simulated colon fluid (pH = 7.4), indicating excellent colon-specific drug delivery behavior.

  12. Enhanced and selective adsorption of mercury ions on chitosan beads grafted with polyacrylamide via surface-initiated atom transfer radical polymerization.

    PubMed

    Li, Nan; Bai, Renbi; Liu, Changkun

    2005-12-06

    Enhanced and selective removal of mercury ions was achieved with chitosan beads grafted with polyacrylamide (chitosan-g-polyacrylamide) via surface-initiated atom transfer radical polymerization (ATRP). The chitosan-g-polyacrylamide beads were found to have significantly greater adsorption capacities and faster adsorption kinetics for mercury ions than the chitosan beads. At pH 4 and with initial mercury concentrations of 10-200 mg/L, the chitosan-g-polyacrylamide beads can achieve a maximum adsorption capacity of up to 322.6 mg/g (in comparison with 181.8 mg/g for the chitosan beads) and displayed a short adsorption equilibrium time of less than 60 min (compared to more than 15 h for the chitosan beads). Coadsorption experiments with both mercury and lead ions showed that the chitosan-g-polyacrylamide beads had excellent selectivity in the adsorption of mercury ions over lead ions at pH < 6, in contrast to the chitosan beads, which did not show clear selectivity for either of the two metal species. Mechanism study suggested that the enhanced mercury adsorption was due to the many amide groups grafted onto the surfaces of the beads, and the selectivity in mercury adsorption can be attributed to the ability of mercury ions to form covalent bonds with the amide. It was found that adsorbed mercury ions on the chitosan-g-polyacrylamide beads can be effectively desorbed in a perchloric acid solution, and the regenerated beads can be reused almost without any loss of adsorption capacity.

  13. Detection of trace amounts of Pb(II) by schiff base-chitosan-grafted multiwalled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Moghimi, Ali

    2013-07-01

    A simple, highly sensitive, accurate and selective method for determination of trace amounts of Pb(II) in water samples is presented. A novel Schiff base-chitosan-grafted multiwalled carbon nanotubes (S-CS-MWCNTs) solid-phase extraction adsorbent was synthesized by covalently grafting a Schiff base-chitosan (S-CS) onto the surfaces of oxidized MWCNTs. The stability of a chemically (S-CS-MWCNTs) especially in concentrated hydrochloric acid which was then used as a recycling and preconcentration reagent for further uses of (S-CS-MWCNTs). The method is based on selective chelation of Pb(II) on surfactant coated C18, modified with a Schiff base-chitosan-grafted multiwalled carbon nanotubes (S-CS-MWCNTs). The retained ions were then eluted with 4 mL of 4 M nitric acid and determined by flame atomic absorption spectrometry (FAAS) at 283.3 nm for Pb. The influence of flow rates of sample and eluent solutions, pH, break-through volume, effect of foreign ions on chelation and recovery were investigated. 1.5 g of surfactant coated C18 adsorbs 40 mg of the Schiff s base which in turn can retain 15.0 ± 0.9 mg of each of the two ions. The limit of detection (3σ) for Pb(II) was found to be 3.20 ng L-1. The enrichment factor for both ions are 100. The mentioned method was successfully applied on determination of lead in different water samples. The ions were also speciated by means of three columns system.

  14. Protein adsorption, fibroblast activity and antibacterial properties of poly(3-hydroxybutyric acid-co-3-hydroxyvaleric acid) grafted with chitosan and chitooligosaccharide after immobilized with hyaluronic acid.

    PubMed

    Hu, S-G; Jou, C-H; Yang, M C

    2003-07-01

    Poly(3-hydroxybutyric acid-co-3-hydroxyvaleric acid) (PHBV) membrane was treated with ozone and grafted with acrylic acid. The resulting membranes were further grafted with chitosan (CS) or chitooligosaccharide (COS) via esterification. Afterward hyaluronic acid (HA) was immobilized onto CS- or COS-grafting membranes. The antibacterial activity of CS and COS against Staphylococus aureus, Escherichia coli, and Pseudomonas aeruginosa was preserved after HA immobilization. Among them, CS-grafted PHBV membrane showed higher antibacterial activity than COS-grafted PHBV membrane. In addition, after CS- or COS-grafting, the L929 fibroblasts attachment and protein adsorption were improved, while the cell number was decrease. After immobilizing HA, the cell proliferation was promoted, the protein adsorption was decreased, and the cell attachment was slightly lower than CS- or COS-grafting PHBV.

  15. Removal of reactive dyes from textile wastewater by immobilized chitosan upon grafted Jute fibers with acrylic acid by gamma irradiation

    NASA Astrophysics Data System (ADS)

    Hassan, Mahmoud S.

    2015-10-01

    Jute fibers were grafted with acrylic acid by gamma irradiation technique. Chitosan was immobilized upon the grafted Jute fibers to be used as an adsorbent for waste reactive dye. The treated Jute fibers were characterized by using of Fourier-transform infrared spectroscopy (FTIR), Scanning electron microscopy (SEM) and X-ray diffraction (XRD). The effect of Jute treatment on its thermal stability by using thermogravimetric analysis (TGA) and its mechanical properties were investigated. The adsorption isotherm and the different factors affecting the dye adsorption such as pH and contact time were also studied. It was found that the dye adsorption was enhanced in the low pH range and increased with increasing of the contact time, regardless of temperature change.

  16. Synthesis of poly(sulfobetaine methacrylate)-grafted chitosan under γ-ray irradiation for alamethicin assembly.

    PubMed

    Zhou, Yuan; Dong, Ping; Wei, Yanqi; Qian, Jun; Hua, Daoben

    2015-08-01

    Interaction between peptide and lipid membrane plays a major role in biological activity of membrane-active peptide. We describe here a new biocompatible polymeric assembly to support membrane peptide. Specifically, chitosan-graft-poly(sulfobetaine methacrylate) (CS-g-PSBMA) was synthesized for alamethicin assembly by controlled polymerization under γ-ray irradiation. The graft copolymer could self-assemble into micelles in distilled water for supporting alamethicin. The assembly of alamethicin with CS-g-PSBMA micelles in aqueous solutions was related with the ratio of alamethicin/CS-g-PSBMA: the more alamethicin, the smaller sizes of the hybrid complex. Moreover, alamethicin penetrated into the hydrophobic cores of CS-g-PSBMA micelles while displayed secondary helical conformation in the complex. The results indicate that CS-g-PSBMA assemblies can be used to support membrane peptide.

  17. Bioactive and metal uptake studies of carboxymethyl chitosan-graft-D-glucuronic acid membranes for tissue engineering and environmental applications.

    PubMed

    Jayakumar, R; Rajkumar, M; Freitas, H; Sudheesh Kumar, P T; Nair, S V; Furuike, T; Tamura, H

    2009-08-01

    Carboxymethyl chitosan-graft-D-glucuronic acid (CMCS-g-D-GA) was prepared by grafting D-GA onto CMCS in the presence of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC) and then the membranes were made from it. In this work, the bioactivity studies of CMCS-g-D-GA membranes were carried out and then characterized by SEM, CLSM, XRD and FT-IR. The CMCS-g-D-GA membranes were found to be bioactive. The adsorption of Ni2+, Zn2+ and Cu2+ ions onto CMCS-g-D-GA membranes has also been investigated. The maximum adsorption capacity of CMCS-g-D-GA for Ni2+, Zn2+ and Cu2+ was found to be 57, 56.4 and 70.2 mg/g, respectively. Hence, these membranes were useful for tissue engineering, environmental and water purification applications.

  18. Poly(methyl methacrylate)-grafted chitosan microspheres for controlled release of ampicillin.

    PubMed

    Changerath, Radhakumary; Nair, Prabha D; Mathew, Suresh; Nair, C P Reghunadhan

    2009-04-01

    Microspheres of 50-500 microm diameter were prepared from a blend of chitosan and chitosan-g-PMMA. Environmental scanning electron microscopic and SEM studies revealed that the microspheres are porous and the pores extend toward the inner core of the microspheres. The microspheres were also found to be hemocompatible and cytocompatible. A model drug ampicillin was used to evaluate the drug loading capacity and the controlled release properties of the microspheres. The system maintained a sustained release of ampicillin for a period of more than 8 days. The drug-loaded chitosan/chitosan-g-PMMA microspheres exhibited higher antibacterial activity for both the gram positive (ATCC 25923 S. aureus) and gram negative (ATCC 25922 E. coli) bacteria than the drug-loaded virgin chitosan microspheres. The percentage release and bioactivity of ampicillin was found to be higher for the chitosan/chitosan-g-PMMA microspheres than the virgin chitosan microspheres. Potential applications such as oral drug delivery, wound dressings, tissue engineering, and so forth, are envisaged from these microspheres.

  19. Low molecular weight polyethylenimine grafted N-maleated chitosan for gene delivery: properties and in vitro transfection studies.

    PubMed

    Lu, Bo; Xu, Xiao-Ding; Zhang, Xian-Zheng; Cheng, Si-Xue; Zhuo, Ren-Xi

    2008-10-01

    To develop chitosan-based efficient gene vectors, chitosans with different molecular weights were chemically modified with low molecular weight polyethylenimine. The molecular weight and composition of polyethylenimine grafted N-maleated chitosan (NMC-g-PEI) copolymers were characterized using gel permeation chromatography (GPC) and (1)H NMR, respectively. Agarose gel electrophoresis assay showed that NMC-g-PEI had good binding ability with DNA, and the particle size of the NMC-g-PEI/DNA complexes was 200-400 nm, as determined by a Zeta sizer. The nanosized complexes observed by scanning electron microscopy (SEM) exhibited a compact and spherical morphology. The NMC-g-PEI copolymers showed low cytotoxicity and good transfection activity, comparable to PEI (25 KDa) in both 293T and HeLa cell lines, except for NMC 50K-g-PEI. The results indicated that the molecular weight of NMC-g-PEI has an important effect on cytotoxicity and transfection activity, and low molecular weight NMC-g-PEI has a good potential as efficient nonviral gene vectors.

  20. Schiff base - Chitosan grafted L-monoguluronic acid as a novel solid-phase adsorbent for removal of congo red.

    PubMed

    Yuan, Bo; Qiu, Li-Gan; Su, Hong-Zhen; Cao, Cheng-Liang; Jiang, Ji-Hong

    2016-01-01

    A novel modified chitosan adsorbent (GL-SBCS) was synthesized by covalently grafting a Schiff base-chitosan (SBCS) onto the surface of l-monoguluronic acid. Physico-chemical investigation on the adsorption of congo red, an anionic azo dye by GL-SBCS has been carried out. The effect of different weight contents of chitosan in GL-SBCS composite, adsorbent dosage, initial pH and contract time were studied in detail using batch adsorption. Results showed that GL-SBCS exhibited better than normal CS and l-monoguluronic acid. Further investigation demonstrated that the adsorption pattern fitted well with the Langmuir model (R(2)>0.99) but less-satisfied the Freundlich model. Both ionic interaction as well as physical forces is responsible for binding of congo red with GL-SBCS as determined by zeta potential measurement Both sodium chloride and sodium dodecyl sulfate significantly influenced the adsorption process. SBCS would be a good method and resource to increase absorption efficiency for the removal of anionic dyes in a wastewater treatment process.

  1. Ligand-functionalized degradable polyplexes formed by cationic poly(aspartic acid)-grafted chitosan-cyclodextrin conjugates.

    PubMed

    Song, Hai-Qing; Li, Rui-Quan; Duan, Shun; Yu, Bingran; Zhao, Hong; Chen, Da-Fu; Xu, Fu-Jian

    2015-03-19

    Polypeptide-based degradable polyplexes attracted considerable attention in drug delivery systems. Polysaccharides including cyclodextrin (CD), dextran, and chitosan (CS) were readily grafted with cationic poly(aspartic acid)s (PAsps). To further enhance the transfection performances of PAsp-based polyplexes, herein, different types of ligand (folic acid, FA)-functionalized degradable polyplexes were proposed based on the PAsp-grafted chitosan-cyclodextrin conjugate (CCPE), where multiple β-CDs were tied on a CS chain. The FA-functionalized CCPE (i.e., CCPE-FA) was obtained via a host-guest interaction between the CD units of CCPE and the adamantane (Ad) species of Ad-modified FA (Ad-FA). The resulting CCPE/pDNA, CCPE-FA/pDNA, and ternary CCPE-FA/CCPE/pDNA (prepared by layer-by-layer assembly) polyplexes were investigated in detail using different cell lines. The CCPE-based polyplexes displayed much higher transfection efficiencies than the CS-based polyplexes reported earlier by us. The ternary polyplexes of CCPE-FA/CCPE/pDNA produced excellent gene transfection abilities in the folate receptor (FR)-positive tumor cells. This work would provide a promising means to produce highly efficient polyplexes for future gene therapy applications.

  2. Ethyl chitosan synthesis and quantification of the effects acquired after grafting it on a cotton fabric, using ANOVA statistical analysis.

    PubMed

    Popescu, Vasilica; Muresan, Augustin; Popescu, Gabriel; Balan, Mihaela; Dobromir, Marius

    2016-03-15

    Three ethyl chitosans (ECSs) have been prepared using the ethyl chloride (AA) that was obtained in situ. Each ECS was applied on a 100% cotton fabric through a pad-dry-cure technology. Using the ANOVA as statistic method, the wrinkle-proofing effects have been determined varying the concentrations of AA (0.1-2.1mmol) and chitosan (CS) (0.1-2.1mmol). Alkylation and grafting mechanisms have been confirmed by the results of FTIR, (1)H NMR, XPS, SEM, DSC and termogravimetric analyses. The performances of each ECS as wrinkle-proofing agent have been revealed through quantitative methods (taking-up degree, wrinkle-recovering angle, tensile strength and effect's durability). The ECSs confer wrinkle-recovering angle and tensile strength higher than those of the witness sample. Durability of ECSs grafted on cotton have been demonstrated by a good capacity of dyeing with non-specific (acid/anionic and cationic) dyes under severe working conditions (100°C, 60min) and a good antimicrobial capacity.

  3. N-Succinyl-chitosan grafted with low molecular weight polyethylenimine as a serum-resistant gene vector.

    PubMed

    Lu, Bo; Sun, Yun-Xia; Li, Yun-Qiu; Zhang, Xian-Zheng; Zhuo, Ren-Xi

    2009-06-01

    Low transfection efficiency and inactivation by serum are the major drawbacks for cationic polymers when used as non-viral gene vectors. Here, a series of N-succinyl-chitosan-graft-polyethylenimine (NSC-g-PEI) copolymers with different compositions were synthesized through grafting low molecular weight PEI (800 Da) to N-succinyl-chitosan. An agarose gel electrophoresis assay showed NSC-g-PEIs had good binding capability with DNA and the particle size of the NSC-g-PEI-DNA complexes was between 150 to 300 nm as determined by a Zeta sizer. In vitro transfection of NSC-g-PEI-DNA complexes for 293T, HeLa and CHO cells was investigated. It was found that the transfection efficiency of NSC-g-PEI-DNA complexes was higher than that of DNA combined PEI (25 kDa) and the transfection efficiency increased with the increasing GD of PEI. More importantly, the NSC-g-PEI-DNA complexes were stable and the transfection efficiency was not affected obviously in the presence of serum with different concentrations. In addition, NSC-g-PEIs had a lower cytotoxicity than PEI (25 kDa) and the toxicity increased with increasing GD of PEI. The NSC-g-PEI copolymers will have a good potential as efficient non-viral gene vectors in the presence of serum.

  4. Preparation and characterization of poly(maleic acid)-grafted cross-linked chitosan microspheres for Cd(II) adsorption.

    PubMed

    Yu, Zhenzhen; Dang, Qifeng; Liu, Chengsheng; Cha, Dongsu; Zhang, Haifeng; Zhu, Wenjing; Zhang, Qianqian; Fan, Bing

    2017-09-15

    A novel adsorbent, composed of poly(maleic acid)-grafted cross-linked chitosan microspheres (PMACCMs), was prepared via cross-linking with glutaraldehyde and modification by grafting maleic acid. FTIR, zeta potential, elemental analysis, (13)C NMR, DTG, laser particle size analysis, SEM, and BET methods were applied to characterize PMACCMs, exhibiting a successful fabrication, good thermostability, and well-defined surface microstructure beneficial to Cd(II) adsorption. The effects of pH, contact time, and initial concentration on Cd(II) adsorption were also investigated, and the maximum adsorption capacity was 39.2mgg(-1), indicating a great improvement as compared with that (14.5mgg(-1)) of cross-linked chitosan microspheres. The experimental data were well fitted with pseudo-second-order kinetic and Langmuir isotherm models. Five-cycle reusability tests demonstrated PMACCMs could be repeatedly used with a small adsorption capacity loss (<15%). Additionally, the adsorption mechanism was proposed. All the results confirmed that PMACCMs, which presented outstanding adsorption capability and reusability, could be a good candidate for wastewater purification. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Synthesis and characterization of N-vinylcaprolactam/N,N-dimethylacrylamide grafted onto chitosan networks by gamma radiation

    NASA Astrophysics Data System (ADS)

    Pérez-Calixto, M. P.; Ortega, A.; Garcia-Uriostegui, L.; Burillo, G.

    2016-02-01

    N-vinylcaprolactam (NVCL) and N,N-dimethylacrylamide (DMAAm) were grafted onto crosslinked chitosan by gamma radiation, using direct and indirect (pre-irradiation oxidative) methods. The binary graft systems were synthesized in one and two steps to evaluate the influences of architecture on the properties of the polymeric material. Maximum grafting percentages were obtained by the direct method. The different systems obtained were characterized by FTIR and TGA. The equilibrium swelling time of the (net-CS)-g-NVCL/DMAAm and [(net-CS)-g-NVCL]-g-DMAAm systems was 75 and 25 min, respectively, while crosslinked CS required about 24 h. Thermal and pH sensitivity were conserved in all systems; the pH response in [(net-CS)-g-NVCL]-g-DMAAm (LCST: 37°, pH: 5.2) is more defined than (net-CS)-g-NVCL/DMAAm (LCST: 37 °C, pH: 3.8). Grafting radiation showed to be an effective technique to modify CS hydrogels.

  6. Durable antistatic coating for polymethylmethacrylate

    NASA Technical Reports Server (NTRS)

    Hadek, V.; Somoano, R. B.; Rembaum, A. (Inventor)

    1977-01-01

    A durable antistatic coating is achieved on polymethylmethacrylate plastic without affecting its optical clarity by applying to the surface of the plastic a low molecular weight solvent having a high electron affinity and a high dipole moment, such as acentonitrile or nitromethane alone or in the presence of photopolymerizable monomer. The treated polymethylmethacrylate plastic dissipates most of the induced electrostatic charge and retains its optical clarity. The antistatic behavior persists after washing, rubbing and vacuum treatment.

  7. Acidic pH resistance of grafted chitosan on dental implant.

    PubMed

    Campos, Doris M; Toury, Bérengère; D'Almeida, Mélanie; Attik, Ghania N; Ferrand, Alice; Renoud, Pauline; Grosgogeat, Brigitte

    2015-05-01

    Over the last decade, access to dental care has increasingly become a service requested by the population, especially in the case of dental implants. However, the major cause of implant failure is an inflammatory disease: peri-implantitis. Currently, the adhesion strength of antibacterial coatings at implant surfaces remains a problem to solve. In order to propose a functionalized implant with a resistant antibacterial coating, a novel method of chitosan immobilization at implant surface has been investigated. Functionalization of the pre-active titanium (Ti) surface was performed using triethoxysilylpropyl succinic anhydride (TESPSA) as a coupling agent which forms a stable double peptide bond with chitosan. The chitosan presence and the chemical resistibility of the coating under acid pH solutions (pH 5 and pH 3) were confirmed by FTIR-ATR and XPS analyses. Furthermore, peel test results showed high adhesive resistance of the TESPSA/chitosan coating at the substrate. Cytocompatibility was evaluated by cell morphology with confocal imaging. Images showed healthy morphology of human gingival fibroblasts (HGF-1). Finally, the reported method for chitosan immobilization on Ti surface via peptide bindings allows for the improvement of its adhesive capacities and resistibility while maintaining its cytocompatibility. Surface functionalization using the TESPSA/chitosan coupling method is noncytotoxic and stable even in drastic environments as found in oral cavity, thus making it a valuable candidate for clinical implantology applications.

  8. Superabsorbent hydrogels via graft polymerization of acrylic acid from chitosan-cellulose hybrid and their potential in controlled release of soil nutrients.

    PubMed

    Essawy, Hisham A; Ghazy, Mohamed B M; El-Hai, Farag Abd; Mohamed, Magdy F

    2016-08-01

    Superabsorbent polymers fabricated via grafting polymerization of acrylic acid from chitosan (CTS) yields materials that suffer from poor mechanical strength. Hybridization of chitosan with cellulose (Cell) via chemical bonding using thiourea formaldehyde resin increases the flexibility of the produced hybrid (CTS/Cell). The hybridization process and post graft polymerization of acrylic acid was followed using Fourier transform infrared (FTIR). Also, the obtained structures were homogeneous and exhibited uniform surface as could be shown from imaging with scanning electron microscopy (SEM). Thus, the polymers derived from the grafting of polyacrylic acid from (CTS/Cell) gave rise to much more mechanically robust structures ((CTS/Cell)-g-PAA) that bear wide range of pH response due to presence of chitosan and polyacrylic acid in one homogeneous entity. Additionally, the obtained structures possessed greater water absorbency 390, 39.5g/g in distilled water and saline (0.9wt.% NaCl solution), respectively, and enhanced retention potential even at elevated temperatures as revealed by thermogravimetric analysis (TGA). This could be explained by the high grafting efficiency (GE%), 86.4%, and grafting yield (GY%), 750%. The new superabsorbent polymers proved to be very efficient devices for controlled release of fertilizers into the soil which expands their use in agriculture and horticultural applications. Copyright © 2016 Elsevier B.V. All rights reserved.

  9. Synthesis and evaluation of chitosan-graft-poly (2-hydroxyethyl methacrylate-co-itaconic acid) as a drug carrier for controlled release of tramadol hydrochloride.

    PubMed

    Subramanian, Kaliappa Gounder; Vijayakumar, Vediappan

    2012-07-01

    Chitosan-graft-poly (2-hydroxyethyl methacrylate-co-itaconic acid) has been synthesized for different feed ratios of 2-hydroxyethyl methacrylate and itaconic acid and characterized by FT-IR, thermogravimetry and swelling in simulated biological fluids (SBF) and evaluated as a drug carrier with model drug, tramadol hydrochloride (TRM). Grafting decreased the thermal stability of chitosan. FT-IR spectra of tablet did not reveal any molecular level (i.e. at <10 nm scale) drug-polymer interaction. But differential scanning calorimetric studies indicated a probable drug-polymer interaction at a scale >100 nm level. The observed Korsmeyer-Peppas's power law exponents (0.19-1.21) for the in vitro release profiles of TRM in SBF and other drugs such as 5-fluorouracil (FU), paracetamol (PCM) and vanlafaxine hydrochloride (VNF) with the copolymer carriers revealed an anomalous drug release mechanism. The decreased release rates for the grafted chitosan and the enhanced release rate for the grafts with increasing itaconic acid content in the feed were more likely attributed to the enhanced drug-matrix interaction and polymer-SBF interactions, respectively. The different release profiles of FU, PCM, TRM and VNF with the copolymer matrix are attributed to the different chemical structures of drugs. The above features suggest the graft copolymer's candidature for use as a promising oral drug delivery system.

  10. Hexanoic acid and polyethylene glycol double grafted amphiphilic chitosan for enhanced gene delivery: influence of hydrophobic and hydrophilic substitution degree.

    PubMed

    Layek, Buddhadev; Haldar, Manas K; Sharma, Gitanjali; Lipp, Lindsey; Mallik, Sanku; Singh, Jagdish

    2014-03-03

    Gene therapy holds immense potential as a future therapeutic strategy for the treatment of numerous genetic diseases which are incurable to date. Nevertheless, safe and efficient gene delivery remains the most challenging aspects of gene therapy. To overcome this difficulty a series of hexanoic acid (HA) and monomethoxy poly(ethylene glycol) (mPEG) double grafted chitosan-based (HPC) nanomicelles were developed as nonviral gene carrier. HPC polymers with various HA and mPEG substitution degrees were synthesized, and their chemical structures were confirmed by (1)H NMR spectroscopy. HPC nanomicelles exhibited excellent blood compatibility and cell viability, as demonstrated by in vitro hemolysis and MTT assay, respectively. The cationic HPC nanomicelles retained the plasmid DNA (pDNA) binding capacity of chitosan and formed stable HPC/pDNA polyplexes with diameters below 200 nm. Both hydrophobic and hydrophilic substitution resulted in suppressed nonspecific protein adsorption on HPC/pDNA polyplexes and increased pDNA dissociation. However, resistance against DNase I degradation was enhanced by HA conjugation while being inhibited by mPEG substitution. Amphiphilic modification resulted in 3-4.5-fold higher cellular uptake in human embryonic kidney 293 cells (HEK 293) mainly through clathrin-mediated pathway. The optimal HPC/pDNA polyplexes displayed 50-fold and 1.2-fold higher gene transfection compared to unmodified chitosan and Fugene, respectively, in HEK 293 cells. Moreover, both the cellular uptake and in vitro transfection study suggested a clear dependence of gene expression on the extent of HA and mPEG substitution. These findings demonstrate that amphiphilic HPC nanomicelles with the proper combination of HA and mPEG substitution could be used as a promising gene carrier for efficient gene therapy.

  11. Separation and extraction of Co(II) using magnetic chitosan nanoparticles grafted with β-cyclodextrin and determination by FAAS

    NASA Astrophysics Data System (ADS)

    Moghimi, Ali

    2014-12-01

    A novel and selective method for the fast determination of trace amounts of Co(II) ions in water samples has been developed. The procedure is based on the selective sorption of Co(II) ions using magnetic chitosan nanoparticles grafted with β-cyclodextrin at different pH followed by elution with organic eluents and determination by atomic absorption spectrometry The preconcentration factor was 100 (1 mL elution volume) for a 100 mL sample volume. The limit of detection of the proposed method is 1.0 ng mL-1. The maximum sorption capacity of sorbent under optimum conditions has been found to be 5 mg of Co per gram of sorbent. The relative standard deviation under optimum conditions was 3.0% ( n = 10). Accuracy and applicability of the method was estimated using test samples of natural and model water with different amounts of Co(II).

  12. Ligand-functionalized degradable polyplexes formed by cationic poly(aspartic acid)-grafted chitosan-cyclodextrin conjugates

    NASA Astrophysics Data System (ADS)

    Song, Hai-Qing; Li, Rui-Quan; Duan, Shun; Yu, Bingran; Zhao, Hong; Chen, Da-Fu; Xu, Fu-Jian

    2015-03-01

    Polypeptide-based degradable polyplexes attracted considerable attention in drug delivery systems. Polysaccharides including cyclodextrin (CD), dextran, and chitosan (CS) were readily grafted with cationic poly(aspartic acid)s (PAsps). To further enhance the transfection performances of PAsp-based polyplexes, herein, different types of ligand (folic acid, FA)-functionalized degradable polyplexes were proposed based on the PAsp-grafted chitosan-cyclodextrin conjugate (CCPE), where multiple β-CDs were tied on a CS chain. The FA-functionalized CCPE (i.e., CCPE-FA) was obtained via a host-guest interaction between the CD units of CCPE and the adamantane (Ad) species of Ad-modified FA (Ad-FA). The resulting CCPE/pDNA, CCPE-FA/pDNA, and ternary CCPE-FA/CCPE/pDNA (prepared by layer-by-layer assembly) polyplexes were investigated in detail using different cell lines. The CCPE-based polyplexes displayed much higher transfection efficiencies than the CS-based polyplexes reported earlier by us. The ternary polyplexes of CCPE-FA/CCPE/pDNA produced excellent gene transfection abilities in the folate receptor (FR)-positive tumor cells. This work would provide a promising means to produce highly efficient polyplexes for future gene therapy applications.Polypeptide-based degradable polyplexes attracted considerable attention in drug delivery systems. Polysaccharides including cyclodextrin (CD), dextran, and chitosan (CS) were readily grafted with cationic poly(aspartic acid)s (PAsps). To further enhance the transfection performances of PAsp-based polyplexes, herein, different types of ligand (folic acid, FA)-functionalized degradable polyplexes were proposed based on the PAsp-grafted chitosan-cyclodextrin conjugate (CCPE), where multiple β-CDs were tied on a CS chain. The FA-functionalized CCPE (i.e., CCPE-FA) was obtained via a host-guest interaction between the CD units of CCPE and the adamantane (Ad) species of Ad-modified FA (Ad-FA). The resulting CCPE/pDNA, CCPE

  13. Synthesis and characterisation of chitosan crosslinked-β-cyclodextrin grafted silylated magnetic nanoparticles for controlled release of Indomethacin

    NASA Astrophysics Data System (ADS)

    Anirudhan, T. S.; Dilu, D.; Sandeep, S.

    2013-10-01

    In this work, a novel hydrogel, chitosan crosslinked β-cyclodextrin grafted silylated magnetic nanoparticle (CTSCD-g-SilylMNP) was synthesised as a drug delivery system onto which Indomethacin (IND) drug was loaded. Characterisation of the drug delivery system was carried out by Tunnelling electron microscopy, Scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction analysis, Dynamic light scattering and a Vibrating sample magnetometer. Swelling behaviour, in vitro drug release kinetics, and encapsulation efficiency of CTSCD-g-SilylMNP were studied. Swelling behaviour varied according to pH. In vitro release studies revealed that CTSCD-g-SilylMNP demonstrated a swelling and diffusion controlled release. Dependence of pH was also studied. Encapsulation efficiency (EE) at different percentages of drug loadings was studied. The results collectively suggest that the hydrogel has promising application in the field of controlled drug release. The biodegradability also adds to the advantage.

  14. 21 CFR 888.3027 - Polymethylmethacrylate (PMMA) bone cement.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Polymethylmethacrylate (PMMA) bone cement. 888... Polymethylmethacrylate (PMMA) bone cement. (a) Identification. Polymethylmethacrylate (PMMA) bone cement is a device...: Polymethylmethacrylate (PMMA) Bone Cement.”...

  15. 21 CFR 888.3027 - Polymethylmethacrylate (PMMA) bone cement.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Polymethylmethacrylate (PMMA) bone cement. 888... Polymethylmethacrylate (PMMA) bone cement. (a) Identification. Polymethylmethacrylate (PMMA) bone cement is a device...: Polymethylmethacrylate (PMMA) Bone Cement.” ...

  16. 21 CFR 888.3027 - Polymethylmethacrylate (PMMA) bone cement.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Polymethylmethacrylate (PMMA) bone cement. 888... Polymethylmethacrylate (PMMA) bone cement. (a) Identification. Polymethylmethacrylate (PMMA) bone cement is a device...: Polymethylmethacrylate (PMMA) Bone Cement.” ...

  17. 21 CFR 888.3027 - Polymethylmethacrylate (PMMA) bone cement.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Polymethylmethacrylate (PMMA) bone cement. 888... Polymethylmethacrylate (PMMA) bone cement. (a) Identification. Polymethylmethacrylate (PMMA) bone cement is a device...: Polymethylmethacrylate (PMMA) Bone Cement.” ...

  18. 21 CFR 888.3027 - Polymethylmethacrylate (PMMA) bone cement.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Polymethylmethacrylate (PMMA) bone cement. 888... Polymethylmethacrylate (PMMA) bone cement. (a) Identification. Polymethylmethacrylate (PMMA) bone cement is a device...: Polymethylmethacrylate (PMMA) Bone Cement.” ...

  19. Synthesis, characterisation and preliminary investigation of the haemocompatibility of polyethyleneimine-grafted carboxymethyl chitosan for gene delivery.

    PubMed

    Liu, Xuan; Mo, Yunfei; Liu, Xiaoyu; Guo, Rui; Zhang, Yi; Xue, Wei; Zhang, Yuanming; Wang, Changyong; Ramakrishna, Seeram

    2016-05-01

    The development of safe and efficient gene carriers is the key to the clinical success of gene therapy. In the present study, carboxymethyl chitosan (CMCS) was prepared by chitosan (CS) alkalisation and carboxymethylation reactions. Then polyethyleneimine (PEI) was grafted to the backbone of CMCS by an amidation reaction. The CMCS-PEI copolymer showed strong complexation capability with DNA to form nanoparticles, and achieved lower cytotoxicity and higher transfection efficiency compared with PEI (25 kDa) towards 293T and 3T3 cells. Moreover, the haemocompatibility of the CMCS-PEI copolymer was investigated through the aggregation, morphology and lysis of human red blood cells (RBCs), along with the impact on the clotting function with activated partial thromboplastin time (APTT), prothrombin time (PT) and thromboelastographic (TEG) assays. The results demonstrated that the CMCS-PEI copolymer with a concentration lower than 0.05 mg/mL had little impact on the aggregation, morphology or lysis of RBCs, or on blood coagulation. Therefore, the copolymer may be a strong alternative candidate as an effective and safe non-viral vector.

  20. Preparation of triethylene-tetramine grafted magnetic chitosan for adsorption of Pb(II) ion from aqueous solutions.

    PubMed

    Kuang, Shao-Ping; Wang, Zhao-Zhan; Liu, Jie; Wu, Zhan-Chao

    2013-09-15

    In this paper, a novel triethylene-tetramine grafted magnetic chitosan was synthesized. The chemical structure and the percentage content of each element of chitosan and its derivatives were characterized by elemental analysis, infrared spectroscopy, solid state (13)C NMR, X-ray diffraction analysis and thermogravimetric analysis, respectively. Their surface topography was observed by the transmission electron microscope. The results of adsorption kinetics and adsorption thermodynamics showed the adsorption mechanism could be better described by the pseudo-second-order equation (R>0.999). The adsorption isotherm was well fitted by the Langmuir equation (R>0.999), and 0

  1. Preparation, property of the complex of carboxymethyl chitosan grafted copolymer with iodine and application of it in cervical antibacterial biomembrane.

    PubMed

    Chen, Yu; Yang, Yumin; Liao, Qingping; Yang, Wei; Ma, Wanfeng; Zhao, Jian; Zheng, Xionggao; Yang, Yang; Chen, Rui

    2016-10-01

    Cervical erosion is one of the common diseases of women. The loop electrosurgical excisional procedure (LEEP) has been used widely in the treatment of the cervical diseases. However, there are no effective wound dressings for the postoperative care to protect the wound area from further infection, leading to increased secretion and longer healing time. Iodine is a widely used inorganic antibacterial agent with many advantages. However, the carrier for stable iodine complex antibacterial agents is lack. In the present study, a novel iodine carrier, Carboxymethyl chitosan-g-(poly(sodium acrylate)-co-polyvinylpyrrolidone) (CMCTS-g-(PAANa-co-PVP), was prepared by graft copolymerization of sodium acrylate (AANa) and N-vinylpyrrolidone (NVP) to a carboxymethyl chitosan (CMCTS) skeleton. The obtained structure could combine prominent property of poly(sodium acrylate) (PAANa) anionic polyelectrolyte segment and good complex property of polyvinylpyrrolidone (PVP) segment to iodine. The bioactivity of CMCTS could also be kept. The properties of the complex, CMCTS-g-(PAANa-co-PVP)-I2, were studied. The in vitro experiment shows that it has broad-spectrum bactericidal effects to virus, fungus, gram-positive bacteria and gram-negative bacteria. A CMCTS-g-(PAANa-co-PVP)-I2 complex contained cervical antibacterial biomembrane (CABM) was prepared. The iodine release from the CABM is pH-dependent. The clinic trial results indicate that CABM has better treatment effectiveness than the conventional treatment in the postoperative care of the LEEP operation. Copyright © 2016 Elsevier B.V. All rights reserved.

  2. Fabrication of a tunable glucose biosensor based on zinc oxide/chitosan-graft-poly(vinyl alcohol) core-shell nanocomposite.

    PubMed

    Shukla, S K; Deshpande, Swapneel R; Shukla, Sudheesh K; Tiwari, Ashutosh

    2012-09-15

    A potentiometrically tuned-glucose biosensor was fabricated using core-shell nanocomposite based on zinc oxide encapsulated chitosan-graft-poly(vinyl alcohol) (ZnO/CHIT-g-PVAL). In a typical experiment, ZnO/CHIT-g-PVAL core-shell nanocomposite containing <20 nm ZnO nanoparticles was synthesized using wet-chemical method. The glucose responsive bio-electrode, i.e., glucose oxidase/ZnO/chitosan-graft-poly(vinyl alcohol) (GOD/ZnO/CHIT-g-PVAL/ITO) was obtained by immobilization of glucose oxidase (GOD) onto the electrode made of resulting ZnO core-shell nanocomposite coated on the indium-tin oxide (ITO) glass substrate. The ZnO/CHIT-g-PVAL/ITO and GOD/ZnO/CHIT-g-PVAL electrodes were characterized with Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM), whereas ZnO/CHIT-g-PVAL size of core-shell nanoparticles were measured using transmission electron microscopy (TEM). The electrostatic interaction between GOD and ZnO/CHIT-g-PVAL provided the resulting tuned enzyme electrode with a high degree of enzyme immobilization and excellent lifetime stability. The response studies were carried out as a function of glucose concentration with potentiometric measurement. The GOD/ZnO/CHIT-g-PVAL/ITO bioelectrode has showed a linear potential response to the glucose concentration ranging from 2 μM to 1.2mM. The glucose biosensor exhibited a fast surface-controlled redox biochemistry with a detection limit of 0.2 μM, a sensitivity of >0.04 V/μM and a response time of three sec. ZnO/CHIT-g-PVAL core-shell nanocomposite could be a promising nanomaterials for a range of enzymic biosensors. Copyright © 2012 Elsevier B.V. All rights reserved.

  3. Removal of toxic heavy metal lead (II) using chitosan oligosaccharide-graft-maleic anhydride/polyvinyl alcohol/silk fibroin composite.

    PubMed

    P, Ajitha; K, Vijayalakshmi; M, Saranya; T, Gomathi; K, Rani; P N, Sudha; Sukumaran, Anil

    2017-11-01

    The present work was aimed to investigate the efficiency of novel chitosan oligosaccharide-graft-maleic anhydride(COS-g-MAH)/Polyvinyl alcohol (PVA)/silk fibroin (SF) composite for removing the toxic heavy metal lead (II) ion from aqueous solution by batch adsorption studies. Initially the chitosan oligosaccharide-graft-maleic anhydride copolymer has been prepared by utilizing ceric ammonium nitrate as an initiator and the optimised graft copolymer was then used for synthesizing COS-g-MAH/PVA/SF composite. The prepared samples were analyzed through FTIR and XRD studies. The FTIR results indicate that the grafted chitosan oligosaccharide copolymer was mixed homogeneously with silk fibroin and polyvinyl alcohol through intermolecular hydrogen bonding. The XRD results elucidate the changes in the crystalline behaviour of the prepared COS-g-MAH/PVA/silk fibroin composite. Both FTIR and XRD results revealed a strong interaction among COS-g-MAH, PVA and silk fibroin components. To evaluate the adsorption potential of the synthesized composite, the parameters such as pH, adsorbent dosage, contact time and initial Pb(II)ion concentration was investigated. The adsorption isotherms of Pb(II) could be described very well by Langmuir model and the kinetic results revealed that pseudo second order kinetics shows a better fit. This work provides a practical and high-efficient method for water treatment at moderate concentration of toxic heavy metals. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. Novel polymer micelles prepared from chitosan grafted hydrophobic palmitoyl groups for drug delivery.

    PubMed

    Jiang, Gang-Biao; Quan, Daping; Liao, Kairong; Wang, Haihua

    2006-01-01

    Chitosan-based polymer micelles have a splendid outlook for drug delivery owing to the interesting properties, abundance, and low cost of chitosan. A new method of preparation of water-soluble N-palmitoyl chitosan (PLCS) which can form micelles in water is developed in this paper. The preparation of PLCS was carried out by swollen chitosan coupling with palmitic anhydride in dimethyl sulfoxide (DMSO). The degree of substitution (DS) of PLCS was in the range of 1.2-14.2%, and the critical aggregation concentration (CAC) of PLCS micelles was in the range of 2.0 x 10(-3) to 37.2 x 10(-3) mg/mL. The properties of PLCS micelles such as encapsulation capacity and controlled release ability of hydrophobic model drug ibuprofen (IBU) were evaluated. Experimental results indicated that the loading capacity (LC) of PLCS was approximately 10%. The drug release strongly depended on pH and temperature: low pH and high temperature accelerated drug release markedly. Moreover, the IR, 1H NMR, and TEM of PLCS, IBU-loaded PLCS, and a PLCS-IBU physical mixture have been measured to show that IBU is loaded by PLCS micelles.

  5. Antibacterial and synergic effects of gallic acid-grafted-chitosan with β-lactams against methicillin-resistant Staphylococcus aureus (MRSA).

    PubMed

    Lee, Dae-Sung; Eom, Sung-Hwan; Kim, Young-Mog; Kim, Hye Seon; Yim, Mi-Jin; Lee, Sang-Hoon; Kim, Do-Hyung; Je, Jae-Young

    2014-10-01

    Methicillin-resistant Staphylococcus aureus (MRSA) is spreading worldwide, emphasizing the need to search for new antibiotics. The anti-MRSA activities of gallic acid-grafted-chitosans (GA-g-chitosans) were investigated against 2 MRSA standards and 10 MRSA clinical isolates by determining the minimum inhibitory concentrations (MICs). GA-g-chitosan (I), which has the highest gallic acid content, exhibited the strongest anti-MRSA activities, with MICs of 32-64 μg/mL. A time-kill investigation revealed that GA-g-chitosan (I) exhibited a bactericidal effect at twice the MIC, also demonstrating good thermal and pH stability. Investigation of cell envelope integrity showed the release of intracellular components with an increasing absorbance value at 260 nm, indicating cell envelope damage caused by the GA-g-chitosan (I), which was further confirmed by transmission electron microscopy. When GA-g-chitosans were combined with β-lactams, including ampicillin and penicillin, synergistic effects were observed on the 2 standard MRSA strains and on the 10 clinical isolates, with fractional inhibitory indices ranging from 0.125 to 0.625. In the time-kill dynamic confirmation test, synergistic bactericidal effects were observed for the combinations of GA-g-chitosans with β-lactams, and over 4.0 log CFU/mL reductions were observed after 24 h when combination treatment was used. These results may prove GA-g-chitosans to be a potent agent when combined with ampicillin and penicillin for the elimination of MRSA.

  6. Preparation of Novel Poly(hydroxyethyl methacrylate-coglycidyl methacrylate)-Grafted Core-Shell Magnetic Chitosan Microspheres and Immobilization of Lactase

    PubMed Central

    Zhao, Wei; Yang, Rui-Jin; Qian, Ting-Ting; Hua, Xiao; Zhang, Wen-Bin; Katiyo, Wendy

    2013-01-01

    Poly(hydroxyethyl methacrylate-co-glycidyl methacrylate)-grafted magnetic chitosan microspheres (HG-MCM) were prepared using reversed-phase suspension polymerization method. The HG-MCM presented a core-shell structure and regular spherical shape with poly(hydroxyethyl methacrylate-co-glycidyl methacrylate) grafted onto the chitosan layer coating the Fe3O4 cores. The average diameter of the magnetic microspheres was 10.67 μm, within a narrow size distribution of 6.6–17.4 μm. The saturation magnetization and retentivity of the magnetic microspheres were 7.0033 emu/g and 0.6273 emu/g, respectively. The application of HG-MCM in immobilization of lactase showed that the immobilized enzyme presented higher storage, pH and thermal stability compared to the free enzyme. This indicates that HG-MCM have potential applications in bio-macromolecule immobilization. PMID:23743822

  7. Preparation of novel poly(hydroxyethyl methacrylate-co-glycidyl methacrylate)-grafted core-shell magnetic chitosan microspheres and immobilization of lactase.

    PubMed

    Zhao, Wei; Yang, Rui-Jin; Qian, Ting-Ting; Hua, Xiao; Zhang, Wen-Bin; Katiyo, Wendy

    2013-06-06

    Poly(hydroxyethyl methacrylate-co-glycidyl methacrylate)-grafted magnetic chitosan microspheres (HG-MCM) were prepared using reversed-phase suspension polymerization method. The HG-MCM presented a core-shell structure and regular spherical shape with poly(hydroxyethyl methacrylate-co-glycidyl methacrylate) grafted onto the chitosan layer coating the Fe3O4 cores. The average diameter of the magnetic microspheres was 10.67 μm, within a narrow size distribution of 6.6-17.4 μm. The saturation magnetization and retentivity of the magnetic microspheres were 7.0033 emu/g and 0.6273 emu/g, respectively. The application of HG-MCM in immobilization of lactase showed that the immobilized enzyme presented higher storage, pH and thermal stability compared to the free enzyme. This indicates that HG-MCM have potential applications in bio-macromolecule immobilization.

  8. Magnetic Resonance Imaging of Mouse Islet Grafts Labeled with Novel Chitosan-Coated Superparamagnetic Iron Oxide Nanoparticles

    PubMed Central

    Kuo, Chien-Hung; Chien, Yu-Wen; Kuo, Hsiao-Yunn; Chen, Fu-Rong; Chen, Ming H.; Yen, Tzu-Chen; Tsai, Zei-Tsan

    2013-01-01

    Object To better understand the fate of islet isografts and allografts, we utilized a magnetic resonance (MR) imaging technique to monitor mouse islets labeled with a novel MR contrast agent, chitosan-coated superparamagnetic iron oxide (CSPIO) nanoparticles. Materials and Methods After being incubated with and without CSPIO (10 µg/ml), C57BL/6 mouse islets were examined under transmission electron microscope (TEM) and their insulin secretion was measured. Cytotoxicity was examined in α (αTC1) and β (NIT-1 and βTC) cell lines as well as islets. C57BL/6 mice were used as donors and inbred C57BL/6 and Balb/c mice were used as recipients of islet transplantation. Three hundred islets were transplanted under the left kidney capsule of each mouse and then MR was performed in the recipients periodically. At the end of study, the islet graft was removed for histology and TEM studies. Results After incubation of mouse islets with CSPIO (10 µg/mL), TEM showed CSPIO in endocytotic vesicles of α- and β-cells at 8 h. Incubation with CSPIO did not affect insulin secretion from islets and death rates of αTC1, NIT-1 and βTC cell lines as well as islets. After syngeneic and allogeneic transplantation, grafts of CSPIO-labeled islets were visualized on MR scans as persistent hypointense areas. At 8 weeks after syngeneic transplantation and 31 days after allogeneic transplantation, histology of CSPIO-labeled islet grafts showed colocalized insulin and iron staining in the same areas but the size of allografts decreased with time. TEM with elementary iron mapping demonstrated CSPIO distributed in the cytoplasm of islet cells, which maintained intact ultrastructure. Conclusion Our results indicate that after syngeneic and allogeneic transplantation, islets labeled with CSPIO nanoparticles can be effectively and safely imaged by MR. PMID:23658638

  9. Anticancer effect of atorvastatin nanostructured polymeric micelles based on stearyl-grafted chitosan.

    PubMed

    Mekhail, George M; Kamel, Amany O; Awad, Gehanne A S; Mortada, Nahed D

    2012-11-01

    The purpose of this study was to develop a new therapeutic approach for atorvastatin (ATV) adopting nanostructured polymeric micelles for its controlled delivery to the cancer cells. Amphiphilic block copolymers of stearyl chitosan (SC) and sulfated stearyl chitosan (S-SC) that could self assemble to form polymeric micelles with different degree of substitution (DS) were synthesized and characterized. The synthesized chitosan derivatives were able to self assemble and form micelles encapsulating ATV with critical micellar concentrations ranging from 6.9 to 21μg/ml, drug-loading ranging from 40% to 84.1% and encapsulation efficiency ranging from 10.4% to 35%. ATV caused a significant decrease in particle size and zeta potential of both SC and S-SC micelles. Micelles encapsulating ATV exhibited a sustained release and more cytotoxic activity against MCF 7 and HCT 116 cell lines than ATV alone. The 50% cellular growth inhibition (IC50%) of the drug decreased from 10.4 to 3.7 in case of MCF 7 and from 9.4 to 3.4 in case of HCT 116 after its loading in micelles. These results indicate that SC ATV polymeric micelles can be considered as a promising system for site specific controlled delivery of ATV to tumor cells. Copyright © 2012 Elsevier B.V. All rights reserved.

  10. Hydrogels based on dual curable chitosan-graft-polyethylene glycol-graft-methacrylate: application to layer-by-layer cell encapsulation.

    PubMed

    Poon, Yin Fun; Cao, Ye; Liu, Yunxiao; Chan, Vincent; Chan-Park, Mary B

    2010-07-01

    Ultraviolet (UV) photo-cross-linkable hydrogels have been commonly used for three-dimensional (3D) encapsulation of cells. Previous UV cross-linkable hydrogels have employed one-shot hardening of mixtures of hydrogels and cells. Here we propose an alternative method of making hydrogel-encapsulated cell constructs through layer by layer (LBL) buildup of alternating layers of cells and hydrogel. The LBL method potentially permits better spatial control of different cell types and control of cell orientation. Each hydrogel layer must be hardened before deposition of the next layer of cells. A UV-curable gel precursor that can also be gelled at physiological temperature is desirable to avoid repeated UV exposure of cells after deposition of each successive hydrogel layer. We designed, synthesized, and applied such a precursor, dual-curable-both thermoresponsive and UV-curable-chitosan-graft-polyethylene glycol-graft-methacrylate (CEGx-MA) copolymer (x is the PEG molecular weight in Daltons). We found that CEG350-MA copolymer solutions (5 wt % polymer) formed physical gels at approximately 37 degrees C and could be further photopolymerized to form thermally stable dual-cured hydrogels. This material was applied to the creation of a two-layer LBL smooth muscle cell (SMC)/hydrogel construct using temperature elevation to approximately 37 degrees C to gel each hydrogel layer. The physically gelled two-layered hydrogel/cell construct was finally exposed to a single UV shot to improve its mechanical properties and render it thermally stable. CEG350-MA solution and gel are nontoxic to SMCs. Cells remained mostly viable when they were encapsulated inside both physically gelled and dual-cured CEG350-MA and suffered little damage from the single brief UV exposure. The combination of LBL tissue engineering with a dual curable hydrogel precursor such as CEG350-MA permits the buildup of viable thick and complex tissues in a stable, biocompatible, and biodegradable matrix.

  11. Genotoxicity effect, antioxidant and biomechanical correlation: experimental study of agarose-chitosan bone graft substitute in New Zealand white rabbit model.

    PubMed

    Jebahi, Samira; Ben Saleh, Ghada; Saoudi, Mongi; Besaleh, Salma; Oudadesse, Hassane; Mhadbi, Moufida; Rebai, Tarek; Keskes, Hassib; El Feki, Abdelfattah

    2014-08-01

    Bone loss associated with skeletal trauma or metabolic diseases often requires bone grafting. In such situations, a biomaterial is necessary for migrated cells to produce new tissue. In this study, agarose-chitosan was implanted in the femoral condyle of New Zealand White rabbits that were divided into three groups: Group I was used as control; Groups II and III were used as implanted tissue with agarose-chitosan and presenting empty defects, respectively. This study evaluated the agarose-chitosan biocompatibility by determining the in vivo genotoxicity, oxidative stress balance that correlated with the hardness mechanical property. Moreover, the histopathological and quantitative elements analyzed by using inductively coupled plasma optical emission spectrometry were determined. After 30 days of implantation, the in vivo analysis of genotoxicity showed that agarose-chitosan did not induce chromosome aberration or micronucleus damage. A significant decrease in thiobarbituric and acid-reactive substance was observed after agarose-chitosan implantation in the bone tissue. Superoxide dismutase, catalase and glutathione peroxidase were significantly enhanced in agarose-chitosan-treated group compared with that of control group. A negative correlation coefficient of the mechanical property with malonyldialdehyde level was detected (R = -0.998). The histological study exhibited a significantly increased angiogenesis and newly formed tissue. No presence of inflammatory process, necrotic or fibrous tissue was detected. Major and trace elements such as Ca, P, Zn, Mg and Fe were increased significantly in the newly formed bone. These findings show that agarose-chitosan biomaterial implantation might be effective for treating trauma and bone regeneration.

  12. Synthesis and characterization of graft copolymers of chitosan with NIPAM and binary monomers for removal of Cr(VI), Cu(II) and Fe(II) metal ions from aqueous solutions.

    PubMed

    Lalita; Singh, Anirudh P; Sharma, Rajeev Kr

    2017-06-01

    To develop pH responsive hydrogels, N-isopropylacrylamide (NIPAM) has been grafted on to chitosan by free radical initiation method using azoisobutrylnitrile (AIBN) as an initiator. The optimum grafting conditions were worked out for grafting of NIPAM onto 1g of chitosan by varying one reaction parameter at a time and keeping all other parameters constant. Binary monomers were grafted for five different concentrations of comonomers acrylic acid (AAc), acrylamide (AAm) and acrylonitrile (AN) at optimum grafting conditions evaluated for GMA alone onto chitosan. The grafted copolymers were analyzed by FTIR, TGA/DTA, XRD and SEM. The swelling studies for the grafted samples were performed at various pH in order to explore their end use in sorption of Cr(VI), Fe(II) and Cu(II) ions from water system. Metal ion sorption behaviour of polymeric samples was studied as function of time, temperature and pH. Various metal ion sorption parameters such as percent uptake (Pu), partition coefficient (Kd) and retention capacity (Qr) were discussed. Chitosan grafted with binary monomers NIPAM-co-AAc and NIPAM-co-AAm showed best results for sorption of all three metal ions. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. Scleroderma en coup de sabre treated with polymethylmethacrylate - Case report*

    PubMed Central

    Franco, Joanna Pimenta de Araujo; Serra, Márcio Soares; Lima, Ricardo Barbosa; D’Acri, Antônio Macedo; Martins, Carlos José

    2016-01-01

    The scleroderma en coup de sabre is a variant of localized scleroderma that occurs preferentially in children. The disease progresses with a proliferative and inflammatory phase and later atrophy and residual deformity, which are treated with surgical techniques such as injectable fillers, transplanted or autologous fat grafting and resection of the lesion. Among the most widely used fillers is hyaluronic acid. However, there are limitations that motivate the search for alternatives, such as polymethylmethacrylate, a permanent filler that is biocompatible, non-toxic, non-mutagenic and immunologically inert. In order to illustrate its application, a case of scleroderma en coup de sabre in a 17-year-old patient, who was treated with polymethylmethacrylate with excellent aesthetic results, is reported. PMID:27192521

  14. Fibrous polymer grafted magnetic chitosan beads with strong poly(cation-exchange) groups for single step purification of lysozyme.

    PubMed

    Bayramoglu, Gulay; Tekinay, Turgay; Ozalp, V Cengiz; Arica, M Yakup

    2015-05-15

    Lysozyme is an important polypetide used in medical and food applications. We report a novel magnetic strong cation exchange beads for efficient purification of lysozyme from chicken egg white. Magnetic chitosan (MCHT) beads were synthesized via phase inversion method, and then grafted with poly(glycidyl methacrylate) (p(GMA)) via the surface-initiated atom transfer radical polymerization (SI-ATRP). Epoxy groups of the grafted polymer, were modified into strong cation-exchange groups (i.e., sulfonate groups) in the presence of sodium sulfite. The MCTH and MCTH-g-p(GMA)-SO3H beads were characterized by ATR-FTIR, SEM, and VSM. The sulphonate groups content of the modified MCTH-g-p(GMA)-4 beads was found to be 0.53mmolg(-1) of beads by the potentiometric titration method. The MCTH-g-p(GMA)-SO3H beads were first used as an ion-exchange support for adsorption of lysozyme from aqueous solution. The influence of different experimental parameters such as pH, contact time, and temperature on the adsorption process was evaluated. The maximum adsorption capacity was found to be 208.7mgg(-1) beads. Adsorption of lysozyme on the MCTH-g-p(GMA)-SO3H beads fitted to Langmuir isotherm model and followed the pseudo second-order kinetic. More than 93% of the adsorbed lysozyme was desorbed using Na2CO3 solution (pH 11.0). The purity of the lysozyme was checked by HPLC and SDS gel electrophoresis. In addition, the MCTH-g-p(GMA)-SO3H beads prepared in this work showed promising potential for separation of various anionic molecules.

  15. Preparation of chitosan-graft-(β-cyclodextrin) based sol-gel stationary phase for open-tubular capillary electrochromatography.

    PubMed

    Lü, Haixia; Li, Qingyin; Yu, Xiaowei; Yi, Jiaojiao; Xie, Zenghong

    2013-07-01

    A novel open-tubular CEC column coated with chitosan-graft-(β-CD) (CDCS) was prepared using sol-gel technique. In the sol-gel approach, owing to the 3D network of sol-gel and the strong chemical bond between the stationary phase and the surface of capillary columns, good chromatographic characteristics and unique selectivity in separating isomers were shown. The column efficiencies of 55,000∼163,000 plates/m for the isomeric xanthopterin and phenoxy acid herbicides using the sol-gel-derived CDCS columns were achieved. Good stabilities were demonstrated that the RSD values for the retention time of thiourea and isoxanthopterin were 1.3 and 1.4% (run to run, n = 5), 1.6 and 2.0% (day to day, n = 3), 2.9 and 3.1% (column to column, n = 3), respectively. The sol-gel-coated CDCS columns have shown improved separations of isomeric xanthopterin in comparison with CDCS-bonded capillary column. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Antibacterial and conductive injectable hydrogels based on quaternized chitosan-graft-polyaniline/oxidized dextran for tissue engineering.

    PubMed

    Zhao, Xin; Li, Peng; Guo, Baolin; Ma, Peter X

    2015-10-01

    Biomaterials with injectability, conductivity and antibacterial effect simultaneously have been rarely reported. Herein, we developed a new series of in situ forming antibacterial conductive degradable hydrogels using quaternized chitosan (QCS) grafted polyaniline with oxidized dextran as crosslinker. The chemical structures, morphologies, electrochemical property, conductivity, swelling ratio, rheological property, in vitro biodegradation and gelation time of hydrogels were characterized. Injectability was verified by in vivo subcutaneous injection on a Sprague Dawley rat. The antibacterial activity of the hydrogels was firstly evaluated employing antibacterial assay using Escherichia coli and Staphylococcus aureus in vitro. The hydrogels containing polyaniline showed enhanced antibacterial activity compared to QCS hydrogel, especially for hydrogels with 3 wt% polyaniline showing 95 kill% and 90kill% for E. coli and S. aureus, respectively. Compared with QCS hydrogel, the hydrogels with 3 wt% polyaniline still showed enhanced antibacterial activity for E. coli in vivo. The adipose-derived mesenchymal stem cells (ADMSCs) were used to evaluate the cytotoxicity of the hydrogels and hydrogels with polyaniline showed better cytocompatibility than QCS hydrogel. The electroactive hydrogels could significantly enhance the proliferation of C2C12 myoblasts compared to QCS hydrogel. This work opens the way to fabricate in situ forming antibacterial and electroactive degradable hydrogels as a new class of bioactive scaffolds for tissue regeneration applications. Copyright © 2015 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  17. Adsorption of crude oil from aqueous solution by hydrogel of chitosan based polyacrylamide prepared by radiation induced graft polymerization.

    PubMed

    Sokker, H H; El-Sawy, Naeem M; Hassan, M A; El-Anadouli, Bahgat E

    2011-06-15

    The adsorption of crude oil (initial concentration 0.5-30 g/L) from aqueous solution using hydrogel of chitosan based polyacrylamide (PAM) prepared by radiation induced graft polymerization has been investigated. The prepared hydrogel was characterized by FTIR and SEM micrographs. The experiments were carried out as a function of different initial concentrations of oil residue, acrylamide concentration, contact time and pH to determine the optimum condition for the adsorption of residue oil from aqueous solution and sea water. The results obtained showed that the hydrogel prepared at concentration of 40% acrylamide (AAm) and at a radiation dose of 5 kGy has high removal efficiency of crude oil 2.3g/g at pH 3. Equilibrium studies have been carried out to determine the capacity of the hydrogel for adsorption of crude oil, Langmuir and Freundlich adsorption models were applied to describe the experimental isotherms and isotherms constants. Equilibrium data were found to fit very well with both Freundlich and Langmuir models. Also the adsorption of oil onto the hydrogel behaves as a pseudo-second-order kinetic models rather than the pseudo-first-order kinetic model. Copyright © 2011 Elsevier B.V. All rights reserved.

  18. Evaluation of the flocculation performance of carboxymethyl chitosan-graft-polyacrylamide, a novel amphoteric chemically bonded composite flocculant.

    PubMed

    Yang, Zhen; Yuan, Bo; Huang, Xin; Zhou, Junyu; Cai, Jun; Yang, Hu; Li, Aimin; Cheng, Rongshi

    2012-01-01

    In the present work, a novel amphoteric chemically bonded composite flocculant (carboxymethyl chitosan-graft-polyacrylamide, denoted as CMC-g-PAM) was successfully prepared and used to flocculate the kaolin suspension. The flocculation performance of CMC-g-PAM in acidic, neutral, and alkaline conditions was systematically evaluated by light scattering in combination with fractal theory, as well as by traditional turbidity and zeta potential measurements. Based on the experimental facts from in situ size and fractal dimension measurements, different flocculation mechanisms play key roles at various pH levels, resulting in substantially varied flocculation kinetic processes under three pH conditions. In acidic condition, patching was the main mechanism involved in the opposite zeta potential between CMC-g-PAM and the kaolin suspension. A flat configuration was favored when the polymeric flocculant was adsorbed onto the particle surface, leading to a slower initial floc growth rate but larger and denser flocs. Bridging was the dominant mechanism in neutral and alkaline conditions. A faster initial rate of bridging resulted in smaller and more open floc structures. A rearrangement process in neutral pH subsequently led to more compact flocs, whereas no restructuration of flocs occurred in alkaline conditions because of the electrostatic repulsion of the same negative charges on the flocculant and particles.

  19. Photo-initiated grafting of gelatin/N-maleic acyl-chitosan to enhance endothelial cell adhesion, proliferation and function on PLA surface.

    PubMed

    Zhu, Aiping; Zhao, Feng; Ma, Teng

    2009-07-01

    Vascular graft surface properties significantly affect adhesion, growth and function of endothelial cells (ECs). The bulk degradation property of poly(lactic acid) (PLA) makes it possible for it to be replaced by cellular materials and PLA is desirable as a scaffold material for vascular grafts. However, PLA has an unfavorable surface property for EC adhesion and proliferation due to the lack of a selective cell adhesion motif. Photo-initiated surface-grafting polymerization is a promising method for immobilizing certain biomacromolecules on material surfaces without compromising bulk properties. N-Maleic acyl-chitosan (NMCS) is a novel biocompatible amphiphilic derivative of chitosan with double bonds and can be initiated by ultraviolet light. In this study, gelatin was complexed with NMCS via hydrophobic interaction, and gel/NMCS complex thus formed was then grafted on the PLA surface to improve EC biocompatibility. X-ray photoelectron and Fourier transform infrared spectroscopy, and water contact angle measurement confirmed immobilization of the gel/NMCS complex on PLA surface. Moreover, the gel/NMCS modified PLA enhanced human umbilical vein endothelial cell (HUVEC) spreading and flattening, and promoted the expression of more structured CD31 and vWF compared to unmodified PLA film. Compared to the unmodified PLA surface, the HUVECs on the modified PLA surface had elevated uptake of acetylated low-density lipoprotein, and maintained the ability to modulate metabolic activity upon exposure to shear stress at 5dyncm(-2) by up-regulating nitric oxide and prostacyclin production. Cell retention was 1.6 times higher on the gel/NMCS-PLA surface, demonstrating its improved potential for hemocompatibility. These results indicate that photo-initiated surface-grafting of the biomimetic gel/NMCS complex is an effective method to modify material surfaces as vascular grafts.

  20. Chitosan-graft-mPEG based 5-Fluorouracil loaded polymeric nanoparticles for tumor targeted drug delivery.

    PubMed

    Antoniraj, M Gover; Ayyavu, Mahesh; Henry, Linda Jeeva Kumari; Nageshwar Rao, Goutham; Natesan, Subramanian; Sundar, D Sathish; Kandasamy, Ruckmani

    2017-08-24

    Biodegradable materials like chitosan (CH) and methoxy polyethylene glycol (mPEG) are widely being used as drug delivery carriers for various therapeutic applications. In the present study, copolymer (CH-g-mPEG) of chitosan and carboxylic acid terminated mPEG was synthesized by carbodiimide mediated acid amine reaction. The resultant hydrophilic copolymer was characterized by FTIR and (1)H NMR studies, revealing its relevant functional bands and proton peaks respectively. Blank polymeric nanoparticles (B-PNPs) and 5-Fluorouracil loaded polymeric nanoparticles (5-FU-PNPs) were formulated by ionic gelation method. Furthermore, folic acid functionalized FA-PNPs and FA-5-FU-PNPs were prepared for folate receptor targeted drug delivery. FA-5-FU-PNPs were characterized by particle size, zeta potential and in vitro drug release studies, resulting in 197.7 nm, +29.9 mv and sustained drug release of 88% in 24 h respectively. Cytotoxicity studies were performed for FA-PNPs and FA-5-FU-PNPs in MCF-7 cell line, which exhibited a cell viability of 80% and 41%, respectively. In vitro internalization studies were carried out for 5-FU-PNPs and FA-5-FU-PNPs which demonstrated increased cellular uptake of FA-5-FU-PNPs by receptor-mediated transport. Significant (p < 0.01) reduction (1.5-fold) of reactive oxygen species (ROS) accumulation was observed in lipopolysaccharides-stimulated RAW264.7 macrophages, revealing its potent antioxidant property. From the obtained results, it is concluded that folic acid functionalization of 5-FU-PNPs is an ideal approach for sustained and targeted drug delivery, thereby influencing better therapeutic effect.

  1. 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.

  2. The effect of layer-by-layer chitosan-hyaluronic acid coating on graft-to-bone healing of a poly(ethylene terephthalate) artificial ligament.

    PubMed

    Li, Hong; Ge, Yunsheng; Zhang, Pengyun; Wu, Lingxiang; Chen, Shiyi

    2012-01-01

    Surface coating with an organic layer-by-layer self-assembled template of chitosan and hyaluronic acid on a poly(ethylene terephthalate) (PET) artificial ligament was designed for the promotion and enhancement of graft-to-bone healing after artificial ligament implantation in a bone tunnel. The results of in vitro culturing of MC3T3-E1 mouse osteoblastic cells supported the hypothesis that the layer-by-layer coating of chitosan and hyaluronic acid could promote the cell compatibility of grafts and could promote osteoblast proliferation. A rabbit extra-articular tendon-to-bone healing model was used to evaluate the effect of this kind of surface-modified stainless artificial ligament in vivo. The final results proved that this organic compound coating could significantly promote and enhance new bone formation at the graft-bone interface histologically and, correspondingly, the experimental group with coating had significantly higher biomechanical properties compared with controls at 8 weeks (P < 0.05).

  3. A comparison of eugenol and menthol on encapsulation characteristics with water-soluble quaternized β-cyclodextrin grafted chitosan.

    PubMed

    Phunpee, Sarunya; Saesoo, Somsak; Sramala, Issara; Jarussophon, Suwatchai; Sajomsang, Warayuth; Puttipipatkhachorn, Satit; Puttipipatkhajorn, Satit; Soottitantawat, Apinan; Ruktanonchai, Uracha Rungsardthong

    2016-03-01

    Two guest molecules (eugenol and (-)-menthol) were investigated on inclusion complex formation with water-soluble quaternized β-CD grafted with chitosan (QCD-g-CS). The inclusion complexes were prepared at varying mole ratios between eugenol or (-)-menthol and β-CD (substituted on QCD-g-CS) by a conventional shaking method and obtained as solid powder by freeze-drying process. The results showed that encapsulation efficiency %EE decreased with increasing of initial eugenol or (-)-menthol loading whereas %loading increased with increasing of initial eugenol or (-)-menthol loading. The results indicated that inclusion complex formation between eugenol and QCD-g-CS was more favorable than that of (-)-menthol. To clarify this mechanism, molecular dynamics simulations were performed to explore their binding energy, solvation energy and total free energy of those complexes. It was found that the total free energy (ΔG) of eugenol and (-)-menthol against QCD-g-CS (mole ratio of 1) in water-explicit system were -2108.91 kJ/mol and -344.45 kJ/mol, respectively. Moreover, molecular dynamic simulation of eugenol absorbed on surface QCD-g-CS (-205.73 kJ/mol) was shown to have a higher negative value than that of (-)-menthol on QCD-gCS (3182.31 kJ/mol). Furthermore, the release characteristics of the encapsulated powder were also investigated in simulated saliva pH 6.8 at 32 °C. The results suggested that (-)-menthol had higher release rate from the complexes than eugenol. In all cases, the release characteristics for those guest molecules could be characterized by the limited-diffusion kinetics.

  4. High-Performance Capacitive Deionization Disinfection of Water with Graphene Oxide-graft-Quaternized Chitosan Nanohybrid Electrode Coating.

    PubMed

    Wang, Yilei; El-Deen, Ahmed G; Li, Peng; Oh, Bernice H L; Guo, Zanru; Khin, Mya Mya; Vikhe, Yogesh S; Wang, Jing; Hu, Rebecca G; Boom, Remko M; Kline, Kimberly A; Becker, David L; Duan, Hongwei; Chan-Park, Mary B

    2015-10-27

    Water disinfection materials should ideally be broad-spectrum-active, nonleachable, and noncontaminating to the liquid needing sterilization. Herein, we demonstrate a high-performance capacitive deionization disinfection (CDID) electrode made by coating an activated carbon (AC) electrode with cationic nanohybrids of graphene oxide-graft-quaternized chitosan (GO-QC). Our GO-QC/AC CDID electrode can achieve at least 99.9999% killing (i.e., 6 log reduction) of Escherichia coli in water flowing continuously through the CDID cell. Without the GO-QC coating, the AC electrode alone cannot kill the bacteria and adsorbs a much smaller fraction (<82.8 ± 1.8%) of E. coli from the same biocontaminated water. Our CDID process consists of alternating cycles of water disinfection followed by electrode regeneration, each a few minutes duration, so that this water disinfection process can be continuous and it only needs a small electrode voltage (2 V). With a typical brackish water biocontamination (with 10(4) CFU mL(-1) bacteria), the GO-QC/AC electrodes can kill 99.99% of the E. coli in water for 5 h. The disinfecting GO-QC is securely attached on the AC electrode surface, so that it is noncontaminating to water, unlike many other chemicals used today. The GO-QC nanohybrids have excellent intrinsic antimicrobial properties in suspension form. Further, the GO component contributes toward the needed surface conductivity of the CDID electrode. This CDID process offers an economical method toward ultrafast, contaminant-free, and continuous killing of bacteria in biocontaminated water. The proposed strategy introduces a green in situ disinfectant approach for water purification.

  5. Uptake of Pb(II) and Cd(II) on Chitosan Microsphere Surface Successively Grafted by Methyl Acrylate and Diethylenetriamine.

    PubMed

    Zhang, Haifeng; Dang, Qifeng; Liu, Chengsheng; Cha, Dongsu; Yu, Zhenzhen; Zhu, Wenjing; Fan, Bing

    2017-03-29

    A novel adsorbent, CS-MA-DETA microspheres, for uptake of heavy metal ions from aqueous solutions was first fabricated via two-step grafting methyl acrylate (MA) and diethylenetriamine (DETA) onto chitosan (CS) microsphere surface in the absence of cross-linkers. CS-MA-DETA microspheres of 3.04 μm in mean diameter were of uniformly wrinkle-like topography sketched out by SEM, whose surface after decoration by MA and DETA was stable and beneficial to metal ion capture. Its chemical composition, microstructure, and thermal property were characterized by elemental analysis, FTIR, XRD, BET, and TGA techniques, and the achieved quantitative results mainly included C/N ratio (4.76), crystallinity (31.20%, 19.75% of CS), specific surface area (27.806 m(2) g(-1)), pore diameter (3.452 nm), and mass loss at the first stage (3%, around 10% of CS), which indicated a successful synthesis, well-defined structure, and good thermostability. Adsorption tests of CS-MA-DETA microspheres were performed in Pb(II) and/or Cd(II) solution(s) at various pH values, contact time, and initial concentrations, exhibiting an excellent adsorption capability. Its maximum adsorption capacity calculated by Langmuir model was 239.2 mg Pb(II)/g, or 201.6 mg Cd(II)/g, which was higher than those of most available CS-based adsorbents. Furthermore, several adsorption kinetic and isotherm models were employed to investigate its uptake behavior, implying that it was mainly a monolayer adsorption and chemisorption process. Five-cycle reusability tests demonstrated CS-MA-DETA microspheres could be repeatedly used without significant capacity loss (<10%). Additionally, several potential bonding modes and adsorption sites for both metal ions were also proposed. Overall, CS-MA-DETA microspheres with outstanding adsorption performance toward Pb(II) and/or Cd(II) might serve as a new absorbent for wastewater purification.

  6. Reusable nanocomposite of CoFe2O4/chitosan-graft-poly(acrylic acid) for removal of Ni(II) from aqueous solution

    NASA Astrophysics Data System (ADS)

    Nguyen, Van Cuong; Huynh, Thi Kim Ngoc

    2014-06-01

    In this paper, CoFe2O4/chitosan-graft-poly(acrylic acid) (CoFe2O4/CS-graft-PAA) nanocomposites were prepared successfully by coprecipitation of the compounds in alkaline solution and were used for removal of nickel (II) ions from aqueous solution. The sorption rate was affected significantly by the initial concentration of the solution, sorbent amount, and pH value of the solution. Batch experiments were conducted to investigate the adsorption capacity under different initial concentration (ranging from 25 to 150 mg L-1), solution pH (4.1, 5.3, 6.4 and 7.6), and contact time. These nanocomposites can be recycled conveniently from water with the assistance of an external magnet because of their exceptional properties. The prepared nanocomposites were characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), x-ray powder diffraction (XRD), and thermogravimetric analysis (TGA).

  7. Polymethylmethacrylate bone cements and additives: A review of the literature

    PubMed Central

    Arora, Manit; Chan, Edward KS; Gupta, Sunil; Diwan, Ashish D

    2013-01-01

    Polymethylmethacrylate (PMMA) bone cement technology has progressed from industrial Plexiglass administration in the 1950s to the recent advent of nanoparticle additives. Additives have been trialed to address problems with modern bone cements such as the loosening of prosthesis, high post-operative infection rates, and inflammatory reduction in interface integrity. This review aims to assess current additives used in PMMA bone cements and offer an insight regarding future directions for this biomaterial. Low index (< 15%) vitamin E and low index (< 5 g) antibiotic impregnated additives significantly address infection and inflammatory problems, with only modest reductions in mechanical strength. Chitosan (15% w/w PMMA) and silver (1% w/w PMMA) nanoparticles have strong antibacterial activity with no significant reduction in mechanical strength. Future work on PMMA bone cements should focus on trialing combinations of these additives as this may enhance favourable properties. PMID:23610754

  8. Effects of pore forming agents on chitosan-graft-poly(N-vinylpyrrolidone) hydrogel properties for use as a matrix for floating drug delivery

    NASA Astrophysics Data System (ADS)

    Budianto, E.; Al-Shidqi, M. F.; Cahyana, A. H.

    2017-07-01

    Eradicating H. pylori-based infection by using conventional oral dosage form of amoxicillin trihydrate finds difficulties to overcome rapid gastric retention time. Encapsulating amoxicillin trihydrate in floating drug delivery system may solve the problem. In this research, the floating drug delivery system of amoxicillin trihydrate encapsulated in floating chitosan-graft-poly(N-vinyl pyrrolidone) hydrogels containing CaCO3 and NaHCO3 as pore forming agents has been successfully prepared. Pore forming agents used was varied with the ratio of 10 to 25% pore forming agents to total mass of the used materials. The hydrogel were characterizedusing FTIR spectrophotometer and stereo microscope. As pore forming agents compositions increased, the porosity (%) and floating properties increased but followed by decrease in drug entrapment efficiency. Most of the floating hydrogels possessed floating ability longer than 180 min and the highest porosity was found in hydrogel containing 25% NaHCO3. Hydrogel containing CaCO3 showed sustained drug release profile than hydrogel containing NaHCO3. However, the optimum formulation was achieved at composition of 10% NaHCO3 with 57% of drug entrapped within the hydrogel and 43% drug released. The results of these studies show that NaHCO3 is an effective pore forming agents for chitosan-graft-poly(N-vinyl pyrrolidone) hydrogel preparation as compare to CaCO3.

  9. Poly(N-isopropylacrylamide) surface-grafted chitosan membranes as a new substrate for cell sheet engineering and manipulation.

    PubMed

    da Silva, Ricardo M P; López-Pérez, Paula M; Elvira, Carlos; Mano, João F; Román, Julio San; Reis, Rui L

    2008-12-15

    The immobilization of poly(N-isopropylacrylamide) (PNIPAAm) on chitosan membranes was performed in order to render membranes with thermo-responsive surface properties. The aim was to create membranes suitable for cell culture and in which confluent cell sheets can be recovered by simply lowering the temperature. The chitosan membranes were immersed in a solution of the monomer that was polymerized via radical initiation. The composition of the polymerization reaction solvent, which was a mixture of a chitosan non-solvent (isopropanol) and a solvent (water), provided a tight control over the chitosan membranes swelling capability. The different swelling ratio, obtained at different solvent composition of the reaction mixture, drives simultaneously the monomer solubility and diffusion into the polymeric matrix, the polymerization reaction rate, as well as the eventual chain transfer to the side substituents of the pyranosyl groups of chitosan. A combined analysis of the modified membranes chemistry by proton nuclear magnetic resonance ((1)H-NMR), Fourier transform spectroscopy with attenuated total reflection (FTIR-ATR) and X-ray photoelectron spectroscopy (XPS) showed that it was possible to control the chitosan modification yield and depth in the solvent composition range between 75% and 100% of isopropanol. Plasma treatment was also applied to the original chitosan membranes in order to improve cell adhesion and proliferation. Chitosan membranes, which had been previously subjected to oxygen plasma treatment, were then modified by means of the previously described methodology. A human fetal lung fibroblast cell line was cultured until confluence on the plasma-treated thermo-responsive chitosan membranes and cell sheets were harvested lowering the temperature.

  10. Efficient sorption of Cu(2+) by composite chelating sorbents based on potato starch-graft-polyamidoxime embedded in chitosan beads.

    PubMed

    Dragan, Ecaterina Stela; Apopei Loghin, Diana Felicia; Cocarta, Ana Irina

    2014-10-08

    Ionic composites based on cross-linked chitosan (CS) as matrix and poly(amidoxime) grafted on potato starch (AOX) as entrapped chelating resin were prepared as beads, for the first time in this work, by two strategies: (1) thorough mixing of previously prepared AOX in the CS solution followed by the bead formation and (2) thorough mixing of the potato starch-g-poly(acrylonitrile) (PS-g-PAN) copolymer in the initial CS solution, followed by bead formation, the amidoximation of the nitrile groups taking place inside the beads. Ionotropic gelation in tripolyphosphate was used to obtain the composite beads, and in situ covalent cross-linking by epichlorohydrin was carried out to stabilize the beads in the acidic pH range. Fourier transform infrared spectroscopy and the swelling ratio values in the acidic pH range confirmed the influence of the synthesis strategy on the structure of the CS/AOX composites. Scanning electron microscopy was employed to reveal the morphology of the novel composites, both before and after their loading with Cu(2+). The binding capacity of Cu(2+) ions as a function of sorbent composition, synthesis strategy, pH, sorbent dose, contact time, initial concentration of Cu(2+), and temperature was examined in batch mode. The main difference between the composites prepared with the two strategies consisted of the higher sorption capacity and the much faster settlement of the equilibrium sorption for the composite prepared by the in situ amidoximation of PS-g-PAN. The Langmuir, Freundlich, Temkin, Dubinin-Radushkevich, and Sips isotherms were applied to fit the sorption equilibrium data. The maximum equilibrium sorption capacity, qm, evaluated by the Langmuir model at 25 °C was 133.15 mg Cu(2+)/g for the CS/AOX composite beads prepared with the first strategy and 238.14 mg Cu(2+)/g for the CS/AOX composite beads prepared with the second strategy, at the same AOX content. The pseudo-second order kinetic model well fitted the sorption kinetics data

  11. Self-aggregated nanoparticles based on amphiphilic poly(lactic acid)-grafted-chitosan copolymer for ocular delivery of amphotericin B

    PubMed Central

    Zhou, Wenjun; Wang, Yuanyuan; Jian, Jiuying; Song, Shengfang

    2013-01-01

    Background The purpose of this study was to develop a self-aggregated nanoparticulate vehicle using an amphiphilic poly(lactic acid)-grafted-chitosan (PLA-g-CS) copolymer and to evaluate its potential for ocular delivery of amphotericin B. Methods A PLA-g-CS copolymer was synthesized via a “protection-graft-deprotection” procedure and its structure was confirmed by Fourier transform infrared spectroscopy, 1H nuclear magnetic resonance, and X-ray diffraction spectra. Amphotericin B-loaded nanoparticles based on PLA-g-CS (AmB/PLA-g-CS) were prepared by the dialysis method and characterized for particle size, zeta potential, and encapsulation efficiency. Studies of these AmB/PLA-g-CS nanoparticles, including their mucoadhesive strength, drug release properties, antifungal activity, ocular irritation, ocular pharmacokinetics, and corneal penetration were performed in vitro and in vivo. Results Fourier transform infrared spectroscopy, 1H nuclear magnetic resonance, and X-ray diffraction spectra showed that the PLA chains were successfully grafted onto chitosan molecules and that crystallization of chitosan was suppressed. The self-aggregated PLA-g-CS nanoparticles had a core-shell structure with an average particle size of approximately 200 nm and zeta potentials higher than 30 mV. Amphotericin B was incorporated into the hydrophobic core of the nanoparticles with high encapsulation efficiency. Sustained drug release from the nanoparticles was observed in vitro. The ocular irritation study showed no sign of irritation after instillation of the PLA-g-CS nanoparticles into rabbit eyes. The minimal inhibitory concentration of the AmB/PLA-g-CS nanoparticles showed antifungal activity similar to that of free amphotericin B against Candida albicans. The in vivo ocular pharmacokinetic study suggested that the PLA-g-CS nanoparticles have the advantage of prolonging residence time at the ocular surface. The corneal penetration study showed that the PLA-g-CS nanoparticles

  12. Development and In Vivo Evaluation of Small-Diameter Vascular Grafts Engineered by Outgrowth Endothelial Cells and Electrospun Chitosan/Poly(ɛ-Caprolactone) Nanofibrous Scaffolds

    PubMed Central

    Zhou, Min; Qiao, Wei; Liu, Zhao; Shang, Tao; Qiao, Tong

    2014-01-01

    Successful engineering of a small-diameter vascular graft is still a challenge despite numerous attempts for decades. The present study aimed at developing a tissue-engineered vascular graft (TEVG) using autologous outgrowth endothelial cells (OECs) and a hybrid biodegradable polymer scaffold. OECs were harvested from canine peripheral blood and proliferated in vitro, as well as identified by immunofluorescent staining. Electrospun hybrid chitosan/poly(ɛ-caprolactone) (CS/PCL) nanofibers were fabricated and served as vascular scaffolds. TEVGs were constructed in vitro by seeding OECs onto CS/PCL scaffolds, and then implanted into carotid arteries of cell-donor dogs (n=6). After 3 months of implantation, 5 out of 6 of TEVGs remained patent as compared with 1 out of 6 of unseeded grafts kept patent. Histological and immunohistochemical analyses of the TEVGs retrieved at 3 months revealed the regeneration of endothelium, and the presence of collagen and elastin. OECs labeled with fluorescent dye before implantation were detected in the retrieved TEVGs, indicating that the OECs participated in the vascular tissue regeneration. Biomechanical testing of TEVGs showed good mechanical properties that were closer to native carotid arteries. RT-PCR and western blot analysis demonstrated that TEVGs had favorable biological functional properties resembling native arteries. Overall, this study provided a new strategy to develop small-diameter TEVGs with excellent biocompatibility and regeneration ability. PMID:23902162

  13. Preparation of porous carboxymethyl chitosan grafted poly (acrylic acid) superabsorbent by solvent precipitation and its application as a hemostatic wound dressing.

    PubMed

    Chen, Yu; Zhang, Yong; Wang, Fengju; Meng, Weiwei; Yang, Xinlin; Li, Peng; Jiang, Jianxin; Tan, Huimin; Zheng, Yongfa

    2016-06-01

    The volume phase transition of a hydrogel initiated by shrinking may result in complex patterns on its surface. Based on this unique property of hydrogel, we have developed a novel solvent precipitation method to prepare a kind of novel superabsorbent polymers with excellent hemostatic properties. A porous carboxymethyl chitosan grafted poly (acrylic acid) (CMCTS-g-PAA) superabsorbent polymer was prepared by precipitating CMCTS-g-PAA hydrogel with ethanol. Its potential application in hemostatic wound dressing was investigated. The results indicate that the modified superabsorbent polymer is non-cytotoxic. It showed a high swelling capacity and better hemostatic performance in the treatments of hemorrhage model of ear artery, arteria cruralis and spleen of the New Zealand white rabbit than the unmodified polymer and other commonly used clinic wound dressings. The hemostatic mechanism of the porous CMCTS-g-PAA polymer was also discussed.

  14. Characterization of the paclitaxel loaded chitosan graft Pluronic F127 copolymer micelles conjugate with a DNA aptamer targeting HER-2 overexpressing breast cancer cells

    NASA Astrophysics Data System (ADS)

    Thach Nguyen, Kim; Nguyen, Thu Ha; Do, Dinh Ho; Huan Le, Quang

    2017-03-01

    In this work we report the isolation of DNA aptamer that is specifically bound to a HER-2 overexpressing SK-BR-3 human breast cancer cell line, using SELEX strategy. Paclitaxel (PTX) loaded chitosan graft Pluronic F127 copolymer micelles conjugate with a DNA aptamer was synthesized and its structure was confirmed by TEM image. This binary mixed system consisting of DNA aptamer modified Pluronic F127 and chitosan could enhance PTX loading capacity and increase micelle stability. Morphology images confirmed the existence of PTX micelles, with an average size of approximately 86.22 ± 1.45 nm diameters. Drug release profile showed that the PTX conjugate maintained a sustained PTX release. From in vitro cell experiment it was shown that 89%–93%, 50%–58%, 55%–62%, 24%–28% and 2%–7% of the SK-BR-3, NS-VN-67, LH-VN-48, HT-VN-26 and NV-VN-31, respectively, were dead after 6–48 h. These results demonstrated a novel DNA aptamer-micelle assembly for efficient detection and a system for the delivery of PTX targeting specific HER-2 overexpressing. We have also successfully cultivated cancer tissues of explants from Vietnamese patients on a type I collagen substrate. The NS-VN-67, LH-VN-48, HT-VN-26 and NV-VN-31cell lines were used as cellular model sources for the study of chemotherapy drug in cancer.

  15. Synthesis of poly(ethylene glycol)-graft-chitosan and using as ligand for fabrication of water-soluble quantum dots.

    PubMed

    Jiang, Zhenchao; Zhao, Chunbao; Liu, Xiaoheng

    2014-03-01

    The synthesis of water-soluble, stable and biocompatible quantum dots (QDs) is of crucial importance for nanobiotechnology. A chitosan derivative, poly(ethylene glycol)-graft-chitosan (PEG-g-CS), was successfully synthesized and employed as ligand for the growth of CdSe QDs in aqueous solution. The bivalent Cd(2+) ions can coordinate with multiple amino-groups, thus they act as both inter- and intramolecular cross-linking agents. When the concentration of Cd(2+) was 0.2 mmol/L, the CdSe/PEG-g-CS aggregates formed an irregular cross-linked network; when the concentration was 1 mmol/L, a phenomenon of micro-phase separation emerged as a result of enrichment of CS phase; when the concentration was 2 mmol/L, spherical nanohybrids with the size of 30-50 nm were obtained. Moreover, a possible mechanism was proposed for the formation of CdSe/PEG-g-CS aggregates. Meantime, in vitro 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) cytotoxicity tests against HepG2 cells were carried out, the corresponding results suggested that the CdSe QDs prepared using PEG-g-CS as ligand displayed very low cytotoxicity. Therefore, these water-soluble QD-polymer hybrids are expected to find promising applications in medical field.

  16. Microspheres Assembled from Chitosan-Graft-Poly(lactic acid) Micelle-Like Core-Shell Nanospheres for Distinctly Controlled Release of Hydrophobic and Hydrophilic Biomolecules.

    PubMed

    Niu, Xufeng; Liu, Zhongning; Hu, Jiang; Rambhia, Kunal J; Fan, Yubo; Ma, Peter X

    2016-07-01

    To simultaneously control inflammation and facilitate dentin regeneration, a copolymeric micelle-in-microsphere platform is developed in this study, aiming to simultaneously release a hydrophobic drug to suppress inflammation and a hydrophilic biomolecule to enhance odontogenic differentiation of dental pulp stem cells in a distinctly controlled fashion. A series of chitosan-graft-poly(lactic acid) copolymers is synthesized with varying lactic acid and chitosan weight ratios, self-assembled into nanoscale micelle-like core-shell structures in an aqueous system, and subsequently crosslinked into microspheres through electrostatic interaction with sodium tripolyphosphate. A hydrophobic biomolecule either coumarin-6 or fluocinolone acetonide (FA) is encapsulated into the hydrophobic cores of the micelles, while a hydrophilic biomolecule either bovine serum albumin or bone morphogenetic protein 2 (BMP-2) is entrapped in the hydrophilic shells and the interspaces among the micelles. Both hydrophobic and hydrophilic biomolecules are delivered with distinct and tunable release patterns. Delivery of FA and BMP-2 simultaneously suppresses inflammation and enhances odontogenesis, resulting in significantly enhanced mineralized tissue regeneration. This result also demonstrates the potential for this novel delivery system to deliver multiple therapeutics and to achieve synergistic effects.

  17. Synthesis and characterization of poly(maleic acid)-grafted crosslinked chitosan nanomaterial with high uptake and selectivity for Hg(II) sorption.

    PubMed

    Ge, Huacai; Hua, Tingting

    2016-11-20

    Chitosan-poly(maleic acid) nanomaterial (PMACS) with the size of 400-900nm was synthesized by grafting poly(maleic acid) onto chitosan and then crosslinking with glutaraldehyde. The synthesis conditions were optimized. The structure and morphology of PMACS were characterized by FT-IR, XRD, SEM and TGA. PMACS was used to adsorb some heavy metal ions such as Hg(II), Pb(II), Cu(II), Cd(II), Co(II), and Zn(II). The results indicated that PMACS had selectivity for Hg(II) sorption. The effects of various variables for sorption of Hg(II) were further explored. The maximum capacity for Hg(II) sorption was found to be 1044mgg(-1) at pH 6.0, which could compare with the maximal value of the recently reported other sorbents. The sorption followed the pseudo-second-order kinetics and Langmuir isotherm models. The rising of temperature benefited the uptake and the sorption was a spontaneous chemical process. The sorbent could be reused with EDTA. Hence, the nanomaterial would be used as a selective and high uptake sorbent in the removal of Hg(II) from effluents. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. Synthesis and characterization of carboxyl terminated poly(methacrylic acid) grafted chitosan/bentonite composite and its application for the recovery of uranium(VI) from aqueous media.

    PubMed

    Anirudhan, T S; Rijith, S

    2012-04-01

    A novel adsorbent poly(methacrylic acid)-grafted chitosan/bentonite (CTS-g-PMAA/Bent) composite was prepared through graft copolymerization reaction of methacrylic acid and chitosan in the presence of bentonite (Bent) and N,N'- methylenebisacrylamide as a crosslinker. The composite was well characterized using FTIR, XRD, XPS, SEM-EDS, surface area and zeta potential analyzers. The adsorption behavior of the composite toward uranium(VI) from aqueous media was studied under varying operating conditions of pH, concentration of U(VI), contact time, adsorbent dose and temperature. The optimum pH range for U(VI) adsorption was 5.5 at 30 °C. Concentration and temperature dependent rate constants were evaluated using pseudo-second-order kinetic model. The equilibrium data were correlated with the Langmuir isotherm model with an endothermic behavior. The equilibrium U(VI) sorption capacity was estimated to be 117.2 mg g(-1) at 30 °C. For the quantitative recovery of 100 mg L(-1) U(VI) from 1.0 L simulated nuclear industry wastewater, a minimum adsorbent dosage of 2.0 g CTS-g-PMAA/Bent was required. The calculated energy of activation (E(a) = 47.83 kJ/mol) was positively correlated with chemical adsorption process. The values of enthalpy, entropy and free energy of activation were calculated to explain the nature of adsorption process. Adsorption-desorption experiments over four cycles illustrate the feasibility of the repeated uses of this composite for the extraction of U(VI) from aqueous solutions. Copyright © 2011 Elsevier Ltd. All rights reserved.

  19. Functionalization of Magnetic Chitosan Particles for the Sorption of U(VI), Cu(II) and Zn(II)—Hydrazide Derivative of Glycine-Grafted Chitosan

    PubMed Central

    Hamza, Mohammed F.; Aly, Mohsen M.; Abdel-Rahman, Adel A.-H.; Ramadan, Samar; Raslan, Heba; Wang, Shengye; Vincent, Thierry; Guibal, Eric

    2017-01-01

    A new magnetic functionalized derivative of chitosan is synthesized and characterized for the sorption of metal ions (environmental applications and metal valorization). The chemical modification of the glycine derivative of chitosan consists of: activation of the magnetic support with epichlorohydrin, followed by reaction with either glycine to produce the reference material (i.e., Gly sorbent) or glycine ester hydrochloride, followed by hydrazinolysis to synthesize the hydrazide functionalized sorbent (i.e., HGly sorbent). The materials are characterized by titration, elemental analysis, FTIR analysis (Fourrier-transform infrared spectrometry), TGA analysis (thermogravimetric analysis) and with SEM-EDX (scanning electron microscopy coupled to energy dispersive X-ray analysis). The sorption performances for U(VI), Cu(II), and Zn(II) are tested in batch systems. The sorption performances are compared for Gly and HGly taking into account the effect of pH, the uptake kinetics (fitted by the pseudo-second order rate equation), and the sorption isotherms (described by the Langmuir and the Sips equations). The sorption capacities of the modified sorbent reach up to 1.14 mmol U g−1, 1.69 mmol Cu g−1, and 0.85 mmol Zn g−1. In multi-metal solutions of equimolar concentration, the chemical modification changes the preferences for given metal ions. Metal ions are desorbed using 0.2 M HCl solutions and the sorbents are re-used for five cycles of sorption/desorption without significant loss in performances. PMID:28772896

  20. Long-term outcome of the repair of 50 mm long median nerve defects in rhesus monkeys with marrow mesenchymal stem cells-containing, chitosan-based tissue engineered nerve grafts.

    PubMed

    Hu, Nan; Wu, Hong; Xue, Chengbin; Gong, Yanpei; Wu, Jian; Xiao, Zhaoqun; Yang, Yumin; Ding, Fei; Gu, Xiaosong

    2013-01-01

    Despite great progress in the fields of tissue engineering and stem cell therapy, the translational and preclinical studies are required to accelerate the clinical application of tissue engineered nerve grafts, as an alternative to autologous nerve grafts, for peripheral nerve repair. Rhesus monkeys (non-human primates) are more clinically relevant and more suitable for scaling up to humans as compared to other mammalians. Based on this premise, and considering a striking similarity in the anatomy and function between human and monkey hands, here we used chitosan/PLGA-based, autologous marrow mesenchymal stem cells (MSCs)-containing tissue engineered nerve grafts (TENGs) for bridging a 50-mm long median nerve defect in rhesus monkeys. At 12 months after grafting, locomotive activity observation, electrophysiological assessments, and FG retrograde tracing tests indicated that the recovery of nerve function by TENGs was more efficient than that by chitosan/PLGA scaffolds alone; histological and morphometric analyses of regenerated nerves further confirmed that the morphological reconstruction by TENGs was close to that by autografts and superior to that by chitosan/PLGA scaffolds alone. In addition, blood test and histopathological examination demonstrated that TENGs featured by addition of autologous MSCs could be safely used in the primate body. These findings suggest the efficacy of our developed TENGs for peripheral nerve regeneration and their promising perspective for clinical applications. Copyright © 2012 Elsevier Ltd. All rights reserved.

  1. Use of tissue-engineered nerve grafts consisting of a chitosan/poly(lactic-co-glycolic acid)-based scaffold included with bone marrow mesenchymal cells for bridging 50-mm dog sciatic nerve gaps.

    PubMed

    Ding, Fei; Wu, Jian; Yang, Yumin; Hu, Wen; Zhu, Qi; Tang, Xin; Liu, Jie; Gu, Xiaosong

    2010-12-01

    Bone marrow mesenchymal cells (MSCs) have attracted increasing research interest due to their possible use as support cells for nerve tissue-engineering approaches. We developed a novel design of tissue-engineered nerve grafts consisting of a chitosan/poly(lactic-co-glycolic acid) (PLGA)-based neural scaffold included with autologous MSCs. The graft was used as an alternative to nerve autografts for bridging 50-mm-long gaps in dog sciatic nerve, and the repair outcome at 6 months after nerve grafting was evaluated by a combination of electrophysiological assessment, FluoroGold retrograde tracing, and histological investigation to regenerated nerve tissue and reinnervated target muscle. The experimental results indicated that introduction of autologous MSCs to the chitosan/PLGA-based neural scaffold promoted sciatic nerve regeneration and functional recovery, demonstrating significant efficacy that was, to a certain degree, close to that by nerve autografting, a gold standard for treating large peripheral nerve gaps, and better than that by grafting with the chitosan/PLGA-based scaffold alone.

  2. 21 CFR 886.1385 - Polymethylmethacrylate (PMMA) diagnostic contact lens.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Polymethylmethacrylate (PMMA) diagnostic contact... Polymethylmethacrylate (PMMA) diagnostic contact lens. (a) Identification. A polymethylmethacrylate (PMMA) diagnostic contact lens is a device that is a curved shell of PMMA intended to be applied for a short period of...

  3. 21 CFR 886.1385 - Polymethylmethacrylate (PMMA) diagnostic contact lens.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Polymethylmethacrylate (PMMA) diagnostic contact... Polymethylmethacrylate (PMMA) diagnostic contact lens. (a) Identification. A polymethylmethacrylate (PMMA) diagnostic contact lens is a device that is a curved shell of PMMA intended to be applied for a short period of...

  4. 21 CFR 886.1385 - Polymethylmethacrylate (PMMA) diagnostic contact lens.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Polymethylmethacrylate (PMMA) diagnostic contact... Polymethylmethacrylate (PMMA) diagnostic contact lens. (a) Identification. A polymethylmethacrylate (PMMA) diagnostic contact lens is a device that is a curved shell of PMMA intended to be applied for a short period of...

  5. 21 CFR 886.1385 - Polymethylmethacrylate (PMMA) diagnostic contact lens.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Polymethylmethacrylate (PMMA) diagnostic contact... Polymethylmethacrylate (PMMA) diagnostic contact lens. (a) Identification. A polymethylmethacrylate (PMMA) diagnostic contact lens is a device that is a curved shell of PMMA intended to be applied for a short period of...

  6. 21 CFR 886.1385 - Polymethylmethacrylate (PMMA) diagnostic contact lens.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Polymethylmethacrylate (PMMA) diagnostic contact... Polymethylmethacrylate (PMMA) diagnostic contact lens. (a) Identification. A polymethylmethacrylate (PMMA) diagnostic contact lens is a device that is a curved shell of PMMA intended to be applied for a short period of...

  7. One pot synthesis of chitosan grafted quaternized resin for the removal of nitrate and phosphate from aqueous solution.

    PubMed

    Banu, H Thagira; Meenakshi, Sankaran

    2017-03-10

    The present study deals with the synthesis of chitosan quaternized resin for efficient removal of nitrate and phosphate from aqueous solution. The resin was characterized with FTIR, SEM with EDX and XRD. Batch method was carried out to optimize various parameters such as contact time, initial concentration of nitrate and phosphate, dosage, pH, co-anions and temperature on the adsorption capacity of the adsorbent. The adsorption process illustrated that the Freundlich isotherm and the pseudo-second order are the best fitted models for the sorption of both anions. The respective negative values of ΔH° and ΔG° revealed that the adsorption of both the anions were exothermic and spontaneous. The removal efficiency of nitrate and phosphate on chitosan quaternized resin were 78% and 90% respectively with 0.1g of adsorbent and the initial concentration as 100mg/L. Nitrate and phosphate anions adsorbed effectively on chitosan quaternized resin by replacing Cl(-) ions from quaternary site through electrostatic attraction as well as ion-exchange mechanism. Hydrogen bonding also played important role in adsorption process. Even after 7th regeneration cycle the adsorbent retained its adsorption capacity as 23.7mg/g and 30.4mg/g for both nitrate and phosphate respectively.

  8. Sardine oil loaded vanillic acid grafted chitosan microparticles, a new functional food ingredient: attenuates myocardial oxidative stress and apoptosis in cardiomyoblast cell lines (H9c2).

    PubMed

    Vishnu, K V; Ajeesh Kumar, K K; Chatterjee, Niladri S; Lekshmi, R G K; Sreerekha, P R; Mathew, Suseela; Ravishankar, C N

    2017-08-02

    Fish oil has been widely recognized as an excellent dietary source of polyunsaturated n-3 fatty acids such as EPA and DHA. However, it can undergo oxidation easily resulting in the formation of toxic off flavor compounds such as hydroperoxides. These compounds adversely affect the nutritional quality and may induce several stress reactions in body. To solve this problem, a new antioxidant bio-material, vanillic acid-grafted chitosan (Va-g-Ch), was synthesized and used as a wall material for microencapsulation of fish oil. The sardine oil loaded Va-g-Ch microparticles could be a potential functional food ingredient considering the numerous health benefits of fish oil, chitosan, and vanillic acid. The current study aimed to investigate the possible protective effect of sardine oil-loaded Va-g-Ch microparticles against doxorubicin-induced cardiotoxicity and the underlying mechanisms. In vitro cytotoxicity evaluation was conducted using H9c2 cardiomyocytes. MTT assay revealed that effective cytoprotective effect was induced by a sample concentration of 12.5 μg/mL. Results of apoptosis by double fluorescent staining with acridine orange/ethidium bromide and caspase-3 evaluation by ELISA substantiated the above findings. Further, flow cytometric determination of membrane potential, relative expression of NF-κB by PCR, and ROS determination using DCFH-DA also confirmed the protective effect of encapsulated sardine oil against doxorubicin-induced cardiotoxicity. NF-κB expression was down-regulated nearly by 50% on cells treated with encapsulated sardine oil. Altogether, the results revealed that sardine oil-loaded Va-g-Ch microparticles demonstrated potential cell protection against doxorubicin-induced oxidative stress.

  9. Tissue-Engineered Small Diameter Arterial Vascular Grafts from Cell-Free Nanofiber PCL/Chitosan Scaffolds in a Sheep Model

    PubMed Central

    Fukunishi, Takuma; Best, Cameron A.; Sugiura, Tadahisa; Shoji, Toshihiro; Yi, Tai; Udelsman, Brooks; Ohst, Devan; Ong, Chin Siang; Zhang, Huaitao; Shinoka, Toshiharu; Breuer, Christopher K.; Johnson, Jed; Hibino, Narutoshi

    2016-01-01

    Tissue engineered vascular grafts (TEVGs) have the potential to overcome the issues faced by existing small diameter prosthetic grafts by providing a biodegradable scaffold where the patient’s own cells can engraft and form functional neotissue. However, applying classical approaches to create arterial TEVGs using slow degrading materials with supraphysiological mechanical properties, typically results in limited host cell infiltration, poor remodeling, stenosis, and calcification. The purpose of this study is to evaluate the feasibility of novel small diameter arterial TEVGs created using fast degrading material. A 1.0mm and 5.0mm diameter TEVGs were fabricated with electrospun polycaprolactone (PCL) and chitosan (CS) blend nanofibers. The 1.0mm TEVGs were implanted in mice (n = 3) as an unseeded infrarenal abdominal aorta interposition conduit., The 5.0mm TEVGs were implanted in sheep (n = 6) as an unseeded carotid artery (CA) interposition conduit. Mice were followed with ultrasound and sacrificed at 6 months. All 1.0mm TEVGs remained patent without evidence of thrombosis or aneurysm formation. Based on small animal outcomes, sheep were followed with ultrasound and sacrificed at 6 months for histological and mechanical analysis. There was no aneurysm formation or calcification in the TEVGs. 4 out of 6 grafts (67%) were patent. After 6 months in vivo, 9.1 ± 5.4% remained of the original scaffold. Histological analysis of patent grafts demonstrated deposition of extracellular matrix constituents including elastin and collagen production, as well as endothelialization and organized contractile smooth muscle cells, similar to that of native CA. The mechanical properties of TEVGs were comparable to native CA. There was a significant positive correlation between TEVG wall thickness and CD68+ macrophage infiltration into the scaffold (R2 = 0.95, p = 0.001). The fast degradation of CS in our novel TEVG promoted excellent cellular infiltration and neotissue formation

  10. Bridging defects in chronic spinal cord injury using peripheral nerve grafts combined with a chitosan-laminin scaffold and enhancing regeneration through them by co-transplantation with bone-marrow-derived mesenchymal stem cells: Case series of 14 patients

    PubMed Central

    Amr, Sherif M.; Gouda, Ashraf; Koptan, Wael T.; Galal, Ahmad A.; Abdel-Fattah, Dina Sabry; Rashed, Laila A.; Atta, Hazem M.; Abdel-Aziz, Mohammad T.

    2014-01-01

    Objective To investigate the effect of bridging defects in chronic spinal cord injury using peripheral nerve grafts combined with a chitosan-laminin scaffold and enhancing regeneration through them by co-transplantation with bone-marrow-derived mesenchymal stem cells. Methods In 14 patients with chronic paraplegia caused by spinal cord injury, cord defects were grafted and stem cells injected into the whole construct and contained using a chitosan-laminin paste. Patients were evaluated using the International Standards for Classification of Spinal Cord Injuries. Results Chitosan disintegration leading to post-operative seroma formation was a complication. Motor level improved four levels in 2 cases and two levels in 12 cases. Sensory-level improved six levels in two cases, five levels in five cases, four levels in three cases, and three levels in four cases. A four-level neurological improvement was recorded in 2 cases and a two-level neurological improvement occurred in 12 cases. The American Spinal Impairment Association (ASIA) impairment scale improved from A to C in 12 cases and from A to B in 2 cases. Although motor power improvement was recorded in the abdominal muscles (2 grades), hip flexors (3 grades), hip adductors (3 grades), knee extensors (2–3 grades), ankle dorsiflexors (1–2 grades), long toe extensors (1–2 grades), and plantar flexors (0–2 grades), this improvement was too low to enable them to stand erect and hold their knees extended while walking unaided. Conclusion Mesenchymal stem cell-derived neural stem cell-like cell transplantation enhances recovery in chronic spinal cord injuries with defects bridged by sural nerve grafts combined with a chitosan-laminin scaffold. PMID:24090088

  11. Pharmacological performance of novel poly-(ionic liquid)-grafted chitosan-N-salicylidene Schiff bases and their complexes.

    PubMed

    Elshaarawy, Reda F M; Refaee, Ayaat A; El-Sawi, Emtithal A

    2016-08-01

    In our endeavor to develop a new class of pharmacological candidates with antimicrobial and anticancer efficacy, a series of biopolymeric chitosan Schiff bases bearing salicylidene ionic liquid (IL-Sal) brushes (ILCSB1-3, poly-(GlcNHAc-GlcNH2-(GlcN-Sal-IL)) was successfully synthesized by adopting efficient synthetic routes. Unfortunately, metalation trials of these biopolymeric Schiff bases afford the corresponding Ag(I)/M(II) complexes (where M=Co, Pd). These designed architectures were structurally characterized and pharmacologically evaluated for their in vitro antimicrobial, against common bacterial and fungal pathogens, and anticancer activities against human colon carcinoma (HCT-116) cell line. In conclusion functionalization of chitosan with IL-Sal brushes coupled with metalation of formed ILCSBs were synergistically enhanced its antimicrobial and antitumor properties to a great extent. Noteworthy, Ag-ILCSB2 (IC50=9.13μg/mL) was ca. 5-fold more cytotoxic against HCT-116 cell line than ILCSB2 (IC50=43.30μg/mL).

  12. Electrospun chitosan-graft-poly (ε -caprolactone)/poly (ε-caprolactone) cationic nanofibrous mats as potential scaffolds for skin tissue engineering.

    PubMed

    Chen, Honglin; Huang, Jin; Yu, Jiahui; Liu, Shiyuan; Gu, Ping

    2011-01-01

    This research is aimed to develop cationic nanofibrous mats with improved cellular adhesion profiles and stability of three-dimensional fibrous structure as potential scaffolds for skin tissue engineering. Firstly, amino-remained chitosan-graft-poly (ɛ-caprolactone) (CS-g-PCL) was synthesized with a facile one-step manner by grafting ɛ-caprolactone oligomers onto the hydroxyl groups of CS via ring-opening polymerization by using methanesulfonic acid as solvent and catalyst. And then, CS-g-PCL/PCL nanofibrous mats were obtained by electrospinning of CS-g-PCL/PCL mixed solution. Scanning electron microscopy (SEM) images showed that the morphologies and diameters of the nanofibers were mainly affected by the weight ratio of CS-g-PCL to PCL. The enrichment of amino groups on the nanofiber surface was confirmed by X-ray photoelectron spectroscopy (XPS). With the increase of CS-g-PCL in CS-g-PCL/PCL nanofiber, the content of amino groups on the nanofiber surface increased, which resulted in the increase of zeta-potential of nanofibers. Studies on cell-scaffold interaction were carried out by culturing mouse fibroblast cells (L929) on CS-g-PCL/PCL nanofibrous mats with various contents of CS-g-PCL by assessing the growth, proliferation and morphologies of cells. The results of MTS assay and SEM observation showed that CS-g-PCL/PCL (2/8) mats with a moderate surface zeta-potential (ζ=3mV) were the best in promoting the cell attachment and proliferation. Toluidine blue staining further confirmed that L929 cells grew well and exhibited a normal morphology on the CS-g-PCL/PCL (2/8) mats. These results suggested the potential utilization of CS-g-PCL/PCL (2/8) nanofibrous mats for skin tissue engineering. Copyright © 2010 Elsevier B.V. All rights reserved.

  13. Suppression of the tert-butylhydroquinone toxicity by its grafting onto chitosan and further cross-linking to agavin toward a novel antioxidant and prebiotic material.

    PubMed

    Hernández-Valdepeña, Miguel A; Pedraza-Chaverri, José; Gracia-Mora, Isabel; Hernández-Castro, Rigoberto; Sánchez-Bartez, Francisco; Nieto-Sotelo, Jorge; Montiel, Carmina; Shirai, Keiko; Gimeno, Miquel

    2016-05-15

    The enzyme-mediated grafting of tert-butylhydroquinone (TBHQ) onto chitosan and further crosslinking to agave inulin (agavin) has been successfully achieved in a mild and non-toxic two-step route. The resulting products were characterized by nuclear magnetic resonance (NMR) and Infra-red spectroscopies to assess the molecular structure. The study of acute oral toxicity in mice revealed no adverse short-term effects of consumption in the synthesized materials with non-toxicity evidence until 2000 mg/kg through an oral acute administration. Importantly, this study proves that the compound maintains the radical scavenging capacity of the phenolic antioxidant upon ferric-reducing antioxidant power (FRAP) and oxygen radical absorbance capacity (ORAC) assays with a measured half-maximal inhibitory concentration (IC50) for the best case of 1.54 g/L based on inhibition of 2,2'-azino-bis(3-ethylbenzothiazoline)-6-sulfonic acid diammonium salt (ABTS). Additionally, the novel compound presented high prebiotic activities as ascertained in the presence of lactic acid bacteria (LAB). Copyright © 2015 Elsevier Ltd. All rights reserved.

  14. Effect of kojic acid-grafted-chitosan oligosaccharides as a novel antibacterial agent on cell membrane of gram-positive and gram-negative bacteria.

    PubMed

    Liu, Xiaoli; Xia, Wenshui; Jiang, Qixing; Xu, Yanshun; Yu, Peipei

    2015-09-01

    Our work here, for the first time, reported the antibacterial activity of kojic acid-grafted-chitosan oligosaccharides (COS/KA) against three gram-positive and three gram-negative bacteria. Integrity of cell membrane, outer membrane (OM) and inner membrane (IM) permeabilization assay, alkaline phosphatase (ALP) and glucose-6-phosphate dehydrogenase (G6PDH) assay, and SDS-PAGE assay techniques were used to investigate the interactions between COS/KA and bacterial membranes. The antibacterial activity of COS/KA was higher than those of unmodified COS. The electric conductivity of bacteria suspensions increased, followed by increasing of the units of average release for ALP and G6PDH. COS/KA can also rapidly increase the 1-N-phenylanphthylamine (NPN) uptake and the release of β-galactosidase via increasing the permeability of OM and IM in Escherichia coli. SDS-PAGE indicated the content of cellular soluble proteins decreased significantly in COS/KA-treated bacteria. Hence, COS/KA has potential in food industry and biomedical sciences.

  15. Thermo- and pH-sensitive ionic-crosslinked hollow spheres from chitosan-based graft copolymer for 5-fluorouracil release.

    PubMed

    Li, Guiying; Guo, Lei; Wen, Quanwu; Zhang, Ting

    2013-04-01

    Thermo- and pH-sensitive ionic-crosslinked hollow spheres from self-assembly of chitosan-graft-poly(N-isopropylacrylamide) (CS-g-PNIPAM) for controlled release of 5-fluorouracil were studied. CS-g-PNIPAM aggregated into core-shell micelles with collapsed PNIPAM as the core and CS as the shell at the temperature above LCST. Ionic crosslinking reagent sodium tripolyphosphate (TPP) was used to crosslink the shell to form hollow spheres after cooling to room temperature. The size of hollow spheres was manipulated by changing pH or temperature of the environment. The CS-g-PNIPAM hollow spheres with plenty of inner cavities showed high loading capacity for 5-fluorouracil due to the polymer-drug interactions. Release of 5-fluorouracil from nanoparticles was accelerated at the temperature above LCST ascribed to the destruction of polymer-drug interactions and the decrease of particles size. Changing pH or ionic strength deformed the structure hollow spheres, which led to the increase of drug release. These hollow nanoparticles with environmentally sensitive properties are expected to be utilized in the field of intelligent drug delivery. Copyright © 2013 Elsevier B.V. All rights reserved.

  16. A novel reusable nanocomposite adsorbent, xanthated Fe3O4-chitosan grafted onto graphene oxide, for removing Cu(II) from aqueous solutions

    NASA Astrophysics Data System (ADS)

    Liu, Jinshui; Liu, Wenxiu; Wang, Yiru; Xu, Meijiao; Wang, Bin

    2016-03-01

    Novel nanocomposites of xanthated Fe3O4-chitosan grafted onto graphene oxide (xanthated Fe3O4-CS-GO) were successfully synthesized for the first time using an amidation reaction. The xanthated Fe3O4-CS-GO was used to remove Cu(II) from aqueous solutions. The xanthated Fe3O4-CS-GO was characterized using scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray diffractometry, and energy dispersive X-ray spectroscopy. The Cu(II) adsorption isotherms for the xanthated Fe3O4-CS-GO fitted the Langmuir isotherm model. The maximum Cu(II) adsorption capacity of the xanthated Fe3O4-CS-GO was 426.8 mg g-1, which is much higher than the maximum adsorption capacities of other adsorbents that have been described in the literature. This was attributed to xanthated Fe3O4-CS-GO having abundant functional groups. The xanthated Fe3O4-CS-GO could be regenerated using ethylene diamine tetraacetic acid, and could easily be removed from a liquid using an external magnetic field. These features would allow secondary pollution of the environment to be avoided more easily than is the case for other adsorbents. Cu(II) was adsorbed from aqueous solutions quickly and efficiently by the xanthated Fe3O4-CS-GO complex, suggesting that xanthated Fe3O4-CS-GO may be an ideal candidate for removing Cu(II) from wastewater.

  17. Grafting of gallic acid onto chitosan nano particles enhances antioxidant activities in vitro and protects against ochratoxin A toxicity in catfish (Clarias gariepinus).

    PubMed

    Abdel-Wahhab, Mosaad A; Aljawish, Abdulhadi; Kenawy, Amany M; El-Nekeety, Aziza A; Hamed, Heba S; Abdel-Aziem, Sekena H

    2016-01-01

    This study aimed to prepare and characterize enzymatic modified chitosan nanoparticles (CSNPs) with gallic acid (GA) or octyl gallate (OG) to optimize its potential in human application and to evaluate their protective role against ochrtoxin A (OTA) toxicity in catfish. The modified CSNPs have average size around 90 nm with positive charge and high scavenging activity especially GA-CSNPs. In the in vivo study, catfish were divided into 8 groups and treated for 3 weeks as follow: the control group, OTA-treated group (1 mg/kg b.w.), the groups treated with CSNPs, GA-CSNPs or OG-CSNPs (280 mg/kg b.w.) anole or in combination with OTA. Blood, liver and kidney samples were collected for different analyses. OTA induced a significant biochemical disturbances accompanied with oxidative stress in liver and kidney, histological changes and increase DNA fragmentation in the kidney. Co-treatment with OTA plus the different CSNPs resulted in a significant improvement in all tested parameters and histological picture of the kidney. This improvement was more pronounced in the group treated with GA-CSNPs. It could be concluded that grafting of GA or its ester improved the properties of CSNPs. Moreover, GA-CSNPs showed strong scavenging properties than OG-CSNPs due to the blocking of carboxyl groups responsible of the scavenging activity in OG.

  18. Environmentally friendly chitosan/PEI-grafted magnetic gelatin for the highly effective removal of heavy metals from drinking water

    NASA Astrophysics Data System (ADS)

    Li, Bingbing; Zhou, Feng; Huang, Kai; Wang, Yipei; Mei, Surong; Zhou, Yikai; Jing, Tao

    2017-02-01

    The development of environmentally friendly sorbents with a high adsorption capacity is an essential problem in the removal of heavy metals from drinking water. In this study, magnetic gelatin was prepared using transglutaminase as a cross-linker, which could only catalyze an acyl-transfer reaction between lysine and glutamine residues of the gelatin and not affect other amino groups. Therefore, it was beneficial for the further modification based on the amino groups, and did not affect the spatial structure of gelatin, which can effectively prevent the embedding of active sites in the polymer matrix. After modification with the chitosan/polyethylenimine copolymers, the numbers of amino groups was greatly increased, and the magnetic composites exhibited a high adsorption capacity, excellent water compatibility and simple magnetic separation. The adsorption capacities of lead and cadmium were 341 mg g-1 and 321 mg g-1, respectively, which could be used for the removal of metal ions in drinking water.

  19. Environmentally friendly chitosan/PEI-grafted magnetic gelatin for the highly effective removal of heavy metals from drinking water.

    PubMed

    Li, Bingbing; Zhou, Feng; Huang, Kai; Wang, Yipei; Mei, Surong; Zhou, Yikai; Jing, Tao

    2017-02-22

    The development of environmentally friendly sorbents with a high adsorption capacity is an essential problem in the removal of heavy metals from drinking water. In this study, magnetic gelatin was prepared using transglutaminase as a cross-linker, which could only catalyze an acyl-transfer reaction between lysine and glutamine residues of the gelatin and not affect other amino groups. Therefore, it was beneficial for the further modification based on the amino groups, and did not affect the spatial structure of gelatin, which can effectively prevent the embedding of active sites in the polymer matrix. After modification with the chitosan/polyethylenimine copolymers, the numbers of amino groups was greatly increased, and the magnetic composites exhibited a high adsorption capacity, excellent water compatibility and simple magnetic separation. The adsorption capacities of lead and cadmium were 341 mg g(-1) and 321 mg g(-1), respectively, which could be used for the removal of metal ions in drinking water.

  20. Environmentally friendly chitosan/PEI-grafted magnetic gelatin for the highly effective removal of heavy metals from drinking water

    PubMed Central

    Li, Bingbing; Zhou, Feng; Huang, Kai; Wang, Yipei; Mei, Surong; Zhou, Yikai; Jing, Tao

    2017-01-01

    The development of environmentally friendly sorbents with a high adsorption capacity is an essential problem in the removal of heavy metals from drinking water. In this study, magnetic gelatin was prepared using transglutaminase as a cross-linker, which could only catalyze an acyl-transfer reaction between lysine and glutamine residues of the gelatin and not affect other amino groups. Therefore, it was beneficial for the further modification based on the amino groups, and did not affect the spatial structure of gelatin, which can effectively prevent the embedding of active sites in the polymer matrix. After modification with the chitosan/polyethylenimine copolymers, the numbers of amino groups was greatly increased, and the magnetic composites exhibited a high adsorption capacity, excellent water compatibility and simple magnetic separation. The adsorption capacities of lead and cadmium were 341 mg g−1 and 321 mg g−1, respectively, which could be used for the removal of metal ions in drinking water. PMID:28225082

  1. Design of novel sheet-shaped chitosan hydrogel for wound healing: a hybrid biomaterial consisting of both PEG-grafted chitosan and crosslinkable polymeric micelles acting as drug containers.

    PubMed

    Ito, Tomoki; Yoshida, Chikara; Murakami, Yoshihiko

    2013-10-01

    In this study, we successfully prepared a novel "sheet-shaped" chitosan hydrogel for wound healing consisting of both PEG-g-chitosan and a crosslinkable polymeric micelle. The study's findings clarify that the PEG modification percentage (PMP) of PEG-g-chitosan increased proportionally as the weight ratio of PEG/chitosan increased. Furthermore, the positive second virial coefficient of PEG-g-chitosans from a Debye plot strongly suggests that the PEG modification greatly improved the solubility of the water-insoluble chitosan. Finally, the "sheet-shaped" "flexible" hydrogel formed by mixing solutions containing either PEG-g-chitosan with moderate PMP or polymeric micelles exhibited the highest storage modulus. The sheet itself exhibited an attractive feature insofar as polymeric micelles, which can act as drug containers facilitating the incorporation and the gradual release of drugs, are covalently immobilized in the polymeric network of the hydrogel. The results obtained in the present study show that the hybrid PEG-g-chitosan hydrogel containing crosslinkable polymeric micelles has the potential to address the need for novel functional biomaterials. Copyright © 2013 Elsevier B.V. All rights reserved.

  2. Fibrous polymer-grafted chitosan/clay composite beads as a carrier for immobilization of papain and its usability for mercury elimination.

    PubMed

    Metin, Ayşegül Ülkü; Alver, Erol

    2016-07-01

    Papain, which is an industrially important enzyme, has been immobilized on fibrous polymer-modified composite beads, namely poly(methacrylic acid)-grafted chitosan/clay. Characterization studies have been done using FTIR and SEM analysis. Operating parameters such as pH and initial concentration of papain have been varied to obtain the finest papain immobilized polymer-modified composite beads. The immobilization capacity of composite beads has been determined as 34.47 ± 1.18 (n = 3) mg/g. The proteolytic activity of immobilized papain was operated using bovine serum albumin (BSA) and maximum velocity (V max) and Michaelis-Menten constant (Km) values of the free and immobilized enzymes were determined using Lineweaver-Burk and Eadie-Hofstee equations. Usability of papain immobilized polymer-modified composite beads as adsorbents for the elimination of mercury was investigated. The maximum removal capacity of PIPMC beads has been found to be 4.88 ± 0.21 mg Hg/g when the initial metal concentration and weight of polymer-modified composite beads were 50 mg/L and 0.04 g at pH 7, respectively. Mercury removal performance of the papain immobilized polymer-modified composite beads was investigated in conjunction with Cu (II), Zn (II) and Cd (II) ions. The mercury adsorption capacity of papain immobilized polymer-modified composite beads was a slight reduction from 1.15 to 0.89 mg/g in presence of multiple metal salts.

  3. Chitosan grafted methoxy poly(ethylene glycol)-poly(ε-caprolactone) nanosuspension for ocular delivery of hydrophobic diclofenac

    PubMed Central

    Shi, Shuai; Zhang, Zhaoliang; Luo, Zichao; Yu, Jing; Liang, Renlong; Li, Xingyi; Chen, Hao

    2015-01-01

    This study aimed to develop a cationic nanosuspension of chitosan (CS) and methoxy poly(ethylene glycol)-poly(ε-caprolactone) (MPEG-PCL) for ocular delivery of diclofenac (DIC). MPEG-PCL-CS block polymer was synthesized by covalent coupling of MPEG-PCL with CS. The critical micelle concentration of the MPEG-PCL-CS block polymer was 0.000692 g/L. DIC/MPEG-PCL-CS nanosuspension (mean particle size = 105 nm, zeta potential = 8 mV) was prepared and characterized by Fourier transform infrared spectroscopy, X-ray diffraction, and differential scanning calorimetry. The nanosuspension was very stable without apparent physical property changes after storage at 4 °C or 25 °C for 20 days, but it was unstable in the aqueous humor solution after 24 h incubation. Sustained release of the encapsulated DIC from the nanosuspension occurred over 8 h. Neither a blank MPEG-PCL-CS nanosuspension nor a 0.1% (mass fraction) DIC/MPEG-PCL-CS nanosuspension caused ocular irritation after 24 h of instillation. Enhanced penetration and retention in corneal tissue was achieved with a Nile red/MPEG-PCL-CS nanosuspension compared with a Nile red aqueous solution. In vivo pharmacokinetics studies showed enhanced pre-corneal retention and penetration of the DIC/MPEG-PCL-CS nanosuspension, which resulted in a higher concentration of DIC (Cmax) in the aqueous humor and better bioavailability compared with commercial DIC eye drops (P < 0.01). PMID:26067670

  4. Chitosan grafted methoxy poly(ethylene glycol)-poly(ε-caprolactone) nanosuspension for ocular delivery of hydrophobic diclofenac.

    PubMed

    Shi, Shuai; Zhang, Zhaoliang; Luo, Zichao; Yu, Jing; Liang, Renlong; Li, Xingyi; Chen, Hao

    2015-06-12

    This study aimed to develop a cationic nanosuspension of chitosan (CS) and methoxy poly(ethylene glycol)-poly(ε-caprolactone) (MPEG-PCL) for ocular delivery of diclofenac (DIC). MPEG-PCL-CS block polymer was synthesized by covalent coupling of MPEG-PCL with CS. The critical micelle concentration of the MPEG-PCL-CS block polymer was 0.000692 g/L. DIC/MPEG-PCL-CS nanosuspension (mean particle size = 105 nm, zeta potential = 8 mV) was prepared and characterized by Fourier transform infrared spectroscopy, X-ray diffraction, and differential scanning calorimetry. The nanosuspension was very stable without apparent physical property changes after storage at 4 °C or 25 °C for 20 days, but it was unstable in the aqueous humor solution after 24 h incubation. Sustained release of the encapsulated DIC from the nanosuspension occurred over 8 h. Neither a blank MPEG-PCL-CS nanosuspension nor a 0.1% (mass fraction) DIC/MPEG-PCL-CS nanosuspension caused ocular irritation after 24 h of instillation. Enhanced penetration and retention in corneal tissue was achieved with a Nile red/MPEG-PCL-CS nanosuspension compared with a Nile red aqueous solution. In vivo pharmacokinetics studies showed enhanced pre-corneal retention and penetration of the DIC/MPEG-PCL-CS nanosuspension, which resulted in a higher concentration of DIC (Cmax) in the aqueous humor and better bioavailability compared with commercial DIC eye drops (P < 0.01).

  5. Functionalization of chitosan by a free radical reaction: Characterization, antioxidant and antibacterial potential.

    PubMed

    Moreno-Vásquez, María Jesús; Valenzuela-Buitimea, Emma Lucía; Plascencia-Jatomea, Maribel; Encinas-Encinas, José Carmelo; Rodríguez-Félix, Francisco; Sánchez-Valdes, Saúl; Rosas-Burgos, Ema Carina; Ocaño-Higuera, Víctor Manuel; Graciano-Verdugo, Abril Zoraida

    2017-01-02

    Chitosan was functionalized with epigallocatechin gallate (EGCG) by a free radical-induced grafting procedure, which was carried out by a redox pair (ascorbic acid/hydrogen peroxide) as the radical initiator. The successful preparation of EGCG grafted-chitosan was verified by spectroscopic (UV, FTIR and XPS) and thermal (DSC and TGA) analyses. The degree of grafting of phenolic compounds onto the chitosan was determined by the Folin-Ciocalteu procedure. Additionally, the biological activities (antioxidant and antibacterial) of pure EGCG, blank chitosan and EGCG grafted-chitosan were evaluated. The spectroscopic and thermal results indicate chitosan functionalization with EGCG; the EGCG content was 25.8mg/g of EGCG grafted-chitosan. The antibacterial activity of the EGCG grafted-chitosan was increased compared to pure EGCG or blank chitosan against S. aureus and Pseudomonas sp. (p<0.05). Additionally, EGCG grafted-chitosan showed higher antioxidant activity than blank chitosan. These results indicate that EGCG grafted-chitosan might be useful in active food packaging.

  6. Adsorption of fucoidan and chitosan sulfate on chitosan modified PET films monitored by QCM-D.

    PubMed

    Indest, Tea; Laine, Janne; Johansson, Leena-Sisko; Stana-Kleinschek, Karin; Strnad, Simona; Dworczak, Renate; Ribitsch, Volker

    2009-03-09

    The adsorption behavior of fucoidan as well as chitosan derivatives (chitosan sulfate) on poly(ethylene terephthalate) (PET) model film surface was studied using the quartz crystal microbalance technique. These systems were chosen for this study due to their promising biocompatible properties. Moreover, fucoidan and chitosan sulfate have promising anticoagulant properties and represent an alternative to heparin treatment of vascular grafts. As a first step, PET foils were activated by alkaline hydrolysis to increase their hydrophilicity. From these foils, model PET films were prepared by the spin coating technique on a silica quartz crystal. The selected polysaccharides (chitosan, fucoidan, and chitosan sulfate) were adsorbed from aqueous solutions on the PET surfaces. The adsorption was monitored using a quartz crystal microbalance with a dissipation unit. The surface chemistry and morphology of the chitosan/fucoidan or chitosan/chitosan sulfate coated PET-H films was analyzed using XPS and AFM. It was found that chitosan/fucoidan films were thinner and more compressed, while in the case of chitosan/chitosan sulfate, large amounts of chitosan sulfate were adsorbed, indicating a loose and thick adsorbed film.

  7. Polymethylmethacrylate membrane with a series of serendipity.

    PubMed

    Sakai, Yoshitada

    2011-01-01

    Forty years have passed since the polymethylmethacrylate (PMMA) membrane was first developed. This article reviews its history and explains its longevity. The membrane was developed through application of a stereocomplex phenomenon that is observed upon mixture of isotactic and syndiotactic PMMA polymers. Filtryzer(TM) B1 and B2 were approved in Japan in 1977. B1 was the pioneer high-performance membrane model and B2 was a model that simulated a low-flux cellulosic membrane. The development of B1 led to the development of the dialysis machine with an ultrafiltration rate (UFR)-controlling function because the UFR of B1 was too high to control using transmembrane pressure control. B1 was used not only as a dialyzer but also as a hemodiafilter by combination with a UFR controller. Biocompatibility of the dialysis membrane, complement activation and/or transient leukopenia was studied with B2. Cooperative studies between Niigata University and Toray resulted in Gejyo's finding regarding the harmfulness of β(2)-microglobulin (BMG). Long-term follow-up of patients dialyzed using the BK membrane revealed that plasma BMG levels were significantly low and that the occurrence ratio of carpal tunnel syndrome was suppressed. These results were obtained by the adsorptive removal of BMG onto a PMMA membrane. Several papers have discussed new aspects in succession mainly based on clinical experiences that were not aimed at a development stage, i.e. they were kinds of serendipity. For the BK-F membrane with the largest pore size, this includes anemia and removal or modification of furancarboxylic acid, homocysteine, pentosidine and soluble CD40. For the BG membrane with a slightly anionic component, this includes pruritus and removal of free immunoglobulin light chains. Even patients' prognoses may be modified by the use of PMMA membrane. The mechanisms of these findings have been clarified bit by bit and the membrane will further open new frontiers in dialysis treatment.

  8. The interplay between nanostructured carbon-grafted chitosan scaffolds and protein adsorption on the cellular response of osteoblasts: structure-function property relationship.

    PubMed

    Depan, D; Misra, R D K

    2013-04-01

    The rapid adsorption of proteins occurs during the early stages of biomedical device implantation into physiological systems. In this regard, the adsorption of proteins is a strong function of the nature of a biomedical device, which ultimately governs the biological functions. The objective of this study was to elucidate the interplay between nanostructured carbon-modified (graphene oxide and single-walled carbon nanohorn) chitosan scaffolds and consequent protein adsorption and biological function (osteoblast function). We compare and contrast the footprint of protein adsorption on unmodified chitosan and nanostructured carbon-modified chitosan. A comparative analysis of cell-substrate interactions using an osteoblast cell line (MC3T3-E1) implied that biological functions were significantly enhanced in the presence of nanostructured carbon, compared with unmodified chitosan. The difference in their respective behaviors is related to the degree and topography of protein adsorption on the scaffolds. Furthermore, there was a synergistic effect of nanostructured carbon and protein adsorption in terms of favorably modulating biological functions, including cell attachment, proliferation and viability, with the effect being greater on nanostructured carbon-modified scaffolds. The study also underscores that protein adsorption is favored in nanostructured carbon-modified scaffolds such that bioactivity and biological function are promoted.

  9. Fabrication and characterization of heparin-grafted poly-L-lactic acid-chitosan core-shell nanofibers scaffold for vascular gasket.

    PubMed

    Wang, Ting; Ji, Xuyuan; Jin, Lin; Feng, Zhangqi; Wu, Jinghang; Zheng, Jie; Wang, Hongyin; Xu, Zhe-Wu; Guo, Lingling; He, Nongyue

    2013-05-01

    Electrospun nanofibers were widely studied to be applied as potential materials for tissue engineering. A new technology to make poly-l-lactic acid/chitosan core/shell nanofibers from heterologous solution by coaxial electrospinning technique was designed for vascular gasket. Chitosan surface was cross-linked by genipin and modified by heparin. Different ratios of PLA/CS in heterologous solution were studied to optimize the surface morphology of fibers. Clean core-shell structures formed with a PLA/CS ratio at 1:3. Superior biocompatibility and mechanical properties were obtained by optimizing the core-shell structure morphology and surface cross-linking of chitosan. UE7T-13 cells grew well on the core-shell structure fibers as indicated by methylthiazolyldiphenyl-tetrazolium bromide (MTT) results and scanning electron microscopy (SEM) images. Compared with the pure PLA fiber meshes and commercial vascular patch, PLA/CS core-shell fibers had better mechanical strength. The elastic modulus was as high as 117.18 MPa, even though the yield stress of the fibers was lower than that of the commercial vascular patch. Attachment of red blood cell on the fibers was evaluated by blood anticoagulation experiments and in vitro blood flow experiments. The activated partial thromboplastin time (APTT) and prothrombin time (PT) value from PLA/CS nanofibers were significantly longer than that of pure PLA fibers. SEM images indicated there were hardly any red blood cells attached to the fibers with chitosan coating and heparin modification. This type of fiber mesh could potentially be used as vascular gasket.

  10. Radiation grafting on natural films

    NASA Astrophysics Data System (ADS)

    Lacroix, M.; Khan, R.; Senna, M.; Sharmin, N.; Salmieri, S.; Safrany, A.

    2014-01-01

    Different methods of polymer grafting using gamma irradiation are reported in the present study for the preparation of newly functionalized biodegradable films, and some important properties related to their mechanical and barrier properties are described. Biodegradable films composed of zein and poly(vinyl alcohol) (PVA) were gamma-irradiated in presence of different ratios of acrylic acid (AAc) monomer for compatibilization purpose. Resulting grafted films (zein/PVA-g-AAc) had their puncture strength (PS=37-40 N mm-1) and puncture deformation (PD=6.5-9.8 mm) improved for 30% and 50% PVA in blend, with 5% AAc under 20 kGy. Methylcellulose (MC)-based films were irradiated in the presence of 2-hydroxyethyl methacrylate (HEMA) or silane, in order to determine the effect of monomer grafting on the mechanical properties of films. It was found that grafted films (MC-g-HEMA and MC-g-silane) using 35% monomer performed higher mechanical properties with PS values of 282-296 N mm-1 and PD of 5.0-5.5 mm under 10 kGy. Compatibilized polycaprolactone (PCL)/chitosan composites were developed via grafting silane in chitosan films. Resulting trilayer grafted composite film (PCL/chitosan-g-silane/PCL) presented superior tensile strength (TS=22 MPa) via possible improvement of interfacial adhesion (PCL/chitosan) when using 25% silane under 10 kGy. Finally, MC-based films containing crystalline nanocellulose (CNC) as a filling agent were prepared and irradiated in presence of trimethylolpropane trimethacrylate (TMPTMA) as a grafted plasticizer. Grafted films (MC-g-TMPTMA) presented superior mechanical properties with a TS of 47.9 MPa and a tensile modulus (TM) of 1792 MPa, possibly due to high yield formation of radicals to promote TMPTMA grafting during irradiation. The addition of CNC led to an additional improvement of the barrier properties, with a significant 25% reduction of water vapor permeability (WVP) of grafted films.

  11. Zero-order controlled release of BMP2-derived peptide P24 from the chitosan scaffold by chemical grafting modification technique for promotion of osteogenesis in vitro and enhancement of bone repair in vivo

    PubMed Central

    Chen, Yan; Liu, Xujie; Liu, Rui; Gong, Yong; Wang, Mingbo; Huang, Qianli; Feng, Qingling; Yu, Bo

    2017-01-01

    Combination of tissue-engineered bone scaffolds with cell-adhesive, osteoconductive, or osteoinductive biomolecules is a critical strategy to improve their properties that significantly influence cellular behaviors, such as adhesion, proliferation, and differentiation, which is beneficial for critical-sized bone defects repairing. However, the traditional surface modification techniques, such as physical adsorption, coating, and plasma treatment, et al, have great limitations for immobilization of bioactive molecules due to undesirable controlled delivery performance or overly complex multistep procedures. In this study, we functionalized the chitosan/hydroxyapatite (CS/HA) biomimetic composite scaffold for controlled delivery of BMP2-derived peptide (P24) by the chemical grafting modification technique: firstly, P24 was conjugated with a thiolated chitosan, chitosan-4-thiobutylamidine (CS-TBA); secondly, the resultant CS-P24 was then combined with HA to prepare CS-P24/HA scaffolds. The effect of CS-P24/HA scaffolds on bone regeneration was evaluated, along with the underlying biological mechanisms responsible in vitro and in vivo. In vitro, the controlled and sustained release of bioactive P24 could last up to 90 days, furthermore, the release profiles of CS-5%P24/HA and CS-10%P24/HA were linear and could be fitted according to zero-order kinetic model (R2=0.9929; R2=0.9757); P24 on the scaffold significantly promoted cell adhesion, proliferation, osteodifferentiation, and mineralization with synergistic effects. Bone marrow stromal cells (BMSCs) revealed spindle-shaped surface morphology, indicating the CS-P24/HA scaffolds supported cell adhesion and possessed a high proliferation rate that varied according to the P24 concentration levels. Furthermore, mRNA levels for OCN, Runx2, and collagen I were significantly up-regulated on CS-P24/HA scaffolds compared with cells grown on CS/HA scaffolds in vitro (p < 0.05). Similarly, the BMSCs exhibited a higher ALP

  12. Complexes of silver(I) ions and silver phosphate nanoparticles with hyaluronic acid and/or chitosan as promising antimicrobial agents for vascular grafts.

    PubMed

    Chudobova, Dagmar; Nejdl, Lukas; Gumulec, Jaromir; Krystofova, Olga; Rodrigo, Miguel Angel Merlos; Kynicky, Jindrich; Ruttkay-Nedecky, Branislav; Kopel, Pavel; Babula, Petr; Adam, Vojtech; Kizek, Rene

    2013-06-28

    Polymers are currently widely used to replace a variety of natural materials with respect to their favourable physical and chemical properties, and due to their economic advantage. One of the most important branches of application of polymers is the production of different products for medical use. In this case, it is necessary to face a significant disadvantage of polymer products due to possible and very common colonization of the surface by various microorganisms that can pose a potential danger to the patient. One of the possible solutions is to prepare polymer with antibacterial/antimicrobial properties that is resistant to bacterial colonization. The aim of this study was to contribute to the development of antimicrobial polymeric material ideal for covering vascular implants with subsequent use in transplant surgery. Therefore, the complexes of polymeric substances (hyaluronic acid and chitosan) with silver nitrate or silver phosphate nanoparticles were created, and their effects on gram-positive bacterial culture of Staphylococcus aureus were monitored. Stages of formation of complexes of silver nitrate and silver phosphate nanoparticles with polymeric compounds were characterized using electrochemical and spectrophotometric methods. Furthermore, the antimicrobial activity of complexes was determined using the methods of determination of growth curves and zones of inhibition. The results of this study revealed that the complex of chitosan, with silver phosphate nanoparticles, was the most suitable in order to have an antibacterial effect on bacterial culture of Staphylococcus aureus. Formation of this complex was under way at low concentrations of chitosan. The results of electrochemical determination corresponded with the results of spectrophotometric methods and verified good interaction and formation of the complex. The complex has an outstanding antibacterial effect and this effect was of several orders higher compared to other investigated complexes.

  13. Complexes of Silver(I) Ions and Silver Phosphate Nanoparticles with Hyaluronic Acid and/or Chitosan as Promising Antimicrobial Agents for Vascular Grafts

    PubMed Central

    Chudobova, Dagmar; Nejdl, Lukas; Gumulec, Jaromir; Krystofova, Olga; Rodrigo, Miguel Angel Merlos; Kynicky, Jindrich; Ruttkay-Nedecky, Branislav; Kopel, Pavel; Babula, Petr; Adam, Vojtech; Kizek, Rene

    2013-01-01

    Polymers are currently widely used to replace a variety of natural materials with respect to their favourable physical and chemical properties, and due to their economic advantage. One of the most important branches of application of polymers is the production of different products for medical use. In this case, it is necessary to face a significant disadvantage of polymer products due to possible and very common colonization of the surface by various microorganisms that can pose a potential danger to the patient. One of the possible solutions is to prepare polymer with antibacterial/antimicrobial properties that is resistant to bacterial colonization. The aim of this study was to contribute to the development of antimicrobial polymeric material ideal for covering vascular implants with subsequent use in transplant surgery. Therefore, the complexes of polymeric substances (hyaluronic acid and chitosan) with silver nitrate or silver phosphate nanoparticles were created, and their effects on gram-positive bacterial culture of Staphylococcus aureus were monitored. Stages of formation of complexes of silver nitrate and silver phosphate nanoparticles with polymeric compounds were characterized using electrochemical and spectrophotometric methods. Furthermore, the antimicrobial activity of complexes was determined using the methods of determination of growth curves and zones of inhibition. The results of this study revealed that the complex of chitosan, with silver phosphate nanoparticles, was the most suitable in order to have an antibacterial effect on bacterial culture of Staphylococcus aureus. Formation of this complex was under way at low concentrations of chitosan. The results of electrochemical determination corresponded with the results of spectrophotometric methods and verified good interaction and formation of the complex. The complex has an outstanding antibacterial effect and this effect was of several orders higher compared to other investigated complexes

  14. Polymethylmethacrylate imbedded with antibiotics cranioplasty: An infection solution for moderate and large defects reconstruction?

    PubMed Central

    Worm, Paulo Valdeci; do Nascimento, Tobias Ludwig; do Couto Nicola, Fabricio; Sanches, Eduardo Farias; dos Santos Moreira, Carlos Fernando; Rogério, Luiz Pedro Willimann; dos Reis, Marcelo Martins; Finger, Guilherme; Collares, Marcus Vinicius Martins

    2016-01-01

    Background: In cases where autologous bone graft reconstruction is not possible (such as comminuted fractures, bone graft reabsorption, or infection) and the use of synthetic material is required, polymethylmethacrylate (PMMA) use is a safe and efficient solution. Studies comparing the incidence of postoperative complications between autologous and synthetic cranioplasty are heterogeneous, not allowing a conclusion of which is the best material for skull defects reconstruction. Current medical literature lacks prospective well-delineated studies with long-term follow-up that analyze the impact of antibiotic use in PMMA cranial reconstruction of moderate and large defects. Methods: A prospective series of patients, who underwent cranioplasty reconstruction with PMMA impregnated with antibiotic, were followed for 2 years. Authors collected data regarding demographic status, clinical conditions, surgical information, and its complications. Results: A total of 58 patients completed full follow-up with a mean group age of 40 years and a male predominance (77%). Major complications that required surgical management were identified in 5 patients, and 10 patients evolved with minor complications. Postoperative surgical site infection incidence was 3.2%. Conclusion: The infection rate in patients submitted to PMMA flap cranioplasty impregnated with antibiotic is significantly inferior comparing to the data described in medical literature. A lower infection incidence impacts secondary endpoints such as minimizing surgical morbidity, mortality, hospitalization period, and, consequently, costs. PMID:27904754

  15. Recent progress on synthesis, property and application of modified chitosan: An overview.

    PubMed

    Wang, Junhua; Wang, Li; Yu, Haojie; Zain-Ul-Abdin; Chen, Yongsheng; Chen, Qing; Zhou, Weidong; Zhang, Hongtao; Chen, Xiao

    2016-07-01

    Because of the unique chemical structure, chitosan and its derivatives have been paid close extensive attention as the potential bio-functional material. This review presents recent synthesis of modified chitosan via N-substitution, O-substitution, free radical graft copolymerization and other modification methods and properties of the modified chitosan. The applications of the modified chitosan in metal ions adsorption, dye removal and pharmaceutical fields are illustrated as well. The rapid development in the modification of chitosan describes broad perspectives of the modified chitosan.

  16. Enzymatic modification of chitosan with quercetin and its application as antioxidant edible films.

    PubMed

    Torres, E; Marín, V; Aburto, J; Beltrán, H I; Shirai, K; Villanueva, S; Sandoval, G

    2012-01-01

    Quercetin, rutin, naringin, hesperidin and chrysin were tested as substrates for chloroperoxidase to produce reactive quinones to graft onto chitosan. Quercetin and rutin quinones were successfully chemically attached to low molecular weight chitosan. The quercetin-modified chitosan showed an enhancement of plastic, antioxidant and antimicrobial properties as well as of thermal degradability. Finally, chitosan-quercetin films visibly decreased enzymatic oxidation when applied to Opuntia ficus indica cladodes.

  17. A novel hierarchical nanobiocomposite of graphene oxide-magnetic chitosan grafted with mercapto as a solid phase extraction sorbent for the determination of mercury ions in environmental water samples.

    PubMed

    Ziaei, Ehsan; Mehdinia, Ali; Jabbari, Ali

    2014-11-19

    New mercapto-grafted graphene oxide-magnetic chitosan (GO-MC) has been developed as a novel biosorbent for the preconcentration and extraction of mercury ion from water samples. A facile and ecofriendly synthesis procedure was also developed for modification of GO-MC with 3-mercaptopropyltrimethoxysilane. The prepared nanocomposite material (mercapto/GO-MC) was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR) and energy-dispersive X-ray spectroscopy (EDX). The mercury analysis was performed by continuous-flow cold vapor atomic absorption spectrometry. The parameters affecting the extraction and preconcentration processes were carried out. The optimum conditions were found to be 60mg of sorbent, pH of 6.5, 10min for adsorption time, 3mL of HCl (0.1mol L(-1))/thiourea (2% w/v) as the eluent and 250mL for breakthrough volume. An excellent linearity was achieved in the range of 0.12-80ng mL(-1) (R(2)=0.999) at a preconcentration factor of 80. The limit of detection and quantification were achieved as 0.06ng mL(-1) and 0.12ng mL(-1), respectively. A good repeatability was obtained with the relative standard deviation (RSD) of 4.7%. Furthermore, real water samples were analyzed and good recoveries were obtained from 95 to 100%. Copyright © 2014 Elsevier B.V. All rights reserved.

  18. New application of Chitosan-grafted Polyaniline in dispersive solid-phase extraction for the separation and determination of phthalate esters in milk using high-performance liquid chromatography.

    PubMed

    Razavi, Nourolhoda; Yazdi, Ali Sarafraz

    2017-02-22

    Chitosan-grafted polyaniline was synthesized and applied as a sorbent for the preconcentration of phthalate esters in dispersive solid-phase extraction. By coupling dispersive solid-phase extraction with high-performance liquid chromatography and response surface methodology (central composite design), a reliable, sensitive and cost-effective method for simultaneous determination of phthalate esters including dimethyl phthalate, di-n-butyl phthalate, and di(2-ethylhexyl)phthalate was developed. The morphology of sorbent had been studied by scanning electron microscopy and its chemical structure confirmed by Fourier transform infrared spectroscopy. Under optimum condition, good linearity was observed in the range of 5.0-5000.0 ngmL(-1) . The limits of detection (S/N = 3) and limits of quantification (S/N = 10) were 0.1-0.3 and 0.3-1 ng mL(-1) , respectively. The relative standard deviations were less than 8.8%. Finally, this procedure was employed for extraction of trace amounts of phthalic acid esters in milk samples, the relative recoveries ranged from 82 to 103 %. This article is protected by copyright. All rights reserved.

  19. Evaluation of the potential of chitosan/β-1,3-glucan/hydroxyapatite material as a scaffold for living bone graft production in vitro by comparison of ADSC and BMDSC behaviour on its surface.

    PubMed

    Przekora, Agata; Vandrovcova, Marta; Travnickova, Martina; Pajorova, Julia; Molitor, Martin; Ginalska, Grazyna; Bacakova, Lucie

    2017-02-24

    The opinion regarding the origin of adult stem cells that should be used for living bone construct generation is strongly divided in the scientific community. In this study, the potential of chitosan/β-1,3-glucan/hydroxyapatite (chit/glu/HA) material as a scaffold for bone regeneration applications was evaluated by behaviour comparison of adult stem cells derived from both origins-adipose derived mesenchymal stem cell (ADSC) tissue and bone marrow derived mesenchymal stem cells (BMDSCs). In the case of ADSC isolation, low and high negative pressures were applied during a liposuction procedure in order to determine if negative pressure settings may have an impact on subsequent cell behaviour in vitro. The obtained results demonstrated that the chit/glu/HA material is a promising candidate to be used for living bone graft production in vitro as both ADSCs and BMDSCs revealed a satisfactory proliferation and differentiation ability on its surface. Nevertheless, BMDSCs would be a better choice of adult stem cells since they were better spread, more strongly attached and showed a more superior proliferation and differentiation ability than ADSCs when cultured on the chit/glu/HA scaffold. However, if BMDSCs cannot be isolated, ADSCs may be used for bone construct production but lipoaspirate should be collected under low negative pressure (-200 mm Hg), as high negative pressure (-700 mmHg) applied during liposuction surgery may retard subsequent ADSC proliferation and type I collagen production.

  20. Electrochemical imprinted sensor for determination of oleanic acid based on poly (sodium 4-styrenesulfonate-co-acrylic acid)-grafted multi-walled carbon nanotubes-chitosan and cobalt hexacyanoferrate nanoparticles.

    PubMed

    Hu, Yufang; Zhang, Zhaohui; Li, Jiaxing; Zhang, Huabin; Luo, Lijuan; Yao, Shouzhuo

    2012-01-15

    A novel sensitive and selective imprinted electrochemical sensor for the determination of oleanic acid was constructed on a carbon electrode by stepwise modification of functional multi-walled carbon nanotubes, cobalt hexacyanoferrate nanoparticles and a thin imprinted sol-gel film. The fabrication of a homogeneous porous poly (sodium 4-styrenesulfonate-co-acrylic acid)-grafted multi-walled carbon nanotubes/SiO(2)-chitosan nanocomposite film was conducted by controllable electrodeposition technology. The surface morphologies of the modified electrodes were characterized by scanning electron microscope. The performance of the imprinted sensor was investigated by cyclic voltammetry, square wave voltammetry and electrochemical impedance spectroscopy in detail. The imprinted sensor displayed high sensitivity and selectivity towards oleanic acid. A linear relationship between the sensor response signal and the logarithm of oleanic acid concentrations ranging from 1.0×10(-8) to 1.0×10(-3) mol L(-1) was obtained with a detection limit of 2.0×10(-9) mol L(-1). It was applied to the determination of oleanic acid in real capsule samples successfully. Copyright © 2011 Elsevier B.V. All rights reserved.

  1. Chitosan-amylopectin/hydroxyapatite and chitosan-chondroitin sulphate/hydroxyapatite composite scaffolds for bone tissue engineering.

    PubMed

    Venkatesan, Jayachandran; Pallela, Ramjee; Bhatnagar, Ira; Kim, Se-Kwon

    2012-12-01

    Over the past few decades, artificial graft materials for bone tissue engineering are gaining much importance. In this study, tri-component scaffolds of chitosan/natural hydroxyapatite with chondroitin sulfate (chitosan-CS/HAp) and amylopectin (chitosan-AP/HAp) have been developed for the first time via freeze-drying method and were characterized physicochemically for bone grafting substitutes. Chemical interactions and dispersion of HAp, CS and AP in the chitosan matrix have been evaluated by various analytical techniques. The porosity and water uptake/retention ability of these composite scaffolds decreased whereas thermal stability increased when compared to the chitosan scaffold. The pore size of the chitosan/HAp, chitosan-CS/HAp and chitosan-AP/HAp scaffolds varied from 60 to 180 μm, 60 to 400 μm and 80 to 500 μm, respectively. Cell proliferation, alkaline phosphatase activity and type-1 collagen production was evaluated in vitro using MG-63 cell line, which was observed to be higher in the composite scaffolds. Excellent interconnected porosity, controlled biodegradation and enhanced cell proliferation of the novel chitosan-CS/HAp and chitosan-AP/HAp scaffolds suggests that these scaffolds are promising biomaterials for bone tissue engineering. Copyright © 2012 Elsevier B.V. All rights reserved.

  2. Coaxial electrospinning multicomponent functional controlled-release vascular graft: Optimization of graft properties.

    PubMed

    Yin, Anlin; Luo, Rifang; Li, Jiukai; Mo, Xiumei; Wang, Yunbing; Zhang, Xingdong

    2017-04-01

    Small diameter vascular grafts possessing desirable biocompatibility and suitable mechanical properties have become an urgent clinic demand. Herein, heparin loaded fibrous grafts of collagen/chitosan/poly(l-lactic acid-co-ε-caprolactone) (PLCL) were successfully fabricated via coaxial electrospinning. By controlling the concentration of heparin and the ratio of collagen/chitosan/PLCL, most grafts had the heparin encapsulation efficiency higher than 70%, and the heparin presented sustained release for more than 45 days. Particularly, such multicomponent grafts had relative low initial burst release, and after heparin releasing for 3 weeks, the grafts still showed good anti-platelet adhesion ability. In addition, along with the excellent cell biocompatibility, the fabricated grafts possessed suitable mechanical properties including good tensile strength, suture retention strength, burst pressure and compliance which could well match the native blood vessels. Thus, the optimized graft properties could be properly addressed for vascular tissue application via coaxial electrospinning. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Galactosylated chitosan-grafted multiwall carbon nanotubes for pH-dependent sustained release and hepatic tumor-targeted delivery of doxorubicin in vivo.

    PubMed

    Qi, Xiaole; Rui, Yao; Fan, Yuchao; Chen, Haiyan; Ma, Ning; Wu, Zhenghong

    2015-09-01

    Carbon nanotubes (CNTs) are well known for their distinctive drug-loading ability that is mainly due to their large surface area, which permits covalent attachment of various target ligands or drug molecules by π-π stacking, allowing them to act as potential tumor-targeting carriers. Herein, we describe the development of galactosylated chitosan-graftedoxidized CNTs (O-CNTs-LCH) for pH-dependent sustained release and hepatic tumor-targeted delivery of doxorubicin (DOX). The in vitro release behavior in aqueous release media of different pH values (5.5, 6.5 and 7.4) verified the pH-dependent sustained release of DOX from O-CNTs-LCH-DOX. Moreover, these nanocarriers exhibited significant in vitro tumor-targeting properties, with a higher cellular uptake efficiency than that of free DOX in HepG2 cells. In addition, the good biocompatibility and low toxicity of O-CNTs-LCH-DOX was demonstrated by evaluating HepG2 cytotoxicity, vascular irritation and the maximum tolerated dose. Moreover, after intravenous administration in mice bearing the H22 tumor, O-CNTs-LCH-DOX showed higher antitumor activity and stronger fluorescent intensity in tumor tissue compared to free DOX. These results indicated the selective hepatic tumor targeting and the therapeutic effect of those nanocarriers.

  4. Development of chitosan graft pluronic®F127 copolymer nanoparticles containing DNA aptamer for paclitaxel delivery to treat breast cancer cells

    NASA Astrophysics Data System (ADS)

    Thach Nguyen, Kim; Le, Duc Vinh; Do, Dinh Ho; Huan Le, Quang

    2016-06-01

    HER-2/ErbB2/Neu(HER-2), a member of the epidermal growth factor receptor family, is specifically overexpressed on the surface of breast cancer cells and serves a therapeutic target for breast cancer. In this study, we aimed to isolate DNA aptamer (Ap) that specifically bind to a HER-2 overexpressing SK-BR-3 human breast cancer cell line, using SELEX strategy. We developed a novel multifunctional composite micelle with surface modification of Ap for targeted delivery of paclitaxel. This binary mixed system consisting of Ap modified pluronic®F127 and chitosan could enhance PTX loading capacity and increase micelle stability. Polymeric micelles had a spherical shape and were self-assemblies of block copolymers of approximately 86.22 ± 1.45 nm diameter. PTX could be loaded with high encapsulation efficiency (83.28 ± 0.13%) and loading capacity (9.12 ± 0.34%). The release profile were 29%-35% in the first 12 h and 85%-93% after 12 d at pH 7.5 of receiving media. The IC50 doses by MTT assay showed the greater activity of nanoparticles loaded paclitaxel over free paclitaxel and killed cells up to 95% after 6 h. These results demonstrated unique assembly with the capacity to function as an efficient detection and delivery vehicle in the biological living system.

  5. Patient-Derived Human Induced Pluripotent Stem Cells From Gingival Fibroblasts Composited With Defined Nanohydroxyapatite/Chitosan/Gelatin Porous Scaffolds as Potential Bone Graft Substitutes

    PubMed Central

    Ji, Jun; Tong, Xin; Huang, Xiaofeng; Zhang, Junfeng

    2016-01-01

    Human embryonic stem cells and adult stem cells have always been the cell source for bone tissue engineering. However, their limitations are obvious, including ethical concerns and/or a short lifespan. The use of human induced pluripotent stem cells (hiPSCs) could avoid these problems. Nanohydroxyapatite (nHA) is an important component of natural bone and bone tissue engineering scaffolds. However, its regulation on osteogenic differentiation with hiPSCs from human gingival fibroblasts (hGFs) is unknown. The purpose of the present study was to investigate the osteogenic differentiation of hiPSCs from patient-derived hGFs regulated by nHA/chitosan/gelatin (HCG) scaffolds with different nHA ratios, such as HCG-111 (1 wt/vol% nHA) and HCG-311 (3 wt/vol% nHA). First, hGFs were reprogrammed into hiPSCs, which have enhanced osteogenic differentiation capability. Second, HCG-111 and HCG-311 scaffolds were successfully synthesized. Finally, hiPSC/HCG complexes were cultured in vitro or subcutaneously transplanted into immunocompromised mice in vivo. The osteogenic differentiation effects of two types of HCG scaffolds on hiPSCs were assessed for up to 12 weeks. The results showed that HCG-311 increased osteogenic-related gene expression of hiPSCs in vitro proved by quantitative real-time polymerase chain reaction, and hiPSC/HCG-311 complexes formed much bone-like tissue in vivo, indicated by cone-beam computed tomography imaging, H&E staining, Masson staining, and RUNX-2, OCN immunohistochemistry staining. In conclusion, our study has shown that osteogenic differentiation of hiPSCs from hGFs was improved by HCG-311. The mechanism might be that the nHA addition stimulates osteogenic marker expression of hiPSCs from hGFs. Our work has provided an innovative autologous cell-based bone tissue engineering approach with soft tissues such as clinically abundant gingiva. Significance The present study focused on patient-personalized bone tissue engineering. Human induced

  6. Patient-Derived Human Induced Pluripotent Stem Cells From Gingival Fibroblasts Composited With Defined Nanohydroxyapatite/Chitosan/Gelatin Porous Scaffolds as Potential Bone Graft Substitutes.

    PubMed

    Ji, Jun; Tong, Xin; Huang, Xiaofeng; Zhang, Junfeng; Qin, Haiyan; Hu, Qingang

    2016-01-01

    Human embryonic stem cells and adult stem cells have always been the cell source for bone tissue engineering. However, their limitations are obvious, including ethical concerns and/or a short lifespan. The use of human induced pluripotent stem cells (hiPSCs) could avoid these problems. Nanohydroxyapatite (nHA) is an important component of natural bone and bone tissue engineering scaffolds. However, its regulation on osteogenic differentiation with hiPSCs from human gingival fibroblasts (hGFs) is unknown. The purpose of the present study was to investigate the osteogenic differentiation of hiPSCs from patient-derived hGFs regulated by nHA/chitosan/gelatin (HCG) scaffolds with different nHA ratios, such as HCG-111 (1 wt/vol% nHA) and HCG-311 (3 wt/vol% nHA). First, hGFs were reprogrammed into hiPSCs, which have enhanced osteogenic differentiation capability. Second, HCG-111 and HCG-311 scaffolds were successfully synthesized. Finally, hiPSC/HCG complexes were cultured in vitro or subcutaneously transplanted into immunocompromised mice in vivo. The osteogenic differentiation effects of two types of HCG scaffolds on hiPSCs were assessed for up to 12 weeks. The results showed that HCG-311 increased osteogenic-related gene expression of hiPSCs in vitro proved by quantitative real-time polymerase chain reaction, and hiPSC/HCG-311 complexes formed much bone-like tissue in vivo, indicated by cone-beam computed tomography imaging, H&E staining, Masson staining, and RUNX-2, OCN immunohistochemistry staining. In conclusion, our study has shown that osteogenic differentiation of hiPSCs from hGFs was improved by HCG-311. The mechanism might be that the nHA addition stimulates osteogenic marker expression of hiPSCs from hGFs. Our work has provided an innovative autologous cell-based bone tissue engineering approach with soft tissues such as clinically abundant gingiva. The present study focused on patient-personalized bone tissue engineering. Human induced pluripotent stem cells

  7. Chitosan-based scaffolds for bone tissue engineering

    PubMed Central

    Levengood, Sheeny Lan; Zhang, Miqin

    2014-01-01

    Bone defects requiring grafts to promote healing are frequently occurring and costly problems in health care. Chitosan, a biodegradable, naturally occurring polymer, has drawn considerable attention in recent years as scaffolding material in tissue engineering and regenerative medicine. Chitosan is especially attractive as a bone scaffold material because it supports the attachment and proliferation of osteoblast cells as well as formation of mineralized bone matrix. In this review, we discuss the fundamentals of bone tissue engineering and the unique properties of chitosan as a scaffolding material to treat bone defects for hard tissue regeneration. We present the common methods for fabrication and characterization of chitosan scaffolds, and discuss the influence of material preparation and addition of polymeric or ceramic components or biomolecules on chitosan scaffold properties such as mechanical strength, structural integrity, and functional bone regeneration. Finally, we highlight recent advances in development of chitosan-based scaffolds with enhanced bone regeneration capability. PMID:24999429

  8. Covalently Bonded Chitosan on Graphene Oxide via Redox Reaction

    PubMed Central

    Bustos-Ramírez, Karina; Martínez-Hernández, Ana L.; Martínez-Barrera, Gonzalo; de Icaza, Miguel; Castaño, Víctor M.; Velasco-Santos, Carlos

    2013-01-01

    Carbon nanostructures have played an important role in creating a new field of materials based on carbon. Chemical modification of carbon nanostructures through grafting has been a successful step to improve dispersion and compatibility in solvents, with biomolecules and polymers to form nanocomposites. In this sense carbohydrates such as chitosan are extremely valuable because their functional groups play an important role in diversifying the applications of carbon nanomaterials. This paper reports the covalent attachment of chitosan onto graphene oxide, taking advantage of this carbohydrate at the nanometric level. Grafting is an innovative route to modify properties of graphene, a two-dimensional nanometric arrangement, which is one of the most novel and promising nanostructures. Chitosan grafting was achieved by redox reaction using different temperature conditions that impact on the morphology and features of graphene oxide sheets. Transmission Electron Microscopy, Fourier Transform Infrared, Raman and Energy Dispersive spectroscopies were used to study the surface of chitosan-grafted-graphene oxide. Results show a successful modification indicated by the functional groups found in the grafted material. Dispersions of chitosan-grafted-graphene oxide samples in water and hexane revealed different behavior due to the chemical groups attached to the graphene oxide sheet. PMID:28809348

  9. Covalently Bonded Chitosan on Graphene Oxide via Redox Reaction.

    PubMed

    Bustos-Ramírez, Karina; Martínez-Hernández, Ana L; Martínez-Barrera, Gonzalo; Icaza, Miguel de; Castaño, Víctor M; Velasco-Santos, Carlos

    2013-03-07

    Carbon nanostructures have played an important role in creating a new field of materials based on carbon. Chemical modification of carbon nanostructures through grafting has been a successful step to improve dispersion and compatibility in solvents, with biomolecules and polymers to form nanocomposites. In this sense carbohydrates such as chitosan are extremely valuable because their functional groups play an important role in diversifying the applications of carbon nanomaterials. This paper reports the covalent attachment of chitosan onto graphene oxide, taking advantage of this carbohydrate at the nanometric level. Grafting is an innovative route to modify properties of graphene, a two-dimensional nanometric arrangement, which is one of the most novel and promising nanostructures. Chitosan grafting was achieved by redox reaction using different temperature conditions that impact on the morphology and features of graphene oxide sheets. Transmission Electron Microscopy, Fourier Transform Infrared, Raman and Energy Dispersive spectroscopies were used to study the surface of chitosan-grafted-graphene oxide. Results show a successful modification indicated by the functional groups found in the grafted material. Dispersions of chitosan-grafted-graphene oxide samples in water and hexane revealed different behavior due to the chemical groups attached to the graphene oxide sheet.

  10. Construction and characterization of Gal-chitosan graft methoxy poly (ethylene glycol) (Gal-CS-mPEG) nanoparticles as efficient gene carrier

    NASA Astrophysics Data System (ADS)

    Jin, Jiting; Fu, Wandong; Liao, Miaofei; Han, Baoqin; Chang, Jing; Yang, Yan

    2017-10-01

    In the present study, galactosylated chitosan (Gal-CS) was conjugated with methoxy poly(ethylene glycol) (mPEG) as a hydrophilic group. The structure of Gal-CS-mPEG polymer was characterized and the nanoparticles (NPs) were prepared using ironic gelation method. The study was designed to investigate the characteristics and functions of Gal-CS-mPEG NPs. The morphology of Gal-CS-mPEG NPs was observed by SEM and it was a compact and spherical shape. The size of the NPs was approximately 200 nm in diameter under the ideal process parameters. The interaction between Gal-CS-mPEG NPs and pDNA, and the protection of pDNA against DNase I and serum degradation by Gal-CS-mPEG NPs were evaluated. Agarose gel electrophoresis results showed that Gal-CS-mPEG NPs had strong interaction with pDNA at the weight ratio of 12:1, 4:1 and 2:1 and could protect pDNA from DNase I and serum degradation. Gal-CS-mPEG NPs exhibited high loading efficiency and sustainable in vitro release. The blood compatibility studies demonstrated that Gal-CS-mPEG NPs had superior compatibility with erythrocytes in terms of aggregation degree and hemolysis level. Gal-CS-mPEG NPs showed no cytotoxicity on L929 cells, which is a normal mouse connective tissue fibroblast, but showed inhibitory effects on the proliferation of Bel-7402 cells, which is a liver cancer cell line. In conclusion, Gal-CS-mPEG NP is a bio-safe and efficient gene carrier with potential application in gene delivery.

  11. Skin graft

    MedlinePlus

    ... that need skin grafts to heal Venous ulcers, pressure ulcers , or diabetic ulcers that do not heal Very ... graft; Full thickness skin graft Patient Instructions Preventing pressure ulcers Surgical wound care - open Images Skin graft Skin ...

  12. Chitosan dermal substitute and chitosan skin substitute contribute to accelerated full-thickness wound healing in irradiated rats.

    PubMed

    Mohd Hilmi, Abu Bakar; Halim, Ahmad Sukari; Jaafar, Hasnan; Asiah, Abu Bakar; Hassan, Asma

    2013-01-01

    Wounds with full-thickness skin loss are commonly managed by skin grafting. In the absence of a graft, reepithelialization is imperfect and leads to increased scar formation. Biomaterials can alter wound healing so that it produces more regenerative tissue and fewer scars. This current study use the new chitosan based biomaterial in full-thickness wound with impaired healing on rat model. Wounds were evaluated after being treated with a chitosan dermal substitute, a chitosan skin substitute, or duoderm CGF. Wounds treated with the chitosan skin substitute showed the most re-epithelialization (33.2 ± 2.8%), longest epithelial tongue (1.62 ± 0.13 mm), and shortest migratory tongue distance (7.11 ± 0.25 mm). The scar size of wounds treated with the chitosan dermal substitute (0.13 ± 0.02 cm) and chitosan skin substitute (0.16 ± 0.05 cm) were significantly decreased (P < 0.05) compared with duoderm (0.45 ± 0.11 cm). Human leukocyte antigen (HLA) expression on days 7, 14, and 21 revealed the presence of human hair follicle stem cells and fibroblasts that were incorporated into and surviving in the irradiated wound. We have proven that a chitosan dermal substitute and chitosan skin substitute are suitable for wound healing in full-thickness wounds that are impaired due to radiation.

  13. Chitosan Dermal Substitute and Chitosan Skin Substitute Contribute to Accelerated Full-Thickness Wound Healing in Irradiated Rats

    PubMed Central

    Mohd Hilmi, Abu Bakar; Halim, Ahmad Sukari; Jaafar, Hasnan; Asiah, Abu Bakar; Hassan, Asma

    2013-01-01

    Wounds with full-thickness skin loss are commonly managed by skin grafting. In the absence of a graft, reepithelialization is imperfect and leads to increased scar formation. Biomaterials can alter wound healing so that it produces more regenerative tissue and fewer scars. This current study use the new chitosan based biomaterial in full-thickness wound with impaired healing on rat model. Wounds were evaluated after being treated with a chitosan dermal substitute, a chitosan skin substitute, or duoderm CGF. Wounds treated with the chitosan skin substitute showed the most re-epithelialization (33.2 ± 2.8%), longest epithelial tongue (1.62 ± 0.13 mm), and shortest migratory tongue distance (7.11 ± 0.25 mm). The scar size of wounds treated with the chitosan dermal substitute (0.13 ± 0.02 cm) and chitosan skin substitute (0.16 ± 0.05 cm) were significantly decreased (P < 0.05) compared with duoderm (0.45 ± 0.11 cm). Human leukocyte antigen (HLA) expression on days 7, 14, and 21 revealed the presence of human hair follicle stem cells and fibroblasts that were incorporated into and surviving in the irradiated wound. We have proven that a chitosan dermal substitute and chitosan skin substitute are suitable for wound healing in full-thickness wounds that are impaired due to radiation. PMID:24324974

  14. Laccase-catalysed functionalisation of chitosan by ferulic acid and ethyl ferulate: evaluation of physicochemical and biofunctional properties.

    PubMed

    Aljawish, Abdulhadi; Chevalot, Isabelle; Jasniewski, Jordane; Revol-Junelles, Anne-Marie; Scher, Joël; Muniglia, Lionel

    2014-10-15

    Chitosan and its derivatives functionalized by laccase-catalyzed oxidation of ferulic acid (FA) and ethyl ferulate (EF) were characterised for their physico-chemical, antioxidant and antibacterial properties. The enzymatic grafting of oxidised phenols led to FA-coloured and EF-colourless chitosan derivatives with good stability of colour and grafted phenols towards the chemical treatment by organic solvents. The efficiency of FA-products grafting onto chitosan was higher than that of EF-products. Moreover, the enzymatic grafting of phenols onto chitosan changed its morphological surface, increased its molecular weight and its viscosity. Furthermore, the chitosan derivatives presented improved antioxidant properties especially for FA-chitosan derivative when compared with chitosan with good antioxidant stability towards thermal treatment (100°C/1h). Chitosan and its derivatives showed also similar antibacterial activities and more precisely bactericidal activities. This enzymatic procedure provided chitosan derivatives with improved properties such as antioxidant activity, thermal antioxidant stability as well as the preservation of initial antibacterial activity of chitosan.

  15. Co-delivery of adipose-derived stem cells and growth factor-loaded microspheres in RGD-grafted N-methacrylate glycol chitosan gels for focal chondral repair.

    PubMed

    Sukarto, Abby; Yu, Claire; Flynn, Lauren E; Amsden, Brian G

    2012-08-13

    The coencapsulation of growth factor-loaded microspheres with adipose-derived stem cells (ASCs) within a hydrogel matrix was studied as a potential means to enhance ASC chondrogenesis in the development of a cell-based therapeutic strategy for the regeneration of partial thickness chondral defects. A photopolymerizable N-methacrylate glycol chitosan (MGC) was employed to form an in situ gel used to encapsulate microspheres loaded with bone morphogenetic protein 6 (BMP-6) and transforming growth factor-β3 (TGF-β3) with human ASCs. ASC viability and retention were enhanced when the Young's modulus of the MGC ranged between 225 and 380 kPa. Grafting an RGD-containing peptide onto the MGC backbone (RGD-MGC) improved ASC viability within the gels, remaining at greater than 90% over 14 days in culture. The effects of BMP-6 and TGF-β3 released from the polymer microspheres on ASC chondrogenesis were assessed, and the level of differentiation was compared to ASCs in control gels containing nongrowth factor-loaded microspheres cultured with and without the growth factors supplied in the medium. There was enhanced expression of chondrogenic markers at earlier time points when the ASCs were induced with the sustained and local release of BMP-6 and TGF-β3 from the microspheres. More specifically, the normalized glycosaminoglycan and collagen type II protein expression levels were significantly higher than in the controls. In addition, the ratio of collagen type II to type I was significantly higher in the microsphere delivery group and increased over time. End-point RT-PCR analysis supported that there was a more rapid induction and enhancement of ASC chondrogenesis in the controlled release group. Interestingly, in all of the assays, there was evidence of chondrogenic differentiation when the ASCs were cultured in the gels in the absence of growth factor stimulation. Overall, the co-delivery of growth-factor-loaded microspheres and ASCs in RGD-modified MGC gels

  16. Pullout strength of fixation screws from polymethylmethacrylate bone cement.

    PubMed

    Flahiff, C M; Gober, G A; Nicholas, R W

    1995-05-01

    Polymethylmethacrylate bone cement is often used to fill voids and increase the strength of osteoporotic and pathological bone. However, it is unclear as to which method of cement augmentation provides optimal screw fixation. This study was conducted to determine which of the current cement augmentation techniques provides the strongest construct when used in association with orthopaedic fixation screws. Pullout strength was determined for screws placed in sawbones with no cement, soft cement, doughy cement and hard cement after drilling and tapping. All cement-screw constructs were significantly stronger than the no cement group. Screws placed in doughy cement had a significantly higher pullout force than those placed in hard cement. Pullout strength of screws placed in soft cement was intermediate between the other cement techniques but not significantly different from either group.

  17. Gold-implanted shallow conducting layers in polymethylmethacrylate

    SciTech Connect

    Teixeira, F. S.; Salvadori, M. C.; Cattani, M.; Brown, I. G.

    2009-03-15

    PMMA (polymethylmethacrylate) was ion implanted with gold at very low energy and over a range of different doses using a filtered cathodic arc metal plasma system. A nanometer scale conducting layer was formed, fully buried below the polymer surface at low implantation dose, and evolving to include a gold surface layer as the dose was increased. Depth profiles of the implanted material were calculated using the Dynamic TRIM computer simulation program. The electrical conductivity of the gold-implanted PMMA was measured in situ as a function of dose. Samples formed at a number of different doses were subsequently characterized by Rutherford backscattering spectrometry, and test patterns were formed on the polymer by electron beam lithography. Lithographic patterns were imaged by atomic force microscopy and demonstrated that the contrast properties of the lithography were well maintained in the surface-modified PMMA.

  18. A novel method for synthesizing PEGylated chitosan nanoparticles: strategy, preparation, and in vitro analysis

    PubMed Central

    Malhotra, Meenakshi; Lane, Ciaran; Tomaro-Duchesneau, Catherine; Saha, Shyamali; Prakash, Satya

    2011-01-01

    Preparation of poly (ethylene glycol) (PEG)-grafted chitosan is essential for improving the biocompatibility and water solubility of chitosan. Presently available methods for this have limitations. This article describes a new method for preparing PEGylated chitosan nanoparticles. For this chitosan was chemoselectively modified using a novel scheme at the C6 position of its repeating units by PEG. The amine groups at the C2 position of the chitosan were protected using phthalic anhydride. Sodium hydride was used to catalyze the etherification reaction between chlorinated chitosan and methyl-PEG, and PEG-grafted chitosan was successfully synthesized. Each step was characterized using 13C nuclear magnetic resonance and Fourier transform infrared. After PEGylation the phthaloylated chitosan was successfully deprotected using hydrazine monohydrate. The synthetic scheme proposed demonstrates a new method for grafting PEG onto chitosan with a moderate degree of substitution. The potential of this polymer in nanoparticle preparation using an ionic gelation method and its gene delivery potentials were investigated by complexing a fluorescently labeled control siRNA. The result showed that suitable nanoparticles can be synthesized using this polymer and that they have capacity to carry genes and provide adequate transfection efficacy with no toxicity when tested in neuronal cells. PMID:21562608

  19. Environmental applications of chitosan and its derivatives.

    PubMed

    Yong, Soon Kong; Shrivastava, Manoj; Srivastava, Prashant; Kunhikrishnan, Anitha; Bolan, Nanthi

    2015-01-01

    , hydraulic conductivity, permeability, surface area and sorption capacity. Crosslinked chitosan is an excellent sorbent for trace metals especially because of the high flexibility of its structural stability. Sorption of trace metals by chitosan is selective and independent of the size and hardness of metal ions, or the physical form of chitosan (e.g., film, powder and solution). Both -OH and -NH2 groups in chitosan provide vital binding sites for complexing metal cations. At low pH, -NH3 + groups attract and coagulate negatively charged contaminants such as metal oxyanions, humic acids and dye molecules. Grafting certain functional molecules into the chitin structure improves sorption capacity and selectivity for remediating specific metal ions. For example, introducing sulfur and nitrogen donor ligands to chitosan alters the sorption preference for metals. Low molecular weight chitosan derivatives have been used to remediate metal contaminated soil and sediments. They have also been applied in permeable reactive barriers to remediate metals in soil and groundwater. Both chitosan and modified chitosan have been used to phytoremediate metals; however, the mechanisms by which they assist in mobilizing metals are not yet well understood. In addition, microbes have been used in combination with chitosan to remediate metals (e.g., Cu and Zn) in contaminated soils. Chitosan has also been used to remediate organic contaminants, such as oil-based wastewater, dyes, tannins, humic acids, phenols, bisphenoi-A, p-benzoquinone, organo-phosphorus insecticides, among others. Chitosan has also been utilized to develop optical and electrochemical sensors for in-situ detection of trace contaminants. In sensor technology, naturally-derived chitosan is used primarily as an immobilizing agent that results from its enzyme compatibility, and stabilizing effect on nanoparticles. Contaminant-sensing agents, such as enzymes, microbes and nanoparticles, have been homogeneously immobilized in chitosan

  20. Bone graft

    MedlinePlus

    Autograft - bone; Allograft - bone; Fracture - bone graft; Surgery - bone graft; Autologous bone graft ... Fuse joints to prevent movement Repair broken bones (fractures) that have bone loss Repair injured bone that ...

  1. In vivo study of chitosan-natural nano hydroxyapatite scaffolds for bone tissue regeneration.

    PubMed

    Lee, Jong Seo; Baek, Sang Dae; Venkatesan, Jayachandran; Bhatnagar, Ira; Chang, Hee Kyung; Kim, Hui Taek; Kim, Se-Kwon

    2014-06-01

    Significant development has been achieved with bioceramics and biopolymer scaffolds in the construction of artificial bone. In the present study, we have developed and compared chitosan-micro hydroxyapatite (chitosan-mHA) and chitosan-nano hydroxyapatite (chitosan-nHA) scaffolds as bone graft substitutes. The biocompatibility and cell proliferation of the prepared scaffolds were checked with preosteoblast (MC3T3-E1) cells. Total Volume (TV), bone volume (BV), bone surface (BS), trabecular thickness (Tb.Th), trabecular number (Tb.N) and trabecular separation (Tb.Sp) were found to be higher in chitosan-nHA than chitosan-mHA scaffold. Hence, we suggest that chitosan-nHA scaffold could be a promising biomaterial for bone tissue engineering. Copyright © 2014 Elsevier B.V. All rights reserved.

  2. Enzymatic modification of chitosan by cinnamic acids: Antibacterial activity against Ralstonia solanacearum.

    PubMed

    Yang, Caifeng; Zhou, Yu; Zheng, Yu; Li, Changlong; Sheng, Sheng; Wang, Jun; Wu, Fuan

    2016-06-01

    This study aimed to identify chitosan polymers that have antibacterial activity against the bacterial wilt pathogen. The chitosan polymers were enzymatically synthesized using chitosan and five cinnamic acids (CADs): caffeic acid (CA), ferulic acid (FA), cinnamic acid (CIA), p-coumaric acid (COA) and chlorogenic acid (CHA), using laccase from Pleurotus ostreatus as a catalyst. The reaction was performed in a phosphate buffered solution under heterogenous reaction conditions. The chitosan derivatives (CTS-g-CADs) were characterized by FT-IR, XRD, TGA and SEM. FT-IR demonstrated that the reaction products bound covalently to the free amino groups or hydroxyl groups of chitosan via band of amide I or ester band. XRD showed a reduced packing density for grafted chitosan comparing to original chitosan. TGA demonstrated that CTS-g-CADs have a higher thermostability than chitosan. Additionally, chitosan and its derivatives showed similar antibacterial activity. However, the IC50 value of the chitosan-caffeic acid derivative (CTS-g-CA) against the mulberry bacterial wilt pathogen RS-5 was 0.23mg/mL, which was two-fifths of the IC50 value of chitosan. Therefore, the enzymatically synthesized chitosan polymers can be used to control plant diseases in biotechnological domains.

  3. Hg(II) removal from water by chitosan and chitosan derivatives: a review.

    PubMed

    Miretzky, P; Cirelli, A Fernandez

    2009-08-15

    Mercury (Hg) is one of the most toxic heavy metals commonly found in the global environment. Its toxicity is related to the capacity of its compounds to bioconcentrate in organisms and to biomagnify through food chain. A wide range of adsorbents has been used for removing Hg(II) from contaminated water. Chitosan is obtained by alkaline deacetylation of chitin. The adsorption capacity of chitosan depends on the origin of the polysaccharide, and on the experimental conditions in the preparation, that determine the degree of deacetylation. A great number of chitosan derivatives have been obtained by crosslinking with glutaraldehyde or epichlorohydrin among others or by grafting new functional groups on the chitosan backbone with the aim of adsorbing Hg(II). The new functional groups are incorporated to change the pH range for Hg(II) sorption and/or to change the sorption sites in order to increase sorption selectivity. The chemical modification affords a wide range of derivatives with modified properties for specific applications. Hg(II) adsorption on chitosan or chitosan derivatives is now assumed to occur through several single or mixed interactions: chelation or coordination on amino groups in a pendant fashion or in combination with vicinal hydroxyl groups, electrostatic attraction in acidic media or ion exchange with protonated amino groups. This review reports the recent developments in the Hg(II) removal in waste water treatment, using chitosan and its derivatives in order to provide useful information about the different technologies. When possibly the adsorption capacity of chitosan and chitosan derivatives under different experimental conditions is reported to help to compare the efficacy of the Hg(II) removal process. A comparison with the adsorption capacity of other low-cost adsorbents is also tabled.

  4. Nitric oxide-releasing chitosan oligosaccharides as antibacterial agents.

    PubMed

    Lu, Yuan; Slomberg, Danielle L; Schoenfisch, Mark H

    2014-02-01

    Secondary amine-functionalized chitosan oligosaccharides of different molecular weights (i.e., ~2500, 5000, 10,000) were synthesized by grafting 2-methyl aziridine from the primary amines on chitosan oligosaccharides, followed by reaction with nitric oxide (NO) gas under basic conditions to yield N-diazeniumdiolate NO donors. The total NO storage, maximum NO flux, and half-life of the resulting NO-releasing chitosan oligosaccharides were controlled by the molar ratio of 2-methyl aziridine to primary amines (e.g., 1:1, 2:1) and the functional group surrounding the N-diazeniumdiolates (e.g., polyethylene glycol (PEG) chains), respectively. The secondary amine-modified chitosan oligosaccharides greatly increased the NO payload over existing biodegradable macromolecular NO donors. In addition, the water-solubility of the chitosan oligosaccharides enabled their penetration across the extracellular polysaccharides matrix of Pseudomonas aeruginosa biofilms and association with embedded bacteria. The effectiveness of these chitosan oligosaccharides at biofilm eradication was shown to depend on both the molecular weight and ionic characteristics. Low molecular weight and cationic chitosan oligosaccharides exhibited rapid association with bacteria throughout the entire biofilm, leading to enhanced biofilm killing. At concentrations resulting in 5-log killing of bacteria in Pseudomonas aeruginosa (P. aeruginosa) biofilms, the NO-releasing and control chitosan oligosaccharides elicited no significant cytotoxicity to mouse fibroblast L929 cells in vitro. Copyright © 2013 Elsevier Ltd. All rights reserved.

  5. Nitric Oxide-Releasing Chitosan Oligosaccharides as Antibacterial Agents

    PubMed Central

    Lu, Yuan; Slomberg, Danielle L.; Schoenfisch, Mark H.

    2014-01-01

    Secondary amine-functionalized chitosan oligosaccharides of different molecular weights (i.e., ~2500, 5000, 10000) were synthesized by grafting 2-methyl aziridine from the primary amines on chitosan oligosaccharides, followed by reaction with nitric oxide (NO) gas under basic conditions to yield N-diazeniumdiolate NO donors. The total NO storage, maximum NO flux, and half-life of the resulting NO-releasing chitosan oligosaccharides were controlled by the molar ratio of 2-methyl aziridine to primary amines (e.g., 1:1, 2:1) and the functional group surrounding the N-diazeniumdiolates (e.g., polyethylene glycol (PEG) chains), respectively. The secondary amine-modified chitosan oligosaccharides greatly increased the NO payload over existing biodegradable macromolecular NO donors. In addition, the water-solubility of the chitosan oligosaccharides enabled their penetration across the extracellular polysaccharides matrix of Pseudomonas aeruginosa biofilms and association with embedded bacteria. The effectiveness of these chitosan oligosaccharides at biofilm eradication was shown to depend on both the molecular weight and ionic characteristics. Low molecular weight and cationic chitosan oligosaccharides exhibited rapid association with bacteria throughout the entire biofilm, leading to enhanced biofilm killing. At concentrations resulting in 5-log killing of bacteria in Pseudomonas aeruginosa biofilms, the NO-releasing and control chitosan oligosaccharides elicited no significant cytotoxicity to mouse fibroblast L929 cells in vitro. PMID:24268196

  6. Synthesis and self-assembly of chitosan-g-polystyrene copolymer: a new route for the preparation of heavy metal nanoparticles.

    PubMed

    Francis, Raju; Baby, Deepa K; Gnanou, Yves

    2015-01-15

    Amphiphilic graft copolymers made of a Chitosan (CS) backbone and three arm polystyrene (PS) grafts were prepared by "grafting onto" strategy using Toluene Diisocyanate. IR spectroscopy and SEC show the successful grafting process. SEM pictures of Chitosan-g-Polystyrene (CS-g-PS) indicate a spherulite like surface and exhibit properties that result from the disappearance of Chitosan crystallinity. The introduced polystyrene star grafts units improve hydrophobic properties considerably as confirmed by the very high solubility of (CS-g-PS) in organic solvents. The graft copolymer which self-assembles into polymeric micelles in organic media demonstrates much better adsorption of transition and inner transition metal ions than pure Chitosan whose amine groups are not necessarily available due to crystallinity.

  7. The preparation and antioxidant activity of the sulfanilamide derivatives of chitosan and chitosan sulfates.

    PubMed

    Zhong, Zhimei; Ji, Xia; Xing, Ronge; Liu, Song; Guo, Zhanyong; Chen, Xiaolin; Li, Pengcheng

    2007-06-01

    Chitosan (CS) and chitosan sulfates (CSS) with different molecular weight (Mw) were reacted with 4-acetamidobenzene sulfonyl chloride to obtain sulfanilamide derivatives of chitosan and chitosan sulfates (LSACS, HSACS, LSACSS, HSACSS). The preparation conditions such as different reaction time, temperature, solvent, and the molar ratio of reaction materials are discussed in this paper. Their structures were characterized by FTIR spectroscopy and elemental analyses. The antioxidant activities of the derivatives were investigated employing various established in vitro systems, such as hydroxyl-radical ((*)OH) superoxide anion (O2(*-)) scavenging and reducing power. All kinds of the compounds (HCS, LCS, HCSS, LCSS, HSACS, LSACS, HSACSS, LSACSS) showed stronger scavenging activity on hydroxyl radical than ascorbic acid (Vc). The inhibitory activities of the derivatives toward superoxide radical by the PMS-NADH system were obvious. The experiment showed that the superoxide radical scavenging effect of sulfanilamide derivatives of chitosan and chitosan sulfates was stronger than that of original CS and CSS. All of the derivatives were efficient in the reducing power. The results indicated that the sulfanilamide group were grafted on CS and CSS increased the reducing power of them obviously.

  8. Polymethylmethacrylate-induced release of bone-resorbing factors

    SciTech Connect

    Herman, J.H.; Sowder, W.G.; Anderson, D.; Appel, A.M.; Hopson, C.N. )

    1989-12-01

    A pseudomembranous structure that has the histological characteristics of a foreign-body-like reaction invariably develops at the bone-cement interface in the proximity of resorption of bone around aseptically loosened cemented prostheses. This study was an attempt to implicate polymethylmethacrylate in this resorptive process. Unfractionated peripheral-blood mononuclear cells (consisting of lymphocytes and monocytes) and surface-adherent cells (monocyte-enriched) were prepared from control subjects who did and did not have clinical evidence of osteoarthrosis and from patients who had osteoarthrosis and were having a revision for failure of a cemented hip or knee implant. Cells were cultured for varying periods in the presence and absence of nonpolymerized methacrylate (one to two-micrometer spherules), pulverized polymerized material, or culture chambers that were pre-coated with polymerized cement. Conditioned media that were derived from both methacrylate-stimulated cell populations were shown to contain specific bone-resorbing mediators (interleukin-1, tumor necrosis factor, or prostaglandin E2) and to directly affect bone resorption in 45Ca-labeled murine limb-bone assays.

  9. A poly-methylmethacrylate electrophoresis microchip with sample preconcentrator

    NASA Astrophysics Data System (ADS)

    Lin, Yu-Cheng; Ho, Hsiao-Ching; Tseng, Chien-Kai; Hou, Shao-Qin

    2001-05-01

    A microstructure on poly-methylmethacrylate (PMMA) for sample concentration and electrophoresis was fabricated. This microfabricated structure was able to increase the detection signal and lower the amount of sample used in electrophoretic analysis. The thin-film electrode located at the T-intersection of the sample injection and separation channels provides the current path for the injection channel, but restrains the DNA molecules from passing through. This can accumulate DNA molecules and increase the concentration before performing the electrophoretic analysis. This microstructure was fabricated using krypton fluoride (KrF) excimer laser photo-ablation and fusion bonding techniques. The excimer laser photo-ablation performs rapid prototyping with great flexibility in design changes. The PMMA material is much cheaper than other materials, for example glass and silicon, used in capillary electrophoresis and concentration. The applied electrical field was 300 V cm-1 for the DNA concentration in this microstructure. Experiments show that the DNA concentration was saturated within 200 s after the DNA molecules first reached the injection tee. The DNA fragments can be concentrated up to five times greater than samples without a concentrator at the injection tee. The separation results also demonstrated that the detected signal intensities of the separated DNA fragments in the tee-type chip with a sample preconcentrator were five times greater than that obtained in a conventional cross-type capillary electrophoresis chip with an identical initial sample concentration.

  10. Surface engineering of poly(methylmethacrylate): Effects on fluorescence immunoassay.

    PubMed

    Akers, Peter W; Hoai Le, Nam Cao; Nelson, Andrew R J; McKenna, Milena; O'Mahony, Christy; McGillivray, Duncan J; Gubala, Vladimir; Williams, David E

    2017-06-06

    The authors present surface engineering modifications through chemistry of poly(methylmethacrylate) (PMMA) that have dramatic effects on the result of surface-bound fluorescence immunoassays, both for specific and nonspecific signals. The authors deduce the most important effect to be clustering of antibodies on the surface leading to significant self-quenching. Secondary effects are attributable to the formation of sparse multilayers of antibody. The authors compare PMMA as an antibody support surface with ultraviolet-ozone oxidized PMMA and also to substrates that were, after the oxidation, surface modified by a four-unit poly(ethyleneglycol) carboxylic acid (PEG4), a branched tricarboxylic acid, and a series of carboxylic acid-terminated dendrimers, from generation 1.5 to 5.5. Fluorescence immunoassay and neutron reflectometry were used to compare the apparent antibody surface loading, antigen binding and nonspecific binding on these various surfaces using anti-human IgG as a model antibody, chemically coupled to the surface by amide formation. Simple physical adsorption of the antibody on PMMA resulted in a thick antibody multilayer with small antigen binding capacity. On the carboxylated surfaces, with chemical coupling, a simple monolayer was formed. The authors deduce that antibody clustering was driven by conformational inflexibility and high carboxylate density. The PEG4-modified surface was the most conformationally flexible. The dendrimer-modified interfaces showed a collapse and densification. In fluorescence immunoassay, the optimal combination of high specific and low nonspecific fluorescence signal was found for the G3.5 dendrimer.

  11. Integrity of Polymethylmethacrylate (PMMA) Chemically Welded Joints Examined

    NASA Technical Reports Server (NTRS)

    Lerch, Bradley A.; Thesken, John C.; Bunnell, Charles T.; Kurta, Carol E.; Sydenstricker, Mike

    2005-01-01

    NASA Glenn Research Center s Capillary Flow Experiments (CFE) program is developing experiment payloads to explore fluid interfaces in microgravity on the International Space Station. The information to be gained from the CFE is relevant to the design of fluid-bearing systems in which capillary forces predominate, for example in the passive positioning of liquids in spacecraft fuel tanks. To achieve the science goals of CFE, Glenn researchers constructed several types of experiment vessels. One type of vessel, known as the interior corner flow (ICF), will be used to determine important transients for low-gravity liquid management in a two-phase system. Each vessel has a cylindrical fluid reservoir connected to each end of the test chamber by internal transport tubes, each with a quarter-turn shutoff valve (see the following photograph). These multipiece vessels are made from polymethylmethacrylate (PMMA) because of its excellent optical properties (i.e., the fluids can be observed easily in the vessel). Because of the complexity of certain vessels, the test chamber had to be manufactured in pieces and welded chemically. Some past experience with adhesive bonded plastic showed that the experiment fluid degraded the adhesive to the point of failure. Therefore, it was necessary to see if the fluid also degraded the chemically welded PMMA joints.

  12. Polymethylmethacrylate dermal fillers: evaluation of the systemic toxicity in rats.

    PubMed

    Medeiros, C C G; Borghetti, R L; Nicoletti, N; da Silva, V D; Cherubini, K; Salum, F G; de Figueiredo, M A Z

    2014-01-01

    This study evaluated local and systemic reactions after an intravascular injection of polymethylmethacrylate (PMMA) at two concentrations in a murine model. Thirty rats were divided equally into three groups: 2% PMMA, 30% PMMA, and a control group (normal saline only injection). The filler was injected into the ranine vein. The rats were sedated at 7 and 90 days and a clinical evaluation performed. After euthanasia, the right lung, liver, and right kidney were removed, weighed, and microscopically analyzed. The submandibular lymph nodes and tongue were removed and examined microscopically. Serum was subjected to liver and kidney function tests. No groups showed clinical alterations. Microspheres were not observed at any distant organ. Two samples from the 2% PMMA group showed a local inflammatory response at day 7 and another two samples from the 30% PMMA group at day 90. The group injected with 30% PMMA presented higher levels of alanine aminotransferase (P = 0.047) after 90 days when compared with the other groups. The data obtained in this study demonstrate that intravascular injections of PMMA fillers show potential health risks such as chronic inflammation at the implantation site.

  13. Extraction of chitosan from shrimp shells waste and application in antibacterial finishing of bamboo rayon.

    PubMed

    Teli, M D; Sheikh, Javed

    2012-06-01

    Chitosan can be best utilized as safe antibacterial agent for textiles but there is always a limitation of its durability. The chitin containing shellfish waste is available in huge quantities, but very low quantities are utilized for extraction of high value products like chitosan. In the current work chitosan was extracted from shrimp shells and then used as antibacterial exhaust finishing agent for grafted bamboo rayon. Chitosan bound bamboo rayon was then evaluated for antibacterial activity against both gram positive and gram negative bacteria. The product showed antibacterial activity against both types of bacterias which was durable till 30 washes.

  14. Acrylated chitosan for mucoadhesive drug delivery systems.

    PubMed

    Shitrit, Yulia; Bianco-Peled, Havazelet

    2017-01-30

    A new mucoadhesive polymer was synthesized by conjugating chitosan to poly(ethylene glycol)diacrylate (PEGDA) via the Michael type reaction. The product was characterized using NMR. Higher PEGDA grafting efficacy was observed with low molecular weight PEGDA (0.7kDa), compared to long 10kDa PEGDA. The acrylation percentage was calculated based on the reaction of ninhydrin with chitosan, and supported the qualitative NMR findings. The adhesive properties were studied by tensile test and rotating system involving detachment of polymer tablets from a fresh intestine sample. Chitosan modified with high molecular weight PEGDA presented improvement in mucoadhesive properties compared to both non-modified and thiolated chitosan. On the molecular level, rheology measurements of polymer/mucin mixtures provided additional evidence of strong interaction between modified chitosan and mucin glycoproteins. This new polymer shows promise as a useful polymeric carrier matrix for delivery systems, which could provide prolonged residence time of the vehicle on the mucosa surface. Copyright © 2016 Elsevier B.V. All rights reserved.

  15. Methacrylated glycol chitosan as a photopolymerizable biomaterial.

    PubMed

    Amsden, Brian G; Sukarto, Abby; Knight, Darryl K; Shapka, Stephen N

    2007-12-01

    Glycol chitosan is a derivative of chitosan that is soluble at neutral pH and possesses potentially useful biological properties. With the goal of obtaining biocompatible hydrogels for use as tissue engineering scaffolds or drug delivery depots, glycol chitosan was converted to a photopolymerizable prepolymer through graft methacrylation using glycidyl methacrylate in aqueous media at pH 9. N-Methacrylation was verified by both (1)H NMR and (13)C NMR. The degree of N-methacrylation, measured via (1)H NMR, was easily varied from 1.5% to approximately 25% by varying the molar ratio of glycidyl methacrylate to glycol chitosan and the reaction time. Using a chondrocyte cell line, the N-methacrylated glycol chitosan was found to be noncytotoxic up to a concentration of 1 mg/mL. The prepolymer was cross-linked in solution using UV light and Irgacure 2959 photoinitiator under various conditions to yield gels of low sol content ( approximately 5%), high equilibrium water content (85-95%), and thicknesses of up to 6 mm. Cross-polarization magic-angle spinning (13)C solid state NMR verified the complete conversion of the double bonds in the gel. Chondrocytes seeded directly onto the gel surface, populated the entirety of the gel and remained viable for up to one week. The hydrogels degraded slowly in vitro in the presence of lysozyme at a rate that increased as the cross-link density of the gels decreased.

  16. Chitosan-g-lactide copolymers for fabrication of 3D scaffolds for tissue engineering

    NASA Astrophysics Data System (ADS)

    Demina, T. S.; Zaytseva-Zotova, D. S.; Timashev, P. S.; Bagratashvili, V. N.; Bardakova, K. N.; Sevrin, Ch; Svidchenko, E. A.; Surin, N. M.; Markvicheva, E. A.; Grandfils, Ch; Akopova, T. A.

    2015-07-01

    Chitosan-g-oligo (L, D-lactide) copolymers were synthesized and assessed to fabricate a number of 3D scaffolds using a variety of technologies such as oil/water emulsion evaporation technique, freeze-drying and two-photon photopolymerization. Solid-state copolymerization method allowed us to graft up to 160 wt-% of oligolactide onto chitosan backbone via chitosan amino group acetylation with substitution degree reaching up to 0.41. Grafting of hydrophobic oligolactide side chains with polymerization degree up to 10 results in chitosan amphiphilic properties. The synthesized chitosan-g-lactide copolymers were used to design 3D scaffolds for tissue engineering such as spherical microparticles and macroporous hydrogels.

  17. Facile preparation of biodegradable chitosan derivative having poly(butylene glycol adipate) side chains.

    PubMed

    Huang, Meifang; Fang, Yue'e

    2006-08-15

    Various modes are being explored for the construction of functional materials from nanoparticles. Despite these efforts, the assembly of nanoparticles remains challenging with respect to the requirement of multiple component organization on varying dimensions and length scales. The graft copolymers of chitosan with poly(butylene glycol adipate) (PBGA) were prepared due to the esterification reaction between PBGA and 6-O-succinate-N-phthaloyl-chitosan (PHCSSA) in the presence of toluene as a swelling agent. The graft copolymers are nanoparticles with the size of few hundred nanometers as observed from TEM. It is a potential method to combine chitosan with the hydrophobic synthetic polymers. The grafting reactions were conducted with various PBGA/PHCSSA feed ratios to obtain chitosan-g-PBGA copolymers with various PBGA contents. FT-IR, NMR, XRD, spectrofluorophotometer, and TEM were detected to characterize the copolymers. Copyright 2006 Wiley Periodicals, Inc.

  18. Daptomycin-loaded polymethylmethacrylate bone cement for joint arthroplasty surgery.

    PubMed

    Hsu, Yuan-Ming; Liao, Chun-Hsing; Wei, Yu-Hong; Fang, Hsu-Wei; Hou, Hsiang-Huan; Chen, Chia-Chun; Chang, Chih-Hung

    2014-06-01

    Antibiotic-loaded acrylic bone cement has been frequently used as an infection prophylaxis or antibiotic-loaded spacer in infected arthroplasty. In addition, daptomycin has been used recently against broad spectrum Gram-positive organisms. The goal of this in vitro study is to investigate the bacteriacidal and mechanical properties of daptomycin-incorporated polymethylmethacrylate (PMMA) bone cement and evaluate its feasibility for clinical use. Daptomycin (0.5, 1, or 2 g) was premixed with 40 g of PMMA bone cement powder before curing. The mechanical properties of the daptomycin-loaded acrylic bone cement (DLABC) were estimated following standard guidance, and the release profile and kinetics of daptomycin from PMMA were analyzed. The antimicrobial efficacy of DLABC was determined with a zone of inhibition (ZOI) assay against Staphylococcus aureus, Staphylococcus epidermis, Enterococcus faecalis, and Enterococcus faecium, respectively. The results showed that the compressive strength, of PMMA bone cement, which was higher than 100 MPa in all groups, was sufficient according to ISO 5833 after incorporation of daptomycin. The encapsulated daptomycin was released for 2 weeks with a 9.59 ± 0.85%, 15.25 ± 0.69%, and 20.64 ± 20.33% released percentage on the first day in the low, mid, and high groups, respectively. According to the calculated release kinetics, incorporated daptomycin should be 3.3 times the original dose to double its release. Although all recipes of DLABC had a microbial inhibitory effect, the effect with a higher encapsulated amount of daptomycin was more significant. Therefore, we believe that daptomycin can be locally delivered from PMMA bone cement at the surgical site as a prophylactic or treatment for osteomyelitis against Gram-positive organisms with intact cement function.

  19. Penile Girth Enhancement With Polymethylmethacrylate-Based Soft Tissue Fillers.

    PubMed

    Casavantes, Luis; Lemperle, Gottfried; Morales, Palmira

    2016-09-01

    An unknown percentage of men will take every risk to develop a larger penis. Thus far, most injectables have caused serious problems. Polymethylmethacrylate (PMMA) microspheres have been injected as a wrinkle filler and volumizer with increasing safety since 1989. To report on a safe and permanently effective method to enhance penile girth and length with an approved dermal filler (ie, PMMA). Since 2007, the senior author has performed penile augmentation in 752 men mainly with Metacrill, a suspension of PMMA microspheres in carboxymethyl-cellulose. The data of 729 patients and 203 completed questionnaires were evaluated statistically. The overall satisfaction rate was 8.7 on a scale of 1 to 10. After one to three injection sessions, average girth increased by 3.5 cm, or 134% (10.2 to 13.7 cm = 134.31%). Penile length also increased by weight and stretching force of the implant from an average of 9.8 to 10.5 cm. Approximately half the patients perceived some irregularities of the implant, which caused no problems. Complications occurred in 0.4%, when PMMA nodules had to be surgically removed in three of the 24% of patients who had a non-circumcised penis. After 5 years of development, penile augmentation with PMMA microspheres appears to be a natural, safe, and permanently effective method. The only complication of nodule formation and other irregularities can be overcome by an improved injection technique and better postimplantation care. Copyright © 2016 International Society for Sexual Medicine. Published by Elsevier Inc. All rights reserved.

  20. Amphiphilic derivatives of chitosan using microwave irradiation. Toward an eco-friendly process to chitosan derivatives.

    PubMed

    Petit, C; Reynaud, S; Desbrieres, J

    2015-02-13

    Conventional heating and microwave irradiation have been compared for the synthesis of chitosans grafted with alkyl chains. Reaction time (1-60 min), temperature (25 and 40 °C) and chitosan molar mass have been studied onto the yield of alkylation. The irradiation mode has been scrupulously controlled to highlight the effect of the use of microwaves. The chemical structure of modified polymers (degree of alkylation) is determined from NMR. In relation to the rheological behavior and surface tension measurements, the evolution of hydrophobic interactions is studied as a function of the yield of alkylation. A maximum of intrinsic viscosity and hydrodynamic diameter was observed for a degree of alkylation of around 10%. All the results tend to prove that microwave assisted synthesis is a powerful method to obtain modified chitosan under extremely low reaction time without any degradation and/or property modifications. Copyright © 2014 Elsevier Ltd. All rights reserved.

  1. A new route for chitosan immobilization onto polyethylene surface.

    PubMed

    Popelka, Anton; Novák, Igor; Lehocký, Marián; Junkar, Ita; Mozetič, Miran; Kleinová, Angela; Janigová, Ivica; Slouf, Miroslav; Bílek, František; Chodák, Ivan

    2012-11-06

    Low-density polyethylene (LDPE) belongs to commodity polymer materials applied in biomedical applications due to its favorable mechanical and chemical properties. The main disadvantage of LDPE in biomedical applications is low resistance to bacterial infections. An antibacterial modification of LDPE appears to be a solution to this problem. In this paper, the chitosan and chitosan/pectin multilayer was immobilized via polyacrylic acid (PAA) brushes grafted on the LDPE surface. The grafting was initiated by a low-temperature plasma treatment of the LDPE surface. Surface and adhesive properties of the samples prepared were investigated by surface analysis techniques. An antibacterial effect was confirmed by inhibition zone measurements of Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). The chitosan treatment of LDPE led to the highest and most clear inhibition zones (35 mm(2) for E. coli and 275 mm(2) for S. aureus). Copyright © 2012 Elsevier Ltd. All rights reserved.

  2. Composite vascular repair grafts via micro-imprinting and electrospinning

    SciTech Connect

    Liu, Yuanyuan Hu, Qingxi; Xiang, Ke Chen, Haiping Li, Yu

    2015-04-15

    Composite vascular grafts formed by micro-imprinting and electrospinning exhibited improved mechanical properties relative to those formed by electrospinning alone. The three-layered composite grafts mimic the three-layered structure of natural blood vessels. The middle layer is made by micro-imprinting poly-p-dioxanone (PPDO), while the inner and outer layers are electrospun mixtures of chitosan and polyvinyl alcohol. The graft morphology is characterized with scanning electron microscopy. For constant graft thicknesses, the PPDO increases the mechanical strength. Cells cultivated on the vascular grafts adhere and proliferate better because of the natural, biological chitosan in the inner and outer layers. Overall, the composite scaffolds could be good candidates for blood vessel repair.

  3. Chitosan and radiation chemistry

    NASA Astrophysics Data System (ADS)

    Chmielewski, Andrzej G.

    2010-03-01

    Chitosan as a raw material with special properties has drawn attention of scientists working in the field of radiation processing and natural polymer products development, and also of specialists working in the field of radiation protection and oncologists. Especially the applications concern reduced molecular weight chitosan which still retain its chemical structure; such form of the compound is fostering biological, physical and chemical reactivity of the product. Chitosan degrades into fragments under γ-ray or electron beam irradiation. Antibacterial properties of the product are applied in manufacturing hydrogel for wound dressing and additional healing properties can be achieved by incorporating in the hydrogel matrix chitosan bonded silver clusters. Another possible application of chitosan is in reducing radiation damage to the radiation workers or radiation cured patients. In the case of radioisotopes oral or respiratory chitosan-based materials can be applied as chelators. Applications of chitosan in oncology are also reported.

  4. Novel procedure to enhance PLA surface properties by chitosan irreversible immobilization

    NASA Astrophysics Data System (ADS)

    Stoleru, Elena; Dumitriu, Raluca Petronela; Munteanu, Bogdanel Silvestru; Zaharescu, Traian; Tănase, Elisabeta Elena; Mitelut, Amalia; Ailiesei, Gabriela-Liliana; Vasile, Cornelia

    2016-03-01

    A novel two step procedure was applied for poly(lactic acid) (PLA) functionalization consisting in the exposure to cold radiofrequency plasma in nitrogen atmosphere or to gamma irradiation followed by ;grafting to; of a chitosan layer using carbodiimide chemistry. The adhesion and stability of the deposited surface layer was assured by plasma/gamma irradiation treatment while the chitosan layer offers antifungal/antibacterial/antioxidant activities. Chitosan with different viscosities/deacetylation degree was deposited by electrospinning or immersion methods. Correlations between rheological behavior of chitosan solutions and chitosan layer deposition conditions are made. The PLA surface properties were investigated by water contact angle measurements, ATR-FTIR spectroscopy, AFM, chemiluminiscence, etc. It has been established that the surface roughness increases direct proportional with cold plasma duration and gamma irradiation dose and further increases by chitosan coating which at its turn depends on chitosan characteristics (viscosity and deacetylation degree) and method of deposition. Nano-fibers with relatively homogeneous and reproducible features are obtained by electrospinning of highly viscous chitosan while with the other two types of chitosan both microparticles and nano-fibers are formed. The chitosan coating obtained by immersion is more homogenous and compact and has a better antibacterial activity than the electrospun layer as fiber meshes.

  5. Hydrophobization and antimicrobial activity of chitosan and paper-based packaging material.

    PubMed

    Bordenave, Nicolas; Grelier, Stephane; Coma, Veronique

    2010-01-11

    This study reports the elaboration of water-resistant, antimicrobial, chitosan and paper-based materials as environmentally friendly food packaging materials. Two types of papers were coated with chitosan-palmitic acid emulsions or with a blend of chitosan and O,O'-dipalmitoylchitosan (DPCT). Micromorphology studies showed that inclusion of hydrophobic compounds into the chitosan matrix was enhanced by grafting them onto chitosan and that this led to their penetration of the paper's core. Compared to chitosan-coated papers, the coating of chitosan-palmitic emulsion kept vapor-barrier properties unchanged (239 and 170 g.m(-2).d(-1) versus 241 and 161 g.m(-2).d(-1)), while the coating of chitosan-DPCT emulsion dramatically deteriorated them (441 and 442 g.m(-2).d(-1)). However, contact angle measurements (110-120 degrees after 1 min) and penetration dynamics analysis showed that both strategies improved liquid-water resistance of the materials. Kit-test showed that all hydrophobized chitosan-coated papers kept good grease barrier properties (degree of resistance 6-8/12). Finally, all chitosan-coated materials exhibited over 98% inhibition on Salmonella Typhimurium and Listeria monocytogenes .

  6. Design and development of multilayer vascular graft

    NASA Astrophysics Data System (ADS)

    Madhavan, Krishna

    2011-07-01

    Vascular graft is a widely-used medical device for the treatment of vascular diseases such as atherosclerosis and aneurysm as well as for the use of vascular access and pediatric shunt, which are major causes of mortality and morbidity in this world. Dysfunction of vascular grafts often occurs, particularly for grafts with diameter less than 6mm, and is associated with the design of graft materials. Mechanical strength, compliance, permeability, endothelialization and availability are issues of most concern for vascular graft materials. To address these issues, we have designed a biodegradable, compliant graft made of hybrid multilayer by combining an intimal equivalent, electrospun heparin-impregnated poly-epsilon-caprolactone nanofibers, with a medial equivalent, a crosslinked collagen-chitosan-based gel scaffold. The intimal equivalent is designed to build mechanical strength and stability suitable for in vivo grafting and to prevent thrombosis. The medial equivalent is designed to serve as a scaffold for the activity of the smooth muscle cells important for vascular healing and regeneration. Our results have shown that genipin is a biocompatible crosslinker to enhance the mechanical properties of collagen-chitosan based scaffolds, and the degradation time and the activity of smooth muscle cells in the scaffold can be modulated by the crosslinking degree. For vascular grafting and regeneration in vivo, an important design parameter of the hybrid multilayer is the interface adhesion between the intimal and medial equivalents. With diametrically opposite affinities to water, delamination of the two layers occurs. Physical or chemical modification techniques were thus used to enhance the adhesion. Microscopic examination and graft-relevant functional characterizations have been performed to evaluate these techniques. Results from characterization of microstructure and functional properties, including burst strength, compliance, water permeability and suture

  7. Novel amphiphilic ternary polysaccharide derivates chitosan-g-PCL-b-MPEG: synthesis, characterization, and aggregation in aqueous solution.

    PubMed

    Lu, Yiye; Liu, Li; Guo, Shengrong

    Chitosan-g-PCL-b-MPEG copolymers of various compositions were successful synthesized via a protection-graft-deprotection procedure, by the esterification of phthaloyl-protected chitosan (PHCS) with MPEG-b-PCL-COOH, which was synthesized from MPEG and epsilon-caprolactone and carboxylated by maleic anhydride. The chemical structure of the chitosan-g-PCL-b-MPEG was characterized by Fourier transform infrared and NMR spectroscopy. The chitosan-g-PCL-b-MPEG was obtained as amphoteric hybrid with amino polysaccharide backbone and amphiphilic MPEG-b-PCL side chain. Their crystallinity and aggregation behavior in aqueous solution were also investigated.

  8. Bone grafts.

    PubMed

    Hubble, Matthew J W

    2002-09-01

    Bone grafts are used in musculoskeletal surgery to restore structural integrity and enhance osteogenic potential. The demand for bone graft for skeletal reconstruction in bone tumor, revision arthroplasty, and trauma surgery, couple with recent advances in understanding and application of the biology of bone transplantation, has resulted in an exponential increase in the number of bone-grafting procedures performed over the last decade. It is estimated that 1.5 million bone-grafting procedures are currently performed worldwide each year, compared to a fraction of that number 20 years ago. Major developments also have resulted in the harvesting, storage, and use of bone grafts and production of graft derivatives, substitutes, and bone-inducing agents.

  9. Gentamicin modified chitosan film with improved antibacterial property and cell biocompatibility.

    PubMed

    Liu, Yang; Ji, Peihong; Lv, Huilin; Qin, Yong; Deng, Linhong

    2017-05-01

    Gentamicin modified chitosan film (CS-GT) was produced using a three-step procedure comprising: (i) the chitosan solution was air-dried to form a chitosan (CS) film, (ii) using citric acid to generate the amide and carboxyl groups on the surface of CS, (iii) the CS with surface carboxyl groups was modified by grafting of gentamicin. After modification, this CS-GT film has excellent hydrophilicity and biocompatibility. It is very evident that the gentamicin grafting treatment significantly improves the antibacterial properties of the CS film. Our preliminary results suggest that this novel gentamicin modified chitosan film, which can be prepared in large quantities and at low cost, should have potential application in biomedical applications. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. Outer electrospun polycaprolactone shell induces massive foreign body reaction and impairs axonal regeneration through 3D multichannel chitosan nerve guides.

    PubMed

    Duda, Sven; Dreyer, Lutz; Behrens, Peter; Wienecke, Soenke; Chakradeo, Tanmay; Glasmacher, Birgit; Haastert-Talini, Kirsten

    2014-01-01

    We report on the performance of composite nerve grafts with an inner 3D multichannel porous chitosan core and an outer electrospun polycaprolactone shell. The inner chitosan core provided multiple guidance channels for regrowing axons. To analyze the in vivo properties of the bare chitosan cores, we separately implanted them into an epineural sheath. The effects of both graft types on structural and functional regeneration across a 10 mm rat sciatic nerve gap were compared to autologous nerve transplantation (ANT). The mechanical biomaterial properties and the immunological impact of the grafts were assessed with histological techniques before and after transplantation in vivo. Furthermore during a 13-week examination period functional tests and electrophysiological recordings were performed and supplemented by nerve morphometry. The sheathing of the chitosan core with a polycaprolactone shell induced massive foreign body reaction and impairment of nerve regeneration. Although the isolated novel chitosan core did allow regeneration of axons in a similar size distribution as the ANT, the ANT was superior in terms of functional regeneration. We conclude that an outer polycaprolactone shell should not be used for the purpose of bioartificial nerve grafting, while 3D multichannel porous chitosan cores could be candidate scaffolds for structured nerve grafts.

  11. Single crystals of chitosan.

    PubMed

    Cartier, N; Domard, A; Chanzy, H

    1990-10-01

    Lamellar single crystals of chitosan were prepared at 125 degrees C by adding ammonia to a low DP fraction of chitosan dissolved in water. The crystals gave sharp electron diffraction diagrams which could be indexed in an orthorhombic P2(1)2(1)2(1) unit cell with a = 8.07 A, b = 8.44 A, c = 10.34 A. The unit cell contained two anti-parallel chitosan chains and no water molecules. It was found that cellulose microfibrils from Valonia ventricosa could act as nuclei for inducing the crystallization of chitosan on cellulose. This produced a shish-kebab morphology.

  12. Synthesis, characterization and application of acryloyl chitosan anchored copolymer towards algae flocculation.

    PubMed

    M, Dharani; S, Balasubramanian

    2016-11-05

    A novel water soluble flocculant AC-g-P(DMC-MACPPC) was synthesized by free radical polymerization of [2-(methacryloyloxy) ethyl] trimethylammonium chloride (DMC) and 4-methacryloyl 1-cyclopentyl piperazinium chloride (MACPPC), grafted on to acryloyl chitosan (AC). The grafting of copolymer was confirmed by DRS-UV, FTIR, NMR, Raman, XRD and XPS spectral techniques. The AC-g-P(DMC-MACPPC) exhibits higher flocculation efficiency towards harvesting of C. vulgaris micro algae, when compared to that of copolymer P(DMC-MACPPC) and homo polymer PMACPPC. The higher efficiency exhibited by the grafted copolymer can be attributed to the increase in positive charge and molecular weight after grafting on to acryloyl chitosan. The grafted copolymer AC-g-P(DMC-MACPPC) is very easy to synthesize, economical and water soluble which makes it a promising flocculant in the algae harvesting process.

  13. Chitosan composites for bone tissue engineering--an overview.

    PubMed

    Venkatesan, Jayachandran; Kim, Se-Kwon

    2010-08-02

    Bone contains considerable amounts of minerals and proteins. Hydroxyapatite [Ca₁₀(PO₄)₆(OH)₂] is one of the most stable forms of calcium phosphate and it occurs in bones as major component (60 to 65%), along with other materials including collagen, chondroitin sulfate, keratin sulfate and lipids. In recent years, significant progress has been made in organ transplantation, surgical reconstruction and the use of artificial prostheses to treat the loss or failure of an organ or bone tissue. Chitosan has played a major role in bone tissue engineering over the last two decades, being a natural polymer obtained from chitin, which forms a major component of crustacean exoskeleton. In recent years, considerable attention has been given to chitosan composite materials and their applications in the field of bone tissue engineering due to its minimal foreign body reactions, an intrinsic antibacterial nature, biocompatibility, biodegradability, and the ability to be molded into various geometries and forms such as porous structures, suitable for cell ingrowth and osteoconduction. The composite of chitosan including hydroxyapatite is very popular because of the biodegradability and biocompatibility in nature. Recently, grafted chitosan natural polymer with carbon nanotubes has been incorporated to increase the mechanical strength of these composites. Chitosan composites are thus emerging as potential materials for artificial bone and bone regeneration in tissue engineering. Herein, the preparation, mechanical properties, chemical interactions and in vitro activity of chitosan composites for bone tissue engineering will be discussed.

  14. Polyphenol-chitosan conjugates: Synthesis, characterization, and applications.

    PubMed

    Hu, Qiaobin; Luo, Yangchao

    2016-10-20

    Chitosan, the only positively charged polysaccharide in the world, is very attractive for food, medicinal and pharmaceutical applications because of its promising properties, including non-toxicity, superb biodegradability, high biocompatibility, abundant availability and low cost. In order to overcome the poor water solubility and widen the applications of chitosan, various polyphenol-chitosan conjugates have been synthesized in recent years. The present review focuses on the chitosan-based conjugates formed using different polyphenols, including gallic acid, caffeic acid, ferulic acid, salicylic acid, catechin, and EGGE, etc. Three major synthesis techniques, namely, activated ester-mediated modification, enzyme-mediated strategy, and free radical induced grafting approach are introduced in detail. In addition, the new physicochemical and biological properties of polyphenol-chitosan conjugates are introduced, including water solubility, thermo stability, in vitro and in vivo antioxidant activity, antimicrobial and anticancer activity. Furthermore, the novel applications of each conjugate are discussed in detail. Lastly, the challenges and prospective areas of study related to polyphenol-chitosan are summarized.

  15. The Use of chitosan in The Formation of Silver Nanoparticles, Chitosanic Nanoparticles and Fibrous Structures

    NASA Astrophysics Data System (ADS)

    Abdelgawad, Abdelrahman Mohamed

    Nanoscale materials have attracted much attention in the last two decades due to their unique properties. The size effect attains new chemical and physical properties to these materials. Nanoparticles and nanofiber are major component of nanomaterials and they have heavily investigated in the literature for different applications. Nanoparticles could be produced from both metals as well as polymers. Chitosan, which is a natural polymer, can be used as capping agent in the preparation of metallic nanoparticles and itself, can produce nanoparticles. The utilization of nanoparticles and nanofibers for wound dressing materials is a very popular approach. Acquiring antibacterial properties to the wound dressing materials could be obtained either by formulation of nanomaterials composites or direct chemical modification of the substance. To improve the antibacterial properties of chitosan two approaches were applied. First, is through the formulation of chitosan with silver nanoparticles and the formation of nanofiber mats. In this study, the concepts of green chemistry were applied and silver nanoparticles were prepared in high concentration using chitosan as a capping polymer and glucose as a reducing agent. Nanofiber mats of polyvinyl alcohol/chitosan/silvernanoparticles were produced via electrospinning. The antibacterial activity of these fibers shows bactericidal effect against E. coli at low concentrations of Ag-NPs. In the second approach, direct chemical modification of chitosan was performed by grafting of Iodoacetic acid to the amino group at carbon-2. The chemical structure of chitosan Iodoacetamide derivative (CIA) was confirmed by FTIR and H1-NMR. The derivative was amorphous and water soluble at neutral pH. The minimum inhibitory concentration of CIA, against E. coli, was 400ig/mL and the derivative was bacteriostatic after 4h of treatment. Nanofiber mats of polyvinyl alcohol/chitosan/chitosan Iodoacetamide were produced via electrospinning. The

  16. Synthesis and characterization of chitosan based dye containing quaternary ammonium group.

    PubMed

    Tang, Ruilin; Zhang, Ying; Zhang, Yang; Yu, Zhiming

    2016-03-30

    A new antimicrobial biopolymer dye was synthesized by reaction of quaternary ammonium salt of chitosan and reactive red x-3b. And quaternary ammonium salt of chitosan was produced by grafting glycidyltrimethylammonium chloride on chitosan. The synthesized materials were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), solubility test and antimicrobial test. Results show that the antimicrobial biopolymer dye was combined by N(+)(CH3)3 of quaternary ammonium salt of chitosan and sulfonic group of reactive red x-3b. Water solubility of chitosan biopolymer dye was increased as well as pH value. In addition, antibacterial property of new synthesized dye was excellent, whose antibacterial rates of Staphylococcus and Escherichia coli were both bigger than 99%. These results may provide new perspectives on improving the decorative properties and antimicrobial properties in wood industry.

  17. Preparation of crosslinked carboxymethyl chitosan with epichlorohydrin and its use for Pb(II) removal

    NASA Astrophysics Data System (ADS)

    Hastuti, Budi; Mudasir, Siswanta, Dwi; Triyono

    2015-12-01

    A modified pectin has been synthesized by reacting/combining -OH group among pectin and chitosan with ECH (Epichlorohydrin) croslinker agent. Chitosan was grafted with acetate to form carboxymetyl chitosan (CMC). The result of this study was Pectin-CMC-ECH film could be greater adsorp Pb(II) ion than chitosan without modified. The structure of Pectin-CMC-ECH film was characterized by Fourier transform infrared (FTIR) spectroscopy. Adsorption experiment were performed in batch processes; Result of the study showed that optimum conditions for the adsorption of Pb(II) on the adsorbent were found at pH 5 with with 93 % of adsorption and adsorption capacity was 42.77 mg/g, contact time 12 hour with 91 % of adsorption and adsorption capacity was 39.74 mg/g. Pectin-CMC-ECH film demonstrate the ability to absorb Pb (II) metal ions was higher than chitosan without modified.

  18. Sulfonated chitosan and dopamine based coatings for metallic implants in contact with blood.

    PubMed

    Campelo, Clayton S; Chevallier, Pascale; Vaz, Juliana M; Vieira, Rodrigo S; Mantovani, Diego

    2017-03-01

    Thrombosis and calcification constitute the main clinical problems when blood-interacting devices are implanted in the body. Coatings with thin polymer layers represent an acknowledged strategy to modulate interactions between the material surface and the blood environment. To ensure the implant success, at short-term the coating should limit platelets adhesion and delay the clot formation, and at long-term it should delay the calcification process. Sulfonated chitosan, if compared to native chitosan, shows the unique ability to reduce proteins adsorption, decrease thrombogenic properties and limit calcification. In this work, stainless steel surfaces, commonly used for cardiovascular applications, were coated with sulfonated chitosan, by using dopamine and PEG as anchors, and the effect of these grafted surfaces on platelet adhesion, clot formation as well as on calcification were investigated. Surface characterization techniques evidenced that the coating formation was successful, and the sulfonated chitosan grafted sample exhibited a higher roughness and hydrophilicity, if compared to native chitosan one. Moreover, sulfonated surface limited platelet activation and the process of clot formation, thus confirming its high biological performances in blood. Calcium deposits were also lower on the sulfonated chitosan sample compared to the chitosan one, thus showing that calcification was minimal in presence of sulfonate groups. In conclusion, this sulfonated-modified surface has potential to be as blood-interacting material. Copyright © 2016. Published by Elsevier B.V.

  19. Polymethylmethacrylate-assisted ventral discectomy: Rate of pseudarthrosis and clinical outcome with a minimum follow-up of 5 years

    PubMed Central

    2011-01-01

    Background Polymethylmethacrylate (PMMA) assisted ventral discectomy has been criticized for high rates of graft migration and pseudarthrosis when compared with various other fusion procedures for the treatment of cervical degenerative disc disease (DDD), therefore rendering it not the preferred choice of treatment today. Recently however spine surgery has been developing towards preservation rather than restriction of motion, indicating that fusion might not be necessary for clinical success. This study presents a long term comparison of clinical and radiological data from patients with pseudarthrosis and solid arthrodesis after PMMA assisted ventral discectomy was performed. Methods From 1986 to 2004 416 patients underwent ventral discectomy and PMMA interposition for DDD. The clinical and radiological outcome was assessed for 50 of 127 eligible patients after a mean of 8.1 years. Based on postoperative radiographs the patients were dichotomized in those with a pseudarthrosis (group A) and those with solid arthrodesis (group B). Results Pseudarthrosis with movement of more than 2 of the operated segment was noted in 17 cases (group A). In 33 cases no movement of the vertebral segment could be detected (group B). The analysis of the clinical data assessed through the neck disability index (NDI), the visual analogue scale (VAS) of neck and arm pain and Odom's criteria did not show any significant differences between the groups. Patients from group B showed a trend to higher adjacent segment degeneration (ASD) than group A (p = 0.06). This correlated with the age of the patients. Conclusions PMMA assisted discectomy shows a high rate of pseudarthrosis. But the clinical long-term success does not seem to be negatively affected by this. PMID:21711527

  20. Polymethylmethacrylate-assisted ventral discectomy: rate of pseudarthrosis and clinical outcome with a minimum follow-up of 5 years.

    PubMed

    Cabraja, Mario; Koeppen, Daniel; Lanksch, Wolfgang R; Maier-Hauff, Klaus; Kroppenstedt, Stefan

    2011-06-28

    Polymethylmethacrylate (PMMA) assisted ventral discectomy has been criticized for high rates of graft migration and pseudarthrosis when compared with various other fusion procedures for the treatment of cervical degenerative disc disease (DDD), therefore rendering it not the preferred choice of treatment today. Recently however spine surgery has been developing towards preservation rather than restriction of motion, indicating that fusion might not be necessary for clinical success. This study presents a long term comparison of clinical and radiological data from patients with pseudarthrosis and solid arthrodesis after PMMA assisted ventral discectomy was performed. From 1986 to 2004 416 patients underwent ventral discectomy and PMMA interposition for DDD. The clinical and radiological outcome was assessed for 50 of 127 eligible patients after a mean of 8.1 years. Based on postoperative radiographs the patients were dichotomized in those with a pseudarthrosis (group A) and those with solid arthrodesis (group B). Pseudarthrosis with movement of more than 2 of the operated segment was noted in 17 cases (group A). In 33 cases no movement of the vertebral segment could be detected (group B). The analysis of the clinical data assessed through the neck disability index (NDI), the visual analogue scale (VAS) of neck and arm pain and Odom's criteria did not show any significant differences between the groups.Patients from group B showed a trend to higher adjacent segment degeneration (ASD) than group A (p = 0.06). This correlated with the age of the patients. PMMA assisted discectomy shows a high rate of pseudarthrosis. But the clinical long-term success does not seem to be negatively affected by this.

  1. Use of a CD laser pickup head to fabricate microelectrodes in polymethylmethacrylate substrates for biosensing applications.

    PubMed

    López-Aparicio, Jehú; Hautefeuille, Mathieu; Herrera-Domínguez, Sara; Razo-de-León, Adriana; Cano-Jorge, Mariel; Rojas-Benito, Ixchetl; Centeno-Sierra, Mariana; Fiordelisio-Coll, Tatiana; Stern-Forgach, Catalina Elizabeth

    2017-03-01

    In this work, we report a simple fabrication method for microelectrodes on a polymethylmethacrylate substrate, using a low-cost laser platform based on a CD-DVD unit for direct rapid-prototyping. We used this laser microfabrication technique to etch any desired design on polymethylmethacrylate substrates to produce microchannels with controlled geometry, with a highly repeatable micron-scale resolution. Those shallow microchannels were then filled with a conductive paste of material of our choice that was converted into microelectrodes of desired shapes and geometries after drying. To validate our process, different geometries, sizes and materials were used as electrodes, and then tested for amperometry and impedance measurements. Development of these microelectrodes is motivated by their potential application in sensors and biosensors, such as glucose and cell counting, as demonstrated in this paper.

  2. Preparation and characterization of Ag-cluster in poly(methylmethacrylate)

    SciTech Connect

    Yanagihara, Naohisa; Ishii, Yoshitaka; Kawase, Takanori; Kaneko, Toshimare; Horie, Hisashi; Hara, Toru

    1997-09-01

    Solid sols of silver in poly(methylmethacrylate), Ag/PMMA, were prepared by bulk polymerization of methyl methacrylate (MMA) with benzoyl peroxide (BPO) as an initiator in the presence of silver(I) trifluoroacetate. Ag/PMMAs were characterized by visible spectroscopy. Effects of the concentration of initiator, the concentration of silver(I) complex and the heat-treatment time on the formation of silver cluster were studied in detail.

  3. Efficacy of Antibiotic-Impregnated Polymethylmethacrylate Beads in a Rhesus Macaque (Macaca mulatta) with Osteomyelitis

    PubMed Central

    Kelly, Kristi R; Kapatkin, Amy R; Zwingenberger, Allison L; Christe, Kari L

    2012-01-01

    Here we describe the successful surgical implementation of antibiotic-impregnated polymethylmethacrylate beads in a rhesus macaque (Macaca mulatta) with marked osteomyelitis. The macaque presented to the veterinary clinic with grossly contaminated bite wounds in the left ankle secondary to conspecific trauma. Radiographic findings were highly suggestive of osteomyelitis. Additional differential diagnoses included bony infarct, fracture, and cellulitis. In light of the location of the lesion and extensive tissue trauma, the animal had a poor prognosis. Systemic, broad-spectrum antibiotics were instituted. After 2 wk of care, lesions did not respond to empirical therapies. On consultation, a veterinary orthopedic surgeon at another facility recommended placement of antibiotic-impregnated polymethylmethacrylate beads at the sites of osteomyelitis. The animal underwent minor surgery in which beads were introduced into the wound. The monkey had a positive response to therapy. The animal regained full function and was returned to outdoor social housing. Veterinarians are encouraged to consider using antibiotic-impregnated polymethylmethacrylate beads when treating osteomyelitis in other nonhuman primates and in other traditional laboratory animal species. PMID:23043785

  4. Efficacy of antibiotic-impregnated polymethylmethacrylate beads in a rhesus macaque (Macaca mulatta) with osteomyelitis.

    PubMed

    Kelly, Kristi R; Kapatkin, Amy R; Zwingenberger, Allison L; Christe, Kari L

    2012-08-01

    Here we describe the successful surgical implementation of antibiotic-impregnated polymethylmethacrylate beads in a rhesus macaque (Macaca mulatta) with marked osteomyelitis. The macaque presented to the veterinary clinic with grossly contaminated bite wounds in the left ankle secondary to conspecific trauma. Radiographic findings were highly suggestive of osteomyelitis. Additional differential diagnoses included bony infarct, fracture, and cellulitis. In light of the location of the lesion and extensive tissue trauma, the animal had a poor prognosis. Systemic, broad-spectrum antibiotics were instituted. After 2 wk of care, lesions did not respond to empirical therapies. On consultation, a veterinary orthopedic surgeon at another facility recommended placement of antibiotic-impregnated polymethylmethacrylate beads at the sites of osteomyelitis. The animal underwent minor surgery in which beads were introduced into the wound. The monkey had a positive response to therapy. The animal regained full function and was returned to outdoor social housing. Veterinarians are encouraged to consider using antibiotic-impregnated polymethylmethacrylate beads when treating osteomyelitis in other nonhuman primates and in other traditional laboratory animal species.

  5. Carboxymethyl chitosan-poly(amidoamine) dendrimer core-shell nanoparticles for intracellular lysozyme delivery.

    PubMed

    Zhang, Xiaoyang; Zhao, Jun; Wen, Yan; Zhu, Chuanshun; Yang, Jun; Yao, Fanglian

    2013-11-06

    Intracellular delivery of native, active proteins is challenging due to the fragility of most proteins. Herein, a novel polymer/protein polyion complex (PIC) nanoparticle with core-shell structure was prepared. Carboxymethyl chitosan-grafted-terminal carboxyl group-poly(amidoamine) (CM-chitosan-PAMAM) dendrimers were synthesized by amidation and saponification reactions. (1)H NMR was used to characterize CM-chitosan-PAMAM dendrimers. The TEM images and results of lysozyme loading efficiency indicated that CM-chitosan-PAMAM dendrimers could self-assemble into core-shell nanoparticles, and lysozyme was efficiently encapsulated inside the core of CM-chitosan-PAMAM dendrimer nanoparticles. Activity of lysozyme was completely inhibited by CM-chitosan-PAMAM Dendrimers at physiological pH, whereas it was released into the medium and exhibited a significant enzymatic activity in an acidic intracellular environment. Moreover, the CM-chitosan-PAMAM dendrimer nanoparticles did not exhibit significant cytotoxicity in the range of concentrations below 3.16 mg/ml. The results indicated that these CM-chitosan-PAMAM dendrimers have excellent properties as highly potent and non-toxic intracellular protein carriers, which would create opportunities for novel applications in protein delivery.

  6. Preparation of methacrylamide-functionalized crosslinked chitosan by free radical polymerization for the removal of lead ions.

    PubMed

    Sutirman, Zetty Azalea; Sanagi, Mohd Marsin; Abd Karim, Khairil Juhanni; Wan Ibrahim, Wan Aini

    2016-10-20

    A new poly(methacrylamide) grafted crosslinked chitosan was prepared for removal of lead, Pb(II) ion from aqueous solution. Crosslinked chitosan, in beads form, was grafted with methacrylamide (MAm) using ammonium persulfate (APS) as free radical initiator. Evidence of grafting was determined by comparing FTIR, TGA, SEM and (13)C NMR analyses of chitosan and graft copolymer. The optimal conditions for grafting reaction were as follow: crosslinked chitosan beads (1g), MAm (17.62×10(-1)M), APS (2.63×10(-1)M), reaction time (3h) and temperature (60°C). The modified chitosan bead was then used in laboratory batch experiments to evaluate the removal of Pb(II) ion from water samples. The Langmuir and Freundlich adsorption models were also applied to describe the equilibrium isotherms. The results revealed that the adsorption of Pb(II) ions onto the beads fitted very well with the Langmuir model with the maximum capacity (qmax) of 250mgg(-1).

  7. High-Voltage Poling of a Bulk Sample of Disperse Red 1 Polymethylmethacrylate Guest-Host Polymer for U.S. Army Electro-Optical Applications

    DTIC Science & Technology

    2009-07-01

    High-Voltage Poling of a Bulk Sample of Disperse Red 1 Polymethylmethacrylate Guest-Host Polymer for U.S. Army Electro-Optical Applications...High-Voltage Poling of a Bulk Sample of Disperse Red 1 Polymethylmethacrylate Guest-Host Polymer for U.S. Army Electro-Optical Applications...January 2007–November 2008 4. title and subtitle High-Voltage Poling of a Bulk Sample of Disperse Red 1 Polymethylmethacrylate Guest-Host Polymer for

  8. High-Voltage Poling of a Bulk Sample of Disperse Red 1 Polymethylmethacrylate Guest-Host Polymer for U.S. Army Electro-optical Applications

    DTIC Science & Technology

    2008-12-01

    Poling Of A Bulk Sample Of Disperse Red 1 Polymethylmethacrylate Guest-Host Polymer For U.S. Army Electrooptical Applications 5a. CONTRACT NUMBER...explanations / continuatLons / OPSEC review comments Block A-2 ... Polymethylmethacrylate Guest-Host Polymer for U.S. Army Electro-Optical Applications Block...VOLTAGE POLING OF A BULK SAMPLE OF DISPERSE RED 1 POLYMETHYLMETHACRYLATE GUEST-HOST POLYMER FOR U.S. ARMY ELECTRO- OPTICAL APPLICATIONS Robert H

  9. [Chitosan in topical preparations].

    PubMed

    Matusová, D; Truplová, E

    2007-06-01

    Chitosan in topical preparations Within the framework of experimental work at the Department of Pharmaceutical Technology of Slovak Medical University, "insect" chitin obtained from the buff-tailed bumblebee (Bombus terrestris) was processed to produce dosage forms and compared with commercially available chitin, or chitosan, obtained from shrimps (Pandalus borealus). The paper aimed to find whether insect chitin, or chitosan, possessed similar technological properties as commercially available and for topical preparations used products. Samples were prepared containing chitin, or chitosan, of different origin, 0.25 and 0.5% in a gel base. In some gels the gel base was acidified with citric acid (in an amount of 0.75%) or lactic acid (1%) to improve the mechanical properties of foils. All samples were well applicable and after drying a relatively resistant transparent layer was formed on the skin. All samples could be made to produce elastic foils, which after moistening clung well to the skin. Both chitin and chitosan obtained from the bodies of buff-tailed bumblebees differed from reference materials obtained from shrimps by the degree of deacetylation, possessed different technological properties, e.g., finer fibres, were more fragile, and when wet, they could be disintegrated better, which is obvious also from the results of microscopic evaluation. Chitosan prepared from chitin SAV (insect) possessed substantially finer particles in the dosage form. The evaluation of the flow properties of the prepared samples revealed that except Sample I (gel base alone) they are time-dependent tixotropic systems. Whereas chitin gels did not show any antimicrobial effect (which is apparently connected with bad solubility of chitin), gels with chitosan showed this activity. A more marked effect was observed in the strains of Staphylococcus aureus and Pseudomonas aeruginosa, and in Escherichia coli it was weaker. The paper reports the first tentative results of comparisons of

  10. Use of novel chitosan hydrogels for chemical tissue bonding of autologous chondral transplants.

    PubMed

    Gittens, Jamila; Haleem, Amgad M; Grenier, Stephanie; Smyth, Niall A; Hannon, Charles P; Ross, Keir A; Torzilli, Peter A; Kennedy, John G

    2016-07-01

    The objective of this study was to evaluate the effect of chemical tissue bonding (CTB) on adhesion strength, fluid permeability, and cell viability across a cartilaginous graft-host interface in an in vitro autologous chondral transplant (ACT) model. Chitosan-based cross-linkers; Chitosan-Rose Bengal [Chi-RB (Ch-ABC)], Chitosan-Genipin [Chi-GP (Ch-ABC)], and Chitosan-Rose Bengal-Genipin [Chi-RB-GP (Ch-ABC)] were applied to bovine immature cartilage explants after pre-treatment with surface degrading enzyme, Chondroitinase-ABC (Ch-ABC). Adhesion strength, fluid permeability and cell viability were assessed via mechanical push-out shear testing, fluid transport and live/dead cell staining, respectively. All three chitosan-based cross-linkers significantly increased the adhesion strength at the graft-host interface, however, only a statistically significant decrease in fluid permeability was noted in Chi-GP (Ch-ABC) specimen compared to untreated controls. Cell viability was maintained for 7 days of culture across all three treatment groups. These results show the potential clinical relevance of novel chitosan-based hydrogels in enhancing tissue integration and reducing synovial fluid penetration after ACT procedures in diarthoidal joints such as the knee and ankle. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:1139-1146, 2016. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

  11. Investigation of Self-Assembly Processes for Chitosan-Based Coagulant-Flocculant Systems: A Mini-Review

    PubMed Central

    Bhalkaran, Savi; Wilson, Lee D.

    2016-01-01

    The presence of contaminants in wastewater poses significant challenges to water treatment processes and environmental remediation. The use of coagulation-flocculation represents a facile and efficient way of removing charged particles from water. The formation of stable colloidal flocs is necessary for floc aggregation and, hence, their subsequent removal. Aggregation occurs when these flocs form extended networks through the self-assembly of polyelectrolytes, such as the amine-based polysaccharide (chitosan), which form polymer “bridges” in a floc network. The aim of this overview is to evaluate how the self-assembly process of chitosan and its derivatives is influenced by factors related to the morphology of chitosan (flocculant) and the role of the solution conditions in the flocculation properties of chitosan and its modified forms. Chitosan has been used alone or in conjunction with a salt, such as aluminum sulphate, as an aid for the removal of various waterborne contaminants. Modified chitosan relates to grafted anionic or cationic groups onto the C-6 hydroxyl group or the amine group at C-2 on the glucosamine monomer of chitosan. By varying the parameters, such as molecular weight and the degree of deacetylation of chitosan, pH, reaction and settling time, dosage and temperature, self-assembly can be further investigated. This mini-review places an emphasis on the molecular-level details of the flocculation and the self-assembly processes for the marine-based biopolymer, chitosan. PMID:27706052

  12. Investigation of Self-Assembly Processes for Chitosan-Based Coagulant-Flocculant Systems: A Mini-Review.

    PubMed

    Bhalkaran, Savi; Wilson, Lee D

    2016-09-30

    The presence of contaminants in wastewater poses significant challenges to water treatment processes and environmental remediation. The use of coagulation-flocculation represents a facile and efficient way of removing charged particles from water. The formation of stable colloidal flocs is necessary for floc aggregation and, hence, their subsequent removal. Aggregation occurs when these flocs form extended networks through the self-assembly of polyelectrolytes, such as the amine-based polysaccharide (chitosan), which form polymer "bridges" in a floc network. The aim of this overview is to evaluate how the self-assembly process of chitosan and its derivatives is influenced by factors related to the morphology of chitosan (flocculant) and the role of the solution conditions in the flocculation properties of chitosan and its modified forms. Chitosan has been used alone or in conjunction with a salt, such as aluminum sulphate, as an aid for the removal of various waterborne contaminants. Modified chitosan relates to grafted anionic or cationic groups onto the C-6 hydroxyl group or the amine group at C-2 on the glucosamine monomer of chitosan. By varying the parameters, such as molecular weight and the degree of deacetylation of chitosan, pH, reaction and settling time, dosage and temperature, self-assembly can be further investigated. This mini-review places an emphasis on the molecular-level details of the flocculation and the self-assembly processes for the marine-based biopolymer, chitosan.

  13. Influence of amine-grafted multi-walled carbon nanotubes on physical and rheological properties of PMMA-based nanocomposites

    SciTech Connect

    Kim, Ki-Seok; Park, Soo-Jin

    2011-11-15

    In this work, poly(methyl methacrylate) (PMMA) was grafted onto amine treated multi-walled carbon nanotubes (NH-MWNTs) and the physical and rheological properties of the NH-MWNTs-g-PMMA nanocomposites were investigated. The graft reaction of NH-MWNTs and the PMMA matrix was confirmed from the change of the N{sub 1S} peaks, including those of amine oxygen and amide oxygen, by X-ray photoelectron spectroscopy (XPS). The thermal and mechanical properties of the NH-MWNT-g-PMMA nanocomposites were enhanced by the graft reaction between NH-MWNTs and PMMA matrix. In addition, the viscosity of the nanocomposites was increased with the addition of NH-MWNTs. Storage (G') and loss modulus (G'') were significantly increased by increase in the NH-MWNT content compared to acid-treated MWNTs/PMMA nanocomposites. This increase was attributed to the strong interaction by the grafting reaction between NH-MWNTs and the PMMA matrix. - Graphical abstract: This describes the increase of mechanical properties in NH-MWNTs-g-PMMA hybrid composites with different NH-MWNT contents. Highlights: > Aminized carbon nanotubes are used as reinforcement for poly(methylmethacrylate). > Poly(methylmethacrylate) is grafted on aminized carbon nanotubes by thermal reaction. > Grafting of carbon nanotubes and polymer provide enhanced physical properties. > It was due to the strong interaction between carbon nanotubes and polymer matrix.

  14. Biodegradability and swelling capacity of kaolin based chitosan-g-PHEMA nanocomposite hydrogel.

    PubMed

    Pradhan, Arun Kumar; Rana, Pradeep Kumar; Sahoo, Prafulla Kumar

    2015-03-01

    Chitosan, a natural biopolymer, obtained by alkaline deacetylation of chitin, exhibits excellent biological properties such as biodegradability, immunological and antibacterial activity. Recently, there has been a growing interest in the chemical modification of chitosan in order to widen its applications. The chemical modification of chitosan has been achieved via grafting of monomer, 2-hydroxyethyl methacrylate (HEMA) in the presence of the initiator, ammonium persulfate (APS) and kaolin was added to improve the mechanical strength of the newly developed nanocomposites hydrogel. The so prepared grafted nanocomposites hydrogel was characterized by FTIR, XRD, SEM, TEM and TGA. The equilibrium water content (EWC) of the samples were measured at different pH ranges 6.5-8.0 and found optimum at pH 7.5 for biomedical applications. Further, the biodegradability of the samples was studied at different time intervals from 15 days to 1 year but, the kaolin based nanohydrogels exhibited good biodegradability.

  15. Chitosan hydrogel improves mesenchymal stem cell transplant survival and cardiac function following myocardial infarction in rats

    PubMed Central

    Xu, Bin; Li, Yang; Deng, Bo; Liu, Xiaojing; Wang, Lin; Zhu, Qing-Lei

    2017-01-01

    Myocardial infarction (MI) remains the leading cause of cardiovascular-associated mortality and morbidity. Improving the retention rate, survival and cardiomyocyte differentiation of mesenchymal stem cells (MSCs) is important in improving the treatment of patients with MI. In the present study, temperature-responsive chitosan hydrogel, an injectable scaffold, was used to deliver MSCs directly into the infarcted myocardium of rats following MI. Histopathology and immunohistochemical staining were used to evaluate cardiac cell survival and regeneration, and cardiac function was assessed using an echocardiograph. It was demonstrated that chitosan hydrogel increased graft size and cell retention in the ischemic heart, promoted MSCs to differentiate into cardiomyocytes and increased the effects of MSCs on neovasculature formation. Furthermore, chitosan hydrogel enhanced the effect of MSCs on the improvement of cardiac function and hemodynamics in the infarcted area of rats following MI. These findings suggest that chitosan hydrogel is an appropriate material to deliver MSCs into infarcted myocardium. PMID:28352335

  16. Novel Anti-infective Activities of Chitosan Immobilized Titanium Surface with Enhanced Osteogenic Properties

    PubMed Central

    Ghimire, Niranjan; Luo, Jie; Tang, Ruogu; Sun, Yuyu; Deng, Ying

    2014-01-01

    We have covalently immobilized chitosan onto a titanium (Ti) surface to manage implant-related infection and poor osseointegration, two of the major complications of orthopedic implants. The Ti surface was first treated with sulfuric acid (SA) and then covalently grafted with chitosan. Surface roughness, contact angle and surface zeta potential of the samples were markedly increased by the sulfuric acid treatment and the subsequent chitosan immobilization. The chitosan-immobilized Ti (SA-CS-Ti) showed two novel antimicrobial roles: it a) prevented the invasion and internalization of bacteria into the osteoblast-like cells, and b) significantly increased the susceptibility of adherent bacteria to antibiotics. In addition, the sulfuric acid-treated Ti (SA-Ti) and SA-CS-Ti led to significantly increased (P<0.05) osteoblast-like cell attachment, enhanced cell proliferation, and better osteogenic differentiation and mineralization of osteoblast-like cells. PMID:25033432

  17. Effect of calcium sulphate nanorods on mechanical properties of chitosan-hydroxyethyl methacrylate (HEMA) copolymer nanocomposites.

    PubMed

    Bari, Sarang S; Mishra, Satyendra

    2017-02-10

    Copolymers of chitosan and hydroxyetheyl methacrylate (HEMA) were successfully synthesized using ceric ammonium nitrate (CAN) as an initiator, via in situ polymerization method, followed by efficacious preparation of their nanocomposites by incorporating calcium sulphate nanorods via solution blending process. Hydrophilicity studies confirmed that grafting of HEMA in the backbone of the hydrophobic chitosan chains induced the improvement in hydrophilicity of chitosan, while mechanical properties of the nanocomposites were also enhanced significantly up to 20%, due to availability of enlarged surface area and higher aspect ratio of CaSO4 nanorods. This was supported by FE-SEM and XRD analysis in terms of proper distribution of nanofiller through the copolymer matrix and corresponding rise in percentage crystallanity respectively. Results obtained from biodegradation studies proved the efficiency of CaSO4 nanofillers to improve biomechanical strength of chitosan nanocomposites, without affecting their normal degradation profile that renders the products to be applicable for biomedical applications.

  18. Recent Modifications of Chitosan for Adsorption Applications: A Critical and Systematic Review

    PubMed Central

    Kyzas, George Z.; Bikiaris, Dimitrios N.

    2015-01-01

    Chitosan is considered to be one of the most promising and applicable materials in adsorption applications. The existence of amino and hydroxyl groups in its molecules contributes to many possible adsorption interactions between chitosan and pollutants (dyes, metals, ions, phenols, pharmaceuticals/drugs, pesticides, herbicides, etc.). These functional groups can help in establishing positions for modification. Based on the learning from previously published works in literature, researchers have achieved a modification of chitosan with a number of different functional groups. This work summarizes the published works of the last three years (2012–2014) regarding the modification reactions of chitosans (grafting, cross-linking, etc.) and their application to adsorption of different environmental pollutants (in liquid-phase). PMID:25584681

  19. Novel anti-infective activities of chitosan immobilized titanium surface with enhanced osteogenic properties.

    PubMed

    Ghimire, Niranjan; Luo, Jie; Tang, Ruogu; Sun, Yuyu; Deng, Ying

    2014-10-01

    We have covalently immobilized chitosan onto a titanium (Ti) surface to manage implant-related infection and poor osseointegration, two of the major complications of orthopedic implants. The Ti surface was first treated with sulfuric acid (SA) and then covalently grafted with chitosan. Surface roughness, contact angle and surface zeta potential of the samples were markedly increased by the sulfuric acid treatment and the subsequent chitosan immobilization. The chitosan-immobilized Ti (SA-CS-Ti) showed two novel antimicrobial roles: it (a) prevented the invasion and internalization of bacteria into the osteoblast-like cells, and (b) significantly increased the susceptibility of adherent bacteria to antibiotics. In addition, the sulfuric acid-treated Ti (SA-Ti) and SA-CS-Ti led to significantly increased (P<0.05) osteoblast-like cell attachment, enhanced cell proliferation, and better osteogenic differentiation and mineralization of osteoblast-like cells.

  20. Temperature measurements for shocked polymethylmethacrylate, epoxy resin, and polytetrafluoroethylene and their equations of state

    NASA Astrophysics Data System (ADS)

    Bordzilovskii, S. A.; Karakhanov, S. M.; Merzhievskii, L. A.; Voronin, M. S.

    2016-10-01

    This paper presents the results of computational and experimental studies of the temperature along the shock adiabat for three polymers. Measurements of the brightness temperatures of shock-compressed epoxy resin and polymethylmethacrylate and the brightness and color temperatures of shock-compressed polytetrafluoroethylene were carried out. The temperatures of the shock-compressed polymethylmethacrylate were determined in the range 1390-1900 K for shock pressures of 22-39 GPa. Similar measurements performed for epoxy resin in the pressure range of 18-40 GPa showed values of 940-1900 K, and the temperatures of polytetrafluoroethylene in the pressure range of 30-50 GPa were equal to 2000-3200 K. The equation of state for the three polymers with a nonspherical strain tensor was constructed to describe shock-wave and high-temperature processes in a wide range of thermodynamic parameters. In the proposed model, two Grüneisen parameters were used: the thermodynamic parameter corresponding to intrachain vibrations and the lattice parameter representing the contribution of interchain vibrations. The brightness temperatures of shocked-compressed polymethylmethacrylate and epoxy resin showed a good agreement with calculations using the proposed model and with the results of earlier calculation methods. Time dependences of the observed intensity of light were used to determine the absorption coefficients of the shocked polymers and estimate the effective thickness of the radiating layer. A typical feature of all the polymers is the width of the radiating layer of 0.8 to 2.5 mm, depending on the material and shock pressure.

  1. Applications of chitosan nanoparticles in drug delivery.

    PubMed

    Tajmir-Riahi, H A; Nafisi, Sh; Sanyakamdhorn, S; Agudelo, D; Chanphai, P

    2014-01-01

    We have reviewed the binding affinities of several antitumor drugs doxorubicin (Dox), N-(trifluoroacetyl) doxorubicin (FDox), tamoxifen (Tam), 4-hydroxytamoxifen (4-Hydroxytam), and endoxifen (Endox) with chitosan nanoparticles of different sizes (chitosan-15, chitosan-100, and chitosan-200 KD) in order to evaluate the efficacy of chitosan nanocarriers in drug delivery systems. Spectroscopic and molecular modeling studies showed the binding sites and the stability of drug-polymer complexes. Drug-chitosan complexation occurred via hydrophobic and hydrophilic contacts as well as H-bonding network. Chitosan-100 KD was the more effective drug carrier than the chitosan-15 and chitosan-200 KD.

  2. Modified Technique for Making Auto-polymerized Polymethylmethacrylate Resin Custom Tray

    PubMed Central

    Reddy, Ramesh; Rajendran, Suresh; Balasubramaniam, Muthu Kumar

    2016-01-01

    Custom made tray for dental impression is designed to provide a uniform space for the impression material and thereby improve the accuracy of the resultant working cast. Auto-polymerized acrylic resins have been the most commonly used material for the fabrication of these trays. The custom tray produces more accurate and reliable results for inter-abutment distance at the occlusal and gingival level than stock trays. This article describes a modified technique for fabrication of auto-polymerized Polymethylmethacrylate (PMMA) resin trays. PMID:28050525

  3. Modified Technique for Making Auto-polymerized Polymethylmethacrylate Resin Custom Tray.

    PubMed

    Chidambaranathan, Ahila Singaravel; Reddy, Ramesh; Rajendran, Suresh; Balasubramaniam, Muthu Kumar

    2016-11-01

    Custom made tray for dental impression is designed to provide a uniform space for the impression material and thereby improve the accuracy of the resultant working cast. Auto-polymerized acrylic resins have been the most commonly used material for the fabrication of these trays. The custom tray produces more accurate and reliable results for inter-abutment distance at the occlusal and gingival level than stock trays. This article describes a modified technique for fabrication of auto-polymerized Polymethylmethacrylate (PMMA) resin trays.

  4. Using rapid prototyping molds to create patient specific polymethylmethacrylate implants in cranioplasty.

    PubMed

    Gerber, N; Stieglitz, L; Peterhans, M; Nolte, L P; Raabe, A; Weber, S

    2010-01-01

    Cranioplasty is a commonly performed procedure. Outcomes can be improved by the use of patient specific implants, however, high costs limit their accessibility. This paper presents a low cost alternative technique to create patient specific polymethylmethacrylate (PMMA) implants using rapid prototyped mold template. We used available patient's CT-scans, one dataset without craniotomy and one with craniotomy, for computer-assisted design of a 3D mold template, which itself can be brought into the operating room and be used for fast and easy building of a PMMA implant. We applied our solution to three patients with positive outcomes and no complications.

  5. Reversible patterning of poly(methylmethacrylate) doped with disperse Red 1 by laser scanning

    SciTech Connect

    Tuma, J.; Lyutakov, O.; Huttel, I.; Slepicka, P.; Svorcik, V.

    2013-09-07

    Thin poly(methylmethacrylate) films doped by or covalently attached to disperse Red 1 acrylate (DR1) were patterned by laser scanning and simultaneous sample movement in confocal microscope. In both cases, periodical structure due to Marangoni effect is created. Modified polymers surfaces were analyzed by FTIR spectroscopy, X-ray photoelectron spectroscopy, and atomic force microscopy. After first stage of patterning, second stage with sample movement in perpendicular direction was applied. Depending on the method of DR1 dotation fishnet structure is obtained or pattern structure disappears. In the latter case, reversibility of pattern formation and erasure by laser scanning was studied.

  6. Influence of irradiation on the Heterogeneity of polymethylmethacrylate-polyvinylidene fluoride mixtures

    SciTech Connect

    Lipatov, Y.S.; Bliznyuk, V.N.; Boyarskii, G.Y.; Gomza, Y.P.; Shilov, V.V.

    1985-11-01

    Small- and wide-angle x-ray scattering was used to investigate the phase structure of mixtures of polymethylmethacrylate (PMMA) with polyvinylidene fluoride (PVDF) as function of the thermal treatment and the ..gamma..-radiation dose. Irradiation of 1/ 1 mixtures obtained by quenching from a homogeneous melt with doses of up to 1 Mrd leads to radiation breakdown of the components; on the other hand, irradiation with larger doses leads to radiation crosslinking of PVDF. ..gamma..-Irradiation accelerates phase separation in the system, as a result of which microregions of pure PVDF of colloidal size are formed.

  7. Occlusion of an Intraosseous Arteriovenous Malformation With Percutaneous Injection of Polymethylmethacrylate

    SciTech Connect

    Ierardi, Anna Maria; Mangini, Monica; Vaghi, Massimo; Cazzulani, Alberto; Mattassi, Raul; Carrafiello, Gianpaolo

    2011-02-15

    Primary intraosseous arteriovenous malformations are rare. Many minimally invasive procedures can be considered preoperative steps and/or definitive treatment. The case reported regards a young woman with a voluminous arteriovenous extratroncular infiltrating malformation of the humerus. She underwent several treatments, but none of them was completely occlusive. The last treatment consisted of direct percutaneous puncture of the intraosseous alteration and injection of polymethylmethacrylate (PMMA), which is normally used in percutaneous vertebroplasty. We obtained complete occlusion of the humerus lytic lesion. To the best of our knowledge, this represents the first case of intraosseous AVM treated by percutaneous injection of PMMA.

  8. Synthesis and study of thermal, mechanical and biodegradation properties of chitosan-g-PMMA with chicken egg shell (nano-CaO) as a novel bio-filler.

    PubMed

    Pradhan, Arun K; Sahoo, Prafulla K

    2017-11-01

    The important objective of this study is to evaluate the effect of chicken eggshell (nano-Cao) as a functionalized bio-filler on the mechanical strength and thermal stability of acrylic based bionanocomposite of chitosan grafted with poly(methyl methacrylate)(PMMA). The chitosan grafted PMMA adsorbed with functionalized biofiller was prepared via emulsion polymerisation technique and physicochemically characterized as bone graft substitute. The so prepared grafted bioactive bone cement (BBC) bionanocomposite (BNC), chitosan-g-PMMA/nano-CaO was characterized by FTIR, XRD, FESEM and TGA. The water uptake, retention ability, their biodegradability and the nanosize particle arrangement in the polymeric BBC-BNCs were undertaken. These preliminary investigations of the BNCs will open the door for their use in bioadhesive bone cement implants in future. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. Peptide-decorated chitosan derivatives enhance fibroblast adhesion and proliferation in wound healing.

    PubMed

    Patrulea, V; Hirt-Burri, N; Jeannerat, A; Applegate, L A; Ostafe, V; Jordan, O; Borchard, G

    2016-05-20

    RGD peptide sequences are known to regulate cellular activities by interacting with α5β1, αvβ5 and αvβ3 integrin, which contributes to the wound healing process. In this study, RGDC peptide was immobilized onto chitosan derivative 1,6-diaminohexane-O-carboxymethyl-N,N,N-trimethyl chitosan (DAH-CMTMC) to display RGDC-promoting adhesion for enhanced wound healing. The efficiency of N-methylation, O-carboxymethylation and spacer grafting was quantitatively and qualitatively analyzed by (1)H NMR and FTIR, yielding 0.38 degree of substitution for N-methylation and >0.85 for O-carboxymethylation. The glass transition temperatures for chitosan derivatives were also studied. Peptide immobilization was achieved through sulfhydryl groups using sulfosuccinimidyl (4-iodoacetyl)amino-benzoate (sulfo-SIAB method). RGDC immobilized peptide onto DAH-CMTMC was found to be about 15.3 μg/mg of chitosan derivative by amino acid analysis (AAA). The significant increase of human dermal fibroblast (HDF) viability in vitro over 7 days suggests that RGDC-functionalized chitosan may lead to enhanced wound healing (viability >140%). Moreover, bio-adhesion and proliferation assays confirmed that coatings of RGDC-functionalized chitosan derivatives exhibit in vitro wound healing properties by enhancing fibroblast proliferation and adhesion. These results showed that RGDC peptide-functionalized chitosan provides an optimal environment for fibroblast adhesion and proliferation.

  10. Chitosan-g-hematin: enzyme-mimicking polymeric catalyst for adhesive hydrogels.

    PubMed

    Ryu, Ji Hyun; Lee, Yuhan; Do, Min Jae; Jo, Sung Duk; Kim, Jee Seon; Kim, Byung-Soo; Im, Gun-Il; Park, Tae Gwan; Lee, Haeshin

    2014-01-01

    Phenol derivative-containing adhesive hydrogels has been widely recognized as having potential for biomedical applications, but their conventional production methods, utilizing a moderate/strong base, alkaline buffers, the addition of oxidizing agents or the use of enzymes, require alternative approaches to improve their biocompatibility. In this study, we report a polymeric, enzyme-mimetic biocatalyst, hematin-grafted chitosan (chitosan-g-hem), which results in effective gelation without the use of alkaline buffers or enzymes. Furthermore, gelation occurs under mild physiological conditions. Chitosan-g-hem biocatalyst (0.01%, w/v) has excellent catalytic properties, forming chitosan-catechol hydrogels rapidly (within 5 min). In vivo adhesive force measurement demonstrated that the hydrogel formed by the chitosan-g-hem activity showed an increase in adhesion force (33.6 ± 5.9 kPa) compared with the same hydrogel formed by pH-induced catechol oxidation (20.6 ± 5.5 kPa) in mouse subcutaneous tissue. Using the chitosan-g-hem biocatalyst, other catechol-functionalized polymers (hyaluronic acid-catechol and poly(vinyl alcohol)-catechol) also formed hydrogels, indicating that chitosan-g-hem can be used as a general polymeric catalyst for preparing catechol-containing hydrogels. Copyright © 2013 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  11. Uncoupling chitosanase production from chitosan.

    PubMed

    Brzezinski, Ryszard

    2011-01-01

    There is a growing interest in chitosanases as enzymatic tools to hydrolyze chitosan into bioactive forms: low molecular weight chitosan (LMWC) or chitosan oligosaccharides (CHOS). However chitosanases are still expensive and methods of large-scale production of these enzymes are not yet established. The article reviews the approaches used for chitosanase production in various bacterial hosts, pointing out the difficulties resulting from the necessity to include chitosan into the medium composition. A mutated Streptomyces host allows for the efficient production of several chitosanases originating from actinobacteria in the absence of chitosan as inducer.

  12. DNA/chitosan electrostatic complex.

    PubMed

    Bravo-Anaya, Lourdes Mónica; Soltero, J F Armando; Rinaudo, Marguerite

    2016-07-01

    Up to now, chitosan and DNA have been investigated for gene delivery due to chitosan advantages. It is recognized that chitosan is a biocompatible and biodegradable non-viral vector that does not produce immunological reactions, contrary to viral vectors. Chitosan has also been used and studied for its ability to protect DNA against nuclease degradation and to transfect DNA into several kinds of cells. In this work, high molecular weight DNA is compacted with chitosan. DNA-chitosan complex stoichiometry, net charge, dimensions, conformation and thermal stability are determined and discussed. The influence of external salt and chitosan molecular weight on the stoichiometry is also discussed. The isoelectric point of the complexes was found to be directly related to the protonation degree of chitosan. It is clearly demonstrated that the net charge of DNA-chitosan complex can be expressed in terms of the ratio [NH3(+)]/[P(-)], showing that the electrostatic interactions between DNA and chitosan are the main phenomena taking place in the solution. Compaction of DNA long chain complexed with low molar mass chitosan gives nanoparticles with an average radius around 150nm. Stable nanoparticles are obtained for a partial neutralization of phosphate ionic sites (i.e.: [NH3(+)]/[P(-)] fraction between 0.35 and 0.80).

  13. Physical characterization and osteogenic activity of the quaternized chitosan-loaded PMMA bone cement.

    PubMed

    Tan, Honglue; Guo, Shengrong; Yang, Shengbing; Xu, Xiaofen; Tang, Tingting

    2012-07-01

    Gentamicin-loaded polymethylmethacrylate (PMMA), widely used for primary cemented arthroplasty and revision surgery for preventing or treating infections, may lead to the evolution of antibiotic-resistant bacteria and dysfunction of osteogenic cells, which further influence the osteointegration of bone cement. In a previous study, we reported that a new quaternized chitosan derivative (hydroxypropyltrimethyl ammonium chloride chitosan, HACC) that was loaded into PMMA significantly inhibited the formation of biofilms caused by methicillin-resistant Staphylococcus strains. In the present study, we further investigated the surface morphology, hydrophilicity, apatite formation ability and osteogenic activity of HACC-loaded PMMA. Chitosan-loaded PMMA, gentamicin-loaded PMMA and PMMA without antibiotic were also investigated and compared. The results showed that, compared to other PMMA-based cements, HACC-loaded PMMA had improved properties such as a lower polymerization temperature, prolonged setting time, porous structures after immersion in phosphate-buffered saline, higher hydrophilicity, more apatite formation on the surface after immersion in simulated body fluid, and better attachment and spreading of the human-marrow-derived mesenchymal stem cells. We also found better stem cell proliferation, osteogenic differentiation, and osteogenesis-associated genes expression on the surface of the HACC-loaded PMMA compared to the gentamicin-loaded PMMA. Therefore, this new anti-infective bone cement had improved physical properties and osteogenic activity, which may lead to better osteointegration of the bone cement in cemented arthroplasty.

  14. Chitosan in plant protection.

    PubMed

    El Hadrami, Abdelbasset; Adam, Lorne R; El Hadrami, Ismail; Daayf, Fouad

    2010-03-30

    Chitin and chitosan are naturally-occurring compounds that have potential in agriculture with regard to controlling plant diseases. These molecules were shown to display toxicity and inhibit fungal growth and development. They were reported to be active against viruses, bacteria and other pests. Fragments from chitin and chitosan are known to have eliciting activities leading to a variety of defense responses in host plants in response to microbial infections, including the accumulation of phytoalexins, pathogen-related (PR) proteins and proteinase inhibitors, lignin synthesis, and callose formation. Based on these and other proprieties that help strengthen host plant defenses, interest has been growing in using them in agricultural systems to reduce the negative impact of diseases on yield and quality of crops. This review recapitulates the properties and uses of chitin, chitosan, and their derivatives, and will focus on their applications and mechanisms of action during plant-pathogen interactions.

  15. Chitosan in Plant Protection

    PubMed Central

    El Hadrami, Abdelbasset; Adam, Lorne R.; El Hadrami, Ismail; Daayf, Fouad

    2010-01-01

    Chitin and chitosan are naturally-occurring compounds that have potential in agriculture with regard to controlling plant diseases. These molecules were shown to display toxicity and inhibit fungal growth and development. They were reported to be active against viruses, bacteria and other pests. Fragments from chitin and chitosan are known to have eliciting activities leading to a variety of defense responses in host plants in response to microbial infections, including the accumulation of phytoalexins, pathogen-related (PR) proteins and proteinase inhibitors, lignin synthesis, and callose formation. Based on these and other proprieties that help strengthen host plant defenses, interest has been growing in using them in agricultural systems to reduce the negative impact of diseases on yield and quality of crops. This review recapitulates the properties and uses of chitin, chitosan, and their derivatives, and will focus on their applications and mechanisms of action during plant-pathogen interactions. PMID:20479963

  16. Antibiotic-Releasing Porous Polymethylmethacrylate/Gelatin/Antibiotic Constructs for Craniofacial Tissue Engineering

    PubMed Central

    Shi, Meng; Kretlow, James D.; Spicer, Patrick P.; Tabata, Yasuhiko; Demian, Nagi; Wong, Mark E.; Kasper, F. Kurtis; Mikos, Antonios G.

    2011-01-01

    An antibiotic-releasing porous polymethylmethacrylate (PMMA) construct was developed to maintain the bony space and prime the wound site in the initial step of a two-stage regenerative medicine approach toward reconstructing significant bony or composite craniofacial tissue defects. Porous polymethylmethacrylate (PMMA) constructs incorporating gelatin microparticles (GMPs) were fabricated by the sequential assembly of GMPs, the antibiotic colistin, and a clinically used bone cement formulation of PMMA powder and methylmethacrylate liquid. PMMA/gelatin/antibiotic constructs with varying gelatin incorporation and drug content were investigated to elucidate the relationship between material composition and construct properties (porosity and drug release kinetics). The porosity of PMMA/gelatin/antibiotic constructs ranged between 7.6±1.8–38.4±1.4% depending on the amount of gelatin incorporated and the drug solution added for gelatin swelling. The constructs released colistin over 10 or 14 days with an average release rate per day above 10 µg/ml. The porosity and in vitro colistin release kinetics of PMMA/gelatin/antibiotic constructs were tuned by varying the material composition and fabrication parameters. This study demonstrates the potential of gelatin-incorporating PMMA constructs as a functional space maintainer for both promoting tissue healing/coverage and addressing local infections, enabling better long-term success of the definitive regenerated tissue construct. PMID:21295086

  17. Computer-aided design and manufacture and rapid prototyped polymethylmethacrylate reconstruction.

    PubMed

    Turgut, Gürsel; Özkaya, Özay; Kayali, Mahmut Ulvi

    2012-05-01

    This article discusses the application of computer-aided design and rapid prototyping techniques in polymethylmethacrylate reconstruction of craniofacial bone defects. This method avoids the probability of tissue damage due to exothermic reaction during the polymerization process and provides precise implants that exactly fit the defects. A total of 11 patients who have various-sized craniofacial defects underwent polymethylmethacrylate reconstruction. We performed three-dimensional reconstruction and operative design using computer software. According to the design, we determined the shape and size of the implants and made individualized implants for craniofacial bone defects with the rapid prototyping technique. With the application of computer-aided design and a rapid prototyping technique, we could accurately determine the shape, size, and embedding location. Prefabricating the individual implant models is useful in improving the accuracy of treatment. No cases of infection, seroma, extrusion, or contour irregularity occurred as a complication, and all patients were satisfied with the results. During the follow-up period, ranging from 1 to 6 years, all patients remained satisfied, and no complications were sustained. In cases of various-sized cranial defects and complex maxillofacial defects that have enough soft tissue coverage and that do not have contact with a third space, prefabricated methyl methacrylate implants can be used safely. Patients will feel more comfortable if the postoperative shape resembles the original appearance, so the proposed algorithm effectively creates a customized implant.

  18. Synthesis, self-assembly, and cytotoxicity of well-defined trimethylated chitosan-O-poly(ε-caprolactone): effect of chitosan molecular weight.

    PubMed

    Zhang, Haiwen; Cai, Guoqiang; Tang, Guping; Wang, Liqun; Jiang, Hongliang

    2011-08-01

    Structurally well-defined trimethylated chitosan-O-poly(ε-caprolactone) (TMC-O-PCL) was synthesized under mild homogeneous conditions, using sodium dodecyl sulfate-dimethylated chitosan complex (SDC) as an organosoluble intermediate. The effect of chitosan molecular weight (MW) on the preparation, organosolubility, self-assembly, and cytotoxicity of the copolymers was investigated. The copolymers with low-MW chitosan backbone had improved solubility in common organic solvents. Spherical micelles with average diameter of 25-55 nm and uniform morphology were formed through self-assembly of TMC-O-PCL in pH 7.4 PBS. When trimethylation degree of the copolymers was above 44%, the micelles could remain stable in neutral aqueous media. The critical aggregation concentration of TMC-O-PCL slightly increased with a decrease in the MW of chitosan backbone. The cytotoxicity of the cationic micelles could be suppressed by increasing PCL grafting levels, reducing trimethylation degree, and MW of the chitosan backbone. Copyright © 2011 Wiley Periodicals, Inc.

  19. One-step biofunctionalization of quantum dots with chitosan and N-palmitoyl chitosan for potential biomedical applications.

    PubMed

    Santos, Joyce C C; Mansur, Alexandra A P; Mansur, Herman S

    2013-06-04

    Carbohydrates and derivatives (such as glycolipids, glycoproteins) are of critical importance for cell structure, metabolism and functions. The effects of carbohydrate and lipid metabolic imbalances most often cause health disorders and diseases. In this study, new carbohydrate-based nanobioconjugates were designed and synthesized at room temperature using a single-step aqueous route combining chitosan and acyl-modified chitosan with fluorescent inorganic nanoparticles. N-palmitoyl chitosan (C-Pal) was prepared aiming at altering the lipophilic behavior of chitosan (CHI), but also retaining its reasonable water solubility for potential biomedical applications. CHI and C-Pal were used for producing biofunctionalized CdS quantum dots (QDs) as colloidal water dispersions. Fourier transform infrared spectroscopy (FTIR), thermal analysis (TG/DSC), surface contact angle (SCA), and degree of swelling (DS) in phosphate buffer were used to characterize the carbohydrates. Additionally, UV-Visible spectroscopy (UV-Vis), photoluminescence spectroscopy (PL), dynamic light scattering (DLS), scanning and transmission electron microscopy (SEM/TEM) were used to evaluate the precursors and nanobioconjugates produced. The FTIR spectra associated with the thermal analysis results have undoubtedly indicated the presence of N-palmitoyl groups "grafted" to the chitosan chain (C-Pal) which significantly altered its behavior towards water swelling and surface contact angle as compared to the unmodified chitosan. Furthermore, the results have evidenced that both CHI and C-Pal performed as capping ligands on nucleating and stabilizing colloidal CdS QDs with estimated average size below 3.5 nm and fluorescent activity in the visible range of the spectra. Therefore, an innovative "one-step" process was developed via room temperature aqueous colloidal chemistry for producing biofunctionalized quantum dots using water soluble carbohydrates tailored with amphiphilic behavior offering potential

  20. A novel glutathione modified chitosan conjugate for efficient gene delivery.

    PubMed

    Li, Congxin; Guo, Tianying; Zhou, Dezhong; Hu, Yuling; Zhou, Hao; Wang, Shufang; Chen, Jiatong; Zhang, Zhengpu

    2011-09-05

    A novel non-viral gene vector based on poly[poly(ethylene glycol) methacrylate] (PMPEG) and l-glutathione (GSH) grafted chitosan (CS) has been fabricated. First, well-defined brush-like PMPEG living polymers with dithioester residues were prepared by the reversible addition-fragmentation chain transfer (RAFT) polymerization and grafted onto the allylchitosan via radical coupling method. Then, the tripeptide GSH was introduced onto the end of PMPEG chain to give a CS-PMPEG-GSH conjugate. In comparison with pristine chitosan, CS-PMPEG-GSH conjugate could not only condense plasmid DNA (pDNA) and prevent the condensed CS-PMPEG-GSH/pDNA nanoparticle self-aggregation, but also increase the binding ability to cell membrane efficiently and improve decondensed ability of pDNA from the nanoparticles in cytoplasm which thus has resulted in the higher transfection efficiency in mouse embryonic fibroblast cells (NIH3T3). In addition, cytotoxicity assays showed that the conjugate is less cytotoxic than CS, and still retain the cationic polyelectrolyte characteristic as chitosan. These results indicate that the non-viral vector is a promising candidate for gene therapy in clinical application.

  1. Proximal Tibial Bone Graft

    MedlinePlus

    ... All Site Content AOFAS / FootCareMD / Treatments Proximal Tibial Bone Graft Page Content What is a bone graft? Bone grafts may be needed for various ... the proximal tibia. What is a proximal tibial bone graft? Proximal tibial bone graft (PTBG) is a ...

  2. Application of chitosan and its derivatives as adsorbents for dye removal from water and wastewater: a review.

    PubMed

    Vakili, Mohammadtaghi; Rafatullah, Mohd; Salamatinia, Babak; Abdullah, Ahmad Zuhairi; Ibrahim, Mahamad Hakimi; Tan, Kok Bing; Gholami, Zahra; Amouzgar, Parisa

    2014-11-26

    Chitosan based adsorbents have received a lot of attention for adsorption of dyes. Various modifications of this polysaccharide have been investigated to improve the adsorption properties as well as mechanical and physical characteristics of chitosan. This review paper discusses major research topics related to chitosan and its derivatives for application in the removal of dyes from water. Modification of chitosan changes the original properties of this material so that it can be more suitable for adsorption of different types of dye. Many chitosan derivatives have been obtained through chemical and physical modifications of raw chitosan that include cross-linking, grafting and impregnation of the chitosan backbone. Better understanding of these varieties and their affinity toward different types of dye can help future research to be properly oriented to address knowledge gaps in this area. This review provides better opportunity for researchers to better explore the potential of chitosan-derived adsorbents for removal of a great variety of dyes. Copyright © 2014 Elsevier Ltd. All rights reserved.

  3. Mid-term outcome after curettage with polymethylmethacrylate for giant cell tumor around the knee: higher risk of radiographic osteoarthritis?

    PubMed

    van der Heijden, Lizz; van de Sande, Michiel A J; Heineken, Adriaan C; Fiocco, Marta; Nelissen, Rob G H H; Dijkstra, P D Sander

    2013-11-06

    It has been suggested that, when a patient has a giant cell tumor, subchondral bone involvement close to articular cartilage and a hyperthermic reaction from polymethylmethacrylate (PMMA) are risk factors for the development of osteoarthritis. We determined the prevalence, risk factors, and clinical relevance of osteoarthritis on radiographs after curettage and application of PMMA for the treatment of giant cell tumors around the knee. This retrospective single-center study included fifty-three patients with giant cell tumor around the knee treated with curettage and PMMA between 1987 and 2007. The median age at the time of follow-up was forty-two years (range, twenty-three to seventy years). There were twenty-nine women. Radiographic evidence of osteoarthritis was defined, preoperatively and postoperatively, as Kellgren and Lawrence grade 3 or 4 (KL3-4). We studied the influence of age, sex, tumor-cartilage distance, subchondral bone involvement (≤3 mm of residual subchondral bone), subchondral bone-grafting, intra-articular fracture, multiple curettage procedures, and complications on progression to KL3-4. Functional outcomes and quality of life were assessed with the Short Form-36 (SF-36), Musculoskeletal Tumor Society (MSTS) score, and Knee injury and Osteoarthritis Outcome Score (KOOS). After a median duration of follow-up of eighty-six months (range, sixty to 285 months), six patients (11%) had progression to KL3, two (4%) had progression to KL4, and one had preexistent KL4. No patient underwent total knee replacement. The hazard ratio for KL3-4 was 9.0 (95% confidence interval [CI] = 2.0 to 41; p = 0.004) when >70% of the subchondral bone was affected and 4.2 (95% CI = 0.84 to 21; p = 0.081) when the tumor-cartilage distance was ≤3 mm. Age, sex, subchondral bone-grafting, intra-articular fracture, multiple curettage procedures, and complications did not affect progression to KL3-4. Patients with KL3-4 reported lower scores on the KOOS symptom subscale

  4. Hydrophobically modified chitosan: a bio-based material for antimicrobial active film.

    PubMed

    Inta, Orathai; Yoksan, Rangrong; Limtrakul, Jumras

    2014-09-01

    The objective of the present research was to improve the hydrophobicity of chitosan, while retaining its antibacterial activity, through the grafting of dodecenyl succinyl chains onto phthaloyl chitosan, mainly at the C-6 position. Dodecenyl succinylated phthaloyl chitosan (DS-g-PHCTS) was synthesized via phthaloylation-dodecenyl succinylation-hydrazinolysis. The obtained derivatives were characterized by FTIR, (1)H NMR and XRD. Hydrazinolysis time was found to be a key factor in controlling the substitution of dodecenyl succinyl chains and phthalimido groups of the final product. DS-g-PHCTS - with a grafting degree of dodecenyl succinyl chains and a substitution degree of phthalimido groups of 0.73 and 0.39, respectively - exhibited an anhydrous crystal structure and the same solubility behavior as native chitosan. The introduction of hydrophobic alkyl chains provided DS-g-PHCTS with enhanced antibacterial activity against Gram-positive bacteria. In addition, DS-g-PHCTS film showed more effective bacterial growth inhibition and better water vapor barrier property under neutral pH condition than chitosan film. The results suggested that DS-g-PHCTS film could be potentially used as antibacterial active film. Copyright © 2014 Elsevier B.V. All rights reserved.

  5. Coronary Artery Bypass Grafting

    MedlinePlus

    ... from the NHLBI on Twitter. What Is Coronary Artery Bypass Grafting? Coronary artery bypass grafting (CABG) is ... bypass multiple coronary arteries during one surgery. Coronary Artery Bypass Grafting Figure A shows the location of ...

  6. Preparation and characterization of poly(2-acrylamido-2-methylpropane-sulfonic acid)/Chitosan hydrogel using gamma irradiation and its application in wastewater treatment

    NASA Astrophysics Data System (ADS)

    Gad, Y. H.

    2008-09-01

    Radiation grafting of chitosan with 2-acrylamido-2-methyl propane sulfonic acid (AMPS) has been successfully performed. The effect of absorbed dose (kGy) and the chitosan:AMPS ratio on graft hydrogelization was studied. The structure of the prepared hydrogel was confirmed using infrared spectroscopy (IR). Thermal properties were simultaneously studied by thermogravimetric analysis (TGA). The effect of the polymerization variables on the swelling % of the prepared hydrogel was investigated. The highest equilibrium degree of swelling (38.6 g/g) and gel % (94.7%) of the prepared chitosan-AMPS hydrogel was at 40% AMPS and absorbed dose of 10 kGy. The removal of methylene blue, acid red dye, Cd (II) and Cr (III) from composed wastewater was also investigated. The effect of pH, the chitosan:AMPS ratio and the concentration of the pollutant on the adsorption process were studied.

  7. Development of chitosan-crosslinked nanofibrous PHBV guide for repair of nerve defects.

    PubMed

    Biazar, Esmaeil; Heidari Keshel, Saeed

    2014-12-01

    The aim of this study was to produce a chitosan-crosslinked nanofibrous biodegradable poly (3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) nerve conduit. The artificial scaffold was designed by electrospinning method, and cross-linked with chitosan by chemical method. The scaffolds were evaluated by microscopic, physical, and mechanical analyses, and cell culture assays with Schwann cells. Results of analyses showed a good resilience and compliance with movement as a neural graft. Cellular experiments showed a better cell adhesion and growth inside the crosslinked nanofibrous scaffolds compared with un-crosslinked ones. This neural conduit appears to have the right organization for testing in vivo nerve tissue engineering studies.

  8. Biodegradability and biocompatibility study of poly(chitosan-g-lactic acid) scaffolds.

    PubMed

    Zhang, Zhe; Cui, Huifei

    2012-03-14

    A biodegradable, biocompatible poly(chitosan-g-lactic acid) (PCLA) scaffold was prepared and evaluated in vitro and in vivo. The PCLA scaffold was obtained by grafting lactic acid (LA) onto the amino groups on chitosan (CS) without a catalyst. The PCLA scaffolds were characterized by Fourier Transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM). The biodegradabilty was determined by mass loss in vitro, and degradation in vivo as a function of feed ratio of LA/CS. Bone marrow mesenchymal stem cell (BMSC) culture experiments and histological examination were performed to evaluate the PCLA scaffolds' biocompatibility. The results indicated that PCLA was promising for tissue engineering application.

  9. Comparative studies on the removal of heavy metals ions onto cross linked chitosan-g-acrylonitrile copolymer.

    PubMed

    Shankar, P; Gomathi, Thandapani; Vijayalakshmi, K; Sudha, P N

    2014-06-01

    The graft copolymerization of acrylonitrile onto cross linked chitosan was carried out using ceric ammonium nitrate as an initiator. The prepared cross linked chitosan-g-acrylonitrile copolymer was characterized using FT-IR and XRD studies. The adsorption behavior of chromium(VI), copper(II) and nickel(II) ions from aqueous solution onto cross linked chitosan graft acrylonitrile copolymer was investigated through batch method. The efficiency of the adsorbent was identified from the varying the contact time, adsorbent dose and pH. The results evident that the adsorption of metal ions increases with the increase of shaking time and metal ion concentration. An optimum pH was found to be 5.0 for both Cr(VI) and Cu(II), whereas the optimum pH is 5.5 for the adsorption of Ni(II) onto cross linked chitosan-g-acrylonitrile copolymer. The Langmuir and Freundlich adsorption models were applied to describe the isotherms and isotherm constants. Adsorption isothermal data could be well interpreted by the Freundlich model. The kinetic experimental data properly correlated with the second-order kinetic model. From the above results it was concluded that the cross linked chitosan graft acrylonitrile copolymer was found to be the efficient adsorbent for removing the heavy metals under optimum conditions.

  10. Surface energy changes produced by ultraviolet-ozone irradiation of poly(methylmethacrylate), polycarbone and polytetrafluoroethylene

    NASA Technical Reports Server (NTRS)

    Ponter, A. B.; Jones, W. R., Jr.; Jansen, R. H.

    1994-01-01

    Contact angles of water and methylene iodide were measured as a function of UV/O3 treatment time for three polymers: poly(methylmethacrylate) (PMMA), polycarbonate, and polytetrafluoroethylene (PTFE). Surface roughnesses were also measured. Surface free energies were then calculated using relationships developed by Kaelble and Neumann. The surface energy of polycarbonate was found to increase (60 percent) during UV/O3 treatment. However, calculations on PMMA were hampered by the formation of a water soluble surface product. On PTFE surfaces, the UV/O3 treatment etched the surface causing large increases in surface roughness, rendering contact angle measurements impossible. It is concluded that care must be taken in interpreting contact angle measurements and surface energy calculations on UV/O3 treated polymer surfaces.

  11. Tissue biocompatibility of kevlar aramid fibers and polymethylmethacrylate, composites in rabbits.

    PubMed

    Henderson, J D; Mullarky, R H; Ryan, D E

    1987-01-01

    Two groups of female NZW rabbits were implanted in the paravertebral muscles with aramid (du Pont Kevlar aramid 49) fibers and aramid-polymethylmethacrylate (PMMA) composites for 14 and 28 days. Rabbits were killed at these times periods, necropsies performed, sites scored for gross tissue response, and tissue specimens containing the implants removed for histopathological evaluation. A mild fibrous tissue reaction was observed around all implants containing aramid fiber similar to that observed around the silicone control implant. Some foreign body giant cells were also present adjacent to the fibers. An intense necrotic inflammatory reaction was present around the positive control material (PVC Y-78). The tissue response to implantation of aramid fiber and fiber-PMMA composites indicates that aramid is a biocompatible material.

  12. Reconstruction of bony facial contour deficiencies with polymethylmethacrylate implants: case report

    PubMed Central

    ABDO FILHO, Ruy C. C.; OLIVEIRA, Thais M.; LOURENÇO, Natalino; GURGEL, Carla; ABDO, Ruy C.C.

    2011-01-01

    Facial trauma can be considered one of the most serious aggressions found in the medical centers due to the emotional consequences and the possibility of deformity. In craniofacial surgery, the use of autologous bone is still the first choice for reconstructing bony defects or irregularities. When there is a shortage of donor bone or a patient refuses an intracranial operation, alloplastic materials such as polymethylmethacrylate (PMMA) can be used. The PMMA prosthesis can be pre-fabricated, bringing advantages such as reduction of surgical time, easy technical handling and good esthetic results. This paper describes the procedures for rehabilitating a patient with PMMA implants in the region of the face, recovering the facial contours and esthetics of the patient. PMID:21952926

  13. The WS2 quantum dot: preparation, characterization and its optical limiting effect in polymethylmethacrylate

    NASA Astrophysics Data System (ADS)

    Long, Hui; Tao, Lili; Chiu, Chun Pang; Tang, Chun Yin; Fung, Kin Hung; Chai, Yang; Tsang, Yuen Hong

    2016-10-01

    Due to the matching surface energy, WS2 quantum dots (QDs) can be obtained through direct liquid exfoliation in N-methyl-2-pyrrolidone rather than an ethanol and water mixture. Ultra-small WS2 QDs with a diameter of 2.4 nm are fabricated by an ultrasound method followed by high speed centrifugation up to 10 000 rpm. An excellent nonlinear optical (NLO) property of the WS2 QD/ polymethylmethacrylate (PMMA) composite for the nanosecond pulsed laser at both 532 and 1064 nm has been measured. Results illustrate the lower onset thresholds (F ON ), lower optical limiting thresholds (F OL ), and higher two-photon absorption coefficient (β) with respect to a higher concentration of embedded WS2 QDs into the PMMA solid state matrix for both 532 and 1064 nm.

  14. Manufacturing of embedded multimode waveguides by reactive lamination of cyclic olefin polymer and polymethylmethacrylate

    NASA Astrophysics Data System (ADS)

    Kelb, Christian; Rother, Raimund; Schuler, Anne-Katrin; Hinkelmann, Moritz; Rahlves, Maik; Prucker, Oswald; Müller, Claas; Rühe, Jürgen; Reithmeier, Eduard; Roth, Bernhard

    2016-03-01

    We demonstrate the manufacturing of embedded multimode optical waveguides through linking of polymethylmethacrylate (PMMA) foils and cyclic olefin polymer (COP) filaments based on a lamination process. Since the two polymeric materials cannot be fused together through interdiffusion of polymer chains, we utilize a reactive lamination agent based on PMMA copolymers containing photoreactive 2-acryloyloxyanthraquinone units, which allows the creation of monolithic PMMA-COP substrates through C-H insertion reactions across the interface between the two materials. We elucidate the lamination process and evaluate the chemical link between filament and foils by carrying out extraction tests with a custom-built tensile testing machine. We also show attenuation measurements of the manufactured waveguides for different manufacturing parameters. The lamination process is in particular suited for large-scale and low-cost fabrication of board-level devices with optical waveguides or other micro-optical structures, e.g., optofluidic devices.

  15. In vitro and in vivo evaluation of antibiotic diffusion from antibiotic-impregnated polymethylmethacrylate beads.

    PubMed

    Adams, K; Couch, L; Cierny, G; Calhoun, J; Mader, J T

    1992-05-01

    The elution of antibiotics from antibiotic-impregnated polymethylmethacrylate (PMMA) beads was measured in mongrel dogs. The antibiotics, used in mixture with Simplex cement, included cefazolin (Ancef; 4.5 g/40 g cement powder), ciprofloxacin (Cipro; 6 g/40 g powder), clindamycin (Cleocin; 6 g/40 g powder), ticarcillin (Ticar; 12 g/40 g powder), tobramycin (Nebcin; 9.8 g/40 g powder), and vancomycin (Vancocin; 4 g/40 g powder). After a pneumatic drill was used to dredge a trough in the tibia, five beads were implanted. During the next 28 days, seroma samples and serum samples were taken for antibiotic measurements. On Day 28, the dogs were killed, beads removed, and the seroma, serum, bone, and granulation tissue sampled. The results of the study showed that clindamycin, vancomycin, and tobramycin exhibited good elution characteristics and had consistently high levels in bone and granulation tissue.

  16. A study of laser-based removal of polymethylmethacrylate bone cement.

    PubMed

    O'Neill, W; Kapadia, P; Thomas, T

    1996-06-01

    Complications are often produced with the removal of bone cement from the femoral cavity in the treatment of a failed hip prosthesis. Apart from being slow and difficult the conventional process runs the risk of producing damage to the femur. Ultrasonic techniques have been suggested to achieve these ends but removal of the cement by this approach is not entirely easy. The alternative laser-based approach would seem to have significant advantages over conventional techniques. The laser is capable of delivering energy to a specific region or surface under close control. The choice of laser is determined by its ability to ablate the cement and the ease with which it can be delivered to the base of the femur cavity. This paper examines several laser wavelengths: CO2 (10.6 microns), excimer (248 nm), Hol:YAG (2.12 microns), and presents polymethylmethacrylate (PMMA) vaporization thresholds for each laser.

  17. Communication: Effect of density on the physical aging of pressure-densified polymethylmethacrylate

    NASA Astrophysics Data System (ADS)

    Casalini, R.; Roland, C. M.

    2017-09-01

    The rate of physical aging of glassy polymethylmethacrylate (PMMA), followed from the change in the secondary relaxation with aging, is found to be independent of the density, the latter controlled by the pressure during glass formation. Thus, the aging behavior of the secondary relaxation is the same whether the glass is more compacted or less dense than the corresponding equilibrium liquid. This equivalence in aging of glasses formed under different pressures indicates that local packing is the dominant variable governing the glassy dynamics. The fact that pressure densification yields different glass structures is at odds with a model for non-associated materials having dynamic properties exhibited by PMMA, such as density scaling of the relaxation time and isochronal superposition of the relaxation dispersion.

  18. Towards disposable lab-on-a-chip: poly(methylmethacrylate) microchip electrophoresis device with electrochemical detection.

    PubMed

    Wang, Joseph; Pumera, Martin; Chatrathi, Madhu Prakash; Escarpa, Alberto; Konrad, Renate; Griebel, Anja; Dörner, Wolfgang; Löwe, Holger

    2002-02-01

    A fully disposable microanalytical device based on combination of poly(methylmethacrylate) (PMMA) capillary electrophoresis microchips and thick-film electrochemical detector strips is described. Variables influencing the separation efficiency and amperometric response, including separation voltage or detection potential are assessed and optimized. The versatility, simplicity and low-cost advantages of the new design are coupled to an attractive analytical performance, with good precision (relative standard deviation RSD = 1.68% for n = 10). Applicability for assays of mixtures of hydrazine, phenolic compounds, and catecholamines is demonstrated. Such coupling of low-cost PMMA-based microchips with thick-film electrochemical detectors holds great promise for mass production of single-use micrototal analytical systems.

  19. Communication: Effect of density on the physical aging of pressure-densified polymethylmethacrylate.

    PubMed

    Casalini, R; Roland, C M

    2017-09-07

    The rate of physical aging of glassy polymethylmethacrylate (PMMA), followed from the change in the secondary relaxation with aging, is found to be independent of the density, the latter controlled by the pressure during glass formation. Thus, the aging behavior of the secondary relaxation is the same whether the glass is more compacted or less dense than the corresponding equilibrium liquid. This equivalence in aging of glasses formed under different pressures indicates that local packing is the dominant variable governing the glassy dynamics. The fact that pressure densification yields different glass structures is at odds with a model for non-associated materials having dynamic properties exhibited by PMMA, such as density scaling of the relaxation time and isochronal superposition of the relaxation dispersion.

  20. Photoreactive phase conjugation strength in disperse red 1 doped poly(methylmethacrylate) thin films

    NASA Astrophysics Data System (ADS)

    Liu, Sean; Wang, Wei Lin; Fang, Chien Cheng; Huang, Tzer-Hsiang; Hsu, Chia Chen

    2005-01-01

    Near-resonant optical pumping was used to modulate third-order susceptibility χ(3) in disperse red 1 doped poly(methylmethacrylate) thin films. An optically pumped degenerate four-wave mixing (DFWM) experiment was conducted to examine the photoreactive phase conjugation (PC) signals. Experimental results indicated a large anisotropy in PC signals arising from ∣χ3333(3)∣2, and almost isotropic PC signals from ∣χ1331(3)∣2 under s-polarized and p-polarized pump fields. Additionally, a dynamic microscopic model, based on the theory developed by Sekkat et al.[Synth. Met. 54, 373 (1993); J. Phys. Chem. B 106, 12407 (2002); Opt. Commun. 229, 291 (2004)] was presented to describe the observed optical nonlinear responses. Results from the model were generally consistent with those of the optically pumped DFWM experiment.

  1. Residual gentamicin-release from antibiotic-loaded polymethylmethacrylate beads after 5 years of implantation.

    PubMed

    Neut, Daniëlle; van de Belt, Hilbrand; van Horn, Jim R; van der Mei, Henny C; Busscher, Henk J

    2003-05-01

    In infected joint arthroplasty, high local levels of antibiotics are achieved through temporary implantation of non-biodegradable gentamicin-loaded polymethylmethacrylate beads. Despite their antibiotic release, these beads act as a biomaterial surface to which bacteria preferentially adhere, grow and potentially develop antibiotic resistance. In routine clinical practice, these beads are removed after 14 days, but for a variety of reasons, we were confronted with a patient in which these beads were left in situ for 5 years. Retrieval of gentamicin-loaded beads from this patient constituted an exceptional case to study the effects of long-term implantation on potentially colonizing microflora and gentamicin release. Gentamicin-release test revealed residual antibiotic release after being 5 years in situ and extensive microbiological sampling resulted in recovery of a gentamicin-resistant staphylococcal strain from the bead surface. This case emphasizes the importance of developing biodegradable antibiotic-loaded beads as an antibiotic delivery system. Copyright 2003 Elsevier Science Ltd.

  2. Preparation of pure chitosan film using ternary solvents and its super absorbency.

    PubMed

    Wang, Xuejun; Lou, Tao; Zhao, Wenhua; Song, Guojun

    2016-11-20

    Chemical modification and graft copolymerization were commonly adopted to prepare super absorbent materials. However, physical microstructure of pure chitosan film was optimized to improve the water uptake capacity in this study. Chitosan films with micro-nanostructure were prepared by a ternary solvent system. The optimal process parameters are 1% acetic acid water solution: dioxane: dimethyl sulfoxide=90: 2.5: 7.5 (v/v/v) with chitosan concentration at 1.25% (w/v). The water uptake capacity of the chitosan film prepared under the optimal process parameters was 896g/g. The prepared chitosan films also exhibited high water uptake capacity in response to external stimuli such as temperature, pH and salt. This finding may provide another way for improving the water absorbency. The pure chitosan film may find potential applications especially in the fields of hygienic products and biomedicine due to its super water absorbency and nontoxicity. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. Rapidly curable chitosan-PEG hydrogels as tissue adhesives for hemostasis and wound healing.

    PubMed

    Lih, Eugene; Lee, Jung Seok; Park, Kyung Min; Park, Ki Dong

    2012-09-01

    Chitosan-poly(ethylene glycol)-tyramine (CPT) hydrogels were rapidly formed in situ using horseradish peroxidase and hydrogen peroxide to explore their performance as efficient tissue adhesives. A poly(ethylene glycol) modified with tyramine was grafted onto a chitosan backbone to enhance the solubility of the chitosan and to crosslink into three-dimensional networks. The elastic modulus of the hydrogels could be controlled by changing the crosslinking conditions, and the mechanical strength influenced the tissue adhesiveness of the hydrogels. The hydrogels showed the adhesiveness ranging from 3- to 20-fold that of fibrin glue (Greenplast®). The hemostatic ability of the hydrogels was evaluated on the basis that bleeding from liver defects was significantly arrested by the combined effect of the adhesiveness of the hydrogels and the hemostatic property of the chitosan materials. The enzymatic crosslinking method enabled the water-soluble chitosan to rapidly form hydrogels within 5s of an incision into the skin of rats. Histological results demonstrated that the CPT hydrogels showed superior healing effects in the skin incision when compared to suture, fibrin glue and cyanoacrylate. By 2weeks post-implantation, the wound was completely recovered, with a newly formed dermis, due to the presence of the CPT hydrogels in the incision. These results suggest that the in situ curable chitosan hydrogels are very interesting and promising tissue adhesive devices for biomedical applications.

  4. Engineering hydrophobically modified chitosan for enhancing the dispersion of respirable microparticles of levofloxacin.

    PubMed

    Merchant, Zahra; Taylor, Kevin M G; Stapleton, Paul; Razak, Sana A; Kunda, Nitesh; Alfagih, Iman; Sheikh, Khalid; Saleem, Imran Y; Somavarapu, Satyanarayana

    2014-11-01

    The potential of amphiphilic chitosan formed by grafting octanoyl chains on the chitosan backbone for pulmonary delivery of levofloxacin has been studied. The success of polymer synthesis was confirmed using FT-IR and NMR, whilst antimicrobial activity was assessed against Pseudomonas aeruginosa. Highly dispersible dry powders for delivery as aerosols were prepared with different amounts of chitosan and octanoyl chitosan to study the effect of hydrophobic modification and varying concentration of polymer on aerosolization of drug. Powders were prepared by spray-drying from an aqueous solution containing levofloxacin and chitosan/amphiphilic octanoyl chitosan. l-leucine was also used to assess its effect on aerosolization. Following spray-drying, the resultant powders were characterized using scanning electron microscopy, laser diffraction, dynamic light scattering, HPLC, differential scanning calorimetry, thermogravimetric analysis and X-ray powder diffraction. The in vitro aerosolization profile was determined using a Next Generation Impactor, whilst in vitro antimicrobial assessment was performed using MIC assay. Microparticles of chitosan have the property of mucoadhesion leading to potential increased residence time in the pulmonary mucus, making it important to test the toxicity of these formulations. In-vitro cytotoxicity evaluation using MTT assay was performed on A549 cell line to determine the toxicity of formulations and hence feasibility of use. The MTT assay confirmed that the polymers and the formulations were non-cytotoxic. Hydrophobically modifying chitosan showed significantly lower MIC (4-fold) than the commercial chitosan against P. aeruginosa. The powders generated were of suitable aerodynamic size for inhalation having a mass median aerodynamic diameter less than 4.5μm for formulations containing octanoyl chitosan. These highly dispersible powders have minimal moisture adsorption and hence an emitted dose of more than 90% and a fine particle

  5. Effect of the molecular architecture on the thermosensitive properties of chitosan-g-poly(N-vinylcaprolactam).

    PubMed

    Fernández-Quiroz, Daniel; González-Gómez, Álvaro; Lizardi-Mendoza, Jaime; Vázquez-Lasa, Blanca; Goycoolea, Francisco M; San Román, Julio; Argüelles-Monal, Waldo M

    2015-12-10

    A series of thermoresponsive copolymers based on chitosan-g-poly(N-vinylcaprolactam) were synthesized by amidation reaction using 4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium chloride as coupling reagent. The effect of molecular architecture on the thermoresponsive properties of the graft copolymers solutions was studied by varying the chain length of the grafted poly(N-vinylcaprolactam), PVCL, (in the range from 4 to 26 kDa) and the spacing between grafted chains onto the chitosan backbone. The most interesting characteristic of these copolymers is their solubility in water at temperatures below their lower critical solution temperature (LCST). These solutions presented a LCST between 36 and 44 °C, which decreases with the spacing and length of grafted PVCL chains onto the chitosan backbone, in contrast with the limited decrease of the LCST of PVCL above a critical M¯n value around 18 kDa. This behavior offers tangible possibilities for the preparation and application of sensitive bioactive formulations and "smart" drug delivery systems.

  6. A new type of Schwann cell graft transplantation to promote optic nerve regeneration in adult rats.

    PubMed

    Fang, Yuan; Mo, Xiaofen; Guo, Wenyi; Zhang, Meng; Zhang, Peihua; Wang, Yan; Rong, Xianfang; Tian, Jie; Sun, Xinghuai

    2010-12-01

    Like other parts of the central nervous system, the adult mammalian optic nerve is difficult to regenerate after injury. Transplantation of the peripheral nerve or a Schwann cell (SC) graft can promote injured axonal regrowth. We tried to develop a new type of tissue-engineered SC graft that consisted of SCs seeded onto a poly(lactic-co-glycolic acid)/chitosan conduit. Meanwhile, SCs were transfected along the ciliary neurotrophic factor (CNTF) gene in vitro by electroporation to increase their neurotrophic effect. Four weeks after transplantation, GAP-43 labelled regenerating axons were found in the SC grafts, and axons in the CNTF-SC graft were longer than those in the SC graft. Tissue-engineered SC grafts can provide a feasible environment for optic nerve regeneration and may become an alternative for bridging damaged nerves and repairing nerve defects in the future.

  7. Novel High-Viscosity Polyacrylamidated Chitosan for Neural Tissue Engineering: Fabrication of Anisotropic Neurodurable Scaffold via Molecular Disposition of Persulfate-Mediated Polymer Slicing and Complexation

    PubMed Central

    Kumar, Pradeep; Choonara, Yahya E.; du Toit, Lisa C.; Modi, Girish; Naidoo, Dinesh; Pillay, Viness

    2012-01-01

    Macroporous polyacrylamide-grafted-chitosan scaffolds for neural tissue engineering were fabricated with varied synthetic and viscosity profiles. A novel approach and mechanism was utilized for polyacrylamide grafting onto chitosan using potassium persulfate (KPS) mediated degradation of both polymers under a thermally controlled environment. Commercially available high molecular mass polyacrylamide was used instead of the acrylamide monomer for graft copolymerization. This grafting strategy yielded an enhanced grafting efficiency (GE = 92%), grafting ratio (GR = 263%), intrinsic viscosity (IV = 5.231 dL/g) and viscometric average molecular mass (MW = 1.63 × 106 Da) compared with known acrylamide that has a GE = 83%, GR = 178%, IV = 3.901 dL/g and MW = 1.22 × 106 Da. Image processing analysis of SEM images of the newly grafted neurodurable scaffold was undertaken based on the polymer-pore threshold. Attenuated Total Reflectance-FTIR spectral analyses in conjugation with DSC were used for the characterization and comparison of the newly grafted copolymers. Static Lattice Atomistic Simulations were employed to investigate and elucidate the copolymeric assembly and reaction mechanism by exploring the spatial disposition of chitosan and polyacrylamide with respect to the reactional profile of potassium persulfate. Interestingly, potassium persulfate, a peroxide, was found to play a dual role initially degrading the polymers—“polymer slicing”—thereby initiating the formation of free radicals and subsequently leading to synthesis of the high molecular mass polyacrylamide-grafted-chitosan (PAAm-g-CHT)—“polymer complexation”. Furthermore, the applicability of the uniquely grafted scaffold for neural tissue engineering was evaluated via PC12 neuronal cell seeding. The novel PAAm-g-CHT exhibited superior neurocompatibility in terms of cell infiltration owing to the anisotropic porous architecture, high molecular mass mediated robustness, superior

  8. Antimicrobial and inhibitory enzyme activity of N-(benzyl) and quaternary N-(benzyl) chitosan derivatives on plant pathogens.

    PubMed

    Badawy, Mohamed E I; Rabea, Entsar I; Taktak, Nehad E M

    2014-10-13

    Chemical modification of a biopolymer chitosan by introducing quaternary ammonium moieties into the polymer backbone enhances its antimicrobial activity. In the present study, a series of quaternary N-(benzyl) chitosan derivatives were synthesized and characterized by (1)H-NMR, FT-IR and UV spectroscopic techniques. The antimicrobial activity against crop-threatening bacteria Agrobacterium tumefaciens and Erwinia carotovora and fungi Botrytis cinerea, Botryodiplodia theobromae, Fusarium oxysporum and Phytophthora infestans were evaluated. The results proved that the grafting of benzyl moiety or quaternization of the derivatives onto chitosan molecule was successful in inhibiting the microbial growth. Moreover, increase water-solubility of the compounds by quaternization significantly increased the activity against bacteria and fungi. Exocellular enzymes including polygalacturonase (PGase), pectin-lyase (PLase), polyphenol oxidase (PPOase) and cellulase were also affected at 1000 mg/L. These compounds especially quaternary-based chitosan derivatives that have good inhibitory effect should be potentially used as antimicrobial agents in crop protection.

  9. Elucidation on enhanced application of synthesised kojic acid immobilised magnetic and chitosan tri-polyphosphate nanoparticles as antibacterial agents.

    PubMed

    Chaudhary, Jignesh; Lakhawat, Sudarshan; Pathak, Amrendra Nath

    2015-12-01

    Kojic acid (KA) is a secondary metabolite which is secreted by several aspergillus species. It is a multi-functional skeleton from which many derivatives can be synthesised and applied in various areas of biotechnology. KA grafting on synthesised magnetic nanoparticles (MNPs) and chitosan tri-polyphosphate (chitosan-TPP) nanoparticles was successfully done and characterised by Fourier transformation infrared spectroscopy. It was observed that amino propyl triethoxy silane-coated MNPs and chitosan-TPP nanoparticles enhanced the antibacterial activity of KA against both Gram-positive (Staphylococcus aureus) and Gram-negative (Pseudomonas aeruginosa). The organic constitution and significant antibacterial activity of KA-chitosan-TPP nanoparticles can be applicable in the field of medical biotechnology.

  10. Electrospun chitosan/PEDOT nanofibers.

    PubMed

    Kiristi, Melek; Oksuz, Aysegul Uygun; Oksuz, Lutfi; Ulusoy, Seyhan

    2013-10-01

    Plasma-modified chitosan and poly(3,4-ethylenedioxythiophene) were blended to obtain conducting nanofibers with polyvinyl alcohol as a supporting polymer at various volumetric ratios by electrospinning method. Chemical compositions and molecular interactions among nanofiber blend components were determined using Fourier transform infrared spectroscopy (FTIR). The conducting blends containing plasma-modified chitosan resulted in a superior antibacterial activity and thinner fiber formation than those containing chitosan without plasma-modification. The obtained nanofiber diameters of plasma-modified chitosan were in the range of 170 to 200 nm and those obtained from unmodified chitosan were in the range of 190 to 246 nm. The electrical and electrochemical properties of nanofibers were also investigated by four-point probe conductivity and cyclic voltammetry measurements.

  11. Maltose-conjugated chitosans induce macroscopic gelation of pectin solutions at neutral pH.

    PubMed

    Giacomazza, D; Sabatino, M A; Catena, A; Leone, M; San Biagio, P L; Dispenza, C

    2014-12-19

    Injectable polymer scaffolds are particularly attractive for guided tissue growth and drug/cell delivery with minimally invasive intervention. In the present work, "all-polymeric" gelling systems based on pectins and water-soluble maltose-conjugated chitosans (CM) have been developed. Maltose-conjugated chitosan has been synthesized at three different molar ratios, as evaluated by FITR analysis and fluorimetric titration. A thorough rheological characterization of the blends and their parent solutions has been performed. Macroscopic gelation has been achieved by mixing the high esterification degree pectins with CM at higher maltose grafted to chitosan contents. Gels form in a few minutes and reach their full strength in less than two hours. These features encourage their further development as scaffold for tissue engineering.

  12. Cranioplasty by means of molded polymethylmethacrylate prosthetic reconstruction after radical excision of neoplasms of the skull in two dogs.

    PubMed

    Bryant, Karen J; Steinberg, Howard; McAnulty, Jonathan F

    2003-07-01

    Two dogs with osteoma or multilobulated tumor of bone of the skull were treated with large en bloc resections. The resections resulted in exposure of the brain above the horizon line of the remaining calvarium; in 1 dog, the removal of the dorsal orbital rims also exposed both orbits dorsally. Protection of the brain and exposed tissues and restoration of the cosmetic appearance of the skull were attempted by use of molded polymethylmethacrylate prosthetic reconstruction of the calvarium. The technique described involves cranioplasty by use of a preformed molded polymethylmethacrylate implant. Such prosthetic cranioplasty may benefit dogs undergoing radical excision of extensive tumors, and the usefulness and potential complications of its application are discussed.

  13. In vitro study of adhesive polymethylmethacrylate bone cement bonding to cortical bone in maxillofacial surgery.

    PubMed

    Smeets, Ralf; Marx, Rudolf; Kolk, Andreas; Said-Yekta, Sareh; Grosjean, Maurice B; Stoll, Christian; Tinschert, Joachim; Wirtz, Dieter C; Riediger, Dieter; Endres, Kira

    2010-12-01

    In the treatment of midface fractures, the fragments are immobilized using screws and plates for osteosynthesis until reunion has occurred. This method involves drilling holes for the insertion of the screws, which can be associated with additional fracturing of the corresponding bone owing to the complex architecture and thin layers of facial bone. To alleviate this problem, new adhesive techniques for fixing the plates for osteosynthesis have been investigated, mitigating the detrimental effects of screw hole drilling. In the present experimental study, the strength of this adhesive bond and its resistance to hydrolysis were investigated. To determine the adhesive bonding strength, a tension test was implemented. Osteosynthesis plates with screw holes 1.3 mm in diameter were fixed to cortical bone samples of bovine femur using ultraviolet (UV) light-curing polymethylmethacrylate bone cement. To facilitate bonding, the surface of the bone was conditioned with an amphiphilic bonding agent before cementing. UV light curing was implemented using either a conventional UV unit, such as is used in dentistry, or with a specialized UV unit with a limited emission spectrum but high luminosity. Reference control samples were prepared without application of the bone bonding agent. After this procedure, the samples were stored for 1 to 7 days at 37°C submerged in 0.9% saline solution before being subjected to the tension test. Without the bone bonding agent, the bonding strength was 0.2 MPa. The primary average bonding strength at day 0 was 8.5 MPa when cured with the conventional UV unit and 14 MPa for the samples cured with the specialized UV unit. An almost constant average bond strength of 8 and 16 MPa was noted for all samples stored up to 7 days after curing with the conventional and specialized UV unit, respectively. With the development of a new bone bonding agent, a method is now available to promote the bonding between the hydrophilic bone surface and the

  14. Electrostrictive Graft Elastomers

    NASA Technical Reports Server (NTRS)

    Su, Ji (Inventor); Harrison, Joycelyn S. (Inventor); St.Clair, Terry L. (Inventor)

    2003-01-01

    An electrostrictive graft elastomer has a backbone molecule which is a non-crystallizable, flexible macromolecular chain and a grafted polymer forming polar graft moieties with backbone molecules. The polar graft moieties have been rotated by an applied electric field, e.g., into substantial polar alignment. The rotation is sustained until the electric field is removed. In another embodiment, a process for producing strain in an elastomer includes: (a) providing a graft elastomer having a backbone molecule which is a non-crystallizable, flexible macromolecular chain and a grafted polymer forming polar graft moieties with backbone molecules; and (b) applying an electric field to the graft elastomer to rotate the polar graft moieties, e.g., into substantial polar alignment.

  15. Preparation and characterization of PEGylated chitosan nanocapsules as a carrier for pharmaceutical application

    NASA Astrophysics Data System (ADS)

    Najafabadi, Alireza Hassani; Abdouss, Majid; Faghihi, Shahab

    2014-03-01

    A new method to conjugate methoxy polyethylene glycol (mPEG) to C6 position of chitosan under the mild condition is introduced that improves the biocompatibility and water solubility of chitosan. Harsh deprotecting step and several purification cycles are two major disadvantages of the current methods for preparing PEGylated chitosan. In this study, the amine groups at C2 position of chitosan are protected using SDS followed by grafting the PEG. The protecting group of chitosan is simply removed by dialyzing against Tris solution. The chemical structure of the prepared polymer is characterized by FTIR and 1H NMR spectroscopy. Fourier transformed-infrared (FT-IR) and 1H NMR spectra confirmed that the mPEG is successfully grafted to C6 position of chitosan. Prepared methoxy polyethylene glycol (mPEG) is then employed to prepare the nanocapsules for the encapsulation of poor water-soluble drug, propofol. The TEM, AFM, and DLS techniques are used to characterize the prepared nanocapsules size and morphology. The results show a size of about 80 nm with spherical shape for nanocapsules. In vitro drug release is carried out to evaluate the potential of nanocarriers for the intravenous delivery of drugs. The profile of release from formulated nanocapsules is similar to those of commercial lipid emulsion (CLE). In vivo animal sleep-recovery test on rats shows a close similarity between the time of unconsciousness and recovery of righting reflex between nanoparticles and CLE. This study provides an efficient, novel, and easy method for preparing a carrier system that requires less intensive reaction conditions, fewer reaction steps, and less purification steps. In addition, the nanocapsules introduced here could be a promising nano carrier for the delivery of poor water-soluble drugs.

  16. Effects of hydrophobic and hydrophilic modifications on gene delivery of amphiphilic chitosan based nanocarriers.

    PubMed

    Wang, Bingqing; He, Chunbai; Tang, Cui; Yin, Chunhua

    2011-07-01

    The structure-activity relationships between hydrophobic and hydrophilic modification on chitosan and resultant physicochemical properties along with performances in dealing with critical gene delivery barriers were investigated through amphiphilic linoleic acid(LA) and poly (β-malic acid) (PMLA) double grafted chitosan (LMC)/plasmid DNA (pDNA) nanocomplexes. LMC polymers with various LA and PMLA substitution degrees were synthesized and their hydrophilicity/hydrophobicity was characterized. Compared to chitosan, LMC nanoparticles retained the pDNA binding ability at pH 5.5 when they formed nanocomplexes with pDNA encoding enhanced green fluorescence protein (pEGFP) and the resultant complexes showed diameters below 300 nm. Hydrophobic LA and hydrophilic PMLA substitution contributed to suppressed non-specific adsorption, reduced interactions inside LMC/pDNA nanocomplexes, and enhanced pDNA dissociation. However, enzymatic degradation resistance, cell adsorption, and cellular uptake through clathrin-mediated pathway were promoted by hydrophobic LA grafting while being inhibited by hydrophilic PMLA substitution. In vitro transfection assay suggested the optimal LMC/pEGFP nanocomplexes mediated an 8.0-fold improved transfection compared to chitosan/pEGFP nanocomplexes. The 4.2-fold and 2.2-fold higher intramuscular gene expression in mice compared to chitosan/pEGFP and polyethyleneimine (PEI)/pEGFP nanocomplexes further demonstrated the superiority of LMC/pDNA nanocomplexes. Therefore, amphiphilic chitosan derivates with appropriate combination of hydrophobic and hydrophilic modification would be promising gene delivery nanocarriers. Copyright © 2011 Elsevier Ltd. All rights reserved.

  17. Preparation of mono-dispersed silver nanoparticles assisted by chitosan-g-poly(ɛ-caprolactone) micelles and their antimicrobial application

    NASA Astrophysics Data System (ADS)

    Gu, Chunhua; Zhang, Huan; Lang, Meidong

    2014-05-01

    Amphiphilic chitosan-graft-poly(ɛ-caprolactone) (CS-g-PCLs) copolymers were synthesized by a homogeneous coupling method and characterized by 1H NMR, FTIR and ninhydrin assay. The graft copolymers were subsequently self-assembled into micelles, which were measured by DLS and TEM. The particle size of the micelles decreased as the segment grafting fraction was increased. Thereafter, silver nanoparticles were prepared in the presence of chitosan-based micelles under UV irradiation. The molar ratio and radiation time of silver to micelles were optimized with process monitored via UV-vis spectrophotometer. DLS and TEM were used to illustrate the particle structure and size while XRD patterns were applied to characterize the crystal structures of polymer-assisted silver nanoparticles. Films impregnated with silver nanoparticles were conducted with results of strong antimicrobial activities against Escherichia coli and Staphylococcus aureus as model Gram-negative and positive bacteria.

  18. Neodymium: YAG laser damage threshold. A comparison of injection-molded and lathe-cut polymethylmethacrylate intraocular lenses.

    PubMed

    Wilson, S E; Brubaker, R F

    1987-01-01

    The possibility that injection-molded intraocular lenses (IOLs) with imperfections called iridescent clefts could have a decreased threshold to neodymium: YAG (Nd:YAG) laser-induced damage was investigated. Thresholds for Nd:YAG laser-induced damage were determined for injection-molded and lathe-cut polymethylmethacrylate lenses. When aimed at a membrane in contact with a posterior convex surface, the average thresholds were 0.96 +/- 0.18 mJ (Standard deviation [SD]) and 1.80 +/- 0.55 mJ, respectively. The difference was significant at P = 0.001. When injection-molding polymethylmethacrylate was used to make lathe-cut IOLs, very few iridescent clefts were present, and the threshold to Nd:YAG laser-induced damage was 0.94 +/- 0.25 mJ. Iridescent clefts are therefore produced during the injection-molding process but they do not lower the threshold to Nd:YAG laser-induced damage. Rather, the reduced threshold in injection-molded lenses is most probably a result of the polymethylmethacrylate used in their manufacture. Clinically, iridescent clefts in a lens suggest that it has been manufactured by an injection-molding process and that Nd:YAG laser posterior capsulotomy must be performed at the lowest possible energy level to avoid damage.

  19. Development and characterization of an LDPE/chitosan composite antimicrobial film for chilled fish storage.

    PubMed

    Reesha, K V; Panda, Satyen Kumar; Bindu, J; Varghese, T O

    2015-08-01

    An antimicrobial packaging material was developed by uniformly embedding 1, 3 and 5% chitosan (w/w) in low density polyethylene matrix using maleic anhydride grafted LDPE as a compatible agent. The materials were mixed by compounding and blown into monolayer films via blown film extrusion. The developed films showed good barrier properties against oxygen. Characterization of the composite films with Fourier transform infrared spectroscopy revealed that chitosan and LDPE interacted well with each other. Overall migration showed better release of chitosan adduct from the LDPE matrix which enhanced the antibacterial properties of the films. The interaction between the LDPE/CS and maleic anhydride grafted LDPE had a decreasing effect on the tensile strength and heat sealing properties. Investigation on antimicrobial properties of LDPE/CS films showed 85-100% inhibition of Escherichia coli. Efficacy of LDPE/CS films was evaluated by using them as packaging material for chilled storage of Tilapia (Oreochromis mossambicus). Analysis of storage quality indices (peroxide value, free fatty acid, total volatile base nitrogen and aerobic plate count) revealed good antibacterial property and extension of shelf life of Tilapia in the chitosan incorporated novel composite films compared to virgin LDPE film. Copyright © 2015 Elsevier B.V. All rights reserved.

  20. Thermal degradation behaviour of nanoamphiphilic chitosan dispersed poly (lactic acid) bionanocomposite films.

    PubMed

    Pal, Akhilesh Kumar; Katiyar, Vimal

    2017-02-01

    In the present study, nano-amphiphilic chitosan termed as chitosan-grafted-oligo l-lactic acid (CH-g-OLLA), is synthesized by microwave initiated insitu condensation polymerization. The synthesized CH-g-OLLA becomes hydrophobic in nature due to chemical bond formation between chitosan backbone and OLLA chains. Further, CH-g-OLLA (30%) bionanocomposite is used as a nanofiller in poly (lactic acid)/chitosan-grafted-oligo l-lactic acid (PLA/CH-g-OLLA) bionanocomposite films. Surface morphology shows a homogeneous dispersion of CH-g-OLLA in the form of spherical aggregates, which vary in the range of ∼20 to 150nm. Non-isothermal degradation kinetics, proposed by Kissinger, Kissinger-Akahira-Sunose, Flynn-Wall-Ozawa and Augis & Bennett models, are utilized to estimate the activation energies (Ea) for PLA, which are 254.1, 260.2, 257.0 and 259.1kJmol(-1) respectively. The reduction in Ea values of bionanocomposite films may be elucidated by intermolecular distance and enrichment in chain mobility. The evolved gaseous products like hydrocarbons, carbon dioxide, carbon monoxide and cyclic oligomers are successfully identified with TG-FTIR analysis. Copyright © 2016 Elsevier B.V. All rights reserved.

  1. Physicochemical properties and mineralization assessment of porous polymethylmethacrylate cement loaded with hydroxyapatite in simulated body fluid.

    PubMed

    Sa, Yue; Yang, Fang; de Wijn, Joost R; Wang, Yining; Wolke, Joop G C; Jansen, John A

    2016-04-01

    The aim of this study was to evaluate the effect of carboxymethylcellulose (CMC) as a pore generator and hydroxyapatite (HA) as an osteoconductive agent on the physicochemical properties and in-vitro mineralization ability of porous polymethylmethacrylate (PMMA) cement. To this end, various compositions of PMMA cements, which differed in amount of millimeter-sized hydroxyapatite (HA) particles and CMC hydrogel, were prepared and immersed into simulated body fluid (SBF) for 0, 7, 14, 21 and 28 days. It was demonstrated that the incorporation of CMC hydrogel decreased the maximum temperature of cement to the normal body temperature and prolonged the handling time during polymerization. Further, the amount of CMC was responsible for the creation of porosity and interconnectivity, which in turn determined the final mechanical properties of cements. The loaded HA particles enhanced the potential bioactivity of cement for bone ingrowth. Albeit different amount of HA particles influenced their final exposures on the surface of cured cement, all of the three amounts of HA did not weaken the final mechanical properties of cements. The data here suggests that the HA particle loaded porous PMMA cement can serve as the promising candidate for bone reconstruction. Copyright © 2015 Elsevier B.V. All rights reserved.

  2. Polymethylmethacrylate (PMMA) Material Test Results for the Capillary Flow Experiments (CFE)

    NASA Technical Reports Server (NTRS)

    Lerch, Bradley A.; Thesken, John C.; Bunnell, Charles T.

    2007-01-01

    In support of the Capillary Flow Experiments (CFE) program, several polymethylmethacrylate (PMMA) flight vessels were constructed. Some vessels used a multipiece design, which was chemically welded together. Due to questions regarding the effects of the experiment fluid (silicone oil) on the weld integrity, a series of tests were conducted to provide evidence of the adequacy of the current vessel design. Tensile tests were conducted on PMMA samples that were both in the as-received condition, and also aged in air or oil for up to 8 weeks. Both welded and unwelded samples were examined. Fracture of the joints was studied using notched tensile specimens and Brazilian disk tests. Results showed that aging had no effect on tensile properties. While the welded samples were weaker than the base parent material, the weld strength was found to be further degraded by bubbles in the weld zone. Finally a fracture analysis using the worst-case fracture conditions of the vessel was performed, and the vessel design was found to have a factor of three safety margin.

  3. Contact angle analysis on polymethylmethacrylate and commercial wax by using an environmental scanning electron microscope.

    PubMed

    Brugnara, Marco; Della Volpe, Claudio; Siboni, Stefano; Zeni, Dario

    2006-01-01

    The environmental scanning electron microscope (ESEM) represents one of the most exciting breakthroughs in electron microscopy since the invention of the electron microscope. Its ability to observe uncoated and hydrated samples enhances the possibility for investigating the wettability of surfaces at a microscopic level; by varying the relative vapour pressure or the temperature inside the chamber, it is possible to condense water drops on a micron scale. A large problem in measuring contact angles by ESEM is that the observation angle is not parallel or perpendicular to the surface; thus, the study of the droplets profile using the common algorithms such as spherical approximation or axisymmetric drop shape analysis (ADSA) is not possible, because only a spherical cap shape is commonly observed. In this paper we provide a useful mathematical model to calculate the real contact angle from the initial images. Initially, some simulated spherical caps with different contact and observation angles were created by an appropriate graphic package in order to test the mathematical model. Some real drops obtained by ESEM on wax and polymethylmethacrylate (PMMA) were then studied and the results compared with contact angles measured by common methods on the same materials.

  4. Ultrasonic Characterization of the Curing Process of Polymethylmethacrylate-based Bone Cement Modified with Hydroxyapatite

    NASA Astrophysics Data System (ADS)

    Viano, Ann; Auwarter, Julie; Hoffmeister, Brent; Rho, Jae-Young

    2000-03-01

    The use of polymethylmethacrylate (PMMA)-based bone cement for implantation of metallic prostheses is becoming increasingly common. Failure of a cemented prosthesis often occurs when there is weak bonding at the bone/cement or cement/metal interface. The addition of hydroxyapatite (HA) particles, a synthetically produced version of the natural mineral in bone, may improve the adhesion by promoting bone growth into the cement itself. The curing time of PMMA bone cement determines the speed of implant insertion, which can affect the mechanical strength of the cement. Pure PMMA has a well-characterized curing time of 9-12 minutes, depending on environmental factors such as temperature and humidity. By measuring the propagation of ultrasonic pulses through a sample of bone cement, the curing process can be monitored. As the material hardens, the velocity of an ultrasonic pulse increases, and the attenuation decreases. These parameters were measured as a function of time for PMMA mixed with 0, 10 and 30investigation of the curing process as a function of hydroxyapatite concentration.

  5. The elution of colistimethate sodium from polymethylmethacrylate and calcium phosphate cement beads.

    PubMed

    Waterman, Paige; Barber, Melissa; Weintrob, Amy C; VanBrakle, Regina; Howard, Robin; Kozar, Michael P; Andersen, Romney; Wortmann, Glenn

    2012-06-01

    Gram-negative bacilli resistance to all antibiotics, except for colistimethate sodium (CMS), is an emerging healthcare concern. Incorporating CMS into orthopedic cement to treat bone and soft-tissue infections due to these bacteria is attractive, but the data regarding the elution of CMS from cement are conflicting. The in vitro analysis of the elution of CMS from polymethylmethacrylate (PMMA) and calcium phosphate (CP) cement beads is reported. PMMA and CP beads containing CMS were incubated in phosphate-buffered saline and the eluate sampled at sequential time points. The inhibition of the growth of a strain of Acinetobacter baumannii complex by the eluate was measured by disk diffusion and microbroth dilution assays, and the presence of CMS in the eluate was measured by mass spectroscopy. Bacterial growth was inhibited by the eluate from both PMMA and CP beads. Mass spectroscopy demonstrated greater elution of CMS from CP beads than PMMA beads. The dose of CMS in PMMA beads was limited by failure of bead integrity. CMS elutes from both CP and PMMA beads in amounts sufficient to inhibit bacterial growth in vitro. The clinical implications of these findings require further study.

  6. Characterization and performance of injection molded poly(methylmethacrylate) microchips for capillary electrophoresis.

    PubMed

    Nikcevic, Irena; Lee, Se Hwan; Piruska, Aigars; Ahn, Chong H; Ridgway, Thomas H; Limbach, Patrick A; Wehmeyer, K R; Heineman, William R; Seliskar, Carl J

    2007-06-22

    Injection molded poly(methylmethacrylate) (IM-PMMA), chips were evaluated as potential candidates for capillary electrophoresis disposable chip applications. Mass production and usage of plastic microchips depends on chip-to-chip reproducibility and on analysis accuracy. Several important properties of IM-PMMA chips were considered: fabrication quality evaluated by environmental scanning electron microscope imaging, surface quality measurements, selected thermal/electrical properties as indicated by measurement of the current versus applied voltage (I-V) characteristic and the influence of channel surface treatments. Electroosmotic flow was also evaluated for untreated and O2 reactive ion etching (RIE) treated surface microchips. The performance characteristics of single lane plastic microchip capillary electrophoresis (MCE) separations were evaluated using a mixture of two dyes-fluorescein (FL) and fluorescein isothiocyanate (FITC). To overcome non-wettability of the native IM-PMMA surface, a modifier, polyethylene oxide was added to the buffer as a dynamic coating. Chip performance reproducibility was studied for chips with and without surface modification via the process of RIE with O2 and by varying the hole position for the reservoir in the cover plate or on the pattern side of the chip. Additionally, the importance of reconditioning steps to achieve optimal performance reproducibility was also examined. It was found that more reproducible quantitative results were obtained when normalized values of migration time, peak area and peak height of FL and FITC were used instead of actual measured parameters.

  7. Possible migration and histopathological analysis of injections of polymethylmethacrylate in wistar rats.

    PubMed

    Neves, Rodrigo d'Eça; Herdt, Marcello Alberton; Wohlgemuth, Felipe Barbieri; Ely, Jorge Bins; de Vasconcellos, Zulmar Antonio Accioli; Bastos, José Caldeira Ferreira; d'Acampora, Armando José

    2012-01-01

    Objective. To evaluate the possible migration of polymethylmethacrylate after injections in various corporal compartments of Wistar rats. Methods. The experimental work consisted in the injection of PMMA in corporal compartments for later histopathological analysis of the locations of implants and of distant filtering organs. The dose applied in each implant was of 0.2 mL. The animals were divided into groups according to the location of the implant realized: group GB had intradermic injections in the glabella. Group SD had subdermal injections in dorsal subcutaneous tissue cells. Group IP had intraperitoneal injections in the abdomen. Group PD had intramuscular injections in the right rear leg. The rats were sacrificed 30 days after realization of the implants and tissue samples from the lung, liver, spleen, and kidney, and locations of implantation were removed for histopathological analysis. Results. Characteristic microspheres that were compatible with the presence of PMMA in any of the histological slides analyzed were not observed. One animal had an amorphous exogenous substance, with a histiocytic reaction. Twelve of the 16 lungs analyzed had locations of intraalveolar hemorrhaging. Two animals had nonspecific spleen alterations. Conclusion. The histopathological analysis of this study found no PMMA microspheres in any of the tissues analyzed.

  8. Patterning of ultrathin polymethylmethacrylate films by in-situ photodirecting of the Marangoni flow

    NASA Astrophysics Data System (ADS)

    Elashnikov, Roman; Fitl, Premysl; Svorcik, Vaclav; Lyutakov, Oleksiy

    2017-02-01

    Laser heating and Marangoni flow result in the formation of surface structures with different geometries and shape on thin polymer films. By laser beam irradiation combined with a sample movement the solid polymethylmethacrylate (PMMA) films are heated and undergo phase transition which leads to a material flow. Since the laser beam has a non-linear distribution of energy, the PMMA film is heated inhomogeneously and a surface tension gradient in a lateral direction is introduced. During this procedure additional phenomena such as "reversible" or cyclic polymer flow also take place. The careful choice of experimental conditions enables the preparation of patterns with sophisticated geometries and with hierarchical pattern organization. Depending on initial PMMA film thickness and speed of the sample movement line arrays are created, which can subsequently be transformed into the crimped lines or system of circular holes. In addition, the introduction of a constant acceleration in the sample movement or a laser beam distortion enables the preparation of regularly crimped lines, ordered hexagonal holes or overlapped plates.

  9. Near Surface Vapor Bubble Layers in Buoyant Low Stretch Burning of Polymethylmethacrylate

    NASA Technical Reports Server (NTRS)

    Olson, Sandra L.; Tien, J. S.

    1999-01-01

    Large-scale buoyant low stretch stagnation point diffusion flames over solid fuel (polymethylmethacrylate) were studied for a range of aerodynamic stretch rates of 2-12/ sec which are of the same order as spacecraft ventilation-induced stretch in a microgravity environment. An extensive layer of polymer material above the glass transition temperature is observed. Unique phenomena associated with this extensive glass layer included substantial swelling of the burning surface, in-depth bubble formation, and migration and/or elongation of the bubbles normal to the hot surface. The bubble layer acted to insulate the polymer surface by reducing the effective conductivity of the solid. The reduced in-depth conduction stabilized the flame for longer than expected from theory neglecting the bubble layer. While buoyancy acts to move the bubbles deeper into the molten polymer, thermocapillary forces and surface regression both act to bring the bubbles to the burning surface. Bubble layers may thus be very important in low gravity (low stretch) burning of materials. As bubbles reached the burning surface, monomer fuel vapors jetted from the surface, enhancing burning by entraining ambient air flow. Popping of these bubbles at the surface can expel burning droplets of the molten material, which may increase the fire propagation hazards at low stretch rates.

  10. Deep proton writing with 12 MeV protons for rapid prototyping of microstructures in polymethylmethacrylate

    NASA Astrophysics Data System (ADS)

    Ebraert, Evert; Gökçe, Berkcan; Van Vlierberghe, Sandra; Vervaeke, Michael; Meyer, Pascal; Guttmann, Markus; Dubruel, Peter; Thienpont, Hugo; Van Erps, Jürgen

    2016-10-01

    Deep proton writing (DPW) is a fabrication technology developed for the rapid prototyping of polymer microstructures. We use polymethylmethacrylate (PMMA) substrates, which act as a positive resist, for irradiation with a collimated 12-MeV energy proton beam. Using 12 MeV enables the irradiation of increasingly thick PMMA substrates with less conicity of the sidewalls compared to the lower energies used in previous work. A microhole of 47.7 μm diameter over a depth of 1 mm is achieved, leading to a maximum aspect ratio of 21∶1. The sidewalls of the irradiated structures show a slightly conical shape and their root-mean-square surface roughness is lower than 50 nm averaged over 72 measured areas of 56 μm×44 μm. This means that DPW components have optical surface quality sidewalls for wavelengths larger than 400 nm. Based on the trade-off among the sidewall roughness, conicity, and the development time, we determine that the optimal proton fluence for 12-MeV DPW in PMMA is 7.75×106 μm-2. Finally, we discuss some high aspect ratio microstructures with optical surface quality that were created with DPW to be used for a myriad of applications, such as micromirrors, microlenses, optofluidic devices, and high-precision alignment structures for single-mode optical fiber connectors.

  11. Impregnation of glass fibres with polymethylmethacrylate using a powder-coating method

    NASA Astrophysics Data System (ADS)

    Vallittu, Pekka K.

    1995-01-01

    The aim of this study was to evaluate the usefulness of a powder-coating method to impregnate glass fibres with polymethylmethacrylate (PMMA) for dental purposes. The continuous unidirectional E-glass fibres, the surface of which had been treated with precured silane, were powder-coated with spherical PMMA particles. Before the powder-coated prepregs were used, the incorporated PMMA powder was dissolved with methylmethacrylate monomer. The degree of impregnation of the polymerized composite was determined with a scanning electron microscope. The results revealed that the mean degree of impregnation varied from 0.87 to 0.92, being lower in the heat-cured PMMA group (which simulated fabrication of a new denture), and higher in the autopolymerizing group (which simulated the repair of a fractured denture). The means between the two groups did not, however, differ significantly ( p=0.249). The results suggest that, even though the method has some shortcomings in terms of dental laboratory technology, the powder-coating method can be used to fabricate or repair acrylic resin-based dentures.

  12. A prospective study of non-surgical primary rhinoplasty using a polymethylmethacrylate injectable implant.

    PubMed

    Rivkin, Alexander

    2014-03-01

    Nonsurgical rhinoplasty involves the use of injectable fillers to improve the contours of the nose. It has become a widely practiced procedure since this author first popularized it in 2003. The use of permanent fillers in nonsurgical rhinoplasty has not been well documented, especially in this country. To demonstrate the safety and effectiveness of a polymethylmethacrylate (PMMA)-based filler for nonsurgical rhinoplasty. Eligible subjects underwent up to three injection sessions with a commercially available PMMA product and were followed for 1 year. Efficacy was assessed according to evaluator grading of subjects and digital image analysis of standardized photographs. Nineteen subjects were enrolled and followed to conclusion. Average improvement in global score was more than one point observed on day 90 and lasting through 1 year. Eight of 10 subjects showed improvement according to digital image analysis at 1 year. Subject satisfaction was high throughout the study. Adverse events were minimal and well tolerated. Filler rhinoplasty using a PMMA-based injectable filler is safe and effective. This is the first study documenting the use of PMMA for this indication. Longer-term follow-up is needed to demonstrate persistence of improvement. © 2013 by the American Society for Dermatologic Surgery, Inc. Published by Wiley Periodicals, Inc.

  13. Synergistic toxicity of gentamicin- and nanosilver-doped polymethylmethacrylate bone cement on primary human osteoclasts.

    PubMed

    Pauksch, Linda; Franke, Jörg; Schnettler, Reinhard; Lips, Katrin S

    2014-01-01

    Bacterial colonization of implant surfaces is a feared complication in surgery and orthopedics. Due to the increasing number of periprosthetic infections caused by multidrug-resistant microorganisms, new antibacterial coatings for biomaterials must be developed. The excellent antibacterial properties of silver nanoparticles (AgNPs) against multidrug-resistant bacteria, for example, have been repeatedly described. For this reason, we tested a nanosilver-doped polymethylmethacrylate (PMMA) bone cement and a nanosilver-coated titanium alloy regarding their influence on osteoclastogenesis of primary human peripheral blood mononuclear cells. Both implant variants did not inhibit osteoclast differentiation. Excellent cell attachment and unaltered podosomal structures were confirmed. Additionally, no induction of oxidative or endoplasmic reticulum stress could be observed. However, PMMA loaded with gentamicin and nanosilver inhibited preosteoclast fusion and further osteoclastogenesis. The material also led to decreased clathrin-dependent endocytosis as well as decreased levels of endoplasmic reticulum stress. Therefore, biomaterial functionalization with AgNPs did not disturb osteoclastogenesis, while addition of gentamicin reduced the cytocompatibility of nanosilver-doped materials towards human osteoclasts.

  14. Specifications of nanosecond laser ablation with solid targets, aluminum, silicon rubber, and polymethylmethacrylate (PMMA)

    NASA Astrophysics Data System (ADS)

    Morshedian, Nader

    2017-09-01

    The ablation parameters such as threshold fluence, etch depth, ablation rate and the effect of material targets were investigated under the interaction of laser pulse with low intensity. The parameters of the laser system are: laser pulse energy in the range of 110-140 mJ, wavelength 1064 nm and pulse duration 20 ns. By macroscopic estimation of the outward images of the ablation and data obtained, we can conclude that the photothermal and photoionization processes have more influence for aluminum ablation. In contrast, for polymer samples, from the macroscopic observation of the border pattern at the irradiated spot, and also the data obtained from the experiment results, we deduce that both chemical change due to heating and photochemical dissociation were effective mechanisms of ablation. However, concerning the two polymer samples, apart from considering the same theoretical ablation model, it is conceived that the photomehanical specifications of PMMA are involved in the ablation parameters. The threshold fluence for an ablation rate of 30 laser shots were obtained as 12.4, 24.64, and 11.71 J cm-2, for aluminum, silicon rubber and polymethylmethacrylate (PMMA) respectively. The ablation rate is exponentially decreased by the laser-shot number, especially for aluminum. Furthermore, the etch depth after 30 laser shots was measured as 180, 630 and 870 μm, for aluminum, silicon rubber and PMMA, respectively.

  15. Enhanced osteointegration of poly(methylmethacrylate) bone cements by incorporating strontium-containing borate bioactive glass.

    PubMed

    Cui, Xu; Huang, Chengcheng; Zhang, Meng; Ruan, Changshun; Peng, Songlin; Li, Li; Liu, Wenlong; Wang, Ting; Li, Bing; Huang, Wenhai; Rahaman, Mohamed N; Lu, William W; Pan, Haobo

    2017-06-01

    Although poly(methylmethacrylate) (PMMA) cements are widely used in orthopaedics, they have numerous drawbacks. This study aimed to improve their bioactivity and osseointegration by incorporating strontium-containing borate bioactive glass (SrBG) as the reinforcement phase and bioactive filler of PMMA cement. The prepared SrBG/PMMA composite cements showed significantly decreased polymerization temperature when compared with PMMA and retained properties of appropriate setting time and high mechanical strength. The bioactivity of SrBG/PMMA composite cements was confirmed in vitro, evidenced by ion release (Ca, P, B and Sr) from SrBG particles. The cellular responses of MC3T3-E1 cells in vitro demonstrated that SrBG incorporation could promote adhesion, migration, proliferation and collagen secretion of cells. Furthermore, our in vivo investigation revealed that SrBG/PMMA composite cements presented better osseointegration than PMMA bone cement. SrBG in the composite cement could stimulate new-bone formation around the interface between the composite cement and host bone at eight and 12 weeks post-implantation, whereas PMMA bone cement only stimulated development of an intervening connective tissue layer. Consequently, the SrBG/PMMA composite cement may be a better alternative to PMMA cement in clinical applications and has promising orthopaedic applications by minimal invasive surgery. © 2017 The Author(s).

  16. Evaluation of antibiotic releasing porous polymethylmethacrylate space maintainers in an infected composite tissue defect model.

    PubMed

    Spicer, Patrick P; Shah, Sarita R; Henslee, Allan M; Watson, Brendan M; Kinard, Lucas A; Kretlow, James D; Bevil, Kristin; Kattchee, Lauren; Bennett, George N; Demian, Nagi; Mende, Katrin; Murray, Clinton K; Jansen, John A; Wong, Mark E; Mikos, Antonios G; Kasper, F Kurtis

    2013-11-01

    This study evaluated the in vitro and in vivo performance of antibiotic-releasing porous polymethylmethacrylate (PMMA)-based space maintainers comprising a gelatin hydrogel porogen and a poly(dl-lactic-co-glycolic acid) (PLGA) particulate carrier for antibiotic delivery. Colistin was released in vitro from either gelatin or PLGA microparticle loaded PMMA constructs, with gelatin-loaded constructs releasing colistin over approximately 7 days and PLGA microparticle-loaded constructs releasing colistin for up to 8 weeks. Three formulations with either burst release or extended release at different doses were tested in a rabbit mandibular defect inoculated with Acinetobacter baumannii (2×10(7) colony forming units ml(-1)). In addition, one material control that released antibiotic but was not inoculated with A. baumannii was tested. A. baumannii was not detectable in any animal after 12 weeks on culture of the defect, saliva, or blood. Defects with high dose extended release implants had greater soft tissue healing compared with defects with burst release implants, with 8 of 10 animals showing healed mucosae compared with 2 of 10 respectively. Extended release of locally delivered colistin via a PLGA microparticle carrier improved soft tissue healing compared with implants with burst release of colistin from a gelatin carrier. Copyright © 2013 Acta Materialia Inc. All rights reserved.

  17. Antibiotic-releasing porous polymethylmethacrylate/gelatin/antibiotic constructs for craniofacial tissue engineering.

    PubMed

    Shi, Meng; Kretlow, James D; Spicer, Patrick P; Tabata, Yasuhiko; Demian, Nagi; Wong, Mark E; Kasper, F Kurtis; Mikos, Antonios G

    2011-05-30

    An antibiotic-releasing porous polymethylmethacrylate (PMMA) construct was developed to maintain the bony space and prime the wound site in the initial step of a two-stage regenerative medicine approach toward reconstructing significant bony or composite craniofacial tissue defects. Porous PMMA constructs incorporating gelatin microparticles (GMPs) were fabricated by the sequential assembly of GMPs, the antibiotic colistin, and a clinically used bone cement formulation of PMMA powder and methylmethacrylate liquid. PMMA/gelatin/antibiotic constructs with varying gelatin incorporation and drug content were investigated to elucidate the relationship between material composition and construct properties (porosity and drug release kinetics). The porosity of PMMA/gelatin/antibiotic constructs ranged between 7.6±1.8% and 38.4±1.4% depending on the amount of gelatin incorporated and the drug solution added for gelatin swelling. The constructs released colistin over 10 or 14 days with an average release rate per day above 10 μg/ml. The porosity and in vitro colistin release kinetics of PMMA/gelatin/antibiotic constructs were tuned by varying the material composition and fabrication parameters. This study demonstrates the potential of gelatin-incorporating PMMA constructs as a functional space maintainer for both promoting tissue healing/coverage and addressing local infections, enabling better long-term success of the definitive regenerated tissue construct. Copyright © 2011 Elsevier B.V. All rights reserved.

  18. Fluoride release, recharge and flexural properties of polymethylmethacrylate containing fluoridated glass fillers.

    PubMed

    Al-Bakri, I A; Swain, M V; Naoum, S J; Al-Omari, W M; Martin, E; Ellakwa, A

    2014-06-01

    The purpose of this study was to investigate the effect of fluoridated glass fillers on fluoride release, recharge and the flexural properties of modified polymethylmethacrylate (PMMA). Specimens of PMMA denture base material with various loading of fluoridated glass fillers (0%, 1%, 2.5%, 5% and 10% by weight) were prepared. Flexural properties were evaluated on rectangular specimens (n = 10) aged in deionized water after 24 hours, 1 and 3 months. Disc specimens (n = 10) were aged for 43 days in deionized water and lactic acid (pH 4.0) and fluoride release was measured at numerous intervals. After ageing, specimens were recharged and fluoride re-release was recorded at 1, 3 and 7 days after recharge. Samples containing 2.5%, 5% and 10% glass fillers showed significantly (p < 0.05) greater levels of fluoride release compared with the control and 1% glass fillers specimens. All experimental specimens exhibited fluoride release in both media. The flexural strength of specimens decreased in proportion to the percentage filler inclusion with the modulus of elasticity values remaining within ISO Standard 1567. The modified PMMA with fluoridated glass fillers has the ability to release and re-release fluoride ion. Flexural strength decreased as glass filler uploading increased. © 2014 Australian Dental Association.

  19. Customized Cranioplasty Implants Using Three-Dimensional Printers and Polymethyl-Methacrylate Casting

    PubMed Central

    Kim, Bum-Joon; Hong, Ki-Sun; Park, Kyung-Jae; Park, Dong-Hyuk; Chung, Yong-Gu

    2012-01-01

    Objective The prefabrication of customized cranioplastic implants has been introduced to overcome the difficulties of intra-operative implant molding. The authors present a new technique, which consists of the prefabrication of implant molds using three-dimensional (3D) printers and polymethyl-methacrylate (PMMA) casting. Methods A total of 16 patients with large skull defects (>100 cm2) underwent cranioplasty between November 2009 and April 2011. For unilateral cranial defects, 3D images of the skull were obtained from preoperative axial 1-mm spiral computed tomography (CT) scans. The image of the implant was generated by a digital subtraction mirror-imaging process using the normal side of the cranium as a model. For bilateral cranial defects, precraniectomy routine spiral CT scan data were merged with postcraniectomy 3D CT images following a smoothing process. Prefabrication of the mold was performed by the 3D printer. Intraoperatively, the PMMA implant was created with the prefabricated mold, and fit into the cranial defect. Results The median operation time was 184.36±26.07 minutes. Postoperative CT scans showed excellent restoration of the symmetrical contours and curvature of the cranium in all cases. The median follow-up period was 23 months (range, 14-28 months). Postoperative infection was developed in one case (6.2%) who had an open wound defect previously. Conclusion Customized cranioplasty PMMA implants using 3D printer may be a useful technique for the reconstruction of various cranial defects. PMID:23346326

  20. The use of polymethyl-methacrylate (Artecoll) as an adjunct to facial reconstruction

    PubMed Central

    Mok, David; Schwarz, Jorge

    2004-01-01

    BACKGROUND: Injectable polymethyl-methacrylate (PMMA) microspheres, or Artecoll, has been used for the last few years in aesthetic surgery as long-term tissue filler for the correction of wrinkles and for lip augmentation. This paper presents three cases of the use of PMMA microsphere injection for reconstructive patients with defects of varying etiologies. These cases provide examples of a novel adjunct to the repertoire of the reconstructive surgeon. OBJECTIVES: To evaluate the effectiveness (short- and long-term) of PMMA injection for the correction of small soft tissue defects of the face. METHODS: Three case histories are presented. They include the origin of the defect; previous reconstructions of the defect; and area, volume, timing and technical particularities of PMMA administration. RESULTS: All three cases showed improvement of the defect with the PMMA injection with respect to both objective evidence and patient satisfaction. The improvements can still be seen after several years. CONCLUSIONS: PMMA microsphere injection can be effectively used to correct selected small facial defects in reconstructive cases and the results are long lasting. PMID:24115873

  1. Bone response to porous polymethylmethacrylate cement loaded with hydroxyapatite particles in a rabbit mandibular model.

    PubMed

    Sa, Yue; Yu, Na; Wolke, Joop G C; Chanchareonsook, Nattharee; Goh, Bee Tin; Wang, Yining; Yang, Fang; Jansen, John A

    2017-04-03

    The aim of the current study was to evaluate bone formation and tissue response to porous polymethylmethacrylate (PMMA) cement with or without hydroxyapatite (HA) in a rabbit mandibular model. Therefore, fourteen New Zealand white rabbits were randomly divided into two groups of seven according to the designed study end points of 4 and 12 weeks. For each rabbit, two decorticated defects (6 mm in height and 10 mm in width for each) were prepared at both sides of the mandible. Subsequently, the defects were filled with respectively porous PMMA and porous PMMA-HA cement. After reaching the designated implantation period, the rabbits were euthanized and the mandibles were retrieved for histological analysis. Results showed that both porous PMMA and porous PMMA-HA supported bone repair. Neither of the bone cements caused significant inflammation to nerve or other surrounding tissues. After implantation of 12 weeks, majority of the porosity was filled with newly formed bone for both cements, which supports the concept that a porous structure within PMMA can enhance bone ingrowth. Histomorphometrical evaluation, using histological grading scales, demonstrated that, at both implantation times, the presence of HA in the PMMA enhanced bone formation. Bone was always in direct contact with the HA particles, while intervening fibrous tissue was present at the PMMA-bone interface. On the basis of results, it was concluded that injectable porous PMMA-HA cement might be a good candidate for craniofacial bone repair, which should be further evaluated in a more clinically relevant large animal model.

  2. Sterilization by gamma radiation of antibiotic impregnated polymethylmethacrylate and plaster of Paris beads. A pilot study.

    PubMed

    Trencart, P; Elce, Y A; Rodriguez Batista, E; Michaud, G

    2014-01-01

    Ethylene oxide is currently recommended for sterilization of antibiotic impregnated beads; however this method carries health risks to personnel and is becoming less available. To perform a pilot study of the effect of radiation for sterilization of polymethylmethacrylate (PMMA) and plaster of Paris (POP) beads impregnated with amikacin, enrofloxacin, and ceftiofur. Radiation would effectively sterilize the beads without affecting the efficacy of the antibiotic. Beads of PMMA and POP were prepared in a clean but non-sterile manner with one of the three antibiotics (amikacin, enrofloxacin, ceftiofur) or no antibiotic. Beads were then exposed to radiation for a total dose of 0 kiloGray (kGy), 10 kGy and 25 kGy. Beads were incubated on Mueller-Hinton agar plates seeded with Escherichia coli, Staphylococcus aureus or Pseudomonas aeruginosa for 24 hours or cultured in brain-heart infusion broth for 48 hours. Zones of inhibition were measured on the agar plates and statistics were performed on the diameters of the zones of inhibition using an analysis of variance. There were no differences in the diameters of inhibition for all levels of radiation for all PMMA beads. The same was true with POP beads with the exception of enrofloxacin which had a significantly decreased zone of inhibition with increased levels of radiation, though the clinical significance of this finding was not assessed. Only beads without antibiotics and not exposed to radiation had bacterial growth. Radiation may be an effective method of sterilization for antibiotic impregnated beads.

  3. Ablation of bone and polymethylmethacrylate by an XeCl (308 nm) excimer laser

    SciTech Connect

    Yow, L.; Nelson, J.S.; Berns, M.W.

    1989-01-01

    One of the main problems in orthopaedics is the surgical removal of hard substances, such as bone and polymethylmethacrylate (PMMA). Such materials are often very difficult to remove without mechanical trauma to the remaining tissue. This study investigated the feasibility of the ultraviolet 308 nm excimer laser in the ablation of these materials. The beam was delivered through a 1 mm-diameter fiber optic at 40 Hz with energy densities at the target surface of 20-80 J/cm2 per pulse. The goal of the study was to establish the ideal dosimetry for removing bone and PMMA with minimum trauma to the adjacent tissue. Histology revealed that the 308 nm laser effectively removed bone leaving a thermal damage zone of only 2-3 microns in the remaining tissue. Increasing the energy per pulse gave correspondingly larger and deeper cuts with increasing zones of thermal damage. The excimer laser was also effective in the ablation of PMMA, creating craters in the substrate with a thermal damage zone of 10-40 microns. The debris from both substrates was evaluated.

  4. Encapsulation of testosterone by chitosan nanoparticles.

    PubMed

    Chanphai, P; Tajmir-Riahi, H A

    2017-05-01

    The loading of testosterone by chitosan nanoparticles was investigated, using multiple spectroscopic methods, thermodynamic analysis, TEM images and modeling. Thermodynamic parameters showed testosterone-chitosan bindings occur mainly via H-bonding and van der Waals contacts. As polymer size increased more stable steroid-chitosan conjugates formed and hydrophobic contact was also observed. The loading efficacy of testosterone-nanocarrier was 40-55% and increased as chitosan size increased. Testosterone encapsulation markedly alters chitosan morphology. Chitosan nanoparticles are capable of transporting testosterone in vitro. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. Scaffolds based bone tissue engineering: the role of chitosan.

    PubMed

    Costa-Pinto, Ana Rita; Reis, Rui L; Neves, Nuno M

    2011-10-01

    As life expectancy increases, malfunction or loss of tissue caused by injury or disease leads to reduced quality of life in many patients at significant socioeconomic cost. Even though major progress has been made in the field of bone tissue engineering, present therapies, such as bone grafts, still have limitations. Current research on biodegradable polymers is emerging, combining these structures with osteogenic cells, as an alternative to autologous bone grafts. Different types of biodegradable materials have been proposed for the preparation of three-dimensional porous scaffolds for bone tissue engineering. Among them, natural polymers are one of the most attractive options, mainly due to their similarities with extracellular matrix, chemical versatility, good biological performance, and inherent cellular interactions. In this review, special attention is given to chitosan as a biomaterial for bone tissue engineering applications. An extensive literature survey was performed on the preparation of chitosan scaffolds and their in vitro biological performance as well as their potential to facilitate in vivo bone regeneration. The present review also aims to offer the reader a general overview of all components needed to engineer new bone tissue. It gives a brief background on bone biology, followed by an explanation of all components in bone tissue engineering, as well as describing different tissue engineering strategies. Moreover, also discussed are the typical models used to evaluate in vitro functionality of a tissue-engineered construct and in vivo models to assess the potential to regenerate bone tissue are discussed.

  6. Chitosan-g-MPEG-modified alginate/chitosan hydrogel microcapsules: a quantitative study of the effect of polymer architecture on the resistance to protein adsorption.

    PubMed

    Zheng, Jia N; Xie, Hong G; Yu, Wei T; Liu, Xiu D; Xie, Wei Y; Zhu, Jing; Ma, Xiao J

    2010-11-16

    The chemical modification of the alginate/chitosan/alginate (ACA) hydrogel microcapsule with methoxy poly(ethylene glycol) (MPEG) was investigated to reduce nonspecific protein adsorption and improve biocompatibility in vivo. The graft copolymer chitosan-g-MPEG (CS-g-MPEG) was synthesized, and then alginate/chitosan/alginate/CS-g-MPEG (ACAC(PEG)) multilayer hydrogel microcapsules were fabricated by the layer-by-layer (LBL) polyelectrolyte self-assembly method. A quantitative study of the modification was carried out by the gel permeation chromatography (GPC) technique, and protein adsorption on the modified microcapsules was also investigated. The results showed that the apparent graft density of the MPEG side chain on the microcapsules decreased with increases in the degree of substitution (DS) and the MPEG chain length. During the binding process, the apparent graft density of CS-g-MPEG showed rapid growth-plateau-rapid growth behavior. CS-g-MPEG was not only bound to the surface but also penetrated a certain depth into the microcapsule membranes. The copolymers that penetrated the microcapsules made a smaller contribution to protein repulsion than did the copolymers on the surfaces of the microcapsules. The protein repulsion ability decreased with the increase in DS from 7 to 29% with the same chain length of MPEG 2K. CS-g-MPEG with MPEG 2K was more effective at protein repulsion than CS-g-MPEG with MPEG 550, having a similar DS below 20%. In this study, the microcapsules modified with CS-g-MPEG2K-DS7% had the lowest IgG adsorption of 3.0 ± 0.6 μg/cm(2), a reduction of 61% compared to that on the chitosan surface.

  7. Surface-modified zeolite-filled chitosan membranes for pervaporation dehydration of ethanol

    NASA Astrophysics Data System (ADS)

    Sun, Honglei; Lu, Lianyu; Chen, Xue; Jiang, Zhongyi

    2008-06-01

    Surface-modified zeolite-filled chitosan (CS) membranes were prepared by incorporating 3-mercaptopropyltrimethoxysilane (MPTMS)-modified H-ZSM-5 zeolite into chitosan for pervaporation dehydration of aqueous ethanol solution. The physicochemical characterization by XPS, FT-IR, XRD, DMA and SEM showed that -SO 3H group was readily grafted on the surface of H-ZSM-5 with the mediation of MPTMS and hydrogen peroxide, and the accompanying ion-ion interaction between -SO 3H group on surface-modified H-ZSM-5 and -NH 3+ group on chitosan substantially eliminated the nonselective voids at the chitosan-H-ZSM-5 interface of the filled membranes. The experimental results also revealed that H-ZSM-5 exhibited desirable size-selective and preferential adsorption effects for aqueous ethanol solution. As a result, modified H-ZSM-5 filled membranes showed higher swelling degree and permeation flux, and improved selectivity for aqueous ethanol solution. In comparison between chitosan control membrane (permeation flux 54.18 g/(m 2 h) and separation factor 158.02 for 90 wt.% aqueous ethanol solution at 80 °C), the modified H-ZSM-5 filled membrane with 8 wt.% filling content exhibited a remarkably improved pervaporation performance with permeation flux 278.54 g/(m 2 h) and separation factor 274.46 under the identical experimental condition.

  8. Peripheral Nerve Regeneration Through Hydrogel-Enriched Chitosan Conduits Containing Engineered Schwann Cells for Drug Delivery.

    PubMed

    Meyer, Cora; Wrobel, Sandra; Raimondo, Stefania; Rochkind, Shimon; Heimann, Claudia; Shahar, Abraham; Ziv-Polat, Ofra; Geuna, Stefano; Grothe, Claudia; Haastert-Talini, Kirsten

    2016-01-01

    Critical length nerve defects in the rat sciatic nerve model were reconstructed with chitosan nerve guides filled with Schwann cells (SCs) containing hydrogel. The transplanted SCs were naive or had been genetically modified to overexpress neurotrophic factors, thus providing a cellular neurotrophic factor delivery system. Prior to the assessment in vivo, in vitro studies evaluating the properties of engineered SCs overexpressing glial cell line-derived neurotrophic factor (GDNF) or fibroblast growth factor 2 (FGF-2(18kDa)) demonstrated their neurite outgrowth inductive bioactivity for sympathetic PC-12 cells as well as for dissociated dorsal root ganglion cell drop cultures. SCs within NVR-hydrogel, which is mainly composed of hyaluronic acid and laminin, were delivered into the lumen of chitosan hollow conduits with a 5% degree of acetylation. The viability and neurotrophic factor production by engineered SCs within NVR-Gel inside the chitosan nerve guides was further demonstrated in vitro. In vivo we studied the outcome of peripheral nerve regeneration after reconstruction of 15-mm nerve gaps with either chitosan/NVR-Gel/SCs composite nerve guides or autologous nerve grafts (ANGs). While ANGs did guarantee for functional sensory and motor regeneration in 100% of the animals, delivery of NVR-Gel into the chitosan nerve guides obviously impaired sufficient axonal outgrowth. This obstacle was overcome to a remarkable extent when the NVR-Gel was enriched with FGF-2(18kDa) overexpressing SCs.

  9. Electrospun nanofibers of poly(ε-caprolactone)/depolymerized chitosan for respiratory tissue engineering applications.

    PubMed

    Mahoney, Christopher; Conklin, Dawn; Waterman, Jenora; Sankar, Jagannathan; Bhattarai, Narayan

    2016-01-01

    Synthetic grafts comprised of a porous scaffold in the size and shape of the natural tracheobronchial tree, and autologous stem cells have shown promise in the ability to restore the structure and function of a severely damaged airway system. For this specific application, the selected scaffold material should be biocompatible, elicit limited cytotoxicity, and exhibit sufficient mechanical properties. In this research, we developed composite nanofibers of polycaprolactone (PCL) and depolymerized chitosan using the electrospinning technique and assessed the properties of the fibers for its potential use as a scaffold for regenerating tracheal tissue. Water-soluble depolymerized chitosan solution was first prepared and mixed with polycaprolactone solution making it suitable for electrospinning. Morphology and chemical structure analysis were performed to confirm the structure and composition of the fibers. Mechanical testing of nanofibers demonstrated both elastic and ductile properties depending on the ratio of PCL to chitosan. To assess biological potential, porcine tracheobronchial epithelial (PTBE) cells were seeded on the nanofibers with composition ratios of PCL/chitosan: 100/0, 90/10, 80/20, and 70/30. Transwell inserts were modified with the nanofiber membrane and cells were seeded according to air-liquid interface culture techniques that mimics the conditions found in the human airways. Lactase dehydrogenase assay was carried out at different time points to determine cytotoxicity levels within PTBE cell cultures on nanofibers. This study shows that PCL/chitosan nanofiber has sufficient structural integrity and serves as a potential candidate for tracheobronchial tissue engineering.

  10. New Functionalities of PA6,6 Fabric Modified by Atmospheric Pressure Plasma and Grafted Glycidyl Methacrylate Derivatives

    USDA-ARS?s Scientific Manuscript database

    Oxidative atmospheric pressure plasma was utilized to activate surface of PA 6,6 fabrics followed by graft copolymerization of glycidyl methacrylate (GMA) and further reacted with triethylene tetramine (TETA), quaternary ammonium chitosan (HTCC) or cyclodextrin (CD). The inner CD cavity was complexe...

  11. The coagulation characteristics of humic acid by using acid-soluble chitosan, water-soluble chitosan, and chitosan coagulant mixtures.

    PubMed

    Chen, Chih-Yu; Wu, Chung-Yu; Chung, Ying-Chien

    2015-01-01

    Chitosan is a potential substitute for traditional aluminium salts in water treatment systems. This study compared the characteristics of humic acid (HA) removal by using acid-soluble chitosan, water-soluble chitosan, and coagulant mixtures of chitosan with aluminium sulphate (alum) or polyaluminium chloride (PACl). In addition, we evaluated their respective coagulation efficiencies at various coagulant concentrations, pH values, turbidities, and hardness levels. Furthermore, we determined the size and settling velocity of flocs formed by these coagulants to identify the major factors affecting HA coagulation. The coagulation efficiency of acid- and water-soluble chitosan for 15 mg/l of HA was 74.4% and 87.5%, respectively. The optimal coagulation range of water-soluble chitosan (9-20 mg/l) was broader than that of acid-soluble chitosan (4-8 mg/l). Notably, acid-soluble chitosan/PACl and water-soluble chitosan/alum coagulant mixtures exhibited a higher coagulation efficiency for HA than for PACl or alum alone. Furthermore, these coagulant mixtures yielded an acceptable floc settling velocity and savings in both installation and operational expenses. Based on these results, we confidently assert that coagulant mixtures with a 1:1 mass ratio of acid-soluble chitosan/PACl and water-soluble chitosan/alum provide a substantially more cost-effective alternative to using chitosan alone for removing HA from water.

  12. Comperative study of catalase immobilization on chitosan, magnetic chitosan and chitosan-clay composite beads.

    PubMed

    Başak, Esra; Aydemir, Tülin; Dinçer, Ayşe; Becerik, Seda Çınar

    2013-12-01

    Catalase was immobilized on chitosan and modified chitosan. Studies were carried out on free-immobilized catalase concerning the determination of optimum temperature, pH, thermal, storage stability, reusability, and kinetic parameters. Optimum temperature and pH for free catalase and catalase immobilized were found as 35°C and 7.0, respectively. After 100 times of repeated tests, the immobilized catalases on chitosan-clay and magnetic chitosan maintain over 50% and 60% of the original activity, respectively. The ease of catalase immobilization on low-cost matrices and good stability upon immobilization in the present study make it a suitable product for further use in the food industry.

  13. Antibiotic-releasing porous polymethylmethacrylate constructs for osseous space maintenance and infection control.

    PubMed

    Shi, Meng; Kretlow, James D; Nguyen, Anson; Young, Simon; Scott Baggett, L; Wong, Mark E; Kasper, F Kurtis; Mikos, Antonios G

    2010-05-01

    The use of a strategy involving space maintenance as the initial step of a two-stage regenerative medicine approach toward reconstructing significant bony or composite tissue defects in the craniofacial area, preserves the void volume of bony defects and could promote soft tissue healing prior to the subsequent definitive repair. One of the complications with a biomaterial-based space maintenance approach is local infection, which requires early, effective eradication, ideally through local antibiotic delivery. The purpose of this study is to develop a dual function implant material for maintaining osseous space and releasing an antibiotic to eliminate local infection in bony defects. Colistin, a polymyxin antibiotic, was chosen specifically to address infections with Acinetobacter species, the most common pathogen associated with combat-related traumatic craniofacial injuries. Porous polymethylmethacrylate (PMMA) constructs incorporating poly(lactic-co-glycolic acid) (PLGA) microspheres were fabricated by mixing a clinically used bone cement formulation of PMMA powder and methylmethacrylate liquid with a carboxymethylcellulose (CMC) hydrogel (40 or 50 wt%) to impart porosity and PLGA microspheres (10 or 15 wt%) loaded with colistin to control drug release. The PMMA/CMC/PLGA construct featured mild setting temperature, controllable surface/bulk porosity by incorporation of the CMC hydrogel, reasonably strong compressive properties, and continuous drug release over a period of 5 weeks with total drug release of 68.1-88.3%, depending on the weight percentage of CMC and PLGA incorporation. The concentration of released colistin was well above its reported minimum inhibitory concentration against susceptible species for 5 weeks. This study provides information on the composition parameters that enable viable porosity characteristics/drug release kinetics of the PMMA/CMC/PLGA construct for the initial space maintenance as part of a two-stage regenerative medicine

  14. Filler-coupling agent-matrix interactions in silica/polymethylmethacrylate composites.

    PubMed

    Liu, Q; Ding, J; Chambers, D E; Debnath, S; Wunder, S L; Baran, G R

    2001-12-05

    The interactions of the silane coupling agent methacryloxypropyltrimethoxysilane (MPS) with both fumed silica and a polymethylmethacrylate (PMMA) resin matrix were investigated using thermogravimetric analysis and Fourier transform infrared spectroscopy. OX 50 fumed silica was silanated with MPS at concentrations of 1% and 5% in aqueous ethanol (95%), acetone, and anhydrous toluene. Methyl methacrylate was polymerized with the silanated fumed silica (5% wt/wt) to form composites. The amount of MPS adsorption on the fumed silica and the amount of PMMA attached to the silanated fumed silica were determined by thermogravimetric analysis. MPS could be removed from the fumed silica after washing with methanol, but not after it underwent a drying process at 25 degrees C under vacuum. After vacuum drying at 25 degrees C, two types of adsorbed silane were found, i.e., firmly adsorbed and loosely adsorbed silane. The loosely adsorbed silane could desorb from silica and be incorporated into the polymer matrix through copolymerization with monomeric methyl methacrylate, resulting in crosslinking of the matrix. When the silanated silica was dried at 110 degrees C for 2 h, the loosely adsorbed silane was removed and the amount of firmly adsorbed silane increased. There was a positive correlation between the amount of firmly adsorbed MPS and the amount of PMMA attachment. The highest efficiency for PMMA attachment was found when MPS was adsorbed as a monolayer, because the loosely adsorbed silane did not contribute to the bonding of PMMA, and this suggested that not all of the double bonds of the MPS were accessible for reaction with the methacrylate monomer. Drying at 110 degrees C may also decrease the number of unsaturated double bonds of MPS.

  15. Polymethylmethacrylate and radioisotopes in vertebral augmentation: an explanation of underlying principles.

    PubMed

    Hirsch, Ariel E; Rosenstein, Barry S; Medich, David C; Martel, Christopher B; Hirsch, Joshua A

    2009-01-01

    We recently reported a novel concept for combining radioactive isotope technology with polymethylmethacrylate (PMMA) cement used for vertebral augmentation and have advocated that pain physicians become aware of this new concept when treating malignant compression fractures. The use of vertebral augmentation for malignant compression fractures is steadily increasing, and the goal of this novel approach would be to stabilize the fractured vertebral body while also controlling proliferation of the tumor cells in the vertebral body that caused the vertebral fracture. This approach would therefore provide mechanical stabilization of the fractured vertebral body at the same time as direct targeting of the cancer cells causing the fracture. For our analysis, we investigated six specific radioisotopes with regard to physical and biologic properties as they would interact with PMMA and local bone metastatic disease, taking into consideration anatomical, biological and physical characteristics. The radioisotopes investigated include beta emitting (plus and minus) sources, as well as low energy and mid-energy photon sources and are: P-32, Ho-166, Y-90, I-125, F-18, and Tc-99m. We review the advantages and disadvantages of each radioisotope. In addition, this paper serves to provide pain physicians with a basic background of the biologic principles (Biologically Effective Dose) and statistical modeling (Monte Carlo method) used in that analysis. We also review the potential complications when using radioactive sources in a clinical setting. Understanding the methodologies employed in determining isotope selection empowers the practitioner by fostering understanding of this presently theoretical treatment option. We believe that embedding radioisotopes in PMMA is merely a first step in the road of local treatment for symptomatic local lesions in the setting of systemic disease.

  16. Energy deposition around swift proton tracks in polymethylmethacrylate: How much and how far

    NASA Astrophysics Data System (ADS)

    Dapor, Maurizio; Abril, Isabel; de Vera, Pablo; Garcia-Molina, Rafael

    2017-08-01

    The use of proton beams in several modern technologies to probe or modify the properties of materials, such as proton beam lithography or ion beam cancer therapy, requires us to accurately know the extent to which the energy lost by the swift projectiles in the medium is redistributed radially around their tracks, since this determines several endpoints, such as the resolution of imaging or manufacturing techniques, or even the biological outcomes of radiotherapy. In this paper, the radial distribution of the energy deposited around swift-proton tracks in polymethylmethacrylate (PMMA) by the transport of secondary electrons is obtained by means of a detailed Monte Carlo simulation. The initial energy and angular distributions of the secondary electrons generated by proton impact, as well as the electronic cross sections for the ejection of these electrons, are reliably calculated in the framework of the dielectric formalism, where a realistic electronic excitation spectrum of PMMA is accounted for. The cascade of all secondary electrons generated in PMMA is simulated taking into account the main interactions that occur between these electrons and the condensed phase target. After analyzing the influence that several angular distributions of the electrons generated by the proton beam have on the resulting radial profiles of deposited energy, we conclude that the widely used Rudd and Kim formula should be replaced by the simpler isotropic angular distribution, which leads to radial energy distributions comparable to the ones obtained from more realistic angular distributions. By studying the dependence of the radial dose on the proton energy we recommend lower proton energies than previously published for reducing proximity effects around a proton track. The obtained results are of relevance for assessing the resolution limits of proton beam based imaging and manufacturing techniques.

  17. Evaluation of Soft Tissue Coverage over Porous Polymethylmethacrylate Space Maintainers Within Nonhealing Alveolar Bone Defects

    PubMed Central

    Kretlow, James D.; Shi, Meng; Young, Simon; Spicer, Patrick P.; Demian, Nagi; Jansen, John A.; Wong, Mark E.; Kasper, F. Kurtis

    2010-01-01

    Current treatment of traumatic craniofacial injuries often involves early free tissue transfer, even if the recipient site is contaminated or lacks soft tissue coverage. There are no current tissue engineering strategies to definitively regenerate tissues in such an environment at an early time point. For a tissue engineering approach to be employed in the treatment of such injuries, a two-stage approach could potentially be used. The present study describes methods for fabrication, characterization, and processing of porous polymethylmethacrylate (PMMA) space maintainers for temporary retention of space in bony craniofacial defects. Carboxymethylcellulose hydrogels were used as a porogen. Implants with controlled porosity and pore interconnectivity were fabricated by varying the ratio of hydrogel:polymer and the amount of carboxymethylcellulose within the hydrogel. The in vivo tissue response to the implants was observed by implanting solid, low-porosity, and high-porosity implants (n = 6) within a nonhealing rabbit mandibular defect that included an oral mucosal defect to allow open communication between the oral cavity and the mandibular defect. Oral mucosal wound healing was observed after 12 weeks and was complete in 3/6 defects filled with solid PMMA implants and 5/6 defects filled with either a low- or high-porosity PMMA implant. The tissue response around and within the pores of the two formulations of porous implants tested in vivo was characterized, with the low-porosity implants surrounded by a minimal but well-formed fibrous capsule in contrast to the high-porosity implants, which were surrounded and invaded by almost exclusively inflammatory tissue. On the basis of these results, PMMA implants with limited porosity hold promise for temporary implantation and space maintenance within clean/contaminated bone defects. PMID:20524844

  18. Octenidine in combination with polymethylmethacrylate: a new option for preventing infection?

    PubMed

    Weckbach, Sebastian; Möricke, Angelika; Braunwarth, Horst; Goroncy-Bermes, Peter; Bischoff, Mark; Gebhard, Florian

    2012-01-01

    Orthopedic implant infections represent a serious complication for both patient and surgeon. In order to minimize this risk, it has become standard practice in surgery and orthopedics to add antimicrobial substances to the polymethylmethacrylate (PMMA) bone cement. The aim of this study is to find new options for preventing infection by using alternative adjuvants in combination with PMMA. We hypothesized, that Octenidine, after being combined with PMMA, can be released in vitro and an antimicrobial efficacy of discharged Octenidine can be shown. The release of Octenidine from PMMA was assessed in high pressure liquid chromatography of the supernatant. In order to assess the efficacy of Octenidine on Staphylococcus aureus and Pseudomonas aeruginosa in vitro, a nutrient solution for these bacteria was incubated with a defined number of these bacteria (10(6) colony forming units) and cement pellets containing the antiseptic Octenidine for 24 h. After the incubation the number of bacteria in the solution was determined by counting the colony forming units on blood agar plates. Octenidine was shown to be released in a concentration-dependent manner from PMMA in the elution experiment. The experimental procedure using S. aureus demonstrated a bactericidal effect for bone cement containing Octenidine. For P. aeruginosa, bone cement containing 5-8% Octenidine was associated with tenfold reduction in bacterial count. These results suggest that Octenidine is released after combining it with PMMA and reaches working concentrations in vitro. These findings suggest a new and effective alternative for prevention of infection in cemented implants. Further investigations on the biocompatibility of this combination is needed.

  19. Visualization of Tear Clearance Using Anterior Segment Optical Coherence Tomography and Polymethylmethacrylate Particles.

    PubMed

    Zheng, Xiaodong; Yamaguchi, Masahiko; Kamao, Tomoyuki; Sakane, Yuri; Goto, Tomoko; Shiraishi, Atsushi; Ohashi, Yuichi

    2016-11-01

    We previously reported 2 new methods, anterior segment optical coherence tomography (AS-OCT) and polymethylmethacrylate particles suspended in fluorescein solution (PPF), for the evaluation of tear clearance and rapid tear flow after blinking (tear Krehbiel flow). Here, we investigated age-related OCT tear clearance and tear film thickness (TFT) and the potential correlation of OCT tear clearance and PPF velocity indicative of tear Krehbiel flow. Normal subjects separated into young and older groups received 5 μL of saline solution into the lower conjunctival sac, and an image of the central lower eyelid tear meniscus was captured by AS-OCT immediately and 30 seconds after natural blinking. Tear meniscus height (TMH) and tear meniscus area (TMA) were measured, and their percentage decrease was defined as OCT clearance rate. A Spectralis OCT Anterior Segment Module captured the central corneal tear film layer for TFT measurements. OCT clearance rates were significantly higher in young versus older subjects (P = 0.0002). When all subjects were analyzed, age was significantly and negatively correlated with TMH clearance rate (r = -0.4928, P = 0.0003) and TMA clearance rate (r = -0.4596, P = 0.0008). TFT values were significantly and negatively correlated with age (r = -0.6662, P < 0.0001). A second experiment examined tear Krehbiel flow by measuring PPF velocity in frontal and medial gaze positions. The medial gaze position showed significantly increased PPF velocity compared with the frontal gaze position (P = 0.006). Significant and positive correlations were found between OCT clearance rates and PPF velocity (TMH rate: r = 0.2926, P = 0.0392; TMA rate: r = 0.3274, P = 0.0205). AS-OCT and PPF might be novel techniques for quantitative evaluation of tear clearance and Krehbiel flow.

  20. Evaluation of soft tissue coverage over porous polymethylmethacrylate space maintainers within nonhealing alveolar bone defects.

    PubMed

    Kretlow, James D; Shi, Meng; Young, Simon; Spicer, Patrick P; Demian, Nagi; Jansen, John A; Wong, Mark E; Kasper, F Kurtis; Mikos, Antonios G

    2010-12-01

    Current treatment of traumatic craniofacial injuries often involves early free tissue transfer, even if the recipient site is contaminated or lacks soft tissue coverage. There are no current tissue engineering strategies to definitively regenerate tissues in such an environment at an early time point. For a tissue engineering approach to be employed in the treatment of such injuries, a two-stage approach could potentially be used. The present study describes methods for fabrication, characterization, and processing of porous polymethylmethacrylate (PMMA) space maintainers for temporary retention of space in bony craniofacial defects. Carboxymethylcellulose hydrogels were used as a porogen. Implants with controlled porosity and pore interconnectivity were fabricated by varying the ratio of hydrogel:polymer and the amount of carboxymethylcellulose within the hydrogel. The in vivo tissue response to the implants was observed by implanting solid, low-porosity, and high-porosity implants (n = 6) within a nonhealing rabbit mandibular defect that included an oral mucosal defect to allow open communication between the oral cavity and the mandibular defect. Oral mucosal wound healing was observed after 12 weeks and was complete in 3/6 defects filled with solid PMMA implants and 5/6 defects filled with either a low- or high-porosity PMMA implant. The tissue response around and within the pores of the two formulations of porous implants tested in vivo was characterized, with the low-porosity implants surrounded by a minimal but well-formed fibrous capsule in contrast to the high-porosity implants, which were surrounded and invaded by almost exclusively inflammatory tissue. On the basis of these results, PMMA implants with limited porosity hold promise for temporary implantation and space maintenance within clean/contaminated bone defects.

  1. Clinical application of a pedicle nail system with polymethylmethacrylate for osteoporotic vertebral fracture

    PubMed Central

    Tanaka, Masato; Sugimoto, Yoshihisa; Takigawa, Tomoyuki; Ozaki, Toshifumi; Konishi, Hitoshi

    2010-01-01

    The instrumentation of the osteoporotic spine may sometimes result in failure due to the loosening or pullout of the conventional pedicle screw. Moreover, augmentation of screws with polymethylmethacrylate (PMMA) has risks of complications. We developed a new and original pedicle nail system with PMMA for osteoporotic vertebral fractures. A clinical evaluation of this novel pedicle nail system utilized in patients with an osteoporotic vertebral collapse was performed to determine the effectiveness and safety of this technique. Thirty-four elderly patients who suffered from osteoporotic compression fractures were treated by posterolateral fusion using the pedicle nail system. The mean follow-up period was 37 months. Of the 25 patients with neurological symptoms, two patients improved two stages at the Frankel level. Fifteen patients improved one stage at the Frankel level, and eight other patients improved, however, their improvement did not exceed a Frankel level. Nine cases with neuralgia symptoms improved from 4.4 to 2.2 points on average on the Denis pain scale (p < 0.01). The fusion rate was 94% as determined by X-rays of flexion and extension, and the correction of the compression fracture site was maintained well. A pedicle nail system stabilizes the spinal column with osteoporosis and reduces the instrumentation failure. The technique for the insertion of the pedicle nail reduces complication from cement augmentation. The authors speculate that the strategy using the pedicle nail system for osteoporotic spine may be effective and safe when the surgery is performed through a posterior approach. PMID:20414689

  2. Flame spread over thick polymethylmethacrylate samples in a simulated and actual microgravity environment

    NASA Astrophysics Data System (ADS)

    Shah, Tirthesh Jayesh

    The NASA Burning and Suppression of Solids-II (BASS II) experiment examines the combustion of different solid materials and material geometries in microgravity. While flames in microgravity are driven by diffusion and weak advection due to crew movements and ventilation, the current NASA spacecraft material selection test method (NASA-STD- 6001 Test 1) is driven by buoyant forces as gravity is present. The overall goal of this project is to understand the burning of intermediate and thick fuels in microgravity, and devise a normal gravity test to apply to future materials. Clear cast polymethylmethacrylate (PMMA) samples 10 cm long by 1 or 2 cm wide with thicknesses ranging from 1-5 mm were investigated. PMMA is the ideal choice since it is widely used and we know its stoichiometric chemistry. Tests included both one sided and two sided burns. Samples are ignited by heating a wire behind the sample. The samples are burned in a flow duct within the Microgravity Science Glovebox (MSG) on the International Space Station (ISS) to ensure true microgravity conditions. The experiment takes place in opposed flow with varying Oxygen concentrations and flow velocities. Flames are recorded on two cameras and later tracked to determine spread rate. Currently we are modeling combustion of PMMA using Fire Dynamics Simulator (FDS 5.5.3) and Smokeview. The entire modelling for BASS-II is done in DNS mode because of the laminar conditions and small domain. In DNS mode the Navier Stokes equations are solved without the Turbulence model. The model employs the same test sample and MSG geometry as the experiment; but in 2D. The experimental data gave upstream velocity at several points using an anemometer. A flow profile for the inlet velocity is obtained using Matlab and input into the model. The flame spread rates obtained after tracking are then compared with the experimental data and the results follow the trends but the spread rates are higher.

  3. Antibiotic-releasing Porous Polymethylmethacrylate Constructs for Osseous Space Maintenance and Infection Control

    PubMed Central

    Shi, Meng; Kretlow, James D.; Nguyen, Anson; Young, Simon; Baggett, L. Scott; Wong, Mark E.; Kasper, F. Kurtis; Mikos, Antonios G.

    2010-01-01

    The use of a strategy involving space maintenance as the initial step of a two-stage regenerative medicine approach toward reconstructing significant bony or composite tissue defects in the craniofacial area, preserves the void volume of bony defects and could promote soft tissue healing prior to the subsequent definitive repair. One of the complications with a biomaterial-based space maintenance approach is local infection, which requires early, effective eradication, ideally through local antibiotic delivery. The purpose of this study is to develop a dual function implant material for maintaining osseous space and releasing an antibiotic to eliminate local infection in bony defects. Colistin, a polymyxin antibiotic, was chosen specifically to address infections with Acinetobacter species, the most common pathogen associated with combat-related traumatic craniofacial injuries. Porous polymethylmethacrylate (PMMA) constructs incorporating poly(lactic-co-glycolic acid) (PLGA) microspheres were fabricated by mixing a clinically used bone cement formulation of PMMA powder and methylmethacrylate liquid with a carboxymethylcellulose (CMC) hydrogel (40 or 50 wt%) to impart porosity and PLGA microspheres (10 or 15 wt%) loaded with colistin to control drug release. The PMMA/CMC/PLGA construct featured mild setting temperature, controllable surface/bulk porosity by incorporation of the CMC hydrogel, reasonably strong compressive properties, and continuous drug release over a period of 5 weeks with total drug release of 68.1-88.3%, depending on the weight percentage of CMC and PLGA incorporation. The concentration of released colistin was well above its reported minimum inhibitory concentration against susceptible species for 5 weeks. This study provides information on the composition parameters that enable viable porosity characteristics/drug release kinetics of the PMMA/CMC/PLGA construct for the initial space maintenance as part of a two-stage regenerative medicine

  4. Adsorptive removal of copper (II) and lead (II) using chitosan-g-maleic anhydride-g-methacrylic acid copolymer.

    PubMed

    Lavanya, R; Gomathi, T; Vijayalakshmi, K; Saranya, M; Sudha, P N; Anil, Sukumaran

    2017-11-01

    In the present work, the maleic anhydride and methacrylic acid monomers were grafted one after another onto chitosan by using ceric ammonium nitrate as the initiator. The optimum conditions for grafting were studied by varying the initiator concentration, monomer concentration and reaction temperature. The synthesized grafted samples were subjected to various analytical techniques such as FTIR, XRD, TGA and DSC methods The proof of formation of graft copolymer was ascertained from the results of FTIR analysis and XRD studies. The TGA and DSC results conclude the highly thermally stable behavior of the prepared graft copolymer sample. The prepared graft copolymer was utilized for removing copper and lead from aqueous solutions and optimum adsorption parameters were evaluated under various pH, adsorbent dose, contact time and initial metal ion concentration. The adsorption and kinetic studies have been explained by Langmuir, Freundlich and pseudo - first order, second order and intra particle diffusion models. From the results, it was seen that Freundlich isotherm was best fit in the case of adsorption studies which followed pseudo second order kinetics. The obtained results showed that the chitosan-g-maleic anhydride-g-methacrylic acid copolymer was very efficient in removing the heavy metals copper and lead from aqueous solution. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. [Polymethylmethacrylate augmentation of bone cement-injectable cannulated pedicle screws for the treatment of degenerative lumbar diseases with osteoporosis].

    PubMed

    Sun, H L; Li, C D; Yang, Z C; Yi, X D; Liu, H; Lu, H L; Li, H; Wang, Y

    2016-12-18

    To describe the application of polymethylmethacrylate augmentation of bone cement-injectable cannulated pedicle screws for the treatment of degenerative lumbar diseases with osteoporosis. Observation group included 14 cases of degenerative lumbar diseases with osteoporosis received polymethylmethacrylate augmentation of bone cement-injectable cannulated pedicle screws from November 2014 to July 2015, control group included 12 cases of degenerative lumbar diseases with osteoporosis received polymethylmethacrylate augmentation with traditional pedicle screws.The operation time, blood loss, number of pedicle screws and number of augmented pedicle screws in the two groups were compared. The bone cement leakage and pulmonary bone cement embolism in the two groups were also compared. The fusion rate and pedicle screws loosening by lumbar X ray and dynamic X ray were evaluated. The clinical results were assessed by visual analog scale (VAS) of pain on lumbar and lower limbers, lumbar Japanese Orthopaedic Association scores (JOA), Prolo functional scores and Oswestry disability (ODI) scores. Differences of operation time and blood loss in the two groups were not statistically significant. The average number of pedicle screws was 9.9±4.7 and the average number of augmented pedicle screws was 5.9±2.6 in observation group while the average number of pedicle screws was 7.1±2.8 and the average number of augmented pedicle screws was 3.0±1.9 in control group. The ratio of augmented pedicle screws was higher in observation group than in control group (0.69±0.30 vs.0.47±0.30,P<0.05). The bone cement leakage rate was lower in observation group than in control group (5/83 vs. 12/42, P<0.01). All the cases in observation group were without leakage to the interspinal canal while one case in control group suffered from bone cement leakage to the interspinal canal with augmentation of 3 pedicle screws. The follow up period was (10.6±2.3) months in observation group and (36.5±7

  6. A high-quality narrow passband filter for elastic SV waves via aligned parallel separated thin polymethylmethacrylate plates

    NASA Astrophysics Data System (ADS)

    Zhang, Jun; Liu, Yaolu; Yan, Wensheng; Hu, Ning

    2017-08-01

    We designed a high-quality filter that consists of aligned parallel polymethylmethacrylate (PMMA) thin plates with small gaps for elastic SV waves propagate in metals. Both the theoretical model and the full numerical simulation show the transmission spectrum of the elastic SV waves through such a filter has several sharp peaks with flawless transmission within the investigated frequencies. These peaks can be readily tuned by manipulating the geometry parameters of the PMMA plates. Our investigation finds that the same filter performs well for different metals where the elastic SV waves propagated.

  7. Chitosan-plasmid DNA nanoparticles encoding small hairpin RNA targeting MMP-3 and -13 to inhibit the expression of dedifferentiation related genes in expanded chondrocytes.

    PubMed

    Zhao, Jingxin; Fan, Xiangli; Zhang, Qiang; Sun, Fangfei; Li, Xiaojian; Xiong, Chuan; Zhang, Chunli; Fan, Hongbin

    2014-02-01

    Overexpression of matrix metalloproteinase (MMP)-3 and -13 can lead to the dedifferentiation of expanded chondrocytes. After implanting dedifferentiated cells for cartilage defect repair, graft failure may occur. Short hairpin RNA (shRNA) is a powerful genetic tool to reduce the expression of target genes. This study investigated the effects of chitosan-plasmid DNA (pDNA) nanoparticles encoding shRNA targeting MMP-3 and -13 on the dedifferentiation of expanded chondrocytes. The objective was to optimize the parameters of chitosan-pDNA formulation for achieving higher efficiency of pDNA delivery and gene silencing. The chitosan-pDNA nanoparticles were prepared using a complex coacervation process. Then the characteristics including size, shape, stability, and transfection efficiency were compared in different groups. The results indicated that chitosan of 800 kDa at N/P ratio of 4 and pH 7.0 was optimal to prepare chitosan-pDNA nanoparticles. These nanoparticles showed high DNA loading efficiency (95.8 ± 1.5%) and high gene transfection efficiency (24.5 ± 1.6%). After the expanded chondrocytes were transfected by chitosan-pDNA nanoparticles, MMP-3-610 and MMP-13-2024 groups showed greater suppression in mRNA and protein levels. The results indicated that chitosan-pDNA nanoparticles encoding shRNA targeting MMP-3 and -13 had great potential in silencing the dedifferentiation-related genes for regenerating prolonged and endurable cartilage.

  8. [Naringin reduced polymethylmethacrylate-induced osteolysis in the mouse air sacs model].

    PubMed

    Li, Nian-Hu; Xu, Zhan-wang

    2015-04-01

    To evaluate the influence of naringin on PMMA-induced osteoclastic bone resorption using the mouse air sacs model. Total 48 female Balb/c mices with the age of 8 to 10 weeks were chosen in the study. Air were injected into the back in 32 mices and formed the air sacs, 6 d later, the skulls (originated from other 16 mices) were implanted to the air sacs. Thirty-two animals were divided into naringin treatment group (with 2 concentrations of 150 mg/kg and 30 mg/ kg) , DMSO group and PBS blank group, 8 animals in each group. Polymethylmethacrylate (PMMA) particles were injected into the air sacs in naringin treatment groups and DMSO group so as to irritate inflammatory reaction. Naringin with 2 concentrations of 150 mg/kg and 30 mg/kg were dissolved in DMSO of 0.2 ml, and were injected into air sacs, respectively. In PBS black group, no stimulation with PMMA particles, only injected PBS, and in DMSO group, injected DMSO without naringin. Tartrate resistant acid phosphatase (TRAP), Ca2+ release, modified Masson stain and histological analysis were performed on the 7th day after stimulation. Compared with DMSO group, naringin treatment group's cellular infiltration decreased (P < 0.01); concentration of 150 mg/kg was better than that of concentrations of 30 mg/kg (8.90 ± 1.75 vs 15.23 ± 1.86). Naringin can decrease calcium release in the lavage of the air sacs bone resorption model, especially obvious in naringin with concentration of 150 mg/kg. Naringin can ameliorate the inflammatory reaction and the subsequent bone resorption (including bone collagen loss, TRAP positive cells amount and so on) in air sacs with bone implant and PMMA particles. Naringin with concentration of 150 mg/kg appeared to be an optimal dosage to deliver the therapeutic effects. Naringin inhibits PMMA-induced osteoclastogenesis and ameliorates the PMMA-associated inflammatory reaction and the subsequent bone resorption.

  9. Interbody distraction and vertebral body reconstruction with polymethylmethacrylate for the treatment of pathological fractures.

    PubMed

    Zuckerman, Scott L; Rao, Ganesh; Rhines, Laurence D; McCutcheon, Ian E; Everson, Richard G; Tatsui, Claudio E

    2017-10-06

    OBJECTIVE Treatment of epidural spinal cord compression (ESCC) caused by tumor includes surgical decompression and stabilization followed by postoperative radiation. In the case of severe axial loading impairment, anterior column reconstruction is indicated. The authors describe the use of interbody distraction to restore vertebral body height and correct kyphotic angulation prior to reconstruction with polymethylmethacrylate (PMMA), and report the long-term durability of such reconstruction. METHODS A single institution, prospective series of patients with ESCC undergoing single-stage decompression, anterior column reconstruction, and posterior instrumentation from 2013 to 2016 was retrospectively analyzed. Several demographic, perioperative, and radiographic measurements were collected. Descriptive statistics were compiled, in addition to postoperative changes in anterior height, posterior height, and kyphosis. Paired Student t-tests were performed for each variable. Overall survival was calculated using the techniques described by Kaplan and Meier. RESULTS Twenty-one patients underwent single-stage posterior decompression with interbody distraction and anterior column reconstruction using PMMA. The median age and Karnofsky Performance Scale score were 61 years and 70, respectively. Primary tumors included renal cell (n = 8), lung (n = 4), multiple myeloma (n = 2), prostate (n = 2), and other (n = 5). Eighteen patients underwent a single-level vertebral body reconstruction and 3 underwent multilevel transpedicular corpectomies. The median survival duration was 13.3 months. In the immediate postoperative setting, statistically significant improvement was noted in anterior body height (p = 0.0017, 95% confidence interval [CI] -4.15 to -1.11) and posterior body height (p = 0.0116, 95% CI -3.14 to -0.45) in all patients, and improved kyphosis was observed in those with oblique endplates (p = 0.0002, 95% CI 11.16-20.27). In the median follow-up duration of 13.9 months

  10. Antifungal, optical, and mechanical properties of polymethylmethacrylate material incorporated with silanized zinc oxide nanoparticles

    PubMed Central

    Kamonkhantikul, Krid; Arksornnukit, Mansuang; Takahashi, Hidekazu

    2017-01-01

    Background Fungal infected denture, which is typically composed of polymethylmethacrylate (PMMA), is a common problem for a denture wearer, especially an elderly patient with limited manual dexterity. Therefore, increasing the antifungal effect of denture by incorporating surface modification nanoparticles into the PMMA, while retaining its mechanical properties, is of interest. Aim of the study This study aimed to evaluate antifungal, optical, and mechanical properties of heat-cured PMMA incorporated with different amounts of zinc oxide nanoparticles (ZnOnps) with or without methacryloxypropyltrimethoxysilane modification. Materials and methods Specimens made from heat-cured PMMA containing 1.25, 2.5, and 5% (w/w) nonsilanized (Nosi) or silanized (Si) ZnOnps were evaluated. Specimens without filler served as control. The fungal assay was performed placing a Candida albicans suspension on the PMMA surface for 2 h, then Sabouraud Dextrose Broth was added, and growth after 24 h was determined by counting colony forming units on agar plates. A spectrophotometer was used to measure the color in L* (brightness), a* (red-green), b* (yellow-blue) and opacity of the experimental groups. Flexural strength and flexural modulus were determined using a three-point bending test on universal testing machine after 37°C water storage for 48 h and 1 month. Results The antifungal, optical, and mechanical properties of the PMMA incorporated with ZnOnps changed depending on the amount. With the same amount of ZnOnps, the silanized groups demonstrated a greater reduction in C. albicans compared with the Nosi groups. The color difference (ΔE) and opacity of the Nosi groups were greater compared with the Si groups. The flexural strength of the Si groups, except for the 1.25% group, was significantly greater compared with the Nosi groups. Conclusion PMMA incorporated with Si ZnOnps, particularly with 2.5% Si ZnOnps, had a greater antifungal effect, less color differences, and opacity

  11. Preparation of cationic chitosan-polyacrylamide flocculant and its properties in wastewater treatment

    NASA Astrophysics Data System (ADS)

    Wang, Ben; Zhang, Yulian; Miao, Chunbao

    2011-03-01

    Chitosan derived from crab shells, was used to prepare the graft polymer in aqueous solution with acrylamide (AM) and methacrylatoethyl trimethyl ammonium chloride (DMC) as raw materials and ceric ammonium nitrate (CAN) as initiator. The flocculation ability of the resulting polymer (PCAD) was studied in waste water treatment experiments. Its properties were determined on the basis of the transmittance of waste water after flocculation. The effects of chitosan and DMC content on PCAD's flocculation ability were studied. Flocculation experiments were also undertaken under various pH conditions. According to the experimental data, the flocculation ability could be improved when chitosan content decreased in the raw material, but the monomer conversion would decrease obviously. When the chitosan's content was more than 65%, AM and DMC groups were less on each chitosan molecule. So PCAD's flocculation ability was poor. Similarly, high content of DMC would result in low monomer conversion and high flocculation ability. PCAD molecules with more DMC group had more positive charges. It was favorable to flocculation. However, monomer conversion would decrease with the increase of DMC content. The suitable conditions were that chitosan and DMC contents were 65% and 15-20%, respectively. The experiment data showed that PCAD had good flocculation ability under weak acidic condition. Its ability would be weakened by strong acidic or alkaline condition. The flocculation efficiency was the best at pH of 5.5 when PCAD's dosage was 8mg·L-1. Compared with cationic polymer (the copolymer of AM and DMC, PAD), PCAD showed better flocculation ability under acid and neutral conditions, but worse ability under alkaline condition.

  12. Spinning of hydroalcoholic chitosan solutions.

    PubMed

    Desorme, Mylène; Montembault, Alexandra; Lucas, Jean-Michel; Rochas, Cyrille; Bouet, Thierry; David, Laurent

    2013-10-15

    We investigated the spinning of hydroalcoholic chitosan solutions. The dope composition was optimized in order to obtain a continuous alcogel fiber by water evaporation on heating the extruded hydroalcoholic solution. This alcogel fiber was then neutralized in aqueous alkali baths and washed in water to eliminate the residual alcohol and salts before final drying. Depending on the alcohol content in the filament at the neutralization step, on specific alcohol-chitosan interactions and on the nature and concentration of the coagulation base, the process yielded semicrystalline chitosan fibers with different proportions of anhydrous and hydrated allomorphs. Contrarily to the classical annealing method, the formation of mainly anhydrous crystals was obtained without significant molecular weight decrease by neutralizing the polymer in hydrophobic conditions. The control of allomorph content was shown to be related to the hydrophobicity of the solvent (alcohol fraction) at the neutralization step. Copyright © 2013 Elsevier Ltd. All rights reserved.

  13. Synthetic bone graft versus autograft or allograft for spinal fusion: a systematic review.

    PubMed

    Buser, Zorica; Brodke, Darrel S; Youssef, Jim A; Meisel, Hans-Joerg; Myhre, Sue Lynn; Hashimoto, Robin; Park, Jong-Beom; Tim Yoon, S; Wang, Jeffrey C

    2016-10-01

    The purpose of this review was to compare the efficacy and safety of synthetic bone graft substitutes versus autograft or allograft for the treatment of lumbar and cervical spinal degenerative diseases. Multiple major medical reference databases were searched for studies that evaluated spinal fusion using synthetic bone graft substitutes (either alone or with an autograft or allograft) compared with autograft and allograft. Randomized controlled trials (RCT) and cohort studies with more than 10 patients were included. Radiographic fusion, patient-reported outcomes, and functional outcomes were the primary outcomes of interest. The search yielded 214 citations with 27 studies that met the inclusion criteria. For the patients with lumbar spinal degenerative disease, data from 19 comparative studies were included: 3 RCTs, 12 prospective, and 4 retrospective studies. Hydroxyapatite (HA), HA+collagen, β-tricalcium phosphate (β-TCP), calcium sulfate, or polymethylmethacrylate (PMMA) were used. Overall, there were no differences between the treatment groups in terms of fusion, functional outcomes, or complications, except in 1 study that found higher rates of HA graft absorption. For the patients with cervical degenerative conditions, data from 8 comparative studies were included: 4 RCTs and 4 cohort studies (1 prospective and 3 retrospective studies). Synthetic grafts included HA, β-TCP/HA, PMMA, and biocompatible osteoconductive polymer (BOP). The PMMA and BOP grafts led to lower fusion rates, and PMMA, HA, and BOP had greater risks of graft fragmentation, settling, and instrumentation problems compared with iliac crest bone graft. The overall quality of evidence evaluating the potential use and superiority of the synthetic biological materials for lumbar and cervical fusion in this systematic review was low or insufficient, largely due to the high potential for bias and small sample sizes. Thus, definitive conclusions or recommendations regarding the use of these

  14. Meniscal allograft transplantation. Part 1: systematic review of graft biology, graft shrinkage, graft extrusion, graft sizing, and graft fixation.

    PubMed

    Samitier, Gonzalo; Alentorn-Geli, Eduard; Taylor, Dean C; Rill, Brian; Lock, Terrence; Moutzouros, Vasilius; Kolowich, Patricia

    2015-01-01

    To provide a systematic review of the literature regarding five topics in meniscal allograft transplantation: graft biology, shrinkage, extrusion, sizing, and fixation. A systematic literature search was conducted using the PubMed (MEDLINE), ScienceDirect, and EBSCO-CINAHL databases. Articles were classified only in one topic, but information contained could be reported into other topics. Information was classified according to type of study (animal, in vitro human, and in vivo human) and level of evidence (for in vivo human studies). Sixty-two studies were finally included: 30 biology, 3 graft shrinkage, 11 graft extrusion, 17 graft size, and 6 graft fixation (some studies were categorized in more than one topic). These studies corresponded to 22 animal studies, 22 in vitro human studies, and 23 in vivo human studies (7 level II, 10 level III, and 6 level IV). The principal conclusions were as follows: (a) Donor cells decrease after MAT and grafts are repopulated with host cells form synovium; (b) graft preservation alters collagen network (deep freezing) and causes cell apoptosis with loss of viable cells (cryopreservation); (c) graft shrinkage occurs mainly in lyophilized and gamma-irradiated grafts (less with cryopreservation); (d) graft extrusion is common but has no clinical/functional implications; (e) overall, MRI is not superior to plain radiograph for graft sizing; (f) graft width size matching is more important than length size matching; (g) height appears to be the most important factor influencing meniscal size; (h) bone fixation better restores contact mechanics than suture fixation, but there are no differences for pullout strength or functional results; and (i) suture fixation has more risk of graft extrusion compared to bone fixation. Systematic review of level II-IV studies, Level IV.

  15. Transformation of thiolated chitosan-templated gold nanoparticles to huge microcubes

    SciTech Connect

    Sun, Yudie; Liu, Honglin; Yang, Liangbao; Sun, Bai; Liu, Jinhuai

    2014-05-01

    Graphical abstract: - Highlights: • Mercapto groups were grafted to chitosan molecule by a reactive amine reduction. • Functional polymer with well-defined monomer units controls AuNPs assembly. • Assembled morphologies depend on the ratio of AuNPs to thiolate groups. • Microcubes with side length of ∼20 μm was synthesized through a dialysis step. • A edge-to-middle growth mechanism of gold microcubes was observed. - Abstract: The L-cysteine molecules were successfully grafted to the 2-amino group of chitosan by a reactive amine reduction, and the as-synthesized thiolated chitosan (TC) molecules were used as the templates to direct the self-assembly of gold nanoparticles and induce the transformation of these assemblies to gold microcubes through a deep-going dialysis. We found that the ratio of gold nanoparticles to TC molecules could greatly affect the shape of the assembled clusters. Different stages of these clusters and microstructures during the dialysis process were characterized by scanning electron microscope (SEM), and the microcubes with average side length of about 20 μm were successfully synthesized. According to the morphology evolution of the assembly, it could be concluded that the microcubes were formed from external to internal. The SERS area mapping images of microcubes and some clusters were also collected to study the formation mechanism of gold microcubes. Our work demonstrates a simple and highly effective way to assemble gold nanoparticles into microcubes with unique properties.

  16. Electrical regulation of Schwann cells using conductive polypyrrole/chitosan polymers.

    PubMed

    Huang, Jinghui; Hu, Xueyu; Lu, Lei; Ye, Zhengxu; Zhang, Quanyu; Luo, Zhuojing

    2010-04-01

    Electrical stimulation (ES) can dramatically enhance neurite outgrowth through conductive polymers and accelerate peripheral nerve regeneration in animal models of nerve injury. Therefore, conductive tissue engineering graft in combination with ES is a potential treatment for neural injuries. Conductive tissue engineering graft can be obtained by seeding Schwann cells on conductive scaffold. However, when ES is applied through the conductive scaffold, the impact of ES on Schwann cells has never been investigated. In this study, a biodegradable conductive composite made of conductive polypyrrole (PPy, 2.5%) and biodegradable chitosan (97.5%) was prepared in order to electrically stimulate Schwann cells. The tolerance of Schwann cells to ES was examined by a cell apoptosis assay. The growth of the cells was characterized using DAPI staining and a MTT assay. mRNA and protein levels of nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF) in Schwann cells were assayed by RT-PCR and Western blotting, and the amount of NGF and BDNF secreted was determined by an ELISA assay. The results showed that the PPy/chitosan membranes supported cell adhesion, spreading, and proliferation with or without ES. Interestingly, ES applied through the PPy/chitosan composite dramatically enhanced the expression and secretion of NGF and BDNF when compared with control cells without ES. These findings highlight for the first time the possibility of enhancing nerve regeneration in conductive scaffolds through ES-increased neurotrophin secretion.

  17. Chitosan-g-poly(N-isopropylacrylamide) copolymers as delivery carriers for intracameral pilocarpine administration.

    PubMed

    Lai, Jui-Yang; Luo, Li-Jyuan

    2017-04-01

    This study reports, for the first time, the development of a chitosan-g-poly(N-isopropylacrylamide) (Chi-PN) biodegradable in situ gelling delivery system for ocular pilocarpine administration through intracameral injection. The number of thermo-responsive polymer segments grafted onto the chitosan via carbodiimide-mediated formation of amide linkages was greatly affected by varying the feeding amount of carboxyl-terminated poly(N-isopropylacrylamide) in the synthesis, thereby determining the phase transition temperature and enzymatic degradability of Chi-PN materials. The increase in grafting ratio facilitated temperature triggered gelation and drug encapsulation at physiological conditions. Additionally, the slow biodegradation process of delivery carriers was responsible for the delayed pilocarpine release, which allowed that the drug concentration could reach minimum therapeutic level for treating glaucoma during 42days of the study. All of the synthesized Chi-PN carriers demonstrated good ocular biocompatibility with lens epithelial cell cultures. In a rabbit model of experimental glaucoma, the intraocular pressure-lowering and miotic as well as corneal endothelial preservation responses to pilocarpine strongly depended on the drug release profiles. It is concluded that injectable biodegradable chitosan-based thermogels can be potentially utilized as intracameral biomaterials for extended release of antiglaucoma medications and improved performance of delivery carriers.

  18. Novel glycol chitosan-based polymeric gene carrier synthesized by a Michael addition reaction with low molecular weight polyethylenimine.

    PubMed

    Lee, Young Hwa; Park, Hae In; Choi, Joon Sig

    2016-02-10

    A glycol chitosan-based polymer that spontaneously assembles with plasmid DNA into nanorods was evaluated as a non-viral vector for gene delivery. Glycol chitosan-methyl acrylate-polyethylenimine (GMP) was synthesized by grafting polyethylenimine onto glycol chitosan via amidation after Michael addition using methyl acrylate. Gel retardation and PicoGreen assay experiments showed complete complex formation with plasmid DNA. GMP/pDNA complexes were characterized using biophysical techniques and were found to be positively charged rod-shape structures with widths in the nanometer scale and lengths in the micrometer scale. Transfection efficiency and cytotoxicity of GMP polymer was evaluated in human epithelial ovary carcinoma (HeLa) cells, human embryonic kidney 293 (HEK293) cells, and human hepatocellular liver carcinoma (HepG2) cells, in comparison to high molecular weight polyethylenimine, a commonly used transfection reagent. Intracellular polymer uptake was compared and confirmed by confocal microscopy. The results demonstrate that GMP, a hybrid polymer of glycol chitosan grafted with branched polyethylenimine, may serve as a promising vehicle for efficient gene delivery.

  19. Antimicrobial activity of hydroxylbenzenesulfonailides derivatives of chitosan, chitosan sulfates and carboxymethyl chitosan.

    PubMed

    Zhong, Zhimei; Li, Pengcheng; Xing, Ronge; Liu, Song

    2009-08-01

    Chitosan, carboxymethyl chitosan (CMCS) and chitosan sulfates (CSS) with different molecular weight were modified by reacting with 4-hydroxyl-5-chloride-1,3-benzene-disulfo-chloride or 2-hydroxyl-5-chloride-1,3-benzene-disulfo-chloride to give 12 kinds of new hydroxylbenzenesulfonailides derivatives of them. The preparation conditions of the derivatives were discussed in this paper, and their structures were characterized by FT-IR and 13C NMR spectroscopy. The solubility of the derivatives was measured in the experiment. In addition, their antimicrobial activities against four bacteria and five crop-threatening pathogenic fungi were tested in the experiment. Besides, the rule and mechanism of their antibacterial activities were discussed in this paper.

  20. New nerve regeneration strategy combining laminin-coated chitosan conduits and stem cell therapy.

    PubMed

    Hsu, Sung-Hao; Kuo, Wen-Chun; Chen, Yu-Tzu; Yen, Chen-Tung; Chen, Ying-Fang; Chen, Ko-Shao; Huang, Wen-Cheng; Cheng, Henrich

    2013-05-01

    Nerve regeneration remains a difficult challenge due to the lack of safe and efficient matrix support. We designed a laminin (LN)-modified chitosan multi-walled nerve conduit combined with bone marrow stem cell (BMSC) grating to bridge a 10 mm long gap in the sciatic nerve of Sprague-Dawley rats. The repair outcome was monitored during 16 weeks after surgery. Successful grafting of LN onto the chitosan film, confirmed by immunolocalization, significantly improved cell adhesion. In vivo study showed that newly formed nerve cells covered the interior of the conduit to connect the nerve gap successfully in all groups. The rats implanted with the conduit combined with BMSCs showed the best results, in terms of nerve regrowth, muscle mass of gastrocnemius, function recovery and tract tracing. Neuroanatomical horseradish peroxidase tracer analysis of motor neurons in the lumbar spinal cord indicated that the amount and signal intensity were significantly improved. Furthermore, BMSCs suppressed neuronal cell death and promoted regeneration by suppressing the inflammatory and fibrotic response induced by chitosan after long-term implantation. In summary, this study suggests that LN-modified chitosan multi-walled nerve conduit combined with BMSCs is an efficient and safe conduit matrix for nerve regeneration. Copyright © 2013 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  1. Application of chitosan-based nanocarriers in tumor-targeted drug delivery.

    PubMed

    Ghaz-Jahanian, Mohammad Ali; Abbaspour-Aghdam, Farzin; Anarjan, Navideh; Berenjian, Aydin; Jafarizadeh-Malmiri, Hoda

    2015-03-01

    Cancer is one of the major malignant diseases in the world. Current anti tumor agents are restricted during the chemotherapy due to their poor solubility in aqueous media, multidrug resistance problems, cytotoxicity, and serious side effects to healthy tissues. Development of targeted drug nanocarriers would enhance the undesirable effects of anticancer drugs and also selectively deliver them to cancerous tissues. Variety of nanocarriers such as micelles, polymeric nanoparticles, liposomes nanogels, dendrimers, and carbon nanotubes have been used for targeted delivery of anticancer agents. These nanocarriers transfer loaded drugs to desired sites through passive or active efficacy mechanisms. Chitosan and its derivatives, due to their unique properties such as hydrophilicity, biocompatibility, and biodegradability, have attracted attention to be used in nanocarriers. Grafting cancer-specific ligands onto the Chitosan nanoparticles, which leads to ligand-receptor interactions, has been successfully developed as active targeting. Chitosan-conjugated components also respond to external or internal physical and chemical stimulus in targeted tumors that is called environment triggers. In this study, mechanisms of targeted tumor deliveries via nanocarriers were explained; specifically, chitosan-based nanocarriers in tumor-targeting drug delivery were also discussed.

  2. Preparation and Characterization of Films Extruded of Polyethylene/Chitosan Modified with Poly(lactic acid).

    PubMed

    Quiroz-Castillo, Jesús Manuel; Rodríguez-Félix, Dora Evelia; Grijalva-Monteverde, Heriberto; Lizárraga-Laborín, Lauren Lucero; Castillo-Ortega, María Mónica; Del Castillo-Castro, Teresa; Rodríguez-Félix, Francisco; Herrera-Franco, Pedro Jesús

    2014-12-30

    The use of mixtures of synthetic and natural polymers is a potential option to reduce the pollution by plastic waste. In this work, the method for the chemical modification of chitosan with poly(lactic acid) was developed; then, the preparation of films of blends of polyethylene and chitosan-poly(lactic acid) produced by an extrusion method using polyethylene-graft maleic anhydride as a compatibilizer. It was possible to obtain films with a maximum content of 20 wt% and 30 wt%, chitosan, with and without compatibilizer, respectively. Scanning electron microscope (SEM) analysis showed a homogeneous surface on all films. The addition of the compatibilizer had a significant effect on the mechanical properties of the films, such as an increase in Young's modulus and a decrease in the elongation at break; additionally, the compatibilizer promotes thermal degradation in a single step and gives the film a slight increase in thermal resistance. These results are attributed to an improved interaction in the interface of polyethylene and chitosan-poly(lactic acid), promoted by the compatibilizer.

  3. Preparation and Characterization of Films Extruded of Polyethylene/Chitosan Modified with Poly(lactic acid)

    PubMed Central

    Quiroz-Castillo, Jesús Manuel; Rodríguez-Félix, Dora Evelia; Grijalva-Monteverde, Heriberto; Lizárraga-Laborín, Lauren Lucero; Castillo-Ortega, María Mónica; del Castillo-Castro, Teresa; Rodríguez-Félix, Francisco; Herrera-Franco, Pedro Jesús

    2014-01-01

    The use of mixtures of synthetic and natural polymers is a potential option to reduce the pollution by plastic waste. In this work, the method for the chemical modification of chitosan with poly(lactic acid) was developed; then, the preparation of films of blends of polyethylene and chitosan-poly(lactic acid) produced by an extrusion method using polyethylene-graft maleic anhydride as a compatibilizer. It was possible to obtain films with a maximum content of 20 wt% and 30 wt%, chitosan, with and without compatibilizer, respectively. Scanning electron microscope (SEM) analysis showed a homogeneous surface on all films. The addition of the compatibilizer had a significant effect on the mechanical properties of the films, such as an increase in Young’s modulus and a decrease in the elongation at break; additionally, the compatibilizer promotes thermal degradation in a single step and gives the film a slight increase in thermal resistance. These results are attributed to an improved interaction in the interface of polyethylene and chitosan-poly(lactic acid), promoted by the compatibilizer. PMID:28787928

  4. Biophysicochemical evaluation of chitosan-hydroxyapatite-marine sponge collagen composite for bone tissue engineering.

    PubMed

    Pallela, Ramjee; Venkatesan, Jayachandran; Janapala, Venkateswara Rao; Kim, Se-Kwon

    2012-02-01

    Tricomponent scaffold systems prepared by natural materials especially of marine origin are gaining much attention nowadays for the application in bone tissue engineering. A novel scaffold (Chi-HAp-MSCol) containing chitosan (Chi), hydroxyapatite (HAp) derived from Thunnus obesus bone and marine sponge (Ircinia fusca) collagen (MSCol) was prepared using freeze-drying and lyophilization method. This biomimetic scaffold, along with the Chi and Chi-HAp scaffolds were characterized biophysicochemically for their comparative significance in bone grafting applications. The structural composition of the chitosan, Chi-Hap, and Chi-HAp-MSCol scaffolds were characterized by Fourier Transform Infrared spectroscopy. The porosity, water uptake, and retention abilities of the composite scaffolds decreased, whereas Thermogravimetric and Differential Thermal Analyses results revealed the increase in thermal stability in the scaffold because of the highly stable HAp and MSCol. Homogeneous dispersion of HAp and MSCol in chitosan matrix with interconnected porosity of 60-180 μm (Chi-HAp) and 50-170 μm (Chi-HAp-MSCol) was observed by Scanning Electron Microscopy, X-ray diffraction, and optical microscopy. Cell proliferation in composite scaffolds was relatively higher than pure chitosan when observed by MTT assay and Hoechst staining in vitro using MG-63 cell line. These observations suggest that the novel Chi-HAp-MSCol composite scaffolds are promising biomaterials for matrix-based bone repair and bone augmentation. Copyright © 2011 Wiley Periodicals, Inc.

  5. Chitosan films with improved tensile strength and toughness from N-acetyl-cysteine mediated disulfide bonds.

    PubMed

    Miles, Kevin Barrett; Ball, Rebecca Lee; Matthew, Howard William Trevor

    2016-03-30

    To improve the mechanical properties of chitosan (Ct) materials without the use of cytotoxic crosslinkers, disulfide cross-linkable Ct was synthesized by grafting N-acetyl-cysteine (NAC) to Ct using carbodiimide chemistry. Cast films of NAC-Ct conjugates were prepared with degrees of substitution (DS) of 0%, 6%, 15%, and 20%, and the disulfide bond formation was induced by increasing the reaction media pH to 11. The tensile strength, breaking strain, elastic moduli and toughness of disulfide cross-linked polymers were analyzed by monotonic tensile testing of hydrated NAC-Ct films. Crystallinity was determined via XRD. Results demonstrated that NAC incorporation and crosslinking in chitosan produced tougher polymer films with 4-fold higher tensile strength (10 MPa) and 6-fold greater elongation (365%), but reduced crystallinity, compared to unmodified chitosan. The resilience of NAC-Ct films was evaluated by cyclic testing, and results demonstrate that increasing NAC content produced a more resilient material that dissipated less energy when deformed. These improved mechanical properties broaden chitosan's applicability towards the construction of mechanically robust implantable scaffolds for tissue regeneration.

  6. Pharmacokinetics and biodegradation of chitosan in rats

    NASA Astrophysics Data System (ADS)

    Li, Hui; Jiang, Zhiwen; Han, Baoqin; Niu, Shuyi; Dong, Wen; Liu, Wanshun

    2015-10-01

    Chitosan, an excellent biomedical material, has received a widespread in vivo application. In contrast, its metabolism and distribution once being implanted were less documented. In this study, the pharmacokinetics and biodegradation of fluorescein isothiocyanate (FITC) labeled and muscle implantation administrated chitosan in rats were investigated with fluorescence spectrophotometry, histological assay and gel chromatography. After implantation, chitosan was degraded gradually during its distribution to diverse organs. Among the tested organs, liver and kidney were found to be the first two highest in chitosan content, which was followed by heart, brain and spleen. Urinary excretion was believed to be the major pathway of chitosan elimination, yet 80% of chitosan administered to rats was not trackable in their urine. This indicated that the majority of chitosan was degraded in tissues. In average, the molecular weight of the degradation products of chitosan in diverse organs and urine was found to be <65 kDa. This further confirmed the in vivo degradation of chitosan. Our findings provided new evidences for the intensive and safe application of chitosan as a biomedical material.

  7. Impact of chitosan composites and chitosan nanoparticle composites on various drug delivery systems: A review.

    PubMed

    Elgadir, M Abd; Uddin, Md Salim; Ferdosh, Sahena; Adam, Aishah; Chowdhury, Ahmed Jalal Khan; Sarker, Md Zaidul Islam

    2015-12-01

    Chitosan is a promising biopolymer for drug delivery systems. Because of its beneficial properties, chitosan is widely used in biomedical and pharmaceutical fields. In this review, we summarize the physicochemical and drug delivery properties of chitosan, selected studies on utilization of chitosan and chitosan-based nanoparticle composites in various drug delivery systems, and selected studies on the application of chitosan films in both drug delivery and wound healing. Chitosan is considered the most important polysaccharide for various drug delivery purposes because of its cationic character and primary amino groups, which are responsible for its many properties such as mucoadhesion, controlled drug release, transfection, in situ gelation, and efflux pump inhibitory properties and permeation enhancement. This review can enhance our understanding of drug delivery systems particularly in cases where chitosan drug-loaded nanoparticles are applied. Copyright © 2014. Published by Elsevier B.V.

  8. Calcar bone graft

    SciTech Connect

    Bargar, W.L.; Paul, H.A.; Merritt, K.; Sharkey, N.

    1986-01-01

    A canine model was developed to investigate the use of an autogeneic iliac bone graft to treat the calcar deficiency commonly found at the time of revision surgery for femoral component loosening. Five large male mixed-breed dogs had bilateral total hip arthroplasty staged at three-month intervals, and were sacrificed at six months. Prior to cementing the femoral component, an experimental calcar defect was made, and a bicortical iliac bone graft was fashioned to fill the defect. Serial roentgenograms showed the grafts had united with no resorption. Technetium-99 bone scans showed more uptake at three months than at six months in the graft region. Disulfine blue injection indicated all grafts were perfused at both three and six months. Thin section histology, fluorochromes, and microradiographs confirmed graft viability in all dogs. Semiquantitative grading of the fluorochromes indicated new bone deposition in 20%-50% of each graft at three months and 50%-80% at six months. Although the calcar bone graft was uniformly successful in this canine study, the clinical application of this technique should be evaluated by long-term results in humans.

  9. Hydrophobically modified chitosan/gold nanoparticles for DNA delivery

    NASA Astrophysics Data System (ADS)

    Bhattarai, Shanta Raj; K. C., Remant Bahadur; Aryal, Santosh; Bhattarai, Narayan; Kim, Sun Young; Yi, Ho Keun; Hwang, Pyoung Han; Kim, Hak Yong

    2008-01-01

    Present study dealt an application of modified chitosan gold nanoparticles (Nac-6-Au) for the immobilization of necked plasmid DNA. Gold nanoparticles stabilized with N-acylated chitosan were prepared by graft-onto approach. The stabilized gold nanoparticles were characterized by different physico-chemical techniques such as UV-vis, TEM, ELS and DLS. MTT assay was used for in vitro cytotoxicity of the nanoparticles into three different cell lines (NIH 3T3, CT-26 and MCF-7). The formulation of plasmid DNA with the nanoparticles corresponds to the complex forming capacity and in-vitro/in-vivo transfection efficiency was studied via gel electrophoresis and transfection methods, respectively. Results showed the modified chitosan gold nanoparticles were well-dispersed and spherical in shape with average size around 10˜12 nm in triple distilled water at pH 7.4, and showed relatively no cytotoxicity at low concentration. Addition of plasmid DNA on the aqueous solution of the nanoparticles markedly reduced surface potential (50.0˜66.6%) as well as resulted in a 13.33% increase in hydrodynamic diameters of the formulated nanoparticles. Transfection efficiency of Nac-6-Au/DNA was dependent on cell type, and higher β-galactosidase activity was observed on MCF-7 breast cancer cell. Typically, this activity was 5 times higher in 4.5 mg/ml nanoparticles concentration than that achieved by the nanoparticles of other concentrations (and/or control). However, this activity was lower in in-vitro and dramatically higher in in-vivo than that of commercially available transfection kit (Lipofectin®) and DNA. From these results, it can be expected to develop alternative new vectors for gene delivery.

  10. Grafts in "closed" rhinoplasty.

    PubMed

    Scattolin, A; D'Ascanio, L

    2013-06-01

    Rhinoplasty is a fascinating and complex surgical procedure aiming at attaining a well-functioning and aesthetically pleasant nose. The use of grafts is of the utmost importance for the nasal surgeon to achieve such results. However, the philosophy and technical use of nasal grafts are different in "closed" and "open" rhinoplasty. The aim of this paper is not detailed description of the numerous grafts reported in the literature; we will describe the main principles of grafts use in "closed" rhinoplasty derived from our experience, with special reference to the philosophical and technical differences in their employment between "closed" and "open" rhinoplasty. Some cases are reported as an example of graft use in "endonasal" approach rhinoplasty.

  11. Polymethylmethacrylate combustion in a narrow channel apparatus simulating a microgravity environment

    NASA Astrophysics Data System (ADS)

    Bornand, Garrett Randall

    Fire safety is an important part of engineering when human lives are at stake. From everyday homes to spacecraft that can cost hundreds of millions of dollars. The research in this thesis attempts to provide scientific evidence that the apparatus in question successfully simulates microgravity and can possibly replace NASA's current test method for spacecraft fire safety. Flame spread tests were conducted with thermally thick and thermally thin polymethylmethacrylate (PMMA) samples to study flame spread behavior in response to environmental changes. The tests were conducted using the San Diego State University Narrow Channel Apparatus (SDSU NCA) as well as within the Microgravity Science Glovebox (MSG) on the International Space Station (ISS). The SDSU NCA can suppress buoyant flow in horizontally spreading flames, and is currently being investigated as a possible replacement or complement to NASA's current material flammability test standard for non-metallic solids, NASA-STD-(I)-6001B Test 1. The buoyant suppression attained in the NCA allows tests to be conducted in a simulated microgravity environment-a characteristic that NASA's Test 1 lacks since flames present in Test 1 are driven by buoyant flows. The SDSU NCA allows for tests to be conducted at various opposed flow oxidizer velocities, oxygen percent by volume, and total pressure to mimic various spacecraft and habitat atmospheres. Tests were conducted at 1 atm pressure, thin fuel thickness of 50 and 75 microns, thick fuel thickness ranging from 3 mm to 5.6 mm, opposed oxidizer velocity ranging from 10 to 25 cm/s, and oxygen concentration by volume at 21, 30, and 50 percent. The simulated microgravity flame spread results were then compared to true microgravity experiments including; testing conducted on the International Space Station (ISS) under the Burning and Suppression of Solids (BASS) research, NASA's 5.2 second Drop Tower, and Micro-Gravity Laboratory's (MGLAB) 4.5 second Drop Tower. Data was also

  12. Single molecule detection of double-stranded DNA in poly(methylmethacrylate) and polycarbonate microfluidic devices.

    PubMed

    Wabuyele, M B; Ford, S M; Stryjewski, W; Barrow, J; Soper, S A

    2001-10-01

    Single photon burst techniques were used to detect double-stranded DNA molecules in poly(methylmethacrylate) (PM MA) and polycarbonate (PC) microfluidic devices. A confocal epi-illumination detection system was constructed to monitor the fluorescence signature from single DNA molecules that were multiply labeled with the mono-intercalating dye, TOPRO-5, which possessed an absorption maximum at 765 nm allowing excitation with a solid-state diode laser and fluorescence monitoring in the near-infrared (IR). Near-IR excitation minimized autofluorescence produced from the polymer substrate, which was found to be significantly greater when excitation was provided in the visible range (488 nm). A solution containing lambda-DNA (48.5 kbp) was electrokinetically transported through the microfluidic devices at different applied voltages and solution pH values to investigate the effects of polymer substrate on the transport rate and detection efficiency of single molecular events. By applying an autocorrelation analysis to the data, we were able to obtain the molecular transit time of the individual molecules as they passed through the 7 microm laser beam. It was observed that the applied voltage for both devices affected the transport rate. However, solution pH did not alter the transit time for PM MA-based devices since the electroosmotic flow of PMMA was independent of solution pH. In addition, efforts were directed toward optimizing the sampling efficiency (number of molecules passing through the probe volume) by using either hydrodynamically focused flows from a sheath generated by electrokinetic pumping from side channels or reducing the channel width of the microfluidic device. Due to the low electroosmotic flows generated by both PMMA and PC, tight focusing of the sample stream was not possible. However, in PMMA devices, flow gating was observed by applying field strengths > -120 V/cm to the sheath flow channels. By narrowing the microchannel width, the number of

  13. Preparation and characterization of hydroxypropyl chitosan modified with collagen peptide.

    PubMed

    Fan, Lihong; Zou, Shengqiong; Ge, Hongyu; Xiao, Yao; Wen, Huigao; Feng, Han; Liu, Meng; Nie, Min

    2016-12-01

    Collagen peptide (COP) had been grafted to hydroxypropyl chitosan (HPCS) by using microbial transglutaminase (MTGase) as biocatalyst. HPCS was synthesized from chitosan and propylene oxide under alkali condition. The chemical structures of derivative were characterized by FT-IR and (1)H NMR spectroscopy. The process conditions were optimized from the aspects of the reaction time, the reaction temperature, the molar ratio of COP and the mass ratio of MTGase to HPCS. In this study, HPCS-COP could serve not only to reduce the loss of moisture but also to absorb the moisture, and the moisture absorption and moisture retention abilities were closely related to the degree of substitution (DS) values. In addition, with the DS and concentration increase of HPCS-COP, the radical scavenging activity increased in vitro antioxidant activity. Furthermore, the methyl thiazolyl tetrazolium assay (MTT) was applied to evaluate the biocompatibility of HPCS-COP, and the result indicated that HPCS-COP with the DS of 0.34 displayed pronounced cell viability at 50ppm. Therefore, the results suggest that HPCS-COP could be potential wound dressings for clinical applications. Copyright © 2016 Elsevier B.V. All rights reserved.

  14. Photoactive chitosan switching on bone-like apatite deposition.

    PubMed

    Chiono, Valeria; Gentile, Piergiorgio; Boccafoschi, Francesca; Carmagnola, Irene; Ninov, Momchil; Georgieva, Ventsislava; Georgiev, George; Ciardelli, Gianluca

    2010-02-08

    The work was focused on the synthesis and characterization of the chitosan-g-fluorescein (CHFL) conjugate polymer as a biocompatible amphiphilic water-soluble photosensitizer, able to stimulate hydroxyapatite deposition upon visible light irradiation. Fluorescein (FL) grafting to chitosan (CH) chains was confirmed by UV-vis analysis of water solutions of FL and CHFL and by Fourier transform infrared spectroscopy (FTIR-ATR) analysis of CHFL and CH. Smooth CHFL cast films with 4 microm thickness were obtained by solvent casting. Continuous exposure to visible light for 7 days was found to activate the deposition of calcium phosphate crystals from a conventional simulated body fluid (SBF 1.0x) on the surface of CHFL cast films. EDX and FTIR-ATR analyses confirmed the apatite nature of the deposited calcium phosphate crystals. CHFL films preincubated in SBF (1.0x) solution under visible light irradiation and in the dark for 7 days were found to support the in vitro adhesion and proliferation of MG63 osteoblast-like cells (MTT viability test; 1-3 days culture time). On the other hand, the mineralization ability of MG63 osteoblast-like cells was significantly improved on CHFL films preincubated under visible light exposure (alkaline phosphatase activity (ALP) test for 1, 3, 7, and 14 days). The use of photoactive biocompatible conjugate polymer, such as CHFL, may lead to new therapeutic options in the field of bone/dental repair, exploiting the photoexcitation mechanism as a tool for biomineralization.

  15. Amphiphilically modified chitosan cationic nanoparticles for drug delivery

    NASA Astrophysics Data System (ADS)

    You, Jie; Li, Wenfeng; Yu, Chang; Zhao, Chengguang; Jin, Langping; Zhou, Yili; Xu, Xuzhong; Dong, Siyang; Lu, Xincheng; Wang, Ouchen

    2013-12-01

    A series of amphiphilic N-(2-hydroxy)propyl-3-trimethylammonium-chitosan-cholic acid (HPTA-CHI-CA) polymers were synthesized by grafting cholic acid (CA) and glycidyltrimethylammonium chloride onto chitosan. The self-assembly behavior of HPTA-CHI-CA was studied by fluorescence technique. The polymers were able to self-assemble into NPs in phosphate buffered saline with a critical aggregation concentration (CAC) in the range of 66-26 mg/L and the CAC decreased with the increasing of the degree of substitution (DS) of CA. The size of cationic HPTA-CHI-CA NPs ranges from 170 to 220 nm (PDI < 0.2). It was found that doxorubicin (DOX) could be encapsulated into HPTA-CHI-CA NPs based on self-assembly. The drug loading content and efficiency varies depending on the DS of CA and feeding ratio of DOX to polymer. In vitro release studies suggested that DOX released slowly from HPTA-CHI-CA NPs without any burst initial release. Besides, the confocal microscopic measurements indicated that DOX-HPTA-CHI-CA NPs could easily be uptaken by breast cancer (MCF-7) cells and release DOX in cytoplasm. Anti-tumor efficacy results showed that DOX-HPTA-CHI-CA NPs have a significant activity of inhibition MCF-7 cells growth. These results suggest cationic HPTA-CHI-CA may have great potential for anticancer drug delivery.

  16. Radiation depolymerization of chitosan to prepare oligomers

    NASA Astrophysics Data System (ADS)

    Hai, Le; Bang Diep, Tran; Nagasawa, Naotsugu; Yoshii, Fumio; Kume, Tamikazu

    2003-08-01

    Radiation depolymerization of chitosan was carried out by gamma irradiation in the solid state. The radiation-chemical depolymerization yield of chitosan in the solid state, Gd, determined by gel permeation chromatography, is 0.9 for chitosan 10B and 1.8 for chitosan 8B. Low molecular weight chitosan/or oligochitosans were separated from a chitosan depolymerized by gamma radiation, using mixtures of methanol-water and acetone as the solvents. Due to the differences in solubility revealed upon radiolysis, extracts became subdivided into precipitates and soluble fractions. The biological effect of oligochitosan in each fraction was evaluated; the preliminary results indicated that the oligochitosan with overlineM w=2×10 4 inhibited the growth of fungi at 100 ppm and that with overlineM w=800 only enhanced the growth of the same typical fungi.

  17. Chitosan Modification and Pharmaceutical/Biomedical Applications

    PubMed Central

    Zhang, Jiali; Xia, Wenshui; Liu, Ping; Cheng, Qinyuan; Tahirou, Talba; Gu, Wenxiu; Li, Bo

    2010-01-01

    Chitosan has received much attention as a functional biopolymer for diverse applications, especially in pharmaceutics and medicine. Our recent efforts focused on the chemical and biological modification of chitosan in order to increase its solubility in aqueous solutions and absorbability in the in vivo system, thus for a better use of chitosan. This review summarizes chitosan modification and its pharmaceutical/biomedical applications based on our achievements as well as the domestic and overseas developments: (1) enzymatic preparation of low molecular weight chitosans/chitooligosaccharides with their hypocholesterolemic and immuno-modulating effects; (2) the effects of chitin, chitosan and their derivatives on blood hemostasis; and (3) synthesis of a non-toxic ion ligand—D-Glucosaminic acid from Oxidation of D-Glucosamine for cancer and diabetes therapy. PMID:20714418

  18. Carboxyl-modified poly(vinyl alcohol)-crosslinked chitosan hydrogel films for potential wound dressing.

    PubMed

    Zhang, Di; Zhou, Wei; Wei, Bing; Wang, Xin; Tang, Rupei; Nie, Jiemin; Wang, Jun

    2015-07-10

    The objective of this study was to develop a novel carboxyl-modified poly(vinyl alcohol)-crosslinked chitosan hydrogel films for potential wound dressing. To prepare the crosslinked hydrogels, poly(vinyl alcohol) (PVA) was grafted with succinate acid to yield carboxyl-modified poly(vinyl alcohol) (PVA-COOH). Hydrogel films based on PVA-COOH and chitosan (CS) at different concentrations were crosslinked through the formation of amide linkages. The mechanical properties of these crosslinked hydrogel films in dry and swollen state were greatly improved with high swelling ratio. Water vapor and oxygen permeability evaluations indicated that crosslinked hydrogel films could maintain a moist environment over wound bed. Biocompatibility test showed the crosslinked hydrogels had no cytotoxicity and hemolytic potential. Gentamicin sulfate-loaded crosslinked hydrogel films showed sustained drug release profile, and could effectively suppress bacterial proliferation and protect wound from infection.

  19. Preparation and biological activity of quaternized carboxymethyl chitosan conjugated with collagen peptide.

    PubMed

    Zhu, Xiaoming; Zhou, Xiaoyu; Yi, Jiayan; Tong, Jun; Wu, Huan; Fan, Lihong

    2014-09-01

    Tissue repair is a spontaneous process which initiated on wounding. If this complex mechanism is disturbed or impaired, the use of biomaterials might increase the chance of successful healing. In this view, a water-soluble chitosan derivative, quaternized carboxymethyl chitosan (QCMC) was prepared and collagen peptides (COPs) were grafted to the backbone by carbodiimide method. The reaction conditions affecting the degree of substitution (DS) were studied including the mass ratio of collagen peptide to QCMC, reaction temperature and reaction time. The hydrogen peroxide-scavenging activity could be different by changing the DS, concentration and molecular weight. MTT assay was used to investigate the cell viability of the derivative. The results indicated that the introduction of collagen peptide into the QCMC improved its hydrogen peroxide-scavenging activity and cell viability with the DS and concentration increased. Therefore, QCMC conjugated with collagen peptides may prove beneficial to the process of the wound-healing.

  20. Incorporation of Chitosan Microspheres into Collagen-Chitosan Scaffolds for the Controlled Release of Nerve Growth Factor

    PubMed Central

    Xiao, Wei; Qi, Fengyu; Huang, Jinghui; Luo, Zhuojing

    2014-01-01

    Background Artifical nerve scaffold can be used as a promising alternative to autologous nerve grafts to enhance the repair of peripheral nerve defects. However, current nerve scaffolds lack efficient microstructure and neurotrophic support. Methods Microsphere–Scaffold composite was developed by incorporating chitosan microspheres loaded with nerve growth factor (NGF–CMSs) into collagen-chitosan scaffolds (CCH) with longitudinally oriented microchannels (NGF–CMSs/CCH). The morphological characterizations, in vitro release kinetics study, neurite outgrowth assay, and bioactivity assay were evaluated. After that, a 15-mm-long sciatic nerve gap in rats was bridged by the NGF–CMSs/CCH, CCH physically absorbed NGF (NGF/CCH), CCH or nerve autograft. 16 weeks after implantation, electrophysiology, fluoro-gold retrograde tracing, and nerve morphometry were performed. Results The NGF–CMSs were evenly distributed throughout the longitudinally oriented microchannels of the scaffold. The NGF–CMSs/CCH was capable of sustained release of bioactive NGF within 28 days as compared with others in vitro. In vivo animal study demonstrated that the outcomes of NGF–CMSs/CCH were better than those of NGF/CCH or CCH. Conclusion Our findings suggest that incorporation of NGF–CMSs into the CCH may be a promising tool in the repair of peripheral nerve defects. PMID:24983464

  1. Vitamin D-fortified chitosan films from mushroom waste.

    PubMed

    Bilbao-Sainz, Cristina; Chiou, Bor-Sen; Williams, Tina; Wood, Delilah; Du, Wen-Xian; Sedej, Ivana; Ban, Zhaojun; Rodov, Victor; Poverenov, Elena; Vinokur, Yakov; McHugh, Tara

    2017-07-01

    Brown mushroom (Agaricus bisporus) stalk bases from mushroom waste were treated with UV-B light to rapidly increase vitamin D2 content. Chitin was also recovered from this waste and converted into chitosan by N-deacetylation. FTIR spectra showed that the mushroom chitosan were similar to chitosan from animal sources. Chitosan films were prepared using high molecular weight (HW), low molecular weight (LW) and fungal chitosan. UV-B treated mushroom particles were also incorporated into fungal chitosan films. The fungal chitosan films showed similar density, porosity and water vapor barrier properties to the LW and HW chitosan films. However, fungal chitosan films were more hydrophobic and less flexible than the LW and HW chitosan films. Addition of mushroom particles did not significantly affect mechanical or water barrier properties of the fungal chitosan films. Published by Elsevier Ltd.

  2. Effects of polymethylmethacrylate-transfer residues on the growth of organic semiconductor molecules on chemical vapor deposited graphene

    SciTech Connect

    Kratzer, Markus Teichert, Christian; Bayer, Bernhard C.; Kidambi, Piran R.; Matković, Aleksandar; Gajić, Radoš; Cabrero-Vilatela, Andrea; Weatherup, Robert S.; Hofmann, Stephan

    2015-03-09

    Scalably grown and transferred graphene is a highly promising material for organic electronic applications, but controlled interfacing of graphene thereby remains a key challenge. Here, we study the growth characteristics of the important organic semiconductor molecule para-hexaphenyl (6P) on chemical vapor deposited graphene that has been transferred with polymethylmethacrylate (PMMA) onto oxidized Si wafer supports. A particular focus is on the influence of PMMA residual contamination, which we systematically reduce by H{sub 2} annealing prior to 6P deposition. We find that 6P grows in a flat-lying needle-type morphology, surprisingly independent of the level of PMMA residue and of graphene defects. Wrinkles in the graphene typically act as preferential nucleation centers. Residual PMMA does however limit the length of the resulting 6P needles by restricting molecular diffusion/attachment. We discuss the implications for organic device fabrication, with particular regard to contamination and defect tolerance.

  3. Memory effects of nonvolatile memory devices with a floating gate fabricated utilizing Ag nanoparticles embedded into a polymethylmethacrylate layer.

    PubMed

    Kim, Won Tae; Yun, Dong Yeol; Jung, Jae Hun; Kim, Tae Whan

    2011-01-01

    Nonvolatile memory devices based on a polymethylmethacrylate (PMMA) layer containing Ag nanoparticles were formed by using a spin coating method. High-resolution transmission electron microscopy images showed that Ag nanoparticles were randomly distributed in the PMMA layer. Capacitance-voltage (C-V) curves for the Al/Ag nanoparticles embedded in a PMMA layer/p-Si(100) device at 300 K showed a hysteresis with a large flat-band voltage shift, indicative of the Ag nanoparticles acting as the charge storage in the memory device. The magnitude of the flat-band voltage shift for the memory devices increased with increasing Ag nanoparticle concentration. The operating mechanisms for the writing and the erasing processes for the Al/Ag nanoparticles embedded in a PMMA layer/p-Si(100) device are described on the basis of the C-V results and electronic structures.

  4. Microwave-assisted surface modification for the separation of polycarbonate from polymethylmethacrylate and polyvinyl chloride waste plastics by flotation.

    PubMed

    Huang, Luoluo; Wang, Hui; Wang, Chongqing; Zhao, Junyao; Zhang, Bo

    2017-03-01

    Microwave-assisted potassium permanganate modification (MPPM) was used for the flotation separation of polycarbonate (PC) from polyvinyl chloride (PVC) and polymethylmethacrylate (PMMA) waste plastics. The separation process was optimized by investigating the potassium permanganate concentration, treatment time, flotation time and frother concentration. MPPM selectively reduced the flotation recovery of PC. The optimum conditions were determined to be: potassium permanganate concentration, 2 mM/L; treatment time, 1 min; frother concentration, 17.57 g/L; and flotation time, 1 min. PC was efficiently separated from PVC and PMMA under the optimum conditions. The purity of the separated PC was 97.71%. The purity and recovery of PVC and PMMA were both >95%. The modification mechanism was investigated using the water contact angles, Fourier transform infrared spectrometry and scanning electron microscopy. This work provides technical insights into the industrial recycling of waste plastics.

  5. High-performance nonvolatile write-once-read-many-times memory devices with ZnO nanoparticles embedded in polymethylmethacrylate

    NASA Astrophysics Data System (ADS)

    Thanh Dao, Toan; Viet Tran, Thu; Higashimine, Koichi; Okada, Hiromasa; Mott, Derrick; Maenosono, Shinya; Murata, Hideyuki

    2011-12-01

    A mixture of ZnO nanoparticles and polymethylmethacrylate was used as an active layer in a nonvolatile resistive memory device. Current-voltage characteristics of the device showed nonvolatile write-once-read-many-times memory behavior with a switching time on the order of μs. The device exhibited an on/off ratio of 104, retention time of >105 s, and number of readout of >4 × 104 times under a read voltage of 0.5 V. The emission, cross-sectional high-resolution transmission electron microscopy (TEM), scanning TEM-high angle annular dark field imaging, and energy dispersive x-ray spectroscopy elemental mapping measurements suggest that the electrical switching originates from the formation of conduction paths.

  6. Delayed granulomatous reactions to facial cosmetic injections of polymethylmethacrylate microspheres and liquid injectable silicone: A case series.

    PubMed

    Friedmann, Daniel P; Kurian, Anil; Fitzpatrick, Richard E

    2016-06-01

    Polymethylmethacrylate microsphere (PMMA) and liquid injectable silicone (LIS) fillers are non-biodegradable, synthetic polymers utilized for long-term soft-tissue augmentation. Delayed granulomatous reactions to permanent fillers are a rare yet significant event that can occur months to years post procedure and are often refractory to treatment and associated with significant cosmetic morbidity. We report a case series of 4 patients who developed granulomatous reactions to PMMA or LIS, 15 months to 5 years post injection. The etiology of granulomatous reactions to permanent fillers is still poorly understood, with foreign-body reactions and/or biofilms purported to play a role. Real-time biochemical analysis with polymerase chain reaction should be performed when the index of suspicion for the presence of a biofilm is high.

  7. Nanoindentation of Chitosan Doped with Silver Nanoparticles

    NASA Astrophysics Data System (ADS)

    Palumbo, Matthew; Teklu, Alem; Kuthirummal, Narayanan; Levi-Polyachenko, Nicole; Department of Physics; Astronomy, College of Charleston Collaboration; Department of Plastic; Reconstructive Surgery, Wake Forest University Health Sciences Collaboration

    Imaging and spectroscopic analysis via nanoindentation was performed with the Nanosurf EasyScan2 AFM on the pure and silver doped chitosan samples allowing for a more localized determination of their stiffness, hardness, and reduced Young's modulus. The pure chitosan sample was tested to have a stiffness of 0.367 N/m, a hardness of 1.12 GPa, and a reduced Young's modulus of 30.5 MPa. The film with 5mg Ag nanoparticle per gram of chitosan was tested on the boundaries between the chitosan and Ag nanoparticles to show an increase in stiffness of about 4.6% at 0.384 N/m, an increase in hardness of about 5.4% at 1.18 GPa, and an increase in the reduced Young's modulus of about 5.0% at 3.2 MPa in comparison to the pure chitosan sample. On the other hand, upon increasing the doping to 10mg Ag nanoparticle per gram of chitosan showed a decrease in stiffness of about 6.3% at 0.344 N/m, a decrease in hardness of about 27.0% at 0.820 GPa, and a decrease in the reduced Young's modulus of about 6.0% at 28.7 MPa in comparison to the pure chitosan sample. Obviously, films doped with 5mg Ag nanoparicle per gram of chitosan provided the composites with improved mechanical strength compared to chitosan alone.

  8. Novel naturally crosslinked electrospun nanofibrous chitosan mats for guided bone regeneration membranes: material characterization and cytocompatibility.

    PubMed

    Norowski, Peter A; Fujiwara, Tomoko; Clem, William C; Adatrow, Pradeep C; Eckstein, Eugene C; Haggard, Warren O; Bumgardner, Joel D

    2015-05-01

    Guided bone regeneration (GBR) barrier membranes are used to prevent soft tissue infiltration into the graft space during dental procedures that involve bone grafting. Chitosan materials have shown promise as GBR barrier membranes, due to their biocompatibility and predictable biodegradability, but degradation rates may still be too high for clinical applications. In this study, chitosan GBR membranes were electrospun using chitosan (70% deacetylated, 312 kDa, 5.5 w/v%), with or without the addition of 5 or 10 mm genipin, a natural crosslinking agent, in order to extend the degradation to meet the clinical target time frame of 4-6 months. Membranes were evaluated for fibre diameter, tensile strength, biodegradation rate, bond structure and cytocompatibility. Genipin addition, at 5 or 10 mm, resulted in median fibre diameters 184, 144 and 154 nm for uncrosslinked, 5 mm and 10 mm crosslinked, respectively. Crosslinking, examined by Fourier transform infrared spectroscopy, showed a decrease in N-H stretch as genipin levels were increased. Genipin-crosslinked mats exhibited only 22% degradation based on mass loss, as compared to 34% for uncrosslinked mats at 16 weeks in vitro. The ultimate tensile strength of the mats was increased by 165% to 32 MPa with 10 mm crosslinking as compared to the uncrosslinked mats. Finally, genipin-crosslinked mats supported the proliferation of SAOS-2 cells in a 5 day growth study, similar to uncrosslinked mats. These results suggest that electrospun chitosan mats may benefit from genipin crosslinking and have the potential to meet clinical degradation time frames for GBR applications.

  9. The role of mucoadhesion of trimethyl chitosan and PEGylated trimethyl chitosan nanocomplexes in insulin uptake.

    PubMed

    Jintapattanakit, Anchalee; Junyaprasert, Varaporn Buraphacheep; Kissel, Thomas

    2009-12-01

    The aim of this work was to investigate the role of mucoadhesion in the insulin uptake of nanocomplexes (NC) based of trimethyl chitosan (TMC) and poly(ethylene glycol) (PEG)-graft-TMC copolymers. Self-assembled insulin NC were prepared by polyelectrolyte complexation. The effects of PEGylation and positive charge density on mucoadhesion were assessed using a mucin assay and mucus-secreting HT29-MTX-E12 (E12) monolayers. The behaviors of corresponding insulin NC after adhesion to E12 were also established. All PEGylated TMC copolymers showed significantly higher levels of adhesion to mucus than unmodified TMC. The copolymer composed of 298 PEG chains per TMC macromolecules exhibited the highest level of mucoadhesion, being 3.4 times higher than TMC. The higher mucoadhesive properties of PEGylated TMC copolymers resulted from the synergistic effects of interpenetration of PEG chains into the mucus and electrostatic interaction between positive charged TMC and anionic glycoproteins present in the mucus layer. Compared to TMC, insulin NC based on PEGylated TMC copolymers demonstrated no evidence of insulin uptake improvement due to complete release of insulin from NC after adhering to mucus. CLSM revealed the localization of TMC and its corresponding insulin NC at cell surface membranes of E12.

  10. Neuroregeneration of Induced Pluripotent Stem Cells in Polyacrylamide-Chitosan Inverted Colloidal Crystal Scaffolds with Poly(lactide-co-glycolide) Nanoparticles and Transactivator of Transcription von Hippel-Lindau Peptide.

    PubMed

    Kuo, Yung-Chih; Chen, Chun-Wei

    2017-04-01

    Polyacrylamide (PAAM) and chitosan were fabricated by inverted colloidal crystal (ICC) method for scaffolds comprising regular pores. The hybrid PAAM-chitosan ICC scaffolds were grafted with poly(lactide-co-glycolide) (PLGA) nanoparticles (NPs) for a rougher pore surface and grafted with transactivator of transcription von Hippel-Lindau (TATVHL) peptide for a better differentiation of induced pluripotent stem (iPS) cells toward neural lineage. By scanning electron microscopy, we found that iPS cells cultured in PAAM-chitosan ICC scaffolds with PLGA NPs at 1.0 mg/mL and TATVHL peptide at 15 μg/mL elongated the axonal length to 15 μm. A combination of PLGA NPs and TATVHL peptide favored the adhesion of iPS cells, reduced the embryonic phenotype after cultivation, and guided the production of βIII tubulin-positive cells in PAAM-chitosan ICC scaffolds. In addition to the differentiation toward neurite-like cells, an increase in the content of TATVHL peptide in PAAM-chitosan ICC scaffolds inhibited the differentiation of iPS cells toward astrocytes. ICC scaffolds composed of PAAM, chitosan, PLGA NPs, and TATVHL peptide can be an efficacious matrix to differentiate iPS cells toward neurons and retard the glial formation for nerve regeneration.

  11. Evaluation of fluorescence in situ hybridization to detect encapsulated Bacillus pumilus SAFR-032 spores released from poly(methylmethacrylate).

    PubMed

    Mohapatra, Bidyut R; La Duc, Myron T

    2012-01-01

    Bacillus pumilus SAFR-032 spores originally isolated from the Jet Propulsion Laboratory spacecraft assembly facility clean room are extremely resistant to UV radiation, H(2)O(2), desiccation, chemical disinfection and starvation compared to spores of other Bacillus species. The resistance of B. pumilus SAFR-032 spores to standard industrial clean room sterilization practices is not only a major concern for medical, pharmaceutical and food industries, but also a threat to the extraterrestrial environment during search for life via spacecraft. The objective of the present study was to investigate the potential of Alexa-FISH (fluorescence in situ hybridization with Alexa Fluor® 488 labeled oligonucleotide) method as a molecular diagnostic tool for enumeration of multiple sterilant-resistant B. pumilus SAFR-032 spores artificially encapsulated in, and released via organic solvent from, a model polymeric material: poly(methylmethacrylate) (Lucite, Plexiglas). Plexiglas is used extensively in various aerospace applications and in medical, pharmaceutical and food industries. Alexa-FISH signals were not detected from spores via standard methods for vegetative bacterial cells. Optimization of a spore permeabilization protocol capitalizing on the synergistic action of proteinase-K, lysozyme, mutanolysin and Triton X-100 facilitated efficient spore detection by Alexa-FISH microscopy. Neither of the Alexa-probes tested gave rise to considerable levels of Lucite- or solvent-associated background autofluorescence, demonstrating the immense potential of Alexa-FISH for rapid quantification of encapsulated B. pumilus SAFR-032 spores released from poly(methylmethacrylate). © 2012 The Societies and Blackwell Publishing Asia Pty Ltd.

  12. A Signal-Inducing Bone Cement for Magnetic Resonance Imaging-Guided Spinal Surgery Based on Hydroxyapatite and Polymethylmethacrylate

    SciTech Connect

    Wichlas, Florian Seebauer, Christian J.; Schilling, Rene; Rump, Jens; Chopra, Sascha S.; Walter, Thula; Teichgraeber, Ulf K. M.; Bail, Hermann J.

    2012-06-15

    The aim of this study was to develop a signal-inducing bone cement for magnetic resonance imaging (MRI)-guided cementoplasty of the spine. This MRI cement would allow precise and controlled injection of cement into pathologic lesions of the bone. We mixed conventional polymethylmethacrylate bone cement (PMMA; 5 ml methylmethacrylate and 12 g polymethylmethacrylate) with hydroxyapatite (HA) bone substitute (2-4 ml) and a gadolinium-based contrast agent (CA; 0-60 {mu}l). The contrast-to-noise ratio (CNR) of different CA doses was measured in an open 1.0-Tesla scanner for fast T1W Turbo-Spin-Echo (TSE) and T1W TSE pulse sequences to determine the highest signal. We simulated MRI-guided cementoplasty in cadaveric spines. Compressive strength of the cements was tested. The highest CNR was (1) 87.3 (SD 2.9) in fast T1W TSE for cements with 4 {mu}l CA/ml HA (4 ml) and (2) 60.8 (SD 2.4) in T1W TSE for cements with 1 {mu}l CA/ml HA (4 ml). MRI-guided cementoplasty in cadaveric spine was feasible. Compressive strength decreased with increasing amounts of HA from 46.7 MPa (2 ml HA) to 28.0 MPa (4 ml HA). An MRI-compatible cement based on PMMA, HA, and CA is feasible and clearly visible on MRI images. MRI-guided spinal cementoplasty using this cement would permit direct visualization of the cement, the pathologic process, and the anatomical surroundings.

  13. An in vitro study to compare the transverse strength of thermopressed and conventional compression-molded polymethylmethacrylate polymers.

    PubMed

    Raut, Anjana; Rao, Polsani Laxman; Vikas, B V J; Ravindranath, T; Paradkar, Archana; Malakondaiah, G

    2013-01-01

    Acrylic resins have been in the center stage of Prosthodontics for more than half a century. The flexural fatigue failure of denture base materials is the primary mode of clinical failure. Hence there is a need for superior physical and mechanical properties. This in vitro study compared the transverse strength of specimens of thermopressed injection-molded and conventional compression-molded polymethylmethacrylate polymers and examined the morphology and microstructure of fractured acrylic specimens. The following denture base resins were examined: Brecrystal (Thermopressed injection-molded, modified polymethylmethacrylate) and Pyrax (compression molded, control group). Specimens of each material were tested according to the American Society for Testing and Materials standard D790-03 for flexural strength testing of reinforced plastics and subsequently examined under SEM. The data was analyzed with Student unpaired t test. Flexural strength of Brecrystal (82.08 ± 1.27 MPa) was significantly higher than Pyrax (72.76 ± 0.97 MPa). The tested denture base materials fulfilled the requirements regarding flexural strength (>65 MPa). The scanning electron microscopy image of Brecrystal revealed a ductile fracture with crazing. The fracture pattern of control group specimens exhibited poorly defined crystallographic planes with a high degree of disorganization. Flexural strength of Brecrystal was significantly higher than the control group. Brecrystal showed a higher mean transverse strength value of 82.08 ± 1.27 MPa and a more homogenous pattern at microscopic level. Based on flexural strength properties and handling characteristics, Brecrystal may prove to be an useful alternative to conventional denture base resins.

  14. Preparation of chitosan nanofibers from completely deacetylated chitosan powder by a downsizing process.

    PubMed

    Aklog, Yihun Fantahun; Dutta, Ajoy Kumar; Izawa, Hironori; Morimoto, Minoru; Saimoto, Hiroyuki; Ifuku, Shinsuke

    2015-01-01

    Chitosan nanofibers were easily prepared from fully deacetylated chitosan dry powder using a high-pressure waterjet system. From SEM observation, after 10 cycles of treatment, most of the chitosan had been reduced to homogeneous nanofibers measuring tens of nanometers. On the other hand, further mechanical treatment did not show a significant change. Relative crystallinity of chitosan nanofibers gradually decreased as the number of passes increased since high-pressure waterjet treatment damaged the crystalline region of chitosan nanofibers. The transmittance of the chitosan nanofiber slurry increased steeply, as the number of passes increased, indicating that the chitosan fibers were disintegrated effectively. Viscosity of chitosan nanofiber slurry also showed that the chitosan disintegrated well into nanofibers up to 10 passes. Above 10 passes, disintegration efficiency was saturated. The molecular weights of the nanofibers steeply decreased due to the depolymerization of chitosan by mechanical disintegration. The Young's modulus and tensile strength of chitosan nanofiber sheets were improved as the number of treatments increased, but further treatments deteriorated the tensile strength.

  15. Mucoadhesion mechanism of chitosan and thiolated chitosan-poly(isobutyl cyanoacrylate) core-shell nanoparticles.

    PubMed

    Bravo-Osuna, Irene; Vauthier, Christine; Farabollini, Alessandra; Palmieri, Giovanni Filippo; Ponchel, Gilles

    2007-04-01

    The study is focused on the evaluation of the potential bioadhesive behaviour of chitosan and thiolated chitosan (chitosan-TBA)-coated poly(isobutyl cyanoacrylates) (PIBCA) nanoparticles. Nanoparticles were obtained by radical emulsion polymerisation with chitosan of different molecular weight and with different proportions of chitosan/chitosan-TBA. Mucoadhesion was ex vivo evaluated under static conditions by applying nanoparticle suspensions on rat intestinal mucosal surfaces and evaluating the amount of nanoparticles remaining attached to the mucosa after incubation. The analysis of the results obtained demonstrated that the presence of either chitosan or thiolated chitosan on the PIBCA nanoparticle surface clearly enhanced the mucoadhesion behaviour thanks to non-covalent interactions (ionic interaction and hydrogen bonds) with mucus chains. Both, the molecular weight of chitosan and the proportion of chitosan-TBA in the formulation influenced the nanoparticle hydrodynamic diameter and hence their transport through the mucus layer. Improved interpenetration ability with the mucus chain during the attachment process was suggested for the chitosan of high molecular weight, enhancing the bioadhesiveness of the system. The presence of thiol groups on the nanoparticle surface at high concentration (200 x 10(-6) micromol SH/cm2) increased the mucoadhesion capacity of nanoparticles by forming covalent bonds with the cysteine residues of the mucus glycoproteins.

  16. [Research of bio-performance of chitosan and chitosan being used for bacterial vaginosis].

    PubMed

    Cui, Huisu; Shi, Wei

    2012-03-01

    Discussing the chitosan' medical efficiency to treat Gynecology bacteria infectious disease by researching the bacteriostasis, biocompatibility of chitosan and analyzing the chitosan' medical efficiency to Bacterial vaginosis by clinical examination. The antibiotic experiment of chitosan to Candida albicans (ATCC 10231), Escherichia Coli (ATCC 25922) and Golden staphylococcus (ATCC 6538) has been studied in this paper. The vaginal irritation experimentation of chitosan to female rabbit and the sensitization experimentation of chitosan to guinea pig also have been conducted. To study the curative effect, we also coat a layer of chitosan in 20 patients' vagina. The Antibacterial rate of chitosan to Candida albicans is more than 98% and to Escherichia Coli is more than 99% and to Golden staphylococcus is more than 99%. Cytotoxicity of chitosan to vagina mucosa is grade 1 and sensitization of chitosan to vagina mucosa is none and stimulation of chitosan to vagina mucosa is very slightly. The total efficiency rate to treat Gynecology bacteria infectious disease is 90% and the cure rate is 75%.

  17. Antibacterial hydrogel coating by electrophoretic co-deposition of chitosan/alkynyl chitosan.

    PubMed

    Ding, Fuyuan; Nie, Zhen; Deng, Hongbing; Xiao, Ling; Du, Yumin; Shi, Xiaowen

    2013-11-06

    Despite much effort has been paid to develop aseptic implant devices, the infection associated with medical implant still remains a significant problem. Here, we report a potential coating material derived from a natural biopolymer chitosan. Firstly, chitosan functionalized with alkynyl moiety (ACS) was prepared by reaction between chitosan and 3-bromopropyne. The structure of the alkynyl chitosan was characterized by FT-IR, (1)H NMR, XRD, TGA and element analysis. The minimum inhibitory concentration (MIC) of ACS with a degree of substitution (DS) of 0.40 was 0.03% against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). Subsequently, the alkynyl chitosan was co-deposited with chitosan on stainless steel wire to fabricate a composite hydrogel. The composite hydrogel exhibited better antibacterial activities than pure chitosan hydrogel.

  18. Skin graft - slideshow

    MedlinePlus

    ... ency/presentations/100100.htm Skin graft - series—Normal anatomy To use the sharing features on this page, ... 2017 Updated by: Debra G. Wechter, MD, FACS, general surgery practice specializing in breast cancer, Virginia Mason ...

  19. Vein graft failure

    PubMed Central

    Owens, Christopher D.; Gasper, Warren J.; Rahman, Amreen S.; Conte, Michael S

    2013-01-01

    Following the creation of an autogenous lower extremity bypass graft, the vein must undergo a series of dynamic structural changes to stabilize the arterial hemodynamic forces. These changes, commonly referred to as remodeling, include an inflammatory response, the development of a neointima, matrix turnover, and cellular proliferation and apoptosis. The sum total of these processes results in dramatic alterations in the physical and biomechanical attributes of the arterialized vein. The most clinically obvious and easily measured of these is lumen remodeling of the graft. However, though somewhat less precise, wall thickness, matrix composition, and endothelial changes can be measured in vivo within the healing vein graft. Recent translational work has demonstrated the clinical relevance of remodeling as it relates to vein graft patency and the systemic factors influencing it. By correlating histologic and molecular changes in the vein, insights into potential therapeutic strategies to prevent bypass failure and areas for future investigation are explored. PMID:24095042

  20. Electrical regulation of olfactory ensheathing cells using conductive polypyrrole/chitosan polymers.

    PubMed

    Qi, Fengyu; Wang, Yuqing; Ma, Teng; Zhu, Shu; Zeng, Wen; Hu, Xueyu; Liu, Zhongyang; Huang, Jinghui; Luo, Zhuojing

    2013-02-01

    Electrical stimulation (ES) applied to a conductive nerve graft holds the great potential to improve nerve regeneration and functional recovery in the treatment of lengthy nerve defects. A conductive nerve graft can be obtained by a combination of conductive nerve scaffold and olfactory ensheathing cells (OECs), which are known to enhance axonal regeneration and to produce myelin after transplantation. However, when ES is applied through the conductive graft, the impact of ES on OECs has never been investigated. In this study, a biodegradable conductive composite made of conductive polypyrrole (PPy, 2.5%) and biodegradable chitosan (97.5%) was prepared in order to electrically stimulate OECs. The tolerance of OECs to ES was examined by a cell apoptosis assay. The growth of the cells was characterized using DAPI staining and a CCK-8 assay. The mRNA and protein levels of brain-derived neurotrophic factor (BDNF), nerve growth factor (NGF), neural cell adhesion molecule (N-CAM), vascular endothelial growth factor (VEGF) and neurite outgrowth inhibitor-A (NOGO-A) in OECs were assayed by RT-PCR and Western blotting, and the amount of BDNF, NGF, N-CAM, VEGF and NOGO-A secreted was determined by an ELISA assay. The results showed that the PPy/chitosan membranes supported cell adhesion, spreading, and proliferation with or without ES. Interestingly, ES applied through the PPy/chitosan composite dramatically enhanced the expression and secretion of BDNF, NGF, N-CAM and VEGF, but decreased the expression and secretion of NOGO-A when compared with control cells without ES. These findings highlight the possibility of enhancing nerve regeneration in conductive scaffolds through ES increased neurotrophin secretion in OECs.

  1. Attenuation of transplant arteriosclerosis by oral feeding of major histocompatibility complex encoding chitosan-DNA nanoparticles.

    PubMed

    Goldmann, Katja; Hoffmann, Julia; Eckl, Sebastian; Spriewald, Bernd M; Ensminger, Stephan M

    2013-01-01

    One promising approach for the induction of transplant tolerance is the pre-treatment of transplant recipients with donor MHC-alloantigen. Our study focuses on the oral delivery of MHC-antigen encoding genes via chitosan-DNA nanoparticles to modulate the alloimmune response in order to reduce the development of transplant arteriosclerosis, the hallmark feature of chronic rejection after heart transplantation. Therefore, we performed fully allogeneic mouse abdominal aortic transplants using C57BL/6 (H2(b)) mice as donors and CBA.J (H2(k)) mice as recipients. Aortic grafts were analyzed by histology and morphometry on day 30 after transplantation, levels of circulating alloantibodies were detected by FACS analysis. Pre-treatment of recipient mice with chitosan-DNA nanoparticles encoding for K(b), one of the MHC-I molecules of the donor, resulted in a significant reduction of intimal proliferation compared to untreated controls. When Ovalbumin was fed instead of K(b) encoding nanoparticles (K(b)-NP) or Balb/c (H2(d)) grafts were used instead of C57BL/6 (H2(b)) grafts as antigen controls, both groups showed no reduction of intimal thickness indicating an antigen-specific mechanism. In addition, analysis of peripheral blood of the transplanted mice showed significant suppression of alloantibody formation in the K(b)-NP fed group compared to all other allogeneic transplanted groups suggesting modulation of the humoral immune response. These results demonstrate the potential of chitosan-DNA nanoparticles to induce K(b)-specific tolerance and to reduce the development of transplant arteriosclerosis.

  2. Alveolar bone grafting.

    PubMed

    Semb, Gunvor

    2012-01-01

    In the 1970s, Boyne and Sands published reports on a new technique for alveolar bone grafting. They recommended that only cancellous bone be used and that the procedure be undertaken in the mixed dentition prior to canine eruption. Alveolar bone grafting prior to canine eruption soon became a routine part of the protocol for 90% of European and North American cleft teams. Several uncertainties remain however, such as the specifics of the surgical and orthodontic procedures, type of bone and donor site, and the best way to manage the space in the dental arch. Probably the commonest timing of the bone graft falls between 8 and 11 years, however there has been a trend in some centres to graft earlier in the hope of better outcome for the unerupted incisors. The influence on maxillary growth of earlier grafting has not been ascertained. A wide range of donor sites has been use but iliac crest remains the most popular. Many teams perform orthodontics prior to grafting to correct severe segment displacement or align incisors to improve surgical access. Following grafting, absence of the lateral incisor may be managed with orthodontic space closure, placement of an implant or bridgework. The introduction of alveolar bone grafting probably represents one of the most significant clinical innovations in cleft care. Hopefully, advances in tissue engineering will replace the need for transplantation of autogenous bone, or will provide an in-situ biological solution to the generation of a continuous bone fill across the alveolar cleft. Copyright © 2012 S. Karger AG, Basel.

  3. Antibacterial and antioxidative activity of O-amine functionalized chitosan.

    PubMed

    Tamer, Tamer M; Hassan, Mohamed A; Omer, Ahmed M; Valachová, Katarína; Eldin, Mohamed S Mohy; Collins, Maurice N; Šoltés, Ladislav

    2017-08-01

    Cinnamaldehyde was immobilized to O-amine functionalized chitosan via a coupling reaction. Fourier transform infrared spectroscopy confirmed N-cinnamyl substitution. Wetting analyses demonstrate more hydrophobicity in the N-cinnamyl substituted O-amine functionalized chitosan compared to chitosan or unsubstituted O-amine functionalized chitosan. Thermal gravimetric analysis and differential scanning calorimetry demonstrates that the prepared N-cinnamyl substituted O-amine functionalized chitosan exhibits higher thermostability than unmodified chitosan at temperatures in which polysaccharides are commonly stored and utilised. The N-cinnamyl substituted O-amine functionalized chitosan, against four different bacteria strains [two gram-positive (Staphylococcus aureus and Bacillus cereus) and two gram-negative (Escherichia coli and Pseudomonas aeruginosa)], displays promotion of inhibition activity against these bacterial strains. Finally, the antioxidative activity of the N-cinnamyl substituted O-amine functionalized chitosan was compared with those activities of chitosan and O-amine functionalized chitosan. This was evaluated by uninhibited and inhibited hyaluronan degradation and ABTS assay. The N-cinnamyl substituted O-amine functionalized chitosan shows a lower activity towards donating a hydrogen radical compared to chitosan or O-amine functionalized chitosan. On the other hand, the N-cinnamyl substituted O-amine functionalized chitosan exhibited a higher ability to scavenge the ABTS(+) cation radical compared to chitosan and O-amine functionalized chitosan. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. Preparation and characterisation of zein and chitosan edible film

    USDA-ARS?s Scientific Manuscript database

    The aim of this work was to develop zein/chitosan blends and study the heat effect on chitosan in the film-making process. The zein and chitosan solutions were prepared separately; two different chitosan solutions were produced, one heated at 80 ºC for 1 h, and another just stirred for 1 h and unhea...

  5. Ovarian and Uterine Grafts

    PubMed Central

    Cheval, Max

    1934-01-01

    Recent experience has convinced the author of the value of ovarian grafting. He gives the histories of a number of women upon whom he made implants of their own ovarian tissue in the course of operations for double oöphorectomy. The subsequent state of these patients is contrasted with that of women after castration without grafting. When the uterus was left in position menstruation was re-established in over 80% of the grafted cases. The author and his co-workers maintain that the vitality of autogenous grafts of ovarian substance is enhanced by hormones produced by the uterine mucosa. He therefore advocates that grafts of uterus be made in conjunction with ovarian implants whenever possible. Experiments carried out on animals have proved the correctness of this opinion. The results of a series of cases of combined ovarian and uterine graftings are recorded, and the technique of uterine mucosa implants is described. ImagesFig. 10Fig. 11Fig. 1Fig. 2Fig. 3Fig. 4Fig. 8Fig. 9Fig. 10Fig. 5Fig. 6 PMID:19989930

  6. Biomechanical comparison of anatomic trajectory pedicle screw versus injectable calcium sulfate graft-augmented pedicle screw for salvage in cadaveric thoracic bone.

    PubMed

    Derincek, Alihan; Wu, Chunhui; Mehbod, Amir; Transfeldt, Ensor E

    2006-06-01

    Many salvage options for failed thoracic pedicle screws exist including the use of a different trajectory or the augmentation of the screw with polymethylmethacrylate cement. Although polymethylmethacrylate immediately increases the construct stiffness and the pull-out strength, it may cause bone necrosis, toxin relaxation, and/or neural injury. On the other hand, calcium sulfate bone grafts have a high potential for biologic incorporation and no thermal damage effect. In the current study, polyaxial pedicle screws were first inserted with a straightforward approach on both sides in 17 fresh human cadaveric thoracic vertebrae. The maximal insertion torque for each screw was measured and then the pull-out strengths were recorded. Afterward, these pedicle screws were randomly assigned to be replaced either by graft augmentation or by anatomic trajectory technique for salvage. The graft-augmented screws were placed using the previous holes. The maximum insertional torque for each anatomic trajectory screw was measured. Finally, the pull-out strengths of the revision screws were recorded. The mean maximum insertional torque decreased with the anatomic trajectory salvage technique when compared with the straightforward approach, 0.23 versus 0.38 Nm, respectively (P=0.003). The anatomic trajectory revision resulted in decreased pull-out strength when compared with the pull-out strength of the straightforward technique, 297 versus 469 N, respectively (P=0.003). The calcium sulfate graft augmentation increased the pull-out strength when compared with the pull-out strength of the straightforward technique, 680 versus 477 N, respectively (P=0.017). The mean pull-out strength ratio of revised screw to original was 0.71 for anatomic trajectory and 1.8 for graft-augmented screws, a statistically significant difference (P=0.002).

  7. In-vitro hemocompatibility evaluation of a thermoplastic polyurethane membrane with surface-immobilized water-soluble chitosan and heparin.

    PubMed

    Lin, Wen-Ching; Tseng, Chien-Hao; Yang, Ming-Chien

    2005-10-20

    The surface of a thermoplastic polyurethane (TPU) membrane was treated with low temperature plasma (LTP) and was then grafted with poly(acrylic acid) (PAA), followed by the grafting of water-soluble chitosan (WSC) and heparin (HEP). The surface was characterized with static contact-angle and X-ray photoelectron spectroscopy (XPS). The results showed that the surface densities of peroxides and PAA reached a maximum when treated with LTP for 90 s. A higher pH of the reacting solution led to higher graft densities of WSC and HEP. After WSC and HEP grafting, the hydrophilicity of the TPU membrane was increased. The adsorption of proteins on HEP-grafted TPU membranes was effectively curtailed. In addition, HEP grafting also reduced platelet adhesion, elevated thrombin inactivation, and prolonged the blood coagulation time. According to the L929 fibroblast cell growth inhibition index, the HEP-grafted TPU membranes exhibited non-cytotoxicity. Overall results demonstrated that the HEP immobilization could not only improve the hydrophilicity but also the hemocompatibility of the TPU membrane, while maintaining the ascendant biocompatibility.

  8. Fragmentation of Chitosan by Acids

    PubMed Central

    Arul, Joseph; Charlet, Gérard

    2013-01-01

    Fragmentation of chitosan in aqueous solution by hydrochloric acid was investigated. The kinetics of fragmentation, the number of chain scissions, and polydispersity of the fragments were followed by viscometry and size exclusion chromatography. The chemical structure and the degree of N-acetylation (DA) of the original chitosan and its fragments were examined by 1H NMR spectroscopy and elemental analysis. The kinetic data indicates that the reaction was of first order. The results of polydispersity and the DA suggest that the selected experimental conditions (temperature and concentration of acid) were appropriate to obtain the fragments having the polydispersity and the DA similar to or slightly different from those of the original one. A procedure to estimate molecular weight of fragments as well as the number of chain scissions of the fragments under the experimental conditions was also proposed. PMID:24302858

  9. Preparation, characterization, and potential application of chitosan, chitosan derivatives, and chitosan metal nanoparticles in pharmaceutical drug delivery

    PubMed Central

    Ahmed, Tarek A; Aljaeid, Bader M

    2016-01-01

    Naturally occurring polymers, particularly of the polysaccharide type, have been used pharmaceutically for the delivery of a wide variety of therapeutic agents. Chitosan, the second abundant naturally occurring polysaccharide next to cellulose, is a biocompatible and biodegradable mucoadhesive polymer that has been extensively used in the preparation of micro-as well as nanoparticles. The prepared particles have been exploited as a potential carrier for different therapeutic agents such as peptides, proteins, vaccines, DNA, and drugs for parenteral and nonparenteral administration. Therapeutic agent-loaded chitosan micro- or nanoparticles were found to be more stable, permeable, and bioactive. In this review, we are highlighting the different methods of preparation and characterization of chitosan micro- and nanoparticles, while reviewing the pharmaceutical applications of these particles in drug delivery. Moreover, the roles of chitosan derivatives and chitosan metal nanoparticles in drug delivery have been illustrated. PMID:26869768

  10. Topical formulations and wound healing applications of chitosan.

    PubMed

    Ueno, H; Mori, T; Fujinaga, T

    2001-11-05

    Chitosan is being used as a wound-healing accelerator in veterinary medicine. To our knowledge, chitosan enhances the functions of inflammatory cells such as polymorphonuclear leukocytes (PMN) (phagocytosis, production of osteopontin and leukotriene B4), macrophages (phagocytosis, production of interleukin (IL)-1, transforming growth factor beta 1 and platelet derived growth factor), and fibroblasts (production of IL-8). As a result, chitosan promotes granulation and organization, therefore chitosan is beneficial for the large open wounds of animals. However, there are some reported complications of chitosan application. Firstly, chitosan causes lethal pneumonia in dogs which are given a high dose of chitosan. In spite of application of chitosan to various species, this finding is observed only in dogs. Secondly, intratumor injection of chitosan on mice bearing tumor increases the rate of metastasis and tumor growth. Therefore, it is important to consider these effects of chitosan, prior to drug delivery.

  11. Characterization of Chitosan Nanofiber Sheets for Antifungal Application

    PubMed Central

    Egusa, Mayumi; Iwamoto, Ryo; Izawa, Hironori; Morimoto, Minoru; Saimoto, Hiroyuki; Kaminaka, Hironori; Ifuku, Shinsuke

    2015-01-01

    Chitosan produced by the deacetylation of chitin is a cationic polymer with antimicrobial properties. In this study, we demonstrate the improvement of chitosan properties by nanofibrillation. Nanofiber sheets were prepared from nanofibrillated chitosan under neutral conditions. The Young’s modulus and tensile strength of the chitosan NF sheets were higher than those of the chitosan sheets prepared from dissolving chitosan in acetic acid. The chitosan NF sheets showed strong mycelial growth inhibition against dermatophytes Microsporum and Trichophyton. Moreover, the chitosan NF sheets exhibited resistance to degradation by the fungi, suggesting potentials long-lasting usage. In addition, surface-deacetylated chitin nanofiber (SDCNF) sheets were prepared. The SDCNF sheet had a high Young’s modulus and tensile strength and showed antifungal activity to dermatophytes. These data indicate that nanofibrillation improved the properties of chitosan. Thus, chitosan NF and SDCNF sheets are useful candidates for antimicrobial materials. PMID:26540046

  12. Enzyme-sensing chitosan hydrogels.

    PubMed

    Sadat Ebrahimi, Mir Morteza; Schönherr, Holger

    2014-07-08

    We report on a chitosan hydrogel-based platform for the detection of enzymes, which is compatible with the implementation in infection-sensing wound dressings. Thin films of the established wound dressing biopolymer chitosan were functionalized with a fluorogenic substrate, which is released upon enzymatic degradation, resulting in a pronounced increase in fluorescence emission intensity. In this first model study, the fluorogenic substrate alanyl-alanyl-phenylalanine-7-amido-4-methylcoumarin (AAP-AMC) was covalently conjugated via amide bond formation to chitosan and was shown to facilitate the detection of the serine protease α-chymotrypsin. Systematic investigations established the dependence of hydrogel thickness and substrate loading on the hydrogel preparation conditions, as well as the dependence of the rate of the reaction on the initial enzyme concentration and the loading of AAP-AMC in the hydrogel. The initial release rate of the fluorophore 7-AMC was found to be linear with enzyme concentration and substrate loading and was independent of hydrogel thickness. Under optimized conditions the hydrogel reports the presence of α-chymotrypsin in <5 min with a limit of detection of ≤10 nM. This generic approach, which can be adapted to detect different kinds of enzymes by using appropriate fluorogenic or chromogenic substrates, is highly interesting for targeting the detection of specific pathogenic bacteria, e.g., in wound dressings.

  13. Characterization of calcium carbonate/chitosan composites

    SciTech Connect

    Gonsalves, K.E.; Zhang, S.

    1995-12-31

    The crystal growth of calcium carbonate on a chitosan substrate was achieved using a supersaturated calcium carbonate solution, by using various additives, polyacrylic acid (PAA). Polyacrylic acid modified the chitosan-film surface and promoted the nucleation of calcium carbonate crystals.

  14. Synthesis and characterization of chitosan alkyl urea.

    PubMed

    Wang, Jing; Jiang, Ji-Zhou; Chen, Wei; Bai, Zheng-Wu

    2016-07-10

    Chitosan is a versatile material employed for various purposes in many fields including the development of chiral stationary phases for enantioseparation. Chitosan alkyl urea is a kind of intermediate used to prepare enantioseparation materials. In order to synthesize the intermediates, in the present work, a new way to prepare chitosan alkyl urea has been established: chitosan was first reacted with methyl chloroformate yielding N-methoxyformylated chitosan, which was then converted to chitosan alkyl urea through amine-ester exchange reaction. With a large excess of methyl chloroformate and primary amine of low stereohindrance, the amino group in chitosan could be almost completely converted to ureido group. The as-prepared chitosan alkyl urea derivatives were characterized by IR, (1)H NMR, (13)C NMR,(1)H-(1)H COSY and (1)H-(13)C HSQC NMR spectra. The chemical shifts of hydrogen and carbon atoms of glucose unit were assigned. It was found that the degree of substitution was obviously lower if cyclopropyl amine, aniline, tert-butyl amine and diethyl amine were used as reactants for the amine-ester exchange reaction. The reason was explained with the aid of theoretical calculations. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. Multifaceted Applications of Chitosan in Cancer Drug Delivery and Therapy.

    PubMed

    Babu, Anish; Ramesh, Rajagopal

    2017-03-27

    Chitosan is a versatile polysaccharide of biological origin. Due to the biocompatible and biodegradable nature of chitosan, it is intensively utilized in biomedical applications in scaffold engineering as an absorption enhancer, and for bioactive and controlled drug release. In cancer therapy, chitosan has multifaceted applications, such as assisting in gene delivery and chemotherapeutic delivery, and as an immunoadjuvant for vaccines. The present review highlights the recent applications of chitosan and chitosan derivatives in cancer therapy.

  16. Hydrogels made from chitosan and silver nitrate.

    PubMed

    Kozicki, Marek; Kołodziejczyk, Marek; Szynkowska, Małgorzata; Pawlaczyk, Aleksandra; Leśniewska, Ewa; Matusiak, Aleksandra; Adamus, Agnieszka; Karolczak, Aleksandra

    2016-04-20

    This work describes a gelation of chitosan solution with silver nitrate. Above the critical concentration of chitosan (c*), continuous hydrogels of chitosan-silver can be formed. At lower concentrations, the formation of nano- and micro-hydrogels is discussed. The sol-gel analysis was performed to characterise the hydrogels' swelling properties. Moreover, the following were employed: (i) mechanical testing of hydrogels, (ii) inductively coupled plasma-optical emission spectroscopy (ICP-OES) for the measurement of silver concentration, (iii) scanning electron microscopy (SEM) to examine the morphology of products obtained, and (iv) dynamic light scattering (DLS) and UV-vis spectrophotometry to examine products formed at low concentration of chitosan (cchitosan used that showed no such activity.

  17. Chitosan nanofiber production from Drosophila by electrospinning.

    PubMed

    Kaya, Murat; Akyuz, Bahar; Bulut, Esra; Sargin, Idris; Eroglu, Fatma; Tan, Gamze

    2016-11-01

    Drosophila melanogaster is one of the important test organisms in genetics thanks to its fast growth rate in a culture. This study demonstrates that the fly D. melanogaster can also be exploited as a source for nanofiber production in biotechnical applications. First, its chitin content was determined (7.85%) and then high molecular weight chitosan (141.4kDa) was synthesized through deacetylation of chitin isolates. Chitosan nanofibers with the diameter of 40.0073±12.347nm were produced by electrospinning of Drosophila chitosan. The physicochemical properties of obtained chitin and chitosan from D. melanogaster were determined by Thermogravimetric Analysis (TGA), Scanning Electron Microscopy (SEM) and Fourier Transform Infrared Spectroscopy (FT-IR). The study demonstrated that the fly D. melanogaster can be utilized for production of chitosan nanofiber concerning its cultivability and low-cost culture requirements.

  18. Chitosan magnetic nanoparticles for drug delivery systems.

    PubMed

    Assa, Farnaz; Jafarizadeh-Malmiri, Hoda; Ajamein, Hossein; Vaghari, Hamideh; Anarjan, Navideh; Ahmadi, Omid; Berenjian, Aydin

    2017-06-01

    The potential of magnetic nanoparticles (MNPs) in drug delivery systems (DDSs) is mainly related to its magnetic core and surface coating. These coatings can eliminate or minimize their aggregation under physiological conditions. Also, they can provide functional groups for bioconjugation to anticancer drugs and/or targeted ligands. Chitosan, as a derivative of chitin, is an attractive natural biopolymer from renewable resources with the presence of reactive amino and hydroxyl functional groups in its structure. Chitosan nanoparticles (NPs), due to their huge surface to volume ratio as compared to the chitosan in its bulk form, have outstanding physico-chemical, antimicrobial and biological properties. These unique properties make chitosan NPs a promising biopolymer for the application of DDSs. In this review, the current state and challenges for the application magnetic chitosan NPs in drug delivery systems were investigated. The present review also revisits the limitations and commercial impediments to provide insight for future works.

  19. Functional properties of chitosan-based films.

    PubMed

    Leceta, I; Guerrero, P; de la Caba, K

    2013-03-01

    Chitosan-based films plasticized with glycerol were prepared by casting with the aim to obtain environmentally friendly materials for packaging applications. Different contents of glycerol were incorporated into chitosan solutions to improve mechanical properties and all films obtained were flexible and transparent. It was observed that the transparency and good behaviour of the films against UV radiation were not affected by chitosan molecular weight or glycerol content. Moreover, chitosan-based films exhibited excellent barrier properties against water vapour and oxygen, even with the addition of glycerol. The effect of the plasticizer on the properties has been explained using Fourier transform infrared (FTIR) spectroscopic analysis. The changes observed in the intensity of the bands showed that glycerol interacts with chitosan, which could be confirmed by total soluble matter (TSM). Copyright © 2012 Elsevier Ltd. All rights reserved.

  20. Biodegradable chitosan nanogels crosslinked with genipin.

    PubMed

    Arteche Pujana, Maite; Pérez-Álvarez, Leyre; Cesteros Iturbe, Luis Carlos; Katime, Issa

    2013-05-15

    Chitosan nanoparticles crosslinked with genipin were prepared by reverse microemulsion that allowed to obtain highly monodisperse (3-20 nm by TEM) nanogels. The incorporation of genipin into chitosan was confirmed and quantitatively evaluated by UV-vis and (1)H NMR. Loosely crosslinked chitosan networks showed higher water solubility at neutral pHs than pure chitosan. The hydrodynamic diameter of the genipin-chitosan nanogels ranged from 270 to 390 nm and no remarkable differences were found when the crosslinking degree was varied. The hydrodynamic diameters of the nanoparticles increased slightly at acidic pH and the protonation of ionizable amino groups with the pH was confirmed by the zeta potential measurements. The biocompatible and biodegradable nature, as well as the colloidal and monodisperse particle size of the prepared nanogels, make them attractive candidates for a large variety of biomedical applications. Copyright © 2013 Elsevier Ltd. All rights reserved.

  1. Transfection efficiency of chitosan and thiolated chitosan in retinal pigment epithelium cells: A comparative study

    PubMed Central

    Oliveira, Ana V.; Silva, Andreia P.; Bitoque, Diogo B.; Silva, Gabriela A.; Rosa da Costa, Ana M.

    2013-01-01

    OBJECTIVE: Gene therapy relies on efficient vector for a therapeutic effect. Efficient non-viral vectors are sought as an alternative to viral vectors. Chitosan, a cationic polymer, has been studied for its gene delivery potential. In this work, disulfide bond containing groups were covalently added to chitosan to improve the transfection efficiency. These bonds can be cleaved by cytoplasmic glutathione, thus, releasing the DNA load more efficiently. MATERIALS AND METHODS: Chitosan and thiolated chitosan nanoparticles (NPs) were prepared in order to obtain a NH3+:PO4− ratio of 5:1 and characterized for plasmid DNA complexation and release efficiency. Cytotoxicity and gene delivery studies were carried out on retinal pigment epithelial cells. RESULTS: In this work, we show that chitosan was effectively modified to incorporate a disulfide bond. The transfection efficiency of chitosan and thiolated chitosan varied according to the cell line used, however, thiolation did not seem to significantly improve transfection efficiency. CONCLUSION: The apparent lack of improvement in transfection efficiency of the thiolated chitosan NPs is most likely due to its size increase and charge inversion relatively to chitosan. Therefore, for retinal cells, thiolated chitosan does not seem to constitute an efficient strategy for gene delivery. PMID:23833516

  2. Enhancing effects of chitosan and chitosan hydrochloride on intestinal absorption of berberine in rats.

    PubMed

    Chen, Wei; Fan, Dongjiao; Meng, Lingkuo; Miao, Yuqiang; Yang, Shenshen; Weng, Yan; He, Haibing; Tang, Xing

    2012-01-01

    Berberine chloride (BBR) is a plant alkaloid that has been used for centuries for treatment of inflammation, dysentery, and liver diseases. It is poorly absorbed from the gastrointestinal (GI) tract and its various clinical uses are limited because of its poor bioavailability. The object of the present study was to investigate the absorption enhancing effect of chitosan on BBR. Mixtures