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Sample records for methacrylic acid gelatin

  1. Crosslinked Graft Copolymer of Methacrylic Acid and Gelatin as a Novel Hydrogel with pH-Responsiveness Properties

    PubMed Central

    Sadeghi, Mohammad; Heidari, Behrouz

    2011-01-01

    In this paper, a novel gelatin-based hydrogel was synthesized through crosslinking graft copolymerization of methacrylic acid (MAA) onto gelatin, using ammonium persulfate (APS) as a free radical initiator in the presence of methylenebisacrylamide (MBA) as a crosslinker. A proposed mechanism for hydrogel formation was suggested and the structure of the product was established using FTIR spectroscopy and gravimetric analysis of the products. Moreover, morphology of the samples was examined by scanning electron microscopy (SEM) and thermogravimetric analysis (TGA/DTG). The effect of reaction variables such as concentration of APS and MBA were systematically optimized to achieve a hydrogel with swelling capacity as high as possible. The gelatin-g-PMAA hydrogel exhibited a pH-responsiveness character so that a swelling-deswelling pulsatile behavior was recorded at pHs 2 and 8. This on-off switching behavior makes the hydrogel as a good candidate for controlled delivery of bioactive agents. PMID:28880004

  2. Gelatin Methacrylate Microspheres for Growth Factor Controlled Release

    PubMed Central

    Nguyen, Anh H.; McKinney, Jay; Miller, Tobias; Bongiorno, Tom; McDevitt, Todd C.

    2014-01-01

    Gelatin has been commonly used as a delivery vehicle for various biomolecules for tissue engineering and regenerative medicine applications due to its simple fabrication methods, inherent electrostatic binding properties, and proteolytic degradability. Compared to traditional chemical cross-linking methods, such as the use of glutaraldehyde (GA), methacrylate modification of gelatin offers an alternative method to better control the extent of hydrogel cross-linking. Here we examined the physical properties and growth factor delivery of gelatin methacrylate (GMA) microparticles formulated with a wide range of different cross-linking densities (15–90%). Less methacrylated MPs had decreased elastic moduli and larger mesh sizes compared to GA MPs, with increasing methacrylation correlating to greater moduli and smaller mesh sizes. As expected, an inverse correlation between microparticle cross-linking density and degradation was observed, with the lowest cross-linked GMA MPs degrading at the fastest rate, comparable to GA MPs. Interestingly, GMA MPs at lower cross-linking densities could be loaded with up to a 10-fold higher relative amount of growth factor over conventional GA cross-linked MPs, despite an order of magnitude greater gelatin content of GA MPs. Moreover, a reduced GMA cross-linking density resulted in more complete release of bone morphogenic protein 4 (BMP4) and basic fibroblast growth factor (bFGF) and accelerated release rate with collagenase treatment. These studies demonstrate that GMA MPs provide a more flexible platform for growth factor delivery by enhancing the relative binding capacity and permitting proteolytic degradation tunability, thereby offering a more potent controlled release system for growth factor delivery. PMID:25463489

  3. Fabrication of conductive gelatin methacrylate-polyaniline hydrogels.

    PubMed

    Wu, Yibo; Chen, Yong X; Yan, Jiahan; Quinn, David; Dong, Ping; Sawyer, Stephen W; Soman, Pranav

    2016-03-01

    Hydrogels with inherently conductive properties have been recently developed for tissue engineering applications, to serve as bioactive scaffolds to electrically stimulate cells and modulate their function. In this work, we have used interfacial polymerization of aniline monomers within gelatin methacrylate (GelMA) to develop a conductive hybrid composite. We demonstrate that as compared to pure GelMA, GelMA-polyaniline (GelMA-Pani) composite has similar swelling properties and compressive modulus, comparable cell adhesion and spreading responses, and superior electrical properties. Additionally, we demonstrate that GelMA-Pani composite can be printed in complex user-defined geometries using digital projection stereolithography, and will be useful in developing next-generation bioelectrical interfaces. We report the fabrication of a conductive hydrogel using naturally-derived gelatin methyacrylate (GelMA) and inherently conductive polyaniline (Pani). This work is significant, as GelMA-Pani composite has superior electrical properties as compared to pure Gelma, all the while maintaining biomimetic physical and biocompatible properties. Moreover, the ability to fabricate conductive-GelMA in complex user-defined micro-geometries, address the significant processing challenges associated with all inherently conductive polymers including Pani. The methodology described in this work can be extended to several conductive polymers and hydrogels, to develop new biocompatible electrically active interfaces. Copyright © 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  4. Directed Endothelial Cell Morphogenesis in Micropatterned Gelatin Methacrylate Hydrogels

    PubMed Central

    Nikkhah, Mehdi; Eshak, Nouran; Zorlutuna, Pinar; Annabi, Nasim; Castello, Marco; Kim, Keekyoung; Dolatshahi-Pirouz, Alireza; Edalat, Faramarz; Bae, Hojae; Yang, Yunzhi; Khademhosseini, Ali

    2013-01-01

    Engineering of organized vasculature is a crucial step in the development of functional and clinically relevant tissue constructs. A number of previous techniques have been proposed to spatially regulate the distribution of angiogenic biomolecules and vascular cells within biomaterial matrices to promote vascularization. Most of these approaches have been limited to two-dimensional (2D) micropatterned features or have resulted in formation of random vasculature within three-dimensional (3D) microenvironments. In this study, we investigate 3D endothelial cord formation within micropatterned gelatin methacrylate (GelMA) hydrogels with varying geometrical features (50–150 µm height). We demonstrated the significance dependence of endothelial cells proliferation, alignment and cord formation on geometrical dimensions of the patterned features. The cells were able to align and organize within the micropatterned constructs and assemble to form cord structures with organized actin fibers and circular/elliptical cross-sections. The inner layer of the cord structure was filled with gel showing that the micropatterned hydrogel constructs guided the assembly of endothelial cells into cord structures. Notably, the endothelial cords were retained within the hydrogel microconstructs for all geometries after two weeks of culture; however, only the 100 µm-high constructs provided the optimal microenvironment for the formation of circular and stable cord structures. Our findings suggest that endothelial cord formation is a preceding step to tubulogenesis and the proposed system can be used to develop organized vasculature for engineered tissue constructs. PMID:23018132

  5. Synthesis and Characterization of Hybrid Hyaluronic Acid-Gelatin Hydrogels

    PubMed Central

    Camci-Unal, Gulden; Cuttica, Davide; Annabi, Nasim; Demarchi, Danilo; Khademhosseini, Ali

    2013-01-01

    Biomimetic hybrid hydrogels have generated broad interest in tissue engineering and regenerative medicine. Hyaluronic acid (HA) and gelatin (hydrolyzed collagen) are naturally derived polymers and biodegradable under physiological conditions. Moreover, collagen and HA are major components of the extracellular matrix (ECM) in most of the tissues (e.g. cardiovascular, cartilage, neural). When used as a hybrid material, HA-gelatin hydrogels may enable mimicking the ECM of native tissues. Although HA-gelatin hybrid hydrogels are promising biomimetic substrates, their material properties have not been thoroughly characterized in the literature. Herein, we generated hybrid hydrogels with tunable physical and biological properties by using different concentrations of HA and gelatin. The physical properties of the fabricated hydrogels including swelling ratio, degradation, and mechanical properties were investigated. In addition, in vitro cellular responses in both two and three dimensional (2D and 3D) culture conditions were assessed. It was found that the addition of gelatin methacrylate (GelMA) into HA methacrylate (HAMA) promoted cell spreading in the hybrid hydogels. Moreover, the hybrid hydrogels showed significantly improved mechanical properties compared to their single component analogs. The HAMA-GelMA hydrogels exhibited remarkable tunability behavior and may be useful for cardiovascular tissue engineering applications. PMID:23419055

  6. Low-cost fabrication of poly(methyl methacrylate) microchips using disposable gelatin gel templates.

    PubMed

    Chen, Zhi; Yu, Zhengyin; Chen, Gang

    2010-06-15

    A simple method based on disposable gelatin gel templates has been developed for the low-cost fabrication of poly(methyl methacrylate) (PMMA) microfluidic chips. Gelatin was dissolved in glycerol aqueous solution under heat to prepare a thermally reversible impression material. The molten gel was then sandwiched between a glass plate and a SU-8 template bearing negative relief of microstructure. After cooling, the negative SU-8 template could be easily separated from the solidified gelatin gel and a layer of gelatin template bearing positive relief of the microstructure was left on the glass plate. Subsequently, prepolymerized methyl methacrylate molding solution containing a UV-initiator was sandwiched between the gel template and a PMMA plate and was allowed to polymerize under UV light to fabricate PMMA channel plate at room temperature. Complete microchips could be obtained by bonding the channel plates with covers using plasticizer-assisted thermal bonding at 90 degrees C. Gelatin gel template can be mass-produced and will find application in the mass production of PMMA microchips at low cost. The prepared microfluidic microchips have been successfully employed in the capillary electrophoresis analysis of several ions in connection with contactless conductivity detection.

  7. 21 CFR 172.775 - Methacrylic acid-divinylbenzene copolymer.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Methacrylic acid-divinylbenzene copolymer. 172.775... Additives § 172.775 Methacrylic acid-divinylbenzene copolymer. Methacrylic acid-divinylbenzene copolymer may... produced by the polymerization of methacrylic acid and divinylbenzene. The divinylbenzene functions as a...

  8. Engineered Contractile Skeletal Muscle Tissue on a Microgrooved Methacrylated Gelatin Substrate

    PubMed Central

    Hosseini, Vahid; Ahadian, Samad; Ostrovidov, Serge; Camci-Unal, Gulden; Chen, Song; Kaji, Hirokazu; Ramalingam, Murugan

    2012-01-01

    To engineer tissue-like structures, cells must organize themselves into three-dimensional (3D) networks that mimic the native tissue microarchitecture. Microfabricated hydrogel substrates provide a potentially useful platform for directing cells into biomimetic tissue architecture in vitro. Here, we present microgrooved methacrylated gelatin hydrogels as a suitable platform to build muscle-like fibrous structures in a facile and highly reproducible fashion. Microgrooved hydrogel substrates with two different ridge sizes (50 and 100 μm) were fabricated to assess the effect of the distance between engineered myofibers on the orientation of the bridging C2C12 myoblasts and the formation of the resulting multinucleated myotubes. It was shown that although the ridge size did not significantly affect the C2C12 myoblast alignment, the wider-ridged micropatterned hydrogels generated more myotubes that were not aligned to the groove direction as compared to those on the smaller-ridge micropatterns. We also demonstrated that electrical stimulation improved the myoblast alignment and increased the diameter of the resulting myotubes. By using the microstructured methacrylated gelatin substrates, we built free-standing 3D muscle sheets, which contracted when electrically stimulated. Given their robust contractility and biomimetic microarchitecture, engineered tissues may find use in tissue engineering, biological studies, high-throughput drug screening, and biorobotics. PMID:22963391

  9. Transdermal regulation of vascular network bioengineering using a photopolymerizable methacrylated gelatin hydrogel

    PubMed Central

    Lin, Ruei-Zeng; Chen, Ying-Chieh; Moreno-Luna, Rafael; Khademhosseini, Ali; Melero-Martin, Juan M.

    2013-01-01

    The search for hydrogel materials compatible with vascular morphogenesis is an active area of investigation in tissue engineering. One candidate material is methacrylated gelatin (GelMA), a UV-photocrosslinkable hydrogel that is synthesized by adding methacrylate groups to the amine-containing side-groups of gelatin. GelMA hydrogels containing human endothelial colony-forming cells (ECFCs) and mesenchymal stem cells (MSCs) can be photopolymerized ex vivo and then surgically transplanted in vivo as a means to generate vascular networks. However, the full clinical potential of GelMA will be best captured by enabling minimally invasive implantation and in situ polymerization. In this study, we demonstrated the feasibility of bioengineering human vascular networks inside GelMA constructs that were first subcutaneously injected into immunodeficient mice while in liquid form, and then rapidly crosslinked via transdermal exposure to UV light. These bioengineered vascular networks developed within 7 days, formed functional anastomoses with the host vasculature, and were uniformly distributed throughout the constructs. Most notably, we demonstrated that the vascularization process can be directly modulated by adjusting the initial exposure time to UV light (15–45 s range), with constructs displaying progressively less vascular density and smaller average lumen size as the degree of GelMA crosslinking was increased. Our studies support the use of GelMA in its injectable form, followed by in situ transdermal photopolymerization, as a preferable means to deliver cells in applications that require the formation of vascular networks in vivo. PMID:23773819

  10. Bio-based production of methacrylic acid

    USDA-ARS?s Scientific Manuscript database

    Methacrylic acid (MAA) is an important industrial chemical commodity, with annual production exceeding 3 million metric tons and a market value surpassing $9 billion. The primary use of MAA is the conversion to ester derivatives, which are further converted into numerous useful polymers. Despite the...

  11. 21 CFR 172.775 - Methacrylic acid-divinylbenzene copolymer.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Methacrylic acid-divinylbenzene copolymer. 172.775... HUMAN CONSUMPTION Other Specific Usage Additives § 172.775 Methacrylic acid-divinylbenzene copolymer. Methacrylic acid-divinylbenzene copolymer may be safely used in food in accordance with the following...

  12. 21 CFR 172.775 - Methacrylic acid-divinylbenzene copolymer.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Methacrylic acid-divinylbenzene copolymer. 172.775... HUMAN CONSUMPTION Other Specific Usage Additives § 172.775 Methacrylic acid-divinylbenzene copolymer. Methacrylic acid-divinylbenzene copolymer may be safely used in food in accordance with the following...

  13. 21 CFR 172.775 - Methacrylic acid-divinylbenzene copolymer.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Methacrylic acid-divinylbenzene copolymer. 172.775... HUMAN CONSUMPTION Other Specific Usage Additives § 172.775 Methacrylic acid-divinylbenzene copolymer. Methacrylic acid-divinylbenzene copolymer may be safely used in food in accordance with the following...

  14. Facile One-step Micropatterning Using Photodegradable Methacrylated Gelatin Hydrogels for Improved Cardiomyocyte Organization and Alignment

    PubMed Central

    Tsang, Kelly M.C.; Annabi, Nasim; Ercole, Francesca; Zhou, Kun; Karst, Daniel; Li, Fanyi; Haynes, John M.; Evans, Richard A.; Thissen, Helmut

    2015-01-01

    Hydrogels are often employed as temporary platforms for cell proliferation and tissue organization in vitro. Researchers have incorporated photodegradable moieties into synthetic polymeric hydrogels as a means of achieving spatiotemporal control over material properties. In this study protein-based photodegradable hydrogels composed of methacrylated gelatin (GelMA) and a crosslinker containing o-nitrobenzyl ester groups have been developed. The hydrogels are able to degrade rapidly and specifically in response to UV light and can be photopatterned to a variety of shapes and dimensions in a one-step process. Micropatterned photodegradable hydrogels are shown to improve cell distribution, alignment and beating regularity of cultured neonatal rat cardiomyocytes. Overall this work introduces a new class of photodegradable hydrogel based on natural and biofunctional polymers as cell culture substrates for improving cellular organization and function. PMID:26327819

  15. VA-086 methacrylate gelatine photopolymerizable hydrogels: A parametric study for highly biocompatible 3D cell embedding.

    PubMed

    Occhetta, Paola; Visone, Roberta; Russo, Laura; Cipolla, Laura; Moretti, Matteo; Rasponi, Marco

    2015-06-01

    The ability to replicate in vitro the native extracellular matrix (ECM) features and to control the three-dimensional (3D) cell organization plays a fundamental role in obtaining functional engineered bioconstructs. In tissue engineering (TE) applications, hydrogels have been successfully implied as biomatrices for 3D cell embedding, exhibiting high similarities to the natural ECM and holding easily tunable mechanical properties. In the present study, we characterized a promising photocrosslinking process to generate cell-laden methacrylate gelatin (GelMA) hydrogels in the presence of VA-086 photoinitiator using a ultraviolet LED source. We investigated the influence of prepolymer concentration and light irradiance on mechanical and biomimetic properties of resulting hydrogels. In details, the increasing of gelatin concentration resulted in enhanced rheological properties and shorter polymerization time. We then defined and validated a reliable photopolymerization protocol for cell embedding (1.5% VA-086, LED 2 mW/cm2) within GelMA hydrogels, which demonstrated to support bone marrow stromal cells viability when cultured up to 7 days. Moreover, we showed how different mechanical properties, derived from different crosslinking parameters, strongly influence cell behavior. In conclusion, this protocol can be considered a versatile tool to obtain biocompatible cell-laden hydrogels with properties easily adaptable for different TE applications.

  16. Biobased methacrylic acid via selective catalytic decarboxylation of itaconic acid

    USDA-ARS?s Scientific Manuscript database

    We report a bio-based route to methacrylic acid via selective decarboxylation of itaconic acid utilizing catalytic ruthenium carbonyl propionate in an aqueous solvent system. High selectivity (>90%) was achieved at low catalyst loading (0.1 mol %) with high substrate concentration (5.5 M) at low tem...

  17. Surface modification of PdlLGA microspheres with gelatine methacrylate: Evaluation of adsorption, entrapment, and oxygen plasma treatment approaches.

    PubMed

    Baki, Abdulrahman; Rahman, Cheryl V; White, Lisa J; Scurr, David J; Qutachi, Omar; Shakesheff, Kevin M

    2017-01-16

    Injectable poly (dl-lactic-co-glycolic acid) (PdlLGA) microspheres are promising candidates as biodegradable controlled release carriers for drug and cell delivery applications; however, they have limited functional groups on the surface to enable dense grafting of tissue specific biocompatible molecules. In this study we have evaluated surface adsorption, entrapment and oxygen plasma treatment as three approaches to modify the surfaces of PdlLGA microspheres with gelatine methacrylate (gel-MA) as a biocompatible and photo cross-linkable macromolecule. Time of flight secondary ion mass spectroscopy (TOF SIMS) and X-ray photoelectron spectroscopy (XPS) were used to detect and quantify gel-MA on the surfaces. Fluorescent and scanning electron microscopies (SEM) were used to image the topographical changes. Human mesenchymal stem cells (hMSCs) of immortalised cell line were cultured on the surface of gel-MA modified PdlLGA microspheres and Presto-Blue assay was used to study the effect of different surface modifications on cell proliferation. Data analysis showed that the oxygen plasma treatment approach resulted in the highest density of gel-MA deposition. This study supports oxygen plasma treatment as a facile approach to modify the surface of injectable PdlLGA microspheres with macromolecules such as gel-MA to enhance proliferation rate of injected cells and potentially enable further grafting of tissue specific molecules.

  18. Fabrication of bi-layer scaffold of keratin nanofiber and gelatin-methacrylate hydrogel: Implications for skin graft.

    PubMed

    Kim, Jong Wook; Kim, Min Jin; Ki, Chang Seok; Kim, Hyun Jeong; Park, Young Hwan

    2017-07-12

    Bi-layer scaffold composed of human hair keratin/chitosan nanofiber mat and gelatin methacrylate (GelMA) hydrogel was fabricated by using electrospinning and photopolymerization techniques. To prepare the nanofiber layer, the blend solution of human hair keratin and chitosan (mixture ratio: 5/5) was electrospun using formic acid as a solvent in the presence of poly(ethylene glycol), followed by cross-linking with glutaraldehyde. The tensile strength of the human hair keratin/chitosan nanofiber mat was much higher than that of pure human hair keratin nanofiber mat. Meanwhile, the blend nanofiber mat was relatively more compatible with HaCaT cell proliferation and keratinocyte differentiation than the pure chitosan nanofiber mat. The bi-layer scaffold was prepared by photopolymerization of GelMA under the cross-linked nanofiber mat. To evaluate the feasibility as a skin graft, human fibroblast was encapsulated in the hydrogel layer and HaCaT cells were cultured on the nanofiber layer and they were co-cultured for 10days. As a result, the encapsulated fibroblasts proliferated in the hydrogel matrix and HaCaT cells formed a cell layer on the top of scaffold, mimicking dermis and epidermis of skin tissue. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. Direct-write Bioprinting of Cell-laden Methacrylated Gelatin Hydrogels

    PubMed Central

    Bertassoni, Luiz E.; Cardoso, Juliana C.; Manoharan, Vijayan; Cristino, Ana L.; Bhise, Nupura S.; Araujo, Wesleyan A.; Zorlutuna, Pinar; Vrana, Nihal E.; Ghaemmaghami, Amir M.

    2014-01-01

    Fabrication of three dimensional (3D) organoids with controlled microarchitectures has been shown to enhance tissue functionality. Bioprinting can be used to precisely position cells and cell-laden materials to generate controlled tissue architecture. Therefore, it represents an exciting alternative for organ fabrication. Despite the rapid progress in the field, the development of printing processes that can be used to fabricate macroscale tissue constructs from ECM-derived hydrogels has remained a challenge. Here we report a strategy for bioprinting of photolabile cell-laden methacrylated gelatin (GelMA) hydrogels. We bioprinted cell-laden GelMA at concentrations ranging from 7 to 15% with varying cell densities and found a direct correlation between printability and the hydrogel mechanical properties. Furthermore, encapsulated HepG2 cells preserved cell viability for at least 8 days following the bioprinting process. In summary, this work presents a strategy for direct-write bioprinting of a cell-laden photolabile ECM-derived hydrogel, which may find widespread application for tissue engineering, organ printing and the development of 3D drug discovery platforms. PMID:24695367

  20. Photo-cross-linkable methacrylated gelatin and hydroxyapatite hybrid hydrogel for modularly engineering biomimetic osteon.

    PubMed

    Zuo, Yicong; Liu, Xiaolu; Wei, Dan; Sun, Jing; Xiao, Wenqian; Zhao, Huan; Guo, Likun; Wei, Qingrong; Fan, Hongsong; Zhang, Xingdong

    2015-05-20

    Modular tissue engineering holds great potential in regenerating natural complex tissues by engineering three-dimensional modular scaffolds with predefined geometry and biological characters. In modular tissue-like construction, a scaffold with an appropriate mechanical rigidity for assembling fabrication and high biocompatibility for cell survival is the key to the successful bioconstruction. In this work, a series of composite hydrogels (GH0, GH1, GH2, and GH3) based on a combination of methacrylated gelatin (GelMA) and hydroxyapatite (HA) was exploited to enhance hydrogel mechanical rigidity and promote cell functional expression for osteon biofabrication. These composite hydrogels presented a lower swelling ratio, higher mechanical moduli, and better biocompatibility when compared to the pure GelMA hydrogel. Furthermore, on the basis of the composite hydrogel and photolithograph technology, we successfully constructed an osteon-like concentric double-ring structure in which the inner ring encapsulating human umbilical vascular endothelial cells (HUVECs) was designed to imitate blood vessel tubule while the outer ring encapsulating human osteoblast-like cells (MG63s) acts as part of bone. During the coculture period, MG63s and HUVECs exhibited not only satisfying growth status but also the enhanced genic expression of osteogenesis-related and angiogenesis-related differentiations. These results demonstrate this GelMA-HA composite hydrogel system is promising for modular tissue engineering.

  1. Mineralized gelatin methacrylate-based matrices induce osteogenic differentiation of human induced pluripotent stem cells

    PubMed Central

    Kang, Heemin; Shih, Yu-Ru V.; Hwang, Yongsung; Wen, Cai; Rao, Vikram; Seo, Timothy; Varghese, Shyni

    2014-01-01

    Human induced pluripotent stem cells (hiPSCs) are a promising cell source with pluripotency and self-renewal properties. Design of simple and robust biomaterials with an innate ability to induce lineage-specificity of hiPSCs is desirable to realize their applications in regenerative medicine. In this study, we investigated the potential of biomaterials containing calcium phosphate minerals to induce osteogenic differentiation of hiPSCs. hiPSCs cultured using mineralized gelatin methacrylate-based matrices underwent osteogenic differentiation ex vivo, both in two- dimensional (2-D) and three-dimensional (3-D) cultures, in growth medium devoid of any osteogenic-inducing chemical components or growth factors. Our findings that osteogenic differentiation of hiPSCs can be achieved through biomaterial-based cues alone present new avenues for personalized regenerative medicine. Such biomaterials that could not only act as structural scaffolds, but could also provide tissue-specific functions such as directing stem cell differentiation commitment, have great potential in bone tissue engineering. PMID:25153779

  2. Synthesis and Characterization of Tunable Poly(Ethylene Glycol): Gelatin Methacrylate Composite Hydrogels

    PubMed Central

    Hutson, Che B.; Nichol, Jason W.; Aubin, Hug; Bae, Hojae; Yamanlar, Seda; Al-Haque, Shahed; Koshy, Sandeep T.

    2011-01-01

    Poly(ethylene glycol) (PEG) hydrogels are popular for cell culture and tissue-engineering applications because they are nontoxic and exhibit favorable hydration and nutrient transport properties. However, cells cannot adhere to, remodel, proliferate within, or degrade PEG hydrogels. Methacrylated gelatin (GelMA), derived from denatured collagen, yields an enzymatically degradable, photocrosslinkable hydrogel that cells can degrade, adhere to and spread within. To combine the desirable features of each of these materials we synthesized PEG-GelMA composite hydrogels, hypothesizing that copolymerization would enable adjustable cell binding, mechanical, and degradation properties. The addition of GelMA to PEG resulted in a composite hydrogel that exhibited tunable mechanical and biological profiles. Adding GelMA (5%–15% w/v) to PEG (5% and 10% w/v) proportionally increased fibroblast surface binding and spreading as compared to PEG hydrogels (p<0.05). Encapsulated fibroblasts were also able to form 3D cellular networks 7 days after photoencapsulation only within composite hydrogels as compared to PEG alone. Additionally, PEG-GelMA hydrogels displayed tunable enzymatic degradation and stiffness profiles. PEG-GelMA composite hydrogels show great promise as tunable, cell-responsive hydrogels for 3D cell culture and regenerative medicine applications. PMID:21306293

  3. Zwitterionic Poly(amino acid methacrylate) Brushes

    PubMed Central

    2014-01-01

    A new cysteine-based methacrylic monomer (CysMA) was conveniently synthesized via selective thia-Michael addition of a commercially available methacrylate-acrylate precursor in aqueous solution without recourse to protecting group chemistry. Poly(cysteine methacrylate) (PCysMA) brushes were grown from the surface of silicon wafers by atom-transfer radical polymerization. Brush thicknesses of ca. 27 nm were achieved within 270 min at 20 °C. Each CysMA residue comprises a primary amine and a carboxylic acid. Surface zeta potential and atomic force microscopy (AFM) studies of the pH-responsive PCysMA brushes confirm that they are highly extended either below pH 2 or above pH 9.5, since they possess either cationic or anionic character, respectively. At intermediate pH, PCysMA brushes are zwitterionic. At physiological pH, they exhibit excellent resistance to biofouling and negligible cytotoxicity. PCysMA brushes undergo photodegradation: AFM topographical imaging indicates significant mass loss from the brush layer, while XPS studies confirm that exposure to UV radiation produces surface aldehyde sites that can be subsequently derivatized with amines. UV exposure using a photomask yielded sharp, well-defined micropatterned PCysMA brushes functionalized with aldehyde groups that enable conjugation to green fluorescent protein (GFP). Nanopatterned PCysMA brushes were obtained using interference lithography, and confocal microscopy again confirmed the selective conjugation of GFP. Finally, PCysMA undergoes complex base-catalyzed degradation in alkaline solution, leading to the elimination of several small molecules. However, good long-term chemical stability was observed when PCysMA brushes were immersed in aqueous solution at physiological pH. PMID:24884533

  4. Uptake of isoprene, methacrylic acid and methyl methacrylate into aqueous solutions of sulfuric acid and hydrogen peroxide.

    PubMed

    Liu, Ze; Ge, Maofa; Wang, Weigang

    2012-01-01

    Multiphase acid-catalyzed oxidation by hydrogen peroxide has been suggested to be a potential route to secondary organic aerosol formation from isoprene and its gas-phase oxidation products, but the lack of kinetics data significantly limited the evaluation of this process in the atmosphere. Here we report the first measurement of the uptake of isoprene, methacrylic acid and methyl methacrylate into aqueous solutions of sulfuric acid and hydrogen peroxide. Isoprene cannot readily partition into the solution because of its high volatility and low solubility, which hinders its further liquid-phase oxidation. Both methacrylic acid and methyl methacrylate can enter the solutions and be oxidized by hydrogen peroxide, and steady-state uptake was observed with the acidity of solution above 30 wt.% and 70 wt.%, respectively. The steady-state uptake coefficient of methacrylic acid is much larger than that of methyl methacrylate for a solution with same acidity. These observations can be explained by the different reactivity of these two compounds caused by the different electron-withdrawing conjugation between carboxyl and ester groups. The atmospheric lifetimes were estimated based on the calculated steady-state uptake coefficients. These results demonstrate that the multiphase acid-catalyzed oxidation of methacrylic acid plays a role in secondary organic aerosol formation, but for isoprene and methyl methacrylate, this process is not important in the troposphere.

  5. Gelatin

    MedlinePlus

    ... recovery after exercise and sports-related injury. In manufacturing, gelatin is used for preparation of foods, cosmetics, ... animal sources. Some people are worried that unsafe manufacturing practices might lead to contamination of gelatin products ...

  6. 76 FR 69659 - Methacrylic Acid-Methyl Methacrylate-Polyethylene Glycol Monomethyl Ether Methacrylate Graft...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-11-09

    ... copolymer when used as an inert ingredient in a pesticide chemical formulation. Akzo Noel Surface Chemistry LLC submitted a petition to EPA under the Federal Food, Drug, and Cosmetic Act (FFDCA), requesting an... methacrylate graft copolymer on food or feed commodities. DATES: This regulation is effective November 9, 2011...

  7. Fabrication of gelatin methacrylate/nanohydroxyapatite microgel arrays for periodontal tissue regeneration

    PubMed Central

    Chen, Xi; Bai, Shizhu; Li, Bei; Liu, Huan; Wu, Guofeng; Liu, Sha; Zhao, Yimin

    2016-01-01

    Introduction Periodontitis is a chronic infectious disease and is the major cause of tooth loss and other oral health issues around the world. Periodontal tissue regeneration has therefore always been the ultimate goal of dentists and researchers. Existing fabrication methods mainly focused on a top–down tissue engineering strategy in which several drawbacks remain, including low throughput and limited diffusion properties resulting from a large sample size. Gelatin methacrylate (GelMA) is a kind of photocrosslinkable and biocompatible hydrogel, with the capacities of enabling cell encapsulation and regeneration of functional tissues. Here, we developed a novel method to fabricate GelMA/nanohydroxylapatite (nHA) microgel arrays using a photocrosslinkable strategy. The viability, proliferation, and osteogenic differentiation and in vivo osteogenesis of human periodontal ligament stem cells (hPDLSCs) encapsulated in microgels were evaluated. The results suggested that such microgels provide great potential for periodontal tissue repair and regeneration. Methods Microgel arrays were fabricated by blending different weight ratios of GelMA and nHA. hPDLSCs were encapsulated in GelMA/nHA microgels of various ratios for a systematic evaluation of cell viability, proliferation, and osteogenic differentiation. In vivo osteogenesis in nude mice was also studied. Results The GelMA/nHA microgels exhibited appropriate microarchitecture, mechanical strength, and surface roughness, thus enabling cell adhesion and proliferation. Additionally, the GelMA/nHA microgels (10%/2% w/v) enhanced the osteogenic differentiation of hPDLSCs by elevating the expression levels of osteogenic biomarker genes, such as ALP, BSP, OCN, and RUNX2. In vivo ectopic transplantation results showed that GelMA/nHA microgels (10%/2% w/v) increased mineralized tissue formation with abundant vascularization, compared with the 1%, 3%, and the pure GelMA group. Conclusion The GelMA/nHA microgels (10%/2% w

  8. Fabrication of gelatin methacrylate/nanohydroxyapatite microgel arrays for periodontal tissue regeneration.

    PubMed

    Chen, Xi; Bai, Shizhu; Li, Bei; Liu, Huan; Wu, Guofeng; Liu, Sha; Zhao, Yimin

    Periodontitis is a chronic infectious disease and is the major cause of tooth loss and other oral health issues around the world. Periodontal tissue regeneration has therefore always been the ultimate goal of dentists and researchers. Existing fabrication methods mainly focused on a top-down tissue engineering strategy in which several drawbacks remain, including low throughput and limited diffusion properties resulting from a large sample size. Gelatin methacrylate (GelMA) is a kind of photocrosslinkable and biocompatible hydrogel, with the capacities of enabling cell encapsulation and regeneration of functional tissues. Here, we developed a novel method to fabricate GelMA/nanohydroxylapatite (nHA) microgel arrays using a photocrosslinkable strategy. The viability, proliferation, and osteogenic differentiation and in vivo osteogenesis of human periodontal ligament stem cells (hPDLSCs) encapsulated in microgels were evaluated. The results suggested that such microgels provide great potential for periodontal tissue repair and regeneration. Microgel arrays were fabricated by blending different weight ratios of GelMA and nHA. hPDLSCs were encapsulated in GelMA/nHA microgels of various ratios for a systematic evaluation of cell viability, proliferation, and osteogenic differentiation. In vivo osteogenesis in nude mice was also studied. The GelMA/nHA microgels exhibited appropriate microarchitecture, mechanical strength, and surface roughness, thus enabling cell adhesion and proliferation. Additionally, the GelMA/nHA microgels (10%/2% w/v) enhanced the osteogenic differentiation of hPDLSCs by elevating the expression levels of osteogenic biomarker genes, such as ALP, BSP, OCN, and RUNX2. In vivo ectopic transplantation results showed that GelMA/nHA microgels (10%/2% w/v) increased mineralized tissue formation with abundant vascularization, compared with the 1%, 3%, and the pure GelMA group. The GelMA/nHA microgels (10%/2% w/v) facilitated hPDLSCs viability

  9. Some aspects of the host response to methacrylic acid containing beads in a mouse air pouch.

    PubMed

    Patel, Riteshkumar J; Sefton, Michael V

    2012-08-01

    Exudate analysis indicated that both hydroxamated methacrylic acid-based (HX-MAA) and methacrylic acid-based (MAA) beads without hydroxamation, implanted in an air pouch with gelatin discs, elicited similar biological responses, with both resulting in high cell counts and chemokine (MCP3) levels, relative to control, poly(methyl methacrylate) (PMMA) beads. HX-MAA beads had been used elsewhere to restore homeostatic levels of extracellular matrix degrading enzymes, matrix metalloproteases, whereas the MAA beads (without hydroxamation) promoted angiogenesis in wound healing models. Furthermore, both beads appeared to activate exudate macrophages in the classical manner (high IL12/IL10 ratio) at day 4. Exudate macrophages, which were isolated by a magnetic bead protocol and analyzed by RT-PCR, showed a mixed response: elevated levels of an alternative marker (mannose receptor C type lectin) and a classical marker (IL6) were seen, in macrophages from the HX-MAA and MAA group compared to the PMMA group at day 4. A partial shift to an alternatively activated phenotype was seen by day 10. Copyright © 2012 Wiley Periodicals, Inc.

  10. Effect of methacrylic acid:methyl methacrylate monomer ratios on polymerization rates and properties of polymethyl methacrylates.

    PubMed

    Chen, T; Kusy, R P

    1997-08-01

    Five binary formulations were prepared from methyl methacrylate (MMA) and methacrylic acid (MAA) monomers, and six ternary formulations were prepared from polysols of 30% wt polymethyl methacrylate (PMMA)/MMA and MAA. Using thermal analyses (DSC and TGA) the polymerization kinetics, condition of postcuring, relative amount of residual monomers, and glass transition temperature (Tg) were determined. From bar-shaped samples, 25 x 5 x 0.9 mm in dimensions, mechanical properties [flexural moduli (E) and maximum strengths (sigma)] were measured in three-point bending. Polymerization kinetics of binary formulations improved over pure PMMA (from 15 to 4 min) as a result of over a 60-fold increase in propagation-to-termination constants (Kp/Kt) of MAA/MMA. The further addition of PMMA increased the viscosity, slowed down termination, and, consequently, improved the polymerization kinetics twofold. These enhancements occurred without a substantive change in the Tg of the ternary system (ca. 107 degrees C) over pure PMMA (ca. 112 degrees C). Moreover, the Es of the four ternary formulations averaged 2.94 GPa, which was comparable with many values reported in the literature. In contrast the sigma s of these same formulations averaged 97 MPa, which was about 25% better than earlier investigations of pure acrylic. When a thermoplastic material is required for pultruding profiles that cure fast and have good thermal-mechanical properties, ternaries of PMMA/MMA/MAA should be considered.

  11. Novel glycidyl methacrylated dextran (Dex-GMA)/gelatin hydrogel scaffolds containing microspheres loaded with bone morphogenetic proteins: formulation and characteristics.

    PubMed

    Chen, Fa-Ming; Zhao, Yi-Min; Sun, Hai-Hua; Jin, Tao; Wang, Qin-Tao; Zhou, Wei; Wu, Zhi-Fen; Jin, Yan

    2007-03-12

    Novel thermomechanical hydrogel scaffolds containing our previously prepared microspheres loaded with bone morphogenetic proteins (BMP) were successfully generated by radical crosslinking and low dose gamma-irradiation from combination of two kind of biomaterials: glycidyl methacrylated dextran (Dex-GMA) and gelatin. The structure of those resulting smart hybrid hydrogels was evaluated by mercury intrusion porosimetry (MIP) and scanning electron microscopy (SEM) analyses, and as a function of the degree of Dex-GMA's substitution (DS), the proportion between Dex-GMA and gelatin, and the initial polyethyleneglycol (PEG) concentration used in the preparation of the hydrogels. The swelling and degradation properties and the temperature-sensitive drug release manner were determined by dynamic evaluation methods in vitro, and the gel content was also calculated. MIP analysis showed that by systematically altering the preparation parameters, the overall networks were clearly macroporous with pore sizes ranging from 5.6+/-4.2 to 37.7+/-13.7 microm. As expected, the pore size decreased as DS and initial PEG concentration increased, whereas the opposite was found for the gel content. Moreover, the porosity values ranged from 73.7+/-12.4% up to 89.6+/-6.3%. The SEM results also showed the inter-connective pores as well as microspheres encased into their porous structure of those hydrogels. The swelling and degradation properties of the resultant hydrogels varied according to the DS of Dex-GMA and initial PEG concentration, while the proportion between Dex-GMA and gelatin had no significant influence on those characterizations. By changing the composition ratio of the two precursors, the phase transition temperature (lower critical solution temperature, LSCT) of the hydrogel scaffolds could also be adjusted to be or near the body temperature, so BMP release from microsphere-hydrogel compounds could be accordingly controlled and the release period could be varied from 18 to

  12. Protonation of diethylaminoethyl methacrylate by acids in various solvents

    SciTech Connect

    Zhuravleva, I.L.; Bune, E.V.; Bogachev, Yu.S.; Sheinker, A.P.; Teleshov, E.N.

    1988-04-10

    It was established by /sup 1/H and /sup 13/C NMR that diethylaminoethyl methacrylate exists in the unprotonated form in solvents which are not acids. In the presence of an equimolar amount of hydrochloric or trifluoroacetic acids the amino ester is fully protonated, irrespective of the solvent. The diethylaminoethyl methacrylate-acetic acid system exists in the form of a molecular complex with a hydrogen bond and in the protonated form; the proportions of the protonated form were estimated in various solvents. The change in the reactivity of diethylaminoethyl methacrylate and its salts in polymerization was explained by a change in the electronic state of CH/sub 2/ = group of the monomer as a result of its protonation and of the formation of a hydrogen bond between the C = O group of the monomer and the solvent.

  13. A biomimetic hydrogel based on methacrylated dextran-graft-lysine and gelatin for 3D smooth muscle cell culture.

    PubMed

    Liu, Yunxiao; Chan-Park, Mary B

    2010-02-01

    Many synthetic hydrogels for cell encapsulation have hitherto been based on polyethylene glycol which is non-natural, non-biodegradable and only terminal-functionalizable, all of which are drawbacks for tissue engineering or cell delivery. The polysaccharide dextran is also highly hydrophilic but biodegradable and pendant-functionalizable and more closely resembles glycosaminoglycans to mimic the natural extracellular matrix. This study reports synthesis of a methacrylate and lysine functionalized dextran and development of hydrogel composite systems based on this material and methacrylamide modified gelatin. The mechanical stiffness and degree of swelling of the hydrogels were varied by manipulation of the degree of functionalization of dextran and gelatin and concentration/composition of precursor solution. Human umbilical artery smooth muscle cells (SMCs) were encapsulated inside hydrogels during gel hardening with photopolymerization. Rapid cell spreading, extensive cellular network formation and high SMC proliferation occurred within softer hydrogels (with shear storage moduli ranging from 898 to 3124Pa). The encapsulated SMCs appear to be relatively contractile in the initial culture than on tissue culture polystyrene dish due to physical constraint imposed by the hydrogels but they become more synthetic with time possibly due to the inability of cells to reach confluence inside these cell-mediated degradable hydrogels. From the impressive cell proliferation and network formation, these new hydrogels combining polysaccharide and protein derivatives appear to be excellent candidates for further development as bioactive scaffolds for use in vascular tissue engineering and regeneration.

  14. Synthesis and Characterization of Gelatin-Based Crosslinkers for the Fabrication of Superabsorbent Hydrogels

    PubMed Central

    Amonpattaratkit, Penphitcha; Khunmanee, Sureerat; Kim, Dong Hyun; Park, Hansoo

    2017-01-01

    In this work, crosslinkers were prepared by conjugating high- and low-molecular-weight gelatin with different mole ratios of itaconic acid (IA) with double bonds. Then, the gelatin-itaconic acid (gelatin-IA) crosslinkers were compared with the gelatin-methacrylate (gelatin-MA) crosslinkers. The molecular weights and structures of gelatin-MA and gelatin-IA were confirmed using gel permeation chromatography (GPC) and nuclear magnetic resonance (NMR). Additionally, the swelling ratio and biodegradation properties of the hydrogels using IA as starting monomers and gelatin-IA and gelatin-MA as crosslinkers were investigated. Both hydrogels prepared with high and low molecular weights of gelatin-IA showed higher swelling ratios than those prepared with the gelatin-MA. The results also showed that absorbent hydrogels with different biodegradabilities and swelling ratios could be prepared by changing the ratio of the gelatin-based crosslinkers. PMID:28773186

  15. Improvement of holographic thermal stability in phenanthrenequinone-doped poly(methyl methacrylate-co-methacrylic acid) photopolymer

    NASA Astrophysics Data System (ADS)

    Yu, Dan; Liu, Hongpeng; Wang, Heng; Wang, Jian; Jiang, Yongyuan; Sun, Xiudong

    2011-08-01

    Experimental studies of holographic thermal stability in phenanthrenequinone (PQ)-doped poly(methyl methacrylate-co-methacrylic acid) [P(MMA-co-MAA)] photopolymers are presented. A possibility to improve the thermal stability of holograms is demonstrated by doping methacrylic acid (MAA) into the poly(methyl methacrylate) (PMMA) polymer matrix. MAA as a copolymerization monomer can form a more stable polymer matrix with methyl methacrylate (MMA) monomer and increase average molecular weight of photoproducts, which finally depress the diffusion of photoproduct. The optimized MAA concentration copolymerized into P(MMA-co-MAA) polymer matrix can bring nearly a month's lifetime of gratings, which is obviously an improvement over the usual PQ-PMMA material under thermal treatment.

  16. Properties of electrospun pollock gelatin/poly(vinyl alcohol) and pollock gelatin/poly(lactic acid) fibers

    USDA-ARS?s Scientific Manuscript database

    Pollock gelatin/poly(vinyl alcohol) (PVA) fibers were electrospun using deionized water as the solvent and pollock gelatin/poly(lactic acid) (PLA) fibers were electrospun using 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP) as the solvent. The chemical, thermal, and thermal stability properties were exami...

  17. Engineering three-dimensional macroporous hydroxyethyl methacrylate-alginate-gelatin cryogel for growth and proliferation of lung epithelial cells.

    PubMed

    Singh, Deepti; Zo, Sun Mi; Kumar, Ashok; Han, Sung Soo

    2013-01-01

    Three-dimensional (3D) growth of cell is of particular interest in the field of tissue engineering and regenerative medicine. Scaffolds used for this purpose are often tailor-made to mimic the microenvironment and the extracellular matrix of the tissue with defined role such as to provide appropriate structural, chemical, and mechanical support. The aim of the study was to design the macroporous matrix with potential in the field of tissue engineering especially for lung muscle regeneration. Blend of hydroxyethyl methacrylate-alginate-gelatin (HAG) cryogel scaffold was synthesized using cryogelation technique and this polymer material combination is being reported first time. The rheology study showed the elastic property of the material in wet state with no variation in storage modulus (G'), loss modulus (G″), and phase angle upon temperature variation. The microcomputer tomography (micro-CT) analysis confirmed the homogenous polymer structure with average pore diameter of 84 μm. Scaffold synthesized using polymer combinations which is mixture of polysaccharide (alginate) and protein (gelatin) provides supportive environment for human lung epithelial cell proliferation confirmed by cytoskeletal stain phalloidin and nuclei staining 4',6-diamidino-2-phenylindole checked for over three weeks. The in vivo biocompatibility was further performed which showed integration of scaffold to the surrounding tissue with ability to recruit cells. However, at first week, small amount of infiltrating mast cells were found which subsequently diminished in following weeks. Immunohistochemistry for dendritic cells confirmed in vivo biocompatible nature of the HAG scaffold. The mechanical strength, stiffness, elastic measurements, in vivo compatibility, and in vitro lung cell proliferation show the potentiality of HAG materials for lung tissue engineering.

  18. Surface activity and molecular characteristics of cuttlefish skin gelatin modified by oxidized linoleic acid.

    PubMed

    Aewsiri, Tanong; Benjakul, Soottawat; Visessanguan, Wonnop; Wierenga, Peter A; Gruppen, Harry

    2011-05-01

    Surface activity and molecular changes of cuttlefish skin gelatin modified with oxidized linoleic acid (OLA) prepared at 60, 70 and 80 °C at different times were investigated. Modification of gelatin with OLA could improve surface activity of resulting gelatin as evidenced by the decreased surface tension and the increased foaming and emulsifying properties. Interaction between OLA and gelatin led to the generation of carbonyl groups, loss of free amino content and the increase in particle size of resulting gelatin. Emulsion stabilized by modified gelatin had the smaller mean particle diameter with higher stability, compared with that stabilized by gelatin without modification.

  19. Gelatin Methacrylate Hydrogels as Biomimetic Three-Dimensional Matrixes for Modeling Breast Cancer Invasion and Chemoresponse in Vitro.

    PubMed

    Arya, Anuradha D; Hallur, Pavan M; Karkisaval, Abhijith G; Gudipati, Aditi; Rajendiran, Satheesh; Dhavale, Vaibhav; Ramachandran, Balaji; Jayaprakash, Aravindakshan; Gundiah, Namrata; Chaubey, Aditya

    2016-08-31

    Recent studies have shown that three-dimensional (3D) culture environments allow the study of cellular responses in a setting that more closely resembles the in vivo milieu. In this context, hydrogels have become popular scaffold options for the 3D cell culture. Because the mechanical and biochemical properties of culture matrixes influence crucial cell behavior, selecting a suitable matrix for replicating in vivo cellular phenotype in vitro is essential for understanding disease progression. Gelatin methacrylate (GelMA) hydrogels have been the focus of much attention because of their inherent bioactivity, favorable hydration and diffusion properties, and ease-of-tailoring of their physicochemical characteristics. Therefore, in this study we examined the efficacy of GelMA hydrogels as a suitable platform to model specific attributes of breast cancer. We observed increased invasiveness in vitro and increased tumorigenic ability in vivo in breast cancer cells cultured on GelMA hydrogels. Further, cells cultured on GelMA matrixes were more resistant to paclitaxel treatment, as shown by the results of cell-cycle analysis and gene expression. This study, therefore, validates GelMA hydrogels as inexpensive, cell-responsive 3D platforms for modeling key characteristics associated with breast cancer metastasis, in vitro.

  20. Release of Water Soluble Drugs from Dynamically Swelling POLY(2-HYDROXYETHYL Methacrylate - CO - Methacrylic Acid) Hydrogels.

    NASA Astrophysics Data System (ADS)

    Kou, Jim Hwai-Cher

    In this study, ionizable copolymers of HEMA and methacrylic acid (MA) are investigated for their potential use in developing pH dependent oral delivery systems. Because of the MA units, these gels swell extensively at high pH. Since solute diffusion in the hydrophilic polymers depends highly on the water content of the matrix, it is anticipated that the release rate will be modulated by this pH induced swelling. From a practical point of view, the advantage of the present system is that one can minimize drug loss in the stomach and achieve a programmed release in intestine. This approach is expected to improve delivery of acid labile drugs or drugs that cause severe gastrointestinal side effects. This work mainly focuses on the basic understanding of the mechanism involved in drug release from the poly(HEMA -co- MA) gels, especially under dynamic swelling conditions. Equilibrium swelling is first characterized since water content is the major determinant of transport properties in these gels. Phenylpropanolamine (PPA) is chosen as the model drug for the release study and its diffusion characteristics in the gel matrix determined. The data obtained show that the PPA diffusivity follows the free volume theory of Yasuda, which explains the accelerating effect of swelling on drug release. A mathematical model based on a diffusion mechanism has been developed to describe PPA release from the swelling gels. Based on this model, several significant conclusions can be drawn. First, the release rate can be modulated by the aspect ratio of the cylindrical geometry, and this has a practical implication in dosage form design. Second, the release rate can be lowered quite considerably if the dimensional increase due to swelling is significant. Consequently, it is the balance between the drug diffusivity increase and the gel dimensional growth that determines the release rate from the swelling matrix. Third, quasi-steady release kinetics, which are characteristic of swelling

  1. Evaluation of tilapia skin gelatin as a mammalian gelatin replacer in acid milk gels and low-fat stirred yogurt.

    PubMed

    Pang, Zhihua; Deeth, Hilton; Yang, Hongshun; Prakash, Sangeeta; Bansal, Nidhi

    2017-05-01

    Tilapia skin gelatin (TSG) was studied in a 3-stage process (cooling, annealing, and heating) for pure gelatin gels and in a 4-stage process (acidification, cooling, annealing, and heating) for acid milk gels and cultured yogurt. The aim was to evaluate the use of TSG as a replacement for mammalian gelatin in yogurt. In pure TSG gels, stronger gels with higher melting temperatures were formed with increasing TSG concentrations. Compared with bovine gelatin (BG), which gelled at a concentration of 2.5%, TSG gels had lower gelling (14.1°C) and melting (24°C) temperatures but comparable storage moduli during annealing. In acid milk gels, addition of TSG increased the firmness of the gels with increasing concentration. Gelling and melting points of TSG in milk gels were observed at sufficient concentrations during cooling and heating. Strands and sheets were observed in the electron micrographs of milk gels with 1% TSG and a very dense structure was observed with 2.5% TSG. Yogurt with 0.4% TSG had similar viscosity, consistency, pseudoplasticity, and thixotropy as yogurt containing 0.4% BG; no difference was perceived by sensory panelists according to a triangle test. Addition of 0.4% TSG completely prevented whey separation from the acid milk gel and yogurt. The results suggest that TSG could be a suitable replacement for mammalian gelatin in low-fat stirred yogurt. Copyright © 2017 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  2. Surface functionalization of graphene oxide with poly(2-hydroxyethyl methacrylate)- graft-poly(ɛ-caprolactone) and its electrospun nanofibers with gelatin

    NASA Astrophysics Data System (ADS)

    Massoumi, Bakhshali; Ghandomi, Fereshteh; Abbasian, Mojtaba; Eskandani, Morteza; Jaymand, Mehdi

    2016-12-01

    This article describes covalent functionalization of graphene oxide (GO) with poly(2-hydroxyethyl methacrylate)- graft-poly(ɛ-caprolactone) [P(HEMA- g-CL)] via `living' polymerization techniques and preparation of its electrospun nanofibers with gelatin. For this purpose, the GO was synthesized by oxidizing pristine graphite powder and then acetyl chloride was incorporated into the GO to afford an atom transfer radical polymerization (ATRP) macroinitiator (GO-Cl). The synthesized macroinitiator was employed for HEMA polymerization via ATRP technique to produce GO- g-PHEMA. Afterward, CL was graft copolymerized from the hydroxyl groups of the PHEMA via ring-opening polymerization approach to afford GO- g-[P(HEMA- g-CL)] nanocomposite. The solutions of the GO- g-[P(HEMA- g-CL)] and gelatin were electrospun to fabricate uniform, conductive, and biocompatible nanofibers. The morphology, in vitro degradability, biocompatibility, hydrophilicity, and conductivity of the GO- g-[P(HEMA- g-CL)]/gelatin electrospun nanofibers were investigated. It is expected that the prepared nanofibers find application as a scaffolding biomaterial for regenerative medicine, mainly due to their biocompatibility, degradability, and electrical conductivity.

  3. Polydopamine-Gelatin as Universal Cell-Interactive Coating for Methacrylate-Based Medical Device Packaging Materials: When Surface Chemistry Overrules Substrate Bulk Properties.

    PubMed

    Van De Walle, Elke; Van Nieuwenhove, Ine; Vanderleyden, Els; Declercq, Heidi; Gellynck, Karolien; Schaubroeck, David; Ottevaere, Heidi; Thienpont, Hugo; De Vos, Winnok H; Cornelissen, Maria; Van Vlierberghe, Sandra; Dubruel, Peter

    2016-01-11

    Despite its widespread application in the fields of ophthalmology, orthopedics, and dentistry and the stringent need for polymer packagings that induce in vivo tissue integration, the full potential of poly(methyl methacrylate) (PMMA) and its derivatives as medical device packaging material has not been explored yet. We therefore elaborated on the development of a universal coating for methacrylate-based materials that ideally should reveal cell-interactivity irrespective of the polymer substrate bulk properties. Within this perspective, the present work reports on the UV-induced synthesis of PMMA and its more flexible poly(ethylene glycol) (PEG)-based derivative (PMMAPEG) and its subsequent surface decoration using polydopamine (PDA) as well as PDA combined with gelatin B (Gel B). Successful application of both layers was confirmed by multiple surface characterization techniques. The cell interactivity of the materials was studied by performing live-dead assays and immunostainings of the cytoskeletal components of fibroblasts. It can be concluded that only the combination of PDA and Gel B yields materials possessing similar cell interactivities, irrespective of the physicochemical properties of the underlying substrate. The proposed coating outperforms both the PDA functionalized and the pristine polymer surfaces. A universal cell-interactive coating for methacrylate-based medical device packaging materials has thus been realized.

  4. Obtainment and partial characterization of biodegradable gelatin films with tannic acid, bentonite and glycerol.

    PubMed

    Ortiz-Zarama, Maria A; Jiménez-Aparicio, Antonio R; Solorza-Feria, Javier

    2016-08-01

    Research studies concerning the overall effect of the addition of plasticizers, cross-linking and strengthening agents in gelatin film-forming mixtures are very scarce. Also, there are no studies focused on the interactions among their individual components, or showing what sort of effects they might cause all together. A gelatin film obtained from a composite consisting of tannic acid, bentonite and glycerol was evaluated. Nine gelatin films were manufactured by the casting method, using these materials, following a 2(3) factorial design with five replicates on the central point. The interactions among gelatin, tannic acid and bentonite caused a decrease in hydrogen bonds, while the polar groups of the gelatin chains were less exposed to interactions with water molecules. There was an increase in temperature and enthalpy of gelatin denaturation, due to increasing tannic acid and bentonite concentration. Tactoids were found in the gelatin films, caused mainly by bentonite polydispersion. A synergistic effect among tannic acid, bentonite and glycerol, which overall improved the measured gelatin film properties, was found. The best film formulation was that with 40, 150 and 250 g kg(-1) gelatin of tannic acid, bentonite and glycerol respectively, displaying a tensile strength of 38 MPa, an elongation at break of 136%, water vapor permeability of 1.28 × 10(-12) g (Pa s m)(-1) and solubility of 23.4%. © 2015 Society of Chemical Industry. © 2015 Society of Chemical Industry.

  5. Poly(methacrylic acid-co-methyl methacrylate) beads promote vascularization and wound repair in diabetic mice.

    PubMed

    Martin, Daniel C; Semple, John L; Sefton, Michael V

    2010-05-01

    Topical application of beads made from poly(methacrylic acid-co-methyl methacrylate) (45 mol % methacrylic acid, MAA) increased the number of blood vessels and improved 1.5 x 1.5 cm full thickness wound closure in a diabetic mouse (db/db) model. Three groups were compared: MAA beads, control poly(methyl methacrylate) beads (PMMA), and no bead blanks. MAA bead treatment significantly increased percent wound closure at all timepoints (7, 14, and 21 days) with MAA bead-treated wounds almost closed at day 21 (91 +/- 5.4% MAA vs. 79 +/- 3.2% PMMA or 76 +/- 4.8% no beads; p < 0.05). This was consistent with the expected significant increase in vascularity in the MAA group at days 7 and 14. For example at day 14, MAA bead-treated wounds had a vascular density of 22.7 +/- 2.6 vessels/hpf compared with 17.0 +/- 2.0 vessels/hpf in the PMMA bead group (p < 0.05). Epithelial gap and migration measurements suggested that the increased vascularity leads to enhanced epithelial cell migration as a principal means of wound closure. Although studies are underway to elucidate the mechanism of this angiogenic response, the results presented here support the notion that such materials, perhaps in other forms, may be useful in wound care or in other situations where vascularity is to be enhanced without the use of exogenous growth factors.

  6. Radiation synthesis of nanosilver nanohydrogels of poly(methacrylic acid)

    NASA Astrophysics Data System (ADS)

    Gupta, Bhuvanesh; Gautam, Deepti; Anjum, Sadiya; Saxena, Shalini; Kapil, Arti

    2013-11-01

    Nanosilver nanohydrogels (nSnH) of poly(methacrylic acid) were synthesized and stabilized using gamma irradiation. The main objective of this study was to develop silver nanoparticles and to evaluate the antimicrobial activity. Radiation helps in the polymerization, crosslinking and reduction of silver nitrate as well. Highly stable and uniformly distributed silver nanoparticles have been obtained within hydrogel network by water in oil nanoemulsion polymerization and were evaluated by dynamic light scattering (DLS) and transmission electron microscopy (TEM) respectively. TEM showed almost spherical and uniform distribution of silver nanoparticles through the hydrogel network. The mean size of silver nanoparticles ranging is 10-50 nm. The nanohydrogels showed good swelling in water. Antibacterial studies of nSnH suggest that it can be a good candidate as coating material in biomedical applications.

  7. Influence of tannic acid and polyethylene glycol on the excretion and digestibility of amino acids in gelatin-fed broilers.

    PubMed

    Mansoori, B; Acamovic, T

    2009-03-01

    1. A precision feeding experiment was conducted to evaluate the effects of tannic acid (TA) and polyethylene glycol (PEG) on the excretion of amino acids, and the apparent and true digestibility of gelatin protein in broilers. 2. In a 3 x 2 x 2 factorial design, ninety-six 7-week-old broiler cockerels in 8 replicates of 12 treatments, were fed on warm solution of gelatin alone (0, 6 or 12 g/50 ml/bird, Treatments 1-3), or gelatin with TA solution (4.5 g TA/10 ml/bird, Treatments 4-6) and PEG solution (2 g/10 ml/bird, Treatments 7-12). Total excreta were collected for 48 h and the amino acid contents of gelatin and excreta were determined. 3. In the absence of TA, the digestibility of gelatin was almost complete. TA increased the excretion of amino acids from gelatin-fed birds to varying extents. Although the digestibility of all indispensable and dispensable amino acids was adversely affected by the presence of TA, increasing the amount of gelatin from 6 to 12 g improved the apparent and true digestibility of amino acids. PEG reduced the excretion of amino acids and improved the digestibility of amino acids in gelatin in TA-dosed birds. However, the effect was greater when the lesser amount of gelatin was fed. 4. In conclusion, PEG seemed to play an important role in reducing the effect of dietary tannins in the gastrointestinal tract of birds fed on diets high in tannins and improved protein digestibility and utilisation, particularly when the diet was low or marginal in protein.

  8. Conversion of (Meth)acrylic acids to methane granular sludge: Initiation by specific anerobic microflora

    SciTech Connect

    Shtarkman, N.B.; Obraztova, A.Y.; Laurinavichyus, K.S.; Galushko, A.S.; Akimenko, V.K.

    1995-03-01

    The role of a specific anaerobic microflora in the initiation of degradation of (meth)acrylic acids to methane by granular sludge from a UASB reactor was investigated. Associations of anaerobic bacteria isolated from the anaerobic sludge, which was used for a long time for treatment of wastewater from (meth)acrylate production, were able to realize the initial stage of (meth)acrylic acid decomposition, i.e., a conversion of acrylic and methacrylic acids to propionic and isobutyric acids, respectively. When added to granules, these association played a role of an {open_quotes}initiator{close_quotes} of the degradation process, which was then continued by the granular sludge microflora utilizing propionate and isobutyrate. Some characteristics of the granules adapted to propionate or isobutyrate are presented. The rates of propionate and isobutyrate consumption by adapted granules is, respectively, 21 and 53 times higher than the values obtained for nonadapted granules. A combined use of {open_quotes}initiating{close_quotes} bacteria and adapted granules provided degradation of (meth)acrylic acids with a maximum methane yield. The possibility is discussed of employing the granules, which are adapted to short-chain fatty acids, and the {open_quotes}initiating{close_quotes} bacteria, which accomplish the initial steps of the organic material decomposition to lower fatty acids, for the conversion of various chemical compounds to methane. 10 refs., 3 figs., 2 tabs.

  9. The chitosan-gelatin (bio)polyelectrolyte complexes formation in an acidic medium.

    PubMed

    Voron'ko, Nicolay G; Derkach, Svetlana R; Kuchina, Yuliya A; Sokolan, Nina I

    2016-03-15

    The interaction of cationic polysaccharide chitosan and gelatin accompanied by the stoichiometric (bio)polyelectrolyte complexes formation has been studied by the methods of capillary viscometry, UV and FTIR spectroscopy and dispersion of light scattering. Complexes were formed in the aqueous phase, with pH being less than the isoelectric point of gelatin (pIgel). The particle size of the disperse phase increases along with the growth of the relative viscosity in comparison with sols of the individual components-polysaccharide and gelatin. Possible models and mechanism of (bio)polyelectrolyte complexes formation have been discussed. It was shown that the complex formation takes place not only due to the hydrogen bonds, but also due to the electrostatic interactions between the positively charged amino-groups of chitosan and negatively charged amino acid residues (glutamic Glu and aspartic Asp acids) of gelatin. Copyright © 2015 Elsevier Ltd. All rights reserved.

  10. Monitoring of acid-base status of workers at a methyl methacrylate and polymethyl methacrylate production plant in Bulgaria.

    PubMed

    Prakova, Gospodinka R

    2003-01-01

    This study was carried out on 104 workers at three work operations and a control (nonproduction) area, within a methyl methacrylate (MMA)/polymethyl methacrylate (PMMA) production facility in Bulgaria. Airborne monitoring was conducted over a 10-year period for MMA and the reactant chemicals methanol and acetone cyanhydrine at the MMA operation, and MMA was monitored at the PMMA operation. Acid-base status of the workers was evaluated using traditional criteria (pH, pCO(2), pO(2), and HCO(3) in plasma). Data from retrospective monitoring of air levels of the chemicals were compared with the acid-base status of workers at the plant. In some cases air concentrations exceeded the threshold limit value, with the highest percentage of overexposure occurring with airborne MMA in the PMMA production operation. Acid-base disruption indicated by reductions in plasma pH and HCO(3) was found for all groups except the control population. The highest percentage reduction was associated with PMMA production workers. Additionally, respiratory acidosis, indicated by increased pCO(2), was noted in the MMA production and maintenance groups, implying that the response to MMA exposure may involve both the metabolic and respiratory acidosis component. This study was unique in that the combined exposure to MMA and the precursor chemical (methanol) were shown to produce the same effects in workers. It is suggested that when combined exposure occurs, disruption of acid-base status may occur. Enforcement of PPM requirements for coveralls and gloves should prevent skin contamination. Additionally, improvement of equipment in MMA and PMMA production areas is recommended: (1) automation of some manual operations; (2) use of respiratory protection during equipment cleaning; and (3) installation of local ventilation when applicable.

  11. Amino acid and proximate composition of fish bone gelatin from different warm-water species: A comparative study

    NASA Astrophysics Data System (ADS)

    Atma, Y.

    2017-03-01

    Research on fish bone gelatin has been increased in the last decade. The quality of gelatin depends on its physicochemical properties. Fish bone gelatin from warm-water fishes has a superior amino acid composition than cold-water fishes. The composition of amino acid can determine the strength and stability of gelatin. Thus, it is important to analyze the composition of amino acid as well as proximate composition for potential gelatin material. The warm water fish species used in this study were Grass carp, Pangasius catfish, Catfish, Lizard fish, Tiger-toothed croaker, Pink perch, Red snapper, Brown spotted grouper, and King weakfish. There werre five dominant amino acid in fish bone gelatin including glycine (21.2-36.7%), proline (8.7-11.7%), hydroxyproline (5.3-9.6%), alanine (8.48-12.9%), and glutamic acid (7.23-10.15%). Different warm-water species has some differences in amino acid composition. The proximate composition showed that fishbone gelatin from Pangasius catfish has the highest protein content. The water composition of all fishbone gelatin was well suited to the standard. Meanwhile, based on ash content, only gelatin from gelatin Pangasius catfish met the standard for food industries.

  12. Poly(2-hydroxyethyl methacrylate-co-dodecyl methacrylate-co-acrylic acid): synthesis, physico-chemical characterisation and nafcillin carrier.

    PubMed

    Zecheru, Teodora; Rotariu, Traian; Rusen, Edina; Mărculescu, Bogdan; Miculescu, Florin; Alexandrescu, Laura; Antoniac, Iulian; Stancu, Izabela-Cristina

    2010-10-01

    In the present study polymeric microbeads of poly(2-hydroxyethyl methacrylate-co-dodecyl methacrylate-co-acrylic acid) or p(HEMA-co-dDMA-co-AA) were synthesised and characterized through FT-IR and scanning electron microscopy (SEM); their swelling behavior against saline solution was explored and their in vitro cytotoxicity was evaluated. Further, in order to elucidate kinetic aspects regarding the ternary system p(HEMA-co-dDMA-co-AA), a mathematical model of the reactivity ratios of the comonomers in the terpolymer has been conceived and analyzed. An intensified tendency of AA units accumulation in the copolymer has been noticed, in spite of HEMA units, while dDMA conserves in the copolymer the fraction from the feed. Three compositions have been selected for nafcillin-loading and their in vitro release capacity was evaluated. The compositions of 80:10:10 and 75:10:15 M ratios appear suitable for further in vivo testing, in order to be used as drug delivery systems in the treatment of different osseous diseases.

  13. Structural characterization of a poly(methacrylic acid)-poly(methyl methacrylate) copolymer by nuclear magnetic resonance and mass spectrometry.

    PubMed

    Giordanengo, Rémi; Viel, Stéphane; Hidalgo, Manuel; Allard-Breton, Béatrice; Thévand, André; Charles, Laurence

    2009-11-03

    Mass spectrometry (MS) and nuclear magnetic resonance (NMR) have been combined to achieve the complete microstructural characterization of a poly(methacrylic acid)-poly(methyl methacrylate) (PMAA-PMMA) copolymer synthesized by nitroxide-mediated polymerization. Various PMAA-PMMA species could be identified which mainly differ in terms of terminaisons. 1H and 13C NMR experiments revealed the structure of the end-groups as well as the proportion of each co-monomer in the copolymers. These end-group masses were further confirmed from m/z values of doubly charged copolymer anions detected in the single stage mass spectrum. In contrast, copolymer composition derived from MS data was not consistent with NMR results, obviously due to strong mass bias well known to occur during electrospray ionization of these polymeric species. Tandem mass spectrometry could reveal the random nature of the copolymer based on typical dissociation reactions, i.e., water elimination occurred from any two contiguous MAA units while MAA-MMA pairs gave rise to the loss of a methanol molecule. Polymer backbone cleavages were also observed to occur and gave low abundance fragment ions which allowed the structure of the initiating end-group to be confirmed.

  14. Analytical strategy for the molecular weight determination of random copolymers of poly(methyl methacrylate) and poly(methacrylic acid).

    PubMed

    Giordanengo, Rémi; Viel, Stéphane; Hidalgo, Manuel; Allard-Breton, Béatrice; Thévand, André; Charles, Laurence

    2010-06-01

    Molecular weight characterization of random amphiphilic copolymers currently represents an analytical challenge. In particular, molecules composed of methacrylic acid (MAA) and methyl methacrylate (MMA) as the repeat units raise issues in commonly used techniques. The present study shows that when random copolymers cannot be properly ionized by MALDI, and hence detected and measured in MS, one possible analytical strategy is to transform them into homopolymers, which are more amenable to this ionization technique. Then, by combining the molecular weight of the so-obtained homopolymers, as measured by MS, with the relative molar proportion of the MMA and MMA units, as given by (1)H NMR spectrum, one can straightforwardly estimate the molecular weight of the initial copolymer. A methylation reaction was performed to transform MAA-MMA copolymer samples into PMMA homopolymers, using trimethylsilyldiazomethane as a derivatization agent. Weight average molecular weight (M(w)) parameters of the MAA-MMA copolymers could then be derived from M(w) values obtained for the methylated MAA-MMA molecules by MALDI, which were also validated by pulsed gradient spin echo (PGSE) NMR. An alkene function in one of the studied copolymer end-groups was also shown to react with the methylation agent, giving rise to MMA-like polymeric by-products characterized by tandem mass spectrometry and which could be avoided by adjusting the amount of the trimethylsilyldiazomethane in the reaction medium.

  15. Preparation and evaluation of poly(alkyl methacrylate-co-methacrylic acid-co-ethylene dimethacrylate) monolithic columns for separating polar small molecules by capillary liquid chromatography.

    PubMed

    Lin, Shu-Ling; Wu, Yu-Ru; Lin, Tzuen-Yeuan; Fuh, Ming-Ren

    2015-04-29

    In this study, methacrylic acid (MAA) was incorporated with alkyl methacrylates to increase the hydrophilicity of the synthesized ethylene dimethacrylate-based (EDMA-based) monoliths for separating polar small molecules by capillary LC analysis. Different alkyl methacrylate-MAA ratios were investigated to prepare a series of 30% alkyl methacrylate-MAA-EDMA monoliths in fused-silica capillaries (250-μm i.d.). The porosity, permeability, and column efficiency of the synthesized MAA-incorporated monolithic columns were characterized. A mixture of phenol derivatives is employed to evaluate the applicability of using the prepared monolithic columns for separating small molecules. Fast separation of six phenol derivatives was achieved in 5 min with gradient elution using the selected poly(lauryl methacrylate-co-MAA-co-EDMA) monolithic column. In addition, the effect of acetonitrile content in mobile phase on retention factor and plate height as well as the plate height-flow velocity curves were also investigated to further examine the performance of the selected poly(lauryl methacrylate-co-MAA-co-EDMA) monolithic column. Moreover, the applicability of prepared polymer-based monolithic column for potential food safety applications was also demonstrated by analyzing five aflatoxins and three phenicol antibiotics using the selected poly(lauryl methacrylate-co-MAA-co-EDMA) monolithic column.

  16. Effects of charge-carrying amino acids on the gelatinization and retrogradation properties of potato starch.

    PubMed

    Chen, Wenting; Zhou, Hongxian; Yang, Hong; Cui, Min

    2015-01-15

    The objective of this study was to evaluate the effects of charge-carrying amino acids (lysine (Lys), arginine (Arg), aspartic acid (Asp) and glutamic acid (Glu)) on the gelatinization and retrogradation properties of potato starch. Acidic amino acids (Asp and Glu) showed a decreasing trend in swelling power and granule size of potato starch, but increased amylose leaching and gelatinization temperature. Alkaline amino acid (Arg) showed an increasing trend in swelling power and granule size of potato starch, but decreasing amylose leaching and gelatinization temperature. Lys had no effect on the swelling power of potato starch, except at a high content (0.2 mol/kg). Like other two acidic amino acids, Lys also increased gelatinization temperature. Moreover, the addition of alkaline amino acids (Arg) decreased syneresis value of potato starch but acidic amino acids (Asp and Glu) increased it. Compared to Arg, the syneresis of potato starch with Lys was similar to that of its native starch. Copyright © 2014 Elsevier Ltd. All rights reserved.

  17. Copolymer of methacrylic acid with its diethylammonium salt: Effective waterproofing agent for oil wells

    SciTech Connect

    Kuznetsova, O.N.; Avvakumova, N.I.

    1992-08-10

    In the development of technology for the copolymerization of methacrylic acid with its diethylammonium salt (MAA-MAA{center_dot}DEA), the polymer-like reaction of polymethacrylic acid (PMAA) with diethylamine (DEA) and the polymerization of MAA in the presence of DEA have been studied. 13 refs., 3 figs., 4 tabs.

  18. Enthalpy of mixing of methacrylic acid with organic solvents at 293 K

    NASA Astrophysics Data System (ADS)

    Sergeev, V. V.

    2016-03-01

    The enthalpies of mixing of binary systems of methacrylic acid with acetonitrile, benzene, hexane, 1,2-dichloroethane, and acetic acid are measured calorimetrically at 293 K and atmospheric pressure. The enthalpy of mixing of all the studied binary systems is positive over the range of concentrations.

  19. Viscoelasticity of hyaluronic acid-gelatin hydrogels for vocal fold tissue engineering

    PubMed Central

    Kazemirad, Siavash; Heris, Hossein K.; Mongeau, Luc

    2015-01-01

    Cross-linked injectable hyaluronic acid-gelatin hydrogels have remarkable viscoelastic and biological properties for vocal fold tissue engineering. Patient-specific tuning of the viscoelastic properties of this injectable biomaterial could improve tissue regeneration. The frequency-dependent viscoelasticity of cross-linked hyaluronic acid-gelatin hydrogels was measured as a function of the concentration of hyaluronic acid, gelatin, and cross-linker. Synthetic extracellular matrix hydrogels were fabricated using thiol-modified hyaluronic acid and gelatin, and cross-linked by Poly(ethylene glycol)diacrylate. A recently developed characterization method based on Rayleigh wave propagation was used to quantify the frequency-dependent viscoelastic properties of these hydrogels, including shear storage and loss moduli, over a broad frequency range; i.e., from 40 to 4000 Hz. The viscoelastic properties of the hydrogels increased with frequency. The storage and loss moduli values and the rate of increase with frequency varied with the concentrations of the constituents. The range of the viscoelastic properties of the hydrogels was within that of human vocal fold tissue obtained from in vivo and ex vivo measurements. Frequency-dependent parametric relations were obtained using a linear least-squares regression. The results are useful to better fine-tune the storage and loss moduli of hyaluronic acid-gelatin hydrogels by varying the concentrations of the constituents for use in patient-specific treatments. PMID:25728914

  20. Influence of gelatinization on the extraction of phenolic acids from wheat fractions

    USDA-ARS?s Scientific Manuscript database

    The effect of gelatinization on the analysis of phenolic acids from wheat bran, whole-wheat, and refined flour samples was investigated using two extraction procedures, namely, ultrasonic (UAE) and microwave (MAE). The total phenolic acid (TPA) concentration quantity in wheat bran (2711-2913 µg/g) w...

  1. Non-toxic agarose/gelatin-based microencapsulation system containing gallic acid for antifungal application.

    PubMed

    Lam, P-L; Gambari, R; Kok, S H-L; Lam, K-H; Tang, J C-O; Bian, Z-X; Lee, K K-H; Chui, C-H

    2015-02-01

    Aspergillus niger (A. niger) is a common species of Aspergillus molds. Cutaneous aspergillosis usually occurs in skin sites near intravenous injection and approximately 6% of cutaneous aspergillosis cases which do not involve burn or HIV-infected patients are caused by A. niger. Biomaterials and biopharmaceuticals produced from microparticle-based drug delivery systems have received much attention as microencapsulated drugs offer an improvement in therapeutic efficacy due to better human absorption. The frequently used crosslinker, glutaraldehyde, in gelatin-based microencapsulation systems is considered harmful to human beings. In order to tackle the potential risks, agarose has become an alternative polymer to be used with gelatin as wall matrix materials of microcapsules. In the present study, we report the eco-friendly use of an agarose/gelatin-based microencapsulation system to enhance the antifungal activity of gallic acid and reduce its potential cytotoxic effects towards human skin keratinocytes. We used optimal parameter combinations, such as an agarose/gelatin ratio of 1:1, a polymer/oil ratio of 1:60, a surfactant volume of 1% w/w and a stirring speed of 900 rpm. The minimum inhibitory concentration of microencapsulated gallic acid (62.5 µg/ml) was significantly improved when compared with that of the original drug (>750 µg/ml). The anti-A. niger activity of gallic acid -containing microcapsules was much stronger than that of the original drug. Following 48 h of treatment, skin cell survival was approximately 90% with agarose/gelatin microcapsules containing gallic acid, whereas cell viability was only 25-35% with free gallic acid. Our results demonstrate that agarose/gelatin-based microcapsules containing gallic acid may prove to be helpful in the treatment of A. niger-induced skin infections near intravenous injection sites.

  2. Radiation grafting of acrylic and methacrylic acid to cellulose fibers to impart high water sorbency

    SciTech Connect

    Zahran, A.H.; Williams, J.L.; Stannett, V.T.

    1980-04-01

    Acrylic and methacrylic acids have been directly grafted to rayon and cotton using the preirradiation technique with /sup 60/ Co gamma rays. The rate of grafting increased with increasing temperature and monomer concentration, as did the final degree of grafting. The amount and rate of grafting also increased with the total irradiation dose but tended to level off at higher doses, in agreement with the leveling off of the radical content reported previously. Methacrylic acid grafted more and faster than acrylic acid to both rayon and cotton. Methacrylic acid grafted more with rayon than cotton, but acrylic acid gave somewhat similar yields with both fibers. The water abosrbency of the grafted fibers depended strongly on their posttreatment. Decrystallizing with 70% zinc chloride or with hot sodium hydroxidy developed supersorbency. The two treatments in succession, respectively, gave the highest values. Metacrylic acid brought about less sorbency than the corrsponding acrylic acid grafts. Useful levels of grafting and supersorbency could be readily and practically achieved by the methods described.

  3. The acid solvent experimental studies on gelatin producing by utilizing snapper fishes scales waste (Lutjanus camphecanus sp.)

    NASA Astrophysics Data System (ADS)

    Faradiella, Hanandyta; Ningsih, Putri Dewi Fatwa; Triastuti, Warlinda Eka

    2017-03-01

    Had done research processing scales red snapper (Lutjanjus campechanus sp.) into gelatin by process of maseration a solution of citric acid, acetate acid, hydrochloric acid, and phosphoric acid an then continued with hydrolysis process. Concentration of solvent used 5% (% v/v) for 3 and 6 days. Gelatin produces then were analyzed fourier transform infrared spectroscopy (FTIR), proximate analysis include yield and the water content, analysis of physical-chemist properties include analysis viscosity and pH, organoleptic test (color, texture, odor). Analyst ftir results showed the presence of a cluster functions 0-H, C-H, C=0, N-H and C-C aromatis similar to those of spectra that are found on commercial gelatin. Gelatin best results obtained maseration on with phosphoricacid 5% viscosity of gelatin 3,91 cP, the water content 2,569%, pH 6,98 and yield 11,7448%.

  4. Dual-Responsive pH and Temperature Sensitive Nanoparticles Based on Methacrylic Acid and Di(ethylene glycol) Methyl Ether Methacrylate for the Triggered Release of Drugs.

    PubMed

    Khine, Yee Yee; Jiang, Yanyan; Dag, Aydan; Lu, Hongxu; Stenzel, Martina H

    2015-08-01

    A series of thermo-and pH-responsive poly(methyl methacrylate)-block-poly[methacrylic acid-co-di(ethylene glycol) methyl ether methacrylate] PMMA-b-P[MAA-co-DEGMA] block copolymers were synthesized by RAFT polymerization and self-assembled into micelles. The molar ratio of MAA was altered from 0-12% in order to modulate the lower critical solution temperature (LCST) of PDEGMA. The release of the drug albendazole from the micelle was strongly dependent on the temperature and the LCST value of the polymer. Systems below the LCST released the drug slowly while increasing the temperature above the LCST or decreasing the pH value to 5 resulted in the burst-like release of the drug. ABZ delivered in this pH-responsive drug carrier had a higher toxicity than the free drug or the drug delivered in a non-responsive drug carrier.

  5. Combinatory approach of methacrylated alginate and acid monomers for concrete applications.

    PubMed

    Mignon, Arn; Devisscher, Dries; Graulus, Geert-Jan; Stubbe, Birgit; Martins, José; Dubruel, Peter; De Belie, Nele; Van Vlierberghe, Sandra

    2017-01-02

    Polysaccharides, and especially alginate, can be useful for self-healing of cracks in concrete. Instead of weak electrostatic bonds present within calcium alginate, covalent bonds, by methacrylation of the polysaccharides, will result in mechanically stronger superabsorbent polymers (SAPs). These methacrylated alginate chains as backbone are combined with two acrylic monomers in a varying molar fraction. These SAPs show a moisture uptake capacity up to 110% their own weight at a relative humidity of 95%, with a negligible hysteresis. The swelling capacity increased (up to 246 times its own weight) with a decreasing acrylic acid/2 acrylamido-2-methylpropane sulfonic acid ratio. The SAPs also showed a thermal stability up to 200°C. Interestingly, the SAP composed of alginate and acrylic acid exerted a very limited decrease in compressive strength (up to 7% with addition of 1wt% SAP) rendering this material interesting for the envisaged self-healing application. Copyright © 2016 Elsevier Ltd. All rights reserved.

  6. Methylation of acidic moieties in poly(methyl methacrylate-co-methacrylic acid) copolymers for end-group characterization by tandem mass spectrometry.

    PubMed

    Giordanengo, Rémi; Viel, Stéphane; Hidalgo, Manuel; Allard-Breton, Béatrice; Thévand, André; Charles, Laurence

    2010-07-30

    The complete structural characterization of a copolymer composed of methacrylic acid (MAA) and methyl methacrylate (MMA) units was achieved using tandem mass spectrometry. In a first step, collision-induced dissociation (CID) of sodiated MAA-MMA co-oligomers allowed us to determine the co-monomeric composition, the random nature of the copolymer and the sum of the end-group masses. However, dissociation reactions of MAA-based molecules mainly involve the acidic pendant groups, precluding individual characterization of the end groups. Therefore, methylation of all the acrylic acid moieties was performed to transform the MAA-MMA copolymer into a PMMA homopolymer, for which CID mainly proceeds via backbone cleavages. Using trimethylsilyldiazomethane as a derivatization agent, this methylation reaction was shown to be complete without affecting the end groups. Using fragmentation rules established for PMMA polymers together with accurate mass measurements of the product ions and knowledge of reagents used for the studied copolymer synthesis, a structure could be proposed for both end groups and it was found to be consistent with signals obtained in nuclear magnetic resonance spectra.

  7. Use of Gallic Acid to Enhance the Antioxidant and Mechanical Properties of Active Fish Gelatin Film.

    PubMed

    Limpisophon, Kanokrat; Schleining, Gerhard

    2017-01-01

    This study explores the potential roles of gallic acid in fish gelatin film for improving mechanical properties, UV barrier, and providing antioxidant activities. Glycerol, a common used plasticizer, also impacts on mechanical properties of the film. A factorial design was used to investigate the effects of gallic acid and glycerol concentrations on antioxidant activities and mechanical properties of fish gelatin film. Increasing the amount of gallic acid increased the antioxidant capacities of the film measured by radical scavenging assay and the ferric reducing ability of plasma assay. The released antioxidant power of gallic acid from the film was not reduced by glycerol. The presence of gallic acid not only increased the antioxidant capacity of the film, but also increased the tensile strength, elongation at break, and reduced UV absorption due to interaction between gallic acid and protein by hydrogen bonding. Glycerol did not affect the antioxidant capacities of the film, but increased the elasticity of the films. Overall, this study revealed that gallic acid entrapped in the fish gelatin film provided antioxidant activities and improved film characteristics, namely UV barrier, strength, and elasticity of the film. © 2016 Institute of Food Technologists®.

  8. Synthesis of bio-based methacrylic acid by decarboxylation of itaconic acid and citric acid catalyzed by solid transition-metal catalysts.

    PubMed

    Le Nôtre, Jérôme; Witte-van Dijk, Susan C M; van Haveren, Jacco; Scott, Elinor L; Sanders, Johan P M

    2014-09-01

    Methacrylic acid, an important monomer for the plastics industry, was obtained in high selectivity (up to 84%) by the decarboxylation of itaconic acid using heterogeneous catalysts based on Pd, Pt and Ru. The reaction takes place in water at 200-250 °C without any external added pressure, conditions significantly milder than those described previously for the same conversion with better yield and selectivity. A comprehensive study of the reaction parameters has been performed, and the isolation of methacrylic acid was achieved in 50% yield. The decarboxylation procedure is also applicable to citric acid, a more widely available bio-based feedstock, and leads to the production of methacrylic acid in one pot in 41% selectivity. Aconitic acid, the intermediate compound in the pathway from citric acid to itaconic acid was also used successfully as a substrate.

  9. 2-hydroxylethyl methacrylate (HEMA), a tooth restoration component, exerts its genotoxic effects in human gingival fibroblasts trough methacrylic acid, an immediate product of its degradation.

    PubMed

    Szczepanska, Joanna; Poplawski, Tomasz; Synowiec, Ewelina; Pawlowska, Elzbieta; Chojnacki, Cezary J; Chojnacki, Jan; Blasiak, Janusz

    2012-02-01

    HEMA (2-hydroxyethyl methacrylate), a methacrylate commonly used in dentistry, was reported to induce genotoxic effects, but their mechanism is not fully understood. HEMA may be degraded by the oral cavity esterases or through mechanical stress following the chewing process. Methacrylic acid (MAA) is the primary product of HEMA degradation. In the present work we compared cytotoxic and genotoxic effects induced by HEMA and MAA in human gingival fibroblasts (HGFs). A 6-h exposure to HEMA or MAA induced a weak decrease in the viability of HGFs. Neither HEMA nor MAA induced strand breaks in the isolated plasmid DNA, but both compounds evoked DNA damage in HGFs, as evaluated by the alkaline comet assay. Oxidative modifications to the DNA bases were monitored by the DNA repair enzymes Endo III and Fpg. DNA damage induced by HEMA and MAA was not persistent and was removed during a 120 min repair incubation. Results from the neutral comet assay indicated that both compounds induced DNA double strand breaks (DSBs) and they were confirmed by the γ-H2AX assay. Both compounds induced apoptosis and perturbed the cell cycle. Therefore, methacrylic acid, a product of HEMA degradation, may be involved in its cytotoxic and genotoxic action.

  10. Synthesis of magnetic poly(styrene-methacrylic acid) spheres prepared by miniemulsion polymerization

    NASA Astrophysics Data System (ADS)

    Betancourt Galindo, R.; Rodriguez Fernandez, O. S.; Garcia Cerda, L. A.

    2008-12-01

    Magnetic poly(styrene-methacrylic acid), P(St-MAA), spheres were synthesized by miniemulsion polymerization in the presence of a ferrofluid. Magnetite (Fe_{3}O_{4}) nanoparticles obtained by the coprecipitation method, with an average diameter of 14 nm, were used as a magnetic source. A kerosene-based magnetite ferrofluid was mixed with styrene (St) and methacrylic acid (MAA) monomers in the presence of hexadecane as a co-surfactant; sodium dodecil sulphate (SDS) and potassium persulphate (KPS) were used as a surfactant and an initiator, respectively, for a subsequent polymerization. The morphology and properties of the magnetic spheres were studied by TGA, SEM and VSM. The magnetic P(St-MAA) spheres are uniform in shape and size and have diameters less than 150 nm. Magnetization data suggest a superparamagnetic behaviour and a maximum magnetization of 0.22 emu/g. Figs 7, Refs 11.

  11. Experimental and theoretical investigation of the complexation of methacrylic acid and diisopropyl urea

    NASA Astrophysics Data System (ADS)

    Pogány, Peter; Razali, Mayamin; Szekely, Gyorgy

    2017-01-01

    The present paper explores the complexation ability of methacrylic acid which is one of the most abundant functional monomer for the preparation of molecularly imprinted polymers. Host-guest interactions and the mechanism of complex formation between methacrylic acid and potentially genotoxic 1,3-diisopropylurea were investigated in the pre-polymerization solution featuring both experimental (NMR, IR) and in silico density functional theory (DFT) tools. The continuous variation method revealed the presence of higher-order complexes and the appearance of self-association which were both taken into account during the determination of the association constants. The quantum chemical calculations - performed at B3LYP 6-311 ++G(d,p) level with basis set superposition error (BSSE) corrections - are in agreement with the experimental observations, reaffirming the association constants and justifying the validity of computational investigation of such systems. Furthermore, natural bond orbital analysis was carried out to appraise the binding properties of the complexes.

  12. Autonomous healing materials based on epoxidized natural rubber and ethylene methacrylic acid ionomers

    NASA Astrophysics Data System (ADS)

    Arifur Rahman, Md; Penco, Maurizio; Peroni, Isabella; Ramorino, Giorgio; Janszen, Gerardus; Di Landro, Luca

    2012-03-01

    The development of autonomous healing material has an enormous scientific and technological interest. In this context, this research work deals with the investigation of autonomous healing behavior of epoxidized natural rubber (ENR) and its blends with ethylene methacrylic acid ionomers. The autonomous healing behavior of ENR and its blends containing two different ionomers [poly(ethylene-co-methacrylic acid sodium salt) (EMNa) and poly(ethylene-co-methacrylic acid zinc salt) (EMZn)] has been studied by ballistic puncture tests. Interestingly, EMNa/ENR blends exhibit complete healing just after the ballistic test but EMZn/ENR blends do not show full self-repairing. The healing efficiency has been evaluated by optical microscopy and a depressurized air-flow test. The healing mechanism has been investigated by characterizing thermal and mechanical properties of the blends. The chemical structure studied by FTIR and thermal analysis show that the ion content of ionomers and functionality of ENR has a significant influence on the self-healing behavior.

  13. Influence of gelatinization on the extraction of phenolic acids from wheat fractions.

    PubMed

    Lu, Yingjian; Luthria, Devanand

    2016-03-01

    The effect of gelatinization on the analysis of phenolic acids from wheat bran, whole-wheat, and refined flour samples was investigated using two extraction procedures, namely, ultrasonic (UAE) and microwave (MAE). The total phenolic acid (TPA) quantity in wheat bran (2711-2913μg/g) was significantly higher than the whole (664-715μg/g) and refined wheat (109-112μg/g) flour samples by both extraction methods as analyzed by liquid chromatography mass spectrometry. The recovery of phenolic acids from the spiked wheat bran sample was higher than from either the whole or refined wheat flour samples by both extraction procedures. The recovery of TPA (74-89%) from whole and refined wheat flours by MAE was significantly lower than that of UAE (90-98%). This difference was attributed to the gelatinization of starch present in the wheat flours caused by MAE. Gelatinization reduces the extractability of phenolic acids from wheat flour samples. Furthermore, both spectrometric assays (total phenolic content and radical scavenging capacities) showed similar trend as compared to LC-MS analyses. Copyright © 2015. Published by Elsevier Ltd.

  14. Mechanical Characterization of a Dynamic and Tunable Methacrylated Hyaluronic Acid Hydrogel

    PubMed Central

    Ondeck, Matthew G.; Engler, Adam J.

    2016-01-01

    Hyaluronic acid (HA) is a commonly used natural polymer for cell scaffolding. Modification by methacrylate allows it to be polymerized by free radicals via addition of an initiator, e.g., light-sensitive Irgacure, to form a methacrylated hyaluronic acid (MeHA) hydrogel. Light-activated crosslinking can be used to control the degree of polymerization, and sequential polymerization steps allow cells plated onto or in the hydrogel to initially feel a soft and then a stiff matrix. Here, the elastic modulus of MeHA hydrogels was systematically analyzed by atomic force microscopy (AFM) for a number of variables including duration of UV exposure, monomer concentration, and methacrylate functionalization. To determine how cells would respond to a specific two-step polymerization, NIH 3T3 fibroblasts were cultured on the stiffening MeHA hydrogels and found to reorganize their cytoskeleton and spread area upon hydrogel stiffening, consistent with cells originally cultured on substrates of the final elastic modulus. PMID:26746491

  15. Reactive Poly(Amic Acid)/ Poly(Glycidyl Methacrylate-r-Poly(ethylene Glycol) Methyl Ether Methacrylate) Blends as Gas Permeation Membranes

    NASA Astrophysics Data System (ADS)

    Beaulieu, Michael; Watkins, James

    2012-02-01

    Polymers containing polar moieties, such as ether groups show an affinity for acidic gases, such as CO2 due to dipole-quadrapole interactions. Polymer blends in which one of the components is poly(ethylene glycol) (PEG) have been studied extensively in literature as a CO2/light gas permeation membrane, but due to the crystallization and poor mechanical properties have been difficult to incorporate PEG above 60wt%. In this study, a series of random copolymers containing both glycidyl methacrylate and poly(ethylene glycol) methyl ether methacrylate in different ratios are blended with a poly(amic acid) prepolymer made from 4, 4'-oxydianiline and pyromellitic dianhydride to create gas permeation membranes. By using a reactive blend PEG loadings above 70% have been realized with sufficient mechanical properties, and since the side chain on the PEGMA is short these blends do not suffer from crystallization.

  16. Cold water fish gelatin modification by a natural phenolic cross-linker (ferulic acid and caffeic acid)

    PubMed Central

    Araghi, Maryam; Moslehi, Zeinab; Mohammadi Nafchi, Abdorreza; Mostahsan, Amir; Salamat, Nima; Daraei Garmakhany, Amir

    2015-01-01

    Nowadays use of edible films and coatings is increasing due to their biodegradability and environment friendly properties. Fish gelatin obtained from fish skin wastage can be used as an appropriate protein compound for replacing pork gelatin to produce edible film. In this study films were prepared by combination of fish gelatin and different concentration (0%, 1%, 3%, and 5%) of two phenolic compounds (caffeic acid and ferulic acid). The film was prepared at pH > 10 and temperature of 60˚c under continuous injection of O2 and addition of the plasticizer sorbitol/glycerol. Results showed that solubility, oxygen permeability, and water vapor permeability were decreased for caffeic acid and the highest effect was observed at concentration of 5%. Solubility had a linear relationship with concentration of phenolic compound in film containing ferulic acid, however, no significant change was observed in vapor and O2 permeability. A comparison between two phenolic compounds showed that caffeic acid had the highest effect in decreasing solubility, water vapor permeability, and oxygen permeability. Caffeic acid is more effective phenolic compound compared with Ferulic acid that can increase safety of biodegradable packaging by improving their barrier and physicochemical properties. PMID:26405523

  17. Effect of phospholipids transesterified enzymatically with polyunsaturated fatty acids on gelatinization and retrogradation of starch.

    PubMed

    Siswoyo, L A; Morita, N

    2000-10-01

    The effects of phospholipids (PLs) transesterified with polyunsaturated fatty acids (PUFAs) with lipase (Aspergillus niger) on gelatinization and retrogradation of starch during storage were studied by differential scanning calorimetry (DSC). The resulting transesterified PLs were rich in PUFAs and linoleic acid, while the total percentage of PUFAs incorporated was 20.2%. The addition of PLs or PLs enzymatically transesterified with PUFAs (PUFA-PLs) to the starch sample decreased the gelatinization enthalpy of starch (deltah(g)) slightly, but clearly increased the starch-lipid complexes (deltah(s-1)) by DSC. After 21 days of storage, the percent of retrogradation of starch became lower by the addition of 4%, PLs or 4% PUFA-PLs to the starch sample when compared with the control. These results suggest that PLs retard retrogradation of starch during storage, whereas PUFA-PLs retard it greatly. The addition of PLs or PUFA-PLs increased the amount of deltah(s-1), while re-gelatinization enthalpy decreased during storage, which suggests that PLs or PUFA-PLs could retard the retrogradation of starch.

  18. Molecularly imprinted films of acrylonitrile/methyl methacrylate/acrylic acid terpolymers: influence of methyl methacrylate in the binding performance of L-ephedrine imprinted films.

    PubMed

    Brisbane, Carrie; McCluskey, Adam; Bowyer, Michael; Holdsworth, Clovia I

    2013-05-07

    Molecularly imprinted polymeric films (MIPFs) highly selective to 1R,2S(-)ephedrine (L-ephedrine, EPD) were produced by phase inversion post-polymerization imprinting on poly(acrylonitrile-co-methyl methacrylate-co-acrylic acid) (PAMA) terpolymers. The inclusion of methyl methacrylate (MMA) to the polymer formulation resulted in enhanced EPD selectivity which appears to be dictated by polymer composition to achieve the necessary balance between polymer rigidity and porosity. Substitution of MMA with methyl acrylate, ethyl acrylate and n-butyl acrylate resulted in a loss of EPD selectivity and EPD entrapment within the polymer matrix not observed in PAMA MIPFs. MMA, by virtue of its methyl group, is able to provide the scaffolding and rigidity necessary for stability and preservation of imprinted cavities within the PAMA MIPF leading to high EPD selectivity.

  19. Moleculary imprinted polymers with metalloporphyrin-based molecular recognition sites coassembled with methacrylic acid.

    PubMed

    Takeuchi, T; Mukawa, T; Matsui, J; Higashi, M; Shimizu, K D

    2001-08-15

    A diastereoselective molecularly imprinted polymer (MIP) for (-)-cinchonidine, PPM(CD), was prepared by the combined use of methacrylic acid and vinyl-substituted zinc(II) porphyrin as functional monomers. Compared to MIPs using only methacrylic acid or zinc porphyrin as a functional monomer, PM(CD) and PP(CD), respectively, PPM(CD) showed higher binding ability for (-)-cinchonidine in chromatographic tests using the MIP-packed columns. Scatchard analysis gave a higher association constant of PPM(CD) for (-)-cinchonidine (1.14 x 10(7) M(-1)) than those of PP(CD) (1.45 x 10(6) M(-1)) and PM(CD) (6.78 x 10(6) M(-1)). The affinity distribution of binding sites estimated by affinity spectrum analysis showed a higher percentage of high-affinity sites and a lower percentage of low-affinity sites in PPM(CD). The MIPs containing a zinc(II) porphyrin in the binding sites, PPM(CD) and PP(CD), showed fluorescence quenching according to the binding of (-)-cinchonidine, and the quenching was significant in the low-concentration range, suggesting that the high-affinity binding sites contain the porphyrin residue. The correlation of the relative fluorescence intensity against log of (-)-cinchonidine concentrations showed a linear relationship. These results revealed that the MIP having highly specific binding sites was assembled by the two functional monomers, vinyl-substituted zinc(II) porphyrin and methacrylic acid, and they cooperatively worked to yield the specific binding. In addition, the zinc(II) porphyrin-based MIPs appeared to act as fluorescence sensor selectively responded by binding events of the template molecule.

  20. Poly(acrylic acid-co-methyl methacrylate)/metronidazole systems: synthesis and complexation.

    PubMed

    Bialik-Wąs, Katarzyna; Pielichowski, Krzysztof

    2013-01-01

    We report on preparation of poly(acrylic acid-co-methyl methacrylate) (PAM) micro- and nanoparticles and, in the subsequent stage, complexation reaction with the active substance - metronidazole (MET). The drug release behavior of MET - loaded PAM micro- and nanoparticles was evaluated in water and phosphate buffered saline (PBS, 0.9% NaCl) at 37ºC. It has been found that introduction of MET into PAM micro- and nanoparticles enabled gradual and controlled release of the active substance. Structural analysis using FT-IR (ATR) and (1)H NMR, as well as surface morphology assessment by SEM, were performed.

  1. Fabrication of poly (L-lactic acid)/gelatin composite tubular scaffolds for vascular tissue engineering.

    PubMed

    Shalumon, K T; Deepthi, S; Anupama, M S; Nair, S V; Jayakumar, R; Chennazhi, K P

    2015-01-01

    The in vitro fabrication of fully functional 3D vascular tissue construct represents one of the most fundamental challenges in vascular tissue engineering. Polymer blending is an effective method for developing, desirable bio-composites for tissue engineering. This study employs the blending of desired characteristics of a synthetic polymer, poly (L-lactic acid) (PLLA) and a biopolymer, gelatin for enhancing cell adhesion sites. Aligned and random PLLA/gelatin nanofibers were fabricated using electrospinning technique. Morphological and chemical characterization of the nanofibrous scaffolds was carried out and the size of fibers ranged from 100 to 500 nm. The SEM, fluorescent staining and viability assays revealed an increase in viability and proliferation of Human Umbilical Vein Endothelial Cells (HUVECs) and Smooth Muscle Cells (SMCs) proportional to gelatin content. The aligned fiber morphology helps cells to orient and elongate along their long axis. Thus the results were suggestive of the fact that topographically aligned nanofibrous scaffolds control cellular organization and possibly provide a good support for achieving the vital organization and physical properties of blood vessel.

  2. Fabrication of gelatin-hyaluronic acid hybrid scaffolds with tunable porous structures for soft tissue engineering.

    PubMed

    Zhang, Fan; He, Chuanglong; Cao, Lijun; Feng, Wei; Wang, Hongsheng; Mo, Xiumei; Wang, Jinwu

    2011-04-01

    The development of three-dimensional (3-D) scaffolds with highly open porous structure is one of the most important issues in tissue engineering. In this study, 3-D macroporous gelatin/hyaluronic acid (GE/HA) hybrid scaffolds with varying porous morphology were prepared by freeze-drying their blending solutions and subsequent chemical crosslinking by using 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDC). The resulting scaffolds were characterized by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). Their swelling, in vitro degradation properties and compressive strength were also investigated. To evaluate in vitro cytocompatibility of scaffolds, mouse L929 fibroblasts were seeded onto the scaffolds for cell morphology and cell viability studies. It was found that the porous structure of scaffolds can be tailored by varying the ratios of gelatin to HA, both the swelling ratios and degradation rate increased with the increase of HA content in hybrid scaffolds, and crosslinking the scaffolds with EDC improved the degradation resistance of the scaffold in culture media and increased the mechanical strength of scaffolds. The in vitro results revealed that the prepared scaffolds do not induce cytotoxic effects and suitable for cell growth, especially in the case of scaffolds with higher gelatin content. The combined results of the physicochemical and biological studies suggested that the developed GE/HA hybrid scaffolds exhibit good potential and biocompatibility for soft tissue engineering applications. Copyright © 2011 Elsevier B.V. All rights reserved.

  3. Photoinduced graft-copolymer synthesis and characterization of methacrylic acid onto natural biodegradable lignocellulose fiber.

    PubMed

    Khan, Ferdous

    2004-01-01

    UV radiation induced graft copolymerization of methacrylic acid onto natural lignocellulose (jute) fiber was carried out both by "simultaneous irradiation and grafting" and by preirradiation methods using 1-hydroxycyclohexyl-phenyl ketone as a photoinitiator. In the "simultaneous irradiation and grafting" method, the variation of graft weight with UV-radiation time, monomer concentration, and the concentration of photoinitiator was investigated. In the case of the preirradiation method, the incorporation of 2-methyl-2-propene 1-sulfonic acid, sodium salt, into the grafting reaction solution played a most important role in suppressing the homopolymer/gel formation and facilitating graft copolymerization. The optimum value of the reaction parameters on the percentage of grafting was evaluated. In comparison, results showed that the method of graft-copolymer synthesis has significant influence on graft weight. The study on the mechanical and thermal properties of grafted samples was conducted. The results showed that the percentage of grafting has a significant effect on the mechanical and thermal properties in the case of grafted samples. Considering the water absorption property, the jute-poly(methacrylic acid)-grafted sample showed a maximum up to 42% increase in hydrophilicity with respect to that of the "as received" sample. Attenuated total reflection infrared studies indicate that the estimation of the degree of grafting could be achieved by correlating band intensities with the percent graft weight.

  4. Effects of metal ions on entero-soluble poly(methacrylic acid-methyl methacrylate) coating: a combined analysis by ATR-FTIR spectroscopy and computational approaches.

    PubMed

    Cilurzo, Francesco; Gennari, Chiara G M; Selmin, Francesca; Vistoli, Giulio

    2010-04-05

    Poly(methacrylic acid-methyl methacrylate)s (HPMMs) are pH-dependent polymers which ionize and form salts (PMMs) in neutral conditions. Despite their wide use in tablet coating, the interactions of PMMs with electrolytes present in biorelevant media and luminal fluids have been scantly investigated. The data generated in the current work provide the basic information on the effect of bivalent cations, namely, Ca2+, Zn2+ and Mn2+, on the HPMMs' solubility and, consequently, on the performances (disintegration and drug dissolution) of acetaminophen gastroresistant tablets when exposed to fluid containing such salts. The interactions between polymers and metal ions were analyzed by ATR-FTIR spectroscopy and in silico combining molecular dynamics simulations to explore the conformational profiles of several oligomers with different M(w), taken as model of the polymers, with ab initio and semiempirical calculations in the gas phase. The computational results agree with the experimental data in terms of spatial disposition of the bications with respect to PMMs (Ca2+ and Mn2+ as bidentate form and Zn2+ as monodentate ligand) and interaction strength (Zn2+ > Mn(2+) > Ca2+). The tablet disintegration and dissolution rate of acetaminophen were strongly affected by the interactions of the dissolving copolymer with the metal ions which led to coating insolubilization. These preliminary results underline that the ingestion of metal ions at high concentrations could affect the drug liberation from gastroresistant dosage forms.

  5. Entrapment of methyl parathion hydrolase in cross-linked poly(γ-glutamic acid)/gelatin hydrogel.

    PubMed

    Xie, Jianfei; Zhang, Huiwen; Li, Xu; Shi, Yuanliang

    2014-02-10

    Methyl parathion hydrolase (MPH) is an important enzyme in hydrolyzing toxic organophosphorus (OP) compounds. However, MPH is easily deactivated when subjected to extreme environmental conditions and is difficult to recover from the reaction system for reuse, thereby limiting its practical application. To address these shortcomings, we examined the entrapment of MPH in an environment-friendly, biocompatible and biodegradable cross-linked poly(γ-glutamic acid)/gelatin hydrogel. The cross-linked poly(γ-glutamic acid)/gelatin hydrogels were prepared with different gelatin/poly(γ-glutamic acid) mass ratios using water-soluble carbodiimide as the cross-linking agent. The MPH-entrapped cross-linked poly(γ-glutamic acid)/gelatin hydrogel (CPE-MPH) not only possessed improved thermostability, pH stability, and reusability but also exhibited enhanced efficiency in hydrolyzing OP compounds. Furthermore, CPE-MPH possesses high water-absorbing and water-retaining capabilities. We believe that the cross-linked poly(γ-glutamic acid)/gelatin hydrogels are an attractive carrier for the entrapment of diverse enzymes, affording a new approach for enzyme entrapment.

  6. Morphological Determinants of Yield Stress for Semicrystalline Ethylene / Methacrylic Acid Copolymers

    NASA Astrophysics Data System (ADS)

    Scogna, Robert; Register, Richard

    2008-03-01

    Reducing the crystal thickness of ethylene/α-olefin copolymers typically results in a decrease in the measured yield stress. However, statistical incorporation of methacrylic acid, also a noncrystallizable comonomer, actually increases the yield stress at room temperature. The yield stress for ethylene/methacrylic acid (E/MAA) copolymers as a function of temperature and test rate is described using a model which accounts for polyethylene crystal plasticity through thermal nucleation of screw dislocations in addition to the effects of incomplete relaxation of the amorphous fraction at the strain rate employed. This is possible using a small number of physically reasonable best-fit parameters. Yield stress master curves can be constructed for any material that obeys the model; such curves have been constructed for a low-density polyethylene and five copolymers of varying MAA content from data taken at various strain rates and temperatures. The master curves clearly show that this unusual behavior of the yield stress is caused by the increase in β relaxation temperature with increasing MAA content, as seen via dynamic mechanical testing.

  7. pH-responsive poly(methacrylic acid)-grafted hollow silica vesicles.

    PubMed

    Lay, Chee Leng; Tan, Hui Ru; Lu, Xuehong; Liu, Ye

    2011-02-18

    Poly(methacrylic acid)-grafted hollow silica vesicles (PMAA-g-hollow silica vesicles) were obtained through a grafting-from approach. PMAA brushes were formed by performing atom-transfer radical polymerisation of sodium methacrylate with an initiator attached to the hollow silica spheres. PMAA-g-hollow silica vesicles were characterised by using TEM, thermogravimetric analysis (TGA) and FTIR spectroscopy. pH-dependent ξ potential and (1)H NMR spectra of PMAA-g-hollow silica vesicles were measured, and the results indicated that MAA brushes in PMAA-g-hollow silica vesicles had a lower ionisation degree and low solubility in acidic aqueous solution, for example, pH 3.4, but a higher ionisation degree and high solubility when the pH was higher than 7. Also it was demonstrated that calcein blue and fluorescein isothiocyanate (FITC) labelled dextran (M(n):10 kDa) could be encapsulated in the interiors of the PMAA-g-hollow silica vesicles with a negligible amount in PMAA brushes at pH 2, and pH-triggered release of calcein blue and FITC-labelled dextran from PMAA-g-hollow silica vesicles was observed at pH 7.4. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Synthesis and characterization of hydrolysed starch-g-poly(methacrylic acid) composite.

    PubMed

    Zahran, Magdy K; Ahmed, Enas M; El-Rafie, Mohamed H

    2016-06-01

    A novel method for the synthesis of starch-g-poly(methacrylic acid) composite was adopted by graft polymerization of hydrolysed starch (HS) and methacrylic acid (MAA) in aqueous medium using an efficient sodium perborate (SPB)-thiourea (TU) redox initiation system. The parameters influencing the redox system efficiency and thence the polymerization method were considered. These parameters comprehended the concentrations of MAA, SPB, TU and SPB/TU molar ratio as well as the polymerization temperature. The polymerization reaction was scrutinized through calculation of the MAA total conversion percent (TC%). The resultant poly(MAA-HS) composite was assessed by evaluating the polymer criteria (the graft yield, GY%; the grafting efficiency, GE%; the homopolymer, HP%; and the total conversion). The comportment of the apparent viscosity of the cooked poly(MAA)-starch composite paste, obtained under diverse polymerization conditions, was examined. Tentative mechanisms, which depict all occasions that happen amid the entire course of the polymerization reaction, have been proffered. Copyright © 2016 Elsevier B.V. All rights reserved.

  9. Evaluation and biological characterization of bilayer gelatin/chondroitin-6-sulphate/hyaluronic acid membrane.

    PubMed

    Wang, Tzu-Wei; Sun, Jui-Sheng; Wu, Hsi-Chin; Huang, Yi-Chau; Lin, Feng-Huei

    2007-08-01

    A biodegradable polymer scaffold was developed using gelatin, chondroitin-6-sulphate, and hyaluronic acid in the form of bilayer network. The bilayer porous structure of gelatin-chondroitin-6-sulphate-hyaluronic acid (G-C6S-HA) membrane was fabricated using different freezing temperatures followed by lyophilization. 1-Ethyl-3(3-dimethylaminopropyl) carbodiimide was used as crosslinking agent to improve the biological stability of the scaffold. The morphology, physical-chemical properties, and biocompatibility of bilayer G-C6S-HA membrane were evaluated in this study. The functional groups change in crosslinked G-C6S-HA scaffold was characterized by fourier transform infrared spectroscopy. The retention of glycosaminoglycan contents and matrix degradation rate were also examined by p-dimethylamino benzaldehyde and 2,4,6-trinitrobenzene sulphonic acid, respectively. Water absorption capacity was carried out to study G-C6S-HA membrane water containing characteristics. The morphology of the bilayer G-C6S-HA membrane was investigated under scanning electron microscope and light microscopy. In vitro biocompatibility was conducted with MTT test, LDH assay, as well as histological analysis. The results showed that the morphology of bilayer G-C6S-HA membrane was well reserved. The physical-chemical properties were also adequate. With good biocompatibility, this bilayer G-C6S-HA membrane would be suitable as a matrix in the application of tissue engineering.

  10. The synthesis, properties, and applications of hydrophilic polymers and copolymers of hydroxyalkyl esters of acrylic and methacrylic acids

    NASA Astrophysics Data System (ADS)

    Asadov, Z. G.; Aliev, V. S.

    1992-05-01

    The scientific-technical and patent literature on the synthesis of hydroxyalkyl esters of acrylic and methacrylic acids by their catalytic reaction with epoxyalkanes, by the radical copolymerisation and polymerisation of presynthesised monomeric esters, and also by the chemical modification of polymerisation and copolymerisation products is surveyed. A wide variety of physicochemical properties of the polymers and copolymers based on the hydroxyalkyl esters of acrylic and methacrylic acids are described. The principal trends and prospects in the application of the high-molecular-weight products obtained in various branches of the national economy are indicated. The bibliography includes 158 references.

  11. Synthesis of [.sup.13C] and [.sup.2H] substituted methacrylic acid, [.sup.13C] and [.sup.2H] substituted methyl methacrylate and/or related compounds

    DOEpatents

    Alvarez, Marc A.; Martinez, Rodolfo A.; Unkefer, Clifford J.

    2008-01-22

    The present invention is directed to labeled compounds of the formulae ##STR00001## wherein Q is selected from the group consisting of --S--, --S(.dbd.O)--, and --S(.dbd.O).sub.2--, Z is selected from the group consisting of 1-naphthyl, substituted 1-naphthyl, 2-naphthyl, substituted 2-naphthyl, and phenyl groups with the structure ##STR00002## wherein R.sub.1, R.sub.2, R.sub.3, R.sub.4 and R.sub.5 are each independently selected from the group consisting of hydrogen, a C.sub.1-C.sub.4 lower alkyl, a halogen, and an amino group selected from the group consisting of NH.sub.2, NHR and NRR' where R and R' are each independently selected from the group consisting of a C.sub.1-C.sub.4 lower alkyl, an aryl, and an alkoxy group, and X is selected from the group consisting of hydrogen, a C.sub.1-C.sub.4 lower alkyl group, and a fully-deuterated C.sub.1-C.sub.4 lower alkyl group. The present invention is also directed to a process of preparing labeled compounds, e.g., process of preparing [.sup.13C]methacrylic acid by reacting a (CH.sub.3CH.sub.2O--.sup.13C(O)--.sup.13CH.sub.2)-- aryl sulfone precursor with .sup.13CHI to form a (CH.sub.3CH.sub.2O--.sup.13C(O)--.sup.13C(.sup.13CH.sub.3).sub.2)-- aryl sulfone intermediate, and, reacting the (CH.sub.3CH.sub.2O--.sup.13C(O)--.sup.13C(.sup.13CH.sub.3).sub.2)-- aryl sulfone intermediate with sodium hydroxide, followed by acid to form [.sup.13C]methacrylic acid. The present invention is further directed to a process of preparing [.sup.2H.sub.8]methyl methacrylate by reacting a (HOOC--C(C.sup.2H.sub.3).sub.2-- aryl sulfinyl intermediate with CD.sub.3I to form a (.sup.2H.sub.3COOC--C(C.sup.2H.sub.3).sub.2)-- aryl sulfinyl intermediate, and heating the(.sup.2H.sub.3COOC--C(C.sup.2H.sub.3).sub.2)-- aryl sulfinyl intermediate at temperatures and for time sufficient to form [.sup.2H.sub.8]methyl methacrylate.

  12. Synthesis and characterization of anionic amphiphilic model conetworks of 2-butyl-1-octyl-methacrylate and methacrylic acid: effects of polymer composition and architecture.

    PubMed

    Kali, Gergely; Georgiou, Theoni K; Iván, Béla; Patrickios, Costas S; Loizou, Elena; Thomann, Yi; Tiller, Joerg C

    2007-10-09

    Seven amphiphilic conetworks of methacrylic acid (MAA) and a new hydrophobic monomer, 2-butyl-1-octyl-methacrylate (BOMA), were synthesized using group transfer polymerization. The MAA units were introduced via the polymerization of tetrahydropyranyl methacrylate (THPMA) followed by the removal of the protecting tetrahydropyranyl group by acid hydrolysis after network formation. Both THPMA and BOMA were in-house synthesized. Ethylene glycol dimethacrylate (EGDMA) was used as the cross-linker. Six of the conetworks were model conetworks, containing copolymer chains between cross-links of precise molecular weight and composition. The prepared conetwork series covered a wide range of compositions and architectures. In particular, the MAA content was varied from 67 to 94 mol %, and three different conetwork architectures were constructed: ABA triblock copolymer-based, statistical copolymer-based, and randomly cross-linked. The linear conetwork precursors were analyzed by gel permeation chromatography and 1H NMR spectroscopy in terms of their molecular weight and composition, both of which were found to be close to the theoretically calculated values. The degrees of swelling (DS) of all the amphiphilic conetworks were measured in water and in THF over the whole range of ionization of the MAA units. The DSs in water increased with the degree of ionization (DI) and the content of the hydrophilic MAA units in the conetwork, while the DSs in THF increased with the degree of polymerization of the chains between the cross-links and by reducing the DI of the MAA units. Finally, the nanophase behavior of the conetworks was probed using small-angle neutron scattering and atomic force microscopy.

  13. Pulsed electromembrane extraction for analysis of derivatized amino acids: A powerful technique for determination of animal source of gelatin samples.

    PubMed

    Rezazadeh, Maryam; Yamini, Yadollah; Seidi, Shahram; Aghaei, Ali

    2015-05-01

    Differentiation of animal sources of gelatin is required for many reasons such as some anxieties about bovine spongiform encephalopathy or a ban on consuming porcine gelatin in some religions. In the present work, an efficient method is introduced for determination of animal origin of gelatin samples. The basis of this procedure is the application of pulsed electric field for extraction, preconcentration, and analysis of derivatized amino acids in gelatin. To this end, after derivatization of amino acids of interest by means of o-phthalaldehyde (OPA) for enhancing their ultraviolet (UV) absorbance as well as increasing their lipophilicities, a 137V electric field was applied for 20min with 10min(-1) frequency to make the analytes migrate through a 200µm organic liquid membrane into an aqueous acceptor phase. Finally, the acceptor phase was analyzed by HPLC-UV. The proposed technique offered a high efficiency for analysis of amino acids, regarding 43% and 79% as extraction recoveries and 25ng mL(-1) and 50ng mL(-1) as limits of detection (LODs) for asparagine and glutamine, respectively. Therefore, due to sample cleanup ability of the proposed method and obtained preconcentration factors (29 and 53 for asparagine and glutamine, respectively), it could be carried out for differentiation of animal origins of gelatin samples, even if only small amounts of samples are available or in complicated media of foodstuffs and medicament. Copyright © 2015 Elsevier B.V. All rights reserved.

  14. Use of Methacrylic Acid-Containing Hydrogels to Increase Protein Transport Across the Intestinal Epithelium

    NASA Astrophysics Data System (ADS)

    Blanchette, James; Lopez, Jennifer; Park, Kinam; Peppas, Nicholas

    2002-03-01

    Oral protein delivery requires protection from the harsh environment of the stomach, release in the small intestine and passage from the intestinal lumen into the circulation. Hydrogels that swell in response to the pH change when passing from the stomach to the small intestine can accomplish the first two points. The ability to enhance the permeability of intestinal epithelial cells is currently under investigation. Methacrylic acid-containing hydrogels have shown the ability to bind calcium ions that decreases the concentration of free extracellular calcium for these epithelial cells. This change triggers a number of intracellular events including rearrangement of the cytoskeleton leading to increased permeability. Studies done on Caco-2 cells (human colon adenocarcinoma) measuring changes in transepithelial resistance are used to assess the effect of the polymer-cell interactions on the integrity of intestinal epithelial cell monolayers.

  15. Acoustic and ultrasonic characterization constraints of self-healing (ethylene-co-methacrylic acid) copolymers

    NASA Astrophysics Data System (ADS)

    Pestka, Kenneth, II; Buckley, Jonathan; Kalista, Stephen; Bowers, Nicholas

    Recent experiments indicate that small sample poly (ethylene-co-methacrylic acid) copolymers (EMAA copolymers) exhibit time dependent variation in their acoustic and ultrasonic resonant spectra after exposure to a damage event. However, due to the relatively soft nature of these thermoplastic materials, several experimental constraints affect efficacy of resonant spectral analysis. In this work we will the address the effect of several characterization constraints on a self-healing EMAA ionomer (commercially known as Dupont Surlyn 8920) including the effects of transducer loading, continuous rapid resonant excitation and temporally separated long-term resonant excitation. In some circumstances, these experimental constraints can influence the time dependence of sample resonant frequency evolution, quality factor, and variation in spectral waveform. By quantifying these effects, robust characterization of post-damage self-healing EMAA samples is possible and will be presented.

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

    PubMed

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

    2011-01-01

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

  17. New Poly(amino acid methacrylate) Brush Supports the Formation of Well-Defined Lipid Membranes

    PubMed Central

    2015-01-01

    A novel poly(amino acid methacrylate) brush comprising zwitterionic cysteine groups (PCysMA) was utilized as a support for lipid bilayers. The polymer brush provides a 12-nm-thick cushion between the underlying hard support and the aqueous phase. At neutral pH, the zeta potential of the PCysMA brush was ∼−10 mV. Cationic vesicles containing >25% DOTAP were found to form a homogeneous lipid bilayer, as determined by a combination of surface analytical techniques. The lipid mobility as measured by FRAP (fluorescence recovery after photobleaching) gave diffusion coefficients of ∼1.5 μm2 s–1, which are comparable to those observed for lipid bilayers on glass substrates. PMID:25746444

  18. The Competing Effects of Hyaluronic and Methacrylic Acid in Model Contact Lenses.

    PubMed

    Weeks, Andrea; Subbaraman, Lakshman N; Jones, Lyndon; Sheardown, Heather

    2012-01-01

    The aim of this study was to determine the influence of hyaluronic acid (HA) on lysozyme sorption in model contact lenses containing varying amounts of methacrylic acid (MAA). One model conventional hydrogel (poly(2-hydroxyethyl methacrylate) (pHEMA)) and two model silicone hydrogels (pHEMA, methacryloxypropyltris(trimethylsiloxy)silane (pHEMA TRIS) and N,N-dimethylacrylamide, TRIS (DMAA TRIS)) lens materials were prepared with and without MAA at two different concentrations (1.7 and 5%). HA, along with dendrimers, was loaded into these model contact lens materials and then cross-linked with 1-ethyl-3-(3-dimethylamino propyl)-carbodiimide (EDC). Equilibrium water content (EWC), advancing water contact angle and lysozyme sorption on these lens materials were investigated. In the HA-containing materials, the presence (P < 0.05) and amount (P < 0.05) of MAA increased the EWC of the materials. For most materials, addition of MAA reduced the advancing contact angles (P < 0.05) and for all the materials, the addition of HA further improved hydrophilicity (P < 0.05). For the non-HA containing hydrogels, the presence (P < 0.05) and amount (P < 0.05) of MAA increased lysozyme sorption. The presence of HA decreased lysozyme sorption for all materials (P < 0.05). MAA appears to work synergistically with HA to increase the EWC in addition to improving the hydrophilicity of model pHEMA-based and silicone hydrogel contact lens materials. Hydrogel materials that contain HA have tremendous potential as hydrophilic, protein-resistant contact lens materials.

  19. Oleic Acid Coated Gelatin Nanoparticles Impregnated Gel for Sustained Delivery of Zaltoprofen: Formulation and Textural Characterization

    PubMed Central

    Pawar, Savita; Pande, Vishal

    2015-01-01

    Purpose: In the present study, we have formulated zaltoprofen loaded, surface decorated, biodegradable gelatin nanogel and evaluated its texture characterization. Methods: The method used to prepare gelatin nanoparticles (GNP) was ‘two step desolvation’ and its surface decoration was performed with oleic acid (OA). The GNP was optimized by DOE software. Nanogels were evaluated for particle size entrapment efficiency, texture properties, SEM, in-vitro, ex-vivo drug release studies, in-vitro characterization, stability and in vivo evaluation of nanogel for anti-inflammatory activity was carried out by carrageenan induced rat paw edema method as an anti-inflammatory experimental model. Results: The formulated GNP with particle size and entrapment efficiency of optimized batch was found to be 247.1 nm and 76.21% respectively. The SEM of GNP shows smooth and spherical shape. In-vitro and Ex-vivo drug release shows that there was 69.47% and 78.59% drug released within 48 hrs. It follows Ritger peppas model, which indicates sustained drug release. The good texture properties of nanogel were observed from texture analysis graphs.In vivo studies of our formulation give significant results compared to the marketed nanogel. Stability data revealed stability of nanogel formulation up to 3 months. Conclusion: The present approach can provide us promising results of the sustained analgesic activity and the stability of drug within the GNP. PMID:26819927

  20. Preparation and characterization of pH-sensitive and antifouling poly(vinylidene fluoride) microfiltration membranes blended with poly(methyl methacrylate-2-hydroxyethyl methacrylate-acrylic acid).

    PubMed

    Ju, Junping; Wang, Chao; Wang, Tingmei; Wang, Qihua

    2014-11-15

    Functional terpolymer of poly(methyl methacrylate-2-hydroxyethyl methacrylate-acrylic acid) (P(MMA-HEMA-AA)) was synthesized via a radical polymerization method. The terpolymer could be directly blended with poly(vinylidene fluoride) (PVDF) to prepare the microfiltration (MF) membranes via phase separate process. The synthesized polymers were characterized by Fourier transform infrared (FTIR), the nuclear magnetic resonance proton spectra ((1)H NMR). The membrane had the typical asymmetric structure and the hydrophilic side chains tended to aggregate on the membrane surface. The surface enrichment of amphiphilic copolymer and morphology of MF membranes were characterized by Fourier transform infrared attenuated total reflection spectroscopy (FTIR-ATR) and scanning electron microscopy (SEM). The contact angle (CA) and water uptake were also tested to assess the hydrophilicity and wetting characteristics of the polymer surface. The water filtration properties were measured. It was found the modified membranes showed excellent pH-sensitivity and pH-reversibility behavior. Furthermore, the hydrophilicity of the blended membranes increased, and the membranes showed good protein antifouling property. Copyright © 2014 Elsevier Inc. All rights reserved.

  1. Cisplatin-incorporated nanoparticles of poly(acrylic acid-co-methyl methacrylate) copolymer.

    PubMed

    Lee, Kyung Dong; Jeong, Young-Il; Kim, Da Hye; Lim, Gyun-Taek; Choi, Ki-Choon

    2013-01-01

    Although cisplatin is extensively used in the clinical field, its intrinsic toxicity limits its clinical use. We investigated nanoparticle formations of poly(acrylic acid-co-methyl methacrylate) (PAA-MMA) incorporating cisplatin and their antitumor activity in vitro and in vivo. Cisplatin-incorporated nanoparticles were prepared through the ion-complex formation between acrylic acid and cisplatin. The anticancer activity of cisplatin-incorporated nanoparticles was assessed with CT26 colorectal carcinoma cells. Cisplatin-incorporated nanoparticles have small particle sizes of less than 200 nm with spherical shapes. Drug content was increased according to the increase of the feeding amount of cisplatin and acrylic acid content in the copolymer. The higher acrylic acid content in the copolymer induced increase of particle size and decrease of zeta potential. Cisplatin-incorporated nanoparticles showed a similar growth-inhibitory effect against CT26 tumor cells in vitro. However, cisplatin-incorporated nanoparticles showed improved antitumor activity against an animal tumor xenograft model. We suggest that PAA-MMA nanoparticles incorporating cisplatin are promising carriers for an antitumor drug-delivery system.

  2. Extraction and characterization of gelatin from the feet of Pekin duck (Anas platyrhynchos domestica) as affected by acid, alkaline, and enzyme pretreatment.

    PubMed

    Abedinia, Ahmadreza; Ariffin, Fazilah; Huda, Nurul; Nafchi, Abdorreza Mohammadi

    2017-05-01

    The effects of different pretreatments on yield and composition of extraction, physicochemical, and rheological properties of duck feet gelatin (DFG) were investigated. Gelatins were extracted from the whole feet of Pekin duck with an average yield of 4.09%, 3.65%, and 5.75% for acidic (Ac-DFG), alkaline (Al-DFG), and enzymatic (En-DFG) pretreatment on a wet weight basis, respectively. Proteins at 81.38%, 79.41%, 82.55%, and 87.38% were the major composition for Ac-DFG, Al-DFG, En-DFG, and bovine, respectively. Amino acid analysis showed glycine as the predominant amino acid in Ac-DFG, followed by hydroxyproline, proline, and alanine for Ac-DFG, Al-DFG, and En-DFG, respectively. Rheological analysis indicated that the maximum elastic modulus (9972.25Pa) and loss modulus (4956.28Pa) for Ac-DFG gelatin were significantly higher than those of other gelatins. Extracted gelatins contained α1 and α2 chains as the predominant components, and enzymatic gelatin had low molecular weight peptides. Fourier transform infrared spectroscopy showed that the peak of the gelatins was mainly positioned in the amide band region (amides I, II, and III). A considerable loss of molecular-order triple helical structure was also observed after pepsin treatment. In summary, duck feet gelatin has potential to replace as mammalian gelatin in food and pharmaceutical industry. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Acrylates and Methacrylates,

    DTIC Science & Technology

    1987-09-15

    of ethylene and hydrocyanic acid through ethylene cyanohydrin. In the presence of basic catalysts ethylene oxide easily adds hydrocyanic acid with the...of synthesis of methacrylates. At present methacrylates are obtained in the industry by continuous method from acetone and hydrocyanic acid through...acetone cyanohydrin. The addition/connection to it of hydrocyanic acid with the formation of acetone cyanohydrin is one of the most important reactions

  4. Syntheses and luminescent properties of a copolymer of terbium-p-aminobenzoic acid-methacrylic acid and styrene.

    PubMed

    Zhang, A Q; Yang, Y M; Li, L P; Zhai, G M; Jia, H S; Liu, X G; Xu, B S

    2015-11-01

    A reactive Tb(III) complex with p-aminobenzoic acid (p-ABA) and methacrylic acid (MAA) as ligands was synthesized. A novel copolymer was synthesized by free radical copolymerization of styrene and the reactive Tb(III) complex in dimethyl sulfoxide (DMSO) with 2,2'-azobis(2-methylpropionitrile) (AIBN) as the initiator. IR and UV/Vis spectra indicate that the copolymer exhibited absorption from polystyrene and the complex. Thermogravimetric analysis indicates that the copolymer remained stable up to 357°C and the thermal stability was significantly improved in comparison with polymer matrix and the Tb(III) complex. The luminescent intensity of the synthetic terbium macromolecular complexes increased with increasing complex monomer content. Moreover, concentration quenching was not observed. Copyright © 2015 John Wiley & Sons, Ltd.

  5. Positive mode electrospray tandem mass spectrometry of poly(methacrylic acid) oligomers.

    PubMed

    Giordanengo, Rémi; Viel, Stéphane; Allard-Breton, Béatrice; Thévand, André; Charles, Laurence

    2009-06-01

    The dissociation of small poly(methacrylic acid) (PMAA) cations produced by electrospray was characterized by tandem mass spectrometry. Similarly to PMAA ions produced in the negative ion mode, the two electrosprayed cationic forms, namely [PMAA+Na](+) and [PMAA-H+2Na](+), were shown to fragment via a major pathway consisting of successive dehydration steps. Elimination of a water molecule would occur between two consecutive acid groups in a charged-remote mechanism and was shown to proceed as many times as pairs of acidic pendant groups were available. As a result, comparing the number of dehydration steps observed in the MS/MS spectrum of two consecutive oligomers from the polymeric distribution reveals the degree of polymerization of the molecule. Secondary less informative reactions were shown to consist of losses of CO and/or CO(2), depending on the nature of the precursor ion. These fragmentation rules could be used to characterize PMAA-based copolymers, as successfully demonstrated for a polymeric impurity in the tested PMAA sample.

  6. Preparation and characterisation of Chlorogenic acid-gelatin: A type of biologically active film for coating preservation.

    PubMed

    Fu, Shalu; Wu, Chunhua; Wu, Tiantian; Yu, Haixia; Yang, Shuibing; Hu, Yaqin

    2017-04-15

    Chlorogenic acid (CGA), a type of plant polyphenol, was conjugated onto gelatin (Gel) to prepare a novel coating material for the preservation of fresh seafood. The optimal reaction molar ratio of CGA to gelatin (4:1) was determined according to the CGA content in the CGA-Gel conjugate. CGA was confirmed to be successfully conjugated onto gelatin by (1)H nuclear magnetic resonance and Fourier transform-infrared spectroscopy. The antioxidant activity of CGA-Gel was proven to be higher than that of the free CGA in 2,2'-azinobis-(3-ethylbenzthiazoline-6-sulphonate) radical scavenging, hydrogen peroxide scavenging, ferric ion reducing power and lipid oxidation assays. The minimum inhibitory concentrations (MIC) of CGA against Escherichia coli, Pseudomonas aeruginosa, Listeria monocytogenes and Staphylococcus aureus were 1, 1, 2 and 2mg/mL, respectively. The antibacterial activity of CGA-Gel was unaffected by conjugation. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. Preparation and Characterization of an Olive Flounder (Paralichthys olivaceus) Skin Gelatin and Polylactic Acid Bilayer Film.

    PubMed

    Lee, Ka-Yeon; Song, Kyung Bin

    2017-03-01

    Olive flounder skin gelatin (OSG) was used as a film base material. A bilayer film of OSG and polylactic acid (PLA) was prepared using solvent casting method to enhance the film properties. Physical properties of the OSG-PLA film were increased compared with the nonaugmented OSG film. In particular, the PLA lamination decreased water vapor permeability from 2.17 to 0.92 × 10(-9) g·m/m(2) ·s·Pa, as well as of the water solubility from 16.62% to 9.27%, in the bilayer film relative to the OSG film. The oxygen permeability of the OSG-PLA bilayer film was held low by the OSG film, compensating for the high oxygen permeability of the PLA layer. Therefore, the OSG-PLA bilayer film with its enhanced physical properties and high water and oxygen barrier properties can be applied as a food packaging material.

  8. The profile of adsorbed plasma and serum proteins on methacrylic acid copolymer beads: Effect on complement activation.

    PubMed

    Wells, Laura A; Guo, Hongbo; Emili, Andrew; Sefton, Michael V

    2017-02-01

    Polymer beads made of 45% methacrylic acid co methyl methacrylate (MAA beads) promote vascular regenerative responses in contrast to control materials without methacrylic acid (here polymethyl methacrylate beads, PMMA). In vitro and in vivo studies suggest that MAA copolymers induce differences in macrophage phenotype and polarization and inflammatory responses, presumably due to protein adsorption differences between the beads. To explore differences in protein adsorption in an unbiased manner, we used high resolution shotgun mass spectrometry to identify and compare proteins that adsorb from human plasma or serum onto MAA and PMMA beads. From plasma, MAA beads adsorbed many complement proteins, such as C1q, C4-related proteins and the complement inhibitor factor H, while PMMA adsorbed proteins, such as albumin, C3 and apolipoproteins. Because of the differences in complement protein adsorption, follow-up studies focused on using ELISA to assess complement activation. When incubated in serum, MAA beads generated significantly lower levels of soluble C5b9 and C3a/C3adesarg in comparison to PMMA beads, indicating a decrease in complement activation with MAA beads. The differences in adsorbed protein on the two materials likely alter subsequent cell-material interactions that ultimately result in different host responses and local vascularization.

  9. A simple sonochemical method for fabricating poly(methyl methacrylate)/stearic acid phase change energy storage nanocapsules.

    PubMed

    Wang, Guxia; Xu, Weibing; Hou, Qian; Guo, Shengwei

    2015-11-01

    In this study, stearic acid suitable for thermal energy storage applications was nanoencapsulated in a poly(methyl methacrylate) shell. The nanocapsules were prepared using a simple ultrasonically initiated in situ polymerization method. The morphology and particle size of the poly(methyl methacrylate)/stearic acid phase change energy storage nanocapsules (PMS-PCESNs) were analyzed using transmission electron microscopy, scanning electron microscopy, atomic force microscopy and dynamic light scattering. The latent heat storage capacities of stearic acid and the PMS-PCESNs were determined using differential scanning calorimetry. The chemical composition of the nanocapsules was characterized using Fourier transform infrared spectroscopy. All of the results show that the PMS-PCESNs were synthesized successfully and that the latent heat storage capacity and encapsulation efficiency were 155.6 J/g and 83.0%, respectively, and the diameter of each nanocapsule was 80-90 nm.

  10. Composite Polylactic-Methacrylic Acid Copolymer Nanoparticles for the Delivery of Methotrexate

    PubMed Central

    Sibeko, Bongani; Choonara, Yahya E.; du Toit, Lisa C.; Modi, Girish; Naidoo, Dinesh; Khan, Riaz A.; Kumar, Pradeep; Ndesendo, Valence M. K.; Iyuke, Sunny E.; Pillay, Viness

    2012-01-01

    The purpose of this study was to develop poly(lactic acid)-methacrylic acid copolymeric nanoparticles with the potential to serve as nanocarrier systems for methotrexate (MTX) used in the chemotherapy of primary central nervous system lymphoma (PCNSL). Nanoparticles were prepared by a double emulsion solvent evaporation technique employing a 3-Factor Box-Behnken experimental design strategy. Analysis of particle size, absolute zeta potential, polydispersity (Pdl), morphology, drug-loading capacity (DLC), structural transitions through FTIR spectroscopy, and drug release kinetics was undertaken. Molecular modelling elucidated the mechanisms of the experimental findings. Nanoparticles with particle sizes ranging from 211.0 to 378.3 nm and a recovery range of 36.8–86.2 mg (Pdl ≤ 0.5) were synthesized. DLC values were initially low (12 ± 0.5%) but were finally optimized to 98 ± 0.3%. FTIR studies elucidated the comixing of MTX within the nanoparticles. An initial burst release (50% of MTX released in 24 hours) was obtained which was followed by a prolonged release phase of MTX over 84 hours. SEM images revealed near-spherical nanoparticles, while TEM micrographs revealed the presence of MTX within the nanoparticles. Stable nanoparticles were formed as corroborated by the chemometric modelling studies undertaken. PMID:22919501

  11. Poly methacrylic acid modified CDHA nanocomposites as potential pH responsive drug delivery vehicles.

    PubMed

    Victor, Sunita Prem; Sharma, Chandra P

    2013-08-01

    The objective of this study was to prepare pH sensitive polymethacrylic acid-calcium deficient hydroxyapatite (CDHA) nanocomposites. The CDHA nanoparticles were prepared by coprecipitation method. The modification of CDHA by methacrylic acid (MA) was achieved by AIBN initiated free radical polymerization with sodium bisulphite as catalyst followed by emulsion technique. These nanocomposites with a half life of 8h consisted of high aspect ratio, needle like particles and exhibited an increase in swelling behaviour with pH. The in vivo potential of the nanocomposites was evaluated in vitro by the results of cell aggregation, protein adsorption, MTT assay and haemolytic activity. The invitro loading and release studies using albumin as a model drug indicate that the nanocomposites gave better loading when compared to the CDHA nanoparticles and altered the drug release rates. The nanocomposites also exhibited good uptake on C6 glioma cells as studied by fluorescence microscopy. The results obtained suggest that these nanocomposites have great potential for oral controlled protein delivery and can be extended further for intracellular drug delivery applications.

  12. pH-responsive jello: gelatin gels containing fatty acid vesicles.

    PubMed

    Dowling, Matthew B; Lee, Jae-Ho; Raghavan, Srinivasa R

    2009-08-04

    We describe a new way to impart pH-responsive properties to gels of biopolymers such as gelatin. This approach involves the embedding of pH-sensitive nanosized vesicles within the gel. The vesicles employed here are those of sodium oleate (NaOA), a fatty-acid-based amphiphile with a single C18 tail. In aqueous solution, NaOA undergoes a transition from vesicles at a pH approximately 8 to micelles at a pH higher than approximately 10. Here, we combine NaOA and gelatin at pH 8.3 to create a vesicle-loaded gel and then bring the gel in contact with a pH 10 buffer solution. As the buffer diffuses into the gel, the vesicles within the gel get transformed into micelles. Accordingly, a vesicle-micelle front moves through the gel, and this can be visually identified by the difference in turbidity between the two regions. Vesicle disruption can also be done in a spatially selective manner to create micelle-rich domains within a vesicle-loaded gel. A possible application of the above approach is in the area of pH-dependent controlled release. A vesicle-to-micelle transition releases hydrophilic solutes encapsulated within the vesicles into the bulk gel, and in turn these solutes can rapidly diffuse out of the gel into the external bath. Experiments with calcein dye confirm this concept and show that we can indeed use the pH in the bath to tune the release rate of solutes from vesicle-loaded gels.

  13. Poly-lactic acid and agarose gelatin play an active role in the recovery of spinal cord injury.

    PubMed

    Deng, Qi-Yue; Li, Shu-Rong; Cai, Wen-Qin; Su, Bing-Yin

    2006-03-01

    Objective To investigate the role of poly-lactic acid and agarose gelatin in promoting the functional recovery of the injured spinal cord. Methods Poly-lactic acid (PLA) or agarose was embedded in the space between two stumps of the hemisectioned spinal cord. Immunohistochemistry was used to show astroglia proliferation and the infiltration of RhoA-positive cells. Locomotor activity recovery was evaluated by testing the function of hindlimbs. Results Astroglias and RhoA labeled non-neuronal cells accumulated in the area adjacent to the implant, while the number of RhoA-positive cells was decreased dramatically in the absence of implant. Animals implanted with agarose gelatin recovered more quickly than those with PLA, concomitant with a higher survival rate of the neurons. Conclusion Both PLA and agarose gelatin benefited the recovery of spinal cord after injury by providing a scaffold for astroglia processes. Modulation of the rigidity, pore size and inner structure of PLA and agarose gelatin might make these biodegradable materials more effective in the regeneration of the central nervous system (CNS).

  14. Effect of carbodiimide-derivatized hyaluronic acid gelatin on preventing postsurgical intra-abdominal adhesion formation and promoting healing in a rat model.

    PubMed

    Yuan, Fang; Lin, Long-Xiang; Zhang, Hui-Hui; Huang, Dan; Sun, Yu-Long

    2016-05-01

    Adhesions often occur after abdominal surgery. It could cause chronic pelvic pain, intestinal obstruction, and infertility. A hydrogel biomaterial, carbodiimide-derivatized hyaluronic acid gelatin (cd-HA gelatin), has been successfully used to reduce adhesion formation after flexor tendon grafting. This study investigated the efficacy of cd-HA gelatin in preventing postsurgical peritoneal adhesions in a rat model. The surgical traumas were created on the underlying muscle of the abdominal wall and the serosal layer of the cecum. The wounds were covered with or without cd-HA gelatin. Animals were euthanized at day 14 after surgery. Adhesion formation was assessed with adhesion degree and adhesion breaking strength. The healing of abdominal wall was evaluated with biomechanical testing and histological analysis. The adhesions occurred in all rats (n = 12) without cd-HA gelatin treatment. The application of cd-HA gelatin significantly reduced the adhesion rate from 100% to 58%. The decrease of adhesion breaking strength also manifested that cd-HA gelatin could reduce postsurgical intra-abdominal adhesion formation. Moreover, it was found that cd-HA gelatin was a safe material and could promote tissue healing. The cd-HA gelatin hydrogel could reduce the formation of intra-abdominal adhesions without adversely effects on wound healing. © 2016 Wiley Periodicals, Inc.

  15. Synthesis and properties of poly(methyl methacrylate-2-acrylamido-2-methylpropane sulfonic acid)/PbS hybrid composite

    SciTech Connect

    Preda, N.; Rusen, E.; Musuc, A.; Enculescu, M.; Matei, E.; Marculescu, B.; Fruth, V.; Enculescu, I.

    2010-08-15

    The synthesis of a new hybrid composite based on PbS nanoparticles and poly(methyl methacrylate-2-acrylamido-2-methylpropane sulfonic acid) [P(MMA-AMPSA)] copolymer is reported. The chemical synthesis consists in two steps: (i) a surfactant-free emulsion copolymerization between methyl methacrylate and 2-acrylamido-2-methylpropane sulfonic acid and (ii) the generation of PbS particles in the presence of the P(MMA-AMPSA) latex, from the reaction between lead nitrate and thiourea. The composite was studied by scanning electron microscopy (SEM), X-ray diffraction, FTIR spectroscopy, thermogravimetric analysis and differential scanning calorimetry. The microstructure observed using SEM proves that the PbS nanoparticles are well dispersed in the copolymer matrix. The X-ray diffraction measurements demonstrate that the PbS nanoparticles have a cubic rock salt structure. It was also found that the inorganic semiconductor nanoparticles improve the thermal stability of the copolymer matrix.

  16. Smart poly(2-hydroxyethyl methacrylate/itaconic acid) hydrogels for biomedical application

    NASA Astrophysics Data System (ADS)

    Tomić, Simonida Lj; Mićić, Maja M.; Dobić, Sava N.; Filipović, Jovanka M.; Suljovrujić, Edin H.

    2010-05-01

    pH- and temperature-sensitive hydrogels, based on 2-hydroxyethyl methacrylate (HEMA) and itaconic acid (IA) copolymers, were prepared by γ-irradiation and characterized in order to examine their potential use in biomedical applications. The influence of comonomer ratio in these smart copolymers on their morphology, mechanical and thermal properties, biocompatibility and microbe penetration capability was investigated. The mechanical properties of copolymers were investigated using the dynamic mechanical analysis (DMA), while their thermal properties and morphology were examined by thermogravimetric analysis (TGA) and scanning electron microscopy (SEM). The morphology, mechanical and thermal properties of these hydrogels were found to be suitable for most requirements of biomedical applications. The in vitro study of P(HEMA/IA) biocompatibility showed no evidence of cell toxicity nor any considerable hemolytic activity. Furthermore, the microbe penetration test showed that neither Staphylococcus aureus nor Escherichia coli passed through the hydogel dressing; thus the P(HEMA/IA) dressing could be considered a good barrier against microbes. All results indicate that stimuli-responsive P(HEMA/IA) hydrogels have great potential for biomedical applications, especially for skin treatment and wound dressings.

  17. Efficient structural characterization of poly(methacrylic acid) by activated-electron photodetachment dissociation.

    PubMed

    Girod, Marion; Brunet, Claire; Antoine, Rodolphe; Lemoine, Jérôme; Dugourd, Philippe; Charles, Laurence

    2012-01-01

    Characterization of end-groups in poly(methacrylic acid) (PMAA) was achieved using tandem mass spectrometry after activated-electron photodetachment dissociation (activated-EPD). In this technique, multiply deprotonated PMAA oligomers produced in the negative-ion mode of electrospray ionization were oxidized into radical anions upon electron photodetachment using a 220 nm laser wavelength, and further activated by collision. In contrast to conventional collision induced dissociation of negatively charged PMAA, which mainly consists of multiple dehydration steps, fragmentation of odd-electron species is shown to proceed via a radical-induced decarboxylation, followed by reactions involving backbone bond cleavages, giving rise to product ions containing one or the other oligomer termination. A single radical-induced mechanism accounts for the four main fragment series observed in MS/MS. The relative position of the radical and of the anionic center in distonic precursor ions determines the nature of the reaction products. Experiments performed using PMAA sodium salts allowed us to account for relative abundances of product ions in series obtained from PMAA, revealing that ion stability is ensured by hydrogen bonds within pairs of MAA units.

  18. Effect of cationic surfactants on the conformational transition of poly(methacrylic acid)

    SciTech Connect

    Chu, D.; Thomas, J.K.

    1986-10-01

    The interaction between poly(methacrylic acid) and alkyltrimethylammonium bromide, C/sub n/TAB, cationic surfactants has been investigated in aqueous solutions of pH 8, by use of the photophysics of pyrene and its derivatives. Photophysical studies of these fluorescent probes, both steady-state and pulsed laser studies, show that a conformational transition of PMA is induced by C/sub n/TAB. The surfactant induces a coiling up of PMA chains at pH 8, which takes place via a cooperative process. This effect takes place when the concentration of C/sub n/TAB is above a critical aggregate concentration, CAC. The CAC is 1 or 2 orders of magnitude less than the cmc of the corresponding micelle. There is significant effect of surfactant chain length and PMA concentration on the CAC, which provides information on the nature of the CAC and the mechanism of the PMA transition. A model is suggested for the aggregation of PMA-C/sub 10/TAB based on experimental data. Studies show that the aggregate consists of about 100 C/sub 10/TAB molecules and 1 coiled polymer chain.

  19. Synthesis of comb-like copolymers from renewable resources: Itaconic anhydride, stearyl methacrylate and lactic acid

    NASA Astrophysics Data System (ADS)

    Shang, Shurui

    The synthesis and properties of comb-like copolymers and ionomers derived from renewable resources: itaconic anhydride (ITA), stearyl methacrylate (SM) and lactic acid (LA) are described. The copolymers based on ITA and SM (ITA-SM) were nearly random with a slight alternating tendency. The copolymers exhibited a nanophase-separated morphology, with the stearate side-chains forming a bilayer, semi-crystalline structure. The crystalline side-chains suppressed molecular motion of the main-chain, so that a glass transition temperature (Tg) was not resolved unless the ITA concentration was sufficiently high so that Tg > the melting point (Tm). The softening point and modulus of the copolymers increased with the increasing ITA concentration, but the thermal stability decreased. The ITA moiety along the main chain of the copolymers was neutralized with metal acetates to produce Na-, Ca- and Zn- random ionomers with comb-like architectures. In general, the incorporation of the ionic groups increased the Tg and suppressed the crystallinity of the side-chain packing. Ionomers with high SM side-chain density had two competing driving forces for self-assembled nano-phase separation: ionic aggregation and side-chain crystalline packing. Upon neutralization, a morphological transition from semi-crystalline lamella to spherical ionic aggregation was observed by small angle X-ray scattering (SAXS) analysis and transmission electron microscopy (TEM). Thermomechanical analysis revealed an increasing resistance to penetration deformation with an increasing degree of neutralization and an apparent rubbery plateau was observed above Tg. A controlled transesterification of PLA in glassware was an effective way to prepare a methacrylate functionalized PLA macromonomer with controlled molecular weight, which was used to synthesize a variety of copolymers. The copolymerization of this functionalized PLA macromonomer with ITA totally suppressed the side-chain crystallinity for the PLA chain

  20. Theoretical and experimental research on the self-assembled system of molecularly imprinted polymers formed by salbutamol and methacrylic acid.

    PubMed

    Jun-Bo, Liu; Yang, Shi; Shan-Shan, Tang; Rui-Fa, Jin

    2015-03-01

    The quantum chemical method was applied for screening functional monomers in the rational design of salbutamol-imprinted polymers. Salbutamol was the template molecule, and methacrylic acid was the single functional monomer. The LC-WPBE/6-31G(d,p) method was used to investigate the geometry optimization, active sites, natural bond orbital charges, binding energies of the imprinted molecule, and solvation energy. The mechanism of action between salbutamol and methacrylic acid was also discussed. The theoretical results show that salbutamol interacts with functional monomers by hydrogen bonds, and the salbutamol-imprinted polymers with a ratio of 1:4 (salbutamol/methacrylic acid) in acetonitrile had the highest stability. The salbutamol-imprinted polymers were prepared by precipitation polymerization. The experimental results indicated that the maximum adsorption capacity for salbutamol toward molecularly imprinted polymers was 7.33 mg/g, and the molecularly imprinted polymers had a higher selectivity for salbutamol than for norepinephrine and terbutaline sulfate. Herein, the studies can provide theoretical and experimental references for the salbutamol molecular imprinted system.

  1. Optimized mobile phase for CEC of acetylsalicylic acid and its impurities using a methacrylate-based monolithic column.

    PubMed

    Tanret, Indiana; Mangelings, Debby; Vander Heyden, Yvan

    2011-08-01

    In the past few years, monolithic methacrylate-based columns have attracted some attention in separation science. The mobile-phase optimization on these columns for drug analysis has not yet been thoroughly examined. This paper evaluates the separation of acetylsalicylic acid and its impurities as a case study. First, the best pH was determined as 2.3. Methacrylate-based phases can be employed at such pH because they remain charged, necessary to generate electro-osmotic flow. Then, a suitable solvent strength was determined. Trifluoroacetic acid (0.1%) was added to the mobile phase to improve peak shapes. The optimal organic modifier composition was then determined, using isoeluotropic mobile phases, based on the theory of Snyder's solvent triangle. Quadratic models were built to predict the retention of the compounds at all mobile-phase compositions within the triangle. The predictions were tested and found appropriate. Eventually, a baseline separation of acetylsalicylic acid and its impurities was not obtained. However, it could be concluded that one can optimize the mobile phase on methacrylate-based monolithic columns in CEC using Snyder's solvent triangle approach. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Phenylboronic acid-decorated gelatin nanoparticles for enhanced tumor targeting and penetration

    NASA Astrophysics Data System (ADS)

    Wang, Xin; Wei, Bing; Cheng, Xu; Wang, Jun; Tang, Rupei

    2016-09-01

    Phenylboronic acid-decorated nanoparticles (NPs) were prepared for tumor-targeted drug delivery. 3-carboxyphenylboronic acid (3-CPBA) was modified on the surface of conventional gelatin NPs (designated as NP1) to give tumor-targeting NPs (designated as NP2). The morphology and stability of NP1 and NP2 were then investigated using transmission electron microscopy, scanning electron microscopy, and dynamic light scattering. The results show that both NP1 and NP2 are spherical-like and kinetically stable under various conditions. Doxorubicin hydrochloride (DOX) was used as a model anticancer drug and was loaded into NP1 (NP1-DOX) and NP2 (NP2-DOX). The i n vitro cellular uptake and cytotoxicity of NP1-DOX and NP2-DOX were measured using SH-SY5Y cells, H22 cells, and HepG2 cells. Tumor penetration, accumulation, and antitumor activity were investigated using SH-SY5Y tumor-like spheroids and H22 tumor-bearing mice. All results demonstrated that the conjugation of 3-CPBA can efficiently enhance non-targeted NPs’ tumor-homing activity, thus improving their tumor accumulation and antitumor effect.

  3. Structural Analysis Of Ethylene/Acrylic And Methacrylic Acid Copolymers Using Fourier Self-Deconvolution Of Infrared Spectra

    NASA Astrophysics Data System (ADS)

    Harthcock, Matthew A.

    1985-12-01

    Fourier self-deconvolution (FSD) has been applied to several regions of the infrared spectra of ethylene/acrylic and methacrylic acid copolymers to obtain detailed information on the structure of these copolymers. The computer assisted technique has been applied to the 1050-830 cm-1 region of the infrared spectrum of the copolymers to resolve the vinyl (909 cm-1) and vinylidene (887 cm-1) CH2 wagging vibrations from the in-phase out-of-plane hydrogen deformation vibration of the acid dimer (943 cm-1). The technique was applied to the carbonyl stretching vibration region (1820-1660 cm-1) to study the structure of the acid groups. Two distinct hydrogen bonded (1710 and 1696 cm-1) and free (1758 and 1745 cm-1) acid group structures were observed for the 9% acrylic acid copolymers, while the methacrylic acid copolymer showed predominantly one hydrogen bonded (1696 cm-1) and one free (1758 cm-1) acid group structure. Also, the 6.5% acrylic acid copolymers showed essentially one type of hydrogen bonded (1706 cm-1) carbonyl and two free carbonyl stretching absorptions (1758 and 1745 cm-1).

  4. Effects of ultraviolet irradiation on bonding strength between Co-Cr alloy and citric acid-crosslinked gelatin matrix.

    PubMed

    Inoue, Motoki; Sasaki, Makoto; Katada, Yasuyuki; Taguchi, Tetsushi

    2014-02-01

    Novel techniques for creating a strong bond between polymeric matrices and biometals are required. We immobilized polymeric matrices on the surface of biometal for drug-eluting stents through covalent bond. We performed to improve the bonding strength between a cobalt-chromium alloy and a citric acid-crosslinked gelatin matrix by ultraviolet irradiation on the surface of cobalt-chromium alloy. The ultraviolet irradiation effectively generated hydroxyl groups on the surface of the alloy. The bonding strength between the gelatin matrix and the alloy before ultraviolet irradiation was 0.38 ± 0.02 MPa, whereas it increased to 0.48 ± 0.02 MPa after ultraviolet irradiation. Surface analysis showed that the citric acid derivatives occurred on the surface of the cobalt-chromium alloy through ester bond. Therefore, ester bond formation between the citric acid derivatives active esters and the hydroxyl groups on the cobalt-chromium alloy contributed to the enhanced bonding strength. Ultraviolet irradiation and subsequent immobilization of a gelatin matrix using citric acid derivatives is thus an effective way to functionalize biometal surfaces.

  5. Acrylic acid-methyl methacrylate copolymer for oral prolonged drug release.

    PubMed

    Vijay, Saurabh; Sati, O P; Majumdar, Dipak K

    2010-09-01

    Acrylic acid (AA)-methyl methacrylate (MMA) based copolymers, in different molar ratios (3:7, 4:6, 5:5, 6:4, and 7:3) were synthesized using tetrahydrofuran as solvent and AIBN as free radical initiator. Increase in acrylic acid concentration promoted pH-dependent swelling of copolymer and copolymer AA:MMA (3:7) was selected due to minimum swelling. ATR/FTIR and (1)H NMR spectra of the copolymer showed absence of vinyl bond/protons present in the monomers suggesting successful polymerization. The copolymer was hemocompatible. Flurbiprofen sodium microspheres made with the copolymer, by oil/oil solvent evaporation, were spherical, anionic (zeta potential -59.0 mV) and contained 4.53% drug. ATR spectrum of microspheres showed peaks for aromatic C=C stretching and substituted benzene ring, indicating entrapment of flurbiprofen. XRD analysis revealed crystalline structure of flurbiprofen while copolymer and microspheres were amorphous. DSC thermograms showed a sharp melting endotherm of flurbiprofen sodium at 129.26 degrees C against broad endotherms of copolymer and microspheres having peaks at 82.24 and 86.59 degrees C, respectively. The thermogram of microspheres did not show the melting peak of flurbiprofen. The microspheres exhibited no drug release at pH <6.8 and released 83.4 and 99% drug at pH 6.8 and 7.4 in 3 h. The microspheres did not adhere on gastric mucosa at pH 1.2 but showed mucoadhesion time of 28 min on intestinal mucosa at pH 6.8. Thus, the microspheres on oral administration, would release the drug in distal ileum, suggesting the potential of the hemocompatible copolymer for enteric coating for prolonged drug release.

  6. Bio-sorption of acidic gelatine hydro-gels implanted in the back tissues of Fisher's rats.

    PubMed

    Taira, M; Furuuchi, H; Saitoh, S; Sugiyama, Y; Sekiyama, S; Araki, Y; Tabata, Y

    2005-05-01

    Recent advance in tissue engineering therapy requires new scaffold materials. Acidic gelatine powders (10 wt%) were, thus, dissolved in water, were or were not cross-linked, and freeze-dried. After sterilization, prepared small sponges were implanted in 7-week-old Fisher's rats' subcutaneous tissues for up to 2 weeks. Sponges absorbed body fluid and changed into hydro-gels in vivo. Non-cross-linked hydro-gels were absorbed within 3 days, while cross-linked hydro-gels were eliminated after 7 days' implantation. Histological observations revealed that the common captivation process was mild while granulocytes and macrophages were encountered. Because acidic gelatine sponges can accommodate various basic growth factors, it can be speculated that prepared sponges might be used as short-time hydro-gel scaffolds and growth-factor carriers.

  7. Graft polymerization of acrylic acid and methacrylic acid onto poly(vinylidene fluoride) powder in presence of metallic salt and sulfuric acid

    NASA Astrophysics Data System (ADS)

    Deng, Bo; Yu, Yang; Zhang, Bowu; Yang, Xuanxuan; Li, Linfan; Yu, Ming; Li, Jingye

    2011-02-01

    Poly(vinylidene fluoride) (PVDF) powder was grafted with acrylic acid (AAc) or methacrylic acid (MAA) by the pre-irradiation induced graft polymerization technique. The presence of graft chains was proven by FT-IR spectroscopy. The degree of grafting (DG) was calculated by the acid-base back titration method. The synergistic effect of acid and Mohr's salt on the grafting kinetics was examined. The results indicated that adding sulfuric acid and Mohr's salt simultaneously in AAc or MAA solutions led to a strong enhancement in the degree of grafting. The grafted PVDF powder was cast into microfiltration (MF) membranes using the phase inversion method and some properties of the obtained MF membranes were characterized.

  8. Triblock copolyampholytes from 5-(N,N-dimethyl amino)isoprene styrene, and methacrylic acid: Synthesis and solution properties

    NASA Astrophysics Data System (ADS)

    Bieringer, R.; Abetz, V.; Müller, A. H. E.

    ABC triblock copolymers of the type poly[5-(N,N-dimethyl amino)isoprene]-block-polystyrene-block-poly(tert-butyl methacrylate) (AiST) were synthesized and hydrolyzed to yield poly[5-(N,N-dimethyl amino)isoprene]-block-polystyrene-block-poly(methacrylic acid) (AiSA) triblock copolyampholytes. Due to a complex solubility behavior the solution properties of these materials had to be investigated in THF/water solvent mixtures. Potentiometric titrations of AiSA triblock copolyampholytes showed two inflection points with the A block being deprotonated prior to the Ai hydrochloride block thus forming a polyzwitterion at the isoelectric point (iep). The aggregation behavior was studied by dynamic light scattering (DLS) and freeze-fracture/transmission electron microscopy (TEM). Large vesicular structures with almost pH-independent radii were observed.

  9. Viscoelasticity of hyaluronic acid-gelatin hydrogels for vocal fold tissue engineering.

    PubMed

    Kazemirad, Siavash; Heris, Hossein K; Mongeau, Luc

    2016-02-01

    Crosslinked injectable hyaluronic acid (HA)-gelatin (Ge) hydrogels have remarkable viscoelastic and biological properties for vocal fold tissue engineering. Patient-specific tuning of the viscoelastic properties of this injectable biomaterial could improve tissue regeneration. The frequency-dependent viscoelasticity of crosslinked HA-Ge hydrogels was measured as a function of the concentration of HA, Ge, and crosslinker. Synthetic extracellular matrix hydrogels were fabricated using thiol-modified HA and Ge, and crosslinked by poly(ethylene glycol) diacrylate. A recently developed characterization method based on Rayleigh wave propagation was used to quantify the frequency-dependent viscoelastic properties of these hydrogels, including shear storage and loss moduli, over a broad frequency range; that is, from 40 to 4000 Hz. The viscoelastic properties of the hydrogels increased with frequency. The storage and loss moduli values and the rate of increase with frequency varied with the concentrations of the constituents. The range of the viscoelastic properties of the hydrogels was within that of human vocal fold tissue obtained from in vivo and ex vivo measurements. Frequency-dependent parametric relations were obtained using a linear least-squares regression. The results are useful to better fine-tune the storage and loss moduli of HA-Ge hydrogels by varying the concentrations of the constituents for use in patient-specific treatments. © 2015 Wiley Periodicals, Inc.

  10. Thermosensitive hydrogel made of ferulic acid-gelatin and chitosan glycerophosphate.

    PubMed

    Cheng, Yung-Hsin; Yang, Shu-Hua; Liu, Chia-Ching; Gefen, Amit; Lin, Feng-Huei

    2013-02-15

    Reactive oxygen species-induced oxidative stress is involved in apoptosis of nucleus pulposus (NP) cells that can alter cellular phenotype and accelerate disc degeneration. Ferulic acid (FA) possesses an excellent antioxidant and anti-inflammatory properties. In the study, we developed the thermosensitive FA-gelatin/chitosan/glycerol phosphate (FA-G/C/GP) hydrogel which was applied as a sustained release system of FA to treat NP cells from the damage caused by oxidative stress. The gelation temperature of the FA-G/C/GP hydrogel was 32.17 °C. NP cells submitted to oxidative stress promoted by H(2)O(2), and post-treated with FA-G/C/GP exhibited down-regulation of MMP-3 and up-regulation aggrecan and type II collagen in mRNA level. The sulfated-glycosaminoglycan production was increased and the apoptosis was inhibited in the post-treatment group. The results suggest that the thermosensitive FA-G/C/GP hydrogel can treat NP cells from the damage caused by oxidative stress and may apply in minimally invasive surgery for NP regeneration.

  11. Temporal MRI characterization of gelatin/hyaluronic acid/chondroitin sulfate sponge for cartilage tissue engineering.

    PubMed

    Chou, Cheng-Hung; Lee, Herng-Sheng; Siow, Tiing Yee; Lin, Ming-Huang; Kumar, Amit; Chang, Yue-Cune; Chang, Chen; Huang, Guo-Shu

    2013-08-01

    A tri-copolymer sponge consisting of gelatin, hyaluronic acid, and chondroitin sulfate (GHC) was designed to mimic the cartilage environment in vivo for cartilage regeneration. The present study aimed to temporally characterize the magnetic resonance relaxation time of GHC constructs in vivo in a rodent heterotopic model. GHC sponges with cells (GHCc) or without cells (GHC) implanted in rat leg muscle were monitored using MRI (4.7 T MR scanner) on day 0, 7, 14, and 21 after implantation. The results revealed that the transverse relaxation time (T2) of GHC constructs decreased significantly over time when compared to the T2 of GHCc constructs. However, the longitudinal relaxation time (T1) of GHCc and GHC constructs remained stable. Moreover, hematoxylin and eosin and immunohistochemical staining with antibodies to S100 protein, and types I and II collagen showed that normal morphology, phenotype, and function of chondrocytes were preserved in the GHCc construct. Thus, we concluded that GHC constructs adequately support chondrocyte growth and function. On top of that, T2 may be a useful tool for monitoring cartilage regeneration in GHC constructs.

  12. Sorption of zinc by novel pH-sensitive hydrogels based on chitosan, itaconic acid and methacrylic acid.

    PubMed

    Milosavljević, Nedeljko B; Ristić, Mirjana Đ; Perić-Grujić, Aleksandra A; Filipović, Jovanka M; Strbac, Svetlana B; Rakočević, Zlatko Lj; Kalagasidis Krušić, Melina T

    2011-08-30

    Novel pH-sensitive hydrogels based on chitosan, itaconic acid and methacrylic acid were applied as adsorbents for the removal of Zn(2+) ions from aqueous solution. In batch tests, the influence of solution pH, contact time, initial metal ion concentration and temperature was examined. The sorption was found pH dependent, pH 5.5 being the optimum value. The adsorption process was well described by the pseudo-second order kinetic. The hydrogels were characterized by spectral (Fourier transform infrared-FTIR) and structural (SEM/EDX and atomic force microscopy-AFM) analyses. The surface topography changes were observed by atomic force microscopy, while the changes in surface composition were detected using phase imaging AFM. The negative values of free energy and enthalpy indicated that the adsorption is spontaneous and exothermic one. The best fitting isotherms were Langmuir and Redlich-Peterson and it was found that both linear and nonlinear methods were appropriate for obtaining the isotherm parameters. However, the increase of temperature leads to higher adsorption capacity, since swelling degree increased with temperature.

  13. Controlling Internal Organization of Multilayer Poly(methacrylic acid) Hydrogels with Polymer Molecular Weight

    DOE PAGES

    Kozlovskaya, Veronika; Zavgorodnya, Oleksandra; Ankner, John F.; ...

    2015-11-16

    Here, we report on tailoring the internal architecture of multilayer-derived poly(methacrylic acid) (PMAA) hydrogels by controlling the molecular weight of poly(N-vinylpyrrolidone) (PVPON) in hydrogen-bonded (PMAA/PVPON) layer-by-layer precursor films. The hydrogels are produced by cross-linking PMAA in the spin-assisted multilayers followed by PVPON release. We found that the thickness, morphology, and architecture of hydrogen-bonded films and the corresponding hydrogels are significantly affected by PVPON chain length. For all systems, an increase in PVPON molecular weight from Mw = 2.5 to 1300 kDa resulted in increased total film thickness. We also show that increasing polymer Mw smooths the hydrogen-bonded film surfaces butmore » roughens those of the hydrogels. Using deuterated dPMAA marker layers in neutron reflectometry measurements, we found that hydrogen-bonded films reveal a high degree of stratification which is preserved in the cross-linked films. We observed dPMAA to be distributed more widely in the hydrogen-bonded films prepared with small Mw PVPON due to the greater mobility of short-chain PVPON. Furthermore, these variations in the distribution of PMAA are erased after cross-linking, resulting in a distribution of dPMAA over about two bilayers for all Mw but being somewhat more widely distributed in the films templated with higher Mw PVPON. Finally, our results yield new insights into controlling the organization of nanostructured polymer networks using polymer molecular weight and open opportunities for fabrication of thin films with well-organized architecture and controllable function.« less

  14. Controlling Internal Organization of Multilayer Poly(methacrylic acid) Hydrogels with Polymer Molecular Weight

    SciTech Connect

    Kozlovskaya, Veronika; Zavgorodnya, Oleksandra; Ankner, John F.; Kharlampieva, Eugenia

    2015-11-16

    Here, we report on tailoring the internal architecture of multilayer-derived poly(methacrylic acid) (PMAA) hydrogels by controlling the molecular weight of poly(N-vinylpyrrolidone) (PVPON) in hydrogen-bonded (PMAA/PVPON) layer-by-layer precursor films. The hydrogels are produced by cross-linking PMAA in the spin-assisted multilayers followed by PVPON release. We found that the thickness, morphology, and architecture of hydrogen-bonded films and the corresponding hydrogels are significantly affected by PVPON chain length. For all systems, an increase in PVPON molecular weight from Mw = 2.5 to 1300 kDa resulted in increased total film thickness. We also show that increasing polymer Mw smooths the hydrogen-bonded film surfaces but roughens those of the hydrogels. Using deuterated dPMAA marker layers in neutron reflectometry measurements, we found that hydrogen-bonded films reveal a high degree of stratification which is preserved in the cross-linked films. We observed dPMAA to be distributed more widely in the hydrogen-bonded films prepared with small Mw PVPON due to the greater mobility of short-chain PVPON. Furthermore, these variations in the distribution of PMAA are erased after cross-linking, resulting in a distribution of dPMAA over about two bilayers for all Mw but being somewhat more widely distributed in the films templated with higher Mw PVPON. Finally, our results yield new insights into controlling the organization of nanostructured polymer networks using polymer molecular weight and open opportunities for fabrication of thin films with well-organized architecture and controllable function.

  15. Acute effects of breakfasts containing alpha-lactalbumin, or gelatin with or without added tryptophan, on hunger, 'satiety' hormones and amino acid profiles.

    PubMed

    Nieuwenhuizen, Arie G; Hochstenbach-Waelen, Ananda; Veldhorst, Margriet A B; Westerterp, Klaas R; Engelen, Mariëlle P K J; Brummer, Robert-Jan M; Deutz, Nicolaas E P; Westerterp-Plantenga, Margriet S

    2009-06-01

    Proteins are the most satiating macronutrients. Tryptophan (TRP) may contribute to the satiating effect, as it serves as a precursor for the anorexigenic neurotransmitter serotonin. To address the role of TRP in the satiating properties of dietary protein, we compared three different breakfasts, containing either alpha-lactalbumin (high in TRP), gelatin (low in TRP) or gelatin with added TRP (gelatin+TRP, high in TRP), on appetite. Twenty-four subjects (22-29 kg/m2; aged 19-37 years) received a subject-specific breakfast at t = 0 with 10, 55 and 35 % energy from protein, carbohydrate and fat respectively in a randomised, single-blind design. Hunger, glucagon-like peptide (GLP)-1, ghrelin, amino acid concentrations and energy intake during a subsequent lunch were determined. Suppression of hunger was stronger 240 min after the breakfast with alpha-lactalbumin compared with gelatin and gelatin+TRP. Total plasma amino acid concentrations were lower with alpha-lactalbumin compared with gelatin with or without TRP (from t = 180-240 min). TRP concentrations were higher after alpha-lactalbumin than after gelatin with or without TRP from t = 0-100 min, whereas from t = 100-240 min, TRP concentrations were lower after gelatin than after alpha-lactalbumin and gelatin+TRP. The plasma ratio of TRP to other large neutral amino acids (LNAA) was, only at t = 100 min, lower after gelatin+TRP than after the other breakfasts. Plasma amino acid responses, TRP concentrations and TRP:LNAA ratios were not correlated with hunger. GLP-1 and ghrelin concentrations were similar for all diets. Energy intake during a subsequent lunch was similar for all diets. Summarised, an alpha-lactalbumin breakfast suppresses hunger more than a gelatin or gelatin+TRP breakfast. This cannot be explained by (possible) differences found in TRP concentrations and TRP:LNAA ratios in the breakfasts and in plasma, as well as in circulating total amino acids, GLP-1 and ghrelin.

  16. Effect of methacrylic acid beads on the sonic hedgehog signaling pathway and macrophage polarization in a subcutaneous injection mouse model.

    PubMed

    Lisovsky, Alexandra; Zhang, David K Y; Sefton, Michael V

    2016-08-01

    Poly(methacrylic acid-co-methyl methacrylate) (MAA) beads promote a vascular regenerative response when used in diabetic wound healing. Previous studies reported that MAA beads modulated the expression of sonic hedgehog (Shh) and inflammation related genes in diabetic wounds. The aim of this work was to follow up on these observations in a subcutaneous injection model to study the host response in the absence of the confounding factors of diabetic wound healing. In this model, MAA beads improved vascularization in healthy mice of both sexes compared to control poly(methyl methacrylate) (MM) beads, with a stronger effect seen in males than females. MAA-induced vessels were perfusable, as evidenced from the CLARITY-processed images. In Shh-Cre-eGFP/Ptch1-LacZ non-diabetic transgenic mice, the increased vessel formation was accompanied by a higher density of cells expressing GFP (Shh) and β-Gal (patched 1, Ptch1) suggesting MAA enhanced the activation of the Shh pathway. Ptch1 is the Shh receptor and a target of the pathway. MAA beads also modulated the inflammatory cell infiltrate in CD1 mice: more neutrophils and more macrophages were noted with MAA relative to MM beads at days 1 and 7, respectively. In addition, MAA beads biased macrophages towards a MHCII-CD206+ ("M2") polarization state. This study suggests that the Shh pathway and an altered inflammatory response are two elements of the complex mechanism whereby MAA-based biomaterials effect vascular regeneration.

  17. Alterations in juvenile diploid and triploid African catfish skin gelatin yield and amino acid composition: Effects of chlorpyrifos and butachlor exposures.

    PubMed

    Karami, Ali; Karbalaei, Samaneh; Zad Bagher, Fariba; Ismail, Amin; Simpson, Stuart L; Courtenay, Simon C

    2016-08-01

    Skin is a major by-product of the fisheries and aquaculture industries and is a valuable source of gelatin. This study examined the effect of triploidization on gelatin yield and proximate composition of the skin of African catfish (Clarias gariepinus). We further investigated the effects of two commonly used pesticides, chlorpyrifos (CPF) and butachlor (BUC), on the skin gelatin yield and amino acid composition in juvenile full-sibling diploid and triploid African catfish. In two separate experiments, diploid and triploid C. gariepinus were exposed for 21 days to graded CPF [mean measured: 10, 16, or 31 μg/L] or BUC concentrations [Mean measured: 22, 44, or 60 μg/L]. No differences in skin gelatin yield, amino acid or proximate compositions were observed between diploid and triploid control groups. None of the pesticide treatments affected the measured parameters in diploid fish. In triploids, however, gelatin yield was affected by CPF treatments while amino acid composition remained unchanged. Butachlor treatments did not alter any of the measured variables in triploid fish. To our knowledge, this study is the first to investigate changes in the skin gelatin yield and amino acid composition in any animal as a response to polyploidization and/or contaminant exposure. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. Controlled release of tyrosol and ferulic acid encapsulated in chitosan-gelatin films after electron beam irradiation

    NASA Astrophysics Data System (ADS)

    Benbettaïeb, Nasreddine; Assifaoui, Ali; Karbowiak, Thomas; Debeaufort, Frédéric; Chambin, Odile

    2016-01-01

    This work deals with the study of the release kinetics of antioxidants (ferulic acid and tyrosol) incorporated into chitosan-gelatin edible films after irradiation processes. The aim was to determine the influence of electron beam irradiation (at 60 kGy) on the retention of antioxidants in the film, their release in water (pH=7) at 25 °C, in relation with the barrier and mechanical properties of biopolymer films. The film preparation process coupled to the irradiation induced a loss of about 20% of tyrosol but did not affect the ferulic acid content. However, 27% of the ferulic acid remained entrapped in the biopolymer network during the release experiments whereas all tyrosol was released. Irradiation induced a reduction of the release rate for both compounds, revealing that cross-linking occurred during irradiation. This was confirmed by the mechanical properties enhancement which tensile strength value significantly increased and by the reduction of permeabilities. Although molecular weights, molar volume and molecular radius of the two compounds are very similar, the effective diffusivity of tyrosol was 40 times greater than that of ferulic acid. The much lower effective diffusion coefficient of ferulic acid as determined from the release kinetics was explained by the interactions settled between ferulic acid molecules and the gelatin-chitosan matrix. As expected, the electron beam irradiation allowed modulating the retention and then the release of antioxidants encapsulated.

  19. Poly-(L-lactic acid) and citric acid-crosslinked gelatin composite matrices as a drug-eluting stent coating material with endothelialization, antithrombogenic, and drug release properties.

    PubMed

    Inoue, Motoki; Sasaki, Makoto; Katada, Yasuyuki; Fujiu, Katsuhito; Manabe, Ichiro; Nagai, Ryozo; Taguchi, Tetsushi

    2013-07-01

    Biodegradable composite matrices comprising poly-(L-lactic acid) (PLLA) and citric acid-crosslinked alkali-treated gelatin (AlGelatin) with endothelialization, antithrombogenic, and drug release properties were prepared. The characterization of composite matrices with various mixing ratios was performed by evaluating their swelling ratio, endothelial cell culture, antithrombogenic tests, and drug release behavior. Tamibarotene (Am80), which specifically inhibits smooth muscle cell proliferation, was employed as the drug. The swelling ratio of composite matrices decreased as the PLLA content decreased. The number of endothelial cells cultured on the surfaces of composite matrices was maximal at the PLLA/AlGelatin-TSC ratio of 80/20. Antithrombogenic tests revealed that the levels of platelets and fibrin network formation decreased as the AlGelatin-TSC content increased. The Am80 release test indicated that the release rate decreased as PLLA content increased. Using the resulting composite matrix, Am80-eluting stents possessing a smooth surface and a coating thickness of ∼15 μm were successfully obtained. Am80 was continuously released from the resulting stent at ∼40%, up to 28 days without burst release. Therefore, Am80-eluting stent with its antithrombogenic and endothelialization properties has great potential for clinical use. Copyright © 2012 Wiley Periodicals, Inc.

  20. Fabrication and mechanical characterization of graphene oxide-reinforced poly (acrylic acid)/gelatin composite hydrogels

    NASA Astrophysics Data System (ADS)

    Faghihi, Shahab; Gheysour, Mahsa; Karimi, Alireza; Salarian, Reza

    2014-02-01

    Hydrogels have found many practical uses in drug release, wound dressing, and tissue engineering. However, their applications are restricted due to their weak mechanical properties. The role of graphene oxide nanosheets (GONS) as reinforcement agent in poly (acrylic acid) (PAA)/Gelatin (Gel) composite hydrogels is investigated. Composite hydrogels are synthesized by thermal initiated redox polymerization method. Samples are then prepared with 20 and 40 wt. % of PAA, an increasing amount of GONS (0.1, 0.2, and 0.3 wt. %), and a constant amount of Gel. Subsequently, cylindrical hydrogel samples are subjected to a series of compression tests in order to measure their elastic modulus, maximum stress and strain. The results exhibit that the addition of GONS increases the Young's modulus and maximum stress of hydrogels significantly as compared with control (0.0 wt. % GONS). The highest Young's modulus is observed for hydrogel with GO (0.2 wt. %)/PAA (20 wt. %), whereas the highest maximum stress is detected for GO (0.2 wt. %)/PAA (40 wt. %) specimen. The addition of higher amounts of GONS leads to a decrease in the maximum stress of the hydrogel GO (0.3 wt. %)/PAA (40 wt. %). No significant differences are detected for the maximum strain among the hydrogel samples, as the amount of GONS increased. These results suggest that the application of GONS could be used to improve mechanical properties of hydrogel materials. This study may provide an alternative for the fabrication of low-cost graphene/polymer composites with enhanced mechanical properties beneficial for tissue engineering applications.

  1. Fish gelatin.

    PubMed

    Boran, Gokhan; Regenstein, Joe M

    2010-01-01

    Gelatin is a multifunctional ingredient used in foods, pharmaceuticals, cosmetics, and photographic films as a gelling agent, stabilizer, thickener, emulsifier, and film former. As a thermoreversible hydrocolloid with a narrower gap between its melting and gelling temperatures, both of which are below human body temperature, gelatin provides unique advantages over carbohydrate-based gelling agents. Gelatin is mostly produced from pig skin, and cattle hides and bones. Some alternative raw materials have recently gained attention from both researchers and the industry not just because they overcome religious concerns shared by Jews and Muslims but also because they provide, in some cases, technological advantages over mammalian gelatins. Fish skins from a number of fish species are among the other sources that have been comprehensively studied as sources for gelatin production. Fish skins have a significant potential for the production of high-quality gelatin with different melting and gelling temperatures over a much wider range than mammalian gelatins, yet still have a sufficiently high gel strength and viscosity. Gelatin quality is industrially determined by gel strength, viscosity, melting or gelling temperatures, the water content, and microbiological safety. For gelatin manufacturers, yield from a particular raw material is also important. Recent experimental studies have shown that these quality parameters vary greatly depending on the biochemical characteristics of the raw materials, the manufacturing processes applied, and the experimental settings used for quality control tests. In this review, the gelatin quality achieved from different fish species is reviewed along with the experimental procedures used to determine gelatin quality. In addition, the chemical structure of collagen and gelatin, the collagen-gelatin conversion, the gelation process, and the gelatin market are discussed. Copyright © 2010 Elsevier Inc. All rights reserved.

  2. 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.

  3. Characterization and comparison of methacrylic acid with 2-acrylamido-2-methyl-1-propanesulfonic acid in the preparation of monolithic column for capillary electrochromatography.

    PubMed

    Horiguchi, Daisuke; Ohyama, Kaname; Masunaga, Tomoko; Fujita, Yoshiko; Ali, Marwa Fathy Bakr; Kishikawa, Naoya; Kuroda, Naotaka

    2013-01-01

    Butyl methacrylate (BMA)-ethylene dimethacrylate (EDMA)-methacrylic acid (MAA) and BMA-EDMA-2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS) monolithic columns were prepared by varying the percentage of ionic monomers for capillary electrochromatography. Monolithic columns with a higher content of ionic monomers provided better column efficiency, and the performance of BMA-EDMA-MAA monoliths was better than BMA-EDMA-AMPS. To characterize and optimize BMA-EDMA-MAA monoliths, the effects of the content of cross-linker and the total monomer in the polymerization mixture on column performance were also studied. Plate heights of 8.2 µm for the unretained solute (thiourea) and 12.6 µm for the retained solute (naphthalene) were achieved with a monolithic column using 2.5% MAA (Column I).

  4. Cross-Linkable Gelatins with Superior Mechanical Properties Through Carboxylic Acid Modification: Increasing the Two-Photon Polymerization Potential.

    PubMed

    Van Hoorick, Jasper; Gruber, Peter; Markovic, Marica; Tromayer, Maximilian; Van Erps, Jürgen; Thienpont, Hugo; Liska, Robert; Ovsianikov, Aleksandr; Dubruel, Peter; Van Vlierberghe, Sandra

    2017-10-09

    The present work reports on the development of photo-cross-linkable gelatins sufficiently versatile to overcome current biopolymer two-photon polymerization (2PP) processing limitations. To this end, both the primary amines as well as the carboxylic acids of gelatin type B were functionalized with photo-cross-linkable moieties (up to 1 mmol/g) resulting in superior and tunable mechanical properties (G' from 5000 to 147000 Pa) enabling efficient 2PP processing. The materials were characterized in depth prior to and after photoinduced cross-linking using fully functionalized gelatin-methacrylamide (gel-MOD) as a benchmark to assess the effect of functionalization on the protein properties, cross-linking efficiency, and mechanical properties. In addition, preliminary experiments on hydrogel films indicated excellent in vitro biocompatibility (close to 100% viability) both in the presence of MC3T3 preosteoblasts and L929 fibroblasts. Moreover, 2PP processing of the novel derivative was superior in terms of applied laser power (≥40 vs ≥60 mW for gel-MOD at 100 mm/s) as well as post-production swelling (0-20% vs 75-100% for gel-MOD) compared to those of gel-MOD. The reported novel gelatin derivative (gel-MOD-AEMA) proves to be extremely suitable for direct laser writing as both superior mimicry of the applied computer-aided design (CAD) was obtained while maintaining the desired cellular interactivity of the biopolymer. It can be anticipated that the present work will also be applicable to alternative biopolymers mimicking the extracellular environment such as collagen, elastin, and glycosaminoglycans, thereby expanding current material-related processing limitations in the tissue engineering field.

  5. Preparation and characterization of gelatin/hyaluronic acid cryogels for adipose tissue engineering: in vitro and in vivo studies.

    PubMed

    Chang, Kun-Hung; Liao, Han-Tsung; Chen, Jyh-Ping

    2013-11-01

    Macroporous elastic scaffolds containing gelatin (4% or 10%) and 0.25% hyaluronic acid (HA) were fabricated by cryogelation for application in adipose tissue engineering. These cryogels have interconnected pores (∼200 μm), high porosity (>90%) and a high degree of cross-linking (>99%). The higher gelatin concentration reduced the pore size, porosity and swelling ratio of the cryogel but improved its swelling kinetics. Compressive mechanical testing of cryogel samples demonstrated non-linear stress-strain behavior and hysteresis loops during loading-unloading cycles, but total recovery from large strains. The presence of more gelatin increased the elastic modulus, toughness and storage modulus and yielded a cryogel that was highly elastic, with a loss tangent equal to 0.03. Porcine adipose-derived stem cells (ADSCs) were seeded in the cryogel scaffolds to assess their proliferation and differentiation. In vitro studies demonstrated a good proliferation rate and the adipogenic differentiation of the ADSCs in the cryogel scaffolds, as shown by their morphological change from a fibroblast-like shape to a spherical shape, decreased actin cytoskeleton content, growth arrest, secretion of the adipogenesis marker protein leptin, Oil Red O staining for triglycerides and expression of early (LPL and PPARγ) and late (aP2 and leptin) adipogenic marker genes. In vivo studies of ADSCs/cryogel constructs implanted in nude mice and pigs demonstrated adipose tissue and new capillary formation, the expression of PPARγ, leptin and CD31 in immunostained explants, and the continued expression of adipocyte-specific genes. Both the in vitro and in vivo studies indicated that the gelatin/HA cryogel provided a structural and chemical environment that enabled cell attachment and proliferation and supported the biological functions and adipogenesis of the ADSCs. Copyright © 2013 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  6. A strong inorganic acid-initiated methacrylate polymerization strategy for room temperature preparation of monolithic columns for capillary electrochromatography.

    PubMed

    Wang, Man-Man; Wang, He-Fang; Jiang, Dong-Qing; Wang, Shan-Wei; Yan, Xiu-Ping

    2010-05-01

    A facile strong inorganic acid-initiated methacrylate polymerization strategy was developed for fabricating monolithic columns at room temperature. The prepared monoliths were characterized by FTIR spectrometry, mercury intrusion porosimeter and SEM, while their performance was evaluated by CEC for the separation of various types of compounds including alkyl benzenes, polycyclic aromatic hydrocarbons, nonsteroidal anti-inflammatory drugs, anilines, and nitrophenol isomers. The column-to-column and batch-to-batch reproducibility for the prepared monoliths in terms of the RSD of EOF flow velocity, retention factor, and the minimum plate height of naphthalene ranged from 3.4 to 12.4%. The fabricated monoliths gave excellent performance for the separation of the test neutral compounds with the theoretical plates of 170,000-232,000 plates per meter for thiourea, and 77,400-112,300 plates per meter for naphthalene. The proposed strong inorganic acid-initiated methacrylate polymerization strategy is a promising alternative for fabricating organic polymer-based monoliths.

  7. Synthesis and characterization of new composite materials based on poly(methacrylic acid) and hydroxyapatite with applications in dentistry.

    PubMed

    Cucuruz, Andrei Tiberiu; Andronescu, Ecaterina; Ficai, Anton; Ilie, Andreia; Iordache, Florin

    2016-08-30

    The use of methacrylic acid (MAA) in medicine was poorly investigated in the past but can be of great importance because the incorporation of hydroxyapatite (HA) can lead to new composite materials with good properties due to the strong electrostatic interactions between carboxylate groups of polymer and Ca(2+) ions from HA. The scope of this study was to determine the potential of using composite materials based on poly(methacrylic acid) (PMAA) and hydroxyapatite in dentistry. Two routes of synthesis were taken into account: i) HA was synthesised in situ and ii) commercial HA was used. Fourier transform infrared spectroscopy and X-ray diffraction were used for compositional assessments. Scanning electron microscopy was performed to determine the morphology and differential thermal analysis (DTA) coupled with thermogravimetric analysis (TG) was used to study the thermal behaviour and to observe quantitative changes. In-vitro tests were also performed in order to evaluate the biocompatibility of both PMAA/HA composites by monitoring the development potential of human endothelial cells using MTT assay and fluorescent microscopy. Copyright © 2016 Elsevier B.V. All rights reserved.

  8. Synthesis and characterization of methacrylic derivatives of 5-amino salicylic acid with pH-sensitive swelling properties.

    PubMed

    Davaran, S; Rashidi, M R; Hashemi, M

    2001-12-03

    The purpose of this study is to develop novel colon-specific drug delivery systems with pH-sensitive swelling and drug release properties. Methacrylic-type polymeric prodrugs with different content levels of 5-amino salicylic acid (5-ASA) were synthesized by free radical copolymerization of metacrylic acid (MAA), polyethylene glycol monomethacrylate (PEGMA), and a methacrylic derivative of 5-ASA (methacryloyloxyethyl 5-amino salicylate [MOES]). The copolymers were characterized, and the drug content of the copolymers was determined. The effect of copolymer composition on the swelling behavior and hydrolytic degradation was studied in simulated gastric fluid (SGF, pH 1.2) and simulated intestinal fluid (SIF, pH 7.2). The swelling and hydrolytic behavior of the copolymers was dependent on the content of MAA groups and caused a decrease in gel swelling in SGF or an increase in gel swelling in SIF. Drug release studies showed that increasing content of MAA in the copolymer enhances the hydrolysis in SIF but has no effect in SGF. The results suggest that hydrogen-bonded complexes are formed between MAA and PEG pendant groups and that these pH-sensitive systems could be useful for preparation of a controlled-release formulation of 5-ASA.

  9. Fabrication and characterization of Sb-doped Sn02 thin films derived from methacrylic acid modified tin(IV)alkoxides

    NASA Astrophysics Data System (ADS)

    Kololuoma, Terho K.; Tolonen, Ari; Johansson, Leena-Sisko; Campbell, Joseph M.; Karkkainen, Ari H. O.; Hiltunen, Marianne; Haatainen, Tomi; Rantala, Juha T.

    2002-10-01

    We report on the fabrication of transparent, conductive and directly photopatternable, pure and Sb-doped tin dioxide thin films. Precursors used were antimony(III)isopropoxide and a photo-reactive tin alkoxide synthesized from tin(IV)isopropoxide and methacrylic acid. The synthesis of methacrylic acid modified tin alkoxide was monitored in-situ using IR- and ESI-TOF mass spectroscopic techniques. Sb-doped organo-tin films were deposited via single layer spin coating. After deposition the films were patterned via photopolymerization, using a mercury I-line UV-lamp. All investigated materials could be patterned with 3 μm features. After development in isopropanol, the films were annealed in air, in order to obtain crystalline and conductive films. The electrical conductivities of the annealed thin films with, and without, UV-irradiation were determined using a linear four-point method. The direct photopatterning process was found to increase the film conductivity for all the Sb-doping levels tested. The mechanisms for the increased conductivity were characterized using AFM, XPS and XRD techniques.

  10. 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.

  11. Continuous process of preparation of n-butyl(meth)acrylate by esterification of (meth)acrylic acid by butanol on thermostable sulfo-cation exchanger

    SciTech Connect

    Zheleznaya, L.L.; Karakhanov, R.A.; Lunin, A.F.; Magadov, R.S.; Meshcheryakov, S.V.; Mkrtychan, V.R.; Fomin, V.A.

    1987-11-10

    The authors propose an effective thermostable sulfo-cation exchanger based on polymers with a system of conjugated bonds, sulfopolyphenylene ketone (SPP) differing from the known cation exchangers by the high thermostability (up to 250/sup 0/C), and also having the effect of the stabilization of the double bond in unsaturated monomers. The combination of inhibiting and cation exchange properties makes it also possible to use these sulfo-cation exchangers in the processes of esterification of (meth)acrylic acids by alcohols without addition of special inhibitors. The SPP catalyst was tested in esterification processes of acrylic an methacrylic acid by butanol at a pilot plant.

  12. Contribution of the net charge to the regulatory effects of amino acids and epsilon-poly(L-lysine) on the gelatinization behavior of potato starch granules.

    PubMed

    Ito, Azusa; Hattori, Makoto; Yoshida, Tadashi; Takahashi, Koji

    2006-01-01

    The effects of lysine (Lys), monosodium glutamate (GluNa), glycine, alanine and epsilon-poly(L-lysine) (PL) with different degrees of polymerization on the gelatinization behavior of potato starch granules were investigated by DSC, viscosity and swelling measurements, microscopic observation, and measurement of the retained amino acid amount to clarify the contribution of the net charge to their regulatory effects on the gelatinization behavior. The amino acids and PL each contributed to an increase in the gelatinization temperature, and a decrease in the peak viscosity and swelling. These effects strongly depended on the absolute value of their net charge. The disappearance of a negative or positive net charge by adjusting the pH value weakened the contribution. The swelling index and size of the potato starch granules changed according to replacement of the swelling medium. The amino acids and PL were easily retained by the swollen potato starch granules according to replacement of the outer solution of the starch granules.

  13. PCL-gelatin composite nanofibers electrospun using diluted acetic acid-ethyl acetate solvent system for stem cell-based bone tissue engineering.

    PubMed

    Binulal, N S; Natarajan, Amrita; Menon, Deepthy; Bhaskaran, V K; Mony, Ullas; Nair, Shantikumar V

    2014-01-01

    Composite nanofibrous scaffolds with various poly(ε-caprolactone) (PCL)/gelatin ratios (90:10, 80:20, 70:30, 60:40, 50:50 wt.%) were successfully electrospun using diluted acetic and ethyl acetate mixture. The effects of this solvent system on the solution properties of the composites and its electrospinning properties were investigated. Viscosity and conductivity of the solutions, with the addition of gelatin, allowed for the electrospinning of uniform nanofibers with increasing hydrophilicity and degradation. Composite nanofibers containing 30 and 40 wt.% gelatin showed an optimum combination of hydrophilicity and degradability and also maintained the structural integrity of the scaffold. Human mesenchymal stem cells (hMSCs) showed favorable interaction with and proliferation on, the composite scaffolds. hMSC proliferation was highest in the 30 and 40 wt.% gelatin containing composites. Our experimental data suggested that PCL-gelatin composite nanofibers containing 30-40 wt.% of gelatin and electrospun in diluted acetic acid-ethyl acetate mixture produced nanofiber scaffolds with optimum hydrophilicity, degradability, and bio-functionality for stem cell-based bone tissue engineering.

  14. Methyl methacrylate

    Integrated Risk Information System (IRIS)

    TOXICOLOGICAL REVIEW of METHYL METHACRYLATE ( CAS No . 80 - 62 - 6 ) In Support of Summary Information on the Integrated Risk Information System ( IRIS ) January 1998 U.S . Environmental Protection Agency Washington , DC TABLE OF CONTENTS DISCLAIMER . . . . . . . . . . . . . . . . . . . . . . . . .

  15. Production of a composite hyaluronic acid/gelatin blood plasma gel for hydrogel-based adipose tissue engineering applications.

    PubMed

    Korurer, Esra; Kenar, Halime; Doger, Emek; Karaoz, Erdal

    2014-07-01

    Standard approaches to soft-tissue reconstruction include autologous adipose tissue transplantation, but most of the transferred adipose tissue is generally reabsorbed in a short time. To overcome this problem, long lasting implantable hydrogel materials that can support tissue regeneration must be produced. The purpose of this study was to evaluate the suitability of composite 3D natural origin scaffolds for reconstructive surgery applications through in vitro tests. The Young's modulus of the glutaraldehyde crosslinked hyaluronic acid/gelatin (HA/G) plasma gels, composed of human platelet-poor plasma, gelatin and human umbilical cord hyaluronic acid, was determined as 3.5 kPa, close to that of soft tissues. The composite HA/G plasma gels had higher porosity than plain plasma gels (72.5% vs. 63.86%). Human adipose tissue derived stem cells (AD-MSCs) were isolated from human lipoaspirates and characterized with flow cytometry, and osteogenic and adipogenic differentiation. Cell proliferation assay of AD-MSCs on the HA/G plasma gels revealed the nontoxic nature of these constructs. Adipogenic differentiation was distinctly better on HA/G plasma gels than on plain plasma gels. The results showed that the HA/G plasma gel with its suitable pore size, mechanical properties and excellent cell growth and adipogenesis supporting properties can serve as a useful scaffold for adipose tissue engineering applications.

  16. Designing novel macroporous composite hydrogels based on methacrylic acid copolymers and chitosan and in vitro assessment of lysozyme controlled delivery.

    PubMed

    Dragan, Ecaterina Stela; Cocarta, Ana Irina; Gierszewska, Magdalena

    2016-03-01

    Designing structure and morphology of macroporous hydrogels is crucial for their applications in controlled release systems of macromolecular drugs. Macroporous hydrogels, consisting of methacrylic acid (MAA) and either acryl amide (AAm) or 2-hydroxyethyl methacrylate (HEMA) (1st network), were prepared for this purpose by cryogelation (single network cryogels, SNCs). Macroporous interpenetrating polymer network (IPN) hydrogel composites were then prepared by a sequential strategy, the 2nd network consisting of chitosan (CS) cross-linked with poly(ethyleneglycol) diglycidyl ether (PEGDGE) being generated by the sorption of a CS and PEGDGE mixture in the 1st network followed by cross-linking. A strong difference in the behavior of SNCs and IPN hydrogel composites was found during the loading and release of lysozyme (LYS) used as macromolecular drug model. Thus, while the amount of LYS loaded on SNCs was higher than that loaded on the IPNs, the release of LYS from SNCs occurred at pH 2, when the ratio between MAA and AAm was 50:50, and only at pH 1 when the ratio between MAA and AAm was 70:30. The 2nd network led to the decrease of the pore size of the IPNs, mainly when the initial concentration of monomers was 10wt/v%, but the presence of CS facilitates the LYS release from IPNs, mainly at a concentration of monomer of 5wt/v%, and when HEMA was used as nonionic comonomer.

  17. Use of Activated Carbon in Packaging to Attenuate Formaldehyde-Induced and Formic Acid-Induced Degradation and Reduce Gelatin Cross-Linking in Solid Dosage Forms.

    PubMed

    Colgan, Stephen T; Zelesky, Todd C; Chen, Raymond; Likar, Michael D; MacDonald, Bruce C; Hawkins, Joel M; Carroll, Sophia C; Johnson, Gail M; Space, J Sean; Jensen, James F; DeMatteo, Vincent A

    2016-07-01

    Formaldehyde and formic acid are reactive impurities found in commonly used excipients and can be responsible for limiting drug product shelf-life. Described here is the use of activated carbon in drug product packaging to attenuate formaldehyde-induced and formic acid-induced drug degradation in tablets and cross-linking in hard gelatin capsules. Several pharmaceutical products with known or potential vulnerabilities to formaldehyde-induced or formic acid-induced degradation or gelatin cross-linking were subjected to accelerated stability challenges in the presence and absence of activated carbon. The effects of time and storage conditions were determined. For all of the products studied, activated carbon attenuated drug degradation or gelatin cross-linking. This novel use of activated carbon in pharmaceutical packaging may be useful for enhancing the chemical stability of drug products or the dissolution stability of gelatin-containing dosage forms and may allow for the 1) extension of a drug product's shelf-life when the limiting attribute is a degradation product induced by a reactive impurity, 2) marketing of a drug product in hotter and more humid climatic zones than currently supported without the use of activated carbon, and 3) enhanced dissolution stability of products that are vulnerable to gelatin cross-linking.

  18. UV irradiation enhances the bonding strength between citric acid-crosslinked gelatin and stainless steel.

    PubMed

    Inoue, Motoki; Sasaki, Makoto; Katada, Yasuyuki; Taguchi, Tetsushi

    2011-11-01

    The effect of ultraviolet ray (UV) irradiation on the bonding strength between low carbon stainless steel 316 (SUS316L) and trisuccinimidyl citrate (TSC)-crosslinked alkali-treated gelatin (AlGelatin-TSC) was investigated. The UV irradiation effectively generated hydroxyl groups on the surface of SUS316L. The bonding strength between AlGelatin-TSC and SUS316L before UV irradiation was 0.345±0.007 MPa, and upon UV irradiation it increased to 0.750±0.069 MPa. In order to explain this enhanced bonding strength, the surface of SUS316L was examined using its water contact angle and X-ray photoelectron spectroscopy. Furthermore, the N 1s peaks derived from the TSC succinimidyl group were assigned to the surface of SUS316L after the immobilization of the TSC. This indicates that ester bond formation between the TSC active esters and the SUS316L hydroxyl groups contributed to the enhanced bonding strength. Therefore, UV irradiation and subsequent TSC immobilization is a simple way to functionalize biometal surfaces with various structures. This has practical applications for medical devices such as drug-eluting stents, dental implants, and metallic artificial bone.

  19. Synthesis and characterization of poly(methoxyl ethylene glycol-caprolactone-co-methacrylic acid-co-poly(ethylene glycol) methyl ether methacrylate) pH-sensitive hydrogel for delivery of dexamethasone.

    PubMed

    Wang, Ke; Xu, Xu; Wang, YuJun; Yan, Xi; Guo, Gang; Huang, MeiJuan; Luo, Feng; Zhao, Xia; Wei, YuQuan; Qian, ZhiYong

    2010-04-15

    In this work, a novel pH-sensitive hydrogels based on macromonomer of methoxyl poly(ethylene glycol)-poly(caprolactone)-acryloyl chloride (MPEG-PCL-AC, PCE-AC), poly(ethylene glycol) methyl ether methacrylate (MPEGMA), and methacrylic acid (MAA) were successfully synthesized by heat-initiated free radical polymerization method. The obtained macromonomers and hydrogels were characterized by (1)H NMR and FT-IR, respectively. Morphology study, swelling behavior, in vitro drug release behavior, acute oral toxicity of hydrogels, and cytotoxicity of PCE-AC macromonomer were also investigated in this paper. Finally, the hydrogels demonstrated that the sharp change in different pH value, thus believing to be promising the suitability of the candidate for oral drug-delivery systems.

  20. Photochemical process in dichromated photosensitive material: dichromated (polyvinyl alcohol-polyacrylic acid)-- a model for dichromated gelatin?

    NASA Astrophysics Data System (ADS)

    Bolte, Michel; Lessard, Roger A.; Pizzocaro, Christine

    2003-02-01

    Gelatin (G) can be described as a peptidic chain with different pendent groups among which, hydroxy groups-OH, carboxylic groups-COOH and amino groups -NH2. Works performed on polyacrylic acid (PAA), a poymeric chain with only pendent-COOH group and on polyvinyl alcohol (PVA) with only -OH group revelaed the strong influence of the nature of the chemical structure on the photochemical behavior of dichromated photopolymers, DCG, DCPAA and DCPVA. Actually, the stability and the state of complexation of the different chromium species was completely opposite in the two matrices: the stabilization of chromium (V) resulting from the photochemical charge transfer in DCPVA, by complexation with PVA is in contrast to what was observed in DCPAA where chromium (V) was highly instable. Regarding chromium (III), the final reduction chromium species, it is complexed in PAA and not in PVA. The primary proces is identical in DCG and in DCPVA, so PVA appears as a good model of the first step of gelatin behavior. But the material obtained after irradiation and treatment of DCG only contains chromium strongly complexed by gelatin. The experiments performed on films of DC with only a few percents of PAA gave evidence for the strong influence of the presence of the carboxylic groups on the photochemical behavior: the rate of the formation and the stability of chromium species, mainly chromium (V), involved in the process. Chromium (V) appears to play a key role in the photosensitive properties of dichromated materials. The diffraction efficiencies of holograms recorded in DCPAA or DCPVA resemble the profiles of chromium (V) evolution.

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

    PubMed

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

    2016-01-01

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

  2. Preparation of poly(polyethylene glycol methacrylate-co-acrylic acid) hydrogels by radiation and their physical properties

    NASA Astrophysics Data System (ADS)

    Park, Sung-Eun; Nho, Young-Chang; Kim, Hyung-Il

    2004-02-01

    The pH-responsive copolymer hydrogels were prepared with the monomers of polyethylene glycol methacrylate and acrylic acid based on γ-ray irradiation technique. The gel content of these copolymer hydrogels varied depending on both the composition of monomers and the radiation dose. Maximum gel percent and degree of crosslinking were obtained at the composition of equal amount of comonomers. These copolymer hydrogels did not show any noticeable change in swelling at lower pH range. However they showed an abrupt increase in swelling at higher pH range due to the ionization of carboxyl groups. This pH-responsive swelling behavior was applied for the insulin carrier via oral delivery. Insulin-loaded copolymer hydrogels released most of their insulin in the simulated intestinal fluid which had a pH of 6.8 but not in the simulated gastric fluid which had a pH of 1.2.

  3. Swelling and thermodynamic studies of temperature responsive 2-hydroxyethyl methacrylate/itaconic acid copolymeric hydrogels prepared via gamma radiation

    NASA Astrophysics Data System (ADS)

    Tomić, Simonida L. J.; Mićić, Maja M.; Filipović, Jovanka M.; Suljovrujić, Edin H.

    2007-08-01

    The copolymeric hydrogels based on 2-hydroxyethyl methacrylate (HEMA) and itaconic acid (IA) were synthesized by gamma radiation induced radical polymerization. Swelling and thermodynamic properties of PHEMA and copolymeric P(HEMA/IA) hydrogels with different IA contents (2, 3.5 and 5 mol%) were studied in a wide pH and temperature range. Initial studies of so-prepared hydrogels show interesting pH and temperature sensitivity in swelling and drug release behavior. Special attention was devoted to temperature investigations around physiological temperature (37 °C), where small changes in temperature significantly influence swelling and drug release of these hydrogels. Due to maximum swelling of hydrogels around 40 °C, the P(HEMA/IA) hydrogel containing 5 mol% of IA without and with drug-antibiotic (gentamicin) were investigated at pH 7.40 and in the temperature range 25-42 °C, in order to evaluate their potential for medical applications.

  4. Chitosan microsphere scaffold tethered with RGD-conjugated poly(methacrylic acid) brushes as effective carriers for the endothelial cells.

    PubMed

    Yang, Zhenyi; Yuan, Shaojun; Liang, Bin; Liu, Yang; Choong, Cleo; Pehkonen, Simo O

    2014-09-01

    Endothelial cell-matrix interactions play a vital role in promoting vascularization of engineered tissues. The current study reports a facile and controllable method to develop a RGD peptide-functionalized chitosan microsphere scaffolds for rapid cell expansion of human umbilical vein endothelial cells (HUVECs). Functional poly(methacrylic acid) (PMAA) brushes are grafted from the chitosan microsphere surfaces via surface-initiated ATRP. Subsequent conjugation of RGD peptides on the pendent carboxyl groups of PMAA side chain is accomplished by carbodiimide chemistry to facilitate biocompatibility of the 3D CS scaffolding system. In vitro cell-loading assay of HUVECs exhibits a significant improvment of cell adhesion, spreading, and proliferation on the RGD peptide-immobilized CS microsphere surfaces.

  5. Composite particles formed by complexation of poly(methacrylic acid) - stabilized magnetic fluid with chitosan: Magnetic material for bioapplications.

    PubMed

    Safarik, Ivo; Stepanek, Miroslav; Uchman, Mariusz; Slouf, Miroslav; Baldikova, Eva; Nydlova, Leona; Pospiskova, Kristyna; Safarikova, Mirka

    2016-10-01

    A simple procedure for the synthesis of magnetic fluid (ferrofluid) stabilized by poly(methacrylic acid) has been developed. This ferrofluid was used to prepare a novel type of magnetically responsive chitosan-based composite material. Both ferrofluid and magnetic chitosan composite were characterized by a combination of microscopy (optical microscopy, TEM, SEM), scattering (static and dynamic light scattering, SANS) and spectroscopy (FTIR) techniques. Magnetic chitosan was found to be a perspective material for various bioapplications, especially as a magnetic carrier for immobilization of enzymes and cells. Lipase from Candida rugosa was covalently attached after cross-linking and activation of chitosan using glutaraldehyde. Baker's yeast cells (Saccharomyces cerevisiae) were incorporated into the chitosan composite during its preparation; both biocatalysts were active after reaction with appropriate substrates.

  6. Density Functional Theory (DFT) Study of Molecularly Imprinted Polymer (MIP) Methacrylic Acid (MAA) with D-Glucose

    NASA Astrophysics Data System (ADS)

    Wungu, T. D. K.; Marsha, S. E.; Widayani; Suprijadi

    2017-07-01

    In order to find an alternative biosensor material which enables to detect the glucose level, therefore in this study, the interaction between Methacrylic Acid (MAA) based Molecularly Imprinted Polymer (MIP) with D-Glucose is investigated using the Density Functional Theory (DFT). The aim of this study is to determine whether a molecule of the MAA can be functioned as a bio-sensing of glucose. In this calculation, the Gaussian 09 with B3LYP and 631+G(d) basis sets is used to calculate all electronic properties. It is found that the interaction between a molecule of MAA and a molecule of D-Glucose was observed through the shortened distance between the two molecules. The binding energy of MAA/D-glucose and the Mulliken population analysis are investigated for checking possible interaction. From analysis, the MAA based MIP can be used as a bio-sensing material.

  7. Efficient gas barrier properties of multi-layer films based on poly(lactic acid) and fish gelatin.

    PubMed

    Hosseini, Seyed Fakhreddin; Javidi, Zahra; Rezaei, Masoud

    2016-11-01

    Multi-layer film structures of poly(lactic acid) (PLA) and fish gelatin (FG), prepared using the solvent casting technique, were studied in an effort to produce bio-based films with low oxygen (OP) and water vapor permeability (WVP). The scanning electron microscopy (SEM) images of triple-layer film showed that the outer PLA layers are being closely attached to the inner FG layer to make continuous film. The OP of multi-layer film (5.02cm(3)/m(2)daybar) decreased more than 8-fold compared with that of the PLA film, and the WVP of multi-layer film (0.125gmm/kPah m(2)) also decreased 11-fold compared with that of the FG film. Lamination with PLA profoundly increased the water resistance of the bare gelatin film. Meanwhile, the tensile strength of the triple-layer film (25±2.13MPa) was greater than that of FG film (7.48±1.70MPa). At the same time, the resulting film maintains high optical clarity. Differential scanning calorimetry (DSC) analysis also revealed that the materials were compatible showing only one Tg which decreased with FG deposition. This material exhibits an environmental-friendliness potential and a high versatility in food packaging. Copyright © 2016 Elsevier B.V. All rights reserved.

  8. Gelatin-poly(lactic-co-glycolic acid) scaffolds with oriented pore channel architecture - From in vitro to in vivo testing.

    PubMed

    Thiem, A; Bagheri, M; Große-Siestrup, C; Zehbe, R

    2016-05-01

    A gelatin-poly(lactic-co-glycolic acid), PLGA, composite scaffold, featuring a highly oriented pore channel structure, was developed as a template for articular cartilage regeneration. As a design principle the composite scaffold was optimized to contain only medical grade educts and accordingly no chemical cross linking agents or other toxicological relevant substances or methods were used. Scaffolds were synthesized using a freeze structuring method combined with an electrochemical process followed by freeze-drying. Finally, cross linking was performed using dehydrothermal treatment, which was simultaneously used for sterilization purposes. These composite scaffolds were analyzed in regard to structural and biomechanical properties, and to their degradation behavior. Furthermore, cell culture performance was tested using chondrocytes originated from joint articular cartilage tissue from 6 to 10 months old domestic pigs. Finally, the scaffolds were tested for tissue biocompatibility and their ability for tissue integration in a rat model. The scaffolds showed both excellent functional performance and high biocompatibility in vitro and in vivo. We expect that these gelatin-PLGA scaffolds can effectively support chondrogenesis in vivo demonstrating great potential for the use in cartilage defect treatment.

  9. Encapsulation of lycopene extract from tomato pulp waste with gelatin and poly(gamma-glutamic acid) as carrier.

    PubMed

    Chiu, Y T; Chiu, C P; Chien, J T; Ho, G H; Yang, J; Chen, B H

    2007-06-27

    Tomato pulp waste, a byproduct obtained during the processing of tomato juice, has been shown to be a rich source of lycopene. The objectives of this study were to use gelatin and poly(gamma-glutamic acid) (gamma-PGA) as coating materials for the encapsulation of lycopene extract from tomato pulp waste. Initially, lycopene was extracted with supercritical carbon dioxide, followed by microencapsulation using an emulsion system consisting of 4.5% gelatin, 10% gamma-PGA, and 4.8% lycopene extract. Analysis of differential scanning calorimetry revealed that the thermal stability of the coating material could be up to 120 degrees C, with a mean particle size of 38.7 microm based on Coulter counter analysis. The total weight of microencapsulated powder was 617 microg with the yield of lycopene being 76.5%, indicating a 23.5% loss during freeze drying. During storage of microencapsulated powder, the concentrations of cis-, trans-, and total lycopene decreased along with increasing time and temperature. A fast release of lycopene in the powder occurred at pH 5.5 and 7.0, while no lycopene was released at pH 2.0 and 3.5.

  10. Designing a gelatin/chitosan/hyaluronic acid biopolymer using a thermophysical approach for use in tissue engineering.

    PubMed

    Enrione, Javier; Díaz-Calderón, Paulo; Weinstein-Oppenheimer, Caroline R; Sánchez, Elizabeth; Fuentes, Miguel A; Brown, Donald I; Herrera, Hugo; Acevedo, Cristian A

    2013-12-01

    Cell culture on biopolymeric scaffolds has provided treatments for tissue engineering. Biopolymeric mixtures based on gelatin (Ge), chitosan (Ch) and hyaluronic acid (Ha) have been used to make scaffolds for wound healing. Thermal and physical properties of scaffolds prepared with Ge, Ch and Ha were characterized. Thermal characterization was made by using differential scanning calorimetry (DSC), and physical characterization by gas pycnometry and scanning electron microscopy. The effects of Ge content and cross-linking on thermophysical properties were evaluated by means of a factorial experiment design (central composite face centered). Gelatin content was the main factor that affects the thermophysical properties (microstructure and thermal transitions) of the scaffold. The effect of Ge content of the scaffolds for tissue engineering was studied by seeding skin cells on the biopolymers. The cell attachment was not significantly modified at different Ge contents; however, the cell growth rate increased linearly with the decrease of the Ge content. This relationship together with the thermophysical characterization may be used to design scaffolds for tissue engineering.

  11. Magnetic pH-responsive poly(methacrylic acid-co-acrylic acid)-co-polyvinylpyrrolidone magnetic nano-carrier for controlled delivery of fluvastatin.

    PubMed

    Amoli-Diva, Mitra; Pourghazi, Kamyar; Mashhadizadeh, Mohammad Hossein

    2015-02-01

    A novel pH-responsive polymer, poly(methacrylic acid-co-acrylic acid)-co-polyvinyl-pyrrolidone (polymeric nano-carrier) was synthesized and used for encapsulation of 3-aminopropyl triethoxysilane modified Fe3O4 nanoparticles to prepare a new magnetic nano-carrier. The loading and release characteristics of both polymeric and magnetic nano-carriers were investigated using fluvastatin as the model drug. The loading behavior of the carriers was studied by varying concentration of fluvastatin in aqueous medium at 25°C and their release was followed spectrophotometrically (at 304 nm) at 37°C in three different solutions (buffered at pH1.2, 5.5 and 7.2) to simulate gastric and intestine medium. The effect of different parameters on the release of fluvastatin such as the amount of methacrylic acid monomer, cross-linker amount, initiator amount, and magnetic nanoparticles content was also studied. Considering the release kinetics and mechanism of the magnetic nanocarrier besides swelling behavior study of the polymeric nano-carrier reveal Fickian pattern and diffusion controlled mechanism for delivery of fluvastatin.

  12. Starch gelatinization.

    PubMed

    Ratnayake, Wajira S; Jackson, David S

    2009-01-01

    Starch occurs as highly organized structures, known as starch granules. Starch has unique thermal properties and functionality that have permitted its wide use in food products and industrial applications. When heated in water, starch undergoes a transition process, during which the granules break down into a mixture of polymers-in-solution, known as gelatinization. The sequence of structural transformations that the starch granule undergoes during this order-to-disorder transition has been extensively researched. None of the published starch gelatinization theories can fully and adequately explain the exact mechanism of sequential structural changes that starch granules undergo during gelatinization. This chapter analyzes several published theories and summarizes our current understanding of the starch gelatinization process.

  13. An In Vivo Study of Composite Microgels Based on Hyaluronic Acid and Gelatin for the Reconstruction of Surgically Injured Rat Vocal Folds

    ERIC Educational Resources Information Center

    Coppoolse, Jiska M. S.; Van Kooten, T. G.; Heris, Hossein K.; Mongeau, Luc; Li, Nicole Y. K.; Thibeault, Susan L.; Pitaro, Jacob; Akinpelu, Olubunm; Daniel, Sam J.

    2014-01-01

    Purpose: The objective of this study was to investigate local injection with a hierarchically microstructured hyaluronic acid-gelatin (HA-Ge) hydrogel for the treatment of acute vocal fold injury using a rat model. Method: Vocal fold stripping was performed unilaterally in 108 Sprague-Dawley rats. A volume of 25 µl saline (placebo controls),…

  14. An In Vivo Study of Composite Microgels Based on Hyaluronic Acid and Gelatin for the Reconstruction of Surgically Injured Rat Vocal Folds

    ERIC Educational Resources Information Center

    Coppoolse, Jiska M. S.; Van Kooten, T. G.; Heris, Hossein K.; Mongeau, Luc; Li, Nicole Y. K.; Thibeault, Susan L.; Pitaro, Jacob; Akinpelu, Olubunm; Daniel, Sam J.

    2014-01-01

    Purpose: The objective of this study was to investigate local injection with a hierarchically microstructured hyaluronic acid-gelatin (HA-Ge) hydrogel for the treatment of acute vocal fold injury using a rat model. Method: Vocal fold stripping was performed unilaterally in 108 Sprague-Dawley rats. A volume of 25 µl saline (placebo controls),…

  15. Ammonium methacrylate

    Integrated Risk Information System (IRIS)

    Ammonium methacrylate ; CASRN 16325 - 47 - 6 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcin

  16. Effect of tannic acid-fish scale gelatin hydrolysate hybrid nanoparticles on intestinal barrier function and α-amylase activity.

    PubMed

    Wu, Shao-Jung; Ho, Yi-Cheng; Jiang, Shun-Zhou; Mi, Fwu-Long

    2015-07-01

    Practical application of tannic acid is limited because it readily binds proteins to form insoluble aggregates. In this study, tannic acid was self-assembled with fish scale gelatin hydrolysates (FSGH) to form stable colloidal complex nanoparticles. The nanoparticles prepared from 4 mg ml(-1) tannic acid and 4 mg ml(-1) FSGH had a mean particle size of 260.8 ± 3.6 nm, and showed a positive zeta potential (20.4 ± 0.4 mV). The nanoparticles acted as effective nano-biochelators and free radical scavengers because they provided a large number of adsorption sites for interaction with heavy metal ions and scavenging free radicals. The maximum adsorption capacity for Cu(2+) ions was 123.5 mg g(-1) and EC50 of DPPH radical scavenging activity was 21.6 ± 1.2 μg ml(-1). Hydroxyl radical scavenging effects of the nanoparticles were investigated by electron spin resonance spectroscopy. The copper-chelating capacity and free radical scavenging activity of the nanoparticles were associated with their capacity to inhibit Cu(2+) ion-induced barrier impairment and hyperpermeability of Caco-2 intestinal epithelial tight junction (TJ). However, α-amylase inhibitory activity of the nanoparticles was significantly lower than that of free tannic acid. The results suggest that the nanoparticles can ameliorate Cu(2+) ion induced intestinal epithelial TJ dysfunction without severely inhibiting the activity of the digestive enzymes.

  17. Flocculation and adsorption properties of biodegradable gum-ghatti-grafted poly(acrylamide-co-methacrylic acid) hydrogels.

    PubMed

    Mittal, H; Jindal, R; Kaith, B S; Maity, A; Ray, S S

    2015-01-22

    This study reports the microwave-assisted synthesis of gum-ghatti (Gg)-grafted poly(acrylamide-co-methacrylic acid) (AAm-co-MAA) hydrogels for the development of biodegradable flocculants and adsorbents. The synthesized hydrogels were characterized using TGA, FTIR and SEM. TGA studies revealed that the synthesized hydrogels were thermally more stable than pristine Gg and exhibited maximum swelling capacity of 1959% at 60°C in neutral pH. The optimal Gg-cl-P(AAm-co-MAA) hydrogel was successfully employed for the removal of saline water from various petroleum fraction-saline emulsions. The maximum flocculation efficiency was achieved in an acidic clay suspension with a 15 mg polymer dose at 40°C. Moreover, the synthesized hydrogel adsorbed 94% and 75% of Pb(2+) and Cu(2+), respectively, from aqueous solutions. Finally, the Gg-cl-P(AAm-co-MAA) hydrogel could be degraded completely within 50 days. In summary, the Gg-cl-P(AAm-co-MAA) hydrogel was demonstrated to have potential for use as flocculants and heavy metal absorbents for industrial waste water treatment. Copyright © 2014 Elsevier Ltd. All rights reserved.

  18. Swelling and drug release behavior of poly(2-hydroxyethyl methacrylate/itaconic acid) copolymeric hydrogels obtained by gamma irradiation

    NASA Astrophysics Data System (ADS)

    Tomić, S. Lj.; Mićić, M. M.; Filipović, J. M.; Suljovrujić, E. H.

    2007-05-01

    The new copolymeric hydrogels based on 2-hydroxyethyl methacrylate (HEMA) and itaconic acid (IA) were prepared by gamma irradiation, in order to examine the potential use of these hydrogels in controlled drug release systems. The influence of IA content in the gel on the swelling characteristics and the releasing behavior of hydrogels, and the effect of different drugs, theophylline (TPH) and fenethylline hydrochloride (FE), on the releasing behavior of P(HEMA/IA) matrix were investigated in vitro. The diffusion exponents for swelling and drug release indicate that the mechanisms of buffer uptake and drug release are governed by Fickian diffusion. The swelling kinetics and, therefore, the release rate depends on the matrix swelling degree. The drug release was faster for copolymeric hydrogels with a higher content of itaconic acid. Furthermore, the drug release for TPH as model drug was faster due to a smaller molecular size and a weaker interaction of the TPH molecules with(in) the P(HEMA/IA) copolymeric networks.

  19. Gelatin-based membrane containing usnic acid-loaded liposome improves dermal burn healing in a porcine model.

    PubMed

    Nunes, Paula Santos; Rabelo, Alessandra Silva; Souza, Jamille Cristina Campos de; Santana, Bruno Vasconcelos; da Silva, Thailson Monteiro Menezes; Serafini, Mairim Russo; Dos Passos Menezes, Paula; Dos Santos Lima, Bruno; Cardoso, Juliana Cordeiro; Alves, Júlio César Santana; Frank, Luiza Abrahão; Guterres, Sílvia Stanisçuaski; Pohlmann, Adriana Raffin; Pinheiro, Malone Santos; de Albuquerque, Ricardo Luiz Cavalcanti; Araújo, Adriano Antunes de Souza

    2016-11-20

    There are a range of products available which claim to accelerate the healing of burns; these include topical agents, interactive dressings and biomembranes. The aim of this study was to assess the effect of a gelatin-based membrane containing usnic acid/liposomes on the healing of burns in comparison to silver sulfadiazine ointment and duoDerme(®) dressing, as well as examining its quantification by high performance liquid chromatography. The quantification of the usnic acid/liposomes was examined using high performance liquid chromatography (HPLC) by performing separate in vitro studies of the efficiency of the biomembranes in terms of encapsulation, drug release and transdermal absorption. Then, second-degree 5cm(2) burn wounds were created on the dorsum of nine male pigs, assigned into three groups (n=3): SDZ - animals treated with silver sulfadiazine ointment; GDU - animals treated with duoDerme(®); UAL - animals treated with a gelatin-based membrane containing usnic acid/liposomes. These groups were treated for 8, 18 and 30days. In the average rate of contraction, there was no difference among the groups (p>0.05). The results of the quantification showed that biomembranes containing usnic acid/liposomes were controlled released systems capable of transdermal absorption by skin layers. A macroscopic assay did not observe any clinical signs of secondary infections. Microscopy after 8days showed hydropic degeneration of the epithelium, with intense neutrophilic infiltration in all three groups. At 18days, although epidermal neo-formation was only partial in all three groups, it was most incipient in the SDZ group. Granulation tissue was more exuberant and cellularized in the UAL and GDU groups. At 30days, observed restricted granulation tissue in the region below the epithelium in the GDU and UAL groups was observed. In the analysis of collagen though picrosirius, the UAL group showed greater collagen density. Therefore, the UAL group displayed development and

  20. Amperometric uric acid biosensor based on poly(vinylferrocene)-gelatin-carboxylated multiwalled carbon nanotube modified glassy carbon electrode.

    PubMed

    Erden, Pınar Esra; Kaçar, Ceren; Öztürk, Funda; Kılıç, Esma

    2015-03-01

    In this study, a new uric acid biosensor was constructed based on ferrocene containing polymer poly(vinylferrocene) (PVF), carboxylated multiwalled carbon nanotubes (c-MWCNT) and gelatin (GEL) modified glassy carbon electrode (GCE). Uricase enzyme (UOx) was immobilized covalently through N-ethyl-N'-(3-dimethyaminopropyl) carbodiimide (EDC) and N-hydroxyl succinimide (NHS) chemistry onto c-MWCNT/GEL/PVF/GCE. The c-MWCNT/GEL/PVF composite was characterized by scanning electron microscopy, cyclic voltammetry and electrochemical impedance spectroscopy. Various experimental parameters such as pH, applied potential, enzyme loading, PVF and c-MWCNT concentration were investigated in detail. Under the optimal conditions the dynamic linear range of uric acid was 2.0×10(-7) M-7.1×10(-4) M (R=0.9993) with the detection limit low to 2.3×10(-8) M. With good selectivity and sensitivity, the biosensor was successfully applied to determine the uric acid in human serum. The results of the biosensor were in good agreement with those obtained from standard method. Therefore, the presented biosensor could be a good promise for practical applications in real samples.

  1. Surface grafting of a thermoplastic polyurethane with methacrylic acid by previous plasma surface activation and by ultraviolet irradiation to reduce cell adhesion.

    PubMed

    Alves, P; Pinto, S; Kaiser, Jean-Pierre; Bruinink, Arie; de Sousa, Hermínio C; Gil, M H

    2011-02-01

    The material performance, in a biological environment, is mainly mediated by its surface properties and by the combination of chemical, physical, biological, and mechanical properties required, for a specific application. In this study, the surface of a thermoplastic polyurethane (TPU) material (Elastollan(®)1180A50) was activated either by plasma or by ultra-violet (UV) irradiation. After surface activation, methacrylic acid (MAA) was linked to the surface of TPU in order to improve its reactivity and to reduce cell adhesion. Grafted surfaces were evaluated by X-ray photoelectron spectroscopy (XPS), by atomic force microscopy (AFM) and by contact angle measurements. Blood compatibility studies and cell adhesion tests with human bone marrow cells (HBMC) were also performed. If was found that UV grafting method led to better results than the plasma activation method, since cell adhesion was reduced when methacrylic acid was grafted to the TPU surface by UV.

  2. Acid-base properties, deactivation, and in situ regeneration of condensation catalysts for synthesis of methyl methacrylate

    SciTech Connect

    Gogate, M.R.; Spivey, J.J.; Zoeller, J.R.

    1996-12-31

    Condensation reaction of a propionate with formaldehyde is a novel route for synthesis of methyl methacrylate (MMA). The reaction mechanism involves a proton abstraction from the propionate on the basic sites and activation of the aliphatic aldehyde on the acidic sites of the catalyst. The acid-base properties of ternary V-Si-P oxide catalysts and their relation to the NWA yield in the vapor phase condensation of formaldehyde with propionic anhydride has been studied for the first time. Five different V-Si-P catalysts with different atomic ratios of vanadium, silicon, and phosphorous were synthesized, characterized, and tested in a fixed-bed microreactor system. A V-Si-P 1:10:2.8 catalyst gave the maximum condensation yield of 56% based on HCHO fed at 300{degrees}C and 2 atm and at a space velocity of 290 cc/g cat{center_dot}h. A parameter called the ``q-ratio`` has been defined to correlate the condensation yields to the acid-base properties. The correlation of q-ratio with the condensation yield shows that higher q-ratios are more desirable. The long-term deactivation studies on the V-Si-P 1: 10:2.8 catalyst at 300{degrees}C and 2 atm and at a space velocity of 290 cc/g cat{center_dot}h show that the catalyst activity drops by a factor of nearly 20 over a 180 h period. The activity can be restored to about 78% of the initial activity by a mild oxidative regeneration at 300{degrees}C and 2 atm. The performance of V-Si-P catalyst has been compared to a Ta/SiO{sub 2} catalyst. The Ta- catalyst is more stable and has a higher on-stream catalyst life.

  3. Physicochemical characterization and mechanisms of release of theophylline from melt-extruded dosage forms based on a methacrylic acid copolymer.

    PubMed

    Young, Christopher R; Dietzsch, Caroline; Cerea, Matteo; Farrell, Thomas; Fegely, Kurt A; Rajabi-Siahboomi, Ali; McGinity, James W

    2005-09-14

    The purpose of the current study was to investigate the physicochemical properties of melt-extruded dosage forms based on Acryl-EZE and to determine the influence of gelling agents on the mechanisms and kinetics of drug release from thermally processed matrices. Acryl-EZE is a pre-mixed excipient blend based on a methacrylic acid copolymer that is optimized for film-coating applications. Powder blends containing theophylline, Acryl-EZE, triethyl citrate and an optional gelling agent, Methocel K4M Premium (hydroxypropyl methylcellulose, HPMC, hypromellose 2208) or Carbopol 974P (carbomer), were thermally processed using a Randcastle single-screw extruder. The physical and chemical stability of materials during processing was determined using thermal gravimetric analysis and HPLC. The mechanism of drug release was determined using the Korsmeyer-Peppas model and the hydration and erosion of tablets during the dissolution studies were investigated. The excipient blends were physically and chemically stable during processing, and the resulting dosage forms exhibited pH-dependent dissolution properties. Extrusion of blends containing HPMC or carbomer changed the mechanism and kinetics of drug release from the thermally processed dosage forms. At concentrations of 5% or below, carbomer was more effective than HPMC at extending the duration of theophylline release from matrix tablets. Furthermore, carbomer containing tablets were stable upon storage for 3 months at 40 degrees C/75% RH. Thus, hot-melt extrusion was an effective process for the preparation of controlled release matrix systems based on Acryl-EZE.

  4. Superparamagnetic poly(methyl methacrylate) nanoparticles surface modified with folic acid presenting cell uptake mediated by endocytosis

    NASA Astrophysics Data System (ADS)

    Feuser, Paulo Emilio; Jacques, Amanda Virtuoso; Arévalo, Juan Marcelo Carpio; Rocha, Maria Eliane Merlin; dos Santos-Silva, Maria Claudia; Sayer, Claudia; de Araújo, Pedro H. Hermes

    2016-04-01

    The encapsulation of superparamagnetic nanoparticles (MNPs) in polymeric nanoparticles (NPs) with modified surfaces can improve targeted delivery and induce cell death by hyperthermia. The goals of this study were to synthesize and characterize surface modified superparamagnetic poly(methyl methacrylate) with folic acid (FA) prepared by miniemulsion polymerization (MNPsPMMA-FA) and to evaluate their in vitro cytotoxicity and cellular uptake in non-tumor cells, murine fibroblast (L929) cells and tumor cells that overexpressed folate receptor (FR) β, and chronic myeloid leukemia cells in blast crisis (K562). Lastly, hemolysis assays were performed on human red blood cells. MNPsPMMA-FA presented an average mean diameter of 135 nm and a saturation magnetization (Ms) value of 37 emu/g of iron oxide, as well as superparamagnetic behavior. The MNPsPMMA-FA did not present cytotoxicity in L929 and K562 cells. Cellular uptake assays showed a higher uptake of MNPsPMMA-FA than MNPsPMMA in K562 cells when incubated at 37 °C. On the other hand, MNPsPMMA-FA showed a low uptake when endocytosis mechanisms were blocked at low temperature (4 °C), suggesting that the MNPsPMMA-FA uptake was mediated by endocytosis. High concentrations of MNPsPMMA-FA showed hemocompatibility when incubated for 24 h in human red blood cells. Therefore, our results suggest that these carrier systems can be an excellent alternative in targeted drug delivery via FR.

  5. Molecular Imprinted Polymer of Methacrylic Acid Functionalised β-Cyclodextrin for Selective Removal of 2,4-Dichlorophenol

    PubMed Central

    Surikumaran, Hemavathy; Mohamad, Sharifah; Sarih, Norazilawati Muhamad

    2014-01-01

    This work describes methacrylic acid functionalized β-cyclodextrin (MAA-βCD) as a novel functional monomer in the preparation of molecular imprinted polymer (MIP MAA-βCD) for the selective removal of 2,4-dichlorophenol (2,4-DCP). The polymer was characterized using Fourier Transform Infrared (FTIR) spectroscopy, Brunauer-Emmett-Teller (BET) and Field Emission Scanning Electron Microscopy (FESEM) techniques. The influence of parameters such as solution pH, contact time, temperature and initial concentrations towards removal of 2,4-DCP using MIP MAA-βCD have been evaluated. The imprinted material shows fast kinetics and the optimum pH for removal of 2,4-DCP is pH 7. Compared with the corresponding non-imprinted polymer (NIP MAA-βCD), the MIP MAA-βCD exhibited higher adsorption capacity and outstanding selectivity towards 2,4-DCP. Freundlich isotherm best fitted the adsorption equilibrium data of MIP MAA-βCD and the kinetics followed a pseudo-second-order model. The calculated thermodynamic parameters showed that adsorption of 2,4-DCP was spontaneous and exothermic under the examined conditions. PMID:24727378

  6. Surface modification with poly(sulfobetaine methacrylate-co-acrylic acid) to reduce fibrinogen adsorption, platelet adhesion, and plasma coagulation.

    PubMed

    Kuo, Wei-Hsuan; Wang, Meng-Jiy; Chien, Hsiu-Wen; Wei, Ta-Chin; Lee, Chiapyng; Tsai, Wei-Bor

    2011-12-12

    Zwitterionic sulfobetaine methacrylate (SBMA) polymers were known to possess excellent antifouling properties due to high hydration capacity and neutral charge surface. In this study, copolymers of SBMA and acrylic acid (AA) with a variety of compositions were synthesized and were immobilized onto polymeric substrates with layer-by-layer polyelectrolyte films via electrostatic interaction. The amounts of platelet adhesion and fibrinogen adsorption were determined to evaluate hemocompatibility of poly(SBMA-co-AA)-modified substrates. Among various deposition conditions by modulating SBMA ratio in the copolymers and pH of the deposition solution, poly(SBMA(56)-co-AA(44)) deposited at pH 3.0 possessed the best hemocompatibility. This work demonstrated that poly(SBMA-co-AA) copolymers adsorbed on polyelectrolyte-base films via electrostatic interaction improve hemocompatibility effectively and are applicable for various substrates including TCPS, PU, and PDMS. Furthermore, poly(SBMA-co-AA)-coated substrate possesses great durability under rigorous conditions. The preliminary hemocompatibility tests regarding platelet adhesion, fibrinogen adsorption, and plasma coagulation suggest the potential of this technique for the application to blood-contacting biomedical devices.

  7. Experimental study of albumin and lysozyme adsorption onto acrylic acid (AA) and 2-hydroxyethyl methacrylate (HEMA) surfaces.

    PubMed

    Moradi, Omid; Modarress, Hamid; Noroozi, Mehdi

    2004-03-01

    Many commercial soft contact lenses are based on poly-2-hydroxyethyl methacrylate (HEMA) and acrylic acid (AA) hydrogels. The adsorption of proteins, albumin and lysozyme, on such contact lens surfaces may cause problems in their applications. In this work the adsorption of proteins, albumin and lysozyme, on hydrogel surfaces, AA and HEMA, was investigated as a function of concentration of protein. Also the effects of pH and ionic strength of protein solution on the adsorption of protein were examined. The obtained results indicated that the degree of adsorption of protein increased with the concentration of protein, and the adsorption of albumin on HEMA surface at the studied pHs (6.2-8.6) was higher than AA surface, whereas the adsorption of lysozyme on AA surface at the same pHs was higher than HEMA. The change in ionic strength of protein solution affected the proteins adsorption on both AA and HEMA surfaces. Also, the amount of sodium ions deposited on the AA surface was much higher than HEMA surface. This effect can be related to the negative surface charge of AA and its higher tendency for adsorption of sodium ions compared to the HEMA surface.

  8. Chitosan-functionalised poly(2-hydroxyethyl methacrylate) core-shell microgels as drug delivery carriers: salicylic acid loading and release.

    PubMed

    Mahattanadul, Natshisa; Sunintaboon, Panya; Sirithip, Piyawan; Tuchinda, Patoomratana

    2016-09-01

    This work presents the evaluation of chitosan-functionalised poly(2-hydroxyethyl methacrylate) (CS/PHEMA) core-shell microgels as drug delivery carriers. CS/PHEMA microgels were prepared by emulsifier-free emulsion polymerisation with N,N '-methylenebisacrylamide (MBA) as a crosslinker. The study on drug loading, using salicylic acid (SA) as a model drug, was performed. The results showed that the encapsulation efficiency (EE) increased as drug-to-microgel ratio was increased. Higher EE can be achieved with the increase in degree of crosslinking, by increasing the amount of MBA from 0.01 g to 0.03 g. In addition, the highest EE (61.1%) was observed at pH 3. The highest release of SA (60%) was noticed at pH 2.4, while the lowest one (49.4%) was obtained at pH 7.4. Moreover, the highest release of SA was enhanced by the presence of 0.2 M NaCl. The pH- and ionic-sensitivity of CS/PHEMA could be useful as a sustained release delivery device, especially for oral delivery.

  9. Deposition kinetics and characterization of stable ionomers from hexamethyldisiloxane and methacrylic acid by plasma enhanced chemical vapor deposition

    SciTech Connect

    Urstöger, Georg; Resel, Roland; Coclite, Anna Maria; Koller, Georg

    2016-04-07

    A novel ionomer of hexamethyldisiloxane and methacrylic acid was synthesized by plasma enhanced chemical vapor deposition (PECVD). The PECVD process, being solventless, allows mixing of monomers with very different solubilities, and for polymers formed at high deposition rates and with high structural stability (due to the high number of cross-links and covalent bonding to the substrate) to be obtained. A kinetic study over a large set of parameters was run with the aim of determining the optimal conditions for high stability and proton conductivity of the polymer layer. Copolymers with good stability over 6 months' time in air and water were obtained, as demonstrated by ellipsometry, X-Ray reflectivity, and FT-IR spectroscopy. Stable coatings showed also proton conductivity as high as 1.1 ± 0.1 mS cm{sup −1}. Chemical analysis showed that due to the high molecular weight of the chosen precursors, it was possible to keep the plasma energy-input-per-mass low. This allowed limited precursor fragmentation and the functional groups of both monomers to be retained during the plasma polymerization.

  10. Formation of quasi-regular compact structure of poly(methacrylic acid) upon an interaction with alpha-chymotrypsin.

    PubMed

    Kudryashova, E V; Gladilin, A K; Izumrudov, V A; van Hoek, A; Visser, A J; Levashov, A V

    2001-12-17

    Structure and dynamic properties of free poly(methacrylic acid) (PMA) and PMA complexed with alpha-chymotrypsin (CT) were studied using the time resolved fluorescence anisotropy technique. We have found that the interaction of PMA with CT induces the formation of a quasi-regular structure of PMA. At a CT/PMA weight ratio of 4:1 the interaction with CT leads to formation of approximately four equal segments of polyelectrolyte, each binding one CT molecule and characterized by an independent rotational mobility. Increase of the CT/PMA weight ratio above 8:1 gives rise to the overall rotation of the whole enzyme-polyelectrolyte complex. In water-ethanol mixtures the mobility of PMA segments containing CT decreases and the structure of the complex becomes even more rigid due to enhancement of the electrostatic interaction between CT and PMA. Formation of the compact and quasi-regular structure of the complex is perhaps the main reason behind the enhancement of enzyme stability and suppression of enzyme aggregation in water-organic cosolvent mixtures.

  11. Acrylic acid-methyl methacrylate (2.5:7.5/2:8) enteric copolymer for colon targeted drug delivery.

    PubMed

    Vijay, Saurabh; Sati, O P; Majumdar, Dipak K

    2011-01-01

    Enteric copolymers of acrylic acid and methyl methacrylate (2.5:7.5 and 2:8) were prepared using tetrahydrofuran as solvent and AIBN as free radical initiator for colon targeting. FTIR and (1)H NMR spectra of the copolymers showed absence of vinyl bond/protons present in the monomers suggesting successful polymerization. Flurbiprofen sodium microspheres (M1 and M2) made with the copolymers, by oil/oil solvent evaporation, were spherical, anionic (zeta potential -57.8 and -53.7 mV) and contained 5.47 and 5.89% drug. FTIR spectrum of microspheres showed peaks for aromatic C = C stretching and substituted benzene ring, indicating entrapment of flurbiprofen. PXRD revealed crystalline structure of flurbiprofen while copolymer and microspheres were amorphous. DSC thermograms showed a sharp melting endotherm of flurbiprofen sodium at 129.26°C against broad endotherms of copolymers and microspheres. The microspheres released 43 and 36% drug at pH 6.8 in 2 h and 99 and 96% at pH 7.4 in next 3-4 h.The microspheres did not adhere on gastric-mucosa at pH 1.2 but showed mucoadhesion time of 18 min and 9 min on intestinal mucosa at pH 6.8. Thus, the microspheres on oral administration, would release the drug in colon, suggesting the potential of the hemocompatible copolymers for pH dependent colon targeted drug delivery system.

  12. Corrosion resistance of siloxane-poly(methyl methacrylate) hybrid films modified with acetic acid on tin plate substrates: Influence of tetraethoxysilane addition

    NASA Astrophysics Data System (ADS)

    Kunst, S. R.; Cardoso, H. R. P.; Oliveira, C. T.; Santana, J. A.; Sarmento, V. H. V.; Muller, I. L.; Malfatti, C. F.

    2014-04-01

    The aim of this paper is to study the corrosion resistance of hybrid films. Tin plate was coated with a siloxane-poly (methyl methacrylate) (PMMA) hybrid film prepared by sol-gel route with covalent bonds between the organic (PMMA) and inorganic (siloxane) phases obtained by hydrolysis and polycondensation of 3-(trimethoxysilylpropyl) methacrylate (TMSM) and polymerization of methyl methacrylate (MMA) using benzoyl peroxide (BPO) as a thermic initiator. Hydrolysis reactions were catalyzed by acetic acid solution avoiding the use of chlorine or stronger acids in the film preparation. The effect of the addition of tetraethoxysilane (TEOS) on the protective properties of the film was evaluated. The hydrophobicity of the film was determined by contact angle measurements, and the morphology was evaluated by scanning electron microscopy (SEM) and profilometry. The local nanostructure was investigated by Fourier transform infrared spectroscopy (FT-IR). The electrochemical behavior of the films was assessed by open circuit potential monitoring, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) measurements in a 0.05 M NaCl solution. The mechanical behavior was evaluated by tribology. The results highlighted that the siloxane-PMMA hybrid films modified with acetic acid are promising anti-corrosive coatings that acts as an efficient diffusion barrier, protecting tin plates against corrosion. However, the coating properties were affected by the TEOS addition, which contributed for the thickness increase and irregular surface coverage.

  13. Molecularly Imprinted Solid Phase Extraction using Bismethacryloyl-β-cyclodextrin and Methacrylic Acid as Double Functional Monomers for Selective Analysis of Glycyrrhizic Acid in Aqueous Media.

    PubMed

    Tang, Weili; Du, Wei; Guo, Pengqi; Wu, Ningli; Du, Kangli; Xu, Changgen; Luo, Zhimin; Chang, Ruimiao; Zeng, Aiguo; Jing, Wanghui; Chang, Chun; Li, Ji; Fu, Qiang

    2017-02-01

    In this work, a new molecularly imprinted solid phase extraction protocol was developed for the selective extraction and purification of glycyrrhizic acid from liquorice roots in aqueous media. The molecularly imprinted polymers (MIPs) for glycyrrhizic acid were prepared by using bismethacryloyl-β-cyclodextrin and methacrylic acid as double functional monomers and characterized by Fourier transform infrared spectroscopy, scanning electron microscope, thermo gravimetric analysis, nitrogen adsorption and elemental analysis. In aqueous media, the adsorption properties of MIPs including adsorption kinetics, adsorption isotherms and selectivity adsorption were investigated. The characterization of imprinted polymers indicated that the prepared MIPs had good stability and many cavity structures. The results of adsorption experiments illustrated the MIPs had high adsorption capacity of glycyrrhizic acid (69.3 mg g(-1)) with the imprinting factor 3.77, and it took ~5 min to get adsorption equilibrium. The MIPs could be used as an solid phase extraction sorbent absorbent for enrichment and purification of glycyrrhizic acid from the crude extraction of licorice roots, and the results showed promising practical value. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  14. A 2,5-Dihydroxybenzoic Acid-Gelatin Conjugate: The Synthesis, Antiviral Activity and Mechanism of Antiviral Action Against Two Alphaherpesviruses.

    PubMed

    Lisov, Alexander; Vrublevskaya, Veronika; Lisova, Zoy; Leontievsky, Alexey; Morenkov, Oleg

    2015-10-15

    Various natural and synthetic polyanionic polymers with different chemical structures are known to exhibit potent antiviral activity in vitro toward a variety of enveloped viruses and may be considered as promising therapeutic agents. A water-soluble conjugate of 2,5-dihydroxybezoic acid (2,5-DHBA) with gelatin was synthesized by laccase-catalyzed oxidation of 2,5-DHBA in the presence of gelatin, and its antiviral activity against pseudorabies virus (PRV) and bovine herpesvirus type 1 (BoHV-1), two members of the Alphaherpesvirinae subfamily, was studied. The conjugate produced no direct cytotoxic effect on cells, and did not inhibit cell growth at concentrations up to 1000 µg/mL. It exhibited potent antiviral activity against PRV (IC50, 1.5-15 µg/mL for different virus strains) and BoHV-1 (IC50, 0.5-0.7 µg/mL). When present during virus adsorption, the conjugate strongly inhibited the attachment of PRV and BoHV-1 to cells. The 2,5-DHBA-gelatin conjugate had no direct virucidal effect on the viruses and did not influence their penetration into cells, cell-to-cell spread, production of infectious virus particles in cells, and expression of PRV glycoproteins E and B. The results indicated that the 2,5-DHBA-gelatin conjugate strongly inhibits the adsorption of alphaherpesviruses to cells and can be a promising synthetic polymer for the development of antiviral formulations against alphaherpesvirus infections.

  15. Impact of immobilizing of low molecular weight hyaluronic acid within gelatin-based hydrogel through enzymatic reaction on behavior of enclosed endothelial cells.

    PubMed

    Khanmohammadi, Mehdi; Sakai, Shinji; Taya, Masahito

    2017-04-01

    The hydrogels having the ability to promote migration and morphogenesis of endothelial cells (ECs) are useful for fabricating vascularized dense tissues in vitro. The present study explores the immobilization of low molecular weight hyaluronic acid (LMWHA) derivative within gelatin-based hydrogel to stimulate migration of ECs. The LMWHA derivative possessing phenolic hydroxyl moieties (LMWHA-Ph) was bound to gelatin-based derivative hydrogel through the horseradish peroxidase-catalyzed reaction. The motility of ECs was analyzed by scratch migration assay and microparticle-based cell migration assay. The incorporated LMWHA-Ph molecules within hydrogel was found to be preserved stably through covalent bonds during incubation. The free and immobilized LMWHA-Ph did not lose an inherent stimulatory effect on human umbilical vein endothelial cells (HUVECs). The immobilized LMWHA-Ph within gelatin-based hydrogel induced the high motility of HUVECs, accompanied by robust cytoskeleton extension, and cell subpopulation expressing CD44 cell receptor. In the presence of immobilized LMWHA-Ph, the migration distance and the number of existing HUVECs were demonstrated to be encouraged in dose-dependent and time-dependent manners. Based on the results obtained in this work, it was concluded that the enzymatic immobilization of LMWHA-Ph within gelatin-based hydrogel represents a promising approach to promote ECs' motility and further exploitation for vascular tissue engineering applications. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. Biomineralization of electrospun poly( L -lactic acid)/gelatin composite fibrous scaffold by using a supersaturated simulated body fluid with continuous CO 2 bubbling

    NASA Astrophysics Data System (ADS)

    Cai, Qing; Xu, Qingqing; Feng, Qiaofang; Cao, Xiaoyan; Yang, Xiaoping; Deng, Xuliang

    2011-09-01

    To promote the biomineralization, supersaturated simulated body fluids (SBFs), e.g. five times SBF (5 × SBF), were usually applied. In these SBFs, however, homogeneous nucleation of Ca-P mineralites and deposition unavoidably took place owing to the HCO3- decomposition and the pH value increment, which made the prediction of bone bioactivity of substrates controversial. In this study, the classically prepared 5 × SBF was continuously bubbled with CO2 to keep the pH value stable at 6.4 and the solution transparent, and a kind of electrospun poly(L-lactic acid)/gelatin composite fibers was used for the biomineralization study. In such a modified 5 × SBF, heterogenenous nucleation occurred dominantly and thermodynamical unstable brushites (dicalcium phosphate dihydrate, DCPD) were detected shortly on both electrospun PLLA fibers and PLLA/gelatin (1:1 in weight) composite fibers. In comparison with electrospun PLLA fibers, the sheet-like DCPD mineralites transformed into flaky carbonated calcium-deficient hydroxyapatite (CDHA) within 24 h on the PLLA/gelatin composite fibers due to the accelerating effect of gelatin component. The formed apatite coating contained much less Mg2+ ions than that deposited in the classical 5 × SBF. The results of this study showed that supersaturated SBFs buffered with gassy CO2 were expected good choices for the accelerated biomineralization, and for the prediction of the bone bonding bioactivity of substrates.

  17. Poly(hydroxyethyl methacrylate-co-methacryloylglutamic acid) nanospheres for adsorption of Cd2+ ions from aqueous solutions

    NASA Astrophysics Data System (ADS)

    Esen, Cem; Şenay, Raziye Hilal; Feyzioğlu, Esra; Akgöl, Sinan

    2014-02-01

    Poly(2-hydroxyethyl methacrylate-co- N-methacryloyl-( l)-glutamic acid) p(HEMA-MAGA) nanospheres have been synthesized, characterized, and used for the adsorption of Cd2+ ions from aqueous solutions. Nanospheres were prepared by surfactant free emulsion polymerization. The p(HEMA-MAGA) nanospheres were characterized by SEM, FTIR, zeta size, and elemental analysis. The specific surface area of nanospheres was found to be 1,779 m2/g. According to zeta size analysis results, average size of nanospheres is 147.3 nm with poly-dispersity index of 0.200. The goal of this study was to evaluate the adsorption performance of p(HEMA-MAGA) nanospheres for Cd2+ ions from aqueous solutions by a series of batch experiments. The Cd2+ concentration was determined by inductively coupled plasma-optical emission spectrometer. Equilibrium sorption experiments indicated a Cd2+ uptake capacity of 44.2 mg g-1 at pH 4.0 at 25 °C. The adsorption of Cd2+ ions increased with increasing pH and reached a plateau value at around pH 4.0. The data were successfully modeled with a Langmuir equation. A series of kinetics experiments was then carried out and a pseudo-second order equation was used to fit the experimental data. Desorption experiments which were carried out with nitric acid showed that the p(HEMA-MAGA) nanospheres could be reused without significant losses of their initial properties in consecutive adsorption and elution operations.

  18. Tandem mass spectrometry of poly(methacrylic Acid) oligomers produced by negative mode electrospray ionization.

    PubMed

    Giordanengo, Rémi; Viel, Stéphane; Allard-Breton, Béatrice; Thévand, André; Charles, Laurence

    2009-01-01

    Dissociation of small poly(methyl acrylic acid) (PMAA) anions produced by electrospray was characterized by tandem mass spectrometry. Upon collisional activation, singly, and doubly deprotonated PMAA oligomers were shown to fragment via two major reactions, dehydration and decarboxylation. The elimination of a water molecule would occur between two consecutive acid groups in a charged-remote mechanism, giving rise to cyclic anhydrides, and was shown to proceed as many times as pairs of neutral pendant groups were available. As a result, the number of dehydration steps, together with the abundance of the fragment ions produced after the release of all water molecules, revealed the polymerization degree of the molecule in the particular case of doubly charged oligomers. For singly deprotonated molecules, the exact number of MAA units could be reached from the number of carbon dioxide molecules successively eliminated from the fully dehydrated precursor ions. In contrast to dehydration, decarboxylation reactions would proceed via a charge-induced mechanism. The proposed dissociation mechanisms are consistent with results commonly reported in thermal degradation studies of poly(acrylic acid) resins and were supported by accurate mass measurements. These fragmentation rules were successfully applied to characterize a polymeric impurity detected in the tested PMAA sample.

  19. Different effects of fluid loading with saline, gelatine, hydroxyethyl starch or albumin solutions on acid-base status in the critically ill.

    PubMed

    Spoelstra-de Man, Angélique M E; Smorenberg, Annemieke; Groeneveld, A B Johan

    2017-01-01

    Fluid administration in critically ill patients may affect acid-base balance. However, the effect of the fluid type used for resuscitation on acid-base balance remains controversial. We studied the effect of fluid resuscitation of normal saline and the colloids gelatine 4%, hydroxyethyl starch (HES) 6%, and albumin 5% on acid-base balance in 115 clinically hypovolemic critically ill patients during a 90 minute filling pressure-guided fluid challenge by a post-hoc analysis of a prospective randomized clinical trial. About 1700 mL was infused per patient in the saline and 1500 mL in each of the colloid groups (P<0.001). Overall, fluid loading slightly decreased pH (P<0.001) and there was no intergroup difference. This mildly metabolic acidifying effect was caused by a small increase in chloride concentration and decrease in strong ion difference in the saline- and HES-, and an increase in (uncorrected) anion gap in gelatine- and albumin-loaded patients, independent of lactate concentrations. In clinically hypovolemic, critically ill patients, fluid resuscitation by only 1500-1700 mL of normal saline, gelatine, HES or albumin, resulted in a small decrease in pH, irrespective of the type of fluid used. Therefore, a progressive metabolic acidosis, even with increased anion gap, should not be erroneously attributed to insufficient fluid resuscitation. ISRCTN Registry ISRCTN19023197.

  20. Hybrid polymeric hydrogels for ocular drug delivery: nanoparticulate systems from copolymers of acrylic acid-functionalized chitosan and N-isopropylacrylamide or 2-hydroxyethyl methacrylate.

    PubMed

    Barbu, Eugen; Verestiuc, Liliana; Iancu, Mihaela; Jatariu, Anca; Lungu, Adriana; Tsibouklis, John

    2009-06-03

    Nanoparticulate hybrid polymeric hydrogels (10-70 nm) have been obtained via the radical-induced co-polymerization of acrylic acid-functionalized chitosan with either N-isopropylacrylamide or 2-hydroxyethyl methacrylate, and the materials have been investigated for their ability to act as controlled release vehicles in ophthalmic drug delivery. Studies on the effects of network structure upon swelling properties, adhesiveness to substrates that mimic mucosal surfaces and biodegradability, coupled with in vitro drug release investigations employing ophthalmic drugs with differing aqueous solubilities, have identified nanoparticle compositions for each of the candidate drug molecules. The hybrid nanoparticles combine the temperature sensitivity of N-isopropylacrylamide or the good swelling characteristics of 2-hydroxyethyl methacrylate with the susceptibility of chitosan to lysozyme-induced biodegradation.

  1. Hybrid polymeric hydrogels for ocular drug delivery: nanoparticulate systems from copolymers of acrylic acid-functionalized chitosan and N-isopropylacrylamide or 2-hydroxyethyl methacrylate

    NASA Astrophysics Data System (ADS)

    Barbu, Eugen; Verestiuc, Liliana; Iancu, Mihaela; Jatariu, Anca; Lungu, Adriana; Tsibouklis, John

    2009-06-01

    Nanoparticulate hybrid polymeric hydrogels (10-70 nm) have been obtained via the radical-induced co-polymerization of acrylic acid-functionalized chitosan with either N-isopropylacrylamide or 2-hydroxyethyl methacrylate, and the materials have been investigated for their ability to act as controlled release vehicles in ophthalmic drug delivery. Studies on the effects of network structure upon swelling properties, adhesiveness to substrates that mimic mucosal surfaces and biodegradability, coupled with in vitro drug release investigations employing ophthalmic drugs with differing aqueous solubilities, have identified nanoparticle compositions for each of the candidate drug molecules. The hybrid nanoparticles combine the temperature sensitivity of N-isopropylacrylamide or the good swelling characteristics of 2-hydroxyethyl methacrylate with the susceptibility of chitosan to lysozyme-induced biodegradation.

  2. Laser sintered porous polycaprolacone scaffolds loaded with hyaluronic acid and gelatin-grafted thermoresponsive hydrogel for cartilage tissue engineering.

    PubMed

    Lee, Ming-Yih; Tsai, Wen-Wei; Chen, His-Jung; Chen, Jyh-Ping; Chen, Chih-Hao; Yeh, Wen-Lin; An, Jia

    2013-01-01

    The aim of this study is to evaluate a soft/hard bi-phase scaffold for cartilage tissue engineering. Chondrocyte proliferation, glycoaminoglycan production and total collagen content are compared between laser-sintered porous polycaprolactone (PCL) scaffolds with and without a thermoresponsive hydrogel grafted with hyaluronic acid and gelatin. The in vitro results show that scaffolds loaded with hydrogel have a higher initial chondrocyte attachment than PCL scaffolds. At day 21 and 28, scaffolds loaded with hydrogel have a significantly higher glycosaminoglycan (GAG) production than PCL scaffolds alone, and total collagen content including collagen type II in the hydrogel-loaded group is three times higher than the group without hydrogel. It is concluded that the laser-sintered porous PCL scaffold has good cytocompatibility, and that the hydrogel phase is able to enhance initial chondrocytes attachment as well as GAG and collagen production of chondrocytes. This study suggests that a soft/hard bi-phase scaffold may be used for cartilage tissue engineering to enhance in vitro chondrogenesis.

  3. Graphene oxide/poly(acrylic acid)/gelatin nanocomposite hydrogel: experimental and numerical validation of hyperelastic model.

    PubMed

    Faghihi, Shahab; Karimi, Alireza; Jamadi, Mahsa; Imani, Rana; Salarian, Reza

    2014-05-01

    Owing to excellent thermal and mechanical properties, graphene-based nanomaterials have recently attracted intensive attention for a wide range of applications, including biosensors, bioseparation, drug release vehicle, and tissue engineering. In this study, the effects of graphene oxide nanosheet (GONS) content on the linear (tensile strength and strain) and nonlinear (hyperelastic coefficients) mechanical properties of poly(acrylic acid) (PAA)/gelatin (Gel) hydrogels are evaluated. The GONS with different content (0.1, 0.3, and 0.5 wt.%) is added into the prepared PAA/Gel hydrogels and composite hydrogels are subjected to a series of tensile and stress relaxation tests. Hyperelastic strain energy density functions (SEDFs) are calibrated using uniaxial experimental data. The potential ability of different hyperelastic constitutive equations (Neo-Hookean, Yeoh, and Mooney-Rivlin) to define the nonlinear mechanical behavior of hydrogels is verified by finite element (FE) simulations. The results show that the tensile strength (71%) and elongation at break (26%) of composite hydrogels are significantly increased by the addition of GONS (0.3 wt.%). The experimental data is well fitted with those predicted by the FE models. The Yeoh material model accurately defines the nonlinear behavior of hydrogels which can be used for further biomechanical simulations of hydrogels. This finding might have implications not only for the improvement of the mechanical properties of composite hydrogels but also for the fabrication of polymeric substrate materials suitable for tissue engineering applications.

  4. Hybrid molecularly imprinted poly(methacrylic acid-TRIM)-silica chemically modified with (3-glycidyloxypropyl)trimethoxysilane for the extraction of folic acid in aqueous medium.

    PubMed

    de Oliveira, Fernanda Midori; Segatelli, Mariana Gava; Tarley, César Ricardo Teixeira

    2016-02-01

    In the present study a hybrid molecularly imprinted poly(methacrylic acid-trimethylolpropane trimethacrylate)-silica (MIP) was synthesized and modified with (3-glycidyloxypropyl)trimethoxysilane (GPTMS) with posterior opening of epoxy ring to provide hydrophilic properties of material in the extraction of folic acid from aqueous medium. The chemical and structural aggregates of hybrid material were characterized by means of Fourier Transform Infrared (FT-IR), Transmission Electron Microscopy (TEM), Scanning Electron Microscopy (SEM), Thermogravimetric analysis (TGA) and textural data. Selectivity data of MIP were compared to non-imprinted polymer (NIP) through competitive sorption studies in the presence of caffeine, paracetamol or 4-aminobenzamide yielding relative selectivity coefficients (k′) higher than one unit, thus confirming the selective character of MIP even in the presence of structurally smaller compounds than the folic acid. The lower hydrophobic sorption by bovine serum albumin (BSA) in the MIP as compared to unmodified MIP proves the hydrophilicity of polymer surface by using GPTMS with opening ring. Under acid medium(pH 1.5) the sorption of folic acid onto MIP from batch experiments was higher than the one achieved for NIP. Equilibrium sorption of folic acid was reached at 120 min for MIP, NIP and MIP without GPTMS and kinetic sorption data were well described by pseudo-second-order, Elovich and intraparticle diffusion models. Thus, these results indicate the existence of different binding energy sites in the polymers and a complex mechanism consisting of both surface sorption and intraparticle transport of folic acid within the pores of polymers.

  5. Buffer capacity of 4% succinylated gelatin does not provide any advantages over acidic 6% hydroxyethyl starch 130/0.4 for acid-base balance during experimental mixed acidaemia in a porcine model.

    PubMed

    Esche, V; Russ, M; Melzer, S; Grossmann, B; Boemke, W; Unger, J K

    2008-11-01

    Four percent gelatine is an alkaline compound due to NH2 groups, whereas 6% hydroxyethyl starch 130/0.4 (HES130) has acidic features. We investigated whether these solutions lead to differences in acid-base balance in pigs during acidaemia and correction of pH. Anaesthetized pigs were randomized to HES130 or gelatine infusion (n = 5 per group). Animals received acid infusion (0.4 M solution of lactic acid and HCl diluted in normal saline) and low tidal volume ventilation (6-7 mL kg(-1), PaCO2 of 80-85 mmHg, pH 7.19-7.24). Measurements were made before and after induction of acidaemia, before and after correction of pH with haemofiltration (continuous venovenous haemofiltration) and tris-hydroxymethylaminomethane infusion. We measured parameters describing acid-base balance according to Stewart's approach, ketone body formation, oxygen delivery, haemodynamics, diuresis and urinary pH. Acid-base balance did not differ significantly between the groups. In HES130-treated pigs, the haemodilution-based drop of haemoglobin (1.4 +/- 1.0 g dL(-1), median +/- SD) was paralleled by an increase in the cardiac output (0.5 +/- 0.4 L min(-1). Lacking increases in cardiac output, gelatine-treated pigs demonstrated a reduction in oxygen delivery (149.4 +/- 106.0 mL min(-1)). Tris-hydroxymethylaminomethane volumes required for pH titration to desired values were significantly higher in the gelatine group (0.7 +/- 0.1 mL kg(-1) h(-1) vs. HES130: 0.5 +/- 0.2 mL kg(-1) h(-1)). The buffer capacity of gelatine did not lead to favourable differences in acid-base balance in comparison to HES130.

  6. Plasma-induced graft copolymerization of poly(methacrylic acid) on electrospun poly(vinylidene fluoride) nanofiber membrane.

    PubMed

    Kaur, Satinderpal; Ma, Zuwei; Gopal, Renuga; Singh, Gurdev; Ramakrishna, Seeram; Matsuura, Takeshi

    2007-12-18

    Electrospun nanofibrous membranes (ENM) which have a porous structure have a huge potential for various liquid filtration applications. In this paper, we explore the viability of using plasma-induced graft copolymerization to reduce the pore sizes of ENMs. Poly(vinylidene) fluoride (PVDF) was electrospun to produce a nonwoven membrane, comprised of nanofibers with diameters in the range of 200-600 nm. The surface of the ENM was exposed to argon plasma and subsequently graft-copolymerized with methacrylic acid. The effect of plasma exposure time on grafting was studied for both the ENM and a commercial hydrophobic PVDF (HVHP) membrane. The grafting density was quantitatively measured with toluidine blue-O. The degree of grafting increased steeply with an increase in plasma exposure time for the ENM, attaining a maximum of 180 nmol/mg after 120 s of plasma treatment. However, the increase in the grafting density on the surface of the HVHP membrane was not as drastic, reaching a plateau of 65 nmol/mg after 60 s. The liquid entry permeation of water dropped extensively for both membranes, indicating a change in surface properties. Field emission scanning electron microscopy micrographs revealed an alteration in the surface pore structure for both membranes after grafting. Bubble point measurements of the ENM reduced from 3.6 to 0.9 um after grafting. The pore-size distribution obtained using the capillary flow porometer for the grafted ENM revealed that it had a similar profile to that of a commercial hydrophilic commercial PVDF (HVLP) membrane. More significantly, water filtration studies revealed that the grafted ENM had a better flux throughput than the HVLP membrane. This suggests that ENMs can be successfully engineered through surface modification to achieve smaller pores while retaining their high flux performance.

  7. Increased cellular uptake of lauryl gallate loaded in superparamagnetic poly(methyl methacrylate) nanoparticles due to surface modification with folic acid.

    PubMed

    Feuser, Paulo Emilio; Arévalo, Juan Marcelo Carpio; Junior, Enio Lima; Rossi, Gustavo Rodrigues; da Silva Trindade, Edvaldo; Rocha, Maria Eliane Merlin; Jacques, Amanda Virtuoso; Ricci-Júnior, Eduardo; Santos-Silva, Maria Claudia; Sayer, Claudia; de Araújo, Pedro H Hermes

    2016-12-01

    Lauryl gallate loaded in superparamagnetic poly(methyl methacrylate) nanoparticles surface modified with folic acid were synthesized by miniemulsion polymerization in just one step. In vitro biocompatibility and cytotoxicity assays on L929 (murine fibroblast), human red blood, and HeLa (uterine colon cancer) cells were performed. The effect of folic acid at the nanoparticles surface was evaluated through cellular uptake assays in HeLa cells. Results showed that the presence of folic acid did not affect substantially the polymer particle size (~120 nm), the superparamagnetic behavior, the encapsulation efficiency of lauryl gallate (~87 %), the Zeta potential (~38 mV) of the polymeric nanoparticles or the release profile of lauryl gallate. The release profile of lauryl gallate from superparamagnetic poly(methyl methacrylate) nanoparticles presented an initial burst effect (0-1 h) followed by a slow and sustained release, indicating a biphasic release system. Lauryl gallate loaded in superparamagnetic poly(methyl methacrylate) nanoparticles with folic acid did not present cytotoxicity effects on L929 and human red blood cells. However, free lauryl gallate presented significant cytotoxic effects on L929 and human red blood cells at all tested concentrations. The presence of folic acid increased the cytotoxicity of lauryl gallate loaded in nanoparticles on HeLa cells due to a higher cellular uptake when HeLa cells were incubated at 37 °C. On the other hand, when the nanoparticles were incubated at low temperature (4 °C) cellular uptake was not observed, suggesting that the uptake occurred by folate receptor mediated energy-dependent endocytosis. Based on presented results our work suggests that this carrier system can be an excellent alternative in targeted drug delivery by folate receptor.

  8. Laser damage threshold of gelatin and a copper phthalocyanine doped gelatin optical limiter

    SciTech Connect

    Brant, M.C.; McLean, D.G.; Sutherland, R.L.

    1996-12-31

    The authors demonstrate optical limiting in a unique guest-host system which uses neither the typical liquid or solid host. Instead, they dope a gelatin gel host with a water soluble Copper (II) phthalocyaninetetrasulfonic acid, tetrasodium salt (CuPcTs). They report on the gelatin`s viscoelasticity, laser damage threshold, and self healing of this damage. The viscoelastic gelatin has mechanical properties quite different than a liquid or solid. The authors` laser measurements demonstrate that the single shot damage threshold of the undoped gelatin host increases with decreasing gelatin concentration. The gelatin also has a much higher laser damage threshold than a stiff acrylic. Unlike brittle solids, the soft gelatin self heals from laser induced damage. Optical limiting test also show the utility of a gelatin host doped with CuPcTs. The CuPcTs/gelatin matrix is not damaged at incident laser energies 5 times the single shot damage threshold of the gelatin host. However, at this high laser energy the CuPcTs is photo bleached at the beam waist. The authors repair photo bleached sites by annealing the CuPcTs/gelatin matrix.

  9. Fabrication and characterization of superparamagnetic and thermoresponsive hydrogels based on oleic-acid-coated Fe 3O 4 nanoparticles, hexa(ethylene glycol) methyl ether methacrylate and 2-(acetoacetoxy)ethyl methacrylate

    NASA Astrophysics Data System (ADS)

    Papaphilippou, Petri C.; Pourgouris, Antonis; Marinica, Oana; Taculescu, Alina; Athanasopoulos, George I.; Vekas, Ladislau; Krasia-Christoforou, Theodora

    2011-03-01

    Stimuli-responsive hydrogel nanocomposites comprised of swollen polymer networks, in which magnetic nanoparticles are embedded, are a relatively new class of "smart" soft materials presenting a significant impact on various technological and biomedical applications. A novel approach for the fabrication of hydrogel nanocomposites exhibiting temperature- and magneto-responsive behavior involves the random copolymerization of hexa(ethylene glycol) methyl ether methacrylate (HEGMA, hydrophilic, thermoresponsive) and 2-(acetoacetoxy)ethyl methacrylate (AEMA, hydrophobic, metal-chelating) in the presence of preformed oleic-acid-coated magnetite nanoparticles (OA·Fe 3O 4). In total, two series of hydrogel nanocomposites have been prepared in two different solvent systems: ethyl acetate (series A) and tetrahydrofuran (series B). The degrees of swelling (DSs) of all conetworks were determined in organic and in aqueous media. The nanocrystalline phase adopted by the embedded magnetic nanoparticles was investigated by X-ray diffraction (XRD) spectroscopy. The obtained diffraction patterns indicated the presence of magnetite (Fe 3O 4). Deswelling kinetic studies that were carried out at ˜60 °C in water demonstrated the thermoresponsive properties of the hydrogel nanocomposites, attributed to the presence of the hexaethylene glycol side chains within the conetworks. Moreover, thermal gravimetric analysis (TGA) measurements showed that these materials exhibited superior thermal stability compared to the pristine hydrogels. Further to the characterization of compositional and thermal properties, the assessment of magnetic characteristics by vibrational sample magnetometry (VSM) disclosed superparamagnetic behavior. The tunable superparamagnetic behavior exhibited by these materials depending on the amount of magnetic nanoparticles incorporated within the networks combined with their thermoresponsive properties may allow for their future exploitation in the biomedical field.

  10. Molecular Dynamics Simulations of Adsorption of Poly(acrylic acid) and Poly(methacrylic acid) on Dodecyltrimethylammonium Chloride Micelle in Water: Effect of Charge Density.

    PubMed

    Sulatha, Muralidharan S; Natarajan, Upendra

    2015-09-24

    We have investigated the interaction of dodecyltrimethylammonium chloride (DoTA) micelle with weak polyelectrolytes, poly(acrylic acid) and poly(methacrylic acid). Anionic as well as un-ionized forms of the polyelectrolytes were studied. Polyelectrolyte-surfactant complexes were formed within 5-11 ns of the simulation time and were found to be stable. Association is driven purely by electrostatic interactions for anionic chains whereas dispersion interactions also play a dominant role in the case of un-ionized chains. Surfactant headgroup nitrogen atoms are in close contact with the carboxylic oxygens of the polyelectrolyte chain at a distance of 0.35 nm. In the complexes, the polyelectrolyte chains are adsorbed on to the hydrophilic micellar surface and do not penetrate into the hydrophobic core of the micelle. Polyacrylate chain shows higher affinity for complex formation with DoTA as compared to polymethacrylate chain. Anionic polyelectrolyte chains show higher interaction strength as compared to corresponding un-ionized chains. Anionic chains act as polymeric counterion in the complexes, resulting in the displacement of counterions (Na(+) and Cl(-)) into the bulk solution. Anionic chains show distinct shrinkage upon adsorption onto the micelle. Detailed information about the microscopic structure and binding characteristics of these complexes is in agreement with available experimental literature.

  11. Poly(Lactic Acid) Hemodialysis Membranes with Poly(Lactic Acid)-block-Poly(2-Hydroxyethyl Methacrylate) Copolymer As Additive: Preparation, Characterization, and Performance.

    PubMed

    Zhu, Lijing; Liu, Fu; Yu, Xuemin; Xue, Lixin

    2015-08-19

    Poly(lactic acid) (PLA) hemodialysis membranes with enhanced antifouling capability and hemocompatibility were developed using poly(lactic acid)-block-poly(2-hydroxyethyl methacrylate) (PLA-PHEMA) copolymers as the blending additive. PLA-PHEMA block copolymers were synthesized via reversible addition-fragmentation (RAFT) polymerization from aminolyzed PLA. Gel permeation chromatography (GPC) and (1)H-nuclear magnetic resonance ((1)H NMR) were applied to characterize the synthesized products. By blending PLA with the amphiphilic block copolymer, PLA/PLA-PHEMA membranes were prepared by nonsolvent induced phase separation (NIPS) method. Their chemistry and structure were characterized with X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM) and atomic force microscopy (AFM). The results revealed that PLA/PLA-PHEMA membranes with high PLA-PHEMA contents exhibited enhanced hydrophilicity, water permeability, antifouling and hemocompatibility. Especially, when the PLA-PHEMA concentration was 15 wt %, the water flux of the modified membrane was about 236 L m(-2) h(-1). Its urea and creatinine clearance was more than 0.70 mL/min, lysozyme clearance was about 0.50 mL/min, BSA clearance was as less as 0.31 mL/min. All the results suggest that PLA-PHEMA copolymers had served as effective agents for optimizing the property of PLA-based membrane for hemodialysis applications.

  12. One-pot synthesis of biocompatible boronic acid-functionalized poly(methyl methacrylate) nanoparticles at sub-100 nm scale for glucose sensing

    NASA Astrophysics Data System (ADS)

    Sakalak, Huseyin; Ulasan, Mehmet; Yavuz, Emine; Camli, Sevket Tolga; Yavuz, Mustafa Selman

    2014-12-01

    Poly(methyl methacrylate) nanoparticles containing 4-vinylphenyl boronic acid were synthesized in one pot by surfactant-free emulsion polymerization. The nanoparticles were characterized by scanning electron microscopy and dynamic light scattering. Boron content in the nanoparticles was confirmed by electron-dispersive X-ray spectroscopy. In polymerization process, several co-monomer ratios were studied in order to obtain optimum nanoparticle size. Average hydrodynamic diameter and polydispersity index of nanoparticles versus variation of acetone percentage in the solvent mixture and total monomer concentration were investigated. The effect of boronic acid concentration in the monomer mixture on nanoparticle size and size distribution was also reported. Without further functionalization to the nanoparticles, the catechol dye, alizarin red S, was bound to boronic acid-containing nanoparticles. These nanoparticles behave as a nanosensor by which glucose or fructose can be easily detected. Dye-containing nanoparticles were undertaken displacement reaction by glucose or fructose. The glucose or fructose content was also monitored by UV-Visible spectrophotometer. Furthermore, cytotoxicity studies of boronic acid-carrying poly(methyl methacrylate) nanoparticles were carried out in 3T3 cells, which showed no toxicity effect on the cells.

  13. Atmospheric aqueous phase radical chemistry of the isoprene oxidation products methacrolein, methyl vinyl ketone, methacrylic acid and acrylic acid--kinetics and product studies.

    PubMed

    Schöne, Luisa; Schindelka, Janine; Szeremeta, Edyta; Schaefer, Thomas; Hoffmann, Dirk; Rudzinski, Krzysztof J; Szmigielski, Rafal; Herrmann, Hartmut

    2014-04-07

    Kinetic and mechanistic studies were conducted on the isoprene oxidation products methacrolein, methyl vinyl ketone, methacrylic and acrylic acid reacting with hydroxyl and nitrate radicals and sulfate radical anions in aqueous solution by use of the laser flash photolysis technique and a reversed-rate method for kinetics. High-performance liquid chromatography/mass spectrometry was applied for product analysis. The kinetic investigations show the highest reactivity of the hydroxyl radical followed by sulfate and nitrate radicals. For methacrolein and methyl vinyl ketone the following rate constants have been determined at 298 K: k(OH+methacrolein) = (9.4 ± 0.7) × 10(9) M(-1) s(-1), k(OH+methyl vinyl ketone) = (7.3 ± 0.5) × 10(9) M(-1) s(-1), k(NO3+methacrolein) = (4.0 ± 1.0) × 10(7) M(-1) s(-1), k(NO3+methyl vinyl ketone) = (9.7 ± 3.4) × 10(6) M(-1) s(-1), k(SO4(-)+methacrolein) = (9.9 ± 4.9) × 10(7) M(-1) s(-1) and k(SO4(-)+methyl vinyl ketone) = (1.0 ± 0.2) × 10(8) M(-1) s(-1). Temperature and pH dependencies of the reactions of OH, NO3 and SO4(-) with methacrolein, methyl vinyl ketone, methacrylic and acrylic acid as well as Arrhenius parameters have been obtained and discussed. Product studies were performed on the OH radical induced oxidation of methacrolein and methyl vinyl ketone. In the reaction of methacrolein + OH methylglyoxal and hydroxyacetone were identified as first oxidation products with yields of 0.099 and 0.162. Methylglyoxal was primarily produced in the oxidation of methyl vinyl ketone with a yield of 0.052. For both precursor compounds the formation of glycolaldehyde was observed for the first time with yields of 0.051 and 0.111 in the oxidation of methacrolein and methyl vinyl ketone, respectively. Furthermore, highly functionalised C4 compounds were determined from the oxidation of both precursor compounds, but for the first time for methyl vinyl ketone. Reaction schemes were developed based on known peroxyl radical

  14. Thermosensitive chitosan-gelatin-glycerol phosphate hydrogel as a controlled release system of ferulic acid for nucleus pulposus regeneration.

    PubMed

    Cheng, Yung-Hsin; Yang, Shu-Hua; Lin, Feng-Huei

    2011-10-01

    In the degenerative disc, overproduction of reactive oxygen species (ROS) involves in apoptosis and senescence of nucleus pulposus (NP) cells that could accelerate the degenerative process. Ferulic acid (FA) has been reported to have an excellent antioxidant property. In the study, injectable thermosensitive chitosan/gelatin/glycerol phosphate (C/G/GP) hydrogel was applied as a controlled release system for FA delivery. The study was aimed to evaluate possible therapeutic effects of FA-incorporated C/G/GP hydrogel on hydrogen peroxide (H(2)O(2))-induced oxidative stress NP cells. The results showed that the release of FA from C/G/GP hydrogel could decrease the H(2)O(2)-induced oxidative stress. Post-treatment of FA-incorporated C/G/GP hydrogel on H(2)O(2)-induced oxidative stress NP cells showed up-regulation of Aggrecan and type II collagen and down-regulation of MMP-3 in mRNA level. The results of sulfated-glycosaminoglycans (GAGs) to DNA ratio and alcian blue staining revealed that the GAGs production of H(2)O(2)-induced oxidative stress NP cells could reach to normal level. The results of caspase-3 activity and TUNEL staining indicated that FA-incorporated C/G/GP hydrogel decreased the apoptosis of H(2)O(2)-induced oxidative stress NP cells. The results suggested that the C/G/GP hydrogel was very suitable for sustained delivery of FA. The FA-incorporated C/G/GP hydrogel would be used to treat the degenerative disc in the early stage before it developed into the latter irreversible stages.

  15. [Gelatinous transformation of the bone marrow].

    PubMed

    Kemona, A; Dziecioł, J; Sulik, M; Brykalska, A; Sobaniec-Lotowska, M; Baltaziak, M

    1990-01-01

    The incidence and histopathologic picture of gelatinous transformation of the bone marrow were analysed in non-selected autopsy material. It was found that gelatinous transformation of the bone marrow occurred in terminal stages of various diseases (malignant neoplasms, chronic inflammation). Histological studies showed that gelatinous transformation of the bone marrow led to atrophy of the hematopoietic and adipose tissues of the bone marrow and accumulation of acid mucopolysaccharides. The patients with gelatinous transformation of the bone marrow exhibit hematologic disorders, most frequently anemia and thrombocytopenia.

  16. Synthesis of interpenetrating network hydrogel from poly(acrylic acid-co-hydroxyethyl methacrylate) and sodium alginate: modeling and kinetics study for removal of synthetic dyes from water.

    PubMed

    Mandal, Bidyadhar; Ray, Samit Kumar

    2013-10-15

    Several interpenetrating network (IPN) hydrogels were made by free radical in situ crosslink copolymerization of acrylic acid (AA) and hydroxy ethyl methacrylate in aqueous solution of sodium alginate. N,N'-methylenebisacrylamide (MBA) was used as comonomer crosslinker for making these crosslink hydrogels. All of these hydrogels were characterized by carboxylic content, FTIR, SEM, XRD, DTA-TGA and mechanical properties. Swelling, diffusion and network parameters of the hydrogels were studied. These hydrogels were used for adsorption of two important synthetic dyes, i.e. Congo red and methyl violet from water. Isotherms, kinetics and thermodynamics of dye adsorption by these hydrogels were also studied.

  17. Investigation of the self-healing mechanism of poly (ethylene co-methacrylic acid) copolymers utilizing ultrasonic time dependent resonant spectroscopy

    NASA Astrophysics Data System (ADS)

    Bowers, Nicholas R.; Pestka, Kenneth A., II; Kalista, Stephen J., Jr.

    2014-03-01

    The ultrasonic resonant spectra of four different poly (ethylene-co-methacrylic acid) copolymers (EMAA copolymers) have been obtained using the Time Dependent Resonant Spectroscopy (TDRS) method. The spectra of these EMAA copolymers, developed by DuPont (commercially known as: Nucrel 925, Nucrel 960, Surlyn 8920, and Surlyn 8940), were analyzed. Evolution of resonances and the associated energy dissipation within the samples were observed over a period of 10 ~ 50 hours. Results quantifying the influence of chemical properties (including molecular weight and ionic content), age, and damage mechanism on the self-healing response will be presented.

  18. Polymethyl methacrylate-co-methacrylic acid coatings with controllable concentration of surface carboxyl groups: A novel approach in fabrication of polymeric platforms for potential bio-diagnostic devices

    NASA Astrophysics Data System (ADS)

    Hosseini, Samira; Ibrahim, Fatimah; Djordjevic, Ivan; Koole, Leo H.

    2014-05-01

    The generally accepted strategy in development of bio-diagnostic devices is to immobilize proteins on polymeric surfaces as a part of detection process for diseases and viruses through antibody/antigen coupling. In that perspective, polymer surface properties such as concentration of functional groups must be closely controlled in order to preserve the protein activity. In order to improve the surface characteristics of transparent polymethacrylate plastics that are used for diagnostic devices, we have developed an effective fabrication procedure of polymethylmetacrylate-co-metacrylic acid (PMMA-co-MAA) coatings with controlled number of surface carboxyl groups. The polymers were processed effectively with the spin-coating technique and the detailed control over surface properties is here by demonstrated through the variation of a single synthesis reaction parameter. The chemical structure of synthesized and processed co-polymers has been investigated with nuclear magnetic resonance spectroscopy (NMR) and matrix-assisted laser desorption time-of-flight mass spectrometry (MALDI-ToF-MS). The surface morphology of polymer coatings have been analyzed with atomic force microscopy (AFM) and scanning electron microscopy (SEM). We demonstrate that the surface morphology and the concentration of surface -COOH groups (determined with UV-vis surface titration) on the processed PMMA-co-MAA coatings can be precisely controlled by variation of initial molar ratio of reactants in the free-radical polymerization reaction. The wettability of developed polymer surfaces also varies with macromolecular structure.

  19. 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.

  20. pH-sensitive methacrylic copolymers and the production thereof

    DOEpatents

    Mallapragada, Surya K.; Anderson, Brian C.; Bloom, Paul D.; Sheares Ashby, Valerie V.

    2007-01-09

    The present invention provides novel multi-functional methacrylic copolymers that exhibit cationic pH-sensitive behavior as well as good water solubility under acidic conditions. The copolymers are constructed from tertiary amine methacrylates and poly(ethylene glycol) containing methacrylates. The copolymers are useful as gene vectors, pharmaceutical carriers, and in protein separation applications.

  1. pH-sensitive methacrylic copolymers and the production thereof

    DOEpatents

    Mallapragada, Surya K.; Anderson, Brian C.; Bloom, Paul D.; Sheares Ashby, Valerie V.

    2006-02-14

    The present invention provides novel multi-functional methacrylic copolymers that exhibit cationic pH-sensitive behavior as well as good water solubility under acidic conditions. The copolymers are constructed from tertiary amine methacrylates and poly(ethylene glycol) containing methacrylates. The copolymers are useful as gene vectors, pharmaceutical carriers, and in protein separation applications.

  2. Acid-Base and Electrolyte Status during Normovolemic Hemodilution with Succinylated Gelatin or HES-Containing Volume Replacement Solutions in Rats

    PubMed Central

    Teloh, Johanna K.; Ferenz, Katja B.; Petrat, Frank; Mayer, Christian; de Groot, Herbert

    2013-01-01

    Background In the past, several studies have compared different colloidal replacement solutions, whereby the focus was usually on the respective colloid. We therefore systematically studied the influence of the carrier solution’s composition of five approved colloidal volume replacement solutions (Gelafundin, Gelafusal, Geloplasma, Voluven and Volulyte) on acid-base as well as electrolyte status during and following acute severe normovolemic hemodilution. The solutions differed in the colloid used (succinylated gelatin vs. HES) and in the presence and concentration of metabolizable anions as well as in their electrolyte composition. Methods Anesthetized Wistar rats were subjected to a stepwise normovolemic hemodilution with one of the solutions until a final hematocrit of 10%. Subsequent to dilution (162 min), animals were observed for an additional period (150 min). During dilution and observation time blood gas analyses were performed eight times in total. Additionally, in the Voluven and Volulyte groups as well as in 6 Gelafundin animals, electrolyte concentrations, glucose, pH and succinylated gelatin were measured in urine and histopathological evaluation of the kidney was performed. Results All animals survived without any indications of injury. Although the employed solutions differed in their respective composition, comparable results in all plasma acid-base and electrolyte parameters studied were obtained. Plasma pH increased from approximately 7.28 to 7.39, the plasma K+ concentration decreased from circa 5.20 mM to 4.80-3.90 mM and the plasma Cl− concentration rose from approximately 105 mM to 111–120 mM. Urinary analysis revealed increased excretion of K+, H+ and Cl−. Conclusions The present data suggest that the carrier solution’s composition with regard to metabolizable anions as well as K+, Ca2+ only has a minor impact on acid-base and electrolyte status after application of succinylated gelatin or HES-containing colloidal volume

  3. Photocrosslinkable Hyaluronan-Gelatin Hydrogels for Two-Step Bioprinting

    PubMed Central

    Skardal, Aleksander; Zhang, Jianxing; McCoard, Lindsi; Xu, Xiaoyu; Oottamasathien, Siam

    2010-01-01

    Bioprinting by the codeposition of cells and biomaterials is constrained by the availability of printable materials. Herein we describe a novel macromonomer, a new two-step photocrosslinking strategy, and the use of a simple rapid prototyping system to print a proof-of-concept tubular construct. First, we synthesized the methacrylated ethanolamide derivative of gelatin (GE-MA). Second, partial photochemical cocrosslinking of GE-MA with methacrylated hyaluronic acid (HA-MA) gave an extrudable gel-like fluid. Third, the new HA-MA:GE-MA hydrogels were biocompatible, supporting cell attachment and proliferation of HepG2 C3A, Int-407, and NIH 3T3 cells in vitro. Moreover, hydrogels injected subcutaneously in nude mice produced no inflammatory response. Fourth, using the Fab@Home printing system, we printed a tubular tissue construct. The partially crosslinked hydrogels were extruded from a syringe into a designed base layer, and irradiated again to create a firmer structure. The computer-driven protocol was iterated to complete a cellularized tubular construct with a cell-free core and a cell-free structural halo. Cells encapsulated within this printed construct were viable in culture, and gradually remodeled the synthetic extracellular matrix environment to a naturally secreted extracellular matrix. This two-step photocrosslinkable biomaterial addresses an unmet need for printable hydrogels useful in tissue engineering. PMID:20387987

  4. Facile "one-pot" synthesis of poly(methacrylic acid)-based hybrid monolith via thiol-ene click reaction for hydrophilic interaction chromatography.

    PubMed

    Lv, Xumei; Tan, Wangming; Chen, Ye; Chen, Yingzhuang; Ma, Ming; Chen, Bo; Yao, Shouzhuo

    2016-07-08

    A novel sol-gel "one-pot" approach in tandem with a radical-mediated thiol-ene reaction for the synthesis of a methacrylic acid-based hybrid monolith was developed. The polymerization monomers, tetramethoxysilane (TMOS) and 3-mercaptopropyl trimethoxysilane (MPTS), were hydrolyzed in high-concentration methacrylic acid solution that also served as a hydrophilic functional monomer. The resulting solution was then mixed with initiator (2, 2'-azobis (2-methylpropionamide) dihydrochloride) and porogen (urea, polyethylene glycol 20,000) in a capillary column and polymerized in water bath. The column had a uniform porous structure and a good permeability. The evaluation of the monolith was performed by separation of small molecules including nucleosides, phenols, amides, bases and Triton X-100. The calibration curves for uridine, inosine, adenosine and cytidine were determined. All the calibration curves exhibited good linear regressions (R(2)≥0.995) within the test ranges of 0.5-40μg/mL for four nucleosides. Additionaliy, atypical hydrophilic mechanism was proved by elution order from low to high according to polarity retention time increased with increases in the content of the organic solvent in the mobile phase. Further studies indicated that hydrogen bond and electrostatic interactions existed between the polar analytes and the stationary phase. This was the mechanism of retention. The excellent separation of the BSA digest showed good hydrophility of the column and indicated the potential in separation of complex biological samples. Copyright © 2016 Elsevier B.V. All rights reserved.

  5. Biodistribution and pharmacokinetics in rats and antitumor effect in various types of tumor-bearing mice of novel self-assembled gelatin-oleic acid nanoparticles containing paclitaxel.

    PubMed

    Tran, Phuong Ha-Lien; Tran, Thao Truong-Dinh; Lee, Beom-Jin

    2014-01-01

    The aim of this study was to investigate the pharmacokinetics and biodistribution in Sprague-Dawley rats, anti-tumor activity and acute toxicity in different tumor-bearing mice of novel biocompatible nanoparticles. Paclitaxel (PTX) was selected as a model drug and loaded on different tumor types and at various doses. The nanoparticles were prepared using a newly synthesized gelatin-oleic acid conjugate via self-assembly in an aqueous solution. The nanoparticles were further functionalized using folic acid (FA) as a targeting ligand for cancer. The in vivo effects of the nanoparticles were compared with the commercially available Taxol (a solution form of PTX) as a reference dosage form. The in vivo studies confirmed that nanoparticles showed improved therapeutic effects on tumors and significantly reduced the toxic effects associated with Taxol, even at the 50% lethal dose (LD50). The in vivo pharmacokinetic parameters and biodistribution of the nanoparticles containing PTX also indicated slower clearance, longer blood circulation and higher tumor selectivity. Furthermore, the functionalized nanoparticles with FA were more effective than the non-functionalized nanoparticles. Thus, the suitable properties of gelatin-oleic nanoparticles (GON) as a drug carrier and the effective targeting ligand could synergistically maximize the in vivo anti-tumor efficacy resulting in delayed tumor volume growth and hence, providing versatile strategies in cancer therapy and drug delivery.

  6. Physicochemical and functional properties of gelatin extracted from Yak skin.

    PubMed

    Xu, Mengqi; Wei, Lixin; Xiao, Yuancan; Bi, Hongtao; Yang, Hongxia; Du, Yuzhi

    2017-02-01

    Different molecular weight distribution (MWD) gelatin was extracted from Yak skin after enzymatic pretreatments and their physicochemical and functional properties (SDS-PAGE, UV-vis absorption spectra, DSC, FT-IR, Amino acid analysis, AFM, emulsibility and foamability) were analyzed. The gelatin was extracted by pepsin and got different MWD of Yak skin gelatin by controlling the enzymolysis time. The SDS-PAGE showed the MWD of the Yak skin gelatin. The UV-vis absorption turned out that the broad MWD of Yak skin gelatin had a higher maximum absorption peaks. The FT-IR and AFM indicated that the gelatin structures and microstructures changed with the change of the MWD. The broad MWD of the Yak skin gelatin had a higher denaturation temperature (TD), and it was higher than most of the other mammals and marine biological gelatin. The broad MWD gelatin also had higher imino acids (proline and hydroxyproline) contents and lower foamability and emulsibility compared to the narrow MWD gelatin. These findings, obtained for the first time for Yak skin gelatin, showed that it has great potential for application as an alternative to commercial gelatin due to its good thermotolerance, particularly in the applications of the biological materials, stabilizer of thermo-tolerant and so on. Copyright © 2016 Elsevier B.V. All rights reserved.

  7. Synthesis and characterization of a novel pH-thermo dual responsive hydrogel based on salecan and poly(N,N-diethylacrylamide-co-methacrylic acid).

    PubMed

    Wei, Wei; Qi, Xiaoliang; Liu, Yucheng; Li, Junjian; Hu, Xinyu; Zuo, Gancheng; Zhang, Jianfa; Dong, Wei

    2015-12-01

    Salecan is a water-soluble microbial polysaccharide produced by Agrobacterium sp. ZX09, a salt-tolerant strain isolated from a soil sample in our laboratory. Previous work inspired us salecan is a good candidate to fabricate hydrogels. Poly(N,N-diethylacrylamide) is one type of thermo sensitive polymer which is not investigated extremely as poly(N-isopropylacrylamide). Here, we report a novel pH-thermo dual responsive hydrogel based on salecan and poly(N,N-diethylacrylamide-co-methacrylic acid) semi-interpenetrating polymer networks (semi-IPNs). The physicochemical property of this hydrogel was investigated by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analyses (TGA), rheological test and Scanning Electron Microscopy (SEM). It was interesting that the storage modulus (G') and pore size of the hydrogel could be tuned by adjusting the content of salecan and crosslinker. The pH-thermo dual responsive property was demonstrated by swelling behavior test: the swelling ratio of the hydrogel decreased continuously as the temperature increased from 25 °C to 37 °C, while it was pH-dependent as well. Especially, when exposed to a higher temperature (37 °C) and acidic environment (pH 4.0), drug-loaded hydrogel would have a quick release. Finally, the cytotoxicity of drug-free hydrogels was investigated on A549 and HepG2 cells, results showed that it was non-toxic while the DOX released from hydrogels had comparable cytotoxicity with respect to free DOX. In conclusion, the novel salecan/poly(N,N-diethylacrylamide-co-methacrylic acid) semi-interpenetrating polymer network hydrogels were pH-thermo dual responsive and may be a promising candidate for drug delivery system.

  8. Synthesis and Characterization of Types A and B Gelatin Methacryloyl for Bioink Applications

    PubMed Central

    Lee, Bae Hoon; Lum, Nathaniel; Seow, Li Yuan; Lim, Pei Qi; Tan, Lay Poh

    2016-01-01

    Gelatin methacryloyl (GelMA) has been increasingly considered as an important bioink material due to its tailorable mechanical properties, good biocompatibility, and ability to be photopolymerized in situ as well as printability. GelMA can be classified into two types: type A GelMA (a product from acid treatment) and type B GelMA (a product from alkali treatment). In current literature, there is little research on the comparison of type A GelMA and type B GelMA in terms of synthesis, rheological properties, and printability for bioink applications. Here, we report the synthesis, rheological properties, and printability of types A and B GelMA. Types A and B GelMA samples with different degrees of substitution (DS) were prepared in a controllable manner by a time-lapse loading method of methacrylic anhydride (MAA) and different feed ratios of MAA to gelatin. Type B GelMA tended to have a slightly higher DS compared to type A GelMA, especially in a lower feed ratio of MAA to gelatin. All the type A and type B GelMA solutions with different DS exhibited shear thinning behaviours at 37 °C. However, only GelMA with a high DS had an easy-to-extrude feature at room temperature. The cell-laden printed constructs of types A and B GelMA at 20% w/v showed around 75% cell viability. PMID:28773918

  9. Gelatin in electrochromic devices

    NASA Astrophysics Data System (ADS)

    Silva, M. M.; Barbosa, P. C.; Rodrigues, L. C.; Gonçalves, A.; Costa, C.; Fortunato, E.

    2010-04-01

    A gelatin-based electrolyte has been developed and characterized by impedance spectroscopy and thermal analysis. These electrolytes are promising materials to be applied in electrochromic devices because gelatine is a material available in nature, it is cheap, easy to handle and to prepare. In this study the characterization of a solid-state electrochromic device based on gelatin is reported and results obtained suggest that this electrolyte is very attractive for electrochemical device applications. Gelatin-based electrolytes were successfully used in the assembly of prototype electrochromic devices (ECDs) and exhibited good optical density. The ECD display incorporating gelatine I and gelatine II samples presented in the visible region an average transmittance above 68% in the bleached state. After coloration the structure assembled with gelatine I composition presented an average transmittance in the visible wavelength region above 21% and 36% for gelatin II.

  10. Hydrophilic PCU scaffolds prepared by grafting PEGMA and immobilizing gelatin to enhance cell adhesion and proliferation.

    PubMed

    Shi, Changcan; Yuan, Wenjie; Khan, Musammir; Li, Qian; Feng, Yakai; Yao, Fanglian; Zhang, Wencheng

    2015-05-01

    Gelatin contains many functional motifs which can modulate cell specific adhesion, so we modified polycarbonate urethane (PCU) scaffold surface by immobilization of gelatin. PCU-g-gelatin scaffolds were prepared by direct immobilizing gelatins onto the surface of aminated PCU scaffolds. To increase the immobilization amount of gelatin, poly(ethylene glycol) methacrylate (PEGMA) was grafted onto PCU scaffolds by surface initiated atom transfer radical polymerization. Then, following amination and immobilization, PCU-g-PEGMA-g-gelatin scaffolds were obtained. Both modified scaffolds were characterized by chemical and biological methods. After immobilization of gelatin, the microfiber surface became rough, but the original morphology of scaffolds was maintained successfully. PCU-g-PEGMA-g-gelatin scaffolds were more hydrophilic than PCU-g-gelatin scaffolds. Because hydrophilic PEGMA and gelatin were grafted and immobilized onto the surface, the PCU-g-PEGMA-g-gelatin scaffolds showed low platelet adhesion, perfect anti-hemolytic activity and excellent cell growth and proliferation capacity. It could be envisioned that PCU-g-PEGMA-g-gelatin scaffolds might have potential applications in tissue engineering artificial scaffolds.

  11. Preparation and characterization of reactive blends of poly(lactic acid), poly(ethylene-co-vinyl alcohol), and poly(ethylene-co-glycidyl methacrylate)

    SciTech Connect

    Warangkhana, Phromma; Rathanawan, Magaraphan; Jana Sadhan, C.

    2015-05-22

    The ternary blends of poly(lactic acid) (PLA), poly(ethylene-co-vinyl alcohol) (EVOH), and poly(ethylene-co-glycidyl methacrylate) (EGMA) were prepared. The role of EGMA as a compatibilizer was evaluated. The weight ratio of PLA:EVOH was 80:20 and the EGMA loadings were varied from 5-20 phr. The blends were characterized as follows: thermal properties by differential scanning calorimetry, morphology by scanning electron microscopy, and mechanical properties by pendulum impact tester, and universal testing machine. The glass transition temperature of PLA blends did not change much when compared with that of PLA. The blends of PLA/EGMA and EVOH/EGMA showed EGMA dispersed droplets where the latter led to poor impact properties. However, the tensile elongation at break and tensile toughness substantially increased upon addition of EGMA to blends of PLA and EVOH. It was noted in tensile test samples that both PLA and EVOH domains fibrillated significantly to produce toughness.

  12. Preparation and characterization of reactive blends of poly(lactic acid), poly(ethylene-co-vinyl alcohol), and poly(ethylene-co-glycidyl methacrylate)

    NASA Astrophysics Data System (ADS)

    Warangkhana, Phromma; Jana Sadhan, C.; Rathanawan, Magaraphan

    2015-05-01

    The ternary blends of poly(lactic acid) (PLA), poly(ethylene-co-vinyl alcohol) (EVOH), and poly(ethylene-co-glycidyl methacrylate) (EGMA) were prepared. The role of EGMA as a compatibilizer was evaluated. The weight ratio of PLA:EVOH was 80:20 and the EGMA loadings were varied from 5-20 phr. The blends were characterized as follows: thermal properties by differential scanning calorimetry, morphology by scanning electron microscopy, and mechanical properties by pendulum impact tester, and universal testing machine. The glass transition temperature of PLA blends did not change much when compared with that of PLA. The blends of PLA/EGMA and EVOH/EGMA showed EGMA dispersed droplets where the latter led to poor impact properties. However, the tensile elongation at break and tensile toughness substantially increased upon addition of EGMA to blends of PLA and EVOH. It was noted in tensile test samples that both PLA and EVOH domains fibrillated significantly to produce toughness.

  13. Effect of electron beam irradiation on thermal and mechanical properties of poly (lactic acid)/poly (ethylene-co-glycidyl methacrylate) blend

    NASA Astrophysics Data System (ADS)

    Kumar, Ashish; Rao, T. Venkatappa; Chowdhury, S. Ray; Reddy, S. V. S. R.

    2017-06-01

    Physiochemical blend of Poly (lactic acid) (PLA)/Poly (ethylene-co-glycidyl methacrylate) (PEGMA) has been prepared by using twin-screw Micro compounder. The weight ratio of the blends was fixed at 80:20 (PLA: PEGMA). After that, the multipurpose test specimens -ASTM D638 of resulting blend and pristine PLA were prepared by injection moulding with mould temperature 32˚C. Furthermore, some test Specimens -ASTM D256 also prepared for notch impact test. The prepared samples were exposed to electron beam irradiation at different doses. These samples (un-irradiated and irradiated) were tested for mechanical and thermal properties. A detailed study is made by observing the improvement in the mechanical and thermal properties of the prepared blends with and without electron beam irradiation.

  14. 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.

  15. Improved selective cholesterol adsorption by molecularly imprinted poly(methacrylic acid)/silica (PMAA-SiO₂) hybrid material synthesized with different molar ratios.

    PubMed

    Clausen, Débora Nobile; Pires, Igor Matheus Ruiz; Tarley, César Ricardo Teixeira

    2014-11-01

    The present paper describes the synthesis of molecularly imprinted polymer - poly(methacrylic acid)/silica and reports its performance feasibility with desired adsorption capacity and selectivity for cholesterol extraction. Two imprinted hybrid materials were synthesized at different methacrylic acid (MAA)/tetraethoxysilane (TEOS) molar ratios (6:1 and 1:5) and characterized by FT-IR, TGA, SEM and textural data. Cholesterol adsorption on hybrid materials took place preferably in apolar solvent medium, especially in chloroform. From the kinetic data, the equilibrium time was reached quickly, being 12 and 20 min for the polymers synthesized at MAA/TEOS molar ratio of 6:1 and 1:5, respectively. The pseudo-second-order model provided the best fit for cholesterol adsorption on polymers, confirming the chemical nature of the adsorption process, while the dual-site Langmuir-Freundlich equation presented the best fit to the experimental data, suggesting the existence of two kinds of adsorption sites on both polymers. The maximum adsorption capacities obtained for the polymers synthesized at MAA/TEOS molar ratios of 6:1 and 1:5 were found to be 214.8 and 166.4 mg g(-1), respectively. The results from isotherm data also indicated higher adsorption capacity for both imprinted polymers regarding to corresponding non-imprinted polymers. Nevertheless, taking into account the retention parameters and selectivity of cholesterol in the presence of structurally analogue compounds (5-α-cholestane and 7-dehydrocholesterol), it was observed that the polymer synthesized at the MAA/TEOS molar ratio of 6:1 was much more selective for cholesterol than the one prepared at the ratio of 1:5, thus suggesting that selective binding sites ascribed to the carboxyl group from MAA play a central role in the imprinting effect created on MIP.

  16. Co-electrospun gelatin-poly(L-lactic acid) scaffolds: modulation of mechanical properties and chondrocyte response as a function of composition.

    PubMed

    Torricelli, Paola; Gioffrè, Michela; Fiorani, Andrea; Panzavolta, Silvia; Gualandi, Chiara; Fini, Milena; Focarete, Maria Letizia; Bigi, Adriana

    2014-03-01

    Bio-synthetic scaffolds of interspersed poly(l-lactic acid) (PLLA) and gelatin (GEL) fibers are fabricated by co-electrospinning. Tailored PLLA/GEL compositions are obtained and GEL crosslinking with genipin provides for the maintenance of good fiber morphology. Scaffold tensile mechanical properties are intermediate between those of pure PLLA and GEL and vary as a function of PLLA content. Primary human chondrocytes grown on the scaffolds exhibit good proliferation and increased values of the differentiation parameters, especially for intermediate PLLA/GEL compositions. Mineralization tests enable the deposition of a uniform layer of poorly crystalline apatite onto the scaffolds, suggesting potential applications involving cartilage as well as cartilage-bone interface tissue engineering.

  17. Curcumin delivery from poly(acrylic acid-co-methyl methacrylate) hollow microparticles prevents dopamine-induced toxicity in rat brain synaptosomes.

    PubMed

    Yoncheva, Krassimira; Kondeva-Burdina, Magdalena; Tzankova, Virginia; Petrov, Petar; Laouani, Mohamed; Halacheva, Silvia S

    2015-01-01

    The potential of poly(methyl methacrylate-co-acrylic acid) (PMMA-AA) copolymers to form hollow particles and their further formulation as curcumin delivery system have been explored. The particles were functionalized by crosslinking the acrylic acid groups via bis-amide formation with either cystamine (CYS) or 3,3'-dithiodipropionic acid dihydrazide (DTP) which simultaneously incorporated reversibility due to the presence of disulfide bonds within the crosslinker. Optical micrographs showed the formation of spherical hollow microparticles with a size ranging from 1 to 7 μm. Curcumin was loaded by incubation of its ethanol solution with aqueous dispersions of the cross-linked particles and subsequent evaporation of the ethanol. Higher loading was observed in the microparticles with higher content of hydrophobic PMMA units indicating its influence upon the loading of hydrophobic molecules such as curcumin. The in vitro release studies in a phosphate buffer showed no initial burst effect and sustained release of curcumin that correlated with the swelling of the particles under these conditions. The capacity of encapsulated and free curcumin to protect rat brain synaptosomes against dopamine-induced neurotoxicity was examined. The encapsulated curcumin showed greater protective effects in rat brain synaptosomes as measured by synaptosomal viability and increased intracellular levels of glutathione. Copyright © 2015 Elsevier B.V. All rights reserved.

  18. The use of gelatin in a multiple drug delivery system

    NASA Astrophysics Data System (ADS)

    Morgan, Abby W.

    The use of gelatin for growth factor delivery was investigated. Protein-gelatin interactions were characterized using the Biomolecular Interaction Detection (BIND) system. Acidic gelatin sheets and basic gelatin microspheres were fabricated and optimized for delivering transforming growth factor (TGF)-beta1 and bone morphogenetic protein (BMP)-2. The two delivery vehicles were then combined to produce two distinct release sequences and the effect of sequence on bone healing was determined. Using the BIND system, TGF-beta1 was found to interact more strongly with acidic gelatin than basic gelatin whereas BMP-2 only slightly favors basic gelatin over acidic gelatin. Acidic gelatin sheets were fabricated by a casting technique. These sheets successfully delivered TGF-beta1 to a rabbit ulna defect to encourage new bone formation. Basic gelatin microspheres were fabricated by the precision particle fabrication (PPF) method. Uniform drug distribution within the microspheres lead to controlled release of BMP-2 that induced bone formation within the thigh muscle of mice. The sheets and microspheres were combined to deliver both drugs either simultaneously or with a four-day delay to a rabbit calvarial defect. Both sequences encouraged more bone regeneration than empty defects by 8 weeks. Protein-gelatin interactions improved protein stability and lead to release through enzymatic degradation of the gelatin. Growth factors released either singly or in a dual system from gelatin successfully produced bone in vivo. However, single release systems require higher dosages to achieve similar healing results as observed in the dual release systems. No difference was observed between the dual release systems investigated.

  19. Extraction and characterization of gelatin from two edible Sudanese insects and its applications in ice cream making.

    PubMed

    Mariod, Abdalbasit Adam; Fadul, Hadia

    2015-07-01

    Three methods were used for extraction of gelatin from two insects, melon bug (Coridius viduatus) and sorghum bug (Agonoscelis versicoloratus versicoloratus). Extraction of insect gelatin using hot water gave higher yield reached up to 3.0%, followed by mild acid extraction which gave 1.5% and distilled water extraction which gave only 1.0%, respectively. The obtained gelatins were characterized by FTIR and the spectra of insect's gelatin seem to be similar when compared with commercial gelatin. Amide II bands of gelatins from melon and sorghum bug appeared around at 1542-1537 cm(-1). Slight differences in the amino acid composition of gelatin extracted from the two insects were observed. Ice cream was made by using 0.5% insect's gelatin and compared with that made using 0.5% commercial gelatin as stabilizing agent. The properties of the obtained ice cream produced using insects gelatin were significantly different when compared with that made using commercial gelatin.

  20. Gelation, oxygen permeability, and mechanical properties of mammalian and fish gelatin films.

    PubMed

    Avena-Bustillos, R J; Chiou, B; Olsen, C W; Bechtel, P J; Olson, D A; McHugh, T H

    2011-09-01

    The objective of this study was to evaluate the gelation, thermal, mechanical, and oxygen permeability properties of different mammalian, warm- and cold-water fish gelatin solutions and films. Mammalian gelatin solutions had the highest gel set temperatures, followed by warm-water fish and then cold-water fish gelatin solutions. These differences were related to concentrations of imino acids present in each gelatin, with mammalian gelatin having the highest and cold-water fish gelatin having the lowest concentrations. Mammalian and warm-water fish gelatin films contained helical structures, whereas cold-water fish gelatin films were amorphous. This was due to the films being dried at room temperature (23 °C), which was below or near the gelation temperatures of mammalian and warm-water fish gelatin solutions and well above the gelation temperature of cold-water fish gelatin solutions. Tensile strength, percent elongation, and puncture deformation were highest in mammalian gelatin films, followed by warm-water fish gelatin film and then by cold-water fish gelatin films. Oxygen permeability values of cold-water fish gelatin films were significantly lower than those for mammalian gelatin films. These differences were most likely due to higher moisture sorption in mammalian gelatin films, leading to higher oxygen diffusivity. Journal of Food Science © 2011 Institute of Food Technologists® No claim to original US government works.

  1. Silver-Halide Gelatin Holograms.

    DTIC Science & Technology

    1980-02-01

    PREPARATION OF R-10 TYPE BLEACHES Stock Solution A: Distilled water - 500 ml Ammonium dichromate - 20g Concentrated sulfuric acid - 14 ml Distilled water to...for the preparation of a bleach solution 5 Rinse in running water for 15 seconds Red Light 6 Soak in 0.5% ammonium dichromate for 5 minutes Red Light...those of con- ventional dichromated gelatin holograms, can be formed employing commercial silver-halide films. Major advantages of silver-halide

  2. Transition between collapsed state phases and the critical swelling of a hydrogen bonding gel: Poly(methacrylic acid-co-dimethyl acrylamide)

    NASA Astrophysics Data System (ADS)

    Yılmaz, Yaşar

    2007-06-01

    Transition between collapsed state phases and discontinuous volume phase transition for a hydrogen bonding gel, poly(methacrylic acid-co-dimethyl acrylamide), were observed by using both the volume measurements and fluorescence intensity of the pyranine fluoroprobe (8-hydroxypyrene-1,3,6-trisulfonic acid trisodium salt) bonded to the gel by means of electrostatic interactions. In the collapsed state, while there is no appreciable change in the volume of the gel, a considerable variation in the fluorescence intensity occurred around 30°C signaling a second order phase transition between collapsed state phases, from relatively frozen to a fluctuating phase. Our analysis of the data around 30°C indicates that the critical point of gel volume transition belongs to the so-called mean-field universality class, as predicted in Onuki [Phys. Rev. A 38, 2192 (1988)] and by Golubovic and Lubensky [Phys. Rev. Lett. 63, 1082 (1989)]. The relaxation time for the equilibrium swelling critically depends on the temperature and diverges near 60°C, where both fluorescence intensity and the volume of the gel change drastically and indicate the discontinuous volume phase transition. The swelling kinetics of the critical gel during the discontinuous volume phase transition can be modeled best with the first term in the expansion of the Li-Tanaka equation for a long initial period of the swelling time.

  3. Co-localisation of advanced glycation end products and d-β-aspartic acid-containing proteins in gelatinous drop-like corneal dystrophy

    PubMed Central

    Oshika, Tetsuro; Takazawa, Yutaka; Fukayama, Masashi; Fujii, Noriko

    2012-01-01

    Purpose Gelatinous drop-like corneal dystrophy (GDLD), also known as familial subepithelial corneal amyloidosis, is an autosomal recessive disorder that causes progressive corneal opacity due to accumulation of amyloid fibrils in the corneal stroma. Genetic analyses have revealed that a mutation in membrane component chromosome 1 surface marker 1 gene is responsible for GDLD. However, the mechanism of amyloid formation in the corneal stroma remains unclear. The present study attempted to reveal the role of advanced glycation end products (AGE) and d-amino acids in amyloid formation in GDLD. Methods Informed consent was obtained from five patients with GDLD, three patients with bullous keratopathy and three patients with interstitial keratitis and all the specimens were analysed. Localisation of amyloid fibrils was analysed using Congo-red and thioflavin T staining. In addition, the localisation of AGE (Nɛ-carboxy(methyl)-l-lysine, pyrraline and pentosidine) and d-β-aspartic acid-containing proteins, a major form of d-amino acid-containing proteins, was analysed immunohistochemically. Results In all GDLD specimens, strong immunoreactivity to AGE and d-β-aspartic acid-containing proteins was detected in the subepithelial amyloid-rich region. In contrast, amyloid fibrils, AGE, or d-amino acid-containing proteins were slightly detected in the corneal stroma of patients with bullous keratopathy and interstitial keratitis. Conclusions Abnormally accumulated proteins rich in AGE and d-β-aspartic acid co-localise in the amyloid lesions in GDLD. These results indicate that non-enzymatic post-translational modifications of proteins, including AGE formation and isomerisation of aspartyl residues, will be the cause as well as the result of amyloid fibril formations in GDLD. PMID:22694960

  4. The influence of the copolymer composition on the diltiazem hydrochloride release from a series of pH-sensitive poly[(N-isopropylacrylamide)-co-(methacrylic acid)] hydrogels.

    PubMed

    Díez-Peña, Eva; Frutos, Paloma; Frutos, Gloria; Quijada-Garrido, Isabel; Barrales-Rienda, José Manuel

    2004-04-20

    A series of poly[(N-isopropylacrylamide)-co-(methacrylic acid)] (P[(N-iPAAm)-co-(MAA)]) hydrogels was investigated to determine the composition that exhibits a better pH-modulated release of diltiazem hydrochloride (DIL.HCl). For this purpose hydrogel slabs were loaded with DIL.HCl by the immersion method, and its release under acidic medium (0.1N HCl, pH 1.2) and in phosphate buffer pH 7.2, using United States Pharmacopeia (USP) 24 Apparatus 1, was investigated. According to the results from the slabs, copolymers with 85% mol N-iPAAm content were selected to prepare tablets with different particle size. The effect of pH and particle size changes on DIL.HCl release from these last hydrogel tablets was investigated by a stepwise pH variation of the dissolution medium. The amount of DIL.HCl released from high N-iPAAm content copolymer slabs under acidic pH medium was not only very low but it was also released at a slow rate. In the 85% N-iPAAm tablets, significant differences between and within release profiles were found as a function of particle size and pH, respectively. A relationship between particle size and release rate has been found. The lower DIL.HCl release at acidic pH from enriched N-iPAAm copolymers is interpreted by a cooperative thermal- and pH-collapse. Although for the whole range of copolymer composition a dependence of the equilibrium of swelling on the pH was found, DIL.HCl release experiments indicated that hydrogels with 85% mol N-iPAAm are the more adequate to be used for modulated drug delivery systems. Additionally, the particle size of the tablet can be used to tailor the release rate.

  5. Combining poly (methacrylic acid-co-ethylene glycol dimethacrylate) monolith microextraction and octadecyl phosphonic acid-modified zirconia-coated CEC with field-enhanced sample injection for analysis of antidepressants in human plasma and urine.

    PubMed

    Wei, Fang; Fan, Jin; Zheng, Ming-Ming; Feng, Yu-Qi

    2010-01-01

    A method based on poly (methacrylic acid-co-ethylene glycol dimethacrylate) monolith microextraction and octadecylphosphonic acid-modified zirconia-coated CEC followed by field-enhanced sample injection preconcentration technique was proposed for sensitive CE-UV analysis of six antidepressants (doxepin, clozapine, imipramine, paroxetine, fluoxetine and chlorimipramine) in human plasma and urine. A poly(methacrylic acid-co-ethylene glycol dimethacrylate) monolithic capillary column was introduced for the extraction of antidepressants from urine and plasma samples. The hydrophobic main chains and acidic pendant groups of the monolithic column make it a superior material for extraction of basic analytes from aqueous matrix. After extraction, the desorption solvent, which normally provided an excellent medium to ensure direct compatibility for field-enhanced sample injection in CE, was analyzed by CE directly. By the use of alkylphosphonate-modified zirconia-coated CEC for separation of the basic compounds of antidepressants, high separation efficiency and resolution were achieved because that both hydrophobic interaction between analytes and alkylphosphonate-modified zirconia coat and electrophoretic effect work on the separation of antidepressants. The best separation was achieved using a buffer composed of 0.3 M ammonium acetate (adjusted to pH 4.5 with 1 M acetic acid) and 35% ACN v/v, with a temperature and voltage of 20 degrees C and 20 kV, respectively. By applying both preconcentration procedures, LODs of 11.4-51.5 and 3.7-17.0 microg/L were achieved for the six antidepressants in human plasma and urine, respectively. Excellent method of reproducibility was found over a linear range of 50-5000 microg/L in plasma and urine sample.

  6. Rapid Determination of Amino Acids in Beer, Red Wine, and Donkey-Hide Gelatin by Gradient Elution of HPLC: From Micellar Liquid Chromatography to High Submicellar Liquid Chromatography.

    PubMed

    Xie, Yunfei; Luo, Tian; Yang, Jing; Dong, Yuming

    2017-07-31

    Amino acids (AAs) in beer, red wine, and donkey-hide gelatin were rapidly determined by gradient LC elution from micellar LC to high submicellar LC. Mobile phase A was a 0.075 M sodium dodecyl sulfate solution containing 20 mM ammonium acetate with a pH value adjusted to 3.5 with acetic acid solution, and mobile phase B was acetonitrile. Optimized chromatographic conditions were as follows: mobile phase B increased from 25 to 60% (v/v) in 30 min and the use of a Venusil XBP C18 column (5 µm, 250 × 4.6 mm) as the stationary phase, with a column temperature of 35°C, flow rate of 1.2 mL/min, and detection wavelength of 266 nm. The results indicated good linearity (r² ≥ 0.9924). The intraday precision of the retention time was RSD ≤ 1.1%, whereas interday was RSD ≤ 3.2%; intraday precision of the peak area was RSD ≤ 3.3%, whereas interday was RSD ≤ 4.9%. The range of recovery was 94.6-102.4%. The RSDs of the retention time for the AAs for the different samples were 0.04-0.31%.

  7. Three-Dimensional Printed Shape Memory Objects Based on an Olefin Ionomer of Zinc-Neutralized Poly(ethylene-co-methacrylic acid).

    PubMed

    Zhao, Zhiyang; Peng, Fang; Cavicchi, Kevin A; Cakmak, Mukerrem; Weiss, R A; Vogt, Bryan D

    2017-08-16

    Three-dimensional printing enables the net shape manufacturing of objects with minimal material waste and low tooling costs, but the functionality is generally limited by available materials, especially for extrusion-based printing, such as fused deposition modeling (FDM). Here, we demonstrate shape memory behavior of 3D printed objects with FDM using a commercially available olefin ionomer, Surlyn 9520, which is zinc-neutralized poly(ethylene-co-methacrylic acid). The initial fixity for 3D printed and compression-molded samples was similar, but the initial recovery was much lower for the 3D printed sample (R = 58%) than that for the compression-molded sample (R = 83%). The poor recovery in the first cycle is attributed to polyethylene crystals formed during programming that act to resist the permanent network recovery. This effect is magnified in the 3D printed part due to the higher strain (lower modulus in the 3D printed part) at a fixed programming stress. The fixity and recovery in subsequent shape memory cycles are greater for the 3D printed part than for the compression-molded part. Moreover, the programmed strain can be systematically modulated by inclusion of porosity in the printed part without adversely impacting the fixity or recovery. These characteristics enable the direct formation of complex shapes of thermoplastic shape memory polymers that can be recovered in three dimensions with the appropriate trigger, such as heat, through the use of FDM as a 3D printing technology.

  8. Poly(methacrylic acid-ethylene glycol dimethacrylate) monolith in-tube solid phase microextraction coupled to high performance liquid chromatography and analysis of amphetamines in urine samples.

    PubMed

    Fan, Yi; Feng, Yu-Qi; Zhang, Jian-Tao; Da, Shi-Lu; Zhang, Min

    2005-05-13

    In-tube solid-phase microextraction (SPME) based on a poly(methacrylic acid-ethylene glycol dimethacrylate) monolithic capillary column was investigated for the extraction of amphetamine, methamphetamine and their methylenedioxy derivatives. The monolithic capillary column showed high extraction efficiency towards target analytes, which could be attributed to its larger loading amount of extraction phase than conventional open-tubular extraction capillaries and the convective mass transfer procedure provided by its monolithic structure. The extraction mechanism was studied, and the results indicated that the extraction process of the target analytes was involved with hydrophobic interaction and ion-exchange interaction. The polymer monolith in-tube SPME-HPLC system with UV detection was successfully applied to the determination of amphetamine, methamphetamine and their methylenedioxy derivatives in urine samples, yielding the detection limits of 1.4 - 4.0 ng/mL. Excellent method reproducibility (RSD < 2.9%) was found over a linear range of 0.05-5 microg/mL, and the time for the whole analysis was only approximately 25 min. The monolithic capillary column was reusable in coping with the complicated urine samples.

  9. Catalase purification from rat liver with iron-chelated poly(hydroxyethyl methacrylate-N-methacryloyl-(l)-glutamic acid) cryogel discs.

    PubMed

    Göktürk, Ilgım; Perçin, Işık; Denizli, Adil

    2016-08-17

    In this study, iron-chelated poly(hydroxyethyl methacrylate-N-methacryloyl-(l)-glutamic acid) (PHEMAGA/Fe(3+)) cryogel discs were prepared. The PHEMAGA/Fe(3+) cryogel discs were characterized by elemental analysis, scanning electron microscopy, Fourier transform infrared spectroscopy, swelling tests, and surface area measurements. The PHEMAGA/Fe(3+) cryogel discs had large pores ranging from 10 to 100 µm with a swelling degree of 9.36 g H2O/g cryogel. Effects of pH, temperature, initial catalase concentration, and flow rate on adsorption capacity of the PHEMAGA/Fe(3+) cryogel discs were investigated. Maximum catalase adsorption capacity (62.6 mg/g) was obtained at pH 7.0, 25°C, and 3 mg/ml initial catalase concentration. The PHEMAGA/Fe(3+) cryogel discs were also tested for the purification of catalase from rat liver. After tissue homogenization, purification of catalase was performed using the PHEMAGA/Fe(3+) cryogel discs and catalase was obtained with a yield of 54.34 and 16.67 purification fold.

  10. Preparation of methacrylic acid copolymer S nano-fibers using a solvent-based electrospinning method and their application in pharmaceutical formulations.

    PubMed

    Hamori, Mami; Shimizu, Yuki; Yoshida, Kaori; Fukushima, Keizo; Sugioka, Nobuyuki; Nishimura, Asako; Naruhashi, Kazumasa; Shibata, Nobuhito

    2015-01-01

    In this study, we applied an electrospinning (ES) method, which is mainly employed in the textile industry, to the field of pharmaceuticals. We developed and modified an ES instrument and then utilized it to produce methacrylic acid copolymer S (MAC) nano-fibers to prepare tablets. By attaching a conductor rod made from stainless steel to the central part of the nano-fiber-collection plate of the ES apparatus, a MAC nano-fiber sheet could be produced effectively. In addition, we studied various operating conditions for this new ES method, including needle gauge, voltage between the electrodes, distance between the needle and nano-fiber-collection plate and the flow rate of MAC polymer solution, but these had no significant effect on the diameter of MAC nano-fibers. On the other hand, the viscosity (concentration) of MAC polymer solution and permittivity of solvent used to dilute MAC were closely related to the mean diameter of the nano-fibers. Tableting of MAC nano-fibers was performed using a tableting machine without lubricants, and addition of Tween 20 to the tablets enabled regulation of the release profile of a water-soluble drug. The modified ES method reported here is a useful technique for the controlled-release of drugs and has wide-ranging potential for pharmaceutical applications.

  11. Lower cytotoxicity, high stability, and long-term antibacterial activity of a poly(methacrylic acid)/isoniazid/rifampin nanogel against multidrug-resistant intestinal Mycobacterium tuberculosis.

    PubMed

    Chen, Tao; Li, Qiang; Guo, Lina; Yu, Li; Li, Zhenyan; Guo, Huixin; Li, Haicheng; Zhao, Meigui; Chen, Liang; Chen, Xunxun; Zhong, Qiu; Zhou, Lin; Wu, Ting

    2016-01-01

    To overcome the undesirable side effects and reduce the cytotoxicity of isoniazid (INH) and rifampin (RMP) in the digestive tract, a poly(methacrylic acid) (PMAA) nanogel was developed as a carrier of INH and RMP. This PMAA/INH/RMP nanogel was prepared as a treatment for intestinal tuberculosis caused by multidrug-resistant Mycobacterium tuberculosis (MTB). The morphology, size, and in vitro release properties were evaluated in a simulated gastrointestinal medium, and long-term antibacterial performance, cytotoxicity, stability, and activity of this novel PMAA/INH/RMP nanogel against multidrug-resistant MTB in the intestine were investigated. Our results indicate that the PMAA/INH/RMP nanogel exhibited extended antibacterial activity by virtue of its long-term release of INH and RMP in the simulated gastrointestinal medium. Further, this PMAA/INH/RMP nanogel exhibited lower cytotoxicity than did INH or RMP alone, suggesting that this PMAA/INH/RMP nanogel could be a more useful dosage form than separate doses of INH and RMP for intestinal MTB. The novel aspects of this study include the cytotoxicity study and the three-phase release profile study, which might be useful for other researchers in this field. Crown Copyright © 2015. Published by Elsevier B.V. All rights reserved.

  12. Surface characterization of poly(vinyl chloride) urinary catheters functionalized with acrylic acid and poly(ethylene glycol) methacrylate using gamma-radiation

    NASA Astrophysics Data System (ADS)

    Islas, Luisa; Ruiz, Juan-Carlos; Muñoz-Muñoz, Franklin; Isoshima, Takashi; Burillo, Guillermina

    2016-10-01

    Poly(vinyl chloride) (PVC) urinary catheters were modified with either a single or binary graft of acrylic acid (AAc) and/or poly(ethylene glycol) methacrylate (PEGMA) using gamma-radiation from 60Co to obtain PVC-g-AAc, PVC-g-PEGMA, [PVC-g-AAc]-g-PEGMA, and [PVC-g-PEGMA]-g-AAc copolymers. The outer and inner surfaces of the modified catheters were characterized using scanning electron microscopy (SEM), confocal laser microscopy (CLM) and X-ray photoelectron spectroscopy (XPS). The XPS analyses, by examining the correlation between the variation of the C1s and O1s content at the catheter's surface, revealed that the catheter's surfaces were successfully grafted with the chosen compounds, with those that were binary grafted showing a slightly more covered surface as was evidenced by the disappearance of PVC's Cl peak. The SEM and CLM analyses revealed that catheters that had been grafted with PEGMA had a rougher outer surface as compared to those that had only been grafted with AAc. In addition, these imaging techniques showed that the inner surface of the singly grafted catheters, whether they had been grafted with AAc or PEGMA, retained some smoothness at the analyzed grafting percentages, while the binary grafted catheters showed many protuberances and greater roughness on both outer and inner surfaces.

  13. Microfluidic immunosensor based on mesoporous silica platform and CMK-3/poly-acrylamide-co-methacrylate of dihydrolipoic acid modified gold electrode for cancer biomarker detection.

    PubMed

    Regiart, Matías; Fernández-Baldo, Martin A; Villarroel-Rocha, Jhonny; Messina, Germán A; Bertolino, Franco A; Sapag, Karim; Timperman, Aaron T; Raba, Julio

    2017-04-22

    We report a hybrid glass-poly (dimethylsiloxane) microfluidic immunosensor for epidermal growth factor receptor (EGFR) determination, based on the covalent immobilization of anti-EGFR antibody (anti-EGFR) on amino-functionalized mesoporous silica (AMS) retained in the central channel of a microfluidic device. The synthetized AMS was characterized by N2 adsorption-desorption isotherm, scanning electron microscopy (SEM), energy dispersive spectrometry (EDS) and infrared spectroscopy. The cancer biomarker was quantified in human serum samples by a direct sandwich immunoassay measuring through a horseradish peroxidase-conjugated anti-EGFR. The enzymatic product was detected at -100 mV by amperometry on a sputtering gold electrode, modified with an ordered mesoporous carbon (CMK-3) in a matrix of poly-acrylamide-co-methacrylate of dihydrolipoic acid (poly(AC-co-MDHLA)) through in situ copolymerization. CMK-3/poly(AC-co-MDHLA)/gold was characterized by cyclic voltammetry, EDS and SEM. The measured current was directly proportional to the level of EGFR in human serum samples. The linear range was from 0.01 ng mL(-1) to 50 ng mL(-1). The detection limit was 3.03 pg mL(-1), and the within- and between-assay coefficients of variation were below 5.20%. The microfluidic immunosensor is a very promising device for the diagnosis of several kinds of epithelial origin carcinomas.

  14. Gamma-radiation-induced grafting of binary mixture of methacrylic acid and 4-vinyl pyridine onto Teflon-FEP film as an effective polar membrane for separation processes

    NASA Astrophysics Data System (ADS)

    Kaur, Inderjeet; Rattan, Sunita; Chauhan, Sandeep; Gupta, Nitika

    2010-05-01

    Ionic bifunctional membranes have been synthesized by grafting binary mixture of methacrylic acid (MAAc) and 4-vinyl pyridine (4-VP) onto Teflon-FEP film by pre-irradiation method. Optimum conditions pertaining to maximum percentage of grafting were evaluated as a function of different reaction parameters. Maximum percentage of grafting of binary mixture (MAAc-co-4-VP) (71.29%) was obtained at an optimum total dose of 54.48 kGy and the total concentration was 9.49 mol/L ([4-VP] = 0.07 mol/L and [MAAc ] = 9.42 mol/L) in 5 ml of water. The effect of alcohols as additives to the reaction medium on percent grafting of the binary mixture has also been studied. The membranes were characterized by FTIR spectroscopy, scanning electron microscopy and thermogravimetric analysis. Swelling studies of the membranes were performed in different solvents such as water, benzene, carbon tetrachloride and dimethyl formamide (DMF). Maximum swelling was observed in DMF with minimum swelling in benzene. Metal ion (Cu 2+, Ni 2+ and Fe 2+) uptake studies show better affinity for Fe 2+ ions. Conductance measurements in different aqueous salt solution showed that these membranes have affinity for Na +/K + ions and Cl - ions and hence can be used in desalination/separation processes for the separation of both type of cationic and anionic ions.

  15. One-Way Multishape-Memory Effect and Tunable Two-Way Shape Memory Effect of Ionomer Poly(ethylene-co-methacrylic acid).

    PubMed

    Lu, Lu; Li, Guoqiang

    2016-06-15

    Reversible elongation by cooling and contraction by heating, without the need for repeated programming, is well-known as the two-way shape-memory effect (2W-SME). This behavior is contrary to the common physics-contraction when cooling and expansion when heating. Materials with such behavior may find many applications in real life, such as self-sufficient grippers, fastening devices, optical gratings, soft actuators, and sealant. Here, it is shown that ionomer Surlyn 8940, a 50-year old polymer, exhibits both one-way multishape-memory effects and tunable two-way reversible actuation. The required external tensile stress to trigger the tunable 2W-SME is very low when randomly jumping the temperatures within the melting transition window. With a proper one-time programming, "true" 2W-SME (i.e., 2W-SME without the need for an external tensile load) is also achieved. A long training process is not needed to trigger the tunable 2W-SME. Instead, a proper one-time tensile programming is sufficient to trigger repeated and tunable 2W-SME. Because the 2W-SME of the ionomer Surlyn is driven by the thermally reversible network, here crystallization and melting transitions of the semicrystalline poly(ethylene-co-methacrylic acid), it is believed that a class of thermally reversible polymers should also exhibit tunable 2W-SMEs.

  16. One-Pot Synthesis of Hydrophilic Superparamagnetic Fe3O4/Poly(methyl methacrylate-acrylic acid) Composite Nanoparticles with High Magnetization.

    PubMed

    Ma, Shaohua; Lan, Fang; Yang, Qi; Xie, Liqin; Wu, Yao; Gu, Zhongwei

    2015-01-01

    Uniform superparamagnetic Fe3O4/poly(methyl methacrylate-acrylic acid) (P(MMA-AA)) composite nanoparticles with high saturation magnetization and good hydrophilicity were successfully and directly synthesized via a facile one-pot miniemulsion polymerization approach. The mixture of the ferrofluids, MMA and AA monomers, surfactants and initiator was co-sonicated and emulsified to prepare stable miniemulsion for polymerization. The as-prepared products were characterized by SEM, TEM, FT-IR, XRD, TGA and VSM. The results of SEM indicated that the morphology of the Fe3O4/P(MMA-AA) composite nanoparticles all assumed near spherical geometry with diameters about 60 nm, 60 nm, and 100 nm respectively corresponding to the weight ratios of Fe3O4 to MMA and AA at 1:8, 1:4, and 1:2. The TEM images implied that the Fe3O4/P(MMA-AA) composite nanoparticles showed a perfect core-shell structure with a polymeric shell of about 2 nm thickness and a core encapsulating uniform and close packed Fe3O4 nanoparticles. TGA and VSM showed that the Fe3O4/P(MMA-AA) composite nanoparticles with a maximum saturation magnetization up to 45 emu g(-1) corresponding to the magnetite content of 78% exhibited superparamagntism. The hydrophilic modification and the high saturation magnetization impart a promising potential for biomedical applications to the as-synthesized composite nanoparticles.

  17. Determination of N-methylcarbamate pesticides in vegetables by poly(methacrylic acid-co-ethylene glycol dimethacrylate) monolith microextraction coupled with high performance liquid chromatography.

    PubMed

    Ma, Huihui; Feng, Wei; Tian, Miaomiao; Jia, Qiong

    2013-06-15

    A simple, rapid and sensitive method for simultaneous determination of three N-methylcarbamate pesticides (carbaryl, pirimicarb, and isoprocarb) in vegetables was developed by coupling polymer monolith microextraction (PMME) to high-performance liquid chromatography (HPLC). A poly(methacrylic acid-co-ethylene glycol dimethacrylate) monolith was selected as the extraction medium for PMME. To achieve optimum extraction performance, several parameters were investigated, including desorption solvent, desorption flow rate, sample flow rate, sample volume, sample pH values, inorganic salt and organic solvent content of the sample solution. Under the optimum experimental conditions, the method provides an acceptable linearity (5-5000μg/kg), low limits of detection (0.36-2.6μg/kg), good precision (intra-day relative standard deviations<2.53%, inter-day relative standard deviations <6.36%). Finally, the developed method was successfully applied to the determination of N-methylcarbamate pesticides in vegetables, and the trueness was evaluated by recovery experiments. The obtained relative recoveries were in the range of 70.4-98.5%. This PMME method integrates sample extraction, purification, and preconcentration of analytes into one single step and it also has several advantages such as solvent-free extraction, small sample volume, high enrichment, convenience, and flexibility operation.

  18. 2-hydroxyethyl metahcrylate/gelatin based superporous hydrogels for tissue regeneration

    NASA Astrophysics Data System (ADS)

    Tomić, Simonida Lj.; Babić, Marija M.; Vuković, Jovana S.; Perišić, Marija D.; Filipović, Vuk V.; Davidović, Sladjana Z.; Filipović, Jovanka M.

    2016-05-01

    In this study, superporous hydrogels were synthesized by free radical polymerization of 2-hydroxyethyl methacrylate without and in the presence of gelatin. Highly porous hydrogel structures were obtained by two different techniques: using a gas blowing agent, sodium bicarbonate, and a cryogenic treatment followed by freeze-drying. After the gel synthesis, gelatin molecules were covalently immobilised onto PHEMA via glytaraldehyde activation. All samples were characterized for morphological, mechanical, swelling and antibacterial properties. The results obtained show that samples with gelatin show better properties in comparison with PHEMA samples, which make these materials highly attractive for developing hydrogel scaffolds for tissue regeneration.

  19. Comparison of the wound healing efficacy of polyglycolic acid sheets with fibrin glue and gelatin sponge dressings in a rat cranial periosteal defect model

    PubMed Central

    Koshinuma, Shinya; Murakami, Shoko; Noi, Masaharu; Murakami, Takuya; Mukaisho, Ken-Ichi; Sugihara, Hiroyuki; Yamamoto, Gaku

    2016-01-01

    Oral surgical procedures occasionally require removal of the periosteum due to lesions, and these raw bone surfaces are prone not only to infection but also to scar formation during secondary healing. The objective of this study was to identify successful methods for reconstruction using periosteal defect dressings. We created 1-cm2 defects in the skin and cranial periosteum of 10-week-old male Wistar rats under isoflurane anesthesia. The animals were assigned to three defect treatment groups: (1) polyglycolic acid sheets with fibrin glue dressing (PGA-FG), (2) Spongel® gelatin sponge dressing (GS), and (3) open wound (control). Postoperative wound healing was histologically evaluated at 2, 4, and 6 weeks. The moist conditions maintained by the GS and PGA-FG treatments protected the bone surface from the destructive effects of drying and infection. Complete wound healing was observed in the GS group but not for all animals in the PGA-FG and control groups. Histologically, osteoblast proliferation on bone surfaces and complete epithelialization with adnexa were observed in the GS group at 6 weeks after surgery. In contrast, PGA sheets that had not been absorbed inhibited osteoblast proliferation and delayed wound healing in the PGA-FG group. Wound surface dressings maintain a moist environment that promotes wound healing, but PGA materials may not be suitable for cases involving exposed periosteum or bone surfaces due to the observed scar formation and foreign-body reaction. PMID:27384972

  20. Investigation of the Viability, Adhesion, and Migration of Human Fibroblasts in a Hyaluronic Acid/Gelatin Microgel-Reinforced Composite Hydrogel for Vocal Fold Tissue Regeneration.

    PubMed

    Heris, Hossein K; Daoud, Jamal; Sheibani, Sara; Vali, Hojatollah; Tabrizian, Maryam; Mongeau, Luc

    2016-01-21

    The potential use of a novel scaffold biomaterial consisting of cross-linked hyaluronic acid (HA)-gelatin (Ge) composite microgels is investigated for use in treating vocal fold injury and scarring. Cell adhesion integrins and kinematics of cell motion are investigated in 2D and 3D culture conditions, respectively. Human vocal fold fibroblast (hVFF) cells are seeded on HA-Ge microgels attached to a HA hydrogel thin film. The results show that hVFF cells establish effective adhesion to HA-Ge microgels through the ubiquitous expression of β1 integrin in the cell membrane. The microgels are then encapsulated in a 3D HA hydrogel for the study of cell migration. The cells within the HA-Ge microgel-reinforced composite hydrogel (MRCH) scaffold have an average motility speed of 0.24 ± 0.08 μm min(-1) . The recorded microscopic images reveal features that are presumably associated with lobopodial and lamellipodial cell migration modes within the MRCH scaffold. Average cell speed during lobopodial migration is greater than that during lamellipodial migration. The cells move faster in the MRCH than in the HA-Ge gel without microgels. These findings support the hypothesis that HA-Ge MRCH promotes cell adhesion and migration; thereby they constitute a promising biomaterial for vocal fold repair.

  1. Hyaluronic acid doped-poly(3,4-ethylenedioxythiophene)/chitosan/gelatin (PEDOT-HA/Cs/Gel) porous conductive scaffold for nerve regeneration.

    PubMed

    Wang, Shuping; Guan, Shui; Zhu, Zhibo; Li, Wenfang; Liu, Tianqing; Ma, Xuehu

    2017-02-01

    Conducting polymer, as a "smart" biomaterial, has been increasingly used to construct tissue engineered scaffold for nerve tissue regeneration. In this study, a novel porous conductive scaffold was prepared by incorporating conductive hyaluronic acid (HA) doped-poly(3,4-ethylenedioxythiophene) (PEDOT-HA) nanoparticles into a chitosan/gelatin (Cs/Gel) matrix. The physicochemical characteristics of Cs/Gel scaffold with 0-10wt% PEDOT-HA were analyzed and the results indicated that the incorporation of PEDOT-HA into scaffold increased the electrical and mechanical properties while decreasing the porosity and water absorption. Moreover, in vitro biodegradation of scaffold displayed a declining trend with the PEDOT-HA content increased. About the biocompatibility of conductive scaffold, neuron-like rat phaeochromocytoma (PC12) cells were cultured in scaffold to evaluate cell adhesion and growth. 8% PEDOT-HA/Cs/Gel scaffold had a higher cell adhesive efficiency and cell viability than the other conductive scaffolds. Furthermore, cells in the scaffold with 8wt% PEDOT-HA expressed higher synapse growth gene of GAP43 and SYP compared with Cs/Gel control group. These results suggest that 8%PEDOT-HA/Cs/Gel scaffold is an attractive cell culture conductive substrate which could support cell adhesion, survival, proliferation, and synapse growth for the application in nerve tissue regeneration. Copyright © 2016 Elsevier B.V. All rights reserved.

  2. Investigation of the Viability, Adhesion, and Migration of Human Fibroblasts in a Hyaluronic acid/Gelatin Microgel-Reinforced Composite Hydrogel for Vocal Fold Tissue Regeneration

    PubMed Central

    Heris, Hossein K.; Daoud, Jamal; Sheibani, Sara; Vali, Hojatollah; Tabrizian, Maryam; Mongeau, Luc

    2016-01-01

    The potential use of a novel scaffold biomaterial consisting of crosslinked hyaluronic acid (HA)–gelatin (Ge) composite microgels was investigated for use in treating vocal fold injury and scarring. Cell adhesion integrins and kinematics of cell motion were investigated in two- and three-dimensional culture conditions, respectively. Human vocal fold fibroblast (hVFF) cells were seeded on HA–Ge microgels attached to a HA hydrogel thin film. The results showed that hVFF cells established effective adhesion to HA–Ge microgels through the ubiquitous expression of β1 integrin in the cell membrane. The microgels were then encapsulated in a three-dimensional HA hydrogel for the study of cell migration. The cells within the HA–Ge microgel-reinforced composite hydrogel (MRCH) scaffold had an average motility speed of 0.24±0.08 μm/minute. The recorded microscopic images revealed features that are presumably associated with lobopodial and lamellipodial cell migration modes within the MRCH scaffold. Average cell speed during lobopodial migration was greater than that during lamellipodial migration. The cells moved faster in the MRCH than in the HA–Ge gel without microgels. These findings support the hypothesis that HA–Ge MRCH promote cell adhesion and migration; thereby they constitute a promising biomaterial for vocal fold repair. PMID:26501384

  3. In situ demonstration of Fluoro-Turquoise conjugated gelatin for visualizing brain vasculature and endothelial cells and their characterization in normal and kainic acid exposed animals.

    PubMed

    Sarkar, Sumit; Raymick, James; Paule, Merle G; Schmued, Larry

    2013-10-15

    The present study describes a new method for the visualization of the vasculature lumen and endothelial cells and characterizes their morphology in the brains of normal and kainic acid (KA) treated rats. Herein, labeling was accomplished using Fluoro-Turquoise (FT), a novel reactive blue fluorochrome conjugated to gelatin. Strong blue fluorescence was observed throughout the brain vasculature following intra-cardiac perfusion with FT-gel in normal animals. However, in the brains of KA treated rats (hippocampus, midline and ventral thalamus, piriform cortex), the vascular lumen was typically constricted, sclerotic and only faintly stained. The advantages of FT-gel over other markers can be attributed to its unique chemical and spectral properties. Specifically, Fluoro-Turquoise is a very bright blue UV excitable dye that does not bleed through when visualized using other filters, making it ideal for multiple immunofluorescent labeling studies. Its brightness at low magnification also makes it ideal for low magnification whole brain imaging. Compared to alternative techniques for visualizing blood vessels, such as India ink, fluorescent dye-conjugated dextran, the corrosion technique, endothelial cell markers and lectins, the present method results in excellent visualization of blood vessels.

  4. Dual Function of Glucosamine in Gelatin/Hyaluronic Acid Cryogel to Modulate Scaffold Mechanical Properties and to Maintain Chondrogenic Phenotype for Cartilage Tissue Engineering.

    PubMed

    Chen, Chih-Hao; Kuo, Chang-Yi; Wang, Yan-Jie; Chen, Jyh-Ping

    2016-11-23

    Glucosamine (GlcN) fulfills many of the requirements as an ideal component in scaffolds used in cartilage tissue engineering. The incorporation of GlcN in a gelatin/hyaluronic acid (GH) cryogel scaffold could provide biological cues in maintaining the phenotype of chondrocytes. Nonetheless, substituting gelatin with GlcN may also decrease the crosslinking density and modulate the mechanical properties of the cryogel scaffold, which may be beneficial as physical cues for chondrocytes in the scaffold. Thus, we prepared cryogel scaffolds containing 9% GlcN (GH-GlcN9) and 16% GlcN (GH-GlcN16) by carbodiimide-mediated crosslinking reactions at -16 °C. The crosslinking density and the mechanical properties of the cryogel matrix could be tuned by adjusting the content of GlcN used during cryogel preparation. In general, incorporation of GlcN did not influence scaffold pore size and ultimate compressive strain but increased porosity. The GH-GlcN16 cryogel showed the highest swelling ratio and degradation rate in hyaluronidase and collagenase solutions. On the contrary, the Young's modulus, storage modulus, ultimate compressive stress, energy dissipation level, and rate of stress relaxation decreased by increasing the GlcN content in the cryogel. The release of GlcN from the scaffolds in the culture medium of chondrocytes could be sustained for 21 days for GH-GlcN16 in contrast to only 7 days for GH-GlcN9. In vitro cell culture experiments using rabbit articular chondrocytes revealed that GlcN incorporation affected cell proliferation, morphology, and maintenance of chondrogenic phenotype. Overall, GH-GlcN16 showed the best performance in maintaining chondrogenic phenotype with reduced cell proliferation rate but enhanced glycosaminoglycans (GAGs) and type II collagen (COL II) secretion. Quantitative real-time polymerase chain reaction also showed time-dependent up-regulation of cartilage-specific marker genes (COL II, aggrecan and Sox9) for GH-GlcN16. Implantation of

  5. Dual Function of Glucosamine in Gelatin/Hyaluronic Acid Cryogel to Modulate Scaffold Mechanical Properties and to Maintain Chondrogenic Phenotype for Cartilage Tissue Engineering

    PubMed Central

    Chen, Chih-Hao; Kuo, Chang-Yi; Wang, Yan-Jie; Chen, Jyh-Ping

    2016-01-01

    Glucosamine (GlcN) fulfills many of the requirements as an ideal component in scaffolds used in cartilage tissue engineering. The incorporation of GlcN in a gelatin/hyaluronic acid (GH) cryogel scaffold could provide biological cues in maintaining the phenotype of chondrocytes. Nonetheless, substituting gelatin with GlcN may also decrease the crosslinking density and modulate the mechanical properties of the cryogel scaffold, which may be beneficial as physical cues for chondrocytes in the scaffold. Thus, we prepared cryogel scaffolds containing 9% GlcN (GH-GlcN9) and 16% GlcN (GH-GlcN16) by carbodiimide-mediated crosslinking reactions at −16 °C. The crosslinking density and the mechanical properties of the cryogel matrix could be tuned by adjusting the content of GlcN used during cryogel preparation. In general, incorporation of GlcN did not influence scaffold pore size and ultimate compressive strain but increased porosity. The GH-GlcN16 cryogel showed the highest swelling ratio and degradation rate in hyaluronidase and collagenase solutions. On the contrary, the Young’s modulus, storage modulus, ultimate compressive stress, energy dissipation level, and rate of stress relaxation decreased by increasing the GlcN content in the cryogel. The release of GlcN from the scaffolds in the culture medium of chondrocytes could be sustained for 21 days for GH-GlcN16 in contrast to only 7 days for GH-GlcN9. In vitro cell culture experiments using rabbit articular chondrocytes revealed that GlcN incorporation affected cell proliferation, morphology, and maintenance of chondrogenic phenotype. Overall, GH-GlcN16 showed the best performance in maintaining chondrogenic phenotype with reduced cell proliferation rate but enhanced glycosaminoglycans (GAGs) and type II collagen (COL II) secretion. Quantitative real-time polymerase chain reaction also showed time-dependent up-regulation of cartilage-specific marker genes (COL II, aggrecan and Sox9) for GH-GlcN16. Implantation of

  6. Multifunctional poly(alkyl methacrylate) films for dental care.

    PubMed

    Nielsen, Birthe V; Nevell, Thomas G; Barbu, Eugen; Smith, James R; Rees, Gareth D; Tsibouklis, John

    2011-02-01

    Towards the evaluation of non-permanent dental coatings for their capacity to impart dental-care benefits, thin films of a homologous series of comb-like poly(alkyl methacrylate)s (ethyl to octadecyl) have been deposited, from aqueous latex formulations, onto dentally relevant substrates. AFM studies have shown that the thickness (40-300 nm) and surface roughness (8-12 nm) of coherent polymer films are influenced by the degree of polymerization and by the length of the pendant chain. Of the polymers under consideration, poly(butyl methacrylate) formed a close-packed film that conferred to dental substrates a high degree of inhibition to acid-mediated erosion (about 27%), as evaluated by released-phosphate determinations. The potential utility of the coatings to act as anti-sensitivity barriers has been evaluated by determining the hydraulic conductance of coated bovine-dentine substrates; single treatments of dentine discs with poly(butyl methacrylate) or with poly(ethyl methacrylate) effected mean respective reductions in fluid flow of about 23% with respect to water-treated controls; repeated applications of the poly(butyl methacrylate) latex led to mean reductions in fluid flow of about 80%. Chromometric measurements have shown that pellicle-coated hydroxyapatite discs treated with poly(butyl methacrylate), poly(hexyl methacrylate) or poly(lauryl methacrylate) exhibit significant resistance to staining by food chromogens.

  7. Aluminum surface modification with fluoroalkyl methacrylate-based copolymers to attain superhydrophobic properties

    NASA Astrophysics Data System (ADS)

    Bryuzgin, Evgeny V.; Klimov, Victor V.; Repin, Sergey A.; Navrotskiy, Alexander V.; Novakov, Ivan A.

    2017-10-01

    We propose a novel approach to create a superhydrophobic coating on an aluminum surface by attaching random copolymers that are based on glycidyl methacrylate and a number of fluoroalkyl methacrylates that contain 3-7 fluorine atoms in their monomer units. To texture the aluminum surface, short-term etching with hydrochloric acid solutions was used. The coatings that are based on glycidyl methacrylate and fluoroalkyl methacrylate copolymers maintain superhydrophobic properties for longer than 40 h under saturated vapor conditions.

  8. Radiation-induced synthesis and swelling properties of p(2-hydroxyethyl methacrylate/itaconic acid/oligo (ethylene glycol) acrylate) terpolymeric hydrogels

    NASA Astrophysics Data System (ADS)

    Micic, M.; Stamenic, D.; Suljovrujic, E.

    2012-09-01

    Since it is presumed that by incorporation of pH-responsive (IA) and temperature-responsive (OEGA) co-monomers, it is possible to prepare P(HEMA/IA/OEGA) hydrogels with dual (pH and thermo) responsiveness, the main purpose of our study is to investigate the influence of different mole fractions of IA and especially OEGA on the diversity of the swelling properties of the obtained hydrogels. For that reason, a series of terpolymeric hydrogels with different mole ratios of 2-hydroxyethyl methacrylate (HEMA), itaconic acid (IA) and oligo(ethylene glycol) acrylates (OEGA) was synthesised by gamma radiation. The obtained hydrogels were characterised by swelling studies in the wide pH (2.2-9.0) and temperature range (20-70 °C), confirming dual (pH and thermo) responsiveness and a large variation in the swelling capability. It was observed that the equilibrium swelling of P(HEMA/IA/OEGA) hydrogels, for a constant amount of IA, increased progressively with an increase in OEGA share. On the other hand, the dissociation of carboxyl groups from IA occurs at pH>4; therefore, small mole fractions of IA render good pH sensitivity and a large increase in the swelling capacity of these hydrogels at higher pH values. Additional characterisation of structure and properties was conducted by Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM) and mechanical measurements, confirming that the inherent properties of P(HEMA/IA/OEGA) hydrogels can be significantly tuned by variation in their composition. According to all presented, it seems that the obtained hydrogels can be a beneficial synergetic combination for controlled delivery of bioactive molecules such as drugs, peptides, proteins, etc.

  9. Utilization of theoretical studies of the imprinting ratio to guide experimental research into the molecular imprinted polymers formed using enrofloxacin and methacrylic acid.

    PubMed

    Liu, Junbo; Dai, Zhengqiang; Li, Bo; Tang, Shanshan; Jin, Ruifa

    2014-10-01

    Computational approaches have been suggested as rational and fast methods for optimizing imprinting ratios. The B3LYP/6-31 g(d,p) level was applied to simulate the self-assembled system of molecularly imprinted polymers (MIPs) formed by enrofloxacin (ENRO) and methacrylic acid (MAA). Geometry optimization, the bonding situation, and the binding energies involved were studied to determine the impact of varying the imprinting ratio on the recognition characteristics. These theoretical results showed that the compound with an ENRO:MAA ratio of 1:7 had the lowest binding energy and the most stable structure. MIPs with different imprinting ratios of ENRO to MAA were then prepared in order to study the binding capacities of the polymers experimentally. The experimental and theoretically calculated results for these polymers were found to be consistent with each other. In dynamic adsorption experiments on the MIPs, the adsorption reaction was observed to reach a balanced state after 120 min. Analysis of the Scatchard plot revealed that the dissociation constant (K d) and the apparent maximum binding capacity (Q max) of MIPs with high-affinity sites were 451.67 mg/L and 42.23 mg/g, respectively, whereas the dissociation constant and apparent maximum binding capacity of MIPs with low-affinity sites were 883.39 mg/L and 73.15 mg/g, respectively. The quantity of ENRO adsorbed onto the MIPs was considerably higher than the quantities of ciprofloxacin (CIP) and ofloxacin (OFL) adsorbed, indicating that these MIPs have a much higher specific absorption capacity than the corresponding non-imprinted polymers.

  10. Development of molecularly imprinted poly(methacrylic acid)/silica for clean-up and selective extraction of cholesterol in milk prior to analysis by HPLC-UV.

    PubMed

    Clausen, D N; Visentainer, J V; Tarley, C R T

    2014-10-07

    In the present paper the assessment of a novel molecularly imprinted polymer, poly(methacrylic acid)/silica, for clean-up and selective extraction of cholesterol in milk samples is described. The relative selectivity coefficient (k) values for cholesterol/5-α-cholestane and cholesterol/7-dehydrocholesterol systems were found to be 5.08 and 6.08, respectively, thus attesting the selectivity of the MIP for cholesterol under competitive adsorption with structurally analogous steroid compounds. The milk analysis was initially based on saponification followed by liquid-liquid extraction with n-hexane. Then, the protocol of molecularly imprinted solid phase extraction (MISPE) was carried out by loading the milk hexanic extract through 200 mg of MIP or NIP (non-imprinted polymer) packed into SPE cartridges at a flow rate of 0.6 mL min(-1). The washing step was performed by using n-hexane followed by further elution with ethanol and HPLC-UV analysis at 208 nm. From the breakthrough curve the maximum adsorption capacity of the MIP towards cholesterol was found to be 29.51 mg g(-1). The precision of the MISPE protocol was assessed as intra- and inter-days yielding RSD (relative standard deviations) lower than 4.10%. Cleaner HPLC chromatograms were obtained for milk samples submitted to the MISPE protocol in comparison to the solid phase extraction using the NIP or modified octadecyl silica (C18). Recoveries varying from 96.6 up to 102.2% for milk samples spiked with cholesterol were achieved, thus ensuring the accuracy of the proposed method.

  11. Improved wet bonding of methyl methacrylate-tri-n-butylborane resin to dentin etched with ten percent phosphoric acid in the presence of ferric ions.

    PubMed

    Iwasaki, Yasuhiko; Toida, Tetsuya; Nakabayashi, Nobuo

    2004-03-01

    The objective of this study was to determine the influence of dissolved dentinal substances in demineralized dentin on the hybridization of resin for bonding to dentin. It was hypothesized that these substances, including polyelectrolytes, significantly change the substrates, which could then be assessed by the addition of Na(+), Ca(2+), or Fe(3+) in 10% phosphoric acid. Bovine dentin specimens were etched for 10 s with a solution of 10% phosphoric acid (control) or of 22.0 mM dissolved sodium chloride (10P-Na), calcium chloride (10P-Ca), or ferric chloride (10P-Fe). The specimens were then rinsed, blot-dried, and primed three times with 5% 4-methacryloyloxyethyl trimellitate anhydride in acetone for 60 s. Methyl methacrylate-tri-n-butylborane resin was then applied. The tensile bond strength of each of the dumbbell-shaped specimens was then measured. The fractured surfaces and modified cross-sections were examined by scanning electron microscopy. The cross-sections were soaked in 6N HCl for 10 s and then in 1% sodium hypochlorite for 30 min to determine the resin content in the hybridized specimens. Shrinkage of the demineralized dentins upon drying was assessed by atomic force microscopy. The tensile bond strengths were 10.8 +/- 4.5 (control), 15.0 +/- 7.0 (10P-Na), 19.3 +/- 5.5 (10P-Ca), and 27.8 +/- 8.1 (10P-Fe) MPa. The atomic force microscopy studies showed that Fe(3+) minimized the shrinkage by drying for 10 s but Ca(2+) and Na(+) did not decrease the shrinkage the same as the control. The results support the hypothesis that the monomer permeability of wet demineralized dentin is effectively improved by dissolving ferric ions in the phosphoric acid, resulting in a greater bond strength and higher resin content in the hybridized dentin. The dissolved dentinal substances, including the polyelectrolytes, had a significant influence on the characteristics of the demineralized dentin, changing the degree of hybridization and bonding.

  12. Properties of gelatin film from horse mackerel (Trachurus japonicus) scale.

    PubMed

    Le, Thuy; Maki, Hiroki; Takahashi, Kigen; Okazaki, Emiko; Osako, Kazufumi

    2015-04-01

    Optimal conditions for extracting gelatin and preparing gelatin film from horse mackerel scale, such as extraction temperature and time, as well as the protein concentration of film-forming solutions were investigated. Yields of extracted gelatin at 70 °C, 80 °C, and 90 °C for 15 min to 3 h were 1.08% to 3.45%, depending on the extraction conditions. Among the various extraction times and temperatures, the film from gelatin extracted at 70 °C for 1 h showed the highest tensile strength and elongation at break. Horse mackerel scale gelatin film showed the greatly low water vapor permeability (WVP) compared with mammalian or fish gelatin films, maybe due to its containing a slightly higher level of hydrophobic amino acids (total 653 residues per 1000 residues) than that of mammalian, cold-water fish and warm-water fish gelatins. Gelatin films from different preparation conditions showed excellent UV barrier properties at wavelength of 200 nm, although the films were transparent at visible wavelength. As a consequence, it can be suggested that gelatin film from horse mackerel scale extracted at 70 °C for 1 h can be applied to food packaging material due to its lowest WVP value and excellent UV barrier properties.

  13. The role of poly(methacrylic acid) conformation on dispersion behavior of nano TiO2 powder

    NASA Astrophysics Data System (ADS)

    Singh, Bimal P.; Nayak, Sasmita; Samal, Samata; Bhattacharjee, Sarama; Besra, Laxmidhar

    2012-02-01

    To exploit the advantages of nanoparticles for various applications, controlling the dispersion and agglomeration is of paramount importance. Agglomeration and dispersion behavior of titanium dioxide (TiO2) nanoparticles was investigated using electrokinetic and surface chemical properties. Nanoparticles are generally stabilized by the adsorption of a dispersant (polyelectrolyte) layer around the particle surface and in this connection ammonium salt of polymethacrylic acid (Darvan C) was used as dispersant to stabilize the suspension. The dosages of polyelectrolyte were optimized to get best dispersion stability by techniques namely particle charge detector (13.75 mg/g) and adsorption (14.57 mg/g). The surface charge of TiO2 particles changed significantly in presence of dispersant Darvan C and isoelectric point (iep) shifted significantly towards lower pH from 5.99 to 3.37. The shift in iep has been quantified in terms of free energy of interaction between the surface sites of TiO2 and the adsorbing dispersant Darvan C. Free energies of adsorption were calculated by electrokinetic data (-9.8 RT unit) and adsorption isotherms (-10.56 RT unit), which corroborated well. The adsorption isotherms are of typical Langmuir type and employed for calculation of free energy. The results indicated that adsorption occurs mainly through electrostatic interactions between the dispersant molecule and the TiO2 surface apart from hydrophobic interactions.

  14. Molecular spectroscopic analyses of gelatin.

    PubMed

    Ibrahim, Medhat; Mahmoud, Abdel Aziz; Osman, Osama; Abd el-Aal, Mohamed; Eid, May

    2011-10-15

    The molecular structure of gelatin was studied using Fourier transform infrared spectroscopy FTIR. The spectrum is subjected to deconvolution in order to elucidate the constituents of the molecular structure. B3LYP/6-31g** was used to study 13 amino acids then the scaled spectrum was compared to those of protein in order to describe the contribution of each amino acid into protein structure. A special interest was paid to the NH and C=O region. The reactivity of each amino acid was studied in terms of some important physical parameters like total dipole moment and HOMO/LUMO which describe the interaction of amino acid with their surrounding molecules. Results indicated that B3LYP/6-31g** model is a suitable and precise method for studying molecular structure of protein. Copyright © 2011 Elsevier B.V. All rights reserved.

  15. Collagen and gelatin.

    PubMed

    Liu, Dasong; Nikoo, Mehdi; Boran, Gökhan; Zhou, Peng; Regenstein, Joe M

    2015-01-01

    Collagen and gelatin have been widely used in the food, pharmaceutical, and cosmetic industries due to their excellent biocompatibility, easy biodegradability, and weak antigenicity. Fish collagen and gelatin are of renewed interest, owing to the safety and religious concerns of their mammalian counterparts. The structure of collagen has been studied using various modern technologies, and interpretation of the raw data should be done with caution. The structure of collagen may vary with sources and seasons, which may affect its applications and optimal extraction conditions. Numerous studies have investigated the bioactivities and biological effects of collagen, gelatin, and their hydrolysis peptides, using both in vitro and in vivo assay models. In addition to their established nutritional value as a protein source, collagen and collagen-derived products may exert various potential biological activities on cells in the extracellular matrix through the corresponding food-derived peptides after ingestion, and this might justify their applications in dietary supplements and pharmaceutical preparations. Moreover, an increasing number of novel applications have been found for collagen and gelatin. Therefore, this review covers the current understanding of the structure, bioactivities, and biological effects of collagen, gelatin, and gelatin hydrolysates as well as their most recent applications.

  16. Gelatin-loaded p(HEMA-GMA) cryogel for high-capacity immobilization of horseradish peroxidase.

    PubMed

    Soomro, Rabel; Perçin, Işık; Memon, Najma; Iqbal Bhanger, Muhammad; Denizli, Adil

    2016-11-01

    Poly(2-hydroxyethyl methacrylate-glycidyl methacrylate) [p(HEMA-GMA)] cryogel discs were prepared under sub-zero temperatures. Gelatin was attached covalently on the p(HEMA-GMA) cryogel discs and reversible immobilization of horseradish peroxidase (HRP) was performed. The p(HEMA-GMA) cryogel discs were characterized by swelling tests, scanning electron microscopy, and surface area measurements. HRP immobilization capacity of p(HEMA-GMA)/gelatin cryogel discs was 24.8 mg/g. Removal of phenol from aqueous solutions was performed using HRP immobilized p(HEMA-GMA)/gelatin cryogel. It was observed that within 2 h of contact time, the percentage of phenol removal reaches up to 91% in the presence of H2O2.

  17. Thermally controlled protein release from gelatin dextran hydrogels

    NASA Astrophysics Data System (ADS)

    Aso, Y.; Yoshioka, S.; Nakai, Y.; Kojima, S.

    1999-06-01

    Biodegradable hydrogels in which drug release was controlled by sol-gel transition were prepared. Gelatin was used as a component because it exhibits sol-gel transition in response to temperature changes. Glycidyl methacrylated (GMA) dextran was crosslinked by low dose γ-irradiation in the presence of gelatin and the model drugs, β-galactosidase ( β-GA), bovine serum albumin (BSA) or 5-fluorouracil (5-FU). The enzyme activity of β-GA remained greater than 95% after irradiation. Temperature-responsive release of β-GA and BSA resulted from the sol-gel transition of gelatin. Sol-gel transition was confirmed by the temperature dependence of the spin-spin relaxation time of the gel polymer protons. The protein release rate was affected by both the degree of GMA substitution and the gelatin concentration. Desired release rate could be achieved by adjusting these factors. The release rate of 5-FU was not affected by the sol-gel transition of gelatin.

  18. Using glucosamine to improve the properties of photocrosslinked gelatin scaffolds.

    PubMed

    Suo, Hairui; Xu, Kedi; Zheng, Xiaoxiang

    2015-02-01

    The use of hydrogel-based cell transport scaffolds holds great promise in regenerative medicine, such as treating osteoarthritis. Gelatin and glucosamine are the ideal materials to be used in the hydrogel scaffolds for cartilage regeneration for they could act as compositions of cartilage. To overcome the weak strength of traditional gelatin hydrogels and down-regulate cell toxicity of glucosamine, gelatin and glucosamine molecules were grafted with acrylate groups and covalently crosslinked under photo-radiation to form hydrogels. Hydrogels with tuning physiochemical properties were produced according to different proportions of methacrylate gelatin (GelMA) and N-acryloyl glucosamine (AGA). The process of photocrosslinking was elaborated, and the hypothesis of increasing AGA concentration leading to higher strength of hydrogels was corroborated by testing rheological property and scanning micro-morphological features. A serial of properties, including smaller swelling ratio, lower gelatin dissolution and slower degradation of GelMA/AGA hydrogels with higher AGA concentration further proved our hypothesis. Moreover, AGA molecules showed less cytotoxicity than unmodified glucosamine molecules and the incorporation of AGA molecules in GelMA/AGA hydrogels upregulated cell adhesion and spreading on the hydrogel surface. All of these results indicated that addition of AGA molecules could significantly alter the physiochemical properties of GelMA/AGA hydrogels, which may have broad application prospects in the future.

  19. Thermoforming polymethyl methacrylate.

    PubMed

    Jagger, R G; Okdeh, A

    1995-11-01

    This study characterized a range of commercially available polymethyl methacrylate sheets with respect to molecular weight, residual monomer content, and glass transition temperature and then developed a thermoforming procedure that produced visually satisfactory thermoformed polymethyl methacrylate specimens. Molecular weight values of Perspex material were considerably greater than those of the other materials. All materials but Diakon had residual monomer concentrations of less than 1% and glass transition temperature values greater than 100 degrees C. Perspex material was selected for further investigation. It was necessary to preheat Perspex sheets in an oven at 160 degrees C for at least 30 minutes before heating and forming on the thermoforming apparatus to obtain acceptable specimens.

  20. Cellulose acetate/poly lactic acid coaxial wet-electrospun scaffold containing citalopram-loaded gelatin nanocarriers for neural tissue engineering applications.

    PubMed

    Naseri-Nosar, Mahdi; Salehi, Majid; Hojjati-Emami, Shahriar

    2017-10-01

    The current study aimed to develop a biodegradable three-dimensional drug-loaded scaffold with the core-shell structured fibrils using coaxial wet-electrospinning for neural tissue engineering application. Poly lactic acid was wet-electrospun as the core, whereas cellulose acetate was fabricated into the fibril's shell. The scaffold then was coated with the citalopram-loaded gelatin nanocarriers (CGNs) produced by nanoprecipitation method. Scanning electron microscope observation revealed that the fibrils formed a nonwoven structure with the average diameter of ∼950nm. The particle size measurement by a dynamic light scattering device showed an average diameter of ∼200nm. The porosity measurement via the liquid displacement method showed that the scaffold could not meet the accepted ideal porosity percentage of above 80%, and the measured porosity percentage was ∼60%. The contact angle measurement displayed that the CGN coating made the scaffold highly hydrophilic with a zero degree contact angle. In vitro degradation study in the phosphate buffered saline revealed that the weight of the uncoated scaffold remained relatively constant. However, the CGNs-coated scaffold showed ∼45% weight-loss percentage after 40days. Cytocompatibility evaluation using rat Schwann cells demonstrated that the CGNs-coated scaffold possessed higher cell viability than the uncoated scaffold. Finally, the scaffold was developed into a nerve guidance conduit and surgically implanted in the sciatic nerve defect in Wistar rats. The results of the sciatic functional index, hot plate latency and weight-loss percentage of the wet gastrocnemius muscle, demonstrated that the citalopram-containing scaffold could ameliorate the functional recovery of the sciatic nerve-injured animals which makes it a potential candidate for the neural tissue engineering applications. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. In vitro and in vivo efficacy of doxorubicin loaded biodegradable semi-interpenetrating hydrogel implants of poly (acrylic acid)/gelatin for post surgical tumor treatment.

    PubMed

    Jaiswal, Maneesh; Naz, Farhat; Dinda, Amit K; Koul, Veena

    2013-08-01

    The paper describes the preparation and evaluation of doxorubicin loaded semi-interpenetrating polymeric hydrogel network of polyacrylic acid (PAc) and gelatin (G). Post surgical antitumor efficacy and biodistribution of doxorubicin from the implanted degradable hydrogels was investigated on Ehrlich's ascites tumor model using albino mice. Polycaprolactone diacrylate (PCL-DAr) was employed as a crosslinking agent for PAc chains whereas G was kept free. The effect of crosslinking concentration on various physico-chemical properties such as thermal behavior, swelling, degradation behavior, drug release and polymer-polymer interactions was investigated by various physico-chemical tools. Semi-interpenetrating polymeric networks (IPNs) with 0.2 mol% crosslinking concentration showed degradation within 20 days in phosphate buffer (pH 6.5). To determine the in vivo anticancer efficacy, placebo and drug laden cylindrical implants (65 ± 5 µg/implant of 10 mg) were implanted in tumor cavity post tumor excision. After predetermined time intervals (day 7, 11, 14, 20 and 25), drug biodistribution was assessed in tumor, tumor periphery, residual hydrogel and all vital organs i.e. liver, spleen, kidney, heart, lung and blood (spectrofluorimetrically). The drug distribution study showed the concentration of drug in the tumor, tumor periphery and residual hydrogel decreased with increasing time; on the 7th day, drug concentration was highest while, on the 25th day, it was negligible; however, insignificant quantities of the drug was found in vital organs. Histological examination revealed no sign of tumor recurrence until the 25th day with 100% necrosis and slight inflammation in treated the group. In vivo results established that these biodegradable implants can be utilized as post surgical therapy for solid tumors.

  2. Sciatic nerve regeneration by transplantation of Schwann cells via erythropoietin controlled-releasing polylactic acid/multiwalled carbon nanotubes/gelatin nanofibrils neural guidance conduit.

    PubMed

    Salehi, Majid; Naseri-Nosar, Mahdi; Ebrahimi-Barough, Somayeh; Nourani, Mohammdreza; Khojasteh, Arash; Hamidieh, Amir-Ali; Amani, Amir; Farzamfar, Saeed; Ai, Jafar

    2017-07-04

    The current study aimed to enhance the efficacy of peripheral nerve regeneration using an electrically conductive biodegradable porous neural guidance conduit for transplantation of allogeneic Schwann cells (SCs). The conduit was produced from polylactic acid (PLA), multiwalled carbon nanotubes (MWCNTs), and gelatin nanofibrils (GNFs) coated with the recombinant human erythropoietin-loaded chitosan nanoparticles (rhEpo-CNPs). The PLA/MWCNTs/GNFs/rhEpo-CNPs conduit had the porosity of 85.78 ± 0.70%, the contact angle of 77.65 ± 1.91° and the ultimate tensile strength and compressive modulus of 5.51 ± 0.13 MPa and 2.66 ± 0.34 MPa, respectively. The conduit showed the electrical conductivity of 0.32 S cm(-1) and lost about 11% of its weight after 60 days in normal saline. The produced conduit was able to release the rhEpo for at least 2 weeks and exhibited favorable cytocompatibility towards SCs. For functional analysis, the conduit was seeded with 1.5 × 10(4) SCs and implanted into a 10 mm sciatic nerve defect of Wistar rat. After 14 weeks, the results of sciatic functional index, hot plate latency, compound muscle action potential amplitude, weight-loss percentage of wet gastrocnemius muscle and Histopathological examination using hematoxylin-eosin and Luxol fast blue staining demonstrated that the produced conduit had comparable nerve regeneration to the autograft, as the gold standard to bridge the nerve gaps. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2017. © 2017 Wiley Periodicals, Inc.

  3. Platelet-rich plasma encapsulation in hyaluronic acid/gelatin-BCP hydrogel for growth factor delivery in BCP sponge scaffold for bone regeneration.

    PubMed

    Son, So-Ra; Sarkar, Swapan Kumar; Nguyen-Thuy, Ba Linh; Padalhin, Andrew R; Kim, Bo Ram; Jung, Hae Il; Lee, Byong-Taek

    2015-02-01

    Microporous calcium phosphate based synthetic bone substitutes are used for bone defect healing. Different growth factor loading has been investigated for enhanced bone regeneration. The platelet is a cellular component of blood which naturally contains a pool of necessary growth factors that mediate initiation, continuation, and completion of cellular mechanism of healing. In this work, we have investigated the encapsulation and immobilization of platelet-rich plasma (PRP) with natural polymers like hyaluronic acid (HA) and gelatin (Gel) and loading them in a biphasic calcium phosphate (BCP) scaffold, for a synthetic-allologous hybrid scaffold. Effect of PRP addition in small doses was evaluated for osteogenic potential in vitro and in vivo. BCP (10%) mixed HA-Gel hydrogel with or without PRP, was loaded into a BCP sponge scaffold. We investigated the hydrogel-induced improvement in mechanical property and PRP-mediated enhancement in biocompatibility. In vitro studies for cytotoxicity, cell attachment, and proliferation were carried out using MC3T3-E1 pre-osteoblast cells. In in vitro studies, the cell count, cell proliferation, and cell survival were higher in the scaffold with PRP loading than without PRP. However, in the in vivo studies using a rat model, the PRP scaffold was not superior to the scaffold without PRP. This discrepancy was investigated in terms of the interaction of PRP in the in vivo environment. © The Author(s) 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

  4. The lower alkyl methacrylates: Genotoxic profile of non-carcinogenic compounds.

    PubMed

    Albertini, Richard J

    2017-03-01

    All of the lower alkyl methacrylates are high production chemicals with potential for human exposure. The genotoxicity of seven mono-functional alkyl esters of methacrylic acid, i.e. methyl methacrylate, ethyl methacrylate, hydroxyethyl methacrylate, n-, i- and t-butyl methacrylate and 2 ethyl hexyl methacrylate, as well as methacrylic acid itself, the acyl component common to all, is reviewed and compared with the lack of carcinogenicity of methyl methacrylate, the representative member of the series so evaluated. Also reviewed are the similarity of structure, chemical and biological reactivity, metabolism and common metabolic products of this group of compounds which allows a category approach for assessing genotoxicity. As a class, the lower alkyl methacrylates are universally negative for gene mutations in prokaryotes but do exhibit high dose clastogenicity in mammalian cells in vitro. There is no convincing evidence that these compounds induce genotoxic effects in vivo in either sub-mammalian or mammalian species. This dichotomy of effects can be explained by the potential genotoxic intermediates generated in vitro. This genotoxic profile of the lower alkyl methacrylates is consistent with the lack of carcinogenicity of methyl methacrylate.

  5. Preparation of high efficiency and low carry-over immobilized enzymatic reactor with methacrylic acid-silica hybrid monolith as matrix for on-line protein digestion.

    PubMed

    Yuan, Huiming; Zhang, Lihua; Zhang, Yukui

    2014-12-05

    In this work, a novel kind of organic-silica hybrid monolith based immobilized enzymatic reactor (IMER) was developed. The monolithic support was prepared by a single step "one-pot" strategy via the polycondensation of tetramethoxysilane and vinyltrimethoxysilane and in situ copolymerization of methacrylic acid and vinyl group on the precondensed siloxanes with ammonium persulfate as the thermal initiator. Subsequently, the monolith was activated by N-(3-dimethylaminopropyl) - N'-ethylcarbodiimide (EDC) and N-hydroxysuccinimide (NHS), followed by the modification of branched polyethylenimine (PEI) to improve the hydrophilicity. Finally, after activated by EDC and NHS, trypsin was covalently immobilized onto the monolithic support. The performance of such a microreactor was evaluated by the in sequence digestion of bovine serum albumin (BSA) and myoglobin, followed by MALDI-TOF-MS analysis. Compared to those obtained by traditional in-solution digestion, not only higher sequence coverages for BSA (74±1.4% vs. 59.5±2.7%, n=6) and myoglobin (93±3% vs. 81±4.5%, n=6) were obtained, but also the digestion time was shortened from 24h to 2.5 min, demonstrating the high digestion efficiency of such an IMER. The carry-over of these two proteins on the IMER was investigated, and peptides from BSA could not be found in mass spectrum of myoglobin digests, attributed to the good hydrophilicity of our developed monolithic support. Moreover, the dynamic concentration range for protein digestion was proved to be four orders of magnitude, and the IMER could endure at least 7-day consecutive usage. Furthermore, such an IMER was coupled with nano-RPLC-ESI/MS/MS for the analysis of extracted proteins from Escherichia coli. Compared to formerly reported silica hybrid monolith based IMER and the traditional in-solution counterpart, by our developed IMER, although the identified protein number was similar, the identified distinct peptide number was improved by 7% and 25% respectively

  6. Fish gelatin: Material properties and applications

    USDA-ARS?s Scientific Manuscript database

    The main difference between fish gelatin and mammalian gelatin is fish gelatin’s lower gelation temperature. This property limits the use of fish gelatin in applications that currently utilize mammalian gelatin. However, fish gelatin remains an attractive alterative to mammalian gelatin due to relig...

  7. Impact of electron beam irradiation on fish gelatin film properties.

    PubMed

    Benbettaïeb, Nasreddine; Karbowiak, Thomas; Brachais, Claire-Hélène; Debeaufort, Frédéric

    2016-03-15

    The objective of this work was to display the effect of electron beam accelerator doses on properties of plasticized fish gelatin film. Electron spin resonance indicates free radical formation during irradiation, which might induce intermolecular cross-linking. Tensile strength for gelatin film significantly increases after irradiation (improved by 30% for 60 kGy). The vapour permeability is weakly affected by irradiation. Surface tension and its polar component increase significantly and are in accordance with the increase of wettability. So, irradiation may change the orientation of polar groups of gelatin at the film surface and crosslink the hydrophobic amino acids. No modification of the crystallinity of the film is observed. These findings suggest that if structure changes, it only occurs in the amorphous phase of the gelatin matrix. It is also observed that irradiation enhances the thermal stability of the gelatin film, by increasing the glass transition temperature and the degradation temperature.

  8. Validation of a reverse-phase high-performance liquid chromatography method for the determination of amino acids in gelatins by application of 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate reagent.

    PubMed

    Azilawati, M I; Hashim, D M; Jamilah, B; Amin, I

    2014-08-01

    In-house method validation was conducted to determine amino acid composition in gelatin by a pre-column derivatization procedure with the 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate reagent. The analytical parameters revealed that the validated method was capable of selectively performing a good chromatographic separation for 18 amino acids in less than 40 min; the overall detection and quantitation limit for amino acids fell into ranges of 5.68-12.48 and 36.0-39.0 pmol/μl, respectively; the matrix effect was not observed, and the linearity range was 37.5-1000 pmol/μl. The accuracy (precision and recovery) analyses of the method were conducted under repeatable conditions on different days in random order. Method precision revealed by HorRat values was significantly less than 2, except for histidine with a precision of 2.19, and the method recoveries had a range of 80-115% except for alanine which was recovered at 79.4%. The findings were reproducible and accurately defined, and the method was found to be suited to routine analysis of amino acid composition in gelatin-based ingredients. Copyright © 2014 Elsevier B.V. All rights reserved.

  9. Gelatin capsule in stomach (image)

    MedlinePlus

    ... detect the presence of intestinal parasites. A weighted gelatin capsule attached to a string is swallowed and left in place. After about 4 hours, the gelatin capsule is pulled out of the stomach by ...

  10. Biodegradable Films Based on Gelatin Extracted from Chrome Leather Scrap.

    PubMed

    Dang, Xugang; Shan, Zhihua; Chen, Hui

    2017-09-19

    A biodegradable film based on gelatin extracted from chrome leather scrap was studied in this paper. According to the results of a variety of characterization, the extracted gelatin contains 13 kinds of amino acid; the chrome content is 30mg/kg, mineral and salt content are both at low levels and the nitrogen content is 43.84%. Its molecular weight has been measured at about 6.5kDa ∼26.6kDa, and the average particle distribution appears to be 125nm with a narrow distribution. When the extracted gelatin was modified with the β-cyclodextrin to prepare the biodegradable films, the β-cyclodextrin and gelatin blends can build up perfect compatibility and film-forming properties. Comparing to the gelatin film without β-cyclodextrin, the viscosity, biodegradability, thermal stability and physical properties of the β-cyclodextrin and gelatin blends in the present research were significantly increased, especially when the ratio of β-cyclodextrin to gelatin was 1:2, the biodegradation rates reached 81%, elongation at break 15.74% and the tensile strength 122.34MPa. The blends show perfect swelling properties and overcome the rapid solubility drawback of extracted gelatin. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. Preparation and Characterization of Gelatin Nanofibers Containing Silver Nanoparticles

    PubMed Central

    Jeong, Lim; Park, Won Ho

    2014-01-01

    Ag nanoparticles (NPs) were synthesized in formic acid aqueous solutions through chemical reduction. Formic acid was used for a reducing agent of Ag precursor and solvent of gelatin. Silver acetate, silver tetrafluoroborate, silver nitrate, and silver phosphate were used as Ag precursors. Ag+ ions were reduced into Ag NPs by formic acid. The formation of Ag NPs was characterized by a UV-Vis spectrophotometer. Ag NPs were quickly generated within a few minutes in silver nitrate (AgNO3)/formic acid solution. As the water content of formic acid aqueous solution increased, more Ag NPs were generated, at a higher rate and with greater size. When gelatin was added to the AgNO3/formic acid solution, the Ag NPs were stabilized, resulting in smaller particles. Moreover, gelatin limits further aggregation of Ag NPs, which were effectively dispersed in solution. The amount of Ag NPs formed increased with increasing concentration of AgNO3 and aging time. Gelatin nanofibers containing Ag NPs were fabricated by electrospinning. The average diameters of gelatin nanofibers were 166.52 ± 32.72 nm, but these decreased with the addition of AgNO3. The average diameters of the Ag NPs in gelatin nanofibers ranged between 13 and 25 nm, which was confirmed by transmission electron microscopy (TEM). PMID:24758929

  12. 75 FR 770 - Acrylic acid-benzyl methacrylate-1-propanesulfonic acid, 2-methyl-2-[(1-oxo-2-propenyl)amino...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-06

    ... Nobel Surface Chemistry LLC submitted a petition to EPA under the Federal Food, Drug, and Cosmetic Act...- propanesulfonic acid, 2-methyl-2- -, monosodium salt copolymer on food or feed commodities. DATES: This regulation... producer, food manufacturer, or ] pesticide manufacturer. Potentially affected entities may include, but...

  13. Gelatin-chondroitin-6-sulfate-hyaluronic acid scaffold seeded with vascular endothelial growth factor 165 modified hair follicle stem cells as a three-dimensional skin substitute.

    PubMed

    Quan, Renfu; Zheng, Xuan; Xu, Shichao; Zhang, Liang; Yang, Disheng

    2014-10-20

    In the field of skin tissue engineering, gelatin-chondroitin-6-sulfate-hyaluronic acid (Gel-C6S-HA) stents are a suitable bio skin substitute. The purpose was to investigate the effect of genetically-modified hair follicle stem cells (HFSCs), combined with Gel-C6S-HA scaffolds, on the vascularization of tissue-engineered skin. Three-dimensional (3D) Gel-C6S-HA scaffolds were prepared by freeze-drying. Vascular endothelial growth factor (VEGF) 165 gene-modified rat HFSCs (rHFSCs) were inoculated into the scaffolds and cultured for 7 days. Two bilateral full-thickness skin defects were created on the back of 18 Sprague-Dawley rats. Rats were randomly divided into four groups: Group A, HFSCs transduced with VEGF165 seeded onto Gel-C6S-HA scaffolds; Group B, HFSCs transduced with empty vector seeded onto Gel-C6S-HA scaffolds; Group C, Gel-C6S-HA scaffold only; Group D, Vaseline gauze dressing. These compositions were implanted onto the defects and harvested at 7, 14 and 21 days. Wound healing was assessed and compared among groups according to hematoxylin-eosin staining, CD31 expression, alpha smooth muscle actin (α-SMA) and major histocompatibility complex class I (MHC-I) immunohistochemistry, and microvessel density (MVD) count, to evaluate the new blood vessels. SEM revealed the Gel-C6S-HA scaffold was spongy and 3D, with an average pore diameter of 133.23 ± 43.36 μm. Cells seeded on scaffolds showed good adherent growth after 7 days culture. No significant difference in rHFSC morphology, adherence and proliferative capacity was found before and after transfection (P >0.05). After 14 and 21 days, the highest rate of wound healing was observed in Group A (P <0.05). Histological and immunological examination showed that after 21 days, MVD also reached a maximum in Group A (P <0.05). Therefore, the number of new blood vessels formed within the skin substitutes was greatest in Group A, followed by Group B. In Group C, only trace amounts of mature subcutaneous

  14. AMPHOTERIC COLLOIDS : V. THE INFLUENCE OF THE VALENCY OF ANIONS UPON THE PHYSICAL PROPERTIES OF GELATIN.

    PubMed

    Loeb, J

    1919-05-20

    1. When we plot the values of osmotic pressure, swelling, and viscosity of gelatin solutions as ordinates over the pH as abscissae, practically identical curves are obtained for the effect of monobasic acids (HCl, HBr, HNO(3), and acetic acid) on these properties. 2. The curves obtained for the effect of H(2)SO(4) on gelatin are much lower than those obtained for the effect of monobasic acids, the ratio of maximal osmotic pressures of a 1 per cent solution of gelatin sulfate and gelatin bromide being about 3:8. The same ratio had been found for the ratio of maximal osmotic pressures of calcium and sodium gelatinate. 3. The curves representing the influence of other dibasic and tribasic acids, viz. oxalic, tartaric, succinic, citric, and phosphoric, upon gelatin are almost identical with those representing the effect of monobasic acids. 4. The facts mentioned under (2) and (3) permit us to decide between a purely chemical and a colloidal explanation of the influence of acids on the physical properties of gelatin. In the former case we should be able to prove, first, that twice as many molecules of HBr as of H(2)SO(4) combine with a given mass of gelatin; and, second, that the same number of molecules of phosphoric, citric, oxalic, tartaric, and succinic acids as of HNO(3) or HCl combine with the same mass of gelatin. It is shown in the present paper that this is actually the case. 5. It is shown that gelatin sulfate and gelatin bromide solutions of the same pH have practically the same conductivity. This disproves the assumption of colloid chemists that the difference in the effect of bromides and sulfates on the physical properties of gelatin is due to a different ionizing and hydratating effect of the two acids upon the protein molecule.

  15. Synthesis of mucoadhesive thiolated gelatin using a two-step reaction process.

    PubMed

    Duggan, Sarah; O'Donovan, Orla; Owens, Eleanor; Cummins, Wayne; Hughes, Helen

    2015-04-01

    Using a novel two-step approach, the thiolation of gelatin for mucoadhesive drug delivery has been achieved. The initial step involved the amination of native gelatin via an amine to carboxylic acid coupling reaction with ethylene diamine, followed by thiolation with Traut's reagent. The resulting thiolated product showed an increase in thiol content of up to 10-fold in comparison with control gelatin samples. Improved cohesion and mucoadhesion in comparison with unmodified and control gelatin samples was also observed. This reaction process was observed to be influenced by both the temperature and the pH of the amination reaction, affecting both amine content and product yield. Swelling ability, cohesion and mucoadhesion were all observed to be strongly dependent on the thiol content of the samples but also, importantly, the molecular weight (MW) of the gelatin used. Gelatin with a MW of 20-25 kDa proved to be optimal in creating this novel mucoadhesive gelatin material.

  16. Estimation of uncertainty from method validation data: Application to a reverse-phase high-performance liquid chromatography method for the determination of amino acids in gelatin using 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate reagent.

    PubMed

    Azilawati, M I; Dzulkifly, M H; Jamilah, B; Shuhaimi, M; Amin, I

    2016-09-10

    A detailed procedure for estimating uncertainty according to the Laboratory of Government Chemists/Valid Analytical Measurement (LGC/VAM) protocol for determination of 18 amino acids in gelatin is proposed. The expanded uncertainty was estimated using mainly the method validation data (precision and trueness). Other sources of uncertainties were contributed by components in standard preparation measurements. The method scope covered a single matrix (gelatin) under a wide range of analyte concentrations. The uncertainty of method precision, μ(P) was 0.0237-0.1128pmolμl(-1) in which hydroxyproline and histidine represented the lowest and highest values of uncertainties, respectively. Proline and phenylalanine represented the lowest and highest uncertainties value for method recovery, μ(R) that was estimated within 0.0064-0.0995pmolμl(-1). The uncertainties from other sources, μ(Std) were 0.0325, 0.0428 and 0.0413pmolμl(-1) that were contributed by hydroxyproline, other amino acids and cystine, respectively. Hydroxyproline and phenylalanine represented the lowest and highest values of expanded uncertainty, U(y) that were determined at 0.0949 and 0.2473pmolμl(-1), respectively. The data were accurately defined and fulfill the technical requirements of ISO 17025:2005. Copyright © 2016 Elsevier B.V. All rights reserved.

  17. Non-Covalent Photo-Patterning of Gelatin Matrices Using Caged Collagen Mimetic Peptides

    PubMed Central

    Li, Yang; Hoa San, Boi; L. Kessler, Julian; Hwan Kim, Jin; Xu, Qingguo; Hanes, Justin; Yu, Seungju Michael

    2015-01-01

    Advancements in photolithography have enabled us to spatially encode biochemical cues in biocompatible platforms such as synthetic hydrogels. Conventional patterning works through photo-activated chemical reactions on inert polymer networks. However, these techniques cannot be directly applied to protein hydrogels without chemically altering the protein scaffolds. To this end, we developed a non-covalent photo-patterning strategy for gelatin (denatured collagen) hydrogels utilizing a caged collagen mimetic peptide (caged CMP) which binds to gelatin strands through UV activated, triple helix hybridization. Here we present 2D and 3D photo-patterning of gelatin hydrogels enabled by the caged CMPs as well as creation of concentration gradients of CMPs. We show that photo-patterning of PEG-conjugated caged CMPs can be used to spatially control cell adhesion on gelatin films. CMP’s specificity for binding to gelatin allows patterning of almost any synthetic or natural gelatin-containing matrix, such as zymograms, gelatin-methacrylate hydrogels, and even a corneal tissue. Since the CMP is a chemically and biologically inert peptide which is proven to be an ideal carrier for bioactive molecules, our patterning method provides a radically new tool for immobilizing drugs to natural tissues and for functionalizing scaffolds for complex tissue formation. PMID:25476588

  18. Optimization of gelatin extraction from silver carp skin.

    PubMed

    Boran, G; Regenstein, J M

    2009-10-01

    Fish skins are a by-product of the fish processing industry that can be successfully processed into gelatin. This study was designed to optimize the extraction process to obtain the highest yield, gel strength, and viscosity for gelatin production from silver carp skin. A fractional factorial design (2 levels, resolution III, 2(9-5)) was chosen to screen 9 parameters to determine the most significant ones. Those found to be significant were optimized to determine the maximum value for 3 dependent variables mentioned above. The hydroxyproline content and hydroxyproline/protein ratio of the skin were 1.7% and 6.5%, respectively. The protein content of the skin was 26%. The hydroxyproline content of the gelatin for the sample giving the highest hydroxyproline/protein ratio was 10.9%. This sample was arbitrarily called pure gelatin and the purity of the remaining samples was between 71.8% and 97%. The highest protein and gelatin recovery was 78.1% and 98.8% of the total available, respectively. The latter, gelatin recovery, is proposed to be used instead of protein yield. Four variables were determined as significant in screening and these variables were studied by a central composite rotatable design (4-factor and 5-level with 6 central points) to model the system and response surface methodology was used for optimization. The optimum extraction conditions were 50 degrees C for the extraction temperature, 0.1 N HCl for the acid concentration, 45 min for the acid pretreatment time, and finally 4 : 1 (v/w) for the water/skin ratio. The predicted responses for these extraction conditions were 630 g gel strength, 6.3 cP viscosity, and 80.8% gelatin recovery. The data suggest that silver carp skin gelatin is similar to those of fish gelatins currently being exploited commercially.

  19. Dependence of copolymer composition, swelling history, and drug concentration on the loading of diltiazem hydrochloride (DIL.HCl) into poly[(N-isopropylacrylamide)-co-(methacrylic acid)] hydrogels and its release behaviour from hydrogel slabs.

    PubMed

    Sousa, Ricardo G; Prior-Cabanillas, Alberto; Quijada-Garrido, Isabel; Barrales-Rienda, José M

    2005-02-16

    The loading of an antihypertensive cationic drug, diltiazem hydrochloride (DIL.HCl), into poly(N-isopropylacrylamide) [P(N-iPAAm)], poly(methacrylic acid) [P(MAA)], and their poly[(N-isopropylacrylamide)-co-(methacrylic acid)] P[(N-iPAAm)-co-(MAA)] hydrogels as well as their release behaviour have been investigated. For this purpose, two series of hydrogels have been tested, one previously soaked under acidic pH (treated hydrogels) and the other from the synthesis and washed in deionized water (untreated hydrogels). For the drug loading, these two series of hydrogels have been soaked in drug solutions with different concentrations. DIL.HCl amounts loaded by the gels as well as swelling degrees as a function of both hydrogel composition and DL.HCl concentration in the loading solution have been analyzed. Due to the interactions among DIL.HCl and the MAA group, "untreated" enriched MAA copolymer hydrogels present the highest drug load and loading efficiency. A DIL.HCl concentration of 320 microm/mL has been employed to load copolymers for release experiments, because for this concentration, hydrogels reach relative high drug load with a still high efficiency of loading. Release has been tested in three media, namely, fresh water (Milli-Q grade, pH 7.0), 0.1 N hydrogen chloride (pH 1.2), and a phosphate buffer (pH 7.0). In general, release is lower in fresh water and acidic media than in phosphate buffer. To explain these results, the effect of temperature, medium, and composition on the pH and thermo sensitivity of the hydrogels as well as the diltiazem-polymer interactions have been taken into account.

  20. Gelatin-Graphene Nanocomposites with Ultralow Electrical Percolation Threshold.

    PubMed

    Nassira, Hoda; Sánchez-Ferrer, Antoni; Adamcik, Jozef; Handschin, Stephan; Mahdavi, Hossein; Taheri Qazvini, Nader; Mezzenga, Raffaele

    2016-08-01

    Gelatin-graphene conductive biopolymer nanocomposites (CPCs) with ultralow percolation threshold are designed by reducing in situ graphene oxide nanosheets with ascorbic acid and suppressing the aggregation of the graphene nanosheets. The resulting conductive nanocomposites show a record-low electrical percolation threshold of 3.3 × 10(-2) vol%, which arises from the homogeneous dispersion of the graphene nanosheets within the gelatin matrix.

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

    PubMed

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

    2009-08-01

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

  2. Gelatin controversies in food, pharmaceuticals, and personal care products: Authentication methods, current status, and future challenges.

    PubMed

    Ali, Eaqub; Sultana, Sharmin; Hamid, Sharifah Bee Abd; Hossain, Motalib; Yehya, Wageeh A; Kader, Abdul; Bhargava, Suresh K

    2016-12-29

    Gelatin is a highly purified animal protein of pig, cow, and fish origins and is extensively used in food, pharmaceuticals, and personal care products. However, the acceptability of gelatin products greatly depends on the animal sources of the gelatin. Porcine and bovine gelatins have attractive features but limited acceptance because of religious prohibitions and potential zoonotic threats, whereas fish gelatin is welcomed in all religions and cultures. Thus, source authentication is a must for gelatin products but it is greatly challenging due to the breakdown of both protein and DNA biomarkers in processed gelatins. Therefore, several methods have been proposed for gelatin identification, but a comprehensive and systematic document that includes all of the techniques does not exist. This up-to-date review addresses this research gap and presents, in an accessible format, the major gelatin source authentication techniques, which are primarily nucleic acid and protein based. Instead of presenting these methods in paragraph form which needs much attention in reading, the major methods are schematically depicted, and their comparative features are tabulated. Future technologies are forecasted, and challenges are outlined. Overall, this review paper has the merit to serve as a reference guide for the production and application of gelatin in academia and industry and will act as a platform for the development of improved methods for gelatin authentication.

  3. Wave propagation in ballistic gelatine.

    PubMed

    Naarayan, Srinivasan S; Subhash, Ghatu

    2017-04-01

    Wave propagation characteristics in long cylindrical specimens of ballistic gelatine have been investigated using a high speed digital camera and hyper elastic constitutive models. The induced transient deformation is modelled with strain rate dependent Mooney-Rivlin parameters which are determined by modelling the stress-strain response of gelatine at a range of strain rates. The varying velocity of wave propagation through the gelatine cylinder is derived as a function of prestress or stretch in the gelatine specimen. A finite element analysis is conducted using the above constitutive model by suitably defining the impulse imparted by the polymer bar into the gelatine specimen. The model results are found to capture the experimentally observed wave propagation characteristics in gelatine effectively. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. Contact dermatitis to methyl methacrylate.

    PubMed

    Kassis, V; Vedel, P; Darre, E

    1984-07-01

    2 cases of contact dermatitis to methyl methacrylate monomer are presented. The patients are nurses who mixed bone cement at orthopedic operations. During the procedure, they used 2 pairs of gloves (latex). Butyl rubber gloves are recommended for methyl methacrylate monomer to avoid sensitization and/or cumulative irritant contact dermatitis on the hands.

  5. Modification of gelatin by reaction with 1,6-diisocyanatohexane.

    PubMed

    Bertoldo, Monica; Bronco, Simona; Gragnoli, Tania; Ciardelli, Francesco

    2007-03-08

    1,6-Diisocyanatohexane and dimethyl sulfoxide were exploited as crosslinking agent and reaction solvent, respectively, for gelatin modification. Crosslinked samples were fractionated and analyzed by thermogravimetric analysis, infrared spectroscopy, acid and base titrations, and swelling measurements. The yield of crosslinking was found to increase with increasing diisocyanate and gelatin concentrations and the amount of bound crosslinker was evaluated. The chemical analysis of the reaction products allowed the process parameters to be related to the properties of the textile/gelatin composites. For this purpose poly(propylene)-, poly(ethylene terephthalate)-, and cotton-based textiles were treated to prepare soft and dimensionally stable supported materials with a gel phase composed of gelatin.

  6. Hair follicles stimulation effects of gelatin nanofibers containing silver nanoparticles.

    PubMed

    Tura, V; Hagiu, B A; Mangalagiu, I I

    2010-04-01

    In the present work we studied gelatin nanofibers containing silver nanoparticles of 14 +/- 6 nm mean diameter, prepared by electrospinning. The electrospinnable solution was obtained by drop-wise adding a AgNO3/acetic acid solution to gelatin which had previously been dissolved in a mixture of formic acid and acetic acid. The silver metallic nanoparticles were formed due to the reducing action of the formic acid. The resulted material was characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) and X-ray diffraction (XRD). Subcutaneous implants in rabbits demonstrated that the gelatin nanofibers containing silver nanoparticles were resorbed with no inflammatory reactions. An increased number of secondary hair follicles developed in tissue regions close to implants, suggesting the existence of a stimulation effect of silver nanoparticles on hair follicles.

  7. Synthesis, characterization, and morphology study of poly(acrylamide-co-acrylic acid)-grafted-poly(styrene-co-methyl methacrylate) "raspberry"-shape like structure microgels by pre-emulsified semi-batch emulsion polymerization.

    PubMed

    Ramli, Ros Azlinawati; Hashim, Shahrir; Laftah, Waham Ashaier

    2013-02-01

    A novel microgels were polymerized using styrene (St), methyl methacrylate (MMA), acrylamide (AAm), and acrylic acid (AAc) monomers in the presence of N,N'-methylenebisacrylamide (MBA) cross-linker. Pre-emulsified monomer was first prepared followed by polymerizing monomers using semi-batch emulsion polymerization. Fourier Transform Infrared Spectroscopy (FTIR) and (1)H Nuclear Magnetic Resonance (NMR) were used to determine the chemical structure and to indentify the related functional group. Grafting and cross-linking of poly(acrylamide-co-acrilic acid)-grafted-poly(styrene-co-methyl methacrylate) [poly(AAm-co-AAc)-g-poly(St-co-MMA)] microgels are approved by the disappearance of band at 1300 cm(-1), 1200 cm(-1) and 1163 cm(-1) of FTIR spectrum and the appearance of CH peaks at 5.5-5.7 ppm in (1)H NMR spectrum. Scanning Electron Microscope (SEM) images indicated that poly(St-co-MMA) particle was lobed morphology coated by cross-linked poly(AAm-co-AAc) shell. Furthermore, SEM results revealed that poly(AAm-co-AAc)-g-poly(St-co-MMA) is composite particle that consist of "raspberry"-shape like structure core. Internal structures of the microgels showed homogeneous network of pores, an extensive interconnection among pores, thicker pore walls, and open network structures. Water absorbency test indicated that the sample with particle size 0.43 μm had lower equilibrium water content, % than the sample with particle size 7.39 μm. Copyright © 2012 Elsevier Inc. All rights reserved.

  8. Modification of gelatin-DNA interaction for optimised DNA extraction from gelatin and gelatin capsule.

    PubMed

    Mohamad, Nurhidayatul Asma; Mustafa, Shuhaimi; El Sheikha, Aly Farag; Khairil Mokhtar, Nur Fadhilah; Ismail, Amin; Ali, Md Eaqub

    2016-05-01

    Poor quality and quantity of DNA extracted from gelatin and gelatin capsules often causes failure in the determination of animal species using PCR. Gelatin, which is mainly derived from porcine and bovine, has been a matter of concern among customers in order to fulfill religious obligation and safety precaution against several transmissible infectious diseases associated with bovine species. Thus, optimised DNA extraction from gelatin is very important for successful real-time PCR detection of gelatin species. In this work, the DNA extraction method was optimised in terms of lysis incubation period and inclusion of pre-treatment pH modification of samples. The yield of DNA extracted from porcine gelatin was significantly increased when the pH of the samples was adjusted to pH 8.5 prior to DNA precipitation with isopropanol. The optimal pH for DNA precipitation from bovine gelatin solution was then determined at the original pH range of solution: pH 7.6 to 8. A DNA fragment of approximately 300 base pairs was available for PCR amplification. DNA extracted from gelatin and commercially available capsules has been successfully utilised for species detection using real-time PCR assay. However, significant adulterations of porcine and bovine in pure gelatin and capsules have been detected, which require further analytical techniques for validation. © 2015 Society of Chemical Industry. © 2015 Society of Chemical Industry.

  9. Photocrosslinked layered gelatin-chitosan hydrogel with graded compositions for osteochondral defect repair.

    PubMed

    Han, Fengxuan; Yang, Xiaoling; Zhao, Jin; Zhao, Yunhui; Yuan, Xiaoyan

    2015-04-01

    A layered gelatin-chitosan hydrogel with graded composition was prepared via photocrosslinking to simulate the polysaccharide/collagen composition of the natural tissue and mimic the multi-layered gradient structure of the cartilage-bone interface tissue. Firstly, gelatin and carboxymethyl chitosan were reacted with glycidyl methacrylate (GMA) to obtain methacrylated gelatin (Gtn-GMA) and carboxymethyl chitosan (CS-GMA). Then, the mixed solutions of Gtn-GMA in different methacrylation degrees with CS-GMA were prepared to form the superficial, transitional and deep layers of the hydrogel, respectively under the irradiation of ultraviolet light, while polyhedral oligomeric silsesquioxane was introduced in the deep layer to improve the mechanical properties. Results suggested that the pore sizes of the superficial, transitional and deep layers of the layered hydrogel were 115 ± 30, 94 ± 34, 51 ± 12 μm, respectively and their porosities were all higher than 80 %. The compressive strengths of them were 165 ± 54, 565 ± 50 and 993 ± 108 kPa, respectively and the strain of the gradient hydrogel decreased along the thickness direction, similar to the natural tissue. The in vitro cytotoxicity results showed that the hydrogel had good cytocompatibility and the in vivo repair results of osteochondral defect demonstrated remarkable recovery by using the gradient gelatin-chitosan hydrogel, especially when the hydrogel loading transforming growth factor-β1. Therefore, it was suggested that the prepared layered gelatin-chitosan hydrogel in this study could be potentially used to promote cartilage-bone interface tissue repair.

  10. Gas chromatographic determination of pentachlorophenol in gelatin.

    PubMed

    Borsetti, A P; Thurston, L S

    1984-01-01

    A method is described for the determination of pentachlorophenol (PCP) in gelatin. The method employs acid and heat to hydrolyze the gelatin matrix, a base partition and wash for separation and cleanup, and a reacidification and extraction with hexane for direct determination of PCP, without preparation of a derivative, using gas chromatography (GC) with a 1% SP- 124ODA liquid phase and a 63Ni electron capture detector. Recoveries averaged 106% for fortifications between 0.02 and 1.0 ppm. The limit of quantitation is 20 ppb. The limit of detection is 4-6 ppb. The method, which has undergone a successful intralaboratory trial, is simple and rapid, and requires only general laboratory reagents and equipment. GC of the acetate derivative of PCP is used for confirmation of identity.

  11. Methacrylate-based monolithic layers for planar chromatography of polymers.

    PubMed

    Maksimova, E F; Vlakh, E G; Tennikova, T B

    2011-04-29

    A series of macroporous monolithic methacrylate-based materials was synthesized by in situ free radical UV-initiated copolymerization of functional monomers, such as glycidyl methacrylate (GMA), butyl methacrylate (BuMA), 2-aminoethyl methacrylate (AEMA), 2-hydroxyethyl methacrylate (HEMA) and 2-cyanoethyl methacrylate (CEMA), with crosslinking agent, namely, ethylene glycol dimethacrylate (EDMA). The materials obtained were applied as the stationary phases in simple and robust technique - planar chromatography (PLC). The method of separation layer fabrication representing macroporous polymer monolith bound to the specially prepared glass surface was developed and optimized. The GMA-EDMA and BuMA-EDMA matrixes were successfully applied for the separation of low molecular weight compounds (the mixture of several dies), as well as poly(vinylpyrrolidone) and polystyrene homopolymers of different molecular weights using reversed-phase mechanism. The materials based on copolymers AEMA-HEMA-EDMA and CEMA-HEMA-EDMA were used for normal-phase PLC separation of 2,4-dinitrophenyl amino acids and polystyrene standards.

  12. The bioactive composite film prepared from bacterial cellulose and modified by hydrolyzed gelatin peptide.

    PubMed

    Lin, Shih-Bin; Chen, Chia-Che; Chen, Li-Chen; Chen, Hui-Huang

    2015-05-01

    The hydrolyzed gelatin peptides, obtained from the hydrolysis of Tilapia nilotica skin gelatin with alcalase and pronase E, were fractionated using an ultrafiltration system into hydrolyzed gelatin peptides-a (10 kDa membrane), hydrolyzed gelatin peptides-b1, and hydrolyzed gelatin peptides-b2 (5 kDa membrane) fractions. The highest oxygen radical absorbance capacity was observed in hydrolyzed gelatin peptides-b2, which contained more nonpolar amino acids than the other hydrolyzed gelatin peptides. Hydrolyzed gelatin peptides-b2 at a concentration of 12.5 mg/ml exhibited the highest proliferation ability and increased the expression of Type I procollagen mRNA, which indicated an enhanced collagen synthesis. Hydrolyzed gelatin peptides protected Detroit 551 cells from 2,2'-azobis(2-amidinopropane) dihydrochloride-induced oxidative damage and increased cell viability. Hydroxylpropylmethyl cellulose-modified bacterial cellulose and dried fabricated biofilm were less eligible for Detroit 551 cell proliferation than bacterial cellulose. The release of hydrolyzed gelatin peptides in bacterial cellulose film was slower than that in hydroxylpropylmethyl cellulose-modified bacterial cellulose and dried fabricated biofilm; thus, bacterial cellulose film and hydroxylpropylmethyl cellulose-modified bacterial cellulose and dried fabricated biofilm are suitable candidates for applications in delayed release type and rapid release type biofilms, respectively.

  13. Characteristics and Gel Properties of Gelatin from Goat Skin as Influenced by Alkaline-pretreatment Conditions

    PubMed Central

    Mad-Ali, Sulaiman; Benjakul, Soottawat; Prodpran, Thummanoon; Maqsood, Sajid

    2016-01-01

    Characteristics and properties of gelatin from goat skin pretreated with NaOH solutions (0.50 and 0.75 M) for various times (1 to 4 days) were investigated. All gelatins contained α-chains as the predominant component, followed by β-chain. Gelling and melting temperatures of those gelatins were 23.02°C to 24.16°C and 33.07°C to 34.51°C, respectively. Gel strength of gelatins increased as NaOH concentration and pretreatment time increased (p<0.05). Pretreatment for a longer time yielded gelatin with a decrease in L*-value but an increase in b*-value. Pretreatment of goat skin using 0.75 M NaOH for 2 days rendered the highest yield (15.95%, wet weight basis) as well as high gel strength (222.42 g), which was higher than bovine gelatin (199.15 g). Gelatin obtained had the imino acid content of 226 residues/1,000 residues and the gelatin gel had a fine and ordered structure. Therefore, goat skin gelatin could be used as a potential replacer of commercial gelatin. PMID:26954127

  14. Extraction and characterization of gelatin biopolymer from black tilapia (Oreochromis mossambicus) scales

    SciTech Connect

    Sockalingam, K. Abdullah, H. Z.

    2015-07-22

    Black tilapia (Oreochromis mossambicus) fish wastes (scales) were evaluated for its suitability as sources of gelatin. Scales were subjected to acid treatment for demineralization before it undergoes thermal extraction process. The raw scales were characterized via Scanning Electron Microscopy (SEM), which demarcated the cycloid pattern of the scales. SEM images also reveal the presence of collagen fiber in the fish scale. The black tilapia fish scales yields 11.88 % of gelatin, indicating the possibility of this fish species as sources of gelatin. Further characterizations were done on both raw scale and extracted gelatin through Fourier Transform Infrared Spectroscopy (FTIR) and proximate analysis. The scale gelatin shows high protein content (86.9 %) with low moisture (8.2 %) and ash (1.4 %). This further proves the effectiveness of the demineralization and extraction method used. The black tilapia fish scale is found to be a prospective source of gelatin with good chemical and functional properties.

  15. Extraction and characterization of gelatin biopolymer from black tilapia (Oreochromis mossambicus) scales

    NASA Astrophysics Data System (ADS)

    Sockalingam, K.; Abdullah, H. Z.

    2015-07-01

    Black tilapia (Oreochromis mossambicus) fish wastes (scales) were evaluated for its suitability as sources of gelatin. Scales were subjected to acid treatment for demineralization before it undergoes thermal extraction process. The raw scales were characterized via Scanning Electron Microscopy (SEM), which demarcated the cycloid pattern of the scales. SEM images also reveal the presence of collagen fiber in the fish scale. The black tilapia fish scales yields 11.88 % of gelatin, indicating the possibility of this fish species as sources of gelatin. Further characterizations were done on both raw scale and extracted gelatin through Fourier Transform Infrared Spectroscopy (FTIR) and proximate analysis. The scale gelatin shows high protein content (86.9 %) with low moisture (8.2 %) and ash (1.4 %). This further proves the effectiveness of the demineralization and extraction method used. The black tilapia fish scale is found to be a prospective source of gelatin with good chemical and functional properties.

  16. The acute aquatic toxicity of a series of acrylate and methacrylate esters

    SciTech Connect

    Staples, C.A.; McLaughlin, J.E.; Hamilton, J.D.

    1994-12-31

    Acute aquatic toxicity data for several acrylate and methacrylate esters were reviewed. Acrylates included acrylic acid, ethyl-, and butyl-acrylate. Methacrylates included methacrylic acid, methyl-, and butyl-methacrylate. Tests were 48 hr or 96 hr standard flow through (invertebrates and fish) assays (measured exposure concentrations). These data are currently used in a risk assessment of acrylate/methacrylate environmental safety. Algal growth (Selanastrum capricomutum) 96 hr EC{sub 50}s were 0.17 mg/L (NOEC < 0.13 mg/L) for acrylic acid, 11.0 mg/L (NOEC < 6.5 mg/L) for ethyl acrylate, and 5.2 mg/L (NOEC < 3.8 mg/L) for butyl acrylate. Invertebrate (Daphnia magna) 48 hr LC{sub 50}s were 95.0 mg/L (NOEC 23.0 mg/L) for acrylic acid, 7.9 mg/L (NOEC 3.4 mg/L) for ethyl acrylate, and 8.2 mg/L (NOEC 2.4 mg/L) for butyl acrylate. Rainbow trout (Oncorhynchus mykiss) 96 hr LC{sub 50}s were 27.0 mg/L (NOEC 6.3 mg/L) for acrylic acid, 4.6 mg/L (NOEC 0.78 mg/L) for ethyl acrylate, and 5.2 mg/L (NOEC 3.8 mg/L) for butyl acrylate. Algae 96 hr EC{sub 50}s were 0.59 mg/L (NOEC 0.38 mg/L) for methacrylic acid, 170.0 mg/L (NOEC 100.0 mg/L) for methyl methacrylate, and 130.0 mg/L for butyl methacrylate. Daphnia magna 48 hr LC{sub 50}s were > 130.0 mg/L (NOEC 130.0 mg/L) for methacrylic acid, 69.0 mg/L (NOEC 48.0 mg/L) for methyl methacrylate, and 32.0 mg/L (NOEC 23.0 mg/L) for butyl methacrylate. Trout 96 hr LC{sub 50}s were 85.0 mg/L (NOEC 12.0 mg/L) for methacrylic acid and > 79.0 mg/L (NOEC 40.0 mg/L) for methyl methacrylate. The fathead minnow (Pimephales promelas) 96 hr LC{sub 50} was 11.0 mg/L for butyl methacrylate.

  17. Physical and Chemical Properties of Pollock and Salmon Skin Gelatin Films

    USDA-ARS?s Scientific Manuscript database

    This study evaluated the barrier and mechanical properties of Alaska pollock (Theragra chalcogramma) and Alaska pink salmon (Oncorhynchus gorbuscha) gelatin films and related these to amino acid composition and gel properties. Gelatin was made by extracting heat-soluble proteins from the skins of p...

  18. Silver-halide gelatin holograms

    NASA Astrophysics Data System (ADS)

    Chang, B. J.; Winick, K.

    1980-05-01

    The use of a silver-halide gelatin for volume phase holograms having a wide spectral response and lower exposure requirements than alternatives and using commercially available silver salts, is proposed. The main difference between the dichromated gelatin and silver-halide processes is the creation of a hologram latent image, which is given in the form of a hardness differential between exposed and unexposed regions in the silver halide hologram; the differential is in turn created by the reaction products of either tanning development or tanning bleach, which harden the gelatin with link-bonds between molecules.

  19. The role of alkyl chain length of monothiol-terminated alkyl carboxylic acid in the synthesis, characterization, and application of gelatin-g-poly(N-isopropylacrylamide) carriers for antiglaucoma drug delivery.

    PubMed

    Luo, Li-Jyuan; Lai, Jui-Yang

    2017-02-01

    To improve ocular bioavailability and extend pharmacological response, this study aims to investigate the role of alkyl chain length of monothiol-terminated alkyl carboxylic acids in the synthesis, characterization, and application of gelatin-g-poly(N-isopropylacrylamide) (GN) biodegradable in situ gelling carriers for antiglaucoma drug delivery. In the presence of mercaptoacetic acid (MAA), mercaptopropionic acid (MPA), mercaptobutyric acid (MBA), or mercaptohexanoic acid (MHA) as a chain transfer agent, the carboxylic end-capped poly(N-isopropylacrylamide) samples were prepared by free radical polymerization technique. Our results showed that with increasing alkyl chain length, the hydrophobicity of thermo-responsive polymer segments significantly increased, mainly due to an increase in CH stretching frequencies. In addition, the greater hydrophobic association favored the decrease in both phase transition temperature and weight loss of GN copolymers, thereby accelerating their temperature-triggered gelation process and retarding the degradation progress under physiological conditions. The benefits from these features allowed the pilocarpine carriers to increase drug payload and extend drug release. Irrespective of carbon number of monothiol-terminated alkyl carboxylic acid, the synthesized GN materials exhibited high tolerance to corneal endothelial cells without any evidence of inhibited proliferation, viability loss, inflammatory stimulation, and functional abnormality, indicating good biocompatibility. Results of clinical observations and histological examinations demonstrated that the therapeutic efficacies in treating glaucomatous damage are in response to in vivo drug release profiles from various intracamerally injected GN carriers. The research findings suggest the influence of alkyl chain length of chain transfer agent-mediated polymer hydrophobicity and degradability on pharmacological bioavailability and action of pilocarpine in a glaucomatous rabbit

  20. Nanolayer formation on titanium by phosphonated gelatin for cell adhesion and growth enhancement.

    PubMed

    Zhou, Xiaoyue; Park, Shin-Hye; Mao, Hongli; Isoshima, Takashi; Wang, Yi; Ito, Yoshihiro

    2015-01-01

    Phosphonated gelatin was prepared for surface modification of titanium to stimulate cell functions. The modified gelatin was synthesized by coupling with 3-aminopropylphosphonic acid using water-soluble carbodiimide and characterized by (31)P nuclear magnetic resonance and gel permeation chromatography. Circular dichroism revealed no differences in the conformations of unmodified and phosphonated gelatin. However, the gelation temperature was changed by the modification. Even a high concentration of modified gelatin did not form a gel at room temperature. Time-of-flight secondary ion mass spectrometry showed direct bonding between the phosphonated gelatin and the titanium surface after binding. The binding behavior of phosphonated gelatin on the titanium surface was quantitatively analyzed by a quartz crystal microbalance. Ellipsometry showed the formation of a several nanometer layer of gelatin on the surface. Contact angle measurement indicated that the modified titanium surface was hydrophobic. Enhancement of the attachment and spreading of MC-3T3L1 osteoblastic cells was observed on the phosphonated gelatin-modified titanium. These effects on cell adhesion also led to growth enhancement. Phosphonation of gelatin was effective for preparation of a cell-stimulating titanium surface.

  1. Nanolayer formation on titanium by phosphonated gelatin for cell adhesion and growth enhancement

    PubMed Central

    Zhou, Xiaoyue; Park, Shin-Hye; Mao, Hongli; Isoshima, Takashi; Wang, Yi; Ito, Yoshihiro

    2015-01-01

    Phosphonated gelatin was prepared for surface modification of titanium to stimulate cell functions. The modified gelatin was synthesized by coupling with 3-aminopropylphosphonic acid using water-soluble carbodiimide and characterized by 31P nuclear magnetic resonance and gel permeation chromatography. Circular dichroism revealed no differences in the conformations of unmodified and phosphonated gelatin. However, the gelation temperature was changed by the modification. Even a high concentration of modified gelatin did not form a gel at room temperature. Time-of-flight secondary ion mass spectrometry showed direct bonding between the phosphonated gelatin and the titanium surface after binding. The binding behavior of phosphonated gelatin on the titanium surface was quantitatively analyzed by a quartz crystal microbalance. Ellipsometry showed the formation of a several nanometer layer of gelatin on the surface. Contact angle measurement indicated that the modified titanium surface was hydrophobic. Enhancement of the attachment and spreading of MC-3T3L1 osteoblastic cells was observed on the phosphonated gelatin-modified titanium. These effects on cell adhesion also led to growth enhancement. Phosphonation of gelatin was effective for preparation of a cell-stimulating titanium surface. PMID:26366080

  2. Recombinant human gelatin substitute with photoreactive properties for cell culture and tissue engineering.

    PubMed

    Kitajima, Takashi; Obuse, Sei; Adachi, Takahiro; Tomita, Masahiro; Ito, Yoshihiro

    2011-10-01

    The human recombinant collagen I α1 chain monomer (rh-gelatin) was modified by the incorporation of an azidophenyl group to prepare photoreactive human gelatin (Az-rh-gelatin), with approximately 90% of the lysine residues conjugated with azidobenzoic acid. Slight changes in conformation (circular dichroism spectra) and thermal properties (gelation and melting points) were noticed after modification. Ultraviolet (UV) irradiation could immobilize the Az-rh-gelatin on polymer surfaces, such as polystyrene and polytetrafluoroethylene. Az-rh-gelatin was stably retained on the polymer surfaces, while unmodified gelatin was mostly lost by brief washing. Human mesenchymal cells grew more efficiently on the immobilized surface than on the coated surface. The immobilized Az-rh-gelatin on the polymer surfaces was able to capture engineered growth factors with collagen affinity, and the bound growth factors stimulated the growth of cells dose-dependently. It was also possible to immobilize Az-rh-gelatin in micropatterns (stripe, grid, and so on) using photomasks, and the cells grew according to the patterns. These results suggest that the photoreactive human gelatin, in combination with collagen-binding growth factors, will be clinically useful for surface modification of synthetic materials for cell culture systems and tissue engineering.

  3. Biomechanical characteristics of cement/gelatin mixture for prevention of cement leakage in vertebral augmentation.

    PubMed

    Meng, Bin; Qian, Ming; Xia, Shao-Xiang; Yang, Hui-Lin; Luo, Zong-Ping

    2013-10-01

    This study evaluated whether or not the addition of gelatin micro-particles into the polymethyl methacrylate (PMMA) could reduce cement infiltration in cancellous bone of vertebra. Gelatin micro-particles were prepared in various sizes and mixed with PMMA in different densities. Dynamic viscosity of the mixture was measured by a rotational rheometer. Fresh bovine vertebral bodies were sectioned into cylindrical samples. Permeability of the mixture through the samples was tested on a mechanical test machine, and calculated using Darcy's law. The PMMA/gelatin mixture also underwent compressive and bending tests, and their structures were examined by scanning electron microscopy. The cement/gelatin mixture increased the viscosity. Significant reduction of cement permeability in cancellous bone was determined after the addition of the micro-particles. Micro-particles of 2 % in density and 125-250 μm in size decreased the permeability by 1/3 without any significant change of the cement viscosity. The biomechanical strength was unchanged in compression but decreased by up to 20 % in bending. Gelatin micro-particles significantly increased the cement viscosity, reduced the permeability in cancellous bone of vertebra, decreased the flexural strength, but did not affect the compressive strength. Although it suggested a manageable approach in vertebral augmentation, the outcome should be further verified on a cadaveric model or an animal model before the mixture could be used safely and effectively in the clinical treatment.

  4. Determination of bioavailability and identification of collagen peptide in blood after oral ingestion of gelatin.

    PubMed

    Wang, Lin; Wang, Qing; Liang, Qiufang; He, Yuanqing; Wang, Zhenbin; He, Song; Xu, Junmin; Ma, Haile

    2015-10-01

    Gelatin has long been widely used in foods, pharmaceuticals, cosmetics, and other products. However, there are few reports on its bioavailability and bioavailable forms. In this study, the bioavailability of gelatin was indirectly evaluated by the determining the bioavailability of total hydroxyproline in gelatin using a pharmacokinetic method after oral administration to rats. The relative and absolute bioavailability of gelatin were 74.12% and 85.97%, respectively. The amino acid profile of plasma indicated that 41.91% of the digested gelatin was absorbed from the intestine in the form of peptide, and there was a good linear correlation between the absorbed amount of an amino acid and its content in gelatin (R(2) = 0.9566). Moreover, 17 types of collagen peptide were purified by multi-step chromatography and identified with ultra-performance liquid chromatography-electrospray ionisation-mass spectrometry. Gelatin had high oral bioavailability. Nearly half of digested gelatin was absorbed from the intestine in the form of various collagen peptides. © 2014 Society of Chemical Industry.

  5. Comparison between gelatines extracted from mackerel and blue whiting bones after different pre-treatments.

    PubMed

    Khiari, Zied; Rico, Daniel; Martin-Diana, Ana Belen; Barry-Ryan, Catherine

    2013-08-15

    Gelatines were extracted from mackerel and blue whiting bones after chemical or enzymatic pre-treatments and their functional properties (solubility, foaming and emulsifying properties) were analysed. The pre-treatment significantly (p<0.05) affected the composition and the functional properties of the extracted gelatines. The amino acid analyses showed that chemically pre-treated bone gelatines had higher imino acids (proline and hydroxyproline) contents compared to those extracted after the enzymatic pre-treatment, for both fish species. It was observed that all gelatines had higher solubility at low pH with a maximum value observed at pH 2. A significant effect of ionic strength was observed. Increasing the NaCl concentration to more than 1% resulted in a significant decrease of the solubility. Mackerel bone gelatines showed lower foaming capacity (FC) and higher foaming stability (FS) than blue whiting bone gelatines. Increasing the concentration of gelatine decreased the emulsifying activity index (EAI) but increased the stability index (ESI). The use of enzymes in the pre-treatment process gave gelatines with significantly (p<0.05) higher EAI and ESI.

  6. An In Vivo Study of Composite Microgels Based on Hyaluronic Acid and Gelatin for the Reconstruction of Surgically Injured Rat Vocal Folds

    PubMed Central

    Coppoolse, Jiska M. S.; Van Kooten, T. G.; Heris, Hossein K.; Mongeau, Luc; Li, Nicole Y. K.; Thibeault, Susan L.; Pitaro, Jacob; Akinpelu, Olubunmi; Daniel, Sam J.

    2016-01-01

    Purpose The objective of this study was to investigate local injection with a hierarchically microstructured hyaluronic acid–gelatin (HA-Ge) hydrogel for the treatment of acute vocal fold injury using a rat model. Method Vocal fold stripping was performed unilaterally in 108 Sprague-Dawley rats. A volume of 25 ml saline (placebo controls), HA-bulk, or HA-Ge hydrogel was injected into the lamina propria (LP) 5 days after surgery. The vocal folds were harvested at 3, 14, and 28 days after injection and analyzed using hematoxylin and eosin staining and immunohistochemistry staining for macrophages, myofibroblasts, elastin, collagen type I, and collagen type III. Results The macrophage count was statistically significantly lower in the HA-Ge group than in the saline group (p < .05) at Day 28. Results suggested that the HA-Ge injection did not induce inflammatory or rejection response. Myofibroblast counts and elastin were statistically insignificant across treatment groups at all time points. Increased elastin deposition was qualitatively observed in both HA groups from Day 3 to Day 28, and not in the saline group. Significantly more elastin was observed in the HA-bulk group than in the uninjured group at Day 28. Significantly more collagen type I was observed in the HA-bulk and HA-Ge groups than in the saline group (p < .05) at Day 28. The collagen type I concentration in the HA-Ge and saline groups was found to be comparable to that in the uninjured controls at Day 28. The concentration of collagen type III in all treatment groups was similar to that in uninjured controls at Day 28. Conclusion Local HA-Ge and HA-bulk injections for acute injured vocal folds were biocompatible and did not induce adverse response. PMID:24687141

  7. Effect of chemical cross-linking on gelatin membrane solubility with a non-toxic and non-volatile agent: terephthalaldehyde.

    PubMed

    Biscarat, Jennifer; Galea, Benjamin; Sanchez, José; Pochat-Bohatier, Celine

    2015-03-01

    In this paper, terephthalaldehyde (TPA) is proposed as non-toxic and non-volatile gelatin cross-linker. Optimal cross-linking parameters (TPA/gelatin ratio, temperature) were first determined from in situ rheological measurements on gelatin solutions and from chemical tests with 2,4,6-trinitrobenzenesulfonic acid (TNBS assays) on gelatin gel. The highest cross-linking ratio was achieved for a concentration of 0.005 g TPA/g gelatin at 60°C. The impact of TPA cross-linking on gelatin membrane functional properties (water swelling ratio, water vapor sorption and mechanical properties) was measured. TPA cross-linking increased 17 times the liquid water resistance duration of gelatin films, and delayed the entry of vapor water in the polymer matrix for 7 days, indicating that TPA increased the hydrophobic character of the gelatin matrix.

  8. Hybrid molecularly imprinted polymers synthesized with 3-aminopropyltriethoxysilane-methacrylic acid monomer for miniaturized solid-phase extraction: A new and economical sample preparation strategy for determination of acyclovir in urine.

    PubMed

    Yan, Hongyuan; Wang, Mingyu; Han, Yehong; Qiao, Fengxia; Row, Kyung Ho

    2014-06-13

    The miniaturized molecularly imprinted solid-phase extraction (mini-MISPE) coupled with high-performance liquid chromatography was proposed for the determination of acyclovir in urine. 1.5-mL tapered plastic centrifuge tube filled with hybrid molecularly imprinted polymers (HMIPs) was used as the cartridge of mini-MISPE, and the HMIPs synthesized with 3-aminopropyltriethoxy silane-methacrylic acid as monomer exhibited good recognition and selectivity for acyclovir. Under the optimized condition, good linear calibration was obtained in a range of 0.5-15μgmL(-1) with the correlation coefficient of 0.9994, and the recoveries at three spiked levels were 91.6-103.3% in urine with the relative standard deviation (RSD) of ≤3.5%. Excellent intra-day and inter-day repeatability were achieved with RSD of ≤2.6% and 4.0% in three different concentrations. This method combined the advantages of HMIPs and mini-MISPE, and it could become an alternative tool for analyzing the residues of acyclovir in complex urine matrices. Copyright © 2014 Elsevier B.V. All rights reserved.

  9. Enhancement of light harvesting efficiency of silicon solar cell utilizing arrays of poly(methyl methacrylate-co-acrylic acid) nano-spheres and nano-spheres with embedded silver nano-particles

    NASA Astrophysics Data System (ADS)

    Lee, Chee-Leong; Goh, Wee-Sheng; Chee, Swee-Yong; Yik, Lai-Kuan

    2017-02-01

    An array of uniformly distributed monolayer of poly(methyl methacrylate-co-acrylic acid) nano-spheres were deposited onto an amorphous silicon photovoltaic cell utilizing dip coating technique. The electrical characteristics of the coated photovoltaic cell reveal that the nano-spheres with an average diameter size of 101 nm exhibits excellent light harvesting characteristics if compared to the nano-spheres of other sizes. The power conversion efficiency from such integration of the nano-structures (i.e. 3.14% per PV cell) indicates that at least 1.6 times of improvement (or relative enhancement of 57%) can be achieved comparatively to the uncoated photovoltaic cell (i.e. 2% per PV cell). Further increment of the power conversion efficiency of the solar cell has been attained with the incorporation of the silver nano-particles into the nano-spheres of similar average size. With the inclusion of the silver nano-particles into such nano-spheres, the power conversion efficiency of the solar cell has attained 5.57% per PV cell, which is about 2.8 times (or relative enhancement of 179%) if compared to the uncoated samples. Hence, this novel and controllable technique of fabricating omnidirectional light-harvesting nano-spheres with embedded silver nano-particles will indubitably be beneficial to various types of optoelectronic devices.

  10. Influence of microgel architecture and oil polarity on stabilization of emulsions by stimuli-sensitive core-shell poly(N-isopropylacrylamide-co-methacrylic acid) microgels: Mickering versus Pickering behavior?

    PubMed

    Schmidt, Sabrina; Liu, Tingting; Rütten, Stephan; Phan, Kim-Ho; Möller, Martin; Richtering, Walter

    2011-08-16

    Charged poly(N-isopropylacrylamide-co-methacrylic acid) [P(NiPAM-co-MAA)] microgels can stabilize thermo- and pH-sensitive emulsions. By placing charged units at different locations in the microgels and comparing the emulsion properties, we demonstrate that their behaviors as emulsion stabilizers are very different from molecular surfactants and rigid Pickering stabilizers. The results show that the stabilization of the emulsions is independent of electrostatic repulsion although the presence and location of charges are relevant. Apparently, the charges facilitate emulsion stabilization via the extent of swelling and deformability of the microgels. The stabilization of these emulsions is linked to the swelling and structure of the microgels at the oil-water interface, which depends not only on the presence of charged moieties and on solvent polarity but also on the microgel (core-shell) morphology. Therefore, the internal soft and porous structure of microgels is important, and these features make microgel-stabilized emulsions characteristically different from classical, rigid-particle-stabilized Pickering emulsions, the stability of which depends on the surface properties of the particles.

  11. Construction of a portable sample preparation device with a magnetic poly(methacrylic acid-co-ethylene dimethacrylate) monolith as the extraction medium and its application in the enrichment of UV filters in water samples.

    PubMed

    Li, Jing; Xu, Li; Yu, Qiong-Wei; Shi, Zhi-Guo; Zhang, Ting; Liu, Yan

    2014-10-01

    A portable sample preparation device with a magnetic polymer monolith as the extraction medium was constructed. The monolith was synthesized by polymerizing methacrylic acid and ethylene dimethacrylate around a cylindrical magnet. In this way, the monolith with a magnetic core could be readily attached to the extraction device by magnetism. The constructed device was evaluated for the enrichment of UV filters in water samples, followed by high-performance liquid chromatographic analysis. The extraction efficiency for the targets was satisfactory with no matrix interference. Good linearities were obtained for the UV filters with the correlation coefficients >0.9986. The limits of detection and quantification for the UV filters were 0.3-0.8 and 1.0-2.4 ng/mL, respectively. The recoveries of the UV filters from the spiked water samples at the concentration of 100 ng/mL were 95.3-101.7%, with relative standard deviations <10%. Accordingly, the proposed portable device was demonstrated to be suitable for on-site simultaneous sampling, purification, and preconcentration within a single step.

  12. Preparation of thermoresponsive Fe3O4/P(acrylic acid-methyl methacrylate-N-isopropylacrylamide) magnetic composite microspheres with controlled shell thickness and its releasing property for phenolphthalein.

    PubMed

    Zhang, Baoliang; Zhang, Hepeng; Fan, Xinlong; Li, Xiangjie; Yin, Dezhong; Zhang, Qiuyu

    2013-05-15

    In this work, Fe3O4/P(acrylic acid-methyl methacrylate-N-isopropylacrylamide) (Fe3O4/P(AA-MMA-NIPAm)) thermoresponsive magnetic composite microspheres have been prepared by controlled radical polymerization in the presence of 1,1-diphenylethene (DPE). The shell thickness of thermosensitive polymer (PNIPAm), which was on the surface of the microspheres, can be controlled by using DPE method. The morphology and thermosensitive properties of the composite microspheres, polymerization mechanism of the shell were characterized by TEM, FTIR, VSM, Laser Particle Sizer, TGA, NMR, and GPC. The microspheres with narrow particle size distribution show high saturation magnetization and superparamagnetism. The thermosensitive properties of the composite microspheres can be adjusted indirectly via controlling the addition amount of monomer (NIPAm) in the second step during controlled radical polymerization. Phenolphthalein was chosen as a model drug to investigate drug release behavior of the thermoresponsive magnetic composite microspheres with different shell thickness. Controlled drug release testing reveals that the release behavior depends on the thickness of polymer on the surface of the microspheres. Copyright © 2013 Elsevier Inc. All rights reserved.

  13. Synthesis of acrylates and methacrylates from coal-derived syngas

    SciTech Connect

    Spivey, J.J.; Gogate, M.R.; Jang, B.W.L.

    1995-12-31

    Acrylates and methacrylates are among the most widely used chemical intermediates in the world. One of the key chemicals of this type is methyl methacrylate. Of the 4 billion pounds produced each year, roughly 85% is made using the acetone-cyanohydrin process, which requires handling of large quantities of hydrogen cyanide and produces ammonium sulfate wastes that pose an environmental disposal challenge. The U.S. Department of Energy and Eastman Chemical Company are sharing the cost of research to develop an alternative process for the synthesis of methyl methacrylate from syngas. Research Triangle Institute is focusing on the synthesis and testing of active catalysts for the condensation reactions, and Bechtel is analyzing the costs to determine the competitiveness of several process alternatives. Results thus far show that the catalysts for the condensation of formaldehyde and the propionate are key to selectively producing the desired product, methacrylic acid, with a high yield. These condensation catalysts have both acid and base functions and the strength and distribution of these acid-base sites controls the product selectivity and yield.

  14. Starch gelatinization under thermal stress.

    PubMed

    Faroongsarng, D; Wongpoowarak, W; Mitrevej, A

    1999-01-01

    The behavior under thermal stress of starch dispersed in water was studied by differential scanning calorimetry (DSC) to estimate the heat transported through the aqueous medium in gelatinization, and to characterize the range of gelatinization temperatures. In DSC scanning mode, the endotherm of 10% starch in aqueous dispersion showed the tracing of gelatinization at between 67 and 80 degrees C, having an onset at approximately 69 degrees C. In the isothermal mode, characteristically distinct isothermal heat flow profiles were revealed. It was hypothesized that the thermal influx proposed as being analogous to the diffusion process may affect the profiles. The profiles were transformed and nonlinearly fitted according to the square root of time model to characterize a so-called t-parameter, which was related to mean square displacement of molecular distribution. The t-parameter of starch in excess of water decreased compared to that of water only. The plot of difference in these t-parameters, expressed as delta, against temperature showed a dramatically decreased delta at the temperature between 66.7 and 75.2 degrees C, which coincided with the findings from scanning mode DSC. It was further hypothesized that the decreased delta may be due to the gelatinizing process. According to the theory of polymer solution, the critical temperature (theta) at 75.2 degrees C, where the free energy became theoretically negative, i.e., the starch became spontaneously dissolved, was drawn. This theta was located within the range of gelatinizing temperatures. It was deduced that starch polymer may have dissolved during gelatinization. The dissolution from acetaminophen tablets prepared by starch paste was lower compared with that of negative controls (without paste). Moreover, the paste prepared at gelatinizing temperature (70 degrees C) seemed to inhibit acetaminophen dissolution from tablet matrices more than that prepared at subgelatinizing temperature (50 degrees C).

  15. Preparation of green and gelatin-free nanocrystalline cellulose capsules.

    PubMed

    Zhang, Yapei; Zhao, Qing; Wang, Huashan; Jiang, Xingyu; Cha, Ruitao

    2017-05-15

    The ambiguous source and uncontrolled solubility of gelatin make it crucial to develop gelatin capsule substitutes. Nanocrystalline cellulose (NCC) of excellent mechanical performance, good biocompatibility and green origin has drawn many attentions as a new class of biomaterials. In this work, NCC capsule was prepared by dipping method with PEG and glycerol as plasticizer. The effect of PEG and glycerol on the rheological property of NCC gel and the surface morphology of NCC capsule was evaluated. The disintegration time of NCC capsule meet the criteria in United States Pharmacopoeia (USP32-701).There is no significant difference in the release of sulfuric acid between gelatin capsule and NCC capsule. NCC capsule thus has the potential as a green platform for biomedical applications in drug delivery. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Sequential Delivery of BMP-2 and IGF-1 Using a Chitosan Gel with gelatin Microspheres Enhances Early osteoblastic Differentiation

    DTIC Science & Technology

    2016-06-07

    subject to a penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number 1. REPORT DATE...release of growth factors was controlled by BMP 2 containing basic gelatin microspheres and IGF 1 containing acidic gelatin microspheres, which were...proteins, BMP 2 and IGF 1 by this delivery system. The controlled releases of these two pro teins are regulated by the degree of cross linking of gelatin

  17. Characterization of edible film fabricated with channel catfish (Ictalurus punctatus) gelatin extract using selected pretreatment methods.

    PubMed

    Zhang, S; Wang, Y; Herring, J L; Oh, J-H

    2007-11-01

    Farm-raised catfish are important to the economy of the southeastern states in the United States, and catfish processing produces about 55% of by-products for inexpensive sale. Therefore, the utilization of catfish by-products is of great interest to the catfish industry. The objectives of this research were to determine the optimum pretreatment method to extract catfish gelatin for edible film application, and to characterize physical, mechanical, and barrier properties of edible films fabricated with catfish skin gelatin. Catfish skins obtained from a local plant were treated with 6 selected pretreatment methods. The main extraction was performed with deionized water at 50 degrees C after pretreatment. The gelatin yield was calculated and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) was performed to characterize molecular weight (MW) profile. Color, tensile strength (TS), elongation, and water barrier property were determined to characterize the fabricated catfish gelatin films. From the results of gelatin yield, color, SDS-PAGE, as well as mechanical and barrier properties of the film, the pretreatment method with 0.25 M NaOH and 0.09 M acetic acid, followed by extraction at 50 degrees C for 3 h, was determined as the optimum extraction method. The catfish gelatin exhibited higher MW fractions than commercial mammalian gelatin. The catfish gelatin extracts possessed film-forming properties determined by TS, elongation, and water vapor permeability (WVP) comparable to those of commercial mammalian gelatin. The selected formula for catfish gelatin film was determined as 1% gelatin and 20% glycerol, resulting in greatest TS and lowest WVP.

  18. Injectable photo crosslinked enhanced double-network hydrogels from modified sodium alginate and gelatin.

    PubMed

    Yuan, Liu; Wu, Yu; Gu, Qi-Sheng; El-Hamshary, Hany; El-Newehy, Mohamed; Mo, Xiumei

    2017-03-01

    Recently, photocrosslinked hydrogels have attracted more and more attention in biomedical applications. In this study, a serials of injectable hydrogels were fabricated from aldehyde methacrylate sodium alginate and amino gelatin (AMSA/AG) using a two-step process. Here, sodium alginate, a kind of natural polysaccharide, was modified by oxidizer to form aldehyde sodium alginate (ASA), and methacrylate groups were further grafted on the main chain of ASA. Gelatin, the denatured form of collagen, was modified with ethylenediamine (ED) to graft more amino groups. When AMSA and AG aqueous solutions were mixed, the Schiff base reaction occurred quickly to form the primary network between aldehyde groups in AMSA and amino groups in AG, and then a 365nm ultraviolet (UV) light was used to initiate the radical reaction of methacrylate groups in AMSA to produce the secondary network. The structures and properties of AMSA/AG hydrogels were evaluated by Fourier Transforms Infrared spectroscopy (FTIR) and (1)HNMR analysis. The swelling ratio confirmed the density of crosslinked networks, and the mechanical performance demonstrated that the UV initiated the double crosslinking network hydrogels have an improved mechanical properties compared to the single Schiff base networks hydrogels. The results showed that the photocrosslinked double network hydrogels have enhanced mechanical properties, good biocompatibility and controllable degradation rate. So, this hydrogels may have great potential utilized in regenerative medicine as therapeutic materials. Copyright © 2016 Elsevier B.V. All rights reserved.

  19. On the action of ozone on gelatin.

    PubMed

    Cataldo, Franco

    2007-07-01

    Gelatin, the lower molecular weight derivative of collagen, was treated with ozone and the structural changes were studied with polarimetry, electronic absorption and FT-IR spectroscopy. The resulting ozonized gelatins were studied by thermal analysis (DSC and TGA) in comparison to a reference gelatin. It has been found that at relatively low ozone dose, for instance at ozone/gelatin molar ratios between 0.1 and 0.35 the structural damage introduced by ozone oxidation of gelatin is minimal to negligible and this may facilitate the industrial utilization of ozone in the cold sterilization of gelatin as well as in its bleaching processes required for certain applications. At higher O(3)/gelatin molar ratios the gelatine damage is evident both polarimetrically as suggested by the drop of its specific optical rotation and by spectrophotometrical analyses.

  20. The use of layer by layer self-assembled coatings of hyaluronic acid and cationized gelatin to improve the biocompatibility of poly(ethylene terephthalate) artificial ligaments for reconstruction of the anterior cruciate ligament.

    PubMed

    Li, Hong; Chen, Chen; Zhang, Shurong; Jiang, Jia; Tao, Hongyue; Xu, Jialing; Sun, Jianguo; Zhong, Wei; Chen, Shiyi

    2012-11-01

    In this study layer by layer (LBL) self-assembled coatings of hyaluronic acid (HA) and cationized gelatin (CG) were used to modify polyethylene terephthalate (PET) artificial ligament grafts. Changes in the surface properties were characterized by scanning electron microscopy, attenuated total reflection Fourier transform infrared spectroscopy, energy-dispersive X-ray spectroscopy, and contact angle and biomechanical measurements. The cell compatibility of this HA-CG coating was investigated in vitro on PET films seeded with human foreskin dermal fibroblasts over 7days. The results of our in vitro studies demonstrated that the HA-CG coating significantly enhanced cell adhesion, facilitated cell growth, and suppressed the expression of inflammation-related genes relative to a pure PET graft. Furthermore, rabbit and porcine anterior cruciate ligament reconstruction models were used to evaluate the effect of this LBL coating in vivo. The animal experiment results proved that this LBL coating significantly inhibited inflammatory cell infiltration and promoted new ligament tissue regeneration among the graft fibers. In addition, the formation of type I collagen in the HA-CG coating group was much higher than in the control group. Based on these results we conclude that PET grafts coated with HA-CG have considerable potential as substitutes for ligament reconstruction.

  1. Langmuir-Blodgett films of random copolymers of fluoroalkyl(meth)acrylate and methacrylic acid: Fabrication and X-ray diffraction study

    SciTech Connect

    Safronov, V.; Feigin, L.A.; Budovskaya, L.D.; Ivanova, V.N.

    1994-12-31

    Langmuir-Blodgett films of amphiphilic fluorinated copolymers were fabricated and studied by X-ray diffraction. Although these films show poor interlayer periodicity, they possess a uniform thickness even in the case of very thin films of one bilayer (22 {angstrom}). This feature was used to obtain complex LB structures (superlattices) with alteration of copolymer and fatty acid bilayers. X-ray diffraction data proved the regular periodical organization of these structures and allowed to calculate electron density distribution across the superlattices.

  2. Biomimetic Synthesis of Gelatin Polypeptide-Assisted Noble-Metal Nanoparticles and Their Interaction Study

    NASA Astrophysics Data System (ADS)

    Liu, Ying; Liu, Xiaoheng; Wang, Xin

    2011-12-01

    Herein, the generation of gold, silver, and silver-gold (Ag-Au) bimetallic nanoparticles was carried out in collagen (gelatin) solution. It first showed that the major ingredient in gelatin polypeptide, glutamic acid, acted as reducing agent to biomimetically synthesize noble metal nanoparticles at 80°C. The size of nanoparticles can be controlled not only by the mass ratio of gelatin to gold ion but also by pH of gelatin solution. Interaction between noble-metal nanoparticles and polypeptide has been investigated by TEM, UV-visible, fluorescence spectroscopy, and HNMR. This study testified that the degradation of gelatin protein could not alter the morphology of nanoparticles, but it made nanoparticles aggregated clusters array (opposing three-dimensional α-helix folding structure) into isolated nanoparticles stabilized by gelatin residues. This is a promising merit of gelatin to apply in the synthesis of nanoparticles. Therefore, gelatin protein is an excellent template for biomimetic synthesis of noble metal/bimetallic nanoparticle growth to form nanometer-sized device.

  3. 21 CFR 522.1020 - Gelatin solution.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Gelatin solution. 522.1020 Section 522.1020 Food... Gelatin solution. (a) Specifications. It is sterile and each 100 cubic centimeters contains 8 grams of gelatin in an 0.85 percent sodium chloride solution. (b) Sponsor. See No. 000856 in § 510.600(c) of...

  4. 21 CFR 522.1020 - Gelatin solution.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Gelatin solution. 522.1020 Section 522.1020 Food... Gelatin solution. (a) Specifications. It is sterile and each 100 cubic centimeters contains 8 grams of gelatin in an 0.85 percent sodium chloride solution. (b) Sponsor. See No. 000856 in § 510.600(c) of...

  5. 21 CFR 522.1020 - Gelatin solution.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Gelatin solution. 522.1020 Section 522.1020 Food... Gelatin solution. (a) Specifications. It is sterile and each 100 cubic centimeters contains 8 grams of gelatin in an 0.85 percent sodium chloride solution. (b) Sponsor. See No. 000856 in § 510.600(c) of...

  6. 21 CFR 522.1020 - Gelatin.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Gelatin. 522.1020 Section 522.1020 Food and Drugs..., AND RELATED PRODUCTS IMPLANTATION OR INJECTABLE DOSAGE FORM NEW ANIMAL DRUGS § 522.1020 Gelatin. (a) Specifications. Each 100 milliliters contains 8 grams of gelatin in a 0.85 percent sodium chloride solution....

  7. Synthesis of three different galactose-based methacrylate monomers for the production of sugar-based polymers.

    PubMed

    Desport, Jessica S; Mantione, Daniele; Moreno, Mónica; Sardón, Haritz; Barandiaran, María J; Mecerreyes, David

    2016-09-02

    Glycopolymers, synthetic sugar-containing macromolecules, are attracting ever-increasing interest from the chemistry community. Glycidyl methacrylate (GMA) is an important building block for the synthesis of sugar based methacrylate monomers and polymers. Normally, glycidyl methacrylate shows some advantages such as reactivity against nucleophiles or milder synthetic conditions such as other reactive methacrylate monomers. However, condensation reactions of glycidyl methacrylate with for instance protected galactose monomer leads to a mixture of two products due to a strong competition between the two possible pathways: epoxide ring opening or transesterification. In this paper, we propose two alternative routes to synthesize regiospecific galactose-based methacrylate monomers using the epoxy-ring opening reaction. In the first alternative route, the protected galactose is first oxidized to the acid in order to make it more reactive against the epoxide of GMA. In the second route, the protected sugar was first treated with epichlorohydrin followed by the epoxy ring opening reaction with methacrylic acid, to create an identical analogue of the ring-opening product of GMA. These two monomers were polymerized using conventional radical polymerization and were compared to the previously known galactose-methacrylate one. The new polymers show similar thermal stability but lower glass transition temperature (Tg) with respect to the known galactose methacrylate polymer.

  8. The stabilizing effect of gelatin on dilutions of various tuberculins

    PubMed Central

    Toman, K.; Hejdová, E.; Polánsky, F.; Štěrbová, E.; Guld, J.

    1968-01-01

    Adsorption of highly diluted tuberculin to the inner surface of containers is particularly pronounced for acid-precipitated PPD, and certain such preparations are routinely issued with the non-ionic detergent Tween 80 as a stabilizing agent. It has been shown, however, that Tween 80, besides its anti-adsorptive effect, also has a depressive in vivo effect, especially on tuberculin reactions that would have been weak even for a test without Tween. The authors have shown in a previous report that gelatin (0.1%) also has an anti-adsorptive effect, without apparently modifying the reaction in vivo. In the present report, the effect of gelatin on tuberculins other than acid-precipitated PPD is examined, and the loss due to surface activity in the container is found to be considerably less, though still significant, for instance, for the International Standard of PPD of Mammalian Tuberculin. The loss is particularly pronounced, and the stabilizing effect of gelatin is particularly striking, for ampoules only partly filled (i.e., with an inner surface that is large in relation to the volume of the content). It is suggested that gelatin, or some similar substance with little or no in vivo action, might be used more readily, and for more kinds of tuberculin, than Tween 80, provided that further critical studies do not reveal any so far unknown factor. PMID:5306127

  9. Decoration of gold nanoparticles with thiolated pH-responsive polymeric (PEG-b-p(2-dimethylamio ethyl methacrylate-co-itaconic acid) shell: A novel platform for targeting of anticancer agent.

    PubMed

    Ghorbani, Marjan; Hamishehkar, Hamed

    2017-12-01

    The aim of this study was to design and develop a new pH-responsive nano-platform for controlled and targeted delivery of anticancer drugs. Engineering of pH-responsive nanocarriers was prepared via decoration of gold nanoparticles (NPs) by thiolated (methoxy-poly(ethylene glycol)-b-poly((2-dimethylamino) ethyl methacrylate-co-itaconic acid) (mPEG-b-p(DMAEMA-co-IA) copolymer and fully characterized by various techniques and subsequently used for loading and targeted delivery of anticancer agent, methotrexate (MTX). By conjugation of MTX with the amino groups of polymeric shell of gold NPs (with the high loading capacity of 31%), since MTX is also the target ligand of folate receptors, the targeted performance of NPs examined through the cell uptake study. The results indicated that MTX-loaded NPs showed 1.3 times more cell internalization than MTX free NPs. Cell cytotoxicity studies pointed out ~1.5 and 3 times higher cell cytotoxicity after 24h for MTX-loaded nanoparticles than MTX in MTT assay and cell cycle arrest experiments, respectively. Additionally, mPEG was used as the outer shell of NPs which caused the long-term dispersibility of the NPs even under high ionic strength. The in-vitro pH-triggered drug release of MTX showed that MTX released more than three times in simulated cancerous tissue (40°C, pH5.3) than physiologic condition (37°C, pH7.4) during 48h. The results of various experiments determined that the developed smart nanocarrier proposed as a promising nanocarrier for active and passive targeting of anionic anti-cancer agents such as MTX. Copyright © 2017. Published by Elsevier B.V.

  10. Projectile penetration into ballistic gelatin.

    PubMed

    Swain, M V; Kieser, D C; Shah, S; Kieser, J A

    2014-01-01

    Ballistic gelatin is frequently used as a model for soft biological tissues that experience projectile impact. In this paper we investigate the response of a number of gelatin materials to the penetration of spherical steel projectiles (7 to 11mm diameter) with a range of lower impacting velocities (<120m/s). The results of sphere penetration depth versus projectile velocity are found to be linear for all systems above a certain threshold velocity required for initiating penetration. The data for a specific material impacted with different diameter spheres were able to be condensed to a single curve when the penetration depth was normalised by the projectile diameter. When the results are compared with a number of predictive relationships available in the literature, it is found that over the range of projectiles and compositions used, the results fit a simple relationship that takes into account the projectile diameter, the threshold velocity for penetration into the gelatin and a value of the shear modulus of the gelatin estimated from the threshold velocity for penetration. The normalised depth is found to fit the elastic Froude number when this is modified to allow for a threshold impact velocity. The normalised penetration data are found to best fit this modified elastic Froude number with a slope of 1/2 instead of 1/3 as suggested by Akers and Belmonte (2006). Possible explanations for this difference are discussed. © 2013 Published by Elsevier Ltd.

  11. In situ preparation of powder and the sorption behaviors of molecularly imprinted polymers through the complexation between polymer ion of methyl methacrylate/acrylic acid and Ca++ ion.

    PubMed

    Chough, Sung Hyo; Park, Kwang Ho; Cho, Seung Jin; Park, Hye Ryoung

    2014-09-02

    Molecularly imprinted polymer (MIP) powders were prepared using a simple complexation strategy between the polymer carboxylate groups and template molecule followed by metal cation cross-linking of residual polymer carboxylates. Polymer powders were formed in situ by templating carboxylic acid containing polymers with 4-ethylaniline (4-EA), followed by addition of an aqueous CaCl2 solution. The solution remained homogeneous. The powders were prepared by precipitation by slowly adding a non-solvent, H2O, to the mixture. The resulting particles were very porous with uptake capacity that approached the theoretical value. We suggest two types of complexes are formed between the template, 4-EA, and polymer. The isolated entry type forms well defined cavities for the template with high specific selectivity, while the adjacent entry type forms wider binding sites without specific sorption for isomeric molecules. To evaluate conditions for forming materials with high affinity and selectivity, three MIPs were prepared containing 0.5, 1.0, and 1.5 equivalents of template to the base polymer. The MIP containing 0.5 eq showed higher specific selectivity to 4-EA, but the MIP containing 1.5 eq had noticeably lower selectivity. The lower selectivity is attributed to poorly formed binding sites with little selective sorption to any isomer when the higher ratio of template was used. However at the lower ratio of template the isolated entry is preferably formed to produce well defined binding cavities with higher selectivity to template.

  12. Exploiting mixtures of H2, CO2, and O2 for improved production of methacrylate precursor 2-hydroxyisobutyric acid by engineered Cupriavidus necator strains.

    PubMed

    Przybylski, Denise; Rohwerder, Thore; Dilßner, Cornelia; Maskow, Thomas; Harms, Hauke; Müller, Roland H

    2015-03-01

    Current manufacturing of most bulk chemicals through petrochemical routes considerably contributes to common concerns over the depletion of fossil carbon sources and greenhouse gas emissions. Sustainable future production of commodities thus requires the shift to renewable feedstocks in combination with established or newly developed synthesis routes. In this study, the potential of Cupriavidus necator H16 for autotrophic synthesis of the building block chemical 2-hydroxyisobutyric acid (2-HIBA) is evaluated. A novel biosynthetic pathway was implemented by heterologous expression of the 2-hydroxyisobutyryl-coenzyme A (2-HIB-CoA) mutase from Aquincola tertiaricarbonis L108, relying on a main intermediate of strain H16's C4 overflow metabolism, 3-hydroxybutyryl-CoA. The intention was to direct the latter to 2-HIBA instead or in addition to poly-3-hydroxybutyrate (PHB). Autotrophic growth and 2-HIBA (respectively, PHB) synthesis of wild-type and PHB-negative mutant strains were investigated producing maximum 2-HIBA titers of 3.2 g L(-1) and maximum specific 2-HIBA synthesis rates (q 2-HIBA) of about 16 and 175 μmol g(-1) h(-1), respectively. The obtained specific productivity was the highest reported to date for mutase-dependent 2-HIBA synthesis from heterotrophic and autotrophic substrates. Furthermore, expression of a G protein chaperone (MeaH) in addition to the 2-HIB-CoA mutase subunits yielded improved productivity. Analyzing the inhibition of growth and product synthesis due to substrate availability and product accumulation revealed a strong influence of 2-HIBA, when cells were cultivated at high titers. Nevertheless, the presented results imply that at the time the autotrophic synthesis route is superior to thus far established heterotrophic routes for production of 2-HIBA with C. necator.

  13. Photocurable bioadhesive based on lactic acid.

    PubMed

    Marques, D S; Santos, J M C; Ferreira, P; Correia, T R; Correia, I J; Gil, M H; Baptista, C M S G

    2016-01-01

    Novel photocurable and low molecular weight oligomers based on l-lactic acid with proven interest to be used as bioadhesive were successfully manufactured. Preparation of lactic acid oligomers with methacrylic end functionalizations was carried out in the absence of catalyst or solvents by self-esterification in two reaction steps: telechelic lactic acid oligomerization with OH end groups and further functionalization with methacrylic anhydride. The final adhesive composition was achieved by the addition of a reported biocompatible photoinitiator (Irgacure® 2959). Preliminary in vitro biodegradability was investigated by hydrolytic degradation in PBS (pH=7.4) at 37 °C. The adhesion performance was evaluated using glued aminated substrates (gelatine pieces) subjected to pull-to-break test. Surface energy measured by contact angles is lower than the reported values of the skin and blood. The absence of cytoxicity was evaluated using human fibroblasts. A notable antimicrobial behaviour was observed using two bacterial models (Staphylococcus aureus and Escherichia coli). The cured material exhibited a strong thrombogenic character when placed in contact with blood, which can be predicted as a haemostatic effect for bleeding control. This novel material was subjected to an extensive characterization showing great potential for bioadhesive or other biomedical applications where biodegradable and biocompatible photocurable materials are required.

  14. Recovery, viscoelastic and functional properties of Barbel skin gelatine: investigation of anti-DPP-IV and anti-prolyl endopeptidase activities of generated gelatine polypeptides.

    PubMed

    Sila, Assaâd; Martinez-Alvarez, Oscar; Haddar, Anissa; Gómez-Guillén, M Carmen; Nasri, Moncef; Montero, M Pilar; Bougatef, Ali

    2015-02-01

    The characteristics and functional properties of gelatine from freshwater fish skin (Barbus callensis) were investigated. The gelatine extraction efficiency was improved by an acid-swelling process in the presence of barbel crude acid protease extract. Barbel skin gelatine (BSG) contained 92.15% protein, 0.31% lipid and 0.72% ash. The amino acid profile of BSG showed a high percentage of imino acids. The electrophoretic profile showed that BSG is mainly composed of α- and β-components. BSG showed an excellent solubility and possessed interfacial properties, which were governed by the protein concentration. Biological activities of the hydrolysates obtained after digestion of BSG with several commercial proteases were evaluated. The results suggested that these hydrolysates are a good source of natural inhibitors of dipeptidyl peptidase-IV and prolyl endopeptidase and could potentially be used as dietary ingredients in the management of type 2-diabetes and/or neuropathological disorders. Copyright © 2014 Elsevier Ltd. All rights reserved.

  15. Precise Tuning of Facile One-Pot Gelatin Methacryloyl (GelMA) Synthesis

    PubMed Central

    Shirahama, Hitomi; Lee, Bae Hoon; Tan, Lay Poh; Cho, Nam-Joon

    2016-01-01

    Gelatin-methacryloyl (GelMA) is one of the most commonly used photopolymerizable biomaterials in bio-applications. However, GelMA synthesis remains suboptimal, as its reaction parameters have not been fully investigated. The goal of this study is to establish an optimal route for effective and controllable GelMA synthesis by systematically examining reaction parameters including carbonate-bicarbonate (CB) buffer molarity, initial pH adjustment, MAA concentration, gelatin concentration, reaction temperature, and reaction time. We employed several analytical techniques in order to determine the degree of substitution (DS) and conducted detailed structural analysis of the synthesized polymer. The results enabled us to optimize GelMA synthesis, showing the optimal conditions to balance the deprotonation of amino groups with minimizing MAA hydrolysis, which led to nearly complete substitution. The optimized conditions (low feed ratio of MAA to gelatin (0.1 mL/g), 0.25 M CB buffer at pH 9, and a gelatin concentration of 10–20%) enable a simplified reaction scheme that produces GelMA with high substitution with just one-step addition of MAA in one pot. Looking forward, these optimal conditions not only enable facile one-pot GelMA synthesis but can also guide researchers to explore the efficient, high methacrylation of other biomacromolecules. PMID:27503340

  16. Precise Tuning of Facile One-Pot Gelatin Methacryloyl (GelMA) Synthesis

    NASA Astrophysics Data System (ADS)

    Shirahama, Hitomi; Lee, Bae Hoon; Tan, Lay Poh; Cho, Nam-Joon

    2016-08-01

    Gelatin-methacryloyl (GelMA) is one of the most commonly used photopolymerizable biomaterials in bio-applications. However, GelMA synthesis remains suboptimal, as its reaction parameters have not been fully investigated. The goal of this study is to establish an optimal route for effective and controllable GelMA synthesis by systematically examining reaction parameters including carbonate-bicarbonate (CB) buffer molarity, initial pH adjustment, MAA concentration, gelatin concentration, reaction temperature, and reaction time. We employed several analytical techniques in order to determine the degree of substitution (DS) and conducted detailed structural analysis of the synthesized polymer. The results enabled us to optimize GelMA synthesis, showing the optimal conditions to balance the deprotonation of amino groups with minimizing MAA hydrolysis, which led to nearly complete substitution. The optimized conditions (low feed ratio of MAA to gelatin (0.1 mL/g), 0.25 M CB buffer at pH 9, and a gelatin concentration of 10–20%) enable a simplified reaction scheme that produces GelMA with high substitution with just one-step addition of MAA in one pot. Looking forward, these optimal conditions not only enable facile one-pot GelMA synthesis but can also guide researchers to explore the efficient, high methacrylation of other biomacromolecules.

  17. Ballistic impact of single particles into gelatin: experiments and modeling with application to transdermal pharmaceutical delivery.

    PubMed

    Guha, R A; Shear, N H; Papini, M

    2010-10-01

    The impact and penetration of high speed particles with the human skin is of interest for targeted drug delivery by transdermal powder injection. However, it is often difficult to perform penetration experiments on dermal tissue using micron scale particles. To address this, a finite element model of the impact and penetration of a 2 μm gold particle into the human dermis was developed and calibrated using experiments found in the literature. Using dimensional analysis, the model was linked to a larger scale steel ball-gelatin system in order to extract key material parameters for both systems and perform impact studies. In this manner, an elastic modulus of 2.25 MPa was found for skin, in good agreement with reported values from the literature. Further gelatin experiments were performed with steel, polymethyl methacrylate, titanium, and tungsten carbide balls in order to determine the effects of particle size and density on penetration depth. Both the finite element model and the steel-gelatin experiments were able to predict the penetration behavior that was found by other investigators in the study of the impact of typical particles used for vaccine delivery into the human dermis. It can therefore be concluded that scaled up systems utilizing ballistic gelatins can be used to investigate the performance of transdermal powder injection technology.

  18. Enhancement of periodontal tissue regeneration by locally controlled delivery of insulin-like growth factor-I from dextran-co-gelatin microspheres.

    PubMed

    Chen, Fa-ming; Zhao, Yi-min; Wu, Hong; Deng, Zhi-hong; Wang, Qin-tao; Zhou, Wei; Liu, Qing; Dong, Guang-ying; Li, Kun; Wu, Zhi-fen; Jin, Yan

    2006-08-28

    The present work focused on the design of novel hydrogel microspheres based on both dextran- and gelatin-derived biomaterials, and discussed whether locally controlled delivery of IGF-I from dextran-co-gelatin hydrogel microspheres (DG-MP) was useful for periodontal regeneration enhancement. Microspheres were synthesized when gelatin was cooperating with glycidyl methacrylate (GMA) derivatized dextrans (Dex-GMA) and the resultant DG-MP with a hydrogel character of which the cross-linking density could be controlled by the degree of substitution (DS, the number of methacrylates per 100 glucopyranose residues) of Dex-GMA. In this study, three types of DG-MP (DG-MP4.7, DG-MP6.3 and DG-MP7.8) obtained from gelatin and Dex-GMA (differing in DS: 4.7, 6.3 and 7.8 respectively) were prepared and characterized by swelling and degradation properties, drug release kinetics and biological capability in promoting tissue regeneration. By swelling in aqueous positively charged IGF-I solutions, the protein could be encapsulated in DG-MP by polyionic complexation with negatively charged acidic gelatin. No obvious influence of Dex-GMA's DS on DG-MP's configuration and size was observed, and the release and degraded properties showed no significant difference between three types of DG-MP in PBS buffer either. However, high DS of Dex-GMA could lower microsphere's swelling, prolong its degraded time and minimize IGF-I burst release markedly in dextranase-containing PBS, where IGF-I release from a slow release type of microspheres (DG-MP7.8) could be maintained more than 28 days, and an effective protein release kinetics without a significant burst but a relevantly constant release after the initial burst was achieved. IGF-I in DG-MP resulted in more new bone formation in the periodontal defects within 4 or 8 weeks than IGF-I in blood clot directly did (P < 0.01). The observed newly formation of periodontal tissues including the height and percentage of new bone and new cementum on the

  19. Characterization of methacrylated alginate and acrylic monomers as versatile SAPs.

    PubMed

    Mignon, Arn; Vermeulen, Jolien; Graulus, Geert-Jan; Martins, José; Dubruel, Peter; De Belie, Nele; Van Vlierberghe, Sandra

    2017-07-15

    Superabsorbent polymers (SAPs) based on polysaccharides, especially alginate, could offer a valuable solution in a plethora of applications going from drug delivery to self-healing concrete. This has already been proven with both calcium alginate and methacrylated alginate combined with acrylic acid. In this manuscript, the effect of varying the degree of methacrylation and use of a combination of acrylic acid and acrylamide is investigated to explore the effects on the relevant SAP characteristics. The materials showed high gel fractions and a strong swelling capacity up to 630gwater/gSAP, especially for superabsorbent polymers with a low degree of substitution. The SAPs also showed only a limited hydrolysis in aqueous and cement filtrate solutions. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. Thermomechanical behavior of amorphous tactic methacrylate polymers

    NASA Technical Reports Server (NTRS)

    Kiran, E.; Gillham, J. K.; Gipstein, E.

    1974-01-01

    Dynamic mechanical spectra of amorphous stereoregular poly(methyl methacrylate)s and poly(t-butyl methacrylate)s with assigned microtacticities are presented and discussed. An intermolecular argument is invoked to account for the higher glass transition temperature of syndiotactic vis a vis isotactic PMMA, in spite of the higher density of the latter at 30 C. An argument is presented to show that the ratio of glassy-region relaxation temperature to glass transition temperature is not only a measure of the degree of coupling of the beta and glass transition processes, but also of the degree to which intermolecular factors influence these processes. The greater extent of the low-temperature irreversibilities observed in the thermomechanical spectra of poly(t-butyl methacrylate)s is attributed to the brittle character induced by the bulky side groups which presumably weaken cohesive forces.

  1. Electro-acupuncture promotes the survival and differentiation of transplanted bone marrow mesenchymal stem cells pre-induced with neurotrophin-3 and retinoic acid in gelatin sponge scaffold after rat spinal cord transection.

    PubMed

    Zhang, Ke; Liu, Zhou; Li, Ge; Lai, Bi-Qin; Qin, Li-Na; Ding, Ying; Ruan, Jing-Wen; Zhang, Shu-Xin; Zeng, Yuan-Shan

    2014-08-01

    In the past decades, mesenchymal stem cells (MSCs) as a promising cell candidate have received the most attention in the treatment of spinal cord injury (SCI). However, due to the low survival rate and low neural differentiation rate, the grafted MSCs do not perform well as one would have expected. In the present study, we tested a combinational therapy to improve on this situation. MSCs were loaded into three-dimensional gelatin sponge (GS) scaffold. After 7 days of induction with neurotrophin-3 (NT-3) and retinoic acid (RA) in vitro, we observed a significant increase in TrkC mRNA transcription by Real-time PCR and this was confirmed by in situ hybridization. The expression of TrkC was also confirmed by Western blot and immunohistochemistry. Differentiation potential of MSCs in vitro into neuron-like cells or oligodendrocyte-like cells was further demonstrated by using immunofluorescence staining. The pre-induced MSCs seeding in GS scaffolds were then grafted into the transected rat spinal cord. One day after grafting, Governor Vessel electro-acupuncture (GV-EA) treatment was applied to rats in the NR-MSCs + EA group. At 30 days after GV-EA treatment, it found that the grafted MSCs have better survival rate and neuron-like cell differentiation compared with those without GV-EA treatment. The sustained TrkC expression in the grafted MSCs as well as increased NT-3 content in the injury/graft site by GV-EA suggests that NT-3/TrkC signaling pathway may be involved in the promoting effect. This study demonstrates that GV-EA and pre-induction with NT-3 and RA together may promote the survival and differentiation of grafted MSCs in GS scaffold in rat SCI.

  2. Fibrin glue mixed with gelatin/hyaluronic acid/chondroitin-6-sulfate tri-copolymer for articular cartilage tissue engineering: the results of real-time polymerase chain reaction.

    PubMed

    Chou, Cheng-Hung; Cheng, Winston T K; Kuo, Tzong-Fu; Sun, Jui-Sheng; Lin, Feng-Huei; Tsai, Jui-Che

    2007-09-01

    Autologous fibrin glue has been demonstrated as a potential scaffold with very good biocompatibility for neocartilage formation. However, fibrin glue has been reported not to provide enough mechanical strength, but with many growth factors to interfere the tissue growth. Gelatin/hyaluronic acid/chondroitin-6-sulfate (GHC6S) tri-copolymer sponge has been prepared as scaffold for cartilage tissue engineering and showed very good results, but problems of cell seeding and cell distribution troubled the researchers. In this study, GHC6S particles would be added into the fibrin glue to provide better mechanical strength, better cell distribution, and easier cell seeding, which would be expected to improve cartilage regeneration in vitro. Porcine cryo-precipitated fibrinogen and thrombin prepared from prothrombin activated by 10% CaCl(2) solution were used in two groups. One is the fibrin glue group in which porcine chondrocytes were mixed with thrombin-fibrinogen solution, which was then converted into fibrin glue. The other is GHC6S-fibrin glue in which GHC6S particles were added into the thrombin-fibrinogen solution with porcine chondrocytes. After culturing for 1-2 weeks, the chondrocytes cultured in GHC6S-fibrin glue showed a round shape with distinct lacuna structure and showed positive in S-100 protein immunohistochemical stain. The related gene expressions of tissue inhibitor of metalloproteinases-1, matrix metalloproteinase-2, MT1-MMP, aggrecan, decorin, type I, II, X collagen, interleukin-1 beta, transforming growth factor-beta 1 (TGF-beta1), and Fas-associating death domain were checked by real-time PCR. The results indicated that the chondrocytes cultured in GHC6S-fibrin glue would effectively promote extracellular matrix (ECM) secretion and inhibit ECM degradation. The evidence could support that GHC6S-fibrin glue would be a promising scaffold for articular cartilage tissue engineering.

  3. Optimization and physical properties of gelatin extracted from pangasius catfish (Pangasius sutchi) bone.

    PubMed

    Mahmoodani, F; Ardekani, V Sanaei; See, S F; Yusop, S M; Babji, A S

    2014-11-01

    In the present study, to establish the optimum gelatin extraction conditions from pangasius catfish (Pangasius sutchi) bone, Response Surface Methodology (RSM) with a 4-factor, 5-level Central Composite Design (CCD) was conducted. The model equation was proposed with regard to the effects of HCl concentration (%, X1), treatment time (h, X2), extraction temperature (°C, X3) and extraction time (h, X4) as independent variables on the hydroxyproline recovery (%, Y) as dependent variable. X 1 = 2.74 %, X 2 = 21.15 h, X 3 = 74.73 °C and X 4 = 5.26 h were found to be the optimum conditions to obtain the highest hydroxyproline recovery (68.75 %). The properties of optimized catfish bone gelatin were characterized by amino acid analysis, SDS-PAGE, gel strength, TPA and viscosity in comparison to bovine skin gelatin. The result of SDS-PAGE revealed that pangasius catfish bone gelatin consisted of at least 2 different polypeptides (α1 and α2 chains) and their cross-linked chains. Moreover, the pangasius catfish bone gelatin was found to contain 17.37 (g/100 g) imino acids (proline and hydroxyproline). Pangasius catfish bone gelatin also indicated physical properties comparable with that of bovine and higher than those from cold water fish gelatin. Based on the results of the present study, there is a potential for exploitation of pangasius catfish bone for gelatin production. Furthermore, RSM provided the best method for optimizing the gelatin extraction parameters.

  4. (Meth)Acrylate Vinyl Ester Hybrid Polymerizations

    PubMed Central

    Lee, TaiYeon; Cramer, Neil; Hoyle, Charles; Stansbury, Jeffrey

    2009-01-01

    In this study vinyl ester monomers were synthesized by an amine catalyzed Michael addition reaction between a multifunctional thiol and the acrylate double bond of vinyl acrylate. The copolymerization behavior of both methacrylate/vinyl ester and acrylate/vinyl ester systems was studied with near-infrared spectroscopy. In acrylate/vinyl ester systems, the acrylate groups polymerize faster than the vinyl ester groups resulting in an overall conversion of 80% for acrylate double bonds in the acrylate/vinyl ester system relative to only 50% in the bulk acrylate system. In the methacrylate/vinyl ester systems, the difference in reactivity is even more pronounced resulting in two distinguishable polymerization regimes, one dominated by methacrylate polymerization and a second dominated by vinyl ester polymerization. A faster polymerization rate and higher overall conversion of the methacrylate double bonds is thus achieved relative to polymerization of the pure methacrylate system. The methacrylate conversion in the methacrylate/vinyl ester system is near 100% compared to only ~60% in the pure methacrylate system. Utilizing hydrophilic vinyl ester and hydrophobic methacrylate monomers, polymerization-induced phase separation is observed. The phase separated domain size is on the order of ~1 μm under the polymerization conditions. The phase separated domains become larger and more distinct with slower polymerization and correspondingly increased time for diffusion. PMID:19855853

  5. Development and evaluation of a new kinetic assay for the quantitation of fibronectin gelatin-binding activity.

    PubMed

    Gelder, F B; Brown, S T; Moore, C A

    1985-10-01

    A new rapid and sensitive kinetic assay that measures the gelatin-binding activity of fibronectin has been developed. This assay is based on the rate of fibronectin-mediated aggregation of covalently coupled latex-gelatin particles. The addition of human plasma and serum resulted in aggregation rates proportional to the concentration of fibronectin in the test sample. This assay was inhibited by the addition of gelatin, demonstrating substrate specificity. This new assay requires 50 microliter of sample and can be performed within 5 minutes. Particle aggregation rates were affected by pH, heparin, and coupled gelatin concentration per milligram of latex. Maximum aggregation rates were observed at pH 8.0. Heparin was not an absolute requirement for particle aggregation but enhanced rates up to 1 U heparin/ml with little additive effect at greater concentrations. Heparin had a relatively greater effect on assays performed in acidic buffers. The concentration of gelatin per milligram of latex was rate limiting up to approximately 50 micrograms gelatin/mg latex with little change in aggregation rates at higher concentrations. Good correlation between total antigenic fibronectin (electroimmunoassay) and fibronectin gelatin-binding activity (latex-gelatin kinetic aggregation assay) was demonstrated in plasma from normal blood donors. This new assay will allow further definition of the relationship between fibronectin gelatin-binding activity and antigenic fibronectin in normal and pathophysiologic states.

  6. 40 CFR 721.10153 - Modified methyl methacrylate, 2-hydroxyethyl methacrylate polymer (generic).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...-hydroxyethyl methacrylate polymer (generic). 721.10153 Section 721.10153 Protection of Environment...-hydroxyethyl methacrylate polymer (generic). (a) Chemical substance and significant new uses subject to... methacrylate polymer (PMN P-08-6) is subject to reporting under this section for the significant new...

  7. 40 CFR 721.10153 - Modified methyl methacrylate, 2-hydroxyethyl methacrylate polymer (generic).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...-hydroxyethyl methacrylate polymer (generic). 721.10153 Section 721.10153 Protection of Environment...-hydroxyethyl methacrylate polymer (generic). (a) Chemical substance and significant new uses subject to... methacrylate polymer (PMN P-08-6) is subject to reporting under this section for the significant new...

  8. 40 CFR 721.10153 - Modified methyl methacrylate, 2-hydroxyethyl methacrylate polymer (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...-hydroxyethyl methacrylate polymer (generic). 721.10153 Section 721.10153 Protection of Environment...-hydroxyethyl methacrylate polymer (generic). (a) Chemical substance and significant new uses subject to... methacrylate polymer (PMN P-08-6) is subject to reporting under this section for the significant new uses...

  9. 40 CFR 721.9492 - Polymers of styrene, cyclohexyl methacrylate and substituted methacrylate.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Polymers of styrene, cyclohexyl... Significant New Uses for Specific Chemical Substances § 721.9492 Polymers of styrene, cyclohexyl methacrylate... generically as polymers of styrene, cyclohexyl methacrylate and substituted methacrylate (PMNs P-97-143/144...

  10. 40 CFR 721.10153 - Modified methyl methacrylate, 2-hydroxyethyl methacrylate polymer (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...-hydroxyethyl methacrylate polymer (generic). 721.10153 Section 721.10153 Protection of Environment...-hydroxyethyl methacrylate polymer (generic). (a) Chemical substance and significant new uses subject to... methacrylate polymer (PMN P-08-6) is subject to reporting under this section for the significant new uses...

  11. 40 CFR 721.10153 - Modified methyl methacrylate, 2-hydroxyethyl methacrylate polymer (generic).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...-hydroxyethyl methacrylate polymer (generic). 721.10153 Section 721.10153 Protection of Environment...-hydroxyethyl methacrylate polymer (generic). (a) Chemical substance and significant new uses subject to... methacrylate polymer (PMN P-08-6) is subject to reporting under this section for the significant new uses...

  12. Antioxidant and cryoprotective effects of Amur sturgeon skin gelatin hydrolysate in unwashed fish mince.

    PubMed

    Nikoo, Mehdi; Benjakul, Soottawat; Xu, Xueming

    2015-08-15

    Antioxidant and cryoprotective effects of Amur sturgeon skin gelatin hydrolysates prepared using different commercial proteases in unwashed fish mince were investigated. Gelatin hydrolysates prepared using either Alcalase or Flavourzyme, were effective in preventing lipid oxidation as evidenced by the lower thiobarbituric acid-reactive substances formation. Gelatin hydrolysates were able to retard protein oxidation as indicated by the retarded protein carbonyl formation and lower loss in sulfhydryl content. In the presence of gelatin hydrolysates, unwashed mince had higher transition temperature of myosin and higher enthalpy of myosin and actin as determined by differential scanning calorimetry. Based on low field proton nuclear magnetic resonance analysis, gelatin hydrolysates prevented the displacement of water molecules between the different compartments, thus stabilizing the water associated with myofibrils in unwashed mince induced by repeated freeze-thawing. Oligopeptides in gelatin hydrolysates more likely contributed to the cryoprotective effect. Thus, gelatin hydrolysate could act as both antioxidant and cryoprotectant in unwashed fish mince. Copyright © 2015 Elsevier Ltd. All rights reserved.

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

    PubMed

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

    2015-08-01

    Aligned poly lactic-co-glycolic acid (PLGA) and PLGA/gelatin nanofibrous scaffolds embedded with mesoporous silica nanoparticles (MSNPs) were fabricated using electrospinning method. The mean diameters of nanofibers were 641±24 nm for the pure PLGA scaffolds vs 418±85 nm and 267±58 nm for the PLGA/10 wt% MSNPs and the PLGA/gelatin/10 wt% MSNPs scaffolds, respectively. The contact angle measurement results (102°±6.7 for the pure PLGA scaffold vs 81°±6.8 and 18°±8.7 for the PLGA/10 wt% MSNPs and the PLGA/gelatin/10 wt% MSNPs scaffolds, respectively) revealed enhanced hydrophilicity of scaffolds upon incorporation of gelatin and MSNPs. Besides, embedding the scaffolds with MSNPs resulted in improved tensile mechanical properties. Cultivation of PC12 cells on the scaffolds demonstrated that introduction of MSNPs into PLGA and PLGA/gelatin matrices leads to the improved cell attachment and proliferation as well as long cellular processes. DAPI staining results indicated that cell proliferations on the PLGA/10 wt% MSNPs and the PLGA/gelatin/10 wt% MSNPs scaffolds were strikingly (nearly 2.5 and 3 folds, respectively) higher than that on the aligned pure PLGA scaffolds. These results suggest superior properties of silica nanoparticles-incorporated PLGA/gelatin eletrospun nanofibrous scaffolds for the stem cell culture and tissue engineering applications. Copyright © 2015 Elsevier B.V. All rights reserved.

  14. Gelatin based bio-films prepared from grey triggerfish' skin influenced by enzymatic pretreatment.

    PubMed

    Souissi, Nabil; Abdelhedi, Ola; Mbarek, Aïcha; Kammoun, Wassim; Kechaou, Hela; Nasri, Moncef

    2017-09-08

    Gelatins from grey triggerfish skin were extracted with different methods The supplementation by pepsin (PG) improved the yield of extraction when compared with untreated gelatin (UG) and acidic gelatin (AG). The outputs of gelatins AG, UG and PG, obtained respectively, with acitic acid, glycine buffer and glycine buffer added with 5U of pepsin/g of the skin beforehand treated by alkali, were 6.9%, 7.9% and 9.7%, respectively. The enzymatic treatment of the alkali-pretreated skin of grey triggerfish altered the electrophoresis profile, biophysical, gellification, rheological and thermal properties of the prepared gelatins extracted under acidic condition. However, the untreated gelatin obtained without pepsin exhibited the highest transition and enthaply temperatures. In addition, the properties of the prepared films were interconnected to their microstructure as demonstrated by scanning electron microscopy. Furthermore, films with PG and UG had a regular surface and a more condensed structure, however films prepared with AG had rougher surface. Copyright © 2017. Published by Elsevier B.V.

  15. Multilayered Magnetic Gelatin Membrane Scaffolds

    PubMed Central

    Samal, Sangram K.; Goranov, Vitaly; Dash, Mamoni; Russo, Alessandro; Shelyakova, Tatiana; Graziosi, Patrizio; Lungaro, Lisa; Riminucci, Alberto; Uhlarz, Marc; Bañobre-López, Manuel; Rivas, Jose; Herrmannsdörfer, Thomas; Rajadas, Jayakumar; De Smedt, Stefaan; Braeckmans, Kevin; Kaplan, David L.; Dediu, V. Alek

    2016-01-01

    A versatile approach for the design and fabrication of multilayer magnetic scaffolds with tunable magnetic gradients is described. Multilayer magnetic gelatin membrane scaffolds with intrinsic magnetic gradients were designed to encapsulate magnetized bioagents under an externally applied magnetic field for use in magnetic-field-assisted tissue engineering. The temperature of the individual membranes increased up to 43.7 °C under an applied oscillating magnetic field for 70 s by magnetic hyperthermia, enabling the possibility of inducing a thermal gradient inside the final 3D multilayer magnetic scaffolds. On the basis of finite element method simulations, magnetic gelatin membranes with different concentrations of magnetic nanoparticles were assembled into 3D multilayered scaffolds. A magnetic-gradient-controlled distribution of magnetically labeled stem cells was demonstrated in vitro. This magnetic biomaterial–magnetic cell strategy can be expanded to a number of different magnetic biomaterials for various tissue engineering applications. PMID:26451743

  16. Starch gelatinization in coiled heaters.

    PubMed

    Kelder, J D H; Ptasinski, K J; Kerkhof, P J A M

    2004-01-01

    A gelatinizing model food derived from a 5% w/w cross-linked waxy maize starch suspension was simulated in coiled heaters to assess the impact of centrifugal forces on flow and heat transfer. For four coil diameters (D = 0.25, 1, 2.5, and infinity m) and three flow rates (w = 0.5, 1, and 2 m/s), heat transfer, viscous development, and the severity of channeling were evaluated. Increasing curvature proved to suppress channeling as a result of more uniform heating and gelatinization. The maximum attainable viscosity was also higher, implying a lower starch consumption for a target viscosity. Higher flow rates necessitated longer heaters, and the maximum viscosity decreased. Moderate product velocities are therefore recommended.

  17. The properties of silica-gelatin composites

    NASA Astrophysics Data System (ADS)

    Stavinskaya, O. N.; Laguta, I. V.

    2010-06-01

    Silica-gelatin composites with various silica-to-gelatin ratios were obtained. The influence of high-dispersity silica on the swelling of composites in water and desorption of pyridoxine and thiamine vitamins incorporated into the material was studied. The addition of silica to gelatin was shown to increase the time of the dissolution of the materials in aqueous medium and decelerate the desorption of vitamins.

  18. Biomimetic potential of some methacrylate-based copolymers: a comparative study.

    PubMed

    Zecheru, Teodora; Filmon, Robert; Rusen, Edina; Mărculescu, Bogdan; Zerroukhi, Amar; Cincu, Corneliu; Chappard, Daniel

    2009-11-01

    Preparation of new biocompatible materials for bone recovery has consistently gained interest in the last few decades. Special attention was given to polymers that contain negatively charged groups, such as phosphate, carboxyl, and sulfonic groups toward calcification. This present paper work demonstrates that other functional groups present also potential application in bone pathology. New copolymers of 2-hydroxyethyl methacrylate with diallyldimethylammonium chloride (DADMAC), glycidyl methacrylate (GlyMA), methacrylic acid (MAA), 2-methacryloyloxymethyl acetoacetate (MOEAA), 2-methacryloyloxyethyltriethylammonium chloride (MOETAC), and tetrahydrofurfuryl methacrylate (THFMA) were obtained. The copolymers were characterized by FTIR, swelling potential, and they were submitted to in vitro tests for calcification and cytotoxicity evaluation. GlyMA and MOETAC-containing copolymers show promising results for further in vivo mineralization tests, as a potential alternative to the classical bone grafts, in bone tissue engineering.

  19. Highly Compliant Vascular Grafts with Gelatin-Sheathed Coaxially Structured Nanofibers.

    PubMed

    Nagiah, Naveen; Johnson, Richard; Anderson, Roy; Elliott, Winston; Tan, Wei

    2015-12-01

    We have developed three types of materials composed of polyurethane-gelatin, polycaprolactone-gelatin, or polylactic acid-gelatin nanofibers by coaxially electrospinning the hydrophobic core and gelatin sheath with a ratio of 1:5 at fixed concentrations. Results from attenuated total reflection-Fourier transformed infrared spectroscopy demonstrated the gelatin coating around nanofibers in all of the materials. Transmission electron microscopy images further displayed the core-sheath structures showing the core-to-sheath thickness ratio varied greatly with the highest ratio found in polyurethane-gelatin nanofibers. Scanning electron microscopy images revealed similar, uniform fibrous structures in all of the materials, which changed with genipin cross-linking due to interfiber interactions. Thermal analyses revealed varied interactions between the hydrophilic sheath and hydrophobic core among the three materials, which likely caused different core-sheath structures, and thus physicomechanical properties. The addition of gelatin around the hydrophobic polymer and their interactions led to the formation of graft scaffolds with tissue-like viscoelasticity, high compliance, excellent swelling capability, and absence of water permeability while maintaining competent tensile modulus, burst pressure, and suture retention. The hydrogel-like characteristics are advantageous for vascular grafting use, because of the capability of bypassing preclotting prior to implantation, retaining vascular fluid volume, and facilitating molecular transport across the graft wall, as shown by coculturing vascular cells sandwiched over a thick-wall scaffold. Varied core-sheath interactions within scaffolding nanofibers led to differences in graft functional properties such as water swelling ratio, compliance, and supporting growth of cocultured vascular cells. The PCL-gelatin scaffold with thick gelatin-sheathed nanofibers demonstrated a more compliant structure, elastic mechanics, and high

  20. Preservation and storage of prepared ballistic gelatine.

    PubMed

    Mattijssen, E J A T; Alberink, I; Jacobs, B; van den Boogaard, Y

    2016-02-01

    The use of ballistic gelatine, generally accepted as a human muscle tissue simulant in wound ballistic studies, might be improved by adding a preservative (Methyl 4-hydroxybenzoate) which inhibits microbial growth. This study shows that replacing a part of the gelatine powder by the preservative does not significantly alter the penetration depth of projectiles. Storing prepared blocks of ballistic gelatine over time decreased the penetration depth of projectiles. Storage of prepared gelatine for 4 week already showed a significant effect on the penetration depth of projectiles. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  1. Evaluation of alternate routes for the synthesis of methyl methacrylate

    SciTech Connect

    Spivey, J.J.; Gogate, M.R.; Zoeller, J.R.; Colberg, R.D.; Choi, G.N.

    1998-12-31

    The use of coal-derived syngas to produce high value chemicals is an important means of upgrading this resource. One example of a chemical that can be produced from coal-derived syngas is methyl methacrylate (MMA). Poly-methyl methacrylate is widely used in coatings and in various industrial molded products. The most widely practiced commercial technology for the synthesis of MMA is the acetone cyanohydrin (ACH) process. This process requires handling of large quantities of toxic hydrogen cyanide and generates one mole of ammonium bisulfate waste per mole of MMA. This bisulfate must either be regenerated or discarded, either of which substantially increases the cost. The ACH technology is thus environmentally and economically untenable for any new MMA plant expansions that would be needed to meet increasing demand. The RTI-Eastman-Bechtel research team is developing an alternative, environmentally benign route to MMA consisting of three steps; (step 1) synthesis of a propionate from ethylene, carbon monoxide, and steam, (step 2) condensation of this propionate with formaldehyde, and (step 3) esterification of resulting methacrylic acid with methanol to form MMA. This paper describes the preliminary economics of the overall process compared to other emerging processes, and focuses on step 2, including long term testing of catalysts for the condensation of propionic acid with formaldehyde to form MAA.

  2. [Gas chromatographic analysis of methyl methacrylate and methanol in its esterification mixture].

    PubMed

    Wu, C; Zeng, C

    1997-09-01

    A fast, simple and accurate gas chromatographic method is established for determining the content of methyl methacrylate (MMA) and methanol in the esterification mixture of methacrylic acid with methanol in the presence of sulfuric acid. In the measurement, polyethylene glycol-20M/sodium hydroxide was adopted as liquid phase, coated on the acid-washed 201 pink support. n-Heptane was used as the internal standard and the correction factors of MMA and methanol obtained were 1.65 and 4.10, respectively. It is significant for this method to be used to control MMA production by acetone cyanohydrin method and to improve the production technology.

  3. SYNTHESIS OF METHYL METHACRYLATE FROM COAL-DERIVED SYNGAS

    SciTech Connect

    Makarand R. Gogate; James J. Spivey; Joseph R. Zoeller; Richard D. Colberg; Gerald N. Choi; Samuel S. Tam

    1999-04-21

    Research Triangle Institute (RTI), Eastman Chemical Company, and Bechtel collectively are developing a novel three-step process for the synthesis of methyl methacrylate (MMA) from coal-derived syngas that consists of the steps of synthesis of a propionate, its condensation with formaldehyde to form methacrylic acid (MAA), and esterification of MAA with methanol to produce MMA. The research team has completed the research on the three-step methanol-based route to MMA. Under an extension to the original contract, we are currently evaluating a new DME-based process for MMA. The key research need for DME route is to develop catalysts for DME partial oxidation reactions and DME condensation reactions. Over the last quarter (January-March/99), in-situ formaldehyde generation and condensation with methyl propionate were tested over various catalysts and reaction conditions. The patent application is in preparation and the results are retained for future reports.

  4. Azulene methacrylate polymers: synthesis, electronic properties, and solar cell fabrication.

    PubMed

    Puodziukynaite, Egle; Wang, Hsin-Wei; Lawrence, Jimmy; Wise, Adam J; Russell, Thomas P; Barnes, Michael D; Emrick, Todd

    2014-08-06

    We report the synthesis of novel azulene-substituted methacrylate polymers by free radical polymerization, in which the azulene moieties represent hydrophobic dipoles strung pendant to the polymer backbone and impart unique electronic properties to the polymers. Tunable optoelectronic properties were realized by adjusting the azulene density, ranging from homopolymers (having one azulene group per repeat unit) to copolymers in which the azulene density was diluted with other pendant groups. Treating these polymers with organic acids revealed optical and excitonic behavior that depended critically on the azulene density along the polymer chain. Copolymers of azulene with zwitterionic methacrylates proved useful as cathode modification layers in bulk-heterojunction solar cells, where the relative azulene content affected the device metrics and the power conversion efficiency reached 7.9%.

  5. SYNTHESIS OF METHACRYLATES FROM COAL-DERIVED SYNGAS

    SciTech Connect

    Jang, B.W.L.; Spivey, J.J.; Gogate, M.R.; Zoeller, J.R.; Colberg, R.D.; Choi, G.N.

    1999-12-01

    Research Triangle Institute (RTI), Eastman Chemical Company, and Bechtel have developed a novel process for synthesis of methyl methacrylate (MMA) from coal-derived syngas, under a contract from the US Department of Energy/Fossil Energy Technology Center (DOE/FETC). This project has resulted in five US patents (four already published and one pending publication). It has served as the basis for the technical and economic assessment of the production of this high-volume intermediate from coal-derived synthesis gas. The three-step process consists of the synthesis of a propionate from ethylene carbonylation using coal-derived CO, condensation of the propionate with formaldehyde to form methacrylic acid (MAA); and esterification of MAA with methanol to yield MMA. The first two steps, propionate synthesis and condensation catalysis, are the key technical challenges and the focus of the research presented here.

  6. Characteristics of PLGA-gelatin complex as potential artificial nerve scaffold.

    PubMed

    Li, Xiao-Kun; Cai, Shao-Xi; Liu, Bin; Xu, Zhi-Ling; Dai, Xiao-Zhen; Ma, Kai-Wang; Lin, Shao-Qiang; Li, Shao-Qiang; Yang, Li; Sung, K L Paul; Fu, Xiao-Bing

    2007-06-15

    The segmentation lesion of peripheral nerve will seriously impair the motion and sensation of the patients, and the satisfactory recovery of segmented peripheral nerve by autograft or allograft is still a great challenge posing to the neurosurgery. Apart from autograft for nerve repair, different allograft has been studying. In this study, a scaffold fabricated with polylactic acid-co-glycolic acid (PLGA) copolymer and gelatin was evaluated to be a potential artificial nerve scaffold in vitro. The effect of different mass ratio between PLGA and gelatin upon the characteristics of PLGA-gelatin scaffolds such as microstructure, mechanical property, degradation behavior in PBS, cell adhesion property were investigated. The results showed the homogeneity and mechanical property of the scaffolds became poor with the increase of gelatin, and the rate of max water-uptake and the mass loss of scaffolds increases with the increase of gelatin, and the cells could adhere to the scaffolds. Those indicated the scaffolds fabricated by the PLGA-gelatin complex had excellent biocompatibility, suitable mechanical property and sustained-release characteristics, which would meet the requirements for artificial nerve scaffold.

  7. Effects of Hot-Pressure Extraction Time on Composition and Gelatin Properties of Chicken Bone Extracts.

    PubMed

    Yue, Jian-Ying; Wang, Jin-Zhi; Zhang, Chun-Hui; Jia, Wei; Li, Xia; Sun, Zhen

    2017-03-29

    Hot-pressure extraction was utilized in this study to extract proteins from chicken bones at 130 °C. The obtained extracts were further used to prepare gelatin gels. Results demonstrated that the extraction time can significantly affect the composition of the chicken bone extracts (P < 0.05). High-performance liquid chromatography (HPLC) analysis indicated that the protein fraction of molecular weight (MW) >30 KDa was only visible in the extracts collected between 40 and 60 min. The highest contents of hydroxyproline, imino acids, and hydrophobic amino acids were all achieved in the chicken bone extracts after 120 min of extraction, being 3.9, 7.7, and 16.0 mg/g, respectively. The prepared gelatin properties were evaluated in terms of viscosity, storage and loss modulus, stability, gel strength, and their microstructures. Results indicated that gelatins made from chicken bone extracts of 20, 40, and 60 min extraction had better properties compared to that of 90 and 120 min. Significant correlations were identified between gelatin's composition and properties (P < 0.05). The abundance of proteins with MW of <10 KDa and 10 to 30 KDa was found to be the predominant factor that can affect the gelatin's properties. This study illustrated a promising and natural way to obtain edible gelatins from chicken bones.

  8. Exposure to volatile methacrylates in dental personnel.

    PubMed

    Hagberg, Stig; Ljungkvist, Göran; Andreasson, Harriet; Karlsson, Stig; Barregård, Lars

    2005-06-01

    Dental personnel are exposed to acrylates due to the acrylic resin-based composites and bonding agents used in fillings. It is well known that these compounds can cause contact allergy in dental personnel. However, in the 1990s, reports emerged on asthma also caused by methacrylates. The main volatile acrylates in dentistry are 2-hydroxyethyl methacrylate and methyl methacrylate. The aim of this study was to quantify the exposure to these acrylates in Swedish dental personnel. We studied the exposure to 2-hydroxyethyl methacrylate and methyl methacrylate in five randomly selected public dental clinics and at the Faculty of Odontology at Göteborg University. In total, 21 whole-day and 46 task-specific short-term (1-18 min) measurements were performed. The median 8-hour time-weighted averages were 2.5 microg/m3 (dentists) and 2.9 microg/m3 (dental nurses) for 2-hydroxyethyl methacrylate, and 0.8 microg/m3 (dentists) and 0.3 microg/m3 (dental nurses) for methyl methacrylate. The maximum short-term exposure levels were 79 microg/m3 for 2-hydroxyethyl methacrylate and 15 microg/m3 for methyl methacrylate, similar in dentists and dental nurses. The observed levels are much lower than in complete denture fabrication. We found only one previous study in dentistry and it showed similar results (though it reported short-term measurements only). Irritant effects would not be expected in healthy people at these levels. Nevertheless, occupational respiratory diseases due to methacrylates may occur in dental personnel, and improvements in the handling of these chemicals in dentistry are warranted. This includes better vials for the bonding agents and avoiding evaporation from discarded materials.

  9. Sealing Effect of Cross-Linked Gelatin Glue in the Rat Lung Air Leak Model.

    PubMed

    Kawai, Norikazu; Suzuki, Shuko; Naito, Hiroshi; Kushibe, Keiji; Tojo, Takashi; Ikada, Yoshito; Taniguchi, Shigeki

    2016-07-01

    Air leak is a common problem in pulmonary surgical procedures. In this study, we evaluated the efficacy and safety of gelatin glue (cross-linked with glutaraldehyde) in a rat model of lung air leak. A model of pulmonary fistula was created in the rat lung with the use of a needle. The fistula was then sealed with either gelatin glue (group A), fibrin glue (group B), or fibrin glue with a polyglycolic acid sheet (group C). The seal breaking pressures were measured for each group, and the results were compared. To assess the biocompatibility of the gelatin glue, a model of lung damage was created with incision, and the gelatin glue was applied to seal the wound. Histologic analysis was then performed on the lung tissue. The seal breaking pressure in group A (47.88 ± 6.69 mm Hg) was significantly higher than that in group B (24.67 ± 3.24 mm Hg, p = 0.0302) or group C (28.67 ± 3.55 mm Hg, p = 0.0406). Histologically, the gelatin glue adhered firmly to the lung surface, and only localized tissue inflammation was observed. The sealing effect of gelatin glue was superior to that of fibrin glue, with or without a polyglycolic acid sheet. In addition, the gelatin glue only caused mild inflammation of the lung and was absorbed without any adverse foreign body response. These findings suggest that gelatin glue may be a therapeutically effective biomaterial for sealing lung wounds and restoring respiratory function. Copyright © 2016 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

  10. Elastic and macroporous agarose-gelatin cryogels with isotropic and anisotropic porosity for tissue engineering.

    PubMed

    Tripathi, Anuj; Kathuria, Neeraj; Kumar, Ashok

    2009-09-01

    The focus of this work was to design a macroporous scaffold with controlled porosity in isotropic and anisotropic manner for tissue-engineering applications. Agarose-gelatin scaffolds were synthesized by cryogelation method, in which agarose was used to improve the mechanical characteristics and gelatin-provided amiable property of elasticity, cell adhesion, and cell proliferation in the scaffold. Agarose-gelatin (8%) cryogels synthesized in two different solvent systems (i.e., water and 0.1% acetic acid) at subzero temperature (-12 degrees C) showed well-interconnected porous structure. The agarose-gelatin cryogel synthesized in water solvent system (WSS) showed gradient porosity with an average pore diameter of a monolith (four sections from bottom to top; height 5 mm and diameter 13 mm each) ranging from 76 to 187 microm. The monolith of agarose-gelatin synthesized in 0.1% acetic acid solvent system (0.1% ASS) did not show any remarkable difference in average pore diameter of a monolith to their whole column length as revealed by scanning electron microscopy (SEM). These cryogels swelled up to approximately 90% of their capacity within 1 min. The aggregate tensile modulus showed good elasticity of the cryogels, in which agarose-gelatin synthesized in WSS showed higher tensile modulus, that is, 380.23 +/- 63.97 kPa in comparison with agarose-gelatin synthesized in 0.1% ASS, i.e., 278.08 +/- 94.08 kPa. The unconfined fatigue observation with varying strain (10-40%) and varying frequencies (2 and 5 Hz) showed no deformation of cryogels. The fibroblast (Cos-7) cell line seeded on the scaffold displayed good cell attachment in both types of cryogels and MTT assay showed good cell compatibility and favorable conditions for cell proliferation. These results indicate that agarose-gelatin cryogels can be a promising material of choice for tissue-engineering applications.

  11. Characteristics and gel properties of gelatin from goat skin as affected by pretreatments using sodium sulfate and hydrogen peroxide.

    PubMed

    Mad-Ali, Sulaiman; Benjakul, Soottawat; Prodpran, Thummanoon; Maqsood, Sajid

    2016-04-01

    Goat skin can be used as an alternative raw material for gelatin production, in which pretreatment conditions can determine the characteristics or properties of the resulting gelatin. The present study aimed to investigate the effect of pretreatment using sodium sulfate (Na2SO4) and hydrogen peroxide (H2O2) on properties of goat skin gelatin. Pretreatment of skin using Na2SO4 (0-1 mol L(-1)) increased the yield of gelatin in a concentration-dependent manner. When skins with prior Na2SO4 treatment were bleached using H2O2 (0-2 mol L(-1)), the resulting gelatin showed higher yield and gel strength than those without prior Na2SO4 treatment. All gelatins had α-chain as a major component, followed by β-chain. The degradation induced by H2O2 was lower in gelatin with prior Na2SO4 treatment. L* values increased with increasing H2O2 concentrations (P < 0.05) due to the bleaching effect of H2O2. With Na2SO4 and H2O2 pretreatments, gelatin gel had a finer and more ordered microstructure. Gelatin had an imino acid content of 217 residues/1000 residues with gelling and melting temperature of 22.49 and 32.28 °C, respectively. The optimal pretreatment conditions for gelatin extraction from goat skin included soaking the skin in 0.75 mol L(-1) NaOH, followed by treatment using 0.75 mol L(-1) Na2SO4 and subsequent bleaching with 2 mol L(-1) H2O2. This resulted in gelatin with superior quality to the untreated counterpart. © 2015 Society of Chemical Industry.

  12. Fractal lattice of gelatin nanoglobules

    NASA Astrophysics Data System (ADS)

    Novikov, D. V.; Krasovskii, A. N.

    2012-11-01

    The globular structure of polymer coatings on a glass, which were obtained from micellar solutions of gelatin in the isooctane-water-sodium (bis-2-ethylhexyl) sulfosuccinate system, has been studied using electron microscopy. It has been shown that an increase in the average globule size is accompanied by the formation of a fractal lattice of nanoglobules and a periodic physical network of macromolecules in the coating. The stability of such system of the "liquid-in-a-solid" type is limited by the destruction of globules and the formation of a homogeneous network structure of the coating.

  13. Ultrafiltration of gelatinous cornstarch suspensions

    SciTech Connect

    Gaddis, J.L.; Amond, T.C. III; Thomas, R.L.

    1999-04-01

    It was the objective of this study to examine ultrafiltration of gelatinized starch to compare with other viscous streams and to develop a supporting data base. The objective was broadened to explain and model observations contrasted with other viscous materials. In particular, the results of ultrafiltration of starch are not consistent with diffusion-based theories of ultrafiltration; however, the resistance to flow is well modeled as a flowing filter cake. The results presented here may be useful for predicting the performance of a starch reactor wherein the goal is to convert the starch into sugars or alcohol via the action of special enzymes or hydrolysis.

  14. Phase holograms in polymethyl methacrylate

    NASA Technical Reports Server (NTRS)

    Maker, P. D.; Muller, R. E.

    1992-01-01

    A procedure is described for the fabrication of complex computer-generated phase holograms in polymethyl methacrylate (PMMA) by means of partial-exposure e-beam lithography and subsequent carefully controlled partial development. Following the development, the pattern appears (rendered in relief) in the PMMA, which then acts as the phase-delay medium. The devices fabricated were designed with 16 equal phase steps per retardation cycle, were up to 3 mm square, and consisted of up to 10 millions of 0.3-2.0-micron square pixels. Data files were up to 60 Mb-long, and the exposure times ranged to several hours. A Fresnel phase lens was fabricated with a diffraction-limited optical performance of 83-percent efficiency.

  15. Resistance of dichromated gelatin as photoresist

    NASA Astrophysics Data System (ADS)

    Lin, Pang; Yan, Yingbai; Jin, Guofan; Wu, Minxian

    1999-09-01

    Based on the photographic chemistry, chemically hardening method was selected to enhance the anti-etch capability of gelatin. With the consideration of hardener and permeating processing, formaldehyde is the most ideal option due to the smallest molecule size and covalent cross-link with gelatin. After hardened in formaldehyde, the resistance of the gelatin was obtained by etched in 1% HF solution. The result showed that anti-etch capability of the gelatin layer increased with tanning time, but the increasing rate reduced gradually and tended to saturation. Based on the experimental results, dissolving-flaking hypothesis for chemically hardening gelatin was presented. Sol-gel coatings were etched with 1% HF solution. Compared with the etching rate of gelatin layer, it showed that gelatin could be used as resist to fabricate optical elements in sol-gel coating. With the cleaving-etch method and hardening of dichromated gelatin (DCG), DCG was used as a photoresist for fabricating sol-gel optical elements. As an application, a sol-gel random phase plate was fabricated.

  16. Sealing effects of cross-linked gelatin.

    PubMed

    Suzuki, S; Ikada, Y

    2013-03-01

    Surgical sealants form gel when applied to tissues. Currently, fibrin sealant has been successfully used in many surgical fields, but it has several disadvantages, including possible virus transmission, low adhesive strength, and high cost. In this study, gelatin and glutaraldehyde (GA) solutions were chosen to demonstrate the effectiveness of cross-linked gelatin gel as sealant and barrier, both of which have long been used in medical applications. It was found that the gelatin gel prepared from 26 wt% gelatin and 1 wt% GA solutions exhibited bonding strength almost three times higher than that of fibrin glue. The bonding strength increased with the increasing gelatin and GA concentrations. When a needle hole on PTFE vascular grafts was sealed with the gelatin gel, the water-resistant pressure significantly increased upon rubbing and was twice higher than that of fibrin glue. The cytotoxicity of gelatin gel was found to be much lower than that of albumin glue prepared at the same composition as commercially available BioGlue®. The gelatin gel was found to be also effective as barrier to prevent adhesion in a rat cecum abrasion model.

  17. Self-healing gelatin ionogels.

    PubMed

    Sharma, Anshu; Rawat, Kamla; Solanki, Pratima R; Bohidar, H B

    2017-02-01

    We demonstrate room temperature (20°C) self-healing, and substantial recovery (68-96%) of gel rigidity of gelatin, a polypeptide, ionogels (made in 1-ethyl-3-methylimidazolium chloride ionic liquid (IL) solutions via thermal treatment, IL≤5% (w/v)) after they were cut using a surgical blade. The recovery process did not require any stimuli, and the complete healing under ambient condition required about 10h.The self-healing owed its origin to the reformation of network structures via imidazolium ion mediated charge quenching of deprotonated residues, and hydrophobic interaction between neighbouring alkyl tails of IL molecules. The rate of healing determined from the growth of rigidity modulus was 20±5 mPa/s independent of ionic liquid content of the gel. This was true regardless of the fact that ionogels containing more IL had a lower gel modulus due to propensity of hydrophobic linkages, but these were agile enough to recover their network structures to a higher degree during the healing process. These features indicate that the gelatin ionogel being biocompatibile, and biodegradable holds great potential for applications in the field of biomedical engineering. Copyright © 2016 Elsevier B.V. All rights reserved.

  18. Microscopic structure of gelatin coacervates.

    PubMed

    Mohanty, Biswaranjan; Bohidar, H B

    2005-07-01

    Microscopic structure of simple coacervates of gelatin having concentration approximately 130 g/l were studied at 25 degrees C by atomic force microscopy (AFM), rheology, small angle neutron scattering (SANS), UV absorption and circular dichroism (CD) techniques. The behavior of viscoelastic exponents Delta' and Delta'' of storage and loss modulii (G'(omega) approximately omega Delta', G''(omega) approximately omega Delta") revealed that, Delta' = 0.25+/-0.01 and Delta'' = 0.78+/-0.1 for coacervates. The mass fractal dimension 'd(f)' for coacervate was found to be 2.27, which attributed a compact heterogeneous network structure to the coacervates. This is supported by AFM pictures. The CD and UV absorption data indicated presence of helical structures inside the coacervates phase. SANS results showed the existence of a single length scale associated with this system identified as gelatin persistence length, zeta = 27+/-2 A. These studies indicate that the coacervate phase is a low dimensional dense heterogeneous material comprised of strongly interconnected triple helices which imparts a large storage modulus to this material.

  19. Effects of bFGF incorporated into a gelatin sheet on wound healing.

    PubMed

    Miyoshi, Michiyo; Kawazoe, Takeshi; Igawa, Hiroharu H; Tabata, Yasuhiko; Ikada, Yoshito; Suzuki, Shigehiko

    2005-01-01

    Basic fibroblast growth factor (bFGF) is well known to promote the proliferation of almost all cells associated with wound healing. However, as the activation duration of bFGF is very short in vivo, we incorporated bFGF into an acidic gelatin hydrogel and studied the sustained release of bFGF in vivo. In addition, we investigated the effects of the acidic gelatin sheet containing bFGF on wound healing. To distinguish wound contraction from neoepithelialization, we measured both the wound area and neoepithelium length. Other histological parameters such as thickness of granulation tissue and number of capillaries were also determined as indices of wound healing. Fibrous tissue was assessed using an Elastica van Gieson and Azan stain. A skin defect (1.5 x 1.5 cm) of full thickness was created on the back of each test mouse and the wound was covered with an acidic gelatin hydrogel, referred to as a gelatin sheet in this study (2 x 2 cm), with bFGF (100 microg/site) (A) or without bFGF (B). 1, 2, 3, 5, 7 and 14 days after covering, mice were killed and an enzyme-linked immunosorbent assay (ELISA) was performed to estimate the concentration of bFGF in the plasma. In another experiment, each wound was covered with (A), (B) or a hydrogel dressing (control group, C) and the wound area was measured 1 or 2 weeks postoperatively with a computer planimeter. The histological parameters, as mentioned above, were assessed using a light microscope. Sustained release of bFGF from the gelatin sheet was observed and the gelatin sheet containing bFGF promoted neoepithelialization, granulation, neovascularization and wound closure. This gelatin sheet containing bFGF was concluded to be effective for wound healing and promising for clinical use.

  20. Use and application of gelatin as potential biodegradable packaging materials for food products.

    PubMed

    Nur Hanani, Z A; Roos, Y H; Kerry, J P

    2014-11-01

    The manufacture and potential application of biodegradable films for food application has gained increased interest as alternatives to conventional food packaging polymers due to the sustainable nature associated with their availability, broad and abundant source range, compostability, environmentally-friendly image, compatibility with foodstuffs and food application, etc. Gelatin is one such material and is a unique and popularly used hydrocolloid by the food industry today due to its inherent characteristics, thereby potentially offering a wide range of further and unique industrial applications. Gelatin from different sources have different physical and chemical properties as they contain different amino acid contents which are responsible for the varying characteristics observed upon utilization in food systems and when being utilized more specifically, in the manufacture of films. Packaging films can be successfully produced from all gelatin sources and the behaviour and characteristics of gelatin-based films can be altered through the incorporation of other food ingredients to produce composite films possessing enhanced physical and mechanical properties. This review will present the current situation with respect to gelatin usage as a packaging source material and the challenges that remain in order to move the manufacture of gelatin-based films nearer to commercial reality.

  1. Extraction of high value added gelatin biopolymer from black tilapia (Oreochromis mossambicus) head bones

    SciTech Connect

    Sockalingam, K. Abdullah, H. Z.

    2015-07-22

    Black tilapia (Oreochromis mossambicus) fish head bones were evaluated for its possibilities in extracting gelatin. Head bones were subjected to pre-treatment with 3% of hydrochloric acid (HCl) for demineralization before undergoes thermal extraction process. The raw head bones were characterized via Scanning Electron Microscopy (SEM) in order to investigate the external and internal surface morphology. SEM images also reveal the presence of collagen fiber with 1 µm diameter in the head bone. The black tilapia fish head bones yields 5.75 % of gelatin in wet weight basis, indicating the possibility of this fish species as sources of gelatin. Further characterizations were done on both raw head bones and extracted gelatin through Fourier Transform Infrared Spectroscopy (FTIR) and proximate analysis. The head bones gelatin shows high protein (10.55%) and ash (3.11 %) content with low moisture. This further proves the effectiveness of demineralization and extraction method used. The black tilapia fish head bones are found to be a prospective source of gelatin with good chemical and functional properties.

  2. Effect of cationized gelatins on the paracellular transport of drugs through caco-2 cell monolayers.

    PubMed

    Seki, Toshinobu; Kanbayashi, Hiroshi; Nagao, Tomonobu; Chono, Sumio; Tabata, Yasuhiko; Morimoto, Kazuhiro

    2006-06-01

    Cationized gelatins, candidate absorption enhancers, were prepared by addition of ethylenediamine or spermine to gelatin and the effects of the resulting ethylenediaminated gelatin (EG) and sperminated gelatin (SG) on the paracellular transport of 5(6)-carboxyfluorescein (CF), FITC-dextran-4 (FD4), and insulin through caco-2 cell monolayers were examined. The Renkin function was used for characterization of the paracellular pathway and changes in the pore radius (R) and pore occupancy/length ratio (epsilon/L) calculated from the apparent permeability coefficients (P(app)) of CF and FD4 are discussed. Ethylenediaminetetraacetic acid (EDTA) increased the R of the caco-2 cell monolayer and the P(app) of all compounds examined was markedly increased by the addition of EDTA. On the other hand, EG and SG did not increase R and their enhancing effects were not as strong as those of EDTA. The increase in epsilon/L could be the enhancing mechanism for the cationized gelatins. The number of pathways for water-soluble drugs, such as CF and FD4, in the caco-2 monolayers could be increased by the addition of the cationized gelatins. The ratios of the permeability coefficients of insulin (observed/calculated based on the Renkin function) suggest that insulin undergoes enzymatic degradation during transport which is not inhibited by enhancers.

  3. Extraction of high value added gelatin biopolymer from black tilapia (Oreochromis mossambicus) head bones

    NASA Astrophysics Data System (ADS)

    Sockalingam, K.; Abdullah, H. Z.

    2015-07-01

    Black tilapia (Oreochromis mossambicus) fish head bones were evaluated for its possibilities in extracting gelatin. Head bones were subjected to pre-treatment with 3% of hydrochloric acid (HCl) for demineralization before undergoes thermal extraction process. The raw head bones were characterized via Scanning Electron Microscopy (SEM) in order to investigate the external and internal surface morphology. SEM images also reveal the presence of collagen fiber with 1 µm diameter in the head bone. The black tilapia fish head bones yields 5.75 % of gelatin in wet weight basis, indicating the possibility of this fish species as sources of gelatin. Further characterizations were done on both raw head bones and extracted gelatin through Fourier Transform Infrared Spectroscopy (FTIR) and proximate analysis. The head bones gelatin shows high protein (10.55%) and ash (3.11 %) content with low moisture. This further proves the effectiveness of demineralization and extraction method used. The black tilapia fish head bones are found to be a prospective source of gelatin with good chemical and functional properties.

  4. Electrospinning of gelatin for tissue engineering--molecular conformation as one of the overlooked problems.

    PubMed

    Sajkiewicz, P; Kołbuk, D

    2014-01-01

    Gelatin is one of the most promising materials in tissue engineering as a scaffold component. This biopolymer indicates biocompatibility and bioactivity caused by the existence of specific amino acid sequences, being preferred sites for interactions with cells, with high similarity to natural extracellular matrix. The present paper does not aspire to be a full review of electrospinning of gelatin and gelatin containing nanofibers as scaffolds in tissue engineering. It is focused on the still open question of the role of the higher order structures of gelatin in scaffold's bioactivity/functionality. Gelatin molecules can adopt various conformations depending on temperature, solvent, pH, etc. Our review indicates the potential ways for formation of α-helix conformation during electrospinning and the methods of further structure stabilization. It is intuitively expected that the native α-helix conformation appearing as a result of partial renaturation of gelatin can be beneficial from the viewpoint of bioactivity of scaffolds, providing thus a much cheaper alternative approach as opposed to expensive electrospinning of native collagen.

  5. Ultrasound initiated miniemulsion polymerization of methacrylate monomers.

    PubMed

    Teo, Boon M; Prescott, Stuart W; Ashokkumar, Muthupandian; Grieser, Franz

    2008-01-01

    The ultrasound initiated emulsion polymerization of methyl methacrylate (MMA), n-butyl methacrylate (BMA) and 2-ethylhexyl methacrylate (2EHMA) in the presence of sodium dodecylsulfate as a stabiliser produced latex particles in the size range of 70 nm to 110 nm with molecular weights of the order of 2-6 x 10(6) g mol(-1). The experimental data obtained show significant differences in the rates of polymerization of the methacrylate monomers in the order 2EHMA>BMA>MMA. The rate trend is discussed with respect to the physicochemical properties of the monomers. It is suggested from the results obtained that the mechanism involved in sonochemical formation of the latex particles is very similar to that of a conventional miniemulsion polymerization process.

  6. Interactions of fish gelatin and chitosan in uncrosslinked and crosslinked with EDC films: FT-IR study.

    PubMed

    Staroszczyk, Hanna; Sztuka, Katarzyna; Wolska, Julia; Wojtasz-Pająk, Anna; Kołodziejska, Ilona

    2014-01-03

    Films based on fish gelatin, chitosan and blend of fish gelatin and chitosan before and after cross-linking with EDC have been characterized by FT-IR spectroscopy. The FT-IR spectrum of fish gelatin film showed the characteristic amide I, amide II and amide III bands, and the FT-IR spectrum of chitosan film confirmed that the polymer was only a partially deacetylated product, and included CH3-C=O and NH2 groups, the latter both in their free -NH2 and protonated -NH3(+) form. Analysis of FT-IR spectra of two-component, fish gelatin-chitosan film revealed the formation not only of hydrogen bonds within and between chains of polymers, but also of electrostatic interactions between -COO(-) of gelatin and -NH3(+) of chitosan. Modification with EDC provided cross-linking of composites of the film. New iso-peptide bonds formed between activated carboxylic acid groups of glutamic or aspartic acid residue of gelatin and amine groups of gelatin or/and chitosan. Copyright © 2013 Elsevier B.V. All rights reserved.

  7. Effects of acetic acid and lactic acid on physicochemical characteristics of native and cross-linked wheat starches.

    PubMed

    Majzoobi, Mahsa; Beparva, Paniz

    2014-03-15

    The effects of two common organic acids; lactic and acetic acids (150 mg/kg) on physicochemical properties of native and cross-linked wheat starches were investigated prior and after gelatinization. These acids caused formation of some cracks and spots on the granules. The intrinsic viscosity of both starches decreased in the presence of the acids particularly after gelatinization. Water solubility increased while water absorption reduced after addition of the acids. The acids caused reduction in gelatinization temperature and enthalpy of gelatinization of both starches. The starch gels became softer, less cohesive, elastic and gummy when acids were added. These changes may indicate the degradation of the starch molecules by the acids. Cross-linked wheat starch was more resistant to the acids. However, both starches became more susceptible to the acids after gelatinization. The effect of lactic acid on physicochemical properties of both starches before and after gelatinization was greater than acetic acid. Copyright © 2013 Elsevier Ltd. All rights reserved.

  8. RP-HPLC method using 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate incorporated with normalization technique in principal component analysis to differentiate the bovine, porcine and fish gelatins.

    PubMed

    Azilawati, M I; Hashim, D M; Jamilah, B; Amin, I

    2015-04-01

    The amino acid compositions of bovine, porcine and fish gelatin were determined by amino acid analysis using 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate as derivatization reagent. Sixteen amino acids were identified with similar spectral chromatograms. Data pre-treatment via centering and transformation of data by normalization were performed to provide data that are more suitable for analysis and easier to be interpreted. Principal component analysis (PCA) transformed the original data matrix into a number of principal components (PCs). Three principal components (PCs) described 96.5% of the total variance, and 2 PCs (91%) explained the highest variances. The PCA model demonstrated the relationships among amino acids in the correlation loadings plot to the group of gelatins in the scores plot. Fish gelatin was correlated to threonine, serine and methionine on the positive side of PC1; bovine gelatin was correlated to the non-polar side chains amino acids that were proline, hydroxyproline, leucine, isoleucine and valine on the negative side of PC1 and porcine gelatin was correlated to the polar side chains amino acids that were aspartate, glutamic acid, lysine and tyrosine on the negative side of PC2. Verification on the database using 12 samples from commercial products gelatin-based had confirmed the grouping patterns and the variables correlations. Therefore, this quantitative method is very useful as a screening method to determine gelatin from various sources.

  9. 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.

  10. A Novel Strategy for Softening Gelatin-Bioactive-Glass Hybrids.

    PubMed

    Negahi Shirazi, Ali; Fathi, Ali; Suarez, Francia Garces; Wang, Yiwei; Maitz, Peter K; Dehghani, Fariba

    2016-01-27

    The brittle structure of polymer-bioactive-glass hybrids is a hurdle for their biomedical applications. To address this issue here, we developed a novel method to cease the overcondensation of bioactive-glass by polymer cross-linking. Here, an organosilane-functionalized gelatin methacrylate (GelMA) is covalently bonded to a bioactive-glass during the sol-gel process, and the condensation of silica networks is controlled by photo-cross-linking of GelMA. The physicochemical properties and mechanical strength of these hybrids are tunable by the incorporation of secondary cross-linking agents. These hydrogels display elastic properties with ultimate compression strain above 0.2 mm·mm(-1) and tunable compressive modulus in the range of 42-530 kPa. In addition, these hydrogels are bioactive because they promoted the alkaline phosphatase activity of bone progenitor cells. They are also well-tolerated in the mice subcutaneous model. Therefore, our method is efficient for the prevention of overcondensation and allows preparation of soft bioactive hydrogels from organic-inorganic matrices, suitable for soft and hard tissue regeneration.

  11. Microwave Drying Effects On Dichromated Gelatin Holograms

    NASA Astrophysics Data System (ADS)

    Andrade, Ana A.; Rebordao, Jose M.

    1989-05-01

    Holograms recorded in dichromated gelatin can easily be destroyed when subjected to high temperatures. In this work, a new treatment of holographic dichromated gelatin layers that improves remarkably the hologram life time under adverse thermal conditions, is presented: exposing the developed hologram to microwave radiaton. Similar holograms were subjected to microwave radiation for variable timelengths and then subjected to heating. The resultant angular and spectral bandwidths were measured after different heating time intervals. Some preliminary results will be presented. The role of water in holograms made with dicromated gelatin will be discussed, in this new context.

  12. Collection and culture techniques for gelatinous zooplankton.

    PubMed

    Raskoff, Kevin A; Sommer, Freya A; Hamner, William M; Cross, Katrina M

    2003-02-01

    Gelatinous zooplankton are the least understood of all planktonic animal groups. This is partly due to their fragility, which typically precludes the capture of intact specimens with nets or trawls. Specialized tools and techniques have been developed that allow researchers and aquarists to collect intact gelatinous animals at sea and to maintain many of these alive in the laboratory. This paper summarizes the scientific literature on the capture, collection, and culture of gelatinous zooplankton and incorporates many unpublished methods developed at the Monterey Bay Aquarium in the past 15 years.

  13. Photolithography with polymethyl methacrylate (PMMA)

    NASA Astrophysics Data System (ADS)

    Carbaugh, Daniel J.; Wright, Jason T.; Parthiban, Rajan; Rahman, Faiz

    2016-02-01

    Polymethyl methacrylate (PMMA) is widely used as an electron beam resist but is not used as a photoresist because of its insensitivity to electromagnetic radiation with wavelengths longer than about 300 nm. In this paper we describe a technique for performing conventional photolithography with high molecular weight PMMA at the widely used 365 nm i-line wavelength. The technique involves photosensitizing PMMA with Irgacure 651—a commercially available photo-initiator that can cause PMMA strands to cross-link. Optimum amount of Irgacure can produce a negative tone photoresist with adequate photosensitivity and plasma etch resistance. We describe this technique in detail with complete processing conditions and discuss the effects of varying Irgacure 651 concentration in PMMA as well as changes in UV exposure dose. We also show example structures patterned with commonly available materials and equipment. Finally, we show that it is possible to carry out gradient lithography with this approach, in order to produce structures in relief in photosensitive PMMA.

  14. Dish-like drying patterns of the water-soluble gelatin sheet wetted by an aqueous droplet.

    PubMed

    Tsuchida, Akira; Okubo, Tsuneo

    2016-04-01

    Drying dissipative patterns of the water-soluble gelatin sheet wetted by an aqueous droplet were observed as a function of time elapsed. The arrayed clusters of dishes formed at the broad ring area and grew outward toward multiple arrays with time. The drying patterns formed by the cooperative contribution of wetting, swelling, dissolving, evaporative, convectional, sedimentary and solidifying processes. Drying patterns were studied also for aqueous ethanol, aqueous NaCl solutions and dispersions of colloidal silica and poly(methyl methacrylate) spheres. The dish patterns were observed for the water-soluble substrates, for the first time, in this work.

  15. Poly(triallyl isocyanurate-co-ethylene dimethacrylate-co-alkyl methacrylate) stationary phases in the chromatographic separation of hydrophilic solutes.

    PubMed

    Lin, Cheng-Lan; Singco, Brenda; Wu, Ching-Yi; Liang, Pei-Zhu; Cheng, Yi-Jie; Huang, Hsi-Ya

    2013-01-11

    This study describes the ability of triallyl isocyanurate (TAIC)-co-methacrylate ester polymer monoliths as stationary phases for the separation of hydrophilic compounds (phenolic acids, amino acids and catecholamines) in capillary electrochromatography (CEC) and ultra high pressure liquid chromatography (UHPLC). Several TAIC-co-methacrylate ester polymer monoliths prepared by single-step in situ copolymerization of TAIC, ethylene dimethacrylate (EDMA) and 2-acrylamido-2-methylpropane sulfonic acid (AMPS), with or without alkyl methacrylates were characterized by examining the SEM image, surface area, contact angle, and the thermal decomposition temperature. Compared to the conventional methacrylate ester-based monoliths, these proposed monoliths possessed hydrophilic character thus increased wettability which improved chromatographic separation selectivity of polar phenolic acids. Among the proposed TAIC-co-methacrylate monoliths, poly(TAIC-co-EDMA-AMPS-co-stearyl methacrylate (SMA)) showed separation selectivity with an increased analyte resolution from 0.0 to 0.92 for 4-hydroxybenzoic acid and vanillic acid, which were consistently difficult to resolve in the reversed-phase chromatographic mechanism of these monoliths in aqueous mobile phases. Moreover, stable ionization efficiencies were observed when this monolith was combined with ESI-MS detector possibly because an organic solvent-rich sheath liquid was used in the CEC-MS. This study demonstrates the potentiality of novel TAIC-co-methacrylate polymer monoliths in hydrophilic solute separation either in CEC or UHPLC mode.

  16. Performance of high amylose starch-composited gelatin films influenced by gelatinization and concentration.

    PubMed

    Wang, Wenhang; Wang, Kun; Xiao, Jingdong; Liu, Yaowei; Zhao, Yana; Liu, Anjun

    2017-01-01

    In order to study the impact of starch in film performance, high amylose corn starch was composited in gelatin films under different gelatinization conditions and, in high and low concentrations (10 and 50wt.%). It was found that hot water gelatinized starch (Gel-Shw) increased film mechanical strength and was dependent upon the starch concentration. The addition of an alkali component to the starch significantly enhanced the swelling of the starch granules and expedited the gelatinization process. Incorporation of starch, especially the alkalized starch (Sha), into the gelatin films decreased film solubility which improved its water resistance and water vapor permeability (WVP). Multiple techniques (DSC, TGA, FT-IR, and XRD) were used to characterize the process and results, including the crosslinking of the dissolved starch molecules and the particles formed from gelatinized starch during retrogradation process, which played an important role in improving the thermal stability of the composited gelatin films. Overall, the starch-gelatin composition provides a potential approach to improve gelatin film performance and benefit its applications in the food industry. Copyright © 2016 Elsevier B.V. All rights reserved.

  17. 40 CFR 721.9492 - Polymers of styrene, cyclohexyl methacrylate and substituted methacrylate.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Polymers of styrene, cyclohexyl... Significant New Uses for Specific Chemical Substances § 721.9492 Polymers of styrene, cyclohexyl methacrylate...) The chemical substances identified generically as polymers of styrene, cyclohexyl methacrylate...

  18. 40 CFR 721.9492 - Polymers of styrene, cyclohexyl methacrylate and substituted methacrylate.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Polymers of styrene, cyclohexyl... Significant New Uses for Specific Chemical Substances § 721.9492 Polymers of styrene, cyclohexyl methacrylate...) The chemical substances identified generically as polymers of styrene, cyclohexyl methacrylate...

  19. 40 CFR 721.9492 - Polymers of styrene, cyclohexyl methacrylate and substituted methacrylate.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Polymers of styrene, cyclohexyl... Significant New Uses for Specific Chemical Substances § 721.9492 Polymers of styrene, cyclohexyl methacrylate...) The chemical substances identified generically as polymers of styrene, cyclohexyl methacrylate and...

  20. 40 CFR 721.9492 - Polymers of styrene, cyclohexyl methacrylate and substituted methacrylate.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Polymers of styrene, cyclohexyl... Significant New Uses for Specific Chemical Substances § 721.9492 Polymers of styrene, cyclohexyl methacrylate...) The chemical substances identified generically as polymers of styrene, cyclohexyl methacrylate and...

  1. Novel syngas-based process for methyl methacrylate

    SciTech Connect

    Gogate, M.R.; Spivey, J.J.; Zoeller, J.R.; Choi, G.N.; Tam, S.S.; Tischer, R.E.; Srivastava, R.D.

    1996-12-31

    Research Triangle Institute (RTI), Eastman Chemical Company, and Bechtel are developing a novel process for synthesis of methyl methacrylate (MMA) from coal-derived syngas, under a contract from the U.S. Department of Energy, Pittsburgh Energy Technology Center. This three-step process consists of synthesis of a propionate, its condensation with formaldehyde, and esterification of resulting methacrylic acid (MAA) with methanol to produce MMA. Eastman has focused on the research on propionate synthesis step. The resultant Mo catalysts work efficiently at much less severe conditions (170{degrees}C and 30 atm) than the conventional Ni catalysts (270{degrees}C and 180 atm). Bechtel has performed an extensive cost analysis, which shows that Eastman`s propionate synthesis process is competitive with other technologies to produce the anhydride. In the second step, RTI and Eastman have developed active and stable V-SI-P and Ta metal oxide catalysts for condensation reactions of propionates with formaldehyde. RTI has demonstrated a novel correlation among the catalyst acid-base properties, condensation reaction yield, and long-term catalyst activity. Current research focuses on enhancing the condensation reaction yields, acid-base properties, in situ condensation in a high- temperature, high-pressure (HTHP) slurry reactor, and alternate formaldehyde feedstocks. Based on Eastman and RTI laboratory reactor operating data, a cost estimate is also being developed for the integrated process.

  2. PREPARATION, DRUG RELEASE, AND CELL GROWTH INHIBITION OF A GELATIN – DOXORUBICIN CONJUGATE

    PubMed Central

    Wu, Darren C.; Cammarata, Christopher R.; Park, Hyun Joo; Rhodes, Brian T.; Ofner, Clyde M.

    2013-01-01

    Purpose To demonstrate the feasibility of a novel macromolecular delivery system for doxorubicin (DOX) which combines pH dependent DOX release with a high molecular weight and biodegradable gelatin carrier. Methods DOX was conjugated to gelatin using an acid labile hydrazone bond and a glycylglycine linker. The gelatin-doxorubicin conjugate (G-DOX) was evaluated for hydrazide and DOX content by spectrophotometry, molecular weight by HPLC-SEC, in vitro DOX release at various pH, and cell growth inhibition using EL4 mouse lymphoma and PC3 human prostate cells. Results G-DOX hydrazide and DOX content was 47% and 5-7%, respectively of theoretical gelatin carboxylic acid sites. During preparation of G-DOX, the molecular weight decreased to 22 kDa. DOX release was 48% in pH 4.8 phosphate buffer, 22% at pH 6.5, but 10% at pH 7.4. The G-DOX IC50 values in EL4 and PC3 cells were 0.26 μM and 0.77 μM, respectively; the latter value 3 times greater than that of free DOX. Conclusions A 22 kDa macromolecular DOX conjugate containing 3.4-5.0% w/w DOX has been prepared. The pH dependent drug release in combination with a biodegradable gelatin carrier offer potential therapeutic advantages of enhanced tumor cell localization and reduced systemic toxicities of the drug. PMID:23686374

  3. Efficient production of artificially designed gelatins with a Bacillus brevis system.

    PubMed

    Kajino, T; Takahashi, H; Hirai, M; Yamada, Y

    2000-01-01

    Artificially designed gelatins comprising tandemly repeated 30-amino-acid peptide units derived from human alphaI collagen were successfully produced with a Bacillus brevis system. The DNA encoding the peptide unit was synthesized by taking into consideration the codon usage of the host cells, but no clones having a tandemly repeated gene were obtained through the above-mentioned strategy. Minirepeat genes could be selected in vivo from a mixture of every possible sequence encoding an artificial gelatin by randomly ligating the mixed sequence unit and transforming it into Escherichia coli. Larger repeat genes constructed by connecting minirepeat genes obtained by in vivo selection were also stable in the expression host cells. Gelatins derived from the eight-unit and six-unit repeat genes were extracellularly produced at the level of 0.5 g/liter and easily purified by ammonium sulfate fractionation and anion-exchange chromatography. The purified artificial gelatins had the predicted N-terminal sequences and amino acid compositions and a solgel property similar to that of the native gelatin. These results suggest that the selection of a repeat unit sequence stable in an expression host is a shortcut for the efficient production of repetitive proteins and that it can conveniently be achieved by the in vivo selection method. This study revealed the possible industrial application of artificially designed repetitive proteins.

  4. Electrospun gelatin nanofibers: a facile cross-linking approach using oxidized sucrose.

    PubMed

    Jalaja, K; James, Nirmala R

    2015-02-01

    Gelatin nanofibers were fabricated via electrospinning with minimal toxicity from solvents and cross-linking agents. Electrospinning was carried out using a solvent system based on water and acetic acid (8:2, v/v). Acetic acid concentration was kept as minimum as possible to reduce the toxic effects. Electrospun gelatin nanofibers were cross-linked with oxidized sucrose. Sucrose was oxidized by periodate oxidation to introduce aldehyde functionality. Cross-linking with oxidized sucrose could be achieved without compromising the nanofibrous architecture. Cross-linked gelatin nanofibers maintained the fibrous morphology even after keeping in contact with aqueous medium. The morphology of the cross-linked nanofibrous mats was examined by scanning electron microscopy (SEM). Oxidized sucrose cross-linked gelatin nanofibers exhibited improved thermal and mechanical properties. The nanofibrous mats were evaluated for cytotoxicity and cell viability using L-929 fibroblast cells. The results confirmed that oxidized sucrose cross-linked gelatin nanofibers were non-cytotoxic towards L-929 cells with good cell viability.

  5. Gelatin coated electrodes allow prolonged bioelectronic measurements

    NASA Technical Reports Server (NTRS)

    1966-01-01

    Silver electrodes treated with an anodizing electrolyte containing gelatin are used for long term monitoring of bioelectronic potentials in humans. The electrodes do not interact with perspiration, cause skin irritation, or promote the growth of bacteria.

  6. Gelatin microcapsules for enhanced microwave tumor hyperthermia.

    PubMed

    Du, Qijun; Fu, Changhui; Tie, Jian; Liu, Tianlong; Li, Linlin; Ren, Xiangling; Huang, Zhongbing; Liu, Huiyu; Tang, Fangqiong; Li, Li; Meng, Xianwei

    2015-02-21

    Local and rapid heating by microwave (MW) irradiation is important in the clinical treatment of tumors using hyperthermia. We report here a new thermo-seed technique for the highly efficient MW irradiation ablation of tumors in vivo based on gelatin microcapsules. We achieved 100% tumor elimination in a mouse model at an ultralow power of 1.8 W without any side-effects. The results of MTT assays, a hemolysis test and the histological staining of organs indicated that the gelatin microcapsules showed excellent compatibility with the physiological environment. A possible mechanism is proposed for MW hyperthermia using gelatin microcapsules. We also used gelatin microcapsules capped with CdTe quantum dots for in vivo optical imaging. Our study suggests that these microcapsules may have potential applications in imaging-guided cancer treatment.

  7. Gelatin microcapsules for enhanced microwave tumor hyperthermia

    NASA Astrophysics Data System (ADS)

    Du, Qijun; Fu, Changhui; Tie, Jian; Liu, Tianlong; Li, Linlin; Ren, Xiangling; Huang, Zhongbing; Liu, Huiyu; Tang, Fangqiong; Li, Li; Meng, Xianwei

    2015-02-01

    Local and rapid heating by microwave (MW) irradiation is important in the clinical treatment of tumors using hyperthermia. We report here a new thermo-seed technique for the highly efficient MW irradiation ablation of tumors in vivo based on gelatin microcapsules. We achieved 100% tumor elimination in a mouse model at an ultralow power of 1.8 W without any side-effects. The results of MTT assays, a hemolysis test and the histological staining of organs indicated that the gelatin microcapsules showed excellent compatibility with the physiological environment. A possible mechanism is proposed for MW hyperthermia using gelatin microcapsules. We also used gelatin microcapsules capped with CdTe quantum dots for in vivo optical imaging. Our study suggests that these microcapsules may have potential applications in imaging-guided cancer treatment.Local and rapid heating by microwave (MW) irradiation is important in the clinical treatment of tumors using hyperthermia. We report here a new thermo-seed technique for the highly efficient MW irradiation ablation of tumors in vivo based on gelatin microcapsules. We achieved 100% tumor elimination in a mouse model at an ultralow power of 1.8 W without any side-effects. The results of MTT assays, a hemolysis test and the histological staining of organs indicated that the gelatin microcapsules showed excellent compatibility with the physiological environment. A possible mechanism is proposed for MW hyperthermia using gelatin microcapsules. We also used gelatin microcapsules capped with CdTe quantum dots for in vivo optical imaging. Our study suggests that these microcapsules may have potential applications in imaging-guided cancer treatment. Electronic supplementary information (ESI) available. See DOI: 10.1039/c4nr07104b

  8. Enzyme-gelatin electrochemical biosensors: scaling down.

    PubMed

    De Wael, Karolien; De Belder, Stijn; Pilehvar, Sanaz; Van Steenberge, Geert; Herrebout, Wouter; Heering, Hendrik A

    2012-03-15

    In this article we investigate the possibility of scaling down enzyme-gelatin modified electrodes by spin coating the enzyme-gelatin layer. Special attention is given to the electrochemical behavior of the selected enzymes inside the gelatin matrix. A glassy carbon electrode was used as a substrate to immobilize, in the first instance, horse heart cytochrome c (HHC) in a gelatin matrix. Both a drop dried and a spin coated layer was prepared. On scaling down, a transition from diffusion controlled reactions towards adsorption controlled reactions is observed. Compared to a drop dried electrode, a spin coated electrode showed a more stable electrochemical behavior. Next to HHC, we also incorporated catalase in a spin coated gelatin matrix immobilized on a glassy carbon electrode. By spincoating, highly uniform sub micrometer layers of biocompatible matrices can be constructed. A full electrochemical study and characterization of the modified surfaces has been carried out. It was clear that in the case of catalase, gluteraldehyde addition was needed to prevent leaking of the catalase from the gelatin matrix.

  9. Enzyme-Gelatin Electrochemical Biosensors: Scaling Down

    PubMed Central

    Wael, Karolien De; Belder, Stijn De; Pilehvar, Sanaz; Steenberge, Geert Van; Herrebout, Wouter; Heering, Hendrik A.

    2012-01-01

    In this article we investigate the possibility of scaling down enzyme-gelatin modified electrodes by spin coating the enzyme-gelatin layer. Special attention is given to the electrochemical behavior of the selected enzymes inside the gelatin matrix. A glassy carbon electrode was used as a substrate to immobilize, in the first instance, horse heart cytochrome c (HHC) in a gelatin matrix. Both a drop dried and a spin coated layer was prepared. On scaling down, a transition from diffusion controlled reactions towards adsorption controlled reactions is observed. Compared to a drop dried electrode, a spin coated electrode showed a more stable electrochemical behavior. Next to HHC, we also incorporated catalase in a spin coated gelatin matrix immobilized on a glassy carbon electrode. By spincoating, highly uniform sub micrometer layers of biocompatible matrices can be constructed. A full electrochemical study and characterization of the modified surfaces has been carried out. It was clear that in the case of catalase, gluteraldehyde addition was needed to prevent leaking of the catalase from the gelatin matrix. PMID:25585635

  10. Versatility of Alkyne-Modified Poly(Glycidyl Methacrylate) Layers for Click Reactions

    SciTech Connect

    Soto-Cantu, Dr. Erick; Lokitz, Bradley S; Hinestrosa Salazar, Juan Pablo; Deodhar, Chaitra; Messman, Jamie M; Ankner, John Francis; Kilbey, II, S Michael

    2011-01-01

    Functional soft interfaces are of interest for a variety of technologies. We describe three methods for preparing substrates with alkyne groups, which show versatility for 'click' chemistry reactions. Two of the methods have the same root: formation of thin, covalently attached, reactive interfacial layers of poly(glycidyl methacrylate) (PGMA) via spin coating onto silicon wafers followed by reactive modification with either propargylamine or 5-hexynoic acid. The amine or the carboxylic acid moieties react with the epoxy groups of PGMA, creating interfacial polymer layers decorated with alkyne groups. The third method consists of using copolymers comprising glycidyl methacrylate and propargyl methacrylate (pGP). The pGP copolymers are spin coated and covalently attached on silicon wafers. For each method, we investigate the factors that control film thickness and content of alkyne groups using ellipsometry, and study the nanophase structure of the films using neutron reflectometry. Azide-terminated polymers of methacrylic acid and 2-vinyl-4,4-dimethylazlactone synthesized via reversible addition-fragmentation chain transfer polymerization were attached to the alkyne-modified substrates using 'click' chemistry, and grafting densities in the range of 0.007-0.95 chains nm{sup -2} were attained. The maximum density of alkyne groups attained by functionalization of PGMA with propargylamine or 5-hexynoic acid was approximately 2 alkynes nm{sup -3}. The alkyne content obtained by the three decorating approaches was sufficiently high that it was not the limiting factor for the click reaction of azide-capped polymers.

  11. Vitamin C-enriched gelatin supplementation before intermittent activity augments collagen synthesis.

    PubMed

    Shaw, Gregory; Lee-Barthel, Ann; Ross, Megan Lr; Wang, Bing; Baar, Keith

    2017-01-01

    Musculoskeletal injuries are the most common complaint in active populations. More than 50% of all injuries in sports can be classified as sprains, strains, ruptures, or breaks of musculoskeletal tissues. Nutritional and/or exercise interventions that increase collagen synthesis and strengthen these tissues could have an important effect on injury rates. This study was designed to determine whether gelatin supplementation could increase collagen synthesis. Eight healthy male subjects completed a randomized, double-blinded, crossover-design study in which they consumed either 5 or 15 g of vitamin C-enriched gelatin or a placebo control. After the initial drink, blood was taken every 30 min to determine amino acid content in the blood. A larger blood sample was taken before and 1 h after consumption of gelatin for treatment of engineered ligaments. One hour after the initial supplement, the subjects completed 6 min of rope-skipping to stimulate collagen synthesis. This pattern of supplementation was repeated 3 times/d with ≥6 h between exercise bouts for 3 d. Blood was drawn before and 4, 24, 48, and 72 h after the first exercise bout for determination of amino-terminal propeptide of collagen I content. Supplementation with increasing amounts of gelatin increased circulating glycine, proline, hydroxyproline, and hydroxylysine, peaking 1 h after the supplement was given. Engineered ligaments treated for 6 d with serum from samples collected before or 1 h after subjects consumed a placebo or 5 or 15 g gelatin showed increased collagen content and improved mechanics. Subjects who took 15 g gelatin 1 h before exercise showed double the amino-terminal propeptide of collagen I in their blood, indicating increased collagen synthesis. These data suggest that adding gelatin to an intermittent exercise program improves collagen synthesis and could play a beneficial role in injury prevention and tissue repair. This trial was registered at the Australian New Zealand Clinical

  12. Halal authenticity of gelatin using species-specific PCR.

    PubMed

    Shabani, Hessam; Mehdizadeh, Mehrangiz; Mousavi, Seyed Mohammad; Dezfouli, Ehsan Ansari; Solgi, Tara; Khodaverdi, Mahdi; Rabiei, Maryam; Rastegar, Hossein; Alebouyeh, Mahmoud

    2015-10-01

    Consumption of food products derived from porcine sources is strictly prohibited in Islam. Gelatin, mostly derived from bovine and porcine sources, has many applications in the food and pharmaceutical industries. To ensure that food products comply with halal regulations, development of valid and reliable analytical methods is very much required. In this study, a species-specific polymerase chain reaction (PCR) assay using conserved regions of mitochondrial DNA (cytochrome b gene) was performed to evaluate the halal authenticity of gelatin. After isolation of DNA from gelatin powders with known origin, conventional PCR using species-specific primers was carried out on the extracted DNA. The amplified expected PCR products of 212 and 271 bp were observed for porcine and bovine gelatin, respectively. The sensitivity of the method was tested on binary gelatin mixtures containing 0.1%, 1%, 10%, and 100% (w/w) of porcine gelatin within bovine gelatin and vice versa. Although most of the DNA is degraded due to the severe processing steps of gelatin production, the minimum level of 0.1% w/w of both porcine and bovine gelatin was detected. Moreover, eight food products labeled as containing bovine gelatin and eight capsule shells were subjected to PCR examination. The results showed that all samples contained bovine gelatin, and the absence of porcine gelatin was verified. This method of species authenticity is very useful to verify whether gelatin and gelatin-containing food products are derived from halal ingredients. Copyright © 2015 Elsevier Ltd. All rights reserved.

  13. Enhanced Immunomodulatory Activity of Gelatin-Encapsulated Rubus coreanus Miquel Nanoparticles

    PubMed Central

    Seo, Yong Chang; Choi, Woon Yong; Lee, Choon Geun; Cha, Seon Woo; Kim, Young Ock; Kim, Jin-Chul; Drummen, Gregor P. C.; Lee, Hyeon Yong

    2011-01-01

    The aim of this work was to investigate the immunomodulatory activities of Rubus coreanus Miquel extract-loaded gelatin nanoparticles. The mean size of the produced nanoparticles was 143 ± 18 nm with a bandwidth of 76 nm in the size distribution and a maximum size of ~200 nm, which allows effective nanoparticle uptake by cells. Confocal imaging confirmed this, since the nanoparticles were internalized within 30 min and heterogeneously distributed throughout the cell. Zeta-potential measurements showed that from pH = 5 onwards, the nanoparticles were highly negatively charged, which prevents agglomeration to clusters by electrostatic repulsion. This was confirmed by TEM imaging, which showed a well dispersed colloidal solution. The encapsulation efficiency was nearly 60%, which is higher than for other components encapsulated in gelatin nanoparticles. Measurements of immune modulation in immune cells showed a significant effect by the crude extract, which was only topped by the nanoparticles containing the extract. Proliferation of B-, T- and NK cells was notably enhanced by Rubus coreanus-gelatin nanoparticles and in general ~2–3 times higher than control and on average ~2 times higher than ferulic acid. R. coreanus-gelatin nanoparticles induced cytokine secretion (IL-6 and TNF-α) from B- and T-cells on average at a ~2–3 times higher rate compared with the extract and ferulic acid. In vivo immunomodulatory activity in mice fed with R. coreanus-gelatin nanoparticles at 1 mL/g body weight showed a ~5 times higher antibody production compared to control, a ~1.3 times higher production compared to the extract only, and a ~1.6 times higher production compared to ferulic acid. Overall, our results suggest that gelatin nanoparticles represent an excellent transport vehicle for Rubus coreanus extract and extracts from other plants generally used in traditional Asian medicine. Such nanoparticles ensure a high local concentration that results in enhancement of immune

  14. Enhanced immunomodulatory activity of gelatin-encapsulated Rubus coreanus Miquel nanoparticles.

    PubMed

    Seo, Yong Chang; Choi, Woon Yong; Lee, Choon Geun; Cha, Seon Woo; Kim, Young Ock; Kim, Jin-Chul; Drummen, Gregor P C; Lee, Hyeon Yong

    2011-01-01

    The aim of this work was to investigate the immunomodulatory activities of Rubus coreanus Miquel extract-loaded gelatin nanoparticles. The mean size of the produced nanoparticles was 143 ± 18 nm with a bandwidth of 76 nm in the size distribution and a maximum size of ~200 nm, which allows effective nanoparticle uptake by cells. Confocal imaging confirmed this, since the nanoparticles were internalized within 30 min and heterogeneously distributed throughout the cell. Zeta-potential measurements showed that from pH = 5 onwards, the nanoparticles were highly negatively charged, which prevents agglomeration to clusters by electrostatic repulsion. This was confirmed by TEM imaging, which showed a well dispersed colloidal solution. The encapsulation efficiency was nearly 60%, which is higher than for other components encapsulated in gelatin nanoparticles. Measurements of immune modulation in immune cells showed a significant effect by the crude extract, which was only topped by the nanoparticles containing the extract. Proliferation of B-, T- and NK cells was notably enhanced by Rubus coreanus-gelatin nanoparticles and in general ~2-3 times higher than control and on average ~2 times higher than ferulic acid. R. coreanus-gelatin nanoparticles induced cytokine secretion (IL-6 and TNF-α) from B- and T-cells on average at a ~2-3 times higher rate compared with the extract and ferulic acid. In vivo immunomodulatory activity in mice fed with R. coreanus-gelatin nanoparticles at 1 mL/g body weight showed a ~5 times higher antibody production compared to control, a ~1.3 times higher production compared to the extract only, and a ~1.6 times higher production compared to ferulic acid. Overall, our results suggest that gelatin nanoparticles represent an excellent transport vehicle for Rubus coreanus extract and extracts from other plants generally used in traditional Asian medicine. Such nanoparticles ensure a high local concentration that results in enhancement of immune cell

  15. Chip electrophoresis of gelatin-based nanoparticles.

    PubMed

    Weiss, Victor U; Lehner, Angela; Grombe, Ringo; Marchetti-Deschmann, Martina; Allmaier, Günter

    2013-08-01

    Recently, biodegradable nanoparticles received increasing attention for pharmaceutical applications as well as applications in the food industry. With the current investigation we demonstrate chip electrophoresis of fluorescently (FL) labeled gelatin nanoparticles (gelatin NPs) on a commercially available instrument. FL labeling included a step for the removal of low molecular mass material (especially excess dye molecules). Nevertheless, for the investigated gelatin NP preparation two analyte peaks, one very homogeneous with an electrophoretic net mobility of μ = -24.6 ± 0.3 × 10(-9) m(2) /Vs at the peak apex (n = 17) and another more heterogeneous peak with μ between approximately -27.2 ± 0.2 × 10(-9) m(2) /Vs and -36.6 ± 0.2 × 10(-9) m(2) /Vs at the peak beginning and end point (n = 11, respectively) were recorded. Filtration allowed enrichment of particles in the size range of approximately 35 nm (pore size employed for concentration of gelatin NPs) to 200 nm (pore size employed during FL labeling). This corresponded to the very homogeneous peak linking it to gelatin NPs, whereas the more heterogeneous peak probably corresponds to gelatin not cross-linked to such a high degree (NP building blocks). Several further gelatin NP preparations were analyzed according to the same protocol yielding peaks with electrophoretic net mobilities between -23.3 ± 0.3 × 10(-9) m(2) /Vs and -28.9 ± 0.2 × 10(-9) m(2) /Vs at peak apexes (n = 15 and 6). Chip electrophoresis allows analyte separation in less than two minutes (including electrophoretic sample injection). Together with the high sensitivity of the FL detection - the LOD as derived for the first main peak of the applied dye from the threefold standard deviation of the background noise values 80 pM for determined separation conditions - this leads to a very promising high throughput separation technique especially for the analysis of bionanoparticles. For gelatin NP preparations, chip electrophoresis

  16. Novel poly(methyl methacrylate)-based semi-interpenetrating polyelectrolyte gels for rechargeable lithium batteries

    NASA Astrophysics Data System (ADS)

    Kalapala, Saibabu; Easteal, Allan J.

    Novel semi-interpenetrating polymer gel electrolytes designed for use in rechargeable lithium polymer batteries are synthesised from methyl methacrylate and the lithium salt of 2-acrylamido-2-methylpropanesulfonic acid (LiAMPS). The gels are made by first synthesising linear chains of poly(LiAMPS) by free radical polymerisation of LiAMPS dissolved in dimethyl acetamide (DMA) or DMA/ethylene carbonate mixtures, then co-polymerisation of methyl methacrylate and a cross-linking monomer (tetraethyleneglycol diacrylate) to form the semi-interpenetrating network. The electrical conductivity of the gels is determined as a function of LiAMPS and methyl methacrylate (MMA) concentrations, cross-link density, and solvent composition. The conductivity ( σ) is found to be in the range 0.2 ≤ σ ≤ 0.8 mS cm -1 at ambient temperature (20 ± 1 °C).

  17. Effect of different pretreatments on functional properties of African catfish (Clarias gariepinus) skin gelatin.

    PubMed

    See, S F; Ghassem, M; Mamot, S; Babji, A S

    2015-02-01

    Pretreatments with different types of alkali and acid were compared to determine their effects on gelatin extraction from African catfish (Clarias gariepinus) skin. The study was divided into three parts. In the first part, the skins were only treated with alkaline (Ca(OH)2 or NaOH) solution or pretreated with acetic acid solution. For second part, combination of alkali and acid pretreatment was carried out. For the third part, the skins were first treated with NaOH solution, followed by the treatment with acetic acid, citric acid or sulfuric acid solution. Functional properties including the yield of protein recovery, gel strength, viscosity, pH and viscoelastic properties were determined on gelatins obtained with different pretreatment conditions. Pretreatment with alkali removed noncollagenous proteins effectively, whilst acid pretreatment induced some loss of collagenous proteins. Combination of alkali and acid pretreatment not only removed the noncollagenous proteins and caused a significant amount of swelling, but also provided the proper pH condition for extraction, during which some cross-linkages could be further destroyed but with less breakage of intramolecular peptide chains. Pretreatment of catfish skins with 0.2 N NaOH followed by 0.05 M acetic acid improved yield of protein recovery, gel strength, viscosity, melting temperature and gelling temperature of gelatin extract.

  18. 21 CFR 882.5300 - Methyl methacrylate for cranioplasty.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... methacrylate for cranioplasty. (a) Identification. Methyl methacrylate for cranioplasty (skull repair) is a self-curing acrylic that a surgeon uses to repair a skull defect in a patient. At the time of...

  19. 21 CFR 882.5300 - Methyl methacrylate for cranioplasty.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... methacrylate for cranioplasty. (a) Identification. Methyl methacrylate for cranioplasty (skull repair) is a self-curing acrylic that a surgeon uses to repair a skull defect in a patient. At the time of...

  20. 21 CFR 882.5300 - Methyl methacrylate for cranioplasty.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... methacrylate for cranioplasty. (a) Identification. Methyl methacrylate for cranioplasty (skull repair) is a self-curing acrylic that a surgeon uses to repair a skull defect in a patient. At the time of...

  1. 21 CFR 882.5300 - Methyl methacrylate for cranioplasty.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... methacrylate for cranioplasty. (a) Identification. Methyl methacrylate for cranioplasty (skull repair) is a self-curing acrylic that a surgeon uses to repair a skull defect in a patient. At the time of...

  2. 21 CFR 882.5300 - Methyl methacrylate for cranioplasty.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... methacrylate for cranioplasty. (a) Identification. Methyl methacrylate for cranioplasty (skull repair) is a self-curing acrylic that a surgeon uses to repair a skull defect in a patient. At the time of...

  3. Tissue Regeneration Using Macrophage Migration Inhibitory Factor-Impregnated Gelatin Microbeads in Cutaneous Wounds

    PubMed Central

    Zhao, Yunan; Shimizu, Tadamichi; Nishihira, Jun; Koyama, Yoshikazu; Kushibiki, Toshihiro; Honda, Ayumi; Watanabe, Hirokazu; Abe, Riichiro; Tabata, Yasuhiko; Shimizu, Hiroshi

    2005-01-01

    Migration inhibitory factor (MIF) responds to tissue damage and regulates inflammatory and immunological processes. To elucidate the function of MIF in cutaneous wound healing, we analyzed MIF knockout (KO) mice. After the excision of wounds from the dorsal skin of MIF KO and wild-type (WT) mice, healing was significantly delayed in MIF KO mice compared to WT mice. Lipopolysaccharide treatment significantly increased [3H]thymidine uptake in WT mouse fibroblasts compared to MIF KO mouse fibroblasts. Furthermore, there was a significant reduction in fibroblast and keratinocyte migration observed in MIF KO mice after 1-oleoyl-2-lysophosphatidic acid treatment. We subsequently examined whether MIF-impregnated gelatin slow-release microbeads could accelerate skin wound healing. Injection of more than 1.5 μg/500 μl of MIF-impregnated gelatin microbeads around a wound edge accelerated wound healing compared to a single MIF injection without the use of microbeads. MIF-impregnated gelatin microbeads also accelerated skin wound healing in C57BL/6 mice and diabetic db/db mice. Furthermore, incorporating MIF-impregnated gelatin microbeads into an artificial dermis implanted into MIF KO mice accelerated procollagen production and capillary formation. These findings suggest that MIF is crucial in accelerating cutaneous wound healing and that MIF-impregnated gelatin microbeads represent a promising treatment to facilitate skin wound healing. PMID:16314467

  4. Bioconversion of gelatin to methane by a coculture of Clostridium collagenovorans and Methanosarcina barkeri

    SciTech Connect

    Jain, M.K.; Zeikus, J.G. )

    1989-02-01

    A simple, stable, and transferable coculture of Clostridium collagenovorans and Methanosarcina barkeri that readily degraded gelatin into methane and carbon dioxide was developed. In monoculture, C. collagenovorans fermented all of the amino acids in gelatin except proline into acetate and carbon dioxide as the main products, with hydrogen, isovalerate, and isobutyrate detected in trace amounts (<1 mM). In coculture with M. barkeri, gelatin was transformed into methane and carbon dioxide, with varying levels of intermediary acetate formed as a function of incubation time. Various complex proteinaceous polymers could be readily transformed into methane and carbon dioxide at 30 to 40{degree}C by a stable coculture which did not require exogenous growth factor additions. In addition, the coculture was readily transferable and preserved in the viable state for long periods, and methanogenesis could be initiated rapidly without the need for exogenous pH control.

  5. Quality changes of sea bass slices wrapped with gelatin film incorporated with lemongrass essential oil.

    PubMed

    Ahmad, Mehraj; Benjakul, Soottawat; Sumpavapol, Punnanee; Nirmal, Nilesh Prakash

    2012-04-16

    Microbiological, chemical and physical changes of sea bass slices wrapped with gelatin film incorporated with 25% (w/w) lemongrass essential oil (LEO) during storage of 12 days at 4 °C were investigated. Sea bass slices wrapped with LEO film had the retarded growth of lactic acid bacteria (LAB), psychrophilic bacteria and spoilage microorganisms including H₂S-producing bacteria and Enterobacteriaceae throughout storage of 12 days in comparison with the control and those wrapped with gelatin film without LEO (G film) (P<0.05). Lowered changes of colour, K value, total volatile base nitrogen (TVB) and TBARS value were also found in LEO film wrapped samples, compared with those wrapped with G film and control, respectively. Therefore, the incorporation of LEO into gelatin film could enhance the antimicrobial and antioxidative properties of the film, thereby maintaining the qualities and extending the shelf-life of the sea bass slices stored at refrigerated temperature.

  6. Production of Electrospun Fast-Dissolving Drug Delivery Systems with Therapeutic Eutectic Systems Encapsulated in Gelatin.

    PubMed

    Mano, Francisca; Martins, Marta; Sá-Nogueira, Isabel; Barreiros, Susana; Borges, João Paulo; Reis, Rui L; Duarte, Ana Rita C; Paiva, Alexandre

    2017-02-24

    Fast-dissolving delivery systems (FDDS) have received increasing attention in the last years. Oral drug delivery is still the preferred route for the administration of pharmaceutical ingredients. Nevertheless, some patients, e.g. children or elderly people, have difficulties in swallowing solid tablets. In this work, gelatin membranes were produced by electrospinning, containing an encapsulated therapeutic deep-eutectic solvent (THEDES) composed by choline chloride/mandelic acid, in a 1:2 molar ratio. A gelatin solution (30% w/v) with 2% (v/v) of THEDES was used to produce electrospun fibers and the experimental parameters were optimized. Due to the high surface area of polymer fibers, this type of construct has wide applicability. With no cytotoxicity effect, and showing a fast-dissolving release profile in PBS, the gelatin fibers with encapsulated THEDES seem to have promising applications in the development of new drug delivery systems.

  7. Genipin-modified gelatin nanocarriers as swelling controlled drug delivery system for in vitro release of cytarabine.

    PubMed

    Khan, Huda; Shukla, R N; Bajpai, A K

    2016-04-01

    The aim of the present investigation was to design biocompatible gelatin nanoparticles, capable of releasing the cytarabine drug in a controllable way by regulating the extent of swelling of nanoparticles. In order to achieve the proposed objectives, gelatin (Type A, derived from acid cured tissue) was modified by crosslinking with genipin and nanoparticles of crosslinked gelatin were prepared using single water in oil (W/O) emulsion technique. The nanoparticles were characterized by techniques like FTIR, SEM, TEM, particles size analysis, and surface potential measurements. The nanoparticle chemical architecture was found to influence drug-releasing capacity. The influence of experimental conditions such as pH and simulated physiological fluids as the release medium was also investigated on the release profiles of cytarabine. It is possible to fabricate high-performance materials, by designing of controlled size gelatin nanoparticles with good biocompatible properties along with desired drug release profiles.

  8. Characterization of sodium carboxymethylcellulose-gelatin complex coacervation by chemical analysis of the coacervate and equilibrium fluid phases.

    PubMed

    Koh, G L; Tucker, I G

    1988-05-01

    The complex coacervation of sodium carboxymethylcellulose (SCMC) and gelatin has been characterized by chemical analyses of the coacervate and equilibrium fluid phases. The phenol-sulphuric acid (for SCMC) and Lowry (for gelatin) assays were used. Chemically analysed coacervate yield was used to predict optimum coacervation conditions, which occurred at a SCMC-gelatin mixing ratio of 3:7 at pH 3.5. The effects of pH, colloid mixing ratio and total colloid concentration on coacervate yield and composition were studied. The colloid mixing ratio, at which the peak coacervate yields occurred varied with coacervation pH. Increase in the total colloid concentration suppressed coacervation, resulting in a coacervate of higher water content. A similar coacervation mechanism was seen for two viscosity grades SCMC. However, because of the different degree of substitution of these two grades the SCMC-gelatin coacervates had different SCMC contents.

  9. Gelatin- and starch-based hydrogels. Part B: In vitro mesenchymal stem cell behavior on the hydrogels.

    PubMed

    Van Nieuwenhove, Ine; Salamon, Achim; Adam, Stefanie; Dubruel, Peter; Van Vlierberghe, Sandra; Peters, Kirsten

    2017-04-01

    Tissue regeneration often occurs only to a limited extent. By providing a three-dimensional matrix serving as a surrogate extracellular matrix that promotes adult stem cell adhesion, proliferation and differentiation, scaffold-guided tissue regeneration aims at overcoming this limitation. In this study, we applied hydrogels made from crosslinkable gelatin, the hydrolyzed form of collagen, and functionalized starch which were characterized in depth and optimized as described in Van Nieuwenhove et al., 2016. "Gelatin- and Starch-Based Hydrogels. Part A: Hydrogel Development, Characterization and Coating", Carbohydrate Polymers 152:129-39. Collagen is the main structural protein in animal connective tissue and the most abundant protein in mammals. Starch is a carbohydrate consisting of a mixture of amylose and amylopectin. Hydrogels were developed with varying chemical composition (ratio of starch to gelatin applied) and different degrees of methacrylation of the applied gelatin phase. The hydrogels used exhibited no adverse effect on viability of the stem cells cultured on them. Moreover, initial cell adhesion did not differ significantly between them, while the strongest proliferation was observed on the hydrogel with the highest degree of cross-linking. On the least crosslinked and thus most flexible hydrogels, the highest degree of adipogenic differentiation was found, while osteogenic differentiation was the strongest on the most rigid, starch-blended hydrogels. Hydrogel coating with extracellular matrix compounds aggrecan or fibronectin prior to cell seeding exhibited no significant effects. Thus, gelatin-based hydrogels can be optimized regarding maximum promotion of either adipogenic or osteogenic stem cell differentiation in vitro, which makes them promising candidates for in vivo evaluation in clinical studies aiming at either soft or hard tissue regeneration.

  10. Biodegradable gelatin-based nanospheres as pH-responsive drug delivery systems

    NASA Astrophysics Data System (ADS)

    Curcio, Manuela; Altimari, Ilaria; Spizzirri, Umile Gianfranco; Cirillo, Giuseppe; Vittorio, Orazio; Puoci, Francesco; Picci, Nevio; Iemma, Francesca

    2013-04-01

    Native gelatin, N, N'-ethylenebisacrylamide, and sodium methacrylate were inserted into a spherical crosslinked structure by a solvent-free emulsion polymerization method, in which sunflower seed oil containing different amounts of lecithin was selected as continuous phase. Nanogels were characterized by morphological analysis, particle size distribution, and determination of swelling degree. Different dimensional distributions (100-500 nm) and water affinities were obtained by varying the amount of surfactant in the polymerization feed. Nanogels were non-toxic on human bone marrow mesenchymal stromal cells and enzymatically stable in the gastric tract, with weight losses ranging from 58 to 20 % in pancreatin solution. Release profiles of diclofenac sodium salt from the nanogels were evaluated at different pH and found to depend on crosslinking degree and drug-polymer interactions; while in pancreatin solution, a complete release of the drug was observed. The release mechanism and the diffusional contribution were evaluated by semiempirical equations.

  11. Intelligent core-shell nanoparticles and hollow spheres based on gelatin and PAA via template polymerization.

    PubMed

    Wang, Yansong; Zhang, Youwei; Du, Weiping; Wu, Chengxun; Zhao, Jiongxin

    2009-06-15

    PAA/gelatin nanoparticles, with interpolymer complexes of gelatin and polyacrylic acid (PAA) as the cores and gelatin as the shells, were prepared via facile polymerization of AA on gelatin template. The morphology change of the nanoparticles during the reaction was traced by a combined use of dynamic light scattering (DLS) and atomic force microscopy (AFM) techniques, which revealed a discrepancy among the structure of the nanoparticles formed at different stages of the reaction: as the reaction proceeds, nanoparticles with larger compact cores and thinner shells are produced. The resultant nanoparticles are multi-responsive. Especially, they exhibit a significant temperature-dependent size change: upon raising the temperature from 25 degrees C, the nanoparticle size decreases monotonically until reaching equilibrium at about 40 degrees C. This temperature-dependence of the nanoparticle size was found to be reversible provided the nanoparticle solution was cooled at a low temperature (4 degrees C). The thermo-sensitivity of the nanoparticles is attributed to the thermo-induced sol-gel transition of the gelatin shells. In addition, the nanoparticles were further converted to hollow spheres via successive locking the shell structure by the reaction of gelatin with cross-linker glutaraldehyde, and cavitation of the cross-linked nanoparticles by switching the medium from acidic to neutral. The cavitation process was monitored by DLS, which indicated a mass decrease and size shrinkage. AFM and transmission electron microscopy (TEM) were used to trace the morphology change of the nanoparticles during the cavitation. The hollow structure was confirmed by TEM observation.

  12. Reflection silver-halide gelatin holograms

    NASA Astrophysics Data System (ADS)

    Usanov, Yuri E.; Vavilova, Ye. A.; Kosobokova, N. L.; Shevtsov, Michail K.

    1991-02-01

    A new principle of reflection silverhalide gelatin (SHG) holograms generation is presented. The formation mechanism of the micro-cavity structure of holographic gratings is investigated. Based on the principle discussed here three methods of processing are suggested for making highly efficient SHG reflection holograms in the blue the green and the red regions of spectra with properties similar to those of conventional dichromated gelatin (DCG) holograms. 2. SHG HOLOGRAMS AND ANALYSIS OF THE PRINCIPAL OF THEIR FABRICATION Optical properties of DCG holograms and high light sensitivity of silver halide materials in the whole visible spectrum range can be combined in SHG holograms in which light field interference pattern recording is realized on silver halide grains while the light diffraction during the reconstruction takes place on a gelatin layer similar to DCG layer having a refractive index modulation. There exist a number of methods for transforming a ''silver'' structure into refracted index modulation structure. They are based on selective hardening of silver-halide layer gelatin. According to Pennington et. al. [1] selective hardening takes place as a result of the effect of laser or UV light on a silver halide developed fixed bleached and ammonium dichromate sensitized. A gelatin in isophase grating planes is hardened to a less degree that between planes due to high adsorption of a halide silver. After the removal of halide silver from the layer during the next fixing process

  13. Reactive compatibilization of PBT/ABS blends by methyl methacrylate, glycidyl methacrylate, ethyl acrylate terpolymers

    NASA Astrophysics Data System (ADS)

    Hale, Wesley Raymond

    The impact resistance of poly(butylene terephthalate), PBT, has been improved by blending with acrylonitrile-butadiene-styrene terpolymers, ABS, as a minor dispersed phase; however, extensive coarsening of the dispersed phase in the blends occurs under certain heat fabrication conditions. The incorporation of certain reactive polymers (compatibilizers) that are miscible with the styrene/acrylonitrile (SAN) matrix of ABS should result in more stable morphologies. Terpolymers of methyl methacrylate, glycidyl methacrylate (GMA), ethyl acrylate, MGE, are effective as reactive compatibilizers for blends of PBT with SAN and ABS materials. The epoxide groups of MGE react with the carboxyl endgroups of PBT to form a MGE-g-PBT graft copolymer at the PBT/SAN interface to provide improved SAN or ABS dispersion, morphological stability, and a broadening of the melt processing window. Additionally, compatibilization produces large improvements in the low temperature fracture toughness of PBT/ABS blends; however, the toughness depends on the order of mixing blend components due to crosslinking reactions involving the epoxide groups of MGE catalyzed by residual acids present in some emulsion-made ABS materials. The PBT, ABS, and MGE type, content, and composition have been examined to evaluate their effects on the mechanical and morphological properties of PBT/ABS blends. Additionally, the effects of different processing conditions have been examined. High PBT melt viscosity is desirable for improving ABS dispersion and low temperature toughness of the blends. Generally, ABS materials with a high rubber content and low melt viscosity are desirable for toughening PBT. Moderate amounts of GMA in the blend were found to significantly improve blend properties. Melt blending can be performed using a variety of equipment; however, a co-rotating intermeshing twin screw extruder is the most effective for producing blends with excellent properties. The fracture properties of PBT

  14. GELATIN CARRIERS FOR DRUG AND CELL DELIVERY IN TISSUE ENGINEERING

    PubMed Central

    Santoro, Marco; Tatara, Alexander M.; Mikos, Antonios G.

    2014-01-01

    The ability of gelatin to form complexes with different drugs has been investigated for controlled release applications. Gelatin parameters, such as crosslinking density and isoelectric point, have been tuned in order to optimize gelatin degradation and drug delivery kinetics. In recent years, focus has shifted away from the use of gelatin in isolation towards the modification of gelatin with functional groups and the fabrication of material composites with embedded gelatin carriers. In this review, we highlight some of the latest work being performed in these areas and comment on trends in the field. Specifically, we discuss gelatin modifications for immune system evasion, drug stabilization, and targeted delivery, as well as gelatin composite systems based on ceramics, naturally-occurring polymers, and synthetic polymers. PMID:24746627

  15. In vitro evaluation of electrospun gelatin-glutaraldehyde nanofibers

    NASA Astrophysics Data System (ADS)

    Zhan, Jianchao; Morsi, Yosry; Ei-Hamshary, Hany; Al-Deyab, Salem S.; Mo, Xiumei

    2016-03-01

    The gelatin-glutaraldehyde (gelatin-GA) nanofibers were electrospun in order to overcome the defects of ex-situ crosslinking process such as complex process, destruction of fiber morphology and decrease of porosity. The morphological structure, porosity, thermal property, moisture absorption and moisture retention performance, hydrolytic resistance, mechanical property and biocompatibility of nanofiber scaffolds were tested and characterized. The gelatin-GA nanofiber has nice uniform diameter and more than 80% porosity. The hydrolytic resistance and mechanical property of the gelatin-GA nanofiber scaffolds are greatly improved compared with that of gelatin nanofibers. The contact angle, moisture absorption, hydrolysis resistance, thermal resistance and mechanical property of gelatin-GA nanofiber scaffolds could be adjustable by varying the gelatin solution concentration and GA content. The gelatin-GA nanofibers had excellent properties, which are expected to be an ideal scaffold for biomedical and tissue engineering applications.

  16. Methacrylate Polymer Monoliths for Separation Applications

    PubMed Central

    Groarke, Robert J.; Brabazon, Dermot

    2016-01-01

    This review summarizes the development of methacrylate-based polymer monoliths for separation science applications. An introduction to monoliths is presented, followed by the preparation methods and characteristics specific to methacrylate monoliths. Both traditional chemical based syntheses and emerging additive manufacturing methods are presented along with an analysis of the different types of functional groups, which have been utilized with methacrylate monoliths. The role of methacrylate based porous materials in separation science in industrially important chemical and biological separations are discussed, with particular attention given to the most recent developments and challenges associated with these materials. While these monoliths have been shown to be useful for a wide variety of applications, there is still scope for exerting better control over the porous architectures and chemistries obtained from the different fabrication routes. Conclusions regarding this previous work are drawn and an outlook towards future challenges and potential developments in this vibrant research area are presented. Discussed in particular are the potential of additive manufacturing for the preparation of monolithic structures with pre-defined multi-scale porous morphologies and for the optimization of surface reactive chemistries. PMID:28773570

  17. Synthesis of acrylates and Methacrylates from Coal-Derived Syngas

    SciTech Connect

    1997-05-12

    Research Triangle Institute (RTI), Eastman Chemical Company, and Bechtel collectively are developing a novel process for the synthesis of methyl methacrylate (MMA) from coal-derived syngas, under a contract from the U.S. Department of Energy, Federal Energy Technology Center. This three-step process consists of synthesis of a propionate, its condensation with formaldehyde, and esterification of resulting methacrylic acid (MAA) with methanol to produce MMA. Eastman has focused on the propionate synthesis step. The resultant Mo catalysts work efficiently at much less severe conditions (170{degrees}C and 30 atm) than the conventional Ni catalysts (270{degrees} C and 180 atm). Bechtel has performed an extensive cost analysis which shows that Eastman`s propionate synthesis step is competitive with other technologies to produce the anhydride. Eastman and Bechtel have also compared the RTI- Eastman-Bechtel three-step methanol route to five other process routes to MMA. The results show that the product MMA can be produced at 520/lb, for a 250 Mlb/year MMA plant, and this product cost is competitive to all other process routes to MMA, except propyne carbonylation. In the second step, RTI and Eastman have developed active and stable V-SI-P tertiary metal oxide catalysts, Nb/Si0{sub 2}, and Ta/Si0{sub 2} catalysts for condensation of propionic anhydride or propionic acid with formaldehyde. RTI has demonstrated a novel correlation among the catalyst acid-base properties, condensation reaction yield, and long-term catalyst performance. Eastman and Bechtel have used the RTI experimental results of a 20 percent Nb/Si0{sub 2} catalyst, in terms of reactant conversions, MAA selectivities, and MAA yield, for their economic analysis. Recent research focuses on enhancing the condensation reaction yields, a better understanding of the acid-base property correlation and enhancing the catalyst lifetime.

  18. Solute solvent interaction in methyl methacrylate and 2-hydroxyethyl methacrylate monomers solutions

    NASA Astrophysics Data System (ADS)

    Al-ghamdi, Attieh A.; Bahattab, M. A.; Farhoud, M.; Al-Dossary, Mishal; Al-Enizi, Abdullah; Al-Deyab, S. S.

    2006-11-01

    Solute-solvent interactions are studied using induced birefringence measurements in monomers solutions of methyl methacrylate (MMA) and 2-hydroxyethyl methacrylate (HEMA), dissolved in ethanol, acetone, ethyl acetate, tetrahydrofuran and dimethyl sulfoxide, over a broad range of concentrations. The data are combined with refractive index and density to calculate the electric, optical and molar Kerr constants. All related microscopic parameters concerning the molecular structure such as nonlinear Kerr constants, anisotropic factors, and optical anisotropy have been calculated.

  19. Understanding starch gelatinization: The phase diagram approach.

    PubMed

    Carlstedt, Jonas; Wojtasz, Joanna; Fyhr, Peter; Kocherbitov, Vitaly

    2015-09-20

    By constructing a detailed phase diagram for the potato starch-water system based on data from optical microscopy, synchrotron X-ray scattering and differential scanning calorimetry, we show that gelatinization can be interpreted in analogy with a eutectic transition. The phase rule explains why the temperature of the gelatinization transition (G) is independent on water content. Furthermore, the melting (M1) endotherm observed in DSC represents a liquidus line; the temperature for this event increases with increasing starch concentration. Both the lamellar spacing and the inter-helix distance were observed to decrease with increasing starch content for starch concentrations between approximately 65 wt% and 75 wt%, while the inter-helix distance continued decreasing upon further dehydration. Understanding starch gelatinization has been a longstanding challenge. The novel approach presented here shows interpretation of this phenomenon from a phase equilibria perspective.

  20. CEC separation of heterocyclic amines using methacrylate monolithic columns.

    PubMed

    Barceló-Barrachina, Elena; Moyano, Encarnación; Puignou, Lluís; Galceran, Maria Teresa

    2007-06-01

    Two methacrylate-based monolithic columns, one with a negatively charged group (sulfonic group) and another with a new monomer N,N-dimethylamino ethyl acrylate (DMAEA), were prepared and tested for the separation of basic compounds by CEC. This new monolithic stationary phase was prepared by the in situ polymerization of DMAEA with butyl methacrylate and ethylene dimethacrylate, using a ternary porogenic solvent consisting of water, 1-propanol and 1,4-butanediol. The performance of this column was evaluated by means of the analysis of a family of heterocyclic amines. Separation conditions such as pH, amount of organic modifier, ionic strength and elution mode (normal or counterdirectional flow) were studied. At the optimal running electrolyte composition, and using the counterdirectional mode, symmetrical electrochromatographic peaks were obtained, with the number of theoretical plates up to 30,000 and a good resolution between closely related peaks. The 2-acrylamido-2-methyl-1-propane-sulfonic acid column was used for CEC-MS, taking advantage of the compatibility of its elution mode (normal flow) with the MS coupling.

  1. The biological properties of a novel ethyl methacrylate resin.

    PubMed

    Suzuki, T; Jinno, S; Hattori, N; Okeya, H; Ishikawa, A; Deguchi, M; Ohno, Y; Kawai, T; Noguchi, T

    2006-01-01

    A novel ethyl methacrylate (EMA) resin was developed to overcome the tissue, organ and systemic damage associated with the residual monomer of conventional methyl methacrylate (MMA) resin bone cement. EMA resin is a chemical/ photopolymerizable material and is easy to handle during clinical procedures. The biocompatibility of EMA was evaluated in accordance with ISO10993-6. No inflammatory response was observed 1 and 9 weeks after implantation in the dorsal subcutaneous tissue of ddY mice. EMA resin also demonstrated better biocompatibility when compared with conventional bone cements. Poly-L-lactic acid (PLLA) was used as a carrier for bone morphogenetic protein (BMP) and added to the EMA slurry. The EMA-PLLA composite membrane was sticky and BMP readily adhered to its surface. The EMA-PLLA-BMP composite membrane induced new bone formation, the new bone growing in the shape of the EMA in the thigh muscle pouch of ddY mice. This novel EMA resin has many potential clinical applications.

  2. Synthesis of Methyl Methacrylate from Coal-Derived Syngas

    SciTech Connect

    Gerald N. Choi; James J. Spivey; Jospeh R. Zoeller; Makarand R. Gogate; Richard D. Colberg; Samuel S. Tam

    1998-04-17

    Research Triangle Institute (RTI), Eastman Chemical Company, and Bechtel collectively are developing a novel three-step process for the synthesis of methyl methacrylate (MMA) from coal-derived syngas that consists of the steps of synthesis of a propionate, its condensation with formaldehyde to form methacrylic acid (MAA), and esterification of MAA with methanol to produce MMA. RTI has completed the research on the three-step methanol-based route to MMA. Under an extension to the original contract, RTI is currently evaluating a new DME-based process for MMA. The key research need for DME route is to develop catalysts for DME partial oxidation reactions and DME condensation reactions. Over the last month, RTI has finalized the design of a fixed-bed microreactor system for DME partial oxidation reactions. RTI incorporated some design changes to the feed blending system, so as to be able to blend varying proportions of DME and oxygen. RTI has also examined the flammability limits of DME-air mixtures. Since the lower flammability limit of DME in air is 3.6 volume percent, RTI will use a nominal feed composition of 1.6 percent in air, which is less than half the lower explosion limit for DME-air mixtures. This nominal feed composition is thus considered operationally safe, for DME partial oxidation reactions. RTI is also currently developing an analytical system for DME partial oxidation reaction system.

  3. Improved functionalization of electrospun PLLA/gelatin scaffold by alternate soaking method for bone tissue engineering

    NASA Astrophysics Data System (ADS)

    Jaiswal, Amit K.; Kadam, Sachin S.; Soni, Vivek P.; Bellare, Jayesh R.

    2013-03-01

    Biomimetic biomaterials are widely being explored as scaffold for bone regeneration. In this study, we prepared poly-L-lactic acid/hydroxyapatite (PLLA/HA) and poly-L-lactic acid/gelatin/hydroxyapatite (PLLA/Gel/HA) scaffold by electrospinning of poly-L-lactic acid (PLLA) and a blend of poly-L-lactic acid/gelatin (PLLA/Gel) followed by hydroxyapatite (HA) mineralization via alternate soaking in calcium and phosphate (Ca-P) solutions. HA growth on scaffold after each soaking cycle was confirmed by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The functional groups (COOsbnd and sbnd NH2) of gelatin in the PLLA/Gel scaffold facilitated the surface nucleation of HA as compared to the PLLA scaffold. Leaching study showed HA in PLLA/Gel/HA scaffold acts as binder of gelatin and eliminates use of toxic crosslinking agents. In vitro cell attachment on these scaffolds was assessed by using human osteosarcoma cells (MG-63). Cell proliferation on scaffolds was examined by MTT assay. MTT results clearly indicated that mineralized scaffolds did not inhibit the eventual cell proliferation. Alkaline phosphatase (ALP) activity of MG-63 cells was found to be the highest on PLLA/Gel/HA at day 7 compared to all other scaffolds. Complement activation study revealed minimum terminal complement complex (TCC) concentration for PLLA/Gel and PLLA/Gel/HA (617.33 and 654.13 ng/mL respectively). These results demonstrate the proficiency of PLLA/Gel/HA scaffold in better osteostimulation with lesser immune response, which attributed to synergistic role of gelatin and HA. Thus, by mimicking the natural microenvironment PLLA/Gel/HA scaffolds can become the choice of material in bone tissue engineering.

  4. Is chlorhexidine-methacrylate as effective as chlorhexidine digluconate in preserving resin dentin interfaces?

    PubMed

    Abu Nawareg, Manar; Elkassas, Dina; Zidan, Ahmed; Abuelenain, Dalia; Abu Haimed, Tariq; Hassan, Ali H; Chiba, Ayaka; Bock, Thorsten; Agee, Kelli; Pashley, David H

    2016-02-01

    The aim of the current study was to evaluate the effect of 2% CHX and 2% CHX-methacrylate compared to the resin-dentin bonds created by a two-step etch-and-rinse adhesive system after 24h, 6min and 12min. Microtensile bond strengths and interfacial nanoleakage within resin-dentin interfaces created by Adper Single Bond 2, with or without CHX or CHX-methacrylate pre-treatment for 30s on acid-etched dentin surfaces, were evaluated after 24h, 6min and 12min of storage in distilled water at 37°C. Twelve months of storage resulted in a significant decrease in microtensile bond strength in the control group, and significant increases in silver nanoleakage. In contrast, Single Bond 2+CHX, and to a greater extent CHX-methacrylate, significantly reduced the rate of deterioration of resin-dentin interfaces over the 12min water storage period, in terms of bond strength. Similar to Single Bond 2+CHX, Single Bond+CHX-methacrylates reduced the degradation of resin-bonded interfaces over a 12 month storage period. Thus it can be concluded that Single Bond 2+CHX-methacrylate may be important to improve durability of bonded interfaces and therefore, prolong the life span of adhesive restorations. Although CHX primers have been shown to enhance the durability of etch-and-rinse adhesives, that protection is lost after 2h. The use of CHX-methacrylate should last much longer since it may copolymerize with adhesive monomers, unlike CHX. Copyright © 2015 Elsevier Ltd. All rights reserved.

  5. Gelatinous bone marrow in an HIV-positive patient

    PubMed Central

    Stephens, Johnny R.; Baker, Damon L.

    2007-01-01

    Gelatinous bone marrow transformation has been identified in patients with anorexia, malignancy, malabsorption, and HIV/AIDS. This represents a deposition of gelatinous material within the bone marrow, along with atrophy. We report the case of an HIV-seropositive man who presented with low back pain related to his gelatinous bone marrow changes. PMID:17637880

  6. Gelatinous bone marrow in an HIV-positive patient.

    PubMed

    Stroup, Jeffrey S; Stephens, Johnny R; Baker, Damon L

    2007-07-01

    Gelatinous bone marrow transformation has been identified in patients with anorexia, malignancy, malabsorption, and HIV/AIDS. This represents a deposition of gelatinous material within the bone marrow, along with atrophy. We report the case of an HIV-seropositive man who presented with low back pain related to his gelatinous bone marrow changes.

  7. Glycol methacrylate embedding in histotechnology: the hematoxylin-eosin stain as a method for assessing the stability of glycol methacrylate sections.

    PubMed

    Gerrits, P O; van Leeuwen, M B

    1987-05-01

    Glycol methacrylate (GMA) samples containing inhibitor in the range of 200-300 ppm were included in a standard embedding mixture. The pH of the GMA samples was measured as a 10% solution of the sample in distilled water. The acidity of GMA due to methacrylic acid causes background staining of sections after basic dyes. The concentration of GMA and the amount of impurities such as methacrylic acid (MA) and ethylene glycol dimethacrylate (EDMA) were measured by gas chromatography. Distinct variations in purity were found among five samples of GMA. Sections derived from GMA samples containing more than 2% EDMA showed few, if any, minifolds after staining with hematoxylin and eosin and were more stable in alcoholic and basic solutions; sections from purer GMA showed minifolds and were less stable. Addition of crosslinkers, EDMA or triethylene glycol dimethacrylate (TEDMA) prevented these artifacts. Crosslinkers clearly influence dimensional changes in sections. Addition of crosslinkers to GMA samples containing minimal amounts of MA improved the results. The possibility of obtaining a high quality GMA embedding medium is discussed.

  8. Electro-Responsive Behaviour Multi-Wall Nanotubes/Gelatin Composites and Cross-Linked Gelatin Electrospun Mats

    DTIC Science & Technology

    2008-02-11

    1 Final Report on Electro-responsive behaviour multi-wall nanotubes /gelatin composites and cross-linked gelatin electrospun mats...12-10-2007 4. TITLE AND SUBTITLE Electro-responsive behaviour multi-wall nanotubes /gelatin composites and cross-linked gelatin electrospun mats...such as polymer gels 2-3, conducting polymers 4-5, carbon nanotube composites 6-8, and dielectric elastomers 9 are some of the most promising materials

  9. A genipin-gelatin gel dosimeter for radiation processing

    NASA Astrophysics Data System (ADS)

    Davies, J. B.; Bosi, S. G.; Baldock, C.

    2012-08-01

    Genipin, a fruit extract from Gardenia jasminoides Ellis, forms cross-links in solutions of gelatin, to form a blue hydrogel that bleaches quantitatively upon irradiation and the colour change can be measured with a spectrophotometer. With the addition of sulphuric acid this dosimeter is sufficiently sensitive for quality assurance of radiotherapy level dosimetry. Without sulphuric acid the gel has a reduced sensitivity and responds linearly with dose between 100 and 1000 Gy, making it potentially useful as a dosimeter for radiation processing applications such as the phytosanitary irradiation treatment of food. We investigated the dose response characteristics of this new formulation and found that the darker gels are more sensitive to dose and have a reduced uncertainty.

  10. Synthesis of Methyl Methacrylate From Coal-Derived Syngas

    SciTech Connect

    Ben W.-L. Jang; Gerald N. Choi; James J. Spivey; Jospeh R. Zoeller; Richard D. Colberg; Samuel S. Tam

    1998-07-27

    Research Triangle Institute (RTI), Eastman Chemical Company, and Bechtel collectively are developing a novel three-step process for the synthesis of methyl methacrylate (MMA) from coal-derived syngas that consists of the steps of synthesis of a propionate, its condensation with formaldehyde to form methacrylic acid (MAA), and esterification of MAA with methanol to produce MMA. RTI has completed the research on the three-step methanol-based route to MMA. Under an extension to the original contract, RTI is currently evaluating a new DME-based process for MMA. The key research need for DME route is to develop catalysts for DME partial oxidation reactions and DME condensation reactions. Over the last quarter(April-June, 1998), RTI has modified the reactor system including a new preheater and new temperature settings for the preheater. Continuous condensation of formaldehyde with propionic acid were carried out over 10% Nb O /SiO at 300°C without 2 5 2 interruption. Five activity and four regeneration cycles have been completed without plugging or material balance problems. The results show that 10% Nb O /SiO deactivates slowly with time 2 5 2 but can be regenerated, at least four times, to 100% of its original activity with 2% O in nitrogen 2 at 400°C. The cycles continue with consistent 90-95% of carbon balance. The reaction is scheduled to complete with 6 activity cycles and 5 regenerations. Used catalysts will be analyzed with TGA and XPS to determine bulk and surface coke content and coke properties. RTI will start the investigation of effects of propionic acid/formaldehyde ratio on reaction activity and product selectivity over 20% Nb O /SiO catalysts.

  11. Microfluidics-Assisted Fabrication of Gelatin-Silica Core–Shell Microgels for Injectable Tissue Constructs

    PubMed Central

    2013-01-01

    Microfabrication technology provides a highly versatile platform for engineering hydrogels used in biomedical applications with high-resolution control and injectability. Herein, we present a strategy of microfluidics-assisted fabrication photo-cross-linkable gelatin microgels, coupled with providing protective silica hydrogel layer on the microgel surface to ultimately generate gelatin-silica core–shell microgels for applications as in vitro cell culture platform and injectable tissue constructs. A microfluidic device having flow-focusing channel geometry was utilized to generate droplets containing methacrylated gelatin (GelMA), followed by a photo-cross-linking step to synthesize GelMA microgels. The size of the microgels could easily be controlled by varying the ratio of flow rates of aqueous and oil phases. Then, the GelMA microgels were used as in vitro cell culture platform to grow cardiac side population cells on the microgel surface. The cells readily adhered on the microgel surface and proliferated over time while maintaining high viability (∼90%). The cells on the microgels were also able to migrate to their surrounding area. In addition, the microgels eventually degraded over time. These results demonstrate that cell-seeded GelMA microgels have a great potential as injectable tissue constructs. Furthermore, we demonstrated that coating the cells on GelMA microgels with biocompatible and biodegradable silica hydrogels via sol–gel method provided significant protection against oxidative stress which is often encountered during and after injection into host tissues, and detrimental to the cells. Overall, the microfluidic approach to generate cell-adhesive microgel core, coupled with silica hydrogels as a protective shell, will be highly useful as a cell culture platform to generate a wide range of injectable tissue constructs. PMID:24344625

  12. Gelatin-based nanoparticles as DNA delivery systems: Synthesis, physicochemical and biocompatible characterization.

    PubMed

    Morán, M C; Rosell, N; Ruano, G; Busquets, M A; Vinardell, M P

    2015-10-01

    The rapidly rising demand for therapeutic grade DNA molecules requires associated improvements in encapsulation and delivery technologies. One of the challenges for the efficient intracellular delivery of therapeutic biomolecules after their cell internalization by endocytosis is to manipulate the non-productive trafficking from endosomes to lysosomes, where degradation may occur. The combination of the endosomal acidity with the endosomolytic capability of the nanocarrier can increase the intracellular delivery of many drugs, genes and proteins, which, therefore, might enhance their therapeutic efficacy. Among the suitable compounds, the gelification properties of gelatin as well as the strong dependence of gelatin ionization with pH makes this compound an interesting candidate to be used to the effective intracellular delivery of active biomacromolecules. In the present work, gelatin (either high or low gel strength) and protamine sulfate has been selected to form particles by interaction of oppositely charged compounds. Particles in the absence of DNA (binary system) and in the presence of DNA (ternary system) have been prepared. The physicochemical characterization (particle size, polydispersity index and degree of DNA entrapment) have been evaluated. Cytotoxicity experiments have shown that the isolated systems and the resulting gelatin-based nanoparticles are essentially non-toxic. The pH-dependent hemolysis assay and the response of the nanoparticles co-incubated in buffers at defined pHs that mimic extracellular, early endosomal and late endo-lysosomal environments demonstrated that the nanoparticles tend to destabilize and DNA can be successfully released. It was found that, in addition to the imposed compositions, the gel strength of gelatin is a controlling parameter of the final properties of these nanoparticles. The results indicate that these gelatin-based nanoparticles have excellent properties as highly potent and non-toxic intracellular delivery

  13. Electrospun gelatin fiber mats containing a herbal—Centella asiatica—extract and release characteristic of asiaticoside

    NASA Astrophysics Data System (ADS)

    Sikareepaisan, Panprung; Suksamrarn, Apichart; Supaphol, Pitt

    2008-01-01

    Ultra-fine gelatin (type A, porcine skin, ~180 Bloom) fiber mats containing a methanolic crude extract of Centella asiatica (L.) Urban, a medicinal plant widely known for its traditional medical applications including its wound healing ability, were fabricated, for the first time, from the neat gelatin solution (22% w/v in 70 vol% acetic acid) containing the crude extract (mCA) in various amounts (i.e. 5-30 wt% based on the weight of gelatin powder) by electrospinning. Incorporation of mCA in the neat gelatin solution did not affect both the morphology and the size of the mCA-loaded gelatin fibers, as both of the neat and the mCA-loaded gelatin fibers were smooth and the average diameters of these fibers ranged between 226 and 232 nm. The cross-linked mCA-loaded e-spun gelatin fiber mat from the neat gelatin solution containing 30 wt% of mCA was further investigated for the release characteristic of asiaticoside, identified as the most active compound associated with the healing of wounds, in two different types of releasing medium, i.e. acetate buffer and the buffer containing 10 vol% of methanol, based on the thin-layer chromatography (TLC)-densitometry technique. Based on the unit weight of the actual amount of asiaticoside present in the specimens, the total amount of asiaticoside released from the fiber mat specimens was lower than that from the film counterparts while, based on the unit weight of the specimens, an opposite trend was observed.

  14. Surface modification of nanofibrous polycaprolactone/gelatin composite scaffold by collagen type I grafting for skin tissue engineering.

    PubMed

    Gautam, Sneh; Chou, Chia-Fu; Dinda, Amit K; Potdar, Pravin D; Mishra, Narayan C

    2014-01-01

    In the present study, a tri-polymer polycaprolactone (PCL)/gelatin/collagen type I composite nanofibrous scaffold has been fabricated by electrospinning for skin tissue engineering and wound healing applications. Firstly, PCL/gelatin nanofibrous scaffold was fabricated by electrospinning using a low cost solvent mixture [chloroform/methanol for PCL and acetic acid (80% v/v) for gelatin], and then the nanofibrous PCL/gelatin scaffold was modified by collagen type I (0.2-1.5wt.%) grafting. Morphology of the collagen type I-modified PCL/gelatin composite scaffold that was analyzed by field emission scanning electron microscopy (FE-SEM), showed that the fiber diameter was increased and pore size was decreased by increasing the concentration of collagen type I. Fourier transform infrared (FT-IR) spectroscopy and thermogravimetric (TG) analysis indicated the surface modification of PCL/gelatin scaffold by collagen type I immobilization on the surface of the scaffold. MTT assay demonstrated the viability and high proliferation rate of L929 mouse fibroblast cells on the collagen type I-modified composite scaffold. FE-SEM analysis of cell-scaffold construct illustrated the cell adhesion of L929 mouse fibroblasts on the surface of scaffold. Characteristic cell morphology of L929 was also observed on the nanofiber mesh of the collagen type I-modified scaffold. Above results suggest that the collagen type I-modified PCL/gelatin scaffold was successful in maintaining characteristic shape of fibroblasts, besides good cell proliferation. Therefore, the fibroblast seeded PCL/gelatin/collagen type I composite nanofibrous scaffold might be a potential candidate for wound healing and skin tissue engineering applications. © 2013.

  15. Novel catalysts for the environmentally friendly synthesis of methyl methacrylate

    SciTech Connect

    Spivey, J.J.; Gogate, M.R.; Zoeller, J.R.; Colberg, R.D.

    1997-11-01

    The development of a process for the synthesis of methyl methacrylate (MMA) from coal-derived syngas can alleviate the environmental hazards associated with the current commercial MMA technology, the acetone cyanohydrin (ACH) process. A three-step syngas-based process consisted of synthesis of a propionic acid, its condensation with formaldehyde, and esterification of resulting methacrylic acid (MAA) to form MMA. The first two steps, propionic acid synthesis and condensation, are discussed here. The low-temperature, low-pressure process for single-step hydrocarbonylation of ethylene to propionic acid is carried out using a homogeneous iodine-promoted Mo(CO){sub 6} catalyst at pressures (30--70 atm) and temperatures (150--200 C) lower than those reported for other catalysts. Mechanistic investigations suggest that catalysis is initiated by a rate-limiting CO dissociation from Mo(CO){sub 6}. This dissociation appears to be followed by an inner electron-transfer process of an I atom from EtI to the coordinately unsaturated Mo(CO){sub 5}. This homogeneous catalyst for propionate synthesis represents the first case of an efficient carbonylation process based on Cr group metals. The condensation of formaldehyde with propionic acid is carried out by acid-base bifunctional catalysts. As a result of screening over 80 catalytic materials, group V metals supported on an amorphous silica are found to be most effective. A 20% Nb/SiO{sub 2} catalyst appears to be the most active and stable catalyst thus far. Preliminary relations among the reaction yield and catalyst properties indicate that a high surface area and a low overall surface acidity (<50 = mol of NH{sub 3}/g), with a high proportion of the acidity being weak (<350 C desorption of NH{sub 3}), are desirable. Long-term deactivation of V-Si-P, Nb-Si, and Ta-Si catalysts suggests that carbon deposition is the primary cause for activity decay, and the catalyst activity is partially restorable by oxidative regeneration.

  16. Dendrimer/methyl methacrylate co-polymers: residual methyl methacrylate and degree of conversion.

    PubMed

    Viljanen, Eeva K; Skrifvars, Mikael; Vallittu, Pekka K

    2005-01-01

    Dendrimer/methyl methacrylate co-polymers were studied for use in dental composites. The aim was to determine the effects of methyl methacrylate concentration in the resin mixture and polymerization method on the degree of conversion and residual monomer content of the copolymers. Two dendrimers were studied, D12 with 12 reactive methacrylate groups and D24 with 24 reactive groups. The concentration of methyl methacrylate varied from 20 wt% to 50 wt% of monomers. Camphorquinone (CQ) was used as the light-activation initiator and 2-(N,N-dimethylamino)ethyl methacrylate (DMAEMA) as the activator, both in the quantity of 3.0 wt%. Three polymerization methods were used: photo-polymerization, photo-polymerized immediately followed by post-polymerization at 120 degrees C for 15 min, and photo-polymerization followed by postpolymerization after 7 days. The degree of conversion was determined using FT-IR. Residual monomers were extracted with tetrahydrofuran and methanol and analyzed with HPLC. The highest degrees of conversion were 65 and 62%, and the lowest residual monomer contents 1.0 and 1.5% for D12 and D24, respectively. These were measured after heat-induced post-polymerization. For D12, increasing the proportion of methyl methacrylate decreased the degree of conversion and increased the residual monomer content after photo-polymerization. Post-polymerization enhanced the polymerization of the dendrimer co-polymers in respect of degree of conversion and residual monomer content. The present study suggested that the tested dendrimer/methyl methacrylate copolymers require heat-induced polymerization to reach the generally accepted levels of degree of conversion and residual monomers.

  17. State of water in gelatin Gels

    SciTech Connect

    Naryshkina, E.P.; Izmailova, V.N.; Polinnyi, A.I.

    1986-03-01

    It has been shown on the basis of the variation of the linewidth of water with time in high-resolution NMR spectra of gelatin gels in D/sub 2/O that there is a decrease in the mobility of the water molecules during the formation of the collagen-like helix in the initial stages of gelation. As the concentration of the protein is increased, the linewidth of the water signal ..delta.. increases, and the spin-spin (T/sub 2/) and spin-lattice (T/sub 1/) relaxation times and the self-diffusion coefficient of the water molecules D /SUB S/ in the fully formed gels of gelatin in H/sub 2/O decreases as a result of the immobilization of water by the gelatin macromolecules and the presence of a three-dimensional gel network. The aforementioned parameters vary as a function of the gelatin concentration in parallel with the value of the Flory-Huggins parameter /CHI/.

  18. Rifle bullet penetration into ballistic gelatin.

    PubMed

    Wen, Yaoke; Xu, Cheng; Jin, Yongxi; Batra, R C

    2017-03-01

    The penetration of a rifle bullet into a block of ballistic gelatin is experimentally and computationally studied for enhancing our understanding of the damage caused to human soft tissues. The gelatin is modeled as an isotropic and homogeneous elastic-plastic linearly strain-hardening material that obeys a polynomial equation of state. Effects of numerical uncertainties on penetration characteristics are found by repeating simulations with minute variations in the impact speed and the angle of attack. The temporary cavity formed in the gelatin and seen in pictures taken by two high speed cameras is found to compare well with the computed one. The computed time histories of the hydrostatic pressure at points situated 60 mm above the line of impact are found to have "two peaks", one due to the bullet impact and the other due to the bullet tumbling. Contours of the von Mises stress and of the effective plastic strain in the gelatin block imply that a very small region adjacent to the cavity surface is plastically deformed. The angle of attack is found to noticeably affect the penetration depth at the instant of the bullet tumbling through 90°. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. Equation of State of Ballistic Gelatin

    DTIC Science & Technology

    2008-06-23

    We determined the equation of state for ballistic gelatin using the Brillouin scattering spectroscopy with a diamond anvil cell by measuring the...0 to 100 deg C between ambient and 12 GPa. We analyzed the Brillouin data using a high temperature Vinet equation of state and obtained the bulk

  20. Equation of State of Ballistic Gelatin (II)

    DTIC Science & Technology

    2011-01-03

    We determined the equation of state of ballistic gelatin (20%) using Brillouin scattering spectroscopy with diamond anvil cells by measuring the...purposes, we also measured the pressure dependence of sound velocity of lamb tissues up to 10 GPa. We analyzed the Brillouin data using the Vinet equation of state and

  1. Grating Formation in Diazo Salt (Sensitized) Gelatin,

    DTIC Science & Technology

    1979-10-03

    AD-AO8O 745 ARMY ENBINEER TOPOGRAPHIC LABS FORT BrLVOR VA " 7 *RATING FORMATION IN DIAZO SALT (SENSITIZED) GELATIN,(U) OCT 79 J V GLAOOEM...arrangements. The diffraction efficiency was measured as a quotient of the power diffrated into the first order beam and the power in the incident

  2. Multilayered polycaprolactone/gelatin fiber-hydrogel composite for tendon tissue engineering.

    PubMed

    Yang, Guang; Lin, Hang; Rothrauff, Benjamin B; Yu, Shuting; Tuan, Rocky S

    2016-04-15

    Regeneration of injured tendon and ligament (T&L) remains a clinical challenge due to their poor intrinsic healing capacity. Tissue engineering provides a promising alternative treatment approach to facilitate T&L healing and regeneration. Successful tendon tissue engineering requires the use of three-dimensional (3D) biomimetic scaffolds that possess the physical and biochemical features of native tendon tissue. We report here the development and characterization of a novel composite scaffold fabricated by co-electrospinning of poly-ε-caprolactone (PCL) and methacrylated gelatin (mGLT). We found that photocrosslinking retained mGLT, resulted in a uniform distribution of mGLT throughout the depth of scaffold and also preserved scaffold mechanical strength. Moreover, photocrosslinking was able to integrate stacked scaffold sheets to form multilayered constructs that mimic the structure of native tendon tissues. Importantly, cells impregnated into the constructs remained responsive to topographical cues and exogenous tenogenic factors, such as TGF-β3. The excellent biocompatibility and highly integrated structure of the scaffold developed in this study will allow the creation of a more advanced tendon graft that possesses the architecture and cell phenotype of native tendon tissues. The clinical challenges in tendon repair have spurred the development of tendon tissue engineering approaches to create functional tissue replacements. In this study, we have developed a novel composite scaffold as a tendon graft consisting of aligned poly-ε-caprolactone (PCL) microfibers and methacrylated gelatin (mGLT). Cell seeding and photocrosslinking between scaffold layers can be performed simultaneously to create cell impregnated multilayered constructs. This cell-scaffold construct combines the advantages of PCL nanofibrous scaffolds and photocrosslinked gelatin hydrogels to mimic the structure, mechanical anisotropy, and cell phenotype of native tendon tissue. The scaffold

  3. Caseinate-gelatin and caseinate-hydrolyzed gelatin composites formed via transglutaminase: chemical and functional properties.

    PubMed

    Luo, Zhen-Ling; Zhao, Xin-Huai

    2015-11-01

    Treatment of food proteins by enzymatic crosslinking and other reactions can confer modified properties on the treated proteins. Bovine gelatin and hydrolyzed bovine gelatin were used to generate two caseinate-based composites via transglutaminase, and potential useful properties to food processing were investigated for both composites. Caseinate-gelatin and caseinate-hydrolyzed gelatin composites contained 33.4 and 10.3 g kg(-1) protein of 4-hydroxyproline, respectively. Caseinate conjugation with gelatin and hydrolyzed gelatin resulted in two composites with stronger absorption at five wavenumbers during Fourier transform-infrared analysis, demonstrating that they were rich in hydroxyl and carboxyl groups. Both composites exhibited higher viscosity values in aqueous dispersions, lower thermal stability (i.e. higher mass loss) during thermogravimetric analysis and worse emulsifying properties than original caseinate, owing to conjugation and crosslinking via transglutaminase. However, confocal laser scanning microscopy (CLSM) analysis revealed that both composites actually had better emulsion stability after 2 weeks of storage. The composites generated were different in chemical characteristics and better in viscosity and emulsion stability than original caseinate. They might have potential as protein thickeners and emulsifiers. CLSM is a better technique to assess emulsion stability of food proteins than the classic turbidity method. © 2014 Society of Chemical Industry.

  4. Porous conductive polyblends of polyaniline in poly(methyl methacrylate)

    NASA Astrophysics Data System (ADS)

    Price, Aaron D.; Naguib, Hani E.

    2008-03-01

    The conductive polymer polyaniline is typically blended with conventional industrial thermoplastics in order to obtain an electrically conductive polymer blend with adequate mechanical properties. Processing these polyblends into foams yields a porous conductive material that exhibits immense application potential such as dynamic separation media and low-density electrostatic discharge protection. In the current study, the morphology of a thermally-processable blend consisting of an electrically conductive polyaniline-dodecylbenzene sulfonic acid complex and poly(methyl methacrylate) is explored using a two-phase batch foaming setup. The effect of blend composition and processing parameters on the resulting cellular morphology is investigated. Finally, the impact of the underlying microstructure on the frequency dependent electrical conductivity is elucidated.

  5. A pre-formed methyl methacrylate cranioplasty.

    PubMed

    Cooper, P R; Schechter, B; Jacobs, G B; Rubin, R C; Wille, R L

    1977-09-01

    The use of a pre-formed methyl methacrylate cranioplasty prosthesis reinforced with stainless steel wire is described. The prosthesis is non-reactive, virtually unbreakable, and undentable. Pre-forming of the prosthesis in the dental laboratory using a mold of the patient's bony defect as a model saves considerable operating time, and when employed for a large cranial defect the three dimensional cosmetic effect is superior to intra-operatively fashioned prostheses.

  6. Solubilization of bovine gelatin using power ultrasound: gelation without heating.

    PubMed

    Farahnaky, Asgar; Zendeboodi, Fatemeh; Azizi, Rezvan; Mesbahi, Gholamreza; Majzoobi, Mahsa

    2017-04-01

    The aim of this study was to investigate the efficacy of power ultrasound without using any heating stage in solubilizeing gelatin dispersions, and to characterize the mechanical and microstructural properties of the resulting gels using texture analysis and scanning electron microscopy, respectively. Usually to prepare a gel from gelatin, a primary heating stage of at about 40C or above is required to solubilize gelatin macromolecules. In this study solubilizing gelatin dispersions using power ultrasound without any heating was successfully performed. For solubilising gelatin, an ultrasound equipment with a frequency of 20 kHz, amplitude of 100% and power range of 50-150 W was used. Aqueous gelatin dispersions (4% w/v) were subjected to ultrasound for different times (40-240 s) at a constant temperature of 13C. Applying ultrasound to gelatin dispersions caused increases in water absorption and water solubility of the hydrocolloid. The textural parameters of the resulting gelatin gels, increased with increasing time and power of ultrasound. Moreover, a generalized Maxwell model with three elements was used for calculating relaxation times of the gels. The microstructural observations by SEM showed that the structural cohesiveness of the gels increased by increasing ultrasonication time. Ultrasound-assisted solubilization of gelatin can have emerging implications for industrial uses in pharmaceuticals, food and non-food systems. Usually to prepare a gel from gelatin, a primary heating stage of at about 40C or above is required to solubilize gelatin macromolecules. Therefore, the use of gelatin as a hydrocolloid in food processings or pharmaceutical formulations which lack a heating step has been a technological and practical challenge. In this study solubilizing gelatin dispersions using power ultrasound without any heating was successfully performed. Ultrasound-assisted solubilisation of gelatin can have emerging implications for industrial uses in pharmaceuticals

  7. Dimensional accuracy of thermoformed polymethyl methacrylate.

    PubMed

    Jagger, R G

    1996-12-01

    Thermoforming of polymethyl methacrylate sheet is used to produce a number of different types of dental appliances. The purpose of this study was to determine the dimensional accuracy of thermoformed polymethyl methacrylate specimens. Five blanks of the acrylic resin were thermoformed on stone casts prepared from a silicone mold of a brass master die. The distances between index marks were measured both on the cast and on the thermoformed blanks with an optical comparator. Measurements on the blanks were made again 24 hours after processing and then 1 week, 1 month, and 3 months after immersion in water. Linear shrinkage of less than 1% (range 0.37% to 0.52%) was observed 24 hours after removal of the blanks from the cast. Immersion of the thermoformed specimens in water resulted in an increase in measured dimensions, but after 3 months' immersion these increases were still less than those of the cast (range 0.07% to 0.18%). It was concluded that it is possible to thermoform Perspex polymethyl methacrylate accurately.

  8. Reactivity of methacrylates in insertion polymerization.

    PubMed

    Rünzi, Thomas; Guironnet, Damien; Göttker-Schnetmann, Inigo; Mecking, Stefan

    2010-11-24

    Polymerization of ethylene by complexes [{(P^O)PdMe(L)}] (P^O = κ(2)-(P,O)-2-(2-MeOC(6)H(4))(2)PC(6)H(4)SO(3))) affords homopolyethylene free of any methyl methacrylate (MMA)-derived units, even in the presence of substantial concentrations of MMA. In stoichiometric studies, reactive {(P^O)Pd(Me)L} fragments generated by halide abstraction from [({(P^O)Pd(Me)Cl}μ-Na)(2)] insert MMA in a 1,2- as well as 2,1-mode. The 1,2-insertion product forms a stable five-membered chelate by coordination of the carbonyl group. Thermodynamic parameters for MMA insertion are ΔH(++) = 69.0(3.1) kJ mol(-1) and ΔS(++) = -103(10) J mol(-1) K(-1) (total average for 1,2- and 2,1-insertion), in comparison to ΔH(++) = 48.5(3.0) kJ mol(-1) and ΔS(++) = -138(7) J mol(-1) K(-1) for methyl acrylate (MA) insertion. These data agree with an observed at least 10(2)-fold preference for MA incorporation vs MMA incorporation (not detected) under polymerization conditions. Copolymerization of ethylene with a bifunctional acrylate-methacrylate monomer yields linear polyethylenes with intact methacrylate substituents. Post-polymerization modification of the latter was exemplified by free-radical thiol addition and by cross-metathesis.

  9. A novel gelatin-based micro-cavitary hydrogel for potential application in delivery of anchorage dependent cells: A study with vasculogenesis model.

    PubMed

    Leong, Wenyan; Fan, Changjiang; Wang, Dong-An

    2016-10-01

    Hydrogels have been widely regarded as promising tissue engineering scaffolds and cell delivery vehicles, however, their inherent submicron- or nano-scale polymer networks severely inhibit the settlement of anchorage dependent cells (ADCs). Here, using endothelial progenitor outgrowth cells (EPOCs) as the typical ADCs, a gelatin-based micro-cavitary gel (namely Gel-MCG) is developed with gelatin-methacrylate and gelatin microspheres as precursor and porogens, respectively, to promote cellular focal adhesion and functions. The introduction of micro-cavitary structures within the Gel-MCG improves its physical properties as well as creates numerous gel-microcavity interfaces within gel-based matrices. Compared with conventional gelatin gel (Gel-G) scaffold, the Gel-MCG provides more suitable microenvironments for EPOCs' attachment, spreading, and proliferation, and then which leads to enhanced endothelial differentiation and vascularization as demonstrated by higher expressions of endothelial markers. The Gel-MCG system shows great potential as vehicle for the delivery of ADCs in tissue engineering. Copyright © 2016 Elsevier B.V. All rights reserved.

  10. Vascular responsiveness to dimethylaminoethyl methacrylate and its degradation products.

    PubMed

    Abebe, Worku; Maddux, William F; Schuster, George S; Lewis, Jill B

    2003-07-01

    The increasing use of acrylate-based resins in dentistry has raised questions about the biocompatibility of these substances with oral tissues. The focus of the present investigation was to assess the responsiveness of blood vessels to the resin polymerization accelerating agent dimethylaminoethyl methacrylate (DMAEMA) and its degradation products dimethylethanolamine (DME) and methacrylic acid (MAA), using the rat aortic ring preparation as a tissue model. DMAEMA induced concentration-dependent relaxation of norepinephrine (NE)-contracted aortic rings with and without endothelium. N-nitro-L-arginine methyl ester (L-NAME) selectively inhibited the endothelium-dependent relaxation induced by DMAEMA, suggesting the release of nitric oxide from the endothelium by DMAEMA. Both indomethacin and glybenclamide attenuated the vasorelaxation elicited by DMAEMA in the presence as well as in the absence of endothelium, providing evidence for the role of vasorelaxant prostanoid(s) and K(ATP) channel activation in the responses observed. On the other hand, while MAA was without any apparent effect on the rat aorta, DMAEMA at high and DME at relatively low concentrations caused contraction of the tissues with and without endothelium in the absence of NE. The DME-induced contraction was inhibited by indomethacin, suggesting the involvement of contractile arachidonic acid metabolite(s) in the action of DME. This observation was supported by the findings of increased thromboxane A(2) (TXA(2)) production in aortic rings incubated with DME. Taken together, the data suggest that both DMAEMA and its degradation product, DME, are vasoactive, inducing vasorelaxation and contraction by various mechanisms that may involve the release of nitric oxide from the endothelium, the activation of smooth