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Controlled drug delivery is a key strategy aimed at reducing both the frequency of therapeutic dosages and potential systemic side effects, particularly in the case of high drug concentrations. The nanocomposite hydrogel systems presented in this study were synthesized by combining carboxymethyl cellulose, polyvinyl alcohol, and (3-aminopropyl)triethoxysilane-functionalized halloysite nanotubes (fHNTs). This hydrogel system is a potential candidate for the controlled release of cefadroxil monohydrate. These hydrogels are analyzed by Fourier transform infrared spectroscopy, scanning electron microscopy, thermogravimetric analysis, and rheological measurements. Additionally, swelling properties, porosity, hydrophilicity, drug release, and in vitro and in vivo analyses were also evaluated. The observed trends in swelling and drug release demonstrated that the outcomes are dependent on the presence of fHNTs in the hydrogel matrix. Notably, fHNTs-loaded hydrogels displayed sustained drug release patterns. This innovative approach eliminates the need for traditional encapsulation and presents promising and translatable strategies for achieving more effective drug release.
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Declining freshwater resources along with their pollution are threatening the life existence on earth. To meet the freshwater demand, one of the most appropriate and possible ways which has been adopted all over the world is to reuse wastewater by removing its impurities. Among many water pollutants, natural organic matter (NOM) is found to be responsible as major precursor for the formation of other pollutants. Removal of NOM from wastewater is being done by using membrane filtration systems incorporated with certain nanofillers to increase membranes efficiency and permeability. In this study, novel nanocomposite reverse osmosis (RO) membranes were prepared using cellulose acetate and chitosan in N,N-Dimethyl formamide. Graphene oxide (GO) nanosheets and zinc oxide (ZnO) in different concentration were loaded to modify the membranes for tuning their RO performance. The confirmation of the functional groups is demonstrated by Fourier transform infrared spectroscopy which revealed the specific peaks indicating the formation of the nano-composite membranes. The surface morphology was studied by scanning electronic microscopy which shows a gradual transformation of the membrane surface from voids-free to macro-voids filled surface up to threshold concentration of GO and ZnO. The thermal properties of GO based membranes were analyzed using thermogravimetric analysis and differential scanning calorimetry. The uniform interaction of the GO and ZnO with polymers induced the remarkable thermal properties of the synthesized membranes. Permeate flux and contact angle measurements were considered to estimate their water content (96%) capacity and NOM rejection (96%) using 0.1 ppm humic acid solution. The permeate flux, NOM rejection and the water content changed directly with GO and inversely with ZnO wt% in the membranes up to GO5 (GO:0.14: ZnO:0.03) whereas the contact angle exhibited the inverse relationship with GO and ZnO concentration in casting solution of the synthesized membranes. Hence it can be concluded that prepared RO membranes are suitable for NOM rejection and recommended for water treatment.
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pH responsive hydrogels have gained much attraction in biomedical fields. We have formulated ternary hydrogel films as a new carrier of drug. Polyelectrolyte complex of chitosan/guar gum/polyvinyl pyrrolidone cross-linked via sodium tripolyphosphate was developed by solution casting method. Fourier transform infrared spectroscopy, scanning electron microscopy and thermogravimetric analysis were conducted to examine the interactions between the polymeric chains, surface morphology and thermal stability, respectively. The swelling tests resulted that the swelling was reduced with the increase in the concentration of crosslinker due to the more entangled arrangement and less availability of pores in hydrogels. Ciprofloxacin hydrochloride was used as a model drug and its release in simulated gastric fluid, simulated intestinal fluid and phosphate buffer saline solution was studied. pH responsive behaviour of the hydrogels have subjected these hydrogels for drug release applications.
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Quitosana/química , Portadores de Fármacos/química , Galactanos/química , Concentração de Íons de Hidrogênio , Mananas/química , Metilgalactosídeos/química , Gomas Vegetais/química , Povidona/química , Materiais Biocompatíveis/química , Fenômenos Químicos , Sistemas de Liberação de Medicamentos , Liberação Controlada de Fármacos , Estrutura Molecular , Análise Espectral , TermogravimetriaRESUMO
In this study, biodegradable polymeric films (BPFs) based on chitosan and acrylic acid cross-linked with 3-aminopropyl triethoxysilane (APTES) were developed for water retention and soil-conditioning applications in areas sufferings from water scarcity. A series of BPFs were prepared by varying the amount of silica nanoparticles (SiNPs) (0.67% to 2.6%) and a correlation of the optimum amount of SiNPs with thermal stability, morphology, swellability (at various pH), degradability, and anti-microbial activity were deduced. The obtained results showed that the NP 8 (containing 2.51% of SiNPs) exhibited the maximum absorption capacity (1815%) in distilled water, whereas NP6 (including 1.88% of SiNPs) expressed the maximum thermal stability (T50% at 375.61 °C). The microscopic images further strengthen this observation because the maximum number of micro-porous cavities was shown on the surface of NP8. The time-dependent swelling response in distilled water accomplished that hydrophilicity (percentage swelling) of films was enhanced with an increase in the concentration of SiNPs. All BPFs samples exhibited inhibitory response against both gram-positive (for Staphylococcus aureus was 2.9 cm for NP6) and gram-negative (for Escherichia coli was 0.9 cm for NP8) bacteria. The biodegradation test inferred that the degradation of BPFs in soil did not affect the soil fertility as nano-silica is proven as growth-promoting miniatures. It can be concluded that these BPFs may be efficiently employed in the agriculture sector for water retention and as a soil conditioner.
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Acrilatos/química , Plásticos Biodegradáveis/síntese química , Quitosana/análogos & derivados , Solo/química , Plásticos Biodegradáveis/farmacologia , Nanopartículas/química , Dióxido de Silício/química , Staphylococcus aureus/efeitos dos fármacos , MolhabilidadeRESUMO
Chronic non-healing wounds tender a great challenge to patients, physicians, and wound care professionals. In view of the increasing prevalence of chronic wounds due to ischemia, diabetic foot, venous, and pressure ulcers, their appropriate management requires significant attention. Along with the basic techniques of medical and surgical treatments; an ideal dressing is essential for a speedy recovery and rapid healing of such wounds. Mechanistic understanding of chronic wound pathology will not only help towards future directions for an ideal dressing model but also to resonant advance research related to specific dressings for various wound types. This review provides key insights into causes, pathophysiology, and critical issues pertaining to chronic wounds and their management. It also summarizes the challenges faced for chronic wound treatment and specified factors responsible for delayed healing. Moreover, this review delivers a detailed discussion on available polymeric materials (alginate, chitosan, hyaluronic acid, collagen, polyurethane, cellulose, dextran, gelatin, silk, and polyaniline), their functional characteristics, and usage as chronic wound healing agents for polymeric wound dressing development. Incorporation and comparison of the research studies for their thermal behavior, structural analysis, and microscopic studies by Fourier transform infrared spectroscopy, thermogravimetric analysis and scanning electron microscopy, respectively and swelling studies of different polymeric materials are discussed. Additionally, studies of anatomy cum physiology of wound healing, pathophysiology, tissue engineering and advance healing management approaches makes the content of this review a significant tool for future studies on chronic wounds healing by polymeric wound dressings. In this review, polymeric wound dressings have been explained in terms of their structures, function, chemistry, and key characteristics. These features are directly linked to the polymeric systems' potential in the management of chronic wounds. These polymeric systems have gained promising success in solving real word global health problems. More recently, innovative approaches to fabricate the polymer dressings have been introduced, but their commercial, sustainable, and high-scale production largely remains unexplored. This review also summarizes the promises of polymeric wound dressings and provides a future perspective on how the clinical and commercial landscape could potentially be propelled by utilizing polymers in wound care management.
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Materiais Biocompatíveis , Pé Diabético , Bandagens , Pé Diabético/tratamento farmacológico , Humanos , Polímeros , CicatrizaçãoRESUMO
Fresh and clean water is consistently depleting and becoming a serious problem with rapid increases in population, so seawater desalination technology has captured global attention. For an efficient desalination process, this work proposes a novel, nanofibrous, thin-film composite membrane (NF-TFC) based on the deposition of the nanofibrous active layer of a blend of chitosan (CS) and poly (vinylpyrrolidone) (PVP) crosslinked with maleic acid on a 3-triethoxysilylpropylamine functionalized cellulose acetate substrate. FTIR analysis demonstrated the development of chemical and physical interactions and confirmed the incorporation of functional groups present in the NF-TFC. Scanning electron microscopy (SEM) micrographs depict the fibrous structure of the active layers. The reverse osmosis (RO) desalination characteristics of NF-TFC membranes are elevated by increasing the concentration of the crosslinker in a CS/PVP blend. Cellulose acetate (CA)-S4 attained an optimal salt rejection of 98.3% and permeation flux of 42.9 L/m2h, suggesting that the NF-TFC membranes could be favorable for seawater desalination.
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Quitosana/química , Maleatos/química , Nanofibras/química , Purificação da Água , Filtração , Humanos , Osmose , Água do Mar/química , Água/químicaRESUMO
Controlled drug delivery is a prime stratagem for minimizing both the frequency of therapeutic administration as well as systematic side effects with high drug content. One of the extensively studied approaches for controlling medicament delivery is the encapsulation of drug within polymer chains which sluggish the release on the basis of its crosslinked network. Recent advances in biomedical field have led to the fabrication of chitosan (CS) based biocompatible and biodegradable hydrogels for controlled delivery of encapsulated drug. In this study, CS-PVP based hydrogels are fabricated by varying the concentration of 3-glycidyloxypropyl trimethoxysilane (GPTMS) via solution casting technique. Swelling indices of prepared hydrogel samples were determined in different media including distilled water, different pH and electrolyte solutions. FTIR, TGA and WAXRD are conducted to evaluate the structural, thermal and crystalline properties of prepared hydrogels, respectively. Porosity (71%), hydrophilicity (55°) and mechanical properties (97.56 MPa of UTS and 85.23% E%) were investigated for the fabricated samples. Extensively in vitro biodegradation, antimicrobial performance and cytotoxicity were evaluated for these hydrogels. The drug release analysis was carried out to examine the release response of encapsulated iodopovidone at physiological conditions. These results tender a strategy for the design of structural hydrogel with different crosslinking mechanism like physical and covalent interactions. These insights obviate the demand for encapsulation and offer promising and translatable strategies for more effective release of drugs.
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Quitosana/química , Portadores de Fármacos/química , Sistemas de Liberação de Medicamentos , Hidrogéis/química , Povidona-Iodo/administração & dosagem , Reagentes de Ligações Cruzadas/química , Preparações de Ação Retardada , Liberação Controlada de Fármacos , Eletrólitos , Humanos , Concentração de Íons de Hidrogênio , Interações Hidrofóbicas e Hidrofílicas , Porosidade , Difração de Raios XRESUMO
Inflammation is a key challenge in the treatment of chronic diseases. Spurred by topical advancement in polymer chemistry and drug delivery, hydrogels that release a drug in temporal, spatial and dosage controlled fashion have been trendy. This research focused on the fabrication of hydrogels with controlled drug release properties to control inflammation. Chitosan and polyvinyl pyrrolidone were used as base polymers and crosslinked with epichlorohydrin to form hydrogel films by solution casting technique. Prepared hydrogels were analyzed by swelling analysis in deionized water, buffer and electrolyte solutions and gel fraction. Functional groups confirmation and development of new covalent and hydrogen bonds, thermal stability (28.49%) and crystallinity were evaluated by FTIR, TGA and WAXRD, respectively. Rheological properties including gel strength and yield stress, elasticity (2309 MPa), porosity (75%) and hydrophilicity (73°) of prepared hydrogels were also evaluated. In vitro studies confirmed that prepared hydrogels have good biodegradability, excellent antimicrobial property and admirable cytotoxicity. Drug release profile (87.56% in 130 min) along with the drug encapsulation efficiency (84%) of prepared hydrogels was also studied. These results paved the path towards the development of hydrogels that can release the drugs with desired temporal patterns.
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Artemia/efeitos dos fármacos , Quitosana/química , Diclofenaco/química , Sistemas de Liberação de Medicamentos/métodos , Escherichia coli/efeitos dos fármacos , Hidrogéis/química , Animais , Reagentes de Ligações Cruzadas/química , Preparações de Ação Retardada/química , Portadores de Fármacos/química , Liberação Controlada de Fármacos , Elasticidade , Epicloroidrina/química , Hidrogéis/síntese química , Ligação de Hidrogênio , Interações Hidrofóbicas e Hidrofílicas , Inflamação , Microscopia Eletrônica de Varredura , Porosidade , Povidona/química , Reologia , Espectroscopia de Infravermelho com Transformada de Fourier , Água/química , Difração de Raios XRESUMO
Biopolymers have paramount importance in pharmaceutical applications and blended biopolymers have shown promising properties versus individual counterparts. In view of excellent performance of blended biopolymers, a novel series of blended membranes based on chitosan, guar gum and polyvinyl alcohol (CS/GG/PVA) were prepared by solution casting technique. The membranes were synthesized at different ratios of GG and CS, while keeping PVA constant. The surface morphology, structure, interaction of polymers and water absorbing capacity were determined with scanning electron microscope (SEM), Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and swelling properties. FTIR exhibited intermolecular bonding between the biopolymers used for membranes preparation. SEM analysis revealed that the surface morphology depends upon the various ratios of polymers. The swelling pattern has shown that the prepared membranes were hydrophilic in nature. Results revealed that the chitosan and guar gum based ternary blends with polyvinyl alcohol have potential for controlled drug release.
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Quitosana/química , Galactanos/química , Mananas/química , Gomas Vegetais/química , Álcool de Polivinil/química , Varredura Diferencial de Calorimetria , Preparações de Ação Retardada/síntese química , Preparações de Ação Retardada/química , Espectroscopia de Infravermelho com Transformada de FourierRESUMO
The novel silane crosslinked (TEOS) hydrogels based on eco-friendly biodegradable chitosan/guargum were prepared by blending with PEG to develop pH sensitive hydrogels (CGP) and achieved its hydrophilicity and target specificity for controlled release of drug. The crosslinker amount was varied to analyze its effect on the hydrogel properties and were characterized using FTIR, SEM, TGA, swelling studies (water, buffer and ionic solution) and in-vitro release of cephradine (CED). FTIR confirmed the presence of characteristic peaks and crosslinking between the components while SEM images showed the formation of clear micro- and macro-pores. The swelling behavior in water showed that compared to the controlled hydrogel, the crosslinked hydrogels revealed more swelling but a decrease in swelling with further increase in the amount of crosslinker was observed. The hydrogels showed low swelling at basic and neutral pH while maximum swelling was observed at acidic pH. This pH response made these hydrogels an ideal candidate for injectable controlled release. The CED was loaded on hydrogels and its release mechanism was studied in PBS, SGF and SIF which revealed that out of all hydrogels (CGP100, CGP150, CGP200 and CGP250), CGP100 has shown CED release of 85% in 130â¯min in PBS and 82.4% in SIF.
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Cefradina/química , Quitosana/química , Portadores de Fármacos/química , Galactanos/química , Hidrogéis/química , Mananas/química , Gomas Vegetais/química , Soluções Tampão , Preparações de Ação Retardada , Liberação Controlada de Fármacos , Concentração de Íons de Hidrogênio , Concentração Osmolar , Água/químicaRESUMO
Systematic administration of painkillers and anti-inflammatory drugs is routinely employed to minimize pain and bodily disorders. Controlled drug delivery has the potential to improve the outcomes of disorders by providing sustained exposure to efficacious drug concentrations. Herein, we report the fabrication of multi-responsive hydrogels using reactive and functional polymers such as chitosan and polyvinyl pyrrolidone by varying the concentration of a cleavable crosslinker, tetraethyl orthosilicate. The swelling indices of the hydrogels were evaluated in distilled water, solutions with different pH values and different electrolytes. FTIR, WAXRD and TGA were conducted to investigate the structures, crystallinities and thermal stabilities of the prepared multi-responsive hydrogels, respectively. The ultimate tensile strength and elongations at break of the fabricated hydrogels were investigated to assess their mechanical stability. Optical microscopy, biodegradation, antimicrobial and cytotoxicity analyses were further carried out to verify the magnified crosslinked and porous structures, biodegradabilities, biocompatibilities and toxic behaviour of the as-prepared hydrogels, respectively. Drug release analysis was conducted to evaluate their release behaviour in PBS, SGF, SIF and electrolyte solutions. The overall results indicate the successful development of novel, non-toxic and sustained drug deliverable hydrogels, which can be considered as a paramount success towards the fabrication of controlled drug delivery systems.
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In this work, cellulose acetate (CA) based thin film nanocomposite reverse osmosis (RO) membranes were fabricated using dissolution casting method by optimizing the CA/polyethylene glycol (CA/PEG-400) ratios for improved RO performance. The selectivity of optimized membrane was further enhanced by incorporating TiO2 (0-25â¯wt.%) nanoparticles. Fourier transform infrared spectroscopy (FTIR), thermogravimetric analyzer (TGA), scanning electron microscopy (SEM) and X-ray diffraction (XRD) were conducted to characterize control and modified membranes for the analysis of functional groups, thermal properties, morphology and structural investigation respectively. CP-2 of CA/PEG-400 (80/20) was selected for further modification with TiO2 nanoparticles. The maximum salt rejection (95.4%) was observed for the membrane having 15% TiO2 nanoparticles. Further escalation of TiO2 concentration resulted in the agglomeration of nanoparticles which subsequently decreased the permeation flux. The test results demonstrated that the modified membranes had higher salt rejection and chlorine resistance, lower degradation profile, successful inhibition of Escherichia coli growth and facilitating permeation flux compared to the control membrane.
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Novel pH-sensitive γ-irradiated low molecular weight (MW) chitosan (CS) (pre-irradiated) and poly (vinyl alcohol) (PVA) blended injectable hydrogels, crosslinked with varying concentrations of glycerol, were fabricated for drug delivery application. The effect of low MW irradiated CS on controlled drug release was evaluated to address the problem of higher viscosity and lower solubility of high MW CS. The FTIR spectra of hydrogels depicted the presence of all the incorporated functional groups and the developed interactions (physical and chemical). The surface morphology of hydrogels assessed by scanning electron microscope exhibited porous microstructure. All hydrogels were subjected to the swelling analysis in different media (water, buffer and electrolytes). The pH sensitive hydrogel samples exhibited less swelling at acidic and neutral pH while higher swelling at basic pH. CPG-0.5 showed the highest swelling at all pH media as compared to other hydrogel samples. CPG-1.0 was selected for the release analysis of drug because of its highest swelling (114.47%) in distilled water having neutral pH. It was loaded with model drug (Montelukast Sodium) during the preparation phase and studied for drug release capability. The in-vitro controlled release evaluation of hydrogel (CPG-1.0) was performed in SGF and SIF using UV-visible spectroscopy. The results confirmed their applications in injectable drug release systems as all the loaded drug was released in 30â¯min in SGF (pHâ¯-1.2) while the release of drug in SIF (pHâ¯-6.8) was in controlled manner (99.62% in 3â¯h). The improved antibacterial activity of these hydrogel films was owing to the fact that the γ-irradiated low MW CS has ruptured the bacterial cell and its metabolism more efficiently by inflowing in the cell.
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Acetatos/administração & dosagem , Quinolinas/administração & dosagem , Quitosana/administração & dosagem , Quitosana/química , Quitosana/efeitos da radiação , Reagentes de Ligações Cruzadas/farmacologia , Ciclopropanos , Preparações de Ação Retardada , Sistemas de Liberação de Medicamentos , Avaliação Pré-Clínica de Medicamentos , Liberação Controlada de Fármacos , Escherichia coli/efeitos dos fármacos , Raios gama , Glicerol/farmacologia , Hidrogéis/administração & dosagem , Hidrogéis/química , Hidrogéis/efeitos da radiação , Ligação de Hidrogênio , Concentração de Íons de Hidrogênio , Interações Hidrofóbicas e Hidrofílicas , Microscopia Eletrônica de Varredura , Peso Molecular , Álcool de Polivinil/administração & dosagem , Porosidade , Espectrofotometria Ultravioleta , Espectroscopia de Infravermelho com Transformada de Fourier , SulfetosRESUMO
Novel biodegradable films were prepared by blending guar gum, chitosan and poly (vinyl alcohol) having mint (ME) and grapefruit peel (GE) extracts and crosslinked with nontoxic tetraethoxysilane (TEOS). The co-concentration effect of TEOS with natural extracts on the films was studied. FTIR analysis confirmed the presence of incorporated components and the developed interactions among the polymer chains. The surface morphology of the films by SEM showed the hydrophilic character due to porous network structure. The films having both ME and GE with maximum amount of crosslinker (100µL), showed maximum swelling (58g/g) and stability while the optical properties showed increased protection against UV light. This film sample showed compact network structure which enhanced the ultimate tensile strength (40.03MPa) and elongation at break (104.8%). ME/GE conferred the antioxidant properties determined by radical scavenging activity and total phenolic contents (TPC) as ME films have greater TPC compared to GE films. The soil burial test exhibited the degradation of films rapidly (6days) confirming their strong microbial activity in soil. The lower water vapour transmission rate and water vapour permeability showed better shelf life; hence, these biodegradable films are environmental friendly and have potential for food and other packaging.
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Quitosana/química , Embalagem de Alimentos/métodos , Galactanos/química , Mananas/química , Extratos Vegetais/química , Gomas Vegetais/química , Silanos/química , Biodegradação Ambiental , Citrus paradisi/química , Reagentes de Ligações Cruzadas/química , Humanos , Membranas Artificiais , Mentha/química , Álcool de Polivinil/química , Porosidade , Vapor/análise , Resistência à Tração , Raios UltravioletaRESUMO
Silane crosslinked biopolymer based novel pH-responsive hydrogels were fabricated by blending the cationic (chitosan) and anionic (alginate) polymers with poly(vinyl alcohol). Tetraethoxysilane (TEOS) was used, as a crosslinker in different amounts due to its nonhazardous nature, to study its impact on physical and chemical properties of the prepared injectable hydrogels along with the controlled release of drug. The swelling response of the prepared hydrogels was examined in different solvent media which exhibited decreased swelling ratio with increase in the amount of TEOS. All the fabricated hydrogels represented highest swelling at acidic pH while low swelling at basic and neutral pH. This specific pH sensitive behavior at pH 7 made them an appropriate candidate for the injectable controlled drug delivery in which Neomycin Sulfate (NMS) was successfully loaded on suitable hydrogel (comprising 50µL TEOS) to study its release mechanism. The results revealed that in simulated gastric fluid (SGF), hydrogel released the entire drug (NMS) in initial 30min while in simulated intestinal fluid (SIF), NMS was released in a controlled way up to 83% in 80min. These results endorsed that the hydrogels could be practiced as a smart intelligent material for injectable controlled drug delivery as well as for other biomedical applications at physiological pH.
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Portadores de Fármacos/química , Hidrogéis/química , Neomicina/química , Silanos/química , Antibacterianos/química , Antibacterianos/farmacologia , Antibacterianos/toxicidade , Soluções Tampão , Preparações de Ação Retardada , Portadores de Fármacos/farmacologia , Portadores de Fármacos/toxicidade , Células HeLa , Humanos , Hidrogéis/farmacologia , Hidrogéis/toxicidade , Injeções , Água/químicaRESUMO
Novel silane crosslinked tough hydrogel scaffolds were prepared using chitosan (CS) and polyvinyl alcohol (PVA) to give network structure and scaffolds properties. The influence of crosslinking and PVA concentration on scaffolds were studied. Fourier transform infrared spectroscopy (FTIR) spectroscopy confirmed the presence of incorporated components. Tensile strength (TS) and fracture strain analysis of scaffolds were detected owing to the mutual effect of chemically and physically crosslinked network. Tough hydrogel scaffolds having 90% CS and 10% PVA exhibited TS of 49.18MPa and 10.15% elongation at break. The contact angle is less than 90° exhibited the hydrophilic nature of the scaffold. X-ray diffraction analysis (XRD) indicated the characteristics peaks fitting to CS and PVA and increase in the crystallinity of scaffolds. Cytotoxicity of scaffolds with different human fibroblast cell lines (F121, F192 and F84) for indirect method and human dermal fibroblast cell lines (F121) for direct method was evaluated. This indicated that these biomaterials were non-toxic, viable to the used cell lines, helpful in the growth of these cells and did not discharge toxic material damaging to the living cells.
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Quitosana , Fibroblastos/metabolismo , Hidrogéis , Teste de Materiais , Álcool de Polivinil , Alicerces Teciduais/química , Linhagem Celular , Quitosana/química , Quitosana/farmacologia , Humanos , Hidrogéis/química , Hidrogéis/farmacologia , Álcool de Polivinil/química , Álcool de Polivinil/farmacologiaRESUMO
Graphene oxide (GO) was indigenously synthesized from graphite using standard Hummers method. Chitosan-graphene oxide green composite films were fabricated by mixing aqueous solution of chitosan and GO using dilute acetic acid as a solvent for chitosan. Chitosan of different viscosity and calculated molecular weight was used keeping amount of GO constant in each composite film. The structural properties, thermal stability and mechanical properties of the composite films were investigated using Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric analysis (TGA) and tensile test. FTIR studies revealed the successful synthesis of GO from graphite powder and it was confirmed that homogenous blending of chitosan and GO was promising due to oxygenated functional groups on the surface of GO. XRD indicated effective conversion of graphite to GO as its strong peak observed at 11.06° as compared to pristine graphite which appeared at 26°. Moreover, mechanical analysis confirmed the effect of molecular weight on the mechanical properties of chitosan-GO composites showing that higher molecular weight chitosan composite (GOCC-1000) showed best strength (higher than 3GPa) compared to other composite films. Thermal stability of GOCC-1000 was enhanced for which residual content increased up to 56% as compared to the thermal stability of GOCC-200 whose residue was restricted to only 24%. The morphological analysis of the composites sheets by SEM was smooth having dense structure and showed excellent interaction, miscibility, compatibility and dispersion of GO with chitosan. The prepared composite films find their applications as biomaterials in different biomedical fields.
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Materiais Biocompatíveis/síntese química , Quitosana/química , Grafite/química , Óxidos/química , Difração de Raios XRESUMO
Selected properties of chitosan (CS) and poly(vinyl alcohol) (PVA) blends crosslinked by tetraethoxysilane (TEOS) were studied. XRD analysis showed characteristics peak at 22.5° attributed to the crystalline structure of CS and PVA. DSC thermograms unveiled the quantitative determination of free, intermediate and bound water in the blends. Tensile strength and fracture strain of blends were observed due to the combined effect of physically and chemically crosslinked network structures. The decrease in water contact angle indorsed the hydrophilic performance while the storage modulus G' and loss modulus Gâ³ was decreased as the temperature was increased exhibited the viscoelastic property of the blends. The fabricated blends can be employed for drug delivery systems, tissue engineering and other biomedical applications.