RESUMO
Magnetic sensors are key elements in many industrial, security, military, and biomedical applications. Heusler alloys are promising materials for magnetic sensor applications due to their high spin polarization and tunable magnetic properties. The dynamic field range of magnetic sensors is strongly related to the perpendicular magnetic anisotropy (PMA). By tuning the PMA, it is possible to modify the sensing direction, sensitivity and even the accuracy of the magnetic sensors. Here, we report the tuning of PMA in a Co2MnGa Heusler alloy film via argon (Ar) ion irradiation. MgO/Co2MnGa/Pd films with an initial PMA were irradiated with 30 keV 40Ar+ ions with fluences (ions·cm-2) between 1 × 1013 and 1 × 1015 Ar·cm-2, which corresponds to displacement per atom values between 0.17 and 17, estimated from Monte-Carlo-based simulations. The magneto optical and magnetization results showed that the effective anisotropy energy (Keff) decreased from ~153 kJ·m-3 for the un-irradiated film to ~14 kJ·m-3 for the 1 × 1014 Ar·cm-2 irradiated film. The reduced Keff and PMA are attributed to ion-irradiation-induced interface intermixing that decreased the interfacial anisotropy. These results demonstrate that ion irradiation is a promising technique for shaping the PMA of Co2MnGa Heusler alloy for magnetic sensor applications.
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A novel adsorbent was prepared by blending chitosan (CS) and acrylic acid (AA) while using formaldehyde as a cross linker in the form of hydrogel beads. The adsorption properties of these hydrogel beads for the removal of toxic metal ions (Pb2+ and Cd2+) from aqueous solutions were evaluated. The hydrogel beads have a 3D macro-porous structure whose -NH2 groups were considered to be the dominant binding specie for Cd and Pb ions. The equilibrium adsorption capacity (qe) of beads was significantly affected by the mass ratio of sorbent and sorbate. The percentage removal of Cd and Pb ions was observed to be enhanced with the increase in sorbate concentration. The hydrogel beads maintained good adsorption properties at adsorption-desorption equilibrium. The Langmuir and Freundlich models were used to elaborate the isotherms as well as isotherm constants. Adsorption isothermal data is well explained by the Freundlich model. The data of experimental kinetics is interrelated with the second-order kinetic model, which showed that the chemical sorption phenomenon is the rate limiting step. The results of intraparticle diffusion model described the adsorption process occurred on a porous substance that proved chitosan/Formaldehyde beads to be the favorable adsorbent.
Assuntos
Quitosana , Poluentes Químicos da Água , Purificação da Água , Adsorção , Cádmio , Quitosana/química , Formaldeído , Hidrogéis/química , Concentração de Íons de Hidrogênio , Íons , Cinética , Chumbo , Porosidade , Água/química , Poluentes Químicos da Água/análise , Purificação da Água/métodosRESUMO
Chitosan and polyethylene glycol (PEG-600) membranes were synthesized and crosslinked with 3-aminopropyltriethoxysilane (APTES). The main purpose of this research work is to synthesize RO membranes which can be used to provide desalinated water for drinking, industrial and agricultural purposes. Hydrogen bonding between chitosan and PEG was confirmed by displacement of the hydroxyl absorption peak at 3237 cm-1 in pure chitosan to lower values in crosslinked membranes by using FTIR. Dynamic mechanical analysis revealed that PEG lowers Tg of the modified membranes vs. pure chitosan from 128.5 °C in control to 120 °C in CS-PEG5. SEM results highlighted porous and anisotropic structure of crosslinked membranes. As the amount of PEG was increased, hydrophilicity of membranes was increased and water absorption increased up to a maximum of 67.34%. Permeation data showed that flux and salt rejection value of the modified membranes was increased up to a maximum of 80% and 40.4%, respectively. Modified films have antibacterial properties against Escherichia coli as compared to control membranes.
Assuntos
Quitosana/química , Filtração/métodos , Membranas Artificiais , Polietilenoglicóis/química , Propilaminas/química , Silanos/química , Antibacterianos/farmacologia , Reagentes de Ligações Cruzadas/química , Escherichia coli/efeitos dos fármacos , Ligação de Hidrogênio , Interações Hidrofóbicas e Hidrofílicas , Microscopia Eletrônica de Varredura , Osmose , Permeabilidade , Polímeros/química , Polímeros/farmacologia , Porosidade , Espectroscopia de Infravermelho com Transformada de Fourier , Propriedades de Superfície , Água/químicaRESUMO
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.
Assuntos
Quitosana/química , Maleatos/química , Nanofibras/química , Purificação da Água , Filtração , Humanos , Osmose , Água do Mar/química , Água/químicaRESUMO
This study investigated the adsorption of Oxytetracycline (OTC) from pharmaceutical wastewater using a kappa carrageenan based hydrogel (KPB). The aim of the present study was to explore the potential of KPB for long-term pharmaceutical wastewater treatment. A sustainable adsorbent was developed to address oxytetracycline (OTC) contamination. The hydrogel's structural and adsorption characteristics were examined using various techniques like Scanning Electron Microscope (SEM), Fourier Transform Infrared (FTIR), X-ray powder diffraction (XRD), and kinetic models. The results revealed considerable changes in the vibrational modes and adsorption bands of the hydrogel, suggesting the effective functionalization of Bentonite nano-clay. Kappa carrageenan based hydrogel achieved the maximum removal (98.5%) of OTC at concerntration of 40 mg/L, pH 8, cotact time of 140 min and adsorbent dose of 0.1 g (KPB-3). Adsorption of OTC increased up to 99% with increasing initial concentrations. The study achieved 95% adsorption capacity for OTC using a KPB film at a concentration of 20 mg/L and a 0.1 g adsorbent dose within 60 min. It also revealed that chemisorptions processes outperform physical adsorption. The Pseudo-Second-Order model, which emphasized the importance of chemical adsorption in the removal process, is better suited to represent the adsorption behavior. Excellent matches were found that R2 = 0.99 for KPB-3, R2 = 0.984 for KPB-2 and R2 = 0.989 for KPB-1 indicated strong chemical bonding interactions. Statisctical analysis (ANOVA) was performed using SPSS (version 25) and it was found that pH and concentration had significant influence on OTC adsorption by the hydrogel, with p-values less than 0.05. The study identified that a Kappa carrageenan-based hydrogel with bentonite nano-clay and polyvinyl alcohol (PVA) can efficiently remove OTC from pharmaceutical effluent, with a p-value of 0.054, but weak positive linear associations with pH, temperature, and contact time. This research contributed to sustainable wastewater treatment and environmental engineering.
Assuntos
Carragenina , Hidrogéis , Oxitetraciclina , Águas Residuárias , Poluentes Químicos da Água , Purificação da Água , Oxitetraciclina/química , Oxitetraciclina/isolamento & purificação , Carragenina/química , Águas Residuárias/química , Hidrogéis/química , Poluentes Químicos da Água/química , Poluentes Químicos da Água/isolamento & purificação , Adsorção , Purificação da Água/métodos , Cinética , Concentração de Íons de Hidrogênio , Espectroscopia de Infravermelho com Transformada de Fourier , Antibacterianos/químicaRESUMO
The present study was aimed at synthesis of polymeric hydrogels for controlled boron (B) release, as B deficiency is a major factor that decreases crops yield. Thus, graphene oxide incorporated guar gum and poly (ethylene glycol) hydrogels were prepared using the Solution Casting method for boron release. 3-Glycidyloxypropyl trimethoxysilane (GLYMOL) was used as a cross-linker. Characterizations of hydrogels were carried out by Fourier Transform Infrared Spectroscopy (FTIR), Thermo-Gravimetric Analysis and Scanning Electron scope. The FTIR outcomes confirmed the existence of functional groups, bindings and development of hydrogel frameworks from incorporated components. The quantity of GLYMOL directly increased the thermal stability and water retention but decreased the swelling %. The maximum swelling for the hydrogel formulations was observed at pH 7. The addition of GLYMOL changed the diffusion from quasi-Fickcian to non-Fickcian diffusion. The maximum swelling quantities of 3822% and 3342% were exhibited by GPP (control) and GPP-8 in distilled water, respectively. Boron release was determined in distilled water and sandy soil by azomethine-H test using UV-Visible spectrophotometer while 85.11% and 73.65% boron was released from BGPP-16, respectively. In short, water retentive, water holding capacities, swelling performances, biodegradability and swelling/deswelling features would offer an ideal platform for boron release in sustained agricultural applications.
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Chitosan (Cs) based biomaterials seem to be indispensable for neovasculogenesis and angiogenesis that ensure accelerated wound healing. Cs/poly (vinyl alcohol) (PVA) bio-constructs were cross-linked and investigated with varying concentrations of aminopropyltriethoxysilane (APTES). This study comprised of three phases: fabrication of hydrogels, characterization, assessment of angiogenic potential along with toxico-pathological effects, wound healing efficacy in chick and mice, respectively. The hydrogels were characterized by FTIR, SEM and TGA and the swelling response was examined in different solvents. The hydrogels swelling ratio was decreased with increasing amount of APTES, showed the highest swelling at acidic and basic pH while low swelling at neutral pH. Chorioallantoic membranes (CAM) assay was performed to study in-vivo angiogenesis, toxicological, morphological, biochemical and histological analyses in developing chicks. The results showed remarkably improved angiogenesis with little deviations in morphological, histological features and liver enzymes of chick embryos at higher concentrations of APTES. Besides, full thickness wounds were excised on mice dorsolateral skin to assess the wound healing. The rate of wound size reduction was significantly higher after topical application of hydrogels with elevated levels of crosslinker. Hence, the hydrogels showed enhanced angiogenesis, accelerated wound healing with little or no observable in-vivo toxicity.
Assuntos
Quitosana , Animais , Embrião de Galinha , Quitosana/química , Quitosana/farmacologia , Hidrogéis/química , Hidrogéis/farmacologia , Camundongos , Álcool de Polivinil/química , Álcool de Polivinil/farmacologia , Propilaminas , Silanos , CicatrizaçãoRESUMO
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.
Assuntos
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
Mixed matrix membranes (MMMs) of cellulose acetate/poly(vinylpyrrolidone) (CA/PVP) infused with acid functionalized multiwall carbon nanotubes (f-MWCNTs) were fabricated by an immersion phase separation technique for hemodialysis application. Membranes were characterized using FTIR, water uptake, contact angle, TGA, DMA and SEM analysis. The FTIR was used to confirm the bonding interaction between CA/PVP membrane matrix and f-MWCNTs. Upon addition of f-MWCNTs, TGA thermograms and glass transition temperature indicated improved thermal stability of MMMs. The surface morphological analysis demonstrated revealed uniform distribution of f-MWCNTs and asymmetric membrane structure. The water uptake and contact angle confirmed that hydrophilicity was increased after incorporation of f-MWCNTs. The membranes demonstrated enhancement in water permeate flux, bovine serum albumin (BSA) rejection with the infusion of f-MWCNTs; whereas BSA based anti-fouling analysis using flux recovery ratio test shown up to 8.4% improvement. The urea and creatinine clearance performance of MMMs were evaluated by dialysis experiment. It has been found that f-MWCNTs integrated membranes demonstrated the higher urea and creatinine clearance with increase of 12.6% and 10.5% in comparison to the neat CA/PVP membrane. Thus, the prepared CA/PVP membranes embedded with f-MWCNTs can be employed for wide range of dialysis applications.
Assuntos
Celulose/análogos & derivados , Membranas Artificiais , Nanotubos de Carbono/química , Povidona/química , Diálise Renal/instrumentação , Celulose/química , Creatinina/química , Interações Hidrofóbicas e Hidrofílicas , Diálise Renal/métodosRESUMO
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.
Assuntos
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
Diffusion dialysis (DD) using anion exchange membranes (AEM) is an effective process for acid recovery and requires the preparation of suitable materials for AEMs, characterized by unique ions transport properties. In this work, novel AEMs composed of quaternized diaminobutane (QDAB) and poly(vinyl alcohol) (PVA) were cross-linked by tetraethoxysilane (TEOS) via the sol-gel process. The prepared AEMs were systematically characterized by Fourier-transform infrared (FTIR) spectroscopy, ion-exchange capacity (IEC) analysis, thermo gravimetric analysis (TGA), water uptake, linear expansion ratio (LER), and mechanical strength determination, scanning electron microscopy (SEM), and DD performance analysis for acid recovery using a hydrochloric acid/iron chloride (HCl/FeCl2) aqueous mixture and varying the QDAB content. The prepared AEMs exhibited IEC values between 0.86 and 1.46 mmol/g, water uptake values within 71.3 and 47.8%, moderate thermal stability, tensile strength values in the range of 26.1 to 41.7 MPa, and elongation from 68.2 to 204.6%. The dialysis coefficient values were between 0.0186 and 0.0295 m/h, whereas the separation factors range was 24.7-44.1 at 25 °C. The prepared membranes have great potential for acid recovery via diffusion dialysis.
RESUMO
A series of polymeric membranes were synthesized by blending polyurethane with sodium alginate (0.2, 0.4, 0.6, 0.8 and 1.0%). The structural, morphological and thermal properties of the membranes were examined by FTIR, SEM, AFM and TGA, respectively. Performance evaluation (salt rejection and flux) was assessed through reverse osmosis technique (RO). The FTIR spectra of membranes confirmed extensive hydrogen bonding (3350 cm-1). The SEM and AFM analyses supported a progressively rising surface roughness of blended membranes. The hydrophilicity, crosslinking density and thermal stability of the membranes were improved with an increase in alginate content. The capability of salt (NaCl and MgCl2) rejection was improved with alginate up to 0.8%. In addition, the rejection of divalent ions was better than monovalent ions (94 ± 0.96% for NaCl and 98 ± 0.98% for MgCl2). The blended membranes ascertained an effective chlorine resistivity. The antibacterial activity was also promising, which enhanced with the alginate content in the membrane. The sodium alginate blended membrane with polyurethane proved to be an efficient approach to develop the blended membranes with tunable properties for water desalination.
Assuntos
Alginatos/química , Anti-Infecciosos/química , Membranas Artificiais , Poliuretanos/química , Anti-Infecciosos/farmacologia , Bacillus/efeitos dos fármacos , Cloro/química , Géis/química , Concentração Osmolar , OsmoseRESUMO
Chitosan (biopolymer) and polyvinyl pyrolidone (PVP) with aminopropyletriethoxy silane (cross linker) based hydrogels were prepared and tested for controlled drug release. The drug release and kinetics were studied as a function of pH. Formulations were characterized by Fourier Transform Infrared (FTIR) and Thermogravimetric (TGA) analysis and TAP 32 hydrogel formulation was the most stable and hydrogel samples showed promising antibacterial activity against E. coli strain. The maximum swelling (4386%) was observed for TAP 32 formulation in distilled water, which was decreased with the concentration of ions. The diffusion exponent (n) values of all hydrogel formulations were recorded to be <0.5, which is an indication of Quasi-Fickian diffusion. The maximum swelling was observed at pHâ¯2 and decreased at higher pH. The pH sensitivity of hydrogels found to be promising for their use in drug delivery, which was tested for cefixime drug. Drug release of 81.6% was observed for the period of 12â¯h in a simulated gastric fluid (SGF). The values of R2 for zero order, first order, Higuchi, Hixson, Korsmeyer-Peppas and Baker-Lonsdale were 0.97, 0.9818, 0.99, 0.99, 0.88 and 0.80, respectively. The hydrogels based on chitosan and PVP revealed potential for controlled cefixime drug release in gastric pH medium.
Assuntos
Antibacterianos/administração & dosagem , Cefixima/administração & dosagem , Quitosana/química , Hidrogéis/química , Antibacterianos/química , Cefixima/química , Preparações de Ação Retardada , Difusão , Liberação Controlada de Fármacos , Escherichia coli/efeitos dos fármacos , Concentração de Íons de Hidrogênio , Cinética , Espectroscopia de Infravermelho com Transformada de Fourier , TermogravimetriaRESUMO
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.
Assuntos
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
The controlled release of drug from drug carrier has been a point of concern for the researchers to ensure the bioavailability of drug with reduced side effects. The formulation in this study is based upon biopolymers; carrageenan (CG), sodium alginate (SA) and various molecular weights of polyethylene glycol (PEG), cross-linked with (3-Aminopropyl)triethoxysilane, APTES for the sustained release of model drug (lidocaine). The physicochemical properties of the formulated hydrogel blends include bonding pattern (using Fourier Transform Infra-Red Spectroscopy (FTIR), Thermogravimetric analysis (TGA), X-ray diffraction (XRD), swelling study, antimicrobial activity and morphology of hydrogel films was analyzed by scanning electron microscopy (SEM). The as-prepared hydrogels show an improved cell compatibility against 3T3 cell line as well as cell proliferation and kinetics of drug release showed that these hydrogels are potential for controlled release of lidocaine, a numbing agent. GAP 60 exhibited maximum swelling percent (910%) and was employed to load the drug. By using in vitro model, the drug release was studied in PBS solution. Non-Fickian and other kinetic models (Zero order, Higuchi, Hixson, Korsmeyer Peppas and Baker-Lonsdale) for diffusion were followed in results. The improved properties showed that the formulated hydrogels can easily be used for the sustain drug release studies.
Assuntos
Alginatos/química , Carragenina/química , Liberação Controlada de Fármacos , Hidrogéis/química , Lidocaína/farmacologia , Células 3T3 , Animais , Anti-Infecciosos/farmacologia , Soluções Tampão , Sobrevivência Celular/efeitos dos fármacos , Preparações de Ação Retardada/farmacologia , Escherichia coli/efeitos dos fármacos , Hidrogéis/síntese química , Concentração de Íons de Hidrogênio , Íons , Cinética , Camundongos , Testes de Sensibilidade Microbiana , Polietilenoglicóis/química , Soluções , Espectroscopia de Infravermelho com Transformada de Fourier , Termogravimetria , Fatores de Tempo , Difração de Raios XRESUMO
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.
Assuntos
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
Stimuli responsive chitosan (CS) and poly (N-vinyl-2-pyrrolidone) (PVP) have attained hydrogel properties in the presence of 74% neutralized poly acrylic acid (PAA) which can be exploited for wound healing applications. The FTIR spectra confirmed the presence of all specific functional groups and the developed interactions in the hydrogels. The thermal analysis explained that the hydrogel samples are thermally more stable than individual chitosan and PVP. The antimicrobial analysis revealed that all the samples show antibacterial activity against E. coli and the biodegradation analysis is performed to confirm the hydrogels degradation. The hydrogels showed enhanced responsive swelling behavior against different media depending upon the amount of PVP. The %age swelling in water is decreased with the increase in the amount of PVP. The most considerable swelling behavior is observed against pH, as they manifested low swelling at acidic pH and high swelling at neutral pH while at pH 8, the prominent values are obtained. This distinctive behavior of hydrogels and their biocompatibility made them pertinent to drug delivery and their release profile is examined spectrophotometrically using silver sulfadiazine (antibiotic for burnt wounds) showed 91.2% of drug release for a period of 1 h in phosphate buffer saline (PBS) in a consistent and controlled manner.
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Kappa carrageenan was used to prepare hydrogels having novel compositions with poly(vinyl alcohol) (PVA) and a crosslinker (3-aminopropyl)triethoxysilane (APTES). FTIR was used to confirm the structure and composition of hydrogels. The swelling behavior of hydrogels was studied under different conditions of pH and electrolytic aqueous media. The most efficient swelling result (200%) was observed by the sample containing a low fraction of crosslinker. It also showed different swelling responses in different pH solutions that made it suitable for drug delivery. Thermogravimetric analysis (TGA) illustrated that with the increase in crosslinker amount, the stability of hydrogel was increased. The biodegradation analysis of the hydrogels exhibited the break down by various enzymes into small chain polysaccharides that further broke down in the metabolic pathways. It was revealed that all the hydrogel samples showed strong antibacterial activity against S. aureus and a little against E. coli. Cephradine was used as a model drug and its in vitro release was studied in simulated intestinal fluids (SIF). This release account of the cephradine demonstrated that the release of the drug increased as the time and pH increased, reaching its maximum amount of 85.5% after 7.5 h.
RESUMO
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.
Assuntos
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.