Crosslinked Chitosan Membrane Research Articles

A novel chitosan-glutamic acid membrane for multi-pollutant amputation: Investigational and RSM optimizations

The novel glutamic acid crosslinked chitosan membrane (CsG) was fabricated and tested for its adsorption capabilities for the removal of multiple pollutants like Cr (VI), cyanide, fluoride and diclofenac sodium from wastewater. This fabricated CsG membrane was characterized by various techniques like FT-IR, SEM, EDX and XRD, BET to assess its structural, compositional and morphological properties. The working parameters studied by batch experiments were solution pH, CsG dose, contact time, pollutant concentration and solution temperature. The CsG membrane exhibited maximum adsorption capacity of 410.7 mg/g, 310.2 mg/g, 14.3 mg/g, 132.7 mg/g for Cr (VI), cyanide, fluoride and diclofenac respectively. The validation of the operational parameters was performed by Response Surface Methodology (RSM). The experimental data fitted well with Langmuir isotherm model and followed pseudo second order kinetics for all the four targeted contaminants. The spontaneity of the process was checked by thermodynamics studies. The high partition coefficients of 7669 L/kg Cr(VI), 23,309 L/kg (CN−), 649 L/kg (F−) and 2613 L/kg (DFC) are the indicators of excellent attractive interaction between CsG membrane and target toxicants. The CsG membrane showed efficient regenerative adsorption properties up to 5 adsorption-desorption cycles. Overall, the developed novel CsG membrane promised as an effective material for the removal of multiple number of pollutants from water.

SINTESIS DAN MODIFIKASI STRUKTUR DAN PORI MEMBRAN KITOSAN TERCROSSLINK UNTUK STERILISASI MEDIA PERTUMBUHAN BAKTERI

Many mass-transfer applications have used chitosan membrane in separation processes. This research applied crosslinked chitosan membrane to sterillize bacterial growth media. Chitosan membranes having 79 % DD were produced by casting and drying chitosan solution. The images of the membrane were characterized by SEM and other characterizations such as permeability, permselectivity and tensile strength were investigated. The flux increased with longer submersion period but the rejection decreased. Otherwise, the flux decreased and rejection increased in line with an increase in curing temperature. Tensile strength increased with the increase of submersion period and curing temperature. The optimum conditions of crosslinking process are 2 hours of submersion periods and curing temperature at 90 oC. It gives flux 5.8930 L/jam.m2, rejection 97.47 % and tensile strength 49640 kN/m2

Development of crosslinked chitosan membrane networks for uptake of copper and nickel metal ions

Development of crosslinked chitosan membrane networks for uptake of copper and nickel metal ions

Facile synthesis and characterization of cross-linked chitosan quaternary ammonium salt membrane for antibacterial coating of piezoelectric sensors

Novel cross-linked chitosan quaternary ammonium salt (CHACC) membranes were successfully prepared by the reaction of chitosan quaternary ammonium salt (HACC) and epichlorohydrin. The structures and morphologies of the CHACC membranes were characterized. The water stability and antibacterial efficiency of CHACC membranes were investigated by the equilibrium swelling method, the plate count method and minimum inhibitory concentration (MIC) test, respectively. Further, an antibacterial piezoelectric sensor with a multilayered structure was prepared by attaching the CHACC membrane to a poly(vinylidenefluoride‑co‑trifluoroethylene) (PVDF-TrFE) based sensor. The piezoelectrical properties of PVDF-TrFE based sensors coated with CHACC were investigated. The results showed that the CHACC-4 with a three-dimensional network structure exhibited best water stability (193% of swelling degree) and antibacterial properties (antibacterial rate>99%), and the MIC of CHACC against E. coli, S. aureus and P. aeruginosa was 40, 320 and 640μg/mL, respectively. Additionally, the coating of CHACC-4 had no adverse effect on the piezoelectric properties of the prepared sensor. The fabricated multilayer sensor has potential applications in the field of wearable devices.

Preparation of Citric Acid Crosslinked Chitosan/Poly(Vinyl Alcohol) Blend Membranes for Creatinine Transport

Preparation of membrane using crosslinking reaction between chitosan and citric acid showed that functional group modification increased the number of active carrier groups which lead to better transport capacity of the membrane. In addition, the substitution of the carboxyl group increased creatinine permeation of chitosan membrane. The transport capacity of citric acid crosslinked chitosan membrane for creatinine was found to be 6.3 mg/L. The presence of cyanocobalamin slightly hindered the transport of creatinine although compounds did not able to pass through citric acid crosslinked chitosan/poly(vinyl alcohol) blend membrane, as compounds no found in the acceptor phase.

Modification of crosslinked chitosan membrane using NaY zeolite for pervaporation separation of water–isopropanol mixtures

The blocked diisocyanate crosslinked chitosan membrane was modified by incorporating different mass% of NaY zeolite. The physico-chemical properties of resulting composite membranes were studied using Fourier transform infrared spectroscopy (FTIR), wide-angle X-ray diffraction (WAXD), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and scanning electron microscopy (SEM). The mechanical properties of the membranes were studied using universal testing machine (UTM). After measuring the equilibrium swelling, membranes were subjected to pervaporation for separation of water–isopropanol mixtures. Both flux and selectivity were increased with increasing NaY zeolite content in the membranes. The membrane containing 40 mass% of NaY zeolite exhibited the highest separation selectivity of 11,241 with a flux of 11.37×10−2kg/m2h for 10 mass% of water in the feed. The total flux and flux of water are almost overlapping each other, suggesting that these membranes could be effectively used to break the azeotropic point of water–isopropanol mixture. From the temperature dependent diffusion and permeation values, the Arrhenius activation parameters were estimated. All the composite membranes exhibited lower activation energy compared to crosslinked membrane, indicating that the permeants require less energy during the process because of molecular sieving action attributed to the presence of sodalite and super cages in the framework of NaY zeolite. The Henry's mode of sorption dominates the process, giving an endothermic contribution.

Guided bone regeneration with tripolyphosphate cross-linked asymmetric chitosan membrane

ObjectivesThe objective of this study was to prepare a novel asymmetric chitosan guided bone regeneration (GBR) membrane, which is composed of a dense layer isolating the bone defect from the invasion of surrounding connective fibrous tissue and a loose layer which can improve cell adhesion and stabilize blood clots, thus guided bone regeneration. MethodsThe chitosan membrane was fabricated through liquid nitrogen quencher combined with lyophilization and cross-linked by sodium tripolyphosphate (TPP). The physical properties of asymmetric chitosan membrane were measured by scanning electron microscope (SEM), Fourier-transform infrared (FTIR), x-ray diffraction (XRD) and tensile test machine. MTT assay and Live/Dead cell staining for MC3T3-E1 osteoblasts cultured on the membrane were used to characterize the biocompatibility of the membrane. In animal experiments, full-thickness and critical sized skull defects were made to evaluate the effect of the membrane on bone regeneration. ResultsThe results of this study indicate that the asymmetric chitosan membrane can be built and cross-linked by TPP to enhance the tensile strength of the membrane. In vitro experiment showed that no significant numbers of dead cells were detected on the chitosan membrane, indicating that the membrane had good biocompatibility. In animal experiments, the chitosan membrane had faster new bone formation, showing the capability to enhance bone regeneration. ConclusionsThe chitosan membrane prepared in this study has an asymmetric structure; its tensile strength, biodegradation and biocompatibility fulfil the requirements of guided bone regeneration. Therefore, the asymmetric chitosan membrane is a promising GBR membrane for bone regeneration. Clinical significanceGuided bone regeneration (GBR) is an effective method for healing bone defects caused by periodontitis and implantitis, in which GBR membrane is a key biomaterial.

Cu(II) Ion Adsorption onto Hydroxymethylated Lignin-Chitosan Crosslinked Membrane

A crosslinked chitosan membrane (I) and a hydroxymethylated lignin-chitosan crosslinked membrane (II) were prepared using glutaraldehyde as the crosslinking agent. Fourier transform infrared spectroscopy (FTIR) was used to identify the chemical structures of the crosslinked membranes and the presence of an absorption peak at 1515 cm-1 indicated the presence of lignin. Scanning electron microscope (SEM) images revealed that membrane (I) possessed a smooth surface, while membrane (II) exhibited a homogeneous embossed surface without any agglomeration. The Cu(II) ion adsorption properties of both membranes were analyzed. The results indicated that the static adsorption capacities of membranes (I) and (II) were 195 g Cu(II)/cm2 and 275 g Cu(II)/cm2, respectively, and their dynamic chelation capacities were 2.89 g Cu(II)/cm2 and 4.59 g Cu(II)/cm2, respectively. Membrane (I) was suitable only for use in aqueous solutions with pH values of 3.5 to 9.0, while membrane (II) maintained its shape even in concentrated hydrochloric acid or 1 M NaOH solution. The Cu(II) ion absorption properties and resistance to acid and alkali of membrane (II) were superior to those of membrane (I), indicating that hydroxymethylation of the lignin-chitosan crosslinked membrane is worthy of further investigation.

A Highly Efficient and Stable Palladium Catalyst Entrapped within the Cross-Linked Chitosan Membrane for Heck Reactions

In this study, chitosan directly cross-linked by PdII cation membranes (Pd-cr-CSM) with good mechanical strength and thermal stabilities have been prepared. Although the prepared Pd-cr-CSM has neither open porous structure nor high specific surface areas, it has similar good catalytic activity and much higher stability as compared with typical prepared chitosan-stabilized palladium heterogeneous catalysts for Heck reactions. It is highly active for the Heck reactions of aryl iodides and bromides with a strong electron-withdrawing group at a palladium catalyst loading of 0.15 mol %. It can be recycled 12 times in dimethyl sulfoxide (DMSO) solution or 7 times in aqueous solution. The high activity and extreme stability of the Pd-cr-CSM catalyst are mainly attributed to the well-entrapped palladium nanoparticles inside the chitosan matrix, which might catalyze the coupling reactions in the free volume holes (open spaces) of the swollen cross-linked chitosan gel networks.

Transferable crosslinked chitosan membranes for human melanocyte culture

Development of transferable biocompatible membranes, which can be used for melanocyte culture and transplantation, is considered a feasible approach to increase the success rate for vitiliginous treatment. In this study, a crosslinked chitosan membrane (CCM) was produced via physical crosslinking of chitosan with sodium sulfate. The physical and mechanical properties as well as growth and phenotype expression of melanocytes on the CCM were investigated. The CCM supported growth and proliferation of melanocytes with the existence of melanin granules in the cytoplasm. The melanocytes remained active after transplantation. The CCM absorbed water approximately doubled from its original weight and permitted ∼2400 g/m² per day of water vapor transmission, suggesting that the CCM can function as an efficient wound dressing. Dynamic mechanical and tensile measurement results showed that the CCM possessed favorable wet strength for cell culture, separation, transfer, and transplantation application. This transferable CCM has the potential to be applied for vitiligo treatment.

A high performance direct borohydride fuel cell employing cross-linked chitosan membrane

A cross-linked chitosan (CCS) membrane has been prepared by a solution casting method using sulfuric acid as cross-linking agent. The CCS membrane was used as the polymer electrolyte and separator in a direct borohydride fuel cell (DBFC). Ionic conductivity and borohydride crossover rate have been measured for the CCS membrane. The DBFC used in this study employed nickel-based composite as anode catalyst and Nafion® as anode binder. The power performance of the CCS membrane-based DBFC was compared with a similar DBFC employing Nafion® 212 (N212) membrane as electrolyte /separator. The CCS membrane-based DBFC exhibited better power performance as compared to N212 membrane-based DBFC. Encouraged by this result, chitosan chemical hydrogel (CCH) was prepared and used as binder for anode catalysts. A DBFC comprising CCS membrane and CCH as anode binder was studied and found to exhibit even better power performance at all temperatures in this study. A maximum peak power density of 450mWcm−2 was observed at 60̊C for DBFC employing CCS membrane and CCH binder-based anode. The chitosan-based DBFC was operated continuously for 100h and its performance stability was recorded.

Monodisperse core-shell chitosan microcapsules for pH-responsive burst release of hydrophobic drugs

Monodisperse core-shell microcapsules based on crosslinked chitosan membrane with acid-triggered burst release properties are successfully developed. The microcapsules are fabricated from double emulsion precursors that are prepared with a microfluidic approach. In neutral medium (pH 7.1), the microcapsules maintain a good spherical shape and structural integrity; while, in acidic medium (pH 1.5 ∼ 4.7), the microcapsules decompose rapidly and release the encapsulated contents completely in short periods varying from 39 s to 22 min. The acid-triggered burst release pattern from the proposed chitosan microcapsules may make them capable for stomach-specific drug delivery systems with quick and complete release characteristics in a controllable pH-responsive manner.

Improving the pervaporation performance of the glutaraldehyde crosslinked chitosan membrane by simultaneously changing its surface and bulk structure

Preparation of CS-based membranes by pre-drying a chitosan/glutaraldehyde (CS/GA) solution for a certain time, followed by an acetone-immersion treatment, allowed the bulk characteristics of the resulting acetone-immersed CS (CSA) membranes to be changed. A decrease in pre-drying time resulted in that the degree of crystallinity was significantly decreased and the mobility of the polymer chains was less restricted. Pervaporation results indicated that the flux increased significantly and the water selectivity decreased with a decrease in pre-drying time. With an increase in relaxation time or degree of crystallinity, the activation energy of the pervaporation process ( E p) experienced an approximately linear increase. The permselectivity of the CSA membrane prepared with a shorter pre-drying time was further improved by introducing carboxyl groups onto its surface. For separating 90% ethanol/water mixtures at 60 °C, the surface-modified CSA membrane showed a separation factor of 500 and a flux of 400 g/m 2 h, which are about 5 and 1.6 times greater, respectively, compared to the corresponding crosslinked CS membrane without bulk and surface modification. This indicates that the combination of bulk modification and surface functionalization is an effective approach for simultaneously improving the flux and selectivity of polymeric membranes.

Cu(II)-Cross-linked Chitosan Membrane (CCCM): Preparation, Characterization and Urea Removal Study Using the Diffusion-Cell Model (DCM)

This work focuses on the investigation of antibacterial and biocompatible properties of a porous Cu(II)-cross-linked chitosan membrane (CCCM). The membrane shows fair biocidal action against the model bacterium Escherichia coli. The total protein and HSA adsorbed was found to be 263 and 75 μg/cm2. Finally, the 'diffusion cell model' was used to study adsorptive removal of urea from aqueous solutions. The results indicated that nearly 84.4% urea was removed by the membrane. Therefore, the Cu(II)-cross-linked membrane has potential to be used for as an alternative for hemodialysis membrane.

Genipin Cross-Linked Polymeric Alginate-Chitosan Microcapsules for Oral Delivery: In-Vitro Analysis

We have previously reported the preparation of the genipin cross-linked alginate-chitosan (GCAC) microcapsules composed of an alginate core with a genipin cross-linked chitosan membrane. This paper is the further investigation on their structural and physical characteristics. Results showed that the GCAC microcapsules had a smooth and dense surface and a networked interior. Cross-linking by genipin substantially reduced swelling and physical disintegration of microcapsules induced by nongelling ions and calcium sequestrants. Strong resistance to mechanical shear forces and enzymatic degradation was observed. Furthermore, the GCAC membranes were permeable to bovine serum albumin and maintained a molecular weight cutoff at 70 KD, analogous to the widely studied alginate-chitosan, and alginate-poly-L-lysine-alginate microcapsules. The release features and the tolerance of the GCAC microcapsules in the stimulated gastrointestinal environment were also investigated. This GCAC microcapsule formulation offers significant potential as a delivery vehicle for many biomedical applications.

Maleic anhydride surface-modification of crosslinked chitosan membrane and its pervaporation performance

Surface modification is a promising method to improve polymeric membrane's pervaporation performance. In this paper, the surface carboxylation of glutaraldehyde crosslinked chitosan (CS-GA) membrane was successfully achieved by the reaction of amine groups on the CS-GA membrane surface with anhydride groups of maleic anhydride (MA) in acetone solution. The resulting membrane was characterized by attenuated total reflectance-Fourier transform infrared spectra (ATR-FTIR), X-ray photoelectron spectroscopy (XPS) and contact angle measurement. The pervaporation performance of MA surface-modified CS-GA membrane (CS-GA-MA) for the separation of various organic/water mixtures was investigated. The results showed that both the flux and the separation factor were enhanced as CS-GA membrane was treated by MA. For the separation of 90 wt% ethanol/water mixture at 60 °C, the separation factor and the flux of the CS-GA-MA membrane were 634 and 300 g/m 2 h, respectively. However, the separation factor and the flux of the un-modified CS-GA membrane was 105 and 250 g/m 2 h. Meanwhile, the flux increased greatly and the water concentration in the permeate decreased slightly (by about 0.7%) as the operating temperature increased from 30 to 60 °C. Similar results were observed when the modified membrane was employed to separate various aqueous organic solutions. These data indicated that the surface carboxylation was a very effective method to improve pervaporation performance of CS-GA membrane for the separation of aqueous organic mixtures.

Preparation and characterization of novel polymeric microcapsules for live cell encapsulation and therapy

This article describes the preparation and in vitro characterization of novel genipin cross-linked alginate-chitosan (GCAC) microcapsules that have potential for live cell therapy applications. This microcapsule system, consisting of an alginate core with a covalently cross-linked chitosan membrane, was formed via ionotropic gelation between calcium ions and alginate, followed by chitosan coating by polyelectrolyte complexation and covalent cross-linking of chitosan by naturally derived genipin. Results showed that, using this design concept and the three-step procedure, spherical GCAC microcapsules with improved membrane strength, suppressed capsular swelling, and suitable permeability can be prepared. The suitability of this novel membrane formulation for live cell encapsulation was evaluated, using bacterial Lactobacillus plantarum 80 (pCBH1) (LP80) and mammalian HepG2 as model cells. Results showed that capsular integrity and bacterial cell viability were sustained 6 mo postencapsulation, suggesting the feasibility of using this microcapsule formulation for live bacterial cell encapsulation. The metabolic activity of the encapsulated HepG2 was also investigated. Results suggested the potential capacity of this GCAC microcapsule in cell therapy and the control of cell signaling; however, further research is required.

Genipin Cross-Linked Alginate-Chitosan Microcapsules: Membrane Characterization and Optimization of Cross-Linking Reaction

The genipin cross-linked alginate-chitosan (GCAC) microcapsule, composed of an alginate core and a genipin cross-linked chitosan membrane, was recently proposed for live cell encapsulation and other delivery applications. This article for the first time describes the details of the microcapsule membrane characterization using a noninvasive and in situ method without any physical or chemical modifications on the samples. Results showed that the cross-linking reaction generated the fluorescent chitosan-genipin conjugates. The cross-linked chitosan membrane was clearly visualized by confocal laser scanning microscopy (CLSM). A straightforward assessment on the membrane thickness and relative intensity was successfully achieved. CLSM studies showed that the shell-like cross-linked chitosan membranes of approximately 37 microm in thickness were formed surrounding the microcapsule. The reaction variables, including cross-linking temperature and time significantly affected the fluorescence intensity of the membranes. Elevating the cross-linking temperature from 4 to 37 degrees C drastically intensified the membrane fluorescence, suggesting the attainment of a high degree of cross-linking on the chitosan membrane. Extended cross-linking time altered the cross-linked membranes in modulation. Although genipin concentration and cross-linking time had little effects on the membrane thickness, cross-linking at higher temperatures tended to form relatively thinner membranes.

FABRICATION AND EVALUATION OF CHITOSAN MEMBRANES FOR GUIDED TISSUE REGENERATION

Chitosan membranes were prepared by a thermal induced phase separation method, following treatment with nontoxic NaOH gelating and Na5P3O10, Na5SO3 crosslinking agents. Effects of these reaction agents on chitosan membranes were evaluated to survey the feasibility of using these membranes in guided tissue regeneration (GTR) application. The preliminary results showed chitosan membranes crosslinked with Na5P3O10 and Na2SO3 had gel content of 53.5% and 52.2%r, respectively. Contrarily, the chitosan matrix gelated with NaOH dissolved completely during gel content measurement. Chitosan membrane treated with Na5P3O10 had lowest elastic modulus of 12.9 Mpa as compared with other membranes treated with Na2SO3 (17.9Mpa) and NaOH(23.6Mpa). From SEM observations, NaOH gelated chitosan membrane had the smoothest surface morphology than others. However, Na5P3O10 crosslinked chitosan membrane had better cell adhesion and proliferation results in cell culture test. All three chitosan membranes degraded by about 23%∼28% of initial weight after a 90-day in vitro shaking test.

Chemiluminescent immunosensor for CA19-9 based on antigen immobilization on a cross-linked chitosan membrane

A novel chemiluminescent immunosensor for carbohydrate antigen 19-9 (CA19-9) based on the immobilization of CA19-9 on the cross-linked chitosan membrane was developed. The different membranes were characterized by atomic force microscopy (AFM) and infrared spectrum, respectively. Based on a noncompetitive immunoassay format, this proposed chemiluminescent immunosensor enabled a low-cost, flexible and rapid determination for CA19-9 in combination with flow injection analysis (FIA). After an off-line incubation of the analyte CA19-9 with horseradish peroxidase (HRP)-labeled anti-CA19-9, the mixture was injected into the immunosensor, which led to the trapping of free HRP-labeled anti-CA19-9 by the immobilized antigen in the immunosensor. The trapped HRP-labeled antibody was detected by chemiluminescence due to its catalytic activity following the reaction of luminol and H 2O 2. Under optimal conditions, the decreased chemiluminescent signal of the immunosensor was proportional to the CA19-9 concentration in the range of 2.0–25 U/ml with a detection limit of 1.0 U/ml. The immunosensor showed an acceptable accuracy and good reproducibility. The results of 20 human serum samples detected by this method were in acceptable agreement with those obtained by immunoradiometric assay. The proposed immunosensor provided a new promising tool for practical clinical detection of the serum CA19-9 level.