Preparation and characterization of porous scaffold composite films by blending chitosan and gelatin solutions for skin tissue engineering

Biodegradable polymers have significant potential in biotechnology and bioengineering. However, for some applications, they are limited by their inferior mechanical properties and unsatisfactory compatibility with cells and tissues. In the present investigation blends of chitosan and gelatin with various compositions were produced as candidate materials for biomedical applications. Fourier transform infrared spectral analysis showed good compatibility between these two biodegradable polymers. The composite films showed improved tensile properties, highly porous structure, antimicrobial activities, low water dissolution, low water uptake and high buffer uptake compared to pure chitosan or gelatin films. These enhanced properties could be explained by the introduction of free ? OH, ? NH₂ and ? NHOCOCH₃ groups of the amorphous chitosan in the blends and a network structure through electrostatic interactions between the ammonium ions (? NH³⁺) of the chitosan and the carboxylate ions (? COO^?) of the gelatin. Scanning electron microscopy images of the blend composite films showed homogeneous and smooth surfaces which indicate good miscibility between gelatin and chitosan. The leafy morphologies of the scaffolds indicate a large and homogeneous porous structure, which would cause increased ion diffusion into the gel that could lead to an increase in stability in aqueous solution, buffer and temperature compared to the gelatin/chitosan system. In vivo testing was done in a Wistar rat (Rattus norvegicus) model and the healing efficiencies of the scaffolds containing various compositions of chitosan were measured. The healing efficiencies in Wistar rat of composites with gelatin to chitosan ratios of 10:3 and 10:4 were compared with that of a commercially available scaffold (Eco‐plast). It was observed that, after 5 days of application, the scaffold with a gelatin to chitosan ratio of 10:3 showed 100% healing in the Wistar rat; however, the commercial Eco‐plast showed only a little above 40% healing of the dissected rat wound. Copyright © 2012 Society of Chemical Industry     

Preparation and characterization of a novel thermosensitive hydrogel based on chitosan and gelatin blends

In this study, a novel injectable in situ gelling thermosensitive hydrogel system based on chitosan and gelatin blends was designed and investigated. The addition of gelatin provides the correct buffering and other physicochemical conditions including control of hydrophobic interactions and hydrogen bonding, which are necessary to retain chitosan in solution at neutral pH near 4°C and furthermore to allow gel formation upon heating to body temperature. The chitosan/gelatin hydrogels were studied by FTIR, swelling, and rheological analysis. The rheological analysis evidenced the endothermic gelation of chitosan/gelatin solutions, which indicated their gelation temperatures and reflected the effect of gelatin concentration on the thermosensitive properties of gels. The morphology of this system was examined with laser scanning confocal microscopy and scanning electron microscopy. The images indicated that the gels were quite heterogeneous and porous. The investigation of these gels as vehicles for delivering bovine serum albumin as a model drug of protein showed that the system could sustain the release of the protein drug. These results show that chitosan/gelatin solutions can form gels rapidly at body temperature and have promising perspective for their use in local and sustained delivery of protein drug. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Preparation and characterization of novel chitosan/zeolite scaffolds for bone tissue engineering applications

In this study, chitosan-based novel scaffolds containing zeolite A were fabricated by freeze-drying technique. The nanocomposite scaffolds were prepared from chitosan and zeolite A nanocrystals with different amounts (0.5, 1.0, and 2.0%) in aqueous media. The zeolite A nanocrystals and nanocomposite scaffolds were characterized by using FTIR, X-ray powder diffraction, scanning electron microscope, and thermogravimetric analysis. The scaffolds were seeded with bone marrow-derived human mesenchymal stem cell line (UE7T-13), and cell attachment, viability, and cytotoxicity assays were performed. In vitro cytotoxicity of scaffolds toward human mesenchymal stem cell line was evaluated through the evaluation of cell viability and cell attachment assays.     

Preparation and characterization of alginate/Hydroxypropyl chitosan blend fibers

Hydroxypropyl chitosan (HPCS) was synthesized from chitosan and propylene oxide under alkali conditions. It was characterized by IR spectroscopy and X-ray diffraction (XRD). We prepared alginate/HPCS blend fibers by spinning their solution through a viscose-type spinneret into a coagulating bath containing aqueous CaCl₂ and ethanol. The structure and properties of the blend fibers were studied with the aid of IR spectroscopy, scanning electron microscopy, and XRD. The results indicate a good miscibility between alginate and HPCS because of the strong interaction of the intermolecular hydrogen bonds. The mechanical properties and water-retention properties were also measured. The best values of the tensile strength and breaking elongation of the blend fibers were obtained when the HPCS content was 30 wt %. The water-retention values of the blend fibers increased as the amount of HPCS increased. Antibacterial fibers, obtained by the treatment of the fibers with an aqueous solution of silver nitrate, exhibited good antibacterial activity to Staphylococcus aureus. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Fabrication and characterization of chitosan/kefiran electrospun nanofibers for tissue engineering applications

Chitosan (CS)-based nanofibrous scaffolds are very promising in tissue engineering applications. However, electrospinning of CS is not possible unless using toxic solvents such as trifluoroacetic acid or by blending with other polymers. In the present study, we investigated CS-based nanofibers' fabrication by blending it with kefiran as a natural polysaccharide. A series of solutions with various CS to kefiran ratios were prepared and underwent electrospinning. The effects of main process parameters, including applied voltage and needle tip-to-collector distance on nanofibers' diameter and morphology, were also studied. Nanofibers containing 80% CS and 20% Kefiran with an average diameter of 81 ± 17 nm were successfully electrospun. Thermogravimetric analysis indicated the presence of both polymers in blend nanofibers. The diameter of CS/kefiran nanofibers increased with enhanced applied voltage, while needle tip-to-collector distance did not significantly affect the mean diameters. Appropriate viability of l929 cells on the obtained scaffolds was demonstrated utilizing Alamar blue assay. Also, cell attachment onto the fiber surface was confirmed by scanning electron microscopy. Results indicated that CS/kefiran nanofibrous scaffolds would be promising for tissue engineering applications.     

A study on the fabrication of porous chitosan/gelatin network scaffold for tissue engineering

A novel porous chitosan/gelatin scaffold for tissue engineering was prepared via polyelectrolyte complex formation, freeze drying and post‐crosslinking with glutaraldehyde. The porosity and mean pore diameters could be controlled within 30∼100 µm by varying the original water content and the freezing conditions. Dipping the scaffolds in poly(lactic acid) provided good mechanical properties making it a promising candidate towards tissue engineering. © 2000 Society of Chemical Industry     

Synthesis,characterization, and enzymatic degradation of chitosan/PEG hydrogel films

Poly(ethyleneglycol) (PEG)/tartaric acid (TA)‐crosslinked chitosan hydrogel (CPT) films were prepared, and the formation of the PEG/TA‐crosslinked structure was confirmed by Fourier transformed infrared (FTIR), nuclear magnetic resonance (NMR), and scanning electron microscope (SEM) measurements. The thermal properties of the crosslinked films were also determined with thermogravimetric analysis (TGA) and differential scanning calorimeter (DSC) analysis. The swelling properties of the films were investigated at different temperature and pH values. It was found that the swelling ratio increased with the decrease of pH value of the surrounding buffer solutions, amount of PEG, and with the increase of temperature. Swelling behavior of the PEG/TA‐crosslinked chitosan hydrogel films depended on pH and reversible with the temperature. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Preparation and characterization of chitosan–zeolite composites

Double crosslinked chitosan–zeolite (CZ-2) and noncrosslinked chitosan–zeolite (CZ-0) composites were prepared and characterized by using Fourier transform infrared (FTIR) spectrometer, surface area analyzer, scanning electron microscope coupled with energy dispersive X-ray (SEM-EDX) spectrometer, thermogravimetric analyzer (TGA), X-ray diffraction analyzer (XRD) and carbon, hydrogen, nitrogen (CHN) analyzer. After crosslinking, CZ-2 showed a reduction in surface area and CHN content in comparison to chitosan, zeolite, and CZ-0. Crosslinking resulted in improved stability of CZ-2 in distilled water, acetic acid and NaOH as CZ-2 recorded the lowest percentage of swelling. XRD diffractograms confirmed the formation of composites as there was a marked difference in the peak intensity at 2θ = 19.8°. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Preparation of biomimetic three-dimensional gelatin/montmorillonite–chitosan scaffold for tissue engineering

A novel gelatin/montmorillonite–chitosan (Gel/MMT–CS) nanocomposite scaffold was prepared via the intercalation process and the freeze-drying technique, using the ice particulates as the porogen materials. Properties including pore structure, water adsorption content, in vitro degradation and tensile strength were investigated. It was demonstrated that the introduced intercalation structure endowed the Gel/MMT–CS scaffold with good mechanical properties and a controllable degradation rate. Scanning of the electron microscope images revealed that the scaffold obtained was highly porous and suitable for the implanted cells to adhere and grow. The mitochondrial activity assay provided good evidences of cells viability on the Gel/MMT–CS membranes, giving an indication of possible application as a matrix for tissue engineering.     

Preparation and characterization of gelatin/hydroxyapatite nanocomposite for bone tissue engineering

Homogeneous gelatin/hydroxyapatite (GEL/HA) nano‐composites were synthesized by a novel in situ precipitation method, and its corresponding characterizations, including composition, morphology, pore structure, thermal stability, mechanical strength, and biocompatibility, were carried out. High‐magnified scanning electron microscope (SEM) images indicated that nano‐HA with particle size ranging from 20 to 50 nm were uniformly distributed in GEL matrix and tightly integrated with organic phase. Wide angle X‐ray diffraction (XRD) analysis and transmission electron microscope (TEM) images showed that, during the process of mineralization, there existed preferred oriented growth of HA crystals along (002) and (211) crystal planes. Thermogravimetric analysis (TGA) and differential thermal analysis (DTA) indicated that, the thermal stability of GEL molecules enhanced by hybridizing with HA nanocrystals. Interconnected porous GEL/HA nanocomposites with pore size ranging between 50 and 350 μm were prepared by a freeze‐drying method. This pore size was adequate for bone tissue engineering (BTE) applications. In addition, in vitro MG63 osteoblast‐like cell culture illuminated that GEL/HA nanocomposites had excellent cytocompatibility and could promote proliferation of cells. These results suggested that GEL/HA nanocomposite might be an ideal bone substitute. POLYM. COMPOS., 38:1579–1590, 2017. © 2015 Society of Plastics Engineers     

聚己内酯/壳聚糖核壳结构纤维引导组织再生膜的制备及表征

高性能的引导组织再生膜是牙周引导组织再生术成功的关键,静电纺丝法因可仿生制备类细胞外基质结构,在引导组织再生膜研制方面显示出巨大潜力。本研究通过同轴静电纺丝法,以聚己内酯（PCL）为核层,壳聚糖（CS）为壳层,制备核壳结构的纳米纤维,并用香草醛对制备的纤维膜进行交联。利用扫描电子显微镜（SEM）、透射电子显微镜（TEM）、X 射线衍射（XRD）、傅里叶变换红外光谱（FTIR）、力学测试及细胞培养等手段对制备的纤维膜进行形貌、内部结构、化学组成、力学性能和细胞相容性表征。结构分析表明本研究成功制备了核壳结构的PCL-CS纤维膜。力学测试和亲疏水性测试结果表明交联后的纤维膜具有较好的耐水性和力学性能,断裂强度高出文献报道值近两倍;体外细胞培养结果显示MG-63细胞能在交联后的纤维膜上黏附和持续增殖,表明纤维膜具有较好的细胞相容性,在引导组织再生领域有较好的应用前景。     

壳聚糖/明胶抗菌微胶囊的制备及其应用

为了制备用于棉织物天然抗菌整理剂,以绿苋、龙葵和黄柏的复配提取物为芯材,壳聚糖-明胶为壁材,采用复凝聚法制备抗菌微胶囊。研究了乳化剂含量、剪切速度、pH对微胶囊的外观形态及尺寸的影响;借助扫描电子显微镜、傅里叶红外光谱仪等对样品进行表征;将抗菌微胶囊用于棉织物的整理并测试其抗菌性能。结果表明：初乳中乳化剂质量分数为5%、剪切速度为8000r/min、pH为5.7为最佳制备条件,制得的微胶囊尺寸分布在1480～3580nm且热稳定性良好;当微胶囊质量浓度为25g/L,黏合剂质量分数为5%,热烘温度为40℃,整理试样对金黄色葡萄球菌和大肠杆菌的抑菌率分别为89.30%和81.43%,且抑菌效果持久。     

Preparation and characterization of novel sodium alginate/chitosan two ply composite membranes

Sodium alginate/chitosan (SA/CS) two ply composite membranes were prepared by casting and solvent evaporation technique. NaHCO₃ was used as a porogen additive to form pores in the interior of the composite membranes and glycerol was introduced as a plasticizer. The water uptake capacity, mechanical strength, oxygen permeation property, and in vitro cytotoxicity were evaluated to test the feasibility to utilize the composite membranes for wound dressing. The average pore size, water uptake capacity, and oxygen permeation property of the composite membranes could be adjusted by the ratio of NaHCO₃ in the SA solution. The SA/CS two ply composite membranes showed high water uptake capacity, suitable mechanical strength, excellent oxygen permeability, and good biocompatible. It indicates that the SA/CS two ply composite membranes are suitable for wound dressing application. It provides a simple but promising platform to fabricate wound dressing using natural polymers. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Preparation and characterization of artificial skin using chitosan and gelatin composites for potential biomedical application

A bioadhesive wound-dressing material based on the combination of gelatin and chitosan with a proper ratio was developed and successfully applied in biomedical fields. The composite films were prepared with increase in chitosan concentration in a fixed amount of gelatin and were evaluated for mechanical stability (e.g., tensile strength, elongation-at-break), water and buffer uptake capacity, water and buffer aging, molecular structure, morphology, thermal stability, and for biological properties (e.g., antimicrobial activity, cytotoxicity, in vivo wound-healing performance). It is noteworthy that the 10:3 (gelatin:chitosan) composite films showed the best physico-mechanical, thermal, and antimicrobial properties among the other ratios blend films. The improved mechanical and thermal stability of the 10:3 composite film suggested its promising use as carrier for controlled release drug. The composite film was evaluated using a rat model for in vivo tests to ascertain the applicability of the proper ratio of the chitosan and gelatin in the film for best wound-healing activity. Wound sites dresses with gelatin/chitosan composite films showed excellent rapid healing of the wound surface than those dressed with eco-plaster and gauze. Within a day after dressing with 10:3 composite film, the healing efficiency was found to be 80?%.     

Preparation and characterization of novel chitosan/nanodiopside/nanohydroxyapatite composite scaffolds for tissue engineering applications

Chitosan/nanodiopside/nanohydroxyapatite (CS/nDP/nHAp) composite scaffolds were prepared from the mixture of chitosan, nDP, and nHAp in different inorganic/organic weight ratios by using the freeze-drying method. The prepared nHAp and composite scaffolds were investigated using BET, TG, FT-IR, SEM, EDS, and XRD techniques. The composite scaffolds had 50–85% porosities with interlinked porous networks. Moreover, investigation of the cell proliferation, adhesion, and viability using MTT test, and mouse preosteoblast cell proved the cytocompatibile nature of the composite scaffolds with improved cell attachment and proliferation. All these results essentially illustrated that this composite could be a potential for bone tissue engineering applications.     

季铵化壳聚糖-聚苯乙烯共混膜的制备及表征

以十六烷基三甲基溴化铵(CTAB)为表面活性剂,过硫酸钾为引发剂制备了聚苯乙烯微乳液,用共混法制备了3种不同质量比的季铵化壳聚糖和聚苯乙烯微乳液的共混膜.研究了该膜的温度和pH的敏感性及力学强度.结果表明,共混膜的拉伸强度与纯壳聚糖膜相比有较大提高,而且该膜仍然具有一定的温度敏感性和pH敏感性,有较好的应用价值.     

Electrospun polycaprolactone/gelatin/bioactive glass nanoscaffold for bone tissue engineering

Polycaprolactone scaffolds, polycaprolactone/gelatin, and polycaprolactone/gelatin/bioactive glass scaffolds were prepared with ratios of 50/50, 25/75, and 75/25 for polymers and 5?wt% for the bioactive glass via electrospinning and then were characterized using. The results indicated that by adding gelatin and bioactive glass to polycaprolactone scaffold, the diameter of fiber decreased from 557 to 167?nm. The results showed growth of apatite layer on the scaffolds after immersion in simulated body fluid for 28?days. The results of mechanical test revealed that by adding bioactive glass to scaffolds, the ultimate tensile strength and Young's modulus increase about two folds.     

Preparation and characterization of cellulose fiber/chitosan composites

Cellulose fiber/chitosan biodegradable rod (CF/CS rod) with layer‐by‐layer structure, good mechanical properties, and excellent X‐ray developing capability was successfully constructed via in‐situ precipitated method. As the ratio of CF to CS was 0.2/20 (wt/wt), the bending strength and bending modulus arrived at 124.1 MPa and 4.3 GPa, respectively, were significantly improved compared with pure CS rod. TGA indicated that the thermal stability of CS rod could be enhanced by mixing with CF, but fiber and matrix are partially compatible. SEM made clear that fibers were randomly dispersed in the CS matrix to connect layers of CS rod that can endure stress. FTIR spectra illuminated that small amount of Schiff base was formed due to the chemical reaction between fibers and CS matrix, which could enhance the mechanical combining stress of the interface. Thus, CF/CS rod has great potential to be used as internal fixation of bone fracture. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers     

聚苯胺/壳聚糖超级电容器电极复合材料的制备及表征

采用冷冻干燥后管式炉碳化制备壳聚糖电极材料,经KOH活化法活化后通过氧化还原聚合法制备聚苯胺(PANI)/壳聚糖电极材料,运用循环伏安、交流阻抗、充放电等测试聚苯胺/壳聚糖电极的电化学性能。结果表明,聚苯胺/壳聚糖电极材料表现出良好的电容性能和稳定的电化学性能,比电容129.6 F/g,循环充放电500次,比电容保持率90.8%。     

聚苯胺/壳聚糖超级电容器电极复合材料的制备及表征

采用冷冻干燥后管式炉碳化制备壳聚糖电极材料,经KOH活化法活化后通过氧化还原聚合法制备聚苯胺(PANI)/壳聚糖电极材料,运用循环伏安、交流阻抗、充放电等测试聚苯胺/壳聚糖电极的电化学性能。结果表明,聚苯胺/壳聚糖电极材料表现出良好的电容性能和稳定的电化学性能,比电容129.6 F/g,循环充放电500次,比电容保持率90.8%。