Chitosan Gelatin Research Articles

Effect of chitosan-gelatin coating fortified with papaya leaves and thyme extract on quality and shelf life of chicken breast fillet and Kareish cheese during chilled storage

A novel antimicrobial chitosan-gelatin based edible coating fortified with papaya leaves and thyme extract was prepared for improving the quality and shelf-life of chicken breast fillet and Kareish cheese during chilled storage at 4 ± 1 °C. The samples were dipped for 10 min in distilled water (control), chitosan-gelatin (CG), chitosan-gelatin +2% papaya leaves extract (CG + P) and chitosan-gelatin +2% thyme extract (CG + Th). The coated and uncoated samples were examined periodically for sensory attributes, pH, TBARs, total aerobic mesophilic (TAM), total Enterobacteriaceae (TE), and total yeasts and molds counts (TYM). Sensory evaluation revealed that chicken breast fillet and Kareish cheese samples coated with CG + P were the best in terms of tenderness, juiciness, body & texture and flavor. CG + Th exhibited the highest antimicrobial and antioxidant effect, followed by CG + P. The results of microbiological, physicochemical and sensory analysis of this study demonstrated that the application of CG + P or CG + Th could be a promising method for increasing the shelf life and improving the quality of chicken breast fillet and Kareish cheese.

Nanoparticle-modified coatings by electrophoretic deposition for corrosion protection of magnesium

ABSTRACT Magnesium (Mg) and its biocompatible alloys are used as biodegradable materials for temporary implant applications. However, the fast electrochemical reactions in the physiological environment can lead to premature implant failure and damage the surrounding tissues. Here, we report on nanoparticle-modified biopolymer composite coatings processed using alternating current electrophoretic deposition (AC-EPD) to control the corrosion process of Mg–Al alloys. Chitosan–gelatin coatings incorporating bioactive glass particles as reinforcement were supplemented with ZnO and CeO2 nanoparticles and the corrosion resistance was evaluated. CeO2 nanoparticle-modified coatings obtained using AC signals superimposed with a direct current field appeared compact and homogeneous. ZnO nanoparticle-modified coatings had a low surface coverage with significant defects. As a result, CeO2-supplemented coatings processed for as little as 4 min effectively reduced the corrosion current density (i corr) of Mg–Al in Ringer’s solution, whereas ZnO-supplemented coatings did not. CeO2 nanoparticle-modified biopolymer coatings hold potential for fine-tuning the degradation of Mg implants.

Effects of Additional Polyvinyl Alcohol (PVA) on the Physiochemical Properties of Chitosan-Glutaraldehyde-Gelatine Bioplastic

This study investigated the effects of additional PVA on the physicochemical properties of the chitosan-glutaraldehyde/gelatin bioplastic composite. The best results of the bioplastic film were obtained at a concentration of 3% PVA, with a tensile strength value of 3.3 MPa, flexibility reached 54%, a thickness value of 0.24 mm, percentage of inhibition against E. coli and S. aureus was 21.8% and 8.8% respectively. The FTIR spectrum results showed no change in the wavenumber of the chitosan and gelatin chitosan spectrum with OH, CO, and NH functional groups. The spectrum indicates that only physical interactions occurred. The bioplastics are similar in thermal stability and have slight differences in bioplastic morphological contours. The average thickness of the bioplastics is between 0.20–0.26 mm. Based on the Japanese Industrial Standard (JIS), all bioplastics meet the standard thickness, which is < 0.25 mm, excluding chitosan, which has a thickness of 0.26 mm. The addition of PVA into the bioplastics structure increased the hydrophobicity, pH resistance, and flexibility of bioplastics. Meanwhile, additional PVA decreased biodegradability, only degraded by 60% at eight weeks. Based on these data, not all bioplastics can meet the degradation time criteria set by the international bioplastic standard ASTM D-6002, that bioplastics must be 100% degraded within eight weeks. Bioplastics made from chitosan and chitosan-gelatin have been degraded by 90% for 48 weeks. Based on the antibacterial properties, the inclusion of PVA into the bioplastic structure enhances the antibacterial properties.

Mechanical improvement of chitosan–gelatin scaffolds reinforced by β-tricalcium phosphate bioceramic

This study aimed to fabricate and evaluate the properties of a chitosan–gelatin scaffold reinforced by beta-tricalcium phosphate (βTCP) powder derived from limestone as a composite scaffold for application in bone tissue engineering. Preparation of βTCP powder involved obtaining calcium hydroxide from limestone and mixing it with phosphate solution through wet precipitation and calcination. To fabricate the scaffold, chitosan was dissolved in acetic acid solution and mixed with gelatin-in-water solution. βTCP powder was then added to the mixture and crosslinked with glutaraldehyde. The slurry was dispensed into a mold and then freeze-dried. Dried chitosan–gelatin–βTCP scaffolds were then characterized. X-ray diffractometer (XRD) results showed that chitosan–gelatin scaffolds incorporated with βTCP displayed the phase composition corresponding to the βTCP reference. Fourier-transform infrared spectroscopy results showed increasing intensity of amide I and amide II at a lower βTCP amount because of the increasing amount of chitosan and gelatin where amide I and amide II groups were a characteristic of both materials. A porous structure was present in all scaffolds, as shown by scanning electron microscopy observation. The pore size as well as porosity (85.76% ± 0.77%) decreased with increased βTCP amount up to 70%, affecting the compressive strength of the scaffolds, with the highest value up to 3.27 ± 0.29 MPa. In conclusion, porous scaffolds suitable for bone tissue engineering applications were fabricated using a combination of limestone-derived βTCP powder, chitosan, and gelatin.

Graphene-Oxide Porous Biopolymer Hybrids Enhance In Vitro Osteogenic Differentiation and Promote Ectopic Osteogenesis In Vivo.

Over the years, natural-based scaffolds have presented impressive results for bone tissue engineering (BTE) application. Further, outstanding interactions have been observed during the interaction of graphene oxide (GO)-reinforced biomaterials with both specific cell cultures and injured bone during in vivo experimental conditions. This research hereby addresses the potential of fish gelatin/chitosan (GCs) hybrids reinforced with GO to support in vitro osteogenic differentiation and, further, to investigate its behavior when implanted ectopically. Standard GCs formulation was referenced against genipin (Gp) crosslinked blend and 0.5 wt.% additivated GO composite (GCsGp/GO 0.5 wt.%). Pre-osteoblasts were put in contact with these composites and induced to differentiate in vitro towards mature osteoblasts for 28 days. Specific bone makers were investigated by qPCR and immunolabeling. Next, CD1 mice models were used to assess de novo osteogenic potential by ectopic implantation in the subcutaneous dorsum pocket of the animals. After 4 weeks, alkaline phosphate (ALP) and calcium deposits together with collagen synthesis were investigated by biochemical analysis and histology, respectively. Further, ex vivo materials were studied after surgery regarding biomineralization and morphological changes by means of qualitative and quantitative methods. Furthermore, X-ray diffraction and Fourier-transform infrared spectroscopy underlined the newly fashioned material structuration by virtue of mineralized extracellular matrix. Specific bone markers determination stressed the osteogenic phenotype of the cells populating the material in vitro and successfully differentiated towards mature bone cells. In vivo results of specific histological staining assays highlighted collagen formation and calcium deposits, which were further validated by micro-CT. It was observed that the addition of 0.5 wt.% GO had an overall significant positive effect on both in vitro differentiation and in vivo bone cell recruitment in the subcutaneous region. These data support the GO bioactivity in osteogenesis mechanisms as being self-sufficient to elevate osteoblast differentiation and bone formation in ectopic sites while lacking the most common osteoinductive agents.

EFFECT OF Β-TRICALCIUM PHOSPHATE ELEMENTAL IMPURITIES ON THE ANTIBACTERIAL ACTIVITY OF CHITOSAN–GELATIN–ΒTCP COMPOSITE SCAFFOLD

This study aims to fabricate composite a scaffold using a mixture of chitosan-gelatin and limestone-extracted βTCP for better antibacterial properties. Limestone is abundantly available in nature and can provide calcium in the production of calcium phosphate (CaP) materials. However, the elemental impurities present in limestone-extracted βTCP may affect the properties of the CaP-fabricated scaffolds. βTCP powder could be used to fabricate bone scaffold using calcination and wet precipitation method. For example, the preparation of βTCP powder involved the transformation of calcium carbonate in limestone to calcium hydroxide, followed by a reaction with phosphoric acid and sintering treatment to form βTCP. In order to fabricate the scaffold, chitosan was first dissolved in acetic acid and then mixed with a gelatin-in-water solution, followed by adding βTCP powder (limestone-extracted βTCP and commercial βTCP). Then, the mixture was placed in a mold and freeze-dried. Our method improved the antibacterial activity of chitosan–gelatin–βTCP compared to the chitosan–gelatin scaffold. Limestone-extracted βTCP also exhibited higher inhibitory action against bacteria than commercial βTCP. This method's effectiveness evaluation was confirmed by the measurement of X-ray fluorescence analysis, which showed that βTCP scaffolds had more antibacterial elements than the chitosan–gelatin scaffold. These new research results contribute to enhanced antibacterial properties of the material due to elemental impurities in βTCP, especially the limestone-extracted βTCP. However, further evaluation on controlling βTCP impurities is essential for better outcomes in clinical applications.

Highly Adhesive Antibacterial Bioactive Composite Hydrogels With Controllable Flexibility and Swelling as Wound Dressing for Full-Thickness Skin Healing.

Polyzwitterionic hydrogels as skin wound dressings have been extensively studied owing to their superior antibacterial properties and skin adhesiveness, but their practical applications still suffer from a low adhesion strength and a high swelling ratio, which hinder the application of hydrogel for cutaneous healing. Here, we developed a novel biocompatible poly[2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium hydroxide (PolySBMA) composite hydrogel with high stretchability, low swelling, strong skin adhesiveness, and antibacterial effect for enhancing wound healing. Naturally rigid polymers including quaternized chitosan methacrylate (QCSMA) and gelatin methacrylate (GelMA) are used as bioactive cross-linkers to endow PolySBMA/QCSMA/GelMA (SQG) hydrogel with a low swelling ratio and high bioactivity. The optimized hydrogel has excellent mechanical flexibility, with the ultimate tensile strength, tensile strain, modulus, and toughness of up to 344.5 kPa, 364%, 14.7 kPa, and 33.4 kJ m−3, respectively. The adhesiveness of the hydrogel to the skin tissue is as high as 38.2 kPa, which is critical for stopping the bleeding from the wound. The synergistic contributions from the PolySBMA and QCSMA endow hydrogel with good antibacterial properties against both Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli. Moreover, the natural polymer cross-linked polyzwitterionic hydrogel shows good cell activity, hemocompatibility, and histocompatibility. The in vivo full-thickness skin defect model demonstrates that the SQG hydrogel efficiently improves the granulation tissue formation and collagen deposition. In summary, such superiorly skin-adhesive antibacterial biocompatible hydrogel with controllable flexibility and swelling holds great promise as wound dressings for acute wounds.

Prevention of Protein Oxidation in Chicken Meat during Chilled Storage Using Chitosan Gelatin Films with Green Tea Extracts

In present study, the usability of chitosan and gelatin (1:1) films incorporated with green tea extract (GTE) to improve the shelf life of the chicken meat stored in chilled condition was evaluated. The extract of green tea was evaluated for its phenolic content, antioxidant activity and ferric ion chealating ability. The ChGel films possessed antimicrobial activity and inactivated approximately 3 log cfu/ ml of K. pneumoniae, S. typhi var. Weltevreden, S. typhi var. Oslo, Y. enterocolitica, E. feacalis, B. cereus, E. coli and S. aureus in 3 hours. Incorporation of GTE influenced the optical and mechanical properties of the films. Chicken samples without films were observed to be microbiologically safe for not more than 6 days, while ChGel and ChGel-GTE films improved the microbial safety of chicken samples till day 13. ChGel-GTE films also prevented lipid peroxidation in samples as evident by TBARS value (day 10: control: 1.14; ChGel-GTE: 0.21 mg MDA eq/kg). Protein oxidation during chilled storage of chicken was also prevented by ChGel-GTE by inhibiting protein carbonylation, loss of free thiols groups in protein and lowering the number of disulphde bonds. This study supports use of ChGel films with GTE for enhancing the safety of stored chicken meat not only by maintaining the microbial quality of the samples but also preventing oxidative changes which can hamper the functional, nutritional and sensorial properties.

Enhancement of water absorption capacity and compressibility of hydrogel sponges prepared from gelatin/chitosan matrix with different polyols

The hydrogel sponges have prepared successfully from gelatin/chitosan (GEL/CTS) matrix with different polyols basing on scanning electron microscopy (SEM) and Fourier-transform infrared spectroscopy (FTIR) analysis. The results indicate that the compressibility and thermal properties (thermal gravimetric analysis, TGA) were improved significantly with adding the different polyols [poly(vinyl alcohol) – PVA, and poly(ethylene glycol)-poly(propylene glycol)- poly(ethylene glycol) – PEPEG] into GEL/CTS matrix. Specially, the as-prepared hydrogel sponges with superabsorbent behavior were also investigated with the attained water absorption capacity to 605 ​g ​g−1 and 585 ​g ​g−1 for GCV_1/1/0.3 and GCE_1/1/0.3 sponges, respectively, as well as the excellent water absorption capacity in a wide range of pH and salt concentration. Hence, these studies demonstrated that the hydrogel sponges are concerned as potential and promising candidates to apply especially in the fields of biomedicine and hygiene.

Formulation of pH-sensitive aminated chitosan–gelatin crosslinked hydrogel for oral drug delivery

The objective of this study is to develop efficient pH-sensitive hydrogel based on aminated chitosan (AmCs) and gelatin (Gel) biopolymers for oral drug delivery. Herein, AmCs was chemically crosslinked with gelatin (Gel) biopolymer with different ratios, while their structures, thermal profiles and morphological properties were investigated by FTIR, TGA and SEM characterization tools, respectively. Moreover, gel-content, crosslinking density and rheological analysis were also performed. The results clarified that the developed AmCs-Gel crosslinked hydrogel displayed variable pH-sensitive swelling profiles. By increasing AmCs ratio, the swelling ratio was boosted at pH 1.2 and declined at pH 7.4. Besides, by increasing gelatin ratio in the hydrogel matrix, the loading efficiency of Oseltamivir phosphate (as a model of drug) was augmented and reached maximum value of 79.0% by AmCs-Gel (2:3) crosslinked hydrogel. The in vitro drug release profiles were investigated for 6 h in simulated gastric fluid [SGF; pH 1.2] and simulated colon fluid [SCF; pH 7.4]. Variable release profiles were realized depending on variation of AmCs and Gel ratios in the crosslinked hydrogel matrix. Finally, the formulated smart crosslinked AmCs-Gel hydrogels demonstrated acceptable biodegradability with no cellular toxicity, suggesting their applicability as pH-sensitive oral drug carriers.

Effect of rosemary essential oil and ethanol extract on physicochemical and antibacterial properties of optimized gelatin–chitosan film using mixture design

Effect of rosemary essential oil and ethanol extract on physicochemical and antibacterial properties of optimized gelatin–chitosan film using mixture design

Copper crosslinked carboxymethyl chitosan–gelatin scaffolds: A potential antibacterial and cytocompatible material for biomedical applications

The study delineates the development and characterization of carboxymethyl chitosan–gelatin-copper oxide (CuO) crosslinked scaffolds for biomedical applications. Four scaffolds were developed using lyophilization technique using two stage crosslinking and evaluated using FT-IR, TGA to ascertain the crosslinking. Further, swelling index (SI), hydrolytic degradation, water vapour transmission rate (WVTR) as well as morphological characterization of scaffolds were carried out using SEM and optical profilometer. Additionally, modified disc diffusion method and MTT assay was carried out to check antibacterial action and cyto-compatibility. The results revealed that SI, hydrolytic degradation, and WVTR changes with the change in percentage of CuO. Further, effect of CuO concentration was evident from roughness variations of the developed scaffolds. Additionally SEM images shows presence of micro pores and the scaffolds exhibited good antibacterial action both against Gram positive and Gram negative bacteria. Lastly cytotoxicity assay exhibited good cell viability even at higher concentration of CuO nanoparticles. Thus, this work represents a facile approach to develop CuO crosslinked scaffolds of CMCh-gelatin that may potentially be explored further for biomedical applications.

Fabrication and evaluation of homogeneous alginate/polyacrylamide–chitosan–gelatin composite hydrogel scaffolds based on the interpenetrating networks for tissue engineering

AbstractInterpenetrating polymer network (IPN) is generally considered to be one of the most effective methods for imparting high‐strength mechanical properties to hydrogel materials. To broaden the application of alginate hydrogel in skeletal muscle or muscle tissue engineering, the interpenetrating network technology and layer‐by‐layer (LBL) electrostatic assembly were proposed to fabricate the homogeneous alginate/polyacrylamide–chitosan–gelatin (Alg/PAAM–CS–GT) composite hydrogel scaffolds, using the hydroxyapatite/d‐glucono‐δ‐lactone (HAP/GDL) complex as the gelling system. The effects of different components of alginate/polyacrylamide (Alg/PAAM) on the morphology, mechanical properties, swelling, degradability, and cytocompatibility of the hydrogel scaffolds were comparatively characterized. Experimental results showed that the as‐prepared Alg/PAAM–CS–GT composite hydrogel scaffolds exhibited sharp edges and regular 3D structures. Their pore structure could be regulated by changing the content of PAAM in Alg/PAAM–CS–GT composite hydrogel scaffolds. And the filling of PAAM reduced the pores and thickened the pore walls, which obviously enhanced the mechanical properties of Alg/PAAM–CS–GT composite hydrogel scaffolds. FT‐IR and thermogravimetric analysis showed that O‧‧‧N hydrogen bonding between COOH of SA and NH2 of PAAM could be helpful to improve the thermal stability of the composite hydrogel scaffolds. The swelling and biodegradation measurements indicated that the swelling and degradation of Alg/PAAM–CS–GT composite hydrogel scaffolds could be effectively regulated by changing the component content of the composite hydrogel. In addition, the in vitro cytocompatibility analysis showed that the Alg/PAAM–CS–GT composite hydrogel scaffolds could support the growth of MC3T3‐E1 cells and promote cell proliferation and differentiation. According to the in vitro cytocompatibility test results, the optimum PAAM content for the Alg/PAAM–CS–GT composite hydrogel scaffolds was 60%. Because of good morphology, well‐developed pores, excellent mechanical properties, and high biological activity of Alg/PAAM–CS–GT composite hydrogel scaffolds, they could be suitable for application in the tissue engineering field.

In-vitro and in-vivo hemostat evaluation of decellularized liver extra cellular matrix loaded chitosan/gelatin spongy scaffolds for liver injury

Individually, Chitosan (C) and Gelatin (G) are increasingly being used for the simulation and testing of surgical procedures. In the present study, at combination of chitosan/gelatin (CG) was optimized and later enriched by the loading decellularized liver extracellular matrix powder (dLECM) prepared from porcine liver, we hypothesized CG-dLECM combination would enhance wound healing and reduce postoperative complications after liver surgery. Varying concentration of dLECM (1, 4, and 8 mg/ml) were loaded into CG, and evaluation was done to get the optimized composition. Preliminary analysis on the microstructure, in-vitro degradation, and blood clot kinetics and in-vitro cytocompatibility showed that the CG with 4 mg/ml dLECM (CG-E4) was the most suitable composition for further consideration. The prepared CG-E4 spongy scaffold enhances fast post-operative recovery with a higher blood absorption and fast clotting time (~50 s). In addition, CG-E4 spongy scaffold implanted at rat liver wound showed desired biocompatibility as evidenced by reduced wound size, earlier bioabsorption and accelerated liver regeneration. In the present study, we demonstrated that, CG with dLECM spongy scaffold as a potential hemostatic material in the prevention of excessive hemorrhage during surgeries.

Fabrication, swelling behavior, and water absorption kinetics of genipin‐crosslinked gelatin–chitosan hydrogels

AbstractGelatin/chitosan hydrogels have attracted considerable attention over the last 2 decades in various fields of applications. In this paper, chemically crosslinked composite hydrogels with different gelatin‐to‐chitosan weight ratios were fabricated and crosslinked with different amounts of genipin via the solvent casting technique combined with freeze‐drying. Fourier‐transform infrared, scanning electron microscopy (SEM), liquid displacement method, and gravimetric analysis were used to examine the chemical, microstructural, and physical properties of the hydrogels. IR spectra confirmed the formation of covalent bonds between the amino groups of the parent's macromolecules and genipin. SEM micrographs indicated that the hydrogels possessed a highly porous structure with well‐defined pore geometries. The swelling capacity and degradation rate of the specimens reduced with increasing the amounts of chitosan and/or genipin. In‐depth swelling measurements revealed that the first‐order kinetic model was only applicable in the early stage of the swelling study; however, the water absorption behavior of the hydrogels was best described by the pseudo‐second‐order kinetic model (Schott's model) throughout the swelling experiment. The genipin‐crosslinked hydrogels were found to support MC3T3‐E1 cell proliferation. The results of this paper thus suggest the 1.5% genipin‐crosslinked gelatin/chitosan hydrogels as promising candidates for on‐demand drug delivery applications or more precisely osteoarthritis drug delivery systems.

Sensitized fluorescence and superluminescence of a dye in a functional chitosan–gelatin matrix

A method for the formation of a functional biopolymer matrix based on specific mixing of chitosan and gelatin is proposed. It makes it possible to obtain the binding complexes of organic dyes such as eosin (energy donor) and rhodamine C (acceptor) with chitosan that are advantageous for the realization of inductive-resonant electron excitation energy transfer between these dyes. An efficient sensitized steady-state fluorescence of rhodamine C and superluminescence of this dye under pulsed excitation were observed in this system. The obtained results can be used for the development of two-component solid-state dye lasers.

Cytotoxic and anti-inflammatory effects of chitosan and hemostatic gelatin in oral cell culture.

Chitosan is a biopolymer with bactericidal/bacteriostatic effect, biocompatible and biodegradable. It has been used in tissue engineering to replace tissues partially or completely by releasing bioactive materials or influencing cell growth, usually in regenerative medicine and dentistry. The aim of this study was to evaluate the cytotoxic and anti-inflammatory effect of chitosan alone or with hemostatic gelatin (Spongostand®) in cultures of human pulp cells (HPC), human gingival fibroblasts (HGF) and mouse pre-osteoblasts (MC3T3-E1, ATCC). HPC and HGF were isolated from patients. Cells were subcultured in DMEM. Chitosan was inoculated at different concentrations (0-0.5%) and hemostatic gelatins impregnated with chitosan (0.19%) were placed directly in the presence of cells and incubated for 24 hours. Cell viability was determined by MTT method and mean cytotoxic concentration (CC50) was calculated from the dose-response curve. Anti-inflammatory effect was calculated from the in vitro gingivitis model induced with interleukin 1beta (IL-1β) in HGF and protein detection. The data were subjected to Shapiro-Wilk, Kruskal-Wallis and Mann-Whitney tests. Experiments were performed in triplicate of three independent assays. Cell viability of HPC, HGF and MC3T3-E1 in contact with chitosan decreased significantly (p<0.05). The HPC were the most sensitive (CC50= 0.18%), followed by HGF (CC50= 0.18%) and MC3T3-E1 (CC50= 0.19%). The cytotoxicity of gelatins impregnated with chitosan decreased cell viability of HGF and HPC by 11% and 5%, respectively. The proinflammatory effect was reduced significantly in the gingivitis model. To conclude, chitosan induces moderate cytotoxic effects alone or with hemostatic gelatin at 0.19%, in dose-dependent manner, with anti-inflammatory effects on human gingival fibroblasts. The use of chitosan as a biomaterial can be an excellent choice for use in regenerative dentistry.

Synthesis and Characterization of Porous, Electro-Conductive Chitosan-Gelatin-Agar-Based PEDOT: PSS Scaffolds for Potential Use in Tissue Engineering.

Herein we report the synthesis and characterization of electro-conductive chitosan–gelatin–agar (Cs-Gel-Agar) based PEDOT: PSS hydrogels for tissue engineering. Cs-Gel-Agar porous hydrogels with 0–2.0% (v/v) PEDOT: PSS were fabricated using a thermal reverse casting method where low melting agarose served as the pore template. Sample characterizations were performed by means of scanning electron microscopy (SEM), attenuated total reflectance–Fourier transform infrared spectroscopy (ATR–FTIR), X-ray diffraction analysis (XRD) and electrochemical impedance spectroscopy (EIS). Our results showed enhanced electrical conductivity of the cs-gel-agar hydrogels when mixed with DMSO-doped PEDOT: PSS wherein the optimum mixing ratio was observed at 1% (v/v) with a conductivity value of 3.35 × 10−4 S cm−1. However, increasing the PEDOT: PSS content up to 1.5 % (v/v) resulted in reduced conductivity to 3.28 × 10−4 S cm−1. We conducted in vitro stability tests on the porous hydrogels using phosphate-buffered saline (PBS) solution and investigated the hydrogels’ performances through physical observations and ATR–FTIR characterization. The present study provides promising preliminary data on the potential use of Cs-Gel-Agar-based PEDOT: PSS hydrogel for tissue engineering, and these, hence, warrant further investigation to assess their capability as biocompatible scaffolds.

Multifunctional palygorskite@ZnO nanorods enhance simultaneously mechanical strength and antibacterial properties of chitosan-based film

A general and effective strategy was developed for improving simultaneously the mechanical strength and antibacterial performance of biopolymer-based films. The well-dispersed zinc oxide (ZnO) nanoparticles were in-situ loaded on non-toxic natural palygorskite (PAL) nanorod to form an antibacterial PAL@ZnO composite nanorod, which can be embedded into chitosan/gelatin (CS/GL) film to produce the composite films with noticeably enhanced mechanical properties and antibacterial activity against S. aureus and E. coli bacteria (inhibition zones are 21.82 ± 0.95 mm and 16.36 ± 1.64 mm, respectively). The toughness of films enhances to 35.13 ± 0.95 MPa and the moisture uptake decreases to 23.74 ± 0.02% after embedding 3% and 9% of PAL@ZnO, respectively. In addition, incorporating PAL@ZnO nanorods also significantly enhanced the water resistance, and thermal stability of film. This work provides an alternative way for the development of antibacterial films with potential applications in many fields such as food packing.

Fabrication and Evaluation of Alginate/Bacterial Cellulose Nanocrystals-Chitosan-Gelatin Composite Scaffolds.

It is common knowledge that pure alginate hydrogel is more likely to have weak mechanical strength, a lack of cell recognition sites, extensive swelling and uncontrolled degradation, and thus be unable to satisfy the demands of the ideal scaffold. To address these problems, we attempted to fabricate alginate/bacterial cellulose nanocrystals-chitosan-gelatin (Alg/BCNs-CS-GT) composite scaffolds using the combined method involving the incorporation of BCNs in the alginate matrix, internal gelation through the hydroxyapatite-d-glucono-δ-lactone (HAP-GDL) complex, and layer-by-layer (LBL) electrostatic assembly of polyelectrolytes. Meanwhile, the effect of various contents of BCNs on the scaffold morphology, porosity, mechanical properties, and swelling and degradation behavior was investigated. The experimental results showed that the fabricated Alg/BCNs-CS-GT composite scaffolds exhibited regular 3D morphologies and well-developed pore structures. With the increase in BCNs content, the pore size of Alg/BCNs-CS-GT composite scaffolds was gradually reduced from 200 μm to 70 μm. Furthermore, BCNs were fully embedded in the alginate matrix through the intermolecular hydrogen bond with alginate. Moreover, the addition of BCNs could effectively control the swelling and biodegradation of the Alg/BCNs-CS-GT composite scaffolds. Furthermore, the in vitro cytotoxicity studies indicated that the porous fiber network of BCNs could fully mimic the extracellular matrix structure, which promoted the adhesion and spreading of MG63 cells and MC3T3-E1 cells on the Alg/BCNs-CS-GT composite scaffolds. In addition, these cells could grow in the 3D-porous structure of composite scaffolds, which exhibited good proliferative viability. Based on the effect of BCNs on the cytocompatibility of composite scaffolds, the optimum BCNs content for the Alg/BCNs-CS-GT composite scaffolds was 0.2% (w/v). On the basis of good merits, such as regular 3D morphology, well-developed pore structure, controlled swelling and biodegradation behavior, and good cytocompatibility, the Alg/BCNs-CS-GT composite scaffolds may exhibit great potential as the ideal scaffold in the bone tissue engineering field.