Chitosan-poly Vinyl Alcohol Research Articles

Amygdalin/chitosan-polyvinyl alcohol/cerium-tannic acid hydrogel as biodegradable long-time implant for cancer recurrence care applications: An in vitro study

Cancer recurrence following surgery is a serious and worrying problem for the patient. Common treatment strategies, such as chemotherapy, radiotherapy, and surgery, are restricted because of low uptake of the drugs, poor pharmacokinetic properties, and toxicity issues for healthy tissues. The development of engineering platforms for improving the postoperative treatment of cancer can help solve this problem. In this study, the ceria-tannic acid nanoparticles (CeTA-NPs) were successfully synthesized and characterized. Chitosan-polyvinyl/alcohol (CS-PVA) hydrogels containing CeTA NPs (CS-PVA/CeTA) and amygdalin as an anticancer substance were fabricated using freeze-thaw and immersion-drying techniques. The swelling and degradation behaviors, antibacterial activity, and biocompatibility of as-prepared hydrogel were done. The apoptotic effects of amygdalin/CS-PVA/CeTA hydrogel were evaluated by flow cytometry technique on a human colorectal cancer (SW-480) cell line. The CeTA-NPs were investigated as antibacterial and cross-linker agents for greater stability of the hydrogel network. The CS-PVA/CeTA hydrogel demonstrated good safety and antibacterial activity. The results of swelling and biodegradation suggest that CS-PVA/CeTA hydrogels can inspire long-time application. The anticancer effects of the amygdalin/CS-PVA/CeTA hydrogel were confirmed by apoptosis results. Hence, amygdalin/CS-PVA/CeTA hydrogel can be a promising candidate for long-time biomedical application.

Experimental investigations on PVA/chitosan and PVA/chitin films for active food packaging using Oxytenanthera abyssinica lignin nanoparticles and its UV-shielding, antimicrobial, and antiradical effects

This study investigated the effect of adding lignin nanoparticles (LNPs) derived from Oxytenanthera abyssinica via alkali-acid nanoprecipitation method to polyvinyl alcohol/chitosan (PVA/CI) and polyvinyl alcohol/chitin (PVA/CH) films for the active food packaging applications. Adding LNPs at concentrations of 1 % and 3 % improved the films' thermal stability and mechanical properties. The lowest water solubility and moisture content were observed in PVA/CI/LNPs films. LNPs exhibited effective 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activities, with the highest values observed in PVA/CH/LNPS and PVA/CI/LNPS films with values of 87.47 and 88.74 % respectively. The addition of LNPs also improved the UV-blocking abilities of the films. PVA/CH/LNP3 and PVA/CI/LNP3 have the smallest percentage transmission values of 3.34 % and 0.86 % in the UV range. The overall migration of dietary stimulants was lower in PVA/CI/LNPS and PVA/CH/LNPS films compared to PVA film. Antibacterial tests demonstrated the inhibitory capacity of the synthesized biofilms against both gram-positive and negative bacterial species, with the highest inhibitory value of 26 mm. The study suggests that PVA/CH/LNPS and PVA/CI/LNPS films have potential applications as active food packaging materials and can be explored in other potential applications such as drug delivery, tissue engineering, wound healing, and slow-release urea fertilizer development.

Radiographic evaluation of alveolar ridge preservation using a chitosan/polyvinyl alcohol nanofibrous matrix: A randomized clinical study

The objective of this randomized clinical trial (RCT) was to assess the effectiveness of electrospun chitosan/polyvinyl alcohol (CS/PVA) nanofibrous scaffolds in preserving the alveolar ridge and enhancing bone remodeling following tooth extraction when compared to a control group. In this split RCT, 24 human alveolar sockets were randomly assigned to two groups, with 12 sockets receiving CS/PVA nanofibrous scaffold grafts (test group) and 12 left to heal by secondary intention as the control group. Cone-beam computed tomography (CBCT) was performed at two different time points: immediately after extraction (T0) and 4 months post-extraction (T4). After 4 months, linear vertical and horizontal radiographic changes and bone density of extraction sockets were assessed in both the test and control groups. The RCT included 12 patients (4 male and 8 female) with a mean age of 24 ± 3.37 years. The test group had a significantly lower mean vertical resorption vs the control group, with a mean difference of 1.1 mm (P < 0.05). Similarly, the control group's mean horizontal bone resorption was −2.01 ± 1.04 mm, while the test group had a significantly lower mean of −0.69 ± 0.41 mm, resulting in a mean difference of 1.35 mm (P < 0.05). Furthermore, the study group exhibited a significant increase in bone density (722.03 ± 131.17 HU) after 4 months compared to the control group (448.73 ± 93.23 HU). In conclusion, we demonstrated within the limitations of this study that CS/PVA nanofibrous scaffold significantly limited alveolar bone resorption horizontally and vertically and enhanced bone density in alveolar sockets after 4 months when compared to results in the control group (TCTR20230526005).

Development of curcumin-containing polyvinyl alcohol/chitosan active/intelligent films for preservation and monitoring of Schizothorax prenanti fillets freshness

Active/intelligent films for the preservation and monitoring of Schizothorax prenanti fillets freshness were prepared by combining curcumin (CUR) with polyvinyl alcohol/chitosan (PVA/CS) matrix. SEM images showed that the CUR with a maximum content of 1.5 % (w/w) was evenly distributed in the composite matrix. The addition of CUR did not affect the chemical structure of PVA/CS matrix, as confirmed by FTIR investigation. When 1.5 % (w/w) CUR was added, the water vapor barrier property, tensile strength and antioxidant activity of the composite film were the best, which were 5.38 ± 0.25 × 10−11 g/m·s·Pa, 62.05 ± 1.68 MPa and 85.50 ± 3.63 %, respectively. Water solubility of PVA/CS/CUR-1.5 % film was reduced by approximately 27 % compared to PVA/CS film. After adding CUR, the antibacterial properties of the composite film increased significantly. Although the addition of CUR reduced the biodegradability of PVA/CS film, the PVA/CS/CUR-1.5 % film degraded >60 % within 5 weeks. By measuring pH, weight loss, total volatile base‑nitrogen (TVB-N), thiobarbituric acid reactive substances (TBARS), and total viable counts (TVC), the preservation effect of the composite films on the fish freshness was evaluated. The fish shelf life treated by PVA/CS/CUR-1.5 % film expanded from 3–6 days to 12–15 days at 4 °C. In addition, when PVA/CS/CUR-1.5 % film was used to monitor the fish freshness, it exhibited clear color fluctuations, from yellow to orange and to red, corresponding to first-grade freshness, second-grade freshness, and rottenness of the fish, respectively. As a result, the films can be successfully used for Schizothorax prenanti fillets preservation and deterioration monitoring.

Preparation of polyvinyl alcohol/chitosan nanofibrous films incorporating graphene oxide and lanthanum chloride by electrospinning method for potential photothermal and chemical synergistic antibacterial applications in wound dressings

Electrospun fibres have been widely used as skin dressings due to their unique structur. However, due to the lack of intrinsic antimicrobial activity, it is easy for the wound to become infected. Bacterial infection, which leads to chronic inflammation, severely hinders the normal process of skin regeneration. In this study, a polyvinyl alcohol/chitosan (PVA/CS) composite films with chemical sterilization and near-infrared (NIR) photothermal antibacterial activity was fabricated by electrospinning. Graphene oxide (GO), a photosensitiser, was incorporated into the films, and lanthanum chloride (Lacl3) as a chemical antibacterial agent was also doped in the electrospun films. The structure, morphology, mechanical properties, wettability, and antimicrobial and photothermal antibacterial activity of the PVA/CS-based fibre films were investigated. The results showed that the addition of Lacl3 to the PVA/CS/GO nanofibres (PVA/CS/GO-La) improved the hydrophilicity, tensile strength and resistance to elastic deformation of the nanofibres. The PVA/CS/GO-La12.5 mM sample exhibited the best antibacterial performance, showing high inhibition against Staphylococcus aureus (82% antibacterial efficacy) and Escherichia coli (99.7% antibacterial efficacy). Furthermore, the antibacterial efficacy of the films surface was further enhanced after exposure to NIR light (808 nm, 0.01 W) for 20 min. In addition, the nanofibre films showed no cytotoxicity against human skin fibroblasts (HSFs), indicating its potential application in the field of broad-spectrum antibacterial materials.

Curcumin-Laden Crosslinked Chitosan–PVA Films: The Synergistic Impact of Genipin and Curcumin on Accelerating Wound Closure

AbstractWound dressings play a critical role in healing by maintaining a moist environment and protecting against infection. Here, we fabricate crosslinked films of chitosan–polyvinyl alcohol–genipin–curcumin to investigate the synergistic wound-healing effect of genipin and curcumin. The chemical bonding, morphology, strength, water retention capacity, curcumin release characteristics, and cytotoxicity of the films were investigated. The results showed a 192% increase in tensile strength and good water retention, and the infrared analysis and scanning electron microscopy micrographs confirmed genipin crosslinking and the presence of curcumin in the films, whose morphology was uniform and continuous. The curcumin-loaded films were found to have insignificant cytotoxicity against 3T3 fibroblast cells, proving their biocompatibility. The curcumin dissolution tests determined the amount of curcumin released from the films with time, and assessed the release characteristics to be sustained at all pH levels. In vivo trials were carried out on rodents to evaluate the wound-healing effects of the films, and the results showed that the curcumin-incorporated crosslinked films accelerated wound healing compared to the uncrosslinked and curcumin-absent films, confirming their effectiveness for wound healing.

Comparative Study of ZnO-and-TiO2-Nanoparticles-Functionalized Polyvinyl Alcohol/Chitosan Bionanocomposites for Multifunctional Biomedical Applications.

This study aimed to synthesize chitosan/polyvinyl alcohol (CS/PVA)-based zinc oxide (ZnO) and titanium dioxide (TiO2) hybrid bionanocomposites (BNCs) and observe their comparative accomplishment against the skin cancer cell line, A431, and antioxidant potential. CS was blended with PVA to form polymeric films reinforced with the immobilization of ZnO and TiO2 nanoparticles (NPs), separately. The optimization of the BNCs was done via physicochemical studies, viz. moisture content, swelling ratio, and contact angle measurements. The free radical scavenging activity was observed for 1,1-diphenyl-2-picryl-hydrazyl, and the antibacterial assay against the Escherichia coli strain showed a higher zone of inhibition. Furthermore, the anticancer activity of the synthesized BNCs was revealed against the skin cancer cell line A431 under varying concentrations of 50, 100, 150, 200, and 300 μg/mL. The anticancer study revealed a high percent of cancerous cell inhibition (70%) in ZnO BNCs as compared to (61%) TiO2 BNCs in a dose-dependent manner.

Microporous chitosan/polyvinyl alcohol based active packaging materials with integrated gas-transmission, radiation-cooling, anti-microbial, and ultraviolet shielding features

Active packaging materials transform the packaging from a passive barrier to active control, responding to consumers' demand for safer, healthier, and higher quality food and prolonging the shelf life of foods. Herein, a novel microporous chitosan/polyvinyl alcohol (CS/PVA) based biodegradable active packaging material (microporous membrane doped with 0.3 wt% nanometer TiO2, referred as MT3) was nanoengineered with integrated gas transmission, radiation cooling, anti-microbial and quality control characteristics. The particle leaching method realized the on-demand microporous structure, enabling an impressive CO2 permeability. Furthermore, TiO2 nanoparticles were filled in MT3 as functional fillers to achieve good radiation cooling, anti-bacterial and ultraviolet shielding functions. In addition, MT3 exhibited the typical features of packaging materials, such as sufficient hydrophobicity and mechanical and barrier performances. Interestingly, the superficial temperature of MT3 reduced by ∼ 6.4 °C due to its excellent radiation-cooling properties under a sub-ambient atmosphere. Thus, the on-demand comprehensive material design enabled MT3 to exhibit an enhanced shelf life of 168 h, which is difficult to achieve with conventional preservative films at room temperature. These results encourage the further use of MT3 films as multi-functional active packaging materials. This study provides a green and feasible method for the production of promising active packaging functional materials, which can be widely used in fresh fruit and vegetable preservation packaging.

Ultrasensitive QCM sensor development for monitoring of methyl orange dye in aqueous phase based on novel cross-linked chitosan/PVA/GO/Ce-ZnO nanocomposite film

In this study, chitosan/polyvinyl alcohol (CS/PVA) nanocomposite hydrogels were produced using the solution casting method due to their non-toxic and biocompatible nature. The best composition was chosen and cross-linked with glutaraldehyde, after which a certain amount of graphene oxide nanosheets (GO NS) and cerium doped zinc oxide nanoparticles (Ce-ZnO NPs) were added to develop nanocomposite hydrogel films (NCs). X-ray diffractometer (XRD), scanning electron microscope (SEM), energy-dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM), atomic force microscopy (AFM), Fourier-transform infrared spectroscopy (FTIR), N2 adsorption–desorption isotherm, Raman spectroscopy, and thermogravimetric analyzer (TGA/DTG) were used to characterize the films. The synthesized composites were also evaluated for sensitivity towards methyl orange (MO) dye based on the quartz crystal microbalance (QCM) technique at different pH of MO solution. XRD results revealed that all films whether CS film or the blend CS/PVA/GO and CS/PVA/GO/Ce-ZnO films exhibited good crystallinity. The SEM images depicted the surface morphology of films, which clarified the adding effect of GO NS and Ce-ZnO NPs on the surface morphology of CS/PVA films. While the EDS analysis demonstrated the elemental composition of CS/PVA/GO/Ce-ZnO film. In the same context, the TEM images emphasized the results obtained by the SEM examination and showed no phase separation of the polymers. Whereas AFM showed an increase in surface roughness with adding of GO NS, while was decreased in the case of Ce-ZnO NPs addition. Surface area and pore size distribution results revealed significant differences due to the addition of GO NS and Ce-ZnO NPs to the CS/PVA matrix. The chemical structure of all films was investigated using the Raman shift and their thermal behaviours were also analysed. Finally, the results of QCM sensor-based prepared films showed that the inclusion of GO NS and Ce-ZnO NPs boosted the monitoring performance of sensor films towards MO dye. Furthermore, the sensors-based nanocomposite films presented the same monitoring attitude for MO at different pH.

A calcium peroxide incorporated oxygen releasing chitosan-PVA patch for Diabetic wound healing

Impaired wound healing is a major healthcare problem in patients with diabetes often resulting in gangrene, microbial infection and amputation of affected limb. The delay or absence in healing process arises from several abnormalities, among them chronic hypoxia is a major concern due to its associated issues such as lack of collagen deposition, epithelization, fibroplasia, angiogenesis, and resistance to infections at the wound site. To address hypoxia, delivery of oxygen at the wound site through oxygen releasing agents have been proven to be effective therapeutics. Several oxygen releasing nanoparticles such as Sodium Percarbonate (SPC), Calcium Peroxide (CPO), Hydrogen Peroxide, Magnesium Peroxide (MPO) have been investigated in wound healing application. However, the uncontrolled/burst release of these nanotherapeutic agents and its accompanied cytotoxicity pose a barrier in expediting the healing process. In this study, a Chitosan-Polyvinyl alcohol (CS-PVA) based hydrogel containing oxygen releasing nanoparticle, calcium peroxide (CPO) was constructed to provide a slow and sustained delivery of oxygen for at least 5 days. In-vitro cell culture studies with this material using fibroblast and endothelial cell line exhibited improved biocompatibility, cell viability and enhanced proliferation in comparison with the control group. Additionally, cell migration study using scratch assay method showed superior cell migration ability of our proposed materials. Furthermore, In vivo study using diabetic rat model showed accelerated wound closure rate compared to untreated control wounds.

Chitosan/polyvinyl alcohol-based nanocomposite films incorporated with L-Glu surface functionalized ZnO NPs: Physicochemical, photocatalytic, antimicrobial and antioxidant properties evaluation

Present work describes fabrication of active nanocomposite films (NCs) by incorporation of functionalized ZnO NPs (2, 4, 6 and 8 wt%) onto blended polymers chitosan/polyvinyl alcohol (CS/PVA). The required ZnO NPs prepared for this work by novel biogenic method using water extract of mango peel ash (WEMPA), and surface functionalized by L-Glutamic acid (L-Glu) and composite films were prepared by solvent casting method. The barrier properties, tensile strength, and antioxidant activity of the prepared films showed improved by addition of different percentage content of the ZnO-L-Glu NPs. The photocatalytic activity of the prepared films were confirmed by degradation of the methylene blue dye up to 98% in 120 min duration under sun light expose noticed. Further, prepared NC films were tested for inhibition to S. aureus (gram-positive) and E. coli (gram-negative) bacteria, and emerged as a good antibacterial. Therefore, the new CS/PVA/ZnO NPs-Glu films prepared in this work (CPZG), could be used for the food packaging as well as photo decolorization for the environmental remediation applications.

Investigating of the influence of zinc oxide nanoparticles morphology on the properties of electrospun polyvinyl alcohol/chitosan (PVA/CS) nanofibers

In recent years, investigating of the effect of nanoparticles with different morphologies in therapeutic applications has attracted the attention of many researchers. In this research, the effect of adding zinc oxide nanoparticles with a completely new morphology in the improving the properties of PVA/CS nanofibers as a wound dressing are investigated. Zinc oxide nanoparticles were synthesized using the co-precipitation method. Scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Zeta potential (ZP), and dynamic light scattering (DLS) were used to characterize the synthesized particles. Using Experimental Design software resulted in the preparation of defect-free nanoscale fibers and beads by optimizing factors such as voltage, feed rate and PVA/CS mixing ratio. After determining the optimal conditions, several weight percentages of ZnO nanoparticles with pyramidal rod and star-like morphologies were introduced to the electrospinning solution. The properties of the fabricated nanofibers were also analyzed by SEM, FTIR, tensile testing, thermal analysis, antibacterial testing, and in vivo wound healing in mice. The tensile tests revealed that the addition of zinc oxide nanoparticles with pyramidal rod morphology increased the mechanical strength of PVA/CS nanofibers, while star-like ZnO decreased the mechanical strength. Furthermore, incorporating ZnO in PVA/CS nanofibers greatly enhances their heat resistance. The antibacterial test results revealed that fibers containing zinc oxide nanoparticles have significant antibacterial activities. In vivo wound healing tests demonstrated that PVA/CS/ZnO nanofibers enhanced wound healing compared to PVA/CS nanofibers. Histopathological investigation revealed that epidermal regeneration is complete in samples containing ZnO nanoparticles. The present study shows that PVA/CS nanofibers containing zinc oxide nanoparticles with pyramidal rod morphology have great potential in wound healing.

Analysis Of the Ripping Rate of Banana Fruit Coated with Biofilm Based on Polyvinyl Alcohol Chitosan Composite

Analysis Of the Ripping Rate of Banana Fruit Coated with Biofilm Based on Polyvinyl Alcohol Chitosan Composite

(TiO2/Ag nanoparticles)@(chitosan-polyvinyl alcohol) core-shell nanofibers as novel anticorrosion and antibacterial improvers for epoxy coating systems

(TiO2/Ag nanoparticles)@(chitosan-polyvinyl alcohol) core-shell nanofibers as novel anticorrosion and antibacterial improvers for epoxy coating systems

Electrospun polyvinyl alcohol-chitosan dressing stimulates infected diabetic wound healing with combined reactive oxygen species scavenging and antibacterial abilities

Diabetic wounds (DW) are constantly challenged by excessive reactive oxygen species (ROS) accumulation and susceptibility to bacterial contamination. Therefore, the elimination of ROS in the immediate vicinity and the eradication of local bacteria are critical to stimulating the efficient healing of diabetic wounds. In the current study, we encapsulated mupirocin (MP) and cerium oxide nanoparticles (CeNPs) into a polyvinyl alcohol/chitosan (PVA/CS) polymer, and then a PVA/chitosan nanofiber membrane wound dressing was fabricated using electrostatic spinning, which is a simple and efficient method for fabricating membrane materials. The PVA/chitosan nanofiber dressing provided a controlled release of MP, which produced rapid and long-lasting bactericidal activity against both methicillin-sensitive S. aureus (MSSA) and methicillin-resistant S. aureus (MRSA) strains. Simultaneously, the CeNPs embedded in the membrane exhibited the desired ROS scavenging capacity to maintain the local ROS at a normal physiological level. Moreover, the biocompatibility of the multifunctional dressing was evaluated both in vitro and in vivo. Taken together, PVA-CS-CeNPs-MP integrated the desirable features of a wound dressing, including rapid and broad-spectrum antimicrobial and ROS scavenging activities, easy application, and good biocompatibility. The results validated the effectiveness of our PVA/chitosan nanofiber dressing, highlighting its promising translational potential in the treatment of diabetic wounds.

Modification of the Structure and Linear/Nonlinear Optical Characteristics of PVA/Chitosan Blend through CuO Doping for Eco-Friendly Applications.

The solution casting technique is utilized to fabricate blank and CuO-doped polyvinyl alcohol/chitosan (PVA/CS) blends for eco-friendly applications. The structure and surface morphologies of prepared samples were explored by Fourier transform infrared (FT-IR) spectrophotometry and scanning electron microscopy (SEM), respectively. FT-IR analysis reveals the incorporation of CuO particles within the PVA/CS structure. SEM analysis exposes the well-dispersion of CuO particles in the host medium. The linear/nonlinear optical characteristics were found on the basis of UV-visible-NIR measurements. The transmittance of the PVA/CS decreases upon CuO increasing to 20.0 wt%. The optical bandgap (Eg dir./Eg ind.) decreases from 5.38/4.67 eV (blank PVA/CS) to 3.72/3.12 eV (20.0 wt% CuO-PVA/CS). An obvious improvement in the optical constants of the PVA/CS blend is achieved by CuO doping. The Wemple-DiDomenico (WDD) and Sellmeier oscillator models were utilized to examine the CuO role dispersion behavior of the PVA/CS blend. The optical analysis shows clear enrichment of the optical parameters of the PVA/CS host. The novel findings in the current study nominate CuO-doped PVA/CS films for applications in linear/nonlinear optical devices.

Polyvinyl Alcohol-Chitosan Scaffold for Tissue Engineering and Regenerative Medicine Application: A Review.

Tissue engineering and regenerative medicine (TERM) holds great promise for addressing the growing need for innovative therapies to treat disease conditions. To achieve this, TERM relies on various strategies and techniques. The most prominent strategy is the development of a scaffold. Polyvinyl alcohol-chitosan (PVA-CS) scaffold emerged as a promising material in this field due to its biocompatibility, versatility, and ability to support cell growth and tissue regeneration. Preclinical studies showed that the PVA-CS scaffold can be fabricated and tailored to fit the specific needs of different tissues and organs. Additionally, PVA-CS can be combined with other materials and technologies to enhance its regenerative capabilities. Furthermore, PVA-CS represents a promising therapeutic solution for developing new and innovative TERM therapies. Therefore, in this review, we summarized the potential role and functions of PVA-CS in TERM applications.

Hydrogel-regulated interfacial polymerization: A gateway to effective nanostructure tuning of polyamide nanofiltration membranes

Controllable interfacial polymerization (IP) is eminently desirable for the preparation of high-performance nanofiltration (NF) membranes to address the worldwide water scarcity. Herein, we report a facile and versatile approach to prepare novel polyamide (PA) NF membranes via a hydrogel-assisted IP process. The piperazine (PIP) diffusion was precisely controlled by tailoring the viscosity of the introduced chitosan/polyvinyl alcohol (CS/PVA) hydrogel via adjusting the hydrogel composition and crosslinking degree. Due to the synergistic effect of the decreased thickness and improved surface hydrophilicity of the PA layer formed atop hydrogel, the hydrogel-regulated thin film composite (TFC-hg) membrane exhibited a high water permeance of 15.5 L m−2 h−1 bar−1, which was 2.5 times of that of the control membrane. Meanwhile, the TFC-hg membrane achieved a Na2SO4 rejection of 99.1 % due to the highly cross-linked PA separation film. This work offers a simple and highly effective strategy for constructing high-performance TFC NF membranes toward efficient water treatment.

Fabrication and characterisation of poly(vinyl alcohol)/chitosan scaffolds for tissue engineering applications

In this study, poly(vinyl alcohol)/chitosan (PVA/CS) scaffolds were fabricated by freeze-drying method and the characterisations of obtained scaffolds were carried out to analyse the suitability of the product for biomedical applications such as tissue engineering. The effect of initial PVA concentrations and their hydrolysis degrees, the addition of different molecular weights (MWs) of CS along with the blending ratio of PVA/CS were studied. Fourier transmission infrared (FTIR) spectroscopy showed the presence of chemical bonds in PVA and PAV/CS scaffolds and the energy dispersive X-ray (EDX) spectroscopy confirmed the existence of the chemical element nitrogen in PVA/CS scaffolds. The stability of scaffolds under physiological conditions was studied by swelling and degradation tests, which demonstrated the effect of initial PVA concentration and CS addition on the water resistance of scaffolds. Scanning Electron Microscopy (SEM) images showed highly porous structures which became more uniform in pore size with the addition of CS. The mechanical properties of dry and hydrated scaffolds were also investigated by an unconfined compression test and the compressive modulus and maximum stress at 20% strain were calculated through stress–strain curves. The in-depth characterisation of scaffolds showed that the initial concentration and blending ratio of PVA/CS can be adjusted to tailor the desired properties of scaffolds for different biomedical applications.

Preparation of a composite-based thin film and its sensing application for detecting beef freshness

In order to improve the stability of polyphenols anthocyanidins as freshness indicator in food packaging, in this study, gellan (GL), grape-skin anthocyanidins (GSAC) and chitosan-polyvinyl alcohol (CHPA) were prepared as a composite film to protect beef and indicate the beef freshness for visual detection. The results indicated that the composite film appears good mechanical properties. The results of scanning electron microscopy showed that when the composite film were added into CHPA, the structure compatibility and stability of the film was the best. Then the complicate film was used to indicate the beef freshness and the beef was stored at 4 °C, the total volatile base nitrogen content of beef had increased continuously with the extension of storage time. After 6 days, the total volatile base nitrogen content was 35.65 mg/100 g, the thiobarbituric acid reaction product value was 1.005 mg, and pH value was 6.96. It can be seen directly with the naked eyes that the color of the film changed from dark red to mauve, and finally to blue brown, suggesting that the beef had been rotten. To sum up, the composite film made up of CHPA and gellan (GL) anthocyanin (AC) can not only reduce the oxidation of anthocyanin and improve its stability, but also be used as an indicator of meat freshness.