Wound Dressing Applications Research Articles

Poly(vinyl alcohol)/Pullulan Composite Hydrogels as a Potential Platform for Wound Dressing Applications.

Hydrogels are 3D networks with an excellent ability to retain a high amount of water or biological fluids, representing suitable candidates for wound dressing applications. They can provide a protective barrier and a moist environment, facilitating wound treatment. The present paper focuses on physical hydrogels obtained from poly(vinyl alcohol) (PVA) and pullulan (PULL) mixtures in different weight ratios by using the freezing/thawing method. Hybrid hydrogels of similar polymer compositions were prepared in the presence of 0.5% Laponite® RD. The influence of polysaccharide and clay addition on the properties of PVA hydrogels was investigated. Scanning electron microscopy showed evidence of the inner porous structure. The viscoelastic properties were investigated in different shear conditions and revealed the influence of the hydrogel composition on the network strength. The swelling behavior was followed in physiological saline solutions at 37 °C and pH = 7.4. For all samples, a quasi-Fickian diffusion mechanism was found. The delivery of neomycin sulfate was studied in similar conditions as for the swelling tests (0.15 M NaCl solutions; 37 °C; pH = 7.4) and different kinetic models were used to determine the release mechanism. The Peppas-Sahlin approach described very well the in vitro drug release mechanism from the polymeric hydrogels in the absence of clay. However, the hybrid polymer/clay hydrogels showed the best fit with the Korsmeyer-Peppas model. According to the present study, the porous membranes containing 40-60% PULL (in absence of clay) are suitable for the release of therapeutic agents at wound sites in physiological conditions.

Effects of Poloxamers as Excipients on the Physicomechanical Properties, Cellular Biocompatibility, and In Vitro Drug Release of Electrospun Polycaprolactone (PCL) Fibers.

Electrospun microfibers are emerging as one of the advanced wound dressing materials for acute and/or chronic wounds, especially with their ability to carry drugs and excipients at a high loading while being able to deliver them in a controlled manner. Various attempts were made to include excipients in electrospun microfibers as wound dressing materials, and one of them is poloxamer, an amphiphilic polymer that exhibits wound debridement characteristics. In this study, we formulated two types of poloxamers (i.e., P188 and P338) at 30% (w/w) loading into electrospun polycaprolactone (PCL) fibers to evaluate their physicomechanical properties, biocompatibility, and in vitro drug release of a model drug. Our findings showed that the incorporation of poloxamers in the PCL solutions during electrospinning resulted in a greater "whipping" process for a larger fiber deposition area. These fibers were mechanically stiffer and stronger, but less ductile as compared to the PCL control fibers. The incorporation of poloxamers into electrospun PCL fibers reduced the surface hydrophobicity of fibers according to our water contact angle studies and in vitro degradation studies. The fibers' mechanical properties returned to those of the PCL control groups after "dumping" the poloxamers. Moreover, poloxamer-loaded PCL fibers accelerated the in vitro release of the model drug due to surface wettability. These poloxamer-loaded PCL fibers were biocompatible, as validated by MTT assays using A549 cells. Overall, we demonstrated the ability to achieve a high loading of poloxamers in electrospun fibers for wound dressing applications. This work provided the basic scientific understanding of materials science and bioengineering with an emphasis on the engineering applications of advanced wound dressings.

Fabrication and Characterization of Polylactic Acid Electrospun Wound Dressing Modified with Polyethylene Glycol, Rosmarinic Acid and Graphite Oxide.

Polylactic acid (PLA) is a biodegradable polymer made from natural sources, and its electrospinning (e-spinning) nanofiber membrane doped with antibacterial ingredients is widely used in the field of medical dressings. In this research, 9 wt% of rosmarinic acid (RosA) and 0.04 wt% of graphite oxide (GO) with synergistic antibacterial activity were introduced into the e-spinning PLA precursor solution, and the obtained PLA nanofiber membrane showed good antibacterial properties and wound healing effects. At the same time, a nonionic amphiphilic polymer, polyethylene glycol (PEG), was also introduced into this system to improve the hydrophilicity of the e-spinning membrane for wound healing application. The morphological characterization showed the RosA/GO and PEG did not affect the e-spinning of PLA. The tests of mechanical performance and wettability demonstrated that PEG and RosA/GO incorporated in PLA have migrated easily to the surface of the fiber. The e-spun PLA/PEG/RosA/GO membrane showed good antibacterial activity and promoted initial wound healing quickly, which would be a promising application in wound dressing.

The Discovery of Drug Delivery from Development Film Forming Hydrogel for Wound Dressing Applications: A Systematic Review

Film Forming Hydrogel is a dosage form that changes shape to film by solvent evaporation after being applied to the wound area. This study aims to present a study to develop film-forming hydrogels with a brief description of the membrane properties formulated from biopolymers for wound application. Over the last ten years, much effort has been conducted to develop new artificial polymeric membranes that meet the demanding requirements for topical applications such as skin wound care. Therefore, this study represents the ideal polymer specifications for wound dressing membranes, such as cross-linked hydrogels compatible with wound dressings. The results of the analysis showed that single-component hydrogels have low mechanical strength. Therefore, recent trends offer composite or hybrid hydrogel membranes to achieve a typical wound with various requirements to meet the characteristic aspects of film-forming hydrogels.

Thermo-mechanical performance of nanostructured electrospun composites produced from poly(vinyl alcohol) and cellulosic compounds for potential uses as wound dressings

The purpose of this research was to analyze the morphology, thermal and mechanical properties of poly(vinyl alcohol) (PVA)-based electrospun mats reinforced with cellulose acetate (CA) or cellulose nanocrystalline (CNC) for potential applications in wound dressings. Bead-free and water-stable electrospun nanofibers made of blends of PVA and CA or CNC were successfully produced and crosslinked with glutaraldehyde vapor. Crosslinking slightly increased the nanofibers' diameters in order of 43 and 13% for 80/20 PVA/CA and PVA/CNC electrospun mats, respectively, while maintaining their bead-free morphology. Thermogravimetry (TGA) and differential scanning calorimetry (DSC) evaluations were employed to determine the miscibility and the thermal response of the uncrosslinked and crosslinked mats, reporting a reduction in mass loss upon addition of CA and CNC and upon crosslinking process. Polymers' powder and mats (before and after crosslinking) crystallinity was assessed by X-ray diffraction analysis (XRD). Crosslinked mats experienced a slight reduction in crystallinity compared to the uncrosslinked. Static and dynamic tensile strength tests revealed that CA and CNC doped mats enhanced the Young's modulus and lowered deformation at failure compared to pristine PVA electrospun mats. Data from storage modulus (E′) demonstrated the strength of the physical interactions formed between PVA and the cellulosic derivatives (either before and after crosslinking), highlighting the stiffness of CA (231.58 MPa for the 80/20 mat) and, particularly, CNC (742.04 MPa for the 80/20 mat). This research uncovered important information concerning the chemical and physical relation between polymeric matrices and additives, essential for the proper selection of materials for wound dressings production.

Sustainable one-pot synthesis of novel soluble cellulose-based nonionic biopolymers for natural antimicrobial materials

Novel soluble cellulose-based nonionic biopolymers (CIs) with enhanced antimicrobial properties and nonleachability were successfully produced using a sustainable one-pot synthesis method. Fourier transform infrared spectroscopy (FTIR), Nuclear magnetic resonance H-spectrometer (1H NMR), X-ray Photoelectron Spectroscopy (XPS), and Energy Dispersive Spectroscopy (EDS) results demonstrated that the cellulose (MCC) molecules combined with indole-3-acetic acid (IAA) via esterification to produce CIs with abundant terminal indole groups. The degree of substitution of the prepared CI3 reached 1.85 when the molar ratio of IAA to MCC molecules was 4:1. The prepared CI samples were characterized using X-ray diffractometer (XRD), Scanning Electronic Microscopy (SEM), Thermogravimetric Analysis (TGA), and other analysis techniques. Results indicated that after the MCC was grafted with IAA, its crystallinity decreased and solubility increased. After blending CI3 with polycaprolactone (PCL) to form cellulose-based antimicrobial (PCL–CI) films, the films showed good compatibility, preferable biological cell activity, and low water vapor permeability. When the CI3 content was 10%, the tensile strength of the produced PCL–CI10 film reached 9.96 MPa. Moreover, the prepared PCL–CI films exhibited good nonleachability after being immersed in water for 5 d. The disk diffusion assay revealed that the CIs and PCL–CI films had good antimicrobial and bactericidal effects against Gram-positive bacteria (Staphylococcus aureus) and Gram-negative bacteria (Escherichia coli). The minimal inhibitory concentration was 5 μg disk−1, significantly lower than that of traditional antibiotics and chitosan. The nonionic biopolymers are simple and efficient to prepare and ecofriendly as well as exhibit nontoxicity, good solubility, enhanced antimicrobial properties, and nonleachability, which can provide new ideas for developing natural biomass-based nonionic antimicrobial materials with potential applications in wound dressing, medical devices, and food packaging.

Morphological and Wettability Evaluation of Electrospun Polivinyl Alcohol (PVA) Nanofiber Membrane for Wound Dressing Application

Many researches have focused on producing electrospun nanofiber membranes (ENMs) aiming to speed up physiological events of wound healing. However, it is still a challenge to fabricate functional ENMs using electrospinning technique, taken into account various factors that may affect the fibers diameter such as polymer solution properties, electrospinning parameters and ambient conditions. This study aimed to evaluate the combined electrospinning process parameters and characterize the morphology and wettability of the electrospun polyvinyl alcohol (PVA) nanofiber membranes produced. Process parameters that were optimized include applied voltage, flow rate, and distance to collector. The fabrication of PVA nanofiber membranes was done at 21 kV, 2 mL/h and 10 cm after optimization. Surface morphology and fiber diameter were analyzed using a scanning electron microscope (SEM). The water contact angle was used to analyze wettability. Electrospun PVA nanofiber membranes showed continuous random fiber, no bead defect, hydrophilic surface and average fiber diameters between 265 ± 86 nm and 281 ± 90 nm. Smaller fiber diameter between 200-700 nm can enhance cell migration. It is suggested from this study that the optimized parameters have successfully produced electrospun PVA nanofiber membranes with suitable fiber diameter for cell migration and can direct cell response, thus can be applied as a wound dressing material.

Green synthesis of nano silver-embedded carboxymethyl starch waste/poly vinyl alcohol hydrogel with photothermal sterilization and pH-responsive behavior

Bacterial wound infections remain a significant health issue of great concern. Hence, there is a need to develop a novel material with antibacterial properties and smart functions. In this study, the effects of silver nanoparticles content (AgNPs) on properties of photothermal and pH-responsive nanocomposite hydrogels were investigated. The nanocomposite hydrogel samples were prepared using cassava starch waste modified by carboxymethylation (CMS), and mixed with poly vinly alcohol (PVA) and tannic acid (TA). The presence of AgNPs in the hydrogel samples enhanced antibacterial activities and photothermal conversion ability. The use of as-prepared hydrogel using 200 mM silver nitrate (H-AgNPs-200) combined with near infrared (NIR) radiation produced 100 % antibacterial efficiency for Escherichia coli (E.coli) and 98.2 % for Staphylococcus aureus (S.aureus). Furthermore, the H-AgNPs-200 also provided the highest storage modulus at 8.78 kPa. The obtained nanocomposite hydrogel was shown to exhibit pH-responsive release of TA. Under NIR radiation, higher release of TA at different pH was observed. The cytotoxicity study indicated that the nanocomposite hydrogels had good biocompatibility. Hence, the development of nanocomposite hydrogel-based CMS from cassava starch waste/PVA/AgNPs is a promising and sustainable approach where agro-waste product is used as the base material for medical application in wound dressing.

Mussel-Inspired PEDOT-Incorporated Gelatin-Based Conductive Hydrogel with Flexibility and Electroactivity to Accelerate Wound Healing In Vitro

Chronic wounds are associated with a metabolically imbalanced physiological microenvironment. However, conventional wound dressings are inadequate for treating chronic wounds due to their weak bioactivity. Electroactive wound dressings are essential for modulating a myriad of biological processes, particularly antioxidant activity and cell migration. Herein, we designed a conductive hydrogel with flexible, biodegradable, and electroactive properties using a mussel-inspired method. This conductive hydrogel was prepared by inducing poly(3,4-ethylenedioxythiophene) (PEDOT) in situ polymerization in the Hofmeister effect-assisted polydopamine-functionalized gelatin hydrogel (Gel-PDA/PEDOT). The hydrogel demonstrated robust mechanical properties with compressive and tensile strengths of 3.8 and 0.13 MPa, respectively, and a conductivity of 68.7 S/m. The addition of PDA and PEDOT to the Gel hydrogel endowed the hydrogel with exceptional antioxidant properties to maintain an intracellular redox balance. Additionally, the Gel-PDA/PEDOT hydrogel, which had favorable biocompatibility, significantly increased the migration and proliferation of fibroblasts due to its electroactive properties. A cell migration experiment was performed to assess whether the flexible and electroactive Gel-PDA/PEDOT hydrogel may be a promising wound dressing in skin wound regeneration. These findings provide a strategy for fabricating a multifunctional hydrogel with potential application in bioelectronics and wound dressings.

Alginate/Gauze Incorporated with Hibiscus sabdariffa Linn. Extract as a Bioactive Agent for Wound Dressing Application

In recent years, the development of wound dressings has changed from a passive to an active form by adding antiseptic agents such as polyvinylpyrrolidone (PVPI) and nanoparticles such as silver nanoparticles to facilitate the wound healing process. However, PVPI is toxic to human skin fibroblasts, and silver nanoparticles may result in metal accumulation in the tissues due to their nanosize. Therefore, a new approach to using natural sources from plants such as Hibiscus sabdariffa Linn. (HSL) is promising due to its phytochemical constituents that can serve as a potential therapeutic agent in wound dressings. In this study, freeze-dried alginate/gauze (FDA/gauze) without and with HS extract and calcium alginate/gauze (CA /gauze) with and without HS extract were developed by freeze-drying and gelation, respectively. This study aimed to characterize the properties of alginate/gauze-dressings as wound dressings. The morphology of the designed dressing; FDA/gauze, looks evenly distributed on the surface of the gauze compared to CA/gauze. It was found that FDA/gauze dressings have higher water absorbency than CA /gauze dressings, ranging from 690.43 to 1340.86% from day 1 until day 14. The percentage of water uptake ability increases as the concentration of alginate increases. In addition, the seeded human skin fibroblasts' growth on the alginate/gauze dressings infused with HSL extract growth in clustered, bright, and colourless proves that the cells were viable. Thus, the addition of HSL extract shows to support the process of cell viability.

Lignin-facilitated growth of Ag/CuNPs on surface-activated polyacryloamidoxime nanofibers for superior antibacterial activity with improved biocompatibility

IntroductionNanofibers are one of the role-playing innovations of nanotechnology. Their high surface-to-volume ratio allows them to be actively functionalized with a wide range of materials for a variety of applications. The functionalization of nanofibers with different metal nanoparticles (NPs) has been studied widely to fabricate antibacterial substrates to battle antibiotic-resistant bacteria. However, metal NPs show cytotoxicity to living cells, thereby restricting their application in biomedicine. ObjectivesTo minimize the cytotoxicity of NPs, biomacromolecule lignin was employed as both a reducing and capping agent to green synthesize silver (Ag) and copper (Cu) NPs on the surface of highly activated polyacryloamidoxime nanofibers. The activation of polyacrylonitrile (PAN) nanofibers via amidoximation was employed for enhanced loading of NPs to achieve superior antibacterial activity. MethodologyAt first, electrospun PAN nanofibers (PANNM) were activated to produce polyacryloamidoxime nanofibers (AO-PANNM) by immersing PANNM in a solution of Hydroxylamine hydrochloride (HH) and Na2CO3 under controlled conditions. Later, Ag and Cu ions were loaded by immersing AO-PANNM in different molar concentrations of AgNO3 and CuSO4 solutions in a stepwise manner. The reduction of Ag and Cu ions into NPs to fabricate bimetal-coated PANNM (BM-PANNM) was carried out via alkali lignin at 37 °C for 3 h in a shaking incubator with ultrasonication every 1 h. ResultsAO-APNNM and BM-PANNM hold their nano-morphology except for some changes in fiber orientation. XRD analysis demonstrated the formation of Ag and CuNPs as evident from their respective spectral band. Maximum 8.46 ± 0.14 wt% and 0.98 ± 0.04 wt% Ag and Cu species were loaded on AO-PANNM, respectively as revealed by ICP spectrometric analysis. The hydrophobic PANNM turned into super hydrophilic, having WCA of 14 ± 3.32° after amidoximation which further reduced to 0° for BM-PANNM. However, the swelling ratio of PANNM reduced from 13.19 ± 0.18 g/g to 3.72 ± 0.20 g/g for AO-PANNM. Even at the third cycle test against S. aureus strains, 0.1Ag/Cu-PANNM, 0.3Ag/Cu-PANNM, and 0.5Ag/Cu-PANNM displayed bacterial reduction of 71.3 ± 1.64 %, 75.2 ± 1.91 %, and 77.24 ± 1.25 %, respectively. On 3rd cycle test against E. coli, above 82 % bacterial reduction was noticed for all BM-PANNM. Amidoximation increased COS-7 cell viability up to 82 %. The cell viability of 0.1Ag/Cu-PANNM, 0.3Ag/Cu-PANNM, and 0.5Ag/Cu-PANNM was found to be ∼68 %, ∼62, and 54 %, respectively. In LDH assay, almost no release of LDH was detected, suggesting the compatibility of the cell membrane in contact with BM-PANNM. The improved biocompatibility of BM-PANNM even at higher loading (%) of NPs must be ascribed to the controlled release of metal species in the early stage, antioxidant, and biocompatible lignin capping of NPs. ConclusionsBM-PANNM displayed superior antibacterial activity against E. coli and S. aureus bacterial strains and acceptable biocompatibility of COS-7 cells even at higher loading (%) of Ag/CuNPs. Our findings suggest that BM-PANNM can be used as a potential antibacterial wound dressing and other antibacterial applications where sustained antibacterial activity is needed.

Antimicrobial and Mechanical Properties of Ag@Ti3C2Tx-Modified PVA Composite Hydrogels Enhanced with Quaternary Ammonium Chitosan.

Polyvinyl alcohol (PVA) is a polymeric material with good biocompatibility, excellent hydrophilicity, and a large number of hydroxyl groups. However, due to its insufficient mechanical properties and poor inhibition of bacteria, it has a lack of applications in wound dressings, stent materials, and other fields. In this study, a simple method was used to prepare composite gel materials: Ag@MXene-HACC-PVA hydrogels with a double-network structure were prepared using an acetal reaction. Due to the double cross-linked interaction, the hydrogel has good mechanical properties and is resistant to swelling. The adhesion and bacterial inhibition were enhanced due to the addition of HACC. In addition, the strain sensing properties of this conductive hydrogel were stable, and the GF (specification factor) was 1.7617 at 40-90% strain. Therefore, the dual-network hydrogel with excellent sensing properties, adhesion properties, antibacterial properties, and cytocompatibility has potential applications in biomedical materials, especially as a tissue engineering repair material.

Novel approach to increase chemosensing ability of fluorophore via cross-linked hydrogel film formation

2,5-Bis(4-hydroxy-3-methoxyphenyl)thiazolo[5,4-d]thiazole (MPhTT) fluorophore as a donor–acceptor-donor (D-A-D) type sensor molecule is synthesized for further investigation of sensing ability of the molecule towards various anions and cations. The MPhTT molecule with strong photoluminescence (PL) has been determined to be sensitive against anions with an effective deprotonation mechanism. MPhTT molecule has been demonstrated to have a limited ability to recognize anions by PL response in the solution while selectively sensitive against CN− anion after being embedded into filter paper. Moreover, metal cations detection in the solution is impossible with the MPhTT fluorophore. The use of MPhTT dye as a cross-linker to prepare highly emissive PVA hydrogel films resulted in a reusable chemosensor for acid, base, CN− anion, and metal cations. The mechanical properties of the films and their swelling behavior have also been investigated to show their water-responsive mechanical properties and water intake ability for possible biomedical applications.These findings indicate that increasing the chemosensing ability of the dye by cross-linking of polymers can be used for many fluorophores as an innovative approach. The films with extended mechanical properties can be used for wound dressing, biosensors, moisture sensors, and many other applications.

Development of Biocellulose Sheet Incorporating Aloe vera Gel Extract for Diabetic Wound Healing.

In this study, a biocellulose (BC) sheet containing Aloe vera gel extract (AE) was developed for application in healing chronic wounds, such as diabetic wounds. The BC sheet was produced by Acetobacter xylinum and then lyophilized to obtain dried sheets. A. vera gel was extracted by precipitation in 35% ammonium sulfate, lyophilized, dried, and incorporated into the BC sheet. The protein content of the AE was 12.32 ± 3.4% w/w, with a molecular weight of ∼20 kDa. The release of TNF-α from lipopolysaccharide-induced RAW264.7 cells was reduced by treatment with AE in a dose-dependent manner. The physicochemical and biological properties of the developed sheet were investigated. Morphological examination of the BC/AE sheet using scanning electron microscopy revealed the 3D construction of nanofibrils, which showed high porosity. The BC/AE sheet exhibited water absorption at 74%, and the release of proteins in the AE reached 97.23% at 4 h. The BC sheet incorporated with proteins in the AE at 283.78 ± 7.7 μg/cm2 can promote the wound healing in streptozotocin-induced diabetic rats. The recovering skin in diabetic wounds treated with the BC/AE sheet exhibited a normal cell arrangement without fibrosis, as revealed by histological staining. The research findings indicate that the BC/AE sheet has potential for applications in wound dressings.

Novel Studies in the Designs of Natural, Synthetic, and Compound Hydrogels with Biomedical Applications

Hydrogels are gaining widespread popularity in the biomedical field due to their extraordinary properties, such as biocompatibility, biodegradability, zero toxicity, easy processing, and similarity to physiological tissue. They have applications in controlled drug release, wound dressing, tissue engineering, and regenerative medicine. Among these applications, hydrogels as a controlled drug delivery system stands out, which releases active substances in precise amounts and at specific times. To explore the latest advances in the design of hydrogels, a literature review of articles published in indexed scientific journals, in Scopus and Science Direct, was carried out. This review aimed to discover and describe the most innovative hydrogel research with applications in the biomedical field; hydrogels synthesized with polymers of different origins were selected, such as; i. Natural (dextran, agarose, chitosan, etc.); ii. Synthetic (polyacrylamide, polyethylene glycol, polyvinyl alcohol, etc.); iii. Composites (interpenetrants, hybrid crosslinkers, nanocomposites, etc.). Comparative analysis revealed that hydrogels with composite materials show the most promise. These composite hydrogels combine the advantages of different polymers or incorporate additional components, offering enhanced properties and functionalities. In summary, hydrogels are versatile biomaterials with immense potential in biomedicine. Their unique properties make them suitable for diverse applications. However, innovative designs and formulations must continue to be explored to further advance the capabilities of hydrogels and expand their biomedical applications.

Effect of Royal Gel addition to chitosan matrix for wound dress applications: Fabrication, characterization and artificial neural network analysis

In recent years, traditional and natural medicine products like royal gel (RG) can accelerate the healing of skin wounds. RG was used as an antibacterial material to improve the properties of biocompatible polymers like chitosan and alginate. In this research, RG polymer was added to the chitosan matrix for wound dress application using the freeze-drying technique. Mechanical and biological tests were evaluated to check the wound dressing properties of chitosan with 5 wt% RG. Then, X-ray diffraction (XRD), and scanning electron microscope (SEM) analysis were used to study the phase and morphology of the wound dressing. The sample with 5% RG has better mechanical and chemical properties than pure chitosan wound dressing. In general, the mechanical and physical properties of RG show an increase in elastic modulus from 32 MPa to 62 MPa. Moreover, an increase was observed for the tensile modulus from 1.4 MPa to 3.9 MPa. Although the porosity of wound dressings increased from 76% to 85% by adding 5 wt% RG to chitosan. For the first time, prepared chitosan-RG (5 wt%) was widely used for wound dressing applications.

Synthesis, characterization and potential applications for oxidized agarose

The knowledge of agarose (AG) oxidation using periodate as oxidizer has not been systematically explored. This paper synthesized oxidized agarose (OAG) using solid-sate and solution reaction methods; the reaction mechanism and the properties of OAG samples were systematically evaluated. Chemical structure analysis disclosed that the aldehyde group and carboxyl group contents in all OAG samples are extremely low. Meanwhile, crystallinity, dynamic viscosity and molecular weight of OAG samples is lower than that of the original AG. Reaction temperature, time and sodium periodate dosage are inversely proportional to the decline of the gelling temperature (Tg) and melting temperature (Tm); and the Tg and Tm for the OAG sample obtained are even 19 °C and 22 °C lower than that of the original AG. The as-synthesized OAG samples all possess excellent cytocompatibility and blood compatibility; and can promote the proliferation and migration of fibroblast cells. Last but not least, the gel strength, hardness, cohesiveness, springiness and chewiness of the OAG gel can be effectively regulated via oxidation reaction. In conclusions, both solid and solution oxidation can regulate the physical properties of OAG and enlarge its potential applications in wound dressing, tissue engineering and food areas.

Stimulus-responsive starch-based nanocapsules for targeted delivery and antibacterial applications

Polysaccharide materials have attracted a widespread interest in the biomedical materials field due to their non-toxic, biocompatible and biodegradable properties. In this research, starch was modified with chloroacetic acid, folic acid (FA) and thioglycolic acid and then starch-based nanocapsules loaded with curcumin (FA-RSNCs@CUR) were prepared by the convenient oxidation method. The nanocapsules were prepared with stable particle size distribution of 100 nm. In the drug release test simulating the tumor microenvironment in vitro, the cumulative CUR release rate at 12 h was 85.18 %. Due to FA and FA receptor mediation, it only took 4 h for FA-RSNCs@CUR to achieve internalization by HeLa cells. In addition, cytotoxicity confirmed that starch-based nanocapsules have good biocompatibility as well as protection of normal cells in vitro. And FA-RSNCs@CUR showed certain antibacterial properties in vitro. Therefore, FA-RSNCs@CUR has good potential for future applications in food preservation and wound dressing, and so on.

Tissue Adhesive, Biocompatible, Antioxidant, and Antibacterial Hydrogels Based on Tannic Acid and Fungal-Derived Carboxymethyl Chitosan for Wound-Dressing Applications.

This study aimed to develop hydrogels for tissue adhesion that are biocompatible, antioxidant, and antibacterial. We achieved this by using tannic acid (TA) and fungal-derived carboxymethyl chitosan (FCMCS) incorporated in a polyacrylamide (PAM) network using free-radical polymerization. The concentration of TA greatly influenced the physicochemical and biological properties of the hydrogels. Scanning electron microscopy showed that the nanoporous structure of the FCMCS hydrogel was retained with the addition of TA, resulting in a nanoporous surface structure. Equilibrium-swelling experiments revealed that increasing the concentration of TA significantly improved water uptake capacity. Antioxidant radical-scavenging assays and porcine skin adhesion tests confirmed the excellent adhesive properties of the hydrogels, with adhesion strengths of up to 39.8 ± 1.2 kPa for 1.0TA-FCMCS due to the presence of abundant phenolic groups on TA. The hydrogels were also found to be biocompatible with skin fibroblast cells. Furthermore, the presence of TA significantly enhanced the antibacterial properties of the hydrogels against both Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria. Therefore, the developed drug-free antibacterial and tissue-adhesive hydrogels can potentially be used as wound dressings for infected wounds.

Blend of Multi-Walled Carbon Nanotubes and Quercetin Improves Physicochemical Properties of Chitosan Membrane for Wound Dressing Application

Although wound dressings are essential to protect wound from infection, these wound care products have limited function in facilitating wound healing. This study aimed to synthesize multi-walled carbon nanotube (MWCNT)/quercetin (QUE)/chitosan (CS) blended composite membrane and analyze their physicochemical properties for wound dressing application in comparison to the pure chitosan (CS) membrane. The MWCNT/QUE/CS blended membranes were prepared by mixing CS, QUE and MWCNT at a ratio of 3:1:1 using a solvent casting method. The membranes were analyzed physicochemically for their surface morphology, elemental composition, structural composition, wettability, water vapor transmission rate (WVTR) and swelling properties and were compared to the pure CS membrane. The findings pointed out that the blend of MWCNTs and QUE in the CS matrix produces a membrane with uneven and more hydrophilic surface with water contact angle of 64.70°± 3.7 and low WVTR of 16.26 g/m2.day after 24 h. The swelling analysis showed that the blended membrane was able to absorb more than 60% of water within 10 minutes, although lower than the pure CS membrane. This study revealed that MWCNT/QUE/CS blended membrane could possibly be used as a wound dressing as it may promote moist environment needed for wound healing in addition to its antibacterial and antioxidant properties that may accelerate wound healing process.