Wound Dressing Applications Research Articles

Evaluation of Far‐Field Electrospun Polyvinyl Alcohol/Hyaluronic Acid Nanofibrous Membranes for Skin Tissue Engineering Applications

AbstractElectrospinning has emerged as one of the major technologies for designing and fabricating tissue engineering membranes. The resemblance of the electrospun fiber structure to blood capillaries endowed them with unique capabilities to mimic the native tissue biological characteristics, while the high surface‐to‐volume ratio enables them to exert a controlled release of drug directly to the exposed interstitial tissue. This research attempts to compare the characteristics of different electrospun polyvinyl alcohol/hyaluronic acid (PVA/HA) composite material nanofibrous membranes in order to identify the optimal material‐fabrication combination for wound dressing and skin tissue engineering applications. Far‐field electrospinning equipped with both rotatory and wire collectors is considered for membrane fabrication. PVA with different concentrations and molecular weights of HA are electrospun as nanofibrous membranes considering a voltage of 30 kV on both types of collectors. Comprehensive characterization is conducted including morphological, chemical, thermal, mechanical, and in vitro mucoadhesion analysis. In vitro cell viability/proliferation studies are also carried out and pointed out that the designed membranes are cytocompatible, and able to support keratinocytes proliferation. All these results proved that the fabricated PVA/HA nanofibrous membranes are suitable for wound dressing and skin tissue engineering applications, the optimal material‐fabrication combination is also determined.

Loading of cinnamon essential oil into electrospun octenylsuccinylated starch-pullulan nanofiber mats: Electrospinnability evaluation, structural characterization, and antibacterial potential

The application of cinnamaldehyde essential oil (CEO), which is naturally antibacterial, has been limited due to its high volatility and insolubility in water. This issue may be addressed by nanoencapsulation through electrospinning. In this study, octenylsuccinylated starch (OSS) with different molecular structures blended with pullulan (PUL) was developed to load CEO for enhanced antibacterial potential. OSS with a smaller molecular size and a higher degree of substitution is beneficial for the electrospinning of OSS/PUL into high-quality nanofiber mats. The electrospinning process of OSS/PUL aqueous dopes is mainly influenced by moderate apparent viscosity, increased conductivity, and reduced surface tension. CEO loading through physical adsorption significantly changed the fiber microstructure and displayed antibacterial effects against Staphylococcus aureus, Escherichia coli, and Aspergillus flavus for electrospun OSS/PUL nanofiber mats. This study demonstrates that electrospun starch-based nanofiber mats with loading of essential oils could hold a potential application in active food packaging and wound dressing.

Bacterial Cellulose Applied in Wound Dressing Materials: Production and Functional Modification - A Review.

In recent years, the development of new type wound dressings has gradually attracted more attention. Bacterial cellulose (BC) is a natural polymer material with various unique properties, such as ultrafine 3D nanonetwork structure, high water retention capacity, and biocompatibility. These properties allow BC to be used independently or in combination with different components (such as biopolymers and nanoparticles) to achieve diverse effects. This means that BC has great potential as a wound dressing. However, systematic summaries for the production and commercial application of BC-based wound dressings are still lacking. Therefore, this review provides a detailed introduction to the production fermentation process of BC, including various production strains and their biosynthetic mechanisms. Subsequently, with regard to the functional deficiencies of bacterial cellulose as a wound dressing, recent research progress in this area is enumerated. Finally, prospects are discussed for the low-cost production and high-value-added product development of BC-based wound dressings.

Preparation and properties of a multi-crosslinked chitosan/sodium alginate composite hydrogel

Wound dressings play an important role in promoting wound healing, and hydrogels with high water content, biocompatibility, and elasticity have broad application in wound dressings. In this study, we have successfully prepared chitosan/sodium alginate /tannic acid (CST) composite hydrogels by dissolving and mixing chitosan/sodium alginate with alkali/urea/water solution and cross-linking multiple times with epichlorohydrin, calcium chloride and tannic acid in turn. The results showed that the CST-31 prepared with a mass ratio of chitosan to sodium alginate at 3:1 had appropriate mechanical properties, high porosity and water retentivity, good biocompatibility and strong antibacterial activity, and could rapidly promote wound healing in mice. In conclusion, CST-31 has an important application prospect as a wound dressing.

Nanosilver Embedded in a Magnetosome Nanoflower to Enhance Antibacterial Activity for Wound Dressing Applications.

The natural biofilm on magnetosomes obtained from the biomineralization of magnetotactic bacteria, which replaced a complex chemical modification process on the surface of Fe3O4, can be used as the organic component and copper(II) ions as the inorganic component to form organic-inorganic nanoflowers in phosphate systems. Characterization by scanning electron microscopy, Fourier transform infrared spectroscopy, and vibrating-sample magnetometry proved that magnetic nanoflowers loaded with silver ions (Ag/MN-Cu×NFs) were successfully fabricated. In vitro antibacterial experiments demonstrated that Ag/MN-Cu×NFs displayed strong antibacterial effects against Escherichia coli and Staphylococcus aureus, with minimum inhibitory concentrations of 10 and 80 μg/mL, respectively. Ag/MN-Cu×NFs, which possessed good biocompatibility as confirmed by cytotoxicity and hemolysis tests, were able to promote wound healing in the face of bacterial infection in vivo without causing toxicity to major organs. Therefore, magnetosomes as a natural carrier have great application potential in the synthesis of multifunctional magnetosomes by direct hybridization with a target substance.

Temporal Changes in the Skin Microbiome of Epidermolysis Bullosa Patients following the Application of Wound Dressings.

Epidermolysis bullosa (EB) is a group of rare hereditary skin disorders characterized by the formation of painful blisters, erosions, and ulcers. In addition, the wounds can easily become infected with different pathogens. Therefore, the dynamics in the microbial populations across the various stages of EB can shed light on pathophysiology, the effect of treatment, and the factors involved in its recovery, but they are understudied. We thus sought to characterize the skin microbiome among patients with EB over time. A prospective study conducted in the pediatric dermatology clinic at Soroka Medical Center, Beer-Sheva, Israel. Children (0-18) with simplex and recessive dystrophic EB were sampled at two different time points: before a therapeutic regimen and 90 days (±14 days) later. Samples were obtained from lesional skin (wound), healthy, non-lesional skin, and seborrheic skin (forehead). Samples were subject to 16S rRNA amplicon sequencing. Analyses performed included comparisons of relative abundance at the phyla and genera taxonomic levels, alpha and beta diversity comparisons, and differential abundance. 32 children with EB were enrolled, for whom 192 skin microbiome samples were obtained. Lesional skin samples harbored significantly less Bacteroidota and Fusobacteriota before the initiation of treatment. Following topical dressing, we observed more Firmicutes and less Proteobacteria in lesional skin samples than healthy and seborrheic skin samples. In addition, Staphylococcus was significantly more abundant in lesional samples than in non-lesional and seborrheic samples following treatment. Our study recaptured the reduced bacterial diversity and increased staphylococcal carriage in EB patients, showing a potential effect of topical dressing either directly on the wound microbiome or indirectly through the contribution towards skin healing. The detection of Firmicutes in general, and S. aureus specifically, commensurate with the application of a wound dressing may warrant the use of additional treatment methods to facilitate wound healing. Future studies in these patients should prospectively correlate the temporal changes in the microbiome associated with various treatment modalities in order to optimize the care of EB patients.

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.

“Sandwich-like” structure electrostatic spun micro/nanofiber polylactic acid-polyvinyl alcohol-polylactic acid film dressing with metformin hydrochloride and puerarin for enhanced diabetic wound healing

A diabetic wound is a typical chronic wound with a long repair process and poor healing effects. It is an effective way to promote diabetic wound healing to design electrospinning nanofiber films with drug-assisted therapy, good air permeability and, a multilayer functional structure. In this paper, a diabetic wound dressing with a “sandwich-like” structure was designed. Metformin hydrochloride, loaded in the hydrophilic PVA inner layer, could effectively promote diabetic wound healing. The drug release was slowed down by osmosis. The laminate film dressing had good mechanical properties, with tensile strength and elongation at break reaching 5.91 MPa and 90.47 %, respectively, which was close to human skin. The laminate film loaded with erythromycin and puerarin in the hydrophobic PLA outer layer had good antibacterial properties. In addition, due to the high specific surface of the electrostatic spun film, it exhibited high water vapor permeability. It facilitates the gas exchange between the wound and the outside world. The cell experiments proved that the laminate film dressing had good biocompatibility. There was no toxic side effect on cell proliferation. In the diabetic animal wound model, it was shown that the closure rate of diabetic wound repair by laminate film reached 91.11 % in the second week. Our results suggest that the “sandwich-like” nanofiber film dressing could effectively promote the healing process and meet the various requirements of diabetic wound dressing as a promising candidate for future clinical application of chronic wound dressings.

Use of bioelectric dressings for patients with hard-to-heal wounds: a case report.

There are many types of dressings available for the management of hard-to-heal (chronic) wounds. This case report illustrates the efficacy of bioelectric dressings in healing hard-to-heal wounds in five patients. Of the patients, four had diabetic foot ulcers (DFUs) and one had a surgical site infection. Wounds were examined using the TIMES concept and debridement was carried out if needed. Amorphous hydrogel was used as conduction fluid before the application of the bioelectric wound dressings. The wound was covered with foam dressing and crepe bandage. In this case report, among all five wounds, one wound healed completely while the other four reduced in size, with the presence of more granulation and re-epithelialisation. In this case report, bioelectric wound dressings were effective in managing infection and promoting wound healing.

Design of polysaccharide gum based network copolymeric hydrogels for drug delivery and wound dressing applications

This article deals with the exploration of the design of network crosslinked structure by covalent bonding for use as wound dressing materials keeping in view inherent therapeutic role of neem gum in wound healing. These copolymeric hydrogels were prepared by graft-copolymerization reaction of carbopol and poly (N-vinylpyrrolidone) (poly (NVP). Antibiotic drug levofloxacin was encapsulated in dressings for better wound healing. The scanning electron microscopy (SEM), atomic force microscopy (AFM), Fourier transform infrared (FTIR) spectroscopy, 13C nuclear magnetic resonance (NMR) spectroscopy, X-ray diffraction (XRD), thermogravimetric analysis (TGA), differential thermal gravimetry (DTG), and differential scanning calorimetry (DSC) techniques were applied for characterization. NMR and FTIR demonstrated incorporation of carbapol and poly (NVP) in dressings. XRD indicated amorphous state in copolymeric dressings. Interactions of copolymers with drug, blood and bio membrane were studied to evaluate biomedical properties which revealed controlled release of drug from hydrogel dressings which were possessing blood-compatible (haemolytic value ​= ​2.45 ​± ​0.82) and mucoadhesive (detachment force ​= ​124 ​± ​41 ​mN) properties. Dressings were permeable to O2 and H2O vapour and absorbed 6.68 ​± ​0.62 ​g/g wound fluid which is ideal dressing characteristic. Diffusion mechanism type of drug levofloxacin was Fickian with kinetic model First order. These properties suggested use of hydrogel material for wound dressing and drug delivery applications for better wound care management.

A Sustainable, Green-Processed, Ag-Nanoparticle-Incorporated Eggshell-Derived Biomaterial for Wound-Healing Applications.

The eggshell membrane (ESM) is a natural biomaterial with unique physical and mechanical properties that make it a promising candidate for wound-healing applications. However, the ESM's inherent properties can be enhanced through incorporation of silver nanoparticles (AgNPs), which have been shown to have antimicrobial properties. In this study, commercially produced AgNPs and green-processed AgNPs were incorporated into ESM and evaluated for their physical, biological, and antimicrobial properties for potential dermal application. The ESM was extracted using various techniques, and then treated with either commercially produced AgNPs (Sigma-Aldrich, Poole, UK) or green-synthesized AgNPs (Metalchemy, London, UK) to produce AgNPs-ESM samples. The physical characteristics of the samples were evaluated using scanning electron microscopy (SEM), Fourier Transform Infrared (FTIR) spectroscopy, and the biological properties were assessed through in vitro studies using human dermal fibroblasts (HDFs) and BJ cells. The SEM analysis of the AgNPs-ESM samples showed localization of AgNPs on the ESM surface, and that the ESM maintained its structural integrity following AgNP incorporation. The FTIR confirmed loading of AgNPs to ESM samples. The biological studies showed that the 5 μg/mL AgNPs-ESM samples were highly biocompatible with both HDFs and BJ cells, and had good viability and proliferation rates. Additionally, the AgNPs-ESM samples demonstrated pro-angiogenic properties in the CAM assay, indicating their potential for promoting new blood vessel growth. Assessment of the antimicrobial activity of the enhanced AgNPs/ESMs was validated using the International Standard ISO 16869:2008 methodology and exploited Cladosporium, which is one of the most commonly identified fungi in wounds, as the test microorganism (≥5 × 106 cells/mL). The AgNPs-ESM samples displayed promising antimicrobial efficacy as evidenced by the measured zone of inhibition. Notably, the green-synthesized AgNPs demonstrated greater zones of inhibition (~17 times larger) compared to commercially available AgNPs (Sigma-Aldrich). Although both types of AgNP exhibited long-term stability, the Metalchemy-modified samples demonstrated a slightly stronger inhibitory effect. Overall, the AgNPs-ESM samples developed in this study exhibited desirable physical, biological, and antimicrobial properties for potential dermal wound-dressing applications. The use of green-processed AgNPs in the fabrication of the AgNPs-ESM samples highlights the potential for sustainable and environmentally friendly wound-healing therapies. Further research is required to assess the long-term biocompatibility and effectiveness of these biomaterials in vivo.

Preparation of pH-responsive oxidized regenerated cellulose hydrogels compounded with nano-ZnO/chitosan/aminocyclodextrin ibuprofen complex for wound dressing

Recently, using oxidized regenerated cellulose (ORC) to build a hydrogel system on promoting healing in wounds has a fast-growing market. However, it remains a challenge to improve the degree of oxidation of regenerated cellulose (RC) and to prepare matrices that are uniquely responsive to the wound environment. Herein, highly oxidized aldehyde-based cellulose from porous RC was prepared by NaBH4-HCl swelling and then NaIO4 oxidation pathway. Chitosan (CS), ethylenediamine-cyclodextrin (EDA-CD) along with ORC have been used to construct hydrogel matrices that are pH-responsive and capable of controlled drug release for use as future wound dressings. And zinc oxide nanoparticles (ZnO NPs) with antimicrobial effect and ibuprofen (IBU) with analgesic effect were piggybacked into the hydrogel system. XRD was used to study the presence of ZnO. SEM was used to observe the surface structure of the prepared hydrogel. TEM was used to observe the particle size of the ZnO NPs. Meanwhile, the oxidation conditions of the ORC were explored. Furthermore, the mechanical, swelling, water retention, cytotoxicity, bacterial inhibition properties and treatment effect, which are closely related to the application of wound dressing, were carefully researched. The unique characteristics of prepared hydrogel, including pH-responsive degradability and sustained release properties of IBU, were also investigated.

Thymol incorporated gellan gum/carboxymethyl cellulose/hyaluronic acid films for wound dressings applications

Thymol incorporated gellan gum/carboxymethyl cellulose/hyaluronic acid films for wound dressings applications

Silk fibroin/polyvinyl alcohol composite film loaded with antibacterial AgNP/polydopamine-modified montmorillonite; characterization and antibacterial properties

In this study, a kind of nanocomposite film was fabricated via combining silk fibroin, polyvinyl alcohol (SF/PVA) and AgNP/polydopamine-modified Montmorillonite (AgNP/PDA-Mt). The structural characteristics and properties of the SF/PVA/AgNP/PDA-Mt nanocomposites films were identified using X-ray diffraction (XRD), Thermal gravimetric analyzer (TGA), Fourier transform infrared spectroscopy (FTIR), EDS-mapping analyses and Scanning electron microscope (SEM). The results indicated enhanced thermal performance of SF/PVA/AgNP/PDA-Mt nanocomposites with increased AgNP/PDA-Mt weight. The nanocomposite film exhibited excellent antibacterial activity against E. coli and S. aureus. The 2 % SF/PVA/AgNP/PDA-Mt film showed the highest zone of inhibition with an average inhibition circle diameter of 26.1 mm against E. coli and 20.61 mm against S. aureus. Cytotoxicity test results indicated that the nanocomposites films were biocompatible with L929 cells with a 100 % survival rate, which can be considered as one of the advantages of new nanocomposites films. These findings suggest that SF/PVA/AgNP/PDA-Mt films have potential clinical applications in wound dressing and antibacterial biomedical applications.

Polydopamine-Functionalized Bacterial Cellulose as Hydrogel Scaffolds for Skin Tissue Engineering.

Bacterial cellulose (BC) is a natural polysaccharide polymer hydrogel produced sustainably by the strain Gluconacetobacter hansenii under static conditions. Due to their biocompatibility, easy functionalization, and necessary physicochemical and mechanical properties, BC nanocomposites are attracting interest in therapeutic applications. In this study, we functionalized BC hydrogel with polydopamine (PDA) without toxic crosslinkers and used it in skin tissue engineering. The BC nanofibers in the hydrogel had a thickness of 77.8 ± 20.3 nm, and they could be used to produce hydrophilic, adhesive, and cytocompatible composite biomaterials for skin tissue engineering applications using PDA. Characterization techniques, namely Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), and Raman spectroscopy, were performed to investigate the formation of polydopamine on the BC nanofibers. The XRD peaks for BC occur at 2θ = 14.65°, 16.69°, and 22.39°, which correspond to the planes of (100), (010), and (110) of cellulose type Iα. Raman spectroscopy confirmed the formation of PDA, as indicated by the presence of bands corresponding to the vibration of aromatic rings and aliphatic C-C and C-O stretching at 1336 and 1567 cm-1, respectively. FTIR confirmed the presence of peaks corresponding to PDA and BC in the BC/PDA hydrogel scaffolds at 3673, 3348, 2900, and 1052 cm-1, indicating the successful interaction of PDA with BC nanofibers, which was further corroborated by the SEM images. The tensile strength, swelling ratio, degradation, and surface wettability characteristics of the composite BC biomaterials were also investigated. The BC/PDA hydrogels with PDA-functionalized BC nanofibers demonstrated excellent tensile strength and water-wetting ability while maintaining the stability of the BC fibers. The enhanced cytocompatibility of the BC/PDA hydrogels was studied using the PrestoBlue assay. Culturing murine NIH/3T3 fibroblasts on BC/PDA hydrogels showed higher metabolic activity and enhanced proliferation. Additionally, it improved cell viability when using BC/PDA hydrogels. Thus, these BC/PDA composite biomaterials can be used as biocompatible natural alternatives to synthetic substitutes for skin tissue engineering and wound-dressing applications.

Smart shape memory polymers and their significance in biomedical applications: A review

AbstractShape‐memory polymers (SMP) are materials responsive to stimuli, which will be modified to their initial form on the occurrence of an appropriate input. SMPs have been a class of impulsively valuable material in the last few decades. Because of their numerous, adaptable uses across a wide range, “wise” materials (SMPs) have attracted intense interest in the advanced material fields. Besides others, they need a substantial part of the area of the medical field. SMPs provide flexibility for promoting keyhole surgery, which offers stable strength, imposes stabilization forces, rinse therapeutic agents, and are degradable. Basic research on proposed SMP systems for medicine emphasizes biocompatibility, tolerability, disinfection, and non‐toxicity. This article mentions an overview of the latest advancements in the applications of SMP been reported. The article aims to incorporate all the possible applications of SMP, making it a versatile material that juxtaposes it with other advanced materials. The significance of SMP in the biomedical field, drug development, cardio‐vascular diseases, tissue engineering, wound dressing, surgical sutures, and many other applications has been highlighted. Another section dedicated to the antimicrobial abilities of SMP has been discussed. The last section is devoted to the conclusion and future developments in the respective area. Thus, this review focuses on many biomedicine areas and tube, medical science, and neuronic applications regarding the development and ability of SMPs to boost the quality of services in these fields.

Characterization and biological evaluation of new PLGA/fibrin/lignin biocomposite electrospun scaffolds

In this study, we produced electrospun scaffolds from 10% pure PLGA solution, and 10% polyblend solutions of PLGA/Fibrin, PLGA/Lignin, and PLGA/Fibrin/Lignin with proportions of 9:1, 8:2, 7:3, 7:2:1, 6:2:2, and 5:2:3 and characterized them physiochemically and biologically. FTIR and EDX results verified the chemical composition of the fibers. All scaffolds exhibited homogenous nanostructures with fiber diameters ranging from 0.1 to 2.5 μm and the highest average fiber diameter belonged to PLGA/Lignin fibers. Increasing the lignin proportion led to a decrease in fibers diameter and a change in color to brown. Fibrin improved the hydrophobicity of the scaffolds, and the incorporation of fibrin, lignin, or fibrin/lignin improved the absorption capacity of the scaffolds (up to 91.7%). From day 45 onwards, fibrin-containing scaffolds started to degrade much faster. By day 90, PLGA/20%Fibrin/30%Lignin showed the highest degradation ratio of 82%, while PLGA/10%Lignin showed the lowest at 51.4%. All scaffolds exhibited high porosity percentage (over 78%), with porosity enhanced by increasing fibrin and decreasing lignin. The pure PLGA scaffold and PLGA/10%Lignin showed the highest stiffness and tensile strength, respectively. The addition of natural components gradually decreased the scaffolds’ tensile strength and fracture strain. MTT results showed higher absorbance reading at 490 nm for PLGA, PLGA/10%Fibrin, and all three PLGA/Lignin scaffolds from day 3 to day 7. On day 7, PLGA/10%Fibrin exhibited the highest cell viability, followed by PLGA/10%Lignin and PLGA/20%Fibrin/10%Lignin. SEM micrographs revealed the presence of h-ADSCs with spindle-like morphologies, attached and proliferated well on all scaffolds. PLGA/10%Fibrin, PLGA/10%Lignin, and PLGA/20%Fibrin/10%Lignin were selected as the preferred options from each set of scaffolds. Among them, PLGA/20%Fibrin/10%Lignin exhibited superior physical features and actively enhanced the biological responses of the cells due to its physio-mechanical signals and the advanced features of lignin, making it suitable for tissue engineering, wound dressing, drug delivery, and other biomedical applications.

Investigation through the antimicrobial activity of electrospun PCL nanofiber mats with green synthesized Ag–Fe nanoparticles

Wound or device infections with drug resistant microorganisms are a major challenge in medicine that could increase morbidity and mortality rate, with a great financial burden on the health care system. Nanofibers with antimicrobial coating have been widely applied in wound dressing and tissue engineering to decrease the risk of infections. In the present study, Ag–Fe core-shell NPs were green synthesized by applying Ducrosia anethifolia plant extracted as a stabilizing and reducing agent. The novel nanocomposites by a combination of Ag–Fe and polymeric polycaprolactone (PCL) nanofibers were produced. Synthesized nanoparticles and nanocomposites were characterized using several physical and mechanical techniques, including scanning electron microscopy (SEM), dynamic light scattering method (DLS), X-ray diffraction (XRD), transmission electron microscopy (TEM), fourier transform infrared (FT-IR) spectroscopy, ultraviolet–visible absorption spectroscopy (UV–vis), and tensile test. The mean size of the synthesized Ag and Ag–Fe core-shell nanoparticles were 4.1 and 18.4 nm. Silver nanoparticles were successfully coated with Fe shell and nearly spherical core-shell shape. SEM images showed that PCL nanofibers have an average size of 265 nm. The results revealed that the increase in the Ag–Fe core-shell NPs' concentration leads to the smaller size of nanofibers. The antimicrobial properties of Ag–Fe core-shell and PCL/Ag–Fe nanocomposites were evaluated against some clinically important bacteria and fungi. Also, the cytotoxicity of PCL/Ag–Fe nanocomposites on fibroblast cells Natural man (NHDF) was assessed for 24, 48, and 72 h. The results of the study confirmed minimal cellular toxicity and considerable antimicrobial properties of green synthesized PCL/Ag–Fe nanocomposites, especially against some drug resistant pathogens, which could be promising new insight to improve the PCL-based composites applications in wound dressings or medical devices.

Polyacrylic Acid Hydrogel Coating for Underwater Adhesion: Preparation and Characterization.

Underwater adhesion involves bonding substrates in aqueous environments or wet surfaces, with applications in wound dressing, underwater repairs, and underwater soft robotics. In this study, we investigate the underwater adhesion properties of a polyacrylic acid hydrogel coated substrate. The underwater adhesion is facilitated through hydrogen bonds formed at the interface. Our experimental results, obtained through probe-pull tests, demonstrate that the underwater adhesion is rapid and remains unaffected by contact pressure and pH levels ranging from 2.5 to 7.0. However, it shows a slight increase with a larger adhesion area. Additionally, we simulate the debonding process and observe that the high-stress region originates from the outermost bonding region and propagates towards the center, spanning the thickness of the target substrate. Furthermore, we showcase the potential of using the underwater adhesive hydrogel coating to achieve in-situ underwater bonding between a flexible electronic demonstration device and a hydrogel contact lens. This work highlights the advantages of employing hydrogel coatings in underwater adhesion applications and serves as inspiration for the advancement of underwater adhesive hydrogel coatings capable of interacting with a wide range of substrates through diverse chemical and physical interactions at the interface.

Sustainable functionalized chitosan based nano-composites for wound dressings applications: A review

Functionalized chitosan nanocomposites have been studied for wound dressing applications due to their excellent antibacterial and anti-fungal properties. Polysaccharides show excellent antibacterial and drug-release properties and can be utilized for wound healing. In this article, we comprise distinct approaches for chitosan functionalization, such as photosensitizers, dendrimers, graft copolymerization, quaternization, acylation, carboxyalkylation, phosphorylation, sulfation, and thiolation. The current review article has also discussed brief insights on chitosan nanoparticle processing for biomedical applications, including wound dressings. The chitosan nanoparticle preparation technologies have been discussed, focusing on wound dressings owing to their targeted and controlled drug release behavior. The future directions of chitosan research include; a) finding an effective solution for chronic wounds, which are unable to heal completely; b) providing effective wound healing solutions for diabetic wounds and venous leg ulcers; c) to better understanding the wound healing mechanism with such materials which can help provide the optimum solution for wound dressing; d) to provide an improved treatment option for wound healing.