Antibacterial biohybrid nanofibers for wound dressings

Copper-thiosemicarbazone complexes conjugated-cellulose fibers: Biodegradable materials with antibacterial capacity

Personal protective equipment (PPE) is vital in battling bacteria crisis, but conventional PPE materials lack antimicrobial activities and environmental friendliness. Our work focused on developing biodegradable and antibacterial fibers as promising bioprotective materials. Here, we grafted highly effective antibacterial copper-thiosemicarbazone complexes (CT1-4) on cellulose fibers via covalent linkages. Multiple methods were used to characterize the chemical composition or morphology of CT1-4 conjugated-fibers. Conjugation of CT1-4 maintains the mechanical properties (Breaking strength: 2.35-2.45 cN/dtex, Breaking elongation: 7.19 %-7.42 %) and thermal stability of fibers. CT1 can endow cellulose fibers with the excellent growth inhibition towards Escherichia coli (E. coli) (GIR: 61.5 % ± 1.28 %), Staphylococcus aureus (S. aureus) (GIR: 85.7 % ± 1.93 %), and Bacillus subtilis (B. subtilis) (GIR: 87.6 % ± 1.44 %). We believe that the application of CT1 conjugated-cellulose fibers is not limited to the high-performance PPE, and also can be extended to various types of protective equipment for food and medicine safety.

Comparison of physical, mechanical and biological effects of leucocyte-PRF and advanced-PRF on polyacrylamide nanofiber wound dressings: In vitro and in vivo evaluations

Platelet-rich fibrin (PRF) is extracted from the blood without biochemical interference and, also, with the ability of a long-term release of growth factors that can stimulate tissue repair and regerenation. Here, leucocyte- and platelet-rich fibrin (L-PRF) and advanced platelet-rich fibrin (A-PRF) were extracted and utilized for the creation of nanofibers containing polyacrylamide (PAAm), PAAm / L-PRF and PAAm / A-PRP through electrospinning processing technique. The effect of the type of PRF on the physical, mechanical and biological properties of the resultant nanofiberous wound dressings are thoroughly evaluated. The results presented in the current study reveals that the fiber diameter is grealtly reduced through the utilization of L-PRF. In addition, mechanical property is also positively affected by L-PRF and the degradation rate is found to be higher compared to A-PRF group. The L929 cells proliferation and adhesion, angiogenesis potential and wound healing ability was significantly higher in PAAm/A-PRF nanofibers compared to pure PAAm and PAAm/L-PRF nanofibers owed to the release of vascular endothelial growth factor (VEGF) and platelet derived growth factor (PDGF). Overall, the utilization of L-PRF or A-PRF can improve the physical, mechanical and biological behavior of nanofiber making them an ideal candidate for wound dressings, with the emphasis on the skin tissue repair and regeneration applications.

Bioactive glass-based fibrous wound dressings

Since the discovery of silicate bioactive glass (BG) by Larry Hench in 1969, different classes of BGs have been researched over decades mainly for bone regeneration. More recently, validating the beneficial influence of BGs with tailored compositions on angiogenesis, immunogenicity and bacterial infection, the applicability of BGs has been extended to soft tissue repair and wound healing. Particularly, fibrous wound dressings comprising BG particle reinforced polymer nanofibers and cotton-candy-like BG fibers have been proven to be successful for wound healing applications. Such fibrous dressing materials imitate the physical structure of skin's extracellular matrix and release biologically active ions e.g. regenerative, pro-angiogenic and antibacterial ions, e.g. borate, copper, zinc, etc., that can provoke cellular activities to regenerate the lost skin tissue and to induce new vessels formation, while keeping an anti-infection environment. In the current review, we discuss different BG fibrous materials meant for wound healing applications and cover the relevant literature in the past decade. The production methods for BG-containing fibers are explained and as fibrous wound dressing materials, their wound healing and bactericidal mechanisms, depending on the ions they release, are discussed. The present gaps in this research area are highlighted and new strategies to address them are suggested.

Hybrid-Based Wound Dressings: Combination of Synthetic and Biopolymers

Most commercialized wound dressings are polymer-based. Synthetic and natural polymers have been utilized widely for the development of wound dressings. However, the use of natural polymers is limited by their poor mechanical properties, resulting in their combination with synthetic polymers and other materials to enhance their mechanical properties. Natural polymers are mostly affordable, biocompatible, and biodegradable with promising antimicrobial activity. They have been further tailored into unique hybrid wound dressings when combined with synthetic polymers and selected biomaterials. Some important features required in an ideal wound dressing include the capability to prevent bacteria invasion, reduce odor, absorb exudates, be comfortable, facilitate easy application and removal as well as frequent changing, prevent further skin tear and irritation when applied or removed, and provide a moist environment and soothing effect, be permeable to gases, etc. The efficacy of polymers in the design of wound dressings cannot be overemphasized. This review article reports the efficacy of wound dressings prepared from a combination of synthetic and natural polymers.

Combination of natural polyanions and polycations based on interfacial complexation for multi-functionalization of wound dressings

Multi-functionalization of wound dressings with natural polymers is meaningful and remains a challenge. The combination of natural polyanions and polycations appears to be a promising strategy. Still, its performances based on current layer-by-layer self-assembly or homogeneous complexation are mutable and limited. Herein, Ca2+-incorporated carboxymethyl cellulose (Ca/Na-CMC) and hydroxypropyltrimethyl ammonium chloride chitosan (HACC) are adopted as the model polyanion and polycation, respectively, to develop multi-functionalized dressings based on interfacial complexation. The dressings exhibit a multilayer structure composed of a polyanion layer (Ca/Na-CMC) for hemostasis and promotion of cell proliferation, a formed polyelectrolyte complex (PEC) layer for structural stability, and a polycation layer (HACC) for antibiosis. Compared to the dressing based on homogeneous complexation, the multilayer dressings show stronger moisture penetrability (around 1,150 g/m2/24 h), higher hemostatic activity, and higher antibacterial rate (up to 100%) and promoted effect on cell proliferation. An in vivo evaluation using a rat full-thickness skin defect model reveals that the multilayer dressings can accelerate wound healing in 2 weeks. Overall, owing to interfacial complexation resulting in separate layers, the performances of polyanions and polycations after combination are more predictable, and their biological functions can be effectively preserved. These findings not only support the extensive application of multilayer dressings but also offer an alternative strategy for multi-functionalizing wound dressings with natural polyanions and polycations.

Manufacturing of Zinc Oxide Nanoparticle (ZnO NP)-Loaded Polyvinyl Alcohol (PVA) Nanostructured Mats Using Ginger Extract for Tissue Engineering Applications

In this research, as an alternative to chemical and physical methods, environmentally and cost-effective antimicrobial zinc oxide nanoparticles (ZnO NP) were produced by the green synthesis method. The current study focuses on the production of ZnO NP starting from adequate precursor and Zingiber officinale aqueous root extracts (ginger). The produced ZnO NP was loaded into electrospun nanofibers at different concentrations for various tissue engineering applications such as wound dressings. The produced ZnO NPs and ZnO NP-loaded nanofibers were examined by Scanning Electron Microscopy (SEM) for morphological assessments and Fourier-transform infrared spectrum (FT-IR) for chemical assessments. The disc diffusion method was used to test the antimicrobial activity of ZnO NP and ZnO NP-loaded nanofibers against three representatives strains, Escherichia coli (Gram-negative bacteria), Staphylococcus aureus (Gram-positive bacteria), and Candida albicans (fungi) microorganisms. The strength and stretching of the produced fibers were assessed using tensile tests. Since water absorption and weight loss behaviors are very important in tissue engineering applications, swelling and degradation analyses were applied to the produced nanofibers. Finally, the MTT test was applied to analyze biocompatibility. According to the findings, ZnO NP-loaded nanofibers were successfully synthesized using a green precipitation approach and can be employed in tissue engineering applications such as wound dressing.

"Jianbing" styling multifunctional electrospinning composite membranes for wound healing

Wound infection and excessive exudate can affect the process of wound healing. However, the disadvantage of the anti-microbial wound dressings is that the biological fluids are ineffectively removed. Inspired by making "Chinese Jianbing", a composite wound nano-dressing was developed consisting of a hydrophilic outer layer (chitosan&polyvinyl alcohol: CTS-PVA) and a hydrophobic inner layer (propolis&polycaprolactone: PRO-PCL) by combining casting and electrospinning methods for effective antibacterial and unidirectional removing excess biofluids. In vitro, the composite wound nano-dressing of PRO-PCL and CTS-PVA (PPCP) could strongly inhibit Pseudomonas aeruginosa. Furthermore, PPCP wound dressing had excellent antioxidant properties and blood coagulation index for effective hemostatic. Importantly, it had a preferable water absorption for removing excess biofluid. In vivo, it had anti-inflammatory properties and promoted collagen Ⅰ preparation, which realized 80% wound healing on day 7. In short, the PPCP wound dressing provides a new direction and option for antibacterial and removes excess biofluid.

Vanillin enhances the antibacterial and antioxidant properties of polyvinyl alcohol-chitosan hydrogel dressings

Wound management requires the preparation of controllable, safe and effective dressings to isolate the wound from the external environment. Currently, widely used commercial dressings focus on the isolation effect rather than an environment conducive to wound healing. To provide the dressing with beneficial properties such as wetting and antioxidant and antibacterial activity, this study used polyvinyl alcohol (PVA) hydrogel as the base material and introduced chitosan (CS) and vanillin (V) to design a PVA/CS/V three-phase hydrogel dressing. The dressings were prepared using a freeze-thaw cycle to achieve properties. We conducted a comparative analysis of PVA/V and PVA/CS two-phase hydrogels. The PVA/CS/V (PCV) hydrogel dressing maintaining an elastic modulus at >5 kPa at 15-40 °C. An in vitro antibacterial assay showed the potent antibacterial ability of hydrogels against gram-positive and -negative bacteria, and cells in some PCV groups showed higher activity. The antioxidant results showed that PCV hydrogel had a potent scavenging effect on DPPH, ABTS⁺, and PTIO free radical. The antibacterial and antioxidant properties of three-phase hydrogel showed the best performance in all experimental groups. These results suggest that PCV hydrogel has value in commercial applications due to its simple preparation process and excellent biological properties.

Inflammation-mediated matrix remodeling of extracellular matrix-mimicking biomaterials in tissue engineering and regenerative medicine

Extracellular matrix (ECM)-mimicking biomaterials are considered effective tissue-engineered scaffolds for regenerative medicine because of their biocompatibility, biodegradability, and bioactivity. ECM-mimicking biomaterials preserve natural microstructures and matrix-related bioactive components and undergo continuous matrix remodeling upon transplantation. The interaction between host immune cells and transplanted ECM-mimicking biomaterials has attracted considerable attention in recent years. Transplantation of biomaterials may initiate injuries and early pro-inflammation reactions characterized by infiltration of neutrophils and M1 macrophages. Pro-inflammation reactions may lead to degradation of the transplanted biomaterial and drive the matrix into a fetal-like state. ECM degradation leads to the release of matrix-related bioactive components that act as signals for cell migration, proliferation, and differentiation. In late stages, pro-inflammatory cells fade away, and anti-inflammatory cells emerge, which involves macrophage polarization to the M2 phenotype and leukocyte activation to T helper 2 (Th2) cells. These anti-inflammatory cells interact with each other to facilitate matrix deposition and tissue reconstruction. Deposited ECM molecules serve as vital components of the mature tissue and influence tissue homeostasis. However, dysregulation of matrix remodeling results in several pathological conditions, such as aggressive inflammation, difficult healing, and non-functional fibrosis. In this review, we summarize the characteristics of inflammatory responses in matrix remodeling after transplantation of ECM-mimicking biomaterials. Additionally, we discuss the intrinsic linkages between matrix remodeling and tissue regeneration. STATEMENT OF SIGNIFICANCE: Extracellular matrix (ECM)-mimicking biomaterials are effectively used as scaffolds in tissue engineering and regenerative medicine. However, dysregulation of matrix remodeling can cause various pathological conditions. Here, the review describes the characteristics of inflammatory responses in matrix remodeling after transplantation of ECM-mimicking biomaterials. Additionally, we discuss the intrinsic linkages between matrix remodeling and tissue regeneration. We believe that understanding host immune responses to matrix remodeling of transplanted biomaterials is important for directing effective tissue regeneration of ECM-mimicking biomaterials. Considering the close relationship between immune response and matrix remodeling results, we highlight the need for studies of the effects of clinical characteristics on matrix remodeling of transplanted biomaterials.

Recent Progress in Electrospun Polyacrylonitrile Nanofiber-Based Wound Dressing

Bleeding control plays a very important role in worldwide healthcare, which also promotes research and development of wound dressings. The wound healing process involves four stages of hemostasis, inflammation, proliferation and remodeling, which is a complex process, and wound dressings play a huge role in it. Electrospinning technology is simple to operate. Electrospun nanofibers have a high specific surface area, high porosity, high oxygen permeability, and excellent mechanical properties, which show great utilization value in the manufacture of wound dressings. As one of the most popular reactive and functional synthetic polymers, polyacrylonitrile (PAN) is frequently explored to create nanofibers for a wide variety of applications. In recent years, researchers have invested in the application of PAN nanofibers in wound dressings. Research on spun nanofibers is reviewed, and future development directions and prospects of electrospun PAN nanofibers for wound dressings are proposed.

Dual photothermal nanocomposites for drug-resistant infectious wound management

Management of antibiotic-resistant bacteria-induced skin infections for rapid healing remains a critical clinical challenge. Photothermal therapy, which uses mediated hyperthermia to combat such problems, has recently been recognised as a promising approach to take. In this study, bacterial cellulose-based photothermal membranes were designed and developed to combat bacterial infections and promote rapid wound healing. Polydopamine was incorporated into gold nanoparticles to produce superior dual-photothermal behaviour. The in vitro antibacterial efficacy of the prepared composite membranes against S. aureus, E. coli and methicillin-resistant Staphylococcus aureus (MRSA) could reach 99% under near-infrared (NIR) irradiation. In addition, the synthesised nanocomposite exhibited good biocompatibility in vitro as demonstrated by a cell survival ratio of >85%. The effectiveness of the composite membranes on wound healing was further investigated in a murine model of MRSA-infected wounds, focusing on the effect of photothermal temperature. According to the detailed therapeutic mechanism study undertaken, the composite membranes cause bacterial killing initially and promote the transition from the inflammatory phase to proliferation by suppressing pro-inflammatory cytokine production, promoting collagen deposition, and stimulating angiogenesis. Considering their remarkable effectiveness and facile fabrication process, it is expected that these novel materials could serve as competitive multifunctional dressings in the management of infectious wounds and accelerate the regeneration of damaged tissues related to abnormal immune responses.

Borrowing the Features of Biopolymers for Emerging Wound Healing Dressings: A Review

Wound dressing design is a dynamic and rapidly growing field of the medical wound-care market worldwide. Advances in technology have resulted in the development of a wide range of wound dressings that treat different types of wounds by targeting the four phases of healing. The ideal wound dressing should perform rapid healing; preserve the body’s water content; be oxygen permeable, non-adherent on the wound and hypoallergenic; and provide a barrier against external contaminants—at a reasonable cost and with minimal inconvenience to the patient. Therefore, choosing the best dressing should be based on what the wound needs and what the dressing does to achieve complete regeneration and restoration of the skin’s structure and function. Biopolymers, such as alginate (ALG), chitosan (Cs), collagen (Col), hyaluronic acid (HA) and silk fibroin (SF), are extensively used in wound management due to their biocompatibility, biodegradability and similarity to macromolecules recognized by the human body. However, most of the formulations based on biopolymers still show various issues; thus, strategies to combine them with molecular biology approaches represent the future of wound healing. Therefore, this article provides an overview of biopolymers’ roles in wound physiology as a perspective on the development of a new generation of enhanced, naturally inspired, smart wound dressings based on blood products, stem cells and growth factors.

Recent Advances in Honey-Based Nanoparticles for Wound Dressing: A Review

Wounds with impaired healing, including delayed acute injuries and chronic injuries, generally fail to progress through normal healing stages. A deeper understanding of the biochemical processes involved in chronic wound cures is necessary to correct the microenvironmental imbalances in the wound treatment designs of products. The therapeutic benefits of honey, particularly its antimicrobial activity, make it a viable option for wound treatment in a variety of situations. Integration with nanotechnology has opened up new possibilities not only for wound healing but also for other medicinal applications. In this review, recent advances in honey-based nanoparticles for wound healing are discussed. This also covers the mechanism of the action of nanoparticles in the wound healing process and perspectives on the challenges and future trends of using honey-based nanoparticles. The underlying mechanisms of wound healing using honey are believed to be attributed to hydrogen peroxide, high osmolality, acidity, non-peroxide components, and phenols. Therefore, incorporating honey into various wound dressings has become a major trend due to the increasing demand for combination dressings in the global wound dressing market because these dressings contain two or more types of chemical and physical properties to ensure optimal functionality. At the same time, their multiple features (low cost, biocompatibility, and swelling index) and diverse fabrication methods (electrospun fibres, hydrogels, etc.) make them a popular choice among researchers.

Development of antibacterial and superabsorbent wound composite sponges containing carboxymethyl cellulose/gelatin/Cu-doped ZnO nanoparticles

This study aimed to develop a novel antibacterial and superabsorbent dressing by introducing the Cu-doped ZnO nanoparticles into the carboxymethyl cellulose/gelatin glutaraldehyde-crosslinked composite sponge that is fabricated by lyophilization method. Undoped and Cu-doped ZnO (Zn_1-xCu_xO, x = 0.03 and 0.05) nanoparticles were synthesized through the stabilizing agent-used precipitation process and characterized by XRD, FESEM, FTIR, and ICP-OES techniques. The XRD evaluation determined that the concentration of copper in ZnO is limited to below 5%. Additionally, The ICP-OES analysis confirmed the effect of the doping process on the ZnO crystalline structure by releasing more zinc and copper ions from Cu-doped ZnO, which resulted to improve antibacterial activity against Staphylococcus aureus and Escherichia coli bacterial strains. The effect of ZnO nanoparticles on the physical and mechanical performance of the optimized composite sponge indicated that the incorporation of 3 wt% ZnO nanoparticles produces a well-interconnected porous structure (~156 µm) with high water absorption (~3089%) and proper elongation (~49%) in a wet medium. The incorporation of Cu-doped ZnO nanoparticles enhanced antibacterial potential of the composite sponge. Meanwhile, all sponge groups are safe for viability, proliferation and adhesion of human dermal fibroblast cells. Overall, the obtained data has proved the potential of carboxymethyl cellulose/gelatin/Cu-doped ZnO dressing as a promising candidate for managing infected wounds.

'Multiple and short-range' cross-linking of dialdehyde carboxymethyl cellulose contributes to regulating the physicochemical property of collagen fibril

Collagen fibril hydrogel (CH), with controllable micro-structure, sufficient modifying sites and excellent biocompatibility, has received widely attention in the regulation of biomacromolecules. Herein, dialdehyde carboxymethyl cellulose (DCMC) in different -CHO contents and molecular weights demonstrated two types of cross-linking behaviors to CH, 'limited and long-range' or 'multiple and short range' cross-linking, corresponding to -CHO content ranged from 0 to  53 % and 53- 90 %, respectively. In regard of structure, non-destroying effect of DCMC on collagen was supported by FT-IR and XRD analysis. CH cross-linked by DCMC (CH-DC) showed declining porosity and aggregating fibrils as -CHO content of DCMC rising. In regard of physicochemical properties, DCMC with >53 % -CHO strengthened the hydrophilicity, thermal stability and degradation resistance of CH-DC. Also, there was 110 % growth on gel strength, 86 Pa enhancements on storage modulus, and 4.6 times decrease on the swelling ratio of CH-DC. Results indicated that DCMC with 79 % -CHO remarkably improved the physicochemical properties of CH via developing sufficient Schiff-base bonds with collagen fibril in a short distance. This study distinguished two patterns of DCMC cross-linking from physicochemical view. In other words, DCMC is potential to meet the requirement of protein-based materials with different expectations by adjusting its -CHO content and molecular weight.

Electrospun Antibacterial Composites for Cartilage Tissue Engineering

Implantation of biomaterials capable of the controlled release of antibacterials during articular cartilage repair may prevent postoperative infections. Herein, biomaterials are prepared with biomimetic architectures (nonwoven mats of fibers) via electrospinning that are composed of poly(ɛ-caprolactone), poly(lactic acid), and Bombyx mori silk fibroin (with varying ratios) and, optionally, an antibiotic drug (cefixime trihydrate). The composition, morphology, and mechanical properties of the nanofibrous mats are characterized using scanning electron microscope, Fourier transform infrared spectroscopy, and tensile testing. The nonwoven mats have nanoscale fibers (typical diameters of 324-725 nm) and are capable of controlling the release profiles of the drug, with antibacterial activity against Gram +ve and Gram -ve bacteria (two common strains of human pathogenic bacteria, Staphylococcus aureus and Escherichia coli) under in vitro static conditions. The drug loaded nanofiber mats display cytocompatibility comparable to pure poly(ɛ-caprolactone) nanofibers when cultured with National Institutes of Health (NIH) NIH-3T3 fibroblast cell line and have long-term potential for clinical applications in the field of pharmaceutical sciences.

Functionalization of Electrospun Nanofiber for Bone Tissue Engineering

Bone-tissue engineering is an alternative treatment for bone defects with great potential in which scaffold is a critical factor to determine the effect of bone regeneration. Electrospun nanofibers are widely used as scaffolds in the biomedical field for their similarity with the structure of the extracellular matrix (ECM). Their unique characteristics are: larger surface areas, porosity and processability; these make them ideal candidates for bone-tissue engineering. This review briefly introduces bone-tissue engineering and summarizes the materials and methods for electrospining. More importantly, how to functionalize electrospun nanofibers to make them more conducive for bone regeneration is highlighted. Finally, the existing deficiencies of functionalized electrospun nanofibers for promoting osteogenesis are proposed. Such a summary can lay the foundation for the clinical practice of functionalized electrospun nanofibers.

A 3D Printed Bone Tissue Engineering Scaffold Composed of Alginate Dialdehyde-Gelatine Reinforced by Lysozyme Loaded Cerium Doped Mesoporous Silica-Calcia Nanoparticles

A novel biomaterial comprising alginate dialdehyde-gelatine (ADA-GEL) hydrogel augmented by lysozyme loaded mesoporous cerium doped silica-calcia nanoparticles (Lys-Ce-MSNs) was 3D printed to create bioactive scaffolds. Lys-Ce-MSNs raised the mechanical stiffness of the hydrogel composite scaffold and induced surface apatite mineralization, when the scaffold was immersed in simulated body fluid (SBF). Moreover, the scaffolds could co-deliver bone healing (Ca and Si) and antioxidant ions (Ce), and Lys to achieve antibacterial (and potentially anticancer) properties. The nanocomposite hydrogel scaffolds could hold and deliver Lys steadily. Based on the in vitro results, the hydrogel nanocomposite containing Lys assured improved pre-osteoblast cell (MC3T3-E1) proliferation, adhesion, and differentiation, thanks to the biocompatibility of ADA-GEL, bioactivity of Ce-MSNs, and the stabilizing effect of Lys on the scaffold structure. On the other hand, the proliferation level of MG63 osteosarcoma cells decreased, likely due to the anticancer effect of Lys. Last but not least, cooperatively, alongside gentamicin (GEN), Lys brought about a proper antibacterial efficiency to the hydrogel nanocomposite scaffold against gram-positive and gram-negative bacteria. Taken together, ADA-GEL/Lys-Ce-MSN nanocomposite holds great promise for 3D printing of multifunctional hydrogel BTE scaffolds, able to induce bone regeneration, address infection, and potentially inhibit tumor formation and growth. This article is protected by copyright. All rights reserved.

Keratin-based wound dressings: From waste to wealth

Keratin is a natural protein with a high content of cysteine residues (7-13%) and is widely found in hair, wool, horns, hooves, and nails. Keratin possesses abundant cell-binding motifs such as leucine-aspartate-valine (LDV), glutamate-aspartate-serine (EDS), and arginine-glycine-aspartate (RGD), which benefit cell attachment and proliferation. It has been confirmed that keratin plays important roles in every stage of wound healing, including hemostasis, inflammation, proliferation, and remodeling, making keratin-based materials good candidates for wound dressings. In combination with synthetic and natural polymers, keratin-based wound dressings in the forms of films, hydrogels, and nanofibers can be achieved with improved mechanical properties. This review focuses on the recent development of keratin-based wound dressings. Firstly, the physicochemical and biological properties of keratin, are systematically discussed. Secondly, the role of keratin in wound healing is proposed. Thirdly, the applications of keratin-based wound dressings are summarized, in terms of the forms and functionalization. Finally, the current challenges and future development of keratin-based wound dressings are presented.

Bacterial cellulose/soybean protein isolate composites with promoted inflammation inhibition, angiogenesis and hair follicle regeneration for wound healing

Soybean protein, as a safe and low-cost alternative to animal protein, attracts increasing attention in wound healing. In the present study, beta-conglycinin (7S) and glycinin (11S) with high solubility were obtained through separation of soybean protein. Afterward, 7S or 11S modified bacterial cellulose (BC) composites were produced by self-assembly method. Results confirmed the successful self-assembly of soybean protein isolates on the nanofibers of BC. The surface roughness and hydrophilicity of BC/7S and BC/11S decreased compared with native BC. Soybean protein could be steadily released from BC/7S and BC/11S and BC/11S released more soybean proteins than BC/7S. In vitro, BC/7S and BC/11S supported fibroblasts attachment and promoted fibroblasts proliferation and type I collagen expression. In vivo, BC/7S and BC/11S facilitated wound healing and collagen deposition, enhanced angiogenesis and hair follicle regeneration, as well as reduced scar formation and inflammation in full-thickness skin wounds of rats. Moreover, wounds treated with BC/11S showed a faster wound healing rate and more collagen depositions than those of BC/7S, which may be attributed to the larger considerable amount of soybean protein released by BC/11S. These results indicate that BC/7S and BC/11S are potential candidates for wound dressings.

Construction of multifunctional wound dressings with their application in chronic wound treatment

As the prevalence of diabetes increases year by year and the aging population continues to intensify in the world, chronic wounds such as diabetic foot ulcers and pressure ulcers have become serious problems that threaten people's health, and have brought an enormous burden to the world healthcare system. Conventional clinical treatment of chronic wounds relies on non-specific topical care (including debridement, infection/inflammation control, and frequent wound dressing changes), which can alleviate disease progression and reduce patient suffering to a certain extent, but the overall cure rate is less than 50% and the recurrence rate is high. Traditional wound dressings such as gauze, hydrocolloids, films and foams are single-function, acting as a physical barrier or absorbing exudates, and cannot meet all the needs of the entire chronic wound healing process. Recently, a large number of novel functional dressings have been reported for chronic wound repair. Based on the progress on wound dressings in recent years and the relevant research experience of our group, the review summarizes and discusses the progress on multifunctional wound dressings (such as microneedles, sponges and hydrogels) with anti-inflammatory, antioxidant, antibacterial, pro-angiogenic and tissue adhesive functions in detail. At the same time, the various responsive mechanisms (in vivo microenvironment or in vitro stimulation) of the smart multifunctional wound dressing are also analyzed in detail. It is expected that the review could provide some inspiration and suggestions for research on dressings for chronic wound treatment.

Antibacterial Activity of Electrospun Polyacrylonitrile Copper Nanoparticle Nanofibers on Antibiotic Resistant Pathogens and Methicillin Resistant Staphylococcus aureus (MRSA)

Bacteria induced diseases such as community-acquired pneumonia (CAP) are easily transmitted through respiratory droplets expelled from a person’s nose or mouth. It has become increasingly important for researchers to discover materials that can be implemented in in vitro surface contact settings which disrupt bacterial growth and transmission. Copper (Cu) is known to have antibacterial properties and have been used in medical applications. This study investigates the antibacterial properties of polyacrylonitrile (PAN) based nanofibers coated with different concentrations of copper nanoparticles (CuNPs). Different concentrations of copper sulfate (CuSO₄) and polyacrylonitrile (PAN) were mixed with dimethylformamide (DMF) solution, an electrospinning solvent that also acts as a reducing agent for CuSO₄, which forms CuNPs and Cu ions. The resulting colloidal solutions were electrospun into nanofibers, which were then characterized using various analysis techniques. Methicillin-Resistant isolates of Staphylococcus aureus, an infective strain that induces pneumonia, were incubated with cutouts of various nanocomposites using disk diffusion methods on Luria-Bertani (LB) agar to test for the polymers’ antibacterial properties. Herein, we disclose that PAN-CuNP nanofibers have successfully demonstrated antibacterial activity against bacteria that were otherwise resistant to highly effective antibiotics. Our findings reveal that PAN-CuNP nanofibers have the potential to be used on contact surfaces that are at risk of contracting bacterial infections, such as masks, in vivo implants, or surgical intubation.

Electrospinning-Generated Nanofiber Scaffolds Suitable for Integration of Primary Human Circulating Endothelial Progenitor Cells

The extracellular matrix is fundamental in order to maintain normal function in many organs such as the blood vessels, heart, liver, or bones. When organs fail or experience injury, tissue engineering and regenerative medicine elicit the production of constructs resembling the native extracellular matrix, supporting organ restoration and function. In this regard, is it possible to optimize structural characteristics of nanofiber scaffolds obtained by the electrospinning technique? This study aimed to produce partially degraded collagen (gelatin) nanofiber scaffolds, using the electrospinning technique, with optimized parameters rendering different morphological characteristics of nanofibers, as well as assessing whether the resulting scaffolds are suitable to integrate primary human endothelial progenitor cells, obtained from peripheral blood with further in vitro cell expansion. After different assay conditions, the best nanofiber morphology was obtained with the following electrospinning parameters: 15 kV, 0.06 mL/h, 1000 rpm and 12 cm needle-to-collector distance, yielding an average nanofiber thickness of 333 ± 130 nm. Nanofiber scaffolds rendered through such electrospinning conditions were suitable for the integration and proliferation of human endothelial progenitor cells.

Eggshell membrane-mimicking multifunctional nanofiber for in-situ skin wound healing

Eggshell membrane is a naturally-occurring protective barrier layer for chickens' incubation and shows the close similarity with extracellular matrix. To fully explore and utilize its' structure and active components via a mimicking way will be of great interest for wounds healing. Herein, the well-dispersed CuS nanoparticles were prepared by using eggshell membranes as templates with strong near-infrared absorption and photothermal properties. Furthermore, the as-prepared solution was combined with polyvinyl pyrrolidone and chitosan-derived fluorescent carbon dots for the mimetic synthesis of multifunctional nanofibrous membrane by a hand-held electrospinning device, which has the merits of in-situ operation, the extracellular matrix (ECM)-like architecture, hemostatic, radical scavenging, antibacterial, as well as accelerated healing of skin injury, etc. The electrospun-nanofiber membrane with optimal addition of 100 mg/L CuS nanoparticles was confirmed to be noncytotoxic on human fibroblasts and showed strong antibacterial activities against S. aureus and E. coli under NIR irradiation (980 nm). In addition, the radical scavenging ability was also proved by DPPH experiments. The animal experiments revealed that the nanofiber membrane could accelerate the wound healing process. The work lays down a simple and environmentally-friendly approach for the fabrication and development of promising wound healing materials in skin tissue engineering applications.

Polydopamine Biomaterials for Skin Regeneration

Designing biomaterials capable of biomimicking wound healing and skin regeneration has been receiving increasing attention recently. Some biopolymers behave similarly to the extracellular matrix (ECM), supporting biointerfacial adhesion and intrinsic cellular interactions. Polydopamine (PDA) is a natural bioadhesive and bioactive polymer that endows high chemical versatility, making it an exciting candidate for a wide range of biomedical applications. Moreover, biomaterials based on PDA and its derivatives have near-infrared (NIR) absorption, excellent biocompatibility, intrinsic antioxidative activity, antibacterial activity, and cell affinity. PDA can regulate cell behavior by controlling signal transduction pathways. It governs the focal adhesion behavior of cells at the biomaterials interface. These features make melanin-like PDA a fascinating biomaterial for wound healing and skin regeneration. This paper overviews PDA-based biomaterials' synthesis, properties, and interactions with biological entities. Furthermore, the utilization of PDA nano- and microstructures as a constituent of wound-dressing formulations is highlighted.

Antimicrobial Peptide-Tether Dressing Able to Enhance Wound Healing by Tissue Contact

No effective therapeutic dressings are currently available in the market that can prevent bacterial infection and simultaneously promote skin regeneration in diabetic patients. The lack of re-epithelization, prevalence of inflammation, and high risk of infection are hallmarks of non-healing wounds. Here, we have evaluated the antimicrobial and pro-regenerative effect of a relatively non-leaching LL37 peptide immobilized in polyurethane (PU)-based wound dressings (PU-adhesive-LL37 dressing). The PU-adhesive-LL37 (63 μg LL37NPs/cm²) dressing killed Gram-positive and Gram-negative bacteria in human serum without inducing bacterial resistance after 16 antimicrobial test cycles in contrast to commercially available dressings with the capacity to release antimicrobial Ag ions. Importantly, type II diabetic mice (db/db mice) treated with the PU-adhesive-LL37 dressing for different periods of time (6 or 14 days) showed enhanced wound healing and re-epithelialization (i.e., high keratin 14/5 levels) and lower macrophage infiltration in the wounds compared to animals treated with PU. The wounds treated with PU-adhesive-LL37 dressings showed also low expression of pro-inflammatory cytokines such as TNF-α and IL6 after 6 days of treatment, indicating that they act as an anti-inflammatory dressing. Additionally, PU-adhesive-LL37 dressings do not induce acute inflammatory responses in the peripheral blood mononuclear cells (PBMCs) after 3 days of exposure, in contrast to controls. Taken together, PU-adhesive-LL37NP dressings might prevent the bacterial infections and facilitate wound healing by tissue contact, inducing re-epithelialization and anti-inflammatory processes in diabetic conditions.

Ceramic Nanofiber Materials for Wound Healing and Bone Regeneration: A Brief Review

Ceramic nanofibers have been shown to be a new horizon of research in the biomedical area, due to their differentiated morphology, nanoroughness, nanotopography, wettability, bioactivity, and chemical functionalization properties. Therefore, considering the impact caused by the use of these nanofibers, and the fact that there are still limited data available in the literature addressing the ceramic nanofiber application in regenerative medicine, this review article aims to gather the state-of-the-art research concerning these materials, for potential use as a biomaterial for wound healing and bone regeneration, and to analyze their characteristics when considering their application.

Antitumor Efficacy of Doxorubicin-Loaded Electrospun Attapulgite–Poly(lactic-co-glycolic acid) Composite Nanofibers

Currently, cancer chemotherapeutic drugs still have the defects of high toxicity and low bioavailability, so it is critical to design novel drug release systems for cancer chemotherapy. Here, we report a method to fabricate electrospun drug-loaded organic/inorganic hybrid nanofibrous system for antitumor therapy applications. In this work, rod-like attapulgite (ATT) was utilized to load a model anticancer drug doxorubicin (DOX), and mixed with poly(lactic-co-glycolic acid) (PLGA) to form electrospun hybrid nanofibers. The ATT/DOX/PLGA composite nanofibers were characterized through various techniques. It is feasible to load DOX onto ATT surfaces, and the ATT/DOX/PLGA nanofibers show a smooth and uniform morphology with improved mechanical durability. Under neutral and acidic pH conditions, the loaded DOX was released from ATT/DOX/PLGA nanofibers in a sustained manner. In addition, the released DOX from the nanofibers could significantly inhibit the growth of tumor cells. Owing to the significantly reduced burst release profile and increased mechanical durability of the ATT/DOX/PLGA nanofibers, the designed organic–inorganic hybrid nanofibers may hold great promise as a nanoplatform to encapsulate different drugs for enhanced local tumor therapy applications.

Applications of Chitosan and its Derivatives in Skin and Soft Tissue Diseases

Chitosan and its derivatives are bioactive molecules that have recently been used in various fields, especially in the medical field. The antibacterial, antitumor, and immunomodulatory properties of chitosan have been extensively studied. Chitosan can be used as a drug-delivery carrier in the form of hydrogels, sponges, microspheres, nanoparticles, and thin films to treat diseases, especially those of the skin and soft tissue such as injuries and lesions of the skin, muscles, blood vessels, and nerves. Chitosan can prevent and also treat soft tissue diseases by exerting diverse biological effects such as antibacterial, antitumor, antioxidant, and tissue regeneration effects. Owing to its antitumor properties, chitosan can be used as a targeted therapy to treat soft tissue tumors. Moreover, owing to its antibacterial and antioxidant properties, chitosan can be used in the prevention and treatment of soft tissue infections. Chitosan can stop the bleeding of open wounds by promoting platelet agglutination. It can also promote the regeneration of soft tissues such as the skin, muscles, and nerves. Drug-delivery carriers containing chitosan can be used as wound dressings to promote wound healing. This review summarizes the structure and biological characteristics of chitosan and its derivatives. The recent breakthroughs and future trends of chitosan and its derivatives in therapeutic effects and drug delivery functions including anti-infection, promotion of wound healing, tissue regeneration and anticancer on soft tissue diseases are elaborated.

Electrospun hierarchical structural films for effective wound healing

Patients with acute and chronic wounds have been increasing around the world, and the demand for wound treatment and care is also increasing. Therefore, a new nanofiber wound dressing should be prepared to promote the wound healing process. In this study, we report the design and preparation of a hierarchical structural film wound dressing. The top layer is composed of profoundly hydrophobic polycaprolactone (PCL), which is used to resist the adhesion of external microorganisms. The bottom layer is made of hydrophilic gelatin, which provides a moist healing environment for the wound. The middle layer is composed of hydrophilic Janus nanofibers prepared with the latest side-by-side electrospinning technique. Gelatin and PCL are used as polymer matrices loaded with the ciprofloxacin (CIP) drug and zinc oxide nanoparticles (n-ZnO), respectively. Test results show that the dressing has outstanding surface wettability, excellent mechanical properties, and rapid drug release. The presence of biologically active ingredients provides antibacterial activity against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli). Finally, the results of wound healing in mice show accelerated collagen deposition, promotion of angiogenesis, and complete wound healing within 14 days. Overall, this hierarchical structural dressing has a strong potential for accelerating wound healing.

Multistage-Split Ultrafine Fluffy Nanofibrous Membrane for High-Efficiency Antibacterial Air Filtration

Antibacterial air filtration membranes are essential for personal protection during the pandemic of coronavirus disease 2019 (COVID-19). However, high-efficiency filtration with low pressure drop and effective antibiosis is difficult to achieve. To solve this problem, an innovative electrospinning system with low binding energy and high conductivity was built to enhance the jet splitting, and a fluffy nanofibrous membrane containing numerous ultrafine nanofibers and large quantities of antibacterial agents was achieved, which was fabricated by electrospinning polyamide 6 (PA6), poly(vinyl pyrrolidone) (PVP), chitosan (CS), and curcumin (Cur). The filtration efficiency for 0.3 μm NaCl particles was 99.83%, the pressure drop was 54 Pa, and the quality factor (QF) was up to 0.118 Pa^-1. CS and Cur synergistically enhanced the antibacterial performance; the bacteriostatic rates against Escherichia coli and Staphylococcus aureus were 99.5 and 98.9%, respectively. This work will largely promote the application of natural antibacterial agents in the development of high-efficiency, low-resistance air filters for personal protection by manufacturing ultrafine nanofibers with enhanced antibiosis.

An Overview on the Recent Advances in the Treatment of Infected Wounds: Antibacterial Wound Dressings

A wound can be surgical, cuts from an operation or due to accident and trauma. The infected wound, as a result of bacteria growth within the damaged skin, interrupts the natural wound healing process and significantly impacts the quality of life. Wound dressing is an important segment of the skincare industry with its economic burden estimated at $ 20.4 billion (in 2021) in the global market. The results of recent clinical trials suggest that the use of modern dressings can be the easiest, most accessible, and most cost-effective way to treat chronic wounds and, hence, holds significant promise. With the sheer number of dressings in the market, the selection of correct dressing is confusing for clinicians and healthcare workers. The aim of this research was to review widely used types of antibacterial wound dressings, as well as emerging products, for their efficiency and mode of action. In this review, we focus on introducing antibiotics and antibacterial nanoparticles as two important and clinically widely used categories of antibacterial agents. The perspectives and challenges for paving the way for future research in this field are also discussed. This article is protected by copyright. All rights reserved.

CHARACTERISTICS OF WOUND INFECTIONS AND METHODS OF THEIR TREATMENT USING PREPARATIONS OF BIOLOGICAL ORIGIN

Surgical wound infections are the most common patients’ complications in the postoperative period. In the modern clinic, they worsen the disease prognosis and remain the most important and acute health problem in all countries of the world. The aim of the work was to analyze current scientific data on the peculiarities of the pathogenesis of wound infections and types of their pathogens, as well as drugs of biological origin in the treatment of wound infections. The paper discusses in detail the problem of infection of wound injuries during surgery and domestic injuries of various kinds. The main pathogens of wound infections are considered. Specific pathogenicity factors for bacteria of the genera Staphylococcus, Pseudomonas, Enterobacteriaceae were analyzed. Based on the analysis of literature sources, a list of drugs of biotechnological origin that can be effectively used in combination therapy for the treatment and prevention of wound infections was determined. Conclusions. The result is the identification of those mechanisms of pathogenesis of wound infections that determine the effectiveness of the use of drugs of biological origin in this pathology treatment.

Melittin from Bee Venom Encapsulating Electrospun Fibers as a Potential Antimicrobial Wound Dressing Patches for Skin Infections

Skin infection compromises the body’s natural defenses. Several antibiotics are no longer effective owing to the evolution of antimicrobial-resistant (AMR) bacteria, hence, the constant development of novel antibacterial agents. Naturally occurring antibacterial agents may be potential candidates for AMR bacterial infection treatments; however, caution should be taken when administering such agents due to the high incidence of toxicity. A fibrous material system from a biocompatible polymer that could be used as a skin patch for skin infections treatment caused by AMR bacteria is proposed in this study. Bee venom’s active ingredient, melittin, was fabricated using electrospinning technology. Scanning electron microscopy showed that melittin-loaded fibers had smooth surfaces with no signs of beads or pores. The average diameter of this fibrous system was measured to be 1030 ± 160 nm, indicating its successful preparation. The melittin fibers’ drug loading and entrapment efficiency (EE%) were 49 ± 3 µg/mg and 84 ± 5%, respectively. This high EE% can be another successful preparatory criterion. An in vitro release study demonstrated that 40% of melittin was released after 5 min and achieved complete release after 120 min owing to the hydrophilic nature of the PVP polymer. A concentration of ≤10 µg/mL was shown to be safe for use on human dermal fibroblasts HFF-1 after 24-h exposure, while an antibacterial MIC study found that 5 μg/mL was the effective antimicrobial concentration for S. aureus, A. baumannii, E. coli and Candida albicans yeast. A melittin-loaded fibrous system demonstrated an antibacterial zone of inhibition equivalent to the control (melittin discs), suggesting its potential use as a wound dressing patch for skin infections.

A Multifunctional Janus Electrospun Nanofiber Dressing with Biofluid Draining, Monitoring, and Antibacterial Properties for Wound Healing

Wound healing greatly affects patients' health and produces medical burden. Therefore, we developed a multifunctional electrospun nanofiber dressing, which can inhibit methicillin-resistant Staphylococcus aureus (MRSA), drain excessive biofluid to promote wound healing, and simultaneously monitor wound pH level. The polyoxometalate (α-K₆P₂W₁₈O₆₂·14H₂O, P₂W₁₈) and oxacillin (OXA) are encapsulated in hydrophobic polylactide (PLA) nanofiber to synergistically inhibit MRSA. The phenol red (PSP) is encapsulated in hydrophilic polyacrylonitrile (PAN) nanofiber to sensitively indicate wound pH in situ. The PSP/PAN nanofiber is directly electrospun on the patterning OXA/P₂W₁₈/PLA nanofiber layer to form a Janus dressing. By taking advantage of the wettability difference between the two layers, the excess biofluid can be drained away from the wound. In addition, the Janus dressing exhibits good biocompatibility and accelerates wound healing via its antimicrobial activity and skin repairing function. This multifunctional Janus electrospun nanofiber dressing would be beneficial for wound management and treatment.

Evaluation of 20(S)-ginsenoside Rg3 loaded hydrogel for the treatment of perianal ulcer in a rat model

Background

As a kind of common complication of the surgery of perianal diseases, perianal ulcer is known as a nuisance. This study aims to develop a kind of 20(S)-ginsenoside Rg3 (Rg3)-loaded hydrogel to treat perianal ulcers in a rat model.

Methods

The copolymers PLGA₁₆₀₀-PEG₁₀₀₀-PLGA₁₆₀₀ were synthesized by ring-opening polymerization process and Rg3-loaded hydrogel was then developed. The perianal ulcer rat model was established to analyze the treatment efficacy of Rg3-loaded hydrogel for ulceration healing for 15 days. The animals were divided into control group, hydrogel group, free Rg3 group, Rg3-loaded hydrogel group, and Lidocaine Gel® group. The residual wound area rate was calculated and the blood concentrations of interleukin-1 (IL-1), interleukin-6 (IL-6), and vascular endothelial growth factor (VEGF) were recorded. Hematoxylin and eosin (H&E) staining, Masson's Trichrome (MT) staining, and tumor necrosis factor α (TNF-α), Ki-67, CD31, ERK1/2, and NF-κB immunohistochemical staining were performed.

Results

The biodegradable and biocompatible hydrogel carries a homogenous interactive porous structure with 10 μm pore size and five weeks in vivo degradation time. The loaded Rg3 can be released sustainably. The in vitro cytotoxicity study showed that the hydrogel had no effect on survival rate of murine skin fibroblasts L929. The Rg3-loaded hydrogel can facilitate perianal ulcer healing by inhibiting local and systematic inflammatory responses, swelling the proliferation of nuclear cells, collagen deposition, and vascularization, and activating ERK signal pathway.

Conclusion

The Rg3-loaded hydrogel shows the best treatment efficacy of perianal ulcer and may be a candidate for perianal ulcer treatment.

Fabrication of Biohybrid Nanofibers by the Green Electrospinning Technique and Their Antibacterial Activity

The development of bioactive polymer nanofiber sheets based on eco-friendly components is required to meet the needs of various medical applications as well as to preserve the environment. This study aimed to fabricate biohybrid nanofibers based on water-soluble polymers and aqueous extract of myrrh. The myrrh extract was incorporated into poly(vinyl alcohol)/tragacanth gum nanofiber mats (myrrh@PVA/TG) by the green electrospinning technique. Various characteristics of the prepared fibers such as morphology, fiber diameter distribution, crystallinity, and thermal stability were studied. The results confirmed that the morphology of biohybrid nanofibers was uniform without beads and tragacanth gum plays an important role in controlling the average diameter of fibers and the crystallinity. The antibacterial properties of the developed biohybrid nanofibers were investigated against common pathogens of Gram-positive and Gram-negative bacteria by the standard disc diffusion method. A significant antibacterial activity was observed toward bacterial strains after incorporation of aqueous myrrh extract into nanofibers, which increased on increasing the extract ratio. Due to their eco-friendly components and significant antibacterial activity, the prepared biohybrid nanofibers will open new avenues toward incorporating aqueous herbal extracts into degradable polymer fibers for use in many antibacterial applications.

S-nitrosoglutathione functionalized polydopamine nanoparticles incorporated into chitosan/gelatin hydrogel films with NIR-controlled photothermal/NO-releasing therapy for enhanced wound healing

Nitric oxide (NO) has aroused wide interest in the treating infected wounds due to its characteristic functionalities. However, its utilization is limited due to its volatile properties, high reactivity, direct potential toxicity, and byproducts of NO donors limited its application. Herein, endogenously NO donor S-nitrosoglutathione (GSNO) was connected covalently to polydopamine nanoparticles (PDA-GSNO NPs) to minimize the loss of NO in aqueous medium. Meanwhile, near-infrared (NIR)-controlled NO release and photothermal therapy (PTT) was obtained through the photothermal conversion by PDA. Then chitosan (CS)/gelatin (GE) biocomposite hydrogel films with preferable biocompatibility, surface hydrophilicity, hydroabsorptivity, and mechanical adhesive properties were constructed. By embedding PDA-GSNO NPs into the films, a multifunctional wound dressing was fabricated. Under NIR light irradiation, the combination of PTT, NO-releasing, and CS antibacterial agents can strengthen the in vitro antimicrobial efficacy and in vivo wound healing activities. Meanwhile, the obtained wound dressing presented good biocompatibility. This work outlines an approach for combating bacterial infections and demonstrating the possibility for synergistic NO-releasing wound healing.

Antibacterial composite hydrogels of graphene quantum dots and bacterial cellulose accelerate wound healing

The increased antibiotic resistance of pathogenic bacteria requires intense research of new wound healing agents. Novel wound dressings should be designed to provide wound disinfection, good moisture, and fast epithelization. In this study, bacterial cellulose (BC) was impregnated with graphene quantum dots (GQDs) for potential use in wound healing treatment. The BC was successfully loaded with approximately 11.7 wt% of GQDs. The actual release of GQDs from new designed composite hydrogels were 13%. Novel GQDs-BC hydrogel composites are biocompatible and showed significant inhibition towards Staphylococcus aureus and Streptococcus agalactiae and bactericidal effect towards Methicillin-resistant Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa. The in vitro healing analysis showed significant migration of human fibroblasts after the GQDs-BC hydrogels application. Furthermore, after 72 h exposure to GQDs-BC, endothelial nitric oxide synthase, vascular endothelial growth factor A, matrix metallopeptidase 9, and Vimentin gene expression in fibroblast were significantly upregulated promoting angiogenesis. GQDs-BC hydrogel composites showed very good wound fluid absorption and water retention, which satisfies good dressing properties. All obtained results propose new designed GQDs-BC hydrogels as potential wound dressings.

Synthesis of polyacrylonitrile/polytetrahydropyrimidine (PAN/PTHP) nanofibers with enhanced antibacterial and anti-viral activities for personal protective equipment

Emerging infectious diseases caused by the spread of bacteria and viruses are a major burden on global economic development and public health. At present, most personal protective equipment has weak antibacterial and anti-viral properties. The PAN/PTHP nanofibers reported in this article provide a new method for the development of personal protective equipment. In this study, a mixture of PTHP and PAN was prepared into PAN/PTHP nanofibers with high-efficiency and long-lasting antibacterial effects (>99.999%) through the electrospinning process. Live/dead staining and cell proliferation experiments showed that the preparation of PAN/PTHP nanofibers has good cell compatibility. In addition, PAN/PTHP nanofibers show obvious destructive effects on lentiviruses. Based on these characteristics, PAN/PTHP nanofibers were applied to facial masks, which can be used as the inflatable biocidal layer of facial masks and have an excellent interception effect on particles in the air. The successful synthesis of these fascinating materials may provide new insights for the development of new protective materials.