Electrospun mupirocin loaded polyurethane fiber mats for anti-infection burn wound dressing application

Synthesis and characterization of mupirocin-LDH/PVA nanofibrous composite as a dual-carrier drug release system

Nowadays, nanofibrous structures based on organic and inorganic materials are considered a drug delivery system for the controlled release of antibiotics and other antibacterial agents. The main goal of this research is a combination of the special properties of nanofibrous structure and Mupirocin-loaded Layered double hydroxide (LDH) to obtain a dual-carrier drug release system to provide long term antibacterial properties in wound healing process. Regards, unloaded layered double hydroxide (LDH) and Mupirocin-loaded LDH, which were synthesized by co-precipitation method, were added to Polyvinyl alcohol (PVA) solution in different mass ratio and electrospun using different processing conditions. The physico-chemical characterizations were performed using SEM, FTIR and tensile strength tests. The biological properties of the fabricated nanocomposites were evaluated using antibacterial test and in vitro cell culturing followed by MTT assay. The SEM results showed a bead-less and uniform morphology of nanofibrous composite containing Mupirocin(2.3 wt%)-LDH(15 wt%)/PVA with an average fiber diameter of about 270 ± 58 nm. According to the release study, the maximum release of the mupirocin drug was about 54 % in the first 6 h. The antibiogram analysis exhibited good antibacterial activity of mupirocin-loaded nanocomposite against both bacteria, especially gram-positive one. Finally, MTT assay approved the biocompatibility of the mupirocin-loaded nanocomposite. Overall, the produced nanofibrous composites would be a promising dual-carrier system for controlled release of antibiotic.

Recent progress of electrospun nanofibers as burning dressings

Burns are a global public health problem, which brings great challenges to public health and the economy. Severe burns often lead to systemic infection, shock, multiple organ failure, and even death. With the increasing demand for the therapeutic effect of burn wounds, traditional dressings have been unable to meet people's needs due to their single function and many side effects. In this context, electrospinning shows a great prospect on the way to open up advanced wound dressings that promote wound repairing and prevent infection. With its large specific surface area, high porosity, and similar to natural extracellular matrix (ECM), electrospun nanofibers can load drugs and accelerate wound healing. It provides a promising solution for the treatment and management of burn wounds. This review article introduces the concept of burn and the types of electrospun nanofibers, then summarizes the polymers used in electrospun nanofiber dressings. Finally, the drugs (plant extracts, small molecule drugs and nanoparticles) loaded with electrospun burn dressings are summarized. Some promising aspects for developing commercial electrospun burn dressings are proposed.

Mupirocin loaded core-shell pluronic-pectin-keratin nanofibers improve human keratinocytes behavior, angiogenic activity and wound healing

In the current study, a core-shell nanofibrous wound dressing based on Pluronic-F127 (F127) containing 2 wt% mupirocin (Mup) core and pectin (Pec)-keratin (Kr) shell was fabricated through coaxial electrospinning technique, and the blended nanofibers were also fabricated from the same materials. The fiber diameter and specific surface area of the blended nanofibers were about 101.56 nm and 20.16 m2/g, while for core-shell nanofibers they were about 97.32 nm and 25.26 m2/g, respectively. The resultant blended and core-shell nanofibers experienced a degradation of 27.65 % and 32.28 % during 7 days, respectively. The drug release profile of core-shell nanofibers revealed a sustained release of Mup over 7 days (87.66 %), while the blended F127-Pec-Kr-Mup nanofibers had a burst release within the first few hours (89.38 % up to 48 h) and a cumulative release of 91.36 % after 7 days. Due to the controlled release of Mup, the core-shell structure significantly improved the human keratinocytes behavior, angiogenic potential and wound healing in a rat model compared to the blended structure. In conclusion, the F127-Mup/Pec-Kr core-shell nanofibrous wound dressing appears to be a promising candidate for the prevention of infection, and can potentially accelerate the recovery and healing of chronic and ischemic wounds.

A bilayer mupirocin/bupivacaine-loaded wound dressing based on chitosan/poly (vinyl alcohol) nanofibrous mat: Preparation, characterization, and controlled drug release

An infected skin wound caused by external injury remains a serious challenge. Electrospun drug-loaded nanofibers with antibacterial properties based on biopolymers have been widely explored for wound healing. In this study, the double-layer CS/PVA/mupirocin (CPM) + CS/PVA/bupivacaine (CPB) mats were prepared by electrospinning method (20 % polymer weight) and then crosslinked with glutaraldehyde (GA) to optimize the water-resistant and biodegradation properties for wound dressing applications. The morphology of mats was characterized as defect-free and interconnected nanofibers by Scanning Electron Microscope (SEM) and Atomic Force Microscopy (AFM). Fourier Transform Infrared Spectrometry (FTIR) analysis also assessed the chemical structural properties. The porosity, surface wettability, and swelling degree of the dual-drug loaded mats were improved by about 20 %, 12°, and 200 % of the CS/PVA sample to provide a moist environment for efficient wound breathing and repairing. This highly porous mat facilitated the wound exudates absorption and air permeability excellently, reducing the chance of bacterial infections by inhibiting the growth of S. aureus bacterial colonies with a zone of 71.3 mm diameter. In vitro drug release results showed a high-burst release of 80 % and a continuous release profile for bupivacaine and mupirocin, respectively. MTT assay and in vivo tests indicated >90 % of cell viability and improvement in cell proliferation. It triply accelerated wound closure compared to the control group, reaching nearly full closure after 21 days as a potential clinical wound treatment.

Evaluation of Lactobacillus plantarum and PRGF as a new bioactive multi-layered scaffold PU/PRGF/gelatin/PU for wound healing

The effect of tissue engineering strategies in combination with Lactobacillus plantarum and platelet-rich growth factor (PRGF) with the aim of creating an appropriate wound dressing can be useful in wound healing and infection prevention in patients suffering from acute and chronic skin damages. Therefore, in this study, a new approach was employed to create a bioactive multilayer electrospun scaffold composed of polyurethane (PU), PRGF, and gelatin fibers, then human adipose-derived mesenchymal stem cells (hAMSCs), fibroblast cells (HU-02) and L. plantarum were cultured on the scaffold. The physicochemical properties, biocompatibility, and antibacterial activity of the scaffold were evaluated. In addition, the expression of the migration and proliferation genes of fibroblast cells were investigated by real-time PCR (polymerase chain reaction). Mitochondrial activity assays revealed that PRFG and L. plantarum had a significant positive effect on the viability of target co-cultured cells.Fluorescent and SEM (scanning electron microscopy) images presented the cells and bacterial proliferation and adhesion in hydrophilic scaffolds within 21 days. The sustained release of PRGF from scaffolds with a zero-order pattern was confirmed. RT-PCR analysis revealed that PRGF elevated the expression of VEGF genes up to fourfold, but L. plantarum had a better effect on DDR2 gene expression compared to the TCPS group. Antibacterial tests showed that L. plantarum has a bacterial load reduction of more than 70% in CFU/mL. The present scaffold is an appropriate model for cell attachment, migration, proliferation, and infection prevention.

Wound healing and antibacterial capability of electrospun polyurethane nanofibers incorporating Calendula officinalis and Propolis extracts

In order to produce a healing accelerator antibacterial wound dressing, different electrospun polyurethane (PU)-based nanofibers inclusive Calendula officinalis and Propolis ethanolic extracts were fabricated. The measurement of minimum inhibitory concentrations (MIC) against Methicillin-resistant Staphylococcus aureus (MRSA) determined the concentrations of incorporating extracts. Then the morphological properties of the produced polyurethane (PU), polyurethane/C. officinalis (PU/CO), polyurethane/Propolis (PU/PR), polyurethane/C. officinalis/Propolis (PU/CO/PR) were analyzed by scanning electron microscopy (SEM). The physicochemical features and biological characteristics of the fabricated nanofibers were evaluated. Subsequently, the antibacterial and wound-healing efficiency of electrospun wound dressings were tested under in vivo situation. The electrospun PU/CO/PR nanofiber illustrated the most degree of antibacterial, antioxidant, and cell proliferation efficiencies. In vivo examination and histological analysis confirmed significant improvement in the complete, well-organized wound-healing process in MRSA-infected wounds treated with PU/CO/PR. These outcomes described PU/CO/PR electrospun nanofibers as a wound dressing that can significantly facilitate wound healing with notable antibacterial, antioxidant, and cell proliferation properties.

Rational design of biodegradable thermoplastic polyurethanes for tissue repair

As a type of elastomeric polymers, non-degradable polyurethanes (PUs) have a long history of being used in clinics, whereas biodegradable PUs have been developed in recent decades, primarily for tissue repair and regeneration. Biodegradable thermoplastic (linear) PUs are soft and elastic polymeric biomaterials with high mechanical strength, which mimics the mechanical properties of soft and elastic tissues. Therefore, biodegradable thermoplastic polyurethanes are promising scaffolding materials for soft and elastic tissue repair and regeneration. Generally, PUs are synthesized by linking three types of changeable blocks: diisocyanates, diols, and chain extenders. Alternating the combination of these three blocks can finely tailor the physio-chemical properties and generate new functional PUs. These PUs have excellent processing flexibilities and can be fabricated into three-dimensional (3D) constructs using conventional and/or advanced technologies, which is a great advantage compared with cross-linked thermoset elastomers. Additionally, they can be combined with biomolecules to incorporate desired bioactivities to broaden their biomedical applications. In this review, we comprehensively summarized the synthesis, structures, and properties of biodegradable thermoplastic PUs, and introduced their multiple applications in tissue repair and regeneration. A whole picture of their design and applications along with discussions and perspectives of future directions would provide theoretical and technical supports to inspire new PU development and novel applications.

Wearable adjunct ozone and antibiotic therapy system for treatment of Gram-negative dermal bacterial infection

The problematic combination of a rising prevalence of skin and soft tissue infections and the growing rate of life-threatening antibiotic resistant infections presents an urgent, unmet need for the healthcare industry. These evolutionary resistances originate from mutations in the bacterial cell walls which prevent effective diffusion of antibiotics. Gram-negative bacteria are of special consideration due to the natural resistance to many common antibiotics due to the unique bilayer structure of the cell wall. The system developed here provides one solution to this problem through a wearable therapy that delivers and utilizes gaseous ozone as an adjunct therapy with topical antibiotics through a novel dressing with drug-eluting nanofibers (NFs). This technology drastically increases the sensitivity of Gram-negative bacteria to common antibiotics by using oxidative ozone to bypass resistances created by the bacterial cell wall. To enable simple and effective application of adjunct therapy, ozone delivery and topical antibiotics have been integrated into a single application patch. The drug delivery NFs are generated via electrospinning in a fast-dissolve PVA mat without inducing decreasing gas permeability of the dressing. A systematic study found ozone generation at 4 mg/h provided optimal ozone levels for high antimicrobial performance with minimal cytotoxicity. This ozone treatment was used with adjunct therapy delivered by the system in vitro. Results showed complete eradication of Gram-negative bacteria with ozone and antibiotics typically used only for Gram-positive bacteria, which showed the strength of ozone as an enabling adjunct treatment option to sensitize bacteria strains to otherwise ineffective antibiotics. Furthermore, the treatment is shown through biocompatibility testing to exhibit no cytotoxic effect on human fibroblast cells.

Insights into the Design of Polyurethane Dressings Suitable for the Stages of Skin Wound-Healing: A Systematic Review

Dressings made with polyurethanes have been found to exhibit good and varied biological properties that make them good candidates for this application. However, as has been seen, the wound-healing process is complex, which includes four different stages. So far, the design and evaluation of polyurethane for wound dressing has focused on achieving good properties (mechanical, physicochemical, and biological), but each of them separates from the others or even directed at only one of the stages of skin wound-healing. Therefore, the aim of this systematic review is to explore the applications of polyurethanes in wound dressings and to determine whether could be designed to cover more than one stage of skin wound-healing. The PRISMA guidelines were followed. The current research in this field does not consider each stage separately, and the design of polyurethane dressings is focused on covering all the stages of wound healing with a single material but is necessary to replace polyurethanes in short periods of time. Additionally, little emphasis is placed on the hemostasis stage and further characterization of polyurethanes is still needed to correlate mechanical and physicochemical properties with biological properties at each stage of the wound-healing. Current research demonstrates an effort to characterize the materials physiochemically and mechanically, but in terms of their biological properties, most of the literature is based on the performance of histological tests of explants morphologically probing the compromised tissues, which give an indication of the potential use of polyurethanes in the generation of wound-healing dressings.

Synergistic gentamicin-photodynamic therapy against resistant bacteria in burn wound infections

BACKGROUND

Multi-resistant bacteria, a result of the abuse of antibiotics, have greatly frustrated the effectiveness of antibiotics and produced a variety of side-effects. The combination of antibiotics with other therapies like antimicrobial photodynamic therapy (aPDT) may provide a useful strategy for fighting resistant bacteria. Here, the synergistic bactericidal effects of toluidine blue (TB)-aPDT and gentamicin (GEN) were evaluated in vitro and in vivo.

METHODS

The Post-antibacterial effects were measured at 600 nm (OD600) by a microplate reader. The bacterial envelope and biofilm were observed by a field emission scanning electron microscope. The expression of oxidative stress and Agr system-related genes was analyzed by qRT-PCR after GEN combined with TB-aPDT (GEN&aPDT). Besides, the burn infection model was established to investigate the cloning efficiency of immobilized bacteria, wound healing and inflammatory factors in the lesions.

RESULTS

GEN&aPDT could inhibit the growth of S. aureus and multidrug-resistant S. aureus (MDR S. aureus) for up to 15 h, and destroyed the cell envelope and biofilm structure of S. aureus and MDR S. aureus. During the process, ROS played an important role, inducing oxidative stress and downregulating the expression of AgrA, AgrB and PSM in the Agr system, resulting in decreased bacterial virulence and infectivity. In addition, GEN&aPDT cotreatment could effectively promoted wound healing in burn-infected mice by reducing the numbers of bacterial colonization in the wound, decreasing the content of inflammatory factors, and increasing the expression of growth factors.

CONCLUSION

The present study confirmed a bactericidal synergy between GEN and aPDT in vitro and in vivo, therein, the oxidative stress exhibited an important role in decreasing bacterial virulence and infectivity, which may bring new ideas for the treatment of bacterial resistance.

Localized Delivery of Drugs through Medical Textiles for Treatment of Burns: A Perspective Approach

The topical delivery offers numerous benefits, such as the ability to deliver drugs specifically on site selectively, prevents fluctuations in the levels of the drug, improved compliance, and improved self-medication capacity. Skin is the main route of the administration of the drug delivery system (DDS) and burns mainly cause skin damage. A burn is a kind of damage caused to skin and tissues by fire, ice, electrical energy, pollutants, friction, and radiation. There are three different types of burns, including superficial epidermis burns, partial-thickness dermis that stretch to the papillary and reticular dermis, and full-thickness burns that cover the dermis whole. The objective of the present review article is to focus on fabrication techniques of medical textiles, different types of polymers used for designing medicated textiles, skin burn conditions, and application of medicated textiles for treatment of burn along with other applications. Cream, ointment, and gel are the dosage forms used in burns. Intravenous fluids, wound care, assorted antibiotics, surgical and alternative medicines, burned creams and salami, dressings can be used to treat wounds. Nanofibers are nanometer-specific fibers that encapsulate drugs inside them and cure wounds. Nanofibers have all the properties that speed up wound healing. The properties are mechanical integrity, proper timing of wound addiction, temperature homeostasis facilitation and gas exchange, absorption of exudates. The nanofibers have been used in burn care and have been highly efficient and non-toxic.

Fabrication and characterization of starch-TPU based nanofibers for wound healing applications

Wound dressings have undergone continuous and substantial evolution over time. Modern bandage materials constitute of electrospun biopolymers that enable rapid and effective wound healing due to the high surface area to volume ratio of the electrospun nanofibers and their porous structure. In the present study, nanofibrous bandages, containing a blend of starch-thermoplastic polyurethane (TPU), were developed by using the electrospinning technique. The electrospun nanofibrous mats were subsequently crosslinked with varying concentrations of glutaraldehyde in order to increase their water stability and mechanical properties. The nanofibrous bandages were characterized for their structural properties using SEM, FTIR, TGA, DSC, as well as for their water retention ability, water vapor transmission rate (WVTR), tensile strength and blood clotting efficiency. Cytotoxicity of the bandages was evaluated using human dermal fibroblast cells. Furthermore, the extent of wound healing enabled by the nanofibrous bandage was ascertained using Sprague-Dawley rats. The results revealed that the starch-TPU nanofibrous bandages facilitated enhanced wound-healing, as compared to the traditional dressing material, such as the cotton gauze.

Biodegradable engineered fiber scaffolds fabricated by electrospinning for periodontal tissue regeneration

Considering the specificity of periodontium and the unique advantages of electrospinning, this technology has been used to fabricate biodegradable tissue engineering materials for functional periodontal regeneration. For better biomedical quality, a continuous technological progress of electrospinning has been performed. Based on property of materials (natural, synthetic or composites) and additive novel methods (drug loading, surface modification, structure adjustment or 3 D technique), various novel membranes and scaffolds that could not only relief inflammation but also influence the biological behaviors of cells have been fabricated to achieve more effective periodontal regeneration. This review provides an overview of the usage of electrospinning materials in treatments of periodontitis, in order to get to know the existing research situation and find treatment breakthroughs of the periodontal diseases.

Electrospinning synthesis and assessment of physicochemical properties and biocompatibility of cobalt nitrate fibers for wound healing applications

The aim of this study was to develop polyurethane (PU) wound dressing incorporated with cobalt nitrate using electrospinning technique. The morphology analysis revealed that the developed composites exhibited reduced fiber and pore diameter than the pristine PU. The electrospun membranes exhibited average porosity in the range of 67% - 71%. Energy-dispersive X-ray spectra (EDS) showed the presence of cobalt in the PU matrix. The interaction of cobalt nitrate with PU matrix was evident in Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA). The contact angle results indicated the improved wettability of the prepared PU/cobalt nitrate composites (82° ± 2) than the pure PU (100° ± 1). The incorporation of cobalt nitrate into the PU matrix enhanced the surface roughness and mechanical strength as evident in the atomic force microscopy (AFM) and tensile test analysis. The blood compatibility assays revealed the anticoagulant nature of the prepared composites by displaying prolonged blood clotting time than the PU control. Further, the developed composite exhibited less toxicity nature as revealed in the hemolysis and cytotoxicity studies. It was observed that the PU wound dressing added with cobalt nitrate fibers exhibited enhanced physicochemical, better blood compatibility parameters and enhanced fibroblast proliferation rates which may serve as a potential candidate for wound dressings.

Electrospun Combination of Peppermint Oil and Copper Sulphate with Conducive Physico-Chemical properties for Wound Dressing Applications

The ultimate goal in tissue engineering is to fabricate a scaffold which could mimic the native tissue structure. In this work, the physicochemical and biocompatibility properties of electrospun composites based on polyurethane (PU) with added pepper mint (PM) oil and copper sulphate (CuSO₄) were investigated. Field Emission Electron microscope (FESEM) study depicted the increase in mean fiber diameter for PU/PM and decrease in fiber diameter for PU/PM/CuSO₄ compared to the pristine PU. Fourier transform infrared spectroscopy (FTIR) analysis revealed the formation of a hydrogen bond for the fabricated composites as identified by an alteration in PU peak intensity. Contact angle analysis presented the hydrophobic nature of pristine PU and PU/PM while the PU/PM/CuSO₄ showed hydrophilic behavior. Atomic force microscopy (AFM) analysis revealed the increase in the surface roughness for the PU/PM while PU/PM/CuSO₄ showed a decrease in surface roughness compared to the pristine PU. Blood compatibility studies showed improved blood clotting time and less toxic behavior for the developed composites than the pristine PU. Finally, the cell viability of the fabricated composite was higher than the pristine PU as indicated in the MTS assay. Hence, the fabricated wound dressing composite based on PU with added PM and CuSO₄ rendered a better physicochemical and biocompatible nature, making it suitable for wound healing applications.