Facile preparation of antibacterial, highly elastic silvered polyurethane nanofiber fabrics using silver carbamate and their dermal wound healing properties

Second Skin as Self-Protection Against γ-Hydroxybutyrate

γ-Hydroxybutyrate (GHB), a date-rape drug, causes certain symptoms, such as amnesia, confusion, ataxia, and unconsciousness, when dissolved in beverages and consumed by a victim. Commonly, assailants use GHB in secret for the crime of drug-facilitated sexual assault because it is tasteless, odorless, and colorless when dissolved in beverages. Generally, GHB detection methods are difficult to use promptly and secretly in situ and in real life because of the necessary detection equipment and low selectivity. To overcome this problem, we have developed a fast, simple, and easy-to-use second skin platform as a confidential self-protection platform that can detect GHB in situ or in real life without equipment. The second skin platform for naked-eye detection of GHB is fabricated with poly(vinyl alcohol) (PVA), polyurethane (PU), and polyacrylonitrile (PAN) included in the chemical receptor 2-(3-bromo-4-hydroxystyryl)-3-ethylbenzothiazol-3-ium iodide (BHEI). PAN conjugated with BHEI nanofibers (PB NFs) has various characteristics, such as ease of use, high sensitivity, and fast color change. PB NFs rapidly detected GHB at 0.01 mg/mL. Furthermore, the second-skin platform attached to the fingertip and wrist detected both 1 and 0.1 mg/mL GHB in solution within 50 s. The color changes caused by the interaction of GHB and the second skin platform cannot be stopped due to strong chemical reactions. In addition, a second skin platform can be secretly utilized in real life because it can recognize fingerprints and object temperatures. Therefore, the second skin platform can be used to aid daily life and prevent drug-facilitated sexual assault crime when attached to the skin because it can be exposed anytime and anywhere.

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.

Sustainable cycloaliphatic polyurethanes: from synthesis to applications

Polyurethanes (PUs) are a versatile and major polymer family, mainly produced via polyaddition between polyols and polyisocyanates. A large variety of fossil-based building blocks is commonly used to develop a wide range of macromolecular architectures with specific properties. Due to environmental concerns, legislation, rarefaction of some petrol fractions and price fluctuation, sustainable feedstocks are attracting significant attention, e.g., plastic waste and biobased resources from biomass. Consequently, various sustainable building blocks are available to develop new renewable macromolecular architectures such as aromatics, linear aliphatics and cycloaliphatics. Meanwhile, the relationship between the chemical structures of these building blocks and properties of the final PUs can be determined. For instance, aromatic building blocks are remarkable to endow materials with rigidity, hydrophobicity, fire resistance, chemical and thermal stability, whereas acyclic aliphatics endow them with oxidation and UV light resistance, flexibility and transparency. Cycloaliphatics are very interesting as they combine most of the advantages of linear aliphatic and aromatic compounds. This original and unique review presents a comprehensive overview of the synthesis of sustainable cycloaliphatic PUs using various renewable products such as biobased terpenes, carbohydrates, fatty acids and cholesterol and/or plastic waste. Herein, we summarize the chemical modification of the main sustainable cycloaliphatic feedstocks, synthesis of PUs using these building blocks and their corresponding properties and subsequently present their major applications in hot-topic fields, including building, transportation, packaging and biomedicine.

Recent Advances in Silver Nanoparticles Containing Nanofibers for Chronic Wound Management

Infections are the primary cause of death from burns and diabetic wounds. The clinical difficulty of treating wound infections with conventional antibiotics has progressively increased and reached a critical level, necessitating a paradigm change for enhanced chronic wound care. The most prevalent bacterium linked with these infections is Staphylococcus aureus, and the advent of community-associated methicillin-resistant Staphylococcus aureus has posed a substantial therapeutic challenge. Most existing wound dressings are ineffective and suffer from constraints such as insufficient antibacterial activity, toxicity, failure to supply enough moisture to the wound, and poor mechanical performance. Using ineffective wound dressings might prolong the healing process of a wound. To meet this requirement, nanoscale scaffolds with their desirable qualities, which include the potential to distribute bioactive agents, a large surface area, enhanced mechanical capabilities, the ability to imitate the extracellular matrix (ECM), and high porosity, have attracted considerable interest. The incorporation of nanoparticles into nanofiber scaffolds constitutes a novel approach to “nanoparticle dressing” that has acquired significant popularity for wound healing. Due to their remarkable antibacterial capabilities, silver nanoparticles are attractive materials for wound healing. This review focuses on the therapeutic applications of nanofiber wound dressings containing Ag-NPs and their potential to revolutionize wound healing.

Natural Additives Improving Polyurethane Antimicrobial Activity

In recent years, there has been a growing interest in using polymers with antibacterial and antifungal properties; therefore, the present review is focused on the effect of natural compounds on the antibacterial and antifungal properties of polyurethane (PUR). This topic is important because materials and objects made with this polymer can be used as antibacterial and antifungal ones in places where hygiene and sterile conditions are particularly required (e.g., in healthcare, construction industries, cosmetology, pharmacology, or food industries) and thus can become another possibility in comparison to commonly used disinfectants, which mostly show high toxicity to the environment and the human health. The review presents the possibilities of using natural extracts as antibacterial, antifungal, and antiviral additives, which, in contrast to the currently used antibiotics, have a much wider effect. Antibiotics fight bacterial infections by killing bacteria (bactericidal effect) or slowing and stopping their growth (bacteriostatic effect) and effect on different kinds of fungi, but they do not fight viruses; therefore, compounds of natural origin can find wide use as biocidal substances. Fungi grow in almost any environment, and they reproduce easily in dirt and wet spaces; thus, the development of antifungal PUR foams is focused on avoiding fungal infections and inhibiting growth. Polymers are susceptible to microorganism adhesion and, consequently, are treated and modified to inhibit fungal and bacterial growth. The ability of micro-organisms to grow on polyurethanes can cause human health problems during the use and storage of polymers, making it necessary to use additives that eliminate bacteria, viruses, and fungi.

Potent environmental-friendly virucidal medical textiles against coronavirus to combat infections during the COVID-19 pandemic

The sudden outburst of Coronavirus disease 19 or COVID-19 has raised serious awareness about viral contamination on the environment, which is one of the major causes of the disease. Transmission via contaminated surfaces has been recognized as a significant route for spreading the virus. To suppress and control the spread of SARS-CoV-2, potent virucidal finishing agents for decontamination of medical textiles are urgently required. In this study, an environmental-friendly, economical, non-toxic, and practical finishing on medical textiles with potent virucidal activity was proposed with the combined concepts of a new green synthesis of TiO2@Ag core-shell nanostructures using ascorbic acid reduction and UV-curing process. In order to evaluate efficiency of virucidal activity, effects of the amount of TiO2@Ag NPs and contact time were determined against the coronavirus following ISO 18184:2019 standard. The finishing agent exhibited an excellent 99.9% virucidal efficacy. The stability of virucidal activity and mechanical properties were determined under repeated washing. The finished fabrics had the ability to retain their virucidal activity and tensile strength through 20 washes. The results suggested that the finishing agent had great potential as a potent and non-toxic virucide against the coronavirus for medical textile applications.

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.

The biomedical potential of cellulose acetate/polyurethane nanofibrous mats containing reduced graphene oxide/silver nanocomposites and curcumin: Antimicrobial performance and cutaneous wound healing

In this study, nanofibrous scaffolds were prepared from polyurethane and cellulose acetate using electrospinning. Reduced graphene oxide/silver nanocomposites, rGO/Ag, were also used into the mats due to the strong antibacterial activity of rGO/Ag nanocomposites. In order to prevent the agglomeration of silver nanoparticles, AgNPs, the nanoparticles were decorated onto the reduced graphene oxide (rGO) sheets. Initially, Graphene oxide, briefly GO, was synthesized by the improved Hummer method. Then, nanocomposites of reduced graphene oxide were decorated with Ag and were fabricated via a green and facile hydrothermal method. Thereafter, the scaffold containing rGO/Ag nanocomposites, curcumin or both of them were prepared using the electrospinning method. The obtained scaffolds were characterized by scanning electron microscopy (SEM), contact angle, tensile analysis, porosity, and water vapor transmission rate (WVTR). 3-[4,5-Dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide assay, MTT, confirmed the biocompatibility of the composite nanofibers. The scaffolds were able to hinder both of the Gram-negative and Gram-positive bacteria through direct contact with them. In vivo histopathological studies indicated that the scaffold incorporated rGO/Ag nanocomposites and curcumin has the most effect on wound healing and can promote the healing rate of artificial wounds, which indicates the good biomedical potential of nanomaterial in wound healing.

Recent advances in biomaterials for 3D scaffolds: A review

Considering the advantages and disadvantages of biomaterials used for the production of 3D scaffolds for tissue engineering, new strategies for designing advanced functional biomimetic structures have been reviewed. We offer a comprehensive summary of recent trends in development of single- (metal, ceramics and polymers), composite-type and cell-laden scaffolds that in addition to mechanical support, promote simultaneous tissue growth, and deliver different molecules (growth factors, cytokines, bioactive ions, genes, drugs, antibiotics, etc.) or cells with therapeutic or facilitating regeneration effect. The paper briefly focuses on divers 3D bioprinting constructs and the challenges they face. Based on their application in hard and soft tissue engineering, in vitro and in vivo effects triggered by the structural and biological functionalized biomaterials are underlined. The authors discuss the future outlook for the development of bioactive scaffolds that could pave the way for their successful imposing in clinical therapy.

Surface functionalization of electrospun PAN nanofibers with ZnO-Ag heterostructure nanoparticles: synthesis and antibacterial study

In this work, we have prepared polyacrylonitrile (PAN) polymer nanofibers by electrospinning method. The surface of the electrospun PAN nanofibers membrane has been functionalized with ZnO-Ag heterostructure nanoparticles by using three different chemical pathways such as reflux, blending, hydrothermal methods and accordingly the prepared composite nanofibers membranes were named as PAN/ZnO-Ag (R), PAN/ZnO-Ag (B) and PAN/ZnO-Ag (H) respectively. The obtained heterostructure nanoparticles functionalized PAN nanofibers membranes were characterized using ATR-FTIR, XRD, FESEM and TEM analytical techniques. From the FESEM and TEM images it was clearly observed that 20-30 nm size spherical nanoparticles have been decorated uniformly on the surface of PAN nanofibers. XRD study confirmed the formation of ZnO-Ag mixed/hybrid nanoparticles on PAN nanofibers surface. The ZnO-Ag heterostructure nanoparticles functionalized PAN nanofibers membranes were used for antibacterial application. It was observed from inhibition zone study that the ZnO-Ag heterostructure nanoparticles functionalized PAN nanofibers membrane shows excellent antibacterial properties towards both gram-negative Escherichia coli and gram-positive Micrococcus luteus bacteria than their single component counterparts. Thus this study demonstrated the simple and cost-effective approach to develop antibacterial functional membrane that has many potential applications in water and air filtration, protective mask, textile and packaging industries.

Mussel-inspired fabrication of pH-sensitive biomimetic hydrogels based on greenhouse gas carbon dioxide

Biomimetic hydrogels were prepared from carbon dioxide using a facile method. The PPC block and catechol groups contained in PPC-PU-LDA enable the hydrogel to have good cell compatibility and adhesion.

Current advances in the catalytic conversion of carbon dioxide by molecular catalysts: an update

Recent advances (2015–) in the catalytic conversion of CO₂ by metal-based and metal-free systems are discussed.