Decontamination Efficiency of Thermal, Photothermal, Microwave, and Steam Treatments for Biocontaminated Household Textiles.

With the outbreak of the COVID-19 pandemic, textile laundering hygiene has proved to be a fundamental measure in preventing the spread of infections. The first part of our study evaluated the decontamination efficiency of various treatments (thermal, photothermal, and microwave) for bio contaminated textiles. The effects on textile decontamination of adding saturated steam into the drum of a household textile laundering machine were investigated and evaluated in the second part of our study. The results show that the thermal treatment, conducted in a convection heating chamber, provided a slight reduction in efficiency and did not ensure the complete inactivation of Staphylococcus aureus on cotton swatches. The photothermal treatment showed higher reduction efficiency on contaminated textile samples, while the microwave treatment (at 460 W for a period of 60 s) of bio contaminated cotton swatches containing higher moisture content provided satisfactory bacterial reduction efficiency (more than 7 log steps). Additionally, the treatment of textiles in the household washing machine with the injection of saturated steam into the washing drum and a mild agitation rhythm provided at least a 7 log step reduction in S. aureus. The photothermal treatment of bio contaminated cotton textiles showed promising reduction efficiency, while the microwave treatment and the treatment with saturated steam proved to be the most effective.

Metallisation of Textiles and Protection of Conductive Layers: An Overview of Application Techniques.

The rapid growth in wearable technology has recently stimulated the development of conductive textiles for broad application purposes, i.e., wearable electronics, heat generators, sensors, electromagnetic interference (EMI) shielding, optoelectronic and photonics. Textile material, which was always considered just as the interface between the wearer and the environment, now plays a more active role in different sectors, such as sport, healthcare, security, entertainment, military, and technical sectors, etc. This expansion in applied development of e-textiles is governed by a vast amount of research work conducted by increasingly interdisciplinary teams and presented systematic review highlights and assesses, in a comprehensive manner, recent research in the field of conductive textiles and their potential application for wearable electronics (so called e-textiles), as well as development of advanced application techniques to obtain conductivity, with emphasis on metal-containing coatings. Furthermore, an overview of protective compounds was provided, which are suitable for the protection of metallized textile surfaces against corrosion, mechanical forces, abrasion, and other external factors, influencing negatively on the adhesion and durability of the conductive layers during textiles' lifetime (wear and care). The challenges, drawbacks and further opportunities in these fields are also discussed critically.

In-situ enzyme-initiated production of hexanal from sunflower oil and its release from double emulsion electrospun bio-active membranes.

The aim of the presented study was to evaluate the release of the enzymatically initiated production of hexanal from double emulsion electrospun bio-active membranes at a temperature of fruit storage. Among different formulations of water-in-oil (W1/O) primary emulsions, the emulsion composed of 12% w/v Tween20 and 0.1 M NaCl in water (W1) and 6% of poly(glycerol) poly(ricinoleate) dissolved in sunflower oil (O) using W1/O ratio of 80/20 (w/w) (Tween20-NaCl/6% PGPR) was selected, for further incorporation of enzymes, based on the lowest average droplet size (391.0 ± 15.6 nm), low polydispersity index (0.255 ± 0.07), and good gravitational stability also after 14 days. Both enzymes, lipase and lipoxygenase are needed to produce hexanal (up to 58 mg/L). Additionally, double emulsions were prepared with sufficient conductivity and viscosity using different W1/O to W2 ratios for electrospinning. From the selected electrospun membrane, up to 4.5 mg/L of hexanal was released even after 92 days.

Cell Electrospinning: A Mini-Review of the Critical Processing Parameters and Its Use in Biomedical Applications.

Functional tissue engineering is a widely studied area of research with increasing importance in regenerative medicine, as well as in the development of in vitro models used for drug discovery and mimicking diseased tissues, among other applications. Electrospinning (ES) is one of the most widely used methods in these fields. It has attracted considerable interest because it can produce materials resembling the extracellular matrix of native tissues. The micro/nanofibers produced by this method provide a cell-friendly environment that promotes cellular activities. Cell electrospinning (C-ES) is based on the fundamental ES process and enables the encapsulation of viable cells in a micro/nanofibrous mesh. In this review, the process of C-ES and the materials used in this process are discussed. This work also discusses the applications of C-ES in tissue engineering, focusing on recent advances in this field.

Screen-printing of chitosan and cationised cellulose nanofibril coatings for integration into functional face masks with potential antiviral activity.

Masks proved to be necessary protective measure during the COVID-19 pandemic, but they provided a physical barrier rather than inactivating viruses, increasing the risk of cross-infection. In this study, high-molecular weight chitosan and cationised cellulose nanofibrils were screen-printed individually or as a mixture onto the inner surface of the first polypropylene (PP) layer. First, biopolymers were evaluated by various physicochemical methods for their suitability for screen-printing and antiviral activity. Second, the effect of the coatings was evaluated by analysing the morphology, surface chemistry, charge of the modified PP layer, air permeability, water-vapour retention, add-on, contact angle, antiviral activity against the model virus phi6 and cytotoxicity. Finally, the functional PP layers were integrated into face masks, and resulting masks were tested for wettability, air permeability, and viral filtration efficiency (VFE). Air permeability was reduced for modified PP layers (43 % reduction for kat-CNF) and face masks (52 % reduction of kat-CNF layer). The antiviral potential of the modified PP layers against phi6 showed inhibition of 0.08 to 0.97 log (pH 7.5) and cytotoxicity assay showed cell viability above 70 %. VFE of the masks remained the same (~99.9 %), even after applying the biopolymers, confirming that these masks provided high level of protection against viruses.

Fabrication of Polysaccharide-Based Halochromic Nanofibers via Needle-Less Electrospinning and Their Characterization: A Study of the Leaching Effect.

Responsive materials, i.e., smart materials, have the ability to change their physical or chemical properties upon certain external signals. The development of nanofibrous halochromic materials, specifically combining the pH-sensitive functionality and unique nanofiber properties, could yield interesting new applications, especially when the common problem of dye leaching is successfully tackled. Therefore, in this article, we studied the fabrication process of polysaccharide-based halochromic nanofibrous materials by using a combination of various halochromic dyes (bromothymol blue, bromocresol green, and thymol blue) and cellulose acetate in a spinning solution using a one-pot strategy. The inhibition of leaching was addressed by using a complexing agent: poly-diallyl-dimethylammonium chloride (PDADMAC). The preparation of hybrid spinning solutions, their characterization, and ability to form continuous nanofibers were studied using a high production needle-less electrospinning system. The produced hybrid solutions and nanofibers were characterized, in terms of their rheological properties, chemical structure, morphology, and functionality. Fabricated nanofibrous halochromic structures show a clear color change upon exposure to different pH values, as well as the reduced leaching of dyes, upon the addition of a complexing agent. The leaching decreased by 61% in the case of bromocresol green, while, in the case of bromothymol blue and thymol blue, the leaching was reduced by 95 and 99%, respectively.

Electrospun nanofibrous composites from cellulose acetate / ultra-high silica zeolites and their potential for VOC adsorption from air.

The optimized preparation of novel electrospun nanofibrous composites from cellulose acetate (CA) and ultra-high silica zeolites (UHSZ) are reported as a promising material for the adsorption of Volatile Organic Compound (VOCs). Two types of UHSZs, i.e. silicalite and USY were prepared by hydrothermal crystallization while the fabrication of composites was performed using single needle and needle-less electrospinning systems, demonstrating the scalability of the composite fibres' manufactured. Herein, factors such as properties of spinning solutions and electrospinning process parameters were studied, as well as interactions between the CA and UHSZs. In addition, Quartz Crystal Microbalance - Dissipation technique (QCM-D) was employed with an aim to study the adsorption behaviour of newly developed composites using ammonia as a model pollutant. The QCM-D data revealed that the presence of UHSZs in the CA materials increased adsorption capacity, designating CA/UHSZ composites as potential materials suitable for a large-scale removal of VOCs from polluted air.

Defluorination of Polytetrafluoroethylene Surface by Hydrogen Plasma.

Defluorination of polytetrafluoroethylene (PTFE) surface film is a suitable technique for tailoring its surface properties. The influence of discharge parameters on the surface chemistry was investigated systematically using radio-frequency inductively coupled H2 plasma sustained in the E- and H-modes at various powers, pressures and treatment times. The surface finish was probed by X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS). The measurements of water contact angles (WCA) showed increased wettability of the pristine PTFE; however, they did not reveal remarkable modification in the surface chemistry of the samples treated at various discharge parameters. By contrast, the combination of XPS and ToF-SIMS, however, revealed important differences in the surface chemistry between the E- and H-modes. A well-expressed minimum in the fluorine to carbon ratio F/C as low as 0.2 was observed at the treatment time as short as 1 s when plasma was in the H-mode. More gradual surface chemistry was observed when plasma was in the E-mode, and the minimal achievable F/C ratio was about 0.6. The results were explained by the synergistic effects of hydrogen atoms and vacuum ultraviolet radiation.

A green approach to obtain stable and hydrophilic cellulose-based electrospun nanofibrous substrates for sustained release of therapeutic molecules.

Stable and (bio)-compatible nanofibrous matrices showing effective incorporation and release of nonsteroidal anti-inflammatory drugs (NSAIDs) hold a huge potential in tissue regeneration and wound healing. Herein, a two-step, water-based and needleless electrospinning method is used to fabricate thermally cross-linked multifunctional nanofibrous substrates from a hydrophilic cellulose derivative, i.e. carboxymethyl cellulose (CMC), and polyethylene glycol (PEG) with an in situ incorporated NSAID, diclofenac (DCF). Electrospun bi-component blend nanofibers, strongly linked together by ester bonds, with different degrees of cross-linking density are achieved by varying the concentrations of butanetetracarboxylic acid (BTCA, a green polycarboxylic cross-linker) and the sodium hypophosphite (SHP) catalyst, and the temperature. The results demonstrated that not only the dimensional stability and swelling properties could be better controlled but also the morphology, fiber diameter, surface area, pore volume, pore size, and functionality of the cross-linked nanofibers. Release kinetics of DCF from the nanofibrous substrates are controlled and prolonged up to 48 h, and the overall released mass of DCF decreased linearly with increasing cross-linking degree of BTCA and SHP. Fitting of release data using various kinetic models revealed that the release of DCF follows a non-Fickian (diffusion and erosion controlled) to Fickian mechanism (only diffusion-controlled process). Cell viability testing based on crystal violet dyeing showed that the DCF-incorporating nanofibers have excellent biocompatibility and no toxic effect on human skin fibroblast cells. Overall, the reported DCF-incorporating nanofibrous substrate demonstrates high potential to be used as a smart drug delivery system in wound healing, especially due to its noninvasive characteristics.

Novel electrospun fibers with incorporated commensal bacteria for potential preventive treatment of the diabetic foot.

AIM: A novel electrospun biocompatible nanofibrous material loaded with commensal bacteria for potential preventive treatment of the diabetic foot was developed. MATERIALS & METHODS: Two biocompatible polymers (carboxymethylcellulose and polyethylene oxide) were combined with a bacterium isolate from the skin located between the toes of a healthy adult (identified using a matrix-assisted laser desorption/ionization mass spectrometry-based method as a strain of Staphylococcus epidermidis). Higher bacteria loads in the material were assured through their encapsulation in polyethylenimine. The nanofibrous material was characterized using scanning electron microscopy, zeta-potential measurements and through evaluation of cell growth and viability. RESULTS & DISCUSSION: nanometer formation was confirmed using scanning electron microscopy, while the zeta-potential measurements revealed successful bacteria encapsulation. Viable and sufficiently growing cells were confirmed prior and after their incorporation. CONCLUSION: The prepared materials were proven suitable to deliver viable commensal bacteria in a comparable share to the Staphylococcaceae in the foot microbiome making this approach promising for preventive diabetic foot treatment.

Nanofibrous polysaccharide hydroxyapatite composites with biocompatibility against human osteoblasts.

Regenerative medicine has a high demand for defined scaffold materials that promote cell growth, stabilize the tissue during maturation and provide a proper three dimensional structure that allows the exchange of nutrients. In many instances nanofiber composites have already shown their potential for such applications. This work elaborates the development of polysaccharide based nanofibers with integrated hydroxyapatite nanoparticles. A detailed study on the formation of electrospun nanofibres from aqueous mixtures of carboxymethyl cellulose polyethylene oxide was performed. The influence of different processing conditions and spinning solution properties using a nozzle-less electrospinning device was systematically studied. Optimized parameters were used to incorporate hydroxyapatite nanoparticles into the fibers. Nanofibers were additionally hydrophobized with alkenyl succinic anhydride (ASA) to render them insoluble in water. The nanofiber webs were thoroughly investigated with respect to morphology, chemical composition and inorganic content. Time dependent biocompatibility testing of the materials with human bone-derived osteoblasts showed no significant reduction in cell viability for the developed materials composed of carboxymethyl cellulose/polyethyleneoxide. Cells grown on hydrophobized materials show similar viability as those grown on a commercial collagen/apatite matrix.

Use of polysaccharide based surfactants to stabilize organically modified clay particles aqueous dispersion.

Pure as well as organically modified clay minerals are widely applied particles in different research areas. For the incorporation of hydrophobic organically modified clay particles into the hydrogel matrix, a stable aqueous dispersion must be prepared. In this article we report on the stabilization of aqueous dispersions of hydrophobic organically modified clay particles by using a non-ionic polysaccharide-based surfactant system-Inutec SP1 (based on chicory inulin). Different concentrations of surfactants were tested. Properties of the particulate surfactant-stabilized aqueous colloidal system were determined by electrophoretic mobility and dynamic light scattering measurements. Determination of contact angles gave us insight into the particles' surface interaction ability with water and also some information regarding the conformation of adsorbed surfactant molecules on the particle surface. By using Inutec SP1, the wettability of clay particles was improved, particle size was reduced and consequently, enhancement of their dispersion ability in water-based systems was observed.