Bacteria adhesion on the surface is an initial step to create biofouling, which may lead to a severe infection of living organisms and humans. This study is concerned with investigating the textile properties including wettability, porosity, total pore volume, and pore size in association with bacteria adhesion. As model bacteria, Gram-negative, rod-shaped Escherichia coli and the Gram-positive, spherical-shaped Staphylococcus aureus were used to analyze the adhesion tendency. Electrospun webs made from polystyrene and poly(lactic acid) were used as substrates, with modification of wettability by the plasma process using either O2 or C4F8 gas. The pore and morphological characteristics of fibrous webs were analyzed by the capillary flow porometer and scanning electron microscopy. The substrate’s wettability appeared to be the primary factor influencing the cell adhesion, where the hydrophilic surface resulted in considerably higher adhesion. The pore volume and the pore size, rather than the porosity itself, were other important factors affecting the bacteria adherence and retention. In addition, the compact spatial distribution of fibers limited the cell intrusion into the pores, reducing the total amount of adherence. Thus, superhydrophobic textiles with the reduced total pore volume and smaller pore size would circumvent the adhesion. The findings of this study provide informative discussion on the characteristics of fibrous webs affecting the bacteria adhesion, which can be used as a fundamental design guide of anti-biofouling textiles.

In the outbreak of COVID-19, the extended wear of single-use, disposable respirators was inevitable due to limited supplies. As a respirator is front-line protection against particulate matter, including bioaerosol and droplets, a comprehensive understanding for the reuse strategy is needed. In this study, eight different disinfection methods commonly applied for the reuse of respirators were compared for their influence on the filtration and bactericidal/bacteria removal performance, with in-depth discussion on the cause of effects. Treatments including oven-dry, ultraviolet irradiation (UV), microwaving, laundering with and without detergent, and immersion in hypochlorite, isopropanol, and ethanol were performed to respirators. Immersion in ethanol or isopropanol was effective for inactivation and removal of bacteria, yet such a treatment significantly deteriorated the filtration efficiency in about 20–28%, dissipating the surface charges. Laundering, while effective in removing the attached bacteria, triggered physical damage, leading to a possible reduction of filtration performance. A short-term oven-dry, UV irradiation, and microwaving mostly preserved the filtration performance, yet the drawback lied in the incomplete bactericidal efficiency. This study would contribute to the public health and safety by providing scientific background on the effect of disinfection treatment methods for respirators.

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Quantification of bacteria adhered on porous, multi-layered fibers is a challenging task. The goal of this study is to compare different assessment procedures on counting textile-adhered bacteria, and to guide relevant analytical techniques. Three different methods were compared in measuring the amount of Escherichia coli (E. coli) adhered to polymeric film and fibrous nonwovens. In the extraction method, the adhered bacteria were released with the assistance of surfactant/enzyme, where the measurement was rather reproducible. For colorimetric method, stained bacteria enabled direct visualization without needing to detach cells from the surface, yet the linearity of color absorbency to cell counts was limited. The microscopic analysis provided direct observation of bacterial distribution over the surface, but accurate quantification was not possible for porous, fibrous surfaces. This study intends to help choosing a suitable test method to accurately quantify the textile-adhered bacteria, as well as broadly impact the research on anti-bioadhesive surfaces.

Plant-derived monoterpenoids have been shown to possess various biological effects, providing a scientific basis for their potential usage as antibacterial agents. Therefore, considering problems surrounding bacteria′s antibacterial resistance, the utilization of natural antimicrobial compounds such as monoterpenoids in different industries has gained much attention. The aim of this study was to fabricate and characterize various concentrations of plant-derived monoterpenoids, geraniol (G) and carvacrol (C), loaded into poly(lactic acid) (PLA) nanofibers via emulsion electrospinning. The antibacterial activities of the fabricated nanofibers were evaluated using three types of antibacterial assays (inhibition zone tests, live/dead bacterial cell assays, and antibacterial kinetic growth assays). Among the samples, 10 wt% carvacrol-loaded PLA nanofibers (C10) had the most bactericidal activity, with the widest inhibition zone of 5.26 cm and the highest visible dead bacteria using the inhibition zone test and live/dead bacterial cell assay. In order to quantitatively analyze the antibacterial activities of 5 wt% carvacrol-loaded PLA nanofibers (C5), C10, 5 wt% geraniol-loaded PLA nanofibers (G5), and 10 wt% geraniol-loaded PLA nanofibers (G10) against E. coli and S.epidermidis, growth kinetic curves were analyzed using OD600. For the results, we found that the antibacterial performance was as follows: C10 > C5 > G10 > G5. Overall, carvacrol or geraniol-loaded PLA nanofibers are promising antibacterial materials for improving fiber functionality.