Face Masks in the New COVID-19 Normal: Materials, Testing, and Perspectives

In Situ Collection and SERS Detection of Nitrite in Exhalations on Facemasks Based on Wettability Differences

As one of the common carriers of biological information, along with human urine specimens and blood, exhaled breath condensate (EBC) carries reliable and rich information about the body's metabolism to track human physiological normal/abnormal states and environmental exposures. What is more, EBC has gained extensive attention because of the convenient and nondestructive sampling. Facemasks, which act as a physical filter barrier between human exhaled breath and inhaled substances from the external environment, are safe, noninvasive, and economic devices for direct sampling of human exhaled breath and inhaled substances. Inspired by the ability of fog collection of Namib desert beetle, a strategy for in situ collecting and detecting EBC with surface-enhanced Raman scattering is illustrated. Based on the intrinsic and unique wettability differences between the squares and the surrounding area of the pattern on facemasks, the hydrophilic squares can capture exhaled droplets and spontaneously enrich the analytes and silver nanocubes (AgNCs), resulting in good repeatability in situ detection. Using R6G as the probe molecule, the minimal detectable concentration can reach as low as 10-16 M, and the relative standard deviation is less than 7%. This proves that this strategy can achieve high detection sensitivity and high detection repeatability. Meanwhile, this strategy is applicable for portable nitrite analysis in EBC and may provide an inspiration for monitoring other biomarkers in EBC.

Enhanced and copper concentration dependent virucidal effect against SARS-CoV-2 of electrospun poly(vinylidene difluoride) filter materials

Virucidal filter materials were prepared by electrospinning a solution of 28 wt % poly(vinylidene difluoride) in N,N-dimethylacetamide without and with the addition of 0.25 wt %, 0.75 wt %, 2.0 wt %, or 3.5 wt % Cu(NO3)2 · 2.5H2O as virucidal agent. The fabricated materials had a uniform and defect free fibrous structure and even distribution of copper nanoclusters. X-ray diffraction analysis showed that during the electrospinning process, Cu(NO3)2 · 2.5H2O changed into Cu2(NO3)(OH)3. Electrospun filter materials obtained by electrospinning were essentially macroporous. Smaller pores of copper nanoclusters containing materials resulted in higher particle filtration than those without copper nanoclusters. Electrospun filter material fabricated with the addition of 2.0 wt % and 3.5 wt % of Cu(NO3)2 · 2.5H2O in a spinning solution showed significant virucidal activity, and there was 2.5 ± 0.35 and 3.2 ± 0.30 logarithmic reduction in the concentration of infectious SARS-CoV-2 within 12 h, respectively. The electrospun filter materials were stable as they retained virucidal activity for three months.

Effect of Face Masks on Voice Quality Associated with Young and Older Chinese Adult Speakers

OBJECTIVES

Face masks have become important after the pandemic, but the change in voice when wearing a face mask is still unclear. The study investigated the effect of face masks on the acoustic and perceptual characteristics of voice quality associated with young and older Chinese adults.

METHODS

Voice samples of the sustained vowel /a/ and continuous speech produced by 44 older and 61 young adults with and without an ASTM level-3 surgical face mask were recorded and analyzed. Perceptual and acoustic parameters including mean fundamental frequency (F0) and intensity, perturbation measures (jitter and shimmer), harmonic-to-noise ratio (HNR), smoothed cepstral peak prominence (CPPs), and long-term average spectrum (LTAS) measures were obtained and compared.

RESULTS

When comparing masked to unmasked voices, for both male and female speakers, F0 and intensity showed no significant changes, except for F0 of continuous speech, which increased significantly. Meanwhile, perturbation measures such as jitter and shimmer were reduced, while HNR and CPPs increased. In addition, LTAS measures included low-frequency mean spectral energy (MSE), high-frequency MSE, and spectral tilt (ST), which were different. For perceptual measures, the overall grade of dysphonia, and roughness were reduced, except for the breathiness among older male speakers, while the other vocal qualities were not changed. Between young and older speakers, significant differences in shimmer, CPPs, and perceived breathiness among male speakers, and low-frequency MSE among female speakers were found.

CONCLUSION

Wearing a surgical mask appeared to change the perceived voice quality. This is supported by the change in perturbation and LTAS measures, and HNR and CPPs values. In addition, some differences between young and older adults were observed. Oral Communication effectiveness may be affected when wearing surgical masks due to changes in voice quality. Additionally, clinicians need to exercise hightened caution in evaluating the voice quality of clients when wearing face masks.

Anti-proliferative, antimicrobial, DFT calculations, and molecular docking 3D scaffold based on sodium alginate, chitosan, neomycin sulfate and hydroxyapatite

3D multifunctional scaffold has been designed based on Cs/SA/NS/NPHA. Nanoparticles hydroxyapatite (NPHA) was prepared via precipitation method of sodium dihydrogen phosphate in presence calcium chloride. Different ratios of Chitosan (CS)/Sodium Alginate (SA) were used to prepare Cs/SA scaffolds in presence of CaCl2 as a cross linker. NPHA was incorporated in CS/SA scaffold and neomycin sulfate (NS) was added as an antimicrobial agent. The structure and surface morphology of the scaffolds were investigated via infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscope (SEM) and thermal gravimetric analysis (TGA) techniques. Additionally, Antimicrobial activity of the scaffold has evaluated against Gram- negative and Gram- positive bacteria. The result showed promising antimicrobial activity against Bacillus subtilis, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa and Candida albicans. Furthermore, cytotoxicity against MG63 osteosarcoma cell and fibroblast normal cell line has investigated. The result showed anti-proliferative against MG63. DFT calculations and molecular docking were used to study the reactivity of the compounds. The results exhibited that Cs/SA/NS/NPHA is potent expected to be used in bone tissue regeneration.

Purine-Doped g-C3N4-Modified Fabrics for Personal Protective Masks with Rapid and Sustained Antibacterial Activity

Protective masks are critical to impeding microorganism transmission but can propagate infection via pathogen buildup and face touching. To reduce this liability, we integrated electrospun photocatalytic graphitic carbon nitride (g-C3N4) nanoflakes into standard surgical masks to confer a self-sanitization capacity. By optimizing the purine/melamine precursor ratio during synthesis, we reduced the g-C3N4 band gap from 2.92 to 2.05 eV, eliciting a 4× increase in sterilizing hydrogen peroxide production under visible light. This narrower band gap enables robust photocatalytic generation of reactive oxygen species from environmental and breath humidity to swiftly eliminate accumulated microbes. Under ambient sunlight, the g-C3N4 nanocomposite mask layer achieved a 97% reduction in the bacterial viability during typical use. Because the optimized band gap also allows photocatalytic activity under shadowless lamp illumination, the self-cleaning functionality could mitigate infection risk from residual pathogens in routine hospital settings. Both g-C3N4 and polycaprolactone demonstrate favorable biocompatibility and biodegradability, making this approach preferable over current commercially available metal-based options. Given the abundance and low cost of these components, this scalable approach could expand global access to reusable self-sanitizing protective masks, serving as a sustainable public health preparedness measure against future pandemics, especially in resource-limited settings.

Potential health risks of microplastic fibres release from disposable surgical masks: Impact of repeated wearing and handling

Disposable surgical masks undeniably provide important personal protection in daily life, but the potential health risks by the release of microplastic fibres from masks should command greater attention. In this study, we conducted a microplastic fibre release simulation experiment by carrying masks in a pocket and reusing them, to reveal the number and morphological changes of microfibres released. Fourier transform infrared spectrometry, scanning electron microscopy, and optical microscopy were employed to analyse the physical and chemical characteristics of the mask fibres. The results indicated that the reuse of disposable masks led to a significant release of microplastic fibres, potentially leading to their migration into the respiratory system. Furthermore, the release of microplastic fibres increased with prolonged external friction, particularly when masks were stored in pockets. The large-scale release of microplastic fibres due to mask reuse raises concerns about potential health risks to the human respiratory system. The reuse of disposable masks should be also strictly avoided in daily life in the future. Furthermore, the current study also established a robust foundation for future research endeavours on health risks associated with microplastic fibres entering the respiratory system through improper mask usage.

Exploring the release mechanism of micro/nanoplastics from different layers of masks in water: towards reduction of plastic contamination in masks

During the COVID-19 pandemic, a substantial quantity of disposable face masks was discarded, consisting of three layers of nonwoven fabric. However, their improper disposal led to the release of microplastics (MPs) and nanoplastics (NPs) when they ended up in aquatic environments. To analyze the release kinetics and size characteristics of these masks, release experiments were performed on commercially available disposable masks over a period of 7 days and micro- and nanoplastic releases were detected using fiber counting and nanoparticle tracking analysis. The study's findings revealed that there was no significant difference (p > 0.05) in the quantity of MPs released among the layers of the masks. However, the quantity of NPs released from the middle layer of the mask was 25.9 ± 1.3 × 108 to 81.3 ± 5.3 × 108 particles/piece, significantly higher than the inner and outer layers (p < 0.05). The release process of micro/nanoplastics (M/NPs) from each layer of the mask followed the Elovich equation and the power function equation, indicating that the release was divided into two stages. MPs in the range of 1-500 µm and NPs in the range of 100-300 nm dominated the release from each layer of the mask, accounting for an average of 93.81% and 67.52%, respectively. Based on these findings, recommendations are proposed to reduce the release of M/NPs from masks during subsequent use.

Disposable surgical/medical face masks and filtering face pieces: Source of microplastics and chemical additives in the environment

The production and consumption of disposable face masks (DFMs) increased intensely during the COVID-19 pandemic, leading to a high amount of them being found in the terrestrial and aquatic environment. The main goal of this research study is to conduct a comparative evaluation of the water-leachability of microplastics (MPs) and chemical additives from various types of disposable surgical/medical face masks (MM DFMs) and filtering face pieces (FFPs). Fourier-Transform Infrared Spectroscopy was used for MPs analysis. Liquid Chromatography/High Resolution Mass Spectrometry was used to analyse analytes presented in the water-leachates of DFMs. FFPs released 3-4 times more microplastic particles compared to MM DFMs. The release of MPs into water from all tested DFMs without mechanical stress suggests potential MP contamination originating from the DFM production process. Our study for the first time identified bisphenol B (0.25-0.42 μg/L) and 1,4-bis(2-ethylhexyl) sulfosuccinate (163.9-115.0 μg/L) as leachables from MM DFMs. MPs in the water-leachates vary in size, with predominant particles <100 μm, and the release order from DFMs is MMIIR > MMII > FFP3>FFP2>MMI. The main type of microplastics identified in the water leachates of the investigated face masks was polypropylene, accounting for 93-97% for MM DFMs and 82-83% for FFPs. Other polymers such as polyethylene, polycarbonate, polyester/polyethylene terephthalate, polyamide/Nylon, polyvinylchloride, and ethylene-propylene copolymer were also identified, but in smaller amounts. FFPs released a wider variety and a higher percentage (17-18%) of other polymers compared to MM DFMs (3-7%). Fragments and fibres were identified in all water-leachate samples, and fragments, particularly debris of polypropylene fibres, were the most common MP morphotype. The findings in this study are important in contributing additional data to develop science-based policy recommendations on the health and environmental impacts of MPs and associated chemical additives originated from DFMs.

Effects of wastewater treatment plant effluent on microbial risks of pathogens and their antibiotic resistance in the receiving river

The increase in effluent discharge from wastewater treatment plants (WWTPs) into urban rivers has raised concerns about the potential effects on pathogen risks. This study utilized metagenomic sequencing combined with flow cytometry to analyze pathogen concentrations and antibiotic resistance in a typical effluent-receiving river. Quantitative microbial risk assessment (QMRA) was employed to assess the microbial risks of pathogens. The results indicated obvious spatial-temporal differences (i.e., summer vs. winter and effluent vs. river) in microbial composition. Microcystis emerged as a crucial species contributing to these variations. Pathogen concentrations were found to be higher in the river than in the effluent, with the winter exhibiting higher concentrations compared to the summer. The effluent discharge slightly increased the pathogen concentrations in the river in summer but dramatically reduced them in winter. The combined effects of cyanobacterial bloom and high temperature were considered key factors suppressing pathogen concentrations in summer. Moreover, the prevalence of antibiotic resistance of pathogens in the river was inferior to that in the effluent, with higher levels in winter than in summer. Three high-concentration pathogens (Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa) were selected for QMRA. The results showed that the risks of pathogens exceeded the recommended threshold value. Escherichia coli posed the highest risks. And the fishing scenario posed significantly higher risks than the walking scenario. Importantly, the effluent discharge helped reduce the microbial risks in the receiving river in winter. The study contributes to the management and decision-making regarding microbial risks in the effluent-receiving river.

Revealing the characteristics of biofilms on different polypropylene plastic products: Comparison between disposable masks and takeaway boxes

The increasingly severe plastic pollution issue was intensified by the enormous plastic emissions into ecosystems during the Covid-19 pandemic. Plastic wastes entering the environment were swiftly exposed to microorganisms and colonized by biofilms, and the plastic-biofilm combined effects further influenced the ecosystem. However, the non-woven structure of disposable masks discarded carelessly during the COVID-19 pandemic was different from those of plastics with flat surface. To reveal the potential effects of plastic structure on colonized biofilms, white disposable surgical masks (DM) and transparent takeaway boxes (TB), both made of polyethylene, were selected for the incubation of organic conditioning films and biofilms. The results indicated that the non-woven structure of disposable mask was destroyed by the influence of water infiltration and biofilm colonization. The influence of surface structure on conditioning films led to a relatively higher proportion of tryptophan-like substances on DM than those on TB samples. Therefore, biofilms with significantly higher microbial biomass and carbon metabolic capacity were formed on DM than those on TB samples owing to the combined effects of their differences in surface structure and conditioning films. Moreover, abundant functional microorganisms associated with stress tolerance, carbon metabolism and biofilm formation were observed in biofilms on disposable mask. Combining with the results of partial least squares regression analysis, the selective colonization of functional microorganisms on disposable masks with uneven surface longitudinal fluctuation was revealed. Although the predicted functions of biofilms on disposable masks and takeaway boxes showed more similarity to each other than to those of free-living aquatic microorganisms owing to the existence of the plastisphere, biofilms on disposable masks may potentially trigger environmental risks different from those of takeaway boxes by unique carbon metabolism and abundant biomass.

Nanofiberous facemasks as protectives against pandemic respiratory viruses

INTRODUCTION

Wearing protective face masks and respirators has been a necessity to reduce the transmission rate of respiratory viruses since the outbreak of the coronavirus (COVID-19) disease. Nevertheless, the outbreak has revealed the need to develop efficient air filter materials and innovative anti-microbial protectives. Nanofibrous facemasks, either loaded with antiviral nanoparticles or not, are very promising personal protective equipment (PPE) against pandemic respiratory viruses.

AREAS COVERED

In this review, multiple types of face masks and respirators are discussed as well as filtration mechanisms of particulates. In this regard, the limitations of traditional face masks were summarized and the advancement of nanotechnology in developing nanofibrous masks and air filters was discussed. Different methods of preparing nanofibers were explained. The various approaches used for enhancing nanofibrous face masks were covered.

EXPERT OPINION

Although wearing conventional face masks can limit viral infection spread to some extent, the world is in great need for more protective face masks. Nanofibers can block viral particles efficiently and can be incorporated into face masks in order to enhance their filtration efficiency. Also, we believe that other modifications such as addition of antiviral nanoparticles can significantly increase the protection power of facemasks.

Ultrathin, ultralight dual-scale fibrous networks with high-infrared transmittance for high-performance, comfortable and sustainable PM0.3 filter

Highly permeable particulate matter (PM) can carry various bacteria, viruses and toxics and pose a serious threat to public health. Nevertheless, current respirators typically sacrifice their thickness and base weight for high-performance filtration, which inevitably causes wearing discomfort and significant consumption of raw materials. Here, we show a facile yet massive splitting eletrospinning strategy to prepare an ultrathin, ultralight and radiative cooling dual-scale fiber membrane with about 80% infrared transmittance for high-protective, comfortable and sustainable air filter. By tailoring antibacterial surfactant-triggered splitting of charged jets, the dual-scale fibrous filter consisting of continuous nanofibers (44 ± 12 nm) and submicron-fibers (159 ± 32 nm) is formed. It presents ultralow thickness (1.49 μm) and base weight (0.57 g m-2) but superior protective performances (about 99.95% PM0.3 removal, durable antibacterial ability) and wearing comfort of low air resistance, high heat dissipation and moisture permeability. Moreover, the ultralight filter can save over 97% polymers than commercial N95 respirator, enabling itself to be sustainable and economical. This work paves the way for designing advanced and sustainable protective materials.

Sports despite masks: no negative effects of FFP2 face masks on cardiopulmonary exercise capacity in children

Face masks were recognized as one of the most effective ways to prevent the spread of the COVID-19 virus in adults. These benefits were extended to children and adolescents. However, the fear of negative consequences from wearing a face mask during physical exercise led to cancellations of physical education lessons. This further decreased the amount of physical activity available to children and adolescents during the pandemic. However, there is little published data on the potential adverse effects of wearing the most effective and partially mandatory FFP2/N95 face masks during PE or physical activity (PA) in this age. Even though the pandemic has been declared as passed by the WHO, the rise of a new pandemic and thus the use of face masks for limiting its spread is inevitable, so we need to be better prepared for alternative options to lockdown and limitation of PA in such a scenario. Twenty healthy children aged 8-10 years performed two identical cardiopulmonary exercise tests as an incremental step test on a treadmill within an interval of 2 weeks, one time without wearing a protective mask and one time wearing an FFP2 mask. The cardiopulmonary exercise parameter and especially the end-expiratory gas exchange for oxygen and carbon dioxide (petO2 and petCO2) were documented for each step, at rest and 1 min after reaching physical exhaustion. Twelve boys (mean age 8.5 ± 1.4 years) and 8 girls (mean age 8.8 ± 1.4 years) showed no adverse events until maximal exertion. The mean parameters measured at peak exercise did not differ significantly between both examinations (mean peak VO2 = 42.7 ± 9.5 vs 47.8 ± 12.9 ml/min/kg, p = 0.097, mean O2pulse 7.84 ± 1.9 ml/min vs. 6.89 ± 1.8, p = 0.064, mean VE/VCO2slope 33.4 ± 5.9 vs. 34.0 ± 5.3, p = 0.689). The only significant difference was the respiratory exchange rate (RER, 1.01 ± 0.08 vs 0.95 ± 0.08, p = 0.004). The measured respiratory gases (end-tidal O2 and CO2) decreased and respectively increased significantly in almost every step when wearing an FFP2 mask. However, these levels were well below hypercapnia and above hypoxia.

CONCLUSION

 In this study, no significant differences in the cardiorespiratory function at peak exercise could be discerned when wearing an FFP2/N95 face mask. While the end-tidal values for CO2 increased significantly and the end-tidal values for O2 decreased significantly, these values did never reach levels of hypercapnia or hypoxia. Furthermore, the children terminated the exercise at a lower RER and heart rate (HR) suggesting a subconscious awareness of the higher strain. Since the detrimental effects of limiting sports during the pandemic are well documented, stopping PE lessons altogether because of the minor physiological effects of wearing these masks instead of simply stopping pushing children to perform at their best seems premature and should be reconsidered in the future.

WHAT IS KNOWN

• Wearing a face mask has an influence on psychological, social, and physiological functions in adults. • Because of the observed effects of wearing face masks in adults, physical activity in children was limited during the pandemic.

WHAT IS NEW

• Wearing an FFP2/N95 mask during physical activity did not lead to hypercapnia or hypoxia in children in this study. • Even though end-tidal CO2 values were significantly higher and end-tidal O2 values significantly lower when wearing an FFP2/N95 face mask, no pathological values were reached.

Biosurfactant-capped CuO nanoparticles coated cotton/polypropylene fabrics toward antimicrobial textile applications

The global COVID-19 pandemic has led to an increase in the importance of implementing effective measures to prevent the spread of microorganisms. Consequently, there is a growing demand for antimicrobial materials, specifically antimicrobial textiles and face masks, because of the surge in diseases caused by bacteria and viruses like SARS-CoV-2. Face masks that possess built-in antibacterial properties can rapidly deactivate microorganisms, enabling reuse and reducing the incidence of illnesses. Among the numerous types of inorganic nanomaterials, copper oxide nanoparticles (CuO NPs) have been identified as cost-effective and highly efficient antimicrobial agents for inactivating microbes. Furthermore, biosurfactants have recently been recognized for their potential antimicrobial effects, in addition to inorganic nanoparticles. Therefore, this research's primary focus is synthesizing biosurfactant-mediated CuO NPs, integrating them into natural and synthetic fabrics such as cotton and polypropylene and evaluating the resulting fabrics' antimicrobial activity. Using rhamnolipid (RL) as a biosurfactant and employing a hydrothermal method with a pH range of 9-11, RL-capped CuO NPs are synthesized (RL-CuO NPs). To assess their effectiveness against gram-positive (Staphylococcus aureus) and gram-negative (Escherichia coli) microorganisms, the RL-CuO NPs are subjected to antibacterial testing. The RL-capped CuO NPs exhibited antimicrobial activity at much lower concentrations than the individual RL, CuO. RL-CuO NPs have shown a minimum inhibitory concentration (MIC) of 1.2 mg ml-1and minimum bactericidal concentration (MBC) of 1.6 mg ml-1forE. coliand a MIC of 0.8 mg ml-1and a MBC of 1.2 mg ml-1forS. aureus, respectively. Furthermore, the developed RL-CuO NPs are incorporated into cotton and polypropylene fabrics using a screen-printing technique. Subsequently, the antimicrobial activity of the coated fabrics is evaluated, revealing that RL-CuO NPs coated fabrics exhibited remarkable antibacterial properties against both gram-positive and gram-negative bacteria.

Polarity-dominated chitosan biguanide hydrochloride-based nanofibrous membrane with antibacterial activity for long-lasting air filtration

Facemasks play a significant role as personal protective equipment during the COVID-19 pandemic, but their longevity is limited by the easy dissipation of electrostatic charge and the accumulation of bacteria. In this study, nanofibrous membranes composed of polyacrylonitrile and chitosan biguanide hydrochloride (PAN@CGH) with remarkable antibacterial characteristics were prepared through the coaxial electrospinning process. Particulate matter could be efficiently captured by the fibrous membrane, up to 98 % or more, via polarity-dominated forces derived from cyano and amino groups. As compared commercial N95 masks, the PAN@CGH was more resistant to a wider variety of disinfection protocols. Additionally, the nanofibrous membrane could kill >99.99 % of both Escherichia coli and Staphylococcus aureus. Based on these characteristics, PAN@CGH nanofibrous membrane was applied to facial mask, which possessed an excellent and long-lasting effect on the capture of airborne particles. This work may be one of the most promising strategies on designing high-performance face masks for public health protection.

The Usability of Face Coverings Used to Prevent the Spread of COVID-19

OBJECTIVE

To describe the perceived usability and usability problems associated with face coverings used to prevent the spread of COVID-19.

BACKGROUND

Since public health experts have now identified the appropriate use of facemasks as one of the critical elements in an effective COVID mitigation strategy, understanding how people use and care for them has become important.

METHOD

Data were collected via a survey that was shared on social media to which 2148 people responded. Participants were asked to identify the category class of the face covering they most often wear, rate its usability, answer demographic information, and questions about their mask use and hygiene, and identify issues they may suffer in relation to face cover use.

RESULTS

Overall, users appear to perceive their face coverings favorably from a usability and satisfaction standpoint, even though almost two-thirds of users indicated that they experienced discomfort and problems with glasses fogging with the most popular mask types. When considering demographic information, users' political party affiliation appears related to how they perceive the usability of their face covering.

CONCLUSION

Designers should work to improve the fit and comfort properties of protective masks; evidence suggests the System Usability Scale may be a useful tool in those efforts.

APPLICATION

Understanding mask design and behavioral issues related to their use can help in the development of masks and will maximize their acceptance and effectiveness in the field.

A Fiber Sliding-Orientation Based Micromechanics Failure Model for Melt-Blown Nonwovens

The mechanical model of melt-blown nonwovens (MNs) serves as the foundation for performance optimization, which can offer helpful guidance for product material selection, structural design, and cost control. However, it is challenging to describe the micromechanics failure mechanism of MNs using the traditional mechanical model, which aims to match the model curve with the experimental result at the macrolevel. Herein, a micromechanics failure model for MNs based on sliding-orientation competition is developed. Through in situ observations of fiber position changes and the fluctuation of stress-strain curves, fiber sliding and orientation are introduced into the failure process of MNs. Due to fiber bonding and static friction, only orientation happens during the first stage of stretching. In dramatic contrast, the fibers will slide and orient in the second stage of stretching to change their positions in response to the external force. Sliding friction, fiber bonding, and static friction make up the stress of MNs, and the conflict of fiber sliding and orientation causes variations in the stress. The model has been successfully applied to polylactic acid (PLA) MNs, which proves the effectiveness of the model in MNs.

Antiviral activity of salt-coated materials against SARS-CoV-2

The SARS-CoV-2 pandemic demonstrated the importance of human coronaviruses and the need to develop materials to prevent the spread of emergent respiratory viruses. Coating of surfaces with antiviral materials is a major interest in controlling spread of viruses, especially in high-risk or high-traffic areas. A number of different coatings for surfaces have been proposed, each with their own advantages and disadvantages. Here we show that simple salt coating on a range of surfaces, including a novel biomass aerogel can reduce the infectivity of SARS-CoV-2 placed onto the surface. This suggests that a simple to apply coating could be applied to a range of materials and have an antiviral effect against SARS-CoV-2, as well as other potential emerging viruses.

Personal protective equipment-derived pollution during Covid-19 era: A critical review of ecotoxicology impacts, intervention strategies, and future challenges

During the COVID-19 pandemic, people used personal protective equipment (PPE) to lessen the spread of the virus. The release of microplastics (MPs) from discarded PPE is a new threat to the long-term health of the environment and poses challenges that are not yet clear. PPE-derived MPs have been found in multi-environmental compartments, e.g., water, sediments, air, and soil across the Bay of Bengal (BoB). As COVID-19 spreads, healthcare facilities use more plastic PPE, polluting aquatic ecosystems. Excessive PPE use releases MPs into the ecosystem, which aquatic organisms ingest, distressing the food chain and possibly causing ongoing health problems in humans. Thus, post-COVID-19 sustainability depends on proper intervention strategies for PPE waste, which have received scholarly interest. Although many studies have investigated PPE-induced MPs pollution in the BoB countries (e.g., India, Bangladesh, Sri Lanka, and Myanmar), the ecotoxicity impacts, intervention strategies, and future challenges of PPE-derived waste have largely gone unnoticed. Our study presents a critical literature review covering the ecotoxicity impacts, intervention strategies, and future challenges across the BoB countries (e.g., India (162,034.45 tons), Bangladesh (67,996 tons), Sri Lanka (35,707.95 tons), and Myanmar (22,593.5 tons). The ecotoxicity impacts of PPE-derived MPs on human health and other environmental compartments are critically addressed. The review's findings infer a gap in the 5R (Reduce, Reuse, Recycle, Redesign, and Restructure) Strategy's implementation in the BoB coastal regions, hindering the achievement of UN SDG-12. Despite widespread research advancements in the BoB, many questions about PPE-derived MPs pollution from the perspective of the COVID-19 era still need to be answered. In response to the post-COVID-19 environmental remediation concerns, this study highlights the present research gaps and suggests new research directions considering the current MPs' research advancements on COVID-related PPE waste. Finally, the review suggests a framework for proper intervention strategies for reducing and monitoring PPE-derived MPs pollution in the BoB countries.

The Influence of COVID-19 in Endocrine Research: Critical Overview, Methodological Implications and a Guideline for Future Designs

The COVID-19 pandemic has changed many aspects of people's lives, including not only individual social behavior, healthcare procedures, and altered physiological and pathophysiological responses. As a result, some medical studies may be influenced by one or more hidden factors brought about by the COVID-19 pandemic. Using the literature review method, we are briefly discussing the studies that are confounded by COVID-19 and facemask-induced partiality and how these factors can be further complicated with other confounding variables. Facemask wearing has been reported to produce partiality in studies of ophthalmology (particularly dry eye and related ocular diseases), sleep studies, cognitive studies (such as emotion-recognition accuracy research, etc.), and gender-influenced studies, to mention a few. There is a possibility that some other COVID-19 related influences remain unrecognized in medical research. To account for heterogeneity, current and future studies need to consider the severity of the initial illness (such as diabetes, other endocrine disorders), and COVID-19 infection, the timing of analysis, or the presence of a control group. Face mask-induced influences may confound the results of diabetes studies in many ways.

Current perspectives of metal-based nanomaterials as photocatalytic antimicrobial agents and their therapeutic modes of action: A review

Efforts to restrict the emergence and progression of multidrug-resistant bacterial strains should heavily involve the scientific community, including government bodies, researchers, and industries, in developing new and effective photocatalytic antimicrobial agents. Such changes warrant the modernization and upscaling of materials synthesis laboratories to support and expedite the mass production of materials at the industrial scale for the benefit of humankind and the environment. Despite the massive volume of publications reporting the potential usage of different types of metal-based nanomaterials as antimicrobial agents, reviews uncovering the similarities and differences among the various products remain lacking. This review details the basic and unique properties of metal-based nanoparticles, their use as photocatalytic antimicrobial agents, and their therapeutic modes of action. It shall be noted that compared to traditional antibiotics, the mode of action of photocatalytic metal-based nanomaterials for killing microorganisms are completely different, despite displaying promising performance against antibiotic-resistant bacteria. Besides, this review uncovers the differences in the mode of actions of metal oxide nanoparticles against different types of bacteria, as well as towards viruses. Last but not least, this review comprehensively describes previous published clinical trials and medical usages involving contemporary photocatalytic antimicrobial agents.

Determining the filtration effectiveness of non-standard respiratory protective devices by an ad-hoc laboratory methodology

The recent pandemic caused by COVID-19 profoundly changed people's habits. Wearing a face mask has become usual in everyday life to reduce the risk of infection from airborne diseases. At the beginning of the pandemic, the massive request of surgical or filtering face piece (FFP) masks resulted in a global shortage of these devices for the most exposed people, such as healthcare workers. Due to this high demand for respiratory protective devices, many industrial plants have partly converted to the production of face masks using adapted materials and not complying with any specific regulation (non-standard respiratory protective devices or community masks). In this work, an ad-hoc laboratory methodology has been developed to evaluate the filtration efficiency of the materials that compose the community masks using specific instrumentation. The instrumentation consists of three main tools: an aerosol generator, a specifically designed measuring chamber, and an optical particle sizer (OPS) for the measurement of aerosol concentration. The generated aerosol was sent into the measuring chamber, divided into two separate sections by the respiratory mask. The OPS measured the aerosol mass concentration upstream and downstream of the respiratory mask, and from the concentration difference the filtration efficiency was evaluated. The proposed methodology has been validated by evaluating the particle filtration efficiency (PFE) of certified respiratory masks and was then applied for the evaluation of the filtration efficiency of different types of non-standard or community masks to analyze their effectiveness in protecting from the risk of infection of airborne diseases.

Biomedical waste plastic: bacteria, disinfection and recycling technologies-a comprehensive review

Plastic recycling reduces the wastage of potentially useful materials as well as the consumption of virgin materials, thereby lowering the energy consumption, air pollution by incineration, soil and water pollution by landfilling. Plastics used in the biomedical sector have played a significant role. Reducing the transmission of the virus while protecting the human life in particular the frontline workers. Enormous volumes of plastics in biomedical waste have been observed during the outbreak of the pandemic COVID-19. This has resulted from the extensive use of personal protective equipment such as masks, gloves, face shields, bottles, sanitizers, gowns, and other medical plastics which has created challenges to the existing waste management system in the developing countries. The current review focuses on the biomedical waste and its classification, disinfection, and recycling technology of different types of plastics waste generated in the sector and their corresponding approaches toward end-of-life option and value addition. This review provides a broader overview of the process to reduce the volume of plastics from biomedical waste directly entering the landfill while providing a knowledge step toward the conversion of "waste" to "wealth." An average of 25% of the recyclable plastics are present in biomedical waste. All the processes discussed in this article accounts for cleaner techniques and a sustainable approach to the treatment of biomedical waste.

Graphical abstract

Different weathering conditions affect the release of microplastics by masks

A generation of microplastics caused by improper disposal of disposable masks has become a non-negligible environmental concern. In order to investigate the degradation mechanisms of masks and the release of microplastics under different environmental conditions, the masks are placed in 4 common environments. After 30 days of weathering, the total amount and release kinetics of microplastics released from different layers of the mask were studied. The chemical and mechanical properties of the mask were also discussed. The results showed that the mask released 25141±3543 particles/mask into the soil, which is much more than the sea and river water. The release kinetics of microplastics fit the Elovich model better. All samples correspond to the release rate of microplastics from fast to slow. Experiments show that the middle layer of the mask is released more than the other layers, and the amount of release was highest in the soil. And the tensile capacity of the mask is negatively correlated with its ability to release microplastics in the following order, which are soil > seawater > river > air > new masks. In addition, during the weathering process, the C-C/C-H bond of the mask was broken.

Advanced and Smart Textiles during and after the COVID-19 Pandemic: Issues, Challenges, and Innovations

The COVID-19 pandemic has hugely affected the textile and apparel industry. Besides the negative impact due to supply chain disruptions, drop in demand, liquidity problems, and overstocking, this pandemic was found to be a window of opportunity since it accelerated the ongoing digitalization trends and the use of functional materials in the textile industry. This review paper covers the development of smart and advanced textiles that emerged as a response to the outbreak of SARS-CoV-2. We extensively cover the advancements in developing smart textiles that enable monitoring and sensing through electrospun nanofibers and nanogenerators. Additionally, we focus on improving medical textiles mainly through enhanced antiviral capabilities, which play a crucial role in pandemic prevention, protection, and control. We summarize the challenges that arise from personal protective equipment (PPE) disposal and finally give an overview of new smart textile-based products that emerged in the markets related to the control and spread reduction of SARS-CoV-2.

Shape Memory Respirator Mask for Airborne Viruses

The emergence of COVID-19 has spurred demand for facemasks and prompted many studies aiming to develop masks that provide maximum protection. Filtration capacity and fit define the level of protection a mask can provide, and the fit is in large part determined by face shape and size. Due to differences in face dimensions and shapes, a mask of one size will not be likely to fit all faces. In this work, we examined shape memory polymers (SMPs) for producing facemasks that are able to alter their shape and size to fit every face. Polymer blends with and without additives or compatibilizers were melt-extruded, and their morphology, melting and crystallization behavior, mechanical properties, and shape memory (SM) behavior were characterized. All the blends had phase-separated morphology. The mechanical properties of the SMPs were modified by altering the content of polymers and compatibilizers or additives in the blends. The reversible and fixing phases are determined by the melting transitions. SM behavior is caused by physical interaction at the interface between the two phases in the blend and the crystallization of the reversible phase. The optimal SM blend and printing material for the mask was determined to be a polylactic acid (PLA)/polycaprolactone (PCL) blend with 30% PCL. A 3D-printed respirator mask was manufactured and fitted to several faces after being thermally activated at 65°C. The mask had excellent SM and could be molded and remolded to fit a variety of facial shapes and sizes. The mask also exhibited self-healing and healed from surface scratches.

COVID-19 clinical waste reuse: A triboelectric touch sensor for IoT-cloud supported smart hand sanitizer dispenser

Earth's plastic pollution has increased due to the COVID-19 pandemic, and the world is on the doorstep of an enormous waste pandemic. The extensive use of mandatory personal protectives like masks, gloves, and PPE kits and the lack of proper waste management systems lead to a rise in the plastic pollution content of the earth. Such disposable and non-biodegradable personal protectives are thrown out to the environment after use. These distributed wastes pollute land, soil, and water bodies and effects their ecosystems. This research work establishes the concept of a waste-to-energy conversion approach to reuse COVID-19 scraps for green and sustainable development. Three-layered surgical masks and nitrile gloves were reused in this work after sterilization for energy harvesting and sensing applications by fabricating a 3D-printed contact-separation-based triboelectric nanogenerator. A piece of three-layered mask and nitrile gloves were placed inside the 3D structure as the top negative and bottom positive triboelectric materials with copper and aluminum as corresponding electrodes (MG-CS TENG). It can convert external mechanical motions into electrical energy. The maximum voltage, current, and power density obtained from the device are 50.7 V, 4.8 µA, and 6.39 µW/cm², respectively, for a mechanical force of 9 N. The harvested energy was sufficient to power small-scale electronic devices like digital tally counters, wristwatches, lumex displays, and series connected 25 LEDs. MG-CS TENG was also performed as a pedal-operated touch sensor to dispense hand sanitizer. MG-CS TENG was pedal pressed to trigger a microcontroller and control the solenoid valve's opening and closing to regulate sanitizer flow. The setup was integrated using the internet of things (IoT) and Blynk cloud services for the remote monitoring and controlling of the sanitizer dispenser using a smartphone. This work contributes a substantial role in disaster management to suppress microplastic environmental pollution by reusing pandemic wastes for energy harvesting and sensing applications and preventing the spread of coronavirus through proper hand sanitization.

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.

Antimicrobial Nanomaterials as Advanced Coatings for Self-Sanitizing of Textile Clothing and Personal Protective Equipment

Controlling bioaerosols has become increasingly critical in affecting human health. Natural product treatment in the nano form is a potential method since it has lower toxicity than inorganic nanomaterials like silver nanoparticles. This research is important for the creation of a bioaerosol control system that is effective. Nanoparticles (NPs) are gradually being employed to use bacteria as a nonantibiotic substitute for treating bacterial infections. The present study looks at nanoparticles' antimicrobial properties, their method of action, their impact on drug-opposing bacteria, and the hazards connected with their operation as antimicrobial agents. The aspects that influence nanoparticle conduct in clinical settings, as well as their distinctive features and mode of action as antibacterial assistants, are thoroughly examined. Nanoparticles' action on bacterial cells is presently accepted by way of the introduction of oxidative stress induction, metal-ion release, and nonoxidative methods. Because many concurrent mechanisms of action against germs would necessitate multiple simultaneous gene modifications in the same bacterial cell for antibacterial protection to evolve, bacterial cells developing resistance to NPs is difficult. This review discusses the antimicrobial function of NPs against microbes and presents a comprehensive discussion of the bioaerosols: their origin, hazards, and their prevention. This state of the art method is dependent upon the use of personal protective gear against these bioaerosols. The benefit of the utmost significant categories of metal nanoparticles as antibacterial agents is given important consideration. The novelty of this review depends upon the antimicrobial properties of (a) silver (Ag), (b) zinc oxide (ZnO), and (c) copper oxide (CuO) nanoparticles. The value-added features of these nanoparticles are discussed, as well as their physicochemical characterization and pharmacokinetics, including the toxicological danger they pose to people. Lastly, the effective role of nanomaterials and their future in human wellness is discussed.

Development of a reusable low-cost facemask with a recycled hydrophobic layer for preventive health care

The current work focuses on designing a low-cost, reusable, and highly efficient facemask for protection from respiratory droplets that cause COVID-19, other infection-causing organisms, and dust allergies. Several masks available in the market are single-use that would choke the environment through plastic pollution or are expensive for the commoner to afford. In the present study, the facemask incorporates a waste-derived polyethylene terephthalate (PET) layer and a non-woven polypropylene (PP) layer sandwiched between two tightly woven cotton layers. Combining these layers provides comfort and breathability, besides high bacterial and particulate filtration efficiency. Moreover, the unique PET layer provides mechanical strength and a 3D shape that enables hindrance-free speaking and prevents spectacle fogging. Compared to commercial N95 masks, the developed mask can be reused up to 30 washes and recycled with zero waste discharge ensuing green technology. Moreover, the mask was produced at an affordable cost of Rs. 17 (0.22 USD), including labor charges, and sold at a 100% profit margin @ Rs.35 (0.45 USD) per unit. Further, the mask was certified by neutral testing agencies and provided to a population of more than 6 lakhs, thus significantly contributing to the mitigation of COVID-19.

Facemask: Protection or threat?

Facemasks were widely used as a protection against SARS-COV-2, which significantly reduced COVID-19 transmission during the pandemic. However, concerns have been raised regarding its adverse impacts on human health due to intense use and mismanagement. Although rampant plastic littering was the norm before the pandemic, the magnitude of the problem is worsening as potentially COVID-19-infected facemasks are thrown along the shoreline. This study assessed the discarded facemasks on the most popular beach destinations in Mati City, Davao Oriental, Philippines. A total of N = 284 discarded facemasks were found in a cumulative area of 22,500 m², with an average density of 8.4 × 10^-4 items/m². The surgical facemask (82 %; n = 234) was the most abundant type of facemask found in the areas, followed by KF94 (16 %; n = 45) and KN95 (2 %; n = 5). The Analysis of Variance (ANOVA) showed significant differences in the visual counts of facemasks on the three beaches (p < 0.05).

Fighting the Pandemic with "Shields": Successful COVID-19 Securitization and Mask Policy in Taiwan

Facemasks have been proven an effective non-pharmaceutical measure against coronavirus disease-19. Against the backdrop of global mask shortages, Taiwan distinguished herself from other countries in that Taiwan took a whole-of-nation approach to masks and mobilized the society quickly to become self-sufficient in masks. This paper argues that successful virus securitization as a threat to national security was what enabled Taiwan to effectively mobilize the private sector to carry out the state's will in ensuring adequate mask supply. Moreover, Taiwan securitized the virus more successfully than many other countries because the virus was connected to China, the nation's existing security threat.

Exudation of microplastics from commonly used face masks in COVID-19 pandemic

The COVID-19 pandemic forced use of face masks up to billions of masks per day globally. Though an important and necessary measure for control of the pandemic, use of masks also poses some inherent risks. One of those risks is inhalation of microplastics released from the mask materials. Since most of the mask materials are made from plastic/polymers, they always have the potential to expose the user to fragmented microplastics. To estimate the amount of inhalable microplastic exuded from masks, an experiment simulating real-life scenario of mask usage was performed. The study included collection of microplastics oozed out from the masks on to a filter paper followed by staining and fluorescence detection of the total number of microplastics using a microscope. Both used and new masks were studied. Based on the emission wavelength, the microplastics were found to be belonging to three different categories, namely blue, green and red emitting microplastics respectively. The number of microplastic particles emitted per mask over a period of usage of 8 h was about 5000 to 9000 for new masks and about 6500 to 15,000 for used masks respectively. The estimation of polymer type of plastic in the mask fabrics was also carried out using Raman and FTIR spectroscopy.

Targeting viral proteins for restraining SARS-CoV-2: focusing lens on viral proteins beyond spike for discovering new drug targets

INTRODUCTION

Emergence of highly infectious SARS-CoV-2 variants are reducing protection provided by current vaccines, requiring constant updates in antiviral approaches. The virus encodes four structural and sixteen nonstructural proteins which play important roles in viral genome replication and transcription, virion assembly, release , entry into cells, and compromising host cellular defenses. As alien proteins to host cells, many viral proteins represent potential targets for combating the SARS-CoV-2.

AREAS COVERED

Based on literature from PubMed and Web of Science databases, the authors summarize the typical characteristics of SARS-CoV-2 from the whole viral particle to the individual viral proteins and their corresponding functions in virus life cycle. The authors also discuss the potential and emerging targeted interventions to curb virus replication and spread in detail to provide unique insights into SARS-CoV-2 infection and countermeasures against it.

EXPERT OPINION

Our comprehensive analysis highlights the rationale to focus on non-spike viral proteins that are less mutated but have important functions. Examples of this include: structural proteins (e.g. nucleocapsid protein, envelope protein) and extensively-concerned nonstructural proteins (e.g. NSP3, NSP5, NSP12) along with the ones with relatively less attention (e.g. NSP1, NSP10, NSP14 and NSP16), for developing novel drugs to overcome resistance of SARS-CoV-2 variants to preexisting vaccines and antibody-based treatments.

Personal protective equipment (PPE) disposal during COVID-19: An emerging source of microplastic and microfiber pollution in the environment

Waste generated by healthcare facilities during the COVID-19 pandemic has become a new source of pollution, particularly with the widespread use of single-use personal protective equipment (PPE). Releasing microplastics (MPs) and microfibers (MFs) from discarded PPE becomes an emerging threat to environmental sustainability. MPs/MFs have recently been reported in a variety of aquatic and terrestrial ecosystems, including water, deep-sea sediments, air, and soil. As COVID-19 spreads, the use of plastic-made PPE in healthcare facilities has increased significantly worldwide, resulting in massive amounts of plastic waste entering the terrestrial and marine environments. High loads of MPs/MFs emitted into the environment due to excessive PPE consumption are easily consumed by aquatic organisms, disrupting the food chain, and potentially causing chronic health problems in humans. Thus, proper management of PPE waste is critical for ensuring a post-COVID sustainable environment, which has recently attracted the attention of the scientific community. The current study aims to review the global consumption and sustainable management of discarded PPE in the context of COVID-19. The severe impacts of PPE-emitted MPs/MFs on human health and other environmental segments are briefly addressed. Despite extensive research progress in the area, many questions about MP/MF contamination in the context of COVID-19 remain unanswered. Therefore, in response to the post-COVID environmental remediation concerns, future research directions and recommendations are highlighted considering the current MP/MF research progress from COVID-related PPE waste.

Functional Textile Materials for Blocking COVID-19 Transmission

The outbreak of COVID-19 provided a warning sign for society worldwide: that is, we urgently need to explore effective strategies for combating unpredictable viral pandemics. Protective textiles such as surgery masks have played an important role in the mitigation of the COVID-19 pandemic, while revealing serious challenges in terms of supply, cross-infection risk, and environmental pollution. In this context, textiles with an antivirus functionality have attracted increasing attention, and many innovative proposals with exciting commercial possibilities have been reported over the past three years. In this review, we illustrate the progress of textile filtration for pandemics and summarize the recent development of antiviral textiles for personal protective purposes by cataloging them into three classes: metal-based, carbon-based, and polymer-based materials. We focused on the preparation routes of emerging antiviral textiles, providing a forward-looking perspective on their opportunities and challenges, to evaluate their efficacy, scale up their manufacturing processes, and expand their high-volume applications. Based on this review, we conclude that ideal antiviral textiles are characterized by a high filtration efficiency, reliable antiviral effect, long storage life, and recyclability. The expected manufacturing processes should be economically feasible, scalable, and quickly responsive.

Carbon footprint assessment of face masks in the context of the COVID-19 pandemic: Based on different protective performance and applicable scenarios

Widespread concerns have been raised about the huge environmental burden caused by massive consumption of face masks in the context of the COVID-19 pandemic. However, most of the existing studies only focus on the environmental impact associated with the product itself regardless of the actual usage scenarios and protective performance of products, resulting in unrealistic conclusions and poor applicability. In this context, this study integrated the product performance into the existing carbon footprint assessment methodology, with focus on the current global concerns regarding climate change. Computational case studies were conducted for different mask products applicable to the scenarios of low-, medium- and high-risk levels. The results showed that reusable cotton masks and disposable medical masks suitable for low-risk settings have a total carbon footprint of 285.484 kgCO₂-eq/FU and 128.926 kgCO₂-eq/FU respectively, with a break-even point of environmental performance between them of 16.886, which implies that cotton masks will reverse the trend and become more environmentally friendly after 17 washes, emphasizing the importance of improving the washability of cotton masks. Additionally, the total carbon footprints of disposable surgical masks and KN95 respirators were 154.328 kg CO₂-eq/FU and 641.249 kg CO₂-eq/FU respectively, while disposable medical masks and disposable surgical masks were identified as alternatives with better environmental performance in terms of medium- and high-risk environments respectively. The whole-life-cycle oriented carbon footprint evaluation further indicated that the four masks have greater potential for carbon emission reduction in the raw material processing and production processes. The results obtained in this study can provide scientific guidance for manufacturers and consumers on the production and use of protective masks. Moreover, the proposed model can be applied to other personal protective equipment with similar properties, such as protective clothing, in the future.

Energy-saving COVID-19 biomedical plastic waste treatment using the thermal - Catalytic pyrolysis

The rate of Biomedical waste generation increases exponentially during infectious diseases, such as the SARS-CoV-2 virus, which burst in December 2019 and spread worldwide in a very short time, causing over 6 M casualties worldwide till May 2022. As per the WHO guidelines, the facemask has been used by every person to prevent the infection of the SARS-CoV-2 virus and discarded as biomedical waste. In the present work, a 3-ply facemask was chosen to be treated using the solvent, which was extracted from the different types of waste plastics through the thermal-catalytic pyrolysis process using a novel catalyst. The facemask was dispersed in the solvent in a heating process, followed by dissolution and precipitation of the facemask in the solvent and by filtration of the solid facemask residue out of the solvent. The effect of peak temperature, heating rate, and type of solvent is observed experimentally, and it found that the facemask was dissolved completely with a clear supernate in the solvent extracted from the (polypropylene + poly-ethylene) plastic also saved energy, while the solvent from ABS plastic was not capable to dissolute the facemask. The potential of the presented approach on the global level is also examined.

Extending the Protection Ability and Life Cycle of Medical Masks through the Washing Process

The reuse of decontaminated disposable medical face masks can contribute to reducing the environmental burden of discarded masks. This research is focused on the effect of household and laboratory washing at 50 °C on the quality and functionality of the nonwoven structure of polypropylene medical masks by varying the washing procedure, bath composition, disinfectant agent, and number of washing cycles as a basis for reusability. The barrier properties of the medical mask were analyzed before and after the first and fifth washing cycle indirectly by measuring the contact angle of the liquid droplets with the front and back surface of the mask, further by measuring air permeability and determining antimicrobial resistance. Additional analysis included FTIR, pH of the material surface and aqueous extract, as well as the determination of residual substances-surfactants-in the aqueous extract of washed versus unwashed medical masks, while their aesthetic aspect was examined by measuring their spectral characteristics. The results showed that household washing had a stronger impact on the change of some functional properties, primarily air permeability, than laboratory washing. The addition of the disinfectant agent, didecyldimethylammonium chloride, contributes to the protective ability and supports the idea that washing of medical masks under controlled conditions can preserve barrier properties and enable reusability.

Size-specific filtration efficiency and pressure drop of school-aged children's woven and nonwoven masks at varying face velocities

BACKGROUND

Differences in physiology and breathing patterns between children and adults lead to disparate responses to aerosols of varying sizes. No standardized method exists for measuring the filtration efficiency (FE) of children's masks to reflect such differences.

METHODS

Using an adult N95 mask as a control and two different face velocities (v_f) (9.3 cm/s representing adults and 4.0 cm/s representing school-aged children), we tested the pressure drop (ΔP) through children's nonwoven masks (surgical and KN95) and children's woven masks (100% cotton and partially-cotton-based masks), as well as their size-specific FE between aerodynamic particle diameters of 0.02 and 2.01 μm.

RESULTS

All three types of mask showed a 1 to 9% absolute increase in minimum FE at the lower v_f and a significant decrease in ΔP. For children's surgical masks the increase in FE was significant for most of the examined particle sizes, but for children's woven masks the increase was limited to particles smaller than 0.04 μm.

CONCLUSIONS

Lower v_f for children is likely to lead to a higher FE, lower ΔP, and consequently higher filter qualities in children's masks. For woven masks, the FE for particles larger than 0.04 μm was low (typically <50%) for both v_f's studied.

Fabrication of silver nanoparticles-deposited fabrics as a potential candidate for the development of reusable facemasks and evaluation of their performance

Recently, wearing facemasks in public has been raised due to the coronavirus disease 2019 epidemic worldwide. However, the performance and effectiveness of many existing products have raised significant concerns among people and professionals. Therefore, greater attempts have been focused recently to increase the efficacy of these products scientifically and industrially. In this respect, doping or impregnating facemask fabrics with metallic substances or nanoparticles like silver nanoparticles has been proposed. So, in the present study, we aimed to sonochemically coat silver nanoparticles on the non-woven Spunbond substrates at different sonication times and concentrations to develop antibacterial and antiviral facemask. The coated substrates were characterized using Field Emission Scanning Electron Microscope, Energy Dispersive X-Ray, X-ray diffraction, and Thermogravimetry analysis. The amount of silver released from the coated substrates was measured by atomic absorption spectroscopy. The filtration efficiency, pressure drop, and electrical conductivity of the coated samples were also investigated. The antibacterial activity of fabrics was evaluated against Escherichia coli and Staphylococcus aureus. Cellular viability of samples assessed by MTT and brine shrimp lethality tests. The results revealed that the higher sonication times and precursor concentrations result in a higher and more stable coating, larger particle size, wider particle size distribution, and lower content of released silver. Coated fabrics also revealed enhanced filtration efficiency (against nanosize particles), desired pressure drop, and antibacterial activity without significant cytotoxicity toward HEK 293 cells and Artemia nauplii. As a result, the coated fabrics could find potential applications in the development of facemasks for protection against different pathogenic entities.

Bio-Polypropylene and Polypropylene-based Biocomposites: Solutions for a Sustainable Future

Polypropylene (PP) is among the most widely used commodity plastics in our everyday life due to its low cost, lightweight, easy processability, and exceptional chemical, thermo-mechanical characteristics. The growing awareness on energy and environmental crisis has driven global efforts for creating a circular economy via developing sustainable and eco-friendly alternatives to traditional plastics produced from fossil fuels for a variety of end-use applications. This review paper presents a brief outline of the emerging bio-based PP derived from renewable natural resources, covering its production routes, market analysis and potential utilizations. This contribution also provides a comprehensive review of the PP-based biocomposites produced with diverse green fillers generated from agro-industrial wastes, with particular emphasis on the structural modification, processing techniques, mechanical properties, and practical applications. Furthermore, given that the majority of PP products are currently destined for landfills, research progress on enhancing the degradation of PP and its biocomposites is also presented in light of the environmental concerns. Finally, a brief conclusion with discussions on challenges and future perspectives are provided.

A review on enhanced microplastics derived from biomedical waste during the COVID-19 pandemic with its toxicity, health risks, and biomarkers

The COVID-19 pandemic led to the explosion of biomedical waste, a global challenge to public health and the environment. Biomedical waste comprising plastic can convert into microplastics (MPs, < 5 mm) by sunlight, wave, oxidative and thermal processes, and biodegradation. MPs with additives and contaminants such as metals are also hazardous to many aquatic and terrestrial organisms, including humans. Bioaccumulation of MPs in organisms often transfers across the trophic level in the global food web. Thus, this article aims to provide a literature review on the source, quantity, and fate of biomedical waste, along with the recent surge of MPs and their adverse impact on aquatic and terrestrial organisms. MPs intake (ingestion, inhalation, and dermal contact) in humans causing various chronic diseases involving multiple organs in digestive, respiratory, and reproductive systems are surveyed, which have been reviewed barely. There is an urgent need to control and manage biomedical waste to shrink MPs pollution for reducing environmental and human health risks.

Plasma degradation of contaminated PPE: an energy-efficient method to treat contaminated plastic waste

The use of PPE has drastically increased because of the SARS-CoV-2 (COVID-19) pandemic as disposable surgical face masks made from non-biodegradable polypropylene (PP) polymers have generated a significant amount of waste. In this work, a low-power plasma method has been used to degrade surgical masks. Several analytical techniques (gravimetric analysis, scanning electron microscopy (SEM), attenuated total reflection-infra-red spectroscopy (ATR-IR), x-ray photoelectron spectroscopy (XPS), thermogravimetric analysis/differential scanning calorimetry (TGA/DSC) and wide-angle x-ray scattering (WAXS)) were used to evaluate the effects of plasma irradiation on mask samples. After 4 h of irradiation, an overall mass loss of 63 ± 8%, through oxidation followed by fragmentation, was observed on the non-woven 3-ply surgical mask, which is 20 times faster than degrading a bulk PP sample. Individual components of the mask also showed different degradation rates. Air plasma clearly represents an energy-efficient tool for treating contaminated PPE in an environmentally friendly approach.

Environmental challenges of COVID-19 pandemic: resilience and sustainability - A review

The emergence of novel respiratory disease (COVID-19) caused by SARS-CoV-2 has become a public health emergency worldwide and perturbed the global economy and ecosystem services. Many studies have reported the presence of SARS-CoV-2 in different environmental compartments, its transmission via environmental routes, and potential environmental challenges posed by the COVID-19 pandemic. None of these studies have comprehensively reviewed the bidirectional relationship between the COVID-19 pandemic and the environment. For the first time, we explored the relationship between the environment and the SARS-CoV-2 virus/COVID-19 and how they affect each other. Supporting evidence presented here clearly demonstrates the presence of SARS-CoV-2 in soil and water, denoting the role of the environment in the COVID-19 transmission process. However, most studies fail to determine if the viral genomes they have discovered are infectious, which could be affected by the environmental factors in which they are found.The potential environmental impact of the pandemic, including water pollution, chemical contamination, increased generation of non-biodegradable waste, and single-use plastics have received the most attention. For the most part, efficient measures have been used to address the current environmental challenges from COVID-19, including using environmentally friendly disinfection technologies and employing measures to reduce the production of plastic wastes, such as the reuse and recycling of plastics. Developing sustainable solutions to counter the environmental challenges posed by the COVID-19 pandemic should be included in national preparedness strategies. In conclusion, combating the pandemic and accomplishing public health goals should be balanced with environmentally sustainable measures, as the two are closely intertwined.

Thermochemical recycling of waste disposable facemasks in a non-electrically powered system

The COVID-19 pandemic encouraged the use of plastic-based personal protective equipment (PPE), which aided greatly in its management. However, the increased production and usage of these PPEs put a strain on the environment, especially in developing and underdeveloped countries. This has led various researchers to study low-cost and effective technologies for the recycling of these materials. One such material is disposable facemasks. However, previous studies have only been able to engage electrically powered reactors for their thermochemical conversion, which is a challenge as these reactors cannot be used in regions with an insufficient supply of electricity. In this study, the authors utilized a biomass-powered reactor for the conversion of waste disposable facemasks and almond leaves into hybrid biochar. The reactor, which is relatively cheap, simple to use, environmentally friendly, and modified for biochar production, is biomass-powered. The co-carbonization process, which lasted 100 min, produced a 46% biochar yield, which is higher than previously obtained biochar yields by other researchers. The biochar thus obtained was characterized to determine its properties. FTIR analysis showed that the biochar contained functional groups such as alkenes, alkynes, hydroxyls, amines, and carbonyls. The EDX analysis revealed that the biochar was primarily made of carbon, tellurium, oxygen, and calcium in the ratios of 57%, 19%, 9%, and 7%, respectively. The inclusion of the facemask decreased the surface area and porosity of the biochar material, as evidenced by its surface area and pore characteristics.

Type and Duration of Mask Use Related To Acne Vulgaris During The Pandemic Period

The masks' use has been a suggested strategy to counter COVID-19 transmission throughout this disease outbreak; however, wearing masks tightly closed for an extended period can cause acne vulgaris. The mask's form and duration of use are two factors that may affect the occurrence of acne vulgaris. Therefore, more research is needed to determine the impact of using masks on the prevalence of acne vulgaris. This study aimed to analyze the relationship between the type and duration of mask use and the prevalence of acne vulgaris in the citizens of Kawistowindu Village during the pandemic. This study used an analytical-observational study with a cross-sectional approach, with a sample of 63 people who met the inclusion and exclusion criteria throughout the neighborhood of RT.02 RW.01 Kawistowindu Village. The sample was chosen using a simple random sampling technique. Questionnaire forms, history-taking instruments, and physical examination techniques were used to collect data—the analysis used the Chi-Square test. The results showed that during the pandemic era, there was a significant correlation between the type of mask and the duration of mask use with the occurrence of acne vulgaris (p=0.000; p=0.004). In conclusion, in the pandemic era, the mask form and duration of mask use could be linked to acne vulgaris

Stimuli-Activable Metal-Bearing Nanomaterials and Precise On-Demand Antibacterial Strategies

Bacterial infections remain the leading cause of death worldwide today. The emergence of antibiotic resistance has urged the development of alternative antibacterial technologies to complement or replace traditional antibiotic treatments. In this regard, metal nanomaterials have attracted great attention for their controllable antibacterial functions that are less prone to resistance. This review discusses a particular family of stimuli-activable metal-bearing nanomaterials (denoted as SAMNs) and the associated on-demand antibacterial strategies. The various SAMN-enabled antibacterial strategies stem from basic light and magnet activation, with the addition of bacterial microenvironment responsiveness and/or bacteria-targeting selectivity and therefore offer higher spatiotemporal controllability. The discussion focuses on nanomaterial design principles, antibacterial mechanisms, and antibacterial performance, as well as emerging applications that desire on-demand and selective activation (i.e., medical antibacterial treatments, surface anti-biofilm, water disinfection, and wearable antibacterial materials). The review concludes with the authors' perspectives on the challenges and future directions for developing industrial translatable next-generation antibacterial strategies.

Electrospun Filtering Membrane Designed as Component of Self-Decontaminating Protective Masks

The 2019 coronavirus outbreak and worsening air pollution have triggered the search for manufacturing effective protective masks preventing both particulate matter and biohazard absorption through the respiratory tract. Therefore, the design of advanced filtering textiles combining efficient physical barrier properties with antimicrobial properties is more newsworthy than ever. The objective of this work was to produce a filtering electrospun membrane incorporating a biocidal agent that would offer both optimal filtration efficiency and fast deactivation of entrapped viruses and bacteria. After the eco-friendly electrospinning process, polyvinyl alcohol (PVA) nanofibers were stabilized by crosslinking with 1,2,3,4-butanetetracarboxylic acid (BTCA). To compensate their low mechanical properties, nanofiber membranes with variable grammages were directly electrospun on a meltblown polypropylene (PP) support of 30 g/m². The results demonstrated that nanofibers supported on PP with a grammage of around only 2 g/m² presented the best compromise between filtration efficiencies of PM_0.3, PM_0.5, and PM_3.0 and the pressure drop. The filtering electrospun membranes loaded with benzalkonium chloride (ADBAC) as a biocidal agent were successfully tested against E. coli and S. aureus and against human coronavirus strain HCoV-229E. This new biocidal filter based on electrospun nanofibers supported on PP nonwoven fabric could be a promising solution for personal and collective protection in a pandemic context.