A virucidal face mask based on the reverse-flow reactor concept for thermal inactivation of SARS-CoV-2

The Rise of Electroactive Materials in Face Masks for Preventing Virus Infections

Air-transmitted pathogens may cause severe epidemics, posing considerable threats to public health and safety. Wearing a face mask is one of the most effective ways to prevent respiratory virus infection transmission. Especially since the new coronavirus pandemic, electroactive materials have received much attention in antiviral face masks due to their highly efficient antiviral capabilities, flexible structural design, excellent sustainability, and outstanding safety. This review first introduces the mechanism for preventing viral infection or the inactivation of viruses by electroactive materials. Then, the applications of electrostatic-, conductive-, triboelectric-, and microbattery-based materials in face masks are described in detail. Finally, the problems of various electroactive antiviral materials are summarized, and the prospects for their future development directions are discussed. In conclusion, electroactive materials have attracted great attention for antiviral face masks, and this review will provide a reference for materials scientists and engineers in antiviral materials and interfaces.

Rapid In Situ Thermal Decontamination of Wearable Composite Textile Materials

Pandemics stress supply lines and generate shortages of personal protective equipment (PPE), in part because most PPE is single-use and disposable, resulting in a need for constant replenishment to cope with high-volume usage. To better prepare for the next pandemic and to reduce waste associated with disposable PPE, we present a composite textile material capable of thermally decontaminating its surface via Joule heating. This material can achieve high surface temperatures (>100 °C) and inactivate viruses quickly (<5 s of heating), as evidenced experimentally with the surrogate virus HCoV-OC43 and in agreement with analytical modeling for both HCoV-OC43 and SARS-CoV-2. Furthermore, it does not require doffing because it remains relatively cool near the skin (<40 °C). The material can be easily integrated into clothing and provides a rapid, reusable, in situ decontamination method capable of reducing PPE waste and mitigating the risk of supply line disruptions in times of need.

Portable Heating and Temperature-Monitoring System with a Textile Heater Embroidered on the Facemask

Personal heating systems are getting increasing interest because of the need to reduce the negative impact of cold weather on the health of people and animals. Heating the air before inhalation is of great importance as it can reduce the probability of various diseases. In this paper, we present a textile-based heater composed of commercial conductive threads, embroidered on an ordinary protective facemask. We also present the design and implementation details of the temperature monitoring and controlling circuit. Air temperature inside the facemask was monitored by a thermocouple placed in close proximity to the nose (nostrils). Preliminary testing revealed that the difference among temperatures in repeated heating cycles is in the range of ±1.5 °C. The response time for temperature increase from 29.9 to 40.5 °C was about 4 min, while the recovery time from 40.5 to 31.3 °C was about 4.3 min. Safety for human use and wireless data transmission to an application installed on a mobile phone are also demonstrated.

Electrospun nanofiber-based respiratory face masks-a review

The severe acute respiratory syndrome coronavirus (SARS-CoV-2) pandemic of 2019 forced widespread use of face coverings as a mandatory step towards reducing infection by the virus. The face mask acts as a barrier for transmission of infected aerosols among its user and surrounding people. This has propelled pace of research and development of face masks around the world. This short review is an effort to present advances in materials and designs used for face masks. Details available in scientific literature and company brochures have been accessed and the use of nanomaterials and designs for the new generation of face masks have been discussed. Special attention was given to the face masks based on electrospun nanofiber-based membrane materials due to their nano-sized pores, light weight, and high filtration efficiency; therefore, they are commercially viable and popular among various products available in the market. Incorporation of metal organic framework (MOFs) and graphene have opened avenues to more advanced/multi-functional, reusable, and high capacity adsorption filtration membranes. Rapid prototyping/3-dimensional (3-D) printing techniques have been applied to shorten the time of manufacture of face masks. This review is expected to be very helpful for engineers, scientists, and entrepreneurs working on development of novel face masks required in plenty during this pandemic period.

A review of methods to reduce the probability of the airborne spread of COVID-19 in ventilation systems and enclosed spaces

COVID-19 forced the human population to rethink its way of living. The threat posed by the potential spread of the virus via an airborne transmission mode through ventilation systems in buildings and enclosed spaces has been recognized as a major concern. To mitigate this threat, researchers have explored different technologies and methods that can remove or decrease the concentration of the virus in ventilation systems and enclosed spaces. Although many technologies and methods have already been researched, some are currently available on the market, but their effectiveness and safety concerns have not been fully investigated. To acquire a broader view and collective perspective of the current research and development status, this paper discusses a comprehensive review of various workable technologies and methods to combat airborne viruses, e.g., COVID-19, in ventilation systems and enclosed spaces. These technologies and methods include an increase in ventilation, high-efficiency air filtration, ionization of the air, environmental condition control, ultraviolet germicidal irradiation, non-thermal plasma and reactive oxygen species, filter coatings, chemical disinfectants, and heat inactivation. Research gaps have been identified and discussed, and recommendations for applying such technologies and methods have also been provided in this article.

What do masks mask? A study on transdermal CO2 monitoring

Medical professionals have complained of extreme discomfort and fatigue from continuous wearing of N95 respirators (N95) overlaid with surgical masks (SM) and face shields (FS) during COVID-19 pandemic. However, there are no reports on the effect of face coverings on transdermal CO₂ (TrCO₂) levels (a measure of blood CO₂) during moderate activity. In this study, real-time monitoring of TrCO₂, heart rate and skin surface temperature was conducted for six subjects aged 20-59 years with and without wearing personal protective equipment (PPE). We initially studied the effect of wearing PPE (N95+SM+FS) at rest. Then, the effect of moderate stepping/walking activity (120 steps per minute for 60 min) while wearing PPE was evaluated. In addition, we investigated the effect of exercising intensity with different masks. We observed a significant difference (p < 0.0001) in TrCO₂ levels between without and with PPE during moderate exercise, but not while resting. TrCO₂ levels were correlated to exercise intensity independently with masking condition and breathability of masks. For the first time, we present data showing that a properly fitting N95 worn along with SM and FS consistently leads to elevated TrCO₂ under moderate exertion, which could contribute to fatigue over long-term use.

Materials in advanced design of personal protective equipment: a review

The outbreak of the Covid-19 pandemic has aroused tremendous attention toward personal protective equipment (PPE) in both scientific research and industrial manufacture. Despite decades of development in PPE design and fabrication, there's still much room for further optimization, in terms, of both protection performance and wear comfort. Interdisciplinary efforts have been devoted to this research field in recent years. Significantly, the innovation of materials, which brings about improved performance and versatile new functions for PPEs, has been widely adopted in PPE design. In this minireview, recent progress in the development of novel materials and structural designs for PPE application are presented in detail with the introduction of various material-based strategies for different PPE types, as well as the examples, which apply auxiliary components into face masks to enrich the functionalities and improve the personal feelings in the pandemic period.

Virucidal and biodegradable specialty cellulose nonwovens as personal protective equipment against COVID-19 pandemic

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Enable to instantly inactivate SARS-CoV-2 (>99.14%) and HCoV-229E (>98.83%).

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Excellent growth inhibition (>99.51%) towards both E. coli and S. aureus.

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Address the environmental concerns raised by non-biodegradable face masks.

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Development of safe, comfortable, and biodegradable textiles for PPE.

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A facile and scalable method to produce biocidal textiles for various applications.

Introduction

Face masks are regarded as effective Personal Protective Equipment (PPE) during the COVID-19 pandemic. However, the dominant polypropylene (PP)-based masks are devoid of antiviral/antibacterial activities and create enormous environmental burdens after disposal.

Objectives

Here we report a facile and potentially scalable method to fabricate biodegradable, breathable, and biocidal cellulose nonwovens (BCNWs) to address both environmental and hygienic problems of commercially available face masks.

Methods

TEMPO-oxidized cellulose nonwovens are rendered antiviral/antibacterial via covalent bonding with disinfecting polyhexamethylene guanidine or neomycin sulfate through carbodiimide coupling chemistry.

Results

The obtained results showed that the BCNWs have virucidal rate of >99.14%, bactericidal efficiency of >99.51%, no leaching-out effect, and excellent air permeability of >1111.5 mm s⁻¹. More importantly, the as-prepared BCNWs can inactivate SARS-CoV-2 instantly.

Conclusions

This strategy provides a new platform for the green fabrication of multifunctional cellulose nonwovens as scalable bio-protective layers with superior performance for various PPE in fighting COVID-19 or future pandemics. Additionally, replacing the non-biodegradable non-antimicrobial PP-based masks with the cellulose-based masks can reduce the plastic wastes and lower the greenhouse gas production from the incineration of disposed masks.

Challenges and Controversies in COVID-19: Masking the General Population may Attenuate This Pandemic's Outbreak

SARS-CoV-2, the virus that causes COVID-19, spreads i. a., by respiratory droplets. The use of masks in preventing spread is controversial; masks are considered useless by many, while being mandated in some locations. Here, the effect of masking the general population on a COVID-19-like epidemic is estimated by computer simulation using three separate types of software. The main questions are whether mask use by the general population can limit the spread of SARS-CoV-2 in a country and how to identify opportunities when mask use is cost-effective and safe. To address these questions, the protective effects of different types of masks, the side-effects of masks, and avenues for improvements of masks and masking are addressed. Main results: (i) Any type of mask, even simple home-made ones, may be of value, even if the protective effect of each mask (here dubbed "one mask-protection") is low. Strict adherence to mask use does not appear to be critical but increasing one mask-protection to >50% was found to be advantageous. (ii) Masks do seem to reduce the number of new cases even if introduced at a late stage in an epidemic, but early implementation helps reduce the cumulative and total number of cases. (iii) The simulations suggest that it might be possible to eliminate a COVID-19 outbreak by widespread mask use during a limited period. There is a brief discussion of why the reported effect size of masking varies widely, and is expected to do so, because of different filtration abilities of different masks, differences in compliance and fitting, other routes of transmission, pre-existing immunity, and because a system of interconnected, disease-prone individuals has non-linear properties. A software solution to visualize infection spread is presented. The results from these simulations are encouraging, but do not necessarily represent the real-life situation, so it is suggested that clinical trials of masks are now carried out while continuously monitoring effects and side-effects. As mask use is not without risks and costs, it is suggested that governments and scientists have an important role in advising the public about the sensible use of masks.

High-performance antiviral nano-systems as a shield to inhibit viral infections: SARS-CoV-2 as a model case study

Despite significant accomplishments in developing efficient rapid sensing systems and nano-therapeutics of higher efficacy, the recent coronavirus disease (COVID-19) pandemic is not under control successfully because the severe acute respiratory syndrome virus (SARS-CoV-2, original and mutated) transmits easily from human to -human and causes life-threatening respiratory disorders. Thus, it has become crucial to avoid this transmission through precautions and keep premises hygienic using high-performance anti-viral nanomaterials to trap and eradicate SARS-CoV-2. Such an antiviral nano-system has successfully demonstrated useful significant contribution in COVID-19 pandemic/endemic management effectively. However, their projection with potential sustainable prospects still requires considerable attention and efforts. With this aim, the presented review highlights various severe life-threatening viral infections and the role of multi-functional anti-viral nanostructures with manipulative properties investigated as an efficient precative shielding agent against viral infection progression. The salient features of such various nanostructures, antiviral mechanisms, and high impact multi-dimensional roles are systematically discussed in this review. Additionally, the challenges associated with the projection of alternative approaches also support the demand and significance of this selected scientific topic. The outcomes of this review will certainly be useful to motivate scholars of various expertise who are planning future research in the field of investigating sustainable and affordable high-performance nano-systems of desired antiviral performance to manage not only COVID-19 infection but other targeted viral infections as well.