the virus has been detected in nearly every country and a pandemic was declared by the World Health Organization (WHO) in March 2020. As of 3 May 2021, the WHO reported that at least 146 million people worldwide have contracted COVID-19 with more than 3.1 million confirmed deaths. [2] Through genomic sequencing and phylogenetic analysis, it was discovered that COVID-19 has a large resemblance to two bat-derived SARS-like coronaviruses with 88% similarity. [3,4] While COVID-19 has a low mortality rate, it is highly transmissible and infectious. [4] In human-tohuman transmission, the virus is most commonly disseminated by respiratory droplets released through coughing, sneezing and talking. [5] The widespread global infection rate of the virus can be attributed to its long incubation period (ranging 2-14 days) and transmission from asymptomatic hosts. [4][5][6] To curb further spread of the virus, the use of protective face masks such as surgical masks and N95 respirators was recommended as a preventive measure. [6,7] The U.S. Food and Drugs Administration (FDA) defines a surgical mask as a loose-fitting, To curb the spread of the COVID-19 virus, the use of face masks such as disposable surgical masks and N95 respirators is being encouraged and even enforced in some countries. The widespread use of masks has resulted in global shortages and individuals are reusing them. This calls for proper disinfection of the masks while retaining their protective capability. In this study, the killing efficiency of ultraviolet-C (UV-C) irradiation, dry heat, and steam sterilization against bacteria (Staphylococcus aureus), fungi (Candida albicans), and nonpathogenic virus (Salmonella virus P22) is investigated. UV-C irradiation for 10 min in a commercial UV sterilizer effectively disinfects surgical masks. N95 respirators require dry heat at 100 °C for hours while steam treatment works within 5 min. To address the question on safe reuse of the disinfected masks, their bacteria filtration efficiency, particle filtration efficiency, breathability, and fluid resistance are assessed. These performance factors are unaffected after 5 cycles of steam (10 min per cycle) and 10 cycles of dry heat at 100 °C (40 min per cycle) for N95 respirators, and 10 cycles of UV-C irradiation for surgical masks (10 min per side per cycle). These findings provide insights into formulating the standard procedures for reusing masks without compromising their protective ability.

Disinfection using effective antimicrobials is essential in preventing the spread of infectious diseases. This COVID‐19 pandemic has brought the need for effective disinfectants to greater attention due to the fast transmission of SARS‐CoV‐2. Current active ingredients in disinfectants are small molecules that microorganisms can develop resistance against after repeated long‐term use and may penetrate the skin, causing harmful side‐effects. To this end, a series of membrane‐disrupting polyionenes that contain quaternary ammoniums and varying hydrophobic components is synthesized. They are effective against bacteria and fungi. They are also fast acting against clinically isolated drug resistant strains of bacteria. Formulating them with thickeners and nonionic surfactants do not affect their killing efficiency. These polyionenes are also effective in preventing infections caused by nonenveloped and enveloped viruses. Their effectiveness against mouse coronavirus (i.e., mouse hepatitis virus‐MHV) depends on their hydrophobicity. The polyionenes with optimal compositions inactivates MHV completely in 30 s. More importantly, the polyionenes are effective in inhibiting SARS‐CoV‐2 by >99.999% within 30 s. While they are effective against the microorganisms, they do not cause damage to the skin and have a high oral lethal dose. Overall, these polyionenes are promising active ingredients for disinfection and prevention of viral and microbial infections.

A quaternary ammonium-functionalized cationic polymer synergizes with existing chemotherapeutics and re-purposes antibiotics to increase therapeutic efficacy, mitigate toxicity and circumvent drug resistance via its membrane disruption mechanism.