Unfolding of the SARS-CoV-2 spike protein through infrared and ultraviolet-C radiation based disinfection

• DOI: 10.1016/j.ijbiomac.2022.08.197
• Publication Date: 2022-09-03T02:26:01Z
• Authors: Nilkamal Mahanta; Swati Sharma; Laipubam Gayatri ...; Lalit M. Pandey; Uday Shanker Dixit
• Keywords: Disinfection; Staphylococcus aureus; 0303 health sciences; 03 medical and health sciences; SARS-CoV-2; Ultraviolet Rays; Spike Glycoprotein, Coronavirus; Humans; COVID-19; Respiratory Aerosols and Droplets; Article; 3. Good health

The spreading of coronavirus from contacting surfaces and aerosols created a pandemic around the world. To prevent the transmission of SARS-CoV-2 virus and other contagious microbes, disinfection of contacting surfaces is necessary. In this study, a disinfection box equipped with infrared (IR) radiation heating and ultraviolet-C (UV-C) radiation is designed and tested for its disinfection ability against pathogenic bacteria and SARS-CoV-2 spike protein. The killing of a Gram-positive, namely, S. aureus and a Gram-negative namely, S. typhi bacteria was studied followed by the inactivation of the spike protein. The experimental parameters were optimized using a statistical tool. For the broad-spectrum antibacterial activity, the optimum condition was holding at 65.61 °C for 13.54 min. The killing of the bacterial pathogen occurred via rupturing the cell walls as depicted by electron microscopy. Further, the unfolding of SARS-CoV-2 spike protein and RNase A was studied under IR and UV-C irradiations at the aforesaid optimized condition. The unfolding of both the proteins was confirmed by changes in the secondary structure, particularly an increase in β-sheets and a decrease in α-helixes. Remarkably, the higher penetration depth of IR waves up to subcutaneous tissue resulted in lower optimum disinfection temperature, <70 °C in vogue. Thus, the combined UV-C and IR radiation is effective in killing the pathogenic bacteria and denaturing the glycoproteins.