Light-based technologies for management of COVID-19 pandemic crisis

Abstract

The global dissemination of the novel coronavirus disease (COVID-19) has accelerated the need for the implementation of effective antimicrobial strategies to target the causative agent SARS-CoV-2. Light-based technologies have a demonstrable broad range of activity over standard chemotherapeutic antimicrobials and conventional disinfectants, negligible emergence of resistance, and the capability to modulate the host immune response. This perspective article identifies the benefits, challenges, and pitfalls of repurposing light-based strategies to combat the emergence of COVID-19 pandemic.

Keywords: germicidal; photobiology; photobiomodulation; photodynamic; photoinactivation; ultraviolet; virucidal.

Fig. 1

Mechanisms of photosensitized oxidation reactions. The photosensitizer (PS) is a molecule capable of absorbing light depending on its specific absorption spectra. Once excited, the PS is converted from the ground state ¹PS to its singlet excited ¹PS^⁎ and triplet excited ³PS^⁎ states. Via Type I (contact-dependent) reactions both ¹PS^⁎ and ³PS^⁎ can react directly with O₂ or biomolecules, like carbohydrates, lipids, proteins, or nucleic acids, resulting in the formation of radicals capable of initiating redox chain reactions. Otherwise, ³PS^⁎ can react with molecular oxygen (³O₂), via the Type II (energy transfer) reaction, generating the reactive state of singlet oxygen (¹O₂).