Antimicrobial Blue Light: A ‘Magic Bullet’ for the 21st Century and Beyond?

Abstract Over the past decade, antimicrobial blue light (aBL) at 400 nm - 470 nm wavelength has demonstrated immense promise as an alternative approach for the treatment of multidrug-resistant microbes. Since our last review was published in 2017, there have been numerous studies that have investigated the efficacy, safety, mechanism, and propensity for resistance development. In addition, researchers have looked at combinatorial approaches that exploit aBL and other traditional and non-traditional therapeutics. To that end, this review aims to update the findings from numerous studies that capitalize on the antimicrobial effects of aBL, with a focus on: efficacy of aBL against different microbes, identifying endogenous chromophores and targets of aBL, Resistance development to aBL, Safety of aBL against host cells, and Synergism of aBL with other antimicrobials. We will also discuss our perspective on the future of aBL.