Photomodulation of bacterial growth and biofilm formation using carbohydrate-based surfactants

Abstract

Naturally occurring and synthetic carbohydrate amphiphiles have emerged as a promising class of antimicrobial and antiadhesive agents that act through a number of dynamic and often poorly understood mechanisms. In this paper, we provide the first report on the application of azobenzene <i>trans</i>-<i>cis</i> photoisomerization for effecting spatial and temporal control over bacterial growth and biofilm formation using carbohydrate-based surfactants. Photocontrollable surface tension studies and small angle neutron scattering (SANS) revealed the diverse geometries and dimensions of self-assemblies (micelles) made possible through variation of the head group and UV-visible light irradiation. Using these light-addressable amphiphiles, we demonstrate optical control over the antibacterial activity and formation of biofilms against multi-drug resistant (MDR) <i>Pseudomonas aeruginosa</i>, methicillin-resistant <i>Staphylococcus aureus</i> (MRSA) and Gram-negative <i>Escherichia coli</i>. To probe the mechanism of bioactivity further, we evaluated the impact of <i>trans</i>-<i>cis</i> photoisomerization in these surfactants on bacterial motility and revealed photomodulated enhancement in swarming motility in <i>P. aeruginosa</i>. These light-responsive amphiphiles should attract significant interest as a new class of antibacterial agents and as investigational tools for probing the complex mechanisms underpinning bacterial adhesion and biofilm formation.