Visible light-activatable multicargo microemulsions with bimodal photobactericidal action and dual colour fluorescence

Abstract

In this contribution we report the design, preparation, and physico-chemical, photophysical and photochemical characterization of photoactivatable microemulsions (MEs) based on Labrasol®, isopropanol and Lauroglycol® FCC as a surfactant, co-surfactant and oily phase, respectively. The MEs co-incorporate, in their oil phase, two lipophilic guests such as a red emitting singlet oxygen (¹O₂) photosensitizer (PS) and a tailored green emitting nitric oxide (NO) photodonor (NOPD). These two chromofluorogenic units absorb in different spectral windows of the visible range, and their individual photophysical and photochemical properties are well-conserved when co-entrapped in the microemulsions. These features permit the PS and NOPD to operate either individually or in tandem resulting in (i) red, green or both fluorescence emission, (ii) photogeneration of cytotoxic ¹O₂, NO or both and (iii) amplified photobactericidal action against Staphylococcus aureus due to the combined effect of these two antibacterial agents.