Visible‐Light‐Triggered Degradation of pH‐Responsive Micelles Based on ortho‐Hydroxy Cinnamates

摘要

Abstract Micelles made by connecting hydrophobic and hydrophilic chains via photo‐responsive ortho‐hydroxy cinnamate (oHC) units undergo complete degradation within 10?min under visible light irradiation at basic pH values. This proof of concept relies on the controlled cyclization of the oHC moiety affording the corresponding coumarin with the concomitant separation of the hydrophobic portion. Furthermore, the neat polymeric micelles are stable under daylight conditions, thus allowing its storage without special precautions at neutral?pH. The amphiphilic nature of mPEG750‐oHC‐dodecyl, expressed as the ability to self‐assemble into micellar aggregates in aqueous media, was corroborated by the measurement of its critical micellar concentration (CMC) by fluorescence analysis, as well as the successful visualization of these aggregates using transmission electron microscopy (TEM). Moreover, the size distribution and suspension stability of these aggregates obtained at different pH values was analyzed in terms of dynamic light scattering (DLS) and zeta potential measurements.