Photosensitizing properties of hollow microcapsules built by multilayer self-assembly of poly(allylamine hydrochloride) modified with rose Bengal

SERRANO, MARIANA P.; RAFTI, MATÍAS; THOMAS, ANDRÉS H.; BORSARELLI, CLAUDIO D.

RSC Advances

RSC

Lugar: londres; Año: 2019 vol. 9 p. 19226 - 19235

A polymeric photosensitizer based on poly(allylamine hydrochloride) (PAH) and rose Bengal (RB) wassynthesized. The modified polycation PAH-RB was demonstrated to be suitable for construction ofmicrocapsules via a layer-by-layer (LbL) assembly technique, using sodium poly(styrene sulfonate) (PSS)as counter-polyelectrolyte and CaCO3 microcrystals as templates. After CaCO3 core removal, a stablesuspension of hollow microcapsules with shells incorporating RB (HM-RB) was obtained. Thespectroscopic and photophysical behavior of both PAH-RB and HM-RB in aqueous environments werestudied and described in terms of dye?dye interactions and dye hydrophobicity. Only HM-RB was ableto generate singlet molecular oxygen with similar efficiency to free RB in air-saturated solutions upongreen light irradiation. In order to explore possible practical applications as a supramolecularphotosensitizer, experiments of HM-RB irradiation in the presence of chemically and biologically relevanttarget molecules were carried out. It was observed that is possible to use visible light to initiate thephotooxidation of biological compounds in water, with many interesting advantages compared to lowmolecular-weight photosensitizers such as an enhancement of the photosensitizing effect, due toa significant reduction of dye?dye interaction, or improved reuse given the straightforward size-basedseparation from the reaction mixture without loss of efficiency