Nanoscale aggregates of porphyrins: red-shifted absorption, enhanced absorbance and phototherapeutic activity

Abstract

Supramolecular aggregation of fluorophores will result in a variable absorption spectrum, which is beneficial for tuning the photophysical properties and improving their functionalities. Herein, ordered aggregates of liposoluble porphyrin molecules are obtained from 5,10,15,20-tetrakis(4-aminophenyl)porphyrin (TAPP). The influences of the molecular structures, solvents and polymer surfactants have been investigated, and then tetrahydrofuran and pluronic F-127 are screened out to be the optimal candidates for forming ordered aggregates of TAPP. The as-prepared aggregates of TAPP (TAPP-O NPs) exhibit a red-shifted absorption spectrum of 50 nm, enhanced absorbance in the near infrared region and improved photothermal activity. Particularly, the good phototherapeutic effects of TAPP-O NPs highlight the potential of aggregated organic materials for biomedical applications.