Biocompatible nanoparticles of amphiphilic cyclodextrins entangling porphyrins as suitable vessels for light-induced energy and electron transfer

In this contribution we explore the capability of biocompatible nanoparticles (NPs) of cationic amphiphilic cyclodextrins entangling the anionic hydrophilic 5,10,15,20-tetrakis(4- sulfonatophenyl)-21H,23H-porphyrin (TPPS) to facilitate photoinduced energy and electron transfer with suitable donor and acceptor guest molecules, by using a combination of absorption, induced circular dichroism and fluorescence spectroscopy. It is shown that anthracene (AN) and anthraquinone-2-sulfonate (AQS), chosen as appropriate energy donor and electron acceptor, respectively, can be trapped within the NPs network. Fluorescence experiments carried out in the presence and, for comparison, in the absence of NPs provide clear evidence that the amphiphilic NPs strongly encourage singlet-singlet energy transfer from AN to TPPS as well as photoinduced electron transfer from TPPS to AQS. In view of the biocompatibility and drug-carring properties of the NPs used, these results can be of interest from the perspective of designing photo-activated drug delivery systems.