文摘
Peptide-coated quantum dot-photosensitizer conjugates were developed using novel covalentconjugation strategies on peptides which overcoat quantum dots (QDs). Rose bengal and chlorin e6,photosensitizers (PSs) that generate singlet oxygen in high yield, were covalently attached to phytochelatin-related peptides. The photosensitizer-peptide conjugates were subsequently used to overcoat green- andred-emitting CdSe/CdS/ZnS nanocrystals. Generation of singlet oxygen could be achieved via indirectexcitation through Förster (fluorescence) resonance energy transfer (FRET) from the nanocrystals to PSs,or by direct excitation of the PSs. In the latter case, by using two color excitations, the conjugate could besimultaneously used for fluorescence imaging and singlet oxygen generation. Singlet oxygen quantumyields as high as 0.31 were achieved using 532-nm excitation wavelengths.