Abstracts

Antimicrobial photodynamic therapy (aPDT) has beneficial effects in dental treatment. We applied captopril-protected gold (Au25(Capt)18) clusters as a novel biosafe photosensitizer for aPDT. Photoexcited Au25(Capt)18 clusters under dental blue light emitting diode (LED) irradiation generated a singlet oxygen (1O2). Accordingly, the antimicrobial and cytotoxic effects of Au25(Capt)18 clusters under blue LED irradiation were evaluated. Successful application of photoexcited Au25(Capt)18 clusters to aPDT was demonstrated by dose-dependent decrease in the turbidity of oral bacterial cells, such as Streptococcus mutans, Aggregatibacter actinomycetemcomitans and Porphyromonas gingivalis. In addition, blue LED use alone slightly diminished the turbidity of bacterial cells. Morphological observation revealed that application of clusters stimulated destruction of bacterial cell walls. However, photoexcited Au clusters did not negatively affect the adhesion, spreading and proliferation of NIH3T3 and MC3T3-E1 cells, in particular, at lower dose. In comparative assessments of Au clusters and methylene blue, Au25(Capt)18 clusters had higher biocompatibility than methylene blue. We found that a combination of Au25(Capt)18 clusters and blue LED irradiation exhibited good antimicrobial and biosafe characteristics, which would be desirable for aPDT in dental use. 41p Hokkaido University. ()