Antimicrobial Photodynamic Therapy with Functionalized Fullerenes: Quantitative Structure-activity Relationships
- *Corresponding Author:
- Michael R Hamblin
BAR414, 40 Blossom Street
Massachusetts General Hospital
Boston, MA02114, USA
E-mail: [email protected]
Received Date: February 15, 2011; Accepted Date: March 31, 2011; Published Date: April 01, 2011
Citation: Mizuno K, Zhiyentayev T, Huang L, Khalil S, Nasim F, et al. (2011) Antimicrobial Photodynamic Therapy with Functionalized Fullerenes: Quantitative Structure-activity Relationships. J Nanomedic Nanotechnol 2:109. doi:10.4172/2157-7439.1000109
Copyright: © 2011 Mizuno K, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Photosensitive dyes or photo sensitizers (PS) in combination with visible light and oxygen produce reactive oxygen species that kill cells in the process known as photodynamic therapy (PDT). Antimicrobial PDT employs PS that is selective for microbial cells and is a new treatment for infections. Most antimicrobial PS is based on tetrapyrrole or phenothiazinium structures that have been synthesized to carry quaternary cationic charges or basic amino groups. However we recently showed that cationic-substituted fullerene derivative were highly effective in killing a broad spectrum of microbial cells after illumination with white light. In the present report we compared a new group of synthetic fullerene derivatives that possessed either basic or quaternary amino groups as antimicrobial PS against Grampositive (Staphylococcus aureus), Gram-negative bacteria (Escherichia coli) and fungi (Candida albicans). Quantitative structure-function relationships were derived with LogP and hydrophilic lipophilic balance parameters. Compounds with non-quaternary amino groups tended to form nanoaggregates in water and were only effective against S. aureus. The most important determinant of effectiveness was an increased number of quaternary cationic groups that were widely dispersed around the fullerene cage to minimize aggregation. S. aureus was most susceptible; E. coli was intermediate, while C. albicans was the most resistant species tested. The high effectiveness of antimicrobial PDT with quaternized fullerenes suggest they may have applications in treatment of superficial infections (for instance in wounds and burns) where light penetration into tissue is not problematic.