OBTAINING NANODIAMONDS FUNCTIONALIZED WITH NATURAL PHOTOSENSITIZERS FOR APPLICATION IN ANTIMICROBIAL PHOTODYNAMIC THERAPY

Abstract

Nanotechnology has shown potential in the infections treatment, through the use of nanoparticulate systems. Nanodiamonds (NDs) are among the promising materials for biomedical application due to biocompatibility, being used as: drug delivery; implant coating; fluorescent probes and antimicrobial active. Modifications chemical reactions on the surface of NDs, with photosensitizers (PS), can confer characteristics suitable for application in Photodynamic Therapy (PDT - PhotoDynamic Therapy). This is a non-antibiotic therapy, which provides cell death in the presence of FS, activated by irradiation light in the presence of oxygen, generating reactive species (ROS) that cross membranes cells, causing oxidative damage to target cells. The molecules of the FS can be of origin natural or synthetic, and the first reported photoactive drugs were extractedof plants. The diversity of natural FS structures calls the attention of researchers because demonstrate impressive characteristics to act in the PDT. Hypericin and Fagopyrin are FS present in the plants Hypericum perforatum and Fagopyrum esculentum, respectively, and which exhibit antimicrobial activity when stimulated by light irradiation, decreasing side effects of traditional therapies. Despite its important biological effects, there is no conjugation studies with NDs for use in PDT, enabling the formation of a nanosystem drug carrier. Thus, the present study aims at the extraction and purification of natural FS: hypericin and fagopyrin, followed by the study of synthetic routes of conjugation with NDs, evaluating the ROS generation capacity, obtaining nanosystems with potential for application in PDT antimicrobial.