The Photodynamic Effect of ZnO Nanorods and Their Ligands with Different Photosensitizers

Zinc oxide (ZnO) nanorods (NRs) and ZnO nanoparticles (NPs) conjugated with photosensitizers (5-aminolevulinic acid (ALA), protoporphyrin dimethyl ester (PPDME), or photofrin^® are activated by ultraviolet (UV) or visible light and this have lead to the production of singlet oxygen in the different cell lines (Breast cancer, normal Fibroblast, Melanoma, HeLa, Hep2c, Rhybdomyosarcoma, HEK293T, HepG2). This process has ultimately resulted in cell necrosis in all the above cell lines. This process was studied using inverted microscope (Zeiss) through the technique of mitotracker staining, by recognizing the mitochondria and its disappearance. ZnO conjugated photosensitizers have synergetic effect for cytotoxicity under exposure to UV or visible light for malignant cells, and can be used as cancer cell killing drug. Cell viability was studied by Neutral Red Assay (NRA) and MTT assay as well as by confocal laser scanning microscope to visualize the morphological and biological changes in cells. Our results conclude that ZnO NRs and NPs are bio-safe and biocompatible in dark but toxic in the presence of UV. ZnO NRs when conjugated with PPDME, form a ligand which is convincing candidate for the treatment for melanocitic carcinoma. Biodistribution of ^99mTc Labeled PHOTOFRIN^® in Sprague-Dawley Rats was standardized and more than 95% labeling efficacy of radiolabeling of PHOTOFRIN^® with ^99mTc was achieved. The current technique is more simple and effective as compared to the previous procedures adopted for effectiveness of PDT.