Comet assay: a method to evaluate genotoxicity of nano-drug delivery system.

INTRODUCTION Drug delivery systems could induce cellular toxicity as side effect of nanomaterials. The mechanism of toxicity usually involves DNA damage. The comet assay or single cell gel electrophoresis (SCGE) is a sensitive method for detecting strand damages in the DNA of a cell with applications in genotoxicity testing and molecular epidemiology as well as fundamental research in DNA damage and repair. METHODS In the current study, we reviewed recent drug delivery researches related to SCGE. RESULTS We found that one preference for choosing the assay is that comet images may result from apoptosis-mediated nuclear fragmentation. This method has been widely used over the last decade in several different areas. Overall cells, such as cultured cells are embedded in agarose on a microscope slide, lysed with detergent, and treated with high salt. Nucleoids are supercoiled DNA form. When the slide is faced to alkaline electrophoresis any breakages present in the DNA cause the supercoiling to relax locally and loops of DNA extend toward the anode as a ''comet tail''. CONCLUSION This article provides a relatively comprehensive review upon potentiality of the comet assay for assessment of DNA damage and accordingly it can be used as an informative platform in genotoxicity studies of drug delivery systems.