Abstract
Gold nanoclusters (Au NCs) have found wide range of applications in environmental, chemical and health sectors as sensors, catalytic agents and theranostic molecules, respectively, due to their ultrasmall size and excellent optical properties. However, a comprehensive battery of bioassays of Au NCs were lacking on a well-established biological model system, which would enhance its potential to be used as an optical probe with application in theranostics. The current investigation aims to address the in vivo compatibility of Au NCs to improve their design, evaluate their biological impact, and validate their potential for bioimaging applications. We have used the Caenorhabditis elegans as a model organism in our present study due to their short life cycle facilitating evaluation of drug effects in reasonable time frame and transparent body framework suitable for in vivo imaging. These features facilitate accurate information regarding the uptake and biodistribution of Au NCs inside the tissues and body parts. Additionally, different nanotoxicological studies such as biodistribution of NCs and its subsequent impact on the health span, brood size, pharyngeal pumping and tail thrashing of C. elegans were observed as a measure of the Au NCs biocompatibility. Our results strongly demonstrate that the human serum albumin (HSA)-bound Au NCs are non-toxic, biocompatible and do not exhibit any adverse effect on the physiology and survival of the C. elegans. This study, employing a comprehensive battery of bioassays, is the first to systematically evaluate the long-term biocompatibility and non-toxicity of Au NCs across the entire lifespan of an organism, measured through multiple physiological parameters. These findings underscore the potential of Au NCs as safe and effective diagnostic and therapeutic agents for medical and clinical applications.
