Understanding the interaction of nanoparticles (NPs) with biological systems and assessing how exposure to NPs affects biological and chemical mechanisms in living systems is of critical importance. One of the key nanotoxicity mechanisms is the potential for induction of oxidative stress by generating reactive oxygen (ROS) and nitrogen (RNS) species. However, assessing the extent of NPs induced oxidative stress has been a challenge as most ROS and RNS are highly reactive and short lived and therefore difficult to detect. This proposal addresses this fundamental problem by developing methodologies for direct real-time assessment of ROS and RNS species at the NPs accumulation site in a living aquatic system, zebrafish embryos and 2 week juveniles,and correlating the observed oxidative effects with their cytotoxicity at the tissue and organ level including alteration of the oxidative/anti-oxidative biological mechanism, cellular damage, inflammation induction, and apoptosis.
Intellectual Merit : Exposure of living systems to NPs may alter the antioxidant-defense system and redox mechanisms in cells, tissues and organs. The goal of this proposal is to gain fundamental understanding of the mechanism of oxidative stress response due to exposure to engineered NPs in an intact live organism: zebrafish. Research work will focus on the engineering design of new nanotoxicity probes for direct detection of ROS/RNS and their use to establish whether NPs generate free radicals or change the physiological oxidative status of organs that accumulate NPs due to toxicity. Results will provide local concentration profiles of ROS/RNS in the zebrafish intestine following exposure to various doses of NPs. Research will identify properties of the NPs that regulate interactions with ROS/RNS species and determine the role of surface reactivity and reaction kinetics. Cell and tissue damage, malformations and viability will be studied and related with ROS/RNS production in zebrafish. Fundamental understanding on how the physicochemical and surface properties of the particles change in contact with reactive ROS/RNS species, quantified by in vitro electrochemical measurements of single NP collision studies with microelectrodes, will also be used to establish predictive models of NPs induced oxidative stress. The technology can be widely used to measure oxidative status in a variety of other organs, cell cultures, tissues, and other environmental conditions. The data will be used for risk assessment of NPs which will facilitate development of a new paradigm for predicting NPs induced oxidative stress using a relatively simple, inexpensive and rapid screening method. The success of this method would enable faster high throughput screening of NPs, as an alternative to animal experimentation.
Broader Impacts : The project will create new tools and methodologies for nanotoxicity assessment and generate fundamental knowledge that can solve key questions in understanding the effect of NPs exposure to the environment and living systems, specifically those related to oxidative stress. The results of the proposed studies will provide an "oxidative profile" of the behavior and transport of NPs in biological systems starting from the material characteristics to organ and tissue response. It will enable development of novel nanotoxicity probes for direct assessment of NPs induced oxidative stress and permit identification of the key factors in the NPs surface properties and reactivity that can be used to predict toxicity, permit targeted screening, and allow controlled generation of new, safer NPs based on structure-toxicity information. Understanding these mechanisms may provide guidelines for modifications to NPs to prevent this type of damage. Moreover, this effort will enable the education and training of undergraduate and graduate students, especially minorities and women, in the field of nanotoxicology and sustainable material development at the interface with biological systems, and make them aware of the potential implications and risks of the newly developed engineered materials in the environment, ecosystem and biological systems. Concepts of oxidative stress and environmental and health impacts will be introduced in local high schools in upstate New York. A course on environmental health and safety implications of nanotechnology will be created for the interdisciplinary Biotechnology, Materials Science and the Environmental Science and Engineering programs at Clarkson University, and broadly disseminated to nearby 4-year colleges and open access on the Clarkson website.
