Impact of Single-Walled Carbon Nanotubes on Growth and Reproductive Parameters in Fish

University Of Florida, Gainesville FL

Investigators

Abstract

Abstract #1236029 Sabo-Attwood, Tara Nanomaterials (NM) have emerged as high-performance entities with application in numerous sectors, including electronic, optical, medical, and structural composite technologies. Because of their anticipated role in large-scale industrial production, there is little doubt that select NM will ultimately find their way into our aquatic environment. There is a lack of fundamental studies that have investigated the effects of single-walled carbon nanotube (SWNT) biological interactions and effects in aquatic organisms, particularly through chronic dietary exposure routes, and even fewer that have addressed mechanisms of action. Therefore we have limited understanding of the potential toxicity associated with environmentally relevant exposures. The purpose of this proposal is to fundamentally understand the sub-lethal effects of SWNTs with a focus on elucidating their role in limiting growth and reproduction in largemouth bass (LMB), a well characterized environmentally relevant freshwater model for reproductive toxicological assays. We are particularly interested in investigating the ability of pristine non-surface functionalized SWNTs to alter the gastrointestinal (GI) environment through direct tissue damage and/or sequestering proteins vital to digestion and absorption of dietary constituents. The study design involves a systematic top down approach spanning in vivo fish exposures to mechanistic in vitro assays. We will accomplish these studies through the following specific tasks; (1) Track SWNT distribution using a custom built near-infrared fluorescent (NIRF) imaging system and assess growth following dietary exposures to LMB; (2) Assess the impact of SWNTs and estrogen enriched diets on reproductive endpoints including measurements of vitellogenin and steroids (17β-estradiol and 11-keto-testosterone) in plasma by ELISA and determination of estrogen receptor binding and activation using fluorescence polarization and gene reporter assays, respectively; (3) Determine suites of proteins bound to SWNTs in intestinal tissues and blood using proteomics strategies. The proposed research will fill a critical gap in the scientific literature by providing a systematic understanding of the growth and reproductive effects of ingested SWNTs. This will also be the first study to address specific mechanisms of action (MOA) by employing a suite of molecular assays and proteomic strategies. These studies will be fully novel, as there are no fundamental mechanistic reports that have examined the impact of SWNTs on growth and reproductive processes through disruption of the GI tract and endocrine system in fish. Results of this study may lead to biological relations for SWNTs in aquatic environments, allowing a priori predictions of their fate and effects and therefore meets the definition set forth by the NSF for transformative research. Intellectual Merit. The expected research outcomes and benefits include systemic tracking of SWNTs in whole animals; advanced understanding of chronic dietary exposures to SWNT on the endocrine system; revealing the interactions of SWNTs with biological molecules and specific MOA including receptor activation and cell production of steroids . This increase in basic scientific knowledge will ultimately lead to understanding relevant environmental exposure scenarios and sub-lethal biologic effects that could impact aquatic organisms at the population level. Broader Impacts. The proposed activity will generate critical knowledge to better understand the environmental implication of a commercially important class of nanomaterials. The majority of requested funds are directed toward the training of a postdoctoral associate in an emerging and interdisciplinary research topic. This research will provides for mentoring and cross training (molecular signaling and proteomics) in a novel and highly relevant area that is of immediate and critical importance to our society. The postdoctoral training program integrates classroom and hands on laboratory training and the opportunity to mentor minority graduate and undergraduate students recruited to work in the lab. Dissemination of the research results is planned through conference presentations, peer-reviewed publications and research symposiums.