CAREER: Inorganic Nanoparticles with Biological Properties: Preparation, Characterization and Sensing Applications E. Silvana Andreescu, Clarkson University, DMR Figure 1. Redox reactivity of nanoceria particles against dopamine Control Ischemia Ischemia + Ceria Figure 2. Nanoceria based detection mechanism of alkaline phosphatase activity (ALP). Figure 4. Effect of soluble Cu on NO production within the intestine of zebrafish embryos and alterations in the enzymatic NO production by L-NAME. Fluorescence images (on the left panel) and the corresponding DPV voltammograms (on the right panel) obtained for unexposed embryos (A), for embryos exposed to 10  M CuSO 4 (B) and for embryos exposed to 10  M CuSO 4 and 3 mM L-NAME for 24 h before measurements (C). Incubation of embryos with CuSO 4 for 4 days results in visible increases in intestinal NO concentrations (B). Treatment of the CuSO 4 exposed embryos with L-NAME demonstrates non-enzymatic production of NO. As expected, the NO concentrations decrease with L-NAME but the observed NO levels are still higher than those of unexposed embryos. All embryos were incubated with 5  M DAF-FM-DA for 2 h before fluorescence imaging and were alive during imaging. Electrochemical recording were performed on live embryos without any additional preparation beyond electrode insertion. A B Intellectual merit Cerium oxide nanoparticles or nanoceria have a unique structure and interesting and unusual redox and catalytic properties that vary with the size, shape, surface coating and chemical reactivity. The goal of this project is to assess the biomimetic properties of these particles as replacement of natural enzymes. We aim to gain a fundamental understanding of their surface chemistry and composition and use these findings to develop highly robust and sensitive sensing platforms based on these materials. Major findings this year: -Established chemical reactivity of nanoceria against dopamine and other catecholamine neurotransmitters through a surface oxidation/chemisorption mechanism (Figure 1). -Established a nanoceria based catalytic amplification scheme for the ultrasensitive detection of enzyme activity (Figure 2). High sensitive detection of ultralow concentrations of analytes is of critical importance in the chemical laboratory and specialized areas of clinical diagnostic, food safety and environmental monitoring. This method can find wide applications in sensing schemes involving enzyme labels such as alkaline phosphatase (ALP), including the widely used ELISA, and can be used as a general approach for improving sensitivity and simplifying detection schemes of colorimetric bioassays, e.g. enzyme, gene, immuno and aptamer assays and related affinity methods. A. Hayat, D. Andreescu, G. Bulbul, S. Andreescu, Redox reactivity of cerium oxide nanoparticles against dopamine, J. Colloid Interface Science, 418, 2014, A. Hayat, G. Bulbul, S. Andreescu, Probing phosphatase activity using redox active nanoparticles: A novel colorimetric approach for the detection of enzyme activity, Biosensors and Bioelectronics, 56, 2014,

Broader Impact Nanoceria based sensors are currently being used as field portable devices for food and environmental quality monitoring. Student training in NSF Graduate Fellowship applications as part of the graduate/senior undergraduate course in Bioanalysis at Clarkson; Eleanor Vane, senior Clarkson undergraduate attending the class in 2013 has been awarded a NSF-Graduate Fellowship. Eleanor is now a graduate student at the University of Washington in Seattle. International Experience for graduate student Erica Sharpe : 3 months research at INRAN, Rome. Involvement of undergraduates in research: four chemistry and chemical engineering undergraduates worked on this project in : Jessica Cunningham, Nora Houlihan, Thalia Frasco and Amanda March (NSF-REU student). Two junior undergraduates have been recruited for CAREER: Inorganic Nanoparticles with Biological Properties: Preparation, Characterization and Sensing Applications E. Silvana Andreescu, Clarkson University, DMR Two PhD thesis completed: Erica Sharpe, PhD now Assistant Professor at State University of New York at Canton Emrah Ozel, PhD now Postdoctoral scholar at University of California, Santa Cruz