CAREER: Inorganic Nanoparticles with Biological Properties: Preparation, Characterization and Sensing Applications E. Silvana Andreescu, Clarkson University, DMR 0954919 Figure 1. Redox reactivity of nanoceria particles against dopamine Control Ischemia Ischemia + Ceria Figure 2. Nanoceria based detection mechanism of alkaline phosphatase activity (ALP). 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 A. Hayat, D. Andreescu, G. Bulbul, S. Andreescu, Redox reactivity of cerium oxide nanoparticles against dopamine, J. Colloid Interface Science, 418, 2014, 240-245. 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, 2014,334-339.