SURFACE AREA : A STUDY TO FACILITATE NANOSAFETY STUDIES ARCHINI PARUTHI PhD SCHOLAR (NANOTOXICITY) MATERIALS SCIENCE AND ENGINEERING INDIAN INSTITUTE OF TECHNOLOGY GANDHINAGAR INDIA

RATIONALE TOXICITY OF NANOPARTICLES SO 4 - Cl - Surface Chemistry Size and Surface Area Extrinsic Factors Mg+ Na+  Surface area as a metric to study reactivity (Specific vs Wetted Surface area)  Bioavailability of particles under realistic conditions

METHODOLOGY Wetted surface area evaluation Credit :

RESULTS : Basic Physico-chemical Characterization Sample (n=3) Average BET Surface Area (m 2 /g) Average Pore Volume (cm 3 /g) Average Pore Size (nm) CuO22.17± ZnO10.03± SiO ± No assumption regarding sphericity SiO2 NPs ZnO NPs CuO NPs

RESULTS : Relaxation Time Data for Stability

SELECTED REFERENCES Visit ACKNOWLEDGEMENT PI : Dr. Superb K Misra  Cooper, C. L., Cosgrove, T., Duijneveldt, J. S. Van, Murray, M., & Prescott, S. W. (2013). The use of solvent relaxation NMR to study colloidal suspensions. Soft Matter, 9(30), 7211–  Covered, T., Surface, P., & Measurement, A. (n.d.). Powder Surface Area Measurement Comparison - BET vs Xigo Nanotools Acorn Area Comparison of Surface Area Data, 1–4.  Features, K. (n.d.). Acorn Area - Particle Analyzer from Xigo Nanotools - Particle Surface Area of Wetted Dispersions, 1– 4.  Halle, B., & Piculell, L. (1986). Water Spin Relaxation in Colloidal Systems. Journal of the Chemical Society, Faraday Transactions, 82, 415–429.  Koenig, S. H., & Brown, R. D. (1985). Relaxation of Solvent Protons By Paramagnetic Ions and Its Dependence on Magnetic Field and Chemical Environment. Journal of Computer Assisted Tomography, 9(2),

Additional Information : Mathematical formulations for SA calculations (* Not a part of the presentation) SymbolsNomenclatureComments R av Average spin relaxation rate Ψ P Particle volume to liquid volume ratio SSurface area per unit mass (Sp. Surface area) k A RelaxivityDependent on particle type and dispersing solvent ρ P Bulk particle density S tot Total wetted surface area R av = Ψ P SLρ P [R s -R b ]+R b R av = k A SΨ P + R b k A = Lρ P [Rs-Rb] R nd(av) = p s R ns + p b R nb S tot = R sp R b /k A Ψ P Relaxation time =1/Spin relaxation rate (R nd )