Flame synthesis of functional nanoparticles: Non-toxic nanosilver for biosensors

Date: 02/04/2011
Time: 12:00 pm – 1:00 pm
Location: 333 Curry Student Center
Speaker: Dr. Sotiris E. Pratsinis, Professor, ETH Zurich, Switzerland

“Mixed oxides and even pure metals are made now in flames resulting in new catalyst, phosphor, gas sensor, battery, dental & orthopaedic materials and even nutritional supplements, way beyond today’s flame-made commodities of carbon black, fumed SiO2 & pigmentary SiO2. Recent advances in our labs include in-situ surface functionalization and coating of flame-made core oxide (TiO2, Fe2O3) metal, LiMn2O4 or LiFePO4 nanoparticles with nanothin carbon or silica shells. Furthermore, nanoscale devices with tailored conductivity are made by stochastically depositing, above or below a functional nanofilm, conductive nanoparticles that greatly reduce film resistance motivating the development of acetone sensors for early detection and monitoring of diabetes type-1 by breath analysis.

Abstract:After this overview, I will focus on nanosilver, one of the first nanomaterials for which US EPA had been petitioned to label it as “pesticide” for its toxicity on microorganisms. By immobilizing Ag on nanostructured SiO2 particles and close control of its size, it is shown how Ag+ ions dominate the antibacterial activity against E. coli when fine Ag nanoparticles (< 10 nm) are used. In contrast, with relatively larger Ag particles, leached Ag+ ions are reduced drastically. This now guides synthesis of non-toxic nanosilver by coating it with nanothin SiO2 shells to exploit its superior plasmonic properties and evaluate its performance as biosensor with bovine serum albumin and even raji cells if time permits it.”

Sotiris E. Pratsinis (Ph.D. Eng. UCLA 1985) was Professor (1985-2000) and interim Head (1998) of Chemical Engineering at the University of Cincinnati, Ohio, USA until he was elected Professor (1998) and Head (2007-2009) of Mechanical and Process Engineering in 1998 and Adjunct Professor of Materials Science (2003) at ETH Zurich. There he teaches Mass Transfer, Micro- and Nano-Particle Technology, Nanoscale Engineering and Combustion Synthesis of Materials.

He has graduated 24 Ph.D. students and is currently advising 12. He has published 300+ refereed articles and received 15 patents licensed to Dow, Degussa, Hosokawa-Micron and others while he has contributed to the formation of four spinoffs. His program has been funded by the U.S. & Swiss National Science Foundations, DuPont, Nestle, Toyota, Ivoclar-Vivadent, Clariant, Nestle, Buehler etc. He has received a 1989 Presidential Young Investigators Award by the U.S. NSF and a 2009Advanced Investigator Grant by the European Research Council. In 2005 he became Springer Professor of Mechanical Engineering at University of California, Berkeley. He is on the Editorial Boards of six journals and currently Visiting Professor at the Harvard School of Public Health.