Engineered ferrofluid for pathogen detection and cellular manipulation

by Birgit Fischer, Electrical Engineering Dept., Yale University, USA

Monday 30 Jun 2008, 14:00 → 15:00 Europe/Berlin

Bldg. 25b, Sem.R. 109

Ferrofluids are colloidal suspensions comprised of nanosized magnetic particles that are stabilized with a surfactant. Ferrofluids have significant potential in a variety of biological applications, including pathogen sensing and cellular manipulation. One of the main challenges that still remains in this context is the difficulty to render a ferrofluid sample biofunctional without labor-intensive and lengthy chemical procedures and drastic changes in its physical properties. Here we present a novel, rapid and labor-free biofunctionalization scheme for ferrofluids based on silica covered magnetic nanoparticles. We have demonstrated the utility of this simple biofunctionalization process in the context of pathogen sensing via ferrofluids. For our experiments involving microparticle and cell manipulation, we have prepared a citrate stabilized ferrofluid comprised of cobalt-ferrite nanoparticles. We have performed a set of experiments to test our particle manipulation platform using E. coli bacteria. The experiments demonstrated that the bacteria immersed in the ferrofluid could be easily controlled and trapped by changing the direction and the frequency of the excitation.