Regensburg 2007 – scientific programme

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BP: Fachverband Biologische Physik

BP 26: Poster Session II

BP 26.10: Poster

Thursday, March 29, 2007, 17:00–19:30, Poster B

Observation of nanoparticle uptake in living cells by single particle tracking — •Nadia Ruthardt¹, Karla de Bruin¹, Kevin Braeckmans², Ernst Wagner³, and Christoph Bräuchle¹ — ¹Department Chemie und Biochemie and Center for NanoScience (CeNS), Ludwig-Maximilians Universität München, Butenandtstr. 5-13, D-81377 München, Germany — ²Laboratory of General Biochemistry and Physical Pharmacy, Faculty of Pharmaceutical Sciences, Ghent University, Harelbekestraat 72, B-9000 Ghent, Belgium — ³Pharmaceutical Biology-Biotechnology, Department of Pharmacy, Ludwig-Maximilians-Universität, Butenandtstr. 5-13, D-81377 München, Germany

Nanoparticles consisting of DNA complexed by cationic polymers (polyplexes) can be used as non-viral vectors for gene transfer into cells and are an important candidate for gene therapy. To enhance cell targeting, PEI polyplexes with a PEG shield were functionalized with EGF (epidermal growth factor) for specific binding to the EGF receptor on the cell surface. By using highly sensitive fluorescence wide-field microscopy, single particle tracking was performed to generate trajectories of the uptake dynamics into living cells. Typically, three types of particle motion were observed: (1) a phase of immobility and slight drift; (2) a diffusive movement in the cytoplasm; and (3) directed motion along microtubules. EGF+ particles are internalized up to 100% within 10-15 minutes whereas PEI particles show internalization to a much lesser extend.