title: Trapping single molecules by dielectrophoresis.
abstract: We have trapped single protein molecules of R-phycoerythrin in an aqueous solution by an alternating electric field. A radio frequency voltage is applied to sharp nanoelectrodes and hence produces a strong electric field gradient. The resulting dielectrophoretic forces attract freely diffusing protein molecules. Trapping takes place at the electrode tips. Switching off the field immediately releases the molecules. The electric field distribution is computed, and from this the dielectrophoretic response of the molecules is calculated using a standard polarization model. The resulting forces are compared to the impact of Brownian motion. Finally, we discuss the experimental observations on the basis of the model calculations.
authors.affiliation: Department of Molecular Bioanalytics and Bioelectronics, Fraunhofer Institute for Biomedical Engineering, 14558 Nuthetal, Germany.
authors.forename: Ralph
authors.initials: R
authors.lastname: Hölzel
authors.forename: Nils
authors.initials: N
authors.lastname: Calander
authors.forename: Zackary
authors.initials: Z
authors.lastname: Chiragwandi
authors.forename: Magnus
authors.initials: M
authors.lastname: Willander
authors.forename: Frank F
authors.initials: FF
authors.lastname: Bier
mesh_terms: D004574:Electromagnetic Fields; D004586:Electrophoresis / Q000379:methods*; D010799:Phycoerythrin / Q000737:chemistry*; D013050:Spectrometry, Fluorescence
chemical_list: D010799:Phycoerythrin