Dielectrophoretic coassembly of binary colloidal mixtures in AC electric fields.

We report the novel use of dielectrophoresis (DEP) for fabricating a new class of composite structures composed of binary mixtures of micrometer-sized colloidal particles. Latex-latex and latex-yeast cells have been coassembled in a combinatorial manner into one- (1D) and two-dimensional (2D) architectures in spatially varying external alternating current (AC) electric fields using two different electrode geometries. The effects of voltage, frequency, particle size, particle concentration, and particle type are investigated in detail to determine how the relative polarizabilities of the particles can be tuned to influence the overall coassembly process. Our observations reveal key differences in the latex-latex and latex-yeast cell assembly behavior especially in the case of 2D structure formation arising mainly due to the intrinsically high polarizability and polydispersity of the cells. This study is useful for making a potpourri of new hybrid structures with advanced functionalities for photonic and biosensing applications.