Optimized Creation of Monolayers for Parallel Readout of Bead-Based Assays

Grumann, M.; Dobmeier, Michael; Schippers, Patric; Brenner, Thilo; Zengerle, Roland; Ducrée, Jens; Kuhn, Claus; Fritsche, M.

doi:10.1007/978-3-642-18727-8_17

Cited by 1 publication

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“…Bead-based platforms offer a high degree of versatility because many kinds of beads with a variety of functionalizations are available. Different approaches are possible to immobilize beads on a chip, e.g., mechanical barriers [3,4], magnetic contraptions [5], EOF and pressure-driven counterflow for contactless trapping of beads in vortices generated at diffuser-nozzle elements [6], and retention by dielectrophoresis (DEP) either in contactless field cages using negative DEP [7] or at electrode edges using positive DEP [8]. Walt et al [9] presented a bead-based assay concept using color-encoded beads similar to the ones known from the Luminex multiplexed flow cytometry assays [10].…”

Section: Introductionmentioning

confidence: 99%

Fast immobilization of probe beads by dielectrophoresis-controlled adhesion in a versatile microfluidic platform for affinity assay

et al. 2005

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The use of probe beads for lab-on-chip affinity assays is very interesting from a practical point of view. It is easier to handle and trap beads than molecules in microfluidic systems. We present a method for the immobilization of probe beads at defined areas on a chip using dielectrophoresis (DEP)-controlled adhesion. The method is fast, i.e., it takes between 10 and 120 s--depending on the protocol--to functionalize a chip surface at defined areas. The method is versatile, i.e., it works for beads with different types of probe molecule coatings. The immobilization is irreversible, i.e., the retained beads are able to withstand high flow velocities in a flow-through device even after the DEP voltage is turned off, thus allowing the use of conventional high-conductivity analyte buffers in the following assay procedure. We demonstrate the on-chip immobilization of fluorescent beads coated with biotin, protein A, and goat-antimouse immunoglobulin G (IgG). The number of immobilized beads at an electrode array can be determined from their fluorescence signal. Further, we use this method to demonstrate the detection of streptavidin and mouse IgG. Finally, we demonstrate the feasibility of the parallel detection of different analyte molecules on the same chip.

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