Rapid and dynamic signal enhancement of bead-based bioassays using a multi-functional optoelectric device

Colloidal particles are broadly used in biochemical applications. Considerable research works have proven particles to be useful carriers in many bead-based bioassays. The increasing use of colloidal systems raises demands for a versatile tool capable of performing multiple functions. To this end, this paper presents a simple optoelectrokinetic method for manipulating particles by simultaneously inducing electrohydrodnamic flow and electrokinetic motions. With carefully tuning the balance between several forces acting on particles, manipulation capabilities including aggregation, translation, sorting, and patterning were achieved. The experimental results showed that the technique is subjected to frequency, electric voltage, laser intensity, and particle size. For a proof of concept, the technique was used to enhance the weak signal of a dilute biotin solution by concentrating streptavidin coated particles. Compared with a ELISA reader, the minimal readout was 100 fold improvement. The demonstration provides a good insight to the future biochemical applications.