Miniaturized immunoassay microfluidic system with electrokinetic control

A portable heterogeneous immunoassay system is presented in this paper. It consists of a poly(dimethylsiloxane) (PDMS) based microfluidic chip as the immunoreactor, a miniaturized programmable high voltage sequencer as the power supply and the flow controller, and a laser-optical fiber fluorescence detection module as the signal reader. The operation of this immunoassay system is automatic. The sequential reagent dispensing and washing processes are controlled by the programmable sequencer. The reagent consumption was only 12 μL and the assay time was only 26 min. The detection limit for Escherichia coli O157:H7 bacterial antigen with this miniaturized system was 0.3 ng/μL, lower than that obtained using fluorescence microscope in previous studies.