Concentration-enhanced rapid detection of human chorionic gonadotropin as a tumor marker using a nanofluidic preconcentrator

Here, we report a new method of concentration-enhanced binding kinetics for a rapid immunoassay screening test on a gold surface in a poly(dimethylsiloxane) (PDMS) microfluidic chip format. The use of alkylthiolate self-assembled monolayers on gold surfaces of a PDMS-glass microchip resulted in accelerated binding kinetics at an electrokinetic trapping zone. We used human chorionic gonadotropin (hCG) as a model analyte for a tumor marker to demonstrate the potential ability of dynamic preconcentrating operation in serum using 1D planar gold surface and demonstrated concentration-enhanced binding kinetics by 500-fold. The preconcentration of cy3 labeled streptavidin onto biotinylated Au surface also revealed that the binding kinetics of the protein were linearly proportional to the concentration profile of the preconcentration plug. We showed rapid detection of hCG in the clinical range with a shorten total assay time of 15 min. The enhanced binding kinetics between hCG antigen-antibody via preconcentration showed good feasibility for use in a rapid immunoassay screening test.