Development of the microchip-based repeatable immunoassay system for clinical diagnosis

Abstract

A microchip-based semi-automated heterogeneous immunoassay was developed wherein a flow injection-like system and repeatable-use gel were employed. Microfluidics used a pump with highly accurate control of flow rate, two injector valves and a microchip. The results of a system suitability test based on dye injection for microfluidics including a thermal lens microscope as a detector were good. A regeneration buffer for antigen–antibody interaction of brain natriuretic peptide (BNP) was found which did not lose binding activity of the antibody on the gels and integration of such an immunoassay scheme into a semi-automated microfluidics system would facilitate repeated-use heterogeneous immunoassay. Good reproducibility of BNP assay was obtained with the selected regeneration buffer. The concentration of BNP in the range of 0.1–100 pg mL−1 (n = 3) was successfully determined using the system and protocol developed here.