Microfluidic immunosensor based on stable antibody-patterned surface in PMMA microchip

A sensitive enzyme-linked immunosorbent assay system has been constructed on microfluidic chips. The antibodies (anti-IgG) were encapsulated within the network of Al2O3 sol–gel in the microfluidic channels after the (BMA)x-(MAOPTMS)y copolymer modification. The alumina gel-derived microchannel surface can preserve the bioactivity of antibodies and resist nonspecific adsorption. After the immunoreaction of the antibodies, antigen, and alkaline phosphatase-labeled antibodies, a substrate solution containing 4-aminophenyl phosphate was introduced to the microchannels for end-column electrochemical detection. The microchip immunosensor showed a low detection limit (1 pg mL−1), and broad linear response range (1–500 pg mL−1). The results indicate that this method with high sensitivity and fast response has great potential for clinical and environmental analysis.