Micro-piezoelectric immunoassay chip for simultaneous detection of Hepatitis B virus and α-fetoprotein

In this paper, a piezoelectric diaphragm-based immunoassay chip was developed to simultaneously detect anti-Hepatitis B virus (HBV) and anti-alpha-fetoprotein (AFP). The chip was fabricated by micro-machining technology and consists of eight individual circular sensors with a diameter of 800 μm. Hepatitis B surface antigen (HBsAg), Hepatitis C core antigen (HBcAg) and AFP as the probe molecules were immobilized on different sensing spots on the chip. A solution containing anti-HBsAg and anti-AFP was applied into the reaction chambers in all sensors of the chip, and significant frequency shifts were only observed in the sensors with HBsAg and AFP for immunoassay detection. The fluorescence image further confirmed the successful detection of anti-HBsAg and anti-AFP. The total assay time was less than 2 h. The frequency shift-based calibration curves show a detection limit of 0.1 ng/ml and a dynamic detection range of 0.1–10,000 ng/ml for both anti-HBsAg and anti-AFP, respectively, thus demonstrating that the developed piezoelectric immunoassay chip has potential applications for rapid, specific, sensitive, and multiple detections of HBV.