Micro-machined piezoelectric membrane-based immunosensor array

This paper reports a micro-machined piezoelectric membrane-based biosensor array for immunoassay. Goat immunoglobulin G (IgG) and HBsAg were immobilized as the probe molecules on the square piezoelectric membranes of the sensors that have dimensions of 3.5 μm × 500 μm × 500 μm. Due to the mass sensitive nature of these sensors, their resonant frequencies were depressed after the anti-goat IgG or anti-HBsAg was captured by the goat IgG or HBsAg. The resonant frequencies of the sensors were measured by an impedance analyzer. The experimental results demonstrate that the measured frequency change varies from 100 to 700 Hz, and the mass sensitivity of the device is estimated to be about 6.25 Hz/ng. A near linear relationship between the frequency change and the concentration of goat IgG was obtained, and the mass of the attached anti-goat IgG was calculated. The preliminary results discussed in this work indicate that the micro-machined piezoelectric membrane-based biosensor has a potential application as an immunosensor.