Resonantly excited AlN-based microcantilevers for immunosensing

Abstract

The purpose of this work is to study the performance of resonantly driven microcantilevers excited with a piezoelectric aluminium nitride thin film as a mass sensor for the detection of interactions in the field of immunosensing. Two cantilevers with different width (i.e. 300 and 200 mu m), but constant length and thickness of 300 and 20 mu m were considered. The figures of merit of these structures, such as the mass sensitivity and the limit of mass detection, were determined. According to the results obtained, a cantilever being 300 x 200 mu m(2) in size and a high frequency mode was the best combination to detect antibody/antigen interactions. The previous combination was applied to detect the affinity between rabbit immunoglobulin G (IgG) and the complementary anti-rabbit IgG produced in goat. The binding was registered as a shift of the resonance frequency of the mode under investigation and the correlation between the added mass and the measured shift is analysed.