Realization of a DNA biosensor using inverted Lamb wave MEMS resonator based on ZnO/SiO₂/Si/ZnO membrane

A novel technique based on inverted Lamb wave MEMS resonator has been exploited for the realization of a DNA biosensor. Zinc oxide based Lamb wave MEMS resonator in the inverted configuration of ZnO/SiO₂/Si/ZnO is fabricated for label free and efficient detection of Neisseria meningitidis, responsible for bacterial meningitis. Meningitis remains a devastating endemic in sub-Saharan Africa. Its early detection can prevent the spread and its lethal complications. The developed biosensor shows a very high sensitivity of 310 Hz(ngμl^-1)^-1 and very low detection limit of 82 pgμl^-1 for symmetric mode of the Lamb wave device while the antisymmetric mode shows a sensitivity of 202 Hz(ngμl^-1)^-1 and the limit of detection of 84 pgμl^-1. This very high sensitivity and very low detection limit of the Lamb wave resonator can be attributed to very high mass loading effect on the membranous structure of Lamb wave device, unlike the bulk substrate based devices. The indigenously developed MEMS based inverted Lamb wave biosensor shows high selectivity, long shelf life and good reproducibility. The ease of operation, low processing time and possibility of wireless integration of the of the Lamb wave DNA sensor paves a path towards the promising application in the field of meningitidis detection. The use of fabricated biosensor can be extended to other viral and bacterial detection applications as well.