Performance characterization of microelectromechanical biosensors using laser Doppler vibrometry

The ability to characterize the motion of micro devices at high frequency with sub-nanometer resolution is key to the development of next generation resonant-based sensor technology.

Micro fabrication processes herald a new generation of healthcare technology where point-of-care sensors promise increased sensitivity at low cost and readout times within minutes.

The highest sensitivity is gained from high quality factor resonating devices in which the addition of mass onto the sensor causes a shift in the resonant frequency of the devices. A novel sensing approach being developed at Newcastle University utilizes degenerate modes of vibration. For a given sensor geometry, a pair of degenerate resonant modes are chosen. In a perfectly fabricated device, symmetry in the system dictates that the frequencies of both modes are identical. With functionalization of the sensor, biomolecules can be immobilized to specific regions of the sensor surface, namely the antinodal position of one of the modes, thereby breaking this symmetry and introducing a split in frequencies between the modes. This split is proportional to the mass addded to the sensor but insensitive to non-specific binding events and temperature fluctuations, making for a robust technology.

https://issuu.com/polytecgmbh/docs/om_infocus_2014_08_2000_e_42332