Patent ID: 8480956

Claim:
A laterally oscillating gravimetric sensing device being embeddable inside a micro-fluidic channel to detect analytes and/or biological entities by measuring the change of mass attached on its surface, comprising: a hydrophobic polymer coated proof-mass ( 1 ) that can be placed inside a microfluidic channel where the hydrophobic polymer prevents direct contact of proof-mass to the liquid and facilitates electrical actuation and read-out of the proof-mass; comb-fingers fixed to the proof mass ( 2 ) coated with the same hydrophobic polymer for electrical read-out and actuation of the proof mass where the hydrophobic polymer prevents both direct contact of conductive comb-fingers to the liquid and filling of the liquid between comb-fingers for keeping quality factor of oscillation high inside the liquid environment; stationary electrodes ( 5 ) coated with the said hydrophobic polymer for electrical read-out and actuation of the proof mass where the hydrophobic polymer prevents both direct contact of the stationary electrodes ( 5 ) to the liquid and filling of the liquid between comb-fingers and stationary electrodes for keeping the quality factor of oscillation high inside the liquid environment; and folded spring beams ( 3 ) connecting the proof mass ( 1 ) to mechanical ground ( 4 ) where this structure minimizes the dependence of the output frequency shift to the mass attachment location.