Water-proof ‘μ-diving suit’ dressed on resonant biochemical sensor for online detection in solution

This paper reports a new method to ensure resonant micro-sensor long-time resonating in solution for real-time biochemical sensing/analysis. By designing a water-proof `diving-suit´ for the cantilever resonator and an anti-leakage narrow `slit´ to free the cantilever vibration, only the sensing-region of the cantilever contacts to analyte solution, while the other parts are remained in air to keep free-resonance. With this `μ-diving suit´ design, the resonant cantilever with electrothermal driven and piezoresistive frequency readout integrated can achieve a Q factor of 17 in water. With specific sensing-material loaded at the sensing-region, the cantilever sensor experimentally realizes liquid-phase real-time detection to ppb-level organophosphorous pesticide of acephate.