Piezoresistive microcantilever

Deflagration experiments were conducted only for TNT vapors. For deflagration experiments we have used a piezoresistive microcantilever the piezoresistive... 

Pinnadnwage L. A., Yi D., Thnndat T. G., and Hawk J. E., Non-optical explosive sensor based on two-track piezoresistive microcantilever, United States Patent and Trademark Office Pre-Grant Publication, February 2006, pat no US20060032289. 

The deflections of a microcantilever can be measured with sub-Angstrom resolution using current techniques perfected for die AFM, such as optical reflection, piezoresistive, capacitance, and piezoelectric detection methods. One great advantage of flie cantilever technique is diat five resonance response parameters (resonance fiequency, phase, anqilitude, Q-flictor, and deflection) can be simultaneously detected. 

Among voltammetric MEMS biosensors, a piezoresistive microcantilever is a good example. The general configuration of a piezoresistive microcantDever sensor is shown in Fig. 4. The stress caused by biochemical reactions is concentrated on the surface of the microcantUever. Piezoresistors are usually placed on the microcantilever to the rim, where the stress is maximal. When the microcantilever is bent due to biochemical reaction, the resistivity of the microcantilever is changed. And by measuring the change, the concentration of the biochemical is detected [7]. 

MEMS-Based Biosensor, Fig. 4 Schematic and cross-sectional view of a piezoresistive microcantilever [7]... 

Signal transduction from microcantilevers is based on optical, piezoelectric, and piezoresistive methods. Optical transduction is based on measurement of displacement of reflected light from the surface of microcantilever with the help of a position-sensitive photodetector [95]. However, this is not suitable for POC devices, because a larger path length might be required, which precludes portable instrumentation. Piezoelectric and piezoresistive detection involves integration of a piezoresistive (poly silicon) or piezoelectric material, respectively, on the microcantilever. In this case, the instrumentation can obviously be miniaturized. However, the requirement for a mechanically stable environment, difficulty in functionalization of a large number of cantilevers at the same time, fabrication losses, etc. are obstacles to commercialization of devices based on microcantilevers as POC products. 

The resistive-type sensors measure strain-related mechanical properties such as strain, force, acceleration, and pressure-utilizing piezoresistive properties of sensitive film resistors [2,14,38,39]. These sensors are also incorporated as biosensors for detecting biomolecules. The electrode configuration is the same as in electrochemical transducers, but it measures the change of resistance when biomolecules interact with the biologically sensitive elements [2]. The piezoresistive microcantilever sensors are also extensively studied for biosensing. The piezoresistive sensors. 

Resistive Resistance Voltage Piezoresistive microcantilever DNA detection [38]... 

Resistance Voltage Piezoresistive microcantilever Herpes simplex -1 virus E. coli bacteria [14]... 

M.S. Arefin, T.L. Porter, An ac electroosmosis device for the detection of bioparticles with piezoresistive microcantilever sensors. Journal of Applied Physics 111 (2012)... 

Microcantilever, which owes its existence to atomic force microscopy, is based on the principle that binding the analyte to a biological recognition layer on the microcantilever induces surface stress, resulting in nanomechanical motion that can be measured optically or by a piezoresistive readout system (Rackus et al., 2015). 

Figure 31 Sensor transducers based on mechanical work on responsive hydrogel, (a) Fiber BFtAGG grating sensor, (b) microcantilever, (c) piezoresistive bending plate sensor, and (d) capacitive bending plate sensor. Reprinted from Richter, A, Paschew, G. Klatt, S. etal. Sensors 2008, 8,561-581. ...

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