High sensitivity piezoresistive cantilever design and optimization for analyte-receptor binding

Abstract

The mechanical design and optimization of piezoresistive cantilevers for biosensing applications is studied using finite element analysis. The change of relative resistivity of piezoresistive microcantilevers is analyzed in the presence of the chemical reaction at the receptor surface under the condition of oscillating flow. Chemo-mechanical binding forces have been analyzed in order to understand issues of saturation over the cantilever surface. Furthermore, the optimum design using finite element modeling is achieved by modifying the factors pertaining to the geometry of the microcantilevers under the condition of bio-binding. The introduction of stress concentration regions (SCRs) during cantilever fabrication has been discussed, which greatly enhances the detection sensitivity through increased surface stress. Finally, the optimum SCR modified ‘C’ piezocantilever system for biosensing is designed and the optimal parameters are set for high sensitivity.

Performance Improvisation of Cantilever-type Silicon Micro AccelerationSensors Using Stress Concentration Regions Technique

“…The results of piezoresistive analysis carried out on these structures are also in agreement with stress amplification in comparison to simple flexure obtained in each type of SCR. Sensitivity magnification obtained is in comparison with the results quoted by Gupta 8 , et al, Kassegne 9 , et al, and Yang 10 , et al…”

“…Rectangular and elliptical holes on the cantilever aligned in the longitudinal direction were used as SCRs by Kassegne 9 , et al It was established that SCR helps to increase longitudinal stress more as compared to transverse stress on the cantilever, thus increasing difference between (σ l -σ t ) is desired to get maximise sensitivity. Yang 10 , et al employed techniques of elliptical holes and reduced cantilever width for the formation of SCRs. All these have evolved design principles from their studies on design of cantilever-type sensor with SCR aimed at designing cantilever-type sensor for either scanning probe microscopy application or as a means of detecting molecular adsorption.…”

Enhancing microcantilever capability with integrated AC electroosmotic trapping

“…Recently, there have been intensive research efforts exploring microcantilevers in biosensing applications (Yang et al 2003) because of their impressive mass sensitivity and small size. However, they need to work with highly concentrated fluids due to diffusion process of bioparticles.…”

Micro/nano- particulate fluid manipulation in AC electro-kinetic lab-on-a-chip

“…The parallel plate design has been used to attract particles onto cantilevers for high sensitivity detection [6]. Because particle trapping/concentrating effect is more obvious with the smaller electrode, in our design the metal-coated cantilevers are facing one large electrode (covering a whole fluid chamber), so that particles will aggregate on the cantilevers.…”