Monte Carlo Simulation of Nanowires Array Biosensor With AC Electroosmosis

Critically important for electronic biosensing is to reduce detection time that is necessary to sense the capture of biomolecules. The essential factors to study the detection time are the number of captured biomolecules per unit time and the sensitivity of capturing biomolecules. In this paper, we numerically study how ac electroosmosis (ACEO) improves the performance of biosensor unit comprising 400 nanowires by using a Monte Carlo simulation. Note that the number of captured biomolecules per unit time hardly increases if a depleted fluid layer hides the biosensor unit from biomolecules in electrolyte. However, the Monte Carlo simulation tells us that ACEO removes the depleted fluid layer by circulating the electrolyte. This improves the capture efficiency by 4.4 times and the detection speed by 24.8 times. Furthermore, we discuss the scaling effect of nanowires on the sensitivity. As a result, we can more improve the sensitivity if we bury nanowires in a planar oxide layer than wrapping it by an oxide film.