Numerical study of in situ preconcentration for rapid and sensitive nanoparticle detection

Abstract

This paper presents a numerical study of a preconcentrator design that can effectively increase the binding rate at the sensor in a real time manner. The particle enrichment is realized by the ac electrothermal ͑ACET͒ effect, which induces fluid movement to carry nanoparticles toward the sensor. The ACET is the only electrical method to manipulate a biological sample of medium to high ionic strength ͑Ͼ0.1 S / m, e.g., 0.06ϫ phosphate buffered saline͒. The preconcentrator consists of a pair of electrodes striding over the sensor, simple to implement as it is electrically controlled. This preconcentrator design is compatible and can be readily integrated with many types of micro-to nanosensors. By applying an ac signal over the electrodes, local vortices will generate a large velocity perpendicular to the reaction surface, which enhances transport of analytes toward the sensor. Our simulation shows that the binding rate at the sensor surface is greatly enhanced. Our study also shows that the collection of analytes will be affected by various parameters such as channel height, inlet velocity, and sensor size, and our results will provide guidance in optimization of the preconcentrator design.

Transient Convection, Diffusion, and Adsorption in Surface-Based Biosensors

“…4 From a theoretical viewpoint, similar physics also occur in other systems, such as protein microarrays. 5 Theoretical research, related to biosensor applications, typically attempts to include novel mechanisms, such as the ac electrothermal (ACET) effect, 6 or aims at developing analytical and semianalytical models for better data interpretation. 7,8 Surface plasmon resonance (SPR) spectroscopy, in particular, is an advanced optical sensing method that enables label free monitoring of macromolecular interactions.…”

Rapid and sensitive detection of small biomolecule by capacitive sensing and low field AC electrothermal effect

“…The metal casing around the electrode chip is about 4 mm (L) x 2.5 mm (W) x 1 mm (H) = 10 µL, serving as a microchamber for sample solutions. The microchambers in both cases are sufficiently high, so that electric fields and ACEK effects can fully develop, as shown by numerical simulation [47].…”

Coupled Gas Flow, Diffusion and Reaction in a ppb-level SnO2-NiO Formaldehyde Sensor System

“…While transport modeling has been regularly undertaken inside sensor films [6], the coupled effects of external gas phase transport delivering analyte have not been simultaneously considered. A number of recent papers exist which study the transport of analyte in the external gas phase in a sensing system with preconcentraion, and which provide comment on how the flow fields and other associated parameters would be expected to influence sensor behaviour [18][19][20][21]. One paper was found where the flow field was simulated which included a sensor surface source term for analyte, thereby estimating the sensor-gas phase interface concentration of analyte in a steady state flow field [21].…”