Computational and Applied Math Proseminar

Thursday, January 31, 12:15 p.m. PSA 206

Clemens Heitzinger

Dept Math & Wolfgang Pauli Inst, Univ of Vienna

Multi-scale Modeling and Simulation of Field-Effect Biosensors

Abstract
BioFETs (biologically sensitive field-effect transistors) are field- effect biosensors with semiconducting transducers. Their device structure is similar to a MOSFET, except that the gate structure is replaced by an aqueous solution containing the analyte. The detection mechanism is the conductance modulation of the transducer due to binding of the analyte to surface receptors. The main advantage of BioFETs, compared to currently available technology, is label-free operation.

We first review the recent experiments that provide the motivation for this work. Despite the experimental successes, a quantitative theory to explain the functioning of field-effect biosensors has been missing. The modeling of the sensors is complicated by the fact that a biological and nanoelectronic system have to be considered self- consistently and by the fact that the simulation of the sensors leads to a multi-scale problem.

We then present our solution to the quantitative analysis of BioFETs which is centered around multi-scale models. The technique for solving the multi-scale problem used here is the derivation of interface conditions for the Poisson-Boltzmann equation that include the effects of the quasi-periodic biofunctionalized boundary layer. The multi- scale model enables self-consistent simulation and can be used with any charge transport model. Hence it provides the foundation for understanding the physics of the sensors by continuum models. Finally various simulation results of different devices are compared to measurements to establish the validity of our models and simulations.

For further information please contact: mittelmann@asu.edu