Alex Hariz
University of South Australia, Australia
Title: An electrical model for silicon-nanowire electrodes in intracellular signal measurement in biological environments
Biography
Biography: Alex Hariz
Abstract
Measurement of small signals originating from ionic activity inside a biological cell known as action potential, poses a great challenge to biomedical scientists. The electrical signals of the biological cells result from exchange of ions through the cell membrane. The characteristics of action potentials may reveal a great deal of information about the causes and symptoms of abnormal cell behavior. Hence, it is imperative to capture high quality action potentials through the use of nanosensor from within the cell. Recently, developments in silicon nanowires (SiNW) fabrication techniques have demonstrated a great potential for them to be used as nano-electrodes. Large-scale assembly and integration of addressable complementary silicon nanowires arrays have been demonstrated for multiplexed biosensor arrays. The fabrication process resulted in a high-yield, high performance devices arrays for chemical and biological detection. In this paper, we seek to model the electrical interface that is responsible for recording the biological signals. We present electrical equivalent circuits that model the boundary between the biological cell and the nanowire electrode. Impedance measurement curves of nanowires for various sizes of length and diameter have also been presented and discussed in this paper. The impedance graphs show a hyperbolic dependence of resistance on length and diameter of nanowires. This non-linear behavior may be mitigated in software algorithms when interpreting the measured cell signals. We believe that the proposed electrical model will lead to a more accurate characterization of NW biosensor arrays which are now integrated on disposable PCB interfaces. It will potentially evolve the sensor arrays into a controllable and scalable nanowire biosensor platform for clinical and point-of-care diagnostic applications in the near future.