Fabrication of N-Type Silicon Nanowire Biosensor for Sub-10-Femtomolar Concentration of Immunoglobulin
A simple fabrication process of an n-type silicon nanowire (SiNW) biosensor for sub-10 femtomolar (fM) concentration immunoglobulin detection was presented in this work. The SiNWs with different widths of 80-190 nm were fabricated using electron beam lithography and reaction ion etching techniques. The electrical characteristics of SiNWs with various widths were measured. And it can be observed that thin SiNW has high resistance, which is in agreement with electrical resistance theory. Furthermore, the surface of the fabricated SiNW was functionalized by 3-aminopropyltriethoxysilane for making the biosensor device to detect the binding of immunoglobulin G (IgG) molecules. The responsivity of the biosensor was investigated by observing electrical performance in response due to IgG with various concentration from 6 fM to 600 nanomolar (nM). The resistance changing ratio based on the current voltage (I-V) characteristics was analyzed and it increased with increasing of the IgG concentration. As a result, it demonstrated that the n-type SiNW biosensor has the ability to detect the IgG molecules with low concentration of 6 fM.
T. Tomoya et al., "Fabrication of N-Type Silicon Nanowire Biosensor for Sub-10-Femtomolar Concentration of Immunoglobulin", Key Engineering Materials, Vol. 790, pp. 28-33, 2018