Authors: W. Maki, N. Mishra, M. Fellegy, E. Cameron, G. Maki
Affilation: University of Idaho, United States
Pages: 681 - 684
Keywords: surface modification, nanowire, silicon oxide film, nano-surface
Nano-scale Field Effect Transistor based devices (nano-FETs) have shown great promise in bio-molecular detection. The advantages of using electronic nano-devices verses using conventional bio-detection methods are: direct detection without labeling, ultra-sensitivity without amplification and simple device implementation without expensive equipment. However, immobilization of bio-molecules on nano-scaled devices is a challenge. We investigated methods for immobilizing oligonucleotide and peptide nucleic acid (PNA) on nanowire devices. Oligonucleotide and PNA were covalently linked on the nanowire surface which is covered by 1-2 nm native silicon oxide. Standard silanization chemistry combined with bi-functional linker approach was used in the immobilization process. Low concentration acetic acid solution was used to wash the silanized surface which reduced the thickness of the silane layer under 4 nm. This allows negatively charged target nucleic acids much closer to the nanowire, and increases detection sensitivity. Streptavidin-Alkaline phosphotase (SA-AP) conjugate was used as indicator to confirm immobilized oligonucleotide. PNA immobilization was confirmed by hybridization with a biotin labeled oligonucleotide with complimentary sequence, and detected by SA-AP conjugate.