title: The fabrication, characterization and application of aptamer-functionalized Si-nanowire FET biosensors.
abstract: An aptamer-functionalized silicon-nanowire (Si-NW) field effect transistor (FET) biosensor was successfully fabricated, characterized and applied to real-time electrical detection of binding with the target protein for biomedical applications. Surface modifications were carried out using 3-aminopropyl diethoxysilane and succinic anhydride to introduce amine and carboxyl groups onto Si substrates. Anti-thrombin aptamers with 5'-end amine groups were chemically grafted onto the surface-modified Si substrates through amide bond formation. Atomic force microscopic (AFM) analyses confirmed the successful immobilization of anti-thrombin aptamers on Si-NWs and their binding with thrombin samples. The anti-thrombin aptamers bound to Si-NWs through the linker appeared to have a mean height of approx. 4 nm and the thrombin/aptamer complex to have a mean height of approx. 8 nm. Fluorescence micrographs visualized the FITC-labeled thrombin after binding to anti-thrombin aptamers immobilized on Si-NWs. Furthermore, the anti-thrombin Si-NW FET biosensor was successfully applied to the real-time detection of electronic signals during and after binding with a thrombin sample at a concentration of approx. 330 pmol l(-1) and the thrombin in blood samples.
authors.affiliation: Department of Materials Science and Engineering, Pohang University of Science and Technology (POSTECH), Pohang, Kyungbuk, Korea.
authors.forename: Ki Su
authors.initials: KS
authors.lastname: Kim
authors.forename: Hyun-Seung
authors.initials: HS
authors.lastname: Lee
authors.forename: Jeong-A
authors.initials: JA
authors.lastname: Yang
authors.forename: Moon-Ho
authors.initials: MH
authors.lastname: Jo
authors.forename: Sei Kwang
authors.initials: SK
authors.lastname: Hahn
mesh_terms: D052157:Aptamers, Nucleotide / Q000737:chemistry* / Q000378:metabolism; D015374:Biosensing Techniques / Q000379:methods*; D001774:Blood Chemical Analysis / Q000379:methods; D006801:Humans; D018625:Microscopy, Atomic Force; D008856:Microscopy, Fluorescence; D053770:Nanowires / Q000737:chemistry* / Q000648:ultrastructure; D012825:Silicon / Q000737:chemistry*; D013917:Thrombin / Q000737:chemistry / Q000378:metabolism
chemical_list: D052157:Aptamers, Nucleotide; D013917:Thrombin; D012825:Silicon