title: Fabrication of stable antibody-modified field effect transistors using electrical activation of Schiff base cross-linkages for tumor marker detection.
abstract: In this paper, we present a method of fabricating a rigid antibody-immobilized surface using electric activation of a glutaraldehyde (GA)-modified aminopropylsilyl surface for stable antibody-modified field effect transistors (FETs). Electric activation of the GA-modified gate surface of the FET reduces Schiff bases, which are easily hydrolyzed and collapsed, formed between GA and 3-aminopropyltriethoxysilane, resulting in preventing the immobilized antibodies from desorbing from the surface. The lack of Raman peaks that could be assigned to a Schiff base after the electrical activation of the GA-modified surface indicated that the electric activation had reduced the Schiff base. The use of the antibody-modified FETs has three advantages for the detection of antigens: increased sensitivity, distinct recognition ability, and improved reproducibility. A tumor marker, alpha-fetoprotein (AFP), was quantitatively detected up to a concentration of 10 ng/mL using the antibody-modified FET. The detection ability of the FET accomplished a cutoff value of hepatic cancer. The quantitative detection of AFP in a solution with contaminating proteins was also demonstrated. This electric activation method is applicable to other antibody-modified FETs.
authors.affiliation: Department of Applied Chemistry, Faculty of Science and Engineering, Waseda University, Okubo 3-4-1, Shinjuku-ku, Tokyo 169-8555, Japan.
authors.forename: Sho
authors.initials: S
authors.lastname: Hideshima
authors.forename: Ryosuke
authors.initials: R
authors.lastname: Sato
authors.forename: Shigeki
authors.initials: S
authors.lastname: Kuroiwa
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Osaka
mesh_terms: D000912:Antibodies, Neoplasm / Q000737:chemistry / Q000276:immunology; D014408:Biomarkers, Tumor / Q000032:analysis*; D015374:Biosensing Techniques / Q000295:instrumentation*; D003217:Conductometry / Q000295:instrumentation*; D003432:Cross-Linking Reagents / Q000737:chemistry; D004867:Equipment Design; D019544:Equipment Failure Analysis; D006062:Gonadotropins / Q000032:analysis* / Q000737:chemistry / Q000276:immunology; D006801:Humans; D008113:Liver Neoplasms / Q000175:diagnosis / Q000378:metabolism*; D012545:Schiff Bases / Q000737:chemistry; D014173:Transistors, Electronic; D014407:Tumor Cells, Cultured; D000509:alpha-Fetoproteins / Q000032:analysis* / Q000737:chemistry / Q000276:immunology
chemical_list: D000912:Antibodies, Neoplasm; D014408:Biomarkers, Tumor; D003432:Cross-Linking Reagents; D006062:Gonadotropins; D012545:Schiff Bases; D000509:alpha-Fetoproteins