title: Modified screen printed electrode for development of a highly sensitive label-free impedimetric immunosensor to detect amyloid beta peptides.
abstract: Alzheimer's disease (AD) is a fatal neurodegenerative disease affecting approximately 26 million people world-wide, and the number is increasing as life expectancy increases. Since the only reliable diagnosis for the pathology is histochemical post-mortem examination, there is a rather urgent need for reliable, sensitive and quick detection techniques. Amyloid beta, being one of the established and widely accepted biomarkers of AD is a target biomolecule. Herein, we present fabrication of a labelless impedimetric amyloid beta immunosensor on carbon DEP (disposable electrochemical printed) chip. Three types of amyloid β impedimetric immunosensors were fabricated in a systematic step-wise manner in order to understand the effects that each surface modification chemistry had on detection sensitivity. We found that compared to a bare electrode, surface modification through formation of SAM of AuNPs increased sensitivity by approximately three orders of magnitude (LoD from 2.04 μM to 2.65 nM). A further modification using protein G, which helps orientate antibodies to an optimum position for interaction with antigen, lowered the LoD further to 0.57 nM. We have demonstrated that the presence of one of the most abundance proteins in biological fluids, bovine serum albumin (BSA), did not interfere with the sensitivity of the sensor. Since the DEP chips are disposable and the detection platform label-free, the developed sensor is relatively fast and cheap. These methods could easily be applied for detection of other antigens, with selection of the detection platform based on the desired for sensitivity.
authors.affiliation: School of Materials Science, Japan Advanced Institute of Science and Technology (JAIST), 1-1 Asahidai, Nomi, Ishikawa, 923-1292, Japan; School of Engineering Physics, Hanoi University of Science and Technology (HUST), No.1 Dai Co Viet, Hai Ba Trung, Hanoi, Viet Nam.
authors.forename: Truong T N
authors.initials: TT
authors.lastname: Lien
authors.affiliation: School of Materials Science, Japan Advanced Institute of Science and Technology (JAIST), 1-1 Asahidai, Nomi, Ishikawa, 923-1292, Japan.
authors.forename: Yuzuru
authors.initials: Y
authors.lastname: Takamura
authors.affiliation: Department of Applied Physics, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka, 565-0871, Japan.
authors.forename: Eiichi
authors.initials: E
authors.lastname: Tamiya
authors.affiliation: School of Materials Science, Japan Advanced Institute of Science and Technology (JAIST), 1-1 Asahidai, Nomi, Ishikawa, 923-1292, Japan; Department of Biochemical Science and Technology, Faculty of Agriculture, Kagoshima University, Korimoto-1-21-24, Kagoshima City, Kagoshima, 890-0065, Japan. Electronic address: munde@agri.kagoshima-u.ac.jp.
authors.forename: Mun'delanji C
authors.initials: MC
authors.lastname: Vestergaard
mesh_terms: D016229:Amyloid beta-Peptides / Q000032:analysis* / Q000276:immunology; D000818:Animals; D000906:Antibodies / Q000276:immunology / Q000378:metabolism; D001426:Bacterial Proteins / Q000737:chemistry / Q000378:metabolism; D015374:Biosensing Techniques; D002244:Carbon / Q000737:chemistry; D002417:Cattle; D055664:Electrochemical Techniques; D004566:Electrodes; D006046:Gold / Q000737:chemistry; D053768:Metal Nanoparticles / Q000737:chemistry; D010169:Palmitic Acids / Q000737:chemistry; D012710:Serum Albumin, Bovine / Q000737:chemistry
chemical_list: C450319:16-mercaptohexadecanoic acid; D016229:Amyloid beta-Peptides; D000906:Antibodies; D001426:Bacterial Proteins; C034284:IgG Fc-binding protein, Streptococcus; D010169:Palmitic Acids; D012710:Serum Albumin, Bovine; D002244:Carbon; D006046:Gold
keywords: Amyloid beta (Aβ); Disposable electrochemical printed (DEP) chip; Electrochemical impedance spectroscopy (EIS); Immunosensor; Screen-printed electrode (SPE)