title: Electrical signaling of enzyme-linked immunosorbent assays with an ion-sensitive field-effect transistor.
abstract: Optical laboratory-based immunoassays, such as enzyme-linked immunosorbent assay (ELISA) give a high sensitivity and specificity of various fatal diseases. However, these assays are no longer efficient in on-spot diagnostics of wide-spreading and contagious infections. At this point in time, portable and handhold devices play a pivotal role in infectious diseases with quick diagnostics at or near the site of the disease propagation. In this paper, we demonstrated a novel electrical immunoassay of ELISA that was not based on optical signaling but on electrical signaling. This was done by combining an ion-sensitive field-effect transistor (ISFET) with ELISA. By harnessing the catalytic reaction of alkaline phosphatase that precipitated silver particles, we effectively overcame the chronic Debye screening length issue of the ISFET. Ultimately, small signal ranging from 1 pg/mL to 10 ng/mL was immensely amplified with the ALP label, regardless of buffer conditions. The sensor platform herein surpassed a sensing capability of conventional ELISA that is considered to have a LOD on the order of ~1 ng/mL. The results were compared with those of horseradish peroxidase label, which is generally used for optical analyses in ELISA. Our newly developed ISFET-based portable sensor holds a large potential for point-of-care tools in a variety of diseases, without being limited by the need for expensive equipment such as spectrophotometers.
authors.affiliation: Biomedical Research Institute, Korea Institute of Science and Technology (KIST), 5 Hwarangno 14-gil, Seongbuk-gu, Seoul 136-791, Korea; AMC-KIST Translational Research Center (TRC), Asan Medical Center, 88 Olympic-ro 43-gil, Songpa-gu, Seoul 138-736, Korea.
authors.forename: Hyun-June
authors.initials: HJ
authors.lastname: Jang
authors.affiliation: Department of Nano Manufacturing Technology, Nano Convergence Mechanical Systems Research Division, Korea Institute of Machinery and Materials, 156 Gajeongbuk-Ro, Yuseong-Gu, Daejeon 305-343, Korea.
authors.forename: Junhyoung
authors.initials: J
authors.lastname: Ahn
authors.affiliation: Department of Chemistry, Gwangju Institute of Science & Technology, 123 Chemdangwagi-Ro, Buk-Gu, Gwangju 500-712, Korea.
authors.forename: Min-Gon
authors.initials: MG
authors.lastname: Kim
authors.affiliation: Research Center of Integrative Cellulomics, Korea Research Institute of Bioscience and Biotechnology, 125 Gwahak-Ro, Yuseong-Gu, Daejeon 305-806, Korea.
authors.forename: Yong-Beom
authors.initials: YB
authors.lastname: Shin
authors.affiliation: Biomedical Research Institute, Korea Institute of Science and Technology (KIST), 5 Hwarangno 14-gil, Seongbuk-gu, Seoul 136-791, Korea; AMC-KIST Translational Research Center (TRC), Asan Medical Center, 88 Olympic-ro 43-gil, Songpa-gu, Seoul 138-736, Korea.
authors.forename: Minhong
authors.initials: M
authors.lastname: Jeun
authors.affiliation: Department of Electronic Materials Engineering, Kwangwoon University, 20 Gwangun-ro, Nowon-gu, Seoul 139-701, Korea. Electronic address: chowj@kw.ac.kr.
authors.forename: Won-Ju
authors.initials: WJ
authors.lastname: Cho
authors.affiliation: Biomedical Research Institute, Korea Institute of Science and Technology (KIST), 5 Hwarangno 14-gil, Seongbuk-gu, Seoul 136-791, Korea; AMC-KIST Translational Research Center (TRC), Asan Medical Center, 88 Olympic-ro 43-gil, Songpa-gu, Seoul 138-736, Korea. Electronic address: kwanhyi@gmail.com.
authors.forename: Kwan Hyi
authors.initials: KH
authors.lastname: Lee
mesh_terms: D000469:Alkaline Phosphatase / Q000737:chemistry; D015374:Biosensing Techniques / Q000379:methods*; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods*; D004867:Equipment Design; D006735:Horseradish Peroxidase / Q000737:chemistry*; D006801:Humans; D017736:Ion-Selective Electrodes; D007477:Ions / Q000737:chemistry
chemical_list: D007477:Ions; D006735:Horseradish Peroxidase; D000469:Alkaline Phosphatase
keywords: ALP; ELISA; ISFET; Immunosensor; Point-of-care device