title: Label-free electrochemical diagnosis of viral antigens with genetically engineered fusion protein.
abstract: We have developed a simple electrochemical biosensing strategy for the label-free diagnosis of hepatitis B virus (HBV) on a gold electrode surface. Gold-binding polypeptide (GBP) fused with single-chain antibody (ScFv) against HBV surface antigen (HBsAg), in forms of genetically engineered protein, was utilized. This GBP-ScFv fusion protein can directly bind onto the gold substrate with the strong binding affinity between the GBP and the gold surface, while the recognition site orients toward the sample for target binding at the same time. Furthermore, this one-step immobilization strategy greatly simplifies a fabrication process without any chemical modification as well as maintaining activity of biological recognition elements. This system allows specific immobilization of proteins and sensitive detection of targets, which were verified by surface plasmon resonance analysis and successfully applied to electrochemical cyclic voltammetry and impedance spectroscopy upto 0.14 ng/mL HBsAg.
authors.affiliation: BioProcess Engineering Research Center, KAIST, 291 Daehak-ro, Yuseong-gu, Daejeon 305-701, Korea. hns0924@kaist.ac.kr
authors.forename: Nam Su
authors.initials: NS
authors.lastname: Heo
authors.forename: Shun
authors.initials: S
authors.lastname: Zheng
authors.forename: Minho
authors.initials: M
authors.lastname: Yang
authors.forename: Seok Jae
authors.initials: SJ
authors.lastname: Lee
authors.forename: Sang Yup
authors.initials: SY
authors.lastname: Lee
authors.forename: Hwa-Jung
authors.initials: HJ
authors.lastname: Kim
authors.forename: Jung Youn
authors.initials: JY
authors.lastname: Park
authors.forename: Chang-Soo
authors.initials: CS
authors.lastname: Lee
authors.forename: Tae Jung
authors.initials: TJ
authors.lastname: Park
mesh_terms: D055910:Antibodies, Immobilized / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D000914:Antibodies, Viral / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D000956:Antigens, Viral / Q000032:analysis* / Q000737:chemistry / Q000235:genetics / Q000276:immunology; D015374:Biosensing Techniques / Q000295:instrumentation* / Q000379:methods*; D055664:Electrochemical Techniques / Q000295:instrumentation* / Q000379:methods*; D006046:Gold / Q000737:chemistry; D006515:Hepatitis B virus / Q000276:immunology; D010455:Peptides / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D015202:Protein Engineering; D011993:Recombinant Fusion Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D057127:Single-Chain Antibodies / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D020349:Surface Plasmon Resonance
chemical_list: D055910:Antibodies, Immobilized; D000914:Antibodies, Viral; D000956:Antigens, Viral; D010455:Peptides; D011993:Recombinant Fusion Proteins; D057127:Single-Chain Antibodies; D006046:Gold
keywords: Gold-binding polypeptide; electrochemical analysis; fusion protein; hepatitis B virus