title: Femtomolar Detection of Tau Proteins in Undiluted Plasma Using Surface Plasmon Resonance.
abstract: The ability to directly detect Tau protein and other neurodegenerative biomarkers in human plasma at clinically relevant concentrations continues to be a significant hurdle for the establishment of diagnostic tests for Alzheimer's disease (AD). In this article, we introduce a new DNA aptamer/antibody sandwich assay pairing and apply it for the detection of human Tau 381 in undiluted plasma at concentrations as low as 10 fM. This was achieved on a multichannel surface plasmon resonance (SPR) platform with the challenge of working in plasma overcome through the development of a tailored mixed monolayer surface chemistry. In addition, a robust methodology was developed involving various same chip control measurements on reference channels to which the detection signal was normalized. Comparative measurements in plasma between SPR and enzyme-linked immunosorbent assay (ELISA) measurements were also performed to highlight both the 1000-fold performance enhancement of SPR and the ability to measure both spiked and native concentrations that are not achievable with ELISA.
authors.affiliation: Department of Chemistry and Green-Nano Materials Research Center, Kyungpook National University , 80 Daehakro, Buk-gu, Daegu-city, 41566, Republic of Korea.
authors.forename: Suhee
authors.initials: S
authors.lastname: Kim
authors.affiliation: WestCHEM, Department of Pure and Applied Chemistry, Technology and Innovation Centre, University of Strathclyde , 99 George Street, Glasgow, G1 1RD, U.K.
authors.forename: Alastair W
authors.initials: AW
authors.lastname: Wark
authors.affiliation: Department of Chemistry and Green-Nano Materials Research Center, Kyungpook National University , 80 Daehakro, Buk-gu, Daegu-city, 41566, Republic of Korea.
authors.forename: Hye Jin
authors.initials: HJ
authors.lastname: Lee
mesh_terms: D000544:Alzheimer Disease / Q000175:diagnosis; D052157:Aptamers, Nucleotide / Q000737:chemistry; D015415:Biomarkers / Q000097:blood; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D020349:Surface Plasmon Resonance; D016875:tau Proteins / Q000097:blood* / Q000737:chemistry
chemical_list: D052157:Aptamers, Nucleotide; D015415:Biomarkers; D016875:tau Proteins