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.
- Tau protein
- Alzheimer's disease
- neurodegenerative screening
Kim, S., Wark, A. W., & Lee, H. J. (2016). Femtomolar detection of Tau proteins in undiluted plasma using surface plasmon resonance. Analytical Chemistry, 88(15), 7793-7799. https://doi.org/10.1021/acs.analchem.6b01825