Improved biomarker quantification of silicon nanowire field-effect transistor immunosensors with signal enhancement by RNA aptamer: Amyloid beta as a case study

Cao An Vu, Wen Yih Chen, Yuh Shyong Yang, Hardy Wai Hong Chan

Research output: Contribution to journalArticlepeer-review

9 Scopus citations

Abstract

Quantifying proteins at ultra-low levels in high ionic-strength solutions by silicon nanowire field-effect transistor (SiNWFET) immunosensors is critically hindered due to the limited Debye length, charge distributions and uncontrollable orientations of protein molecules on the NW surfaces. In this study, we propose a novel strategy to overcome this issue by employing aptamer as bio-amplifier for different types of SiNWFET immunosensors to quantify Amyloid Beta (Aβ) 1-42, a biomarker for early-stage diagnosis of Alzheimer disease (AD) with ultra-low level in human serum (HS), as a representative target. Our method, presented for the first time, exhibits an outstanding performance in combination with mSAM-SiNWFET immunosensors (designed by integrating SiNWFET as transducer, mouse antibody as bio-receptor, and mixed self-assembled monolayers (mSAMs) for biofouling resistance) to sense Aβ 1-42 down to 100 fg/mL in HS, the lowest level achieved in comparison with the most advanced sensing technologies for Aβ 1-42. The empirical data also reveal that varied concentrations of Aβ 1-42 in diverse high ionic-strength environments (150 mM BTP and HS) express good linear relationship with signal amplified by aptamer. This novel approach is therefore potentially applied for early-stage diagnosis of AD and other clinical trials of biomarkers with ultra-low content in blood.

Original languageEnglish
Article number129150
JournalSensors and Actuators, B: Chemical
Volume329
DOIs
StatePublished - 15 Feb 2021

Keywords

  • Alzheimer disease
  • Amyloid beta 1-42
  • Aptamer
  • Mixed self-assembled monolayer
  • Signal enhancement
  • Silicon nanowire field-effect transistor immunosensor

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