Detection of the tau protein in human serum by a sensitive four-electrode electrochemical biosensor

Abstract

This study presents a novel approach based on a four-electrode electrochemical biosensor for the detection of tau protein -one of the possible markers for the prediction of Alzheimer's disease (AD). The biosensor is based on the formation of stable antibody-antigen complexes on gold microband electrodes covered with a layer of a self-assembled monolayer and protein G. Antibodies were immobilized on the gold electrode surface in an optimal orientation by protein G interaction. Electrochemical impedance spectroscopy was used to analyze impedance change, which revealed a linear response with increasing tau concentrations. The assay is fast (<1 h for incubation and measurement) and very sensitive. The limit of quantification for the full-length 2N4R tau protein is 0.03 pM, a value unaltered when the assay was processed in bovine serum albumin or human serum. This technology could be adapted for the detection of other biomarkers to provide a multiple assay to identify AD progression in a point of care setting.

Development of a Label-Free Electrochemical Aptasensor for the Detection of Tau381 and its Preliminary Application in AD and Non-AD Patients’ Sera

“…The limit of detection (LOD), calculated at a signal/noise ratio of 3, was found to be 0.70 pM. The proposed label-free aptasensor showed a slightly higher detection limit compared to that of sandwich-based tau381 immunosensors [14,20].…”

“…Thus, aptamers are particularly attractive in the field of clinical testing and electrochemical sensing [11,12]. Various biosensor transductions are displayed in Table 1, fluorescence [10], electrochemistry [13,14,15,16], and surface plasmon resonance (SPR) [17,18,19], have been developed for tau biosensors. Until now, the electrochemical transduction was associated with anti-tau antibody as a recognition element.…”

Real-Time Tau Protein Detection by Sandwich-Based Piezoelectric Biosensing: Exploring Tubulin as a Mass Enhancer

“…Although affinity sensing based on QCM transduction has been successfully applied to aggregation kinetic studies [ 15 ] and AD clinical diagnostics [ 16 , 17 ] based on amyloid-β detection, to our best knowledge its application to tau protein detection has not been reported so far. Contrarily, some encouraging findings with electrochemical [ 18 , 19 , 20 ] and conventional and/or localized SPR-based [ 14 , 21 , 22 ] have been reported in the recent past. QCM relies on a quartz crystal alternating current-induced oscillations with an inverse relationship between the oscillation frequency and interface phenomena such as mass loading on the surface or changes of the viscosity or density of the media surrounding the sensor.…”

Development of a Soluble KIT (sKIT) Electrochemical Aptasensor For Cancer Theranostics

“…The results of the CM (background subtracted) for HMC-1.2, GIST-T1, and MIA-PaCa2 cells were 6.36 ± 0.28, 3.28 ± 0.55, and 0.03 ± 0.02 ng/mL, respectively. The sKIT levels detected using the aptasensor were higher than that of the ELISA possibly due to the higher affinity reagent and higher sensitivity of the electrochemical sensing approaches (Piro et al, 2016;Wang et al, 2017). To investigate the recovery of the KIT aptasensor, known concentrations of KIT (100 pg/mL, 1 ng/mL, and 10 ng/mL) were spiked in 10× diluted human serum.…”