Phospho-Tau 181 quantification method for Alzheimer's disease based on an array 2D biosensor combined with surface plasmon resonance imaging

Abstract

Alzheimer's disease is among the neurodegenerative diseases for which there is a lack of rapid, effective, and non-invasive diagnostic methods. The development of a phospho-Tau 181 assay biosensor is therefore a response to the need for methods to diagnose AD. The present work was aimed at developing a fast, selective, and repeatable method for the quantitative determination of phospho-Tau 181, which could be used even during routine blood tests. Our method is a form of what is called liquid biopsy. The developed method underwent validation, as a result of which its analytical parameters were determined.An LOQ of 3.35 pg mL−1 was obtained, confirming the possibility of trace analysis of phospho-Tau 181 in human plasma. Relative percentage error values below 15 % and CVs in the range 1.47–7.09 % attest to the high accuracy and precision of the presented method. Also, the sample matrix was not found to significantly affect the results obtained for phospho-Tau 181 concentrations. The new SPRi biosensor provides reproducible measurements of the analyte under study (CV = 3.18–4.26 %). Although the method requires absolute adherence to the recommendations of the analytical procedure protocol, it achieves high selectivity and provides 90 % certainty of the correctness of the diagnosis based on measurements of phospho-Tau 181 concentration.