Towards point-of-care diagnosis of Alzheimer’s disease: Multi-analyte based portable chemiresistive platform for simultaneous detection of β-amyloid (1–40) and (1–42) in plasma

Label-free simultaneous detection of Alzheimer’s disease (AD) specific biomarkers Aβ40 and Aβ42 peptides on a single platform using polypyrrole nanoparticle-based chemiresistive biosensors is reported here. The proposed interdigitated-microelectrode based inexpensive multisensor-platform can concurrently detect Aβ40 and Aβ42 in spiked-plasma in the range of 10 -14 – 10 -6 g/mL (with LoDs being 5.71 and 9.09 fg/mL, respectively), enabling the estimation of diagnostically significant Aβ42/Aβ40 ratio. A detailed study has been undertaken here to record the individual sensor responses against spiked-plasma samples with varying amounts and proportions of the two target peptides, towards enabling disease-progression monitoring using the Aβ-ratio. As compared to the existing cost-ineffective brain-imaging techniques such as PET and MRI, and the high-risk CSF based invasive AD biomarkers detecting procedures, the proposed approach offers a viable alternative for affordable point-of-care AD diagnostics, with possible usage in performance evaluation of therapeutic drugs. Towards point-of-care applications, the portable readout used in this work was conjugated with an android-based mobile app for data-acquisition and analysis. • Portable chemiresistive sensing platform for simultaneous detection of Aβ42&Aβ40 peptides in wide range 10 fg/mL-1 µg/mL. • Aβ42&Aβ40 analytes detection in real-time plasma samples. • Generated a correlation between Aβ ratio (Aβ42/ Aβ40) and disease progression. • Detection of Aβ peptides in presence of interfering compounds through the effective minimization of matrix effect. • Feasability of extension of proposed sening platform for simultaneous detection of multi-analytes (more than two).