Label-free detection of β-Amyloid (1-42) in Plasma using electrospun SnO2 nanofiber based electro-analytical sensor

Supraja, Patta and Tripathy, Suryasnata and Vanjari, Siva Rama Krishna and Singh, Ranjana and Singh, Vikrant and Singh, Shiv Govind (2021) Label-free detection of β-Amyloid (1-42) in Plasma using electrospun SnO2 nanofiber based electro-analytical sensor. Sensors and Actuators B: Chemical. p. 130522. ISSN 09254005

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Abstract

Uncontrolled fibrous aggregation of proteins in the human brain implicates a range of anomalous biological phenomena, ultimately leading to Alzheimer's Disease (AD). Aggregates of β-Amyloid(1-42) (AB42) have been considered the most viable biomarker for early diagnosis of AD; therefore, it is highly essential to detect AB42 peptides in easily accessible body fluids, preferably at low concentrations. Considering this, we report the design and development of a facile, sensitive, and label-free electrochemical biosensor for AB42 peptide detection, using electrospun SnO2 nanofibers (SNF) as the transducing material. The sensing platform, comprising of AB42-specific capture antibodies covalently immobilized onto SNF nanofiber modified carbon working electrodes, acts as an immunoassay on to which the target analytes bind specifically. In response, the charge transfer resistance at the sensor interface gets modified proportionately and is recorded using electrochemical impedance spectroscopy. Herein, we have tested the efficiency of the said immunoassay against AB42 spiked buffer and plasma samples, in the concentration range 1 fg/mL–1 µg/mL. The proposed platform accounts for a sensitivity (limit of detection (LoD)) of 274.96(kΩ/ng.mL−1)/cm2 (0.146 fg/mL) and 302.05(kΩ/ng.mL−1)/cm2 (0.638 fg/mL) for AB42 spiked buffer and plasma samples, respectively. Furthermore, the proposed SNF-derived electrochemical immunoassay shows appreciable stability (over 126 days), selectivity, repeatability, reproducibility, and interference-resistance.

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