Liquid exfoliation of 2D MoS 2 nanosheets and their utilization as a label-free electrochemical immunoassay for subclinical ketosis

• Published in: Nanoscale Vol. 9; no. 30; pp. 10886 - 10896
• Main Authors: Tuteja, Satish K, Duffield, Todd, Neethirajan, Suresh
• Format: Journal Article
• Language: English
• Published: England 03.08.2017
• Subjects: 3-Hydroxybutyric Acid - analysis; Animals; Biomarkers - analysis; Biosensing Techniques; Electrochemical Techniques; Electrodes; Gold; Humans; Immunoassay; Ketosis - diagnosis; Limit of Detection; Nanostructures
• ISSN: 2040-3364; 2040-3372
• DOI: 10.1039/C7NR04307D

We report the step-by-step fabrication of a 2D MoS nanostructure-based disposable electrochemical immunosensor to detect β-hydroxybutyrate (βHBA), a novel subclinical ketosis biomarker. The MoS nanosheets were exfoliated in the liquid phase by ultrasonication, and then followed by deposition on gold colloid modified screen-printed electrodes (Au-SPE). The MoS -modified electrodes were thoroughly characterized by physical, electrochemical as well as spectroscopic techniques, and the obtained results indicate the successful and irreversible electrodeposition of MoS nanosheets. These MoS -modified disposable electrodes were subsequently bioconjugated with anti-βHBA antibodies and then employed for the label-free immunosensing of the βHBA biomarker to detect subclinical ketosis. A simple electrochemical Differential Pulse Voltammetry (DPV) technique based immunodetection was realized for the sensing of varying concentrations of βHBA antigen. The bioassay demonstrated remarkable sensitivity and specificity having a dynamic linear response range of 0.7 mM to 10 mM for βHBA in standard antigen solutions, spiked serum, blood, milk and clinical samples, with linear results being obtained with R ∼ 0.9923. The sensor electrodes were also studied with other relative interferents to investigate cross reactivity and non-specificity. These electrodes showed a linear, specific, reproducible and stable response towards the βHBA antigen over a wide range of concentrations.