Transmembrane Protein-Based Electrochemical Biosensor for Adiponectin Hormone Quantification

Decreased adiponectin hormone secretion occurs 10-20 years before chronic hyperglycemia, and is a great indicator of further development of type 2 diabetes. Here, we developed an electrochemical biosensor for adiponectin quantification based on specific transmembrane receptors (AdipoR1 and AdipoR2). Under optimized conditions, cyclic-voltammetry-based adiponectin biosensors displayed linearity (R-2 = 0.992) in a wide range of concentrations (0.025-0.75 mu mol L-1), including typical human serum levels, with a detection limit of 7.0 nmol L-1 and reproducibility of 1.7%, n = 3. Electrochemical impedance spectroscopy results showed a similar behavior, with a linear increase in charge-transfer resistance (R-2 = 0.971) from 0.025 to 1.00 mu mol L-1, a detection limit of 7.0 nmol L-1, and reproducibility of 5.6 %, n = 3. Furthermore, the analytical results obtained by using the biosensor in human serum samples were in agreement with those obtained by using the enzyme-linked immunosorbent assay (ELISA) at a 95% confidence level. It is expected the proposed device increases the number of predictive type2 diabetes diagnostics, promoting early treatment and patient awareness about the precautions to be taken.