3D-Printed Electrochemical Platform for Detection of Diabetes Biomarkers: Drop-Based and Time-Based Readout for Clinical Diagnosis

Multiplex detection of biomarkers in clinical matrices on a single sensor platform is the need for a detailed disease diagnosis and patient prognosis. Herein, we demonstrate immunoassay/enzyme detection assay formats on a 3D-printed device for measuring insulin, C peptide, and glucose in two-fold diluted human serum electrochemically. The sensor platform comprised of a graphene–gold (Gr–Au) framework to immobilize insulin and C peptide specific antibodies and glucose oxidase to detect clinically relevant levels of diabetes biomarkers with good sensitivity, specificity, and reproducibility. The fabrication of the 3D-printed sensor platform is characterized by field emission scanning electron microscopy (FESEM) and electron impedance spectroscopy (EIS). The current signals for detection of free serum insulin, C peptide were monitored by oxidation of ferro/ferricyanide redox probe, while glucose was detected directly using square wave voltammetry (drop-based) and amperometry (real-time). The designed electrochemical platform offered a limit of detection (LOD) 4 pM insulin, 0.02 nM C peptide, and 0.05 mM glucose. The Gr–Au framework was ~ 2.5× more sensitive in detecting diabetes biomarkers in human serum when compared to pristine Gr framework. Additionally, the sensor does not show any cross-reactivity to non-specific biomarkers in human serum. © The Author(s), under exclusive licence to Springer Science+Business Media, LLC 2022.