Impedimetric biosensor based on gold nanostructures and concanavalin A for glycoproteins detection

Glycoproteins play critical roles in biological processes and serve as key biomarkers in diseases such as cancer. They also represent a significant category of biopharmaceuticals, such as monoclonal antibodies and therapeutic enzymes where glycosylation critically impacts their stability, efficacy, and immunogenicity. Consequently, reliable analytical methods are essential for assessing glycoproteins in both clinical diagnostics and biomanufacturing. In this work, it was developed a label-free impedimetric biosensor for glycoprotein detection using Concanavalin A immobilized on a self-assembled monolayer-modified screen-printed gold electrode. The biosensor construction was optimized through gold electrodeposition, mitigating batch-to-batch variability and improving sensor reproducibility, by combining an initial pre-treatment with potassium hydroxide + hydrogen peroxide with the electrodeposition of Au nanostructures. Electrochemical impedance spectroscopy was employed to monitor glycoprotein-lectin interactions, with invertase as a model glycoprotein. The biosensor demonstrated good sensitivity, achieving a detection limit of 0.19 nM for invertase and 0.69 μM for Rituximab (therapeutic mAb). Differences in glycan structure and charge influenced biosensor response. The sensor's applicability in biopharmaceutical analysis was validated through Rituximab detection in a surrogate cell culture supernatant, achieving a recovery of 101 %. These findings underscore the potential of Concanavalin A-based impedimetric biosensors for rapid, cost-effective tool for glycoprotein analysis in biopharmaceutical quality control.