Covalent immobilisation of a nanoporous platinum film onto a gold screen-printed electrode for highly stable and selective non-enzymatic glucose sensing

Abstract

Progress in the development of commercially available non-enzymatic glucose sensors continues to be problematic due to issues regarding selectivity, reproducibility and stability. Overcoming these issues is a research challenge of significant importance. This study reports a novel fabrication process using a double-layer self-assembly of (3 mercaptopropyl)trimethoxysilane (MPTS) on a gold substrate and co-deposition of a platinum–copper alloy. The subsequent electrochemical dealloying of the less noble copper resulted in a nanoporous platinum structure on the uppermost exposed thiol groups. Amperometric responses at 0.4 V vs. Ag/AgCl found the modification to be highly selective towards glucose in the presence of known interferants. The sensor propagated a rapid response time <5 s and exhibited a wide linear range from 1 mM to 18 mM. Additionally, extremely robust stability was attributed to enhanced attachment due to the strong chemisorption between the gold substrate and the exposed thiol of MPTS. Incorporation of metallic nanomaterials using the self-assembly approach was demonstrated to provide a more reproducible and controlled molecular architecture for sensor fabrication. The successful application of the sensor in real blood serum samples displayed a strong correlation with clinically obtained glucose levels.