Gold nanoparticle-enhanced flexible electrochemical glucose biosensors

Close monitoring of rapidly changing physiological parameters is an integral part of managing critically ill patients in an intensive care unit (ICU). However, frequent blood draws and laboratory testing introduce delays, discontinuity, and wastage of blood, contributing to poor patient outcomes. Continuous monitoring of critical analytes such as pH, blood gases, glucose, lactate, etc., can provide early detection of complications and enable improved quality of patient care.¹ Although enzymatic sensors based on glucose oxidase offer good specificity, they are susceptible to pH and temperature alterations, loss of enzyme activity over time, denaturation of enzymes, etc.² Therefore, the use of spherical gold nanoparticles (AuNPs) is considered for the enhancement of sensitivity of such glucose sensors. The AuNPs can provide catalytic activity towards glucose or modify standard enzymatic systems by improving the efficiency of electron transfer between the enzymes and the electrodes. We present flexible sensors comprising gold electrodes on polyimide-based substrates fabricated using lithographic patterning and magnetron sputtering techniques. These sensors can be applied in wearable devices or implantable sensing systems to enable continuous monitoring. In our approach, we modify gold electrode surfaces to detect glucose levels by introducing AuNPs at different stages of functionalization to support the charge transfer in enzyme-based measurements or to exploit the modulation of AuNP catalytic activity for sensing. AuNPs with dimensions between 15 and 50 nm were incorporated for signal enhancement. The developed sensors were characterized extensively for sensitivity, reliability, and reproducibility. Our preliminary findings suggest improved stability of electrochemical signals and excellent dynamic range of glucose sensing when AuNPs are introduced. AuNP-enhanced flexible electrochemical biosensors show great promise for use in clinical monitoring settings and integration of these sensors into complete medical devices is part of our ongoing research.

1. Ho, K.K.Y.; Peng, Y.-W.; Ye, M.; Tchouta, L.; Schneider, B.; Hayes, M.; Toomasian, J.; Cornell, M.; Rojas-Pena, A.; Charpie, J.; Chen, H. Evaluation of an Anti-Thrombotic Continuous Lactate and Blood Pressure Monitoring Catheter in an In Vivo Piglet Model undergoing Open-Heart Surgery with Cardiopulmonary Bypass. Chemosensors 2020, 8, 56. https://doi.org/10.3390/chemosensors8030056.
2. Mohammadpour-Haratbar, A.; Mohammadpour-Haratbar, S.; Zare, Y.; Rhee, K.Y.; Park, S.-J. A Review on Non-Enzymatic Electrochemical Biosensors of Glucose Using Carbon Nanofiber Nanocomposites. Biosensors 2022, 12, 1004. https://doi.org/10.3390/bios12111004.