Bioengineering a glucose oxidase nanosensor for near-infrared continuous glucose monitoring

• Main Authors: Boghossian, A.A (Author), Cattaneo, S. (Author), Glieder, A. (Author), Schuergers, N. (Author), Wang, H. (Author), Weninger, A. (Author), Zubkovs, V. (Author)
• Format: Article
• Language: English
• Published: Royal Society of Chemistry 2022
• Online Access: View Fulltext in Publisher

 Single-walled carbon nanotubes (SWCNTs) emit photostable near-infrared (NIR) fluorescence that is conducive for optical glucose monitoring. Such SWCNT-based optical sensors often require the immobilization of proteins that can confer glucose selectivity and reactivity. In this work, we immobilize a glucose-reactive enzyme, glucose oxidase (GOx), onto SWCNTs using a N-(1-pyrenyl)maleimide (PM) crosslinker via thiol bioconjugation of engineered cysteine residues. We compare the conjugation of several glucose oxidase variants containing rationally-engineered cysteines and identify a D70C variant that shows effective bioconjugation. The bioconjugation was characterized through both absorption and fluorescence spectroscopy. Furthermore, we demonstrate an application for continuous glucose monitoring in the NIR-II optical region using the bioconjugated reaction solution, which shows a reversible response to physiological concentrations of glucose. Finally, we develop a miniaturized NIR-II reader to be used for cell cultures that require continuous glucose monitoring. © 2022 RSC