A glucose sensor protein for continuous glucose monitoring

Abstract

In vivo continuous glucose monitoring has posed a significant challenge to glucose sensor development due to the lack of reliable techniques that are non-or at least minimally-invasive. In this proof-of-concept study, we demonstrated the development of a new glucose sensor protein, AcGFP1-GBPcys-mCherry, and an optical sensor assembly, capable of generating quantifiable FRET (fluorescence resonance energy transfer) signals for glucose monitoring. Our experimental data showed that the engineered glucose sensor protein can generate measureable FRET signals in response to glucose concentrations varying from 25 to 800 μM. The sensor developed based on this protein had a shelf life of up to 3 weeks. The sensor response was devoid of interference from compounds like galactose, fructose, lactose, mannose, and mannitol when tested at physiologically significant concentrations of these compounds. This new glucose sensor protein can potentially be used to develop implantable glucose sensors for continuous glucose monitoring.

An In Vivo Spectral Multiplexing Approach for the Cooperative Imaging of Different Disease-Related Biomarkers with Near-Infrared Fluorescent Förster Resonance Energy Transfer Probes

“…This is by far a simpler strategy than using systems in which chromophore-modified (fused) proteins are to be incorporated into cells in order to detect specific molecule interactions (7)(8)(9)30,31). Even though this in vivo approach represents a proof of concept, labeling of macrophages via FRET is expected to work also in other disease models related to spontaneous inflammatory processes, such as rheumatoid arthritis.…”

“…FRET is a phenomenon that takes place when 2 different chromophores (donor and acceptor) with overlapping emission/absorption spectra undergo long-range dipole-dipole coupling (3,4). Several interesting approaches have been reported from microscopic analysis in vitro (5)(6)(7)(8) and ultimately also in vivo (9). In the latter case, mutants of green fluorescent protein (10,11) with varying spectral properties have been used together with recombinant techniques to introduce those fused proteins containing the respective FRET donor and acceptor chromophores into cell systems.…”

Reagentless fluorescent biosensors based on proteins for continuous monitoring systems

“…In an attempt to combine the best of both systems, an interesting approach consists in immobilizing the GBP into dialysis tubing and placing this in a luminometer flow-cell; the pore diameter of the tube enables glucose perfusion without protein leaching [20]. This system has been recently tested as a sensor for continuous monitoring [32,33]. The reporting was FRET using two GFP mutants and the K D of the mutant GBP was tuned to glucose blood levels; however, all assays were performed using glucose solutions.…”

Non-enzymatic assay for glucose by using immobilized whole-cells of E. coli containing glucose binding protein fused to fluorescent proteins

“…The search for the ideal glucose sensor has been a long-time goal of many researchers and as a result, many glucose sensors have been developed in the last few decades [3]. Although many glucose sensing systems have found in vivo applications, the need for a reliable, specific, sensitive and stable glucose sensor is highly required [4]. There are many parameters that affect the development of an optimized glucose sensor such as selectivity, linear range, biocompatibility, response time, reproducibility and reversibility of signal [5].…”