Near‐Infrared Resonance Energy Transfer Glucose Biosensors in Hybrid Microcapsule Carriers

Fluorescence-based sensing systems offer potential for noninvasive monitoringwith implantable devices, but require carrier technologies that provide suitableimmobilization, accessibility, and biocompatibility. Recent developments towards this goalinclude a competitive binding assay for glucose that has been encapsulated in semipermeablemicrocapsule carriers. This paper describes an extension of this work to increase the applicabilityto in vivo monitoring, wherein two significant developments are described: (1) a near-infraredresonance energy transfer system for transducing glucose concentration, and (2) novel hybridorganic-inorganic crosslinked microcapsules as carriers. The quenching-based assay isa competitive binding (CB) system based on apo-glucose oxidase (AG) as the receptor anddextran as the competitive ligand. The encapsulated quencher-labeled dextran and near infrareddonor-labeled glucose receptor showed a stable and reversible response with tunable sensitivityof 1–5%/mM over the physiological range, making these transducers attractive forcontinuous monitoring for biomedical applications