title: A fluorescence lifetime-based fibre-optic glucose sensor using glucose/galactose-binding protein.
abstract: Alternative, non-electrochemistry-based technologies for continuous glucose monitoring are needed for eventual use in diabetes mellitus. As part of a programme investigating fluorescent glucose sensors, we have developed fibre-optic biosensors using glucose/galactose binding protein (GBP) labelled with the environmentally sensitive fluorophore, Badan. GBP-Badan was attached via an oligohistidine-tag to the surface of Ni-nitrilotriacetic acid (NTA)-functionalized agarose or polystyrene beads. Fluorescence lifetime increased in response to glucose, observed by fluorescence lifetime imaging microscopy of the GBP-Badan-beads. Either GBP-Badan agarose or polystyrene beads were loaded into a porous chamber at the end of a multimode optical fibre. Fluorescence lifetime responses were recorded using pulsed laser excitation, high speed photodiode detection and time-correlated single-photon counting. The maximal response was at 100 mM glucose with an apparent K(d) of 13 mM (agarose) and 20 mM (polystyrene), and good working-day stability was demonstrated. We conclude that fluorescence lifetime fibre-optic glucose sensors based on GBP-Badan are suitable for development as clinical glucose monitors.
authors.affiliation: Diabetes Research Group, King's College London School of Medicine, Guy's Hospital, London, SE1 1UL, UK.
authors.forename: Tania
authors.initials: T
authors.lastname: Saxl
authors.forename: Faaizah
authors.initials: F
authors.lastname: Khan
authors.forename: Matteo
authors.initials: M
authors.lastname: Ferla
authors.forename: David
authors.initials: D
authors.lastname: Birch
authors.forename: John
authors.initials: J
authors.lastname: Pickup
mesh_terms: D015374:Biosensing Techniques / Q000295:instrumentation / Q000379:methods*; D002135:Calcium-Binding Proteins / Q000737:chemistry* / Q000378:metabolism; D005453:Fluorescence; D005947:Glucose / Q000032:analysis*; D008856:Microscopy, Fluorescence; D008863:Microspheres; D009004:Monosaccharide Transport Proteins / Q000737:chemistry* / Q000378:metabolism; D009571:Nitrilotriacetic Acid / Q000737:chemistry; D055100:Optical Fibers; D033902:Periplasmic Binding Proteins / Q000737:chemistry* / Q000378:metabolism; D011137:Polystyrenes / Q000737:chemistry; D012685:Sepharose / Q000737:chemistry; D013997:Time Factors
chemical_list: D002135:Calcium-Binding Proteins; D009004:Monosaccharide Transport Proteins; D033902:Periplasmic Binding Proteins; D011137:Polystyrenes; C023550:galactose-binding protein; D012685:Sepharose; D005947:Glucose; D009571:Nitrilotriacetic Acid