title: Nanostructured biosensor for detecting glucose in tear by applying fluorescence resonance energy transfer quenching mechanism.
abstract: In this paper, a nanostructured biosensor is developed to detect glucose in tear by using fluorescence resonance energy transfer (FRET) quenching mechanism. The designed FRET pair, including the donor, CdSe/ZnS quantum dots (QDs), and the acceptor, dextran-binding malachite green (MG-dextran), was conjugated to concanavalin A (Con A), an enzyme with specific affinity to glucose. In the presence of glucose, the quenched emission of QDs through the FRET mechanism is restored by displacing the dextran from Con A. To have a dual-modulation sensor for convenient and accurate detection, the nanostructured FRET sensors were assembled onto a patterned ZnO nanorod array deposited on the synthetic silicone hydrogel. Consequently, the concentration of glucose detected by the patterned sensor can be converted to fluorescence spectra with high signal-to-noise ratio and calibrated image pixel value. The photoluminescence intensity of the patterned FRET sensor increases linearly with increasing concentration of glucose from 0.03mmol/L to 3mmol/L, which covers the range of tear glucose levels for both diabetics and healthy subjects. Meanwhile, the calibrated values of pixel intensities of the fluorescence images captured by a handhold fluorescence microscope increases with increasing glucose. Four male Sprague-Dawley rats with different blood glucose concentrations were utilized to demonstrate the quick response of the patterned FRET sensor to 2µL of tear samples.
authors.affiliation: Department of Chemical & Biochemical Engineering, University of Western Ontario, London, Ontario, Canada N6A 5B9.
authors.forename: Longyi
authors.initials: L
authors.lastname: Chen
authors.affiliation: Department of Medical Biophysics, University of Western Ontario, London, Ontario, Canada N6A 5B9.
authors.forename: Wai Hei
authors.initials: WH
authors.lastname: Tse
authors.affiliation: Department of Chemical & Biochemical Engineering, University of Western Ontario, London, Ontario, Canada N6A 5B9.
authors.forename: Yi
authors.initials: Y
authors.lastname: Chen
authors.affiliation: School of Kinesiology, Faculty of Health Sciences, University of Western Ontario, London, Ontario, Canada N6A 5B9.
authors.forename: Matthew W
authors.initials: MW
authors.lastname: McDonald
authors.affiliation: School of Kinesiology, Faculty of Health Sciences, University of Western Ontario, London, Ontario, Canada N6A 5B9.
authors.forename: James
authors.initials: J
authors.lastname: Melling
authors.affiliation: Department of Chemical & Biochemical Engineering, University of Western Ontario, London, Ontario, Canada N6A 5B9; Department of Medical Biophysics, University of Western Ontario, London, Ontario, Canada N6A 5B9. Electronic address: jzhang@eng.uwo.ca.
authors.forename: Jin
authors.initials: J
authors.lastname: Zhang
mesh_terms: D000818:Animals; D015374:Biosensing Techniques / Q000379:methods*; D001786:Blood Glucose / Q000032:analysis*; D019187:Cadmium Compounds / Q000737:chemistry; D032449:Canavalia / Q000737:chemistry; D004396:Coloring Agents / Q000737:chemistry; D003208:Concanavalin A / Q000737:chemistry; D003911:Dextrans / Q000737:chemistry; D031541:Fluorescence Resonance Energy Transfer / Q000379:methods*; D005947:Glucose / Q000032:analysis*; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate / Q000737:chemistry; D008297:Male; D008958:Models, Molecular; D043942:Nanotubes / Q000737:chemistry / Q000648:ultrastructure; D045663:Quantum Dots / Q000737:chemistry* / Q000648:ultrastructure; D017207:Rats, Sprague-Dawley; D012394:Rosaniline Dyes / Q000737:chemistry; D018036:Selenium Compounds / Q000737:chemistry; D059629:Signal-To-Noise Ratio; D012825:Silicon / Q000737:chemistry; D013440:Sulfides / Q000737:chemistry; D013666:Tears / Q000737:chemistry*; D017967:Zinc Compounds / Q000737:chemistry; D015034:Zinc Oxide / Q000737:chemistry
chemical_list: D001786:Blood Glucose; D019187:Cadmium Compounds; D004396:Coloring Agents; D003911:Dextrans; D012394:Rosaniline Dyes; D018036:Selenium Compounds; D013440:Sulfides; D017967:Zinc Compounds; D003208:Concanavalin A; C005095:malachite green; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate; C058667:cadmium selenide; D005947:Glucose; C031238:zinc sulfide; D015034:Zinc Oxide; D012825:Silicon
keywords: Fluorescence resonance energy transfer (FRET); Non-invasive biosensor; Quantum dots; Silicone hydrogel; Tear glucose