A Fluorescence-Based Glucose Biosensor Using Concanavalin A and Dextran Encapsulated in a Poly(ethylene glycol) Hydrogel

• Published in: Analytical chemistry (Washington) Vol. 71; no. 15; pp. 3126 - 3132
• Main Authors: Russell, Ryan J, Pishko, Michael V, Gefrides, Christopher C, McShane, Michael J, Coté, Gerard L
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 01.08.1999
• Subjects: Biological and medical sciences; Biosensing Techniques; Biosensors; Biotechnology; Chemistry; Concanavalin A - chemistry; Concanavalin A - metabolism; Dextrans - chemistry; Dextrans - metabolism; Fluorescein-5-isothiocyanate - analogs & derivatives; Fluorescein-5-isothiocyanate - chemistry; Fluorescence; Fluorescent Dyes - chemistry; Fundamental and applied biological sciences. Psychology; Glucose; Glucose - analysis; Glucose - metabolism; Hydrogels - chemistry; Materials Testing; Methods. Procedures. Technologies; Polyethylene Glycols - chemistry; Rhodamines - chemistry; Time Factors; Various methods and equipments; Dextran; Encapsulation; Ethylene oxide polymer; Fluorescent labelling; Biosensor; Glucose; Hydrogel; Concanavalin A; Medical application; Quantitative analysis; Biomedical engineering
• ISSN: 0003-2700; 1520-6882
• DOI: 10.1021/ac990060r

A fluorescence biosensor is described that is based on a photopolymerized poly(ethylene glycol) (PEG) hydrogel incorporating fluorescein isothiocyanate dextran (FITC-dextran) and tetramethylrhodamine isothiocyanate concanavalin A (TRITC-Con A) chemically conjugated into the hydrogel network using an α-acryloyl, ω-N-hydroxysuccinimidyl ester of PEG-propionic acid. In the absence of glucose, TRITC-Con A binds with FITC-dextran, and the FITC fluorescence is quenched through fluorescence resonance energy transfer. Competitive glucose binding to TRITC-Con A liberates FITC-dextran, resulting in increased FITC fluorescence proportional to the glucose concentration. In vitro experiments of hydrogel spheres in a solution of 0.1 M phosphate-buffered saline (pH 7.2) and glucose were conducted for multiple TRITC-Con A/FITC-dextran ratios. Hydrogels were characterized on the basis of the percent change in fluorescence intensity when FITC-dextran was liberated by increasing glucose concentrations. The optimum fluorescent change between 0 and 800 mg/dL was obtained with a TRITC-Con A/FITC-dextran mass ratio of 500:5 μg/mL PEG. Fluorescent response was linear up to 600 mg/dL. At higher concentrations, the response saturated due to the displacement of the majority of the FITC-dextran and to concentration quenching by free FITC-dextran. Dynamic fluorescent change upon glucose addition was ∼10 min for a glucose concentration step change from 0 to 200 mg/dL.