A fluorescence-based glucose biosensor using concanavalin A and dextran encapsulated in a poly(ethylene glycol) hydrogel.
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 alpha-acryloyl, omega-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 micrograms/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 approximately 10 min for a glucose concentration step change from 0 to 200 mg/dL.
Russell
R J
RJ
Department of Chemical Engineering, Texas A&M University, College Station 77843-3122, USA.
Pishko
M V
MV
Gefrides
C C
CC
McShane
M J
MJ
Coté
G L
GL
D015374:Biosensing Techniques; D003208:Concanavalin A / Q000737:chemistry / Q000378:metabolism*; D003911:Dextrans / Q000737:chemistry* / Q000378:metabolism; D016650:Fluorescein-5-isothiocyanate / Q000031:analogs & derivatives / Q000737:chemistry; D005453:Fluorescence; D005456:Fluorescent Dyes / Q000737:chemistry; D005947:Glucose / Q000032:analysis* / Q000378:metabolism; D020100:Hydrogels / Q000737:chemistry*; D008422:Materials Testing; D011092:Polyethylene Glycols / Q000737:chemistry; D012235:Rhodamines / Q000737:chemistry; D013997:Time Factors
D003911:Dextrans; D005456:Fluorescent Dyes; D020100:Hydrogels; D012235:Rhodamines; C015219:fluorescein isothiocyanate dextran; D003208:Concanavalin A; D011092:Polyethylene Glycols; C009434:tetramethylrhodamine isothiocyanate; D016650:Fluorescein-5-isothiocyanate; D005947:Glucose