Fluorescence sensing of glucose

Leah Tolosa, Ignacy Gryczynski, Lisa Randers-Eichhorn, Jonathan Dattelbaum, Govind Rao, Joseph R. Lakowicz

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

2 Scopus citations


We devised an optical assay for glucose based on the genetically-engineered glucose/galactose binding protein (GGBP) from E. coli and phase-modulation fluorometry. A single cysteine mutation was introduced at position 26 of GGBP. When labeled with the sulfhydryl-reactive probe I-ANS, GGBP showed a more than 50% decrease in fluorescence intensity with increasing glucose concentration (Kd approx. 1 μM). This is consistent with the glucose-bound structure of GGBP where residue 26 becomes more exposed to the aqueous media. Since minimal lifetime changes were observed with glucose binding, a modulation sensor was devised wherein a long lifetime ruthenium metal-ligand complex (Ru) was painted on the surface of the cuvette containing ANS26-GGBP. Glucose binding resulted in changes in the relative intensities of ANS26-GGBP and Ru which were observed as dramatic changes in the modulation at a low frequency of 2.1 MHz. The modulation measured at 2.1 MHz accurately determines the glucose concentration to ± 0.2 μM.

Original languageEnglish
Title of host publicationProceedings of SPIE - The International Society for Optical Engineering
PublisherSociety of Photo-Optical Instrumentation Engineers
Number of pages6
ISBN (Print)0819430722
StatePublished - 1 Jan 1999
EventProceedings of the 1999 Advances in Fluorescence Sensing Technology - San Jose, CA, USA
Duration: 24 Jan 199927 Jan 1999

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
ISSN (Print)0277-786X


OtherProceedings of the 1999 Advances in Fluorescence Sensing Technology
CitySan Jose, CA, USA


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