Received on July 14, 2004
Accepted on September 1, 2004

Automation and Analytical Techniques

Photonic Crystal Glucose-Sensing Material for Noninvasive Monitoring of Glucose in Tear Fluid

¹ Department of Chemistry, Chevron Science Center, and Glucose Sensing Technologies LLC, Pittsburgh, PA
² Department of Chemistry, Chevron Science Center
³ Department of Pediatrics, University of Pittsburgh Medical School, University of Pittsburgh, Pittsburgh, PA

Background: We recently developed photonic crystal glucose-sensing material (Alexeev et al., Anal Chem 2003;75:2316-23), which consists of a crystalline colloidal array embedded within a polymer network of a polyacrylamide-poly(ethylene glycol) hydrogel with pendent phenylboronic acid groups. The aim of the present work was to improve this approach for application to noninvasive or minimally invasive monitoring of glucose.

Methods: We used new boronic acid derivatives such as 4-amino-3-fluorophenylboronic acid and 4-carboxy-3-fluorophenylboronic acid as the molecular recognition elements to achieve sensing at physiologic pH values.

Results: The improved photonic glucose-sensing material sensed glucose in the range of the 100 µmol/L concentrations found in tear fluid. The detection limits were 1 µmol/L in synthetic tear fluid. The visually evident diffraction color shifted across the entire visible spectral region from red to blue over the physiologically relevant tear-fluid glucose concentrations. This sensing material is selective for glucose over galactose, mannose, and fructose.

Conclusions: These new glucose sensors have properties appropriate for use in such glucose-sensing applications as ocular inserts or diagnostic contact lenses for patients with diabetes mellitus.