A Thermophilic Apoglucose Dehydrogenase as Nonconsuming Glucose Sensor

Journal of Fluorescence

Geddes

2003

Self Cite

107

We have developed a range of glucose sensing contact lenses, using a daily, disposable contact lens embedded with newly developed boronic acid containing fluorophores. Our findings show that our approach may be suitable for the continuous monitoring of tear glucose levels in the range 50-1000 µM, which typically track blood glucose levels, which are ≈5-10 fold higher. Our non-invasive approach may well offer an alternative solution to current invasive glucose monitoring techniques for diabetes, such as "finger pricking."

Section: Introductionmentioning

confidence: 99%

A Glucose Sensing Contact Lens: A Non-Invasive Technique for Continuous Physiological Glucose Monitoring

Badugu

Journal of Fluorescence

Geddes

2003

Self Cite

107

“…Noninvasive measurements of blood glucose have been a long-standing research goal. To date, a wide variety of methods have been described in the literature, including near-infrared spectroscopy (3)(4)(5), optical rotation (6, 7), amperometric (8,9), colorimetric (10,11), and fluorescence detection (12)(13)(14)(15)(16). Despite some promising results, these methods show limitations.…”

mentioning

confidence: 99%

“…Competitive glucose assays using fluorescence resonance energy transfer between concanavalin A and dextran have been developed (13)(14)(15)18). There also have been efforts to use the fluorescence change of labeled apoglucose oxidase (16). Proteins and enzymes have the advantage of showing affinity constants comparable with the blood glucose level and high selectivity.…”

mentioning

confidence: 99%

Evaluation of Two Synthetic Glucose Probes for Fluorescence-Lifetime-Based Sensing

DiCesare

Analytical Biochemistry

2001

Self Cite

We evaluated two anthracene derivatives with covalently attached boronic acid groups for fluorescence-lifetime-based sensing of glucose. These anthracene derivatives also contained alkyl amino groups, which quenched the anthracene emission by photo-induced electron transfer. Both anthracene derivatives displayed increased intensities and lifetime in the presence of glucose, as seen from the frequency-domain measurements. A fluorescence lifetime change from 9.8 to 12.4 and 5.7 to 11.8 ns is observed, after the addition of glucose, for the anthracene substituted with one and two boronic acid groups, respectively. This results in a change in the phase angle up to 15 degrees and 30 degrees and in the modulation up to 12 and 25% at 30 MHz for these compounds, respectively. Titration curves in the presence of BSA and micelles are also presented to show the potential interferences from biomolecules. Dissociation constants were evaluated for both compounds, and association with glucose was found to be reversible. Importantly, the apparent glucose binding constants are about 5- to 10-fold smaller with phase, modulation, or mean lifetime than with intensities measurements, shifting the glucose-sensitive range to physiological values. Combining these results and the use of a simple UV-LED as excitation source, the results show an interesting potential of these two compounds in the development of lifetime base devices using synthetic probes for glucose.

“…To this end, many technologies have been developed over the past 20 years in an attempt to provide a technology which promises both non-invasive and continuous physiological glucose monitoring. These include near infrared spectroscopy [3,4], optical rotation [5,6], colorimetric [7,8] and fluorescence detection [9][10][11][12][13], to name but just a very few. Recently we have seen the launch of the new GlucoWatch, which approved by the FDA in 2001, is the first step towards both the continuous and non-invasive monitoring of physiological glucose.…”

Section: Introductionmentioning

confidence: 99%

Ophthalmic Glucose Monitoring Using Disposable Contact Lenses—A Review

Badugu

Journal of Fluorescence

Geddes

2004

Self Cite

We have developed a range of disposable and colorless tear glucose sensing contact lenses, using offthe-shelf lenses embedded with new water soluble, highly fluorescent and glucose sensitive boronic acid containing fluorophores. The new lenses are readily able to track tear glucose levels and therefore blood glucose levels, which are ideally suited for potential use by diabetics. The fluorescence responses from the lenses can be monitored using simple excitation and emission detection devices. The novelty of our approach is two fold. Firstly, the notion of sensing extremely low glucose concentrations in tears, which track blood levels, by our contact lens approach, and secondly, the unique compatibility of our new glucose signaling probes with the internal mildly acidic contact lens environment. The new lenses are therefore ideal for the non-invasive and continuous monitoring of tear glucose, with about 15-min response time, and a measured shelf life in excess of 3 months. In this review article, we show that fluorescence based signaling using plastic disposable lenses, which have already been industrially optimized with regard to vision correction and oxygen/analyte permeability etc, may a notable alternative to invasive and random finger pricking, the most widely used glucose monitoring technology by diabetics.