Received on May 7, 2007
Accepted on August 2, 2007

Automation and Analytical Techniques

Continuous Blood Glucose Monitoring with a Thin-Film Optical Sensor

¹ Smart Holograms Ltd., Cambridge, United Kingdom

^* To whom correspondence should be addressed. E-mail: john.pritchard{at}smartholograms.com.

Background: We recently described a holographic optical sensor with improved selectivity for glucose over fructose that was based on a thin-film polymer hydrogel containing phenylboronic acid receptors. The aim of the present work was to measure glucose in human blood plasma as opposed to simple buffers and track changes in concentration at a rate mimicking glucose changes in vivo.

Methods: We used holographic sensors containing acrylamide, N,N'-methylenebisacrylamide, 3-acrylamidophenylboronic acid, and (3-acrylamidopropyl)trimethylammonium chloride to measure 7 human blood plasma samples at different glucose concentrations (3–33 mmol/L) in static mode. Separately, using a flow cell, the glucose concentration was varied at approximately 0.17–0.28 mmol/L/min [mmol^-1·L^-1·min^-1], and the sensor's ability to continuously monitor glucose was investigated over an extended period.

Results: We subjected the results of the ex vivo static measurements to error grid analysis. Of 46 measurements, 42 (91.3%) fell in zone A of a Clarke error grid, and the remainder (8.7%) fell in zone B. The ex vivo flow experiments showed that the sensor is able to accurately track changes in concentration occurring in real time without lag or evidence of hysteresis.

Conclusions: We demonstrate the ability of a phenylboronic acid–based sensor to measure glucose in human blood plasma for the 1st time in vitro. Holographic glucose sensors can be used without recourse to recalibration. Their robust nature, coupled with their format flexibility, makes them an attractive alternative to conventional electrochemical enzyme-based methods of glucose monitoring for people with diabetes.