1. s.sharma@imperial.ac.uk / t.cass@imperial.ac.uk
CHEMICAL CROSS TALK STUDIES ON A MICROPROBE ARRAY BASED CONTINUOUS GLUCOSE MONITORING SENSOR
Sanjiv Sharmaa, Ahmed El-Laboudib, Nick Oliver, Desmond Johnstonb, & Tony Cassa
a Department of Chemistry & Institute of Biomedical Engineering bDivision of Diabetes, Endocrinology & Metabolism, Imperial College London, UK /
Introduction: Despite nearly two decades of technology development in the area of continuous glucose monitoring, the uptake of devices by people with type 1 diabetes remains less than 10%. This can be attributed to multiple factors including reduced accuracy (especially in hypoglycaemia), false alarms, and high costs of manufacture. Various approaches have been pursued to improve the accuracy of continuous glucose monitoring devices, including improvement of the sensor design.
We have developed a minimally invasive electrochemical biosensor for painless, continuous monitoring of dermal interstitial fluid glucose. The device consists of monolithically integrated multiple arrays of microprobes distributed into three working and one reference electrodes. The working electrodes are functionalized with glucose oxidase enzyme entrapped in electropolymerised polyphenols.
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Aim: Evaluation of the sensor design by measuring chemical cross talk between the microprobe array electrodes.
Method: One platinum metalized microprobe array electrode was functionalized with glucose oxidase whilst the other two microprobe array electrodes were left unfunctionalised. Dosimetric response curves were obtained by measuring the current at the three electrodes for 60 seconds at varying glucose concentrations.
Results: Only the microprobe array functionalized with the enzyme showed a response to glucose whilst the other two, non-functionalized microprobe array electrodes gave only background currents.
Figure 1 Dose-response curves obtained after functionalization of a single working electrode (WE1 - black squares) with glucose oxidase. WE2 (blue triangles) and WE3 (red squares) are blank electrodes. (KM = 12.25mM, Imax = 15µA) Inset: Showing the device design of the microprobe array electrode sensor.
Conclusion: The use of techniques such as chronoamperometry helps in measuring any cross talk due to diffusion of hydrogen peroxide from one microprobe array electrode to another. The dosimetric response curve clearly indicates there is no cross talk between the individual electrode arrays thus confirming the suitability of the design in voting electronics and multiplexed measurements.
Copyright © S.Sharma et.al. Imperial College London