Fabrication of a microdialysis-based nonenzymatic microfluidic sensor for regular glucose measurement

Abstract

Microdialysis-based continuous glucose measuring systems are desirable candidates for accurate and biologically safe monitoring of glucose level in diabetic patients. However, it is necessary to improve these systems by utilizing highly reliable non-enzymatic sensors instead of enzymatic ones, while lowering the size and lessening the dialysis fluid consumption. Our purpose is to design an implantable integrated microfluidic device for regular nonenzymatic microdialysis-based glucose measurement. We report a novel nonenzymatic microfluidic glucose sensor based on Pt-Ni nanoparticles - multiwalled carbon nanotubes/screen-printed carbon electrode (Pt-Ni NPs-MWCNTs/SPE). Devised microfluidic sensor consists of a channel of a height as low as 60μm, with the modified screen-printed electrode beneath. Microfluidic tests were performed by pumping the dialysis fluid (pH=7.4) through the sensor at the flow rate of only 1 μL min−1. Fabricated microfluidic sensor exhibited satisfactory repeatability, reproducibility, and showed amperometric bisectional linear current response with sensitivities of 6.67 μA mM-1 cm-2 and 4.57 μA mM-1 cm-2 in two glucose concentration ranges of ⩽8mM and 8–12 mM, respectively. These properties, along with small channel size, low fluid consumption and high resistance to Cl- poisoning make the sensor a highly suitable candidate for our purpose. Finally, in an innovative process, a numerical simulation was utilized, showing that the sensitivity of the fabricated sensor can be theoretically increased 1.864 times the experimentally achieved value.