Impedance spectroscopy for the detection of monosaccharides using functionalized carbon screen-printed electrodes on paper
Daikuzono, Cristiane and Florea, Larisa and Delaney, Colm and Tesfay, Henok and Morrin, Aoife and Diamond, Dermot and Novais de Oliveira Jr., Osvaldo (2016) Impedance spectroscopy for the detection of monosaccharides using functionalized carbon screen-printed electrodes on paper. In: E-MRS 2016 Fall Meeting, 19 to 22 Sept 2016., Warsaw, Poland.
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Here we report a novel sensor, which may have great potentials for the fabrication of low-cost, wearable devices for the detection of monosaccharides (e.g. glucose, fructose) using electrical impedance spectroscopy. The sensor is composed of functionalised carbon interdigitated electrodes (IE) printed on paper. The IE are 10 mm x 15 mm and have 10 digits of 1 mm in width and 7 mm long, and were printed on paper using screen-printing technique. After printing, the electrode surface was modified with a thin hydrogel layer made of a copolymer of acrylamide and 3-(Acrylamido)phenylboronic acid (PBA) in a ratio of 5:1. PBAs are well known for their strong, reversible interactions with diol-containing compounds like sugars (e.g. glucose and fructose)3 making them compounds of choice for the development of a wide range of sensors and biosensors1-3. In this context, we investigated the capacitance and impedance variations with different concentration of glucose and fructose (5-50 mM) present in the phosphate buffer aqueous solution. The electrical measurements were made using Solartron 1260. 20 mV was applied and the impedance was analyzed in a frequency range of 0.1 – 10 MHz. Impedance results show a decrease of impedance values with increasing sugar concentration due to less resistivity to electrical current. The results indicated that the 20 mol % PBA hydrogel swells more when in contact with fructose solution than glucose when the same concentrations of the sugar were employed. This could potentially be used to differentiate between the different sugars present in solution. Future work will focus on the incorporation of these modified carbon printed electrodes in to wearable skin patch type platforms for non-invasive sugar monitoring in sweat.
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