Studies on Carbon Mediated Paste Screen Printed Sensors for Blood Glucose Sensing Application

Abstract

Ready-to-use screen printed glucose sensors are fabricated using Prussian Blue (PB) and Cobalt Phthalocyanine (CoPC) mediated carbon paste as working electrodes. The reference and counter electrodes are screen printed using silver/silver chloride and graphitic carbon paste respectively. The screen printed reference electrode (internal reference electrode (IRE)) is found to be stable for more than 60 minute when examined with standard calomel electrode. Optimal operating voltage for PB and CoPC screen printed sensors as determined by hydrodynamic voltammetric technique. The sensing characteristics of the fabricated sensors towards H2O2 are conducted and response found to be good. Glucose oxidase is immobilized on the working electrodes by cross-linking method. PB mediated glucose sensor exhibits a sensitivity of 5.60 mAcm-2/mM for the range 10 to 1000 μM. Sensitivity CoPC mediated glucose sensor are found to be 5.224 µAcm-2/mM. The amperometeric response is linear for the range, 100 to 1500 μM. Interference studies on the fabricated glucose sensors are conducted with species like uric acid and ascorbic acid. PB mediated sensors showed a completely interference-free behavior; while CoPC mediated sensors are influenced by uric acid and ascorbic acid due to higher operating voltage. The sensing characteristics of PB mediated glucose sensors are also studied in diluted human serum samples and the results are compared with the values obtained by standard clinical method. The co-efficient of variation found to be less than 5 %.