Determination of glucose in human serum based on an onion primary cuticula biosensor immobilized glucose oxidase

A glucose biosensor based on onion primary cuticula immobilized glucose oxidase has been developed. The glucose concentration was quantified by the decrease of dissolved oxygen. The effects of enzyme loading, pH, temperature, buffer concentration and interference have been studied in detail. The biosensor showed a wide linear relationship with a concentration range of 20 μM-1.1 mM, a fast response time (70 s), good repeatability (2.8%, n = 10) and satisfactory reproducibility (0.91%, n = 3). The biosensor retained 90% of its initial response after 3 months at 25 °C. The apparent Michaelis-Menten constant K _m was estimated to be 0.042 mM, which revealed higher biological affinity to glucose. The proposed biosensor method has been successfully applied to the determination of glucose concentration in human blood serum and obtained results were agreement with the colorimetric assay kit. The recoveries of proposed method are 95.2-106.3%.