A Disposable Biosensor For Noninvasive Diabetic Diagnosis Rest On The Au/TiO₂ Nano-composite Intensified Electrochemiluminescence

Diabetes mellitus, commonly referred to as diabetes, is a group of metabolic diseases in which there are high blood sugar levels over a prolonged period.. With the improvement of people’s living standard, diabetes has become the third most dangerous disease, second only to cardiovascular disease and cancer. so it’s therapeutic, diagnostic and control has become a major issue facing with the medical profession.Currently, the vast majority of the glucose sensor is still stuck in detecting blood glucose by taking blood samples, which not only increasing the discomfort of diabetic patients, but also accumulating risk of infection for patients. Thus, non-invasive blood glucose detection method has important practical implications for the treatment of diabetes.Electrochemiluminescence（ECL） has attracted more attention recently due to its promising advantages such as high sensitivity, low detection limit and wide linear range.In this work, using luminol as a light emitting material, modified the Au/TiO₂nano-composite on a disposable glass sheet coated with indium tin oxide（ITO） and cross-linked with bovine serum albumin（BSA） by glutaraldehyde（GD） after calcined,the immobilized glucose oxidase（GOD） on electrode surface as the sensing matrix catalyzed the oxidation of glucose to produce H2O2, which resulted in an enhanced ECL emission. The preparation process of the glucose biosensor was characterized by scanning electron microscopy（SEM）, transmission electron microscope（TEM） and electrochemical impedance spectroscopy（EIS）. Under the optimized conditions, this biosensor showed rather good stability, selectivity, sensitivity and simplicity. It has a wide linear range on detection of glucose from 7 μM to 100 μM with a detection limit of0.22 μM.This sensor has been successfully applied to detect the glucose in diluted human serums and saliva samples, respectively. Therefore, this sensor could be regarded as a simple, practical and disposable device in a noninvasive manner of routine glucose monitoring for those diabetics.