A novel nanomachined flow channel glucose sensor based on an alumina membrane

In the present study, the construction of a nanomachined flow channel sensor based on a nanoporous alumina membrane (NAM) together with information on its kinetic biosensing for real-time electrochemical detection of glucose are described. Firstly, the enzyme glucose oxidase was covalently immobilized on nanochannels of NAM as active biosensing elements, and a thin film of Pt was sputtered at the end of the nanochannels as an electrochemical detector. When the glucose solutions flowed through the nanochannels at a certain flux, the hydrogen peroxide (H2O2) produced as a result of enzymatic conversion was detected by an amperometric method at the end face of the Pt film sputtered membrane. The results showed that the H(2)O(2)produced in the nanochannels was completely collected at the Pt film electrode due to the unique nanoscale channels. Thus, the detection sensitivity of glucose was significantly improved to as high as 86.62 mu A mM(-1) cm(-2) at a flow rate of 20 mu L min(-1). It was also found that the amperometric signal of glucose was directly related to the imposed flow rate. The increased sensitivity of the sensor at a faster flow rate was at the cost of a reduction of the dynamic range of glucose. The present nanochannel sensor exhibited excellent stability and reproducibility even with a usage time of ten days. The proposed sensor was used to detect glucose in wine samples, and the results obtained were in good agreement with the values obtained by a spectrophotometric enzyme method.