Detection of Glycated Albumin Using a Novel Field Effect Aptasensor

In this paper, we propose a new field effect (FE) sensor for fast detection of glycated albumin (GA) based on thiol modified aptamer (TMA). A p-type Si/ (100 nm) SiO
₂
wafer was used, where the SiO
₂
layer acts as the gate insulator. This gate insulator is then decorated with a layer of randomly oriented ZnO nanorods, coated with 40 nm of Au to act as binding sites for the TMA. We have shown that the addition of GA significantly reduces the conductivity of the p-type Si channel, which can be used to determine the GA concentration in the test solution. The ZnO/Au/TMA/GA layer can induce negative charges in the Si channel underneath the gate insulator, which is followed by the depletion of the positively charged carriers of the Si, decreasing the conductivity. Accordingly, the charge carriers in the Si channel show a steady decline with increasing GA concentration. We have shown that this decrease in conductivity can be further tuned by varying the gate voltage. The sensor presented here can be used as a fast and reliable sensor for determination of GA.