earticle

영어

Here we describe an n-type ion sensitive field effect transistor (n-type ISFET) biosensor, which is designed to directly monitor the surface charge of structurally altered maltose binding protein (MBP) upon stimulation with maltose. To our best knowledge, this study reports the first application of FET biosensor for the monitoring of conformationally changed protein. In this work, silicon dioxide (SiO2) has been used as the a material of the ISFET device, and Pt reference electrode employed for detecting the variations of surface charge in MBP. Histidine-tagged MBP was immobilized onto a NTA-Ni(II)-coated sensing layer (SiO2), subsequently treated with maltose to induce conformational changes in MBP. As a result, a significant decrease in drain current of ISFET device has been clearly observed in response to maltose, but not glucose as a control, indicating that substrate-specific conformational properties of target protein could be successfully monitored using ISFET biosensor. Collectively, our data strongly demonstrated that ISFET biosensor provides a high fidelity system for the detection of maltose-induced structural alterations in MBP by analyzing the changes in drain current based on the charge-dependent capacitance measurement.