Silicon-on-insulator FET biosensor for dengue DNA complementation

In this paper, a label-free approach utilizing field-effect transistor (FET) biosensor is presented and demonstrated for deoxyribonucleic acid (DNA) detection related to dengue virus. The biologically active element (in this case for DNA) will have a reaction with a physical transducer (i.e. channel area that connecting the source and drain) and transforms the reaction into a quantifiable signal. This event occurs when an analyte is bound to the recognition element after surface modification, the charge distribution at the surface resulting in current flow across the channel. The field-effect transistor was fabricated using the conventional photolithography approach on thin silicon-on-insulator (SOI) wafer. The source and drain are either doped or undoped (as it initial intrinsic impurity is 1x1015 cm−3). The fabricated device of FET was then observed under scanning electron microscope (SEM), atomic force microscope (AFM), and 3D nano-profilometer to characterize the surface morphology. In addition, the electrical characterization was also performed using Keithley 6487 picoammeter to examine and analyze the bare device. Lastly, the diagnosis of dengue fever is performed by functionalizing the bio-receptor at the channel of the FET which is served as a molecular gate by the binding of a target DNA and monitoring electrical response to the concentrations of dengue virus. The device was tested repeatedly by using different concentrations of DNA target dengue. This step was performed to detect the sensitivity of the device. The device shows a wide-range of detection capability for detection of DNA dengue. The demonstrated results show that the FET has excellent properties for detection of dengue virus with outstanding sensitivity and selectivity properties.