Fabrication of fluidic-based memristor sensor for dengue virus detection

In this paper, the implementation of fluidic-based memristor sensor in bio-sensing application is presented. The sensor was fabricated using sol-gel spin coating technique and chemically-modified with antidengue virus NS1 glycoprotein monoclonal antibody before being presented with its ligand, NS1 glycoprotein. Four different concentrations of NS1 glycoprotein (52 nM, 104 nM, 208 nM and 416 nM) were tested on the modified sensor. Each sensor has nine wells, which function to increase the binding area for trapping more viral proteins. To test whether the efficiency of the sensor is attributed by the surface area of each well, four different diameters of the well were fabricated: 0.5 mm, 1 mm, 1.5 mm and 2 mm. These sensors were characterized using field emission scanning electron microscope (FESEM) and semiconductor characterization system (current-voltage (I-V)). FESEM images of the wells show different surface morphologies prior to biochemical treatment, after the bound-antibody modification and after the presentation of viral protein. Off-on resistance ratio extracted from I-V curve between the antibody-bound sensor with and without the viral protein. Analysis shows that the loop area increases as the NS1 glycoprotein applied to the modified sensor. The area within the loop also increases as the concentration of the NS1 glycoprotein increases. The most significant change in loop area is observed upon introduction of 416 nM. Memristor sensor with 2 mm-well diameter recorded the highest sensitivity when compared to the other three well diameters. The recorded sensitivity for the 2 mm-well diameter is 6.53 × 10⁻³ nM⁻¹ according to fluidic-based platform. These findings conclude that specific-binding between dengue virus antibody and NS1 glycoprotein of dengue virus can be detected by the sensor via the change in electrical conductivity.