Functionalised Biosensor for Diagnostics of Dengue NS1 Antigen : An Integrated Approach Towards Device Development

Dengue, which is one of the rapidly spreading disease, through mosquitoes as carriers, poses challenges to biosensor developers, since the detection has to be rapid and very specific. A non-invasive microwave-based complementary split ring resonator (CSRR) sensor is proposed to detect the dengue NS1 antigen. An electronic antenna structure is etched out of copper, on the ground plane of a micro-strip or transmission line using a printed circuit board (PCB) method on the FR4 substrate. A micro-strip transmission line coupled with CSRR acts as a sensor whose sensing mechanism is based on the interception of the electromagnetic field around the resonator, which leads to a shift in the resonance frequency. To detect dengue NS1 antigen, the sensor is functionalized with the antibody of NS1 using 1-(3- dimethylaminopropyl)- 3-ethylcarbodiimide hydrochloride (EDC) as the linker molecule. Upon immobilizing NS1 antibody on the CSRR structure, the sensor offers high sensitivity in the form of a change in the power of the signal due to antigen-antibody interaction. The sensor shows a power shift of ~24dB for 10 μl of dengue NS1 antigen. A highly sensitive sensor is hence demonstrated using careful simulation studies, electronic device development and use of nanotechnology for improved performance.