PAMAM-Graphene oxide-integrated microfiber sensor for label-free Dengue II E protein detection

We present a polyamidoamine-graphene oxide (PAMAM-GO) integrated microfiber sensor for the detection of Dengue virus II E protein (DENV II E protein). The microfiber was fabricated by heating a region of a single-mode optical fiber and pulling both ends at constant speed to achieve a diameter of 12 μm from 125 μm. The narrowing of the optical fiber diameter induced evanescent waves on the surface of the microfiber that interacted with the antibody/antigen complex adhered on the surface of the microfiber. The intensity of the interaction corresponds to the concentration of the antigen and can be quantified as a wavelength shift to the transmission spectrum. With the integration of PAMAM-GO, the sensor managed to achieve a sensitivity of 13.25 ± 0.2 nm/nM which is double the value achieved with a standard microfiber configuration. The overall performance of the sensor has potential towards improving dengue diagnostics today.