Application of a graphene-oxide-modified surface plasmon resonance biosensor in dengue E-protein detection

The sensitization effect of graphene oxide (GO) on surface plasmon resonance (SPR) chip sensors has been widely reported. However, the absence of a fixed value for selecting the GO solution concentration is a significant limitation for reproducing the experiments reported in the literature. In this study, linear functionalized polyethylene glycol (SH-PEG-NH2) is used to modify the surfaces of bare gold chips, using flow and immersion methods to produce GO-film-covered SPR sensor chips. Deionized water and phosphate buffered saline are applied as refractive index variants to compare the changes in sensor performance following chip modification, and to determine the optimal concentrations of GO solution under the respective modification methods. Using a sensor chip modified with the optimal GO concentration enhances the ability of a 10-year-old device to detect the dengue virus (DENV) E-protein by 357% and enables the detection of antibody protein concentrations as low as 62.5 ng/mL. Satisfactory results were also obtained using a DENV-positive serum to verify the chip usage. The results of this study are of significance for future efforts involving the rapid preparation of accurate and low-cost GO-SPR biosensor chips.