Label-free electrochemical immunosensor based on l-cysteine-functionalized AuNP on reduced graphene oxide for the detection of dengue virus E-protein in dengue blood serum

Abstract

Dengue fever is one of the most deadly viruses, and it has become a recurring public health problem in tropical areas. The increase in dengue cases worldwide has increased the demand for rapid and accurate diagnostic methods. In order to detect the content of dengue virus type E-proteins (DENV-E protein), we fabricated an efficient label-free electrochemical immunosensor platform that was constructed based on in situ reduction and functionalized gold nanoparticles decorated heteroatom-doped reduced graphene oxides nanocomposites (AuNPs/NSG). Here, L-cystein (L-cys) is introduced to green reducing and stabilizing agent of Au(III) and graphene oxide . The sensing platform offers a suitable higher number of antibody immobilization by providing L-cys. The highly crystalline AuNP was unfoirmly grafting on 2D graphene sheet . Under the optimized conditions, the as-designed immunosensor exhibited a wide linear working range from 0.01–100 ng mL −1 with a low detection limit of 1.6 pg mL −1 for DENV-E detection. The proposed immunosensor shows high selective for discriminating DENV-E against antibodies of their antibodies, including the closely related DENV. The reliability of fabricated immunosensor had been used to detect the viral E-protein contents in serum samples collected from patients, and obtained results were compared with the enzyme-linked immunosorbend assay. Furthermore, the developed AuNPs/NSG immunosensor can be used as a potential probe for future prospective clinical diagnostic applications. The electrochemical detection of dengue virus type E-proteins (DENV–E protein), the efficient label-free electrochemical immunosensor platform was constructed based on in situ reduction and functionalized gold nanoparticles decorated heteroatom doped reduced graphene oxides nanocomposites. The fabricated electrode exhibits lower detection limit and higher sensing and selective detection of DENV-E protein in dengue blood serum. • Label-free, highly selective, and an ultrasensitive label-free electrochemical immunosensor platform for DENV–E protein detection. • In situ reduction and functionalized AuNPs/NSG was synthesized via l -cysteine to achieve excellent electrochemical properties. • l -Cysteine on the nanocomposites to bind covalently with anti-DENV–E protein immobilization. • Immunosensor had a low detection limit of 1.6 pg mL −1 for DENV-E detection. • Successful detection of DENV–E protein in human blood serum samples.