Laser-Induced Graphene Modified with Gold Nanoparticles for Dengue Biomarker Detection: Toward Portable and Flexible Biosensing Platforms for Early Diagnosis

Abstract Dengue remains a major public health challenge in tropical and subtropical regions, where early detection can support timely clinical management. Nonstructural protein 1 (NS1), released during the acute phase of infection, is an important biomarker for early dengue detection. Here, we report a flexible electrochemical immunosensor based on laser-induced graphene (LIG), a hierarchically porous three-dimensional carbon material produced by laser irradiation of polyimide and functionalized with gold nanoparticles (AuNPs) through a simple electroless deposition process. The incorporation of AuNPs reduced the impedance of the LIG electrode, enhanced interfacial charge transfer, and increased the electrochemically accessible surface area. Structural, morphological, electrochemical, and surface wettability characterizations confirmed the successive modification steps of the sensing platform. The resulting biosensor exhibited a logarithmic response to DENV-2 NS1 over the experimentally evaluated concentration range of 10–1000 ng/mL, with a calculated limit of detection of 3.3 ng/mL. The sensor showed reproducible responses and low cross-reactivity toward Zika virus NS1 under the investigated conditions. These results demonstrate the feasibility of combining porous LIG and AuNPs for electrochemical NS1 detection and provide a basis for the further development of flexible electrochemical biosensors for dengue NS1 detection.