MoS₂/carbon nanotubes nanocomposite thin films as platform for electrochemical dengue detection

Sensitive electrochemical immunosensors are important for addressing global health challenges, particularly for the rapid and affordable diagnosis of infectious diseases such as dengue fever. This work reports the preparation and characterization of molybdenum disulphide/carbon nanotubes (MoS₂/CNT) thin films, obtained through the liquid-liquid interfacial route, and their application as active materials in an electrochemical immunosensor for the detection of dengue virus nonstructural protein 1 (NS1), a key biomarker for early diagnosis. The nanocomposites were prepared starting from two different MoS₂ samples (laboratory-synthesized or commercial) and characterized by scanning electron microscopy (SEM), X-ray diffractometry (XRD), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The film based on laboratory-synthesized MoS₂ exhibited smaller flakes, higher surface area and superior electrochemical performance compared to the commercial ones. For the immunosensor assembly, a stencil-printed, lab-made electrode was coated with the MoS₂/CNT film, followed by antibody/BSA immobilization. A label-free detection mode was adopted, and under EIS conditions, a log-linear dynamic range of 4-1000 ng mL^-1 and a low detection limit of 8 ng mL^-1 were achieved. High selectivity was confirmed against other arboviruses (Chikungunya and Yellow Fever), and reliable performance was achieved in diluted human serum. The proposed MoS₂/CNT thin-film is a promising platform for the future development of low-cost, miniaturized, and sensitive point-of-care diagnostic devices for dengue and related infectious diseases.