A new method has been developed to improve the detection of norovirus (NoV) in complex fecal samples using nanomaterials-based immunoassays. The method involves using multifunctional trimetallic nanoparticles, known as Ag@Fe3O4@Au NPs. These nanoparticles consist of a core of silver (Ag) and a shell of iron oxide (Fe3O4) decorated with isolated gold (Au) nanoparticles. The nanoparticles have enhanced catalytic activity, making them an ideal nanocatalyst for reducing substrate molecules. The developed Ag@Fe3O4@Au NPs-based immunoassay achieved a limit of detection (LOD) of 1.9 pg/mL for norovirus-like particles (NoV-LP) and 6.97 fecal NoV copy number/mL. Achieving a LOD under 10 copy numbers is important for detailed protein analysis. The study also found that heat treatment of fecal suspension at 65°C was necessary to prevent the degradation of the target analyte for sensitive NoV detection. This work successfully combined multifunctional nanocatalysts for advanced immunoassays, which could contribute to developing nano-biosensing platforms.

Development of disposable, rapid and convenient biosensor with high sensitivity and reliability is the most desired method of viral disease prevention. To achieve this goal, in this work, a practical impedimetric biosensor has been implemented into a disposable electrode on a screen-printed carbon electrode (SPCE) for the detection of two mosquito-borne viruses. The biosensor fabrication has step-wisely carried out on the disposable electrode surface at room temperature: starting from conductive film formation, physical binding of the gold nanoparticles (AuNPs)-polyaniline (PAni) into the conductive film, and biofunctionalization. To get the maximum efficiency of the antibody, biotinylated antibody has been conjugated on the surface of AuNP-PAni /PAni-SPCE via the streptavidin-biotin conjugation method which is a critical factor for the high sensitivity. Using the antibody-antigen interaction, this disposable electrode has designed to detect mosquito-borne infectious viruses, Chikungunya virus (CHIKV) and Zika Virus (ZIKV) separately in a wide linear range of 100 fg/mL to 1 ng/mL with a low detection limit of 1.33 fg/mL and 12.31 fg/mL, respectively.