Enhanced detection of infectious pancreatic necrosis virus via lateral flow chip and fluorometric biosensors based on self-assembled protein nanoprobes.

Salmon fish farmers face remarkable problems in fish rearing and handling due to the spread of disease by infectious pancreatic necrosis virus (IPNV). Therefore, we developed a straightforward and sensitive technique to detect IPNV based on recombinant human apoferritin heavy chain (hAFN-H) protein nanoparticles. In this study, the 24 subunits of the hAFN-H were genetically modified to express 6×His-tag and protein-G at their C-terminal site, using Escherichia coli. We thus achieved a two-step signal amplifying strategy that utilizes a recombinant hAFN-H nanoprobe having a protein-G-binding site that targets the Fc region of monoclonal antibodies, and a 6×His-tag that actively interacts with the functionalized Ni-NTA derivatives. In this study, we report a considerable advancement in magnetic bead-based detection systems that use Ni-NTA-atto 550, reliably exhibiting detection limits of 1.02 TCID50/mL (50 % tissue culture infective dose). Additionally, we propose a lateral flow chip-based detection method that uses the hAFN-H surface functionalized with 5 nm of the Ni-NTA-nanogold complex as a nanoprobe; the limit of detection towards IPNV was 0.88 TCID50/mL. The detection of IPNV by this recombinant hAFN-H nanoprobe was linear to virus titers in the range of 101-103 TCID50/mL.