Metal (Au, Pt) Nanoparticle–Latex Nanocomposites as Probes for Immunochromatographic Test Strips with Enhanced Sensitivity

The development of a sensitive and rapid diagnostic test for early detection of infectious viruses is urgently required to defend against pandemic and infectious diseases including seasonal influenza. In this study, we developed noble metal (Au, Pt) nanoparticle-latex nanocomposite particles for use as probes for immunochromatographic test (ICT) strips. The nanocomposite particles were conjugated with monoclonal antibody (mAb) to detect an influenza A (H1N1) antigen. For comparison, Au nanoparticles conjugated with mAb were also prepared. The lowest detectable concentrations of the influenza A antigen were found to be 6.25 × 10 -3 and 2.5 × 10 -2 HAU/mL for Au nanoparticle-latex and Pt nanoparticle-latex nanocomposite particles, respectively, whereas it was 4.0 × 10 -1 HAU/mL for Au nanoparticles. These results clearly demonstrated that the nanocomposite probes were more sensitive than conventional nanoparticle-based probes for ICT. To expand the versatility of the nanocomposite probes, the surfaces of the probes were functionalized with biotinylated proteins to enable modification of their surfaces with desired biotinylated antibodies through biotin-avidin binding.