Understanding And Applying Anisotropic Virus Particle Transport In Complex Media

Advances in nanotechnology have improved medical diagnostics. For nanoparticle-based diagnostics, nanoparticle transport significantly impacts assay performance, especially for assays involving complex medical samples. Existing diffusion models for spherical nanoparticles are often used to predict transport in complex media, but the diffusion of anisotropic nanoparticles is not well understood. Previous work in our group has demonstrated the effectiveness of highly-anisotropic filamentous viruses as diagnostic reporters. We studied the diffusion of filamentous viral nanoparticles in model polymer solutions using fluorescence microscopy and particle tracking analysis. The extracted virus dynamics were then compared with existing theories to determine which virus properties control virus diffusion. Our results indicate that virus anisotropy influences viral particle dynamics and enhances virus diffusion compared to spherical nanoparticles. We also investigated the use of bacteriophage M13 in a reporter-exclusion immunoassay. We use the restricted-access adsorbent CaptoTM Core 700 to capture reporter molecule enzyme-antibody conjugate. By introducing M13 as a large binding scaffold, small protein hCG can be detected as the M13-analyte-reporter complex is excluded from the resin in the presence of analyte. Our results demonstrate the proof-of-concept and potential of this type of assay for a wide range of applications. Understanding the transport properties of filamentous viruses will be critical for future development and implementation of virus-based diagnostics.