Anomalous Fluorescence Dynamics Emerge in Densely Labeled Virus-Like Particles

The symmetric protein cage of the brome mosaic virus provides a relatively rigid, chemically addressable, deterministic molecular scaffold capable of being covalently labeled with organic dyes at high densities, with the overall scaffold structure remaining intact. Homogeneous short interchromophore distances endow the dye-decorated cage with network-like connectivity that supports efficient energy flow. Network connectivity varies in time in a way that is determined by the relative rates of reversible and irreversible phenomena, including Förster resonant energy transfer, prototropism, and photobleaching. Through a combined experimental and computational analysis, we disentangle these effects and advance a simplified model that reveals the role of the virus shell scaffold in shaping the fluorescence dynamics, which is distinct from those of other luminescent nanoparticles.