Phototriggered cargo release from virus-like assemblies.

There has been tremendous progress towards the development of responsive polymers that are programmed to respond to an external stimulus such as light, pH and temperature. The unique combination of molecular packaging followed by slow, controlled release of molecular cargo is of particular importance for self-healing materials and the controlled release of drugs. While much focus and progress remains centred around synthetic carriers, viruses and virus-like particles can be considered ideal cargo carriers as they are intrinsically designed to package, protect and deliver nucleic acid cargo to host cells. Here, we report the encapsulation of a stimuli-responsive self-immolative polymer within virus-like assemblies of Cowpea Chlorotic Mottle Virus. Upon photo-irradiation, the self-immolative polymer undergoes a head-to-tail depolymerization into its monomeric subunits, resulting in the slow release of the molecular cargo. We propose that the liberated monomers are small enough to diffuse through the pores of the virus capsid shell and offer an alternative strategy for the controlled loading and unloading of the molecular cargo using viruses as cargo carriers.