A method of treating cancer in a subject in need thereof includes administering in situ to the cancer a therapeutically effective amount of a virus or virus-like particle.

An in vitro process of preparing virus-like particles (VLPs) from recombinant papaya mosaic virus coat protein and ssRNA, which allows for large scale production of VLPs in high yields, is provided. Also provided are VLPs comprising ssRNA prepared by the in vitro process. The VLPs can be used as adjuvants and when fused to an antigen, as vaccines. The use of the VLPs for stimulation of the innate immune response is also provided.

A method of treating cancer in a subject in need thereof includes administering in situ to the cancer a therapeutically effective amount of a virus or virus-like particle.

A method of treating cancer in a subject in need thereof includes administering in situ to the cancer a therapeutically effective amount of a virus or virus-like particle.

A method of treating cancer in a subject in need thereof includes administering in situ to the cancer a therapeutically effective amount of a virus or virus-like particle.

An intratumoral immunotherapy for treating cancer in a subject in need includes a therapeutically effective amounts of cowpea mosaic virus (CPMV), CPMV virus-like particles, potato virus X (PVX), and/or PVX virus-like particles formulated for in situ administration to cancer of the subject, wherein the therapeutically effective amount of CPMV, CPMV virus-like particles, PVX, and/or PVX virus-like particles is an amount effective to provide a durable and systemic anticancer response against cancer metastasis and recurrence in the subject, and the CPMV, CPMV virus-like particles, PVX, and/or PVX virus-like particles are not used as a vehicle for drug or antigen delivery.

A method for functionalizing plant viral nanoparticles (VNPs) includes selecting a plant VNP. Additionally, a metal ion and a phenolic compound that form a metal-phenolic network (MPN), and at least one functional component that adheres to the MPN are also selected. A nanohybrid structure is synthesized from a solution of the selected metal, the selected phenolic compound and the selected functional component such that the synthesized nanohybrid structure has an MPN coating encapsulating the plant VNP with the functional component being embedded in the MPN coating.