Provided herein is a method for stabilising a single stranded RNA (ssRNA) by encapsidation of the ssRNA with a tobamovirus coat protein to obtain a pseudovirion (PsV), the method comprising expressing a tobamovirus coat protein and the ssRNA comprising a tobamovirus encapsidation origin (OriA), wherein the expressed tobamovirus coat protein interacts with the OriA sequence on the ssRNA to initiate encapsidation of the ssRNA by the tobamovirus coat protein, thereby forming a pseudovirion. The PsVs produced according to the method can be used as a diagnostic control composition, where the ssRNA is a sequence detected by a molecular diagnostic assay. The pseudovirions may also be used as a vaccine to elicit an immune response in a subject, and in pharmaceutical compositions to be administered to a subject.

The present disclosure generally relates to nucleic acid molecules for use in regulating gene expression. Disclosed herein include nucleic acid molecules containing one or more structural elements of the viral capsid enhancer operably linked to a coding sequence of a gene of interest. In some embodiments, the viral capsid enhancer comprises a Downstream Loop (DLP) from a viral capsid protein, or a variant of the DLP.

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.

This application relates in part to nanoparticles comprising a tobamovirus and nanoparticles comprising a tobamovirus and beta-cyclodextrin (-CD or BCD). This application also relates in part to nanoparticles comprising tobamovirus and one or more active ingredients (AIs) that are non-covalently conjugated to the tobamovirus. The application also provides methods of making and methods of using such nanoparticles as well as compositions comprising the disclosed nanoparticles.