Non-covalent loading of plant picovirus particles
Inventors
Steinmetz, Nicole • Popkin, Daniel
Assignees
Case Western Reserve University
Publication Number
US-12247228-B2
Publication Date
2025-03-11
Expiration Date
2034-02-18
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Abstract
A method of non-covalently loading a plant picornavirus is described. The method includes contacting a plant picornavirus in solution with a molar excess of a cargo molecule to load the plant picornavirus with the cargo molecule, and then purifying the loaded plant picornavirus. Examples of cargo molecules include imaging agents, antitumor agents, and antiviral agents. Loaded plant picornaviruses prepared in this manner can be used to delivering cargo molecule to cells.
Core Innovation
The invention describes a method for non-covalently loading plant picornavirus nanoparticles, especially cowpea mosaic virus (CPMV), with small cargo molecules such as imaging agents, antitumor agents, and antiviral agents. The method involves contacting a native plant picornavirus in solution with a significant molar excess—at least 500-fold—of the desired cargo molecule, relying on simple diffusion for loading, followed by purification of the loaded nanoparticle to remove unbound cargo. Cargo molecules may bind to the encapsulated nucleic acids within the virus particle via non-covalent interactions, or be trapped within the virus capsid through gating mechanisms, depending on their affinity for nucleic acids.
The background highlights challenges with existing drug delivery systems, noting that multistep chemical modifications used for loading cargos onto nanoparticles can be cumbersome, low-yielding, and costly. Plant-based viral nanoparticles offer advantages over synthetic materials, including safety profile, discrete structure, self-assembly, and modifiability. However, existing methods for loading cargos onto these carriers—particularly CPMV—often depend on complex chemistries. The disclosed method provides a simplified and efficient alternative that does not require covalent modification of the cargo or the use of intricate engineering steps.
The summary demonstrates that a variety of small molecules, including fluorescent dyes and therapeutic agents, can be efficiently infused into CPMV nanoparticles using this non-covalent approach. After loading and purification, these nanoparticles are capable of delivering their cargo molecules to target cells, including vimentin-expressing cancer cells. The method can optionally include chemical modification of the virus surface, such as PEGylation or attachment of targeting ligands, thus enabling cell-specific delivery while retaining the core simplicity and efficiency of the non-covalent loading technique.
Claims Coverage
The claims provide coverage for a nanoparticle comprising a native plant picornavirus non-covalently loaded with cargo molecules through specific infusion and purification steps, with further coverage for the types of cargo, virus modifications, and formulations.
Non-covalent infusion of cargo molecules into native plant picornavirus
A nanoparticle comprising a native plant picornavirus loaded with one or more cargo molecules, where the cargo is non-covalently infused into the interior of the virus by contacting the virus in solution with a molar excess of at least about 500-fold of the cargo molecule, with cargo loading achieved via simple diffusion and followed by purification of the loaded virus.
The claims primarily protect the process and product of non-covalently loading native plant picornavirus nanoparticles with small cargo molecules through diffusion, the resulting loaded nanoparticles, and their variants with specified cargoes, modifications, and formulations.
Stated Advantages
The method provides a simplified means of loading plant picornavirus nanoparticles without the need for multistep chemical modification procedures.
Cargoes loaded by non-covalent infusion are efficiently delivered to target cells and released, maintaining biological activity of the cargo molecule.
Plant picornavirus nanoparticles, such as CPMV, are non-pathogenic, non-toxic, and biodegradable in mammals, and are structurally stable under various conditions.
The approach enables high loading efficiency, preserves the chemical structure of the cargo, and allows for further chemical modification of the nanoparticle surface for targeted delivery.
Documented Applications
Delivery of imaging agents to cells, including use in imaging and detection of target cells in cell cultures, in vivo, or ex vivo.
Delivery of antitumor agents for killing or preventing the growth of cancer cells such as colon cancer, brain cancer, breast cancer, fibrosarcoma, and squamous carcinoma.
Delivery of antiviral agents to target cells such as dendritic cells and macrophages to treat persistent viral infections, including the use of PF-429242 to inhibit S1P-dependent viral replication.
Use of loaded plant picornavirus particles formulated as pharmaceutical compositions for therapeutic or imaging purposes, administered by various routes including parenteral and local applications.
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