Encapsidation of nanoparticles in virus-like particles: Opportunities and biomedical challenges

This review states an overview of the encapsidation of nanoparticles (NPs) in virus-like particles (VLPs) of various viral origins, with their functionality in drug delivery and biomedical imaging. Compared with traditional delivery vehicles such as liposomes and dendrimers, VLPs have shown improved stability, biocompatibility, and targeting specificity with their inherent self-assembling capsid structure. Encapsulated NPs also illustrate protection against degradation and aggregation, enhanced bioavailability, and regulated release, which overcome primary limitations of conventional NP-based drug delivery strategies. Functionalized NPs like gold NPs and quantum dots are stabilized and characterized particularly when they are encapsulated in viral capsids that allow imaging techniques like computed tomography (CT), magnetic resonance imaging (MRI), positron emission tomography (PET), and optical fluorescence. VLPs also facilitate theragnostic as well as therapeutic uses, such as in VP4 rotavirus VLPs for encapsulating doxorubicin and iron oxide NPs in cancer treatment. Synthesis methods for VLPs, such as heterologous expression and assembly in vitro, are presented with particular attention to control of the physicochemical parameters to maximize encapsidation yield. Characterization methods like transmission electron microscopy (TEM), dynamic light scattering (DLS), and fluorescence assays are used to establish particle integrity and measure loading. While the VLPs encapsidated NPs display promising attributes, challenges are associated with them, such as immunogenicity due to viral proteins and the requirement for immune evasion strategies like PEGylation. The review highlights the mechanisms of VLPs encapsidated NPs as multifunctional platforms combining viral natural targeting with NPs features to propel precision medicine and diagnostic imaging.