Nanoparticles for expression of genes of interest and/or regulation of signaling pathways

The disclosure provides methods and compositions for delivering RNA constructs to cells for functional expression and/or activity. In some aspects, the disclosure provides a composition comprising a multi-functionalized nanoparticle. The multi-functionalized nanoparticles comprise a core functionalized with at least one RNA molecule, at least one cell penetrating peptide (CPP), and at least one positively charged moiety, each of which is independently attached to the core, optionally with linker moieties. In some embodiments, the RNA molecule is an uncapped mRNA molecule with the 5' end attached to a linker moiety that is attached to the core. The multi-functionalized nanoparticle is substantially neutral, negatively or positively charged. The multi-functionalized nanoparticle can be used in methods of delivering and causing the expression of polypeptides of interest in a cell for various purposes, including vaccination, cancer treatment, extension of telomeres, modification of cellular signaling pathways, and the like.