Furthermore, our study demonstrates the long-term stability of mRNA-PEI encapsulated within mRPZ at varying temperatures, which may be advantageous for mRNA vaccine storage and transportation. While ZIF-8 coating improves the stability of the mRNA-PEI complex, mRNA expressibility still decreases with storage time. Overall, our findings present a ZIF-8-based delivery system as a promising candidate for mRNA therapeutics, particularly vaccines, offering enhanced stability, efficient delivery, and prolonged-expression kinetics. Future work exploring immune responses and improving the colloidal stability of mRPZ is needed.