Preparation and Evaluation of Upconversion Nanoparticles Based miRNA Delivery Carrier in Colon Cancer Mice Model

Therapeutic efficacy of solid tumor is often severely hampered by poor penetration of therapeutics into diseased tissues and lack of tumor targeting. In this study, the functionalized upconversion nanoparticles (UCNP)-based delivery vector targeting cancer cells was developed. Firstly, NaYF₄:Yb/Tm (UCNP) was prepared with the solvothermal method for the uniform nanoparticle size and brilliant lattice structure. The SiO₂ coated UCNP was demonstrated a high upconversion emission and good monodispersity, which was coupled with polyetherimide (PEI) and miR-145 vector. Then, it was further functionalized via hyaluronic acid (HA) (UCNP/PEI/HA Nanocomplex, UCNPs) coating for the targeted delivery and improved biocompatibility. The UCNPs/miR-145 displays an excellent biocompatibility, a high level of cellular uptake and miR-145 expression, which results in a significant cell cycle arrest in G1, and induces CCND1, CDK6 and CCNE2 proteins downregulation. In vivo, the HA-coated UCNPs were enriched at the tumor site by targeting and retention effects, which resulted in a significant inhibition of tumor growth. Histological experiments demonstrated that UCNPs did not show significant toxicity in mice colon cancer model. Taken together, a UCNPs-based delivery platform was successfully constructed and used for miRNA target delivery, which provided a new method and idea for bioengineering and nanotechnology-based tumor therapy.