[Fabrication of chitosan/hyaluronic acid complex nanoparticles for effective siRNA delivery].

The development of safe and effective carriers is crucial for improving the <i>in vivo</i> stability of siRNA drugs and facilitating their clinical translation. Chitosan (CS), a natural cationic polymer, shows great potential in nucleic acid drug delivery. To optimize the physicochemical properties of CS/siRNA nanoparticles (NPs) and increase their siRNA delivery efficacy, in this study, hyaluronic acid (HA) was added into CS to form stable complex NPs through electrostatic interactions. The HA component is able to target the CD44 receptors on the surface of tumor cells, facilitating efficient siRNA delivery. First, we systematically investigated the effects of the molecular weights and mass ratio of CS and HA on the physicochemical properties of CS/HA NPs. The results showed that at HA: CS mass ratios of approximately 5:5 and 6:4, the complex NPs exhibited small particle sizes, narrow size distribution, and high storage stability. Under similar conditions, the size of CS/HA NPs increased with the increase in the molecular weights of CS and HA. Based on these findings, suitable conditions were selected to prepare CS/HA NPs for siRNA delivery. Cell experiments demonstrated that the introduction of HA effectively reduced the cytotoxicity of the CS delivery system and enhanced the NP uptake. The CS/HA/siRNA NPs achieved 50% to 60% silencing of the luciferase gene in HeLa-Luc cells. CS/HA NPs formed smaller nanoparticles with siRNA than pure CS and mediated specific interactions with tumor cells <i>via</i> HA, leading to efficient siRNA delivery. These findings provide valuable insights into the construction of natural polymer composite nanoparticles for application in siRNA delivery.