siRNA Nanoparticle Delivery Strategies and Clinical Trial Advances in Tumor Therapy

siRNA, as a precise, specific, and highly effective gene-silencing therapy, has been extensively studied. Before reaching tumor cell targets, siRNA formulations must overcome multiple extracellular barriers, including clearance from the bloodstream, membrane impermeability, capture by the mononuclear phagocyte system (MPS), rapid renal excretion, endosomal escape, and precise recognition of target cells. These challenges limit siRNA’s clinical application. Consequently, various modifications have been applied to siRNA to enhance transfection efficiency, while researchers continue to pursue improved siRNA-targeting delivery systems. Nanotechnology offers a rational technical approach to address siRNA delivery. Nanoparticles can increase transfection efficiency while exhibiting lower cytotoxicity and reduced off-target effects. Various matrices have been employed to construct nanoparticles for targeted therapeutic delivery. This review briefly discusses siRNA nanoparticle delivery strategies, illustrates examples of various siRNA nanodelivery systems, such as lipid nanoparticles, polymeric siRNA nanoparticles, inorganic nanoparticles, hybrid nanoparticles, and conjugate-siRNA delivery systems, and introduces clinical trials of siRNA-loaded nanoparticles for cancer treatment, which can provide valuable references for further research and clinical application of siRNA nanoparticle delivery systems.