Due to the presence of disulfide bond in the Meo‐PEG‐S‐S‐PLGA copolymer, these NPs show a reduction‐responsive characteristic, as demonstrated by increased particle size, destroyed nanostructure, and fast drug release in the presence of GSH at a concentration (e.g., 10 × 10−3m) closed to the level in tumor cells (Figure S15, Supporting Information).[34, 35] More importantly, the NPs(siCFL1/Sor) could efficiently down‐regulate CFL1 expression by ≈80% in MHCC‐97L cells at a siCFL1 dose of 30 × 10−9m (Figure 6D,E). This evidence concerns the gene CFL1 and neoplasm.