CD44 and neoplasm: The HA gel shell can actively target CD44 expressed on tumor cells and depolymerize in response to the acidic TME and HAase, while TR@siSCD1 micelles can target PCa cells with the guidance of the RGD peptide and release siSCD1 in response to intracellular GSH and the proton sponge effect[2, 22, 27, 31] (Figures 1H and 2A).