Schematic illustration of P/B-COS NPs delivery during radiofrequency ablation. (a) Radiofrequency ablation with cold saline irrigation, the drugs contained in saline can enter local tissues. (b) Schematic illustration of P/B-COS NPs preparation. NPs were prepared by an oil-in-water emulsion solvent evaporation method and COS was attached to the surface of PLGA NPs by amide bonds. (c) The rapid increased local temperature generated by ablation exceeds the transition temperature of PLGA, resulting in the release of BUD. Nanoparticles infiltrated into local tissue and continued BUD release and anti-inflammatory effect in the following days.