Fetal bovine serum (fbs)

DNase, phorbol 12-myristate 13-acetate (PMA), and high molecular weight sodium hyaluronate were procured from Sigma-Aldrich. Chitosan (deacetylation degree of 95%) and sulfo-cyanine5.5 (Cy5.5) was procured from Energy Chemical (Shanghai, China). Sodium periodate (NaIO₄) was procured from KeLong Chemical (Chengdu, China). Anti-neutrophil elastase was procured from Abcam Co., Ltd. 4′,6-diamidino-2-phenylindole (DAPI), Bicinchoninic acid (BCA) kit, 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide (MTT), and nitric oxide (NO) probe were procured from Beyotime Biotechnology (Nantong, China). PE-labelled anti-CD86 antibodies and FITC-labelled CD80 antibodies were obtained from BioLegend. RAW264.7 cells were procured from the Shanghai Cell Bank (Shanghai, China) and were cultured in Dulbecco’s modified eagle’s medium with high glucose, supplemented with 10% heat-inactivated fetal bovine serum, 2 mM glutamine, nonessential amino acids, and sodium pyruvate. The medium and supplements were procured from Thermo Fisher Scientific. Cells were cultured at 37 °C in a humidified chamber with 5% carbon dioxide. The solvents used in the studies were analytically pure and used directly without treatment.