Methyl thiazolyl tetrazolium (mtt)

Cocoons of Bombyx mori (silkworm) were provided by the College of Textile and Clothing Engineering, Soochow University. Chitosan powders with molecular weight about 900 000 Da and 95% degree of deacetylation were purchased from Jiangsu Aoxin Biotechnology Co., Ltd. Gelatin, sodium carbonate, lithium bromide, acetic acid, aqueous ethanol, polyethylene glycol 6000, dimethylsulfoxide (DMSO), MTT, 4% paraformaldehyde, hematoxylin, eosin, crystal violet, and dialysis bags were obtained from Shanghai Yuanye Biotechnology Co., Ltd. Ethylene dichloride (EDC) and N-Hydroxysuccinimide (NHS) were acquired from Adamas Reagent, Ltd. MEM, FBS, and penicillin–streptomycin were bought from Thermo Fisher Scientific Inc.

Mtx was purchased from Yuanye Biotechnology (Shanghai, China). PLGA was purchased from Boehringer Ingelheim Pharma (Ingelheim am Rhein, Germany). DMEM was purchased from Thermo Fisher Scientific (Waltham, MA, USA). Lipopolysaccharide (LPS) and polyvinyl alcohol (87%–89% hydrolyzed, molecular weight [MW] 13,000–23,000 Da) were purchased from Sigma-Aldrich (St Louis, MO, USA). fetal bovine serum (FBS) and RAW264.7 cells were obtained from Procell Biological Technology (Wuhan, China). 4′,6-diamidino-2-phenylindole (DAPI) was obtained from Beyotime Institute of Biotechnology (Haimen, China). Rhodamine B was obtained from Sinopharm Chemical Reagent (Shanghai, China). Acetonitrile was purchased from Thermo Fisher Scientific. MTT was obtained from Yuanye Biotechnology. Enzyme-linked immunosorbent assay (ELISA) kits for TNFα and IL6 were obtained from Elabscience Biotechnology (Wuhan, China). Complete Freund’s adjuvant was obtained from Chondrex (Redmond, WA, USA). All chemicals used were of analytical grade and used without further purification.