Hematoxylin

Cocoons of Bombyx mori (silkworm) were procured from farmers in Xuzhou, Jiangsu. Cs powders (900 000 Da, 95% deacetylated) were purchased from Shanghai Macklin Biochemical Technology Co. Ltd. Alg, sodium carbonate, lithium bromide, acetic acid, aqueous ethanol, polyethylene glycol 6000, dimethyl sulfoxide, cell counting kit (CCK)-8, 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 bought from Sangon Biotech (Shanghai) Co. Ltd. Minimum essential medium culture media, fetal bovine serum, and penicillin–streptomycin were bought from Thermo Fisher Scientific Inc. (Waltham, MA). Four-week-old female BALB/c-nu mice were purchased from the Animal Center of East China Normal University. Mice were bred and maintained under specific-pathogen-free conditions. The study was approved by the Hospital Ethical Committee (2019 JS-004, Shanghai Fifth People’s Hospital), and all methods used in this study were carried out following the Regulations for the Administration of Affairs Concerning Experimental Animals approved by the State Council of the People’s Republic of China. Commercially available human CC cells HCT-116 (1×10⁷ cells/0.1 mL per site) were injected subcutaneously in the left underarm and right inguinal area of mice.

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.

CRC cells grown on coverslips were fixed with 4% (wt/vol) paraformaldehyde (PFA; Sangon Biotech, Shanghai, China) for 15 min and stained with 3 mg/mL Oil Red O solution (Yuanye, Shanghai, China) for 30 min. After nuclear counterstaining with hematoxylin (Yuanye, Shanghai, China), lipid droplet was visualized under a microscopy (Olympus, DP73, Tokyo, Japan) and evaluated using Image J software (National Institutes of Health, Bethesda, USA).
Similarly, CRC cells grown on coverslips were fixed with 4% (wt/vol) PFA for 15 min and stained with 2 μmol/L Nile Red solution (Solarbio, Beijing, China) for 30 min. Subsequently, the nuclei were stained with 4,6‐diamidino‐2‐phenylindole (DAPI; Thermo Fisher Scientific, Waltham, USA), and immunofluorescence signals were visualized under confocal microscopy (ZEISS, LSM880, Oberkochen, Germany).