document: used as a protein expression reagent at an OD600nm of 0.8-1.0 in LB broth. The IPTG-supplemented culture was incubated at 37 ℃ overnight for approximately 16-18 h. The overnight culture was harvested by centrifugation at 6,500 g, resuspended in 20 mL of PBS buffer (pH=7.4) and then lysed by sonication. The lysate was centrifuged for 30 min at 23,000 g, followed by ammonium sulfate precipitation, which was used to obtain crude VLPs. Crude VLPs were resuspended in PBS buffer, followed by 20% w/v