点击放大环状聚乙二醇-聚乙二醇臂-马来酰亚胺（n=16）100-crown-33-PEG16-Mal; Mal-terminated PEG arm on a cyclic poly(ethylene glycol) scaffold (arm n=16)
点击放大Y型-双臂-甲氧基-聚乙二醇-马来酰亚胺（n=16）Y-(mPEG16)2-Mal; Y-shaped bis(methoxy-poly(ethylene glycol)) with a single Mal conjugation handle (PEG arm n=16)
