点击放大Y型-双臂-甲氧基-聚乙二醇-NHS活性酯（n=8）Y-(mPEG8)2-NHS; Y-shaped bis(methoxy-poly(ethylene glycol)) with a single N-hydroxysuccinimide ester conjugation handle (PEG arm n=8)
点击放大环状聚乙二醇-聚乙二醇臂-NHS活性酯（n=6）40-crown-13-PEG6-CH2COONHS Ester; N-hydroxysuccinimide ester-terminated PEG arm on a cyclic poly(ethylene glycol) scaffold (arm n=6)
