点击放大双臂-聚乙二醇-NHS活性酯（n=12）2-Arm-PEG-CH2CH2COONHS Ester (n=12, per arm); 2-Arm N-hydroxysuccinimide ester-functionalized discrete poly(ethylene glycol) (PEG arm n=12)
点击放大环状聚乙二醇-聚乙二醇臂-NHS活性酯（n=12）76-crown-25-PEG12-CH2COONHS Ester; N-hydroxysuccinimide ester-terminated PEG arm on a cyclic poly(ethylene glycol) scaffold (arm n=12)
