点击放大环状聚乙二醇-聚乙二醇臂-羟基（n=4）28-crown-9-PEG4-OH; Hydroxyl-terminated PEG arm on a cyclic poly(ethylene glycol) scaffold (arm n=4)
点击放大双臂-聚乙二醇-羟基（n=4）2-Arm-PEG-OH (n=4, per arm); 2-Arm hydroxyl-functionalized discrete poly(ethylene glycol) (PEG arm n=4)
点击放大四臂-聚乙二醇-羟基（n=4）4-Arm-PEG-OH (n=4, per arm); 4-Arm hydroxyl-functionalized discrete poly(ethylene glycol) (PEG arm n=4)
点击放大六臂-聚乙二醇-羟基（n=4）6-Arm-PEG-OH (n=4, per arm); 6-Arm hydroxyl-functionalized discrete poly(ethylene glycol) (PEG arm n=4)
