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异官能团双取代聚乙二醇(PEG)衍生物是绝佳的连接剂，其片段具有水溶性、生物相溶性、灵活性。以下是异官能团双取代的典型结构式：
NH2-PEG-COOH
mPEG-OH
mPEG-NH2
mPEG-COOH
mPEG-NHS
AA-PEG-AA (AA-Acetic Acid)
OH-PEG-OH
AC-PEG-AC (AC-Acrylate)
NCO-PEG-NCO
SAA-PEG-SAA (SAA-Succinamide Acid)
GAA-PEG-GAA (GAA-Glutaramide Acid)
MA-PEG-MA (MA-Methacrylate)
GA-PEG-GA (GA-Glutaric Acid)
VS-PEG-VS (VS-Vinyl Sulfone)
CHO-PEG-CHO
COOH-PEG-COOH
SH-PEG-SH (SH-thiol)
Alkyne-PEG-Alkyne
Azide-PEG-Azide
NH2-PEG-NH2
SA-PEG-SA (SA-Succinic Acid)
SS-PEG-SS (SS-Succinimidyl Succinate ester)
Br-PEG-Br
HZ-PEG-HZ (HZ-Hydrazide)