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The G2 . 5 - PEI 423 complexes display much higher transfection efficiencies than PAMAM G5 and Lipo - 2k , and the G1 . 5 - PEI 423 complexes display higher transfection efficiencies than PAMAM G4 and PEI - 25k .
 Chemical: PEI 423; Chemical: PAMAM; Chemical: PEI 423; Chemical: PAMAM; Chemical: PEI
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
 Chemical: PEI 423; Chemical: PAMAM; Chemical: PEI 423; Chemical: PAMAM; Chemical: PEI