29646
A better understanding of this free PEI - induced attractive force will be useful in the development of improved PEI / DNA polyplexes systems for biomedical applications .
 Chemical: PEI; 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; Chemical: PEI