7905
We anticipate that acid - degradable PKAA has great potential as siRNA carriers based on its excellent biocompatibility , pH sensitivity , potential endosomolytic activity , and high delivery efficiency .
 Chemical: PKAA
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: PKAA