22397
The resulting acoustic radiation force allowed us to locally trap particles / cells , including 15 mu m polystyrene beads and HeLa cells , around each bubble .
 Chemical: polystyrene
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: polystyrene