6217
This system is used to investigate the lateral diffusion of 40 nm gold spheres tethered to biotinylated lipids through antibody - functionalized ligands ( single - stranded DNA or polyethylene glycol ) .
 Chemical: polyethylene glycol
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: polyethylene glycol