18507
The resulting nanoparticles ( M - PEG - HANPs ) had a smaller size ( 153 . 7 +/- 4 . 5nm ) than bare PEG - HANPs ( 265 . 1 +/- 9 . 5nm ) , implying that mineralization allows the formation of compact nanoparticles .
 Chemical: PEG; Chemical: PEG
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: PEG; Chemical: PEG