20839
After being coated with zwitterionic dopamine sulfonate molecules , the 4 . 8 nm GdIO nanoparticles showed a steady hydrodynamic diameter ( ~ 5 . 2 nm ) in both PBS buffer and fetal bovine serum solution , indicating a low nonspecific protein absorption .
 dopamine sulfonate, GdIO
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Chemical 
Text: {0} 
Answer:
 dopamine sulfonate, GdIO