12513
Dehydration of DOPC / DOTAP ( 70 / 30 ) and DOPC / DC - Ch ( 70 / 30 ) was observed in the presence of mRNA but not in the case of zwitterionic DOPC liposomes , indicating that mRNA binds in regions between the phosphate [ - PO ( 2 ) ( - ) - ] and carbonyl [ - C = O - ] moieties of lipids .
 DOPC, DOTAP, DOPC, DC - Ch, DOPC, phosphate, PO ( 2 ) ( - ), carbonyl, C = O
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Chemical 
Text: {0} 
Answer:
 DOPC, DOTAP, DOPC, DC - Ch, DOPC, phosphate, PO ( 2 ) ( - ), carbonyl, C = O