19173
We found that TiO2 NPs ( diameter < 25 nm and < 100 nm ) in anatase crystalline can covalently interact with liver DNA by either inserting itself in between DNA base pairs or binding to DNA nucleotide via P - O - Ti - O bond .
 TiO2, nucleotide, O - Ti - O
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Chemical 
Text: {0} 
Answer:
 TiO2, nucleotide, O - Ti - O