15209
2 ' , 4 ' - BNA / LNA aptamers : CE - SELEX using a DNA - based library of full - length 2 ' - O , 4 ' - C - methylene - bridged / linked bicyclic ribonucleotides .
 Chemical: 2 ' - O , 4 ' - C - methylene - bridged / linked bicyclic ribonucleotides
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: 2 ' - O , 4 ' - C - methylene - bridged / linked bicyclic ribonucleotides