10893
By using reversible hydrogenation of graphene and binding of streptavidin - biotin , we demonstrate an areal mass sensitivity at a level of fg mm ( - 2 ) and detection of individual biomolecules , respectively .
 Chemical: graphene; Chemical: biotin
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: graphene; Chemical: biotin