3649
Antigen - specific activation of cytotoxic T cells can be enhanced up to three - fold more than soluble controls when using functionalized bundled carbon nanotube substrates ( ( b ) CNTs ) .
 Chemical: carbon
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: carbon