29685
A series of dual stimuli responsive synthetic polymer bioconjugate chimeric materials , poly ( N - isopropylacrylamide ) 55 - block - poly ( l - histidine ) n [ p ( NIPAM ) 55 - b - p ( His ) n ] ( n = 50 , 75 , 100 , 125 ) , have been synthesized by employing reversible addition - fragmentation chain transfer polymerization of NIPAM , followed by ring - opening polymerization of alpha - amino acid N - carboxyanhydrides .
 poly ( N - isopropylacrylamide ) 55 - block - poly ( l - histidine ) n, p ( NIPAM ) 55 - b - p ( His ) n, NIPAM, alpha - amino acid N - carboxyanhydrides
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Chemical 
Text: {0} 
Answer:
 poly ( N - isopropylacrylamide ) 55 - block - poly ( l - histidine ) n, p ( NIPAM ) 55 - b - p ( His ) n, NIPAM, alpha - amino acid N - carboxyanhydrides