25556
Briefly , nanogels were prepared by the electrostatic interaction of negatively charged alginate sodium with branched PEI2k , followed by disulfide cross - linking to generate bioreducible nanogels ( AP - SS ) .
 Chemical: sodium; Chemical: disulfide
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: sodium; Chemical: disulfide