15483
Moreover , the PEI - betaine conjugates display satisfactory DNA condensation capability ; and in the absence and presence of serum , PEI - DMAAPS23 % / pEGFP and PEI - DMAAPS55 % / pEGFP complexes exhibited remarkable gene transfection efficiencies determined by flow cytometry , which are in general several times higher than that of PEI 25K .
 Chemical: PEI; Chemical: PEI; Chemical: DMAAPS23; Chemical: PEI; Chemical: DMAAPS55; Chemical: PEI
Given options, please tell me the categories of all the listed entity words.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
 Entities: PEI, PEI, DMAAPS23, PEI, DMAAPS55, PEI 
Answer:
 Chemical: PEI; Chemical: PEI; Chemical: DMAAPS23; Chemical: PEI; Chemical: DMAAPS55; Chemical: PEI