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Moreover , TSS - SPIONs were investigated regarding to their iron core size , hydrodynamic diameter , zeta potential , iron contents , molar relaxivities ( r1 and r2 ) , and cellular internalization .
 Chemical: iron; Chemical: iron
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: iron; Chemical: iron