7509
Fourteen individual SERS nanoantennas , Au nanoparticle aggregates ranging from dimers to undecamers , coated in a reporter molecule and encased in a protective silica shell , were excited using eight laser wavelengths .
 Au, silica
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Chemical 
Text: {0} 
Answer:
 Au, silica