Silver nanoparticles modified HLNPs were synthesized using silver ammonia solution (Tollens' reagent)) as precursor. 10 mg of silver nitrate (AgNO3) was dissolved in 3 ml of deionized water and 40 µL of aqueous ammonia solution was added and stirred to dissolve all the brown precipitate formed. Then 1 ml of HLNP dispersion (10 mg/mL, concentrated using centrifugation) was added dropwise to the stirring silver ammonia solution and was further stirred for 2 h. After formation of metallic silver, samples were purified by repeated steps of centrifugation and redispersion in deionized water.