Preparation of hybrid fluorescent nanocomposites with enhanced fluorescence and their application

Abstract In this study, a kind of core–shell structured fluorescent nanocomposites was synthesized by self-assembly technique. To prepare these hybrid nanocomposites, multi-branched gold nanoparticles (MBG NPs) were employed as the core. And SiO 2 shells were coated on the MBG NPs to facilitate further modification. Polyelectrolyte (PE) multilayer composed of poly( l -lysine) (PLL) and poly(acrylic acid) (PAA) was further coated onto the MBG@SiO 2 nanocomposites to sever as the thickness controllable layer. Then positively charged porphyrin derivative 5,10,15,20-tetrakis(1-methyl-4-pyridinio) porphyrin tetra( p -toluenesulfonate) (Por 4+ ) was adsorbed on the prepared MBG@SiO 2 /PE nanocomposites as the fluorophore. The fluorescence intensity of Por 4+ was enhanced by 2.4-fold when three PLL/PAA bilayers were used as the PE multilayer. Meanwhile, the singlet oxygen generation property of Por 4+ has been accelerated at the presence of the prepared nanocomposites. And the nanocomposites show potential usage in efficient antibacterial experiment.