Fabrication of Luminol and Lucigenin Bifunctionalized Gold Nnanoparticles/Graphene Oxide Nanocomposites with Dual-Wavelength Chemiluminescence

A facile, fast, and reliable method was proposed to prepare luminol and lucigenin bifunctionalized AuNPs/GO nanocomposites via absorption of AuCl₄^– by positively charged lucigenin functionalized GO and the subsequent reduction of AuCl₄^– by luminol at room temperature for the first time. The morphology and surface composition of the nanocomposites were characterized by transmission electron microscopy, X-ray powder diffraction, and mass and fluorescence spectra. The results indicated that AuNPs with a uniform size are fairly well monodispersed on the surface of GO. The size of AuNPs in the nanocomposites was tunable from 8 to 18 nm by changing the amount of AuCl₄^–. Moreover, it was found that luminol and lucigenin coexisted on the surface of the nanocomposites. A formation mechanism of AuNPs/GO nanocomposites is proposed. It is suggested that lucigenin molecules and AuNPs were located at the surface of GO by π–π stacking and electrostatic force respectively, and luminol existed on the surface of AuNPs by virtue of Au–N covalent interaction in the as-prepared nanocomposites. Because luminol and lucigenin were attached to the surface of the nanocomposites, the obtained nanocomposites could react with hydrogen peroxide resulting in a good dual-wavelength chemiluminescence activity. Also, the nanocomposites could also react with silver nitrate giving rise to chemiluminescence emission. Besides, the nanocomposites exhibited fluorescence properties. The nanocomposites could be considered as not only functionalized materials but also as a promising platform for multipurpose sensing and bioassays.