Development of metal enhanced fluorescent nanomaterials featuring gold nanocubes in proximity to carbon nanodots

Abstract

In the present study, gold nanocube (AuNC) particles conjugated with a carbon nanodot (CND) layer and spaced with polyethylene glycol (PEG) were prepared to generate a metal-enhanced fluorescence (MEF) effect. This is the first report of MEF from gold nanoparticles in proximity to CNDs. Biocompatible materials (AuNCs, CNDs, and PEGs) were used to fabricate the proposed AuNC-CND complex, thus providing potential utilities of fluorescent materials in various nanobiotechnology fields. Additionally, the use of AuNCs played a critical role in controlling the size and shape of amorphous CNDs exhibiting a soft polymer cluster morphology stemming from bottom-up synthesis. We also attempted to explain the complex interplay between the quenching and enhancing processes through the energy transfer direction between the AuNCs and CNDs based on our experimental results for photoluminescence emission spectra, dark-field microscope imaging, and single-particle scattering measurements in relation to differences in the size of core metals, and the concentration of fluorophores.