Cyto-toxicity, biocompatibility and cellular response of carbon dots-plasmonic based nano-hybrids for bioimaging

In this study, hybrid carbon dots-plasmonic nanostructures including carbon dots/polyethyleneimine/gold (C-dots/PEI/Au), and carbon dots/polyethyleneimine/silver (C-dots/PEI/Ag) have been prepared using a microwave irradiation method. The prepared hybrid nanostructures have been characterized via optical spectroscopy, high resolution transmission electron microscopy (HRTEM), and X-ray diffraction (XRD). A remarkable enhancement in the optical parameters, such as absorptivity and quantum yield (QY), has been observed for the hybrid nanostructure compared to pure carbon dots. This plasmonic enhancement was more pronounced in the presence of silver (C-dots/PEI/Ag nanohybrid) than that of gold (C-dots/PEI/Au nanohybrid). This is referred to the low intrinsic loss and the degree of the overlap between the absorption spectra of silver nanoparticles and carbon dots. Furthermore, the biocompatibility assay and cellular response on epithelial kidney (Vero) normal cell has been investigated. The results showed that the optimal dose of treatment is about similar to 200 mu g ml(-1) using both C-dots/PEI/Au or C-dots/PEI/Ag, nano-hybrids could be used safely in diagnostic bioimaging applications.