Metal-Enhanced Fluorescent Carbon Quantum Dots via One-Pot Solid State Synthesis for Cell Imaging

Abstract

In this study, a facile one-pot solid-state synthesis method is developed to shed light on the metal-enhanced fluorescence (MEF) effect in carbon quantum dots (CQDs) and gold nanoparticles (AuNPs) hybrid materials. This is one of the few studies on the solid-state synthesis of N-doped CQDs/gold hybrid nanomaterials. We have conducted various sets of experiments to reveal the role of individual reagents during the nucleation and growth of nanoparticles. We have demonstrated that the addition of a small amount of gold salt illustrates a paramount effect (10 3 -fold) in photoluminescence intensity. This effect is ascribed to MEF, which is caused due to interactions between the excited-state fluorophores and the free surface electrons of metal nanoparticles. It is interesting to note that a further increase of gold yields fluorescence quenching due to a large number of formed AuNPs causing fluorescence resonance energy transfer. By adjusting the volume ratio of gold salt and CD precursors, it is possible to obtain the CQDs−AuNPs hybrid with the highest fluorescence, which produces extensive visible light under 460 nm excitation. Synthesized materials have been successfully used for imaging human dermal fibroblasts and A549 lung epithelial cells. The dose-dependent cytotoxicity studies reveal that the hybrid structures do not have cytotoxicity.

Carbon Dots—Types, Obtaining and Application in Biotechnology and Food Technology

“…It therefore follows that by properly selecting the synthesis parameters, it is possible to control which cellular elements will undergo staining. For example, carbon dots obtained by the microwave method will accumulate mainly in the cell membrane and close to the cell nucleus [59,65,70]. There is also a lot of research currently underway on the use of carbon quantum dots in monitoring environmental pH.…”

Integration of N, P-doped carbon quantum dots with hydrogel as a solid-phase fluorescent probe for adsorption and detection of Fe3+

“…Carbon quantum dots (CQDs), as one the typical fluorescent carbon nanomaterials, have captured many interesting in the research field of fluorescence sensors due to its incomparable advantages such as photostability, bio-compatibility and low cytotoxicity, etc [19,20]. Apart from the organic molecules and carbon materials as the feedstocks, CQDs can also be derived from a variety of biomass materials, which shows not only low cost but also environmentally friendly [21][22][23][24].…”