Facile Synthesis of Water-Soluble, Highly-Fluorescent Graphene Quantum Dots from Graphene Oxide Reduction for Efficient Cell Labelling

Minati Minati,Del Piano Del Piano

doi:10.3390/c5040077

Abstract

In this work, we report a simple, one-step, green procedure to fabricate strong blue and yellow photoluminescent graphene quantum dots (GQDs) as by-product of the synthesis of mesoporous graphene hydrogel (GHs). The graphene hydrogel was obtained by chemical reduction of graphene oxide using ascorbic acid at mild temperature. As a consequence of the network formation, small fluorescent GQDs can be isolated from the residual solvent, purified from the by-products and finally concentrated to produce GQDs. The GQDs chemistry and morphology were characterized by X-ray Photoelectron Spectroscopy (XPS) and Transmission Electron Microscopy (TEM). The GQDs mean diameter was about 5–10 nm and they exhibited an intense luminescence in the visible range with an excitation wavelength-dependent fluorescence. Our experiments showed that GQDs were easily internalized in living cells and furthermore, such internalization did not adversely affect cell viability.

Highlights

The optical properties of carbon nanostructures have attracted great interest from the scientific community in the last years [1,2,3,4,5,6,7]
In this work, we report a simple, one-step, green procedure to fabricate strong blue and yellow photoluminescent graphene quantum dots (GQDs) as by-product of the synthesis of mesoporous graphene hydrogel (GHs)
The chemical reduction of graphene oxide by ascorbic acid in the absence of mechanical agitation causes the formation of a graphene hydrogel derived from the assembly of graphene oxide induced by π–π stacking between individual sheets [20]

Summary

Introduction

The optical properties of carbon nanostructures have attracted great interest from the scientific community in the last years [1,2,3,4,5,6,7]. From the first paper presented by Riggs [10] different synthesis techniques have been developed to obtain carbon nanostructures with outstanding optical activity. These include bottom-up approaches such as chemical reduction of carbon compounds as well as top-down methods, such as laser ablation and solvothermal carbonization [11,12,13,14]. These systems are not affected by photobleaching as the organic dyes.

Methods

Results

Conclusion