This study aimed to demonstrate that curcumin (Cur)-containing graphene composites have high anticancer activity. Specifically, graphene-derivatives were used as nanovectors for the delivery of the hydrophobic anticancer drug Cur based on pH dependence. Different Cur-graphene composites were prepared based on polar interactions between Cur and the number of oxygen-containing functional groups of respective starting materials. The degree of drug-loading was found to be increased by increasing the number of oxygen-containing functional groups in graphene-derivatives. We demonstrated a synergistic effect of Cur-graphene composites on cancer cell death (HCT 116) both in vitro and in vivo. As-prepared graphene quantum dot (GQD)-Cur composites contained the highest amount of Cur nano-particles and exhibited the best anticancer activity compared to the other composites including Cur alone at the same dose. This is the first example of synergistic chemotherapy using GQD-Cur composites simultaneous with superficial bioprobes for tumor imaging.

One of the most efficient and straightforward methods for production of graphene quantum dots (GQDs) could be their direct preparation from graphite powder by one-pot synthesis using high-powered microwave irradiation. It is believed that in this way, graphite can be multiply broken by repeated redox reactions, which leads to a high yield and mass production.

To prepare carbon-based fluorescent materials such as graphene quantum dots (GQDs), new and effective methods are needed to convert one-dimensional (1D) or two-dimensional (2D) carbon materials to 0D GQDs. Here, we report a novel acid-free and oxone oxidant-assisted solvothermal synthesis of GQDs using various natural carbon resources including graphite (G), multiwall carbon nanotubes (M), carbon fibers (CF), and charcoal (C). This acid-free method, not requiring the neutralization process of strong acids, exhibits a simple and eco-friendly purification process and also represents a recycling production process, together with mass production and high yield. Newly synthesized GQDs exhibited a strong blue photoluminescence (PL) under 365 nm UV light illumination. The PL emission peaks of all the recycled GQDs did not change.

The emergence of stretchable devices that combine with conductive properties offers new exciting opportunities for wearable applications. Here, a novel, convenient and inexpensive solution process was demonstrated to prepare in situ silver (Ag) or platinum (Pt) nanoparticles (NPs)-embedded rGO hybrid materials using formic acid duality in the presence of AgNO3 or H2PtCl6 at low temperature. The reduction duality of the formic acid can convert graphene oxide (GO) to rGO and simultaneously deposit the positively charged metal ion to metal NP on rGO while the formic acid itself is converted to a CO2 evolving gas that is eco-friendly. The AgNP-embedded rGO hybrid electrode on an elastomeric substrate exhibited superior stretchable properties including a maximum conductivity of 3012 S cm-1 (at 0 % strain) and 322.8 S cm-1 (at 35 % strain). Its fabrication process using a printing method is scalable. Surprisingly, the electrode can survive even in continuous stretching cycles.