Approaches, Derivatives and Applications Vasilios Georgakilas,† Michal Otyepka,‡ Athanasios B. Bourlinos,‡ Vimlesh Chandra, Namdong Kim, K. Christian Kemp, Pavel Hobza,‡,§,⊥ Radek Zboril,*,‡ and Kwang S. Kim* †Institute of Materials Science, NCSR “Demokritos”, Ag. Paraskevi Attikis, 15310 Athens, Greece ‡Regional Centre of Advanced Technologies and Materials, Department of Physical Chemistry, Faculty of Science, Palacky University Olomouc, 17. listopadu 12, 771 46 Olomouc, Czech Republic Center for Superfunctional Materials, Department of Chemistry, Pohang University of Science and Technology, San 31, Hyojadong, Namgu, Pohang 790-784, Korea Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, v.v.i., Flemingovo naḿ. 2, 166 10 Prague 6, Czech Republic

Functionalization of Graphene: Covalent and Non-Covalent Approaches, Derivatives and Applications

Graphene has attracted tremendous research interest in recent years, owing to its exceptional properties. The scaled-up and reliable production of graphene derivatives, such as graphene oxide (GO) and reduced graphene oxide (rGO), offers a wide range of possibilities to synthesize graphene-based functional materials for various applications. This critical review presents and discusses the current development of graphene-based composites. After introduction of the synthesis methods for graphene and its derivatives as well as their properties, we focus on the description of various methods to synthesize graphene-based composites, especially those with functional polymers and inorganic nanostructures. Particular emphasis is placed on strategies for the optimization of composite properties. Lastly, the advantages of graphene-based composites in applications such as the Li-ion batteries, supercapacitors, fuel cells, photovoltaic devices, photocatalysis, as well as Raman enhancement are described (279 references).

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Graphene-based composites

Graphene based materials: Past, present and future

Graphene, a two-dimensional, single-layer sheet of sp(2) hybridized carbon atoms, has attracted tremendous attention and research interest, owing to its exceptional physical properties, such as high electronic conductivity, good thermal stability, and excellent mechanical strength. Other forms of graphene-related materials, including graphene oxide, reduced graphene oxide, and exfoliated graphite, have been reliably produced in large scale. The promising properties together with the ease of processibility and functionalization make graphene-based materials ideal candidates for incorporation into a variety of functional materials. Importantly, graphene and its derivatives have been explored in a wide range of applications, such as electronic and photonic devices, clean energy, and sensors. In this review, after a general introduction to graphene and its derivatives, the synthesis, characterization, properties, and applications of graphene-based materials are discussed.

Graphene-Based Materials: Synthesis, Characterization, Properties, and Applications

Functional Nanomaterials for Phototherapies of Cancer

A superparamagnetic graphene oxide –Fe3O4nanoparticles hybrid (GO–Fe3O4) was prepared via a simple and effective chemical precipitation method. The amount of loading of Fe3O4 on GO was estimated as 18.6 wt% by atomic absorption spectrometry. The hybrid was then loaded with doxorubicin hydrochloride (DXR) and the loading capacity was as high as 1.08 mg mg−1. Both of the GO–Fe3O4 hybrids before and after loading with DXR can be dispersed well in aqueous solution. They can congregate under acidic conditions and move regularly under the force of an external magnet. Furthermore, the aggregated hybrid can be redispersed to form a stable suspension under basic conditions. These properties make it a potential candidate for controlled targeted drug delivery and release.

Superparamagnetic graphene oxide–Fe3O4nanoparticles hybrid for controlled targeted drug carriers

A dual-targeting drug delivery and pH-sensitive controlled release system based on multi-functionalized graphene oxide (GO) was established in order to enhance the effect of targeted drug delivery and realize intelligently controlled release. A superparamagnetic GO–Fe3O4 nanohybrid was firstly prepared via a simple and effective chemical precipitation method. Then folic acid, a targeting agent toward some tumor cells, was conjugated onto Fe3O4 nanoparticlesvia the chemical linkage with amino groups of the 3-aminopropyl triethoxysilane (APS) modified superparamagnetic GO–Fe3O4 nanohybrid, to give the multi-functionalized GO. Doxorubicin hydrochloride (Dox) as an anti-tumor drug model was loaded onto the surface of this multi-functionalized GO via π–π stacking. The drug loading capacity of this multi-functionalized GO is as high as 0.387 mg mg−1 and the drug release depends strongly on pH values. Cell uptake studies were carried out using fluorescein isothiocyanate labeled or Dox loaded multi-functionalized GO to evaluate their targeted delivery property and toxicity to tumor cells. The results show that this multi-functionalized GO has potential applications for targeted delivery and the controlled release of anticancer drugs.

Multi-functionalized graphene oxide based anticancer drug-carrier with dual-targeting function and pH-sensitivity

Functionalized graphene oxide (GO) with folic acid-conjugated chitosan oligosaccharide (FACO) containing quaternary ammonium groups (GO-FACO+) was successfully prepared. The formation and composition of GO-FACO+ were confirmed by FTIR, UV–Vis, AFM, TGA, and zeta-potential. Cell experiments show that cellular uptake of fluorescein FAM-labeled DNA sequence (FAM-DNA) delivered by GO-FACO+ exhibits higher efficiency in doxorubicin chloride (Dox)-resistant MCF-7 human breast cancer cells (MCF-7/Dox) with folate receptor overexpressed than that delivered by chitosan oligosaccharide (CO)-functionalized graphene oxides (GO-CO+) without folic acid modification and in human lung cancer A549 cells with folate receptor negatively expressed. The loading efficiency of Dox on GO-FACO+ was 568.4 μg mg−1 at the initial Dox concentration of 0.5 mg mL−1, and in vitro release of Dox showed strong pH dependence. MDR1 siRNA transfected by GO-FACO+ could efficiently knockdown the MDR1 mRNA and P-gp expression levels in MCF-7/Dox cells. GO-FACO+ shows no obvious toxicity even at 500 μg mL−1. The sequential deliveries of MDR1 siRNA and Dox by GO-FACO+ exhibited much higher cytotoxicity against MCF-7/Dox cells than only delivery of Dox by GO-FACO+ when Dox concentration is lower than 25 μg mL−1, while excess 80 % cells were killed in the two cases when Dox concentration is higher than 30 μg mL−1. Taken together, this functionalized GO has potential applications for targeted intracellular delivery of anti-tumor drugs and genes.

Folic acid-conjugated graphene oxide as a transporter of chemotherapeutic drug and siRNA for reversal of cancer drug resistance

The invention relates to a common carrier material based on graphene oxide for a targeting anticancer drug and a gene and application and application Folic acid, lactobionic acid and other tumor cell targeting or liver targeting molecules and part of amino groups of soluble chitosan are connected by amide bonds to prepare a conjugate, the conjugate is then connected with graphene oxide, quaternization is performed by using an epoxy compound with a quaternary ammonium group, and gene molecules are loaded by the quaternizationquaternized part of the chitosan through electrostatic attraction; and then the anticancer drug is loaded by pi-pi conjugates, hydrogen bonds and hydrophobic effects in a non-covalent bond method By adopting the targeting performance of targeting molecules and effects of graphene oxide of a particular size to enhance penetration and retention in tumor tissues and combining the performance of the graphene oxide for pH response control release of the loaded drug, the drug can be realized released in a tumor cell, an intelligent delivery system for the common carrier of the tumor targeting or liver targeting anticancer drug and the gene is synthesized from the perspective of synergetic medication, and a theoretical basis and a method basis are provided for combined therapy of tumor

Yinsong Wang

Papers

Superparamagnetic graphene oxide–Fe3O4nanoparticles hybrid for controlled targeted drug carriers

Multi-functionalized graphene oxide based anticancer drug-carrier with dual-targeting function and pH-sensitivity

Folic acid-conjugated graphene oxide as a transporter of chemotherapeutic drug and siRNA for reversal of cancer drug resistance

Common carrier material for targeting anticancer drug and gene and preparation and application

Graphene oxide-based target gene vector material and preparation and use thereof