Graphene Oxide Nanocarrier Research Articles

PEGylated graphene oxide as a nanocarrier for podophyllotoxin

Graphene, a two-dimensional nanomaterial, has become a hot spot of research at the interface of nanotechnology and biomedicine. In this study, the oxidized form of graphene, graphene oxide (GO), was functionalized with 6-armed polyethylene glycol (PEG), which rendered it stable and biocompatible in physiological solution. The successful synthesis of PEGylated graphene oxide (GO-PEG) nanocarrier with low toxicity was confirmed by UV–Vis spectroscopy, Fourier-transform infrared spectroscopy, atomic force microscopy, and thermogravimetric analysis. By dynamic light scattering (DLS), the size distribution of the nanoparticles were shown to be 60–200 nm. Furthermore, a complex by loading an aromatic anticancer compound, podophyllotoxin (PPT), onto GO-PEG (GO-PEG/PPT) via π–π stacking and hydrophobic interactions was investigated. It was demonstrated that GO-PEG/PPT showed remarkably high cytotoxicity compared to free PPT in both the human cervical adenocarcinoma HeLa cell line and human hepatoma SMMC-7721 cell line. The loading and delivery of anticancer drugs using this kind of graphene-based nanocarrier may find potential application in biomedicine.

Functional two-dimensional nanoarchitectures based on chemically converted graphene oxide and hematoporphyrin under the sulfuric acid treatment

Abstract A model photosensitizer, hematoporphyrin (HP), captured by graphene oxide (GO) nanocarrier with and without the treatment by sulfuric acid was investigated for UV–VIS absorption, luminescence properties and Raman scattering. We demonstrate that combination of optical techniques can be efficiently used to detect an interfacial structure of hematoporphyrine/graphene oxide (HP/GO) nanoensembles. Finally, stable in aqueous media at neutral pH HP/GO nanocomposite were obtained as a result of esterification reaction catalyzed by sulfuric acid. The nanocomposite with stronger absorption and emission represents a layered structure composed of hematoporphyrine oligomers adsorbed on the surface of GO in monolayer through electrostatic and π-stacking interactions. The formation of such hybrid structures, where graphene oxide plays a role of a non-toxic sheet-like nanocarrier, open the way to create a functional nanocomposites with a high level of selective emission and efficient photosensitizing ability utilizing unique graphene properties as singlet oxygen generation enhancer.

Poly(acrylic acid)-Grafted Graphene Oxide as an Intracellular Protein Carrier

A pH-sensitive poly(acrylic acid)-grafted graphene oxide (GO-PAA) nanocarrier was synthesized by in situ atom transfer radical polymerization to allow the oral delivery of hydrophilic macromolecular proteins in their active forms to specific cells or organs. The synthesis, morphology, and physiochemical properties of GO-PAA were examined. A model protein, bovine serum albumin (BSA) labeled with fluorescein isothiocyanate (FITC) (BSAFITC), was loaded onto GO-PAA through noncovalent interactions and its release was arrested at acidic pH similar to stomach, whereas at pH similar to intestine it was reduced, which paves way for site specific delivery without its degradation in the gastrointestinal tract. Confocal laser microscopy showed that the BSAFITC-loaded GO-PAA was internalized by KB cells by endocytosis and released into cytoplasm. Thus the GO-PAA as a transmembrane transporter is a new class of drug transporters with potential protein delivery applications.