Current applications of graphene oxide in nanomedicine

Abstract

Graphene has attracted the attention of the entire scientific community due to its unique mechanical and electrochemical, electronic, biomaterial, and chemical properties. The water-soluble derivative of graphene, graphene oxide, is highly prized and continues to be intensely investigated by scientists around the world. This review seeks to provide an overview of the currents applications of graphene oxide in nanomedicine, focusing on delivery systems, tissue engineering, cancer therapies, imaging, and cytotoxicity, together with a short discussion on the difficulties and the trends for future research regarding this amazing material.

Keywords: antibacterial; biofunctionalization; cancer; contrast agent; cytotoxicity; diagnostics; green; imaging; therapy.

Figure 1

Schematic illustration of the preparation, ideal structural transformation, drug loading, and reduction-triggered release of the cysteine polymethacrylic acid cross-linked nano graphene oxide polyethylene glycol carriers. Reproduced with permission from Zhao X, Yang L, Li X, et al. Functionalized graphene oxide nanoparticles for cancer cell specific delivery of antitumor drug. Bioconjug Chem. 2015;26(1):128–136. Copyright © 2015 American Chemical Society. Abbreviations: PEG, polyethylene glycol; GSH, glutathione; DOX, doxorubicin; CPMAA, cysteine polymethacrylic acid; PMAA, polymethacrylic acid.

Figure 2

Fabrication of polyethylenimine poly(sodium 4-styrenesulfonate) graphene oxide delivery vehicle and MDR reversion. Reproduced from Zhi F, Dong H, Jia X, et al. Functionalized graphene oxide mediated adriamycin delivery and miR-21 gene silencing to overcome tumor multidrug resistance in vitro. Plos One. 2013;8(3):e60034. Abbreviations: GO, graphene oxide; PLL, poly-l-lysine; PSS, poly(sodium 4-styrenesulfonate); PEI, polyethylenimine; PPG, poly(sodium 4-styrenesulfonate) (PSS)/GO; ADR, Adriamycin.

Figure 3

(A) Confocal cross-sectional images of the control group (top) and the 3L tissue constructs (bottom) after 2 days of culture. F-actin and cell nuclei were labeled with green and blue fluorescent dyes, respectively. The 3T3 fibroblasts were found to connect the cells on the first layer to the cells on the second layer through noncontinuous PLL-coated GO layer (red arrow, empty black area). (B) Hematoxylin and eosin (H&E) stain images of 3L 3T3 fibroblasts. The solid red lines indicate the interfaces between each layer. (C) Schematic illustration of the cross-section of the 2L construct showing the cells residing above and below the PLL-coated GO nanofilms. (D) SEM images showing the cross-section and (E) the thickness of 2L constructs fabricated with various concentrations of PLL-coated GOs as interlayer GO films. (F) SEM images showing the cross-section, and (G) the thickness of 1L, 2L, and 3L constructs. The thickness of the constructs was estimated from the corresponding SEM images. Reproduced from Shin SR, Aghaei-Ghareh-Bolagh B, Gao X, et al. Layer-by-layer assembly of 3D tissue constructs with functionalized graphene. Adv Mater. 2014;22(39):6136–6144. Copyright © 2015 Wiley ACH. Abbreviations: GO, graphene oxide; PLL, poly-L-lysine; SEM, scanning electron microscope.

Figure 4

Neuronal differentiation of hADMSCs using NGO grid-patterned substrate. Notes: (A) Images of neural-induced hADMSCs grown on poly-L-lysine-coated Au (Au), NGO-coated Au (Au-NGO), and NGO grid-patterned substrates (Au-NGO (Grid)). All substrates were coated with laminin to facilitate cell attachment. Cellular growth and morphology were monitored over 15 days, followed by staining for the neuronal marker TuJ1 (red) and nucleus (blue). Scale bars =20 µm. (B) Phase-contrast and fluorescence images of cells stained for F-actin (green) and nucleus (blue) after 15 days of cultivation show extensive cellular extension on NGO-grid patterns. Scale bar =50 µm. (C) Quantitative comparison of the length of cellular extension on various substrates (n=3; *P<0.01, Student’s unpaired t-test). (D) Quantitative comparison of the percentage of cell expressing the neuronal marker TuJ1 on various substrates (n=3; *P<0.01, Student’s unpaired t-test). Reproduced with permission from Kim TK, Shah S, Yang L. Controlling differentiation of adipose-derived stem cells using combinatorial graphene hybrid-pattern arrays. ACS Nano. 2015:9(4):3780–3790. Copyright ©2015 American Chemical Society. Abbreviations: NGO, nano graphene oxide; TuJ1, class III beta-tubulin.

Figure 5

A schematic diagram of magnetic resonance (MR)/computed tomography (CT) imaging and near infrared photothermal therapy (PTT) using the graphene oxide/BaGdF₅/polyethylene glycol (PEG) nanocomposites. Reproduced with permission from Zhang H, Wu H, Wang J, et al. Graphene oxide-BaGdF5 nanocomposites for multi-modal imaging and photothermal therapy. Biomaterials. 2015;42:66–77. Copyright © 2015 Elsevier.

Figure 6

Schematic diagram showing proposed toxic mechanisms of GO on T lymphocytes based on the current data. From left to right are p-GO, GO-COOH, and GO-PEI, respectively. Dotted line indicates signal pathway, and full line indicates the way of GO-PEI transport. Reproduced with permission from Ding Z, Zhang Z, Ma H, Chen Y. In vitro hemocompatibility and toxic mechanism of graphene oxide on human peripheral blood T lymphocytes and serum albumin. ACS Appl Mater Interfaces. 2014;6(22):19797–19807. Copyright ©2015 American Chemical Society. Abbreviations: Bcl-2, B-cell lymphoma-2; PEI, polyethylenimine; p-GO, pristine graphene oxide; ROS, reactive oxygen species.

Figure 7

Physiological monitoring of C2C12 myoblasts by impedance/temperature sensors and in vitro tests of the efficacy of ROS scavenging nanoparticles. Notes: (A) Impedance and temperature sensors integrated on a PDMS substrate. (B) Calibration curve of temperature sensor: normalized resistance (% R change) as a function of temperature. The red arrow indicates the temperature of the growth medium during the culture. (C) Electrical characterization of the impedance sensor in the growth medium at 37°C. Impedance curve measured from 1 Hz to 1 MHz with a bias voltage of 0.01 V. The inset shows the magnified view of the red-dotted region. Repeated measurements show minor deviations. (D) Current-voltage (I–V) curve, whose slope indicates the conductance. The inset shows the magnified view. Repeated measurements confirm the stability of the sensor. (E and F) The impedance curve changed as (E) the proliferation and (F) the differentiation proceeded. (G) Impedance value measured at 17.7 kHz as the culture proceeded. Red and blue curves show the cells in growth and differentiation media, respectively. The control (black) used human dermal fibroblasts. (H) Conductance values calculated from IV curves with a range from −0.1 to +0.1 V. (I) Schematic illustration and TEM image (background image) of ROS-scavenging ceria nanoparticles. The ceria NPs are functionalized by oleylamine and methoxy-polyethylene glycol. (J and K) Fluorescence image of C2C12 myoblasts (stained with calcein AM) after 30 minutes of H₂O₂/Ceria NP treatment (J) and relative viability plot from fluorescence images (K). (L) Plots of impedance as a function of time in different treatment groups. Reproduced with permission from Kim SJ, Cho HR, Cho KW, et al. Multifunctional cell-culture platform for aligned cell sheet monitoring, transfer printing, and therapy. ACS Nano. 2015;9(3):2677–2688. Copyright ©2015 American Chemical Society. Abbreviations: ROS, reactive oxygen species; NP, nanoparticle; TEM, transmission electron microscope; PDMS, polydimethylsiloxane.