Hemocompatibility and Macrophage Response of Pristine and Functionalized Graphene

Abstract

Graphene and its derivatives are being proposed for several important biomedical applications including drug delivery, gene delivery, contrast imaging, and anticancer therapy. Most of these applications demand intravenous injection of graphene and hence evaluation of its hemocompatibility is an essential prerequisite. Herein, both pristine and functionalized graphene are extensively characterized for their interactions with murine macrophage RAW 264.7 cells and human primary blood components. Detailed analyses of the potential uptake by macrophages, effects on its metabolic activity, membrane integrity, induction of reactive oxygen stress, hemolysis, platelet activation, platelet aggregation, coagulation cascade, cytokine induction, immune cell activation, and immune cell suppression are performed using optimized protocols for nanotoxicity evaluation. Electron microscopy, confocal Raman spectral mapping, and confocal fluorescence imaging studies show active interaction of both the graphene systems with macrophage cells, and the reactive oxygen species mediated toxicity effects of hydrophobic pristine samples are significantly reduced by surface functionalization. In the case of hemocompatibility, both types of graphene show excellent compatibility with red blood cells, platelets, and plasma coagulation pathways, and minimal alteration in the cytokine expression by human peripheral blood mononuclear cells. Further, both samples do not cause any premature immune cell activation or suppression up to a relatively high concentration of 75 μg mL(-1) after 72 h of incubation under in vitro conditions. This study clearly suggests that the observed toxicity effects of pristine graphene towards macrophage cells can be easily averted by surface functionalization and both the systems show excellent hemocompatibility.

Thermally Reduced Graphene Oxide Nanohybrids of Chiral Functional Naphthalenediimides for Prostate Cancer Cells Bioimaging

“…[ 31 ] These optical properties combined with biocompatibility have rendered them ideal candidates for further functionalization and exploitation for fl uorescent bioimaging. [ 30,31,33 ] The assembly process between NDIs and nanomaterials such as C 60 , C 70 , and SWNTs has been explored, by us and others. [ 33,[35][36][37] Recently, an interest in understanding their interactions with planar carbon system (denoted here PCS) has emerged and these are believed to be based on noncovalent contacts such as π-stacking coupled with hydrophobic interactions and Coulombic attractions of the electron deficient NDI core to the electron rich surface of graphene and its derivatives.…”

“…[ 67 ] Although the mechanisms for their toxicity toward cells are not completely understood as they follow different paths, [ 68 ] the formation of reactive oxygen species seems to be the most recurring mechanism observed. [ 69,70 ] While pristine carbon based materials tend to accumulate in physiological solution due to electrostatic interactions and nonspecifi c bindings to proteins, [ 71 ] surface-modifi ed graphene-like materials are often deemed to be less toxic. [ 70,72 ] Our results are consistent with these observations.…”

“…[ 69,70 ] While pristine carbon based materials tend to accumulate in physiological solution due to electrostatic interactions and nonspecifi c bindings to proteins, [ 71 ] surface-modifi ed graphene-like materials are often deemed to be less toxic. [ 70,72 ] Our results are consistent with these observations. These results demonstrate that the functionalization of coronene and TRGO with D -phenylalanine NDIs considerably improves the in vitro biocompatibility of the pristine PCSs presented in this work.…”

Synthesis, toxicity, biocompatibility, and biomedical applications of graphene and graphene-related materials

“…RAW 264.7 macrophages treated with pristine graphene were found to show increased ROS generation and impairment of mitochondrial membrane potential and cell death by inducing MAP kinases and transforming growth factor-beta-related signaling pathways. 172,173 Recently, we found that resveratrol-reduced GO induced more toxic effects than GO in human ovarian cancer cells by increasing LDH release, ROS generation, activation of caspase-3, and DNA fragmentation. 113 For example, GO reduced by Typha angustifolia leaf extract induced apoptosis by causing morphological changes (Figure 2).…”

Current applications of graphene oxide in nanomedicine

“…Initial studies examining the hemocompatibility of graphene and GO showed that graphene exerted a slightly higher cytotoxic effect than GO due to its strong hydrophobic interaction with cell membranes with both materials exerting insignificant hemolytic effect (up to 75 µg/ mL). 167 In contrast, Liao et al 168 demonstrated that submicronsized GO sheets induced the greatest hemolytic activity, whereas aggregated graphene sheets exhibited the lowest hemolytic activity. Coating the oxidized sheets with chitosan almost eliminated hemolytic activity.…”