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Immune-camouflaged graphene oxide nanosheets for negative regulation of phagocytosis by macrophages

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Abstract

Signal regulatory protein alpha (SIRPα) is highly expressed in macrophages of the reticuloendothelial system and in tumor-associated macrophages, whereas tumor cells express the surface membrane protein, CD47, which interacts with SIRPα to negatively regulate phagocytosis. In this study, we modified the surfaces of graphene oxide (GO) nanosheets with a CD47-like SIRPα-binding peptide (SP). The presence of SP on GO nanosheets reduced the macrophage uptake to a greater extent than the PEGylation of such nanosheets. This reduced uptake was found to be mediated by the activation of Src homology region 2 domain-containing phosphatase 1 (SHP-1) and the downstream inhibition of myosin assembly, which is necessary for phagosome formation. Unlike SP-coated GO nanosheets, PEGylated GO nanosheets did not affect myosin assembly or phagocytosis. After in vivo systemic administration, the clearance of SP-coated GO nanosheets was slower than that of PEGylated GO nanosheets, and this difference increased with repeated administration. Finally, SP-coated GO nanosheets showed a higher distribution to tumor tissues than PEGylated GO nanosheets or a physical mixture of SP and GO nanosheets. Our findings indicate that immune-camouflaged GO nanosheets with natural CD47-like SIRPα-binding molecules can reduce the nonspecific loss of such nanosheets through macrophage uptake, thereby enhancing their blood circulation and tumor delivery after multiple injections.

Graphical abstract: Immune-camouflaged graphene oxide nanosheets for negative regulation of phagocytosis by macrophages

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Publication details

The article was received on 08 Mar 2017, accepted on 19 Jun 2017 and first published on 22 Jun 2017


Article type: Paper
DOI: 10.1039/C7TB00648A
Citation: J. Mater. Chem. B, 2017, Advance Article
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    Immune-camouflaged graphene oxide nanosheets for negative regulation of phagocytosis by macrophages

    G. Shim, W. Miao, S. Ko, G. T. Park, J. Y. Kim, M. G. Kim, Y. B. Kim and Y. K. Oh, J. Mater. Chem. B, 2017, Advance Article , DOI: 10.1039/C7TB00648A

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