AiJun Shen

Tongji Medical University, Shanghai, Shanghai Shi, China

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Publications (2)9.03 Total impact

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    ABSTRACT: In biomedical applications, polyethylene glycol (PEG) functionalization has been a major approach to modify nanocarriers such as nano-graphene oxide for particular biological requirements. However, incorporation of a PEG shell poses a significant diffusion barrier that adversely affects the release of the loaded drugs. This study addresses this critical issue by employing a redox-responsive PEG detachment mechanism. A PEGylated nano-graphene oxide (NGO-SS-mPEG) with redox-responsive detachable PEG shell is developed that can rapidly release an encapsulated payload at tumor-relevant glutathione (GSH) levels. The PEG shell grafted onto NGO sheets gives the nanocomposite high physiological solubility and stability in circulation. It can selectively detach from NGO upon intracellular GSH stimulation. The surface-engineered structures are shown to accelerate the release of doxorubicin hydrochloride (DXR) from NGO-SS-mPEG 1.55 times faster than in the absence of GSH. Confocal microscopy shows clear evidence of NGO-SS-mPEG endocytosis in HeLa cells, mainly accumulated in cytoplasm. Furthermore, upon internalization of DXR-loaded NGO with a disulfide-linked PEG shell into HeLa cells, DXR is effectively released in the presence of an elevated GSH reducing environment, as observed in confocal microscopy and flow cytometric experiments. Importantly, inhibition of cell proliferation is directly correlated with increased intracellular GSH concentrations due to rapid DXR release.
    Small 03/2012; 8(5):760-9. · 7.51 Impact Factor
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    ABSTRACT: A novel methoxy-poly(ethylene glycol) modified nano-graphene oxide (NGO-mPEG) was designed and synthesized as a photosensitizer (PS) carrier for photodynamic therapy of cancer. NGO with a size below 200 nm was prepared using a modified Hummers’ method. NGO was observed by AFM to exhibit a structure with single-layer graphene oxide sheets down to a few nanometers in height. Hydrophilic mPEG conjugation of NGO (NGO-mPEG) was found to enhance solubility in cell culture media. No apparent cytotoxicity of the NGO-mPEG was observed towards MCF-7 carcinoma cell line. Zinc phthalocyanine (ZnPc), a photosensitizer for photodynamic therapy, was loaded in the NGO-PEG through π-π stacking and hydrophobic interactions, with the drug loading efficiency up to 14 wt%. Hydrophobic ZnPc was internalized in MCF-7 cells, exhibiting a pronounced phototoxicity in the cells under Xe light irradiation. The results indicate a great potential of NGO-mPEG for photodynamic therapy of cancer. Keywordsnano-graphene oxide-photodynamic therapy-photosensitizer-drug delivery-biomedical application
    Science China-Chemistry 01/2010; 53(11):2265-2271. · 1.52 Impact Factor

Publication Stats

52 Citations
9.03 Total Impact Points

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Institutions

  • 2012
    • Tongji Medical University
      Shanghai, Shanghai Shi, China
  • 2010
    • Tongji University
      • Institute for Advanced Materials and Nano Biomedicine (iNANO)
      Shanghai, Shanghai Shi, China