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Gold nanocages covered by smart polymers for controlled release with near-infrared light

Nature Materials volume 8, pages 935939 (2009) | Download Citation



Photosensitive caged compounds have enhanced our ability to address the complexity of biological systems by generating effectors with remarkable spatial/temporal resolutions1,2,3. The caging effect is typically removed by photolysis with ultraviolet light to liberate the bioactive species. Although this technique has been successfully applied to many biological problems, it suffers from a number of intrinsic drawbacks. For example, it requires dedicated efforts to design and synthesize a precursor compound for each effector. The ultraviolet light may cause damage to biological samples and is suitable only for in vitro studies because of its quick attenuation in tissue4. Here we address these issues by developing a platform based on the photothermal effect of gold nanocages. Gold nanocages represent a class of nanostructures with hollow interiors and porous walls5. They can have strong absorption (for the photothermal effect) in the near-infrared while maintaining a compact size. When the surface of a gold nanocage is covered with a smart polymer, the pre-loaded effector can be released in a controllable fashion using a near-infrared laser. This system works well with various effectors without involving sophisticated syntheses, and is well suited for in vivo studies owing to the high transparency of soft tissue in the near-infrared region6.

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This work was supported by a 2006 Director’s Pioneer Award from the NIH (DP1 OD000798). Part of the work was carried out at the Nano Research Facility (NRF), a member of the National Nanotechnology Infrastructure Network (NNIN), which is supported by the NSF under award no. ECS-0335765. NRF is part of School of Engineering and Applied Science at Washington University in St Louis.

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    • Mustafa S. Yavuz
    • , Yiyun Cheng
    •  & Jingyi Chen

    These three authors contributed equally to this project


  1. Department of Biomedical Engineering, Washington University, St Louis, Missouri 63130, USA

    • Mustafa S. Yavuz
    • , Yiyun Cheng
    • , Jingyi Chen
    • , Claire M. Cobley
    • , Qiang Zhang
    • , Matthew Rycenga
    • , Jingwei Xie
    • , Chulhong Kim
    • , Kwang H. Song
    • , Andrea G. Schwartz
    • , Lihong V. Wang
    •  & Younan Xia


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M.S.Y. and Y.C. synthesized the alizarin-PEG dye and polymers, carried out the loading and controlled-release experiments and did data analysis. J.C., C.M.C. and A.G.S. carried out the synthesis, surface modification and characterization of Au nanocages. C.M.C. and Q.Z. synthesized the Ag nanocubes. M.R. analysed the mechanism for laser-triggered release. C.K., K.H.S. and L.V.W. were involved in the planning of laser-triggered release experiments and helped with the analysis on Au nanocage melting. J.C. and J.X. conducted the cell viability, protein assay and enzyme activity assays. Y.X. conceived the strategy, supervised the experiments and prepared different versions of the manuscript.

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Correspondence to Younan Xia.

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