Letter | Published:

Photoexcited quantum dots for killing multidrug-resistant bacteria

Nature Materials volume 15, pages 529534 (2016) | Download Citation

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Abstract

Multidrug-resistant bacterial infections are an ever-growing threat because of the shrinking arsenal of efficacious antibiotics1,2,3,4. Metal nanoparticles can induce cell death, yet the toxicity effect is typically nonspecific5,6,7,8. Here, we show that photoexcited quantum dots (QDs) can kill a wide range of multidrug-resistant bacterial clinical isolates, including methicillin-resistant Staphylococcus aureus, carbapenem-resistant Escherichia coli, and extended-spectrum β-lactamase-producing Klebsiella pneumoniae and Salmonella typhimurium. The killing effect is independent of material and controlled by the redox potentials of the photogenerated charge carriers, which selectively alter the cellular redox state. We also show that the QDs can be tailored to kill 92% of bacterial cells in a monoculture, and in a co-culture of E. coli and HEK 293T cells, while leaving the mammalian cells intact, or to increase bacterial proliferation. Photoexcited QDs could be used in the study of the effect of redox states on living systems, and lead to clinical phototherapy for the treatment of infections.

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Change history

  • 04 February 2016

    In the original version of this Letter published online, the x axis of Fig. 2e was labelled incorrectly and the middle and righthand labels should have read 'CdSe-2.6' and 'CdSe-2.4', respectively. This has been corrected in all versions of the Letter.

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Acknowledgements

We acknowledge financial support from W. M. Keck Foundation and University of Colorado startup funds, and NSF Graduate fellowship (DGE 1144083) to C.M.C. We would also like to thank T. Nahreini and S. Bryant for allowing use of their cell culture facilities.

Author information

Author notes

    • Colleen M. Courtney
    •  & Samuel M. Goodman

    These authors contributed equally to this work.

Affiliations

  1. Chemical and Biological Engineering, University of Colorado, Boulder, Boulder, Colorado 80303, USA

    • Colleen M. Courtney
    • , Samuel M. Goodman
    • , Jessica A. McDaniel
    • , Anushree Chatterjee
    •  & Prashant Nagpal
  2. Division of Infectious Diseases, University of Colorado, Denver, Aurora, Colorado 80045, USA

    • Nancy E. Madinger
  3. BioFrontiers Institute, University of Colorado Boulder, Boulder, Colorado 80303, USA

    • Anushree Chatterjee
    •  & Prashant Nagpal
  4. Materials Science and Engineering, University of Colorado, Boulder, Boulder, Colorado 80303, USA

    • Prashant Nagpal

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Contributions

P.N. and A.C. conceived the idea and designed the experiments. C.M.C., S.M.G. and J.A.M. conducted the experiments. N.E.M. prepared the clinical isolates and provided the samples. P.N., A.C., C.M.C. and S.M.G. analysed the experimental data and wrote the paper. All the authors discussed the results and edited the manuscript.

Competing interests

The authors have filed a patent on this technology.

Corresponding authors

Correspondence to Anushree Chatterjee or Prashant Nagpal.

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DOI

https://doi.org/10.1038/nmat4542

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