Photoexcited quantum dots for killing multidrug-resistant bacteria

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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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Figure 1: CdTe-2.4 quantum dots induce light-activated inhibition of growth in MDR bacterial strains.
Figure 2: The effect of CdTe-2.4 is specific to the reduction and oxidation potentials.
Figure 3: Formation of intracellular redox species which do not effect HEK 293T cells, and a photo-proliferative response using CuInS2.

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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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.

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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.

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Correspondence to Anushree Chatterjee or Prashant Nagpal.

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The authors have filed a patent on this technology.

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Courtney, C., Goodman, S., McDaniel, J. et al. Photoexcited quantum dots for killing multidrug-resistant bacteria. Nature Mater 15, 529–534 (2016).

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