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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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.
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). https://doi.org/10.1038/nmat4542
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