Quantum dots make bacteria more vulnerable to antibiotics. Photo: Mason Marino, University of Colorado Boulder
The problem: Bacteria are increasingly resistant to antibiotics — an estimated 23,000 people die each year in the U.S. from infections that can't be fought with existing drugs. One of the challenges is getting antibiotics into the cells.
How it works: When a particular wavelength of light hits the light-sensitive cadmium telluride nanoparticles or quantum dots, their electrons jump off and attach to surrounding oxygen molecules. Those "superoxides" enter bacteria and, while the cell's defenses focus on clearing them, antibiotics can enter. The University of Colorado Boulder researchers tested the nanoparticles with five different antibiotics and drug-resistant Klebsiella pneumoniae and Staphylococcus aureus (MRSA).
Temming points out: "One limitation of this treatment is that the green light that activates the nanoparticles can shine through only a few millimeters of flesh, says coauthor Prashant Nagpal... So these quantum dots could probably be used only to treat skin or accessible wound infections."