Nanosponges Soak Up Toxins

To treat patients infected with protein toxins, doctors must know the origin of the poisons—whether they come from bacteria, snake venom, or elsewhere. That’s because small-molecule inhibitors or antibody therapies each deactivate toxins by binding to protein-specific structural features. A research team at the University of California, San Diego, however, has designed a new detoxification therapy that works against a whole class of toxins (Nat. Nanotechnol., DOI: 10.1038/nnano.2013.54). These pore-forming toxins kill cells, including red blood cells, by punching holes in their membranes. The UCSD researchers tricked these troublesome toxins into sticking to particles, dubbed nanosponges, that look like miniature cells from the outside. To make the decoy nanomaterials, the researchers, led by chemical engineer Liangfang Zhang, envelop poly(lactic-co-glycolic acid) nanoparticles with membranes extracted from the red blood cells of mice. When the team administered the 85-nm-diameter nanosponges to mice two minutes prior to a lethal dose of the bacterial toxin α-hemolysin, 89% of the rodents survived. Administered to mice two minutes after a lethal dose, the nanosponges saved 44% of the animals. Zhang says his team is now testing nanosponges coated with membranes from human red blood cells.