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Volume 91 Issue 16 | p. 36 | Concentrates
Issue Date: April 22, 2013

Nanosponges Soak Up Toxins

Tiny membrane-coated particles keep poisonous proteins away from healthy cells, save mice injected with lethal doses
Department: Science & Technology
News Channels: Biological SCENE, Materials SCENE, Nano SCENE
Keywords: toxin, nanosponge, red blood cells, anti-toxin therapies
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Nanosponges (cutaway shown) serve as decoys for pore-forming toxins, sequestering them from healthy cells.
Credit: Nat. Nanotechnol.
A cutaway view of a bone-colored sphere covered in an orange spongy material dotted with purple, blue, and green particles.
 
Nanosponges (cutaway shown) serve as decoys for pore-forming toxins, sequestering them from healthy cells.
Credit: Nat. Nanotechnol.
[+]Enlarge
Nanosponges protect red blood cells, which collect in the bottom of a centrifuged vial, from being split open by the bacterial toxin α-hemolysin (right). Without the nanosponges (left), the toxin spills and disperses the cells’ contents, including the red-tinted macromolecule hemoglobin, throughout the vial.
Credit: Nat. Nanotechnol.
Two centrifuge vials. On the left the contents are red, on the right they are a colorless. Both are clear.
 
Nanosponges protect red blood cells, which collect in the bottom of a centrifuged vial, from being split open by the bacterial toxin α-hemolysin (right). Without the nanosponges (left), the toxin spills and disperses the cells’ contents, including the red-tinted macromolecule hemoglobin, throughout the vial.
Credit: Nat. Nanotechnol.

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.

 
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