Researchers at the University of California, San Diego have developed a nanosponge, a small particle that acts as a decoy for a wide variety of toxins that create pores in the cell membrane. This includes toxins produced by bacteria such as MRSA and E. coli, poisonous snakes, sea anemones, scorpions and bees. Unlike most other antitoxins, the nanosponges work regardless of the molecular structure of the toxin and thus do not need to be custom synthesized for individual toxins.
Pore-forming toxins create pores in the cell membrane (with red blood cells being a prime target), disrupting the normal tight regulation of the passage of molecules into and out of the cell. This leads to ions, amino acids and nucleotides leaking out of the cell, disrupting protein synthesis and cell signaling pathways, and water entering the cell, causing it to swell and eventually burst. The nanosponges, which are 3,000 times smaller than red blood cells, consist of a polymeric nanoparticle core surrounded by red blood cell membranes. The membrane acts as a decoy for the pore-forming toxins, while the core allows the particle to keep its structure while it does its job. In a single dose a large number of nanosponges is injected, greatly outnumbering red blood cells. The nanosponges not only arrest the toxins, but also lock them in to keep them away from other red blood cell membranes.
To show the effectiveness of their treatment, the researchers conducted a study in mice. A lethal dose of alpha-haemolysin toxin from MRSA was injected in the tail-vein of mice, which normally causes acute death. In the control group, which didn’t receive any treatment, all mice died as expected. However, when nanosponges were injected two minutes before administrating the toxin, an impressive 89 percent of mice survived. When the nanosponges were injected two minutes after administrating the lethal dose, still 44 percent survived. Further study on the surviving mice showed that after doing their job, the nanosponges accumulated primarily in the liver, and liver biopsies showed that they appeared to be safely metabolized there without any liver damage. The findings were published in Nature Nanotechnology.
Article in Nature Nanotechnology: A biomimetic nanosponge that absorbs pore-forming toxins…