Stabilized Nanosponge Particles Sequester and Neutralize Toxins in the Bloodstream

By LabMedica International staff writers
Posted on 23 Apr 2013

Novel "nanosponges" comprising a biocompatible nanoparticle core coated with fragments of natural red blood cell membranes are able to absorb and neutralize a wide range of pore-forming toxins.

Investigators at the University of California, San Diego (UCSD; USA) had previously used the 85-nanometer diameter nanosponges to deliver chemotherapeutic drugs directly to tumors. The red blood cell membrane coating rendered the nanoparticles invisible to immune system response.

Image: Nanosponge Cross Section. Engineers at the University of California, San Diego have invented a "nanosponge" capable of safely removing a broad class of dangerous toxins from the bloodstream, including toxins produced by MRSA (methicillin-resistant Staphylococcus aureus), E Coli, poisonous snakes, and bees. The nanosponges are made of a biocompatible polymer core wrapped in a natural red blood cell membrane (Photo courtesy of Zhang Research Lab, UC San Diego Jacobs School of Engineering).

Image: Nanosponge TEM (Transmission electron microscopy) image demonstrated that the nanosponges are approximately 85 nanometers in diameter (Photo courtesy of Zhang Research Lab, UC San Diego Jacobs School of Engineering).

In the current study nanosponges were used to sequester and neutralize toxins circulating in the bloodstream of a mouse model. Results published in the April 14, 2013, online edition of the journal Nature Nanotechnology revealed that preinoculation with nanosponges enabled survival of 89% of mice challenged with a lethal dose of MRSA alpha-hemolysin toxin. Treatment with nanosponges after administration of the lethal dose of toxin resulted in 44% survival. Administering nanosponges and alpha-hemolysin toxin simultaneously at a toxin-to-nanosponge ratio of 70:1 neutralized the toxin and caused no discernible harm to the animals.

In these experiments, the nanosponges were found to have a half-life of 40 hours in the blood circulation of the mice. Eventually the animals' livers metabolized both the nanosponges and the sequestered toxins, with the liver suffering no apparent damage.

"This is a new way to remove toxins from the bloodstream," said senior author Dr. Liangfang Zhang, professor of nanoengineering at UCSD. "Instead of creating specific treatments for individual toxins, we are developing a platform that can neutralize toxins caused by a wide range of pathogens, including MRSA and other antibiotic resistant bacteria."

Related Links:
University of California, San Diego