Nanosponges Soak Up Antibiotic-resistant Bacteria and Toxins

Survival rates in mice infected with deadly bacteria dramatically increase when administered the nanosponges

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Nanosponges Soak Up Antibiotic-resistant Bacteria and Toxins
University of California, San Diego

Researchers at the University of California, San Diego, have developed a nanoparticle that mimics a human blood cell so that it can circulate through our bloodstream soaking up bacterial infections and toxins. These so-called ‘nanosponges’ are expected to be particularly effective in treating bacterial infections that have developed an immunity to antibiotic treatments—and also for treating venoms from snake bites.

The nanosponges are made up of a biocompatible polymer core and covered by an outer layer of red blood cell membrane. With a diameter of 85 nanometers, the nanosponges are 3000 times smaller than a human blood cell, so in a single infusion of nanosponges into the blood stream they would easily outnumber the red blood cells, and thus intercept most of the attacking toxins before they damaged the actual blood cells.

A video containing a description of the nanoparticles, along with an animation of how the particles would circulate through our bloodstream soaking up toxins can be seen below.

“This is a new way to remove toxins from the bloodstream,” said Liangfang Zhang, a nanoengineering professor at UC San Diego and the senior author on the study, in a press release. “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 methicillin-resistant staphylococcus aureus (MRSA) and other antibiotic resistant bacteria.”

In the research, which was published in the journal Nature Nanotechnology (“A biomimetic nanosponge that absorbs pore-forming toxins”), the UCSD team demonstrated how the nanosponges target pore-forming toxins (so-called because of their ability to poke holes in cells and kill them), such as MSRA. In their lab studies, the researchers found that 89 percent of mice inoculated with the nanosponges survived subsequent infections from MRSA. And those that were administered the nanosponges after being infected had a 44 percent survival rate.

Unlike other nanotechnologies that employ bio-mimicry to duplicate a natural phenomenon for use in another purpose, such as nanochannels for batteries that mimic the channels found in proteins,  this nanoparticle is more like bio-‘trickery’—a wolf in sheep's clothing. The nanoparticles are hidden within the husks of red blood cells so that the immune system is tricked into not attacking them as they circulate through the bloodstream.

This so-called red blood cell cloaking technology had been developed two years ago by Zhang and his team to deliver cancer treatments to tumor sites in the body. They have repurposed it here with the nanosponges and it appears to be a repeatable and scalable process. Some blood is drawn from the patient and then put into a centrifuge to separate out the red blood cells. The red blood cells are then placed in a solution that causes them to swell and burst leaving their outer surface, which is then mixed with the polymer nanoparticles, coating them. Not much blood is needed since one red blood cell membrane can cover thousands of these nanosponges.

The researchers seem intent on getting this therapy into clinical trials as quickly as possible.

Photo/Video: University of California, San Diego

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