When someone comes down with a staph infection, doctors usually treat it with an antibiotic. But more and more strains of the bacterium that cause staph infections are becoming resistant to antibiotics, leaving doctors with fewer treatment options.

Now we have word of a possible solution: a tiny set of polymer particles called "nanosponges" could one day be injected into a person's bloodstream to absorb the staph bacteria as well as E. coli, snake venom or a host of other toxins.

The nanosponges were developed by engineers at the University of California, San Diego, who have so far only tested the tiny life-savers in mice. But those tests were impressive: of the mice exposed to lethal doses of drug-resistant staph (Methicillin-resistant Staphylococcus aureus or MRSA), 44 percent survived. When the mice were treated with the nanosponges prior to being exposed to staph, the survival rate soared to 89 percent.

A paper describing the nanosponges was published April 14 in the journal Nature Nanotechnology and will be presented later this week at the UC San Diego School of Engineering's annual research and networking event known as Research Expo.

"This is a new way to remove toxins from the bloodstream," the paper's senior author, UC San Diego nanoengineering professor Liangfang Zhang, said in a prepared 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 MRSA and other antibiotic-resistant bacteria."  

The key to the nanosponges is a red blood cell-cloaking technology developed in Zhang's lab that allows the tiny polymers to be disguised as red blood cells. Once in the bloodstream, they can then serve as "decoys," absorbing toxins that would normally have attacked red blood cells.

The nanosponges are 3,000 times smaller than normal red blood cells and don't stay in the body long. In the mouse test, the polymers had a half-life of just 40 hours and were eventually metabolized by the animals' livers, with no discernible damage to the organs.

The first author of the paper, "Jack" Che-Ming Hu, is currently a post-doctoral researcher in Zhang's lab. He told Discovery News that the idea originated when they were looking at new ways to effectively deliver drugs to the entire human body. "We wanted to mimic the red blood cell because they are 'privileged.' They can go anywhere in the body." In addition to being able to go to any part of the body, the nanosponges could theoretically treat a wide range of toxins instead of only being able to treat a narrow range of conditions as is the case with current antibiotics or antivenoms.

The researchers say their next step is to plan clinical human trials for their new discovery.

Photo of nanosponge: Zhang Research Lab