Researchers have developed biomimetic nanosponges that could prove an effective way of dealing with antibiotic-resistant infections. Each nanosponge is a tiny polymer-based particle measuring 85nm (around one 300,000th of an inch) across that's been wrapped in a red blood cell membrane. When scientists injected the material into mice, toxic proteins attached themselves to the nanosponges and were harmlessly transported to the liver for removal.

The nanosponges were developed at the University of California, San Diego by a team led by Professor Liangfang Zhang. A clinical trial on mice tested their efficacy against a lethal dose of a bacterial toxin from Methicillin-resistant Staphylococcus aureus (MRSA), and found that it greatly increased the rodents' chance of survival. When dosed with the nanosponges before being injected with the toxin, 89 percent of the mice survived. When treated after being infected, 44 percent of the mice lived. When dosed at exactly the same time, the mice suffered no adverse effects, even with a 70-to-one ratio of toxin and nanosponges. Tests in 2011 showed that the sponges could stay inside the bodies of mice for almost three days.

Further tests are needed but the future looks bright for nanosponges

The results of the clinical trial are certainly encouraging, but further tests are needed to gauge the nanosponges' ability to save human lives. Professor Jean-Christophe Leroux of the Institute of Pharmaceutical Studies at the Swiss Federal Institute of Technology tells Discovery News that it's not clear if the approach will work with humans, and also notes that infections would have to be treated very early as damage can occur quite quickly. The nanosponges will also only be effective against certain types of infections — toxins that attack the nervous system, for example, would be unaffected. Even so, Professor Zhang hopes to move to human trials soon. The path to seeing their research approved for real-world use could be smoother for Zhang's team than most. The polymer used for the nanosponges has already been approved by the FDA, and the red blood cell membrane is taken from the body, meaning there are no new chemical compounds to approve.