Nanosponges hold promise for superbug treatments

Gel-filled “nanosponges” able to mop up the toxins produced by bacteria could be used to treat antibiotic-resistant “superbug” infections such as MRSA a team of US researchers has claimed.

MRSA (methicillin-resistant Staphylococcus aureus) is type of bacterial infection that is increasingly resistant to a number of widely used antibiotics.

Developed by a team at the University of California in San Diego, and described in the journal Advanced Materials, the new treatment has been proven to minimise the growth of skin lesions on mice infected with MRSA without the use of antibiotics.

Each nanosponge is a nanoparticle coated in a red blood cell membrane. This coating disguises the nanosponges as red blood cells, which are the real targets of the harmful toxins produced by MRSA. By masquerading as red blood cells, the nanosponges attract harmful toxins and remove them from the bloodstream.

It’s believed that by removing these toxins – which act a defence mechanism for the bacteria – the bacteria become significantly weakened and exposed, allowing the body’s immune system to kill them more easily without the use of drugs.

Nanosponges alone are difficult to use on local tissues because they diffuse away to other parts of the body very quickly, however mixing them into a hydrogel enables billions of nanosponges to be held in one place so that they can remove toxins at the infected spot.

In trials on mice, the researchers showed that the treatment kept down the size of skin lesions caused by MRSA infections. The team also showed that the hydrogel was effective at holding the nanosponges in place within the body. Two days after the material was injected underneath the skin of a mouse, nearly 80 percent of the nanosponges were still found at the injection site.