Handout image issued by the University of California of a “nanosponge” which can circulate through the bloodstream mopping up dangerous toxins, including the one produced by MRSA. Photo: Zhang Research Lab/PAMicroscopic sponges that circulate through the bloodstream mopping up toxins can overcome the superbug MRSA, studies have shown.
The ball-shaped ‘nanosponge’, which is 3,000 times smaller than a red blood cell, soaks up dangerous chemicals and transports them to the liver where they are broken down.
In tests on mice, US scientists successfully neutralised the alpha-haemolysin toxin produced by Methicillin Resistant Staphylococcus Aureus (MRSA).
Pre-injection with the nanosponges allowed 89 per cent of mice to survive normally lethal infections. Treatment after infection saved 44 per cent of the animals.
The sponges can also combat toxin from the food bug Escherichia coli (E.coli) and venom from poisonous snakes and bees.
Study leader Liangfang Zhang, from the University of California at San Diego, said: “This is a new way to remove toxins from the bloodstream.
“Instead of creating specific treatments for individual toxins, we are developing a platform that can neutralise toxins caused by a wide range of pathogens, including MRSA and other antibiotic resistant bacteria.”
The scientists aim to develop approved nanosponge therapies that can be used to treat human patients.
“One of the first applications we are aiming for would be an anti-virulence treatment for MRSA,” said co-author Che-Ming Hu. “That’s why we studied one of the most virulent toxins from MRSA in our experiments.”
The findings were reported in the journal Nature Nanotechnology.
Each polymer nanosponge measures just 85 nanometres across, or 85 millionths of a millimetre.
To evade the immune system, the sponge balls are disguised as red blood cells by wrapping them in corpuscle membranes.
The cloaking allows the nanosponges to act as decoys, attracting toxins that would otherwise be drawn to red blood cells.
The toxins inflict damage by punching holes through cell membranes. When they encounter a nanosponge, they break through its outer surface and become trapped. In this way, the harmful molecules are diverted away from vulnerable living cells.
Eventually the nanosponges reach the liver, where both they and their toxic cargo are metabolised and rendered harmless.
The tests showed no evidence of any damage to the liver.
An army of thousands of nanosponges can be administered with a single injection. Their capacity for absorbing dangerous substances depends on the type of toxin, the research showed.
In mice, the nanosponges were able to neutralise MRSA toxin with no side effects when they outnumbered the toxic molecules by 70 to one.