Nanoparticles may be a silver bullet against brain-eating amoeba
Naegleria fowleri is a pretty scary amoeba. Found in warm freshwater lakes, rivers and hot springs, it enters a person's body through their nose, then proceeds to kill them by eating their brain. Infections are rare, fortunately, and they may also soon be more treatable thanks to the use of silver nanoparticles.
Although Naegleria fowleri infections (aka primary amoebic meningoencephalitis) are usually fatal, attempts to treat them involve using antimicrobial drugs. Large doses of these drugs need to be given in order for them to cross the blood-brain barrier, which is a highly selective semipermeable border that prevents potentially toxic elements in the blood from entering the brain.
As a result of these high doses, severe side effects are common.
Led by Dr. Ayaz Anwar, researchers from Malaysia's Sunway University instead looked to three existing anti-seizure drugs – diazepam, phenobarbitone and phenytoin – that were already known to easily cross the blood-brain barrier. In lab tests, these drugs were tried both alone, and when attached to silver nanoparticles. The latter have antimicrobial qualities of their own, plus they have previously been used to improve the delivery of other drugs.
It was found that while each of the drugs was able to kill Naegleria fowleri unaided, they were much more effective when combined with the nanoparticles – adjacent human cells were left unharmed. Anwar and colleagues believe that the drug/nanoparticle combo may kill the amoeba by binding to protein receptors or ion channels on its outer membrane.
A paper on the research was recently published in the journal ACS Chemical Neuroscience.