A nanoscale invention inspired by the tiny hairs on a Venus Flytrap could revolutionise anti-bacterial treatments for the seriously ill.
The invention, a refinement of an existing type of machine known as a dialyser, is reported in the journal Nature Communications, by a team led by Lizhi Liu of the Beijing National Laboratory for Molecular Sciences, in China.
If antibiotics fail to defeat harmful bacteria in a patient, the next available process is to remove the person’s entire blood supply and run it through a machine – a dialyser – to scrub it. This involves extracting through one blood vessel, pumping it through the scrubber and then pushing it back into the body through another.
The practice has been available for some years now, but existing dialysers are notably inefficient. A human bloodstream flows quickly, with considerable force.
Current dialysers use a range of extraction techniques, including filtration, microfluidic devices and nanoparticle separation, but all fail to capture the bulk of the bacteria carried in the blood. Many, too, are overwhelmed by the force of the flow, and end up releasing caught microbes back into the mix.
Taking a lesson from the tiny curved hair-like structures found on the hinged capture apparatus of the Venus Flytrap (Dionaea muscipula), Liu and his colleagues constructed a substrate of three-dimensional carbon foam into which were inserted a miniature plantation of flexible polycrystalline nanowires.
As blood flows through the plantation, groups of the nanowires bend in towards each other to form a three-dimensional claw, capturing bacteria and holding them firm.
In experiments reported in the paper, the dialyser succeeded in removing 97% of bloodstream bacteria in test subjects.
The device at present is still at proof-of-concept stage and much work remains before it can be rolled out into commercial production, However, Lui and his colleagues describe it as a “major step toward the development of a nanotechnology platform that can meet evolving clinical and lifestyle needs”.
They add that in principle, the technology could be used to filter out other bloodstream microorganisms, including viruses and cancer cells.