A BRAIN-boring robot that burrows its way through tissue in the same way a wasp digs through wood could make keyhole surgery safer.
The female wood wasps of the Siricidae family use a needle-like ovipositor to deposit eggs inside pine trees. This has two dovetailed shafts, each covered in backward-facing teeth. To bore into wood, the wasp rapidly oscillates each shaft backwards and forwards. As the shaft is pulled backwards, its sharp teeth catch in the wood鈥檚 tissue and prevent it from retreating, so with each oscillation the ovipositor takes a small step forward. The tension created by the gripping teeth braces the shaft and prevents the needle from buckling or breaking. 鈥淚t can insinuate itself into the tissue with the minimum amount of force,鈥� says at Imperial College London.
Now, a team that includes Rodriguez y Baena is mimicking this mechanism to create a medical probe. The researchers have developed a prototype silicon needle consisting of two shafts with 50-micrometre-long fin-shaped teeth. Motors oscillate the two shafts to propel the device forwards in the same way as the wood wasp鈥檚 ovipositor (see diagram).
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Preliminary tests have shown that the device can crawl across the surface of brain-like gels and burrow its way into pig muscle tissue. The team will present the probe at the conference in Bangkok, Thailand, in February.
Unlike existing rigid surgical probes, the device will be flexible enough to move along the safest possible route, bypassing high-risk areas of the brain during surgery, for example. It could also reduce the number of incisions needed to deliver cancer therapies to different parts of a tumour, as it can burrow its way to hard-to-reach areas.
鈥淚t will be flexible enough to travel the safest route, bypassing high-risk areas of the brain during surgery鈥�
, who works on bio-inspired engineering at the University of Reading, UK, says that the device is likely to be better suited to harder, fibrous tissues like bone and muscle than to soft brain tissue.
