British scientists are mimicking the function of wood-boring wasps to create a specialized probe for performing brain surgeries. The wasps use ovipositors, or specialized shafts that move counter to each other, to drill into trees while causing little damage to the tissue of the plant. This property motivated Ferdinando Rodriguez y Baena at Imperial College London to attempt to reproduce the mechanics for surgical purposes.
From the Imperial College London project page:
The ovipositor of the wood wasp, Sirex noctilio, for example, has the main function of delivering eggs through a hollow tube along its length. Its tip is about 0.2~0.3mm in diameter and can drill to a depth of up to 20mm into the sapwood of a tree. The applicability of the wood wasp’s anatomy resides in the mechanism of drilling, which does not require rotary motion or impaction.
The ovipositor is made of two interlocked halves, or “valves,” rather like the zip on a “zip-lock” polyethylene bag, which slide relative to each other. Backward pointing teeth (numbered in Fig. 1b) hold on to the substrate, resisting pulling forces. The pull on one of the valves provides stabilization along the length of the ovipositor to prevent buckling so that the other valve can be pushed with an equal and opposite force, to produce a net force near zero. The reciprocating motion of the two valves drives the ovipositor’s penetration, as one valve is pushed deeper into the wood stabilized by tension generated in the other valve. Since there is no net force in the ovipositor assembly, there are no stability problems and there is no theoretical limit on its length.
Project page: Biomimetic flexible and steerable probe for neurosurgery
Robocast project page…
White paper from 2007 IEEE International Conference on Robotics and Automation – Workshop on Biomimetic Robotics: Biomimetics and robotics for space applications: challenges and emerging technologies (.pdf)
(hat tip: NewScientist)