Worms eye views obtained in intestines

Small devices are being developed to make their way along the human gut, inspired by studies of intestinal worms. Completely autonomous, they use a novel method of locomotion of potential interest to makers of inspection devices for the chemical plant and offshore industries. Exploratory capsules that can be swallowed to investigate the gut already exist. Most remarkable is the Norika 3, made by the Japanese company RF System Lab. Despite being only 9mm in diameter and 23mm long, it contains a CCD camera, four LED lamps, a tank for tissue sampling and a second tank for spray medication. It is powered by induction from a coil placed in a vest worn by the patient, which may also be used to control direction. Although it has not yet completed human testing, its projected launch price is $100, and its makers plan to eventually reduce this to less than $50. Its only limitation is that it cannot propel itself. Intestinal parasitic worms are able to do this only too well, so a European Project called BIOLOCH (BIOmimetic structures for LOComotion in the Human body has been set up to study such animals, with a view to developing biomimetic artificial 'worms'. Prototype devices were recently described by Dr Luigi Gerovasi, from the Department of Mechanical Engineering at the University of Cagliari, to a meeting hosted by the Centre for Biomimetics at the University of Reading. The devices being developed Dr Gerovasi and colleague Professor Bruno Picasso, have exteriors made in the form of a series of sawtooth profiled rings. Driven by internal vibrators, they therefore move in the direction of the inclined sides of the sawtooths and are prevented from moving in the reverse direction by the vertical sides. Early versions were propelled by rotating an eccentric weight. A more recent version, still under development, is propelled by a linear vibrator. The devices will have to be able to make their way along intestines whose diameters vary from 20mm to 70mm filled with large amounts of solid and semi-solid material. The mechanical nature of the intestinal walls also varies considerably. Equipment to measure friction coefficients between the devices and biological tissues is under construction. The Biomimetics Network for Industrial Sustainability RF System Lab Dr Luigi Gerovasi Pointers * A small camera pill, complete with lights and the ability to take samples and apply medication is now in its third version * A method has now been found to allow intestinal endoscopic devices to propel themselves, using an internal vibrator and external sawtooth profile rings.