Microbot motors fit to swim human arteries

A range of complex surgical operations necessary to treat stroke victims, confront hardened arteries or address blockages in the bloodstream are about to be made safer as researchers from Monash University put the final touches to the design of micro-motors small enough to be injected into the human bloodstream.

A research paper published in IOP Publishing’s Journal of Micromechanics and Microengineering details how researchers from the University’s Micro/Nanophysics Research laboratory are harnessing piezoelectricity, the energy force most commonly used to trigger start a gas stove, to produce microbot motors just 250 micrometres or a quarter of a millimetre wide.

The motor has been named the "Proteus motor" after the miniature submarine that travelled through the human body in the science fiction movie Fantastic Voyage.

Research team leader Professor James Friend said methods of minimally invasive surgery such as keyhole surgery were preferred by surgeons and patients because of the damage avoided when contrasted against cut and sew operations.

"Serious damage during minimally invasive surgery is however not always avoidable and surgeons are often limited by the width of a catheter tube for example, which in serious cases, can fatally puncture narrow arteries," Professor Friend said.

"Remote controlled miniature robots small enough to swim up arteries could save lives by reaching parts of the body, like a stroke-damaged cranial artery, that catheters have previously been unable to reach.

"With the right sensor equipment attached to the microbot motor, the surgeon’s view can be enhanced and the ability to work remotely also increases the surgeon’s dexterity."

Professor Friend and his team believe piezoelectricity is the most suitable energy force for micro motors because the engines can be scaled down while remaining forceful enough for motors to swim against the blood’s current and reach spots difficult to operate upon.

Piezoelectricity is most commonly found in quartz watches and gas stoves. It is based on the ability of some materials to generate electric potential in response to mechanical stress.

The team has produced prototypes of the motors and is now working on ways to improve the assembly method and the mechanical device which moves and controls the micro-motors.

(Source: Monash University: Journal of Micromechanics and Microengineering: February 2009)