They may not look much like knives, but they are up to 10 times sharper than the advanced tools currently employed by medics.

They cut as they vibrate

The blades are etched from wafers of silicon, in a process similar to that used to make integrated circuits.

The man behind the new instruments believes they could lead to even greater precision in procedures that require very fine movements, such as cataract surgery or neurosurgery.

Amit Lal's devices use an electrical process called ultrasonics, which creates extremely fast sonic vibrations to break up tissue. The vibrations are imperceptible to the naked eye.

Biosensors

Ultrasonics has been used for years in cataract surgery but the current medical tools are made from expensive materials such as titanium, which has a tendency to overheat and needs high voltage to function.

Amit Lal: Silicon wafers are perfect materials

Lal says silicon-based tools do not experience the same problems. Being made from silicon, the machine-makers can also integrate mechanical and electrical properties together in the same device.

This means medical tools could be equipped with built-in sensors and monitors that will instantly communicate back to doctors.

"A silicon device could be designed to detect the difference between healthy and diseased tissue, and tell the doctor exactly what tissue to remove," Lal says.

He claims his ultrasonic applications can vibrate the working end of the new cutting tools up to 200,000 times per second, roughly eight times faster than any ultrasonic devices on the market.

Painless

One product that could soon come to market is an ultrasonic silicon needle that should be entirely painless.

When ultrasonic tools cut through tissue they do not pull and push the tissue in a way that causes the pain associated with conventional sharp instruments.

Silicon is quite brittle but Lal believes that if its toughness can be improved then the material has a very bright future way beyond its popular use in computer circuits.

"What I'm trying to do is promote a new silicon age," says Lal.

"If you look at history, a lot of the major periods were defined by the materials that came of age at the time.