October 31, 2007 -- A research group at Tokai University has developed a way to fabricate metal tubes that are as small as 50 microns in outer diameter and 25 microns inside, making them no larger than the proboscis of a mosquito and hold the promise of being developed into equally painless syringe needles.
In the procedure, titanium is sputtered onto a copper wire which is then melted and removed, leaving just the titanium behind in the shape of a hollow tube. This is the same method of sputtering used in the semiconductor manufacturing process, only the metal molecules are sputtered on copper wire instead of a flat substrate.
Wires are normally circular, but by changing the shape of the wire the tube can be designed with a polygonal cross-section. The university group plans to make the microscopic tubes in different shapes to see which shape is best as a painless syringe needle.
Syringes are now made by sharpening metal materials, and the smallest needles are around 200 microns in outer diameter. Moreover, they tend to be made from metals like chrome and nickel that can be harmful to the environment.
The new procedure uses titanium, which is biocompatible, and the process itself is based on conventional semiconductor manufacturing equipment so a chipmaker could become involved in production with no major investment.
Source: Asia Pulse
