It is hoped that advances in microchip technology will help clinicians, in the future, to perform tests to detect and diagnose hundreds of diseases, including cancer in it’s early stages, from a drop of blood.
Nicholas Fang, associate professor of mechanical engineering at the Massachusetts Institute of Technology in the US, has come up with a simple technique that cuts the time and cost of sensor manufacture.
Today scientists fabricate nano-sensors using electron-beam lithography, a very expensive and time-consuming technique. Fang’s engraving technique involves etching nano-sized patterns on metallic surfaces using a small, voltage activated stand made from glass.
The engravings act as optical antennae that identify a single molecule, by detecting its unique wavelength. Researchers of the future may be able to use the new glass stamp approach to scale up the manufacture of sensors.
Fang says he was inspired by glassblowers, who use their skills to form bottles and beakers. “Even though we think of glass as fragile, at the molten stage, it is actually very malleable and soft, and can quickly and smoothly take the shape of a plaster mould. That’s at a large scale, but amazingly it works very well at a small scale too, and at very high speed,” says Fang.
In the MIT lab the researchers filled a small syringe with glass particles and heated the needle to melt the glass inside. They then pressed the molten glass onto a master pattern, forming a mould that was hardened when cooled.
The team then pressed the glass mould onto a flat silver substrate, and applied a small, 90-millivolt electric potential above the silver layer.
The voltage stimulated ions in both surfaces, and triggered the glass mould to essentially etch into the metal substrate.
Patterns of microscopic dots, 30 nanometres wide were created, in patterns including an ionic column, at a resolution more precise than currently used nano-imprint lithography.