WEST LAFAYETTE, Ind. - Engineers have developed a technique that might be used to glue cells or DNA to the surfaces of computer "biochips," a technology aimed at making diagnostic devices to be implanted in the body or used to quickly analyze food and laboratory samples.
The microfabrication technique, normally used for etching electronic circuits, is instead used to fashion "micropatterns" out of a material made primarily from a polymer, or plastic, called polyethylene glycol.
"The patterns' smallest features were 5 micrometers, or about one-twentieth as wide as a human hair, which makes them as small as some cells," says Rashid Bashir, an assistant professor of electrical and computer engineering at Purdue University.
Purdue engineers previously had announced that they had made the first protein biochips, in which a protein mated to a silicon computer chip might be used to detect chemicals, microbes and disease. However, researchers say they hope to attach many other types of biological entities, such as cells and DNA, capable of quickly detecting a wider range of substances, either in the body or in laboratory samples.
The polymer micropatterning development represents a possible means of gluing these proteins, cells or DNA to a computer chip.
"This polymer layer could be the intermediate layer between the biological entities and the chip," Bashir says. "The protein would go on top of the polymer."
Unlike many synthetic materials, polyethylene glycol is not attacked by the body's immune system, making it suitable for implantation. The polymer also is ideal for microfabrication because of its unusual optical properties that allow it to be formed into patterns by using ultraviolet light in a process called photolithography, which is used in the electronics industry to etch microcircuits. The plastic is applied to the surface of silicon chips as a film and covered with a patterned, stencil-like "photomask," which is opaque i
Contact: Emil Venere