Printing method makes biochips

University of Illinois researchers have fabricated tiny, three-dimensional fluidic networks that promise to reduce the size of biochips.

The researchers printed layers of organic material onto a moving platform to form a three-dimensional scaffold. They filled the scaffolding with epoxy that solidified at room temperature, then heated the structure to 50 degrees Celsius to melt and remove the scaffolding. The resulting channels were as small as 10 microns in diameter -- about twice the size of a red blood cell.

The researchers built a structure that mixed tiny amounts of fluids. In very small amounts fluids are viscous and don't readily mix.

The researchers made a series of twists and turns by filling a network of channels with a photocurable resin and shining light to solidify the resin at certain points. The prototype mixed fluids by forcing them through the turns, which formed a square, spiral tower.

The method could eventually produce networks containing hundreds of layers and interconnections, leading to more compact microfluidic devices like biomedical implants and sensors, according to the researchers.

The method could be used in commercial applications in five to ten years, according to the researchers. The work appeared in the March 23, 2003 issue of Nature Materials.