Microfluidic technology, in which liquid is made to pass through “microchannels” that are often less than a millimeter in width, has had a profound effect on fields such as physics, chemistry, engineering and biotechnology. In particular, it has made “lab-on-a-chip” systems possible, in which the chemical contents of tiny amounts of fluid can be analyzed on a small platform. Such devices are typically made in clean rooms, through a process of photolithography and etching. This rather involved production method is reflected in their retail price, which sits around US$500 per device. Now, however, a high school teacher has come up with a way of making microfluidics that involves little else than a photocopier and transparency film.
Joe Childs, a physics teacher collaborated with Harvard via the National Science Foundation’s Research Experience for Teachers program. As part of that program, he devised a quick, simple and inexpensive method of creating reusable labs-on-a-chip.
He starts by designing the layout of the microchannels in PowerPoint, printing that image, then photocopying it onto a sheet of classroom-style transparency film. The same sheet is ran through the photocopier repeatedly, until the ink builds up sufficiently to create a raised relief model of the channels. That model serves as a negative mold, which is used to create the final working channels in a polymer chip.