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, who teaches physics at Massachusetts’ Cambridge Rindge and Latin School, collaborates with Harvard University’s School of Engineering and Applied Sciences (SEAS), 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.
Childs is now working with SEAS Director of Instructional Technology Dr. Anas Chalah, to perfect the system. Already, he says, they can design and build a chip in a single afternoon. Although the photocopier microfluidics are not as precise as their commercially-produced counterparts, they could prove to be an invaluable educational aid for physics students, who will be able to design and build their own microfluidic devices.
All photos courtesy Harvard University.