Microfluidics research is expensive. Or is it? Canadian researchers have made prototype microfluidic chips using only a simple off-the-shelf wax printer.

Christopher Backhouse's team from the University of Alberta used a wax printer, which jets molten wax onto a plastic sheet instead of ink onto paper, to print a 3D pattern or relief of the desired chip. They then poured poly(dimethylsiloxane), a type of polymer often used to produce microfluidic chips, onto the relief. After curing, the chip can be peeled from the relief giving a prototype in a matter of hours.

'We hope that this simple method of producing chips will inspire others to investigate the possibilities of microfluidics,' said Backhouse. 'Until now many researchers have been dissuaded from investigating them because of the high cost of the equipment, the need to work in dedicated clean rooms and the investment in training staff required to produce chips by more traditional methods. The fact that a preliminary result can be achieved in days rather than months is important,' he said.

Producing smooth-walled channels in the polymer is essential for many applications of microfluidics, and this requirement has meant that other potentially simple 'print-and-pour' methods have not been entirely successful. In this case, however, the use of wax allowed the team to smooth the relief by a simple heat treatment. They then demonstrated that the chip worked effectively to separate some DNA; not shown before with a print-and-pour chip.

'We were delighted with the efficiency of the DNA separation,' said Backhouse. 'The next challenge for this type of technology will be to try and fabricate the multilayer, three-dimensional chips required for more complex processes.'

Stephen Davey