Automated delivery of fluids in microchannels without the help of an expensive bulky instrumentation is essential for providing cost-effective and user-friendly cartridges in the field of point-of-care diagnostics. Although miniaturisation of pumps has been an intense field of research, many approaches face the loss of effectiveness upon scaling of the actuation principle or demand a bulky power supply to operate under high voltages.

IME researchers have developed a magnetically-actuated planar peristaltic pump (MP3) which is manufactured in poly (dimethysiloxane) (PDMS) by the popular soft lithography method. Hence, MP3 can be directly integrated into many microfluidic devices within the same rapid-prototyping step. The dead volume between the pump and the device can be made lithographically small. A unique feature of the pump is that its actuation relies on readily-available components: stainless-steel ball bearings coupled with revolving rare-earth magnets recovered from failed hard disk drives. A pair of ball bearing and strong rare-earth magnet acts as a non-contact magnetic spring which can deliver highly-effective compressive forces on a PDMS sheet from exterior, thereby squeezing the microchannels (as shown in figure below). These external actuating elements are reusable and simplify the overall pump prototyping.

MP3 has applications in lab-on-chip devices, particularly in disposable cartridges for point-of-care diagnostic tests. The pump characteristics will be extensively detailed in a paper which has been accepted by Lab on Chip journal (Yobas et al., Lab Chip, 2008, DOI: 10.1039/b720024b). A PCT patent application has also been filed.

MP3 working principle: The PDMS sheet (clear layer) containing a planar channel in the form of an open loop layout (filled with aqueous dye) placed on a rigid substrate (brown layer) held closely over a revolving rare-earth magnet. A ball bearing placed on the loop rolls under the influence of the revolving magnetic field pinching off the planar channel underneath. A peristaltic wave driving the liquid in the direction of rotation is generated.