Baking-powder driven centripetal pumping controlled by event-triggering of functional liquids

This paper reports radially inbound pumping by the event-triggered addition of water to on-board stored baking powder in combination with valving by an immiscible, high-specific weight liquid on a centrifugal microfluidic platform. This technology allows making efficient use of precious real estate near the center of rotation by enabling the placement of early sample preparation steps as well as reagent reservoirs at the spacious, high-field region on the perimeter of the disc-shaped rotor. This way the number of process steps and assays that can be integrated on these of this “Lab-on-a-Disc” (LoaD) cartridge can be significantly enhanced while maintaining minimum requirements on the intrinsically simple, spindle-motor based instrumentation

Xurography actuated valving for arbitrary timing of centrifugal flow control in parallelized multi-step bioassays

Here we introduce a new, instrument controlled valving scheme for the centrifugal platform which is based upon dissolvable film (DF) technology. Liquid, restrained at any point upon the disc, is prevented from wetting a DF via a trapped gas pocket. From this pocket a pneumatic channel runs to a sealed vent located on the top surface of the disc. Controlled scouring of this seal by a robotic knifecutter permits venting of the trapped gas, and thus actuation of the valve. To demonstrate the potential of these valves, we present a disc developed towards a biplex liver assay panel

Centrifugally automated Solid-Phase Extraction of DNA by immiscible liquid valving and chemically powered centripetal pumping of peripherally stored reagents

This paper presents two flow-control technologies for use on centrifugal Lab-on-a-Disc systems. The first, immiscible liquid valving, selectively blocks microfluidic channels using a high-density liquid fluorocarbon (FC- 40). Used with a specific channel geometry, the FC-40 can permit liquid to enter a chamber but prevents it flowing back along the same path and so acts as “liquid” check-valve. The same liquid can be combined with a water-dissolvable film to provide an extremely robust liquid routing structure. The second technology uses CO2 gas, created by wetting of commodity baking powder by water, to centripetally pump liquid from the periphery of the disc to the centre of the disc. The technologies are combined with valving schemes based on strategically placed, solvent-selective dissolvable films (DFs) to demonstrate repeated pumping of a liquid sample from the edge of the disc to the centre of the disc. The flow-control technologies are then combined to demonstrate fully automated Solid-Phase Extraction (SPE) of DNA with reagent storage on the periphery of the disc. We report an extraction efficiency of 47% measured relative to commercial spin-columns