Microfabricated electrolysis pump system for isolating rare cells in blood

Abstract

An integrated system for immunomagnetic separation of rare cells from blood is presented. A micromachined device was fabricated by bonding silicon die with etched structures to a glass cover plate on which electrodes are defined. Electrolytic generation of gas from 0.50 M KNO 3 (aqueous) provided pumping actuation for a device that performed the capture and purification of rare cells spiked into a 7.5 µl reconstituted blood sample. The system consisted of two pumps, a sample and a wash buffer meander reservoir, and a main channel for magnetic field trapping of rare cells captured by antibody-coated magnetic beads. A maximum pumping rate of 1.4 ± 0.1 µl min −1 was obtained at a current of 180 µA, and the maximum blood sample volume delivered to the capture bed was 6.5-7 µl. The trapped cells could be washed with the buffer from the second pump and then delivered to the exit port of the chip after removing the magnetic field.

A micropillar‐integrated smart microfluidic device for specific capture and sorting of cells

“…Psychari et al [25] constructed a new microfluidic device for cell sorting using superparamagnetic nanoparticles. Jurkat cells were isolated from blood with anti-CD3 coated magnetic particles [26]. Blood and particles were mixed off-chip and then trapped in the microchannel.…”

Immunomagnetic T cell capture from blood for PCR analysis using microfluidic systems

“…The integration of magnetic trap actuator coils within a microfluidic device was also demonstrated by Ahn et al 23 Recently, we reported on the use of a magnetic bead capture chip, in which antibody coated paramagnetic beads where first mixed off-chip with blood samples, then introduced into the chip, where the target cells were captured, washed and isolated from blood. 24 Liu et al have reported a similar approach, in which the PCR step was also integrated on-chip. 3 These developments are promising, but it would be more convenient if the immunocapture reaction could also be performed in the microfluidic system, so that no external sample preparation was required.…”

Design Principles for Microfluidic Biomedical Diagnostics in Space

“…To be prudent, processes that can create bubbles must be analyzed for microgravity operation before use in space. In some cases, bubble generation is fundamental to the technique Furdui et al, 2003) and in other cases, bubbles can be an unintended consequence, e.g., of hydrolysis (Lancaster et al, 2005). Metabolic processes or biochemical reactions can create dissolved gases.…”

“…Bubbles can be used as a type of displacement pump, since they displace liquid during controlled growth. Hydrolysis can be used to generate bubbles with precision to drive flow in a microfluidic channel (Furdui et al, 2003). Deliberate creation of bubbles within a microfluidic device for space, however, should be considered with caution, since bubble management is not a trivial matter.…”