Phaseguide-assisted blood separation microfluidic device for point-of-care applications

Abstract

We propose a blood separation microfluidic device suitable for point-of-care (POC) applications. By utilizing the high gas permeability of polydimethylsiloxane (PDMS) and phaseguide structures, a simple blood separation device is presented. The device consists of two main parts. A separation chamber with the phaseguide structures, where a sample inlet, a tape-sealed outlet, and a dead-end ring channel are connected, and pneumatic chambers, in which manually operating syringes are plugged. The separation chamber and pneumatic chambers are isolated by a thin PDMS wall. By manually pulling out the plunger of the syringe, a negative pressure is instantaneously generated inside the pneumatic chamber. Due to the gas diffusion from the separation chamber to the neighboring pneumatic chamber through the thin permeable PDMS wall, low pressure can be generated, and then the whole blood at the sample inlets starts to be drawn into the separation chamber and separated through the phaseguide structures. Reversely, after removing the tape at the outlet and manually pushing in the plunger of the syringe, a positive pressure will be created which will cause the air to diffuse back into the ring channel, and therefore allow the separated plasma to be recovered at the outlet on demand. In this paper, we focused on the study of the plasma separation and associated design parameters, such as the PDMS wall thickness, the air permeable overlap area between the separation and pneumatic chambers, and the geometry of the phaseguides. The device required only 2 ll of whole blood but yielding approximately 0.38 ll of separated plasma within 12 min. Without any of the requirements of sophisticated equipment or dilution techniques, we can not only separate the plasma from the whole blood for on-chip analysis but also can push out only the separated plasma to the outlet for off-chip analysis. V C 2015 AIP Publishing LLC.

Vacuum-driven power-free microfluidics utilizing the gas solubility or permeability of polydimethylsiloxane (PDMS)

“…8B). 70 In this study, manually operating syringes were employed as mobile vacuum sources, which were connected to pneumatic chambers. The separation chamber and pneumatic chambers were isolated by a thin PDMS wall.…”

Symmetric surficial phaseguides: a passive technology to generate wall-less channels by two-dimensional guiding elements

“…Phaseguides consists either of a different material (Choi et al 2015;Vulto et al 2006) or of a different geometry (Phurimsak et al 2014;Podszun et al 2012;PuchbergerEnengl et al 2014;Vulto et al 2010Vulto et al , 2011Xu et al 2015). Phaseguides based on a different material consist usually of thin stripes of SU8 (Vulto et al 2006), Teflon (Vulto et al 2006) or SiO 2 (Choi et al 2015) which are patterned on the top or bottom plate of the chip.…”

“…In order to keep the fabrication process simple, geometrical phaseguides are often made of the same material as the channel walls and or the top / bottom plate. So common materials are dry film resist like Ordyl (Puchberger-Enengl et al 2014;Vulto et al 2011), UV curable materials like SU8 and polydimethylsiloxane (PDMS) (Tung et al 2013;Xu et al 2015) or thermoplastics and thermoset materials. Here the fabrication is usually based on photolithography processes, casting or hot embossing which are compatible with other low-cost fabrication processes.…”

Acoustofluidic bacteria separation

“…With its high performance in cell manipulation, microfluidics has recently emerged as a powerful platform for cell separation. [13–16] Thus far, different microfluidic platforms have been developed for bacterial separation using affinity capture,[17] hydrodynamic force,[18] inertial force,[19,20] magnetic force,[21–26] dielectrophoretic force,[27,28] or acoustic force. [29–32] Among these bacterial separation technologies, acoustic approaches have some attractive features that make them suitable for separating pathogenic bacteria prior to detection.…”