Microfluidic Adaptation of Density-Gradient Centrifugation for Isolation of Particles and Cells

• Published in: Bioengineering (Basel) Vol. 4; no. 3; p. 67
• Main Authors: Sun, Yuxi, Sethu, Palaniappan
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 02.08.2017; MDPI
• Subjects: Adaptation; Beads; Binary mixtures; Bioengineering; Blood; cell separations; Centrifugal force; Centrifugal pumps; Centrifugation; Density; density-gradient centrifugation; Efficiency; Fluids; Fractionation; Granulocytes; Immunoassay; label-free cell separation; microfluidics; Plasma; Polystyrene; Polystyrene resins; Reynolds number; Separation; Silicon dioxide; United States > US; cell separations; label-free cell separation; density-gradient centrifugation; microfluidics
• ISSN: 2306-5354; 2306-5354
• DOI: 10.3390/bioengineering4030067

Density-gradient centrifugation is a label-free approach that has been extensively used for cell separations. Though elegant, this process is time-consuming (>30 min), subjects cells to high levels of stress (>350 g) and relies on user skill to enable fractionation of cells that layer as a narrow band between the density-gradient medium and platelet-rich plasma. We hypothesized that microfluidic adaptation of this technique could transform this process into a rapid fractionation approach where samples are separated in a continuous fashion while being exposed to lower levels of stress (<100 g) for shorter durations of time (<3 min). To demonstrate proof-of-concept, we designed a microfluidic density-gradient centrifugation device and constructed a setup to introduce samples and medium like Ficoll in a continuous, pump-less fashion where cells and particles can be exposed to centrifugal force and separated via different outlets. Proof-of-concept studies using binary mixtures of low-density polystyrene beads (1.02 g/cm3) and high-density silicon dioxide beads (2.2 g/cm3) with Ficoll–Paque (1.06 g/cm3) show that separation is indeed feasible with >99% separation efficiency suggesting that this approach can be further adapted for separation of cells.