High-speed microfluidic differential manometer for cellular-scale hydrodynamics

Division of Engineering and Applied Sciences, Harvard University, Pierce Hall, Cambridge, MA 02138, USA.
Proceedings of the National Academy of Sciences (Impact Factor: 9.81). 02/2006; 103(3):538-42. DOI: 10.1073/pnas.0507171102
Source: PubMed

ABSTRACT We propose a broadly applicable high-speed microfluidic approach for measuring dynamical pressure-drop variations along a micrometer-sized channel and illustrate the potential of the technique by presenting measurements of the additional pressure drop produced at the scale of individual flowing cells. The influence of drug-modified mechanical properties of the cell membrane is shown. Finally, single hemolysis events during flow are recorded simultaneously with the critical pressure drop for the rupture of the membrane. This scale-independent measurement approach can be applied to any dynamical process or event that changes the hydrodynamic resistance of micro- or nanochannels.

Download full-text


Available from: Magalie M. Faivre, Jul 02, 2015
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: A common indicator of rheological dysfunction is a measurable decrease in the deformability of red blood cells (RBCs). Decreased RBC deformability is associated with cellular stress or pathology and can impede the transit of these cells through the microvasculature, where RBCs play a central role in the oxygenation of tissues. Therefore, RBC deformability has been recognized as a sensitive biomarker for rheological disease. In the current study, we present a strategy to measure RBC cortical tension as an indicator of RBC deformability based on the critical pressure required for RBC transit through microscale funnel constrictions. By modeling RBCs as a Newtonian liquid drop, we were able to discriminate cells fixed with glutaraldehyde concentrations that vary as little as 0.001%. When RBCs were sampled from healthy donors on different days, the RBC cortical tension was found to be highly reproducible. Inter-individual variability was similarly reproducible, showing only slightly greater variability, which might reflect biological differences between normal individuals. Both the sensitivity and reproducibility of cortical tension, as an indicator of RBC deformability, make it well-suited for biological and clinical analysis of RBC microrheology.
    Journal of Biomechanics 04/2014; 47(8). DOI:10.1016/j.jbiomech.2014.03.038 · 2.50 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The dynamics of fluid–fluid interfaces are important in diverse problems that span many disciplines in science and engineering. A series of snapshots is used to illustrate the breadth of applications that can occur in viscous low-Reynolds-number flows and I highlight theoretical and modelling ideas that are broadly useful for these, as well as other, problems. By way of illustration of unifying quantitative ideas we discuss briefly (i) the use of the Reciprocal Theorem in low-Reynolds-number flows, (ii) the use of the lubrication approximation for characterizing thin-film coating flows sometimes referred to as Landau–Levich–Derjaguin–Bretherton problems and (iii) nearly two-dimensional viscously dominated flows.
    Journal of Fluid Mechanics 02/2010; 645:1 - 25. DOI:10.1017/S0022112009994186 · 2.29 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The flow properties of blood in the microcirculation depend strongly on the hematocrit (Hct), microvessel geometry, and cell properties. Previous in vitro studies have measured the radial displacement of red blood cells (RBCs) at concentrated suspensions using conventional microscopes. However, to measure the RBCs motion they used transparent suspensions of ghost red cells, which may have different physical properties than normal RBCs. The present study introduces a new approach (confocal micro-PTV) to measure the motion of labeled RBCs flowing in concentrated suspensions of normal RBCs. The ability of confocal systems to obtain thin in-focus planes allowed us to measure the radial position of individual RBCs accurately and to consequently measure the interaction between multiple labeled RBCs. All the measurements were performed in the center plane of both 50 and 100 microm glass capillaries at Reynolds numbers (Re) from 0.003 to 0.005 using Hcts from 2% to 35%. To quantify the motion and interaction of multiple RBCs, we used the RBC radial dispersion (D(yy)). Our results clearly demonstrate that D(yy) strongly depends on the Hct. The RBCs exhibited higher D(yy) at radial positions between 0.4 and 0.8R and lower D(yy) at locations adjacent to the wall (0.8-1R) and around the middle of the capillary (0-0.2R). The present work also demonstrates that D(yy) tends to decrease with a decrease in the diameter. The information provided by this study not only complements previous investigations on microhemorheology of both dilute and concentrated suspensions of RBCs, but also shows the influence of both Hct and geometry on the radial dispersion of RBCs. This information is important for a better understanding of blood mass transport mechanisms under both physiological and pathological conditions.
    Journal of Biomechanics 08/2008; 41(10):2188-96. DOI:10.1016/j.jbiomech.2008.04.033 · 2.50 Impact Factor