Strathprints Home | Open Access | Browse | Search | User area | Copyright | Help | Library Home | SUPrimo

Extensional flow of blood analogue solutions in microfluidic devices

Sousa, P.C. and Pinho, F.T. and Oliveira, Monica and Alves, M.A. (2011) Extensional flow of blood analogue solutions in microfluidic devices. Biomicrofluidics, 5 (1). ISSN 1932-1058

[img]
Preview
PDF - Published Version
Download (2236Kb) | Preview

    Abstract

    In this study, we show the importance of extensional rheology, in addition to the shear rheology, in the choice of blood analog solutions intended to be used in vitro for mimicking the microcirculatory system. For this purpose, we compare the flow of a Newtonian fluid and two well-established viscoelastic blood analog polymer solutions through microfluidic channels containing both hyperbolic and abrupt contractions/expansions. The hyperbolic shape was selected in order to impose a nearly constant strain rate at the centerline of the microchannels and achieve a quasihomogeneous and strong extensional flow often found in features of the human microcirculatory system such as stenoses. The two blood analog fluids used are aqueous solutions of a polyacrylamide 125 ppm w/w and of a xanthan gum 500 ppm w/w, which were characterized rheologically in steady-shear flow using a rotational rheometer and in extension using a capillary breakup extensional rheometer CaBER. Both blood analogs exhibit a shear-thinning behavior similar to that of whole human blood, but their relaxation times, obtained from CaBER experiments, are substantially different by one order of magnitude. Visualizations of the flow patterns using streak photography, measurements of the velocity field using microparticle image velocimetry, and pressure-drop measurements were carried out experimentally for a wide range of flow rates. The experimental results were also compared with the numerical simulations of the flow of a Newtonian fluid and a generalized Newtonian fluid with shear-thinning behavior. Our results show that the flow patterns of the two blood analog solutions are considerably different, despite their similar shear rheology. Furthermore, we demonstrate that the elastic properties of the fluid have a major impact on the flow characteristics, with the polyacrylamide solution exhibiting a much stronger elastic character. As such, these properties must be taken into account in the choice or development of analog fluids that are adequate to replicate blood behavior at the microscale.

    Item type: Article
    ID code: 41370
    Keywords: extensional flow , microfluidic devices, blood analogue fluid , Mechanical engineering and machinery
    Subjects: Technology > Mechanical engineering and machinery
    Department: Faculty of Engineering > Mechanical and Aerospace Engineering
    Technology and Innovation Centre > Advanced Engineering and Manufacturing
    Related URLs:
      Depositing user: Pure Administrator
      Date Deposited: 10 Oct 2012 10:59
      Last modified: 13 Jun 2013 09:04
      URI: http://strathprints.strath.ac.uk/id/eprint/41370

      Actions (login required)

      View Item

      Fulltext Downloads: