MICROFLUIDIC STUDY ON A TRANSPARENT BLOOD MODEL FLUID WITH ALGINATE MICROSPHERES

• Published in: International journal of artificial organs 2023-07, Vol.46 (7), p.402
• Main Authors: Froese, V, Gabel, G, Parnell, J, Prause, A, Lommel, M, Kertzscher, U
• Format: Article
• Language: English
• Subjects: Alginates; Alginic acid; Blood; Body temperature; Damage; Erythrocytes; Formability; In vitro methods and tests; Medical equipment; Microchannels; Microfluidics; Microspheres; Multiphase flow; Production methods; Rheological properties; Shear; Shear thinning (liquids); Two phase flow; Viscosity; Wall flow
• ISSN: 0391-3988; 1724-6040

Objectives: The reduction of blood damage is still a big challenge in blood-carrying medical devices. In vitro experiments are performed to investigate the damage-causing effects, but due to the opaqueness of blood cells, only near-wall flows can be observed. Thus, several transparent blood models to visualize the rheologic behavior of blood have been proposed and examined. Nevertheless, two-phase blood models with added particles still represent the properties of blood inadequately or are very expensive and complex to produce. Methods: In this in vitro study, the viscosity, the flow behavior and the cell deformation of human red blood cells have been compared to a novel, easy-to-produce, two-phase blood model fluid with deformable alginate microspheres. The comparison has been performed in a cone-plate rheometer, a straight and a hyperbolic converging microchannel. Results: The viscosity of the blood model fluid with a particle fraction of 30 % shows a shear-thinning behavior, comparable to that of blood at room and human body temperature within shear rates from 7 – 1000 s-1. In high shear rates the blood model fluid reaches an almost constant value of 4.6 mPas at 22 °C and 3.7 mPas at 37 °C. The size of the alginate microspheres is 8.37 μm ±1.87 μm in diameter. They are deformable in an extensional flow with a deformation index of 0.44 ± 0.14 that is 14 % lower than the one of the red blood cells. In a straight microchannel the blood model fluid forms a cell free layer comparable to that of blood. The experiments show a good optical accessibility of the two-phase flow with traceable movements of individual microspheres in the center of the microchannel. Conclusions: With this study it could be shown that the blood model fluid is well suited to be used in experimental setups to mimic the two-phase flow behavior of blood.