Generation of Blood Analogs to Mimic Its Non-Newtonian Shear-thinning Characteristics

Blood analogs are often employed in in-vitro simulations for the pathophysiological diagnosis of neurovascular and cardiovascular diseases such as aneurysms and stenosis, as well as pre-surgical planning and intraoperative orientation to help physicians with surgical procedures. Thus, to obtain accurate information on blood-associated parameters such as wall shear stress and relative residence time which are pivotal for the following diagnosis and therapeutics, the employed blood analogs should own realistic physical properties such as non-Newtonian shear-thinning in in-vitro experiments. In this study, two types (i.e., Type-I and Type-II) of blood analogs were generated under the designated temperature in the range of 292-315K. Type-I is for general use only consisting of deionized (DI) water and Xanthan gum (XG) power, and Type-II is used for particle image velocimetry (PIV) experiments which require transparent blood equivalent, as a mixture of DI water, XG power, and fluorescent red polyethylene microspheres (10~45 um). The viscosities of blood analogs with corresponding formula under varying shear rates used an IKA Rotavisc lo-vi viscometer under an isothermal environment (T= 293.15 K). The results were compared to our previous in-vivo data for validation. It found that both types of blood analogs with corresponding formulas successfully simulate the shear-thinning properties of blood with an overall relative difference of less than 5%. In addition, it was observed that there is a strong linear relationship between body temperature and XG concentration of blood analogs for both analogs, namely, 292-312 K vs. 140-600 ppm for Type-I and 292-315 K vs. 140-600 ppm for Type-II, respectively. Future studies include using alternative materials such as polysaccharide particles to mimic blood cells for more realistic blood analog generation to investigate the associated hemodynamic behaviors on the pathophysiology of neurovascular and cardiovascular diseases.