Mechanical Engineering Department, Worcester Polytechnic Institute, Worcester, MA, 01609, USA.
Center for Engineering in Medicine, Massachusetts General Hospital, Harvard Medical School and Shriners Hospitals for Children, Boston, MA, 02114, USA.
Sci Rep. 2021 Jan 29;11(1):2642. doi: 10.1038/s41598-021-82171-x.
Aggregation of human red blood cells (RBC) is central to various pathological conditions from bacterial infections to cancer. When left at low shear conditions or at hemostasis, RBCs form aggregates, which resemble stacks of coins, known as 'rouleaux'. We experimentally examined the interfacial dielectric dispersion of aggregating RBCs. Hetastarch, an RBC aggregation agent, is used to mimic conditions leading to aggregation. Hetastrach concentration is incrementally increased in blood from healthy donors to measure the sensitivity of the technique. Time lapse electrical impedance measurements were conducted as red blood cells form rouleaux and sediment in a PDMS chamber. Theoretical modeling was used for obtaining complex permittivity of an effective single red blood cell aggregate at various concentrations of hetastarch. Time response of red blood cells' impedance was also studied to parametrize the time evolution of impedance data. Single aggregate permittivity at the onset of aggregation, evolution of interfacial dispersion parameters, and sedimentation kinetics allowed us to distinguish differential aggregation in blood.
人红细胞（RBC）的聚集是各种病理状况的核心，从细菌感染到癌症。当处于低切变条件或止血状态时，RBC 会形成类似于硬币堆积的聚集物，称为“缗钱状”。我们通过实验研究了聚集 RBC 的界面介电色散。人血代用品羟乙基淀粉（hetastarch）被用作模拟导致聚集的条件。从健康供体的血液中逐步增加 hetastarch 的浓度，以测量该技术的灵敏度。当红细胞在 PDMS 腔中形成缗钱状并沉淀时，进行了时滞阻抗测量。理论模型用于在不同的 hetastarch 浓度下获得有效单个 RBC 聚集物的复介电常数。还研究了红细胞阻抗的时间响应，以参数化阻抗数据的时间演化。在聚集开始时的单个聚集体介电常数、界面弥散参数的演化以及沉淀动力学使我们能够区分血液中的差异聚集。
