(287i) Comsol Multiphysics Modeling and Simulation of Dielectrophoretic Biotransport for High-Throughput Sorting of Tenogenically Differentiating Mesenchymal Stem Cells

Mesenchymal stem cell (MSC)-based regenerative therapies are promising for healing tendon injuries and tears, due to their potential to differentiate into tenogenic cells. This is due stem cells’ unique self-renewal and differentiation capacities, which are advantageous for regenerative medicine and tissue engineering applications. However, generating homogeneous populations of tenogenically differentiated stem cells remains a big challenge, as non-differentiated cells can lead to post-transplantation complications. Therefore, a homogenous sample of tenogenically differentiated MSCs is critical for advancing tendon therapies and avoiding uncontrolled cell growth or non-tendon tissue formation (e.g., ectopic bone). We focused on designing and simulating a dielectrophoresis (DEP)-based label-free, microfluidic platform to sort and enrich tenogenically differentiated MSCs from undifferentiated MSCs. This study investigates the label-free microfluidic platform designed to selectively separate tenogenically differentiated MSCs from undifferentiated MSCs.

We are using the quantified dielectric signatures of differentiating tenogenic and non-tenogenic MSCs on the third day of differentiation using dielectrophoresis (DEP)—an electrokinetic method that uses nonuniform fields—reported in our preliminary study, which focused on their crossover frequencies, the frequencies at which the net DEP forces acting on the cells are zero. Here, we further estimated that the values for membrane capacitance, conductivity, and permittivity after 3-day treatment of undifferentiated cells to yield differentiated tenogenic MSCs are 2.46±0.1 pF, 0.82±0.01 S/m, and 1.97±0.05, respectively, and cytoplasm conductivity is 0.82±0.02 S/m. The estimated properties from the dielectrophoretic characterization are crucial in designing a DEP-based enrichment microdevice to collect homogeneous differentiated mesenchymal stem cell populations, i.e., tenocytes for tendon repair. Using particle tracing, creeping flow (transport of diluted species model), and electric current physics in the COMSOL Multiphysics simulation software package, we simulated the separation process within a two-stage microfluidic device operating at a sorting frequency of 160 kHz. The simulation results show that optimal separation efficiency and purity are achieved at an inlet velocity of 400 - 1000 µm/s, with specific voltage configurations, enabling recovery of one million t-differentiated MSCs in approximately 3 hours. Our results show a near-linear relationship between recovery time and particle count at the outlet boundaries and selected surfaces, indicating consistent throughput across varying conditions. This study demonstrates that DEP can offer a scalable, efficient, and label-free method for enriching MSC populations with high selectivity, enhancing more prospects for MSC-based tendon therapies and advancing the development of microfluidic sorting devices for regenerative medicine applications.

Biomaterials: Graduate Student Award Session (Invited Talks)
I kindly request that my abstract be considered for this prestigious award. Our preliminary results from this study have been published in a high-impact journal, and we are currently in the advanced stages of the research.