Biowire II Platform: High Fidelity Heart-on-a-chip for Drug Screening and Disease Modeling

Cardiotoxicity is a major cause of drug failure at the late stages of clinical trials and it is linked to unqualified candidates as early as possible is key for reducing the costs of drug discovery and preventing the patient fatality. Tissue engineering using cardiomyocytes derived from human pluripotent stem cells holds a promise to revolutionize drug discovery, but only if limitations related to tissue maturation, cardiac chamber specification and platform versatility can be overcome. The plastic-based platform developed in this thesis, Biowire II, facilitates the scalable, miniaturized 3D tissue cultivation with multiple cell sources in a low absorption environment. The platform deploys two fluorescent, elastic polymer wires to serve as tissue anchors and force sensors, and enables on-line, non-invasive, recording of passive tension, active force, contractile dynamics, Ca2+ transients, endpoint assessments of action potentials and conduction velocity. The conditions of cardiac tissue formation, including cell seeding density, non-myocyte populations and hydrogels, were characterized in detail to ensure the consistent production of functional tissues with hallmarks of adult myocardium. The temporary electrical pacing and long-term electrical conditioning were incorporated and optimized for the platform to facilitate standardized drug testing and chamber-specific cardiac tissue maturation. By combining directed cell differentiation with electrical field conditioning, we engineered electrophysiologically distinct atrial and ventricular tissues with chamber-specific drug responses and gene expression. This study is the first to report the engineering of the heteropolar cardiac tissues, which contain well-separated atrial and ventricular ends, and demonstrate their spatially confined responses to serotonin and ranolazine. More importantly, Biowire II platform enabled modeling of polygenic left ventricular hypertrophy with induced pluripotent stem cell derived cardiomyocytes from six different patients, using uniquely designed 8-months-long electrical conditioning protocol. The platform was scaled up into a 96 well-plate format with all the key features, such as plastic culture environment, elastic force sensors and embedded carbon electrodes. An innovative fabrication method was developed to rapidly cast suspended force sensors on top of a patterned surface. This advanced version of platform eliminates adhesives, standardizes and further increases the throughput of tissue production and drug testing.Ph.D.2021-12-02 00:00:0