Bio-inspired soft robotic system for reproducing myocardial biomechanics

In-vitro models of cardiovascular biomechanics/hemodynamics have emerged as a stable, controllable testbed for research into cardiac (dys)function, the development of mechanical circulatory support (MCS) devices, and the development of surgical devices and training. In recent years, researchers have turned to copying the myocardial architecture of the human heart to create biomimetic in-vitro models. Great progress has been made, but no existing model can accurately replicate the complex motions of the heart due to oversimplifications and choice of actuation. This thesis introduces a new framework for the use of soft robotic artificial muscles in physical cardiac simulators that faithfully recapitulate cardiac motion and hemodynamics in both health and disease. The feasibility of using inverse hydraulic artificial muscles in the development of a soft robotic fluid pump is first demonstrated, before developing a fabrication process that allows these muscle fibers to be arranged in close agreement to the myocardial architecture of the left ventricle. The biomimetic structure of the model is demonstrated to facilitate replication of the motions of the four phases of the cardiac cycle. A closed-loop control system was then developed to modulate the effective stiffness of the artificial ventricle, allowing for the simulation of heart failure with preserved ejection fraction (HFpEF) with the addition of a muscularized left atrium. Support of the diseased left heart is also demonstrated with a left ventricular assist device. Finally, this thesis then details the design and integration of a left-heart endocardial membrane, with functioning mitral and aortic valves, into the ventricular musculature. The membrane is fabricated using 3D printed molds and can be programmed for patient/disease specific internal cardiac geometry. With control over the papillary muscles in the mitral valve apparatus, variable mitral valve dysfunction can be induced and analyzed using clinical echocardiographic techniques. This left heart simulator is then demonstrated as a testbed for the development of a minimally invasive soft robotic catheter and its control system. This high-fidelity cardiac simulator, and those that follow, offer a stable, controllable platform for investigations into cardiac disease and the devices and tools that are used for treatment, reducing reliance on animal models, and improving outcomes in humans.