Novel Dynamic Bioreactor System for Heart Valve Cultivation under Echocardiographic Control

Abstract

Dynamic bioreactor systems are widely used in heart valve tissue engineering as the means to apply defined mechanical stimuli on seeded myofibroblasts, thus promoting the development of sturdy yet elastic autologous tissue. Allowing for the delicate character of newly seeded cells as for the constant change of their mechanical properties over cultivation time, it is desirable to have a highly flexible dynamic bioreactor system adjustable to the changing demands. For this task a pulsatile bioreactor has been designed and built. This bioreactor renders possible the application of highly configurable pressure profiles on a heart valve and hence the simulation of the changing physiological environment of a growing heart valve. It consists of a pressure chamber where a PC-controlled linear actuator applies pulsatile pressure on the valve through a silicone membrane, and a reservoir chamber where several monitoring devices can be attached. Through the use of pressure sensors direct feedback to the actuator is possible and the development of the heart valve can be closely supervised. The system has been successfully tested on newly acquired porcine aortic and pulmonary valves.