Electromechanical stimulation bioreactor for cardiac tissue engineering: optimization, development and validation test.

In tissue engineering (TE), biochemical and physical stimuli have been shown to be essential for supporting various biological processes, such as promoting cell differentiation and tissue maturation. Conventional 2D cultures using Petri dishes or flasks are static systems that do not adequately mimic the three-dimensional environment of native tissue. They fail to ensure the even distribution of oxygen and nutrients and do not provide the necessary physical stimuli. Bioreactors are culture devices designed to provide defined biochemical and physical stimuli to promote in vitro the development of biological processes under closely monitored and controlled conditions. They are therefore fundamentally important to overcome the limitations of static cell cultures and ensure process standardization. Cardiac tissue engineering (CTE) proposes innovative solutions such as the culturing and maturation of cardiac tissue samples in vitro. This approach allows for conducting drug tests or investigating pathophysiological processes in response to specific biochemical and physical stimuli. However, due to its complexity, cardiac tissue requires specific conditions and stimulation to be cultured and maintained in vitro. Notably, the combination of electrical and mechanical stimuli has yielded promising results, for instance, leading to the differentiation of hiPSC-derived cells into cardiomyocytes. This thesis aims to optimize the hardware of a previously developed bioreactor aimed at providing active electromechanical stimulation to the constructs. The main features of the native bioreactor include: the capability for parallel culture using a 12-well multiwell plate as the culture chamber; active mechanical stimulation suspended between two pillars; and electrical stimulation from a pair of electrodes in each well. Following an analysis of the initial system, this work focused on maintaining its existing strengths while addressing areas that required further development. The work primarily involved 3D modelling and editing bioreactor components in a SolidWorks environment. The optimization criteria aimed to create a modular device with simple and intuitive elements, that is easy to use and adheres to Good Laboratory Practice (GLP) standards. As a preliminary evaluation of functionality, Finite Element Analysis (FEA) was performed using SolidWorks and Comsol software. During the prototyping phase, these analyses allowed for the sizing and screening of different components version before implementation, leading to significant resource savings. The entire device was prototyped using 3D printing techniques, specifically Stereolithography (SLA) and Fused Deposition Modeling (FDM). The main result of the work is the introduction of a modular frame structure to support three constructs, combining two rigid elements mounting pillars, and two spring elements. The springs allow deformation in the direction of mechanical stimulation while providing structural support. This component significantly improves handling of the constructs and protects them from accidental damage. Tests conducted on the prototype confirmed the functionality of these components. Future developments for the prototype include producing a version using biocompatible and autoclavable materials to test its effectiveness in cell culture as well as designing a lid with integrated electrodes and control circuitry to allow combined electrical and mechanical stimulation.