Biomimetic Construction And Functional Study Of Three-demensional Cardiac Tissue In Vitro

The in vitro Tissue Engineering Model is an important research method in the medical research.Cardiovascular disease is the one with the highest prevalence rate.How to develop an in vitro three-dimensional cardiac tissue model with natural structure and function is a hot spot in the field of tissue engineering.The anisotropic and oriented structure of cardiac tissue is compatible with the pumping function of the heart.Many designs have successfully guided the cellular alignment,but few to individually control the 3D multi-layers orientation and achieve sufficient contact of the cells between layers.Based on the biomimetic design principle and the “Basic Element Construction” strategy in tissue engineering,a novel design of the biomimetic 3D cardiac tissue model was presented.Multi-layer myocardial cells grown on aligned fiber films are encapsulated with hydrogel.The scientific and technological issues about the design,construction,and application of the 3D models were studied systematically.Above all,the main work includes the material and structural design of the 3D multilayer structures;developing a simple device to fabricate aligned fiber films with features such as highly oriented,uniform diameter,and ultra-thin;improving Gel MA hydrogel structure,leading to high elasticity and shape memory properties;conducting cell experiment for the characterization and evaluation of the biocompatibility and 3D structure of the constructs;applying the self-developed process to the construction of 3D cardiac tissue,and assessed the maturation and beating function of it.The 3D culture of neonatal cardiomyocytes from SD rats displayed the orientation and elongation in the direction of each film,forming a multi-layer tissue with a layer spacing of60μm.The 3D myocardial tissue started spontaneously and synchronously contraction within48 hours.The beating frequency is 1.5～2Hz,and the maximum contraction velocity can reach7000μm/s.Video analysis of the contraction of aligned single-layer and multi-directional threelayer(0°-45°-90°)tissues found that the single-layer oriented myocardium contracted in one direction.The three-layer tissue also beat synchronized,but the contract direction of it has a composition effect by multilayers,resulting in centripetal contraction,which is a similar function with the natural myocardium: shortening simultaneously in all directions.