A cellular cardiac matrix-based porous microcarrier as a cell delivery system in myocardial tissue engineering application

Myocardial infarction (MI) causes a high mortality rate in the world every year. Myocardial tissue engineering using extracellular matrix-derived substrate and cytocompatible biopolymers is a promising approach for treating MI. Besides, injectable porous microspheres are developing engineer constructs to use as dual-purpose microcarriers for cell culture and injectable scaffolds in trivial invasiveness for tissue implantation. This study aimed to fabricate porous microcarriers composed of myocardial extracellular matrix and chitosan using an electrospraying technique. The effect of electrospraying parameters, including extracellular matrix/chitosan ratio and voltage, on MCs diameter was evaluated and in higher voltage at 11 kV fabricated microcarriers at the range of 310–360 µm through control of extracellular matrix content at the range of 0.75–0.5%, respectively. The porosity and pore size of the MCs were manipulated from 83 to 92% and 55 to 185 µm, which is a desirable condition for molecular exchange and cellular infiltration. Density of microcarrier, using 0.66% extracellular matrix, was 1.17 g/mL which would not float in the culture medium and cells could attach uniformly. The degradation rate of composite microcarriers in higher extracellular matrix concentration of extracellular matrix was faster and solubilized more easily. The SEM, swelling measurements, and mitochondrial activity assay revealed that microcarriers with chitosan/extracellular matrix weight ratio of 3.5/0.66 could be considered as a promising candidate for injectable scaffolds supporting the attachment of cardiac progenitor cells. Graphical abstract: [Figure not available: see fulltext.]