Injectable gellan/gelatin microspheres for the treatment of heart failure

Injectable scaffolds are receiving a great interest as strategies to repair the infarcted myocardium. The aim of this work was the preparation and characterization of injectable microspheres for myocardial tissue engineering. Gellan/gelatin microspheres were prepared by a single water-in oil emulsion, using phosphatidylcholine as surfactant. The obtained particles underwent morphological, physicochemical and functional investigation. Loading with IGF-1 was then performed by adsorption. Loaded and unloaded particles, in combination with rat cardiac progenitor cells, were injected after cryoinjury on the rat heart. The morphological analysis showed a spherical shape and microporous surface. The infrared analysis confirmed the presence of interactions among the functional groups of the two biopolymers. Injectability through a narrow needle was verified. Preliminary in vivo tests, performed by three intramyocardial injections of cell loaded microspheres in a rat model of myocardial injury, documented that progenitor cells homed to the damaged myocardium and IGF-1 functionalization increased their engraftment. The results obtained showed adequate morphological, physicochemical, functional and biological properties for application as injectable scaffold for myocardial repair. This work was supported by the European Commission FP7 Programme, grant 214539

Bioactive Electrospun Fibers of Poly(glycerol sebacate) and Poly(ε-caprolactone) for Cardiac Patch Application

Scaffolds for cardiac patch application must meet stringent requirements such as biocompatibility, biodegradability, and facilitate vascularization in the engineered tissue. Here, a bioactive, biocompatible, and biodegradable electrospun scaffold of poly(glycerol sebacate)-poly(ε-caprolactone) (PGS-PCL) is proposed as a potential scaffold for cardiac patch application. The fibers are smooth bead free with average diameter = 0.8 ± 0.3 μm, mean pore size = 2.2 ± 1.2 μm, porosity = 62 ± 4%, and permeability higher than that of control biological tissue. For the first time, bioactive PGS-PCL fibers functionalized with vascular endothelial growth factor (VEGF) are developed, the approach used being chemical modification of the PGS-PCL fibers followed by subsequent binding of VEGF via amide bonding. The approach results in uniform immobilization of VEGF on the fibers; the concentrations are 1.0 μg cm-2 for the PGS-PCL (H) and 0.60 μg cm-2 for the PGS-PCL (L) samples. The bioactive scaffold supports the attachment and growth of seeded myogenic and vasculogenic cell lines. In fact, rat aortic endothelial cells also display angiogenic features indicating potential for the formation of vascular tree in the scaffold. These results therefore demonstrate the prospects of VEGF-functionalized PGS-PCL fibrous scaffold as promising matrix for cardiac patch application