Development, in vitro, and in vivo assessments of PCL-gelatin-βTCP fibrous scaffolds for cardiac regeneration.

Introduction: Cardiovascular disease is a leading cause of death worldwide. Tissue engineering offers a promising solution for promoting tissue regeneration at the infarcted site. In this study, beta-tricalcium phosphate (βTCP) was incorporated into poly(ε-caprolactone) (PCL) and gelatin (Gel) fibers for cardiac patch applications.

Methods: Electrospun scaffolds were prepared via electrospinning a 1:1 (w/w) mixture of PCL and Gel, embedding varying concentrations of βTCP at 0.25, 0.5, 1, and 3 wt.%. The scaffolds were analyzed through scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), tensile strength testing, hemolysis assays, toxicity testing, and quantitative reverse transcription polymerase chain reaction (qRT-PCR) for marker gene expression. Furthermore, subcutaneous scaffold implantation was performed to assess in vivo angiogenesis in NMRI mice. Tissue samples were examined using hematoxylin and eosin (H&E) staining and immunohistochemistry.

Results: According to the results, βTCP was uniformly distributed throughout the fiber scaffold, exhibiting a smooth, unbranched morphology with fiber diameters of approximately 75 μm. Specifically, the mean diameters for PCL-Gel and PCL-Gel-βTCP at 3 wt.% were 45.01 ± 2.82 μm and 100.91 ± 11.69 μm, respectively. Mechanical property assessments revealed that the elastic modulus of the scaffolds was suitable for usage as a tissue-engineered cardiac patch. Scaffolds containing βTCP exhibited favorable blood compatibility and indicated no cytotoxicity at the tested concentrations. Furthermore, the expression levels of cardiac marker genes (Actn4, Connexin43, and TrpT2) were elevated in the treatment groups in conjunction with the escalation of βTCP dosage. Fiber composites with 1% βTCP were selected as the optimal scaffold for in vivo examination. This scaffold demonstrated a significantly enhanced cell migration rate, with a growth in capillary formation observed in the immunohistochemistry analysis.

Conclusion: The fibrous PCL-Gel-βTCP-1% scaffold showed optimal cell proliferation, blood compatibility and vascularization. These properties highlight its promise for cardiac tissue engineering.