Myocardial tissue regeneration following a heart attack remains one of the fundamental challenges in the field of cardiac tissue engineering. The development of bioinspired platform that can closely mimic the native extracellular matrix (ECM) is crucial for promoting effective tissue repair. Polyurethane, due to its favorable mechanical properties, flexibility, an‎d biocompatibility, is widely regarded as a promising base polymer for such systems. In this study, a multifunctional chain extender containing unsaturated groups was synthesized via the Baylis–Hillman reaction to enable post-polymerization chemical modifications. This structure provided a suitable platform for efficient post-polymerization reactions. For this purpose, the thiol–ene click reaction, known for its rapid kinetics, high yield, an‎d lack of side products, was employed. Gelatin modified with thiobutyrolactone was used as the thiol-containing compound an‎d was covalently attached to the hard segments of the polyurethane. The incorporation of gelatin into the hard domains of polyurethane introduces synergistic effects through bioactive an‎d structural interactions, thereby enhancing the potential of the scaffold as a functional platform for myocardial tissue repair. The successful synthesis of the chain extender an‎d formation of the polyurethane hard segment were confirmed by attenuated total reflectance–Fourier transform infrared (ATR-FTIR) spectroscopy an‎d proton nuclear magnetic resonance (1H NMR) spectroscopy. Mechanical analysis of the optimized films showed a Young’s modulus in the range of 0.2 to 0.45 MPa. Dynamic mechanical thermal analysis (DMTA) further confirmed elastomeric behavior, high flexibility, an‎d a negative glass transition temperature. In vitro degradation studies revealed that samples containing 70 wt.% hard segment content experienced a 15% weight loss after one month, indicating a controlled degradation rate. Contact angle measurements demonstrated that increasing the gelatin content to 3 wt.% an‎d 6 wt.% reduced the surface contact angle from 86° (pure polyurethane) to 83° an‎d 61°, respectively, indicating enhanced surface hydro‎philicity. Cell viability assessed via the MTT assay confirmed the absence of cytotoxic effects an‎d highlighted good biocompatibility of the developed films. Cardiac-specific gene expression including GATA4, TroponinT, α-SMA, an‎d Connexin43 was eva‎luated through quantitative PCR (qPCR) an‎d immunocytochemistry. Results showed significantly higher expression levels in all samples compared to the control group. Collectively, these findings suggest that the developed platform, owing to its favorable mechanical, degradative, an‎d biological properties, holds strong potential for applications in cardiac tissue engineering.

محمد ديناري , طيبه بهزاد

افسانه فخار , عليرضا نجفي چرمهيني , سعيد كرباسي