Gold nanorod-incorporated gelatin-based conductive hydrogels for engineering cardiac tissue constructs

The development of advanced biomaterials is a crucial step to enhance the efficacy of tissue engineering strategies for treatment of myocardial infarction. Specific characteristics of biomaterials including electrical conductivity, mechanical robustness and structural integrity need to be further enhanced to promote the functionalities of cardiac cells. In this work, we fabricated UV-crosslinkable gold nanorod (GNR)-incorporated gelatin methacrylate (GeIMA) hybrid hydrogels with enhanced material and biological properties for cardiac tissue engineering. Embedded GNRs promoted electrical conductivity and mechanical stiffness of the hydrogel matrix. Cardiomyocytes seeded on GeIMA-GNR hybrid hydrogels exhibited excellent cell retention, viability, and metabolic activity. The increased cell adhesion resulted in abundance of locally organized F-actin fibers, leading to the formation of an integrated tissue layer on the GNR-embedded hydrogels. Immunostained images of integrin beta-1 confirmed improved cell matrix interaction on the hybrid hydrogels. Notably, homogeneous distribution of cardiac specific markers (sarcomeric alpha-actinin and connexin 43), were observed on GeIMA-GNR hydrogels as a function of GNRs concentration. Furthermore, the GeIMA-GNR hybrids supported synchronous tissue-level beating of cardiomyocytes. Similar observations were also noted by, calcium transient assay that demonstrated the rhythmic contraction of the cardiomyocytes on GeIMA-GNR hydrogels as compared to pure GeIMA. Thus, the findings of this study clearly demonstrated that functional cardiac patches with superior electrical and mechanical properties can be developed using nanoengineered GeIMA-GNR hybrid hydrogels.