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 (GelMA) 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 GelMA-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 β-1 confirmed improved cell-matrix interaction on the hybrid
hydrogels. Notably, homogeneous distribution of cardiac specific markers (sarcomeric α-
actinin and
connexin 43), were observed on GelMA-GNR
hydrogels as a function of GNRs concentration. Furthermore, the GelMA-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 GelMA-GNR
hydrogels as compared to pure GelMA. Thus, the findings of this study clearly demonstrated that functional cardiac patches with superior electrical and mechanical properties can be developed using nanoengineered GelMA-GNR hybrid
hydrogels.
STATEMENT OF SIGNIFICANCE: In this work, we developed
gold nanorod (GNR) incorporated
gelatin-based
hydrogels with suitable electrical conductivity and mechanical stiffness for engineering functional cardiac tissue constructs (e.g. cardiac patches). The synthesized conductive hybrid
hydrogels properly accommodated cardiac cells and subsequently resulted in excellent cell retention, spreading, homogeneous distribution of cardiac specific markers, cell-cell coupling as well as robust synchronized (tissue-level) beating behavior.