Patient deaths resulting from cardiovascular diseases are increasing across the globe, posing the greatest risk to patients in developed countries. Myocardial infarction, as a result of inadequate blood flow to the myocardium, results in irreversible loss of cardiomyocytes which can lead to heart failure. A sequela of myocardial infarction is scar formation that can alter the normal myocardial architecture and result in arrhythmias. Over the past decade, a myriad of tissue engineering approaches has been developed to fabricate engineered scaffolds for repairing cardiac tissue. This paper highlights the recent application of electrically conductive nanomaterials (carbon and gold-based nanomaterials, electroactive polymers) to the development of scaffolds for cardiac tissue engineering. Moreover, this work summarizes the effects of these nanomaterials on cardiac cell behavior such as proliferation and migration, as well as cardiomyogenic differentiation in stem cells.

Mimicking the structure of extracellular matrix (ECM) of myocardium is necessary for fabrication of functional cardiac tissue. The superparamagnetic iron oxide nanoparticles (SPIONs, Fe3O4), as new generation of magnetic nanoparticles (NPs), are highly intended in biomedical studies. Here, SPION NPs (1 wt%) were synthesized and incorporated into silk‐fibroin (SF) electrospun nanofibers to enhance mechanical properties and topography of the scaffolds. Then, the mouse embryonic cardiac cells (ECCs) were seeded on the scaffolds for in vitro studies. The SPION NPs were studied by scanning electron microscope (SEM), X‐ray diffraction (XRD), and transmission electron microscope (TEM). SF nanofibers were characterized after incorporation of SPIONs by SEM, TEM, water contact angle measurement, and tensile test. Furthermore, cytocompatibility of scaffolds was confirmed by 3‐(4, 5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyl tetrazolium bromide (MTT) assay. SEM images showed that ECCs attached to the scaffolds with elongated morphologies. Also, the real‐time PCR and immunostaining studies approved upregulation of cardiac functional genes in ECCs seeded on the SF/SPION‐casein scaffolds including GATA‐4, cardiac troponin T, Nkx 2.5, and alpha‐myosin heavy chain, compared with the ones in SF. In conclusion, incorporation of core‐shells in SF supports cardiac differentiation, while has no negative impact on ECCs' proliferation and self‐renewal capacity.

The graphene-based nanocomposites are considered as great candidates for enhancing electrical and mechanical properties of nonconductive scaffolds in cardiac tissue engineering. In this study, reduced graphene oxide-silver (rGO-Ag) nanocomposites(1 and 2 wt%) were synthesized and incorporated into polyurethane (PU) nanofibers via electrospinning technique. Next, the human cardiac progenitor cells (hCPCs) were seed on these scaffolds for in vitro studies. The rGO-Ag nanocomposites were studied by X-ray diffraction (XRD), Raman spectroscopy, and transmission electron microscope (TEM). After incorporation of rGO-Ag into PU nanofibers, the related characterizations were carried out including scanning electron microscope (SEM), TEM, water contact angle, and mechanical properties. Furthermore, PU and PU/nanocomposites scaffolds were used for in vitro studies, wherein hCPCs showed good cytocompatibility via 3-(4, 5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay and considerable attachment on the scaffold using SEM studies. Real-time polymerase chain reaction (PCR) and immunostaining studies confirmed the upregulation of cardiac specific genes including GATA-4, T-box 18 (TBX 18), cardiac troponin T (cTnT), and alphamyosin heavy chain (α-MHC) in the PU/rGO-Ag scaffolds in comparison with neat PU ones. Therefore, these nanofibrous rGO-Ag-reinforced PU scaffolds can be considered as suitable candidates in cardiac tissue engineering.

No abstract

No abstract

No abstract

Mimicking the extracellular matrix to have a similar nanofibrous structure regarding electrical conductivity and mechanical properties would be highly beneficial for cardiac tissue engineering. The molybdenum disulfide, MoS 2 , and reduced graphene oxide, rGO, nanosheets are two-dimensional nanomaterials which can be considered as great candidates for enhancing the electrical and mechanical properties of biological scaffolds for cardiac tissue engineering applications. In this study, MoS 2 and rGO nanosheets were synthesized and incorporated into silk fibroin nanofibers, SF, via electrospinning method. Then, the human iPSCs transfected with TBX-18 gene, TBX18-hiPSCs, were seeded on these scaffolds for in vitro studies. The MoS 2 and rGO nanosheets were studied by Raman spectroscopy. After incorporation of the nanosheets into SF nanofibers, the associated characterizations were carried out including scanning electron microscopy, transmission electron microscopy, water contact angle, and mechanical test. Furthermore, SF, SF/MoS 2 , and SF/rGO scaffolds were used for in vitro studies. Herein, the scaffolds exhibited acceptable biocompatibility and considerable attachment to TBX18-hiPSCs confirmed by 3-(4, 5dimethylthiazol-2-yl)-2, 5-diphenyl tetrazolium bromide, MTT, assay, and scanning electron microscopy. Also, the real-time PCR and immunostaining studies confirmed the maturity and upregulation of cardiac functional genes, including GATA-4, c-TnT, and α-MHC in the SF/MoS 2 and SF/rGO scaffolds compared with the bare SF one.Therefore, the reinforcement of these SF-based scaffolds with MoS 2 and rGO endues them as a suitable candidate for cardiac tissue engineering.

Mimicking the structure of extracellular matrix and electrical conductivity of myocardium are required to regenerate the functional cardiac tissue. In this study, Molybdenum disulfide, MoS2, nanosheets were synthesized and incorporated into nylon6 electrospun nanofibers in order to enhance the mechanical properties and electrical conductivity of the scaffolds. Then, the mouse embryonic cardiac cells, mECCs, were seeded on the scaffolds for in vitro studies. The MoS2 nanosheets were studied by scanning electron microscopy (SEM) and Raman spectroscopy. Nylon/MoS2 nanofibers were characterized by SEM, transmission electron microscopy (TEM), water contact angle measurement, electrical conductivity, and tensile test. Furthermore, cytocompatibility of scaffolds was confirmed by 3‐(4, 5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyl tetrazolium bromide, MTT, assay. SEM images showed more elongated morphology for mECCs attached to the nylon/MoS2 scaffold. Also, the Real‐Time PCR and immunostaining studies indicated the maturation and upregulation of cardiac functional genes including GATA‐4, c‐TnT, Nkx 2.5 and α‐MHC in the nylon/MoS2 scaffold in comparison to the bare nylon. Therefore, MoS2 reinforced nylon nanofibrous scaffolds can be considered as a suitable candidate in cardiac tissue engineering.