Graphene-based materials enhance cardiomyogenic and angiogenic differentiation capacity of human mesenchymal stem cells in vitro - Focus on cardiac tissue regeneration.

Cell-based therapies have recently emerged as promising strategies for the treatment of cardiovascular disease. Mesenchymal stem cells (MSCs) are a promising cell type that represent a class of adult stem cells characterized by multipotency, high proliferative capacity, paracrine activity, and low immunogenicity. To improve the functional and therapeutic efficacy of MSCs, novel biomaterials are considered as scaffolds/surfaces that promote MSCs growth and differentiation. One of them are graphene-based materials, including graphene oxide (GO) and reduced graphene oxide (rGO). Due to the unique physical, chemical, and biological properties of graphene, scaffolds comprising GO/rGO have been examined as novel platforms to improve the differentiation potential of human MSCs in vitro. We verified different i) size of GO flakes, ii) reduction level, and iii) layer thickness to select the most suitable artificial niche for MSCs culture. The results revealed that graphene-based substrates constitute non-toxic substrates for MSCs. Surfaces with large flakes of GO as well as low reduced rGO are the most biocompatible for MSCs propagation and do not affect their proliferation and survival. Interestingly, small GO flakes and highly reduced rGO decreased MSCs proliferation and induced their apoptosis. We also found that GO and rGO substrates did not alter the MSCs phenotype, cell cycle progression and might modulate the adhesive capabilities of these cells. Importantly, we demonstrated that both materials promoted the cardiomyogenic and angiogenic differentiation capacity of MSCs in vitro. Thus, our data indicates that graphene-based surfaces represent promising materials that may influence the therapeutic application of MSCs via supporting their pro-regenerative potential.

Impact of Graphene-Based Surfaces on the Basic Biological Properties of Human Umbilical Cord Mesenchymal Stem Cells: Implications for Ex Vivo Cell Expansion Aimed at Tissue Repair.

The potential therapeutic applications of mesenchymal stem/stromal cells (MSCs) and biomaterials have attracted a great amount of interest in the field of biomedical engineering. MSCs are multipotent adult stem cells characterized as cells with specific features, e.g., high differentiation potential, low immunogenicity, immunomodulatory properties, and efficient in vitro expansion ability. Human umbilical cord Wharton's jelly-derived MSCs (hUC-MSCs) are a new, important cell type that may be used for therapeutic purposes, i.e., for autologous and allogeneic transplantations. To improve the therapeutic efficiency of hUC-MSCs, novel biomaterials have been considered for use as scaffolds dedicated to the propagation and differentiation of these cells. Nowadays, some of the most promising materials for tissue engineering include graphene and its derivatives such as graphene oxide (GO) and reduced graphene oxide (rGO). Due to their physicochemical properties, they can be easily modified with biomolecules, which enable their interaction with different types of cells, including MSCs. In this study, we demonstrate the impact of graphene-based substrates (GO, rGO) on the biological properties of hUC-MSCs. The size of the GO flakes and the reduction level of GO have been considered as important factors determining the most favorable surface for hUC-MSCs growth. The obtained results revealed that GO and rGO are suitable scaffolds for hUC-MSCs. hUC-MSCs cultured on: (i) a thin layer of GO and (ii) an rGO surface with a low reduction level demonstrated a viability and proliferation rate comparable to those estimated under standard culture conditions. Interestingly, cell culture on a highly reduced GO substrate resulted in a decreased hUC-MSCs proliferation rate and induced cell apoptosis. Moreover, our analysis demonstrated that hUC-MSCs cultured on all the tested GO and rGO scaffolds showed no alterations of their typical mesenchymal phenotype, regardless of the reduction level and size of the GO flakes. Thus, GO scaffolds and rGO scaffolds with a low reduction level exhibit potential applicability as novel, safe, and biocompatible materials for utilization in regenerative medicine.