Magnetic super-hydrophilic carbon nanotubes/graphene oxide composite as nanocarriers of mesenchymal stem cells: Insights into the time and dose dependences

Impact of Graphene Derivatives as Artificial Extracellular Matrices on Mesenchymal Stem Cells

Thanks to stem cells' capability to differentiate into multiple cell types, damaged human tissues and organs can be rapidly well-repaired. Therefore, their applicability in the emerging field of regenerative medicine can be further expanded, serving as a promising multifunctional tool for tissue engineering, treatments for various diseases, and other biomedical applications as well. However, the differentiation and survival of the stem cells into specific lineages is crucial to be exclusively controlled. In this frame, growth factors and chemical agents are utilized to stimulate and adjust proliferation and differentiation of the stem cells, although challenges related with degradation, side effects, and high cost should be overcome. Owing to their unique physicochemical and biological properties, graphene-based nanomaterials have been widely used as scaffolds to manipulate stem cell growth and differentiation potential. Herein, we provide the most recent research progress in mesenchymal stem cells (MSCs) growth, differentiation and function utilizing graphene derivatives as extracellular scaffolds. The interaction of graphene derivatives in human and rat MSCs has been also evaluated. Graphene-based nanomaterials are biocompatible, exhibiting a great potential applicability in stem-cell-mediated regenerative medicine as they may promote the behaviour control of the stem cells. Finally, the challenges, prospects and future trends in the field are discussed.

A Mini Review: Application Progress of Magnetic Graphene Three-Dimensional Materials for Water Purification

Marine oil pollution, colored counterattacks, and heavy metal ions in the water will cause serious environmental problems and threaten human health. The three-dimensional material prepared by graphene, as a new nanomaterial, has a large specific surface area and surface chemical activity. Various impurities in the water can be absorbed, which is very suitable as a water purification material. Depositing Fe₃O₄ and other magnetic materials on graphene three-dimensional materials can not only increase recyclability but increase hydrophobicity. Therefore, magnetic graphene three-dimensional materials have a high potential for use in water purification. This article reviews the research progress and adsorption mechanism of magnetic graphene materials for water purification. Finally, the future research prospects of magnetic graphene materials have prospected.

High loads of nano-hydroxyapatite/graphene nanoribbon composites guided bone regeneration using an osteoporotic animal model

BACKGROUND

It has been difficult to find bioactive compounds that can optimize bone repair therapy and adequate osseointegration for people with osteoporosis. The nano-hydroxyapatite (nHAp)/carbon nanotubes with graphene oxides, termed graphene nanoribbons (GNR) composites have emerged as promising materials/scaffolds for bone regeneration due to their bioactivity and osseointegration properties. Herein, we evaluated the action of nHAp/GNR composites (nHAp/GNR) to promote bone regeneration using an osteoporotic model.

MATERIALS AND METHODS

First, three different nHAp/GNR (1, 2, and 3 wt% of GNR) were produced and characterized. For in vivo analyses, 36 Wistar rats (var. albinus, weighing 250-300 g, Comissão de Ética no Uso de Animais [CEUA] n.002/17) were used. Prior to implantation, osteoporosis was induced by oophorectomy in female rats. After 45 days, a tibial fracture was inflicted using a 3.0-mm Quest trephine drill. Then, the animals were separated into six sample groups at two different time periods of 21 and 45 days. The lesions were filled with 3 mg of one of the above samples using a curette. After 21 or 45 days of implantation, the animals were euthanized for analysis. Histological, biochemical, and radiographic analyses (DIGORA method) were performed. The data were evaluated through ANOVA, Tukey test, and Kolmogorov-Smirnov test with statistical significance at P<0.05.

RESULTS

Both nHAp and GNR exhibited osteoconductive activity. However, the nHAp/GNR exhibited regenerative activity proportional to their concentration, following the order of 3% >2% >1% wt.

CONCLUSION

Therefore, it can be inferred that all analyzed nanoparticles promoted bone regeneration in osteoporotic rats independent of analyzed time.