Effects of Polyacrylonitrile/MoS₂ Composite Nanofibers on the Growth Behavior of Bone Marrow Mesenchymal Stem Cells

In recent years, molybdenum disulfide (MoS₂) as a typical class of two-dimensional (2D) materials has attracted wide attention because of its various fascinating properties. In this study, we fabricated MoS₂ composite nanofibers by electrospinning technology combined with a doping method. The as-prepared MoS₂ composite nanofibers exhibited excellent biocompatibility. In addition, the detailed investigation about the response of MoS₂ composite nanofibers on bone marrow mesenchymal stem cells (BMSCs) indicated that the obtained MoS₂ composite nanofibers could promote BMSC growth behavior, improve BMSC contact with each other, maintain cellular activity, and also provide positive promotion to regulate cellular proliferation. Moreover, the alkaline phosphatase expression significantly increased with increasing MoS₂ concentration. Compared with the excellent biocompatibility and natural extracellular-matrix-like structure, we believe that the MoS₂ composite nanofibers could provide new insight for the preparation of well-defined MoS₂ nanostructure materials and will have promising potential in biomedical applications, such as tissue engineering, photothermal therapy, etc

Fabrication, Characterization, and Biocompatibility of Polymer Cored Reduced Graphene Oxide Nanofibers

Graphene nanofibers have shown a promising potential across a wide spectrum of areas, including biology, energy, and the environment. However, fabrication of graphene nanofibers remains a challenging issue due to the broad size distribution and extremely poor solubility of graphene. Herein, we report a facile yet efficient approach for fabricating a novel class of polymer core-reduced graphene oxide shell nanofiber mat (RGO–CSNFM) by direct heat-driven self-assembly of graphene oxide sheets onto the surface of electrospun polymeric nanofibers without any requirement of surface treatment. Thus-prepared RGO–CSNFM demonstrated excellent mechanical, electrical, and biocompatible properties. RGO–CSNFM also promoted a higher cell anchorage and proliferation of human bone marrow mesenchymal stem cells (hMSCs) compared to the free-standing RGO film without the nanoscale fibrous structure. Further, cell viability of hMSCs was comparable to that on the tissue culture plates (TCPs) with a distinctive healthy morphology, indicating that the nanoscale fibrous architecture plays a critically constructive role in supporting cellular activities. In addition, the RGO–CSNFM exhibited excellent electrical conductivity, making them an ideal candidate for conductive cell culture, biosensing, and tissue engineering applications. These findings could provide a new benchmark for preparing well-defined graphene-based nanomaterial configurations and interfaces for biomedical applications

Effect of MDS-MSC on T cell apoptosis.

<p>T cells were incubated for 3 days alone or with MDS-MSC or normal-MSC in the presence of the mitogen PHA.The test was conducted by Annexin-V and PI double staining and analyzed by flow cytometry. Data are expressed as mean±SD of triplicates of 5 separate experiments. Annexin V+ means the cells were PI negative and Annexin V positive. *P≤0.05.</p

Biocompatible, Free-Standing Film Composed of Bacterial Cellulose Nanofibers–Graphene Composite

In recent years, graphene films have been used in a series of wide applications in the biomedical area, because of several advantageous characteristics. Currently, these films are derived from graphene oxide (GO) via chemical or physical reduction methods, which results in a significant decrease in surface hydrophilicity, although the electrical property could be greatly improved, because of the reduction process. Hence, the comprehensive performance of the graphene films showed practical limitations in the biomedical field, because of incompatibility of highly hydrophobic surfaces to support cell adhesion and growth. In this work, we present a novel fabrication of bacterial cellulose nanofibers/reduced graphene oxide (BC-RGO) film, using a bacterial reduction method. Thus-prepared BC-RGO films maintained excellent hydrophilicity, while electrical properties were improved by bacterial reduction of GO films in culture. Human marrow mesenchymal stem cells (hMSCs) cultured on these surfaces showed improved cellular response with higher cell proliferation on the BC-RGO film, compared to free-standing reduced graphene oxide film without the nanoscale fibrous structure. Furthermore, the cellular adhesion and proliferation were even comparable to that on the tissue culture plate, indicating that the bacterial cellulose nanofibers play a critically contructive role in supporting cellular activities. The novel fabrication method greatly enhanced the biochemical activity of the cells on the surface, which could aid in realizing several potential applications of graphene film in biomedical area, such as tissue engineering, bacterial devices, etc

Rectangle versus Square Oxalate-Connective Tetralanthanide Cluster Anchored in Lacunary Lindqvist Isopolytungstates: Syntheses, Structures, and Properties

Two types of unique oxalate-connective lanthanide-substituted isopolyoxotungstates, Na₁₀[Ln₂(C₂O₄)­(H₂O)₄(OH)­W₄O₁₆]₂·30H₂O (<b>1</b>) and K₄Na₁₆[Ln­(C₂O₄)­W₅O₁₈]₄·60H₂O (<b>2</b>) (Ln = Eu^III, Ho^III, Er^III, or Tb^III), have been synthesized under conventional aqueous solution conditions and structurally characterized by elemental analyses, IR spectra, single-crystal X-ray diffraction, and thermogravimetric analyses. It should be pointed out that the utilization of different alkaline cations leads to the formation of two structural types. When only Na⁺ ions are present in the system, type <b>1</b> was obtained, while when Na⁺ and K⁺ ions are used, type <b>2</b> was found. Complex <b>1</b> is a double-oxalate-bridging di-Ln substituted Lindqvist dimer with a rectangle tetra-Ln cluster, whereas <b>2</b> is a single-oxalate-connective mono-Ln^III Lindqvist tetramer with square tetra-Ln cluster. As far as we know, such di-Ln substituted Lindqvist fragment in <b>1</b> is observed for the first time. Moreover, <b>2</b> represents the first organic–inorganic hybrid square Ln-substituted isopolyoxotungstate. The solid-state luminescent properties of <b>1-Eu</b>, <b>1-Tb</b>, <b>2-Eu</b>, and <b>2-Tb</b> have been measured. <b>1-Eu</b> and <b>2-Eu</b> display intense, sharp, and narrow emission bands in the orange visible region that originate from the characteristic ⁵D₀ → ⁷F_<i>J</i> transitions, and their fluorescence lifetimes are 1.18 and 1.20 ms, respectively. <b>1-Tb</b> and <b>2-Tb</b> exhibit green photoluminescence mainly derived from ⁵D₄ → ⁷F₅ transitions. The decay behavior of <b>1-Tb</b> can be fitted to a biexponential function with lifetimes of τ₁ = 0.43 ms and τ₂ = 1.25 ms, whereas the decay behavior of <b>2-Tb</b> can be fitted to single exponential function with the lifetime of 1.03 ms. Magnetic susceptibilities of <b>1</b> and <b>2</b> have been measured, and the decline of χ_M<i>T</i> upon cooling for <b>1</b> and <b>2</b> is mostly related to the progressive thermal depopulation of the excited state of Ln cations

MDS-MSC induce CD4+CD25+Foxp3+Tregs.

<p>(A) CD4+CD25-T cells were cultured with MDS-MSC or normal-MSC for 5 days, and CD4+ T cells were collected. The expression of CD25 and Foxp3 on CD4+ T cells was analyzed by FACS. Results are expressed as mean±SD of triplicates of 4 separate experiments. *P≤0.05. (B) CD4+T cells were cocultured with MDS-MSC generated CD4+CD25+Foxp3+Tregs or normal-MSC generated CD4+CD25+Foxp3+Tregs in the presence of PHA, and the T-lymphocyte proliferation was measured on day 5 by [3H]-thymidine incorporation. Results are expressed as mean±SD of triplicates of 4 separate experiments. *P≤0.05. (C) MDS-MSC generated CD4+CD25+Foxp3+Tregs or normal-MSC generated CD4+CD25+Foxp3+Tregs inhibited the response of allogeneic T-lymphocyte in a dose-dependent manner. Responder CD2+ T-lymphocyte were stimulated with PHA for 5 days with or without graded dosed of MDS-MSC generated CD4+CD25+Foxp3+Tregs or normal-MSC generated CD4+CD25+Foxp3+Tregs. Results are expressed as mean±SD of triplicates of 4 separate experiments. *p≤0.05. (D) CD4+CD25-T cells were cultured with high-risk MDS-MSC or low-risk MDS-MSC for 5 days, and CD4+ T cells were collected. The expression of CD25 and Foxp3 on CD4+ T cells was analyzed by FACS. Results are expressed as mean±SD of triplicates of 4 separate experiments. *P≤0.05.</p

Fabrication and Characterization of Three-Dimensional (3D) Core–Shell Structure Nanofibers Designed for 3D Dynamic Cell Culture

Three-dimensional elastic nanofibers (3D eNFs) can offer a suitable 3D dynamic microenvironment and sufficient flexibility to regulate cellular behavior and functional protein expression. In this study, we report a novel approach to prepare 3D nanofibers with excellent mechanical properties by solution-assisted electrospinning technology and in situ polymerization. The obtained 3D eNFs demonstrated excellent biocompatible properties to meet cell culture requirements under a dynamic environment in vitro. Moreover, these 3D eNFs also promoted human bone marrow mesenchymal stem cells (hMSCs) adhesion and collagen expression under biomechanical stimulation. The results demonstrated that this dynamic cell culture system could positively impact cellular collagen but has no significant effect on the proliferation of hMSCs grown in the 3D eNFs. This work may give rise to a new approach for constructing a 3D cell culture for tissue engineering

MDS-MSC inhibit T-lymphocyte proliferation.

<p>Irradiated (15 Gy) MDS-MSC or normal-MSC were cultured for 5 days with CD2+ T-lymphocyte in the presence of PHA, then assessed by [3H]-thymidine incorporation. Data are expressed as mean±SD of triplicates of 5 separate experiments. *P≤0.05.</p

Induction of CD4+CD25+Foxp3+Tregs by MDS-MSC is dependent on TGFβ1.

<p>Western blot confirmed efficient knockdown of TGF-β1. (B) CD4+CD25-T cells were cultured with TGF-β1 knockdown MDS-MSC or normal-MSC for 5 days, and CD4+ T cells were collected. The expression of CD25 and Foxp3 on CD4+ T cells was analyzed by FACS. Results are expressed as mean±SD of triplicates of 5 separate experiments. *P≤0.05. (C) CD4+CD25-T cells were cultured with mutant siRNA transfected MDS-MSC or normal-MSC for 5 days, and CD4+ T cells were collected. The expression of CD25 and Foxp3 on CD4+ T cells was analyzed by FACS. Results are expressed as mean±SD of triplicates of 6 separate experiments. *P≤0.05. (D) anti-rhTGF-β1 mAb was added at the beginning of coculture of CD4+CD25-T cells and untransfected MDS-MSC or normal-MSC for 5 days, and CD4+ T cells were collected. The expression of CD25 and Foxp3 on CD4+ T cells was analyzed by FACS. Results are expressed as mean±SD of triplicates of 6 separate experiments. *P≤0.05.</p

Rectangle versus Square Oxalate-Connective Tetralanthanide Cluster Anchored in Lacunary Lindqvist Isopolytungstates: Syntheses, Structures, and Properties

Two types of unique oxalate-connective lanthanide-substituted isopolyoxotungstates, Na₁₀[Ln₂(C₂O₄)­(H₂O)₄(OH)­W₄O₁₆]₂·30H₂O (<b>1</b>) and K₄Na₁₆[Ln­(C₂O₄)­W₅O₁₈]₄·60H₂O (<b>2</b>) (Ln = Eu^III, Ho^III, Er^III, or Tb^III), have been synthesized under conventional aqueous solution conditions and structurally characterized by elemental analyses, IR spectra, single-crystal X-ray diffraction, and thermogravimetric analyses. It should be pointed out that the utilization of different alkaline cations leads to the formation of two structural types. When only Na⁺ ions are present in the system, type <b>1</b> was obtained, while when Na⁺ and K⁺ ions are used, type <b>2</b> was found. Complex <b>1</b> is a double-oxalate-bridging di-Ln substituted Lindqvist dimer with a rectangle tetra-Ln cluster, whereas <b>2</b> is a single-oxalate-connective mono-Ln^III Lindqvist tetramer with square tetra-Ln cluster. As far as we know, such di-Ln substituted Lindqvist fragment in <b>1</b> is observed for the first time. Moreover, <b>2</b> represents the first organic–inorganic hybrid square Ln-substituted isopolyoxotungstate. The solid-state luminescent properties of <b>1-Eu</b>, <b>1-Tb</b>, <b>2-Eu</b>, and <b>2-Tb</b> have been measured. <b>1-Eu</b> and <b>2-Eu</b> display intense, sharp, and narrow emission bands in the orange visible region that originate from the characteristic ⁵D₀ → ⁷F_<i>J</i> transitions, and their fluorescence lifetimes are 1.18 and 1.20 ms, respectively. <b>1-Tb</b> and <b>2-Tb</b> exhibit green photoluminescence mainly derived from ⁵D₄ → ⁷F₅ transitions. The decay behavior of <b>1-Tb</b> can be fitted to a biexponential function with lifetimes of τ₁ = 0.43 ms and τ₂ = 1.25 ms, whereas the decay behavior of <b>2-Tb</b> can be fitted to single exponential function with the lifetime of 1.03 ms. Magnetic susceptibilities of <b>1</b> and <b>2</b> have been measured, and the decline of χ_M<i>T</i> upon cooling for <b>1</b> and <b>2</b> is mostly related to the progressive thermal depopulation of the excited state of Ln cations