Biomimetic fabrication of new bioceramics-introduced fibrous scaffolds: From physicochemical characteristics to in vitro biological properties.

The combination of biodegradable polymers and bioactive inorganic materials is a promising method to mimic native tissue in bone regeneration. Toward this direction, electrospun fibrous scaffolds were successfully fabricated in the silk fibroin (SF) matrix containing new bioceramics on the basis of mesoporous bioactive glass/hydroxyapatite nanocomposite (MGHA). The physicochemical properties and surface hydrophilicity of these biphasic composite could be tailored by the addition of MGHA content. The increase in surface hydrophilicity and bioactivity of the as-spun composite fibers were observed with the increasing the nanoparticle contents while decreasing their tensile strength. In vitro cytotoxicity evaluation based on human bone marrow-derived mesenchymal stem cells (hMSCs) revealed that a positive osteogenic differentiation effect on SF/MGHA7 sample as evidenced by an increased alkaline phosphatase (ALP) activity, and upregulated osteoblastic gene expression compared with SF samples. These findings supported the suitability of the SF/MGHA composite system for its potential application in cell-material combination in bone tissue engineering.

Porous nitrogen-doped carbon derived from silk fibroin protein encapsulating sulfur as a superior cathode material for high-performance lithium-sulfur batteries.

The features of a carbon substrate are crucial for the electrochemical performance of lithium-sulfur (Li-S) batteries. Nitrogen doping of carbon materials is assumed to play an important role in sulfur immobilisation. In this study, natural silk fibroin protein is used as a precursor of nitrogen-rich carbon to fabricate a novel, porous, nitrogen-doped carbon material through facile carbonisation and activation. Porous carbon, with a reversible capacity of 815 mA h g(-1) at 0.2 C after 60 cycles, serves as the cathode material in Li-S batteries. Porous carbon retains a reversible capacity of 567 mA h g(-1), which corresponds to a capacity retention of 98% at 1 C after 200 cycles. The promising electrochemical performance of porous carbon is attributed to its mesoporous structure, high specific surface area and nitrogen doping into the carbon skeleton. This study provides a general strategy to synthesise nitrogen-doped carbons with a high specific surface area, which is crucial to improve the energy density and electrochemical performance of Li-S batteries.

Enhancing in vitro bioactivity and in vivo osteogenesis of organic-inorganic nanofibrous biocomposites with novel bioceramics.

Fabricating bioactive nanofibrous scaffolds from biodegradable polymers to mimic native tissue is an important approach in repairing bony defects. Silk fibroin (SF) may contribute to bone regeneration because of its excellent mechanical properties, slow degradability, and low osteoconductivity. A combination of bioceramic-polymer materials is generally used to provide an improved osteoconductive environment for bone healing. This study attempts developing for the first time an electrospun SF-based biocomposite system by introducing new bioceramics based on mesoporous bioactive glass/hydroxyapatite nanocomposite (MGHA). The addition of MGHA into the SF matrix could regulate the physicochemical properties and surface hydrophilicity, but induce weakened tensile properties as compared to pure SF. The excellent apatite-formation ability of a MGHA-introduced nanocomposite also improved the bioactivity of the composite. The biphasic composite increasingly degraded in PBS or enzyme solution in vitro compared with pure SF. In vivo evaluation of bone formation confirmed that SF/MGHA is more advantageous in bone reconstruction than the SF group for cranial bone defects. These results indicate the suitability of the SF/MGHA composite system in bone defects, demonstrating its potential application in bone tissue regeneration.