RESUMEN
Collagen (COL) and hydroxyapatite (HAp) are the major components of bone, therefore, COL-HAp composites have been widely used as bone substitutes to promote bone regeneration. We have reported that HAp-CaO fibers (HANFs), which were fabricated by a sol-gel route followed by an electrospinning technique, possessed good drug-loading efficiency and limited the burst release of tetracycline. In the present study, we used HANF fragments to evaluate the effects of COL-HANF scaffolds on MG63 osteoblast-like cell behaviors. COL-HANF composite scaffolds in which the average diameter of HANFs was approximately 461 ± 186 nm were fabricated by a freeze-drying process. The alkaline phosphatase activity and the protein expression levels of OCN and BSP showed that compared with COL alone, the COL-HANF scaffold promoted the differentiation of MG63 osteoblast-like cells. In addition, the bone regeneration ability of the COL-HANF scaffold was examined by using a rabbit condylar defect model in vivo. The COL-HANF scaffold was biodegradable and promoted bone regeneration eight weeks after the operation. Hence, we concluded that the COL-HANF scaffold has potential as a bone graft for bone tissue engineering.
RESUMEN
High coulombic efficiency and dendrite suppression in carbonate electrolytes remain challenges to the development of high-energy lithium ion batteries containing lithium metal anodes. Here we demonstrate an ultrathin (≤100 nm) lithium-ion ionomer membrane consisting of lithium-exchanged sulfonated polyether ether ketone embedded with polyhedral oligosilsesquioxane as a coating layer on copper or lithium for achieving efficient and stable lithium plating-stripping cycles in a carbonate-based electrolyte. Operando analyses and theoretical simulation reveal the remarkable ability of the ionomer coating to enable electric field homogenization over a considerably large lithium-plating surface. The membrane coating, serving as an artificial solid-electrolyte interphase filter in minimizing parasitic reactions at the electrolyte-electrode interface, enables dendrite-free lithium plating on copper with outstanding coulombic efficiencies at room and elevated (50 °C) temperatures. The membrane coated copper demonstrates itself as a promising current collector for manufacturing high-quality pre-plated lithium thin-film anode.
RESUMEN
Hydroxyapatite (HAp), a major inorganic and essential component of normal bone and teeth, is a promising biomaterial due to its excellent biocompatibility, bioactivity, and osteoconductivity. Therefore, synthetic HAp has been widely used as a bone substitute, cell carrier, and delivery carrier of therapeutic genes or drugs. Mesoporous materials have attracted considerable attention due to their relatively high surface area, large pore volume, high porosity, and tunable pore size. Recently, mesoporous HAp has also been successfully synthesized by the traditional template-based process and has been demonstrated to possess better drug-loading and release efficiencies than traditional HAp. It is widely accepted that cell adhesion and most cellular activities, including spreading, migration, proliferation, gene expression, surface antigen display, and cytoskeletal functioning, are sensitive to the topography and molecular composition of the matrix. The native extracellular matrix is a porous, nanofibrous structure. The major focus of this study is the fabrication of porous hydroxyapatite-CaO composite nanofibers (p-HApFs) and the investigation of its drug-release property. In this study, nanofibers were prepared by the sol-gel route and an electrospinning technique to mimic the three-dimensional structure of the natural extracellular matrix. We analyzed the components of fibers using X-ray diffraction and determined the morphology of fibers using scanning and transmission electron microscopy. The average diameter of the nanofibers was approximately 461 ± 186 nm. The N2 adsorptionâ»desorption isotherms were type IV isotherms. Moreover, p-HApFs had better drug-loading efficiency and could retard the burst release of tetracycline and maintain antibacterial activity for a period of 7 days. Hence, p-HApFs have the potential to become a new bone graft material.
RESUMEN
Hydroxyapatite (HAp) is the main inorganic component and an essential part of hard bone and teeth. Due to its excellent biocompatibility, bioactivity, and osteoconductivity, synthetic HAp has been widely used as a bone substitute, cell carrier, and therapeutic gene or drug carrier. Recently, numerous studies have demonstrated that strontium-substituted hydroxyapatite (SrHAp) not only enhances osteogenesis but also inhibits adipogenesis in mesenchymal stem cells. Mesoporous SrHAp has been successfully synthesized via a traditional template-based process and has been found to possess better drug loading and release efficiencies than SrHAp. In this study, strontium-substituted hydroxyapatite-CaO-CaCO3 nanofibers with a mesoporous structure (mSrHANFs) were fabricated using a solâ»gel method followed by electrospinning. X-ray diffraction analysis revealed that the contents of CaO and CaCO3 in the mSrHANFs decreased as the doping amount of Sr increased. Scanning electron microscopy (SEM) images showed that the average diameter of the mSrHANFs was approximately 200~300 nm. The N2 adsorptionâ»desorption isotherms demonstrated that the mSrHANFs possessed a mesoporous structure and that the average pore size was approximately 20~25 nm. Moreover, the mSrHANFs had excellent drug- loading efficiency and could retard the burst release of tetracycline (TC) to maintain antibacterial activity for over 3 weeks. Hence, mSrHANFs have the potential to be used as drug carriers in bone tissue engineering.