Journal of biomedical materials research. Part A最新文献

Currently, percutaneous coronary intervention, based on stenting, is employed to provide scaffolding support to correct occlusion and diminished blood supply caused by atherosclerosis. To guarantee procedural efficacy and enhanced structural integrity of stents, further developments of stent materials and manufacturing methods are particularly required. In this paper, 316L stainless steel stents fabricated by additive manufacturing are studied through heat treatment, microstructural characterization, and mechanical deformation in vitro. After solution heat treatment conducted at 1200°C for durations ranging from 1 to 4 h, coarsening of columnar grains and changes in the grain boundary characters were observed, indicating the potential of microstructure modification through heat treatment. Electrochemical polishing can effectively improve surface quality by dissolving surface imperfections caused by partially sintered powders and uneven solidification processes, characteristics of additively manufactured parts. Mechanical deformation behaviors are evaluated by expansion tests before and after heat treatment. Specifically, free expansion tests are carried out to assess the mechanical performance of the stent alone, while in vitro mechanical performances are evaluated using silicone arteries filled with silicone plaques, corresponding to a stenosis rate of 70%. Coarsened grain microstructures in heat-treated stents lead to improved expansion flexibility, reduced dog-boning ratio, and slightly increased recoil, as compared to the as-printed stents. Results demonstrate the viability of improving the mechanical performance of additively manufactured 316L stainless steel stents through heat treatment process.

Hydrogels are an important class of biomaterials that permit cells to be cultured and studied within engineered microenvironments of user-defined physical and chemical properties. Though conventional 3D extrusion and stereolithographic (SLA) printing readily enable homogeneous and multimaterial hydrogels to be formed with specific macroscopic geometries, strategies that further afford spatiotemporal customization of the underlying gel physicochemistry in a non-discrete manner would be profoundly useful toward recapitulating the complexity of native tissue in vitro. Here, we demonstrate that grayscale control over local biomaterial biochemistry and mechanics can be rapidly achieved across large constructs using an inexpensive (~$300) and commercially available liquid crystal display (LCD)-based printer. Template grayscale images are first processed into a “height-extruded” 3D object, which is then printed on a standard LCD printer with an immobile build head. As the local height of the 3D object corresponds to the final light dosage delivered at the corresponding xy-coordinate, this method provides a route toward spatially specifying the extent of various dosage-dependent and biomaterial, forming/modifying photochemistries. Demonstrating the utility of this approach, we photopattern the grayscale polymerization of poly(ethylene glycol) (PEG) diacrylate gels, biochemical functionalization of agarose- and PEG-based gels via oxime ligation, and the controlled 2D adhesion and 3D growth of cells in response to a de novo-designed α5β1-modulating protein via thiol-norbornene click chemistry. Owing to the method's low cost, simple implementation, and high compatibility with many biomaterial photochemistries, we expect this strategy will prove useful toward fundamental biological studies and functional tissue engineering alike.

Silicocarnotite (Ca₅(PO₄)₂(SiO₄)) is an inorganic crystalline material classified as a silicophosphate. Its chemical composition is similar to that of calcium hydroxyapatite (Ca₁₀(PO₄)₆(OH)₂) and silicon-substituted hydroxyapatite (Ca₁₀(PO₄)_6-x(SiO₄)_x(OH)_2-x-□). Given the critical role of silicon ions in bone tissue metabolism, mineralization, and collagen synthesis, silicon-enriched hydroxyapatites have long been of significant interest in regenerative medicine. The natural presence of silicate ions in the structure of silicophosphates has prompted research into their synthesis and potential application as bone substitute materials in reconstructive and reparative bone surgery. This article reviews the current state of knowledge on silicocarnotite, including its physicochemical and biological properties, the application potential, and prospective research directions.

Gastrectomy is often associated with serious complications that lack effective treatments. Despite the widespread adoption in tissue engineering, the rapid degradation of small intestinal submucosa (SIS) compromised its performance in gastric tissue engineering. Thereby, genipin, a natural crosslinking agent, was employed to modify SIS, and the potential of genipin-crosslinked SIS (GP-SIS) in promoting the regeneration of full-thickness gastric defects was explored. The data on crosslinking efficiency demonstrated that genipin can efficiently fix SIS. GP-SIS exhibited high resistance against collagenase, enhanced hydrothermal stability, and improved mechanical properties according to in vitro degradation, shrinkage temperature, and uniaxial tensile tests. Additionally, GP-SIS maintained excellent biocompatibility based on a cytotoxicity test and rat subcutaneous implantation. In the rat full-thickness gastric wall defect model, GP-SIS, serving as a protective barrier, accelerated the newly formed granulation tissues and fibrosis, avoiding the occurrence of gastric leakage. Its niche and growth factors further promoted the vascularization and epithelialization of the regenerated area. In conclusion, GP-SIS will be feasible in the near future for gastric wall reconstruction after gastrectomy.

Considering the search for new biocompatible intracanal medicaments that can preserve remaining cells and stimulate bone tissue repair in the periapical region, this study aimed to synthesize and characterize the physicochemical properties of morin-loaded chitosan-poloxamer hydrogel (MCP) as well as to evaluate its osteogenic potential. Morin hydrate (M) was loaded into chitosan-poloxamer (CP) hydrogel and the resulting particles were characterized by infrared spectroscopy (FTIR), UV–vis spectrophotometer and scanning electron microscopy. Biological assays evaluated the metabolic activity, cell morphology and alkaline phosphatase (ALP) activity of human bone marrow stem cells (HBMSC) in three different settings, such as the exposure to dissolved morin, hydrogel's leachates and assembled particles by indirect contact. Cells cultured in standard culture conditions were used as control. The effect of CP and MCP particles on the formation of collagenous and mineralized tissues was also assessed within the organotypic model of segmented embryonic chick femora. Datasets were assessed for one-way analysis of variance (ANOVA), followed by Tukey's post hoc test (p < 0.05). Morin at 50 μg/mL was cytocompatible and increased ALP activity. CP and MCP particles showed stability, and morin was entrapped in the hydrogel matrix without changing its chemical structure. Cultures treated with 30-min CP and MCP hydrogel leachates presented significantly higher metabolic activity compared to control. By indirect contact, CP particles increased metabolic activity, but only MCP particles induced an upregulation of ALP activity in comparison to control. The amount of collagenous tissue and mineralized area on the fractured embryonic chick femora was greater in MCP particles compared to CP counterparts. Chitosan-poloxamer platforms are suitable systems to delivery morin, enhancing cell proliferation and bone mineralization, which upholds its application as intracanal medication for endodontic purposes.

Engineering cellular microenvironments with biomaterials is an effective strategy for endothelial cell expansion and functionality in vascular tissue engineering. The basement membrane (BM) is a natural vascular endothelium microenvironment that plays an important role in promoting rapid expansion and function of endothelial cells. However, mimicking the crucial function of BM with an ideal biomaterial remains challenging. In this study, we developed a cell-derived decellularized extracellular matrix (c-dECM) paper to mimic the role of BM in endothelial cell expansion and function. The results showed that c-dECM paper was a stable, biocompatible, and biodegradable scaffold that significantly promoted endothelial cell expansion by modulating cell migration, adhesion, and proliferation both in vivo and in vitro. Moreover, the biomimetic c-dECM paper can profoundly promote endothelial cell function by increasing the synthesis and release of nitric oxide (NO) and prostaglandin I2 (PGI2) and upregulating the expression of anticoagulant and vascularized genes, including thrombomodulin (THBD), tissue factor pathway inhibitor (TFPI), endothelial growth factor (VEGF) and endoglin (CD105). These data indicate that the c-dECM is a potential biomaterial for constructing vascular tissue engineering scaffolds or developing in vitro models to study the functional mechanisms of endothelial cells.