- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Nitrogen-Doped Titanium Dioxide Thin Films Formation on the Surface of PLLA Electrospun Microfibers Scaffold by Reactive Magnetron Sputtering Method
摘要： Nitrogen-doped thin titanium dioxide films formed by the reactive magnetron sputtering method on the surface of PLLA electrospun microfibers scaffold were investigated. It was shown that the chemical composition of the films is shifting from titanium dioxide (TiO2) composites saturated with C–NH, C=N, N–C=N and HN–C=O compounds to solid solutions of titanium oxides (TixOy) and titanium oxynitrides (TiOxNy) with the increased time of the treatment. An empirical model describing changes in the chemical composition of the surface due to the treatment was proposed. It was shown that the modification of the PLLA microfibers scaffolds surface improves cell-scaffold and cell–cell interactions with the highest number of viable adherent cells observed on the scaffold treated for 4 min.
关键词： Scaffolds,Reactive magnetron sputtering,Thin films,Biocompatibility
更新于2025-11-21 11:24:58
-
Laser additive manufacturing of biodegradable magnesium alloy WE43: a detailed microstructure analysis
摘要： WE43, a magnesium alloy containing yttrium and neodymium as main alloying elements, has become a well-established bioresorbable implant material. Implants made of WE43 are often fabricated by powder extrusion and subsequent machining, but for more complex geometries laser powder bed fusion (LPBF) appears to be a promising alternative. However, the extremely high cooling rates and subsequent heat treatment after solidification of the melt pool involved in this process induce a drastic change in microstructure, which governs mechanical properties and degradation behaviour in a way that is still unclear. In this study we investigated the changes in the microstructure of WE43 induced by LPBF in comparison to that of cast WE43. We did this mainly by electron microscopy imaging, and chemical mapping based on energy-dispersive X-ray spectroscopy in conjunction with electron diffraction for the identification of the various phases. We identified different types of microstructure: an equiaxed grain zone in the center of the laser-induced melt pool, and a lamellar zone and a partially melted zone at its border. The lamellar zone presents dendritic lamellae lying on the Mg basal plane and separated by aligned Nd-rich nanometric intermetallic phases. They appear as globular particles made of Mg3Nd and as platelets made of Mg41Nd5 occurring on Mg prismatic planes. Yttrium is found in solid solution and in oxide particles stemming from the powder particles’ shell. Due to the heat influence on the lamellar zone during subsequent laser passes, a strong texture developed in the bulk material after substantial grain growth.
关键词： Rapid solidification,Microstructure,Bone scaffolds,Electron microscopy,Biodegradable implants,WE43,Laser powder bed fusion,Magnesium
更新于2025-11-21 11:20:48
-
Rationally designed functionally graded porous Ti6Al4V scaffolds with high strength and toughness built via selective laser melting for load-bearing orthopedic applications
摘要： Functionally graded materials (FGMs) with porosity variation strategy mimicking natural bone are potential high-performance biomaterials for orthopedic implants. The architecture of FGM scaffold is critical to gain the favorable combination of mechanical and biological properties for osseointegration. In this study, four types of FGM scaffolds with different structures were prepared by selective laser melting (SLM) with Ti6Al4V as building material. All the scaffolds were hollow cylinders with different three-dimensional architectures and had gradient porosity resembling the graded-porous structure of human bone. Two unit cells (diamond and honeycomb-like unit cells) were used to construct the cellular structures. Solid support structures were embedded into the cellular structures to improve their mechanical performances. The physical characteristics, mechanical properties, and deformation behaviors of the scaffolds were compared systematically. All the as-built samples with porosities of ~52–67% exhibited a radial decreasing porosity from the inner layer to the outer layer, and their pore sizes ranged from ~420 to ~630 μm. The compression tests showed the Young’s moduli of all the as-fabricated samples (~3.79–~10.99 GPa) were similar to that of cortical bone. The FGM structures built by honeycomb-like unit cells with supporting structure in outer layer exhibited highest yield strength, toughness and stable mechanical properties which is more appropriate to build orthopedic scaffolds for load-bearing application.
关键词： Additive manufacturing,Orthopedic scaffolds,Mechanical properties,Functionally graded materials
更新于2025-09-23 15:19:57
-
Photoluminescent functionalized carbon quantum dots loaded electroactive Silk fibroin/PLA nanofibrous bioactive scaffolds for cardiac tissue engineering and nursing care application
摘要： Tissue engineering and stem cell rehabilitation are the hopeful aspects that are being investigated for the management of Myocardial Infarction (MI); cardiac patches have been used to start myocardial rejuvenation. In this study, we engineered p-phenylenediamine surface functionalized (modif-CQD) into the Silk fibroin/PLA (SF/PLA) nanofibrous bioactive scaffolds with improved physico-chemical abilities, mechanical and cytocompatibility to cardiomyocytes. The micrograph results visualized the morphological improved spherical modif-CQD have been equivalently spread throughout the SF/PLA bioactive cardiac scaffolds. The fabricated CQD@SF/PLA nanofibrous bioactive scaffolds were highly porous with fully consistent pores; effectively improved young modulus and swelling asset for the suitability and effective implantation efficacy. The scaffolds were prepared with rat cardiomyocytes and cultured for up to 7 days, without electrical incentive. After 7 days of culture, the scaffold pores all over the construct volume were overflowing with cardiomyocytes. The metabolic activity and viability of the cardiomyocytes in CQD@SF/PLA scaffolds were significantly higher than cardiomyocytes in Silk fibroin /PLA scaffolds. The integration of CQD also influenced greatly and increases the expression of cardiac- marker genes. The results of the present investigations evidently recommended that well-organized cardiac nanofibrous scaffold with greater cardiac related mechanical abilities and biocompatibilities for cardiac tissue engineering and nursing care applications.
关键词： Scaffolds,PLA,Carbon Quantum Dots,Silk fibroin
更新于2025-09-16 10:30:52
-
LED-based photoacoustic imaging for monitoring angiogenesis in fibrin scaffolds
摘要： Vascularization of engineered constructs is required to integrate an implant within the host blood supply. The ability to non‐invasively monitor neovascularization of an implanted construct is ultimately critical for translation. Laser speckle contrast analysis (LASCA), a widely used imaging technique within regenerative medicine, has high spatial resolution but offers limited imaging depth and is only sensitive to perfused blood vessels. As an emerging technology, photoacoustic (PA) imaging can provide centimeters of imaging depth and excellent sensitivity in vascular mapping. PA imaging in combination with conventional ultrasound (US) imaging offers a potential solution to this challenge in regenerative medicine. In this work, we used an LED‐based PA‐US dual system to image and monitor angiogenesis over 7 days in fibrin‐based scaffolds subcutaneously implanted in mice. Scaffolds, with or without basic fibroblast growth factor (bFGF), were imaged on day 0 (i.e., post implantation), 1, 3, and 7 with both LASCA and PA‐US imaging systems. Quantified perfusion measured by LASCA and PA imaging were compared with histologically‐determined blood vessel density on day 7. Vessel density corroborated with changes in perfusion measured by both LASCA and PA. Unlike LASCA, PA imaging enabled delineation of differences in neovascularization in the upper and the lower regions of the scaffold. Overall, this study has demonstrated that PA imaging could be a non‐invasive and highly sensitive method for monitoring vascularization at depth in regenerative applications.
关键词： Photoacoustic Imaging,LED-based Imaging,Fibrin Scaffolds,Tissue Engineering,Angiogenesis
更新于2025-09-11 14:15:04
-
Micro-patterned cell orientation of cyanobacterial liquid-crystalline hydrogels
摘要： Control of cell extension direction is crucial for the regeneration of tissues, which are generally composed of oriented molecules. The scaffolds of highly-oriented liquid crystalline polymer chains were fabricated by casting cyanobacterial mega-saccharides, sacran, on parallel-aligned micrometer bars of polystyrene (PS). Polarized microscopy revealed that the orientation was in transverse direction to the longitudinal axes of the PS bars. Swelling behavior of the micro-patterned hydrogels was dependent on the distance between the PS bars. The mechanical properties of these scaffolds were dependent on the structural orientation; additionally, the Young’s moduli in the transverse direction were higher than those in the parallel direction to the major axes of the PS bars. Further, fibroblast L929 cells were cultivated on the oriented scaffolds to be aligned along the orientation axis. L929 cells cultured on these scaffolds exhibited uniaxial elongation.
关键词： Cell orientation,Liquid crystal hydrogels,Micropatterned scaffolds,Cyanobacteria,Sulfated polysaccharides
更新于2025-09-09 09:28:46
-
[IEEE 2018 24th International Conference on Pattern Recognition (ICPR) - Beijing, China (2018.8.20-2018.8.24)] 2018 24th International Conference on Pattern Recognition (ICPR) - Deep Learning Based Bioresorbable Vascular Scaffolds Detection in IVOCT Images
摘要： Bioresorbable Vascular Scaffolds (BVS) are currently one of the most frequently-used type of stent during percutaneous coronary intervention. It’s very important to conduct struts malapposition analysis during operation. Currently, BVS malapposition analysis in intravascular optical coherence tomography (IVOCT) images is mainly conducted manually, which is labor intensive and time consuming. In our previous work, a novel framework was presented to automatically detect and segment BVS struts for malapposition analysis. However, limited by the detection performance, the framework faced some challenges under complex background. In this paper, we proposed a robust BVS struts detection method based on Region-based Fully Convolutional Network (R-FCN). The detection model mainly consisted of two modules: 1) a Region Proposal Network (RPN), used to extract struts region of interest (ROIs) in the image and, 2) a detection module, used to classify the ROIs and regress a bounding box for each ROI. The network was initialized by pre-trained ImageNet model and then trained based on our labeled data which contained 1231 IVOCT images. Tested on a total of 480 IVOCT images with 4096 BVS struts, our method achieved 97.9% true positive rate with 4.79% false positive rate. It concludes that the proposed method is efficient and robust for BVS struts detection.
关键词： struts detection,IVOCT,R-FCN,Bioresorbable Vascular Scaffolds,malapposition analysis
更新于2025-09-04 15:30:14