Porous β-tricalcium phosphate (β-TCP) has been used for bone repair and replacement in clinics due to its excellent biocompatibility, osteoconductivity, and biodegradability. However, the application of β-TCP has been limited by its brittleness. Here, we demonstrated that an interconnected porous β-TCP scaffold infiltrated with a thin layer of poly(lactic-co-glycolic acid) (PLGA) polymer showed improved mechanical performance compared to an uncoated β-TCP scaffold while retaining its excellent interconnectivity and biocompatibility. The infiltration of PLGA significantly increased the compressive strength of β-TCP scaffolds from 2.90 to 4.19 MPa, bending strength from 1.46 to 2.41 MPa, and toughness from 0.17 to 1.44 MPa, while retaining an interconnected porous structure with a porosity of 80.65%. These remarkable improvements in the mechanical properties of PLGA-coated β-TCP scaffolds are due to the combination of the systematic coating of struts, interpenetrating structural characteristics, and crack bridging. The in vitro biological evaluation demonstrated that rat bone marrow stromal cells (rBMSCs) adhered well, proliferated, and expressed alkaline phosphatase (ALP) activity on both the PLGA-coated β-TCP and the β-TCP. These results suggest a new strategy for fabricating interconnected macroporous scaffolds with significantly enhanced mechanical strength for potential load-bearing bone tissue regeneration. 相似文献
Sediment-water interfaces are important interfaces for lakes, which are related to most environmental and ecological problems. Wind-induced waves cause secondary pollution via sediment resuspension. Since the coupling mechanism of water, resuspended sediments, and phosphorus affects the release of phosphorus (P) near the interface, a coupled model was explored for two sediment types with different adsorption-desorption capabilities to examine sediment resuspension and P release. The relationships among wind speed, wave characteristics, sediment distribution and P concentration were obtained. For different sediments, the unit sediment desorption release is negatively correlated with wind speed. When sediments are resuspended under low or moderate wind speed, the P concentration in the overlying water increases abruptly, hampering diffusion. P release exhibits the characteristics of concentrated release in a small region and changes the water environment rapidly.
Monodisperse poly(acrylic acid)‐modified Fe3O4 (PAA@Fe3O4) hybrid microspheres with dual responses (magnetic field and pH) were successfully fabricated. The PAA polymer was encapsulated into the inner cavity of Fe3O4 hollow spheres by a vacuum‐casting route and photo‐initiated polymerization. TEM images show that the samples consist of monodisperse porous spheres with a diameter around 200 nm. The Fe3O4 spheres, after modification with the PAA polymer, still possess enough space to hold guest molecules. We selected doxorubicin (DOX) as a model drug to investigate the drug loading and release behavior of as‐prepared composites. The release of DOX molecules was strongly dependent on the pH value due to the unique property of PAA. The HeLa cell‐uptake process of DOX‐loaded PAA@Fe3O4 was observed by confocal laser scanning microscopy (CLSM). After being incubated with HeLa cells under magnet magnetically guided conditions, the cytotoxtic effects of DOX‐loaded PAA@Fe3O4 increased. These results indicate that pH‐responsive magnetic PAA@Fe3O4 spheres have the potential to be used as anticancer drug carriers. 相似文献
A new one-dimensional tellurite phosphate, Ba2TeO(PO4)2 has been synthesized by standard solid-state reaction techniques using BaCO3, TeO2, and (NH4)H2PO4 as reagents. The structure of Ba2TeO(PO4)2 was determined by single-crystal X-ray diffraction. Ba2TeO(PO4)2 crystallizes in the triclinic space group P-1 (No. 2), with , , , α=76.843(4)°, β=79.933(4)°, γ=75.688(4)°, , and Z=2. Ba2TeO(PO4)2 has a novel one-dimensional chain structure that is composed of PO4 tetrahedra and TeO5 polyhedra. Te4+ cations are in asymmetric coordination environments attributable to their lone pairs. The lone pairs on the Te4+ cations point in the [100] and [−100] direction and interact with the Ba2+ cations. Infrared, Raman, and UV-Vis diffuse reflectance spectroscopy, thermogravimetric analysis, and dipole moment calculations are also presented. 相似文献
We demonstrate the fluorescence mapping of protein microarrays by the technique of scanning near-field optical microscopy
(SNOM) and confocal microscopy. Micron sized spots (300 μm) of human Immunoglobulin G (hIgG) protein with and without a Cy3
dye labeling have been fabricated on glass substrates by an immobilization method which makes use of calixcrown derivatives
termed Prolinker. We have also tried to probe into the well-known “doughnut effect” observed in fluorescence images of proteins
using the SNOM technique. The topographic and fluorescence SNOM images revealed that the number of proteins at the boundary
of the spot were more than at the center in the case of the microarray spot which showed brighter luminescence at the edge
than at the center in the confocal image. 相似文献