Natural lotus root-based scaffolds for bone regeneration

A high incidence of bone defects and the limitation of autologous bone grafting require 3 D scaffolds for bone repair. Compared with synthetic materials, natural edible materials possess outstanding advantages in terms of biocompatibility, bioactivities and low manufacturing cost for bone tissue engineering. In this work, attracted by the natural porous/fabric structure, good biocompatibility and bioactivities of the lotus root, the lotus root-based scaffolds were fabricated and investigated the...     

One-step Growth of Hierarchical Nanotreelike TiO_2 on ITO without Template and Its Application in Gas Sensor

In this work, a distinctive hierarchical tree-like rutile TiO_2 architecture growing directly on the conductive surface of indium tin oxide(ITO) conductive glass substrates was successfully prepared via a facile one-step hydrothermal process, where titanium butoxide used as Ti source and HCl as an acidic medium solution. The as-obtained products were characterized by X-ray diffraction(XRD), field emission scanning electron microscopy(FE-SEM), transmission electron microscopy(TEM), selected area electron diffraction(SAED) and applied in gas sensor. The characterization of FE-SEM indicates that the morphology of the products can be controlled by regulating solution acidity, the amount of titanium butoxide, reaction time, addition agents, and so on. The gas sensing test shows that the sensor fabricated with 3D nanotree-like rutile TiO_2 has higher gas response towards CH3 COCH3 gas than those with 1 D rod-like TiO_2 or common TiO_2 precipitate, indicating that the 3D nanotree-like architectures may be promising gas sensitive materials.     

Growth of Fe3O4 Nanorod Arrays on Graphene Sheets for Application in Electromagnetic Absorption Fields

A facial strategy is developed to fabricate a three‐dimensional (3D) Fe₃O₄ nanorod array/graphene architecture, in which Fe₃O₄ nanorods with a length and diameter of about 600 and 100 nm, respectively, are grown on both surfaces of the graphene sheets. The measured electromagnetic parameters show that the 3D architecture exhibits excellent electromagnetic wave‐absorption properties, that is, more than 99 % of electromagnetic wave energy can be attenuated by the 3D architecture if it is added in only 20 wt % of the paraffin matrix, as the thickness of the absorber is in the range from 2.38 to 5.00 mm. The analysis of the electromagnetic (EM) absorption mechanism reveals that the excellent EM absorption properties are related to the special 3D architecture, and therefore, the construction of graphene‐based 3D heteronanostructures is effective in obtaining lightweight EM absorbers with strong absorption properties.     

生物质羟基磷灰石作为模板制备三维石墨烯

As a new 2D material with excellent chemical stability, good electric conductivity, and high specific surface area, graphene has been widely used in energy storage and conversion devices. However, 2D graphene layers are easily stacked, which may significantly reduce the surface area and degrade the excellent electrical properties of graphene. To avoid this, one of the most effective methods is to construct 3D graphene (3DG) with specific porous microstructures. Chemical vapor deposition (CVD) is an important method for the synthesis of high-quality 3DG, where templates play a defining role in controlling the structure and cost of 3DG. Metallic materials with 3D microstructures, such as nickel foam, have proven to be useful as substrates for the growth of high-quality 3DG. However, metal substrates are usually expensive, and the pickling solution generated after etching may cause environmental problems. Therefore, non-metallic substrate materials with lower costs have been investigated for the preparation of 3DG. Herein, we developed a novel template material, mammal bone ashes, for the CVD preparation of 3DG. Mammal bone ash is an inexpensive and abundant biomass hydroxyapatite. During the high-temperature CVD reaction, the bone ash powders were slightly sintered to form a continuous porous structure with graphene coating. The morphology of 3DG is inherited from the microstructure of bone ash templates. After removing the bone ash template with hydrochloric acid, the template-grown 3DG was obtained with a unique bicontinuous structure, i.e. both the graphene framework and the void space were continuous. In addition, the pickling solution of the bone ash templates after etching was exactly the same as that for the raw materials for the production of phosphoric acid to achieve high atom utilization. We further optimized the graphitization degrees, layer number, and porous morphology of 3DGs. The microstructure evolution of 3DG is highly relevant to the layer thickness and uniformity of graphene layers. A short growth time would lead to a non-uniform and thin layer of graphene, which is not able to support a complex 3D porous structure. In contrast, a uniform graphene layer with proper thickness is capable of forming a robust 3D architecture. In addition, the facile CVD method can be extended to a series of metal phosphate templates, including tricalcium phosphate [Ca₃(PO₄)₂], trimagnesium phosphate [Mg₃(PO₄)₂], and aluminum phosphate [AlPO₄]. 3DG with bicontinuous morphology is promising as a conductive frame material in electrochemical energy storage devices. As an illustration, high-performance Li-S batteries were fabricated by the uniform composition of an S cathode on 3DG. In comparison with heavily stacked 2D graphene sheets in reduced graphene oxide / S composite, the non-flat structure of 3DGs remained unchanged even after the harsh melt-diffusion process of high-viscosity liquid sulfur. The resulting 3DG/S cathode delivered a high specific capacity of ~550 mAh∙g^-1 at a high current rate (2C). Our work opens an avenue to the low-cost and high-utility production of 3D graphene, which could be integrated with the well-developed phosphorus chemical industry.     

Three-dimensional characterization of pigment dispersion in dried paint films using focused ion beam-scanning electron microscopy

The combination of integrated focused ion beam-scanning electron microscope (FIB-SEM) serial sectioning and imaging techniques with image analysis provided quantitative characterization of three-dimensional (3D) pigment dispersion in dried paint films. The focused ion beam in a FIB-SEM dual beam system enables great control in slicing paints, and the sectioning process can be synchronized with SEM imaging providing high quality serial cross-section images for 3D reconstruction. Application of Euclidean distance map and ultimate eroded points image analysis methods can provide quantitative characterization of 3D particle distribution. It is concluded that 3D measurement of binder distribution in paints is effective to characterize the order of pigment dispersion in dried paint films.     

Drug‐Loaded Elastin‐Like Polypeptide–Collagen Hydrogels with High Modulus for Bone Tissue Engineering

Emphasizing the role of hydrogel stiffness and cellular differentiation, this study develops collagen and elastin‐like polypeptide (ELP)–based bone regenerative hydrogels loaded with recombinant human bone morphogenetic protein‐2 (rhBMP‐2) and doxycycline with mechanical properties suitable for osteogenesis. The drug‐incorporated collagen–ELP hydrogels has significantly higher modulus of 35 ± 5 kPa compared to collagen‐only hydrogels. Doxycycline shows a bi‐phasic release with an initial burst release followed by a gradual release, while rhBMP‐2 exhibits a nearly linear release profile for all hydrogels. The released doxycycline shows anti‐microbial activity against Pseudomonas aeruginosa, Streptococcus sanguinis, and Escherichia coli. Microscopic observation of the hydrogels reveals their interconnected, macroporous, 3D open architecture with pore diameters between 160 and 400 µm. This architecture supports human adipose–derived stem cell attachment and proliferation from initial days of cell seeding, forming a thick cellular sheath by day 21. Interestingly, in collagen and collagen–ELP hydrogels, cell morphology is elongated with stretched slender lamellipodial formation, while cells assemble as spheroidal aggregates in crosslinked as well as drug‐loaded hydrogels. Osteogenic markers, alkaline phosphatase and osteocalcin, are expressed maximally for drug‐loaded hydrogels compared to those without drugs. The drug‐loaded collagen–ELP hydrogels are thus promising for combating bacterial infection and promoting guided bone regeneration.     

Affecting an Ultra-High Work Function of Silver

An ultra-high increase in the WF of silver, from 4.26 to 7.42 eV, that is, an increase of up to circa 3.1 eV is reported. This is the highest WF increase on record for metals and is supported by recent computational studies which predict the potential ability to affect an increase of the WF of metals by more than 4 eV. We achieved the ultra-high increase by a new approach: Rather than using the common method of 2D adsorption of polar molecules layers on the metal surface, WF modifying components, l -cysteine and Zn(OH)₂, were incorporated within the metal, resulting in a 3D architecture. Detailed material characterization by a large array of analytical methods was carried out, the combination of which points to a WF enhancement mechanism which is based on directly affecting the charge transfer ability of the metal separately by cysteine and hydrolyzed zinc(II), and synergistically by the combination of the two through the known Zn-cysteine finger redox trap effect.     

3D‐Printing of Functionally Graded Porous Materials Using On‐Demand Reconfigurable Microfluidics

Tailoring the morphology of macroporous structures remains one of the biggest challenges in material synthesis. Herein, we present an innovative approach for the fabrication of custom macroporous materials in which pore size varies throughout the structure by up to an order of magnitude. We employed a valve‐based flow‐focusing junction (vFF) in which the size of the orifice can be adjusted in real‐time (within tens of milliseconds) to generate foams with on‐line controlled bubble size. We used the junction to fabricate layered and smoothly graded porous structures with pore size varying in the range of 80–800 μm. Additionally, we mounted the vFF on top of an extrusion printer and 3D‐printed constructs characterized by a predefined 3D geometry and a controlled, spatially varying internal porous architecture, such as a model of a bone. The presented technology opens new possibilities in macroporous material synthesis with potential applications ranging from tissue engineering to aerospace industry and construction.     

Characterization of 3D DNA Assemblies Using Cryogenic Electron Microscopy

DNA nanotechnology utilizes DNA double strands as building units for self-assembly of DNA nanostructures.The specific base-pairing interaction between DNA molecules is the basis of these assemblies.After decades of development,this technology has been able to construct complex and programmable structures.With the increase in delicate nature and complexity of the synthesized nanostructures,a characterization technology that can observe these structures in three dimensions has become necessary,and developing such a technology is considerably challenging.DNA assemblies have been studied using different characterization methods including atomic force microscopy(AFM),scanning electron microscopy(SEM),and transmission electron microscopy(TEM).However,the three-dimensional(3D)DNA assemblies always collapse locally due to the dehydration during the drying process.Cryogenic electron microscopy(cryo-EM)can overcome the challenge by maintaining three-dimensional morphologies of the cryogenic samples and reconstruct the 3D models from cryogenic samples accordingly by collecting thousands of two-dimensional(2D)projection images,which can restore their original morphologies in solution.Here,we have reviewed several typical cases of 3D DNA-assemblies and highlighted the applications of cryo-EM in characterization of these assemblies.By comparing with some other characterization methods,we have shown how cryo-EM promoted the development of structural characterization in the field of DNA nanotechnology.     

Affecting an Ultra‐High Work Function of Silver

An ultra‐high increase in the WF of silver, from 4.26 to 7.42 eV, that is, an increase of up to circa 3.1 eV is reported. This is the highest WF increase on record for metals and is supported by recent computational studies which predict the potential ability to affect an increase of the WF of metals by more than 4 eV. We achieved the ultra‐high increase by a new approach: Rather than using the common method of 2D adsorption of polar molecules layers on the metal surface, WF modifying components, l ‐cysteine and Zn(OH)₂, were incorporated within the metal, resulting in a 3D architecture. Detailed material characterization by a large array of analytical methods was carried out, the combination of which points to a WF enhancement mechanism which is based on directly affecting the charge transfer ability of the metal separately by cysteine and hydrolyzed zinc(II), and synergistically by the combination of the two through the known Zn‐cysteine finger redox trap effect.     

Oxygen Plasma Technology-Assisted Preparation of Three-Dimensional Reduced Graphene Oxide/Polypyrrole/Strontium Composite Scaffold for Repair of Bone Defects Caused by Osteoporosis

Repairs of bone defects caused by osteoporosis have always relied on bone tissue engineering. However, the preparation of composite tissue engineering scaffolds with a three-dimensional (3D) macroporous structure poses huge challenges in achieving osteoconduction and osteoinduction for repairing bone defects caused by osteoporosis. In the current study, a three-dimensional macroporous (150–300 μm) reduced graphene oxide/polypyrrole composite scaffold modified by strontium (Sr) (3D rGO/PPY/Sr) was successfully prepared using the oxygen plasma technology-assisted method, which is simple, safe, and inexpensive. The findings of the MTT assay and AO/EB fluorescence double staining showed that 3D rGO/PPY/Sr has a good biocompatibility and effectively promoted MC3T3-E1 cell proliferation. Furthermore, the ALP assay and alizarin red staining showed that 3D rGO/PPY/Sr increased the expression levels of ALP activity and the formation of calcified nodules. The desirable biocompatibility, osteoconduction, and osteoinduction abilities, assure that the 3D macroporous rGO/PPY/Sr composite scaffold offers promising potential for use in the repair of bone defects caused by osteoporosis in bone tissue engineering.     

An Effective Osteogenesis Porous CaP/Collagen Interface Compatible with Various Substrates Fabricated by Controlled Mineralization in a Delicately Adjustable Organic Matrix

Increasing bone formation on the surfaces of implants such as screws, plates, or shims holds great significance for clinical medicine. However, osteogenesis implant coatings that mimic natural bone in terms of both their components and structural features are still lacking. Here we report the biomimetic interface of calcium phosphate (CaP) in a collagen matrix fabricated by controlled mineralization that presents biomimetic porous features. The porous CaP/collagen interface, with a thickness of about 1 μm, significantly enhances osteogenesis, as verified at both the gene and protein levels as well as by in vivo experiments. Taking advantage of the generality of the method, the biomimetic interface was prepared on a variety of substrates, including conductive substrates, 3D metal meshes, plastic or elastic substrates, and even on filter papers. The adjustability and generality of the method have enabled new characterization tests to be developed during experiments on cells and thus should greatly facilitate clinical medicine and tissue engineering.     

Manipulation of self-assembled three-dimensional architecture in reusable acoustofluidic device

Reconstructing of cell architecture plays a vital role in tissue engineering. Recent developments of self-assembling of cells into three-dimensional (3D) matrix pattern using surface acoustic waves have paved a way for a better tissue engineering platform thanks to its unique properties such as nature of noninvasive and noncontact, high biocompatibility, low-power consumption, automation capability, and fast actuation. This article discloses a method to manipulate the orientation and curvature of 3D matrix pattern by redesigning the top wall of microfluidic chamber and the technique to create a 3D longitudinal pattern along preinserted polydimethylsiloxane (PDMS) rods. Experimental results showed a good agreement with model predictions. This research can actively contribute to the development of better organs-on-chips platforms with capability of controlling cell architecture and density. Meanwhile, the 3D longitudinal pattern is suitable for self-assembling of microvasculatures.     

非金属元素掺杂及三维花状多级结构对介孔TiO_2可见光催化性能的促进作用

分别以尿素和葡萄糖为氮源和碳源,在温和条件下合成了具有三维花状多级结构的氮/碳掺杂二氧化钛.研究了非金属元素掺杂及三维花状多级结构对介孔TiO_2可见光催化性能的促进作用,结果表明,二者在增强TiO_2在可见光区域的吸收和提高TiO_2材料的光催化活性方面起到了协同促进的作用.     

Effect on carbon lengthening at the side chain terminal of 1 alpha,25-dihydroxyvitamin D3 for calcium regulating activity

A series of analogs of 1 alpha,25-dihydroxyvitamin D3 [1,25-(OH)2D3 (1)] with alkyl substitutions in 26- and 27-positions have been tested for their activity 1) in competing with 1,25-(OH)2D3 for binding to chick intestinal cytosol receptor, 2) in ability for formation of multinucleated cells (MNC) with various osteoclastic cell characteristics from blast cells, and 3) in stimulating bone calcium mobilization in vitamin D-deficient rats. The relative potencies of 1,25-(OH)2D3, 1 alpha,25-dihydroxy-26,27-dimethylvitamin D3 (2), 1 alpha,25-dihydroxy-26,27-diethylvitamin D3 (3), and 1 alpha,25-dihydroxy-26,27-dipropylvitamin D3 (4) in competing for intestinal cytosolic binding were 1:1.1:0.25:0.05. The similar order of the abilities on formation of the multinucleated cells in the same series was observed. In a bone calcium mobilization test with vitamin D-deficient rats, 1 alpha,25-dihydroxy-26,27-dimethylvitamin D3 showed slightly less activity than 1,25-(OH)2D3 at 12 h after administration, but long lasting activity was observed during time course experiments. 1 alpha,25-Dihydroxy-26,27-diethylvitamin D3, and 1 alpha,25-dihydroxy-26,27-dipropylvitamin D3 were found to be much less active than 1,25-(OH)2D3 in a bone calcium mobilization test.     

Three-dimensional conic beam X-ray microtomography in bone quality

In recent years, the 3D X-ray microcomputed tomography (3DμCT) has become a useful method to access the internal geometry based microarchitecture of bones. All measurements are based on the image quality. In this context, the aim of this work is to investigate bone quality in terms of strength parameters determined by 3DμCT. The system that was used to do the 3DμCT was a microfocus Fein Focus which has a microfocus X-ray tube, adjustment of the magnification factor of the captured image by mobile supports and an image intensifier with a diameter of 9 in. The results show that microtomography by microfocus X-ray tube is a powerful technique that can be used to analyze bone microstructures. A quantification procedure conducted with a locally developed program, produced images with 20 μm of resolution for different bone samples.     

Rigid optically-active D2 and D3 macrocycles

The synthesis and characterization of novel optically-active macrocycles, obtained by esterification reaction from a binaphthyl-containing diol and phthalic or terephthalic acids, and possessing overall D2 or D3 symmetry, is described.     

Novel tailormade Bi4MO4(PO4)2 structural type (M = Mg, Zn)

In the Bi(2)O(3)-MO-P(2)O(5) ternary system, the commonly observed sizable 1D ribbon-like units have been extended to their 2D infinite end member, leading to the novel tailormade Bi(4)MO(4)(PO(4))(2) compounds. It contains planar [Bi(2)O(2)](2+) derivatives, separated by two slabs of PO(4), which create channels hosting the M(2+) cations (M = Mg, Zn). For both compounds, supercell orderings occur comparatively to the predicted ideal crystal structure (V(Mg) = 2V(ideal) and V(Zn) = 8V(ideal)). In the Mg case a transition into the ideal lattice occurs above 450 °C. In spite of the conceptual assembly of 2D motifs, the final architecture is three-dimensional due to strong interbonds. Thus, our work gives new insights on the possibility for versatile organization of original secondary building units (SBUs) able to self-assemble into predicted structural edifices. Single-crystal and powder XRD versus temperature, high-temperature (31)P NMR, as well as transmission electron microscopy were used for structural characterization. Preliminary electric characterization is also reported.     

Syntheses,Characterization, and Fluorescence Properties of Four Coordination Polymers based on Double Betaine Ligands

Four novel In³⁺ and Cd²⁺ based 1D coordination compounds constructed by double betaine ligands were synthesized and characterized structurally and optically. They assemble into 3D supra‐molecular architectures via different stacking or entanglement of 1D zigzag shaped chains, in which C–H ··· Cl and C–H ··· O hydrogen bonding interactions play a dramatic impact. Compound 1 displays a 1D + 1D → 3D four‐connect lvt net with 4² · 8⁴ topology. Compound 2 assembles into a 3D architecture by inclined stacking of the adjacent zigzag chains. Compound 3 displays a 2D + 2D → 3D inclined polycatenation based on the resulting 2D (6, 3) layers that constructed by 1D chains. Compound 4 displays a 3D supra‐molecular architecture based on 1D chains, which were connected via the hydrogen bonding. Meanwhile, four compounds emit in the range of visible region owing to the intra‐ligand π*→π and/or π*→n electron transition induced florescence.