Magnetic Fe3O4 nanoparticles have attached attention in bone tissue engineering because of their superior magnetism and great biocompatibility. However, some disadvantages such as the potential risk of agglomeration impair their applications. Here, we proposed a hybrid magnetic nanocomposite microgel by the integration of Fe3O4 nanoparticles and digital lighting processing (DLP) three-dimensional (3D) printing technology. The 3D-printed microgels could be precisely customized by printing the mixture of gelatin methacryloyl (GelMA) solution and polydopamine-coated Fe3O4 nanoparticles, in which polydopamine decoration improved the hydrophilicity and distribution of the incorporated Fe3O4. The degradable microgels could be injected through a 22-G needle while retaining their original shape after injection. Interestingly, the addition of Fe3O4 nanoparticles into GelMA solution displayed improved printing accuracy. Moreover, these magnetic microgels were biocompatible in vitro and in vivo. After induction within osteogenic medium, addition of nanoparticles upregulated the osteogenic gene expression of rat bone mesenchymal stem cells (BMSCs). In a word, this work provides a magnetic microplatform, which shows great potential in bone tissue engineering. 相似文献
A reactive cyclodextrin was synthesised by reacting β‐cyclodextrin with itaconic acid to enable it to fix permanently onto cellulosic materials. Because synthesis is a complicated process that is greatly influenced by many factors, the response surface methodology was applied in this study to optimise production. To investigate the efficiency of the esterification reaction, the amount of carboxyl groups and the double bond content of the end product were measured and employed as the responses. The 3D response surface plots and the contour plots derived from the mathematical models were applied to evaluate the interactive effects of parameters affecting the reaction, such as itaconic acid and catalyst concentrations, material to liquor ratio, temperature and time of reaction. The amount of carboxyl groups and the double bond content of cyclodextrin itaconate (about 175 and 150 meq./100 g CDI, respectively) in the optimum conditions indicated that one to two itaconic acid molecules could react with cyclodextrin according to the esterification reaction. In addition, the presence of the new supplementary groups on cyclodextrin could effect on the aggregation behaviour of this new cyclodextrin derivative as demonstrated by dynamic light scattering and AFM. 相似文献
At pH = 8, the complex formation process of Ni（Ⅱ） ions with FA was studied by the solubility method. FA were separated from the river Mtkvari by the adsorption-chromotographic method. The charcoal （BAU, Russia） was used as a sorbent. The old suspension of Ni（Ⅱ） hydroxide was used as the solid phase, on which was added the increasing quantity of standard solution of FA. In diluted solutions, at pH = 8.0 the dominant form of Ni（Ⅱ） is nickel dihydroxocomplex Ni（OH）2^0. It was established that in the Ni（OH）2（solid）-Ni（OH）2^0（solution）-FA2-H20 system dominates nickel dyhydroxofulvate complex with the structure 1：1, [Ni（OH）2FA]2-. The average stability constant of nickel dyhydroxofulvate complex was calculated based on experimental data flNi（OH）2FA2＂ = 5.3 × 105. 相似文献
The acyloxy group of 2‐acyloxy‐2H‐azirines has been displaced by carboxylic acids to generate the corresponding 2‐acyloxy‐2H‐azirines by using potassium iodide as a promotor. This metal‐free method can be performed with a wide scope of substrates readily generating products in moderate to high yields. It also represents an example of nucleophilic substitution between esters and carboxylic acids under metal‐free reaction conditions for the first time.
Green synthesis of nanoparticles is superior to physical and chemical methods as it is environment‐friendly and cost‐effective. The present study was carried out for inducing nanoparticles synthesis by zinc nitrate in the leaves extracts of olive. Further leaves extracts were evaluated for antiradical scavenging activity by 1, 1‐diphenyl‐2‐picryl‐hydrazyl assay. Morphological and structural properties of the synthesised ZnO nanoparticles have been characterised using UV‐Vis spectrophotometer, FTIR, TEM, XRD and dynamic light scattering (DLS) analysis. Further, zinc oxide nanoparticles were evaluated for antiradical scavenging activity by capacity of total antioxidant assay. Synthesised ZnO nanoparticles were confirmed by the absorption maxima at the wavelength of 370 nm. TEM image revealed that ZnO nanoparticles were spherical with average size 41 nm. FTIR investigation suggested that the flavonoids, glycosides, proteins and phenols molecules can play an important role in the stabilisation of ZnO nanoparticles.Inspec keywords: zinc compounds, II‐VI semiconductors, wide band gap semiconductors, nanoparticles, nanofabrication, ultraviolet spectra, visible spectra, Fourier transform infrared spectra, transmission electron microscopy, X‐ray diffraction, light scatteringOther keywords: zinc oxide nanoparticles, green synthesis, physical method, chemical method, zinc nitrate, antiradical scavenging activity, 1, 1‐diphenyl‐2‐picryl‐hydrazyl assay, morphological properties, structural properties, UV‐vis spectrophotometer, FTIR, TEM, XRD, dynamic light scattering analysis, flavonoids, glycosides, proteins, phenols molecules, Olea europaea, ZnO相似文献
The interaction between nanoparticles and plants is inevitable. In this study, the effect of different concentrations of ZnO nanoparticles synthesised using olive extract on the soybean was studied. The soybean seeds were cultured in a Hoagland medium containing agar which was treated different concentrations (0, 200 and 400 ppm) of ZnO nanoparticles. After 21 days, the plants were harvested and the parameters of proline, anthocyanin, malondialdehyde (MDA), hydrogen peroxide (H2 O2), chlorophyll and carotenoid contents and phenylalanine ammonia‐lyase (PAL) and catalase (CAT) activity in soybeans (Glycine max) were measured. The results showed that the levels of chlorophyll a and b and carotenoid at concentrations of 200 and 400 ppm in comparison with control decreased, while carotenoid content at 200 ppm concentration at a concentration of 400 ppm was not significant. The level of anthocyanin and PAL activity increased with increasing concentration of nanoparticles, while proline content decreased. By increasing the concentration of ZnO nanoparticles, the content of MDA and hydrogen peroxide increased compared to control but CAT activity did not change significantly. This research suggests that ZnO nanoparticles synthesised using olive extract in soybean plants may be toxic by reactive oxygen species production.Inspec keywords: crops, pigments, enzymes, nanoparticles, zinc compounds, toxicology, agricultural safety, nanobiotechnology, hydrogen compoundsOther keywords: carotenoid content, proline content, ZnO nanoparticles, soybean plants, H2 O2 , ZnO, time 21.0 d, reactive oxygen species production, toxicity, catalase activity, phenylalanine ammonia‐lyase activity, chlorophyll content, Hoagland medium, olive extract, lipid peroxidation, photosynthetic pigments, hydrogen peroxide, anthocyanin contents相似文献
The visible–near infrared (VNIR) and short wave infrared (SWIR) spectral bands of both the level 1B, radiance at sensor, and level 2, AST_07 surface reflectance data products of the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) instrument were evaluated and compared for mapping the alteration zones around porphyry copper deposits and occurrences at the northern Shahr‐e‐Babak, SE Iran. The level 1B data were converted to reflectance using internal average relative reflectance (IARR) method whereas the AST_07 dataset was processed as delivered. The porphyry copper mineralization occurs in Eocene, andesitic and basaltic rocks with zonal alteration patterns that are concentric and almost symmetrically arranged. The spectral signatures of alteration index minerals collected from field samples and the United States Geological Survey (USGS) spectral reference library, were considered in directed principal component analysis (DPCA) and spectral angle mapping (SAM) algorithms. Carrying out the DPCA method on three spectral bands enhanced the alteration haloes in the last principal component (PC) images. Generating RGB colour composite images using these PC images differentiated three alteration zones from the host rocks. The SAM results of the IARR calibrated dataset discriminated the propylitic, argillic and phyllic alteration zones. It is concluded that the higher spectral resolution of ASTER instrument is effective for mineral mapping. However, the method of conversion from radiance to reflectance is critical to the validity of the outputs and that the pseudo‐reflectance method using the IARR process may be more reliable than the standard reflectance product. 相似文献
