A new series of rare earth bismuth silicates has been synthesized by flux method and solid state reaction . LnBiSiO 5 (Ln = Ce, Tb) crystallizes in a triclinic space group P -1 with cell parameters a = 5.6763(2) Å, α = 105.591(3)° b = 6.7922(3) Å, β = 110.551(3)° c = 6.9593(2) Å, γ = 99.733(3)°, Z = 2. They exhibit a novel three-dimensional structure consisting of zig-zag chains of edge-sharing Ce/TbO 8 polyhedra that are further linked by SiO 4 units and Bi 2 O 8 clusters. The optical band gap (E g ) of TbBiSiO 5 was estimated to be 3.84 eV from UV–Vis-IR diffuse reflectance spectra. Photoluminescence measurements suggest that due to the cooperative interaction of Bi and Tb the excitation bands monitored at 544 nm are shifted towards longer wavelength which may favor commercial UV diode excitation. The magnetic measurements show that TbBiSiO 5 exhibits paramagnetic behavior without magnetic transitions down to 1.8 K.
Development of sustainable biomaterials from wasted resources has been widely advocated recently. In this study, chitin was extracted from Hericium erinaceus residues and used as the main framework to in situ synthesize series of magnetic chitin hydrogels for Cu 2+ removal. Results showed that the extracted chitin with 1.56 × 10 5 g/mol molecular weight and 51.83% degree of acetylation was completely composed of glucosamine. After introduction of Fe 3 O 4 particles, the magnetic chitin hydrogels exhibited preferable adsorption capacity for Cu 2+ than its native form. Besides, the magnetic chitin hydrogels showed paramagnetic behavior and improved mechanical property but the slight reduced swelling and thermal performance. Moreover, the swelling, mechanical, magnetic and adsorption properties were found to be Fe 3 O 4 content-dependent, indicating its specific tunable performance. Therefore, this work provided a new alternative renewable resource for chitin and facile procedure to prepare magnetic chitin hydrogels as a promising candidate material for heavy metal removal system.
Magnetic mesoporous nanocomposites are emerging as a significant new material to improve the effectiveness of cancer treatment and enhance the availability of drug therapy. Thus, the core–shell structure magnetic mesoporous nanocomposites (Fe 3 O 4 @SiO 2 @LDH) were synthesized with an average diameter of about 100 nm and used as methotrexate (MTX) carriers for cancer therapy. As an important biological material, Fe 3 O 4 @SiO 2 @LDH exhibited higher superparamagnetic behavior and biocompatibility, and the drugs can be loaded in the channels of the mesoporous silica and the interlayer of layered double hydroxides (LDH). The embedding rate of magnetic mesoporous silica (Fe 3 O 4 @SiO 2 ) and LDH were 60.32 % and 0.67 %, respectively, and the release rate of the drug delivery systems (Fe 3 O 4 @SiO 2 @LDH-MTX) was 66.81 %. In addition, LDH as a kind of pH-sensitive material was adopted for controlled drug release and WST-1 assays in cancer cells (Hela) demonstrated that Fe 3 O 4 @SiO 2 @LDH-MTX presented high anti-tumor activity, while the carriers were nearly non-toxic. Therefore, all the results suggested that the magnetic nanocomposites can be employed to deliver MTX, and would be applied in the field of cancer therapy in the future.
Yi Teng,Shu Wu,Xia Chen,Lu Bai,Qiuhua Wu,Guolin Zhang
New magnetic yolk-shell mesoporous silica nanoparticles (Fe3O4@V-mSiO2-PNVCL) were prepared by grafting temperature-sensitive amino-terminated poly (N-vinylcaprolactam) (PNVCL-NH2) on the surface of aldehyde-functionalized magnetic mesoporous silica nanoparticles (Fe3O4@V-mSiO2-CHO) through a Schiff base reaction. Various characterizations were used to confirm the structures, and the drug loading and release behaviors were studied. The drug loading was achieved as PNVCL stretched at room temperature and the drug loading content was up to 54.7% due to the large cavities. The encapsulation of drug from leakage in the blood environment was realized as PNVCL collapsed at physiological temperature. The fracture of pH-liable imine bonds in a slightly acidic tumor environment triggered the burst release of cargo. The Fe3O4@V-mSiO2-PNVCL showed super paramagnetic behavior (21.01 emu∙g−1) which could achieve magnetic targeting. The MTT assay confirmed that the nanoparticles exhibited low cytotoxicity. Furthermore, the cellular uptake experiments indicated that DOX-loaded nanoparticles were successfully internalized into cancer cells. Therefore, the composite nanoparticles are ideal choices for drug carriers.
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