ABSTRACT
Recent global scientific attention has been directed towards eco-friendly synthesis and versatile applications of silver nanoparticles (AgNPs) due to their effectiveness against specific cells and tissues. This study aimed to develop a green synthesis method for AgNPs using ethanolic extract from Salvia sclarea aerial parts, and to assess their protective efficacy against streptozotocin (STZ)-induced diabetic nephropathy in rats. Additionally, antioxidant, anti-inflammatory, and apoptosis studies were conducted to understand their mode of action. Characterization via ultraviolet-visible (UV-Vis) spectroscopy, infrared (IR) spectroscopy, and X-ray diffraction (XRD) confirmed the formation of ethanol extract of Salvia sclarea silver nanoparticles (EESS AgNPs), with a distinctive absorption peak at 400 nm. Scanning electron microscopy (SEM) analysis revealed predominantly spherical and quasi-spherical shapes of the synthesized nanoparticles. The treatment procedure spanned for a period of 12 weeks in diabetic rats and were evaluated for inflammatory markers (tumor necrosis factor-α, antioxidant markers (superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and glutathione (GSH) and apoptosis markers (Bcl-2, Bax, cleaved-caspase-3). Results demonstrated that treatment with EESS AgNPs significantly reduced blood glucose levels compared to the diabetic group. Additionally, EESS AgNPs treatment led to a significant decrease in levels of pro-inflammatory cytokines TNF-α, IL-1ß, and PKC-êµ in renal cells. Furthermore, EESS AgNPs effectively modulated antioxidant enzyme concentrations, including GSH, SOD, GPx, and CAT, bringing them to acceptable levels. Administration of EESS AgNPs also resulted in a significant decrease in protein levels of Bax and activated caspase-3, while increasing expression of the anti-apoptotic protein Bcl-2 in renal cells of STZ-induced diabetic rats. In conclusion, EESS AgNPs demonstrate potent anti-hyperglycemic effects, potentially mitigating diabetic nephropathy by suppressing hyperglycemiainduced oxidative stress, apoptosis, and inflammation in renal cells of diabetic rats.
Subject(s)
Anti-Inflammatory Agents , Antioxidants , Apoptosis , Diabetes Mellitus, Experimental , Diabetic Nephropathies , Ethanol , Green Chemistry Technology , Metal Nanoparticles , Plant Extracts , Salvia , Silver , Streptozocin , Animals , Apoptosis/drug effects , Diabetic Nephropathies/drug therapy , Diabetic Nephropathies/prevention & control , Diabetic Nephropathies/metabolism , Diabetic Nephropathies/pathology , Antioxidants/pharmacology , Salvia/chemistry , Plant Extracts/pharmacology , Silver/chemistry , Anti-Inflammatory Agents/pharmacology , Male , Diabetes Mellitus, Experimental/drug therapy , Rats , Rats, Wistar , Oxidative Stress/drug effectsABSTRACT
Liquid coordination complexes (LCCs), which are formed between metal halides and donor molecules, represent promising catalysts. Six amide-AlCl3 LCCs were successfully synthesized, followed by their characterization through NMR, Raman, and UV-visible spectroscopy. The acidity of these LCCs was quantified by performing computational modelling of fluoride ion affinities (FIA) and experimental Gutmann-Beckett measurements. Spectroscopic analysis indicated bidentate coordination between amide ligands and Al, which induced asymmetric splitting of Al2Cl6 into diverse ions such as [AlCl2L2]+, [AlCl4]-, [AlCl3L], and [Al2Cl6L]. The computed FIA was found to align well with the experimental acidity trends, thereby confirming the proposed structure of the LCC. In the alkylation tests, the LCC with a high acidity demonstrated an increase in the yields of C5-C7 alkylates. These results provide an in-depth understanding of the tuneable structures of amide-AlCl3 LCCs. The acidity of LCCs can be controlled by tuning the ratio of the organic ligand to AlCl3, which allows bidentate coordination to facilitate asymmetric splitting of Al2Cl6. The LCCs demonstrate a high degree of potential as versatile and sustainable acid catalysts in alkylation reactions. These findings may advance the foundational knowledge of LCCs for the purpose of targeted acid catalyst design.
ABSTRACT
SiO2@GdPO4:Tb@SiO2 nanoparticles with core-shell-shell structure were successfully synthesized by a cheap silane coupling agent grafting method at room temperature. This method not only homogeneously coated rare-earth phosphate nanoparticles on the surface of silica spheres but also saved the use of rare-earth resources. The obtained nanoparticles consisted of SiO2 core with a diameter of approximately 210 nm, GdPO4:Tb intermediate shell with thickness of approximately 7 nm, and SiO2 outer shell with thickness of approximately 20 nm. This unique core-shell-shell structured nanoparticles exhibited strong luminescence properties compared with GdPO4:Tb nanoparticles. The core-shell-shell structured nanoparticles can effectively quench the intrinsic fluorescence of bovine serum albumin through a static quenching mode. The as-synthesized nanoparticles show great potential in biological cell imaging and cancer treatment.
ABSTRACT
Two novel core-shell structured SiO2@AIPA-S-Si-Eu and SiO2@AIPA-S-Si-Eu-phen nanocomposites have been synthesized by a bifunctional organic ligands ((HOOC)2C6H3NHCONH(CH2)3Si(OCH2CH3)3) (defined as AIPA-S-Si) connected with Eu3+ ions and silica via covalent bond. And the corresponding core-shell-shell structured SiO2@AIPA-S-Si-Eu@SiO2 and SiO2@AIPA-S-Si-Eu-phen@SiO2 nanocomposites with enhanced luminescence have been synthesized by tetraethyl orthosilicate (TEOS) hydrolysis co-deposition method. The composition and micromorphology of the nanocomposites were characterized by means of Fourier-transform infrared spectroscopy (FT-IR), thermal gravimetric analysis (TG), X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive X-ray spectrometry (EDX) and X-ray photoelectron spectroscopy (XPS). The as-synthesized core-shell and core-shell-shell structured nanocomposites have excellent luminescence intensity and long lifetime. The nanocomposites show bright red light under ultraviolet lamp. However, the core-shell-shell structured nanocomposites have stronger luminescence intensity than the corresponding core-shell structured nanocomposites. Meanwhile, the core-shell-shell structured nanocomposites still exhibit good luminescence stability in aqueous solution. In addition, a large number of Si-OH on the surface of the core-shell-shell structured nanocomposites can be attached to many biomacromolecules. Therefore, they have potential applications in the fields of biology and luminescence.
ABSTRACT
Four core-shell structured nanometre luminescent composites with different kernel sizes and different shell layer thicknesses (SiO2(500) @Eu (phen-Si)(50) , SiO2(500) @Eu (phen-Si)(15) , SiO2(250) @Eu (phen-Si)(5) and SiO2(250) @Eu (phen-Si)(10) ) were made by changing synthesis conditions. Here, initial subscript numbers in parentheses refer to the particle size of the SiO2 core, whereas the final subscript numbers in parentheses refer to shell layer thickness. In these composites, silica spheres of 500 nm or 250 nm were identified as the core. The shell layer was composited of silicon, 1,10-phenanthroline and europium perchlorate, abbreviated as Eu(phen-Si); the chemical formula of phen-Si was phen-N-(CONH (CH2 )Si(OCH2 CH3 )3 )2 . The composites were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and infrared spectroscopy. The monodispersed spherical SiO2 showed characteristics of a regular microstructure and a smooth surface, as well as the advantage of dispersity, shown by SEM. The Eu(phen-Si) complex was able to self-assemble into monodispersed SiO2 spheres, as seen using TEM. Fluorescence spectra indicated that the four composites had excellent luminescence properties. Furthermore, composites composed of a SiO2 core and a 250 nm kernel size exhibited stronger fluorescence than 500 nm kernel-sized composites. Fluorescence properties were affected by shell thickness: the thicker the shell, the greater the fluorescence intensity. For the four composites, quantum yield values and fluorescence lifetime corresponded to fluorescence emission intensity data as quantum yield values and fluorescence lifetime were higher, and luminescence properties increased.
Subject(s)
Coordination Complexes/chemistry , Europium/chemistry , Luminescent Agents/chemistry , Nanospheres/chemistry , Organosilicon Compounds/chemistry , Silicon Dioxide/chemistry , Coordination Complexes/chemical synthesis , Luminescent Agents/chemical synthesis , Molecular Structure , Particle Size , Surface PropertiesABSTRACT
Three novel core-shell nanostructured composites SiO2@ANA-Si-Tb, SiO2@ANA-Si-Tb-L (L = second ligand) with SiO2 as the core and terbium organic complex as the shell were successfully synthesized. The core and shell were connected together by covalent bonds. The terbium ion was coordinated with organic ligand-forming terbium organic complex in the shell layer. The organosilane (HOOCC5H4NN(CONH(CH2)3Si(OCH2CH3)3)2 (abbreviated as ANA-Si) was used as the first ligand and 1,10-phenanthroline (phen) or 2-thenoyltrifluoroacetone (TTA) was used as the second ligand. Furthermore, silica-modified SiO2@ANA-Si-Tb@SiO2, SiO2@ANA-Si-Tb-L@SiO2 core-shell-shell nanostructured composites were also synthesized by sol-gel chemical route, which involved the hydrolysis and polycondensation processes of tetraethoxysilane (TEOS) using cetyltrimethyl ammonium bromide (CTAB) as a surface-active agent. An amorphous silica shell was coated around the SiO2@ANA-Si-Tb, SiO2@ANA-Si-Tb-L core-shell nanostructured composites. The core-shell and core-shell-shell nanostructured composites exhibited excellent luminescence in the solid state. Meanwhile, an improved luminescent stability property of the core-shell-shell nanostructured composites was observed for the aqueous solution. This type of core-shell-shell nanostructured composites exhibited bright luminescence, high stability and good solubility, which may present potential applications in the fields of optoelectronic devices, bio-imaging, medical diagnosis and study on the structure of function composite materials.
ABSTRACT
The novel submicro-spheres SiO2@LaPO4:Eu@SiO2 with core-shell-shell structures were prepared by connecting the SiO2 submicro-spheres and the rare earth ions through an organosilane HOOCC6H4N(CONH(CH2)3Si(OCH2CH3)3 (MABA-Si). The as-prepared products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and infrared spectroscopy (IR). It is found that the intermediate shell of the submicro-spheres was composed by LaPO4:Eu nanoparticles with the size of about 4, 5-7, or 15-34 nm. A possible formation mechanism for the SiO2@LaPO4:Eu@SiO2 submicro-spheres has been proposed. The dependence of the photoluminescence intensity on the size of the LaPO4:Eu nanoparticles has been investigated. The intensity ratios of electrical dipole transition 5D0 â 7F2 to magnetic dipole transition 5D0 â 7F1 of Eu3+ ions were increased with decreasing the size of LaPO4:Eu nanoparticles. According to the Judd-Ofelt (J-O) theory, when the size of LaPO4:Eu nanoparticles was about 4, 5-7 and 15-34 nm, the calculated J-O parameter Ω2 (optical transition intensity parameter) was 2.30 × 10-20, 1.80 × 10-20 and 1.20 × 10-20, respectively. The increase of Ω2 indicates that the symmetry of Eu3+ in the LaPO4 lattice was gradually reduced. The photoluminescence intensity of the SiO2@LaPO4:Eu@SiO2 submicro-spheres was unquenched in aqueous solution even after 15 days.
ABSTRACT
Two novel core-shell composites SiO2@PMDA-Si-Tb, SiO2@PMDA-Si-Tb-phen with SiO2 as the core and terbium organic complex as the shell, were successfully synthesized. The terbium ion was coordinated with organic ligand forming terbium organic complex in the shell layer. The bi-functional organosilane ((HOOC)2C6H2(CONH(CH2)3Si(OCH2CH3)3)2 (abbreviated as PMDA-Si) was used as the first ligand and phen as the second ligand. Furthermore, the silica-modified SiO2@PMDA-Si-Tb@SiO2 and SiO2@PMDA-Si-Tb-phen@SiO2 core-shell-shell composites were also synthesized by sol-gel chemical route. An amorphous silica shell was coated around the SiO2@PMDA-Si-Tb and SiO2@PMDA-Si-Tb-phen core-shell composites. The core-shell and core-shell-shell composites both exhibited excellent luminescence in solid state. The luminescence of core-shell-shell composites was stronger than that of core-shell composites. Meanwhile, an improved luminescence stability property for the core-shell-shell composites was found in the aqueous solution. The core-shell-shell composites exhibited bright luminescence, high stability, long lifetime, and good solubility, which may present potential applications in the bio-medical field.
ABSTRACT
Two novel core-shell structure ternary terbium composites SiO2(600)@Tb(MABA-Si)·L(L:dipy/phen) nanometre luminescence materials were prepared by ternary terbium complexes Tb(MABA-Si)·L2·(ClO4)3·2H2O shell grafted onto the surface of SiO2 microspheres. And corresponding ternary terbium complexes were synthesized using (CONH(CH2)3Si(OCH2CH3)3)2 (denoted as MABA-Si) as first ligand and L as second ligand coordinated with terbium perchlorate. The as-synthesized products were characterized by means of IR spectra, 1HNMR, element analysis, molar conductivity, SEM and TEM. It was found that the first ligand MABA-Si of terbium ternary complex hydrolysed to generate the Si-OH and the Si-OH condensate with the Si-OH on the surface of SiO2 microspheres; then ligand MABA-Si grafted onto the surface of SiO2 microspheres. The diameter of SiO2 core of SiO2(600)@Tb(MABA-Si)·L was approximately 600 nm. Interestingly, the luminescence properties demonstrate that the two core-shell structure ternary terbium composites SiO2(600)Tb(MABA-Si)·L(dipy/phen) exhibit strong emission intensities, which are 2.49 and 3.35 times higher than that of the corresponding complexes Tb(MABA-Si)·L2·(ClO4)3·2H2O, respectively. Luminescence decay curves show that core-shell structure ternary terbium composites have longer lifetime. Excellent luminescence properties enable the core-shell materials to have potential applications in medicine, industry, luminescent fibres and various biomaterials fields.
ABSTRACT
The hexagonal and monoclinic phase LaPO4 and LaPO4:Eu nanostructures have been controllably synthesized by a citrate-induced hydrothermal process at 100 °C. The crystal growth of LaPO4 nanostructures was investigated, and the phase transformation of nanostructured LaPO4 was systematically studied by varying the citrate concentration, pH value and reaction temperature. When 0.8 mmol of citrate was added into the reaction system, the hexagonal phase LaPO4 transformed into the monoclinic phase. High concentrations of citrate would lead to the formation of hexagonal phase LaPO4. The photoluminescence properties of the monoclinic phase LaPO4:Eu prepared using a citrate-induced process demonstrate that the electric dipole transition (5D0 â 7F2) is stronger than the magnetic dipole transition (5D0 â 7F1), which indicated that Eu3+ is in a site with no inversion center. The strongest emission peak of hexagonal phase LaPO4:Eu comes from 5D0 â 7F1. Furthermore, the citrate-induced hexagonal phase LaPO4:Eu has a stronger emission intensity than the hexagonal phase LaPO4:Eu prepared not using a citrate-induced process.
ABSTRACT
This article reports a novel category of coating structure SiO2 @Eu(MABA-Si) luminescence nanoparticles (NPs) consisting of a unique organic shell, composed of perchlorate europium(III) complex, and an inorganic core, composed of silica. The binary complex Eu(MABA-Si)3 ·(ClO4 )3 ·5H2 O was synthesized using HOOCC6 H4 N(CONH(CH2 )3 Si(OCH2 CH3 )3 )2 (MABA-Si) and was used as a ligand. Furthermore, the as-prepared silica NPs were successfully coated with the -Si(OCH2 CH3 )3 group of MABA-Si to form Si-O-Si chemical bonds by means of the hydrolyzation of MABA-Si. The binary complexes were characterized by elemental analysis, molar conductivity and coordination titration analysis. The results indicated that the composition of the binary complex was Eu(MABA-Si)3 ·(ClO4 )3 ·5H2 O. Coating structure SiO2 @Eu(MABA-Si) NPs were characterized using transmission electron microscopy (TEM), scanning electron microscopy (SEM) and infrared (IR) spectra. Based on the SEM and TEM measurements, the diameter of core-SiO2 particles was ~400 and 600 nm, and the thickness of the cladding layer Eu(MABA-Si) was ~20 nm. In the binary complex Eu(MABA-Si)3 ·(ClO4 )3 ·5H2 O, the fluorescence spectra illustrated that the energy of the ligand MABA-Si transferred to the energy level for the excitation state of europium(III) ion. Coating structure SiO2 @Eu(MABA-Si) NPs exhibited intense red luminescence compared with the binary complex. The fluorescence lifetime and fluorescence quantum efficiency of the binary complex and of the coating structure NPs were also calculated. The way in which the size of core-SiO2 spheres influences the luminescence was also studied. Moreover, the luminescent mechanisms of the complex were studied and explained.
Subject(s)
Europium/chemistry , Luminescence , Nanoparticles/chemistry , Organometallic Compounds/chemistry , Organometallic Compounds/chemical synthesis , Organosilicon Compounds/chemistry , Particle Size , Perchlorates/chemistry , Surface PropertiesABSTRACT
Tb(3+)-doped CePO4 flower-like clusters were hydrothermally synthesized without using any template or surfactant by varying the reactant Tb3+ cation concentration. It was observed that the flower-like clusters were composed by nanowires with a diameter of about 80-90 nm and lengths up to 1 microm. The structures, morphologies, sizes and luminescence properties of the products were studied by X-ray powder diffraction (XRD), field-emission scanning electronic microscopy (FE-SEM), and luminescence spectra. With the reactant Ce3+ /Tb3+ molar ratio of 0.850 : 0.150, the uniform flower-like clusters were actually composed of a self-assembly of the oriented nanowires through an Tb(3+)-induced in the excessive PO4(3-). It was found that the reactant Ce3+/Tb3+ molar ratio and phosphoric acid played key roles in the morphology control of the product. A possible formation mechanism for the flower-like morphology was also proposed. The luminescence properties of CePO4 : Tb flower-like cluster were performed, indicating that the strongest emission intensity was reached with 0.850 : 0.150 molar ratios of Ce3+/Tb3+.
ABSTRACT
The nanostructured CePO4 with monoclinic phase was controllably synthesized through a low temperature hydrothermal route by varying the reactant PO4(3-)/Ce(3+) molar ratio. The structures, morphologies, sizes and luminescence properties of the products were studied by XRD, FE-SEM, DSC-TG and photoluminescence spectra. With the PO4(3-)/Ce(3+) molar ratios increased, the synthesis temperature of as-synthesized monoclinic CePO4 was decreased, and the morphologies underwent the evolution from the rod-like nano-structures to the flower-like nanoclusters. When the PO4(3-)/Ce(3+) molar ratio was lower, CePO4 nanorods were obtained, while the PO4(3-)/Ce(3+) molar ratio was higher, the monoclinic CePO4 flower-like nanoclusters were crystallized. The photoluminescence spectrum showed that the CePO4 nanorods exhibit better photoluminescent property than the CePO4 flower-like nanoclusters. With the cycling use of phosphoric acid, the low-cost preparation of CePO4 could be achieved.
ABSTRACT
Seven solid complexes of proportional mixed complexes (Eu3+ mixed with La3+) of rare earth perchlorate with the 2-thiophene carboxylic acid and 1.10-phenanthroline were synthesized. By elemental analysis, coordination titration and molar conductance measurement, the composition of the complexes were suggested to be (Eu(1-x)La(x)) x L3 x phen x 1/2H2O (x = 0.000-0.200, L as 2-thiophene carboxylic acid and phen for 1.10-phenanthroline) respectively. The ligands and coordination compounds were studied by means of IR spectra and fluorescence excitation and emission spectra. The molar conductivities in DMF solvent suggested that the complexes are nonelectrolyte. IR spectra studies indicate that the 2-thiophene carboxylic acid ligands bonded with RE(II) through oxygen atoms in carboxyl group and 1.10-phenanthroline ligand is bonded to RE(III) through nitrogen atoms. In the fluorescence spectra it was found that the Eu3+ complex has no symmetrical center. La3+ has a great influence on the luminescence of Eu3+. The fluorescence emission intensity of Eu3+ was enhanced by La3+ and the fluorescence intensity with x = 0.050 is much higher. With La3+ concentration increasing the luminescence of Eu3+ is less intense.
Subject(s)
Europium/chemistry , Lanthanum/chemistry , Luminescent Measurements/methods , Organometallic Compounds/analysis , Spectroscopy, Fourier Transform Infrared/methods , Cations/chemistry , Organometallic Compounds/chemistryABSTRACT
Two binary complexes of Eu3+ and Tb3+ with 2-thiophene carboxylic acid and two ternary complexes of Eu3+ and Tb3+ with 2-thiophene carboxylic acid(L)-2, 2'-bipyridine were synthesized. By elemental analysis, rare earth coordination titration, and molar conductivities studies, the compositions of the complexes were suggested as REL3 x 2H2O and REL3L' x C2H5OH(RE=Eu, Tb, L = 2-thiophene carboxylic acid, L' = 2, 2'-bipyridine) respectively. The ligands and coordination compounds were studied by means of IR spectra, 1H NMR and fluorescence excitation and emission spectra. IR spectra and 1H NMR studies indicate that 2-thiophene carboxylic acid was bonded with RE(III) through oxygen atoms in the carboxyl group, and 2, 2'-bipyridine ligand was bonded to RE(III) through nitrogen atoms. The fluoresence spectra showed that the fluorescence emission intensity of ternary complexes was stronger than that of the binary complexes.