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1.
Single-crystalline gold microplates of several 10 microm in lateral size, characterized by hexagonal, truncated triangular, and triangular shapes with (111) planes as two basal surfaces, have been synthesized in large quantities through a solution phase process. Significantly, such anisotropic Au nanostructures exhibit remarkable optical properties, in which the dipole plasmon resonance shifting in the NIR region and the quadrupole plasmon resonance at approximately 820 nm were observed. Fragmentation of Au microplates is found when the temperature is higher than 450 degrees C, indicating they are not thermodynamically stable structure at high temperature. Investigations on the Au microplates upon heating suggest that the melting and collapsing start mainly at the edges that should be Au (110) facets. This work is valuable for Au nanostructures applied at elevated temperatures. 相似文献
2.
《应用有机金属化学》2017,31(9)
Gold nanoparticles (AuNPs) were synthesized by reduction of chloroauric acid (HAuCl4) aqueous solution with hydrazine monohydrate. The AuNPs were immediately treated with cysteamine to obtain amine‐functionalized nanoparticles (Au‐NH2). The reaction of Au‐NH2 with epichlorohydrin and subsequent treatment with sodium hydroxide gave epoxidized AuNPs (Au‐EP). Then, thiol‐capped AuNPs (Au‐SH) were synthesized by reaction of Au‐EP with cysteamine. A ‘grafting to’ approach was utilized to graft bromine‐terminated poly(N ,N ′‐dimethylaminoethyl methacrylate), synthesized via aqueous atom transfer radical polymerization, with various molecular weights (6280, 25 800, 64 200 and 87 600 g mol−1) onto Au‐SH to obtain Au‐P1, Au‐P2, Au‐P3 and Au‐P4 samples, respectively. All samples were exposed to temperature and pH variations, and Z‐average diameter was monitored using dynamic light scattering. According to the results, polymer‐grafted nanoparticles collapsed at lower temperatures with increasing solution pH for all molecular weight ranges due to deprotonation of tertiary amine groups. However, higher molecular weight polymers were more sensitive to pH variation especially in alkaline media. Also, a high degree of agglomeration was observed for Au‐P4 nanoparticles in alkaline media on increasing the temperature to 55 and 65 °C. 相似文献
3.
Hamed Nosrati Soodabeh Davaran Hamidreza Kheiri Manjili Hamed Rezaeejam Hossein Danafar 《应用有机金属化学》2019,33(10)
In this time researchers make a great efforts to develop new hybrid nanoparticles for medical and pharmaceutical applications. Fe3O4‐Au hybrid heterodimers have been prepared with superior properties for various claims. Unfortunately, Fe3O4‐Au heterodimers are not stable in the physiological medium. In this study, we employed the albumin macromolecules as a stabilizer of Fe3O4‐Au hybrid nanoparticles (noted as Fe3O4‐Au‐BSA hybrid nanoparticles). After characterization of synthesized nanoparticles by FTIR, UV–Vis, TEM, DLS, DSC, VSM and XRD techniques, the in vitro and in vivo biocompatibility of these nanoparticles were also evaluated. We encountered with an amazing result which confirmed nanoparticles could be stabilized by linking the BSA on the surface of Fe3O4‐Au heterodimers. Also, intravenous injection of Fe3O4‐Au‐BSA hybrid nanoparticles up to 400 mg/kg to Balb C mice show that these nanoparticles were non‐toxic. The biocompatibility and stereological study had been performed for more than 30 days after nanoparticles administration, using hystomorphometric analysis. Remarkably, to the best of our knowledge, it was the first time the biocompatibility and biodegradability of Fe3O4‐Au were studied and evaluated by stereological technique. Further promotion and biomedical usage of this type of hybrid nanoparticles are underway in our laboratory. 相似文献
4.
Cong Yu Fangjie Wo Yuxiang Shao Xiangyun Dai Maoquan Chu 《Applied biochemistry and biotechnology》2013,169(5):1566-1578
Gold nanostructures have generated significant attention in biomedical areas because of their major role in cancer photothermal therapeutics. In order to conveniently combine gold nanostructures and drugs into one nanocomposite, Au2Se/Au core–shell nanostructures with strong near-infrared-absorbing properties were synthesized using a simple method and embedded inside bovine serum albumin (BSA) nanospheres by using a spray dryer equipped with an ultrasonic atomizer followed by thermal denaturation. The nanospheres with narrow size distribution mainly ranging from 450 to 600 nm were obtained. The Au2Se/Au-loaded BSA nanospheres (1 mg) adsorbed at least 0.01 mg of water-insoluble zinc phthalocyanine (ZnPc) photosensitizer. After irradiation with a 655-nm laser (20 min), the temperature of the Au2Se/Au-loaded BSA nanospheres [200 μL, 2 mg/mL, BSA/Au2Se/Au 10:1 (w/w)] increased by over 20 °C from the initial temperature of 24.82?±?0.15 °C, and the release of ZnPc was improved compared with a corresponding sample without irradiation. After being incubated with cancer cells (human esophageal carcinoma Eca-109), the nanospheres exhibited photothermal and photodynamic therapy with a synergistic effect upon laser irradiation. This work provides novel Au2Se/Au-loaded polymer nanospheres prepared by a high-efficiency strategy for incorporating drugs for improving the efficiency in killing cancer cells. 相似文献
5.
Synthesis of glyoxalic acid by selective oxidation of glyoxal at ambient temperatures with O2 as an oxidant is an important problem. We found that gold nanoparticles supported on hydrotalcite (Au/HT) exhibit an appreciable catalytic activity for this reaction in the liquid phase. Moreover, Au-Pd/HT, prepared by the deposition-precipitation method is superior in the catalytic behavior to monometallic Au/HT and Pd/HT catalysts. Introduction of palladium enhances ability of the catalysts to oxidize carbonyl to carboxyl, weakens the power to rupture C-C bond and in this way improves the catalytic performance. Furthermore, the Au: Pd ratio also influences the properties of the alloy catalysts. The 1.5Au-1.5Pd/HT catalysts show the highest activity for the selective oxidation at ambient temperature producing glyoxalic acid in 13.4% yield at pH 7.7. Moreover, due to basic properties of hydrotalcite, glyoxalic acid could be synthesized over 1.5Au-1.5Pd/HT in 8.0% yield without adding a base. It is hoped that results of this study can fuel further research in designing new catalysts with alloy nanoparticles supported by hydrotalcite that can be used for the selective oxidation of other useful compounds. 相似文献
6.
Snežana Radisavljević Ana Kesić Dušan Ćoćić Vladimir Marković Jelena Milovanović Biljana Petrović Ana Rilak Simović 《应用有机金属化学》2023,37(1):e6922
In this work we synthesized new monofunctional gold(III) complex [Au(Cl-Ph-tpy)Cl]Cl2 (Cl-Ph-tpy = 4′-[4-chlorophenyl]-2,2′:6′, 2″-terpyridine). This complex was characterized by UV–Vis, NMR, IR, and ESI-MS spectrometry. The kinetic study of the substitution reactions of the Au-Cl-Ph-tpy complex with biomolecules showed that the rate constants depend on the nature of the entering nucleophile. Based on the calculated values of entropy (∆H≠ > 0) and enthalpy (∆S≠ < 0) the proposed substitution mechanism is associative. Additionally, the relative stability and thermodynamic properties of Au-Cl-Ph-tpy complex were compared with the analogue Au-tpy complex by the B3LYP/def2-svp method. DNA/BSA binding studies showed that Au-Cl-Ph-tpy complex interacts with CT DNA through the intercalation and moderately quenches the fluorescence of tryptophan residues in serum albumin (BSA). Molecular docking confirmed results obtained by spectroscopic experiments and suggested site I (subdomain IIA) for binding of Au complex to BSA. We demonstrated that the Au chlorophenyl terpyridine complex possessed significant in vitro cytotoxic activity against human oral squamous carcinoma cells (CAL-27), induced apoptosis, inhibited proliferation of CAL-27 cells, and induced cell cycle disturbance. Treatment of CAL-27 cells with the Au complex enhanced expression of cyclin-dependent kinase inhibitors p21 and p27, resulting in cell cycle arrest in the G1 phase, reduced the percentage of CAL-27 cells in S phase and decreased expression of Ki-67. Additionally, Au complex reduced expression of phosphorylated STAT3 and downstream regulated molecules associated with cancer stemness, NANOG, and Sox2 protein. 相似文献
7.
We have synthesized two types of methoxyphenol thiols, Fc-MP1 and Fc-MP2 to use them in a voltammetric pH sensor. The methoxyphenol group was oxidatively triggered to o-quinone. Thus formed dyad molecules made possible pH measurements based on the pH-dependence of formal potential difference between quinone (pH indicator) and ferrocene (pH reference) moieties. Precise pH measurements over a wide pH range were possible even in a two-electrode mode without a reference electrode. The large polarization effect found in metal counter electrodes such as Au and Pt was removed by simply forming a mixed monolayer using an inert alkanethiol as a diluent. Fc-MP1 and Fc-MP2 were complementary in that Fc-MP2 covers the pH region that was not accessed by Fc-MP1 because of the potential overlap between the Fc+/Fc and Q/H2Q redox processes. The estimated errors were in the range of 0.03 to 0.06 pH units from the analysis of varience. 相似文献
8.
Mingming Liu Jiangyan Pi Xiaojie Wang Rong Huang Yamei Du Xiaoyang Yu Wenfeng Tan Fan Liu Kenneth J. Shea 《Analytica chimica acta》2016
A pH-responsive surface molecularly imprinted poly(ionic liquids) (MIPILs) was prepared on the surface of multiwall carbon nanotubes (MWCNTs) by a sol-gel technique. The material was synthesized using a 3-aminopropyl triethoxysilane modified multiwall carbon nanotube (MWCNT-APTES) as the substrate, bovine serum albumin (BSA) as the template molecule, an alkoxy-functionalized IL 1-(3-trimethoxysilyl propyl)-3-methyl imidazolium chloride ([TMSPMIM]Cl) as both the functional monomer and the sol-gel catalyst, and tetraethoxysilane (TEOS) as the crosslinking agent. The molecular interaction between BSA and [TMSPMIM]Cl was quantitatively evaluated by UV–vis spectroscopy prior to polymerization so as to identify an optimal template/monomer ratio and the most suitable pH value for the preparation of the MWCNTs@BSA-MIPILs. This strategy was found to be effective to overcome the problems of trial-and-error protocol in molecular imprinting. The optimum synthesis conditions were as follows: template/monomer ratio 7:20, crosslinking agent content 2.0–2.5 mL, temperature 4 °C and pH 8.9 Tris–HCl buffer. The influence of incubation pH on adsorption was also studied. The result showed that the imprinting effect and selectivity improved significantly with increasing incubation pH from 7.7 to 9.9. This is mainly because the non-specific binding from electrostatic and hydrogen bonding interactions decreased greatly with the increase of pH value, which made the specific binding affinity from shape selectivity strengthened instead. The polymers synthesized under the optimal conditions were then characterized by BET surface area measurement, FTIR, thermogravimetric analysis (TGA) and scanning electron microscopy (SEM). The adsorption capacity, imprinting effect, selective recognition and reusability were also evaluated. The as-prepared MWCNTs@BSA-MIPILs were also found to have a number of advantages including high surface area (134.2 m2 g−1), high adsorption capacity (55.52 mg g−1), excellent imprinting effect (imprinting factor of up to 5.84), strong selectivity (selectivity factor of 2.61 and 5.63 for human serum albumin and bovine hemoglobin, respectively), and good reusability. 相似文献
9.
An ultrasensitive polyclonal antiserum against ciprofloxacin (CPFX) was developed by introducing cationized bovine serum albumin (BSA) as the carrier. Conjugates used as immunogens were synthesized using CPFX coupled to BSA cationized with ethylenediamine and hexamethylenediamine, namely CPFX-eBSA and CPFX-hBSA. The results showed that the antisera immunized with CPFX-hBSA exhibit an improved sensitivity and specificity compared with those immunized with CPFX-eBSA. Under the conditions of optimal heterologous enzyme-linked immunosorbent assay, the optimal antiserum yielded an IC50 of 0.097 ng mL?1, which proves it to be more sensitive than any CPFX antibody. Cross-reactivities with norfloxacin, enrofloxacin, and ofloxacin were < 3.0 %. No cross-reactivities with penicillin and gentamicin were found. The limit of detection was 0.01 ng mL?1, which is far below the maximum residue level established by the EU regulation, suggesting the great potential of the presented antiserum for quantitative assays of CPFX in samples. 相似文献
10.
《液相色谱法及相关技术杂志》2012,35(17):3399-3414
Abstract Several ferrocenic compounds for derivatization of peptides and proteins were synthesized and then tested by reaction with bovine serum albumin (BSA). The reactivity of the reagents and the electroactivity of the derivatized BSA were estimated by the height of the ECD-signal after an HPLC analysis run. The most suitable reagent was 3-ferrocenylpropionic anhydride which reacts with BSA within 15 minutes at room temperature. The anhydride presented itself as a stable compound which can be synthesized in high yields. Up to pH 9–10 it is only slowly hydrolyzed, and its derivatization products are highly electroactive. Another reagent is especially suited to derivatize those proteins whose isoelectric points are higher than 10: Ferrocenylmethyl-succinimidyl-glycine-hydrochloride. This compound develops its derivatization activity only with pH values higher than 9, but it is rather difficult to prepare. 相似文献
11.
A one‐step method was developed for preparing Ag2S quantum dots (QDs) using a common protein [bovine serum albumin (BSA)] to entrap QDs precursors (BSA–Ag+). Fluorescence (FL) and ultraviolet spectra showed that the molar ratio of Ag+/BSA, temperature, and pH are the crucial factors for the quality of QDs. The QDs absorption wavelength and emission wavelength were about 340 and 450 nm. The average QDs particle size was estimated to be less than 5 nm, determined by transmission electron microscopy. The X‐ray power diffraction and XPS results showed that the synthesized product was indeed monoclinic Ag2S. With Fourier transform infrared spectra and thermogravimetry analysis, there might be conjugated bonds between Ag2S QDs and –OH, –NH, and –SH groups in BSA. In addition, FL spectra suggest that the designed QDs can produce static quenching with BSA and the Stern–Volmer quenching constant (Ksv) was calculated as 2.145 × 104. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
12.
Influence of pH of the BSA solutions on velocity of the rising bubbles, stability of foams, and properties of single foam and wetting films was studied. It was found that the solution pH affected significantly the BSA surface activity and properties of the protein adsorption layer under dynamic and static conditions. At pH close to the isoelectric point (pHIEP=4.8) the BSA showed the highest surface activity. The equilibrium microscopic foam films of thicknesses of 64–80 nm, depending on the BSA concentration, were obtained at pH=5.8. Under dynamic conditions the bubble rising velocity was reduced in a highest degree and the foam formed were most stable at the solutions pH-5.8 and 4.8. Lowering the bubble velocity shows that the BSA adsorption layer was formed, which retarded fluidity of the bubble surface. When the solution pH was significantly lower (pH=3.9) or much higher (pH=10) than the pHIEP then the BSA practically had no influence on the bubble velocity and the foam stability was drastically reduced. Moreover, the pH variations affected also the time of the three-phase contact (TPC) formation on mica surface covered by the BSA adsorption layers. These pH dependent changes in the BSA surface activity indicate that the BSA linear conformers, existing at pH far away from the pHIEP, have much higher affinity to aqueous phase resulting from higher net electrical charge present over the extended BSA molecule conformers. 相似文献
13.
Dr. Palraj Kalimuthu Prof. Lena J. Daumann Dr. Arjan Pol Prof. Huub J. M. Op den Camp Prof. Paul V. Bernhardt 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(37):8760-8768
We report the first electrochemical study of a lanthanoid-dependent methanol dehydrogenase (Eu-MDH) from the acidophilic verrucomicrobial methanotroph Methylacidiphilum fumariolicum SolV with its own physiological cytochrome cGJ electron acceptor. Eu-MDH harbours a redox active 2,7,9-tricarboxypyrroloquinoline quinone (PQQ) cofactor which is non-covalently bound but coordinates trivalent lanthanoid elements including Eu3+. Eu-MDH and the cytochrome were co-adsorbed with the biopolymer chitosan and cast onto a mercaptoundecanol (MU) monolayer modified Au working electrode. Cyclic voltammetry of cytochrome cGJ reveals a well-defined quasi-reversible FeIII/II redox couple at +255 mV vs. NHE at pH 7.5 and this response is pH independent. The reversible one-electron response of the cytochrome cGJ transforms into a sigmoidal catalytic wave in the presence of Eu-MDH and its substrates (methanol or formaldehyde). The catalytic current was pH-dependent and pH 7.3 was found to be optimal. Kinetic parameters (pH dependence, activation energy) obtained by electrochemistry show the same trends as those obtained from an artificial phenazine ethosulfate/dichlorophenol indophenol assay. 相似文献
14.
15.
Seyed Jamal Tabatabaei Rezaei Khadijeh Norouzi Ali Hesami Asemeh Mashhadi Malekzadeh Ali Ramazani Vahid Amani Roya Ahmadi 《应用有机金属化学》2018,32(4)
A novel pH‐responsive magnetic nanogels were developed with the aim of targeted delivering and simultaneously releasing of newly synthesized Au(III)‐based anticancer drug, Au(1,7‐Phen)Br3. The obtained nanogels were characterized by FT‐IR, DLS, EDAX, TEM, XRD, ICP‐Ms and MRI. The TEM images showed that the nanogels had a spherical shape with a mean diameter of 20 nm. The in vitro release studies of Au (III)‐loaded nanogels showed a pH‐triggered controlled release of drugs. The in vitro cytotoxicity assay of samples to human cervical cancer HeLa cell lines indicated that the Au(III)‐loaded magnetic nanogels exert higher cytotoxicity in comparison with free Au(III) complex. Fluorescent microscope images indicated that these magnetic nanogels possessed notable cell specific targeting in vitro in the presence of an external magnetic field. The results show that this superparamagnetic nanocarrier is a promising candidate for inhibiting growth of tumor cells. 相似文献
16.
Minling Ding Qi Shu Nan Zhang Chaoren Yan Huizhe Niu Xiaoqian Li Ping Guan Xiaoling Hu 《Electroanalysis》2022,34(2):263-274
The amyloid-β peptide (1–42) (Aβ42) can provide high diagnostic accuracy for the early diagnosis of Alzheimer's disease (AD). In this study, an immunosensor based on the peroxidase-like activity of heme-Aβ42 was designed for Aβ42 detection. The glassy carbon electrode (GCE) was electrodeposited Au particles (GCE/Au). The GCE/Au was modified using polythionine-methylene blue (PTH−MB), AuNPs, monoclonal antibody (anti-Aβ42), and bovine serum albumin (BSA), successively. The GCE/Au/PTH−MB/AuNPs/anti-Aβ42/BSA could competitively recognize Aβ42 and heme-Aβ42. The anchored heme-Aβ42 showed strong electrocatalytic activity between H2O2 and ferrocenemethanol. Under optimum conditions, we determined detection limits of 17.3 pM in PBS pH 7, 25.2 pM in serum, and 23.8 pM in saliva. The recovery ranged from 71.0 % to 117.8 %. 相似文献
17.
Lingzhi Feng Bohong Kan Kongyin Zhao Junfu Wei Dunwan Zhu Linhua Zhang 《Journal of Sol-Gel Science and Technology》2014,71(3):428-436
Calcium silicate particles containing mesoporous SiO2 on the surface (CaSiO3@SiO2) were prepared by acid modification of calcium silicate with diluted hydrochloric acid. Bovine serum albumin (BSA) molecularly imprinted polysiloxane (MIP) was synthesized using silane as the functional monomer, BSA as the template and CaSiO3@SiO2 particles as the matrix in an aqueous phase. SEM, granulometry, FT-IR and BET analysis were used to characterize the protein MIP. Influence factors on the rebinding capacity of the MIP were investigated, such as the pH in treating CaSiO3, eluent type and silane proportion. The mass of BSA loading and rebinding on CaSiO3@SiO2 and MIP was investigated. The adsorption and recognition properties of the MIP were evaluated and the results showed that the MIP exhibited an obvious improvement in terms of rebinding capacity for BSA as compared with non-imprinted polysiloxane (NIP). BSA imprinted polysiloxane could recognize the template protein by using Lys, Ova, Hb, and Glo as control proteins, and the selectivity factor (β) was above 2.3. The rebinding capacity of BSA imprinted polysiloxane for BSA reached 81.31 mg/g, which was 2.25 times of NIP. 相似文献
18.
Cinthia Meirelly de Araújo Elpídio Carlos Eduardo de Araújo Padilha Francisco Canindé de Sousa Júnior Ruthinéia Jéssica Alves do Nascimento Camilla Milena de Araújo Elpídio Sérgio Dantas de Oliveira Júnior Gorete Ribeiro de Macedo Everaldo Silvino dos Santos 《Chromatographia》2018,81(10):1355-1364
This study deals with the fabrication and characterization of a pellicular adsorbent appropriate for the expanded bed adsorption (EBA) process. The synthesized adsorbent has an yttria-stabilized zirconia nucleus coated with agarose. Morphological analysis of the coated particles was performed by light-scattering microscopy and showed an average diameter of 197.54 and 202.25 µm, for the nucleus and coated particle, respectively. A screening for the reactive dyes reactive blue 19 (RB19), reactive blue 21 (RB21) and reactive orange 107 (RO107) was performed after immobilization onto the pellicular adsorbent by changing the pH, aiming at finding the binding capacity of these to adsorb bovine serum albumin (BSA). The reactive orange 107 was selected and it was more stable at pH 4.5. Study of the kinetics between BSA and the dye-immobilized particle showed that equilibrium is reached before 1 h. The adsorption isotherm of BSA onto RO107-immobilized adsorbent fitted the Langmuir model showing a qm = 102.328 mg BSA/mL of adsorbent. The pellicular adsorbent also showed good expansion even at a high operating flow rate. Therefore, at a linear velocity as high as 2725 cm/h, a dynamic capacity of 15.7 mg of BSA/mL of adsorbent was obtained. 相似文献
19.
Al Electrode Modified by Au Atoms as a Novel Electrode for Electrocatalytic Oxidation of Thiosulfate
An aluminum electrode modified with gold atoms was introduced as a novel electrode. Gold atoms were deposited both chemically and electrochemically onto the aluminum electrode to make an aluminum/gold (Al/Au) modified electrode (ME). The experimental results showed that the Al/Au modified electrode prepared by chemical deposition, exhibits much more current than the electrochemical deposition method. The electrochemical behavior of the Al/Au modified electrode was studied by cyclic voltammometry. This modified electrode showed two pairs of peaks, a1c1 and a2c2, with surface‐confined characteristics in a 0.5 M phosphate buffer. The dependence of Epa of the second peak (a2c2) on pH shows a Nernestian behavior with a slope of 55 mV per unit pH. The effect of different supporting electrolytes, solution's pH and different scan rates on electrochemical behavior of Al/Au modified electrode was studied. Au deposited electrochemically on a Pt electrode (Pt/Au) was also used as another modified electrode. A comparative study of electrochemical behavior of bare Al, Pt/Au and Al/Au modified electrodes showed that both Pt/Au and Al/Au electrodes have the ability of electrocatalytic oxidation of S2O32?, but the electrocatalytic oxidation on the latter was better than the former. The kinetics of the catalytic reaction was investigated by using cyclic voltammetry and chronoamperometry techniques. The average value of the rate constant for the catalytic reaction and the diffusion coefficient were evaluated by means of chronoamperometry technique. 相似文献
20.
采用氧化还原法制备了α, δ, γ-MnO2载体, 采用原位还原法制备了Au负载量为0.5%-3.0%的Au/γ-MnO2催化剂, 并采用X射线衍射、扫描电镜、透射电镜和N2物理吸附等手段对其进行了表征. 透射电镜照片表明Au/γ-MnO2催化剂中Au颗粒的大小约为10 nm. 采用无溶剂存在下的甲苯氧化反应测试所制备样品的催化活性. 结果表明, 甲苯转化率随着Au负载量的增加而增大. 这是由于Au颗粒数量增多, 尺寸减小的缘故. 同时, 负载Au颗粒对苯甲醛具有较高的选择性. Au/γ-MnO2催化剂具有良好的重复使用性. 相似文献