茶碱-铜(Ⅱ)离子配位分子印迹膜的制备及表征

以茶碱为模板分子,铜离子为配体、4-乙烯吡啶(4-VP)为功能单体、乙二醇二甲基丙烯酸酯(EDMA)为交联剂,在聚偏氟乙烯(PVDF)基膜上采用表面涂覆热聚合的方法制备了金属配位分子印迹膜,通过平衡结合实验研究了印迹膜对茶碱的结合性能和结合选择性。结果表明,铜离子的配位作用能提高印迹膜的结合性,在茶碱浓度为0.2 mmol/L时结合量从1.61μmol/g提高到了2.69μmol/g。在铜离子配位的作用下印迹膜对茶碱的结合能力高于同样化学组成的非印迹膜。相比于可可碱印迹膜对茶碱有较好的选择性,在浓度为0.05 mmol/L时选择性达到了2.39。     

CuMOF基催化剂的制备及其电催化性能研究

以五水硝酸铜,对苯二甲酸,2-氨基嘧啶,科琴黑为原材料,通过水热法及惰性气氛下煅烧过程得到产物CuMOF-x(x=1,2,3)。重点研究了单配体对苯二甲酸、2-氨基嘧啶、二元混合配体对产物的氧还原催化性能的影响。利用电化学工作站,采用线性扫描伏安法对其氧还原催化性能进行测试,并采用Koutecky-Levich方程对其氧还原电子转移数进行计算。研究结果表明,含氮单配体2-氨基嘧啶对产物氧还原催化性能的影响要优于羧酸单配体对苯二甲酸配体,而两者的二元混合配体效果最佳;所制得的3种催化剂CuMOF-x(x=1,2,3)催化氧气还原均以4e^-途径进行。     

三价铬镀液中配体的作用

三价铬镀铬液中的配体对镀液的稳定性和沉积速度影响极大,从三价铬镀液的化学和电化学特性分析入手,介绍了镀液中所加配体(如羧酸、羟基羧酸、氨基羧酸及其盐)的作用:(1)与三价铬离子形成活性配位离子加快电沉积速度;(2)抑制Cr3 的羟桥化反应;(3)可以掩蔽杂质金属离子,减少杂质金属离子对镀层质量的干扰,使电镀能持续进行;(4)可以稳定镀液.特别指出,只有选用能形成活性配位离子的配体,使电镀能持续进行,才能获得性能良好的厚铬镀层.     

羽毛蛋白接枝丙烯酸-丙烯酰胺高吸水性树脂的吸附性能

通过水溶液聚合法合成了羽毛蛋白接枝丙烯酸-丙烯酰胺高吸水树脂,即FP-P(AA-AM)。研究了树脂在单一Cd2+溶液中的吸附行为以及在Cd2+、Cu2+、Zn2+三元混合溶液中的选择性吸附性能。结果表明,在单一Cd2+溶液中,FP-P(AA-AM)树脂对Cd2+的吸附容量随硫酸镉溶液浓度的增大而增大,最高可达2.4mmol/g。吸附Cd2+至饱和的树脂能在1mol/L的HCl溶液中很好的进行解吸附,3min时解吸附率即可达到83.3%。在较高浓度的三元金属离子混合溶液中,FP-P(AA-AM)树脂对3种离子呈现出一定的选择性吸附,其平衡吸附量顺序为:Cu2+Cd2+Zn2+。     

三唑配体化合物的电子结构和磁性质的第一性原理研究

利用第一性原理方法研究了化合物[CuⅡ CuⅠ (trz)cl2](trz=triazole)的电子结构和磁性质,计算了化合物的磁矩和态密度.结果显示,自旋磁矩主要来源于Cu离子,而Cl、N1、N2和C原予也有较小的自旋磁矩分布.化合物中Cu离子与三唑配体和μ3配体之间存在铁磁耦合.铁磁性质来源于自旋退局域化效应.Cul(即CuⅡ)离子与三唑配体之间的铁磁相互作用比Cu2(即CuⅠ)离子与三唑配体之间的铁磁相互作用强.     

Ni-Fe普鲁士蓝的离子交换选择性研究

研究了Ni-Fe普鲁士蓝对不同价态金属离子的交换选择性。在Ni-Fe普鲁士蓝与一价Cs+溶液反应中,Ni-Fe普鲁士蓝主要由K+与Cs+进行离子交换;而在与二价和三价的离子溶液反应中,离子交换主要是通过目标离子(Cr3+、Sr2+、Cu2+)与K+和Ni 2+发生交换。结合全谱等离子直接光谱(ICP)和穆斯堡尔谱分析得出,在以上4种离子存在的情况下,Ni-Fe普鲁士蓝对Cs+具有最高的离子选择性,Ni-Fe普鲁士蓝对这4种离子选择性顺序为Cs+Sr2+Cr3+Cu2+。     

Fe_3O_4-羧甲基纤维素-聚乙烯亚胺微球的制备及对Cd~(2+)的吸附性能

利用静电自组装的方法,将羧甲基纤维素(CMC)组装到Fe3O4上得到Fe3O4-羧甲基纤维素(Fe3O4-CMC),再用戊二醛将聚乙烯亚胺(PEI)交联到Fe3O4-CMC上,制备出Fe3O4-羧甲基纤维素-聚乙烯亚胺(Fe3O4-CMC-PEI)微球。用透射电镜、X射线衍射、红外光谱、X射线光电子能谱和震动样品磁强计对Fe3O4-CMC-PEI微球进行了表征,用原子吸收分光光度计测定了其对Cd2+离子的吸附性能。结果表明,CMC组装到Fe3O4表面,Fe3O4-CMC和PEI在戊二醛的作用下发生交联得到Fe3O4-CMC-PEI微球。Fe3O4-CMC-PEI微球的粒径为10~30nm,饱和磁化强度为55.20A·m2/kg。Fe3O4在微球中的结构没有发生改变,仍为纯单一相的反尖晶石型结构。Fe3O4-CMC-PEI微球对Cd2+离子表现出了良好的吸附性能,饱和吸附容量为69.44mg/g,吸附等温数据符合Langmuir模型,吸附动力学符合拟二级反应动力学模型。     

锡硫化合物包覆的水溶性硒化镉量子点的制备与表征

以Na2S、Na2SnO3、稀盐酸及水合肼为原料成功合成了锡硫化合物(Metalchal cogenidometalates,MCCs)。该化合物在离子溶液中解离出SnS44-或Sn2S46-,这两种低聚阴离子因其电子空间结构特殊而具有配位作用,故能置换CdSe量子点表面原有的长链有机配体,从而实现量子点从有机相到无机相的转移。配体交换后的量子点可以较好地分散在水、氨水、水合肼和二甲亚砜等一系列极性溶剂中。我们分别用透射电子显微镜(TEM)、紫外吸收光谱(UV)、荧光发射光谱(PL)和红外吸收光谱(FTIR)表征了CdSe的分散性、光学性质及表面配体情况。     

聚(丙烯酰胺-共聚-苯并-18-冠-6丙烯酰胺)凝胶光栅构建及冠醚含量对铅离子检测性能的影响

通过微接触复刻技术制备了具有优良Pb²⁺检测性能的聚(丙烯酰胺-共聚-苯并-18-冠-6丙烯酰胺)(PAB)凝胶光栅。该凝胶光栅的高度可随着溶液中Pb²⁺浓度的变化而变化。通过优化PAB凝胶光栅中的冠醚含量发现，当冠醚含量为20%(摩尔分数)时，凝胶光栅可展现出最佳的Pb²⁺检测性能。该PAB凝胶光栅可实现对水体中Pb²⁺的高灵敏、快速、高选择性和重复性检测，其检测限可低至10^-9mol/L,响应时间仅为4min。因此，该凝胶光栅系统在灵敏快速地检测水体中Pb²⁺方面具有重要的应用前景。     

1-氨基-3-十二烷基-1，2，3-三唑硝酸盐的合成研究

以乙二醛、水合肼及溴代十二烷为原料,经加成-消除、环化、烷基化、复分解4步反应得到1-氨基-3-十二烷基-1,2,3-三唑硝酸盐。通过核磁、红外、质谱等分析手段对目标产物进行了结构表征。探索并优化了加成-消除、环化和烷基化反应条件。各步反应的最佳条件为：加成-消除反应中,n（水合肼）n（乙二醛）n（甲醇）＝319,70℃反应5 h,收率为90．3％;环化反应中,m（二氧化锰）m（乙二腙）＝21,20℃反应3h,收率为88．2％;烷基化反应中,n（1-氨基-1,2,3-三唑）n（溴代十二烷）＝11．5,80℃反应40h,收率为64．5％;复分解反应易进行且得率高,反应3．5h,产率为80．4％,目标产物总收率为41．3％。     

Fabrication, characterization, and enzymatic activity of fungal protease--nanogold membrane bioconjugate

This study describes the synthesis of a free-standing nanogold membrane by the spontaneous reduction of aqueous chloroaurate ions by the diamine molecule DAEE at a liquid-liquid interface. The free standing nanogold membrane, provides a biocompatible surface for the immobilization of proteins. F-Protease (F-Prot) was then bound to the nanogold membrane via interaction with the gold nanoparticles leading to a new class of biocatalyst. A highlight of the new biocatalyst wherein the enzyme is bound to the nanogold membrane is the ease with which separation from the reaction medium may be achieved by simple filtration. In relation to the free enzyme in solution, the F-Prot in the bioconjugate material exhibited a slightly higher biocatalytic activity and significantly enhanced pH and temperature stability. The F-Prot nanogold membrane bioconjugate material also exhibited excellent biocatalytic activity over ten successive reuse cycles.     

Surface enhanced Raman scattering spot tests: a new insight on Feigl's analysis using gold nanoparticles

Traditional Feigl's spot tests can be greatly improved with the aid of gold nanoparticles and Raman probes, by monitoring the changes in the surface enhanced Raman scattering (SERS) of the analytes directly applied on a filter paper previously impregnated with the selective organic reagent. As a proof of concept, diphenylthiocarbazone (dithizone) was treated with citrate stabilized gold nanoparticles and employed in paper spot tests for a variety of transition and heavy metal ions. Below 10(-5) mol L(-1), only mercury(II) ions were able to displace the dithizone molecules from the "coordination shell" of the gold nanoparticles, leading to a systematic decay of the Raman signals. Because of the huge enhancement of the dithizone vibrational peaks, the SERS spot tests allowed the detection of picograms of Hg(2+) ions.     

Gold nanoparticles bound on microgel particles and their application as an enzyme support

Submicron-sized poly(N-isopropyl acrylamide)/polyethyleneimine core-shell microgels were prepared in aqueous media by using tert-butyl hydroperoxide (TBHP) as an initiator, and then the gold nanoparticles (～8?nm) were formed on the surface of the microgels. The amino groups on the polyethyleneimine (PEI) chains act as the binder for the assembly of the gold nanoparticles/microgel complex. In aqueous media the microgels are highly stable with the gold nanoparticles on their extended PEI chains, and this multi-scale nanoparticle complex can be recovered from water and redispersed in water. The nanogold/microgel particles were conjugated with the enzymes horseradish peroxidase (HRP) and urease. It is found that under identical assay conditions the enzyme/nanogold/microgel systems exhibit enhanced biocatalytic activity over free enzymes in solution, especially at lower enzyme concentrations. In addition, compared to free HRP, the HRP/nanogold/microgel systems show higher activity at varied pHs and temperatures, as well as higher storage stability. Thus the novel nanogold/microgel particles can serve as an excellent support for enzymes.     

One-pot synthesis and strong near-infrared upconversion luminescence of poly(acrylic acid)-functionalized YF<Subscript>3</Subscript>:Yb<Superscript>3+</Superscript>/Er<Superscript>3+</Superscript> nanocrystals

This paper describes the synthesis of new upconverting luminescent nanoparticles that consist of YF₃:Yb³⁺/Er³⁺ functionalized with poly(acrylic acid) (PAA). Unlike the upconverting nanocrystals previously reported in the literature that emit visible (blue-green-red) upconversion fluorescence, these as-prepared nanoparticles emit strong near-infrared (NIR, 831 nm) upconversion luminescence under 980 nm excitation. Scanning electron microscopy, transmission electron microscopy, and powder X-ray diffraction were used to characterize the size and composition of the luminescent nanocrystals. Their average diameter was about 50 nm. The presence of the PAA coating was confirmed by infrared spectroscopy. The particles are highly dispersible in aqueous solution due to the presence of carboxylate groups in the PAA coating. By carrying out the synthesis in the absence of PAA, YF₃:Yb³⁺/Er³⁺ nanorice materials were obtained. These nanorice particles are larger (∼700 nm in length) than the PAA-functionalized nanoparticles and show strong typical visible red (668 nm), rather than NIR (831 nm), upconversion fluorescence. The new PAA-coated luminescent nanoparticles have the pottential be used in a variety of bioanalytical and medical assays involving luminescence detection and fluorescence imaging, especially in vivo fluorescence imaging, due to the deep penetration of NIR radiation.      

Cytotoxicity of spherical gold nanoparticles synthesised using aqueous extracts of aerial roots of Rhaphidophora aurea (Linden ex Andre) intertwined over Lawsonia inermis and Areca catechu on MCF‐7 cell line

A facile synthesis of gold nanoparticles (GNPs) using the aqueous extracts of the aerial roots of Rhaphidophora aurea (Linden ex Andre) intertwined over Lawsonia inermis and Areca catechu was carried out under different conditions, namely room temperature, higher temperature, sonication, solar irradiation and pH variation. The surface plasmon resonance (SPR) band at 536 and 575 nm obtained in UV–visible spectrum revealed the formation of AuNP''s. The sharp SPR band of the synthesised nanogold indicates the formation of spherical‐shaped and uniform‐sized nanoparticles. The TEM analysis revealed spherical nanogold particles of size 35 and 10 nm for MM and MP extracts. The secondary metabolites present in the aqueous extract are suggested to be responsible for the reduction of metal ions to metal nanoparticles as evidenced from results of FTIR analysis. Rapid synthesis of GNPs by sunlight is the production of microscopic grains of gold due to the dissociation of gold chloride. This may induce the reaction between secondary metabolites and gold chloride solutions and results in GNPs. The cytotoxic activity of the synthesised nanogold studied against human breast cancer cells (MCF‐7) by 3‐[4,5‐dimethylthiazol‐2‐yl]2,5‐diphenyltetrazolium bromide assay showed significant activity at higher concentration.Inspec keywords: toxicology, gold, nanoparticles, nanomedicine, nanofabrication, cellular biophysics, particle size, surface plasmon resonance, ultraviolet spectra, visible spectra, transmission electron microscopy, dissociation, cancer, biological organs, Fourier transform infrared spectraOther keywords: cytotoxicity, spherical gold nanoparticles, aerial roots, Rhaphidophora aurea, Linden ex Andre, Lawsonia inermis, Areca catechu, MCF‐7 cell line, sonication, solar irradiation, pH variation, surface plasmon resonance, UV–visible spectrum, spherical‐shaped nanoparticles, uniform‐sized nanoparticles, TEM analysis, spherical nanogold particles, secondary metabolites, metal ions, FTIR analysis, microscopic grains, dissociation, gold chloride solutions, cytotoxic activity, human breast cancer cells, 3‐[4,5‐dimethylthiazol‐2‐ yl]2,5‐diphenyltetrazolium bromide assay, wavelength 536 nm, wavelength 575 nm, Au     

Fast colorimetric detection of copper ions using L-cysteine functionalized gold nanoparticles

This communication reports an efficient visual detection method of Cu2+ by L-cysteine functionalized gold nanoparticles in aqueous solution. Upon exposure to Cu2+, the gold nanoparticle solution changed from red to blue, in response to surface plasmon absorption of dispersed and aggregated nanoparticles. This colorimetric sensor allows a rapid quantitative assay of Cu2+ down to the concentration range of 10(-5) M. Recognition of Cu2+ and formation of the aggregates are proposed to occur via a 2 : 1 sandwich complex between L-cysteine and Cu2+.     

One pot synthesis of monodispersed L-glutathione stabilized gold nanoparticles for the detection of Pb2+ ions

Direct mixture of Au³⁺ with glutathione (GSH), which act as both reduction agents and stabilizers, in aqueous solution gave rise to production of gold nanoparticles (Au NPs) with uniform sizes of around 21 nm. The GSH stabilizer Au NPs in solution show immediate aggregation after addition of 1 mol/L NaCl aqueous solution containing Pb²⁺ ions. The Pb²⁺-induced aggregation in Au NP solution is monitored by both colorimetric response and UV-vis spectroscopy. A rather broad linear range (from 0.1 to 30 μmol/L) and low detection limit (0.1 μmol/L) are explored for Au NP sensors used for detection of Pb²⁺ ions. Furthermore, the response of GSH-stabilized Au NPs toward Pb²⁺ ions is specific compared with other possible interferants (Hg²⁺, Mg²⁺, Zn²⁺, Ni²⁺, Cu²⁺, Co²⁺, Ca²⁺, Mn²⁺, Cd²⁺, and Ba²⁺).     

纳米Au在蒙脱石层间的插层组装

以Na基蒙脱石为载体,分别以十二胺和PAA作为插层剂,利用此类插层剂可以捕捉金胶体的特点,使预先制备的金胶体插层于蒙脱石的层间制备组装型纳米金催化剂,并考察了高温焙烧对插层效果的影响。此外,以Au(en2)Cl3作为金的前驱体,研究了利用蒙脱石的阳离子交换特性直接进行纳米金插层组装的可行性。采用X射线衍射(XRD)、荧光分析(XRF)和透射电子显微镜(TEM)对所制备的样品进行了表征,结果表明:基于阳离子交换插层的制备方法未能实现纳米金的插层组装,金颗粒主要负载于蒙脱石片层的外表面,而基于配位俘获机理的插层组装方法所制备的纳米金在蒙脱石层间的插层组装效果良好,高温焙烧虽然导致层间纳米金的迁移,但金的粒径仍然保持在较低的尺寸范围。     

Surface modification of YAG:Ce3+ nanoparticles by poly(acrylic acid) and their biological application

Yttrium aluminum garnet Y₃Al₅O₁₂ (YAG):Ce³⁺ nanoparticles prepared by glycothermal method are modified with poly(acrylic acid) (PAA). This surface modification enables YAG:Ce³⁺ nanoparticles to be well dispersed in phosphate-buffered saline (PBS) without any serious aggregation. YAG:Ce³⁺ nanoparticles emit yellowish green light under the excitation of blue light. This fluorescent property does not change after the modification of PAA. Streptavidin (SA) is immobilized on the surface of PAA-modified YAG:Ce³⁺ nanoparticles by using carboxyl groups of PAA as cross-linking sites. We demonstrate the quantitative analysis of bovine serum albumin in PBS by SA-immobilized YAG:Ce³⁺ nanoparticles.     

Au-modified silicon nanowires for surface-enhanced fluorescence of Ln3+ (Ln = Pr, Nd, Ho, and Er)

The interaction of the surface plasmons of gold nanoparticles on silicon nanowires with fluorophores, lanthanide ions (praseodymium ions, Pr³⁺, neodymium ions Nd³⁺, holmium ions Ho³⁺, and erbium ions Er³⁺) was investigated. In the presence of Au/Si nanomaterials, the fluorescence peaks were significantly enhanced, which resulted in about 2 orders of magnitude enhancement. The photoluminescence studies revealed that the enhanced fluorescence originates from the local field enhancement around Ln³⁺ ions, caused by the electronic plasmons resonance of the gold nanoparticles. Results showed that this Au/Si nanostructure had larger enhancement factor than that caused by unsupported Au nanoparticles. These results might be explained by the local field overlap originated from the closed and fixed gold nanoparticles on silicon nanowires.