4-巯基苯硼酸修饰二维二硫化钼纳米复合材料的制备及其用于N-糖肽特异性富集

蛋白质的N-糖基化修饰在多种生物过程中发挥着至关重要的作用，近年来的许多研究证实异常的蛋白质糖基化与多种疾病的发生发展密切相关，表明糖基化蛋白质具有较大的潜力成为新的生物标志物或者药物靶标。在样本的处理过程中，对N-糖基化肽段进行富集分离后再进行质谱分析已经成为糖蛋白质组学分析前的必要步骤。但是，由于复杂生物样本中N-糖基化肽段的丰度低和离子化效率差等问题，通过质谱鉴定N-糖肽仍然是一项艰巨的任务。研究通过将纳米金线（Au）、4-巯基苯硼酸（4-MPB）与超薄二维二硫化钼（2D-MoS₂）进行反应，成功制备了一种用于富集蛋白质N-糖基化肽段的新型功能纳米复合材料（MoS₂/Au/4-MPB）。二硫化钼纳米材料的层状结构可以为反应提供大量的可修饰位点，便于修饰纳米金线；功能基团4-巯基苯基硼酸对N-糖肽具有高度的选择性，可以对生物样品中N-糖基化肽段进行特异性富集。使用标准蛋白人免疫球蛋白G（IgG）和牛血清白蛋白（BSA）胰蛋白酶酶切产物对新型功能纳米材料的N-糖基化肽段的富集性能进行评估，其灵敏度达到5 fmol，选择性达到1：1000。将其用于生物样品中N-糖基化肽段的富集，从50 μg尿液外泌体蛋白胰蛋白酶酶切产物中共富集鉴定出768个N-糖肽，归属于377个蛋白质。这些结果表明该新型功能纳米复合材料对复杂生物样品中N-糖肽的选择富集有着巨大的应用潜力，为糖蛋白质组的研究提供了一种新方法。     

不同晶型二氧化锰纳米棒催化氧化氯苯性能的研究

采用水热法分别合成了α-, β-, γ-MnO₂纳米棒, 使用X射线衍射(XRD)、扫描电镜(SEM)、透射电镜(TEM)、氢气程序升温还原(H₂-TPR)和X射线光电子能谱(XPS)等技术对三种晶型MnO₂纳米棒的结构和形貌进行了表征, 并以氯苯(CB)为探针考察了其催化活性和稳定性. 结果表明, 三种晶型MnO₂纳米棒在低温范围内均有较高的催化活性, 且活性顺序为α-MnO₂＞γ-MnO₂＞β-MnO₂. 此外, 还发现三种晶型MnO₂纳米棒比无定形MnO₂有更强的抗氯中毒能力. 在三种晶型MnO₂纳米棒中, α-MnO₂纳米棒催化氧化氯苯的活性最佳, 主要是由于该种MnO₂纳米棒含有丰富的晶格氧并且具有较强的可还原能力.     

纳米α-Fe2O3/(IPDI-HTPB)复合粒子的制备及其催化性能研究

为改善纳米α-Fe₂O₃在复合推进剂中的分散性，提高其催化性能，选择推进剂的配方组分固化剂异氟尔酮二异氰酸酯（IPDI）为嫁接桥梁，将端羟基聚丁二烯（HTPB）接枝在纳米α-Fe₂O₃粒子的表面，制得纳米α-Fe₂O₃/（IPDI-HTPB）复合粒子.首先研究了IPDI与HTPB反应动力学，优化制备条件；然后采用X射线衍射仪（XRD）、透射电子显微镜（TEM）、傅里叶变换红外光谱仪（FTIR）和热重分析（TGA）等手段对复合粒子的结构进行表征，采用DTA对比了复合前后纳米α-Fe₂O₃粒子对高氯酸铵（AP）热分解的催化性能的影响.结果表明，依靠IPDI的偶联作用，可将HTPB接枝在纳米α-Fe₂O₃的表面，包覆层厚度约为5 nm，改性后的纳米α-Fe₂O₃/（IPDI-HTPB）复合粒子的分散性大幅提高，纳米α-Fe₂O₃/（IPDI-HTPB）复合粒子对AP的热分解的催化性能也明显优于纯纳米α-Fe₂O₃粒子.     

三联吡啶化合物的溶剂致荧光变色及丁醇异构体鉴别

在三联吡啶分子中引入N,N-二甲基官能团, 实现了三联吡啶分子的局部激发态发光. 研究发现, 溶剂的极性诱导三联吡啶的偶极矩发生变化, 实现了从深蓝光(λ_max=384 nm)到黄光(λ_max=558 nm)的溶剂致荧光变色. 由于三联吡啶的荧光易受醇溶剂中—OH基团振荡猝灭, 不同空间位阻的正丁醇、 异丁醇、 仲丁醇及叔丁醇溶剂使得三联吡啶发光光色相近, 但发光强度的差异较大. 三联吡啶进一步与ZnCl₂配位得到了三联吡啶-Zn(Ⅱ)配合物, 金属离子Zn(Ⅱ)的配位作用促进了三联吡啶分子内电荷转移. 由于电子给体N,N-二甲基官能团可发生平面扭曲, 丁醇异构体可调节三联吡啶-Zn(Ⅱ)的局部激发态和扭曲分子内电荷转移发光, 进而实现其在丁醇异构体溶剂中发光光色的调节. 因此, 三联吡啶和三联吡啶-Zn(Ⅱ)具有良好的溶剂致荧光变色性能, 可应用于4种丁醇异构体的鉴别.     

一种新型温度响应性聚氨基酸/聚类肽嵌段共聚物的合成与表征

以正己胺为引发剂, 通过γ-炔丙基-L-谷氨酸羧酸酐(PLG-NCA)和N-正辛基甘氨酸羧酸酐(Oct-NNCA)逐步开环聚合和后修饰策略合成了分子量分布较窄的温度响应性两嵌段共聚物寡聚乙二醇单元修饰的聚(γ-炔丙基-L-谷氨酸)-b-聚(N-正辛基甘氨酸)[(PPLG-g-EG₃)-b-PNOG]. 通过示差扫描量热法(DSC)研究了不同比例聚合物的结晶行为; 利用圆二色谱法(CD)研究了聚合物的二级结构, 并研究了聚合物在水溶液中的自组装行为, 采用透射电子显微镜(TEM)观察了组装后的形貌. 结果表明, 该温度响应性聚合物在室温下呈现α-螺旋结构, 随着温度升高, α-螺旋的构象减少. 该聚合物可以在水溶液中自发组装成棒状结构.     

原位生长的α-Fe2O3/ZnO异质纳米棒阵列对乙醇气体的高选择性检测

采用两步溶液法在陶瓷管上原位生长了ZnO纳米棒阵列,然后以ZnO纳米棒为载体,通过水热法在其表面负载α-Fe₂O₃纳米粒子,生成异质α-Fe₂O₃/ZnO复合纳米材料。 α-Fe₂O₃/ZnO纳米棒直径30~80 nm,长1 μm左右,交叉排列形成纳米棒阵列,α-Fe₂O₃纳米粒子粒径约10 nm,均匀分布在ZnO纳米棒表面。 将纯ZnO和α-Fe₂O₃/ZnO纳米棒阵列制成气敏元件,测试并对比了2种气敏元件的气敏性能,揭示其气敏机理。 结果表明:α-Fe₂O₃纳米粒子的复合显著提高了ZnO纳米棒阵列对乙醇气体的灵敏度和选择性,在工作温度370 ℃时,对100 μL/L乙醇气体的响应值为85.4,是同条件下ZnO器件对乙醇响应值(9.4)的9.1倍,响应时间7 s,最低检出限为0.01 μL/L。 相关研究可以应用于痕量乙醇的快速、高灵敏度和高选择性检测。     

基于荧光偏振的高灵敏度蛋白激酶活性分析

利用TiO₂纳米棒与磷酸化肽的特异性相互作用,基于荧光偏振检测,建立了快速、简便的高灵敏度蛋白激酶活性分析方法. 在蛋白激酶催化作用下,荧光标记的肽底物被磷酸化,磷酸化的荧光肽通过磷酸基团特异性结合在TiO₂纳米棒表面,从而使底物肽上标记的荧光分子的旋转速率发生改变,通过对荧光偏振度进行测量,可实现蛋白激酶活性的定量检测,该方法对蛋白激酶A(PKA)的检出限可达0.0004 U·μL^-1. 此外,该方法还成功用于PKA抑制剂H-89的检测,在基于蛋白激酶抑制剂的靶向药物筛选方面具有很好的应用前景.     

金纳米粒子杂化超分子水凝胶的制备与性能

在制备水溶性硫辛酸酯封端的甲氧基聚乙二醇-聚己内酯嵌段共聚物(MPEG-PCL-ALA)单层包覆金纳米粒子的基础上, 在水溶液中, 利用α-环糊精(α-CD)与单层包覆金纳米粒子的包合作用构建杂化超分子水凝胶. 透射电子显微(TEM)照片显示, 金纳米粒子的尺寸为6～8 nm. X射线衍射测试表明, 所制备的水凝胶中含有α-环糊精与MPEG-PCL嵌段共聚物包合形成的多聚准轮烷的特征衍射峰(2θ＝19.7°). 紫外-可见吸收光谱显示, 单层包覆金纳米粒子的水溶液及其与α-CD包合形成的水凝胶在525 nm处均出现表面等离子共振吸收峰, 单层包覆金纳米粒子溶液存放3个月后, 其表面等离子共振吸收峰未发生明显红移, 表明单层包覆金纳米粒子的水溶液具有较好的稳定性.     

利用三中心氢键限制芳酰胺构象的核磁共振氢谱分析

设计并合成了9个可形成三中心氢键和6个可形成二中心氢键的N-芳基芳酰胺模型化合物, 基于它们在氯仿和二甲基亚砜(DMSO)中的一维核磁共振波谱, 系统地分析了羰基对βH和γH的去屏蔽效应. 将Δ(δ_βH)和Δ(δ_γH)的值结合在一起, 分析了三中心氢键对芳酰胺分子的构象限制效果, 发现N-(2-氟苯基)-2-氟苯甲酰胺、 N-(2-甲氧基苯基)-2-氟苯甲酰胺和N-(2-氟苯基)-2-甲氧基苯甲酰胺这3个N-芳基芳酰胺在酰胺基团的左右两侧都能展现出很好的构象控制效果, 因此认为这3种结构单元在构建折叠体方面具有更大的潜力. 此外, 本文还发现, 当NH与第二个氢键受体形成氢键时, 其和第一个氢键受体之间的氢键就被削弱了, 即在芳酰胺形成三中心氢键时, 2个氢键受体争相与NH形成氢键并取得了某种平衡.     

NaZnPO4催化碳酸二甲酯和丙氨酸“一锅法”合成N-羧基丙氨酸酸酐

以碳酸二甲酯（DMC）代替光气,一锅法合成α-氨基酸-N-羧酸酐（NCAs）是实现绿色制备多肽的重要途径.制备了酸碱协同催化剂NaZnPO₄,用该催化剂催化DMC和丙氨酸"一锅法"合成N-羧基丙氨酸酸酐（Ala-NCA）.在N,N-二甲基甲酰胺（DMF）溶剂中,150℃的反应条件反应8 h时,Ala-NCA的收率最高为46.84%,催化剂循环5次后收率仍达38.62%.NaZnPO₄中Zn²⁺和O-Na具有有效的酸碱协同催化作用,在反应过程中具有去质子化、精准酰基化和高效成环的作用.利用TG-MS-IR技术研究了催化剂表面上原料转化和中间体精准关环过程,并提出了可能的反应催化机理.     

Modification of 4-(2-pyridylazo)-resorcinol postcolumn reagent selectivity through competitive equilibria with chelating ligands

Aminopolycar☐ylate ligands were added to the 4-(2-pyridylazo)-resorcinol (PAR) postcolumn reagent to alter the reagent selectivity towards transition metals. Addition of ethylenediaminetetraacetic acid (EDTA) completely suppressed the reaction between PAR and the metal ions. Addition of 0.1 mM nitrilotriacetic acid (NTA) to 1 mM PAR lowered the response to specific transition metal ions, but completely suppressed the PAR response to the lanthanides. Increasing the NTA concentration to 8 mM resulted in complete suppression of the PAR response to all metal ions except Cu²⁺ and Co²⁺ for which the detection limits were 3 and 1 ng, respectively. The observed selectivity results from the slow rate of conversion of metal ions from the M(NTA)₂⁴⁻ form to M(PAR)₂.     

Ru(Ⅱ) Bipyridyl Complex and TiO2 Nanocomposite Based Biomolecule-free Photoelectrochemical Sensor for Highly Selective Determination of Ultra-trace Hg^2+ in Aqueous Systems

A biomolecule-free photoelectrochemical(PEC) probe(denoted as Ru-1) was designed, synthesized and coupled with TiO2 nanoparticles(NPs) for the highly sensitive and selective PEC detection of Hg^2+, a model analyte with hypertoxicity to both human health and ecosystem. The probe Ru-1 was designed with Ru(Ⅱ) bipyridyl complex as the chromophore, thiocyanate ligand as the recognition unit, and carboxylate group as the linkage site to connect Ru-1 to TiO2 nanoparticles. Under irradiation, Ru-1 shows strong affinity to TiO2 and good photophysical properties of strong visible light absorption, slow electron-hole(e-h^+) recombination, and fast photoelectron injection to TiO2 nanoparticles via the bridge of 4-(2,2-bipyridin)-4-yl-thiophene moiety. However, the specific coordination of Hg^2+ with Ru-1 via the thiol moiety in the thiocyanate enlarges the band gap of tlie complex and reduces the photocurrent significantly. The synergistic interaction between TiO2 nanoparticles and the Ru-1 complex led to a selective PEC sensing strategy for Hg^2+ detection. Detectable linear ranges from 10^-12 g/mL to 10^-7 g/mL and from 10^-7g/mL to 10^-3 g/mL were obtained without the interference from possibly co-existed metal ions. The good analytical performances indicate the chemical probe based biomolecule-free PEC platform may offer a new route for the detection of biologically and environmentally important small molecules.     

Preparation of Cerium Dioxide Functionalized Magnetic Layered Double Hydroxides for High-efficiency Phosphopeptide Enrichment

In this work, we prepared a material with magnetic nanoparticles (Fe₃O₄) as core, layered double hydroxides(LDHs) as affinity shell, and cerium dioxide(CeO₂) as functional molecules(denoted as Fe₃O₄@LDH-CeO₂). On the basis of combined immobilized metal ion affinity chromatography(IMAC) and metal oxide affinity chromatography(MOAC), Fe₃O₄@LDH-CeO₂ was used to enrich phosphopeptides with high efficiency. The material exhibited high selectivity(α-casein:β-casein:BSA=1:1:5000, mass ratio), high recovery(95.87%), and good reusability of 10 times adsorption- desorption experiments. The feasibility of Fe₃O₄@LDH-CeO₂ was further investigated by extracting phosphopeptides from biological samples(nonfat milk, serum, saliva, and A549 cell lysate).     

7种胺基键合硅胶的制备及其对重金属Pb2+的吸附

制备了氨丙基键合硅胶（SiO₂-N）、乙二胺-N-丙基键合硅胶（SiO₂-2N）、二乙烯三胺基键合硅胶（SiO₂-3N）、三乙烯四胺基键合硅胶（SiO₂-4N）、四乙烯五胺基键合硅胶（SiO₂-5N）、五乙烯六胺基键合硅胶（SiO₂-6N）和聚乙烯亚胺基键合硅胶（SiO₂-nN）,一步法制备的SiO₂-N和SiO₂-2N的胺基键合密度高达2.07 mmol/g和1.71mmol/g,两步法制备的SiO₂-nN的胺基键合密度为0.02mmol/g,其余胺基键合硅胶中胺基密度约为0.50mmol/g。这7种胺基键合硅胶被用于水溶液中常见重金属离子Pb²⁺的吸附研究。结果表明,在30℃条件下,分别加入10 mL 400 mg/L的Pb²⁺溶液（pH 5）和20 mg胺基键合硅胶进行吸附,10 h后,Pb²⁺吸附量达到最大,吸附过程符合Freundlich等温方程。SiO₂-N、SiO₂-2N、SiO₂-3N、SiO₂-4N、SiO₂-5N、SiO₂-6N和SiO₂-nN对Pb²⁺的吸附量依次为131.28、138.98、85.37、75.22、61.87、79.12和114.06 mg/g,这些胺基键合硅胶在吸附Pb²⁺方面均非常具有潜力。     

Quadruple-stranded Eu-helicate Assembled from Bis-β-diketonate: Its Stability Towards Metal Ions

Herein, we reported the synthesis and investigation of highly luminescent quadruple-stranded helicate (C₆H₁₆N)₄[Eu₂(MBDA)₄]₂^.3C₄H₁₀O·4C₂H₃N(1-Eu)[H₂MBDA=N-methyl-4,4'-bis(4,4,4-trifluoro-1,3-dioxobutyl)di- phenylamine] for its stability toward metal ions in the solution. The material was characterized via X-ray crystallographic technique, Fourier transform infrared(FTIR) spectroscopy and electrospray ionization quadrupole time-of- flight(ESI-TOF) mass spectrometry. The results on the luminescence quantum yields clearly demonstrate that the ligand can effectively sensitize the luminescence of the Eu³⁺ ions(Φ_overall=15%). Upon the addition of different metal ions(i. e., Ag⁺, Cd²⁺, Zn²⁺, Fe³⁺, Al³⁺ and Ni²⁺) to the CH₃CN solution of compound 1-Eu, the emission intensities of Eu³⁺ ions at 612 nm were affected to some extent, which could be attributed to the presence of ion exchanges between Eu³⁺ ions and the metals ions, and the result was confirmed by ESI-TOF mass spectrometry.     

Construction of a nano-rectangular Zn-Nd complex with near-infrared luminescent response towards metal ions

One 6-metal Zn-Nd complex[Zn₂Nd₄L₂(OAc)₁₀(OH)₂(CH₃OH)₂](1)with Schiff base ligand bis(3-methoxysalicylidene)ethylene-1,2-phenylenediamine(H₂L)was constructed,and it has nanoscale rectangular structure(8×11×28 A).Excited by ligand-centered absorption bands,1 shows NIRemission of Nd³⁺ion.Interestingly,1 exhibits lanthanide luminescent response towards metal ions,especially to alkali metal ions(Li⁺,Na⁺ and K⁺)at ppm level.     

Studies of the oxidation of iminodiacetic acid (IDA) and nitrilotriacetic acid (NTA) with lead dioxide suspension in nitric acid

The stoichiometry of the oxidation of IDA or NTA with lead dioxide suspension was studied by polarographic measurement and by derivative polarographic titration. One mole and two moles of Pb(IV) are reduced per mole of IDA and NTA respectively, with moderate speed at room temperature in nitric acid solutions. One mole each of carbon dioxide, formaldehyde and glycine are produced from the oxidation of 1 mole of IDA, and two moles of carbon dioxide, two moles of formaldehyde and one mole of glycine from 1 mole of NTA. The overall reaction in each case may be written as follows: Pb(IV) + IDA + H₂O → Pb(II) + CO₂ + HCHO + H₂NCH₂COOH + 2H⁺ 2Pb(IV) + NTA + 2H₂O → 2Pb(II) + 2CO₂ + 2HCHO + H₂NCH₂COOH + 4H⁺     

基于水杨醛席夫碱锌配合物交联稳定化荧光聚合物胶束的合成及其对铜离子的荧光响应性

以S-十二烷基-S'-(α,α'-二甲基-α″-乙酸)-三硫代碳酸酯(DMAT)为链转移剂、2-羟基-5-乙烯基苯甲醛(HVB)为单体,利用可逆加成-断裂链转移自由基聚合法(RAFT)合成结构明确、数均相对分子质量可控的水杨醛聚合物(PHVB)。将PHVB直接地与单端胺基功能化聚乙二醇(m PEG-NH2)按n(—NH2group)/n(—CHO group)=0.50投料进行醛-胺缩合反应,获得接枝率为50%的两亲性接枝水杨醛席夫碱聚合物PHVB-graft-PEG。采用凝胶渗透色谱仪(GPC)和核磁共振氢谱(1H NMR)对合成的聚合物的数均相对分子质量和结构进行了确证。将PHVB-graft-PEG直接地分散于无水乙醇中,自组装形成以聚乙烯水杨醛席夫碱为核、聚乙二醇为壳的胶束,然后以所得胶束为微反应器,与Zn(OAc)2进行配位反应得到外壳为可溶性链段PEG,内核为发光水杨醛席夫碱锌配合物的PHVB-graft-PEG/Zn~(2+)交联稳定化胶束。通过紫外-可见分光光谱(UV-Vis)、荧光发射光谱(FLL)、动态光散射(DLS)和透射电子显微镜(TEM)分别对胶束的交联稳定化过程进行了表征。研究结果表明,经交联稳定化后,PHVB-graft-PEG/Zn~(2+)胶束在干燥后仍可在水和常见有机溶剂中再分散形成粒径大小约为100 nm、在约460 nm处发射出蓝光荧光的纳米粒子,并且可作为荧光传感器,在水溶液中对Cu~(2+)离子进行选择性识别,其荧光淬灭率与Cu~(2+)离子浓度(0~50μmol/L范围内)呈线性关系,最低检测下限至0.5μmol/L,而其它共存离子如Cd~(2+)、Mg~(2+)、Ni~(2+)、Pb~(2+)、Ca~(2+)、Hg~(2+)、Al3+、Mn~(2+)等对Cu~(2+)离子的荧光响应性没有干扰,即可实现对Cu~(2+)离子进行定量检测。     

An improved Brust’s procedure for preparing alkylamine stabilized Pt, Ru nanoparticles

An improved method to prepare alkylamine-stabilized Pt and Ru nanoparticles based on the original Brust’s procedure [J. Chem. Soc., Chem. Commun. (1994) 801] has been developed. The new method involves, firstly, mixing an aqueous solution of metal salts such as PtCl₆²⁻, PtCl₄²⁻ or Ru³⁺ with an ethanol solution of dodecylamine; extracting the metal ions into a toluene layer; and finally reducing the metal ions to their zero valent states using NaBH₄. Alkylamine-stabilized Pt nanoparticles prepared this way had a polyhedral or wormlike appearance, depending closely on the chemical nature of the metal precursor salts being used. On the contrary, dodecylamine-stabilized ruthenium nanoparticles were predominantly spherical. The particle formation and growth processes in the hydrocarbon layer could be influenced by the different ways dodecylamine was bound to H₂PtCl₆, K₂PtCl₄ or RuCl₃ at the precursor stage.     

A highly selective magnetic sensor with functionalized Fe/Fe3O4 nanoparticles for detection of Pb2+

A magnetic sensor for detection of Pb~(2+) has been developed based on Fe/Fe_3O_4 nanoparticles modified by3-(3,4-dihydroxyphenyl)propionic acid(DHCA). The carboxyl groups of DHCA have a strong affinity to coordination behavior of Pb~(2+) thus inducing the transformation of Fe/Fe_3O_4 nanoparticles from a dispersed to an aggregated state with a corresponding decrease, then increase in transverse relaxation time(T_2) of the surrounding water protons. Upon addition of the different concentrations of Pb~(2+) to an aq. solution of DHCA functionalized Fe/Fe_3O_4 nanoparticles(DHCA-Fe/Fe_3O_4 NPs)([Fe] = 90 mmol/L), the change of T_2 values display a good linear relationship with the concentration of Pb~(2+) from 40 μmol/L to 100 μmol/L and from 130 μmol/L to 200 μmol/L, respectively. Owing to the especially strong interaction between DHCA and Pb~(2+), DHCA-Fe/Fe_3O_4 NPs exhibited a high selectivity over other metal ions.