Mn掺杂ZnS量子点荧光猝灭法测定双酚A

本文采用水热法分别制备了Mn2+掺杂ZnS量子点和聚苯乙烯-甲基丙烯酸聚合物,超声辅助包裹法制备双酚A印迹型量子点纳米微球复合物。通过量子点荧光猝灭效应对双酚A进行定量分析。本实验考察了量子点共聚物与双酚A在不同pH值的缓冲溶液中作用及不同反应时间对量子点荧光猝灭效率的影响。实验结果表明,在pH10.5的碱性介质及反应时间30min条件下,方法的线性范围为60～820 ng.mL-1,检出限为0.02μg.mL-1。该方法用于环境水样中双酚A的测定,结果满意。     

核壳式CdSe/ZnS量子点对邻苯二甲酸二丁酯的快速高灵敏荧光测定

用水热反应法制备了核壳式CdSe/ZnS量子点并用透射电镜进行形貌表征,将该量子点作为荧光探针,基于邻苯二甲酸二丁酯(DBP)的荧光增强效应,建立了一种快速测定DBP的方法。在最优条件(pH7.0,反应时间15 min,水作溶剂)下,DBP对CdSe/ZnS量子点的荧光增强作用最显著,在1.0～20.0μg/L范围内荧光信号强度与DBP浓度的对数呈线性关系,检出限为0.21μg/L,相关系数R²为0.99。该方法可用于白酒中DBP的含量测定,与现有标准方法GC-MS比较,具有高的检测灵敏度和准确性。     

11-巯基烷酸修饰的核/壳量子点CdSe/ZnS的合成及分析应用研究

以11-巯基烷酸作为修饰剂,在水相中合成了CdSe/ZnS量子点荧光探针(QDs),并将其用于测定牛血清白蛋白.从透射电子显微镜看到该量子点外观近似球形,粒径约为15 nm.该核/壳量子点紫外吸收峰为460 nm,荧光发射峰为548nm,其荧光强度比单核量子点增强2.1倍.而且在至少40 d里,荧光强度基本保持稳定.在最佳条件下,实验表明了CdSe/ZnS QDs-BSA体系的荧光强度与BSA浓度呈线性关系,线性响应范围为10.0～50.0 mg/L,线性方程为△F=141.29 1.259c(c:mg/L),r=0.999 1.该方法应用于合成样品的测定中得到满意的结果.     

基于MPA包覆的Mn掺杂ZnS量子点室温磷光法检测甲硝唑

以3-巯基丙酸(MPA)包覆的Mn掺杂Zn S量子点作为室温磷光探针,基于甲硝唑对Mn掺杂Zn S量子点磷光猝灭效应,建立了一种简单、快速测定甲硝唑含量的磷光检测方法。在最佳实验条件下,所建立的方法检测范围为1.16²32μmol/L,检出限为0.09μmol/L,可用于实际药品中甲硝唑的快速标定。     

基于MPA包覆的Mn掺杂ZnS量子点室温磷光法检测甲硝唑

以3-巯基丙酸(MPA)包覆的Mn掺杂Zn S量子点作为室温磷光探针,基于甲硝唑对Mn掺杂Zn S量子点磷光猝灭效应,建立了一种简单、快速测定甲硝唑含量的磷光检测方法。在最佳实验条件下,所建立的方法检测范围为1.16~232μmol/L,检出限为0.09μmol/L,可用于实际药品中甲硝唑的快速标定。     

ZnS量子点/纤维素复合材料的制备及光催化性能

采用硝酸锌和硫化钠为原料,通过水热法制备ZnS量子点的过程中同步负载于纤维素纤维上,得到具有优良性能的光催化纤维素纤维。探究了前驱体溶液浓度、水热温度、水热时间等对量子点纤维素材料的荧光强度、量子点负载率及光催化性能的影响。结果表明,最佳反应条件为:Zn⁽²⁺⁾浓度为75 mmol/L,反应温度180℃,反应时间12 h。在此条件下,ZnS量子点的负载率为9.4%。浓度10 mg/L的甲基橙(MO)模型污染物,量子点纤维素材料添加量2.5 g/L,以紫外灯(λ=365 nm)为光源,30 min内其光催化降解效率可达到83%。量子点纤维素材料具有良好的循环使用性能,经循环使用5次后,30 min内甲基橙的光催化降解率仍可达到59%。     

ZnS量子点/纤维素复合材料的制备及光催化性能

采用硝酸锌和硫化钠为原料,通过水热法制备ZnS量子点的过程中同步负载于纤维素纤维上,得到具有优良性能的光催化纤维素纤维。探究了前驱体溶液浓度、水热温度、水热时间等对量子点纤维素材料的荧光强度、量子点负载率及光催化性能的影响。结果表明,最佳反应条件为:Zn~(2+)浓度为75 mmol/L,反应温度180℃,反应时间12 h。在此条件下,ZnS量子点的负载率为9.4%。浓度10 mg/L的甲基橙(MO)模型污染物,量子点纤维素材料添加量2.5 g/L,以紫外灯(λ=365 nm)为光源,30 min内其光催化降解效率可达到83%。量子点纤维素材料具有良好的循环使用性能,经循环使用5次后,30 min内甲基橙的光催化降解率仍可达到59%。     

Mn掺杂ZnS量子点的合成及其水溶性修饰

利用苯乙烯-甲基丙烯酸共聚物对疏水性的Mn掺杂的ZnS量子点(ZnS:Mn QDs)进行包覆,得到了发光效率更好的水溶性量子点复合物(QDs-NIP)。用紫外分光光度计(UV-vis),荧光分光光度计(PL)和红外分光光度计(FTIR)对其进行结构及光学的表征。结果发现,红外光谱图证明我们成功合成了量子点、共聚物的复合纳米粒子,且其水溶后的复合纳米粒子仍能拥有高的发光效率;我们得到的高发光效率,水溶性好的ZnS:Mn QDs为后续的细胞成像,生物传感,细胞标记等打下了好的基础。     

CdSe与CdSe/ZnS核壳型量子点的制备方法与展望

CdSe及CdSe/ZnS量子点具有特殊的发光性质性质,它们在生物荧光探针、生物芯片、激光器、光电子器件和光催化等领域具有广泛的应用,现在越来越多的研究者更加关注它们在生命科学研究中起到得定性和定量标识生物分子和细胞作用。本文对几种制备CdSe及CdSe/ZnS量子点的方法进行了简单的综述,分别介绍了CdSe的水相、有机相以及绿色合成法,CdSe/ZnS量子点的热注入有机金属法和水相合成法,对这几种方法的优缺点进行了概述,并对其前景做了展望。     

基于CdSe/ZnS量子点荧光猝灭法测定硫胺素

以CdSe/ZnS量子点为荧光探针,基于硫胺素(VB1)与CdSe/ZnS量子点间通过静电作用而有效猝灭CdSe/ZnS量子点荧光强度的机制,建立了一种可快速测定VB1的荧光检测方法.在最优实验条件下(pH 7.4,反应时间25 min),硫胺素(VB1)浓度在0.01 ～1 μmol/L时,CdSe/ZnS量子点荧光猝灭变化强度与硫胺素(VB1)浓度呈良好的线性关系:F0/F=0.67cCB1+1.05(R=0.999 2),方法检出限为5.1×10-3 μmol/L,相对标准偏差为1.09％.该方法可用于人体尿样中VB1的快速测定.     

聚乙二醇改性聚乳酸及其在药物载体中的应用

综述了聚乙二醇改性聚乳酸及其端基化的制备方法,介绍了聚乙二醇-聚乳酸嵌段共聚物作为药物载体的研究进展,并对今后的研究进行了展望.     

聚马来松香酸乙二酯的合成

以天然产物松香酸为原料,分别经马来酸和三氯化磷化学改性得到马来松香酰氯单体,马来松香酰氯单体在无水条件下与乙二醇聚合得到功能性马来松香酸乙二酯,用红外光谱对聚合产物进行了表征。通过正交实验研究了反应物摩尔比、反应时间、反应温度以及催化剂用量对聚合反应的影响,结果表明,在乙二醇与马来松香酰氯的摩尔比为1：1、反应时间4h、反应温度40℃、催化荆用量1％的条件下,聚合反应达到最佳,产率为85％,聚合产物分子量在5万到7万之间。     

化学交联聚乙二醇水凝胶的制备方法

对化学交联聚乙二醇基水凝胶的研究进展进行了综述.介绍了该类水凝胶的制备方法,包括几种常见的前体制备方法和常用的交联方法,并讨论了影响水凝胶溶胀性能和力学性能的几种因素.     

含PEG组分的聚(N-异丙基丙烯酰胺)水凝胶的制备研究

首先合成了二丙烯酰基封端的聚乙二醇(PEG)大分子交联剂,然后使其与N,N-亚甲基双丙烯酰胺(BIS)和(N-异丙基丙烯酰胺)(NIPAM)单体进行交联反应,制备了PNIPAM-co-PEG-co-BIS水凝胶。与通常的PNIPAM-co-BIS凝胶比较,PNIPAM-co-PEG-co-BIS凝胶显示了明显加速的去溶胀动力学。这种加速的去溶胀性能归因于凝胶中的PEG组分为凝胶提供了亲水通道,在缩水过程中有利于凝胶的脱水。     

基于苯胺增塑的聚乙二醇固态电解质染料敏化太阳能电池

对聚乙二醇固态电解质进行了苯胺增塑处理。虽然为NaI的不良溶剂,将苯胺掺入到固态电解质中对提高NaI浓度贡献不大,但是由于苯胺分子上的胺基与聚乙二醇主链上醚基团的相互作用破坏了晶态结构,增大自由体积有利于离子迁移,从而能大幅提高离子电导率。同时,Lewis碱性苯胺分子能有效抑制染料敏化太阳能电池(DSSC)暗反应,减少光生电子损耗并提高开路电压。含这种固态电解质的DSSC短路电流、开路电压、填充因子及光电转换效率均高于未增塑的聚乙二醇固态电解质DSSC。     

乙二醇铝催化酯化法合成聚丁二酸乙二醇酯

聚丁二酸乙二醇酯(PES)具有优异的力学性能和生物降解性能,在可生物降解塑料领域具有广泛的应用前景。以乙二醇铝为催化剂,催化丁二酸和乙二醇直接酯化缩聚合成了高分子量聚丁二酸乙二醇酯(PES)。采用FT-IR和1H-NMR对催化剂和合成聚合物的结构进行了表征,系统分析了催化剂浓度、聚合反应温度和时间对聚合反应的影响。经常压酯交换后获得的预聚体,在240℃条件下,缩聚4 h后,合成PES的特性黏数[η]可达到0.684 dL/g,重均分子量Mw和数均分子量Mn分别可以达到78632和47945,相对分子质量分布系数PDI值为1.64。乙二醇铝体系中获得的PES聚合物分子量与商业锑系和钛系催化体系中合成聚合物分子量相当,具有广泛工业化应用前景。     

Fabrication and Characterization of Macroporous Poly(Ethylene Glycol) Hydrogels Generated by Several Types of Porogens

Polymer scaffolds play an important role in tissue engineering applications. Poly(ethylene glycol) based hydrogels have received a lot of attention in this field because of their high biocompatibility and ease of processing. However, in many cases they do not exhibit proper tissue invasion and nutrient transport because of their dense structure. In the present work, several approaches were developed and compared to each other to produce interconnected macroporous poly(ethylene glycol) hydrogels by including different types of porogens in the photocrosslinking reaction. The swelling capacity of the resulting hydrogels was analyzed and compared to non-porous hydrogel samples. Moreover, the obtained materials were characterized by means of mechanical properties and porosity using rheometry, scanning electron microscopy, and mercury intrusion porosimetry. Results showed that interconnected and uniform pores were obtained when a porogen template was used during hydrogel fabrication by photocrosslinking. On the other side, when the porogen particles were dispersed into the macromer solution before matrix photocrosslinking the interconnexion was negligible. The templates must be dissolved before the hydrogel's cell-seeding in vitro, while the dispersed porogen can be used in situ in the in vitro seeding tests.     

间苯二甲酸改性PET的结晶行为研究

应用 DSC研究了间苯二甲酸 (IPA)改性 PET的结晶行为。结果表明 :由于第三单体破坏了 PET大分子结构的规整性 ,导致改性聚酯熔点下降 ,冷结晶温度上升 ,热结晶温度下降 ;与常规 PET相比 ,较慢的冷却速度就可使熔融状态的改性 PET保持无定形状态。     

Shape Memory and Physical Properties of Composites of Polyethylene Oxide/Poly(Propylene Glycol)-Block-Poly(Ethylene Glycol)-Block-Poly(Propylene Glycol)/2,4-Toluene Diisocyanate,Polypyrrole, and Modified MWCNT

Structural variation and its influence on morphology, mechanical, thermal, and electrical conductivity properties of polyethylene oxide/poly(propylene glycol)-block-poly(ethylene glycol)-block-poly(propylene glycol)/2,4-toluene diisocyanate/polypyrrole (PEO/P(P-E-P)G/TDI/PPy) blends and nanocomposites with varying PPy content were reported. The chemical and fundamental linkages were confirmed by FTIR. SEM micrographs demonstrated homogeneous PEO/P(P-E-P)G/TDI/PPy blend formation and globular morphology for nanocomposites. The mechanical and DSC parameters were found to increase systematically with increasing PPy content in blend films. While for nanocomposites, better results were observed for 0.1% PPy content. Maximum electrical conductivity and good shape recovery of 94% was obtained for the nanocomposite with 1% PPy content.     

Bioconjugation of (CdSe)ZnS Quantum Dots Using a Genetically Engineered Multiple Polyhistidine Tagged Cohesin/Dockerin Protein Polymer

Summary: We have constructed bioconjugates consisting of genetically modified cohesin/dockerin protein polymers combined with (CdSe)ZnS colloidal quantum dots. This recombinant protein contains fusions of Clostridium thermocellum cellulosomal cohesin and dockerin domains and a C‐terminal 6×‐histidine tag. These unique cohesin/dockerin monomeric building blocks (ca. 60 kDa) were allowed to self‐assemble, yielding oligomers and polymers, which were subsequently characterized by high‐pressure size exclusion chromatography (HPSEC). The C‐terminal 6×‐His tags from each monomer facilitate binding to the quantum dot surface chemistry while mix the protein polymers with water‐soluble QDs at neutral pH. Using HPSEC, we were able to fractionate the reaction mixture into two major distributions of bioconjugate species. Scanning transmission electron microscopy (STEM) and photoluminescence spectroscopy (PL) were employed to characterize the components from these chromatographic fractions. The fraction containing the larger bioconjugates contained clusters of quantum dots surrounded by protein polymers with an estimated radius of 190 ± 30 Å and an apparent molecular weight of 8 000 ± 3 000 kDa. The STEM images from the fraction containing the smaller species were amenable to detailed analysis and graphical simulation that revealed species containing one, two, or three quantum dots surrounded by 10, 15, or 18 protein monomers, respectively. Our data demonstrate strong binding coefficients not only between the protein monomers to form polymers, but also with the (CdSe)ZnS colloidal quantum dots and thus provides a method of producing stable, water‐soluble luminescent quantum dot bioconjugates. PL spectroscopic analysis shows that the samples from both chromatographic fractions have strong excitonic emission with a peak at ca. 2.2 eV (562 nm).

STEM images of cohesin/dockerin protein polymer‐QD conjugates from the HPSEC elution peak. A represents a typical STEM image 512 × 512 nm scanning field showing the conjugates containing 1, 2, and 3 QDs with 10, 15, and 18 protein monomers surrounded, respectively.