分级结构氮掺杂碳纳米笼担载的铂基高效甲醇氧化电催化剂

高性能低成本的担载型铂基催化剂是直接甲醇燃料电池(DMFC)实用化过程中的一大挑战.利用高比表面积、高稳定性、容易负载金属的载体实现 Pt颗粒的高度分散,既可提高催化剂的催化性能,又可提高 Pt的利用率以降低成本,是担载型 Pt基催化剂实用化的有效途径.碳材料是一种常用的催化剂载体,近年来我们课题组发展了一种高性能的碳纳米笼材料,并可通过异原子掺杂调变其表面性能,提高其活性和负载能力.我们采用原位氧化镁模板法制备氮掺杂碳纳米笼：以具有多级结构的碱式碳酸镁作为氧化镁模板的前体,吡啶为碳源和氮源,经高温热解沉积,在原位形成的氧化镁模板表面形成氮掺杂的石墨化碳纳米薄层;经稀盐酸浸泡并洗涤,获得高纯度的氮掺杂碳纳米笼.氮掺杂碳纳米笼具有分等级的微纳米结构、高导电性、高比表面积和可调变的孔结构,结合表面氮原子的锚钉作用,氮掺杂碳纳米笼有望成为电化学催化剂 Pt的优良载体.
　　在前期研究基础上,本文探索多级结构氮掺杂碳纳米笼(hNCNC)作为新型载体负载 Pt的能力,并评价所构建的负载型催化剂 Pt/hNCNC的电催化性能.通过简便的微波辅助多元醇还原法,将氯铂酸还原成 Pt纳米粒子负载于 hNCNC的表面.为了揭示氮掺杂的效应,我们对比研究了具有相似分级结构但无掺杂的碳纳米笼(hCNC)以及商业化活性炭(Val-can XC-72)作为载体的情况.经热重(TG)和 X射线光电子能谱(XPS)分析,三种催化剂 Pt/hNCNC、Pt/hCNC和 Pt/XC-72的负载量均接近理论负载量(23.1 wt%),都主要以金属态存在.然而,扫描电子显微镜(SEM)和透射电子显微镜(TEM)结果表明, Pt/hNCNC的 Pt分散状态优于 Pt/hCNC,更远优于 Pt/XC-72. Pt/hNCNC的平均 Pt粒径最小,仅约3.3 nm.这种良好的分散状态主要得益于氮原子掺杂,高负电性的氮原子改变了局域的表面极性,有利于 Pt颗粒的成核,也有利于固定 Pt颗粒.
　　由于 hNCNC对 Pt的优异分散能力, Pt/hNCNC表现出高的电化学活性面积.氢吸附和一氧化碳溶出伏安曲线表明, Pt/hNCNC的电化学活性面积高于 Pt/hCNC和 Pt/XC-72,这与显微观察和 X射线衍射(XRD)结果相吻合. Pt/hNCNC展现出优异的甲醇电催化氧化活性和高稳定性,其催化电流明显高于 Pt/hCNC和 Pt/XC-72,电流衰减亦慢于 Pt/hCNC和 Pt/XC-72. hNCNC的分级微纳米结构有利于孔内传质和电子输运,从而提高反应速度. hNCNC的氮掺杂有利于 Pt在载体表面的分散,增强了载体-金属相互作用,提高了电化学活性面积和催化活性.为了进一步考察 hNCNC对 Pt的负载能力,本文还考察了高负载量 Pt/hNCNC的性能.在负载量高达60 wt%时, Pt/hNCNC中的 Pt颗粒仍无明显聚集,其甲醇氧化电流增加了30%,可以有效提高 DMFC的输出电流密度.
　　综上可见, hNCNC可以有效分散并稳定 Pt颗粒,从而提高电化学活性面积和甲醇电催化氧化活性,优于未掺杂的碳纳米笼和传统碳材料,展示了 hNCNC高分散 Pt颗粒用作 DMFC的高效阳极催化剂的重要前景,也表明 hNCNC有望成为应用广泛的新型载体.     

钙钛矿材料组分调控策略及其光电器件性能研究进展

近年来，钙钛矿太阳电池的光电转换效率取得了爆发式增长，这与电池中钙钛矿薄膜的制备工艺和材料组分密切相关.关于钙钛矿薄膜的制备方法，相关的研究报道及综述较多，然而钙钛矿材料组分调控方面的研究梳理工作相对缺乏.本综述总结了近年来不同组分体系钙钛矿材料的研究进展，包括有机无机铅卤钙钛矿、全无机铅卤钙钛矿、少铅钙钛矿以及无铅钙钛矿.重点介绍了不同体系中具有代表性的材料组分及其对器件性能的影响，旨在梳理通过组分调控提高钙钛矿电池的效率及稳定性的研究思路，最终实现商业化应用.     

Guanidinoamidized linear polyethyleneimine for gene delivery

Guanidine was introduced to low molecular weight linear polyethyleneimine(LPEI) via amide groups, to explore the effect of both guanidine degree and pendant chain length on its transfection behavior. The resulting guanidinoamidized LPEIs(GLPEIs) could dramatically reduce LPEI's toxicity, enhance its DNA-packaging capability, cellular uptake and therefore transfection efficiency. These polyplexes were taken up very efficiently via caveolae-mediated endocytosis and their transfection efficiencies in ovarian cancer cells were significantly improved compared to native LPEI10 k polyplexes. Among these GLPEIs, LPEI-C3-G100 showed higher DNA affinity even than LPEI25 k and the highest transfection efficiency, probably due to the optimization of polymer chain flexibility. Of notice, LPEI-C3-G100 polyplexes could more effectively accumulate into cytoplasm than LPEI25 k, although the transfection efficiency of LPEI-C3-G100 polyplexes was not superior to that of LPEI25 k polyplexes, which would be probably attributed to the more efficient release of LPEI25 k polyplexes than LPEI-C3-G100 polyplexes in the cytoplasm.     

铂类抗癌药物的多功能纳米递送体系

以顺铂为代表的小分子铂类抗癌药物是临床应用的一线化疗药物,但其严重的毒副作用和难以克服的耐药性限制了铂类药物的临床应用和研发。运用纳米药物递送技术可以实现药物的靶向递送和可控释放,来提高药物的生物利用度,降低药物的毒副作用以及耐药性,为癌症的治疗带来新的希望。此外,丰富多样的纳米递送体系易于实现药物与具有生物学活性试剂的共运输,从而为各种治疗策略以及诊疗策略的联用提供可能,为最终实现癌症的精准治疗展现广阔前景。本文从靶向递药、药物可控释放、联合治疗、诊疗一体化四个方面对铂类抗癌药物的多功能纳米递送体系在癌症治疗中的最新研究进展进行综述,同时通过列举最新研究成果,展示了新材料、新技术以及新颖设计思想在铂基纳米递送体系中的应用。     

超高效液相色谱-四极杆-飞行时间质谱法定性筛查保健食品中西地那非及其相关功效类非法添加化合物

建立了超高效液相色谱-四极杆-飞行时间质谱（UPLC-Q-TOF-MS）定性筛查102种西地那非及其相关功效化合物的方法。甲醇超声提取样品;采用Agilent Poroshell 120 SB-C18色谱柱（75 mm×3.0 mm,2.7 μm）,以0.1%（v/v）甲酸水溶液-乙腈为流动相梯度洗脱,流速0.4 mL/min;采用电喷雾离子（ESI）源,Q-TOF-MS作检测器,正离子模式检测;与对照品保留时间、母离子及碎片离子精确相对分子质量、元素组成比对,准确定性。西地那非等100种化合物在10种基质中的检出限为0.1~50 mg/kg或0.1~50 mg/L。并分类归纳了文中涉及的98种磷酸二酯酶5抑制剂质谱碎片裂解规律,为可疑物的识别和鉴定提供参考。该方法已应用于实际样品的测定,检出19种化合物,有效打击了非法添加行为。     

Quantitation of seven polyoxypregnane glycosides in Marsdenia tenacissima using reversed-phase high-performance liquid chromatography-evaporative light-scattering detection

A high-performance liquid chromatography coupled with an evaporative light scattering detector (HPLC-ELSD) has been developed for the simultaneous determination of seven polyoxypregnane glycosides, tenacissosides A, B, G, H, I and marsdenosides C, G, in the stem of Marsdenia tenacissima, a Chinese herbal medicine. With a C18 analytical column, the analytes were separated efficiently using methanol-water as the mobile phase in a gradient program. The method limits of detection ranged from ca. 0.3 microg for marsdenoside C to ca. 0.5 microg for marsdenoside G and the method limits of quantitation from 1.0 microg for marsdenoside C to 1.7 microg for marsdenoside G, respectively. The intra- and inter-day precisions of the method were evaluated and all were less than 4%. All the recoveries for the spiked analytes exceeded 90%. This method was successfully used to analyze 19 samples of the stem of M. tenacissima.     

7种氨基醇类药物在替考拉宁柱上的对映体分离

在替考拉宁手性柱上对阿替洛尔、美托洛尔、富马酸比索洛尔、普萘洛尔、异丙肾上腺素、沙丁胺醇及拉贝洛尔7种氨基醇类药物进行了对映体分离的研究.考察了流动相甲醇中添加少量酸碱以及酸碱不同比例对7种溶质的对映体分离的影响.固定极性有机相甲醇中冰醋酸和三乙胺的比例为1:1时,手性溶质的保留因子均随着流动相中冰醋酸/三乙胺含量的增加而减小,分离因子(α)基本保持不变,分离度减小.这可能是因为过量的酸增加了流动相的极性,使溶质较快被洗脱.在不加冰醋酸的情况下,除拉贝洛尔外,随着三乙胺浓度的增加,容量因子均减少,分离因子基本不变,分离度减小.这可能是因为三乙胺的增加使流动相的极性增加,溶质与手性固定相间的氢键减弱.结果表明:冰醋酸和三乙胺的比例并不影响手性分离的实质.     

基于裂开型核酸适配体的液晶生物传感检测三磷酸腺苷

利用“适配体-目标分子-适配体”的“三明治”夹心方式构建液晶生物传感检测三磷酸腺苷(ATP). 将ATP核酸适配体片段作为捕获探针固定在经TEA/DMOAP混合组装膜修饰的玻片基底表面, 当ATP存在时, 裂开的两部分核酸适配体与ATP结合形成双链结构, 有效诱导液晶分子取向发生变化从而引起光学信号的亮度及颜色发生变化, 实现对ATP的检测, 该方法在ATP浓度为10 nmol/L时仍可观测到明显的光学信号变化. 这种“适配体-目标分子-适配体”的“三明治”夹心式液晶生物传感方法具有无需标记, 操作简单等特点, 在快速检测小分子等物质领域中有广泛的应用前景.     

Long-term follow-up analysis of zolpidem in fingernails after a single oral dose

The determination of xenobiotics in keratinized matrices, such as nails and hair, has received considerable attention because of the relatively long detection window for compounds. The distribution of xenobiotics in fingernails, unlike hair, was equivocal. The main aim of this study was to use follow-up surveys to measure zolpidem profiles in nails after subjects consumed a single dose of the drug. In addition, the zolpidem concentrations in nails were compared with data for different biosamples, such as hair and blood from previous work. With these preconditions, a high-performance liquid chromatography–tandem mass spectrometry method was developed and validated for the determination of zolpidem in nails. Nails underwent alkaline hydrolysis and were extracted with diethyl ether. A Capcell Pak C18 MGII column was used to separate the target compound, and an API 4000 Qtrap mass spectrometer was used as a detector. The results for nail samples from seven subjects who had taken a single 10 mg zolpidem dose were significant: two relatively high zolpidem concentrations were observed in the long-term follow-up analysis of nails. The zolpidem concentration was less than 1.74 pg/mg and less than 3.29 pg/mg in fingernails and toenails, respectively. The subsequent peak concentration of zolpidem was observed between 10 and 15 weeks after each subject took a single dose of the drug. This result suggested that the germinal matrix area was a primary in vivo pathway for zolpidem secretion into the nail. The analysis of biosamples, such as nails, may be a useful adjunct to conventional methods of drug testing and hair analysis. Further research is needed concerning the contamination risk in analysis of nail biosamples.     

pH响应性P(MMA-co-MAA-co-HEMA)微凝胶的制备及其性能

利用预乳化乳液法制备了不同单体配比的聚(甲基丙烯酸甲酯-co-甲基丙烯酸-co-甲基丙烯酸羟乙酯)(P(MMA-co-MAA-co-HEMA))微凝胶分散液;采用透射电子显微镜、动态光散射仪研究了微凝胶的微观形态、粒径大小及其溶胀率;利用试管倒转法对微凝胶分散液的凝胶化相转变行为进行了研究,借助椎板流变仪考察了所形成胶态凝胶的储能模量与单体配比、微凝胶分散液浓度和温度的关系.结果表明,所制备的微凝胶的数均粒径为90 nm左右,当MMA与MAA的投料质量不变时,随着HEMA含量的增加,分散液凝胶化所需的临界最小浓度增大,临界最大pH值减小,胶态凝胶的储能模量增加.当保持单体MMA与HEMA的投料质量不变时,随着单体MAA投料质量的增多,微凝胶的数均粒径和溶胀率增大,胶态凝胶的储能模量先升高后降低;当MAA占单体总摩尔数的25%时,浓度为15 wt%的微凝胶分散液在扫描频率为100 rad/s时,胶态凝胶的储能模量最高可达2×104Pa.这类微凝胶分散液在组织工程支架材料方面有潜在的应用价值.