Solar‐Energy‐Driven Photoelectrochemical Biosensing Using TiO2 Nanowires

Photoelectrochemical sensing represents a unique means for chemical and biological detection, with foci of optimizing semiconductor composition and electronic structures, surface functionalization layers, and chemical detection methods. Here, we have briefly discussed our recent developments of TiO₂ nanowire‐based photoelectrochemical sensing, with particular emphasis on three main detection mechanisms and corresponding examples. We have also demonstrated the use of the photoelectrochemical sensing of real‐time molecular reaction kinetic measurements, as well as direct interfacing of living cells and probing of cellular functions.     

Selective Probing of Gaseous Ammonia Using Red‐Emitting Carbon Dots Based on an Interfacial Response Mechanism

Solid‐state fluorescence sensing is one of the most appealing detection techniques because of its simplicity and convenience in practical operation. Herein, we report the development of a red‐emitting carbon dots (RCDs)‐based material as a solid‐state fluorescence sensor for the selective probing of gaseous ammonia. The RCDs were prepared by a low‐cost, one‐step carbonization method using sugar cane bagasse as the carbon precursor. The pristine RCDs were then directly coated on polyvinylidene fluoride membrane to produce a new fluorescence sensor capable of selectively distinguishing toxic gaseous ammonia from other analyte vapors through sensitive fluorescence quenching with a low detection limit. More importantly, the interfacial response mechanism occurring on the surface of the RCDs has been studied by X‐ray photoelectron spectroscopy, Fourier‐transform infrared spectroscopy, and Raman measurements. The results indicate that fluorescence quenching in the RCDs might result from ammonia‐induced Michael addition through insertion of N into the C?C group and deprotonation of the carboxyl group. To the best of our knowledge, this is the first report that provides clear insight into the mechanism of surface chemistry on CDs in the solid state.     

氧化石墨烯增容尼龙6/聚苯乙烯共混体系的研究

氧化石墨烯(GO)亲水性的边缘和疏水性的中间片层使其具有两亲特性.利用GO的这种特性,将其加入尼龙6(PA6)/聚苯乙烯(PS)的共混体系,以提高PA6和PS的相容性.通过两步法制备了PA6/PS/GO共混物,研究了GO对PA6/PS共混材料结构形态与力学性能的影响,并对其增容机理进行了探讨.扫描电镜(SEM)结果表明,添加GO后,共混材料的分散相尺寸明显变小,分散更为均匀,少量的GO即可达到良好的增容效果.动态力学性能(DMA)测试进一步证明了GO对PA6/PS共混物具有一定的增容性.理论计算也表明PS/GO共混物和PA6具有更接近的表面自由能和较低的界面自由能.添加GO后共混物材料的拉伸性能和韧性明显提高.GO添加量为0.1 wt％时,共混材料的断裂伸长率较未添加GO的共混材料提高了170％,断裂能也提高了近240％.     

以3,5-二硝基苯甲酸和吡唑为配体的Ni(Ⅱ),Co(Ⅱ)配合物的合成与晶体结构

以3,5-二硝基苯甲酸(3,5-Hdnbc)和吡唑(pz)为配体与Co2+和Ni 2+反应,得到了2个新的配合物[Co(3,5-dnbc)2(pz)2(H2O)2](1)和[Ni(3,5-dnbc)2(pz)4](2).用元素分析、红外光谱对其进行了表征,并用单晶X-射线衍射测定了配合物的晶体结构;配合物1和2均为单核分子,配合物1通过分子内和分子间氢键形成三维网络超分子结构,而配合物2中只存在分子内氢键.     

X射线荧光光谱法快速测定铜基催化剂中金属含量

本文使用X射线荧光光谱仪,采用人工制备标样,以粉末直接压片和经验系数校正基体效应的方法,建立了铜基催化剂中CuO、ZnO和Al2O3含量的快速测定方法。考察了样品厚度的影响及方法的精密度和准确度。该法待测元素线性范围较宽,分别为:CuO:13.0%~97.0%,ZnO:0~63.0%,Al2O3:0~25.0%,且相关系数均大于0.99。测定各元素的相对标准偏差均小于0.3%,且测定结果与化学滴定分析结果吻合。该方法快速、简便,可应用于工业生产质量监控。     

A Preloaded Amorphous Calcium Carbonate/Doxorubicin@Silica Nanoreactor for pH‐Responsive Delivery of an Anticancer Drug

Biomedical applications of nontoxic amorphous calcium carbonate (ACC) nanoparticles have mainly been restricted because of their aqueous instability. To improve their stability in physiological environments while retaining their pH‐responsiveness, a novel nanoreactor of ACC–doxorubicin (DOX)@silica was developed for drug delivery for use in cancer therapy. As a result of its rationally engineered structure, this nanoreactor maintains a low drug leakage in physiological and lysosomal/endosomal environments, and responds specifically to pH 6.5 to release the drug. This unique ACC–DOX@silica nanoreactor releases DOX precisely in the weakly acidic microenvironment of cancer cells and results in efficient cell death, thus showing its great potential as a desirable chemotherapeutic nanosystem for cancer therapy.     

Graphene Liquid Marbles as Photothermal Miniature Reactors for Reaction Kinetics Modulation

We demonstrate the fabrication of graphene liquid marbles as photothermal miniature reactors with precise temperature control for reaction kinetics modulation. Graphene liquid marbles show rapid and highly reproducible photothermal behavior while maintaining their excellent mechanical robustness. By tuning the applied laser power, swift regulation of graphene liquid marble’s surface temperature between 21–135 °C and its encapsulated water temperature between 21–74 °C are demonstrated. The temperature regulation modulates the reaction kinetics in our graphene liquid marble, achieving a 12‐fold superior reaction rate constant for methylene blue degradation than at room temperature.     

A Remarkably Simple Class of Imidazolium‐Based Lipids and Their Biological Properties

A series of imidazolium salts bearing two alkyl chains in the backbone of the imidazolium core were synthesized, resembling the structure of lipids. Their antibacterial activity and cytotoxicity were evaluated using Gram‐positive and Gram‐negative bacteria and eukaryotic cell lines including tumor cells. It is shown that the length of alkyl chains in the backbone is vital for the antibiofilm activities of these lipid‐mimicking components. In addition to their biological activity, their surface activity and their membrane interactions are shown by film balance and quartz crystal microbalance (QCM) measurements. The structure–activity relationship indicates that the distinctive chemical structure contributes considerably to the biological activities of this novel class of lipids.