Intracellular Wireless Analysis of Single Cells by Bipolar Electrochemiluminescence Confined in a Nanopipette

The inside walls of a nanopipette tip are decorated by a Pt deposit that is used as an open bipolar electrochemiluminescence (ECL) device to achieve intracellular wireless electroanalysis. The synergetic actions of nanopipette and of bipolar ECL lead to the spatial confinement of the voltage drop at the level of the Pt deposit, which generates ECL emission from luminol. The porous structure of Pt deposit permits the electrochemical transport of intracellular molecules into the nanopipette that is coupled with enzymatic reactions. Thus, the intracellular concentrations of hydrogen peroxide or glucose are measured in vivo as well as the intracellular sphingomyelinase activity. In comparison with the classic bipolar ECL, the remarkably low potential applied in our approach is restricted inside the nanopipette and it minimizes the potential bias of the voltage on the cellular activity. Accordingly, this wireless ECL approach provides a new direction for analysis of single living cells.     

Label-Free Electrochemiluminescence Imaging of Single-Cell Adhesions by Using Bipolar Nanoelectrode Array

A label-free and fast approach for positive electrochemiluminescence (ECL) imaging of single cells by bipolar nanoelectrode array is proposed. The reduction of oxygen at a platinized gold nanoelectrode array in a closed bipolar electrochemical system is coupled with an oxidative ECL process at the anodic side. For elevating the ECL imaging contrast of single cells, a driving voltage of −2.0 V is applied to in situ generate oxygen confined beneath cells that is subsequently used for ECL imaging at 1.1 V. High oxygen concentration in the confined space resulting from steric hindrance generates prominent oxygen reduction current at the cathodic side and higher ECL intensity at the anodic side, allowing positive ECL imaging of the cells adhesion region with excellent contrast. Cell morphology and adhesion strength can be successfully imaged with high image acquisition rate. This approach opens a new avenue for label-free imaging of single cells.     

双极纳米电极阵列实现单个铂纳米颗粒上氢气析出反应的电致化学发光成像

本文制备了嵌于多孔阳极氧化铝（AAO）膜中直径为200 nm,间距为450 nm的高密度（5.7 × 10⁸ cm^-2）的金纳米电极阵列,纳米电极分布规则,尺寸高度均一。我们将该金纳米电极阵列作为双极电极阵列,可将电极一侧的电化学法拉第信号在另一侧电极上转化成电致化学发光（ECL）信号,从而实现对单个铂纳米颗粒上氢气析出反应（HER）进行亚微米空间分辨率的电化学成像。本文介绍的方法为高空间分辨率成像电催化材料、能源材料以及细胞过程的局部电化学活性提供了一个良好的平台。     

多孔硅表面钝化对其发光性能的影响

报道多孔硅（PS）的表面钝化对其光致发光（PL）和电致发光（EL）的影响。PL和EL谱表明,经钝化处理的PS的PL和EL强度明显增强,且发光峰位较大蓝移;存放实验表明,经钝化处理的PS的PL和EL发光强度和发光峰位具有较好的稳定性;I～V曲线显示,经钝化处理的PS发光器件具有较低的启动电压。这些结果表明：用钝化处理的方法是提高PS的PL和EL强度和稳定性及改善其器件性能的有效途径。     

Image‐Contrast Technology Based on the Electrochemiluminescence of Porous Silicon and Its Application in Fingerprint Visualization

The electrochemiluminescence (ECL) of porous silicon (pSi) has attracted great interest for its potential application in display technology and chemical sensors. In this study, we found that pSi with a different surface chemistry displayed an apparently different dynamic ECL process. An image‐contrast technology was established on the basis of the intrinsic mechanism of the ECL dynamic process. As a proof of principle, the visualization of latent fingerprints (LFPs) and in situ detection of TNT in fingerprints was demonstrated by using the ECL‐based image‐contrast technology.     

nc-Si:H/c-Si硅异质结太阳电池中本征硅薄膜钝化层的优化

采用射频等离子体增强化学气相沉积(RF-PECVD)法在低温、低功率的条件下制备了一系列本征硅薄膜, 研究了硅烷浓度(C_S)对薄膜微结构、光电特性及表面钝化性能的影响. 将本征硅薄膜作为钝化层应用到氢化纳米晶硅/晶硅(nc-Si:H/c-Si)硅异质结(SHJ)太阳电池中, 研究了硅烷浓度和薄膜厚度对电池性能的影响. 实验发现: 随着硅烷浓度的降低, 本征硅薄膜的晶化率、氢含量、结构因子、光学带隙和光敏性等都在过渡区急剧变化; 本征硅薄膜的钝化性能由薄膜的氢含量及氢的成键方式决定. 靠近过渡区的薄膜具有较好的致密性和光敏性, 氢含量最高, 带隙态密度低, 且主要以SiH 形式成键, 对硅片表现出优异的钝化性能, 使电池的开路电压大幅提高. 但是, 当薄膜的厚度过小时, 会严重影响其钝化质量. 本实验中, 沉积本征硅薄膜的最优硅烷浓度为6% (摩尔分数), 且当薄膜厚度为~8 nm时, 所制备电池的性能最好. 实验最终获得了开路电压为672 mV, 短路电流密度为35.1 mA·cm^-2, 填充因子为0.73, 效率为17.3%的nc-Si:H/c-Si SHJ太阳电池     

电化学发光成像技术及其在阵列传感分析和潜在指纹成像分析中的应用

电化学发光成像技术作为一种新的生化分析手段,具有设备简单、反应可控、多信息化和可视化等优点. 目前,该技术已被用于便携式、微型化、高通量的电化学发光传感器中,并取得了一系列创新性成果. 本文结合作者课题组的研究进展,简要介绍了电化学发光成像技术在阵列传感分析和潜在指纹检测中的应用,并尝试着展望了今后的发展趋势.     

Facile Tuning of Luminescent Platinum(II) Schiff Base Complexes from Yellow to Near‐Infrared: Photophysics,Electrochemistry, Electrochemiluminescence and Theoretical Calculations

The photophysical and related properties of platinum(II) Schiff base complexes can be finely and predictably tuned over a wide range of wavelengths by small and easily implemented changes to ligand structure. A series of such complexes, differing only in the number and positioning of methoxy substituents on the phenoxy ring, were synthesised and their photophysical, electrochemical and electrochemiluminescent (ECL) properties investigated. Theoretical calculations were performed in order to gain further insight into the relationship between structure and properties in these materials. By positioning methoxy groups para and/or ortho to either the imine or the oxygen group on the ligand, electron density could be directed selectively toward the LUMO or HOMO as required. This allowed the emission colour (both photoluminescent and electrochemiluminescent) to be tuned over a wide range between 587 and 739 nm. The variation in orbital energies was also manifested in the positions of the absorption bands and the redox properties of the complexes, as well as in the NMR shifts for the uncoordinated ligands. All reported complexes displayed intense electrochemiluminescence (ECL), which could be initiated either by annihilation or co‐reactant pathways. The relationship between the electrochemical and photophysical properties and the efficiency of the ECL is discussed. For two of the complexes solid‐state ECL could be generated from electrodeposited layers of the complex.     

以模型认知素养为导向的电化学模拟题的命制*——以双极膜的应用为例

以双极膜发展进程为线索,以海水淡化、钠碱循环法脱除烟气中的SO₂等现实发展中真实问题为载体,结合中学生的认知能力水平,构建了电化学双极膜认识模型;命制了双极膜及其应用的电化学模拟题,以此测查学生模型认知素养的水平等级。阐述命题策略及过程,提供以模型认知素养为导向的试题命制思路;从模型建构的角度对2020年高考新课标Ⅰ卷第12题进行了评析。     

基于花状铂纳米颗粒构建的电致化学发光免疫传感器用于检测载脂蛋白A1

采用一锅合成法制备了新型的具有大比表面积的花状铂纳米颗粒（PtNFs）,并构建了一个高灵敏电致化学发光（ECL）免疫传感器用于检测载脂蛋白A1（Apo-A1）. 该PtNFs用于吸附二抗（anti-Apo-A1）,并用葡糖糖氧化酶（GOD）封闭其表面的非特异性位点,最终制备了PtNFs@anti-Apo-A1@GOD信号探针. 当Apo-A1存在时,通过夹心免疫反应将制备的信号探针捕获于电极表面,并将所制得的电极置于含有葡萄糖的过硫酸根底液中检测. GOD催化葡萄糖产生H₂O₂,H₂O₂在PtNFs的催化下分解并在电极表面原位产生O₂,所产生的O₂能够催化过硫酸根-氧气体系的电致化学发光反应,放大发光信号,提高检测灵敏度. 该传感器在0.1ng•mL^-1 ~ 100 ng•mL^-1范围内对Apo-A1有良好的线性响应,检测下限达到0.03ng•mL^-1,有望应用于临床分析诊断.     

Bipolar Verdazyl Radicals for Symmetrical Batteries: Properties and Stability in All States of Charge

Redox flow batteries based on organic electrolytes are promising energy storage devices, but stable long-term cycling is often difficult to achieve. Bipolar organic charge-storage materials allow the construction of symmetrical flow batteries (i. e., with identical electrolyte composition on both sides), which is a strategy to mitigate crossover-induced degradation. One such class of bipolar compounds are verdazyl radicals, but little is known on their stability/reactivity either as the neutral radical, or in the charged states. Here, we study the chemical properties of a Kuhn-type verdazyl radical ( 1 ) and the oxidized/reduced form ( 1^+/− ). Chemical synthesis of the three redox-states provides spectroscopic characterization data, which are used as reference for evaluating the composition of the electrolyte solutions of an H-cell battery during/after cycling. Our data suggest that, rather than the charged states, the decomposition of the parent verdazyl radical is responsible for capacity fade. Kinetic experiments and DFT calculations provide insight in the decomposition mechanism, which is shown to occur by bimolecular disproportionation to form two closed-shell products (leuco-verdazyl 1H and triazole derivative 2 ).     

硅表面嫁接有机单分子膜的研究近况

由于在微电子、化学 /生物化学传感器、纳米技术及太阳能等领域具有潜在的应用价值 ,通过 Si— C键在硅表面上直接嫁接有机单分子膜 ,已成为近几年新开展的研究热点 .对这一研究领域进行了概要综述     

On the Origin of Damped Electrochemical Oscillations at Silicon Anodes (Revisited)

Electrochemical oscillations accompanying the formation of anodic silica have been shown in the past to be correlated with rather abrupt changes in the mechanical stress state of the silica film, commonly associated with some kind of fracture or porosification of the oxide. To advance the understanding on the origin of such oscillations in fluoride‐free electrolytes, we have revisited a seminal experiment reported by Lehmann almost two decades ago. We thereby demonstrate that the oscillations are not stress‐induced, and do not originate from a morphological transformation of the oxide in the course of anodisation. Alternatively, the mechanical features accompanying the oscillations can be explained by a partial relaxation of the field‐induced electrostrictive stress. Furthermore, our observations suggest that the oscillation mechanism more likely results from a periodic depolarisation of the anodic silica.     

Coupling a Wireless Bipolar Ultramicroelectrode with Nano-electrospray Ionization Mass Spectrometry: Insights into the Ultrafast Initial Step of Electrochemical Reactions

We report a new mass spectrometric method for detecting electrogenerated intermediates. This approach is based on simultaneous activation of electrospray ionization and redox reaction on a wireless bipolar ultramicroelectrode, which is fabricated in the tip of a quartz nanopipette. The hollow structure of the ultramicroelectrode permits rapid transferring the transient species from electrode–electrolyte interfaces into the gas phase for mass spectrometric identification on the time scale of microseconds. The long-sought fleeting intermediates including TPrA^.+, whose lifetime in solution is only 200 μs, and catecholamine o-semiquinone radicals, the second-order rate constant of which is typically 10⁹ m ⁻¹ s⁻¹, were successfully identified, helping clarify the previously hidden reaction pathways. Accordingly, our method may have wide applicability in exploring the dynamics of many electrochemical reactions, especially their ultrafast initial steps.     

界面钝化策略:提高钙钛矿太阳能电池的稳定性

近年来,新兴起的有机无机杂化钙钛矿太阳能电池突飞猛进,在短短十年里其光电转化效率从3.8%迅速发展到目前25.2%的认证效率,被视为最具有应用潜力的新型高效率太阳能电池之一。虽然钙钛矿太阳能电池具有很高的光电转换效率已与多晶硅薄膜电池相媲美,但是电池的长期稳定性仍是阻碍其商业化的一大挑战。钙钛矿表面和晶界存在大量的缺陷,界面钝化来提高钙钛矿太阳能电池的稳定性是非常重要且有效的策略。二维钙钛矿材料是有机胺层与无机层交替的层状钙钛矿,具有体积较大的有机铵阳离子,与传统的三维钙钛矿材料相比对于环境的稳定性较好,并且结构灵活可调,在三维钙钛矿表面修饰二维钙钛矿层钝化缺陷,在提高钙钛矿太阳能电池效率的同时又保证了稳定性,另外,合适的钝化剂分子也能够非常有效地钝化缺陷。本文总结了钙钛矿太阳能电池的不稳定因素,归纳了钙钛矿太阳能电池界面钝化方面的研究进展,指出了二维钙钛矿材料发展的巨大潜力以及寻找合适钝化剂分子的原则,期望能够为获得高性能的钙钛矿太阳能电池进而实现商业化提供有益的指导。     

Coupling a Wireless Bipolar Ultramicroelectrode with Nano‐electrospray Ionization Mass Spectrometry: Insights into the Ultrafast Initial Step of Electrochemical Reactions

We report a new mass spectrometric method for detecting electrogenerated intermediates. This approach is based on simultaneous activation of electrospray ionization and redox reaction on a wireless bipolar ultramicroelectrode, which is fabricated in the tip of a quartz nanopipette. The hollow structure of the ultramicroelectrode permits rapid transferring the transient species from electrode–electrolyte interfaces into the gas phase for mass spectrometric identification on the time scale of microseconds. The long‐sought fleeting intermediates including TPrA^.+, whose lifetime in solution is only 200 μs, and catecholamine o‐semiquinone radicals, the second‐order rate constant of which is typically 10⁹ m ^?1 s^?1, were successfully identified, helping clarify the previously hidden reaction pathways. Accordingly, our method may have wide applicability in exploring the dynamics of many electrochemical reactions, especially their ultrafast initial steps.