Two-photon impedance, potential and fluorescence imaging - a feasibility study

双光子阻抗、电势和荧光成像——可行性研究

• 批准号: EP/D057574/1
• 负责人: Steffi Krause
• 金额: $ 7.95万
• 依托单位: Queen Mary University of London
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2006
• 资助国家: 英国
• 起止时间: 2006 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FD057574%2F1
• 关键词: Two; photon; impedance; potential; fluorescence

We will investigate the feasibility of using a multi-photon effect to achieve 200 nm resolution for two electrochemical laser scanning techniques, Scanning Photo-induced Impedance Microscopy (SPIM) and Light-Addressable Potentiometric Sensors (LAPS). Both techniques are based on photocurrent measurements at electrolyte/insulator/semiconductor field-effect structures. The non-linear absorption of light in two-photon experiments will be used to confine the generation of charge carriers to the semiconductor/insulator interface. This will facilitate the use of standard silicon wafers for high resolution LAPS and SPIM eliminating the problems encountered using alternative semiconductor substrates such as GaAs, amorphous silicon and Silicon on Sapphire (SOS) and also reduce the cost of the substrate material. A resolution of 200 nm would mean an improvement by a factor of 80 compared to previous results. This is a very ambitious goal. Hence we are proposing to carry out the current feasibility study before venturing into new applications for the high-resolution imaging techniques.SPIM is capable of measuring the local electrical impedance of materials and biological samples. This has potential applications in the characterisation of polymeric and ceramic materials with complicated three-dimensional architectures and impedance based processes in biological cells such as the opening and closing of ion channels. LAPS can be used to measure charge based events such as changes in local electrical potentials and ionic concentrations in materials and biological cells. Subcellular resolution would allow imaging of metabolic events and ion channel activity in the attachment area of a single cell and detailed investigation of the interaction of cells with materials surfaces. Both techniques also have potential application in array technology as they allow measurement of local impedance, potential or concentration changes without the use of labels.In addition we will endeavour to integrate these two electrochemical characterisation techniques with two-photon fluorescence microscopy. All three techniques integrated in the instrument require a tightly focused laser beam to excite either a photocurrent or fluorescence. To excite the electrical signal and to produce the optical image the laser beam will be focused through the same lenses, i.e. electrical and optical signal will truly originate from the same microenvironment. This will create a new tool for the characterisation and screening of new materials and biological systems. The combined techniques will not only provide information about the local electrical properties of materials, but the 3-dimensional optical image produced by two-photon fluorescence microscopy will allow direct correlation of the microstructure with the 2-dimensional electrical data thus providing the prerequisites for accurate modelling. Information about local microscopic properties such as pore sizes, voids, pore connectivity and the presence and geometrical extension of phases with different charge carrier mobilities or dielectric constants in the third dimension obtained from microscopic data can be used to calculate current paths and make it easier to extract quantitative data from SPIM.

我们将研究使用多光子效应实现200 nm分辨率的两种电化学激光扫描技术，扫描光诱导阻抗显微镜（SPIM）和光寻址电位传感器（LAPS）的可行性。这两种技术都是基于在电解质/绝缘体/半导体场效应结构的光电流测量。在双光子实验中，光的非线性吸收将被用于将载流子的产生限制在半导体/绝缘体界面。这将有助于使用标准硅晶片进行高分辨率LAPS和SPIM，消除使用诸如GaAs、非晶硅和蓝宝石上硅（SOS）的替代半导体衬底所遇到的问题，并且还降低了衬底材料的成本。200 nm的分辨率意味着与以前的结果相比提高了80倍。这是一个非常雄心勃勃的目标。因此，我们建议在冒险进入高分辨率成像技术的新应用之前进行当前的可行性研究。SPIM能够测量材料和生物样品的局部电阻抗。这在表征具有复杂三维结构和生物细胞中基于阻抗的过程（例如离子通道的打开和关闭）的聚合物和陶瓷材料中具有潜在的应用。LAPS可用于测量基于电荷的事件，例如材料和生物细胞中局部电势和离子浓度的变化。亚细胞分辨率将允许在单个细胞的附着区域中对代谢事件和离子通道活性进行成像，并详细研究细胞与材料表面的相互作用。这两种技术也有潜在的应用在阵列技术，因为它们允许测量局部阻抗，电位或浓度的变化，而不使用labels. Also，我们将努力整合这两个电化学表征技术与双光子荧光显微镜。集成在仪器中的所有三种技术都需要一个紧密聚焦的激光束来激发光电流或荧光。为了激发电信号并产生光学图像，激光束将通过相同的透镜聚焦，即电信号和光信号将真正源自相同的微环境。这将为新材料和生物系统的表征和筛选创造一个新的工具。相结合的技术将不仅提供有关材料的局部电性能的信息，但由双光子荧光显微镜产生的三维光学图像将允许直接相关的微观结构与二维电气数据，从而提供了准确建模的先决条件。有关局部微观性质的信息，如孔径，空隙，孔连通性和存在和几何扩展的阶段，具有不同的电荷载流子迁移率或介电常数在第三维从微观数据中获得的，可以用来计算电流路径，并使其更容易从SPIM提取定量数据。