Fluorescence imaging characterisation of silicates

目标：这个多学科的项目是研究使用荧光恢复后光漂白（FRAP）显微镜和相关技术，以抑制纳米结构在硅酸盐液体中的扩散，这会影响这些液体在许多应用中的功效，包括多孔二氧化硅的制造。硅酸盐生产条件，控制这些液体中的胶体物种的大小和数量是知之甚少，主要是因为缺乏技术，以适当的处理所产生的silica.Background：虽然FRAP更通常用于生物系统的研究，可行性评估PQ公司几年前建议FRAP提供了一个有前途的方法，以更好地了解硅酸盐liquors。该项目的成功结果将提供一个比较硅酸盐的品质因数，这将大大提高对硅酸盐制造、结构和性能之间关系的理解。该项目建立在PQ和Strathclyde' Photophysics Group之间的长期合作基础上，该合作导致了硅酸盐纳米颗粒计量的新方法[1，2]。FRAP的工作原理需要一个微观区域的光漂白和记录的瞬态荧光强度恢复作为荧光物种的扩散重新进入研究中的区域的结果。目前，合作公司内部没有FRAP能力，但通过本项目，将在Strathclyde使用PQ提供的样品组装、开发和测试FRAP系统。Photophysics Group拥有光学设计、荧光和数据分析方面的专业知识，可用于构建和组装该仪器。集团还拥有广泛的配套仪器，以比较结果并优化FRAP性能。一旦开发和证明，该仪器可在PQ现场使用。作为该项目的一部分，学生将获得在英国PQ工作的宝贵工业经验，这些经验对于优化仪器性能至关重要。该项目的目的将通过完成几个关键目标（项目交付成果）来实现：1. FRAP显微镜系统的组装包括激光激发、显微镜组装、光学耦合、同步电子设备、光子检测和相关的图像分析软件。2.在酸性和碱性pH范围内评估FRAP的最佳荧光染料。3. FRAP系统在表征良好的标准硅酸盐溶胶上的测试和校准，包括与其他方法的比较，如光散射、荧光各向异性和荧光相关光谱。4.模拟硅酸盐颗粒扩散和FRAP和其他互补技术（分子动力学，激发态动力学，实验设计）检测到的观测值。确定最佳拟合模型和优化实验程序。5.硅酸盐表征以及来自改进的FRAP技术的数据与可能影响硅酸盐中存在的胶体物质的类型、数量和尺寸的工艺变量（例如Fe、Al、Ca、Mg的存在）的关联。PQ将提供已系统性改变生产条件的硅酸盐样品。6.研究样品的稳定性和老化（所有硅酸盐都是亚稳的）。7.使用FRAP技术进一步提高对硅酸盐生产、结构以及两者如何影响产品功效的理解。

The Aim: This multidisciplinary project is to investigate the use of fluorescence recovery after photobleaching (FRAP) microscopy and related techniques to characterise the diffusion of nm structures in silicate liquors, which influences the efficacy of these liquors in many applications including the manufacture of porous silicas. The silicate manufacturing conditions that control the size and number of colloidal species in these liquors is poorly understood, largely because of a lack of techniques to properly characterise the resulting silicates.Background: Although FRAP is more usually used for the study of biological systems, a feasibility assessment by PQ Corporation some years ago suggested FRAP offers a promising approach to better understanding silicate liquors. A successful outcome of the project would deliver a figure of merit with which to compare silicates that would significantly improve understanding of the relationships between silicate manufacture, structure and performance. The project builds on a long-standing collaboration between PQ and Strathclyde' Photophysics Group which led, amongst other outcomes, to a new method of silicate nanoparticle metrology [1,2]. The operating principle of FRAP requires photobleaching of a microscopic area and recording the transient fluorescence intensity recovery as a consequence of the diffusion of fluorescent species re-entering the area under study. At present there is no FRAP capability in-house at the collaborating company but, through this project, a FRAP system will be assembled, developed and tested at Strathclyde using samples that PQ will provide. The Photophysics Group has the optical design, fluorescence and data analysis expertise required to construct and characterise the instrument. The Group also possesses an expansive range of complementary instrumentation to compare results and optimise the FRAP performance. The instrument can be replicated for on-site use at PQ once developed and proven. The student will gain valuable industrial experience working at PQ in the UK as part of the project, experience that will be essential in optimising instrument performance. The aim of the project will be achieved by completing several key objectives (project deliverables):1. The assembly of a FRAP microscopy system to include laser excitation, microscope assembly, optical couplings, synchronisation electronics, photon detection and associated image analysis software. 2. Assessment of the optimum fluorescence dyes for FRAP over a range of acidic and alkaline pH.3. Testing and calibration of the FRAP system on well-characterised and standard silicate sols including comparison with other methods such as light scattering, fluorescence anisotropy and fluorescence correlation spectroscopy.4. Modelling the silicate particles diffusion and the observables detected by FRAP and other complementary techniques used (molecular dynamics, excited-state kinetics, experiment design). Determining the best-fit models and optimisation of the experimental procedure. 5. Silicate characterisation and correlating data from the improved FRAP technique with process variables (e.g. presence of Fe, Al, Ca, Mg) that may influence the type, number and size of colloidal species present in the silicate. PQ will provide silicate samples where manufacturing conditions have been altered in a systematic way. 6. Studies on samples stability and ageing (all the silicates will be metastable). 7. Using the FRAP technique to further improve understanding of the manufacture of silicates, their structure and how both of these influence product efficacy.