Towards Deep Tissue Imaging of Fluorescence Resonance Energy Transfer Parameters

0854249 Webb荧光共振能量转移（FRET）已被证明在研究化学物质转运到细胞中以及由于例如蛋白质错误折叠（其可能导致阿尔茨海默病）引起的疾病的根本原因方面具有巨大价值。已经测量了通过FRET转移的供体荧光的淬灭，并且分子内FRET参数（寿命和产率，以及在柔性接头的情况下，接头距离的平均值和方差）已经被广泛使用。然而，FRET成像已被限制在体外或表面显微镜，因为大量散射的有害影响。本项目的目标是证明一种方法，用于成像FRET参数在高散射介质中，从而提供了机会，在体内的深层组织FRET研究。新的工作计划如下：-发展的方法，以图像FRET参数与ODT：荧光共振能量转移光学扩散断层扫描（FRET-ODT）成像方法将被开发。这将涉及一个解决方案的分子内FRET参数与刚性和柔性连接器，被纳入作为未知来源的扩散方程表示供体荧光。将研究对参数空间（调制频率，源-检测器布置，FRET参数，信噪比）的灵敏度，并开发适合于在散射介质中使用FRET源的实验数据的软件。将受体动力学的优点也将进行研究。以类似的方式，分子间FRET源将在ODT框架中实现。FRET-ODT实验研究：将构建一个模型组织实验，以获得数据来评估将开发的FRET-ODT成像方法。允许不同程度的散射，不同的FRET化学浓度，不同的供体-受体的距离和距离分布，和多个调制频率，以及一个不均匀的背景的影响的影响的数据，将获得。作为体内FRET-ODT应用，将使用FRET模型研究用于靶向药物递送至癌细胞的小鼠模型，以及随后的药物进入和释放，所述FRET模型结合关于转运动力学的信息并且模拟药物递送过程。这项研究的信息将有助于开发有选择性地递送到癌细胞的靶向药物，从而防止通常在化疗期间发生的对健康细胞的损害（例如，白细胞减少症-白色血细胞缺乏，脱发-脱发，便秘和高血压）。这项工作将由部门内的低级别小组完成。普渡大学的化学教授

0854249WebbFluorescence resonance energy transfer (FRET) has proved to be of immense value in the study of chemical transport into cells and the underlying cause of disease due to, for example, protein misfolding (which may lead to Alzheimer's disease). The quenching of donor fluorescence by FRET transfer has been measured, and the intramolecular FRET parameters (lifetime and yield, and in the case of a flexible linker, the mean and variance of the linker distance) have been widely used. However, FRET imaging has been limited to in vitro or surface microscopy because of the deleterious effects of substantial scatter. The goal of this project is to demonstrate a method for imaging FRET parameters in highly scattering media, thereby providing the opportunity for deep tissue in vivo FRET studies. The new work planned is as follows:- Development on an Approach to Image FRET Parameters with ODT: A fluorescence resonance energy transfer optical diffusion tomography (FRET-ODT) imaging approach will be developed. This will involve a solution for the intramolecular FRET parameters with both rigid and flexible linkers that are incorporated as unknown sources in a diffusion equation representation for the donor fluorescence. The sensitivity to the parameter space (modulation frequencies, source-detector arrangement, FRET parameters, signal to noise ratio) will be studied and software suitable for use with experimental data for FRET sources in a scattering medium will be developed. The merits of incorporating acceptor kinetics will also be investigated. In a similar way, intermolecular FRET sources will be implemented in an ODT framework.- FRET-ODT Experimental Studies: A model tissue experiment will be constructed to obtain data to evaluate the FRET-ODT imaging approach to be developed. Data allowing the influence of varying degrees of scatter, varying FRET chemical concentration, varying donor-acceptor distance and distance distribution, and multiple modulation frequencies, as well as the effect of an inhomogeneous background, will be obtained. As an in vivo FRET-ODT application, a mouse model for targeted drug delivery to cancer cells, with the subsequent drug entry and release, will be studied using a FRET model that incorporates information about the transport kinetics and which emulates the drug delivery process. Information from this study will aid in the development of targeted drugs that are selectively delivered to cancer cells, thereby preventing damage to healthy cells that usually occurs during chemotherapy (for example, leucopenia - a deficiency in white blood cells, alopecia - hair loss, constipation, and hypertension). This work will be done with the Low group in the Dept. of Chemistry at Purdue.