Development of Magnetic Sensors for MRI Cancer Imaging

描述(由申请人提供)：需要在细胞水平上了解癌症生物学，需要以高通量并且最好是同时对信使核糖核酸和蛋白质进行全面的询问。拟议研究的总体目标是扩大申请人的初步实验，以进一步开发、验证和优化能够感知不同类型分子目标的磁性纳米传感器(磁弛豫开关，MRS)。在初步的实验中，我们已经证明，当单分散的磁性纳米粒子自组装成低聚纳米组装时，核磁共振技术可以检测到的周围水的自旋-自旋弛豫时间(T2)相应地减少。这一基本观察使我们能够测量DNA-DNA、蛋白质-蛋白质、小分子蛋白质相互作用以及酶活性(NAT Biotech 2002；20,816-820)。磁弛豫开关(MRS)技术极其灵敏，可以用台式探测器检测飞摩尔水平的目标分子，并通过高分辨率磁共振成像检测目标分子水平。该分析是在溶液中进行的，不需要分离或纯化样品。在拟议的研究中，申请人将追求使用端粒酶作为癌症相关靶点的三个特定目标：(1)设计和优化独立识别端粒酶-mRNA、-蛋白质和酶活性的MRS探针；(2)开发和优化同时筛选端粒酶-mRNA、-蛋白质和-活性的磁共振技术；以及(3)开发和优化端粒酶MRS探针的内化方案，使其能够检测完整细胞内的靶点。利用发展起来的MRS技术，可以在细胞裂解产物和组织提取液中检测到端粒酶mRNA、端粒酶蛋白和端粒酶活性，而不需要事先进行纯化或扩增。所开发技术的主要生物技术和医学应用在于1)开发同时询问RNA和蛋白质的技术，2)高通量溶液相阵列的开发，以及3)通过磁共振成像成像分子相互作用的能力。拟议的研究将在多学科环境中进行，综合培训和研究计划将使候选人能够确立自己作为独立癌症研究人员的地位。

DESCRIPTION (provided by applicant): The need to understand cancer biology at a cellular level requires a comprehensive interrogation of mRNA and proteins at high throughput and preferably simultaneously. The overall goal of the proposed research is to expand preliminary experiments by the applicant to further develop, validate and optimize magnetic nanosensors (magnetic relaxation switches, MRS) capable of sensing different types of molecular targets. In preliminary experiments we have shown that when monodisperse magnetic nanoparticles self-assemble into oligomeric nanoassemblies, there is a corresponding decrease in the spin-spin relaxation times (T2) of surrounding water detectable by NMR techniques. This fundamental observation has allowed us to measure DNA-DNA, protein-protein, small molecule protein interactions as well as enzyme activities (Nat Biotech 2002;20, 816-820). The magnetic relaxation switch (MRS) technique is exceedingly sensitive, allowing the detection of target molecules at femtomole levels with bench-top detectors and attomole levels by high-resolution MR imaging. The assay is performed in solution and does not require isolation or purification of the sample. In the proposed research the applicant will pursue three specific aims using telomerase as a cancer related target: (1) design and optimize MRS probes that independently recognize telomerase-mRNA, -protein and enzyme activity; (2) develop and optimize magnetic resonance techniques for simultaneous screening of telomerase-mRNA, -protein and -activity; and (3) develop and optimize internalization protocols for telomerase MRS probes that would allow detection of a target inside intact cells. It is hypothesized that telomerase mRNA, telomerase protein and telomerase activity can be detected in cell lysates and tissue extracts without prior purification or amplification using the developed MRS technique. Major biotechnical and medical applications of the developed technique lie in 1) the development of techniques to simultaneously interrogate RNA and proteins, 2) the development of high-throughput solution phase arrays, and 3) the ability to image molecular interactions by magnetic resonance imaging. The proposed research will be conducted in a multidisciplinary environment and the integrated training and research program will enable the candidate to establish himself as an independent cancer researcher.