Hybrid Nanogels as Biostable Non-Toxic Multifunctional Imaging Agentsfor MRI

项目概要：SCORE赠款将联合收割机结合PI的专业知识，在蛋白质封装在硅基 溶胶-凝胶基质和纳米粒子与他的工作与稳定的环状氮氧自由基和他的专业知识，在光谱 方法，并允许他开发和应用它来解决公共卫生的重要挑战。目标是 产生新型氮氧化物混合纳米凝胶，其将用作MRI诊断测试的无毒造影剂， 与肾源性系统性心脏病的发生有关的常用钆基造影剂（GBCA） 患者的纤维化我们的方法是创新的，因为我们利用溶胶-凝胶纳米颗粒基质来增强 以及增加它们在体内的稳定性和抑制它们的 生物还原这项研究将探索产生包埋的基于溶胶-凝胶的混合纳米颗粒的方法 氮氧自由基或氮氧自由基-蛋白质缀合物，导致改善的生物稳定性、亲水性和1H水弛豫率（r1）。在 与Krishna博士合作，该领域的领先专家，选择氮氧混合纳米凝胶（NHN）表现出改善 将使用体外MRI表征和优化活性。这些研究将确定有前途的NHN， 进一步扩展到NCI的动物研究。具体目标1。基于溶胶-凝胶的纳米颗粒（纳米凝胶）的制造：我们 将使用原硅酸四甲酯和/或原硅酸四乙酯和它们的衍生物用于溶胶-凝胶合成， 纳米凝胶尺寸和溶解度。我们将探索一种新兴的仿生方法来制造混合纳米凝胶。 具体目标2。氮氧化物和氮氧化物-蛋白质缀合物在纳米凝胶内的固定化。选择 将测试氮氧化物，包括TEMPOL、3-CP、TEMPO-Lomustine、螺环己基氮氧化物1-OH和四乙基 氮氧自由基2-OH空间保护的氮氧自由基，不易受生物还原影响，以及氮氧自由基蛋白质 共轭具体目标3。结构和功能表征的捕获氮氧自由基：我们将研究 改性纳米凝胶的粒径分布、溶解性、聚集性和负载能力以及它们的 泄漏/泄漏。UV/维斯光谱、EPR光谱和生物化学测定将用于表征 嵌入的氮氧化物，包括其还原率的测定。具体目标4。氮氧化合物的测试 包埋的混合纳米凝胶作为体外和小鼠模型中MRI的造影剂。优化NHN以获得最高 体外弛豫率（> 5 mM-1 S-1），随后进行体内药代动力学和毒性表征。这笔赠款将用于 通过加速数据收集和提高出版生产力，加强PI的研究计划， PI将发展他的研究竞争力，并过渡到非SCORE支持。这项研究的结果将是 用于在项目的第三年申请NIH RO 1资助。皇后学院的本科生和研究生， 其中许多人来自生物医学研究界代表性不足的人群，可以参加 research.学生将接触到生物纳米技术的新兴领域的方法和仪器， 纳米医学，从而提高他们的生物医学科学技能。这项研究将克服公共卫生挑战 通过开发无毒的MRI造影剂来替代与肾源性系统性纤维化有关的GBCA。

PROJECT SUMMARY: The SCORE grant will combine the PI expertise in protein encapsulation within silica based sol-gel matrices and nanoparticles with his work with stable cyclic nitroxide radicals and his expertise in spectroscopic methods and allow him to develop and apply it to address important challenges in public health. The objective is to generate novel nitroxides hybrid nanogels that will serve as non-toxic contrast agents for MRI diagnostic tests replacing the commonly used gadolinium-based contrast agents (GBCA) that are linked to the development of nephrogenic systemic fibrosis in patients. Our approach is innovative in that we utilize the sol-gel nanoparticle matrix to enhance the relaxivity of embedded nitroxides radicals as well as to increase their in vivo stability and inhibit their bioreduction. This research will explore methods for generation of sol-gel based hybrid nanoparticles with entrapped nitroxides or nitroxide-protein conjugates resulting in improved biostability, hydrophilicity and 1H water relaxivity (r1). In collaboration with Dr. Krishna, a leading expert in the field, select nitroxide hybrid nanogels (NHN) exhibiting improved activity will be characterized and optimized using in vitro MRI. These studies will identify promising NHN that will be further extended to animal studies at NCI. Specific Aim 1. Fabrication of Sol-gel based nanoparticles (nanogels): We will use tetramethylorthosilicate and/or tetraethylorthosilicate and their derivatives for sol-gel synthesis optimizing the nanogels size and solubility. We will explore an emerging biomimetic approach for the fabrication of hybrid nanogels. Specific Aim 2. Immobilization of nitroxides and nitroxide-protein conjugates within the nanogels. Selected nitroxides will be tested including TEMPOL, 3-CP, TEMPO-Lomustine, spirocyclohexyl nitroxide 1-OH and tetraethyl nitroxide 2-OH sterically protected nitroxides that are less susceptible to bio-reduction, as well as nitroxide-protein conjugates. Specific Aim 3. Structural and functional characterization of the entrapped nitroxides: We will study the size distribution, solubility, aggregation and loading capacity of the modified nanogel as well as rates of their release/leakage. UV/vis spectroscopy, EPR spectroscopy, and biochemical assays will be used to characterize the embedded nitroxides, including determination of their reduction rates. Specific Aim 4. Testing of the nitroxide entrapped hybrid nanogels as contrast agents for MRI in vitro and in mouse models. Optimize the NHN for highest relaxivity (>5mM-1S-1) in vitro followed by in vivo pharmacokinetic and toxicity characterization. This grant will serve to enhance the PI's research program, through acceleration of data collection and an increase in publication productivity, the PI will develop his research competitiveness and transition to non-SCORE support. The results of this research will be used to apply to an NIH RO1 grant by the third year of the project. Queens College undergraduate and graduate students, many of which are from populations under-represented in the biomedical research community, could participate in the research. Students will be exposed to methods and instrumentation of the emerging fields of bio-nanotechnology and nanomedicine, thereby enhancing their biomedical sciences skills. This research will overcome a public health challenge by developing non-toxic MRI contrast agents replacing GBCA that are linked to nephrogenic systemic fibrosis.