Spin Probes in Semipermeable Nanospheres: EPR spectroscopy & imaging of tumor pH

半透性纳米球中的自旋探针：EPR 光谱

• 批准号: 7554633
• 负责人: Valery V Khramtsov
• 金额: $ 20.25万
• 依托单位: OHIO STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-01-09 至 2010-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7554633
• 关键词: Acidosis; Acids; Amines; Animals; Ascorbic Acid; Biochemical; Biochemical Process; Biochemistry; Biological; Buffers; Characteristics; Chemicals; Chloride Ion; Chlorides; Data; Detection; Development; Electron Spin Resonance Spectroscopy; Ensure; Enzymes; Female; Fluorine; Future; Goals; Granulocyte-Macrophage Colony-Stimulating Factor; Human; Image; Intercellular Fluid; Ions; Lactic acid; Life; Lipids; Liposomes; Magnetic Resonance Imaging; Mammary Neoplasms; Measurement; Medicine; Membrane; Methods; Modeling; Monitor; Mus; Nanosphere; Neoplasm Metastasis; Normal tissue morphology; Nylons; Organism; Oxygen; Penetration; Perfusion; Permeability; Phase; Phospholipids; Phosphorus; Play; Preparation; Procedures; Prognostic Factor; Reaction Time; Reducing Agents; Reporting; Role; Solid Neoplasm; Solutions; Specificity; Spectrum Analysis; Techniques; Therapeutic; Time; Tissues; UV induced; Variant; Vesicle; Water; angiogenesis; antitumor drug; aqueous; base; bioimaging; biological systems; capsule; crosslink; design; extracellular; gramicidin A; in vivo; inorganic phosphate; insight; interest; interfacial; monomer; nanosensors; nanosized; nitroxyl; particle; polymerization; research study; sensor; success; tumor; tumor growth; tumor initiation; tumor progression

DESCRIPTION (provided by applicant): The overall goal of this project is to develop new functional EPR probes of enhanced stability for in vivo EPR spectroscopy and imaging of pH, one of the most important parameters in the biochemistry of living organisms. pH-sensitive nitroxyl radicals have been previously developed by the P.I. and colleagues but often suffer insufficient stability in living tissues. In this project two different strategies will be used to develop paramagnetic probes with stability in vivo based on the original idea of constructing nano-Sized Particles with the Incorporated Nitroxides, or nanoSPINs. The semipermeable membrane of the nanoSPINs will differentiate sensing nitroxides from biological reductants while allowing free penetration of the analyze, H+. This will fill a niche between fluorescent pH probes, which have provided advances in applications for cellular and subcellular detection, and NMR/MRI, which have provided applications in living animals and humans, but these current techniques often suffer from the lack of sensitivity (1000 fold or lower than EPR) and specificity. The specific aims are: (SA1) To develop effective approaches for the design of pH-sensitive nanoSPINs. Two alternative strategies for the incorporation of the nitroxides into semipermeable nanospheres will be used, namely incorporation into phospholipids liposomes and polyamide capsules. (SA2) To define spectroscopic and physicochemical characteristics of pH-sensitive nanoSPINs. Quantitative characterization of the obtained nanoSPIN is absolutely crucial both for the optimization of the preparation procedures and for efficiency of their further applications. (SA3) To apply in vivo EPR measurements of pHe in PyMT tumor-bearing mice using developed nanoSPINs. The measurement of the extracellular pHe in the PyMT mammary tumors in living mice using developed pH- sensitive nanoSPINs will provide new insights into related biochemical processes, including better understanding of the observed anti-tumor activity of Granulocyte Macrophage Colony-Stimulating Factor (GM-CSF), a therapeutic approach which is currently of much interest. The results may provide an opportunity for the design of other corresponding therapeutic approaches. In summary, the success of this project may have a significant impact on the future of functional in vivo EPR spectroscopy and bioimaging applications to medicine. This project will develop pH-sensitive paramagnetic probes of enhanced stability based on encapsulation of the nitroxides into semipermeable nanospheres. These probes, termed nanoSPINs, will allow in vivo EPR spectroscopy and imaging of pH. The experiments using pH-sensitive nanoSPINs in PyMT mammary tumors in living mice are planned to contribute to the understanding of the mechanisms of extracellular acidosis in solid tumors and to use extracellular pH to monitor tumor progression and thus evaluate the efficacy of anti-tumor drugs, and provide opportunities for designing corresponding therapeutic approaches.

描述（由申请人提供）：该项目的总体目标是开发新的功能性 EPR 探针，增强稳定性，用于体内 EPR 光谱和 pH 成像，pH 是活体生物化学中最重要的参数之一。 pH 敏感的硝酰基自由基此前已由 P.I. 开发。和同事，但经常遭受活体组织稳定性不足的困扰。在该项目中，基于用掺入的氮氧化物（nanoSPIN）构建纳米粒子的最初想法，将使用两种不同的策略来开发体内稳定性的顺磁探针。 nanoSPIN 的半透膜将区分传感硝基氧和生物还原剂，同时允许分析物 H+ 自由渗透。这将填补荧光 pH 探针和 NMR/MRI 之间的空白。荧光 pH 探针在细胞和亚细胞检测的应用方面取得了进展，而 NMR/MRI 在活体动物和人类中提供了应用，但这些现有技术往往缺乏灵敏度（比 EPR 1000 倍或更低）和特异性。具体目标是： (SA1) 开发设计 pH 敏感的 nanoSPIN 的有效方法。将使用两种将硝基氧掺入半透性纳米球的替代策略，即掺入磷脂脂质体和聚酰胺胶囊。 (SA2) 定义 pH 敏感的 nanoSPIN 的光谱和物理化学特性。所获得的 nanoSPIN 的定量表征对于制备过程的优化及其进一步应用的效率绝对至关重要。 (SA3) 使用开发的 nanoSPIN 对 PyMT 荷瘤小鼠体内 pHe 进行体内 EPR 测量。使用开发的 pH 敏感 nanoSPIN 测量活体小鼠 PyMT 乳腺肿瘤中的细胞外 pHe 将为相关生化过程提供新的见解，包括更好地了解观察到的粒细胞巨噬细胞集落刺激因子 (GM-CSF) 的抗肿瘤活性，这是一种目前备受关注的治疗方法。该结果可能为其他相应治疗方法的设计提供机会。总之，该项目的成功可能会对功能性体内 EPR 光谱和生物成像在医学上的应用的未来产生重大影响。该项目将开发基于将硝基氧封装到半透性纳米球中的稳定性增强的 pH 敏感顺磁探针。这些探针被称为 nanoSPIN，可实现体内 EPR 光谱和 pH 成像。在活体小鼠PyMT乳腺肿瘤中使用pH敏感的nanoSPIN进行实验，计划有助于理解实体瘤中细胞外酸中毒的机制，并利用细胞外pH来监测肿瘤进展，从而评估抗肿瘤药物的疗效，并为设计相应的治疗方法提供机会。