Development of spin probes for cell-tagging and oximetry

描述（由申请人提供）：氧是生物系统中最重要的分子之一，因为它作为反应物或产物参与了大量的生物化学过程。该元素存在于大多数生物分子中，这些生物分子对活生物体至关重要，并且在细胞呼吸和活细胞线粒体中的电子传递链中起着至关重要的作用。由于氧气供应或利用的改变而可能发生的氧气水平的任何不平衡都可能影响代谢稳态并导致病理生理学。因此，一种评估和跟踪组织氧水平变化的方法对于我们理解发病机制和制定纠正失衡的有效策略的能力至关重要。这将需要能够以良好的空间和时间分辨率量化组织氧合水平的方法。理想情况下，这些测量应通过微创或非侵入性手段获得。因此，本提案的总体目标是开发可用于临床应用的电子顺磁共振（EPR）血氧测定的安全植入式氧传感探头（OxyChips）。探头将被设计为植入感兴趣的组织中，允许通过非侵入性方法重复测量相同部位的组织氧合。这类新的EPR探针将基于嵌入氧可渗透生物相容性基质聚二甲基硅氧烷（PDMS）中的氧敏颗粒探针。使用这种方法，将制造和表征各种形状、大小和尺寸的OxyChip植入物。还将测试穿刺针的耐用性，以确保其按预期运行。然后将在几种临床相关的人类疾病动物模型中进行生物相容性测试和探针适用性验证。提出了以下具体目标：1）颗粒EPR探针的封装和OxyChips的制造; 2）封装EPR颗粒的生物稳定性和生物相容性评价; 3）OxyChips的毒性、免疫反应和安全性评价;以及4）OxyChips在临床相关疾病动物模型中的体内植入和测试。从这些设备获得的信息将提供对各种代谢和疾病状态（例如癌症和外周血管疾病）的更好理解，并有助于做出有关治疗和疗法的有效临床决策。本提案的长期目标是开发用于临床电子顺磁共振（EPR）血氧测定的植入式氧传感探头。氧存在于对生物体至关重要的大多数生物分子中，并在正常和改变的生理学中的许多过程中发挥作用。一旦植入，新的探针将允许重复，无创测量组织中的氧浓度。该探针可用于跟踪肿瘤组织的生长和/或死亡、外周动脉疾病和肌肉萎缩的进展以及伤口愈合反应。

DESCRIPTION (provided by applicant): Oxygen is one of the most important molecules in biological systems since it is involved as either a reactant or a product in a vast number of biochemical processes. The element is found in most biomolecules that are essential to living organisms, and plays a crucial role in cellular respiration and the electron transport chain in the mitochondria of living cells. Any imbalance in oxygen levels, which can occur due to altered supply or utilization of oxygen, may affect metabolic homeostasis and lead to pathophysiology. Thus, a means by which to evaluate and track changes in tissue oxygen levels will be of paramount importance in our ability to understand the mechanisms of pathogenesis and to develop effective strategies to correct the imbalance. This would require methods capable of quantifying the levels of tissue oxygenation with good spatial and temporal resolution. Ideally, these measurements should be obtained through minimally invasive or noninvasive means. Thus, the overall objective of this proposal is to develop safe, implantable oxygen-sensing probes (OxyChips) for electron paramagnetic resonance (EPR) oximetry that can be used in clinical applications. The probes will be designed to be implanted in the tissue of interest, permitting repeated measurements of tissue oxygenation from the same site by noninvasive means. This new class of EPR probes will be based on oxygen-sensitive particulate probes embedded in an oxygen-permeable biocompatible substrate, polydimethylsiloxane (PDMS). Using this approach, OxyChip implants of various shapes, sizes, and dimensions will be fabricated and characterized. The robustness of the probes will also be tested to ensure that they will perform as expected. Biocompatibility testing and validation of the probe applicability will then be performed in several clinically-relevant animal models of human disease. The following specific aims are proposed: 1) Encapsulation of particulate EPR probes and fabrication of OxyChips; 2) Biostability and biocompatibility evaluation of encapsulated EPR particulates; 3) Toxicity, immunological response, and safety evaluation of OxyChips, and 4) In vivo implantation and testing of OxyChips in clinically-relevant animal models of disease. The information gained from these devices will provide a better understanding of various metabolic and disease states (e.g. cancer and peripheral vascular disease) and help in making effective clinical decisions regarding treatment and therapy. The long-term objective of this proposal is to develop implantable, oxygen-sensing probes for use in clinical electron paramagnetic resonance (EPR) oximetry. Oxygen is found in most biomolecules that are essential to living organisms, and plays a role in a number of processes in both normal and altered physiology. Once implanted, the new probes will permit repeated, noninvasive measurement of oxygen concentration in tissues. The probes could be used to track growth and/or death of tumor tissues, progression of peripheral arterial disease and muscular atrophy, and wound healing response.