Investigation of Reactive Radical Intermediates for the Development of X-ray Photonanochemistry

X射线光纳米化学发展中活性自由基中间体的研究

• 批准号: 1905338
• 负责人: Gang-Yu Liu
• 金额: $ 35.45万
• 依托单位: University of California-Davis
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-08-15 至 2022-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1905338&HistoricalAwards=false
• 关键词: Investigation; Reactive; Radical; Intermediates; Development

One of the most important molecules in our life is DNA, which can be broken into pieces in water after exposure to powerful, invisible X-ray radiation. Although X-ray-induced damage to DNA can cause harmful effects to our health, it can also be used beneficially in a number of applications including radiation therapy for cancer treatment. The rate of such damage is found to be accelerated by the presence of tiny metal particles, such as gold particles whose dimensions are on the order of a small fraction of the diameter of a human hair. However, the cause for acceleration in the speed of DNA damage is not fully understood. With the support from the Macromolecular, Supramolecular and Nanochemistry Program of the NSF Division of Chemistry, Professor Guo at the University of California at Davis aims to develop a novel approach to achieve a better fundamental understanding of this important and complex chemical process. The outcome of this research can potentially help scientists tailor these important reactions for applications ranging from disease treatment to catalytic cleavage of synthetic polymers. This interdisciplinary project at the interface of chemistry, biology, and materials science provides valuable research training opportunities and improves competitiveness of students including underrepresented minority students.The X-ray induced DNA strand breaking process in water is generally believed to start with the generation of reactive oxygen species (ROS) by X-rays. The ROS then react with DNA to form reactive DNA intermediates, which subsequently leads to the breaking of the DNA strands. While it was discovered recently that this process can be accelerated in the presence of gold nanoparticles, the mechanism for such catalytic process is not understood. In order to decipher these important and complex reactions, Professor Guo's group develops a novel approach to generate and monitor the reactive intermediates. The approach features nanoreactors irradiated by an X-ray beam. The nanoreactors containing catalyst assemblies are designed and synthesized to control the chemical environment, and the timing of X-ray irradiation, the size of the X-ray beam, and the position of the catalyst assemblies in the nanoreactors are controlled so that the conversion of reactive intermediates to broken DNA strands can be spatially and temporally separated from the production of ROS. Such separation simplifies the interpretation process and allows the identification of the intermediates and measurement of their lifetime, leading to the elucidation of the reaction mechanisms. The anticipated outcome of this project is the development of a novel technique that is useful not only for elucidating X-ray induced chemical reactions (such as DNA strand breakage) but also for controlling chemical reactions that can be used to harvest or detect X-rays through the conversion of X-ray energy to chemical energy.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

我们生命中最重要的分子之一是DNA，在暴露于强大的不可见的X射线辐射后，它可以在水中破碎成碎片。 虽然X射线对DNA的损伤会对我们的健康造成有害影响，但它也可以用于许多应用，包括癌症治疗的放射治疗。 发现这种损伤的速率由于微小金属颗粒的存在而加速，例如金颗粒，其尺寸大约是人类头发直径的一小部分。 然而，DNA损伤速度加快的原因还没有完全了解。 在NSF化学部大分子，超分子和纳米化学计划的支持下，加州大学戴维斯分校的郭教授旨在开发一种新的方法，以更好地理解这一重要而复杂的化学过程。 这项研究的结果可能有助于科学家定制这些重要的反应，用于从疾病治疗到合成聚合物的催化裂解等应用。 这个跨学科的研究项目是化学、生物学和材料科学的交叉点，为学生（包括少数民族学生）提供了宝贵的研究培训机会，并提高了学生的竞争力。通常认为，水中X射线诱导的DNA链断裂过程始于X射线产生活性氧（ROS）。 然后ROS与DNA反应形成反应性DNA中间体，随后导致DNA链断裂。 虽然最近发现这个过程可以在金纳米粒子的存在下加速，但这种催化过程的机制尚不清楚。 为了破译这些重要而复杂的反应，郭教授的研究小组开发了一种新的方法来产生和监测活性中间体。 该方法的特点是用X射线束照射纳米反应器。设计和合成含有催化剂组件的纳米反应器以控制化学环境，并且控制X射线照射的定时、X射线束的大小和催化剂组件在纳米反应器中的位置，使得活性中间体向断裂DNA链的转化可以在空间和时间上与ROS的产生分离。 这种分离简化了解释过程，并允许鉴定中间体和测量其寿命，从而阐明反应机理。 该项目的预期成果是开发一种新的技术，不仅可用于阐明X射线诱导的化学反应，（例如DNA链断裂），而且还用于控制化学反应，所述化学反应可用于通过X-射线的转换来收获或检测X射线。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准。