Development of Cavity-Enhanced Single-Molecule Electronic and Vibrational Spectroscopy for Mechanistic Studies of Biomolecules

用于生物分子机理研究的腔增强单分子电子和振动光谱学的发展

• 批准号: 10470395
• 负责人: Randall H Goldsmith
• 金额: $ 28.92万
• 依托单位: UNIVERSITY OF WISCONSIN-MADISON
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-09-05 至 2024-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10470395
• 关键词: Biochemical; Biological; Chemicals; Cobalt; Complex; Coupling; Development; Devices; Diagnostic; Dyes; Environment; Evaluation; Fiber; Film; Fluorescence; Geometry; Glass; In Vitro; Individual; Investigation; Label; Learning; Light; Measurement; Metals; Methods; Microbubbles; Molecular; Monitor; Optics; Performance; Polymers; Positioning Attribute; Production; Property; Pump; Raman Spectrum Analysis; Sampling; Series; Signal Transduction; Specificity; Spectrum Analysis; Surface; System; Techniques; Technology; Temperature; Testing; Thermometers; Time; Vitamin B 12; absorption; aqueous; biomaterial compatibility; biophysical techniques; chemical bond; chemical reaction; design; indexing; insight; instrumentation; metalloenzyme; molecular dynamics; nanoparticle; oxidation; particle; photonics; plasmonics; silicon nitride; single molecule; tool; vibration; waveguide

Development of Cavity-Enhanced Single-Molecule Electronic and Vibrational Spectroscopy for Mechanistic Studies of Biomolecules Single-molecule (SM) measurements are a powerful mechanistic tool because they allow multi-step unsynchro- nized dynamics to be directly observed. However, most SM observations rely on fluorescence, which lacks the sensitivity to determine oxidation state, the chemical specificity to elucidate distortion of a particular chemical bond, and requires a fluorescent label. Such information would revolutionize how biochemical mechanisms are determined and could be provided by a method of performing electronic absorption and vibrational spectroscopy on single operational biomolecules. However, surface-enhanced Raman spectroscopy (SERS) is not is suited for probing complex biomolecules, as the method requires intimate contact between the part of the biomolecule to be probed (which may be at the interior), and a metal surface. Similarly, methods exist for performing SM elec- tronic absorption spectroscopy but they lack the required sensitivity or biocompatibility for biomolecules. Thus, a new method is needed to allow SM investigations of in vitro molecular dynamics for mechanistic investigations. We propose the use of optical microcavities as platforms for ultrasensitive SM electronic and vibrational spectroscopy. In one geometry, microcavities are used as highly sensitive thermometers, capable of detecting the heat dissipated by non-fluorescent molecules upon photoexcitation. In this way, non-fluorescent and potentially even weakly absorbing spectral features, such as those diagnostic of the coordination environment of a metal- loenzyme can be elucidated. In a second complimentary geometry we take advantage of the Purcell Effect, which can significantly enhance scattering rates in optical microcavities with small mode volumes and high Quality factors. While SERS requires essentially Van der Waals contact with a plasmonic surface, the microcavity en- hancement can act at a distance of up to ~100 nm from a dielectric surface, making it suitable for probing bio- molecules without significant perturbation. We have now demonstrated the core concepts behind these two strat- egies. In Specific Aims 1-3, we will bring online and evaluate three new microcavity systems that promise to significantly enhance our measurement capacity enough to lay a concrete path to biomedical applications: planar silicon nitride ring resonators (SA 1), fiber Fabry-Perot microcavities (SA 2), and silicon nitride nanobeams (SA3). In all cases we will perform spectroscopy on a series of particles and molecules of increasing challenge, pushing toward the monitoring of a single working metalloenzyme. Supporting calculations suggest that these new resonator geometries will increase our molecular signals by orders of magnitude. Our long-term objective is to bring a new, highly informative, and even disruptive biophysical technique to bear on biological molecules to understand how they operate, change in time, are regulated, and fail.

腔增强单分子电子和振动光谱学的发展 生物分子的机理研究 单分子（SM）测量是一种强大的机械工具，因为它们允许多步不同步 可以直接观察到动态变化。然而，大多数 SM 观察依赖于荧光，而荧光缺乏 确定氧化态的灵敏度，阐明特定化学物质扭曲的化学特异性 键，并且需要荧光标记。这些信息将彻底改变生化机制的方式 确定并可以通过执行电子吸收和振动光谱的方法提供 单一可操作的生物分子。然而，表面增强拉曼光谱 (SERS) 并不适合 探测复杂的生物分子，因为该方法需要生物分子部分之间的密切接触 被探测（可能在内部）和金属表面。类似地，存在用于执行 SM 电的方法 电子吸收光谱，但它们缺乏生物分子所需的灵敏度或生物相容性。因此， 需要一种新方法来进行体外分子动力学的 SM 研究以进行机械研究。 我们建议使用光学微腔作为超灵敏 SM 电子和振动平台 光谱学。在一种几何结构中，微腔被用作高灵敏度温度计，能够检测 非荧光分子在光激发时耗散的热量。通过这种方式，非荧光且潜在的 甚至是弱吸收的光谱特征，例如那些诊断金属配位环境的光谱特征 可以阐明loenzyme。在第二个互补几何中，我们利用珀塞尔效应， 可以显着提高光学微腔中的散射率，模式体积小且质量高 因素。虽然 SERS 本质上需要范德华与等离子体表面接触，但微腔 增强可以在距电介质表面约 100 nm 的距离处起作用，使其适合探测生物 分子无明显扰动。我们现在已经展示了这两个策略背后的核心概念 例如。在具体目标 1-3 中，我们将上线并评估三种新的微腔系统，这些系统有望 显着增强我们的测量能力，足以为生物医学应用奠定具体的道路：平面 氮化硅环形谐振器 (SA 1)、光纤法布里-珀罗微腔 (SA 2) 和氮化硅纳米梁 （SA3）。在所有情况下，我们都会对一系列日益增加的挑战的粒子和分子进行光谱分析， 推动对单一工作金属酶的监测。支持计算表明这些 新的谐振器几何形状将使我们的分子信号增加几个数量级。我们的长期目标 是带来一种新的、信息丰富的、甚至是颠覆性的生物物理技术来研究生物分子 了解它们如何运作、随时间变化、受到监管以及失败。