A bottom-up approach to the rational design of new bioluminescence emitters

这项研究将提高我们对生物发光的分子水平的理解，为合理设计新的近红外发射体用于先进的生物发光成像应用奠定基础。生物发光是生物有机体发出的光。这是自然界最壮观的现象之一，并将继续挑战那些试图理解它的人。萤火虫发出的黄绿色光芒是生物发光中最明亮、最美丽的例子之一。生化过程包括小分子(荧光素)被酶(荧光素酶)催化氧化，形成电子激发的草基荧光素，然后通过发光松弛到基态。利用生物发光进行成像应用已经使生物科学发生了革命性的变化。生物发光成像现在是可视化活体中分子和细胞过程的标准工具。然而，由于血液和组织对可见光的吸收，深层组织的敏感性降低，限制了更先进的应用。新的远红外线和近红外生物发光系统可用于提高深层组织的灵敏度和分辨率，但它们的亮度和狭窄的光谱范围限制了它们。对明亮、多色、远红和近红外发射器的需求十分迫切。到目前为止，对生物发光系统的修改一直依赖于渐进式变化和基于小型库的方法。我们建议使用一种全新的、自下而上的方法。我们将使用最先进的光谱测量和量子化学计算来了解远红和近红外荧光素的哪些电子态和分子运动在降低生物发光亮度的竞争非辐射弛豫路径中是重要的，我们还将了解荧光素酶如何调节生物发光波长。然后，我们将利用这些信息来设计新的、明亮的生物发光发射器，用于多色、远红和近红外生物发光成像。

This research will improve our molecular level understanding of bioluminescence for the rational design of new near-infrared emitters for advanced bioluminescence imaging applications. Bioluminescence is the emission of light by living organisms. It is one of Nature's most spectacular phenomena and continues to challenge those who try to understand it. The yellow-green glow of fireflies is one of the brightest and most beautiful examples of bioluminescence. The biochemical process involves the catalytic oxidation of a small molecule (luciferin) by an enzyme (luciferase) to form an electronically excited oxyluciferin that subsequently relaxes to its ground state by emitting light. Harnessing bioluminescence for imaging applications has revolutionised the biosciences. Bioluminescence imaging is now a standard tool for visualising molecular and cellular processes in vivo. However, more advanced applications are limited by reduced sensitivity in deep tissue arising from the absorption of visible light by blood and tissue. New far-red and near-infrared bioluminescence systems for enhanced sensitivity and resolution in deep tissue have recently become available; however, they are limited by their brightness and narrow spectral range. There is a pressing need for bright, multicolor, far-red and near-infrared emitters. To date, modifications to bioluminescent systems have relied on incremental changes and small library-based approaches. We propose to use a fundamentally new, bottom-up approach. We will use state-of-the-art spectroscopy measurements and quantum chemistry calculations to learn which electronic states and molecular motions of far-red and near-infrared luciferins are important in the competing non-radiative relaxation pathways that reduce the brightness of bioluminescence and we will learn how luciferase enzymes tune the bioluminescence wavelength. We will then use this information to design new, bright bioluminescent emitters for multicolour, far-red and near-infrared bioluminescence imaging.