萤火虫生物发光借助于萤光素酶在ATP、Mg2+和O2存在的条件下,通过两步反应氧化底物萤光素释放出发光信号，有着非侵袭性、操作简便、费用低廉、对仪器设备以及实验样本的生理状态要求较低等优势，已被广泛应用于生物医学领域的可视化成像分析研究，但目前萤光素底物的生物发光仍然存在着灵敏度低、给药浓度高、作用时间短、细胞和组织通透性差等缺点。申请人一直从事萤火虫生物发光可视化分析研究，已在Anal Chem、Chem Soc Rev等杂志发表多篇论文，本项目拟在大量的前期工作基础上，通过对其底物萤光素6’-位引入能改善细胞组织通透性和体内药物代谢动力学性质的环烷、杂环基团，建立和开发基于萤火虫荧光素酶/荧光素体系的新型生物发光底物并研究其生物发光活性，形成从分子探针、生物分子、细胞与动物模型的萤火虫生物发光体内可视化分析的理论和技术体系。

The reliable sensitive, convenient, affordable and non-invasive firefly bioluminescence has been emerged as a novel imaging tool in the visualizaion analysis involved in life sciences, in which depends on that firefly luciferase can catalyze the oxidation of it substrate, luciferin, in the presence of ATP, Mg2+ and oxygen, so as to emit the bioluminescence. However, the current dilemma for the firefly luciferin-luciferase bioluminescence system is that its substrate has disadvantages on low sensitivity, short duration time in vivo, high concentration up to 100 mM for in vivo imaging, as well as unreasonable cell and tissue permeability. The PI has been focusing on firefly bioluminescence system, and published several research articles in Anal Chem, Chem Soc Rev, etc. In the current project, on the basis of our fruitful preliminary results, the PI aims at obtaining novel substrates with high sensitivity for the firefly luciferin-luciferase bioluminescence system by modifying the chemical structure of luciferin and introducing cycloalkane and heterocyclic rings with high premeable and well tolerable ability in vivo at the 6'-position ,and examining these proposed substrates's bioluminescent imaging potential on the molecular, cellular and living animal levels. The successful results from this project will develop a visualization analysis platform of firefly bioluminescence, including development of molecular probe, biomolecule recognition, as well as generation of cell and animal model.