Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States.
School of Engineering and Sciences, Tecnologico de Monterrey, Monterrey, N.L. 64849, Mexico.
J Am Chem Soc. 2021 Aug 4;143(30):11544-11553. doi: 10.1021/jacs.1c04236. Epub 2021 Jul 21.
Exponential molecular amplification such as the polymerase chain reaction is a powerful tool that allows ultrasensitive biodetection. Here, we report a new exponential amplification strategy based on photoredox autocatalysis, where eosin Y, a photocatalyst, amplifies itself by activating a nonfluorescent eosin Y derivative (EYH) under green light. The deactivated photocatalyst is stable and rapidly activated under low-intensity light, making the eosin Y amplification suitable for resource-limited settings. Through steady-state kinetic studies and reaction modeling, we found that EYH is either oxidized to eosin Y via one-electron oxidation by triplet eosin Y and subsequent 1e/H transfer, or activated by singlet oxygen with the risk of degradation. By reducing the rate of the EYH degradation, we successfully improved EYH-to-eosin Y recovery, achieving efficient autocatalytic eosin Y amplification. Additionally, to demonstrate its flexibility in output signals, we coupled the eosin Y amplification with photoinduced chromogenic polymerization, enabling sensitive visual detection of analytes. Finally, we applied the exponential amplification methods in developing bioassays for detection of biomarkers including SARS-CoV-2 nucleocapsid protein, an antigen used in the diagnosis of COVID-19.
指数分子扩增，如聚合酶链反应，是一种强大的工具，可以实现超灵敏的生物检测。在这里，我们报告了一种新的基于光氧化还原自催化的指数扩增策略，其中曙红 Y，一种光催化剂，在绿光下激活非荧光曙红 Y 衍生物（EYH）来自我放大。失活的光催化剂在低强度光下稳定且快速激活，使曙红 Y 的扩增适用于资源有限的环境。通过稳态动力学研究和反应模型，我们发现 EYH 要么通过三重态曙红 Y 的单电子氧化和随后的 1e/H 转移被氧化为曙红 Y，要么被单线态氧激活，但存在降解的风险。通过降低 EYH 降解的速率，我们成功地提高了 EYH 到曙红 Y 的回收率，实现了高效的自催化曙红 Y 扩增。此外，为了展示其在输出信号方面的灵活性，我们将曙红 Y 扩增与光致显色聚合偶联，实现了对分析物的灵敏可视化检测。最后，我们应用指数扩增方法开发了用于检测生物标志物的生物测定法，包括 SARS-CoV-2 核衣壳蛋白，这是 COVID-19 诊断中使用的一种抗原。
