Living Systems Institute, University of Exeter, Exeter, Devon, EX4 4QD, UK.
Department of Physics and Astronomy, University of Exeter, Exeter, Devon, EX4 4QD, UK.
Adv Sci (Weinh). 2024 Sep;11(35):e2403195. doi: 10.1002/advs.202403195. Epub 2024 Jul 12.
Optical microcavities, particularly whispering gallery mode (WGM) microcavities enhanced by plasmonic nanorods, are emerging as powerful platforms for single-molecule sensing. However, the impact of optical forces from the plasmonic near field on analyte molecules is inadequately understood. Using a standard optoplasmonic WGM single-molecule sensor to monitor two enzymes, both of which undergo an open-to-closed-to-open conformational transition, the work done on an enzyme by the WGM sensor as atoms of the enzyme move through the electric field gradient of the plasmonic hotspot during conformational change has been quantified. As the work done by the sensor on analyte enzymes can be modulated by varying WGM intensity, the WGM microcavity system can be used to apply free energy penalties to regulate enzyme activity at the single-molecule level. The findings advance the understanding of optical forces in WGM single-molecule sensing, potentially leading to the capability to precisely manipulate enzyme activity at the single-molecule level through tailored optical modulation.
光学微腔，特别是由等离子体纳米棒增强的 whispering gallery 模式（WGM）微腔，正在成为单分子传感的强大平台。然而，等离子体近场的光学力对分析物分子的影响还没有得到充分的理解。本工作使用标准的光等离子体 WGM 单分子传感器监测两种酶，这两种酶都经历了开-闭-开的构象转变，在构象变化过程中，酶原子穿过等离子体热点的电场梯度时，WGM 传感器对酶做功的情况已经被量化。由于传感器对分析物酶所做的功可以通过改变 WGM 强度来调节，因此 WGM 微腔系统可用于施加自由能惩罚，以在单分子水平上调节酶的活性。这些发现增进了对 WGM 单分子传感中光学力的理解，有可能通过定制的光学调制来精确地在单分子水平上操纵酶的活性。
