Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States of America.
Department of Electrical and Computer Engineering, University of Alberta, 9107-116 St, Edmonton, Alberta T6G 2 V4, Canada.
Nano Lett. 2022 Jan 12;22(1):517-523. doi: 10.1021/acs.nanolett.1c04487. Epub 2021 Dec 28.
We show a double-functional fluorescence sensing paradigm that can retrieve nanometric pH information on biological structures. We use this method to measure the extent of protonic condensation around microtubules, which are protein polymers that play many roles crucial to cell function. While microtubules are believed to have a profound impact on the local cytoplasmic pH, this has been hard to show experimentally due to the limitations of conventional sensing techniques. We show that subtle changes in the local electrochemical surroundings cause a double-functional sensor to transform its spectrum, thus allowing a direct measurement of the protonic concentration at the microtubule surface. Microtubules concentrate protons by as much as one unit on the pH scale, indicating a charge storage role within the cell via the localized ionic condensation. These results confirm the bioelectrical significance of microtubules and reveal a sensing concept that can deliver localized biochemical information on intracellular structures.
我们展示了一种双重功能的荧光传感模式，可以在生物结构上获取纳米级 pH 值信息。我们使用这种方法来测量微管周围质子凝聚的程度，微管是一种对细胞功能至关重要的蛋白质聚合物。虽然微管被认为对局部细胞质 pH 值有深远的影响，但由于传统传感技术的限制，这很难在实验中证明。我们表明，局部电化学环境的细微变化会导致双功能传感器改变其光谱，从而可以直接测量微管表面的质子浓度。微管将质子浓缩一个 pH 单位，这表明通过局部离子凝聚，微管在细胞内起着电荷存储的作用。这些结果证实了微管的生物电学意义，并揭示了一种可以提供细胞内结构局部生化信息的传感概念。
