Zheng Jianlu, Jo Seiko, Chen Jiali, Das Bratati, Juhasz Levente, Cabral Horacio, Sugihara Kaori
Institute of Industrial Science, The University of Tokyo, 4-6-1 Komaba, Meguro-Ku, Tokyo 153-8505, Japan.
Department of Physical Chemistry, University of Geneva, Quai Ernest Ansermet 30, 1211 Geneva 4, Switzerland.
Anal Chem. 2023 Aug 1;95(30):11335-11341. doi: 10.1021/acs.analchem.3c01433. Epub 2023 Jul 19.
Polydiacetylene (PDA) is a popular mechanochromic material often used in biosensing. The effect of its headgroup-headgroup interactions on thermochromism such as pH or salt concentration dependency has been extensively studied before; however, their effect on mechanochromism at the nanoscale is left unstudied. In this work, nanofriction force microscopy and fluorescence microscopy were combined to study the effect of pH and ionic strength on the polydiacetylene (PDA) force sensitivity at the nanoscale. We found that the increase in pH from 5.7 to 8.2 caused an 8-fold enhancement in force sensitivity. The elevation of NaCl concentration from 10 to 200 mM also made the PDA 5 times more force-sensitive. These results suggest that the PDA force sensitivity at the nanoscale can be conveniently enhanced by "pre-stimulation" with pH or ionic strength.
聚二乙炔（PDA）是一种常用于生物传感的热门机械变色材料。此前已对其头基-头基相互作用对热致变色（如pH或盐浓度依赖性）的影响进行了广泛研究；然而，它们在纳米尺度上对机械变色的影响尚未得到研究。在这项工作中，结合了纳米摩擦力显微镜和荧光显微镜来研究pH和离子强度对纳米尺度上聚二乙炔（PDA）力敏感性的影响。我们发现，pH从5.7增加到8.2会导致力敏感性提高8倍。NaCl浓度从10 mM升高到200 mM也使PDA的力敏感性提高了5倍。这些结果表明，通过用pH或离子强度进行“预刺激”，可以方便地提高纳米尺度上PDA的力敏感性。
