Finney Tanner J, Frank Skye L, Bull Michael R, Guy Robert D, Kuhl Tonya L
Department of Chemical Engineering, University of California, Davis, CA 95616, United States.
Department of Mathematics, University of California, Davis, CA 95616, United States.
Adv Mater Interfaces. 2023 Jan 17;10(2). doi: 10.1002/admi.202201808. Epub 2022 Nov 18.
Polydiacetylene (PDA) Langmuir films are well known for their blue to red chromatic transitions in response to a variety of stimuli, including UV light, heat, bio-molecule bindings and mechanical stress. In this work, we detail the ability to tune PDA Langmuir films to exhibit discrete chromatic transitions in response to applied mechanical stress. Normal and shear-induced transitions were quantified using the Surface Forces Apparatus and established to be binary and tunable as a function of film formation conditions. Both monomer alkyl tail length and metal cations were used to manipulate the chromatic transition force threshold to enable discrete force sensing from ~50 to ~500 nN μm for normal loading and ~2 to ~40 nN μm for shear-induced transitions, which are appropriate for biological cells. The utility of PDA thin-film sensors was demonstrated with the slime mold . The fluorescence readout of the films enabled: the area explored by to be visualized, the forces involved in locomotion to be quantified, and revealed novel puncta formation potentially associated with sampling its environment.
聚二乙炔（PDA）朗缪尔膜因其在包括紫外线、热、生物分子结合和机械应力等多种刺激下从蓝色到红色的颜色转变而闻名。在这项工作中，我们详细阐述了调节PDA朗缪尔膜以使其在施加机械应力时呈现离散颜色转变的能力。使用表面力仪对法向和剪切诱导的转变进行了量化，并确定其为二元的且可根据成膜条件进行调节。单体烷基尾长和金属阳离子都被用于操纵颜色转变力阈值，以实现法向加载时约50至约500 nN/μm以及剪切诱导转变时约2至约40 nN/μm的离散力传感，这适用于生物细胞。用黏菌证明了PDA薄膜传感器的实用性。薄膜的荧光读数能够：可视化被探索的区域，量化运动中涉及的力，并揭示可能与感知其环境相关的新的亮点形成。
