Frank Bradley D, Antonietti Markus, Giusto Paolo, Zeininger Lukas
Department of Colloid Chemistry, Max Planck Institute of Colloids and Interfaces, Am Mühlenberg 1, 14476 Potsdam, Germany.
J Am Chem Soc. 2023 Nov 7;145(45):24476-81. doi: 10.1021/jacs.3c09084.
Intentional generation, amplification, and discharging of chemical gradients is central to many nano- and micromanipulative technologies. We describe a straightforward strategy to direct chemical gradients inside a solution via local photoelectric surface charging of organic semiconducting thin films. We observed that the irradiation of carbon nitride thin films with ultraviolet light generates local and sustained surface charges in illuminated regions, inducing chemical gradients in adjacent solutions via charge-selective immobilization of surfactants onto the substrate. We studied these gradients using droplet force gradient sensors, complex emulsions with simultaneous and independent responsive modalities to transduce information on transient gradients in temperature, chemistry, and concentration via tilting, morphological reconfiguration, and chemotaxis. Fine control over the interaction between local, photoelectrically patterned, semiconducting carbon nitride thin films and their environment yields a new method to design chemomechanically responsive materials, potentially applicable to micromanipulative technologies including microfluidics, lab-on-a-chip devices, soft robotics, biochemical assays, and the sorting of colloids and cells.
化学梯度的有意产生、放大和释放是许多纳米和微操纵技术的核心。我们描述了一种直接的策略，通过有机半导体薄膜的局部光电表面充电来引导溶液中的化学梯度。我们观察到，用紫外光照射氮化碳薄膜会在光照区域产生局部且持续的表面电荷，通过表面活性剂在基底上的电荷选择性固定，在相邻溶液中诱导化学梯度。我们使用液滴力梯度传感器、具有同时且独立响应模式的复杂乳液来研究这些梯度，通过倾斜、形态重构和趋化作用来转导关于温度、化学性质和浓度的瞬态梯度信息。对局部光电图案化的半导体氮化碳薄膜与其环境之间相互作用的精细控制产生了一种设计化学机械响应材料的新方法，该方法可能适用于包括微流体、芯片实验室设备、软机器人技术、生化分析以及胶体和细胞分选在内的微操纵技术。
