Abstract: In this study, dopamine was polymerized onto the surface of optically transparent ITO (or Au) electrode by auto-oxidation method. The formed polydopamine film was then protonated in pH 3 buffer solution to become positively charged which facilitates electrostatic interaction with negatively charged protoplasts. The effectiveness of the protonated polydopamine films to the adhesion of Arabidopsis thaliana protoplasts was confirmed by cyclic voltammetry and electrochemical impedance spectroscopy. In the tested range of 1000—30 000 protoplasts, the charge-transfer resistance (Rct) of the protonated polydopamine films increased with the protoplast number Ncells, and the 1/Rct displayed a linear relationship with 1/Ncells. Moreover, the dynamic adhesion test results using quartz crystal microbalance further proved that the protonated polydopamine films had good adhesion to the protoplasts. This study provides an effective method for the immobilization and sensing of protoplasts, which is an important step toward the goal of study of plant structure, function and behavior at the cellular level and the study of plant life diversity.

Key words: protonated polydopamine, arabidopsis protoplasts, interfacial adhesion, electrochemical characterization, quartz crystal microbalance

摘要： 采用自氧化方法将多巴胺(DA)聚合修饰到光透ITO(或金)电极表面上，通过缓冲溶液(pH 3)处理后形成带正电、可与带负电荷原生质体静电相互作用的表面膜。经循环伏安、电化学阻抗方法证明修饰薄膜对拟南芥原生质体黏附的有效性，在一定原生质体数目范围(1000～30 000)，质子化聚多巴胺膜界面电荷转移电阻(Rct)随原生质体数目(Ncells)增加而增加，1/Rct与1/Ncells呈线性关系。此外，石英晶体微天平动态测试结果亦证明，本方法制备的修饰薄膜对原生质体具良好的黏附效果。本研究提供了一种用于原生质体固定与传感的有效方法，为在细胞层次研究植物结构、功能与行为及植物生命多样性提供参考。

关键词: 质子化聚多巴胺, 拟南芥原生质体, 界面黏附, 电化学表征, 石英晶体微天平