集成电极的复合混沌混合芯片的快速制备及表征

Rapid preparation and characterization of chaotic mixing chip integrated indium tin oxide electrodes

试剂的有效混合是化学和生化反应的前提条件,因此混合成为微全分析系统的重要功能单元。本文介绍了一种通道中集成氧化铟锡(ITO)电极的聚二甲基硅氧烷(PDMS)-玻璃复合混沌混合芯片的快速制备方法,对PDMS的混合通道表面进行了硅溶胶改性。首次用集成的电极和酸碱反应过程中的电导变化对其混合效果进行了评价。利用玻璃各向同性刻蚀特点,一次曝光和一次刻蚀得到了混沌混合微通道结构的母板。利用光辅助原位聚合的方法快速制备了与母板微结构互补的聚甲基丙烯酸甲酯(PMMA)阳模,利用PDMS原位聚合的方法复制得到了与玻璃母板结构相同的混沌混合通道结构的芯片。用电导法对芯片的混合有效性进行了表征。PDMS复制芯片与ITO玻璃永久封合即得全透明的复合混沌混合芯片。本文介绍的加工方法无需二次曝光及SU-8光刻胶,容易多次复制,在微流控分析芯片中将有广泛应用。

Effective mixing of reactants is a prerequisite to chemical and biochemical reactions, thus mixing becomes an important functional unit in micro- total analytical system. In this paper, a simple procedure of reproducing a hybrid chaotic mixer made of dimethylsiloxane （PDMS） - glass in ordinary laboratory is presented. Indium tin oxide （ITO） micro - electrodes are integrated in the mixing channel, and the surface of the PDMS micro - channels is modified by using sol - gel of silica. The mixing performance is characterized for the first time by conductivity of an acid -base reaction with the integrated electrodes. The glass mother mold was prepared by isotropic wet etching of glass, and the mixing channel together with the sub micro -structure was formed by one -step exposure and one -step etching. Positive mold with complementary micro - structure to that of the mother mold （negative） was prepared by UV assisted in situ - polymerization of polymethyhnethacrylate （ PMMA）, and PDMS replication of the positive PMMA mold was achieved by thermal in situ polymerization. Hybrid chip mixer was obtained by sealing the PDMS replica with a glass slide with ITO electrodes. The effective mixing performance was confirmed both by conductivity detection and fluorescence imaging. The method introduced here is easy to implement in common laboratories without double exposures and SU -8 photoresist, and will find wide applications in the microfluidic analytical chips.