Conventional macroscopic electrochemical sensors are typically used by immersing their sensing components in sample solutions. Microfabricated electrochemical sensors can be coupled with solution-processing functions in devices of small footprints to achieve high-performance sensing. In this context, microfluidics is an essential technology, enabling the manipulation of very small volumes of solutions in microfabricated flow channels and reaction chambers. To control fluid movement, air pressure is commonly applied. In addition to continuous flow systems, the use of discrete solution droplets facilitates processing of multiple solutions. Various techniques have been proposed to process solutions including mixing and exchange of solutions. Dielectrophoresis, a method that moves dielectric particles via gradient of electric fields, can be employed to concentrate cells in the vicinity of electrodes and is often coupled with impedimetric sensing devices. For simultaneous processing across multiple flow channels and reaction chambers, centrifugal force can be used, typically implemented via a rotating disk. Electrowetting-on-dielectric, which modulates surface wettability, is also used to mobilize droplets of solutions and perform electrochemical sensing. These techniques enable not only simple injection or transport of solutions but also more complicated procedures such as volume measurement, mixing, sorting, exchange of solutions, and concentration of analytes. Furthermore, freeze-dried matrices with immobilized molecules can rapidly complete component mixing, which is particularly effective for enzyme activity measurements.