Studying Electrotaxis in Microfluidic Devices

Despite more and more successful applications of microfluidic devices in electrotactic studies, there are still further improvements that need to be discussed. First, for the purposes of time-saving and screening-based studies, a high-throughput platform is highly desirable. This can possibly be done by further minimizing and automatizing the microfluidic system. Second, it will be of great interest to do single-cell analysis by combining the microfluidic device with super-resolution microscopies such as vibrational microscopy, confocal microscopy, phase microscopy and fluorescence correction/lifetime microscopy. Such applications have been reported in [89,97]. Thirdly, since in vivo cells are surrounded by various extracellular matrices, it is relevant to study the electrotaxis of cells cultured in a 3D micro-environment. As reported, electrotactic responses of lung cancer cells in ordered 3D scaffolds have been investigated [27]. However, better control over chemical or electrical stimuli inside these scaffolds is required. Finally, on the basis of successful electrotactic studies, microfluidic devices can be designed for clinical applications such as biosensors, Circulating Tumor Cell (CTC) chips and non-invasive therapeutic devices. For example, electrical stimuli are known to manipulate immune cells, as well as interrupt cancer metastasis, providing potential therapeutic approaches in treatments of immune and cancerous diseases. As micro-fabrication techniques such as soft-lithography and laser ablation become more and more improved and mature, microfluidic devices have provided biologists and biochemists a platform for investigating the physiological roles and mechanisms of electrotaxis in a more efficient way.