Webinar

Streaming potential and dielectrophoresis are key electrokinetic phenomena used for power generation and particle/cell trapping, respectively. Nevertheless, the practical implementation of these phenomena faces limitations stemming from the intricate fabrication processes, high expenses associated with conventional electrokinetic energy conversion or dielectrophoresis devices, and the need for skilled personnel. These challenges impede both scalability and compatibility with other analytical or point-of-care diagnostic devices for remote applications. To address this, cost-effective platforms such as micro-nanoporous structures in paper/textile microfluidic devices have been introduced. These offer capillarity-coupled-evaporation driven flow and integration with diagnostic tools for self-powered systems. A simple 'paper-and-pencil' microfluidic device achieves a 100mV streaming potential and 640pW output power, scalable to 2.1V with multiplexing. Similarly, textile-based microfluidic devices with multiplexing have the capability to consistently generate up to 12V of electrical power, enabling the illumination of LEDs for more than an hour. Conversely, a 'paper-and-pencil' microfluidic setup demonstrates controlled trapping of microparticles and biological cells through dielectrophoresis, enabling flexible preconcentrator designs for bio-analytical systems without requiring sophisticated equipment.

Electrokinetics has also played a pivotal role in the realm of active particle/micronanomotor propulsion. However, a major obstacle for these micromotors, especially in the case of chemically driven Mg-core micromotors, is their limited lifespan due to core depletion. To address this, a hybrid propulsion method has been developed. This method utilizes chemical, magnetic, and electric fields to guide micromotors from high to low conductivity mediums within intricate microfluidic systems. On the other hand, controlling the movement of these autonomous micromotors and managing multiple particles simultaneously is challenging. "Optoelectronic tweezing" (OET) addresses this by using optically patterned electrodes on a photoconductive substrate via a digital micromirror device (DMD). This dynamically regulates particle motion, shaping trajectories and enabling precise control, including self-assembly into stable structures. The system's adaptability to closed-loop operation, aided by real-time image analysis, allows these particles to function as programmable microrobots, enhancing their potential applications.