Radially actuating conducting polymer microactuators as gates for dynamic microparticle sieve based on printed microfluidics

A new radially expanding conducting polymer microactuator is presented. The radially expanding microactuators are used as electroactive gates in an electrically controlled microparticle sieve. A novel configuration to dynamically filter particles of different sizes in a microfluidic chip is conceptualized. Micropillars of SU-8 combined with conducting polymers to provide the radial actuation are positioned in a microfluidic chip with a specifically designed 3D printed housing to allow for selective filtration of microparticles with varied sizes. These pillar-shaped microactuators of polypyrrole actuate radially to function as dynamic gates for the fluidic channel, controlling the porosity of the filter allowing for the filtration of specific size of microparticles. This sieve design provides user defined channel width modulation with external stimuli. Photolithography and electrochemical polymerizations are combined with additive manufacturing to fabricate the individual functional parts of the microfluidic filter. To demonstrate the new conceptual filter design, we have shown filtration of microparticles of the sizes 60, 80, 90 and 100 µm by electrically actuating micropillars of the dynamic gate. The flow and aggregation of the microparticles were analysed at the dynamic gates to characterize the performance of the filter.