Experimental and theoretical study on the microparticle trapping and release in a deformable nano-sieve channel.

Deformable microfluidics may be potentially used in cell manipulation, optical sensing, and imaging applications, and have drawn considerable scientific interests in the recent past. The excellent tunability of deformable microfluidic devices can provide controllable capture, deposition, and target release. We demonstrated a one-dimensional nano-sieve device to capture microparticles from suspensions. Size-selective capturing and release of micro- and nanoparticles was achieved by simply adjusting the flow rate. Almost all the microparticles were trapped in the nano-sieve device at a flow rate of 20 μl min. Increasing the flow rate induces a hydrodynamic deformation of the roof of the compliant device and allows most of the microparticles to pass through the channel. We also established a theoretical model based on computational fluid dynamics to reveal the relationship of the hydrodynamically induced deformation, channel dimensions, and capture efficiency that supports and rationalizes the experimental data. We have predicted the capture efficiency of micro-and nanoparticles in a nano-sieve device with various geometries and flow rates. This study may be important to the optimization of next generation deformable microfluidics for efficient micro- and nanostructure manipulations.