Sorting differentiated mammalian cells using deterministic lateral displacement microfluidic devices.

Separation of differentiated and undifferentiated cells without labeling is required for cell analyses and clinical application of cultured differentiated cells in vitro. To proceed with the passive separation of differentiated cells inside a clean bench, we developed a system of deterministic lateral displacement (DLD) microfluidic devices and applied this system to sort differentiated cells in vitro. The fluid flow is driven by compressed air to the buffer.

Microvortex-induced turbulent mixing for reconstitution of high-density lipoprotein-mimicking nanoparticles with aggregation-prone phosphatidylcholine.

Lipid nanoparticles often contain a phosphatidylcholine with a long chain fatty acid, 1,2-distearoyl--3-phosphocholine (DSPC). However, their preparation often encounters difficulties such as the inability to yield <20 nm nanoparticles due to the aggregation-prone behavior of DSPC. High-density lipoproteins (HDLs) are ∼10 nm protein-bound lipid nanoparticles in our body, and microfluidic preparations of HDL-mimicking nanoparticles (μHDL) have been reported.

Arrangement of a nanostructure array to control equilibrium and nonequilibrium transports of macromolecules.

Exploiting the nonequilibrium transport of macromolecules makes it possible to increase the separation speed without any loss of separation resolution. Here we report the arrangement of a nanostructure array in microchannels to control equilibrium and nonequilibrium transports of macromolecules. The direct observation and separation of macromolecules in the nanopillar array reported here are the first to reveal the nonequilibrium transport, which has a potential to overcome the intrinsic trade-off between the separation speed and resolution.

DNA separation in nanowall array chips.

A nanowall array structure was fabricated on a quartz chip as a separation matrix of DNA fragments, and a 30 s separation was realized for a mixture of DNA fragments (48.5 and 1 kbp fragments) by applying the electric voltage. A longer DNA fragment migrates faster than a shorter one in a nanowall array chip, and it is completely different from the separation of DNA based on gel electrophoresis, nanopillar chips, and nanoparticle array chips.