Arrangement of a Nanostructure Array To Control Equilibrium and Nonequilibrium Transports of Macromolecules

Abstract

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.

A millisecond micro-RNA separation technique by a hybrid structure of nanopillars and nanoslits

“…Therefore, the mechanism of “torque-assisted escape” cannot be directly applied to DNA within this size range. This size criteria of “torque-assisted escape” agrees with our previous report24, which showed that the applicable size range can be expanded to nearly 1,000 bp inside a 4,000-nm-tall nanopillar array system. In this case, we can disregard the physical interaction of DNA in the direction of the z-axis.…”

“…states that under strong electric fields, larger polymers will elute faster from the nano-confinement, than will the smaller ones, via “torque-assisted escape”, if these polymers, such as DNA molecules, are sufficiently short to be rigid and straight. We have recently demonstrated that this theory can be applied to include molecules with weights of up to 1,000 bp; these do not behave as rigid and straight polymers, but the higher electric field (~500 V/cm) enhances the resolution of separation and shortens the time24. Because the hybrid structure of nanopillars and nanoslits converges with the electric field and generates a strong electric force, non-equilibrium transport was achieved in a few hundreds of a millisecond.…”

Multi-Dimensional Nanostructures for Microfluidic Screening of Biomarkers: From Molecular Separation to Cancer Cell Detection

“…This alignment enables rapid transit through the microchannel without interference with nanopillars, whereas smaller molecules that are poorly aligned with the electric field experience more physical interactions with the pillars (Figure 6a). Using this square nanopillar array, Yasui et al was able to separate four different sized DNA molecules at good resolutions within 60 s 90 .…”

“…Larger DNA fragments experience a stronger torque that aligns them along the electric field, enabling a straight projection through the array. Figure adapted from reference 90. (b) Ciliated micropillars enable molecular separation on a multitude of levels, separating cells, debris, and proteins from desired exosomes.…”

Introductory Chapter: DNA as Nanowires

“…Numerous advantages of nano-and micro-biodevices include the separation technologies, HPLC and capillary electrophoretic separation of DNA, nanopillar devices for the ultra-fast separation of DNA and proteins, nanoball materials for the fast separation of wide range of DNA fragments and the nanowire devices for ultra-fast separation of DNA, RNA, and proteins. The studies about these devices have been carried out by Prof. Yoshinobu Baba and the research group [1][2][3][4][5][6][7][8][9][10][11][12]. The nanopillar, nanowall, nanoslit, and nanopore structures were designed by the top down or semiconductor nano-fabrication technology, while the nanoball, nanowire, nanoparticles and the quantum dot structures are designed by the use of bottom up or self-assembled nano-fabrication technology.…”