Seo Young Yoon

Cytoskeletal Actin Dynamics are Involved in Pitch‐Dependent Neurite Outgrowth on Bead Monolayers

Neurite outgrowth is an important preceding step for the development of nerve systems. Given that the in vivo environments of neurons consist of numerous hierarchical micro/nanotopographies, there have been many efforts to investigate the relationship between neuronal behaviors and surface topography. The acceleration of neurite outgrowth was recently reported on surfaces with a periodic nanotopography, but the biological mechanism has not yet been elucidated. In this work, the initial neurite development of hippocampal neurons on assembled silica beads with diameters ranging from 700 to 1800 nm was explored. The acceleration of neurite outgrowth increased with the surface-pitch size and leveled off after a pitch of 1 μm. Biochemical analysis indicated that cytoskeletal actin dynamics were primarily responsible for the recognition of surface topography. This work contributes to the emerging research field of topographical neurochemistry, as well as applied fields including neuroregeneration and neuroprosthetics.

Local liquid phase deposition of silicon dioxide on hexagonally close-packed silica beads.

Liquid phase deposition (LPD) is a useful method for the production of oxide film with low reaction temperature and production cost. With the report that the LPD of oxide films is conformally processed with uniform thickness and composition, there has been significant attention given to investigating its kinetic controls and growth mechanism on the flat surface. In this work, we explored the LPD of silicon dioxide on the hexagonally close-packed silica beads array as a nanostructured surface. The deposition and etching reactions of SiO2 occurred locally and simultaneously on silica beads, and were distinguished from the amount of fumed silica added in LPD solution. From locally competitive reactions, we obtained the anisotropic morphology of close-packed silica beads, and proposed a mechanism for the local LPD of SiO2 driven by nanostructured surfaces. This work contributes highly to improve metal oxide-based engineering, and also provide greater insight into the topography-driven LPD.

Liquid phase deposition of silica on the hexagonally close-packed monolayer of silica spheres

Liquid phase deposition is a method used for the nonelectrochemical production of polycrystalline ceramic films at low temperatures, most commonly silicon dioxide films. Herein, we report that silica spheres are organized in a hexagonal close-packed array using a patterned substrate. On this monolayer of silica spheres, we could fabricate new nanostructures in which deposition and etching compete through a modified LPD reaction. In the early stage, silica spheres began to undergo etching, and then, silica bridges between the silica spheres appeared by the local deposition reaction. Finally, the silica spheres and bridges disappeared completely. We propose the mechanism for the formation of nanostructure.