We demonstrate a facile method to fabricate a recyclable cell-alignment scaffold using nanogrooves based on sublimable liquid crystal (LC) material. Randomly and uniaxially arranged smectic LC structures are obtained, followed by sublimation and recondensation processes, which directly produce periodic nanogrooves with dimensions of a couple of hundreds of nanometers. After treatment with osmium tetroxide (OsO4), the nanogroove can serve as a scaffold to efficiently induce directed cell growth without causing cytotoxicity, and it can be used repeatedly. Together, various cell types are applied to the nanogroove, proving the scaffold’s broad applicability. Depending on the nanotopography of the LC structures, cells exhibit different morphologies and gene expression patterns, compared to cells on standard glass substrates, according to microscopic observation and qPCR. Furthermore, cell sheets can be formed, which consist of oriented cells that can be repeatedly formed and transferred to other substrates, while maintaining its organization. We believe that our cell-aligning scaffold may pave the way for the soft material field to bioengineering, which can involve fundamentals in cell behavior and function, as well as applications for regenerative medicine.

Electron microscopy (EM) is a technique that observes the complex microstructure of a sample with a resolution of several Å using high-energy electrons with a short wavelength. It is very effective for visualizing nanostructures that would not be observed with an optical microscope. However, there are limitations in that the observation must be carried out with a very thin film in a vacuum, and the electron beam may damage the samples. The sample may be out of the desired state or damaged, and the image may be distorted. As a solution to these problems, a freeze-fracture technique can be proposed. Freeze-fracture method is a process of rapidly freezing a sample and then fracturing it to produce a metal replica of the morphology of the bulk of the surface. This article includes an overview and principles of freeze-fracture techniques and examples of analysis of various soft structures.

Using improper wound care materials may cause impaired wound healing, which can involve scar formation and infection. Herein, we propose a facile method to fabricate a cellalignment scaffold, which can effectively enhance cell growth and migration, leading to the reproduction of cellular arrangements and restoration of tissues. The principle is scratching a diamond lapping film that gives uniaxial nanotopography on substrates. Cells are seeded to follow the geometric cue via contact guidance, resulting in highly oriented cell alignment. Remarkable biocompatibility is also demonstrated by the high cell viability on various substrates. In vivo studies in a wound healing model in mice show that the scratched film supports directed cell guidance on the nanostructure, with significantly reduced wound areas and inhibition of excessive collagen deposition. Rapid recovery of the epidermis and dermis is also shown by histological analyses, suggesting the potential application of the scratching technique as an advanced wound dressing material for effective tissue regeneration.