4D Biofabrication of fibrous artificial nerve graft for neuron regeneration

In this paper, we describe the application of the 4D biofabrication approach for the fabrication of artificial nerve graft. Bilayer scaffolds consisting of uniaxially aligned polycaprolactone-poly(glycerol sebacate) (PCL-PGS) and randomly aligned methacrylated hyaluronic acid (HA-MA) fibers were fabricated using electrospinning and further used for the culture of PC-12 neuron cells. Tubular structures form instantly after immersion of fibrous bilayer in an aqueous buffer and the diameter of obtained tubes can be controlled by changing bilayer parameters such as the thickness of each layer, overall bilayer thickness, and medium counterion concentration. Designed scaffolds showed a self-folded scroll-like structure with high stability after four weeks of real-time degradation. The significance of this research is in the fabrication of tuneable tubular nerve guide conduits that can simplify the current existing clinical treatment of neural injuries. © 2020 The Author(s). Published by IOP Publishing Ltd

Reversibly Photoswitchable High‐Aspect Ratio Surfaces

Herein, the fabrication of light‐sensitive high‐aspect ratio surfaces with switchable topography using melt‐electrowriting of shape‐memory polymers and deposition of light‐to‐heat converting black ink on it by dip coating is reported on. The lamellae exposed to low temperatures are hard and cannot be deformed by water droplets. The temperature reached upon illumination of surfaces is close to the melting point of the soft segment of the polyurethane that leads to softening of the polymer. Due to this, it is possible to locally deform and recover the light‐softened surface structures by water droplets deposited on lamellae. The deformed state can be fixed by cooling down resulting in the crystallization of the polymer. Thus, the reversibility of local deformation can be achieved. Finally, the application of the developed approach and materials for the fabrication of smart light‐controlled valves is demonstrated, which can be used for the controlled mixing of fluids in microfluidic devices

Optical properties of thin metal films with nanohole arrays on porous alumina–aluminum structures

Enhanced plasmonic attenuation of reflection is observed in a gold–alumina–aluminum multilayer system near the interferometric anti-reflection condition.</p