Two-Photon Polymerization of Butterfly Wing Scale Inspired Surfaces with Anisotropic Wettability.

Wings of Morph aega butterflies are natural surfaces that exhibit anisotropic liquid wettability. The direction-dependent arrangement of the wing scales creates orientation-turnable microstructures with two distinct contact modes for liquid droplets. Enabled by recent developments in additive manufacturing, such natural surface designs coupled with hydrophobicity play a crucial role in applications such as self-cleaning, anti-icing, and fluidic manipulation. However, the interplay among resolution, architecture, and performance of bioinspired structures is barely achieved. Herein, inspired by the wing scales of the Morpho aega butterfly, full-scale synthetic surfaces with anisotropic wettability fabricated by two-photon polymerization are reported. The quality of the artificial butterfly scale is improved by optimizing the laser scanning strategy and the objective lens movement path. The corresponding contact angles of water on the fabricated architecture with various design parameters are measured, and the anisotropic fluidic wettability is investigated. Results demonstrate that tuning the geometrical parameters and spatial arrangement of the artificial wing scales enables anisotropic behaviors of the droplet's motion. The measured results also indicate a reverse phenomenon of the fabricated surfaces in contrast to their natural counterparts, possibly attributed to the significant difference in equilibrium wettability between the fabricated microstructures and the natural Morpho aega surface. These findings are utilized to design next-generation fluid-controllable interfaces for manipulating liquid mobility on synthetic surfaces.

TREM2 Inhibits Tau Hyperphosphorylation and Neuronal Apoptosis via the PI3K/Akt/GSK-3ß Signaling Pathway In vivo and In vitro.

Triggering receptor expressed on myeloid cells-2 (TREM2), a cell surface receptor mainly expressed on microglia, has been shown to play a critical role in Alzheimer's disease (AD) pathogenesis and progression. Our recent results showed that overexpression of TREM2 inhibited inflammatory response in APP/PS1 mice and BV2 cells. Several studies indicated that TREM2 ameliorated tau hyperphosphorylation might be ascribed to the inhibition of neuroinflammation. However, the precise signaling pathways underlying the effect of TREM2 on tau pathology and neuronal apoptosis have not been fully elucidated. In the present study, upregulation of TREM2 significantly inhibited tau hyperphosphorylation at Ser199, Ser396, and Thr205, respectively, as well as prevented neuronal loss and apoptosis. We also found that upregulation of TREM2 alleviated behavioral deficits and improved the spatial cognitive ability of APP/PS1 mice. Further study revealed that TREM2 could activate phosphatidylinositol 3-kinase/protein kinase B (PI3K/Akt) signaling pathway, resulting in an inhibitory effect on glycogen synthase kinase-3ß (GSK-3ß), which is a major kinase responsible for tau hyperphosphorylation in AD. In line with in vivo findings, TREM2-overexpressing BV2 microglia following ß-amyloid (Aß) stimulation led to a significant increase in the phosphorylation of PI3K, Akt, and GSK-3ß, accompanied by a decrease in tau hyperphosphorylation and apoptosis in co-cultured SH-SY5Y cells. Furthermore, LY294002, a specific PI3K inhibitor, was observed to abolish the beneficial effects of TREM2 on tau hyperphosphorylation, neuronal apoptosis, and spatial cognitive impairments in vivo and in vitro. Thus, our findings indicated that TREM2 inhibits tau hyperphosphorylation and neuronal apoptosis, at least in part, by the activation of the PI3K/Akt/GSK-3ß signaling pathway. Taken together, the above results allow us to better understand how TREM2 protects against tau pathology and suggest that upregulation of TREM2 may provide new ideas and therapeutic targets for AD.

Hopping Light Vat Photopolymerization for Multiscale Fabrication.

3D objects with features spanning from microscale to macroscale have various applications. However, the fabrication of such objects presents challenges to additive manufacturing (AM) due to the tradeoffs among manufacturable feature resolution, maximum build area, and printing speed. This paper presents a projection-based AM process called hopping light vat photopolymerization (HL-VPP) to address this critical barrier. The key idea of HL-VPP is to synchronize linear scanning projection with a galvo mirror's rotation. The projector moves continuously at a constant speed while periodically rotating a one-axis galvo mirror to compensate for the projector's linear movement so synchronized hopping motion can be achieved. By this means, HL-VPP can simultaneously achieve large-area (over 200 mm), fast-speed (scanning speed of 13.5 mm s-1 ), and high-resolution (10 µm pixel size) fabrication. The distinguishing characteristic of HL-VPP is that it allows for hundreds of times lower refresh rates without motion blur. Thus, HL-VPP decouples the fabrication efficiency limit imposed by the refresh rate and will enable super-fast curing in the future. This work will significantly advance VPP's use in applications that require macroscale part size with microscale features. The process has been verified by fabricating multiple multiscale objects, including microgrids and biomimetic structures.

Electrocatalysis and electroanalysis of nickel, its oxides, hydroxides and oxyhydroxides toward small molecules.

The electrocatalysis toward small molecules, especially small organic compounds, is of importance in a variety of areas. Nickel based materials such as nickel, its oxides, hydroxides as well as oxyhydroxides exhibit excellent electrocatalysis performances toward many small molecules, which are widely used for fuel cells, energy storage, organic synthesis, wastewater treatment, and electrochemical sensors for pharmaceutical, medical, food or environmental analysis. Their electrocatalytic mechanisms are proposed from three aspects such as Ni(OH)2/NiOOH mediated electrolysis, direct electrocatalysis of Ni(OH)2 or NiOOH. Under exposure to air or aqueous solution, two distinct layers form on the Ni surface with a Ni hydroxide layer at the air-oxide interface and an oxide layer between the metal substrate and the outer hydroxide layer. The transformation from nickel or its oxides to hydroxides or oxyhydroxides could be further speeded up in the strong alkaline solution under the cyclic scanning at relatively high positive potential. The redox transition between Ni(OH)2 and NiOOH is also contributed to the electrocatalytic oxidation of Ni and its oxides toward small molecules in alkaline media. In addition, nickel based materials or nanomaterials, their preparations and applications are also overviewed here.