Hoilun Wong

Multichannel nerve guidance conduits (NGCs) have demonstrated superior efficacy in the regeneration of large nerve defects. Here, we present the incorporation of three synergistic guiding cues into a single multichannel hydrogel conduit: topographical guidance, a conductivity gradient, and a nerve growth factor (NGF) gradient. The aligned hydrogel conduit is fabricated through directional lyophilization of a graphene oxide (GO)/poly(vinyl alcohol) (PVA) solution. The conductivity gradient is achieved via the dopamine-induced reduction of GO, during which amino groups with a concentration gradient are simultaneously generated, facilitating the eventual formation of an NGF gradient. In vitro experiments validate the excellent guidance effect and promotion of neuritogenesis by the NGF-gradient/aligned PVA/reduced graphene oxide (rGO)/polydopamine (PDA)/heparin hydrogel conduit (denoted as NGF-AGHC) on PC12 neuronal cells. Furthermore, in vivo testing reveals that NGF-AGHC exhibits a stronger longitudinal attraction to axons and promotes remyelination. Additionally, functional recovery assessments, histological analyses, and morphological evaluations all indicate that NGF-AGHC significantly enhances peripheral nerve regeneration, with performance comparable to that of the autograft group. Altogether, through a straightforward preparation method integrating topographical guidance, conductivity gradients, and NGF gradients, our NGCs offer a promising approach to peripheral nerve repair.

With a high specific capacity and low electrochemical potentials, metal anode batteries that use lithium, sodium and zinc metal anodes, have gained great research interest in recent years, as a potential candidate for high-energy-density storage systems. However, the uncontainable dendrite growth during the repeated charging process, deteriorates the battery performance, reduces the battery life and more importantly, raises safety concerns. With their unique properties, two-dimensional (2D) materials, can be used to modify various components in metal batteries, eventually mitigating the dendrite growth, enhancing the cycling stability and rate capability, thus leading to safe and robust metal anodes. In this paper, we review the recent advances of 2D materials and summarize current research progress of using 2D materials in the applications of (i) anode design, (ii) separator engineering, and (iii) electrolyte modifications by guiding metal ion nucleation, increasing ion conductivity, homogenizing the electric field and ion flux, and enhancing the mechanical strength for safe metal anodes. The 2D material modifications provide the ultimate solution for obtaining dendrite-free metal anodes, realizes the high energy storage application, and indicates the importance of 2D materials development. Finally, in-depth understandings of subsequent metal growth are lacking due to research limitations, while more advanced characterizations are welcome for investigating the metal deposition mechanism. The more facile and simplified preparation of 2D materials possess great prospects in high energy density metal anode batteries, and thus fulfils the development of EVs.

We demonstrate the use of the machine learning (ML) tools to rapidly and accurately predict the electric field as a guide for designing core-shell Au-silica nanoparticles to enhance ¹O₂ sensitization and selectivity of organic synthesis. Based on the feature importance analysis, obtained from a deep neural network algorithm, we found a general and linear dependent descriptor (θ ∝ aD^0.25t^-1, where a, D, and t are the shape constant, size of metal nanoparticles, and distance from the metal surface) for the electric field around the core-shell plasmonic nanoparticle. Directed by the new descriptor, we synthesized gold-silica nanoparticles and validated their plasmonic intensity using scanning transmission electron microscopy-electron energy loss spectroscopy (STEM-EELS) mapping. The nanoparticles with θ = 0.40 demonstrate an ∼3-fold increase in the reaction rate of photooxygenation of anthracene and 4% increase in the selectivity of photooxygenation of dihydroartemisinic acid (DHAA), a long-standing goal in organic synthesis. In addition, the combination of ML and experimental investigations shows the synergetic effect of plasmonic enhancement and fluorescence quenching, leading to enhancement for ¹O₂ generation. Our results from time-dependent density functional theory (TD-DFT) calculations suggest that the presence of an electric field can favor intersystem crossing (ISC) of methylene blue to enhance ¹O₂ generation. The strategy reported here provides a data-driven catalyst preparation method that can significantly reduce experimental cost while paving the way for designing photocatalysts for organic drug synthesis.

Single-photon emitters (SPEs) in hexagonal boron nitride (hBN) are promising candidates for quantum light generation. Despite this, techniques to control the formation of hBN SPEs down to the monolayer limit are yet to be demonstrated. Recent experimental and theoretical investigations have suggested that the visible wavelength single-photon emitters in hBN originate from carbon-related defects. Here, we demonstrate a simple strategy for controlling SPE creation during the chemical vapor deposition growth of monolayer hBN via regulating surface carbon concentration. By increasing the surface carbon concentration during hBN growth, we observe increases in carbon doping levels by 2.4-fold for B–C bonds and 1.6-fold for N–C bonds. For the same samples, we observe an increase in the SPE density from 0.13 to 0.30 emitters/μm². Our simple method enables the reliable creation of hBN SPEs in monolayer samples for the first time, opening the door to advanced two-dimensional (2D) quantum state engineering.