Structural and Electronic Properties of Two-Dimensional Materials: A Machine-Learning-Guided Prediction

The growing number of studies and interest in two-dimensional (2D) materials has not yet resulted in a wide range of material applications. This is a result of difficulties in getting the properties, which are often determined through numerical experiments or through first-principles predictions, both of which require lots of time and resources. Here we provide a general machine learning (ML) model that works incredibly well as a predictor for a variety of electronic and structural properties such as band gap, fermi level, work function, total energy and area of unit cell for a wide range of 2D materials derived from the Computational 2D Materials Database (C2DB). Our predicted model for classification of samples works extraordinarily well and gives an accuracy of around 99 %. We are able to successfully decrease the number of studied features by employing a strict permutation-based feature selection method along with the sure independence screening and sparsifying operator (SISSO), which further supports the design recommendations for the identification of novel 2D materials with the desired properties.     

新型含悬挂羧基聚乳酸的制备及其血液相容性和细胞粘附性

制备了乳酸-苹果酸共聚物(PLMA), 并在前期工作的基础上制备了悬挂羧基聚乳酸(PLMACA), 考察了手臂长度及端功能基团对改善聚乳酸的血液相容性及细胞粘附性的影响. 结果表明, PLMACA同时具有良好的血液相容性和细胞亲和性, 极有可能成为新一代血管(修复)材料.     

Carboxymethylchitosan/Poly(amidoamine) Dendrimer Nanoparticles in Central Nervous Systems‐Regenerative Medicine: Effects on Neuron/Glial Cell Viability and Internalization Efficiency

The applicability of CMCht/PAMAM dendrimer nanoparticles for CNS applications was investigated. AFM and TEM observations revealed that the nanoparticles possessed a nanosphere‐like shape with a size from 22.0 to 30.7 nm. The nanoparticles could be bound to fluorescent‐probe FITC for tracing purposes. Post‐natal hippocampal neurons and cortical glial cells were both able to internalize the FITC‐labeled CMCht/PAMAM dendrimer nanoparticles with high efficiency. The percentage of positive cells internalizing the nanoparticles varied, reaching a peak after 48 h of incubation. Further experiments for periods up to 7 d revealed that the periodical addition of FITC‐labelled CMCht/PAMAM dendrimer nanoparticles was needed to maintain the overall percentage of cells internalizing them. Finally, it was also observed that cell viability was not significantly affected by the incubation of dendrimer nanoparticles.

     

Recent Advances in Surface Modifications of Elemental Two-Dimensional Materials: Structures,Properties, and Applications

The advent of graphene opens up the research into two-dimensional (2D) materials, which are considered revolutionary materials. Due to its unique geometric structure, graphene exhibits a series of exotic physical and chemical properties. In addition, single-element-based 2D materials (Xenes) have garnered tremendous interest. At present, 16 kinds of Xenes (silicene, borophene, germanene, phosphorene, tellurene, etc.) have been explored, mainly distributed in the third, fourth, fifth, and sixth main groups. The current methods to prepare monolayers or few-layer 2D materials include epitaxy growth, mechanical exfoliation, and liquid phase exfoliation. Although two Xenes (aluminene and indiene) have not been synthesized due to the limitations of synthetic methods and the stability of Xenes, other Xenes have been successfully created via elaborate artificial design and synthesis. Focusing on elemental 2D materials, this review mainly summarizes the recently reported work about tuning the electronic, optical, mechanical, and chemical properties of Xenes via surface modifications, achieved using controllable approaches (doping, adsorption, strain, intercalation, phase transition, etc.) to broaden their applications in various fields, including spintronics, electronics, optoelectronics, superconducting, photovoltaics, sensors, catalysis, and biomedicines. These advances in the surface modification of Xenes have laid a theoretical and experimental foundation for the development of 2D materials and their practical applications in diverse fields.     

Enhanced Antioxidant,Hyaluronidase, and Collagenase Inhibitory Activities of Glutinous Rice Husk Extract by Aqueous Enzymatic Extraction

In this research, we aimed to compare the biological activities related to cosmeceutical applications of glutinous rice husk extracted by aqueous enzymatic extraction (AEE) and conventional solvent extraction. Cellulase enzymes were used to assist the extraction process. The vanillic and ferulic acid contents of each extract were investigated by high-performance liquid chromatography, and their antioxidant and anti-aging activities were investigated by spectrophotometric methods. The irritation effects of each extract were investigated by the hen’s egg test on chorioallantoic membrane. The rice husk extract from AEE using 0.5% w/w of cellulase (CE0.5) contained the significantly highest content of vanillic and ferulic acid (p < 0.05), which were responsible for its biological activities. CE0.5 was the most potent antioxidant via radical scavenging activities, and possessed the most potent anti-skin wrinkle effect via collagenase inhibition. Aside from the superior biological activities, the rice husk extracts from AEE were safer than those from solvent extraction, even when 95% v/v ethanol was used. Therefore, AEE is suggested as a green extraction method that can be used instead of the traditional solvent extraction technique given its higher yield and high quality of bioactive compounds. Additionally, CE0.5 is proposed as a potential source of natural antioxidants and anti-aging properties for further development of anti-wrinkle products.     

4-巯基苯甲酸功能化纳米金粒子固定葡萄糖氧化酶/漆酶基燃料电池性能

以4-巯基苯甲酸修饰纳米金粒子作为固酶载体和导电基体构建了新型纳米结构固酶葡萄糖/O₂燃料电池,其制备简单,长期使用性能稳定。利用纳米金粒子通过表面修饰基团和酶分子活性中心附近疏水结合位之间的相互作用固定葡萄糖氧化酶(GO_x)和漆酶(Lac)分子,分别制备了固酶阳极-4-巯基苯甲酸功能化纳米金粒子固定葡萄糖氧化酶修饰金盘电极GO_x/4-MBA@GNP/Au和固酶阴极-4-巯基苯甲酸功能化纳米金粒子固定漆酶修饰金盘电极Lac/4-MBA@GNP/Au。电化学实验结果表明,两种电极在不引入任何外加电子中介的条件下,均可以实现酶活性中心-纳米金粒子之间的直接电子迁移,而且具有较快的催化反应能力(固酶阳极和阴极的转化速率分别为1.3和0.5 s^-1;催化葡萄糖氧化和氧气还原的起始电位分别为-0.23和0.76 V)。评估了固酶阳极和阴极组装成的纳米结构固酶葡萄糖/O₂燃料电池的能量输出性能。该燃料电池在没有Nafion薄膜和阳极无N₂气保护下,开路电压和最大输出能量密度分别可达0.56 V和760.0 μW/cm²,使用一周后输出能量密度仍然可以达到最初值的~88%。进一步测试结果显示,该燃料电池呈现出与游离漆酶类似的pH依赖关系和热稳定性,这些实验结果均暗示:影响整个酶燃料电池性能的关键在于漆酶基阴极催化氧还原的过程。此外,这种燃料电池的性能虽然受到共存干扰物抗坏血酸的影响,但在人类血清中测试结果显示其仍然具有较高的输出能量密度(132.0 μW/cm²,开路电压0.40 V)。本文研究结果给出了设计高性能葡萄糖/O₂燃料电池的新思路,同时也为研究固酶燃料电池的构效关系提供了实验依据和有价值的启示。     

Hyaluronan/Collagen Hydrogels with Sulfated Hyaluronan for Improved Repair of Vascularized Tissue Tune the Binding of Proteins and Promote Endothelial Cell Growth

Innovative biomaterial‐based concepts are required to improve wound healing of damaged vascularized tissues especially in elderly multimorbid patients. To develop functional hydrogels as 3D cellular microenvironments and as carrier or scavenging systems, e.g., for mediator proteins or proinflammatory factors, collagen fibrils are embedded into a network of photo‐crosslinked acrylated hyaluronan (HA), chondroitin sulfate (CS), or sulfated HA (sHA). After lyophilization, the gels show a porous structure and an improved stability against degradation via hyaluronidase. Gels with CS and sHA bind significantly more lysozyme than HA/collagen gels and retard its release. The proliferation and metabolic activity of endothelial cells are significantly increased on sHA gels compared to CS‐ or only HA‐containing hydrogels. These findings highlight the potential of HA/collagen hydrogels with sulfated glycosaminoglycans to tune the protein binding and release behavior and to directly modulate cellular response. This can be easily translated into biomimetic biomaterials with defined properties to stimulate wound healing.     

Determination of Commercial Animal and Vegetable Milks’ Lipid Profile and Its Correlation with Cell Viability and Antioxidant Activity on Human Intestinal Caco-2 Cells

Lipids from milk are important nutritional components, although their health effects, especially for animal milks, are still questioned. Four types of commercial milks, two semi-skimmed animal milks (bovine and goat) and two vegetable ones (soy and rice), along with their total and free lipid fractions recovered by sequential centrifugation or by ethyl acetate extraction, respectively, have been analyzed. A higher antioxidant ability, reported as Trolox equivalent antioxidant capacity, was found for all raw milks compared to that of rice. This trend was confirmed, except for soy milk, as ROS reduction in Caco-2 cells. The free lipid fraction was shown to have the highest antioxidant potential in both chemical and biological tests. Moreover, goat and soy raw milks positively regulated Caco-2 cell viability after an inflammatory stimulus. This effect was lost when their total lipid fraction was tested. Finally, only the free lipid fraction from rice milk preserved the Caco-2 viability after LPS stimulation. Our data demonstrated that the lipid profile of each milk, characterized by GC-MS analysis, could contribute to dictate its biological effects, and, although additional in vitro and in vivo studies are needed, they could support the literature re-evaluating the health effects of animal-based versus plant-based milks in the intestinal cellular model.