Multicolor Photo‐Crosslinkable AIEgens toward Compact Nanodots for Subcellular Imaging and STED Nanoscopy

Aggregation induced emission (AIE) has attracted considerable interest for the development of fluorescence probes. However, controlling the bioconjugation and cellular labeling of AIE dots is a challenging problem. Here, this study reports a general approach for preparing small and bioconjugated AIE dots for specific labeling of cellular targets. The strategy is based on the synthesis of oxetane‐substituted AIEgens to generate compact and ultrastable AIE dots via photo‐crosslinking. A small amount of polymer enriched with oxetane groups is cocondensed with most of the AIEgens to functionalize the nanodot surface for subsequent streptavidin bioconjugation. Due to their small sizes, good stability, and surface functionalization, the cell‐surface markers and subcellular structures are specifically labeled by the AIE dot bioconjugates. Remarkably, stimulated emission depletion imaging with AIE dots is achieved for the first time, and the spatial resolution is significantly enhanced to ≈95 nm. This study provides a general approach for small functional molecules for preparing small sized and ultrastable nanodots.     

Mesoporous NiS2 Nanospheres Anode with Pseudocapacitance for High‐Rate and Long‐Life Sodium‐Ion Battery

It is of great importance to exploit electrode materials for sodium‐ion batteries (SIBs) with low cost, long life, and high‐rate capability. However, achieving quick charge and high power density is still a major challenge for most SIBs electrodes because of the sluggish sodiation kinetics. Herein, uniform and mesoporous NiS₂ nanospheres are synthesized via a facile one‐step polyvinylpyrrolidone assisted method. By controlling the voltage window, the mesoporous NiS₂ nanospheres present excellent electrochemical performance in SIBs. It delivers a high reversible specific capacity of 692 mA h g^?1. The NiS₂ anode also exhibits excellent high‐rate capability (253 mA h g^?1 at 5 A g^?1) and long‐term cycling performance (319 mA h g^?1 capacity remained even after 1000 cycles at 0.5 A g^?1). A dominant pseudocapacitance contribution is identified and verified by kinetics analysis. In addition, the amorphization and conversion reactions during the electrochemical process of the mesoporous NiS₂ nanospheres is also investigated by in situ X‐ray diffraction. The impressive electrochemical performance reveals that the NiS₂ offers great potential toward the development of next generation large scale energy storage.     

Application potential of bone marrow mesenchymal stem cell (BMSCs) based tissue-engineering for spinal cord defect repair in rat fetuses with spina bifida aperta

Spina bifida aperta are complex congenital malformations resulting from failure of fusion in the spinal neural tube during embryogenesis. Despite surgical repair of the defect, most patients who survive with spina bifida aperta have a multiple system handicap due to neuron deficiency of the defective spinal cord. Tissue engineering has emerged as a novel treatment for replacement of lost tissue. This study evaluated the prenatal surgical approach of transplanting a chitosan–gelatin scaffold seeded with bone marrow mesenchymal stem cells (BMSCs) in the healing the defective spinal cord of rat fetuses with retinoic acid induced spina bifida aperta. Scaffold characterisation revealed the porous structure, organic and amorphous content. This biomaterial promoted the adhesion, spreading and in vitro viability of the BMSCs. After transplantation of the scaffold combined with BMSCs, the defective region of spinal cord in rat fetuses with spina bifida aperta at E20 decreased obviously under stereomicroscopy, and the skin defect almost closed in many fetuses. The transplanted BMSCs in chitosan–gelatin scaffold survived, grew and expressed markers of neural stem cells and neurons in the defective spinal cord. In addition, the biomaterial presented high biocompatibility and slow biodegradation in vivo. In conclusion, prenatal transplantation of the scaffold combined with BMSCs could treat spinal cord defect in fetuses with spina bifida aperta by the regeneration of neurons and repairmen of defective region.     

氧化镧/聚丙烯防X射线复合纤维的制备及性能表征

先采用熔融纺丝方法制备了不同氧化镧含量的氧化镧/聚丙烯复合纤维,然后采用对二甲苯在相同处理时间(1 h)不同温度(105~109℃)下溶解复合纤维中的部分聚丙烯基体以提高纤维中氧化镧含量,并对处理过后的纤维进行扫描电镜、X射线屏蔽性能等测试。此外,采用硅烷偶联剂改性氧化镧,通过熔融纺丝法制备了表面活性氧化镧/聚丙烯复合纤维,并对其作了差示扫描量热分析、扫描电镜、力学测试等性能表征。实验结果表明,随未改性氧化镧添加量增加,纤维力学性能下降,玻璃化转变温度向低温方向移动,纤维热稳定提高;有机改性可改善氧化镧在聚丙烯中的分散,提高纤维的力学性能,纤维玻璃化转变温度较纯聚丙烯纤维升高;用对二甲苯在107℃处理1h所获取的复合纤维中氧化镧含量最高,X射线屏蔽性能最优。     

熔融沉积成型桌面3D打印机的基础几何误差分析

为了探讨熔融成型桌面打印机成型的基础几何尺寸精度,并为熔融成型桌面打印机的市场定位提供设计参考依据,设计了线纹、步距、间隙、孔径、台阶等典型几何特征的三维模型,并采用选用PLA材料对这些基础几何特征进行熔融沉积成型。实验分别在自组装FDM 3D打印机、厦门螺壳电子科技有限公司、浙江闪铸三维科技有限公司的标准打印机上实施。最后基于对FDM成型的标准版基础几何特征尺寸精度能力的测试,初步提出一些适用于FDM打印品的质量评价方法以及标准测试样板的设计规则,对3D打印机的市场定位以及建立相关标准提供第三方检验测试手段。