Tough and Self‐Recoverable Thin Hydrogel Membranes for Biological Applications

Tough and self‐recoverable hydrogel membranes with micrometer‐scale thickness are promising for biomedical applications, which, however, rarely be realized due to the intrinsic brittleness of hydrogels. In this work, for the first time, by combing noncovalent DN strategy and spin‐coating method, we successfully fabricated thin (thickness: 5–100 µm), yet tough (work of extension at fracture: 10⁵–10⁷ J m^?3) and 100% self‐recoverable hydrogel membranes with high water content (62–97 wt%) in large size (≈100 cm²). Amphiphilic triblock copolymers, which form physical gels by self‐assembly, were used for the first network. Linear polymers that physically associate with the hydrophilic midblocks of the first network, were chosen for the second network. The inter‐network associations serve as reversible sacrificial bonds that impart toughness and self‐recovery properties on the hydrogel membranes. The excellent mechanical properties of these obtained tough and thin gel membranes are comparable, or even superior to many biological membranes. The in vitro and in vivo tests show that these hydrogel membranes are biocompatible, and postoperative nonadhesive to neighboring organs. The excellent mechanical and biocompatible properties make these thin hydrogel membranes potentially suitable for use as biological or postoperative antiadhesive membranes.     

超快激光与生物含水组织相互作用

研究了超快脉冲激光与生物组织相互作用的机理 ,建立了生物软组织中激光诱导光学击穿模型 ;结果表明 ,对于纳秒或亚纳秒脉冲激光 ,强吸收介质的热电子发射对电子雪崩电离过程有很大影响 ,等离子体光学击穿阈值随生物组织吸收的增加而降低 ;在激光脉宽为亚皮秒量级时 ,多光子电离成为光学击穿的主要机制 ,介质的击穿阈值几乎与线性吸收系数无关。在达到光学击穿阈值时 ,激光能量沉积在厚度约 1μm的薄层之内 ;随着激光能量显著超过击穿阈值 ,有效的激光透过深度减小。     

炮口冲击波的生物效应研究

初步探讨了炮口冲击波的超压场分布和生物效应 .实验结果表明炮口冲击波有二次激波形成 ,超压峰值以炮口前方 1 m附近最高 ;而炮尾处仅有一次激波形成 ,超压峰值较低 .生物效应主要为听器、肺、上呼吸道损伤 ,有时伴有胃肠道损伤 ,损伤程度与炮口冲击波超压明显有关 .二次焰可引起动物潦毛 .该结果为冲击波损伤的量效关系积累了基础数据 ,对火炮设计有一定的指导意义 .     

监测吡虫啉杀虫剂的光纤荧光光谱仪研究

根据吡虫啉农药在紫外光的照射下能发射荧光的机理,研制了一种监测吡虫啉的荧光光纤光谱仪。该仪器采用氙灯作为激发光源,结合光纤传感和CCD技术,实现了对吡虫啉杀虫剂的快速测定。同时,该仪器还可用于河水和地下水中痕量吡虫啉的测量,其回收率接近100％。     

管腐蚀法制作纳米光纤探针

根据优质探针的理论模型,利用管腐蚀法制作了可用于光纤生物传感器的纳米光纤探针,该制作方法操作方便,成本低廉,易于批量生产,且受环境的影响较小,制作的光纤探针具有较高的重复率。所获探针锥径小于50nm,锥角为45°。最后讨论了在管腐蚀实验中不良因素对光纤探针形貌的影响。     

Multifunctional Silver‐Exchanged Zeolite Micromotors for Catalytic Detoxification of Chemical and Biological Threats

Multifunctional reactive‐zeolite‐based micromotors have been developed and characterized toward effective and rapid elimination of chemical and biological threats. The incorporation of silver ions (Ag⁺) into aluminosilicate zeolite framework imparts several attractive functions, including strong binding to chemical warfare agents (CWA) followed by effective degradation, and enhanced antibacterial activity. The new zeolite‐micromotors protocol thus combines the remarkable adsorption capacity of zeolites and the efficient catalytic properties of the reactive Ag⁺ ions with the autonomous movement of the zeolite micromotors for an accelerated detoxification of CWA. Furthermore, the high antibacterial activity of Ag⁺ along with the rapid micromotor movement enhances the contact between bacteria and reactive Ag⁺, leading to a powerful “on‐the‐fly” bacteria killing capacity. These attractive adsorptive/catalytic features of the self‐propelled zeolite micromotors eliminate secondary environmental contamination compared to adsorptive micromotors. The distinct cubic geometry of the zeolite micromotors leads to enhanced bubble generation and faster movement, in unique movement trajectories, which increases the fluid convection and highly efficient detoxification of CWA and killing of bacteria. The attractive capabilities of these zeolite micromotors will pave the way for their diverse applications in defense, environmental and biomedical applications in more economical and sustainable manner.     

PbS/CdS/ZnS Quantum Dots: A Multifunctional Platform for In Vivo Near‐Infrared Low‐Dose Fluorescence Imaging

Over the past decade, near‐infrared (NIR)‐emitting nanoparticles have increasingly been investigated in biomedical research for use as fluorescent imaging probes. Here, high‐quality water‐dispersible core/shell/shell PbS/CdS/ZnS quantum dots (hereafter QDs) as NIR imaging probes fabricated through a rapid, cost‐effective microwave‐assisted cation exchange procedure are reported. These QDs have proven to be water dispersible, stable, and are expected to be nontoxic, resulting from the growth of an outer ZnS shell and the simultaneous surface functionalization with mercaptopropionic acid ligands. Care is taken to design the emission wavelength of the QDs probe lying within the second biological window (1000–1350 nm), which leads to higher penetration depths because of the low extinction coefficient of biological tissues in this spectral range. Furthermore, their intense fluorescence emission enables to follow the real‐time evolution of QD biodistribution among different organs of living mice, after low‐dose intravenous administration. In this paper, QD platform has proven to be capable (ex vivo and in vitro) of high‐resolution thermal sensing in the physiological temperature range. The investigation, together with the lack of noticeable toxicity from these PbS/CdS/ZnS QDs after preliminary studies, paves the way for their use as outstanding multifunctional probes both for in vitro and in vivo applications in biomedicine.     

指纹识别系统的一种低功耗实现方法与应用

提出了一种指纹识别系统的低功耗设计方法,采用基于双控制核心的系统构架,将指纹识别功能和外设控制功能独立分开的设计,以ARM核心的ML67Q5250实现指纹的采集、处理、识别和匹配,以16位的超低功耗单片机MSP430F149控制外围设备实现指纹识别系统的具体应用,解决了指纹识别系统的高效率和低功耗的问题.     

Structural Orientation and Anisotropy in Biological Materials: Functional Designs and Mechanics

Biological materials exhibit anisotropic characteristics because of the anisometric nature of their constituents and their preferred alignment within interfacial matrices. The regulation of structural orientations is the basis for material designs in nature and may offer inspiration for man‐made materials. Here, how structural orientation and anisotropy are designed into biological materials to achieve diverse functionalities is revisited. The orientation dependencies of differing mechanical properties are introduced based on a 2D composite model with wood and bone as examples; as such, anisotropic architectures and their roles in property optimization in biological systems are elucidated. Biological structural orientations are designed to achieve extrinsic toughening via complicated cracking paths, robust and releasable adhesion from anisotropic contact, programmable dynamic response by controlled expansion, enhanced contact damage resistance from varying orientations, and simultaneous optimization of multiple properties by adaptive structural reorientation. The underlying mechanics and material‐design principles that could be reproduced in man‐made systems are highlighted. Finally, the potential and challenges in developing a better understanding to implement such natural designs of structural orientation and anisotropy are discussed in light of current advances. The translation of these biological design principles can promote the creation of new synthetic materials with unprecedented properties and functionalities.     

表面增强拉曼光谱技术在环境污染物检测中的应用

表面增强拉曼散射(SERS)光谱具有高灵敏性及高选择性,它已被用于科学研究及生产实践的多个领域。本文阐述了近几年来SERS技术在检测重金属离子、多环芳烃、微生物、农药等环境污染物中的发展状况,并分析了该技术在这些应用领域的优点与不足。最后,预测了SERS的发展趋势。