Oxidase‐Like Fe‐N‐C Single‐Atom Nanozymes for the Detection of Acetylcholinesterase Activity

Single‐atom catalysts (SACs) have attracted extensive attention in the catalysis field because of their remarkable catalytic activity, gratifying stability, excellent selectivity, and 100% atom utilization. With atomically dispersed metal active sites, Fe‐N‐C SACs can mimic oxidase by activating O₂ into reactive oxygen species, O₂^?? radicals. Taking advantages of this property, single‐atom nanozymes (SAzymes) can become a great impetus to develop novel biosensors. Herein, the performance of Fe‐N‐C SACs as oxidase‐like nanozymes is explored. Besides, the Fe‐N‐C SAzymes are applied in biosensor areas to evaluate the activity of acetylcholinesterase based on the inhibition toward nanozyme activity by thiols. Moreover, this SAzymes‐based biosensor is further used for monitoring the amounts of organophosphorus compounds.     

聚偏氟乙烯膜表面丙烯酸接枝改性研究

采用自由基接枝聚合反应制备了丙烯酸改性的聚偏氟乙烯膜,研究了单体浓度对接枝率的影响,测定了改性后样品的红外光谱、表面接触角、水通量、蛋白吸附等.结果表明,通过自由基接枝聚合,丙烯酸接枝到膜的表面,明显提高膜的亲水性.接枝后膜的水通量也非常明显下降,特别是在高丙烯酸浓度下.改性的膜的通量对溶液的pH值有明确的响应关系,表明接枝链在水中的溶胀对膜的性能有显著的影响.蛋白吸附实验表明,改性后的膜相比未改性膜有较高的吸附量,而且在酸性情况下,膜的吸附量较大,这主要与丙烯酸和蛋白质之间的相互作用有关.     

壳聚糖静电吸附羧基磷酰胆碱聚合物的研究

采用饥饿法聚合合成了3种不同配比的甲基丙烯酰氧乙基磷酰胆碱-甲基丙烯酸二元共聚物(poly(MPC-co-MA),PMA),并将其静电吸附在壳聚糖表面(CS-PMA)。通过动态接触角(DCA)对影响静电吸附改性的盐及聚合物组成因素进行研究。用X-射线光电子能谱(XPS)、原子力显微镜(AFM)对改性壳聚糖膜的表面元素组成、形貌进行表征,并通过血小板黏附实验对其抗凝血性能进行评价。结果表明,这种利用静电吸附的方式将磷酰胆碱聚合物吸附在壳聚糖表面,可获得具有仿细胞外层膜结构的涂层表面。与壳聚糖相比,改性后壳聚糖可以显著降低对血小板的黏附,抗凝血性能显著提高。该研究为构建仿细胞外层膜结构改善材料血液相容性提供了一种简单、便捷的方法。     

Single Iron Site Nanozyme for Ultrasensitive Glucose Detection

Nanomaterials with enzyme‐mimicking characteristics have engaged great awareness in various fields owing to their comparative low cost, high stability, and large‐scale preparation. However, the wide application of nanozymes is seriously restricted by the relatively low catalytic activity and poor specificity, primarily because of the inhomogeneous catalytic sites and unclear catalytic mechanisms. Herein, a support‐sacrificed strategy is demonstrated to prepare a single iron site nanozyme (Fe SSN) dispersed on the porous N‐doped carbon. With well‐defined coordination structure and high density of active sites, the Fe SSN performs prominent peroxidase‐like activity by efficiently activating H₂O₂ into hydroxyl radical (?OH) species. Furthermore, the Fe SSN is applied in colorimetric detection of glucose through a multienzyme biocatalytic cascade platform. Moreover, a low‐cost integrated agarose‐based hydrogel colorimetric biosensor is designed and successfully achieves the visualization evaluation and quantitative detection of glucose. This work expands the application of single‐site catalysts in the fields of nanozyme‐based biosensors and personal biomedical diagnosis.     

Surface modification with lasers

Laser-induced processing has been widely exploited in the microelectronics industry, to produce deposits with well-controlled chemical composition, feature size, and morphology. A brief survey of the most commonly used techniques for laser patterning of materials on surfaces is presented. The issues which are key to continued progress in the field of surface modification with lasers are examined, including laser heating of surfaces, the role of mass transport in the kinetics of deposit growth, the study of the surface reactions involved in laserinduced processes, and some aspects of materials properties which are important in surface modification techniques.     

含氟高分子生物材料的表面改性研究进展

含氟高分子材料因具有优异的稳定性和物理机械性能而成为目前研究和应用广泛的医用生物材料,但是,生物相容性的不足影响和限制了其作为体内长期植入材料的应用。因此,提高含氟高分子材料的生物相容性,尤其是通过表面改性的方法提高其生物相容性是一项有意义的研究课题。分别从改性手段和改性物质两方面综述了近年来国内外含氟高分子生物材料表面改性的研究发展。     

Tailoring the Surface and Composition of Nanozymes for Enhanced Bacterial Binding and Antibacterial Activity

With the advantages of diverse structures, tunable enzymatic activity, and high stability, nanozymes are widely used in medicine, chemistry, food, environment, and other fields. As an alternative to traditional antibiotics, nanozymes attract more and more attention from the scientific researchers in recent years. Developing nanozymes-based antibacterial materials opens up a new avenue for the bacterial disinfection and sterilization. In this review, the classification of nanozymes and their antibacterial mechanisms are discussed. The surface and composition of nanozymes are critical for the antibacterial efficacy, which can be tailored to enhance both the bacterial binding and the antibacterial activity. On the one hand, the surface modification of nanozymes enables binding and targeting of bacteria that improves the antibacterial performance of nanozymes including the biochemical recognition, the surface charge, and the surface topography. On the other hand, the composition of nanozymes can be modulated to achieve enhanced antibacterial performance including the single nanozyme-mediated synergistic and multiple nanozymes-mediated cascade catalytic antibacterial applications. In addition, the current challenges and future prospects of tailoring nanozymes for antibacterial applications are discussed. This review can provide insights into the design of future nanozymes-based materials for the antibacterial treatments.     

Surface modification by electron beams

An areal heat source can be generated by the line-shaped, high frequency scanning of an electron probe. Its use for tasks in the thermal modification of surfaces allows for an advantageous separation of the heating and cooling fronts. Moreover, the use of an elliptic distortion of the focal spot results in an enhanced throughput for penetration depths that greatly exceed the electron range. The application of this technique is explained by way of examples taken from the fields of microelectronics and the metalworking industries. Various aspects concerning the use of laser beams and electron beams for thermal surface modification are discussed.     

纳米ATO粉体的表面改性研究

采用偶联剂对纳米ATO(氧化锡锑)粉体进行表面改性,综合考察了偶联剂的品种与用量、反应时间及反应温度对表面改性效果的影响,从而确定最佳表面改性条件.利用红外光谱(FTIR)、热重分析(TGA)以及光吸收率等表征手段来研究表面改性的效果及分散状况.结果表明,纳米ATO粉体表面改性的最佳条件为:选用硅烷偶联剂KH570,添加量为2份,反应水浴温度为80℃,反应5h.     

Surface modification of micromachined silicon filters

Uniform and ultrathin coatings are needed on the surface of micromachined silicon filters in order to manipulate microfluid flow and minimize non specific protein adsorption. This work reports vapor phase deposition of nanometer thick alkylsilanes at atmospheric pressure using nitrogen as a carrier gas. The coatings were characterized with ellipsometry, SEM, AFM, contact angle goniometry, and zeta potential meter. The method is particularly advantageous when it is necessary to coat small channels in microdevices. Micromachined silicon filters were coated with different alkylsilanes and tested with nitrogen gas and a variety of liquids. Interesting flow rate reversal of water versus ethanol was observed when the minimum channel dimension shrank from 74 microns to 1.8 microns.     

Surface modification of superdrawn polyoxymethylene fibres

A new surface modification of superdrawn polyoxymethylene (POM) fibres, curing with resorcinol at mild temperatures, was developed to apply to rubber composites and the adhesion to the rubber matrix behaviour of modified fibres is discussed in terms of the interfacial miscibility between the fibre and adhesive surface layers. The modified fibre reached the maximum pull-out adhesion level in which a cohesive failure of the fibre occurs, resulting from the fact that the modified POM layer is spectroscopically close to the standard resorcinol-formaldehyde (RF) resin, thoroughly miscible and thermodynamically compatible with the resorcinol-formaldehyde-latex (RFL) adhesive.     

Surface modification of superdrawn polyoxymethylene fibres

The pull-out fracture of surface-modified superdrawn polyoxymethylene fibres embedded in rubber is discussed from a fractographical viewpoint. The morphologies of the pull-out fracture plane were very similar to those of the fracture surface in single lap-joint tests and the true pull-out stress coincided with the shear strength of a single lap-joint, indicating that the pull-out failure is strongly related to single lap-joint shear fracture.     

Surface modification of calcium metaphosphate fibers

-calcium metaphosphate fibers having high aspect ratios of 10–120 with diameters of 2–10 m show high strength and good biocompatibility. When the fibers are soaked in simulated body fluid at 37 °C, however, no calcium phosphate phase is newly formed on the fibers. In the present work, by treating the fibers at 70 °C with dilute NaOH aqueous solution, the surface phase was converted successfully into the orthophosphate phase that was in fine sizes and was adhered. After soaking the treated fibers in simulated body fluid at 37 °C for 30 days, a new calcium phosphate phase was precipitated. This was attributed to the surface phase modified using dilute NaOH. The treated fibers are expected to show bone-bonding ability, i.e. bioactivity. ©2000 Kluwer Academic Publishers     

基于纳米酶制备技术及用于四环素类抗生素的快速分析

本文系基于Fe_3O_4磁性纳米粒子建立一种新颖的生物传感器显色法用于高灵敏检测四环素(TCs)。实验显示四环素具有强烈的和Fe_3O_4络合的倾向从而抑制Fe_3O_4 MNPs-H_2O_2-TMB显色体系。利用水热法合成Fe_3O_4纳米酶,通过FT-IR、XRD、SEM、TEM等手段对Fe_3O_4纳米酶进行表征,并将该材料用于四环素类抗生素的快速检测。同时本文还优化了各种参数。在最佳条件下,方法定量限为0.035-0.043μg,回收率为90.9%～95.6%。