Activity Regulating Strategies of Nanozymes for Biomedical Applications

On accounts of the advantages of inherent high stability, ease of preparation and superior catalytic activities, nanozymes have attracted tremendous potential in diverse biomedical applications as alternatives to natural enzymes. Optimizing the activity of nanozymes is significant for widening and boosting the applications into practical level. As the research of the catalytic activity regulation strategies of nanozymes is boosting, it is essential to timely review, summarize, and analyze the advances in structure–activity relationships for further inspiring ingenious research into this prosperous area. Herein, the activity regulation methods of nanozymes in the recent 5 years are systematically summarized, including size and morphology, doping, vacancy, surface modification, and hybridization, followed by a discussion of the latest biomedical applications consisting of biosensing, antibacterial, and tumor therapy. Finally, the challenges and opportunities in this rapidly developing field is presented for inspiring more and more research into this infant yet promising area.     

Detection of Glucose Based on Noble Metal Nanozymes: Mechanism,Activity Regulation,and Enantioselective Recognition

Glucose monitoring is essential to evaluate the degree of glucose metabolism disorders. The enzymatic determination has been the most widely used method in glucose detection because of its high efficiency, accuracy, and sensitivity. Noble metal nanomaterials (NMs, i.e., Au, Ag, Pt, and Pd), inheriting their excellent electronic, optical, and enzyme-like properties, are classified as noble metal nanozymes (NMNZs). As the NMNZs are often involved in two series of reactions, the oxidation of glucose and the chromogenic reaction of peroxide, here the chemical mechanism by employing NMNZs with glucose oxidase (GOx) and peroxidase (POD) mimicking activities is briefly summarized first. Subsequently, the regulation strategies of the GOx-like, POD-like and tandem enzyme-like activities of NMNZs are presented in detail, including the materials, size, morphology, composition, and the reaction condition of the representative NMs. In addition, in order to further mimic the enantioselectivity of enzyme, the design of NMNZs with enantioselective recognition of d -glucose and l -glucose by using different chiral compounds (DNA, amino acids, and cyclodextrins) and molecular imprinting is further described in this review. Finally, the feasible solutions to the existing challenges and a vision for future development possibilities are discussed.     

抗菌陶瓷的研究现状及展望

概述了抗菌陶瓷中使用的抗菌剂及其抗菌机理,以及国内外抗菌陶瓷的研究现状.介绍了目前普遍采用的一些评价抗菌性能的方法.就目前抗菌陶瓷发展中存在的问题提出了解决办法,并对抗菌陶瓷的发展进行了展望.     

Antibacterial Activity of Graphdiyne and Graphdiyne Oxide

From manufacture to disposal, the interaction of graphdiyne based nanomaterials with living organisms is inevitable and crucial. However, the cytotoxic properties of this novel carbon nanomaterial are rarely investigated, and the mechanisms behind their cytotoxicity are totally unknown. In this study, the antibacterial activity of graphdiyne (GDY) and graphdiyne oxide (GDYO) is reported. GDY is capable of inhibiting broad‐spectrum bacterial growth while exerting moderate cytotoxicity on mammalian cells. In comparison, GDYO exhibits lower antibacterial activity than that of GDY. Then an alterable, synergetic antibacterial mechanism of GDY, involving wrapping bacterial membrane, membrane insertion and disruption, and reactive oxygen species generation is demonstrated, while the differential gene expression analysis indicates that GDY could only alter the bacterial metabolism slightly and the oxidative stress route may be a minor bactericidal factor. The investigation of the antibacterial behaviors of GDY based nanomaterials may provide useful guidelines for the future design and application of this novel molecular allotrope of carbon.     

Synthesis of Amorphous/Crystalline Hetero-Phase Nanozymes With Peroxidase-Like Activity by Coordination-Driven Self-Assembly for Biosensors

Nanozymes and amorphous nanomaterials attract great attention owing to their extraordinary properties. However, the requirements for special synthesis conditions become the bottleneck of their development. Herein, a new strategy involving the DNA-based coordination-driven self-assembly is reported for the synthesis of a novel amorphous/crystalline hetero-phase nanozyme (Fe-DNA). For the synthesis of both nanozymes and amorphous materials, this strategy is simple and controllable, avoiding the traditionally employed harsh conditions. Benefitting from the amorphous structure and the superior physicochemical properties, the synthesized Fe-DNA nanozyme is subsequently found to exhibit a smaller Michaelis constant value for hydrogen peroxide (H₂O₂) (0.81 mm ) than that of horseradish peroxidase (HRP) (3.70 mm ), demonstrating the stronger affinity of the Fe-DNA nanozyme toward H₂O₂. The Fe-DNA nanozyme also shows significant peroxidase-like activity but only negligible oxidase-like activity, a characteristic which releases the corresponding assay system from oxygen interference, thereby improving the performance of the nanozyme-based sensing platform. In addition, compared with other nanozymes, the novel Fe-DNA nanozyme is degradable via phosphate; thus, mitigating potential environmental threat. This work provides novel amorphous/crystalline hetero-phase nanozymes and opens a new avenue for the design of amorphous nanomaterials and nanozymes.     

抗菌材料发展和现状

简要介绍了抗菌材料的分类、抗菌原理及其应用,综述了抗菌不锈钢发展现状及其特点、抗菌原理和应用情况,并对抗菌材料研究进行了展望.     

苯并异噻唑啉酮接枝丙烯酸锌树脂的合成及抑菌性能

借鉴有机锡侧链防污结构,设计并合成具有类似有机锡树脂侧链丁基锡防污结构的苯并异噻唑啉酮接枝丙烯酸锌树脂,主要通过顺丁烯二酸酐对苯并异噻唑啉酮改性,赋予其羧酸基团,再与丙烯酸树脂接枝获得苯并异噻唑啉酮接枝丙烯酸锌树脂,赋予其侧链防污结构链段。通过核磁共振氢谱、傅立叶红外光谱表征手段鉴定其结构,并结合假交替单胞菌与创伤弧菌两种海洋细菌验证其抑菌性能。试验结果表明苯并异噻唑啉酮接枝丙烯酸锌树脂对海洋细菌具有优异的抑菌效果。     

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.     

GO-nAg复合材料的制备及其抗菌性能研究

采用化学还原法在氧化石墨烯(GO)表面负载纳米银(nAg),制备纳米银-氧化石墨烯复合抗菌材料(GO-nAg)。透射电子显微镜(TEM)和X射线能量色散谱(EDS)表征结果表明,纳米银成功地负载在GO表面,纳米银分散良好。以大肠杆菌为目标细菌,对GO-nAg、纳米银以及GO的抗菌活性进行比较,实验结果表明,GO-nAg未表现出很强的抗菌性,且与纳米银抗菌效果基本一致,而GO抗菌效果更好。     

铜负载二氧化钛复合材料的制备及其抗菌性能

以二氧化钛纳米颗粒和硫酸铜溶液为原料,在紫外线灯的照射下进行铜负载二氧化钛纳米带复合材料制备,采用扫描电子显微镜(SEM)、X-射线能谱仪(EDS)、X-射线衍射仪(XRD)、抑菌圈法、细菌比浊法等分析技术研究了所制备负载纳米带复合材料的微观结构及抗菌性能。结果表明,纳米二氧化钛粒子在水热条件下可生长成纳米带,铜均匀负载在纳米带上,从而制备出铜负载二氧化钛纳米带复合材料,负载程度可以通过更改照射时间、硫酸铜浓度等条件进行微调;该负载纳米带复合材料对革兰氏菌有很好的抗菌性能,且负载程度越高,产物抗菌性能越大。     

氨基功能化抗菌碳量子点的制备及抗菌性能研究

目的 以精胺、多巴胺为原材料合成氨基功能化抗菌碳量子点，为进一步将其应用于食源性致病菌消除领域提供参考。方法 利用精胺、多巴胺通过热解法合成精胺碳点、多巴胺碳点和精胺/多巴胺碳点（SPM–CDs、DA–CDs、SPM/DA–CDs），通过透射扫描电镜，X射线光电子能谱、红外光谱、Zeta电位、紫外光谱和荧光光谱对碳点进行表征，选取食源性致病菌金黄色葡萄球菌和大肠杆菌作为供试菌株，采用微量肉汤稀释法研究碳点及前体物的抗菌性能。结果 SPM–CDs、DA–CDs、SPM/DA–CDs的分散性好，平均粒径分别为（4.25±0.89）、（3.90±0.67）、（4.0±0.96）nm；在365 nm紫外灯照射下3种碳点均能发出荧光，表面都带有较高的正电荷并且含有C=C、C-O、O-H等化学键；抗菌实验表明，SPM/DA–CDs对金黄色葡萄球菌和大肠杆菌抑制效果显著，最小抑菌质量浓度分别为0.25 mg/mL和0.5 mg/mL，而SPM–CDs、DA–CDs和前体物对2种菌的抑制效果较差；SEM结果表明碳点能造成细菌表面凹陷、破裂，从而导致细菌死亡。结论 本研究合成的氨基功能化抗菌碳点具有优异...     

抗菌复合镀层的组成及性能研究

纳米TiO2已证明具有良好的抗菌性能,本研究采用化学复合镀的方法在钢铁基体上形成Ni-P-TiO2复合镀层,运用SEM、AES和XPS对镀层的表面形貌和组成进行了分析,并对其抗大肠杆菌和金黄色葡萄球菌的性能进行了定量测试.结果显示,Ni-P-TiO2镀层均匀、光亮;其相对原子百分数为74.51%Ni,13.37%P,3.02%Ti,6.81%O和1.38?,镀层对大肠杆菌的杀菌率为97.86%,对金黄色葡萄球菌的杀菌率为96.23%,显示出Ni-P-TiO2对上述两种细菌具有良好的抑制作用.     

Synthesis of Branched DNA Scaffolded Super‐Nanoclusters with Enhanced Antibacterial Performance

Metal nanoclusters (NCs) possess unique optical properties, and exhibit a wide variety of potential applications. DNA with robust molecular programmability is demonstrated as an ideal scaffold to regulate the formation of NCs, offering a rational approach to precisely tune the spatial structures of NCs. Herein, the first use of branched DNA as scaffold to regulate the formation of silver nanoclusters (super‐AgNC) is reported, in which the spatial structures are precisely designed and constructed. Super‐AgNC with tunable shapes and arm‐lengths including Y‐, X‐, and (Y–X)‐ shaped super‐AgNC is achieved. The molecular structures and optical properties of super‐AgNCs are systemically studied. As a proof of application, remarkably, super‐AgNCs exhibit superior antibacterial performance. In addition, super‐AgNCs show excellent biocompatibility with three types of tissue cells including 293T (human embryonic kidney cells), SMCs (vascular smooth muscle cells), and GLC‐82 (lung adenocarcinoma cells). These performances enable the super‐AgNCs adaptable in a variety of applications such as biosensing, bioimaging, and antibacterial agents.     

抗菌高分子材料研究进展及应对策略

日常生活中细菌感染极易引起人类的健康问题,因此开发更高效的抗菌材料以减小感染带来的风险,具有重要的科学意义和应用价值.其中,抗菌高分子材料由于具有良好的生物相容性、抗菌持久性、不易使细菌产生耐药性,同时其品种丰富、合成和改性相对简单,是当前抗菌材料研究的热点.根据抗菌高分子材料的最新发展趋势,文中着重介绍了阳离子抗菌材...     

锌铈共掺杂二氧化钛纳米材料制备与表征及其抗菌性能的研究

采用溶胶-凝胶法, 在不同的焙烧温度下合成锌/铈共掺杂二氧化钛纳米材料。用X射线衍射(XRD)、透射电子显微镜(TEM)、X射线光电子能谱(XPS)和紫外-可见漫反射光谱(DRS)对样品进行了表征。采用抑菌环法, 以大肠杆菌为实验菌种, 对Zn/Ce-TiO₂纳米材料抗菌性能进行检测。结果表明: 样品的结晶度和晶相完全取决于焙烧温度的高低; 部分锌进入二氧化钛晶格中, 其余掺杂离子以CeO₂和Zn₂Ti₃O₈形式存在; 与暗态下相比, 在可见光激发下, Zn/Ce-TiO₂纳米材料具有超强的抗菌性。对锌/铈共掺杂作用机制进行了深入探讨。     

The Effect of Interface Layer on the Binding Ability in PVD Surface Coating

The effect of the interface layer on binding ability PVD surface coating was researched . the experiment result showed that TiN was bonded to bulk material with the interface layer. The interface layer made the tow-phase region of α-Ti and TiN to chang to single-phase of TiN. the bonding strength of film and base interface was increased.     

不锈钢表面含银有机硅烷偶联剂抗菌耐蚀薄膜制备和性能

通过溶胶-凝胶方法在乙烯基三甲氧基硅烷偶联剂中加入银离子,得到含银有机硅烷水解溶液,在不锈钢表面制备了抗菌、耐蚀的不锈钢抗菌膜层,研究了银离子的掺入工艺以及薄膜的抗菌性能和耐蚀性能.抗菌性能研究结果表明:银离子含量增加到3%以上时,样品的抗菌性能均增加到99.9%以上.样品经过24h去离子水的浸泡后,所有样品的抗菌性能均有所降低;银离子含量越高的样品抗菌性能保持得越好,不锈钢表面经过预氧化处理的略优于表面未经预氧化处理的薄膜.10?Cl3溶液点蚀实验测试结果表明,样品的耐腐蚀性能有明显提高,点蚀率仅为相同条件下不锈钢的1/40.     

新型纳米无机抗菌剂的抗菌性能研究1.对金黄色葡萄球菌和白色念珠菌的抗菌作用

选择了金黄色葡萄球菌(staphylococcus aureus)和白色念珠菌(candida albicans)分别作为细菌和酵母菌的代表菌株,采用三角瓶振荡试验法,对纳米TiO2等4种新型纳米无机抗菌剂及一种微米抗菌剂的抗菌性能进行了系统的定性、定量研究,结果表明各种纳米抗菌剂的抗菌性能大大优于微米抗菌剂,并且价格较低的纳米TiO2及纳米ZnO对两种代表菌都表现出很强的抗菌能力,可用来代替价格昂贵的银离子化合物.此外,探讨了相关抗菌剂的抗菌机理.     

Bioactive Titanium Surfaces Enriched with Silver Nanoparticles Through an In Situ Reduction: Looking for a Balance Between Cytocompatibility and Antibacterial Activity

This research aims toward an antibacterial and osteoconductive Ti₆Al₄V surface by chemical etching–oxidation treatment and in situ reduction of silver nanoparticles. Starting from a previously developed process, already proved to enhance the osteoinductive ability of titanium, different parameters are changed to tailor the amount of silver and its distribution across the surface oxide layer thickness. The samples are characterized by scanning and transmission electron microscopy, energy-dispersive X-ray spectroscopy, release of silver, biofilm formation (Staphylococcus aureus), and cytocompatibility toward human osteoblasts progenitor cells. The total amount of silver in the surface oxide layer depends only on the concentration of the silver precursor. The time of the addition of the silver precursor, during the oxidation treatment, affects the oxide layer thickness, dimension, and distribution of the nanoparticles across the surface oxide: they are larger and accumulate on the outermost layer, if the addition occurs early. The maximum ion release occurs after 24 h and lasts up to 14 days; the later addition of silver precursors leads to sustaining the silver release for a longer time. The samples prepared with the higher concentration of the silver precursor are bactericide, but highly cytotoxic, whereas the other ones are bacteriostatic and moderately cytotoxic.     

银型抗菌活性碳纤维的结构及其抗菌性能的研究

利用活性碳纤维的高效吸附性能 ,通过浸渍法把银、银盐等金属或金属化合物吸附沉积在活性碳纤维上 ,并对其进行适当处理 ,制备出含细小银化合物或金属银颗粒的活性碳纤维。利用扫描电镜 ,X 射线衍射 ,ICP发射光谱等分析测定方法研究了银型抗菌活性碳纤维的结构。研究了这类银型抗菌活性碳纤维对大肠埃氏杆菌 (Escherichiacoli)和金黄色葡萄球菌 (Staphylococlusaureus)的杀灭效果。结果表明 ,这类银型抗菌活性碳纤维对大肠杆菌和金黄色葡萄球菌均有很强的杀灭能力 ,经其处理后 ,水中的大肠杆菌和金黄色葡萄菌被完全杀灭。对每次使用后被洗脱的银含量测定表明 ,水中所含银浓度低于饮水标准的要求