纳米生物技术在医学中的应用

近年来纳米材料和纳米生物技术在临床治疗及临床诊断方面的应用越来越广泛,纳米药物、纳米医用材料、纳米芯片技术、体外诊断试剂逐渐开发并取得了重要进展。主要从纳米医疗和纳米诊断这两方面对纳米材料和纳米生物技术的现状及其发展前景进行了阐述。

海藻酸-磷脂微囊复合水凝胶的制备、表征及毒理学分析

采用薄膜分散法合成磷脂微囊,根据胶粒的双电层理论,通过在微囊中加入氯化锰、氯化钙和氯化镁电解质溶液,使微囊处于相对稳定的状态.研究发现加入氯化锰和氯化钙溶液,微囊胶体的粒径没有明显的变化,但加入一定浓度氯化镁溶液,其粒径明显变大.为了进一步增加磷脂微囊稳定性,将氯化锰、氯化钙、氯化镁磷脂微囊胶体分别与海藻酸钠(SA)溶液混合.结果表明,氯化镁与SA几乎不能形成水凝胶,氯化钙与SA形成水凝胶能力强于氯化锰.微囊胶体溶液中的磷脂酰丝氨酸(PS)可以与Ca^(2+)和Mg^(2+)键合形成PS-Ca^(2+)和PS-Mg^(2+),但不能与Mn^(2+)键合形成PS-Mn^(2+).对氯化钙磷脂微囊与海藻酸钠合成的复合水凝胶的形貌、溶胀率及细胞毒性进行了表征,结果表明,氯化钙与SA形成的水凝胶可以捕获胶体中磷脂微囊,且形貌规整,结构稳定,无细胞毒性.

Porous bowl-shaped VS2 nanosheets/graphene composite for high-rate lithium-ion storage

Two-dimensional (2D) layered vanadium disulfide (VS2) is a promising anode material for lithium ion batteries (LIBs) due to the high theoretical capacity.However,it remains a challenge to synthesize monodispersed ultrathin VS2 nanosheets to realize the full potential.Herein,a novel solvothermal method has been developed to prepare the monodispersed bowl-shaped NH3-inserted VS2 nanosheets (VS2).The formation of such a unique structure is caused by the blocked growth of (001) or (002) crystal planes in combination with a ripening process driven by the thermodynamics.The annealing treatment in Ar/H2creates porous monodispersed VS2(H-VS2),which is subsequently integrated with graphene oxide to form porous monodispersed H-VS2/rGO composite coupled with a reduction process.As an anode material for LIBs,H-VS2/rGO delivers superior rate performance and longer cycle stability:a high average capacity of 868/525 mAh g^-1 at a current density of 1/10 A g^-1;a reversible capacity of 1177/889 mAh g^-1 after 150/500 cycles at 0.2/1 A g^-1.Such excellent electrochemical performance may be attributed to the increased active sites available for lithium storage,the alleviated volume variations and the shortened Li-ion diffusion induced from the porous structure with large specific surface area,as well as the protective effect from graphene nanosheets.

Molybdenum and tungsten chalcogenides for lithium/sodium-ion batteries: Beyond MoS2

Molybdenum and tungsten chalcogenides have attracted tremendous attention in energy storage and conversion due to their outstanding physicochemical and electrochemical properties.There are intensive studies on molybdenum and tungsten chalcogenides for energy storage and conversion,however,there is no systematic review on the applications of WS2,Mo Se2and WSe2as anode materials for lithium-ion batteries(LIBs)and sodium-ion batteries(SIBs),except Mo S2.Considering the importance of these contents,it is extremely necessary to overview the recent development of novel layered WS2,Mo Se2and WSe2beyond Mo S2in energy storage.Here,we will systematically overview the recent progress of WS2,Mo Se2and WSe2as anode materials in LIBs and SIBs.This review will also discuss the opportunities,and perspectives of these materials in the energy storage fields.

Electrospun CoSe@N-doped carbon nanofibers with highly capacitive Li storage

One-dimensional nano-structured materials have attracted attention due to its unique properties afforded such as the across-linked structures and large aspect ratios.In this work,one-dimensional CoSe@N-doped carbon nanofibers(CoSe@NCNFs)are successfully by combining the techniques of electrospinning and annealing.Selenium powder are directly dispersed in the polyacrylonitrile/N,N-Dimethylformamide(DMF)solution containing cobalt salt to form the product.The performance of these materials was investigated in Li-ion batteries after the annealing at different temperatures.The Co Se@NC nanofibers annealed at 550℃(CoSe@NC-550)and displayed excellent storage properties,affording a high capacity of 796 m Ah·g-1at a current density of 1 A·g^-1 for 100 cycles.Moreover,it is confirmed that the pseudocapacitive contribution of CoSe@NC-550 is up to 72.8%at the scan rate of 1 mV/s through the cyclic voltammetry analysis.

Electrochemical CO2 reduction over nitrogen-doped SnO2 crystal surfaces

Crystal planes of a catalyst play crucial role in determining the electrocatalytic performance for CO2 reduction.The catalyst SnO2 can convert CO2 molecules into valuable formic acid(HCOOH).Incorporating heteroatom N into SnO2 further improves its catalytic activity.To understand the mechanism and realize a highly efficient CO2-to-HCOOH conversion,we used density functional theory(DFT)to calculate the free energy of CO2 reduction reactions(CO2RR)on different crystal planes of N-doped SnO2(N-SnO2).The results indicate that N-SnO2 lowered the activation energy of intermediates leading to a better catalytic performance than pure SnO2.We also discovered that the N-Sn O2 (211)plane possesses the most suitable free energy during the reduction process,exhibiting the best catalytic ability for the CO2-to-HCOOH conversion.The intermediate of CO2RR on N-SnO2 is HCOO*or COOH* instead of OCHO*.These results may provide useful insights into the mechanism of CO2RR,and promote the development of heteroatomdoped catalyst for efficient CO2RR.

Metal porphyrin intercalated reduced graphene oxide nanocomposite utilized for electrocatalytic oxygen reduction

In this paper, we report a simple and facile self-assembly method to successfully fabricate cationic metal porphyrin-MtTMPyP(Mt= Cobalt(Ⅱ), Manganese(Ⅲ), or Iron(Ⅲ); TMPyP = 5, 10, 15, 20-tetrakis(N-methylpyridinium-4-yl) porphyrin) intercalated into the layer of graphene oxide(GO) by the cooperative effects of electrostatic and π-π stacking interaction between positively charged metal porphyrin and negatively charged GO sheets. Followed by reduction with hydrazine vapor, a series of novel 2 D MtTMPyP/rGO_n were fabricated. The as-prepared 2 D hybrids were fully characterized and tested as non-noble metal catalysts for oxygen reduction reaction(ORR) in an alkaline medium. The MtTMPyP/rGO_n hybrids, especially CoTMPyP/rGO_5, demonstrated an improved electrocatalytic activity for ORR and a number of exchanged electrons close to 4-electron reaction, increased stability and excellent tolerance to methanol, showing a potential alternative catalyst for ORR in fuel cells and air batteries.

Recent progress in 2D materials for flexible supercapacitors

High performance supercapacitors coupled with mechanical flexibility are needed to drive flexible and wearable electronics that have anesthetic appeal and multi-functionality. Two dimensional（2D） materials have attracted attention owing to their unique physicochemical and electrochemical properties, in addition to their ability to form hetero-structures with other nanomaterials further improving mechanical and electrochemical properties. After a brief introduction of supercapacitors and 2D materials, recent progress on flexible supercapacitors using 2D materials is reviewed. Here we provide insights into the structure–property relationships of flexible electrodes, in particular free-standing films. We also present our perspectives on the development of flexible supercapacitors.

Controllable synthesis of Fe–N4 species for acidic oxygen reduction

Controllable design and synthesis of catalysts with the target active sites are extremely important for their applications such as for the oxygen reduction reaction(ORR)in fuel cells.However,the controllably synthesizing electrocatalysts with a single type of active site still remains a grand challenge.In this study,we developed a facile and scalable method for fabricating highly efficient ORR electrocatalysts with sole atomic Fe-N4 species as the active site.Herein,the use of cost-effective highly porous carbon as the support not only could avoid the aggregation of the atomic Fe species but also a feasible approach to reduce the catalyst cost.The obtained atomic Fe-N4 in activated carbon(aFe@AC)shows excellent ORR activity.Its half-wave potential is 59 mV more negative but 47 mV more positive than that of the commercial Pt/C in acidic and alkaline electrolytes,respectively.The full cell performance test results show that the aFe@AC sample is a promising candidate for direct methanol fuel cells.This study provides a general method to prepare catalysts with a certain type of active site and definite numbers.

Flexible quasi-solid-state dual-ion asymmetric supercapacitor based on Ni（OH）2 and Nb2O5 nanosheet arrays

Increasing the energy density, power density as well as widening the operation voltage are essential to electrochemical capacitors to meet the practical energy demands. Herein, a novel flexible quasi-solid-state dual-ion asymmetric supercapacitor(ASC) with Ni(OH)2 and Nb2O5 nanosheets directly grown on stainless steel mesh is developed. In the dual-ion ASC, Nb2O5 negative and Ni(OH)2 positive electrodes react with Li+ and OH- respectively in alkaline gel electrolyte to store energy, which is quite different from conventional alkali metal ion SCs and alkaline SCs. The as-assembled flexible device has an extended working voltage of 1.7 V and delivers a capacity of 5.37 mAh cm-2, a maximum energy density and power density of 0.52 mWh cm-3 and 170 mW cm-3 , respectively. The device maintains around 60% capacity retention after long cycling up to 1000 cycles. Moreover, our device can light up a LED light efficiently upon fast charging. The proposed quasi-solid-state dual-ion ASC has potential applications in future portable electronics and flexible energy storage devices.

Activation of urchin-like Ni-doped W_(18)O_(49)/NF by electrochemical tuning for efficient water splitting

The electrochemical conversion is closely correlated with the electrocatalytic activities of the electrocatalyst.Herein,the urchin-like Ni-doped W_(18)O_(49)/NF with enriched active sites was prepared by solvothermal method followed by a low-temperature pyrolysis treatment was reported.Results demonstrate that the incorporation of Ni-doping triggers the lattice distortion of W_(18)O_(49) for the increasement of oxygen defects.Further,high-valent W^(6+)are partially reduced to low-valent W^(4+),wherein the electrons originate from the oxidation process of Ni^(2+)to Ni^(3+).The Ni^(3+)ions show an enhanced orbital overlap with the OER reaction intermediates.The generated W^(4+)ions contribute to release oxygen vacancies,eventually reorganizing Ni-doped W_(18)O_(49)/NF to unique electrochemical active species with a special amorphous-crystalline interface(AM/NiWO_x/NiOOH/NF).Simultaneously,the reconstruction results in an optimized valence band and conduction band.Eventually,the resultant AM/NiWO_x/NiOOH/NF with abundant active sites and improved oxidation/reduction capability exhibits more superior catalytic performance compared with the Ni-doped W_(18)O_(49)/NF counterpart.This study gives more insights in the electrochemical evolution of the tungsten-based oxide and provides effective strategies for optimizing the catalytic activity of materials with inherent hydrogen evolution reaction limitations.

Measuring Electrospun Nanofibre Diameter： a Novel Approach

基于为电镀物品的图象分析，旋转 nano 纤维直径测量被介绍的一个新方法。首先，卡住进程的电镀物品获得的 nano 纤维网的 SEM 显微图用本地 thresholding 方法被变换成二进制图象。在下一步，骨骼和距离，转变图象被产生。然后，引起不真实的大小的交叉点被识别并且从骨骼搬迁了。最后，产生骨骼和距离转变了图象被用来决定纤维直径。方法被一幅模仿的图象评估，已知的特征产生了由 ?- 随意过程。结果显示这条途径在快做是成功的，电镀物品的精确自动化大小旋转了纤维直径。

Facile Fabrication of Ag Nanocrystals Encapsulated in Nitrogen-doped Fibrous Carbon as an Efficient Catalyst for Lithium Oxygen Batteries

A facile synthesis of Ag nanocrystals encapsulated in nitrogen-doped carbon fiber(NCF)is proposed,based on the simultaneous reaction between pyrrole and Ag^(+)ions in an aqueous solvent followed by a heat treatment.The as-prepared Ag/NCF demonstrated superior catalytic behavior toward ORR and OER.Besides improved cycling stability,a much lower discharge/charge gap of 0.89 V(vs Li/Li^(+))compared with 1.38 V for NCF cathode with a fixed capacity of 500 m Ah g^(-1)was obtained in lithium oxygen batteries.The introduction of Ag crystals into NCF facilitates the oxygen reduction reaction/oxygen evolution reaction kinetics.X-ray diffraction analysis coupled with Raman spectroscopy confirmed that Ag/NCF cathode could reversibly catalyze Li_(2)O_(2)formation and decomposition.The NCF matrix offers a conductive network to realize rapid mass transfer and the encapsulated Ag nanocrystals supplied effective catalytic active sites.The combined action between both contributes to the superior electrocatalytic performance.

Novel water-based nanolubricant with superior tribological performance in hot steel rolling

Novel water-based nanolubricants using TiO2 nanoparticles(NPs)were synthesised by adding sodium dodecyl benzene sulfonate(SDBS)and glycerol,which exhibited excellent dispersion stability and wettability.The tribological performance of the synthesised nanolubricants was investigated using an Rtec ball-on-disk tribometer,and their application in hot steel rolling was evaluated on a 2-high Hille 100 experimental rolling mill,in comparison to those without SDBS.The water-based nanolubricant containing 4 wt%TiO2 and 0.4 wt%SDBS demonstrated superior tribological performance by decreasing coefficient of friction and ball wear up to 70.5%and 84.3%,respectively,compared to those of pure water.In addition to the lubrication effect,the suspensions also had significant effect on polishing of the work roll surface.The resultant surface improvement thus enabled the decrease in rolling force up to 8.3%under a workpiece reduction of 30%at a rolling temperature of 850◦C.The lubrication mechanisms were primarily ascribed to the formation of lubricating film and ball-bearing effect of the TiO2 NPs.

Structurally ordered high-entropy intermetallic nanoparticles with enhanced C–C bond cleavage for ethanol oxidation

Efficient ethanol oxidation reaction(EOR)is challenging due to the multiple reaction steps required to accomplish full oxidation to CO_(2) in fuel cells.Highentropy materials with the adjustable composition and unique chemical structure provide a large configurational space for designing high-performance electrocatalysts.Herein,a new class of structurally ordered PtRhFeNiCu high-entropy intermetallics(HEIs)is developed as electrocatalyst,which exhibits excellent electrocatalytic activity and CO tolerance for EOR compared to high-entropy alloys(HEAs)comprising of same elements.When the HEIs are used as anode catalysts to be assembled into a high-temperature polybenzimidazole-based direct ethanol fuel cell,the HEIs achieve a high power density of 47.50 mW/cm^(2),which is 2.97 times of Pt/C(16.0mW/cm^(2)).Online gas chromatography measurements show that the developed HEIs have a stronger C–C bond-breaking ability than corresponding HEAs and Pt/C catalysts,which is further verified by density functional theory(DFT)calculations.Moreover,DFT results indicate that HEIs possess higher stability and electrochemical activity for EOR than HEAs.These results demonstrate that the HEIs could provide a new platform to develop highperformance electrocatalysts for broader applications.

Perspective on cycling stability of lithium-iron manganese phosphate for lithium-ion batteries

Lithium-iron manganese phosphates(LiFex Mn_(1-x)PO_(4),0.1<x<0.9)have the merits of high safety and high working voltage.However,they also face the challenges of insufficient conductivity and poor cycling stability.Some progress has been achieved to solve these problems.Herein,we firstly summarized the influence of different electrolyte systems on the electrochemical performance of LiFexMn_(1-x)PO_(4),and then discussed the effect of element doping,lastly studied the influences of conductive layer coating and morphology control on the cycling stability.Finally,the prospects and challenges of developing high-cycling LiFexMn_(1-x)PO_(4) were proposed.

Scale up of reactors for carbon dioxide reduction

In recent times there has been a great deal of interest in the conversion of carbon dioxide into more useful chemical compounds.On the other hand,the translation of these developments in electrochemical reduction of carbon dioxide from the laboratory bench to practical scale remains an underexplored topic.Here we examine some of the major challenges,demonstrating some promising strategies towards such scale-up,including increased electrode area and stacking of electrode pairs in different configurations.We observed that increasing the electrode area from 1 to 10 cm^(2) led to only a 4%drop in current density,with similarly small penalties realised when stacking sub-cells together.

Dynamic investigation of oxygen defects on transition metal-based electrocatalysts:formation,characterization,and mechanism during alkaline oxygen evolution reaction

Oxygen defects play a critical role in the electrocatalytic oxygen evolution reaction(OER).Therefore,in-depth understanding the structure-activity-mechanism relationship of these defects is the key to design efficient OER electrocatalysts.This relationship needs to be understood dynamically due to the potential for irreversible phase transitions during OER.Consequently,significant efforts have been devoted to study the dynamic evolution of oxygen defects to shed light on the OER mechanism.This review critically examines and analyzes the dynamic processes occurring at oxygen defect sites during OER,including defect formation and defect evolution mechanisms,along with the advanced characterization techniques needed to understand these processes.This review aims to provide a comprehensive understanding of high-efficiency electrocatalysts,with a particular emphasis on the importance of in situ monitoring the dynamic evolution of oxygen defects,providing a new perspective towards efficient OER electrocatalyst design.

Perspective of nitrate reduction and nitrogen neutral cycle

Nitrogen is one of the most abundant elements on earth and plays an indispensable role in living organisms and industrial processes[1].The natural nitrogen cycle is a basic element cycle in the global biogeo-chemical processes,permitting harmless dinitrogen in the atmosphere to be used in the biological nitrogen fixation.

生物三维打印的研究进展

三维(3D)打印具有灵活性和精密性的特点,已在军工、航天等制造行业中发挥重要作用.随之兴起的生物3D打印在再生医学领域同样具有广泛的应用前景.生物3D打印是将打印的墨水改成含有活细胞的混合物,从而构建活体组织器官.目前生物3D打印更多的是应用于硬组织的仿生重建和新型给药装置的制备,但具有生物活性、更复杂的组织器官的重建还处于探索阶段.本文主要对3D打印在生物医学上的应用进行综述,讨论生物3D打印目前面临的问题,并探讨生物3D打印的未来发展方向.