Enhancement in the limit of detection of lab-on-chip microfluidic devices using functional nanomaterials

Technological developments in recent years have witnessed a paradigm shift towards lab-on-chip devices for various diagnostic applications. Lab-on-chip technology integrates several functions typically performed in a large-scale analytical laboratory on a small-scale platform. These devices are more than the miniaturized versions of conventional analytical and diagnostic techniques. The advances in fabrication techniques, material sciences, surface modification strategies, and their integration with microfluidics and chemical and biological-based detection mechanisms have enormously enhanced the capabilities of these devices. The minuscule sample and reagent requirements, capillary-driven pump-free flows, faster transport phenomena, and ease of integration with various signal readout mechanisms make these platforms apt for use in resource-limited settings, especially in developing and underdeveloped parts of the world. The microfluidic lab-on-a-chip technology offers a promising approach to developing cost-effective and sustainable point-of-care testing applications. Numerous merits of this technology have attracted the attention of researchers to develop low-cost and rapid diagnostic platforms in human healthcare, veterinary medicine, food quality testing, and environmental monitoring. However, one of the major challenges associated with these devices is their limited sensitivity or the limit of detection. The use of functional nanomaterials in lab-on-chip microfluidic devices can improve the limit of detection by enhancing the signal-to-noise ratio, increasing the capture efficiency, and providing capabilities for devising novel detection schemes. This review presents an overview of state-of-the-art techniques for integrating functional nanomaterials with microfluidic devices and discusses the potential applications of these devices in various fields.     

Carrier-Free Enzyme Immobilizates for Flow Chemistry

For the development of efficient and green industrial processes, the combination of biocatalysis and flow chemistry holds great promises. Flow chemical utilization of biocatalysts, essentially made possible by the immobilization (or retention) of enzymes in flow reactors, has attracted increased academic attention during recent years. In the present review we present an overview of immobilization strategies suitable for flow chemistry, particularly focusing on recently developed carrier-free immobilization methods, highlighting advances in the field and presenting future trends.     

实现无机及分析化学实验绿色化的探索与实践

根据绿色化学使用化学药品的原则,就如何实现无机及分析化学实验的绿色化进行了初步的探索与实践。在无机及分析化学实验教学中,要让学生树立起绿色化学思想,加强和培养学生的绿色意识、环保意识。作者结合实际教学经验,指出改进实验方法,采用微型实验、小量-半微量实验,合理安排实验项目和次序,对实验产物进行回收利用是实现无机及分析化学实验绿色化的重要途径。     

Biomass-derived materials for electrochemical energy storages

During the past decade humans have witnessed dramatic expansion of fundamental research as well as the commercialization in the area of electrochemical energy storage, which is driven by the urgent demand by portable electronic devices, electric vehicles, transportation and storage of renewable energy for the power grid in the clean energy economy. Li-secondary batteries and electrochemical capacitors can efficiently convert stored chemical energy into electrical energy, and are currently the rapid-growing rechargeable devices. However, the characteristic (including energy density, cost, and safety issues, etc.) reported for these current rechargeable devices still cannot meet the requirements for electric vehicles and grid energy storage, which are mainly caused by the limited properties of the key materials (e.g. anode, cathode, electrolyte, separator, and binder) employed by these devices. Moreover, these key materials are normally far from renewable and sustainable. Therefore great challenges and opportunities remain to be realized are to search green and low-cost materials with high performances. A large number of the properties of biomass materials-such as renewable, low-cost, earth-abundant, specific structures, mechanical property and many others-are very attractive. These properties endow that biomass could replace some key materials in electrochemical energy storage systems. In this review, we focus on the fundamentals and applications of biomass-derived materials in electrochemical energy storage techniques. Specifically, we summarize the recent advances of the utilization of various biomasses as separators, binders and electrode materials. Finally, several perspectives related to the biomass-derived materials for electrochemical energy storages are proposed based on the reported progress and our own evaluation, aiming to provide some possible research directions in this field.     

Synthesis chemistry and application development of periodic mesoporous organosilicas

This paper provides a comprehensive and critical overview of recent advances in synthesis chemistry and application development of periodic mesoporous organosilicas (PMOs). A number of organic bridge-bonded functional and multifunctional PMOs with inorganic–organic hybridized framework have been synthesized from varieties of precursors. The syntheses of a series of PMOs have been accomplished typically by resorting to the co-condensation of the mixed precursors of tetraalkoxysilane and bridged organosiloxane, bridged organosiloxane with terminal organosiloxane, or the co-condensation of multiple bridged organosiloxane. The choice of precursors depends on the desired location of organic groups which can be either on the surface or within the pore wall in resulting PMOs. Besides precursors, synthesis conditions evidently play an important role in the formation, morphologies and pore structure of PMOs. Recent advances show that the morphologies and mesopores of PMOs can be adjusted by changing the synthetic parameters such as template, additives, pH value, and temperature. The PMOs with tunable composition, morphology and even-distributed hydrophobic organic groups in the framework endow such periodic mesoporous hybrids with great potentials in the fields of catalysis, environmental remediation, biology, pharmacy, analytical chemistry and microelectronics. The synthesis chemistry of PMOs and application development would particularly and continuously appeal to the researchers in chemistry and materials science in future.     

Functional micro/nanostructures: simple synthesis and application in sensors, fuel cells, and gene delivery

In order to develop new, high technology devices for a variety of applications, researchers would like to better control the structure and function of micro/nanomaterials through an understanding of the role of size, shape, architecture, composition, hybridization, molecular engineering, assembly, and microstructure. However, researchers continue to face great challenges in the construction of well-defined micro/nanomaterials with diverse morphologies. At the same time, the research interface where micro/nanomaterials meet electrochemistry, analytical chemistry, biomedicine, and other fields provides rich opportunities to reveal new chemical, physical, and biological properties of micro/nanomaterials and to uncover many new functions and applications of these materials. In this Account, we describe our recent progress in the construction of novel inorganic and polymer nanostructures formed through different simple strategies. Our synthetic strategies include wet-chemical and electrochemical methods for the controlled production of inorganic and polymer nanomaterials with well-defined morphologies. These methods are both facile and reliable, allowing us to produce high-quality micro/nanostructures, such as nanoplates, micro/nanoflowers, monodisperse micro/nanoparticles, nanowires, nanobelts, and polyhedron and even diverse hybrid structures. We implemented a series of approaches to address the challenges in the preparation of new functional micro/nanomaterials for a variety of important applications This Account also highlights new or enhanced applications of certain micro/nanomaterials in sensing applications. We singled out analytical techniques that take advantage of particular properties of micro/nanomaterials. Then by rationally tailoring experimental parameters, we readily and selectively obtained different types of micro/nanomaterials with novel morphologies with high performance in applications such as electrochemical sensors, electrochemiluminescent sensors, gene delivery agents, and fuel cell catalysts. We expect that micro/nanomaterials with unique structural characteristics, properties, and functions will attract increasing research interest and will lead to new opportunities in various fields of research.     

化学实验教学中学生环保意识的培养

近年来,中国中学推行新教材,颁发了新课程标准,实行教育改革。新教材新课程,中学教学的开展遇到了前所未有的机遇和挑战。文章以新课标化学为前提,在高中化学实验教学中通过规范学生实验操作、推广微型化学实验、加强药物回收处理并进行药物重复利用,以及化学实验的绿色化改进与设计等方面进行培养学生的环保意识的教学实践,从而提高了学生的环保意识并树立正确的科学发展观。     

绿色化学技术在环境污染治理中的应用

论述了绿色化学的原理、研究现状,总结了绿色化学技术的应用进展。从大气污染、水污染和固体废物三方面论述了绿色化学技术在环境污染治理中的应用情况,并提出应用绿色化学技术来解决环境污染问题是环境保护的发展方向。工业、农业、日常生活等采用无毒、无害并可循环使用的物料,化学反应的绿色化,是从“本”治理环境污染的重要途径。     

Challenges for the Development of New Non-Toxic Antifouling Solutions

Marine biofouling is of major economic concern to all marine industries. The shipping trade is particularly alert to the development of new antifouling (AF) strategies, especially green AF paint as international regulations regarding the environmental impact of the compounds actually incorporated into the formulations are becoming more and more strict. It is also recognised that vessels play an extensive role in invasive species propagation as ballast waters transport potentially threatening larvae. It is then crucial to develop new AF solutions combining advances in marine chemistry and topography, in addition to a knowledge of marine biofoulers, with respect to the marine environment. This review presents the recent research progress made in the field of new non-toxic AF solutions (new microtexturing of surfaces, foul-release coatings, and with a special emphasis on marine natural antifoulants) as well as the perspectives for future research directions.     

Origins,current status,and future challenges of green chemistry

Over the course of the past decade, green chemistry has demonstrated how fundamental scientific methodologies can protect human health and the environment in an economically beneficial manner. Significant progress is being made in several key research areas, such as catalysis, the design of safer chemicals and environmentally benign solvents, and the development of renewable feedstocks. Current and future chemists are being trained to design products and processes with an increased awareness for environmental impact. Outreach activities within the green chemistry community highlight the potential for chemistry to solve many of the global environmental challenges we now face. The origins and basis of green chemistry chart a course for achieving environmental and economic prosperity inherent in a sustainable world.     

The transaldolase family: new synthetic opportunities from an ancient enzyme scaffold

Aldol reactions constitute a powerful methodology for carbon-carbon bond formation in synthetic organic chemistry. Biocatalytic carboligation by aldolases offers a green, uniquely regio- and stereoselective tool with which to perform these transformations. Recent advances in the field, fueled by both discovery and protein engineering, have greatly improved the synthetic opportunities for the atom-economic asymmetric synthesis of chiral molecules with potential pharmaceutical relevance. New aldolases derived from the transaldolase scaffold (based on transaldolase B and fructose-6-phosphate aldolase from Escherichia coli) have been shown to be unusually flexible in their substrate scope; this makes them particularly valuable for addressing an expanded molecular range of complex polyfunctional targets. Extensive knowledge arising from structural and molecular biochemical studies makes it possible to address the remaining limitations of the methodology by engineering tailored biocatalysts.     

Polymer electrolytes integrated with ionic liquids for future electrochemical devices

The global energy crisis and an increase in environmental pollution in the recent years have drawn the attention of the scientific community towards the development of efficient electrochemical devices. Polymers containing charged species have the potential to serve as electrolytes in next‐generation devices and achieving high ion transport properties in these electrolytes is the key to improving their efficiency. In this article, we explore ways to improve the ion transport properties of solid polymer electrolytes by focusing on the use of ionic liquids (ILs). The application of IL‐incorporated polymer electrolytes in lithium batteries, high temperature fuel cells, and electro‐active actuators is summarized. For each system, the current level of understanding of the diverse factors affecting the transport properties of polymer electrolytes integrated with ILs is presented, in addition to the challenges encountered and strategies toward obtaining significantly improved device performances. The creation of self‐assembled morphologies in IL‐containing polymer electrolytes by the use of block copolymers is particularly highlighted as a novel prospective technique geared towards obtaining next‐generation electrochemical devices with enhanced performances. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

中学化学实验教学绿色化探讨

中学化学实验教学中树立绿色化学实验理念,是贯彻科学发展观,保护学生身体健康,保护环境,节约化学实验资源,提高办学效益,培养学生环境保护观念的重要举措。化学实验教学中可以通过化学实验微型化;化学实验废气、废液、废渣"零排放";以及用多媒体教学演示或仿真化学实验来实现绿色化学实验教学,树立绿色化学实验理念。     

近十年来离子液体在萃取金属方面的研究进展

离子液体具有不挥发、稳定性好、结构可调、无毒、对环境友好等特点,被认为是一种可替代传统溶剂的新型绿色溶剂,在电化学、分析化学、有机合成及催化反应等领域都有广泛的应用.主要根据离子液体在萃取分离中的应用研究,将近十年来离子液体对于如重金属、碱金属和碱土金属、稀土金属、稀有金属及放射性金属等各种金属离子的萃取效果进行了综述.     

Radiation-grafted materials for energy conversion and energy storage applications

Polymer electrolyte membranes are key components in electrochemical power sources that are receiving ever-growing demand for the development of more efficient, reliable and environmentally friendly energy systems. Ongoing research is focusing on materials with high ionic conductivity and stability, at low cost. Among different methods, radiation-induced grafting is a universal attractive method for preparation of polymer electrolyte materials with tunable properties for various energy conversion and energy storage applications. This review addresses recent advances in the application of radiation-induced grafting techniques for the preparation of polymer electrolyte membranes/separators for emerging electrochemical devices such as fuel cells, batteries and supercapacitors. The challenges associated with the current state-of-the-art materials are highlighted, together with new directions that should be considered for future research.     

Bioelectrochemical interface engineering: toward the fabrication of electrochemical biosensors, biofuel cells, and self-powered logic biosensors

Over the past decade, researchers have devoted considerable attention to the integration of living organisms with electronic elements to yield bioelectronic devices. Not only is the integration of DNA, enzymes, or whole cells with electronics of scientific interest, but it has many versatile potential applications. Researchers are using these ideas to fabricate biosensors for analytical applications and to assemble biofuel cells (BFCs) and biomolecule-based devices. Other research efforts include the development of biocomputing systems for information processing. In this Account, we focus on our recent progress in engineering at the bioelectrochemical interface (BECI) for the rational design and construction of important bioelectronic devices, ranging from electrochemical (EC-) biosensors to BFCs, and self-powered logic biosensors. Hydrogels and sol-gels provide attractive materials for the immobilization of enzymes because they make EC-enzyme biosensors stable and even functional in extreme environments. We use a layer-by-layer (LBL) self-assembly technique to fabricate multicomponent thin films on the BECI at the nanometer scale. Additionally, we demonstrate how carbon nanomaterials have paved the way for new and improved EC-enzyme biosensors. In addition to the widely reported BECI-based electrochemical impedance spectroscopy (EIS)-type aptasensors, we integrate the LBL technique with our previously developed "solid-state probe" technique for redox probes immobilization on electrode surfaces to design and fabricate BECI-based differential pulse voltammetry (DPV)-type aptasensors. BFCs can directly harvest energy from ambient biofuels as green energy sources, which could lead to their application as simple, flexible, and portable power sources. Porous materials provide favorable microenvironments for enzyme immobilization, which can enhance BFC power output. Furthermore, by introducing aptamer-based logic systems to BFCs, such systems could be applied as self-powered and intelligent aptasensors for the logic detection. We have developed biocomputing keypad lock security systems which can be also used for intelligent medical diagnostics. BECI engineering provides a simple but effective approach toward the design and fabrication of EC-biosensors, BFCs, and self-powered logic biosensors, which will make essential contributions in the development of creative and practical bioelectronic devices. The exploration of novel interface engineering applications and the creation of new fabrication concepts or methods merit further attention.     

绿色化学及其技术在水处理的应用

近年来绿色化学及其技术的应用已经成为环境保护和防止污染的重要方面。绿色化学可将污染控制在一定水平 ,即在化学品的制造和应用中降低或消除有毒有害物质。水处理缓蚀剂和阻垢剂作为一类化学品 ,如果在这些领域应用绿色化学技术 ,可以减少或消除许多有毒有害的化学品 ,并在此基础上开发新型的环境友好型的水处理药剂。     

绿色过程系统合成与设计的研究与展望

过程工业的高速发展导致环境污染不断加剧，对传统工业的改造和实现清洁生产离不开绿色过程系统合成的理论和方法. 本工作对绿色过程合成的相关研究进展进行了综述. 首先对现有的环境影响评价体系进行了分类、归纳和总结，评述了其各自的特点和作用，以及具体应用；其次对绿色过程合成的模型化和算法的研究进展进行了详细论述，介绍了其在废物(水)最小化、分离系统集成等方面的应用；论述了绿色过程合成在化工过程绿色设计中的应用和发展趋势. 将绿色化学原理和系统集成的普适性理论相结合，提出了绿色度的理论和方法，阐明了其研究内容和拟解决的关键科学问题，提出量化物质、能量、过程和系统的绿色度的原则方法，通过多目标优化实现不同层次系统的生态、经济和社会效益的全局最优.     

Gold nanoparticle-based electrochemical biosensors

The unique properties of gold nanoparticles to provide a suitable microenvironment for biomolecules immobilization retaining their biological activity, and to facilitate electron transfer between the immobilized proteins and electrode surfaces, have led to an intensive use of this nanomaterial for the construction of electrochemical biosensors with enhanced analytical performance with respect to other biosensor designs. Recent advances in this field are reviewed in this article. The advantageous operational characteristics of the biosensing devices designed making use of gold nanoparticles are highlighted with respect to non-nanostructured biosensors and some illustrative examples are commented. Electrochemical enzyme biosensors including those using hybrid materials with carbon nanotubes and polymers, sol-gel matrices, and layer-by-layer architectures are considered. Moreover, electrochemical immunosensors in which gold nanoparticles play a crucial role in the electrode transduction enhancement of the affinity reaction as well as in the efficiency of immunoreagents immobilization in a stable mode are reviewed. Similarly, recent advances in the development of DNA biosensors using gold nanoparticles to improve DNA immobilization on electrode surfaces and as suitable labels to improve detection of hybridization events are considered. Finally, other biosensors designed with gold nanoparticles oriented to electrically contact redox enzymes to electrodes by a reconstitution process and to the study of direct electron transfer between redox proteins and electrode surfaces have also been treated.     

Advancing glasses through fundamental research

Fundamental research is critical for enabling future breakthroughs in glass science and technology. This is especially true as we approach a new decade of glass research, when addressing technological challenges will require an unprecedented knowledge of structure–property relationships and of the thermodynamics and kinetics of the glassy state. Proper understanding of these issues can be gained only through advances in our knowledge of the physics and chemistry of the glassy state.Recent advances in modeling and simulation have enabled researchers to study glass physics and chemistry at the atomic level. Molecular dynamics and Monte Carlo simulations have proved invaluable for understanding the relationships between glass structure and properties. More recently, a master equation approach has been applied in the energy landscape framework to allow for direct simulation of glass transition range behavior on a laboratory time scale.Furthermore, recent experimental studies have led to a great growth in our understanding of pressure effects in glass. In particular, distinct types of glassy phases can be produced using the same composition but different pressure conditions. This effect, dubbed “polyamorphism,” has provided a new depth to our understanding of the thermodynamics and statistical mechanics of glass.