Microfluidics for selective concentration of nanofluid streams containing magnetic nanoparticles

Microfluidics is well-known for many Lab-on-a-Chip applications including sensing, cell sorting, separation, chemical reaction, emulsification, de-emulsification, droplet generation, energy generation and similar applications. The current research scenario in the field of interfacial science and colloidal technology has facilitated the advancement of microfluidics as a miniaturized option for many targeted tasks. Here we show how the microfluidics offers a low-cost solution for concentrating the dispersion of magnetic nanoparticles. The synthesized nanofluids were fed to the microchannels subjected to magnetic field. It has been found that the feed flow rate is one of the very crucial factors which affect the control of concentration of the nanofluids.     

Review of membranes in microfluidics

This review reports the progress on the recent development of membranes in microfluidics. First of all, the definition and basic concepts of membranes are given. Second, the manufacturing methods of membranes in microfluidics are illustrated and discussed. And lastly, the applications of membranes in microfluidics that are the focus of this work are discussed including cells, proteins, microreactors, gas detection, drug screening, electrokinetical fluids, pump and valve and fluid transport control, chemical reagents detection and so on. A variety of microfluidic devices designed containing membranes are expounded and analyzed. This paper will provide a valuable reference to designers who research membranes and microfluidics for various applications. © 2016 Society of Chemical Industry     

3D Printed Tooling for Injection Molded Microfluidics

Microfluidics have been used for several decades to conduct a wide range of research in chemistry and the life sciences. The reduced dimensions of these devices give them advantages over classical analysis techniques such as increased sensitivity, shorter analysis times, and lower reagent consumption. However, current manufacturing processes for microfluidic chips either limit them to materials with unwanted properties, or are not cost-effective for rapid-prototyping approaches. Here the authors show that inlays for injection moulding can be 3D printed, thus reducing the skills, cost, and time required for tool fabrication. They demonstrate the importance of orientation of the part during 3D printing so that features as small as 100 × 200 µm can be printed. They also demonstrate that the 3D printed inlay is durable enough to fabricate at least 500 parts. Furthermore, devices can be designed, manufactured, and tested within one working day. Finally, as demonstrators they design and mould a microfluidic chip to house a plasmonic biosensor as well as a device to house liver organoids showing how such chips can be used in organ-on-a-chip applications. This new fabrication technique bridges the gap between small production and industrial scale manufacturing, while making microfluidics cheaper, and more widely accessible.     

Recent developments in scale-up of microfluidic emulsion generation via parallelization

Microfluidics affords precise control over the flow of multiphasic fluids in micron-scale channels. By manipulating the viscous and surface tension forces present in multiphasic flows in microfluidic channels, it is possible to produce highly uniform emulsion droplets one at a time. Monodisperse droplets generated based on microfluidics are useful templates for producing uniform microcapsules and microparticles for encapsulation and delivery of active ingredients as well as living cells. Also, droplet microfluidics have been extensively exploited as a means to enable highthroughput biological screening and assays. Despite the promise droplet-based microfluidics hold for a wide range of applications, low production rate (<<10mL/hour) of emulsion droplets has been a major hindrance to widespread utilization at the industrial and commercial scale. Several reports have recently shown that one way to overcome this challenge and enable mass production of microfluidic droplets is to parallelize droplet generation, by incorporating a large number of droplet generation units (N>>100) and networks of fluid channels that distribute fluid to each of these generators onto a single chip. To parallelize droplet generation and, at the same time, maintain high uniformity of emulsion droplets, several considerations have to be made including the design of channel geometries to ensure even distribution of fluids to each droplet generator, methods for large-scale and uniform fabrication of microchannels, device materials for mechanically robust operation to withstand high-pressure injection, and development of commercially feasible fabrication techniques for three-dimensional microfluidic devices. We highlight some of the recent advances in the mass production of highly uniform microfluidics droplets via parallelization and discuss outstanding issues.     

Exploitation of Feedback in Enzyme-catalysed Reactions

Some cellular systems, such as yeast, bacteria and slime mould, display dynamic behavior including switches and rhythms driven by feedback in enzyme-catalysed reactions. The mechanisms of these processes have been well investigated and recent attention has turned to generating similar responses in synthetic biocatalytic systems, with a view to creating bioinspired analogues for applications. Here we discuss how feedback arises in the reaction mechanisms of some enzyme-catalyzed reactions in vitro, the behaviour obtained and the emerging applications. These autocatalytic reactions may provide insights into behaviour in cellular systems as well as new methods for drug delivery, sensing and repair that can be exploited in living systems.     

液滴流微反应器的基础研究及其应用

综述了近些年来快速发展的液滴微流控技术, 回顾了微流控系统中液滴的基本行为, 如液滴的生成、运动、聚并和分裂等研究进展, 重点探讨微液滴作为反应器其内部的流动、传质和反应过程, 以及液滴流微反应器已有的和潜在的重要应用价值。通过精确调控液滴在微尺度上的行为(产生、聚并与分裂、内部的混合与反应等), 使单个液滴成为新型受限空间内的微型间歇反应器, 而微通道内的液滴流进而形成了若干间歇反应器构成的连续流反应器新型式。除了微流控技术普遍具有的微小尺寸效应带来传质传热强化、易于放大等优势外, 液滴流微反应器还具有诸如避免试剂交叉污染、液滴内部可控混合、易于独立调控、便于高通量筛选或者制备等独特特点, 使得其在功能材料制备、化学合成以及生物化工方面有着广泛的应用。     

Engineering molecularly imprinted polymer (MIP) materials: Developments and challenges for sensing and separation technologies

Molecular imprinting, artificial receptors, plastic antibodies are terms associated with synthetic materials capable of chemical and biological sensing. Through the years, these sensors have advanced greatly not only in analytical chemistry; they have high utility for environmental, health, security, military, etc. monitoring and separations applications. New transduction methods and miniaturization have enabled in-situ and real-time sensing capabilities. On the other hand, they have high utility as matrices for chemical and biological separations. The challenge of employing molecularly imprinted polymers or MIPs as receptors lie in demonstrating high selectivity and sensitivity. Robustness and cost are also important considerations. Traditional methods of monolith polymerization employing free radical polymerization mechanisms have yielded good performance but lack the ability to demonstrate repeatable selectivity and sensitivity. Thin films have been deemed to be more useful in sensing applications, but may not offer the right throughput for separations applications. Engineering optimized materials require not only adapting to new chemistries but also knowing their structure-property relationships.     

Radiolabelling with short‐lived PET (positron emission tomography) isotopes using microfluidic reactors

This mini‐review covers the issues concerning the application of microfluidics towards radiolabelling with short‐lived isotopes used for PET (positron emission tomography), and surveys the literature in this area. The application of microfluidic reactors to radiolabelling reactions is currently receiving a great deal of interest because of the potential advantages they have over conventional labelling systems. The volume and variety of radiolabelling reactions for PET is expected to grow markedly over the coming years due to increased demands for PET scanning. High demands and expectations for radiolabelled compounds will have to be met by exploiting new types of chemistry and technologies, such as microfluidics, to improve the production and development of PET tracers. Copyright © 2008 Society of Chemical Industry     

微流控技术可控制备异形微颗粒功能材料的研究进展

异形功能性微颗粒由于具有独特的散射、流变和凝结等特性,被广泛应用于工业和临床医学等领域。微流控技术作为一种新兴的微流体操控技术,能够连续可控地制备尺寸均一、结构和功能多样化的微尺度材料。近年来,利用微流控技术制备异形功能微颗粒成为研究热点。主要综述了利用微流控技术制备多面体结构、棒条状、子弹形、多腔室结构、孔-壳形和螺旋形微颗粒功能材料的研究新进展,重点介绍了基于微流控通道的尺寸和形状的限制作用、基于微流控构建层流模板的可控光刻蚀、基于表面活性剂的种类或含量辅助诱导多重乳液反浸润过程和对利用微流控技术制备的单分散液滴进行二次操作制备异形微颗粒功能材料等方面的研究现状。     

Green microfluidics in microchemical engineering for carbon neutrality

The concept of “carbon neutrality” poses a huge challenge for chemical engineering and brings great opportunities for boosting the development of novel technologies to realize carbon offsetting and reduce carbon emissions. Developing high-efficient, low-cost, energy-efficient and eco-friendly microfluidic-based microchemical engineering is of great significance. Such kind of “green microfluidics” can reduce carbon emissions from the source of raw materials and facilitate controllable and intensified microchemical engineering processes, which represents the new power for the transformation and upgrading of chemical engineering industry. Here, a brief review of green microfluidics for achieving carbon neutral microchemical engineering is presented, with specific discussions about the characteristics and feasibility of applying green microfluidics in realizing carbon neutrality. Development of green microfluidic systems are categorized and reviewed, including the construction of microfluidic devices by bio-based substrate materials and by low carbon fabrication methods, and the use of more biocompatible and non-destructive fluidic systems such as aqueous two-phase systems (ATPSs). Moreover, low carbon applications benefit from green microfluidics are summarized, ranging from separation and purification of biomolecules, high-throughput screening of chemicals and drugs, rapid and cost-effective detections, to synthesis of fine chemicals and novel materials. Finally, challenges and perspectives for further advancing green microfluidics in microchemical engineering for carbon neutrality are proposed and discussed.     

Phenolic resins—100 years of progress and their future

Phenolic resins have been under continuous development as an important thermosetting resin material since the first successful trial production of the synthetic resin in Japan in 1911. Sumitomo Bakelite Co., Ltd. traces its origin to the birth of this material (i.e. the successful trial production) and has been developing synthetic and composite production technologies since that time for adaptation to various applications. Phenolic resin molding compounds, which have been among the major applications of phenolic resins since their inception, exhibit highly favorable characteristics in terms of strength, heat-resistance, long-term reliability and cost, and therefore have been used in a wide range of applications from kitchen parts to components for electronic appliances and automobiles. In particular, phenolic resin molding compounds are gathering attention as a lightweight solution to replace metals in automotive applications, among others applications, and we are investigating these applications while making a vigorous research effort toward further improving the mechanical properties of these materials. This new research and development is founded on detailed prediction and analysis of the hardened structures in phenolic resins.This report outlines the history of phenolic resins, which were invented in 1907 and brought to Japan, along with the associated technology, as a result of personal ties between Dr. Leo Hendrik Baekeland and Dr. Jokichi Takamine; the widening application of phenolic resins in recent years; showcase applications based on green sustainable chemistry; and examples of new analysis methods (chemical analysis) and structural analysis. We hope this report will encourage the research and development of plastics in the new century and the development of commercial products [1].     

Recent Advances of DNA Tetrahedra for Therapeutic Delivery and Biosensing

The chemical and self-assembly properties of nucleic acids make them ideal for the construction of discrete structures and stimuli-responsive devices for a diverse array of applications. Amongst the various three-dimensional assemblies, DNA tetrahedra are of particular interest, as these structures have been shown to be readily taken up by the cell, by the process of caveolin-mediated endocytosis, without the need for transfection agents. Moreover, these structures can be readily modified with a diverse range of pendant groups to confer greater functionality. This minireview highlights recent advances related to applications of this interesting DNA structure including the delivery of therapeutic agents ranging from small molecules to oligonucleotides in addition to its use for sensing and imaging various species within the cell.     

Porous polymer particles—A comprehensive guide to synthesis, characterization, functionalization and applications

This review is written to fulfill the need of a comprehensive guide for the manufacture of porous polymer particles. The synthesis section discusses and for the first time compares microfluidics, membrane/microchannel, suspension, dispersion, precipitation, multistage polymerizations and a few other less known methods, microfluidics being in greater detail. The comparison includes on one hand simplicity, scaling-up possibilities and the ability to yield nonspherical particles for these methods and on the other hand size, size monodispersity, pore characteristics and chemical functionality of the obtained particles. This extensive comparison certainly makes this review also useful for the preparation of nonporous particles. In addition, functionalization/characterization techniques and applications of porous particles are also discussed, including some visionary recommendations. The review is expected not only to enable individual experts of each field to compare their methods with the other ones, but also to be a handbook for the newcomers to this field to guide them from the synthesis to the applications.     

Formation mechanisms and electrical properties of perovskite mesocrystals

Mesocrystals are oriented polycrystals with superstructures consisting of crystallographically ordered nanocrystals. They usually show the electron diffraction behaviour of a single crystal owing to the high order of the nanoscale building units. Mesocrystals have potential applications in many processes such as catalysis, sensing, energy storage and conversion. Perovskite mesocrystals are a novel class of mesocrystalline dielectric nanomaterials that exhibit synergistic properties and anomalous electrical properties; so they have been extensively studied in various fields. This review investigates the chemical formation processes, formation mechanisms and mechanisms that affect performance of perovskite mesocrystals. Moreover, the formation mechanisms of perovskite mesocrystals, namely topochemical mesocrystal conversion mechanism is discussed. Understanding and application of these mechanisms are important for the design and preparation of advanced structural and functional materials. Most importantly, mesocrystal-derived functional materials can be designed by combining orientation, strain, and domain engineering. The potential applications of perovskite mesocrystals as structural and functional materials in piezoelectric, ferroelectric, dielectric, and catalytic devices as well as perovskite solar cells are discussed. This investigation not only develops the chemistry of mesocrystals and proposes new routes for the design of oriented film and ceramic materials, but also provides theoretical support for future applications of perovskite mesocrystals in material science.     

Extracellular Vesicles as a Therapeutic Tool for Kidney Disease: Current Advances and Perspectives

Extracellular vesicles (EVs) have been described as important mediators of cell communication, regulating several physiological processes, including tissue recovery and regeneration. In the kidneys, EVs derived from stem cells have been shown to support tissue recovery in diverse disease models and have been considered an interesting alternative to cell therapy. For this purpose, however, several challenges remain to be overcome, such as the requirement of a high number of EVs for human therapy and the need for optimization of techniques for their isolation and characterization. Moreover, the kidney’s complexity and the pathological process to be treated require that EVs present a heterogeneous group of molecules to be delivered. In this review, we discuss the recent advances in the use of EVs as a therapeutic tool for kidney diseases. Moreover, we give an overview of the new technologies applied to improve EVs’ efficacy, such as novel methods of EV production and isolation by means of bioreactors and microfluidics, bioengineering the EV content and the use of alternative cell sources, including kidney organoids, to support their transfer to clinical applications.     

One-dimensional self-assembly of planar pi-conjugated molecules: adaptable building blocks for organic nanodevices

In general, fabrication of well-defined organic nanowires or nanobelts with controllable size and morphology is not as advanced as for their inorganic counterparts. Whereas inorganic nanowires are widely exploited in optoelectronic nanodevices, there remains considerable untapped potential in the one-dimensional (1D) organic materials. This Account describes our recent progress and discoveries in the field of 1D self-assembly of planar pi-conjugated molecules and their application in various nanodevices including the optical and electrical sensors. The Account is aimed at providing new insights into how to combine elements of molecular design and engineering with materials fabrication to achieve properties and functions that are desirable for nanoscale optoelectronic applications. The goal of our research program is to advance the knowledge and develop a deeper understanding in the frontier area of 1D organic nanomaterials, for which several basic questions will be addressed: (1) How can one control and optimize the molecular arrangement by modifying the molecular structure? (2) What processing factors affect self-assembly and the final morphology of the fabricated nanomaterials; how can these factors be controlled to achieve the desired 1D nanomaterials, for example, nanowires or nanobelts? (3) How do the optoelectronic properties (e.g., emission, exciton migration, and charge transport) of the assembled materials depend on the molecular arrangement and the intermolecular interactions? (4) How can the inherent optoelectronic properties of the nanomaterials be correlated with applications in sensing, switching, and other types of optoelectronic devices? The results presented demonstrate the feasibility of controlling the morphology and molecular organization of 1D organic nanomaterials. Two types of molecules have been employed to explore the 1D self-assembly and the application in optoelectronic sensing: one is perylene tetracarboxylic diimide (PTCDI, n-type) and the other is arylene ethynylene macrocycle (AEM, p-type). The materials described in this project are uniquely multifunctional, combining the properties of nanoporosity, efficient exciton migration and charge transport, and strong interfacial interaction with the guest (target) molecules. We see this combination as enabling a range of important technological applications that demand tightly coupled interaction between matter, photons, and charge. Such applications may include optical sensing, electrical sensing, and polarized emission. Particularly, the well-defined nanowires fabricated in this study represent unique systems for investigating the dimensional confinement of the optoelectronic properties of organic semiconductors, such as linearly polarized emission, dimensionally confined exciton migration, and optimal pi-electronic coupling (favorable for charge transport). Combination of these properties will make the 1D self-assembly ideal for many orientation-sensitive applications, such as polarized light-emitting diodes and flat panel displays.     

Development of microfluidic devices for biomedical and clinical application

This review focuses on the development and use of microfluidic devices within a clinical setting. The underlying theoretical background of microfluidics is briefly elucidated. The materials and techniques used to fabricate the devices and their applicability to the clinical environment are described. The current research in this area is appraised and projections for future applications are discussed. Copyright © 2010 Society of Chemical Industry     

Lipid Nanotechnology

Nanotechnology is a multidisciplinary field that covers a vast and diverse array of devices and machines derived from engineering, physics, materials science, chemistry and biology. These devices have found applications in biomedical sciences, such as targeted drug delivery, bio-imaging, sensing and diagnosis of pathologies at early stages. In these applications, nano-devices typically interface with the plasma membrane of cells. On the other hand, naturally occurring nanostructures in biology have been a source of inspiration for new nanotechnological designs and hybrid nanostructures made of biological and non-biological, organic and inorganic building blocks. Lipids, with their amphiphilicity, diversity of head and tail chemistry, and antifouling properties that block nonspecific binding to lipid-coated surfaces, provide a powerful toolbox for nanotechnology. This review discusses the progress in the emerging field of lipid nanotechnology.     

Evaluation of the electron transport chain inhibition and uncoupling of mitochondrial bioelectrocatalysis with antibiotics and nitro-based compounds

Mitochondrial bioelectrocatalysis can be useful for sensing applications due to the unique metabolic pathways than can be selectively inhibited and uncoupled in mitochondria. This paper details the comparison of different inhibitors and nitro-containing explosive uncouplers in a mitochondria-catalyzed biofuel cell for self-powered explosive sensing. Previous research has reported inhibition of pyruvate oxidation at a mitochondria-modified electrode followed by nitroaromatic uncoupling of current and power. We have previously used oligomycin as the antibiotic and nitrobenzene as the uncoupler of the membrane in the mitochondria-catalyzed biofuel cell, but no comprehensive comparison of various mitochondria inhibitors or explosives has been performed. Results are discussed here for inhibitors targeting complex I, complex III, ATP synthases, adenine nucleotide transport and monocarboxylic acid transport. Reactivation with nitrobenzene was possible in the presence of these inhibitors: oligomycin, 3,3′-diindolylmethane, atractyloside, rotenone, α-cyano-4-hydroxy cinnamic acid and antimycin A. All eleven explosives studied, including: 2,4,6-trinitrotoluene (TNT) and 1,3,5-trinitroperhydro-1,3,5-triazine (RDX), caused uncoupling of the mitochondria function and could be detected by the biosensor.