膜乳化法制备单分散高分子微球和微囊的研究进展

膜乳化法不仅是获得高质量单分散稳定乳液的一种简单有效方法，也是制备单分散功能性微球和微囊的有效手段．着重介绍了用膜乳化法制备单分散药物载体微球和微囊、色谱柱填料微球和电子摄影调色剂微球，以及其它单分散高分子微球和微囊方面的研究成果．     

生物微流控PCR荧光芯片微通道动态检测系统研究

研究和建立了生物微流控PCR荧光芯片微流控微通道动态检测系统,对该系统的多光路光纤校准进行了研究,获得了荧光检测的重复性(偏差:2.6%)和稳定性(偏差》2.7%)等.实验结果表明:该系统可用于准分子激光制备高聚物基生物微流控PCR荧光芯片最佳工艺激光制备参数的优化设计;可用于生物微流控PCR荧光芯片生物分析时的实时荧光定量检测;也可用于对激光荧光检测微型化技术与生物芯片光谱检测集成化提供多功能实验基础和性能评估体系.     

开放式数字微流控驱动器设计、制造与性能评价

基于介质上电润湿(electrowetting-on-dielectric,EWOD)技术的数字微流控技术可以对微量液滴进行灵活操作,近年来日益成为微流控领域的研究热点.本文基于开放式数字微流控驱动器的基本原理,旨在提供器件改进的途径,提出了EWOD器件的性能评价与优化方法.设计制造了不同电极形状的EWOD器件,通过实验对比了不同电极结构的性能,分析了EWOD器件性能改善的内在原因.本文提出的开放式数字微流控驱动器设计思路与评价方法可以为EWOD器件以及基于EWOD技术的数字微流控芯片设计起到指导作用.     

微流控纺丝技术及多元结构微流控纤维柔性可穿戴应用

微流控纺丝技术融合了微流控技术和纺丝技术的优点，可设计制备常规纺丝技术难以实现的复杂结构微纤维。通过对微尺度流体流动的精确调控及利用微通道内流体的层流流动特性，微流控纺丝技术制备的多元结构功能微纤维在生物医学、柔性电子、分析化学等领域具有广泛应用。本文系统介绍了微流控纺丝技术的纺丝装置及固化机制，综述了实心/多孔纤维、中空/核壳纤维、Janus/双组分/多组分纤维、纺锤状纤维、螺旋纤维等多元结构纤维的制备方法、结构特点及其在柔性可穿戴中的应用，最后分析了微流控纺丝技术在制备微纤维中的优势与不足，并对微流控纺丝技术的应用前景进行展望。     

一种自封装技术制备PMMA微流控通道方法研究

本文结合湿法腐蚀技术、紫外固化纳米压印技术、热压纳米压印技术制备出聚甲基丙烯酸甲酯(PMMA)沟槽微结构,基于局部加热的自封装技术成功制备出了PMMA微流控通道。研究了硅模板结构参数的选择要求以及工艺过程中实验参数对实验的影响。实验结果表明,热硅片与基片相对运动方向应与PMMA沟槽微结构方向平行,有利于制备出变形量小、尺寸均匀的微流控通道。     

环烯烃聚合物(COP)微流控芯片的制备及其与聚甲基丙烯酸甲酯(PMMA)微流控芯片的性能对比

采用热压方法制备了环烯烃聚合物(COP)微流控芯片.考虑到温度对微结构热压成形的质量影响最大,基于材料的粘弹性特性,通过变温准蠕变实验获得了热压参考温度Tr.实验证明,在该温度下热压成形,宽度和深度方向的复制精度分别达到了97.6%和94.3%.为了研究制备的COP微流控芯片的性能,将其和同一模具制备的PMMA微流控芯片进行了性能对比实验.通过背景荧光实验、电泳实验和DNA分析实验三方面的研究表明,与PMMA芯片相比,COP芯片背景荧光低,电泳效率高,检测重现性相对标准偏差小于2.5%,适用于生化分析.     

微通道内表面上分布密度可控的ZnO纳米棒阵列的生长

在微流控器件的微通道内表面制备了分布可控的ZnO纳米棒阵列。先利用单分散的反相胶束借助非传统的去乳化作用在玻璃毛细管通道内壁上得到了分散很好的ZnO晶种,随后得到了ZnO纳米棒的花状簇阵列。通过调控微乳体系中的W值（水与表面活性剂的摩尔比值）得到了分散密度不同的晶种,从而在毛细管内壁上制备出了分布密度可控的ZnO纳米棒阵列,为密封的长微通道功能化改性提出了一种新的方法,经该方法改善后,可在微通道内得到纳米尺度下的一维纳米材料的特殊结构,用来设计和构筑功能化、集成化的微流控器件。     

锥管微通道连续相粘度影响的实验研究

微流控指的是使用微通道操纵微小流体的系统所涉及的科学和技术。微流控技术在微通道中可以完成对液滴体积的精确控制、单个液滴的操控、节省原材料、大批量生产单分散液滴等。液液两相流在生物和化学分析方面是一种具有良好应用前景的工具。本文采用共轴微通道结构,设计了α=2. 8°共轴微通道试样,研究微通道中石蜡/乙醇两相流收敛角和两相粘度对流型图、液滴特征直径的影响。     

毛细管微流控芯片器件研究进展EI北大核心CSCD

毛细管微流控芯片是微流控芯片领域中重要的一部分,因其具有制备难度低、材料成本低、化学性能优良以及设计灵活的独特优势而得到了广泛的应用与研究。文中对毛细管微流控芯片的基本工作原理与制作方法进行了详细叙述,重点综述了近年来毛细管微流控芯片在液滴生成、纤维纺丝等领域中的研究进展与应用,最后对目前面临的问题进行了探讨,并展望了该技术未来在标准化、高通量及灵活性等方面应用的发展方向。     

基于3D打印的血型检测微流控芯片研究

3D打印在微流控芯片领域应用广泛,但专门用于血型检测的微流控芯片研究较少。针对该问题,设计制备一种密闭通道的微流控芯片,使其应用于临床,以解决快捷血型检测问题。该文采用基于DLP光固化的3D打印技术,对该芯片进行设计构建。通过图像识别该3D芯片微流道内红细胞停留位置,可在3 min左右完成单样品检测,识别率99.29%,达到快速检测血型的目的。该芯片满足检测要求,能完成试剂和血液的顺序灌装、离心、识别等操作,成本低、检测快,可对不同检测要求进行后期处理,为个性化医疗和移动医疗的快速建设奠定基础,具有一定研究价值。     

pH响应型微囊膜的研究与应用进展

综述了pH响应型微囊膜的研究和应用进展,着重介绍了pH响应型微囊膜的制备与性能方面的研究成果,以及pH响应型微囊膜在结肠靶向式药物送达、蛋白质的控制释放、酶反应的“起／停”控制、脱氮过程pH控制等方面的应用成果．     

Preparation of Monodisperse Biodegradable Polymer Microparticles Using a Microfluidic Flow‐Focusing Device for Controlled Drug Delivery

Degradable microparticles have broad utility as vehicles for drug delivery and form the basis of several therapies approved by the US Food and Drug Administration. Conventional emulsion‐based methods of manufacturing produce particles with a wide range of diameters (and thus kinetics of release) in each batch. This paper describes the fabrication of monodisperse, drug‐loaded microparticles from biodegradable polymers using the microfluidic flow‐focusing (FF) devices and the drug‐delivery properties of those particles. Particles are engineered with defined sizes, ranging from 10 µm to 50 µm. These particles are nearly monodisperse (polydispersity index = 3.9%). A model amphiphilic drug (bupivacaine) is incorporated within the biodegradable matrix of the particles. Kinetic analysis shows that the release of the drug from these monodisperse particles is slower than that from conventional methods of the same average size but a broader distribution of sizes and, most importantly, exhibit a significantly lower initial burst than that observed with conventional particles. The difference in the initial kinetics of drug release is attributed to the uniform distribution of the drug inside the particles generated using the microfluidic methods. These results demonstrate the utility of microfluidic FF for the generation of homogenous systems of particles for the delivery of drugs.     

微流控技术制备吡柔比星聚乳酸微球及其体外释放研究

微流控液滴技术是制备单分散性药物载体的理想方法,对精确考察药物的释放行为、释放机理及动力学模型具有重要意义。采用亲水性修饰T型通道产生单分散性吡柔比星聚乳酸液滴,考察了通道性质对液滴生成的影响以及连续相和分散相流速与液滴尺寸的关系,制备了两种粒径的吡柔比星聚乳酸微球并考察了其体外释放行为。结果表明,经修饰的通道可产生稳定均一的液滴,通过调节两相流速可以有效控制液滴和微球的尺寸,制备的微球粒径均一,载药量和包封率高,吡柔比星体外释放缓慢且无明显突释,尺寸较大微球的释放速率较慢。     

Polymersomes Containing a Hydrogel Network for High Stability and Controlled Release

Capillary microfluidic devices are used to prepare monodisperse polymersomes consisting of a hydrogel core and a bilayer membrane of amphiphilic diblock‐copolymers. To make polymersomes, water‐in‐oil‐in‐water double‐emulsion drops are prepared as templates through single‐step emulsification in a capillary microfluidic device. The amphiphile‐laden middle oil phase of the double‐emulsion drop dewets from the surface of the innermost water drop, which contains hydrogel prepolymers; this dewetting leads to the formation of a bilayer membrane. Subsequently, the oil phase completely separates from the innermost water drop, leaving a polymersome. Upon UV illumination of the polymersome, the prepolymers encapsulated within the interior are crosslinked, forming a hydrogel core. The hydrogel network within the polymersomes facilitates sustained release of the encapsulated materials and increases the stability of the polymersomes through the formation of a scaffold to support the bilayer. In addition, this approach provides a facile method to make monodisperse hydrogel particles directly dispersed in water.     

Droplet‐Based Microfluidic Synthesis of Anisotropic Metal Nanocrystals

A droplet‐based microfluidic method for the preparation of anisotropic gold nanocrystal dispersions is presented. Gold nanoparticle seeds and growth reagents are dispensed into monodisperse picoliter droplets within a microchannel. Confinement within small droplets prevents contact between the growing nanocrystals and the microchannel walls. The critical factors in translating macroscale flask‐based methods to a flow‐based microfluidic method are highlighted and approaches are demonstrated to flexibly fine tune nanoparticle shapes into three broad classes: spheres/spheroids, rods, and extended sharp‐edged structures, thus varying the optical resonances in the visible–near‐infrared (NIR) spectral range.     

Monodisperse, Submicrometer Droplets via Condensation of Microfluidic-Generated Gas Bubbles

Microfluidics (MFs) can produce monodisperse droplets with precise size control. However, the synthesis of monodisperse droplets much smaller than the minimum feature size of the microfluidic device (MFD) remains challenging, thus limiting the production of submicrometer droplets. To overcome the minimum micrometer-scale droplet sizes that can be generated using typical MFDs, the droplet material is heated above its boiling point (bp), and then MFs is used to produce monodisperse micrometer-scale bubbles (MBs) that are easily formed in the size regime where standard MFDs have excellent size control. After MBs are formed, they are cooled, condensing into dramatically smaller droplets that are beyond the size limit achievable using the original MFD, with a size decrease corresponding to the density difference between the gas and liquid phases of the droplet material. Herein, it is shown experimentally that monodisperse, submicrometer droplets of predictable sizes can be condensed from a monodisperse population of MBs as generated by MFs. Using perfluoropentane (PFP) as a representative solvent due to its low bp (29.2 °C), it is demonstrated that monodisperse PFP MBs can be produced at MFD temperatures >3.6 °C above the bp of PFP over a wide range of sizes (i.e., diameters from 2 to 200 μm). Independent of initial size, the generated MBs shrink rapidly in size from about 3 to 0 °C above the bp of PFP, corresponding to a phase change from gas to liquid, after which they shrink more slowly to form fully condensed droplets with diameters 5.0 ± 0.1 times smaller than the initial size of the MBs, even in the submicrometer size regime. This new method is versatile and flexible, and may be applied to any type of low-bp solvent for the manufacture of different submicrometer droplets for which precisely controlled dimensions are required.     

High‐Throughput Continuous Flow Production of Nanoscale Liposomes by Microfluidic Vertical Flow Focusing

Liposomes represent a leading class of nanoparticles for drug delivery. While a variety of techniques for liposome synthesis have been reported that take advantage of microfluidic flow elements to achieve precise control over the size and polydispersity of nanoscale liposomes, with important implications for nanomedicine applications, these methods suffer from extremely limited throughput, making them impractical for large‐scale nanoparticle synthesis. High aspect ratio microfluidic vertical flow focusing is investigated here as a new approach to overcoming the throughput limits of established microfluidic nanoparticle synthesis techniques. Here the vertical flow focusing technique is utilized to generate populations of small, unilamellar, and nearly monodisperse liposomal nanoparticles with exceptionally high production rates and remarkable sample homogeneity. By leveraging this platform, liposomes with modal diameters ranging from 80 to 200 nm are prepared at production rates as high as 1.6 mg min⁻¹ in a simple flow‐through process.     

25th Anniversary Article: Double Emulsion Templated Solid Microcapsules: Mechanics And Controlled Release

How droplet microfluidics can be used to fabricate solid‐shelled microcapsules having precisely controlled release behavior is described. Glass capillary devices enable the production of monodisperse double emulsion drops, which can then be used as templates for microcapsule formation. The exquisite control afforded by microfluidics can be used to tune the compositions and geometrical characteristics of the microcapsules with exceptional precision. The use of this approach to fabricate microcapsules that only release their contents when exposed to a specific stimulus – such as a change in temperature, exposure to light, a change in the chemical environment, or an external stress – only after a prescribed time delay, and at a prescribed rate is reviewed.     

Encoded silica colloidal crystal beads as supports for potential multiplex immunoassay

We developed a new kind of suspension array for multiplexed immunoassays using silica colloidal crystal beads (SCCBs) as coding carriers. The monodisperse and size-controlled SCCBs were fabricated by a microfluidic device. Calcination was employed to improve the mechanical stability and lower the fluorescent background of the SCCBs. Immobilization of protein molecules on the surface of the SCCBs through chemical bonds was studied, and the modification condition was optimized to increase the detection sensitivity. Results indicated that the SCCBs as supports were more sensitive (0.92 ng/mL IgG) than the glass beads (27 ng/mL IgG) and the planar carriers (140 ng/mL IgG). A multiplex immunoassay showed the flexibility and feasibility of SCCBs array in clinical applications.     

A device for the fabrication of multifunctional particles from microbubble suspensions

A novel V-junction microfluidic (VJM) device has been used to generate several types of particles from the break-up of bubbles. The flow rates of selected solutions and the gas pressure were adjusted in order to successfully generate monodisperse polymer coated microbubbles, which serve as a platform for particle generation. Uniform particles in both the nano and micro size ranges with different shapes were spontaneously generated from bubbles and have the potential to be used in several advanced technological applications.