Microfluidic Synthesis of pH‐Sensitive Multicompartmental Microparticles for Multimodulated Drug Release

Stimuli‐responsive carriers releasing multiple drugs have been researched for synergistic combinatorial cancer treatment with reduced side‐effects. However, previously used drug carriers have limitations in encapsulating multiple drug components in a single carrier and releasing each drug independently. In this work, pH‐sensitive, multimodulated, anisotropic drug carrier particles are synthesized using an acid‐cleavable polymer and stop‐flow lithography. The particles exhibit a faster drug release rate at the acidic pH of tumors than at physiological pH, demonstrating their potential for tumor‐selective drug release. The drug release rate of the particles can be adjusted by controlling the monomer composition. To accomplish multimodulated drug release, multicompartmental particles are synthesized. The drug release profile of each compartment is programmed by tailoring the monomer composition. These pH‐sensitive, multicompartmental particles are promising drug carriers enabling tumor‐selective and multimodulated release of multiple drugs for synergistic combination cancer therapy.     

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.     

Faithful Fabrication of Biocompatible Multicompartmental Memomicrospheres for Digitally Color‐Tunable Barcoding

Barcodes have attracted widespread attention, especially for the multiplexed bioassays and anti‐counterfeiting used toward medical and biomedical applications. An enabling gas‐shearing approach is presented for generating 10‐faced microspherical barcodes with precise control over the properties of each compartment. As such, the color of each compartment could be programmatically adjusted in the 10‐faced memomicrospheres by using pregel solutions containing different combinations of fluorescent nanoparticles. During the process, three primary colors (red, green, and blue) are adopted to obtain up to seven merged fluorescent colors for constituting a large amount of coding as well as a magnetic compartment, capable of effective and robust high‐throughput information‐storage. More importantly, by using the biocompatible sodium alginate to construct the multicolor microspherical barcodes, the proposed technology is likely to advance the fields of food and pharmaceutics anti‐counterfeiting. These remarkable properties point to the potential value of gas‐shearing in engineering microspherical barcodes for biomedical applications in the future.     

A Polymer Microfluidic Chip With Interdigitated Electrodes Arrays for Simultaneous Dielectrophoretic Manipulation and Impedimetric Detection of Microparticles

This paper presents the design, fabrication, and characterization of a polymer microfluidic biochip with integrated interdigitated electrodes arrays (IDAs) used to simultaneously separate, manipulate, and detect microparticles using dielectrophoresis (DEP) and electrochemical impedance spectroscopy (EIS) methods. The DEP response of silica microspheres has been characterized, and microspheres of different sizes (1.8 and 3.5 in diameter) have been DEP flow separated and individually trapped in different microchambers by IDAs in a single run. Simultaneously, the impedance change caused by microspheres captured on IDAs has been analyzed for quantification. High-throughput polymer microfabrication techniques such as micro injection molding were used in this work, so that the polymer microfluidic chip can be produced in a low-cost, disposable platform. This low-cost microfluidic chip provides a generic platform for developing multifunctional lab-on-a-chip devices that require the ability to handle and sense microparticles.     

果蔬包装用可生物降解材料的制备与应用研究进展

目的 可生物降解材料具有高效和环保的特点,可以减轻传统石油基材料过度使用带来的环境污染问题,总结可生物降解材料及其制备技术的特点为进一步促进其在果蔬包装中的应用提供参考和基础。方法 首先对现有的可生物降解材料进行分类,其次探究其制备方法,然后对近年来可生物降解材料在生鲜果蔬包装中的应用,以及对生鲜果蔬保质期和质量的影响相关的研究进行总结和分析,最后对可生物降解材料的特点和应用前景进行归纳、分析和展望。结果 可生物降解材料具有良好的性能,适当的透气性和透湿性,较高的CO2/O2选择透过性,可大幅度地提高果蔬的货架期。结论 可生物降解材料相较于现有的保鲜包装材料有更好的保鲜效果,高效环保,能减轻不可降解材料对环境造成的污染问题。     

A Biodegradable and Stretchable Protein‐Based Sensor as Artificial Electronic Skin for Human Motion Detection

Due to the natural biodegradability and biocompatibility, silk fibroin (SF) is one of the ideal platforms for on‐skin and implantable electronic devices. However, the development of SF‐based electronics is still at a preliminary stage due to the SF film intrinsic brittleness as well as the solubility in water, which prevent the fabrication of SF‐based electronics through traditional techniques. In this article, a flexible and stretchable silver nanofibers (Ag NFs)/SF based electrode is synthesized through water‐free procedures, which demonstrates outstanding performance, i.e., low sheet resistance (10.5 Ω sq^?1), high transmittance (>90%), excellent stability even after bending cycles >2200 times, and good extensibility (>60% stretching). In addition, on the basis of such advanced (Ag NFs)/SF electrode, a flexible and tactile sensor is further fabricated, which can simultaneously detect pressure and strain signals with a large monitoring window (35 Pa–700 kPa). Besides, this sensor is air‐permeable and inflammation‐free, so that it can be directly laminated onto human skins for long‐term health monitoring. Considering the biodegradable and skin‐comfortable features, this sensor may become promising to find potential applications in on‐skin or implantable health‐monitoring devices.     

基于AHPSO-SVM的农产品冷链物流质量安全预警模型

目的为了实时监测农产品始终处于低温、适宜湿度等条件下,实现农产品质量信息的及时反馈和预警。方法针对农产品在冷链物流中的质量安全问题,首先分析影响其质量安全的因素,整合供应链上的追溯信息和监测信息,构建农产品的质量安全预警指标体系。然后设计结合交叉变异算子的自适应混合粒子群算法(AHPSO)优化支持向量机(SVM)参数,以此建立基于AHPSO-SVM的农产品冷链物流质量安全预警模型。结果以苹果的预警指标体系为例,经过模型训练和预测后,预测输出曲线与期望输出曲线均能较好拟合,误差值小。结论该方法较传统的BP神经网络与支持向量机方法,在解决实际问题中预测结果精度更高,可以有效提高农产品冷链物流中质量安全预警的准确性。     

基于我国缺陷汽车产品问卷调查的路径设计与研究

本文基于缺陷汽车产品召回过程及内容,从缺陷汽车的线索征集、召回过程监督,召回完成后的成效等几个方面设计问卷调查,在召回全链条中应用问卷调查来辅助车主缺陷信息问题发生率的判别,监督召回实施过程中的进度及问题,对召回完成率及效果进行验证评估,通过问卷调查方式,快速获得真实有效的信息,在召回工作中提供重要的数据支持.     

Scallop‐Inspired Shell Engineering of Microparticles for Stable and High Volumetric Capacity Battery Anodes

Building stable and efficient electron and ion transport pathways are critically important for energy storage electrode materials and systems. Herein, a scallop‐inspired shell engineering strategy is proposed and demonstrated to confine high volume change silicon microparticles toward the construction of stable and high volumetric capacity binder‐free lithium battery anodes. As for each silicon microparticle, the methodology involves an inner sealed but adaptable overlapped graphene shell, and an outer open hollow shell consisting of interconnected reduced graphene oxide, mimicking the scallop structure. The inner closed shell enables simultaneous stabilization of the interfaces of silicon with both carbon and electrolyte, substantially facilitates efficient and rapid transport of both electrons and lithium ions from/to silicon, the outer open hollow shell creates stable and robust transport paths of both electrons and lithium ions throughout the electrode without any sophisticated additives. The resultant self‐supported electrode has achieved stable cycling with rapidly increased coulombic efficiency in the early stage, superior rate capability, and remarkably high volumetric capacity upon a facile pressing process. The rational design and engineering of graphene shells of the silicon microparticles developed can provide guidance for the development of a wide range of other high capacity but large volume change electrochemically active materials.