Synthesis and Characterization of Polymer Brushes on Micromechanical Cantilevers

Summary: A technique to cover microelectromechanical systems (MEMS), such as micromechanical cantilever (MC) sensors, with a covalently bound brush layer has been developed. The polymer layer was grown using a “grafting‐from” synthesis of polymer brushes under mild conditions, by surface‐initiated atom transfer radical polymerization. Atomic force microscopy (AFM) and ellipsometry have revealed a uniform thickness of about 12 nm from which a grafting density of polymer brushes of 0.19 chains · nm^?2 was estimated. The coating with polymer brushes can be realized on a selected surface. It was shown that a single‐sided brush layer swells reversibly in toluene, resulting in a bending of the micromechanical cantilever.

Schematic representation of the PMMA brush synthesis on the MC surface, by surface‐initiated ATRP.     

用于人体药物吸收研究的定点释放药丸系统研制

定点释放药丸系统是一种基于微型机械电子系统(MEMs)的工程药丸，无创地实现了消化道内定点药物释放。人体药物吸收(Human Drug Absorption，HDA)研究是新药开发过程中获得药物吸收路线图的重要手段，定点释放药丸系统是HDA研究的重要工具。本研究开发了一种新型的定点释放药丸系统，并开发了基于磁标记跟踪技术的定位跟踪系统，该定点释放药丸系统具有使用方便、效率高、适应多种药物剂型的优点，该系统也为中药药理学研究提供了一种新的手段，具有良好的应用前景。     

Automatic microfluidic platform for cell separation and nucleus collection

This study reports a new biochip capable of cell separation and nucleus collection utilizing dielectrophoresis (DEP) forces in a microfluidic system comprising of micropumps and microvalves, operating in an automatic format. DEP forces operated at a low voltage (15 V_p–p) and at a specific frequency (16 MHz) can be used to separate cells in a continuous flow, which can be subsequently collected. In order to transport the cell samples continuously, a serpentine-shape (S-shape) pneumatic micropump device was constructed onto the chip device to drive the samples flow through the microchannel, which was activated by the pressurized air injection. The mixed cell samples were first injected into an inlet reservoir and driven through the DEP electrodes to separate specific samples. Finally, separated cell samples were collected individually in two outlet reservoirs controlled by microvalves. With the same operation principle, the nucleus of the specific cells can be collected after the cell lysis procedure. The pumping rate of the micropump was measured to be 39.8 μl/min at a pressure of 25 psi and a driving frequency of 28 Hz. For the cell separation process, the initial flow rate was 3 μl/min provided by the micropump. A throughput of 240 cells/min can be obtained by using the developed device. The DEP electrode array, microchannels, micropumps and microvalves are integrated on a microfluidic chip using micro-electro-mechanical-systems (MEMS) technology to perform several crucial procedures including cell transportation, separation and collection. The dimensions of the integrated chip device were measured to be 6 × 7 cm. By integrating an S-shape pump and pneumatic microvalves, different cells are automatically transported in the microchannel, separated by the DEP forces, and finally sorted to specific chambers. Experimental data show that viable and non-viable cells (human lung cancer cell, A549-luc-C8) can be successfully separated and collected using the developed microfluidic platform. The separation accuracy, depending on the DEP operating mode used, of the viable and non-viable cells are measured to be 84 and 81%, respectively. In addition, after cell lysis, the nucleus can be also collected using a similar scheme. The developed automatic microfluidic platform is useful for extracting nuclear proteins from living cells. The extracted nuclear proteins are ready for nuclear binding assays or the study of nuclear proteins.     

基于电热型扫描微镜的微型双光子显微镜探头设计

双光子荧光显微镜的微型化对在体脑部神经活动研究和体内组织病理状态检测具有非常重要意义。本文设计了一种基于电热型扫描微镜的微型化双光子荧光显微镜探头,其微镜设计采用反向串联双S型双层材料结构,通过对微镜四个侧面执行器分别施加周期信号,实现了±3.5°的扫描范围;其光学设计是通过单模光纤导入800 nm飞秒激光,激光经微镜扫描,由光学系统聚焦作用于生物样品,激发样品产生荧光,荧光信号通过采集光路汇集并耦合到多模光纤输出,最后通过显微镜的图像采集系统成像。探头尺寸为26 mm(L)×12 mm(W)×8 mm(H),重量为5.6 g。利用该显微镜探头,对含有不同尺寸凹槽的微结构进行了成像测试,其结果表明,其扫描成像的范围可以实现150μm×150μm,横向分辨率可达到5μm;利用该探头对荧光染色小鼠肾脏冷冻切片进行的成像测试,成功得到了双光子二维荧光图像。基于本装置以及进一步的改进,将有助于构建便携式双光子荧光显微镜,置于活体动物头部,在体进行脑部神经活动研究。     

微系统在临床医疗中的应用现状与发展趋势

微系统是随着微电子、微机械等技术的发展而诞生的新兴技术,在航空、航天、军事、医学等领域应用前景广阔。简要介绍了微系统技术的基本原理、性能特点、应用范围,重点描述了智能胶囊消化道内窥镜系统、人体腔道生理参数检测微系统、人体消化道施药诊疗微系统、微胶囊基因分析和遗传诊断等微系统在临床医疗工作中的应用状况以及发展趋势。     

New pressure sensing elements for FFR coronary catheter

The next generation FFR Coronary Catheter includes a new stable pressure sensor, AD conversion at the tip of the catheter and mount of these components on the sidewall of the catheter instead of the guide wire enabling thus to use standard guide wires. The new ultrathin capacitive MEMS pressure sensor die with corresponding readout ASIC circuit offers better accuracy, robustness and automated assembly. The measured performance values of the fabricated chips correlate well with the simulated ones indicating comprehensive understanding of the sensor operation and control of the fabrication process. The test measurements outperformed the specifications for the FFR pressure sensing.     

Integrated design of MEMS: aiming at manufacturability

This paper is a first attempt to qualify the design process in the field of MEMS product. Through this study, we try to analyse how the issue of manufacturability is addressed in a context of integrated design. This implies to understand specificities of the manufacturing process involved in the realization of these products (we focus on process derived from VLSI industry). Then we look at the main current design methodologies to understand how the manufacturing is being taken into account. Computer aided tools associated to these methodologies are presented at the same time. Finally, we conclude on the need of specifications for a design methodology that would provide designers with greater independence from manufacturing constraints.     

基于MEMS技术的红细胞变形性测量系统的研究

利用MEMS技术加工具有特殊材料和结构的微通道阵列模拟毛细血管网络，从而实现了一种新的基于硅基微通道的红细胞流变学测量芯片系统的研究，整个系统具有血液流过数据（图像、流速、流过参数等）的实时采集与分析功能。系统结合相关学科的先进性，有助于医疗、生化等领域的科学研究的广泛应用前景。     

Comparison of Adherence to Glimepiride/Metformin Sustained Release Once-daily Versus Glimepiride/Metformin Immediate Release BID Fixed-combination Therapy Using the Medication Event Monitoring System in Patients With Type 2 Diabetes

Purpose

The purpose of this study was to compare the adherence of the glimepiride/metformin sustained release (GM-SR) once-daily fixed-dose combination and glimepiride/metformin immediate release (GM-IR) BID fixed-dose combination in type 2 diabetes therapies.