细胞电融合芯片技术的发展及展望

细胞电融合芯片技术是最近十几年来发展迅速的一种细胞融合方法,它可以广泛用于遗传学、动植物远缘杂交育种、发育生物学、免疫学、医药、食品以及农业等领域的基础研究和应用开发。由于其不仅具有可控性强、操作简便、对细胞无毒害等优点,还比传统细胞电融合技术更安全、快捷、高效、便携、集成度高,而且便于实验观察,样本消耗少,因此,在国内外广受关注。本文综述了细胞电融合芯片技术的基本原理、实现方法、研究进展,并对其未来发展作了展望。     

Mathematical modelling of chip thickness in micro-end- milling: A Fourier modelling

This study developed a model of undeformed chip thickness in micro-end-milling for the use in estimating cutting constants based on measured cutting forces. The proposed estimation method is based upon the invertibility of the average milling force model. In this paper, chip thickness in micro-end-milling was estimated by summing the thicknesses of the conventional chip component and the additional chip component. Thickness was then expressed in terms of Fourier series. The analyses showed that the fast convergence of Fourier series gives the Fourier chip thickness model sufficient accuracy when using only five terms of the truncated Fourier series for common micro-end-milling processes. The Fourier coefficients can be expressed in terms of the ratio of feed per tooth to cutter radius for different numbers of cutter teeth. The accuracy and conciseness of the chip thickness model enables the modelling of average cutting force in a closed form, which can be applied to identify the cutting constants. Cutting force experiments verify that the model prediction agrees very well with the experimental results.     

基于微流控芯片的电解质溶液太赫兹吸收特性研究

由于许多生物分子的振动和转动能级均在太赫兹波段,且太赫兹波具有电子能量低（约4 meV）,不会破坏待测样品的特性,因此可以采用太赫兹光谱技术检测生物样品。然而许多生物分子在液体环境中才能保持其生物活性,需要在盐溶液中来探究酸碱环境对其的影响,以及在盐类缓冲液中研究其生物特性。但水作为极性液体对太赫兹波有强烈的吸收,因此,探究如何减少水对太赫兹吸收的方法非常必要。水对太赫兹的吸收主要因水分子间氢键造成,现阶段最常见的方法是减少水与太赫兹波的作用距离以及破坏水分子间的氢键。利用夹心式微流控芯片在太赫兹时域光谱系统下通过观察光谱强度变化来探究电解质对水分子间氢键的影响,既减少了水和太赫兹波的作用距离,又探究了电解质对水分子间氢键的作用。在微流控芯片中分别加入不同种类以及不同浓度的电解质,通过观察其在0.1～1.0 THz范围内的光谱强度变化来分析不同电解质对水分子间氢键的影响。部分电解质促进氢键的缔合,而另一部分则破坏氢键的形成,在太赫兹光谱范围内表现为光谱强度的变化。若促进氢键的缔合则对太赫兹吸收变大,光谱强度减弱;若破坏氢键的缔合则对太赫兹吸收减弱,光谱强度增加。研究结果发现：在水中加入KCl和KBr时,太赫兹光谱强度增加,表明二者对氢键有破坏作用,使得光谱强度变大;然而当加入MgCl₂和CaCl₂时,太赫兹光谱强度减弱,表明二者对氢键有缔合作用,从而使光谱强度变小。利用太赫兹技术在0.1～1.0 THz范围内研究KCl,KBr,MgCl₂和CaCl₂这四种不同浓度的电解质溶液特性,发现它们只会对光谱强度造成一定影响,不会引入新的特征吸收峰以及对待测样品造成干扰。这对于研究诸如大肠杆菌、枯草芽孢杆菌等在0.1～1.0 THz范围内有特征吸收谱的生物分子具有一定的实用价值。在溶液中加入所需的电解质并借助微流控芯片不仅可以识别待测样品、研究待测样品的光谱信息、探究其生物特性,而且为进一步推动太赫兹技术在生化方面的应用研究提供了先决条件。     

数字化温湿度采集仪的研制

在日常生产活动中,很多场合需要进行温度、湿度测量。为了达到对温湿度的精确测量,设计并实现了一种数字化温湿度采集仪。该采集仪以89S52单片机为核心,具有温湿度采集范围广、精度高、抗干扰能力强、接口丰富、使用灵活等优点。采集仪既可以作为单机仪器,也可以通过RS485组成网络化测试系统。作为单机仪器时,有大屏幕的LCD(128*64)显示实时的温、湿度和露点温度。通过对现场试验测试并对结果进行分析,表明该采集仪完全满足测量要求,有较高的使用价值。     

电场耦合法芯片电泳柱上电导检测特性研究

通过电场耦合作用对毛细管电泳柱上直流电导检测原理进行了分析, 利用带有双T结构检测池的玻璃和聚合物芯片对其特性进行了研究. 在电泳分离过程中, 电泳高电场通过检测通道耦合到出口的检测电极上并产生可被检测的电势差. 当导电性与支持电解质不同的组分谱带通过分离通道上的检测池时造成该电位差的变化, 该变化与溶液电导率、检测池长度和电场强度直接相关. 检测信号与基线相除得到的信号只和检测池中溶液的物理特征参数(电导率及电阻)有关. 用自制高阻抗信号转换系统可使芯片电泳电场强度提高到450 V/cm以上, 以1 mmol/L Tris-HCl为支持电解质, 在12 s内实现了K＋和Na＋的高重现性分离检测, 检出限达到5 μmol/L, 线性范围达两个数量级(10 μmol/L~2 mmol/L).     

Enzyme-catalyzed amperometric oxidation of neurotransmitters in chip-capillary electrophoresis

The determination of biogenic monoamines by enzyme-catalyzed oxidation after electrophoretical separation on a microfluidic chip decreases their detection limits significantly. An amperometric system with a chemically amplified response for neurotransmitters and their metabolites is presented. The principle is the rapid cyclic oxidation of the analyte on the amperometric detector in the presence of the redoxactive enzyme glucose oxidase in the capillary electrophoresis buffer. With this approach, detection limits in the range of 10(-7)-10(-8) M could be reached. Because of the good linearity between the current response and the concentration of catecholamines and their metabolites at concentrations up to 300 microM, this method is attractive for the analytical detection at low concentration levels such as in biological fluids.     

A Magnetically Driven Tandem Chip Enables Rapid Isolation and Multiplexed Profiling of Extracellular Vesicles

The protein phenotypes of extracellular vesicles (EVs) have emerged as promising biomarkers for cancer diagnosis and treatment monitoring. However, the technical challenges in rapid isolation and multiplexed molecular detection of EVs have limited their clinical practice. Herein, we developed a magnetically driven tandem chip to achieve streamlined rapid isolation and multiplexed profiling of surface protein biomarkers of EVs. Driven by magnetic force, the magnetic nanomixers not only act as tiny stir bars to promote mass transfer and enhance reaction efficiency of EVs, but also transport on communicating vessels of the tandem chip continuously and expedite the assay workflow. We designed cyclic surface enhancement of Raman scattering (SERS) tags to bind with target EVs and then release them by exonuclease I, eliminating steric hindrance and amplifying the SERS signal of multiple protein biomarkers on EVs. Due to the excellent assay performance, six breast cancer biomarkers were detected simultaneously on EVs using only 10 μL plasma within 1.5 h. The unweighted SUM signature offers great accuracy in discriminating breast cancer patients from healthy donors. Overall, the dynamic magnetic driving tandem chip offers a new avenue to advance the clinical application of EV-based liquid biopsy.     

微流控PCR芯片的研究进展

基因是人类的遗传密码,人类个体之间只有万分之一的基因不相同,却导致了人与人之间丰富的差异.了解这种差异对于科学研究具有巨大的应用价值.PCR是基因研究中常用的手段之一,但传统PCR仪存在反应时间长、能量消耗大、不便于集成与携带等缺陷,微流控技术与PCR结合可以有效缩小反应体系,提高反应效率,且易于集成化与微型化.本文按照微流控PCR芯片的结构分类,详细介绍了微池型、连续流动型PCR芯片,以及电泳、荧光、电化学和DNA杂交阵列等检测方法,并在最后进行了总结与展望.     

芯片式流通池用于顺序注射可更新表面荧光免疫法测定人血清中的IgG

采用芯片式流通池作为非均相免疫反应和原位固相荧光检测的场所,用双岔光纤将芯片式流通池与荧光光度计耦联,以双抗夹心式非均相免疫反应的模式,研究建立了测定人血清中IgG的顺序注射可更新表面非均相免疫分析新方法.