快速、灵敏和特异性地检测病原微生物,在临床诊断和传染病控制中具有重要意义。早期准确检测是快速控制疫区疫情的有效措施,尤其是在缺乏有效治疗和疫苗的情况下。聚合酶链式反应(PCR)作为常用的核酸检测技术和疾病诊断的“金标准”,有...快速、灵敏和特异性地检测病原微生物,在临床诊断和传染病控制中具有重要意义。早期准确检测是快速控制疫区疫情的有效措施,尤其是在缺乏有效治疗和疫苗的情况下。聚合酶链式反应(PCR)作为常用的核酸检测技术和疾病诊断的“金标准”,有着高灵敏度的优势,但同时也存在以牺牲特异性为代价的现象。酶联免疫吸附试验(ELISA)是一种快速、特异性强的蛋白质和小分子诊断工具。然而,灵敏度低和样品预处理复杂的操作步骤极大地限制了该方法现场检测的应用。因此,快速、灵敏和特异性的检测技术成为了急需解决的要点,随着技术的应用和发展,基于CRISPR-Cas的生物传感系统的优异性能在开发病原微生物诊断技术方面引起了人们的关注。本文综述了CRISPR/Cas系统在病原微生物检测的作用机制及原理,总结了新型检测技术的优缺点并对应用发展前景进行展望。Rapid, sensitive, and specific detection of pathogenic microorganisms is crucial for clinical diagnosis and infectious disease control. Early and accurate detection is an effective measure to quickly control epidemic outbreaks, especially in the absence of effective treatments and vaccines. Polymerase Chain Reaction (PCR) is a commonly used nucleic acid testing technology and the “gold standard” for disease diagnosis with high sensitivity. However, it often sacrifices specificity. Enzyme-Linked Immunosorbent Assay (ELISA) is a rapid and highly specific diagnostic tool for proteins and small molecules. Nevertheless, its low sensitivity and complex sample preprocessing steps greatly limit its application in on-site testing. Therefore, the development of rapid, sensitive, and specific detection technologies has become an urgent need. With the application and advancement of technology, the excellent performance of CRISPR-Cas based biosensing systems has attracted attention in the development of pathogenic microorganism diagnostic techniques. This article reviews the mechanisms and principles of CRISPR/Cas systems in pathogenic microorganism detection, summarizes the advantages and disadvantages of novel detection technologies, and provides an outlook on their future applications.展开更多
In this paper, we present a novel design scheme of temperature-jump(T-jump) area for microfluidic device.Numerical simulation and experimental research of thermal characteristics of the solution in microchannels is co...In this paper, we present a novel design scheme of temperature-jump(T-jump) area for microfluidic device.Numerical simulation and experimental research of thermal characteristics of the solution in microchannels is completed.Numerical simulation of the temperature-jump microchannel is analyzed to study the heat transfer characteristics by comparing performance of three proposed configurations.Calculation of the power requirement is discussed in the dimensional design of microheater. Temperature-sensitive fluorescent dye is applied to investigate the temperature field of microchannel heated by a designed microheater. It is found that the T-jump microfluidic device can provide rapid heating for solutions with strong convection heat transfer ability.展开更多
This paper presents the experimental results of liquid-liquid microflows in a coaxial microfluidic device with mass transfer.Three working systems were n-butanol + phosphoric acid(PA) + water,methyl isobutyl ketone(MI...This paper presents the experimental results of liquid-liquid microflows in a coaxial microfluidic device with mass transfer.Three working systems were n-butanol + phosphoric acid(PA) + water,methyl isobutyl ketone(MIBK) + PA + water,30% kerosene in tri-n-butylphosphate(TBP) + PA + water.The direction and intensity of mass transfer were adjusted by adding PA in one of two phases mutual saturated in advance.When PA transferred from the organic phase to the aqueous phase,tiny aqueous droplets may generate inside the organic phase by mass transfer inducement to form a new W/O/W flow pattern directly on some special cases.Once the PA concentration was very high,violent Marangoni effect could be observed to throw part of organic phase out of droplets as tail.The interphase transfer of PA could expand the jetting flow region,in particular for systems with low or medium inter-facial tension and when the mass transfer direction was from the aqueous phase to the organic phase.展开更多
Advanced microfluidic technology was used to examine the microscopic viscous and inertial effects evolution of water flow in rock joints. The influence of void space on fluid flow behaviour in rock joints under differ...Advanced microfluidic technology was used to examine the microscopic viscous and inertial effects evolution of water flow in rock joints. The influence of void space on fluid flow behaviour in rock joints under different flow velocities was experimentally investigated at the micro scale. Using advanced fabrication technology of microfluidic device, micro flow channels of semicircular, triangular, rectangular and pentagonal cavities were fabricated to simulate different void space of rock joints, respectively. Using the fluorescence labelling approach, the trajectory of water flow was captured by the microscope digital camera when it passed over the cavity under different flow velocities. The flow tests show that the flow trajectory deviated towards the inside of the cavity at low flow velocities. With the increase in flow velocity, this degree of flow trajectory deviation decreased until there was no trajectory deviation for flow in the straight parallel channel. The flow trajectory deviation initially reduced from the void corner near the entrance. At the same time, a small eddy appeared near the void corner of the entrance. The size and intensity of the eddy increased with the flow velocity until it occupied the whole cavity domain. The gradual reduction of flow trajectory near the straight parallel channel and the growth of eddy inside the cavity reflect the evolution of microscopic viscous and inertial forces under different flow velocities.The eddy formed inside the cavity does not contribute to the total flow flux, but the running of the eddy consumes flow energy. This amount of pressure loss due to voids could contribute to the nonlinear deviation of fracture fluid flow from Darcy's law. This study contributes to the fundamental understanding of non-Darcy's flow occurrence in rock joints at the micro scale.展开更多
Cancer cells differ from normal cells in various parameters, and these differences are caused by genomic mutations and consequential altered gene expression. The genetic and functional heterogeneity of tumor cells is ...Cancer cells differ from normal cells in various parameters, and these differences are caused by genomic mutations and consequential altered gene expression. The genetic and functional heterogeneity of tumor cells is a major challenge in cancer research, detection, and effective treatment. As such, the use of diagnostic methods is important to reveal this heterogeneity at the single-cell level. Droplet microfluidic devices are effective tools that provide exceptional sensitivity for analyzing single cells and molecules. In this review, we highlight two novel methods that employ droplet microfluidics for ultrasensitive detection of nucleic acids and protein markers in cancer cells. We also discuss the future practical applications of these methods.展开更多
Static dielectric constant is a key parameter to estimate the electro-viscous effect which plays important roles in the flow and convective heat transfer of fluids with ions in microfluidic devices such as micro react...Static dielectric constant is a key parameter to estimate the electro-viscous effect which plays important roles in the flow and convective heat transfer of fluids with ions in microfluidic devices such as micro reactors and heat exchangers.A group contribution method based on 27 groups is developed for the correlation of static dielectric constant of ionic liquids in this paper.The ionic liquids considered include imidazolium,pyridinium,pyrrolidinium,alkylammonium,alkylsulfonium,morpholinium and piperidinium cations and various anions.The data collected cover the temperature ranges of 278.15-343.15 K and static dielectric constant ranges of 9.4-85.6.The results of the method show a satisfactory agreement with the literature data with an average absolute relative deviation of 7.41%,which is generally of the same order of the experimental data accuracy.The method proposed in this paper provides a simple but reliable approach for the prediction of static dielectric constant of ionic liquids at different temperatures.展开更多
Angiogenesis is very important for many physiological and pathological processes. However, the molecular mechanisms of angiogenesis are unclear. To elucidate the molecular mechanisms of angiogenesis and to develop tre...Angiogenesis is very important for many physiological and pathological processes. However, the molecular mechanisms of angiogenesis are unclear. To elucidate the molecular mechanisms of angiogenesis and to develop treatments for "angiogenesis-dependent" diseases, it is essential to establish a suitable in vitro angiogenesis model. In this study, we created a novel in vitro angiogenesis model based on a microfluidic device. Our model provides an in vivo-like microenvironment for endothelial cells (ECs) cultures and monitors the response of ECs to changes in their microenvironment in real time. To evaluate the potential of this microfluidic device for researching angiogenesis, the effects of pro-angiogenic factors on ECs proliferation, migration and tube-like structure formation were investigated. Our results showed the proliferation rate of ECs in 3D matrix was significantly promoted by the pro-angiogenic factors (with an increase of 59.12%). With the stimulation of pro-angiogenic factors gradients, ECs directionally migrated into the Matrigel from low concentrations to high concentrations and consequently formed multi-cell chords and tube-like structures. These results suggest that the device can provide a suitable platform for elucidating the mechanisms of angiogenesis and for screening pro-angiogenic or anti-angiogenic drugs for "angiogenesis-dependent" diseases.展开更多
文摘快速、灵敏和特异性地检测病原微生物,在临床诊断和传染病控制中具有重要意义。早期准确检测是快速控制疫区疫情的有效措施,尤其是在缺乏有效治疗和疫苗的情况下。聚合酶链式反应(PCR)作为常用的核酸检测技术和疾病诊断的“金标准”,有着高灵敏度的优势,但同时也存在以牺牲特异性为代价的现象。酶联免疫吸附试验(ELISA)是一种快速、特异性强的蛋白质和小分子诊断工具。然而,灵敏度低和样品预处理复杂的操作步骤极大地限制了该方法现场检测的应用。因此,快速、灵敏和特异性的检测技术成为了急需解决的要点,随着技术的应用和发展,基于CRISPR-Cas的生物传感系统的优异性能在开发病原微生物诊断技术方面引起了人们的关注。本文综述了CRISPR/Cas系统在病原微生物检测的作用机制及原理,总结了新型检测技术的优缺点并对应用发展前景进行展望。Rapid, sensitive, and specific detection of pathogenic microorganisms is crucial for clinical diagnosis and infectious disease control. Early and accurate detection is an effective measure to quickly control epidemic outbreaks, especially in the absence of effective treatments and vaccines. Polymerase Chain Reaction (PCR) is a commonly used nucleic acid testing technology and the “gold standard” for disease diagnosis with high sensitivity. However, it often sacrifices specificity. Enzyme-Linked Immunosorbent Assay (ELISA) is a rapid and highly specific diagnostic tool for proteins and small molecules. Nevertheless, its low sensitivity and complex sample preprocessing steps greatly limit its application in on-site testing. Therefore, the development of rapid, sensitive, and specific detection technologies has become an urgent need. With the application and advancement of technology, the excellent performance of CRISPR-Cas based biosensing systems has attracted attention in the development of pathogenic microorganism diagnostic techniques. This article reviews the mechanisms and principles of CRISPR/Cas systems in pathogenic microorganism detection, summarizes the advantages and disadvantages of novel detection technologies, and provides an outlook on their future applications.
基金supported by the National Basic Research Program of China(No.2011CB911104)
文摘In this paper, we present a novel design scheme of temperature-jump(T-jump) area for microfluidic device.Numerical simulation and experimental research of thermal characteristics of the solution in microchannels is completed.Numerical simulation of the temperature-jump microchannel is analyzed to study the heat transfer characteristics by comparing performance of three proposed configurations.Calculation of the power requirement is discussed in the dimensional design of microheater. Temperature-sensitive fluorescent dye is applied to investigate the temperature field of microchannel heated by a designed microheater. It is found that the T-jump microfluidic device can provide rapid heating for solutions with strong convection heat transfer ability.
基金Supported by the National Natural Science Foundation of China (20525622,20876084)the National Basic Research Program of China (2007CB714302)
文摘This paper presents the experimental results of liquid-liquid microflows in a coaxial microfluidic device with mass transfer.Three working systems were n-butanol + phosphoric acid(PA) + water,methyl isobutyl ketone(MIBK) + PA + water,30% kerosene in tri-n-butylphosphate(TBP) + PA + water.The direction and intensity of mass transfer were adjusted by adding PA in one of two phases mutual saturated in advance.When PA transferred from the organic phase to the aqueous phase,tiny aqueous droplets may generate inside the organic phase by mass transfer inducement to form a new W/O/W flow pattern directly on some special cases.Once the PA concentration was very high,violent Marangoni effect could be observed to throw part of organic phase out of droplets as tail.The interphase transfer of PA could expand the jetting flow region,in particular for systems with low or medium inter-facial tension and when the mass transfer direction was from the aqueous phase to the organic phase.
基金support from the Australian Research Council-linkage Project
文摘Advanced microfluidic technology was used to examine the microscopic viscous and inertial effects evolution of water flow in rock joints. The influence of void space on fluid flow behaviour in rock joints under different flow velocities was experimentally investigated at the micro scale. Using advanced fabrication technology of microfluidic device, micro flow channels of semicircular, triangular, rectangular and pentagonal cavities were fabricated to simulate different void space of rock joints, respectively. Using the fluorescence labelling approach, the trajectory of water flow was captured by the microscope digital camera when it passed over the cavity under different flow velocities. The flow tests show that the flow trajectory deviated towards the inside of the cavity at low flow velocities. With the increase in flow velocity, this degree of flow trajectory deviation decreased until there was no trajectory deviation for flow in the straight parallel channel. The flow trajectory deviation initially reduced from the void corner near the entrance. At the same time, a small eddy appeared near the void corner of the entrance. The size and intensity of the eddy increased with the flow velocity until it occupied the whole cavity domain. The gradual reduction of flow trajectory near the straight parallel channel and the growth of eddy inside the cavity reflect the evolution of microscopic viscous and inertial forces under different flow velocities.The eddy formed inside the cavity does not contribute to the total flow flux, but the running of the eddy consumes flow energy. This amount of pressure loss due to voids could contribute to the nonlinear deviation of fracture fluid flow from Darcy's law. This study contributes to the fundamental understanding of non-Darcy's flow occurrence in rock joints at the micro scale.
基金supported by a grant from the National Institutes of Health (Grant No. NIH/NGRR 1R21RR025371–01 to IS)
文摘Cancer cells differ from normal cells in various parameters, and these differences are caused by genomic mutations and consequential altered gene expression. The genetic and functional heterogeneity of tumor cells is a major challenge in cancer research, detection, and effective treatment. As such, the use of diagnostic methods is important to reveal this heterogeneity at the single-cell level. Droplet microfluidic devices are effective tools that provide exceptional sensitivity for analyzing single cells and molecules. In this review, we highlight two novel methods that employ droplet microfluidics for ultrasensitive detection of nucleic acids and protein markers in cancer cells. We also discuss the future practical applications of these methods.
基金Supported by the National Natural Science Foundation of China(21176206)the Project of Zhejiang Key Scientific and Technological Innovation Team(2010R50017)
文摘Static dielectric constant is a key parameter to estimate the electro-viscous effect which plays important roles in the flow and convective heat transfer of fluids with ions in microfluidic devices such as micro reactors and heat exchangers.A group contribution method based on 27 groups is developed for the correlation of static dielectric constant of ionic liquids in this paper.The ionic liquids considered include imidazolium,pyridinium,pyrrolidinium,alkylammonium,alkylsulfonium,morpholinium and piperidinium cations and various anions.The data collected cover the temperature ranges of 278.15-343.15 K and static dielectric constant ranges of 9.4-85.6.The results of the method show a satisfactory agreement with the literature data with an average absolute relative deviation of 7.41%,which is generally of the same order of the experimental data accuracy.The method proposed in this paper provides a simple but reliable approach for the prediction of static dielectric constant of ionic liquids at different temperatures.
基金supported by the National Natural Science Foundation of China (10872224, 81000067, 30870607)the Fundamental Research Funds for the Central Universities (CDJXS10 23 11 15)+1 种基金CQNS grant (CSTC2008BB5192)Visiting Scholar Foundation of Key Laboratory of Biorheological Science and Technology (Chongqing University) of Ministry of Education
文摘Angiogenesis is very important for many physiological and pathological processes. However, the molecular mechanisms of angiogenesis are unclear. To elucidate the molecular mechanisms of angiogenesis and to develop treatments for "angiogenesis-dependent" diseases, it is essential to establish a suitable in vitro angiogenesis model. In this study, we created a novel in vitro angiogenesis model based on a microfluidic device. Our model provides an in vivo-like microenvironment for endothelial cells (ECs) cultures and monitors the response of ECs to changes in their microenvironment in real time. To evaluate the potential of this microfluidic device for researching angiogenesis, the effects of pro-angiogenic factors on ECs proliferation, migration and tube-like structure formation were investigated. Our results showed the proliferation rate of ECs in 3D matrix was significantly promoted by the pro-angiogenic factors (with an increase of 59.12%). With the stimulation of pro-angiogenic factors gradients, ECs directionally migrated into the Matrigel from low concentrations to high concentrations and consequently formed multi-cell chords and tube-like structures. These results suggest that the device can provide a suitable platform for elucidating the mechanisms of angiogenesis and for screening pro-angiogenic or anti-angiogenic drugs for "angiogenesis-dependent" diseases.
