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Sample records for genetic detection microfluidic

  1. Rapid detection of genetically modified organisms on a continuous-flow polymerase chain reaction microfluidics.

    Science.gov (United States)

    Li, Yuyuan; Xing, Da; Zhang, Chunsun

    2009-02-01

    The ability to perform DNA amplification on a microfluidic device is very appealing. In this study, a compact continuous-flow polymerase chain reaction (PCR) microfluidics was developed for rapid analysis of genetically modified organisms (GMOs) in genetically modified soybeans. The device consists of three pieces of copper and a transparent polytetrafluoroethylene capillary tube embedded in the spiral channel fabricated on the copper. On this device, the P35S and Tnos sequences were successfully amplified within 9min, and the limit of detection of the DNA sample was estimated to be 0.005 ng microl(-1). Furthermore, a duplex continuous-flow PCR was also reported for the detection of the P35S and Tnos sequences in GMOs simultaneously. This method was coupled with the intercalating dye SYBR Green I and the melting curve analysis of the amplified products. Using this method, temperature differences were identified by the specific melting temperature values of two sequences, and the limit of detection of the DNA sample was assessed to be 0.01 ng microl(-1). Therefore, our results demonstrated that the continuous-flow PCR assay could discriminate the GMOs in a cost-saving and less time-consuming way.

  2. Enzyme detection by microfluidics

    DEFF Research Database (Denmark)

    2013-01-01

    Microfluidic-implemented methods of detecting an enzyme, in particular a DNA-modifying enzyme, are provided, as well as methods for detecting a cell, or a microorganism expressing said enzyme. The enzyme is detected by providing a nucleic acid substrate, which is specifically targeted...

  3. Enzyme detection by microfluidics

    DEFF Research Database (Denmark)

    2013-01-01

    Microfluidic-implemented methods of detecting an enzyme, in particular a DNA-modifying enzyme, are provided, as well as methods for detecting a cell, or a microorganism expressing said enzyme. The enzyme is detected by providing a nucleic acid substrate, which is specifically targeted...... by that enzyme...

  4. Quantum dots and microfluidic single-molecule detection for screening genetic and epigenetic cancer markers in clinical samples

    Science.gov (United States)

    Wang, Tza-Huei; Bailey, Vasudev; Liu, Kelvin

    2011-06-01

    Genomic analysis of biomarkers, including genetic markers such as point mutations and epigenetic markers such as DNA methylation, has become a central theme in modern disease diagnosis and prognosis. Recently there is an increasing interest in using single-molecule detection (SMD) for genomic detection. The driving force not only comes from its ultrahigh sensitivity that can allow the detection of low-abundance nucleic acids with reduced or without the need of amplification but also from its potential in achieving high-accuracy quantification of rare targets via singlemolecule sorting. The unique photophysical properties of semiconductor quantum dots (QDs) have made them ideal for use as spectral labels and luminescent probes. QDs also make excellent donors to pair with organic dyes in the fluorescence resonance energy transfer (FRET) process due to the features of narrow emission spectra and small Stokes shift. We have developed highly sensitive, quantitative and clinically relevant technologies for analysis of genomic markers based on the convergence of SMD, microfluidic manipulations, and quantum dot fluorescence resonance energy transfer technology (QD-FRET). Extraordinary performances of these new technologies have been exemplified by analysis of a variety of biomarkers including point mutations, DNA integrity and DNA methylation in clinical samples.

  5. Optical detection in microfluidic systems

    DEFF Research Database (Denmark)

    Mogensen, Klaus Bo; Kutter, Jörg Peter

    2009-01-01

    Optical detection schemes continue to be favoured for measurements in microfluidic systems. A selection of the latest progress mainly within the last two years is critically reviewed. Emphasis is on integrated solutions, such as planar waveguides, coupling schemes to the outside world, evanescent...... to ease commercialisation of the devices. This work will hopefully result in more commercial products that benefit from integrated optics, because the impact on commercial devices so far has been modest....

  6. A microfluidic based optical particle detection method

    Science.gov (United States)

    Dou, James; Chen, Lu; Nayyar, Rakesh; Aitchison, Stewart

    2012-03-01

    An optical particle detection and analysis method is presented. This method combines the capillary microfluidics, integrated optics and novel image acquisition and analysis algorithms to form the basis of a portable or handheld cytometer instrument. Experimental results provided shows the testing results are closely matched with conventional flow cytometer data.

  7. Microfluidic distillation chip for methanol concentration detection.

    Science.gov (United States)

    Wang, Yao-Nan; Liu, Chan-Chiung; Yang, Ruey-Jen; Ju, Wei-Jhong; Fu, Lung-Ming

    2016-03-17

    An integrated microfluidic distillation system is proposed for separating a mixed ethanol-methanol-water solution into its constituent components. The microfluidic chip is fabricated using a CO2 laser system and comprises a serpentine channel, a boiling zone, a heating zone, and a cooled collection chamber filled with de-ionized (DI) water. In the proposed device, the ethanol-methanol-water solution is injected into the microfluidic chip and driven through the serpentine channel and into the collection chamber by means of a nitrogen carrier gas. Following the distillation process, the ethanol-methanol vapor flows into the collection chamber and condenses into the DI water. The resulting solution is removed from the collection tank and reacted with a mixed indicator. Finally, the methanol concentration is inversely derived from the absorbance measurements obtained using a spectrophotometer. The experimental results show the proposed microfluidic system achieves an average methanol distillation efficiency of 97%. The practicality of the proposed device is demonstrated by detecting the methanol concentrations of two commercial fruit wines. It is shown that the measured concentration values deviate by no more than 3% from those obtained using a conventional bench top system.

  8. Fish-on-a-chip: a sensitive detection microfluidic system for alzheimer's disease

    Directory of Open Access Journals (Sweden)

    An Jeongho

    2011-05-01

    Full Text Available Abstract Microfluidics has become an important tool in diagnosing many diseases, including neurological and genetic disorders. Alzheimer's disease (AD is a neurodegenerative disease that irreversibly and progressively destroys memory, language ability, and thinking skills. Commonly, detection of AD is expensive and complex. Fluorescence in situ hybridization (FISH-based microfluidic chip platform is capable of diagnosing AD at an early stage and they are effective tools for the diagnosis with low cost, high speed, and high sensitivity. In this review, we tried to provide basic information on the diagnosis of AD via FISH-based microfluidics. Different sample preparations using a microfluidic chip for diagnosis of AD are highlighted. Moreover, rapid innovations in nanotechnology for diagnosis are explained. This review will provide information on dynamic quantification methods for the diagnosis and treatment of AD. The knowledge provided in this review will help develop new integration diagnostic techniques based on FISH and microfluidics.

  9. Detection methods for centrifugal microfluidic platforms

    DEFF Research Database (Denmark)

    Burger, Robert; Amato, Letizia; Boisen, Anja

    2016-01-01

    Centrifugal microfluidics has attracted much interest from academia as well as industry, since it potentially offers solutions for affordable, user-friendly and portable biosensing. A wide range of so-called fluidic unit operations, e.g. mixing, metering, liquid routing, and particle separation......, have been developed and allow automation and integration of complex assay protocols in lab-on-a-disc systems. Besides liquid handling, the detection strategy for reading out the assay is crucial for developing a fully integrated system. In this review, we focus on biosensors and readout methods...

  10. Fabrication of Microfluidic Fiber Chip Detection System

    Institute of Scientific and Technical Information of China (English)

    Bo Su; Da-fu Cui; Chang-chun Liu; Xing Chen

    2006-01-01

    The diameter of the excitation beam was decreased greatly by integrating the fiber on the microfluidic chip as light propagation medium. The coupling efficiency of the fiber was improved with optical fiber collimation device coupling beam.The chip was placed in the darkroom to avoid the interference of the external light. The cost of the instrument was decreased with a high brightness blue LED as excitation source; the performance of the system was valuated by the determination of FITC fluorescein with a minimum detectable concentration of 2.2×10-8 mol/L, the Signal-to-Noise Ratio (SNR) S/N=5. The correlation coefficient of the detection system within the range of 1.8 × 10-7 mol/L~ 4 × 10-5mol/L was 0.9972.

  11. Microfluidic immunomagnetic separation for enhanced bacterial detection

    DEFF Research Database (Denmark)

    Hoyland, James; Kunstmann-Olsen, Casper; Ahmed, Shakil

    A combined lab-on-a-chip approach combining immunomagnetic separation (IMS) and flow cytometry was developed for the enrichment and detection of salmonella contamination in food samples. Immunomagnetic beads were immobilized in chips consisting of long fractal meanders while contaminated samples...... to obtain maximum capturing efficiency. The effects of channel volume, path length and number of bends of microfluidic chip on IMS efficiency were also determined....... were flowed over them. After incubation the beads can be released for detection into the flow-cytometry chip. Immunomagnetic beads were prepared by using anti-Salmonella antibodies and magnetic beads (2.8μm). Both the synthesized and commercially available anti-Salmonella beads were used to capture...

  12. Microfluidic CODES: a scalable multiplexed electronic sensor for orthogonal detection of particles in microfluidic channels.

    Science.gov (United States)

    Liu, Ruxiu; Wang, Ningquan; Kamili, Farhan; Sarioglu, A Fatih

    2016-04-21

    Numerous biophysical and biochemical assays rely on spatial manipulation of particles/cells as they are processed on lab-on-a-chip devices. Analysis of spatially distributed particles on these devices typically requires microscopy negating the cost and size advantages of microfluidic assays. In this paper, we introduce a scalable electronic sensor technology, called microfluidic CODES, that utilizes resistive pulse sensing to orthogonally detect particles in multiple microfluidic channels from a single electrical output. Combining the techniques from telecommunications and microfluidics, we route three coplanar electrodes on a glass substrate to create multiple Coulter counters producing distinct orthogonal digital codes when they detect particles. We specifically design a digital code set using the mathematical principles of Code Division Multiple Access (CDMA) telecommunication networks and can decode signals from different microfluidic channels with >90% accuracy through computation even if these signals overlap. As a proof of principle, we use this technology to detect human ovarian cancer cells in four different microfluidic channels fabricated using soft lithography. Microfluidic CODES offers a simple, all-electronic interface that is well suited to create integrated, low-cost lab-on-a-chip devices for cell- or particle-based assays in resource-limited settings.

  13. Reconfigurable microfluidic nanoparticle trapping using dielectrophoresis for chemical detection

    Science.gov (United States)

    Salemmilani, Reza; Piorek, Brian; Moskovits, Martin; Meinhart, Carl

    2016-11-01

    We report a microfluidic particle manipulation platform based on dielectrophoresis (DEP) to capture and release nanoscale particles cyclically via reconfigurable traps. DEP is routinely used in microfluidic devices for capturing and trapping cells and particles of various sizes, however the trapping of small nanoparticles by DEP is challenging due to the inverse relationship of the DEP force with particle size. The architecture we describe uses electrically insulating silica beads of micron scale in conjunction with DEP electrodes configured to manipulate nanoscale particles for microfluidic applications such as filtration and chemical detection. Department of Mechanical Engineering, University of California, Santa Barbara, California 93106, United States.

  14. Genetic interaction mapping with microfluidic-based single cell sequencing

    Science.gov (United States)

    Haliburton, John R.; Shao, Wenjun; Deutschbauer, Adam; Arkin, Adam; Abate, Adam R.

    2017-01-01

    Genetic interaction mapping is useful for understanding the molecular basis of cellular decision making, but elucidating interactions genome-wide is challenging due to the massive number of gene combinations that must be tested. Here, we demonstrate a simple approach to thoroughly map genetic interactions in bacteria using microfluidic-based single cell sequencing. Using single cell PCR in droplets, we link distinct genetic information into single DNA sequences that can be decoded by next generation sequencing. Our approach is scalable and theoretically enables the pooling of entire interaction libraries to interrogate multiple pairwise genetic interactions in a single culture. The speed, ease, and low-cost of our approach makes genetic interaction mapping viable for routine characterization, allowing the interaction network to be used as a universal read out for a variety of biology experiments, and for the elucidation of interaction networks in non-model organisms. PMID:28170417

  15. Development of a Plastic-Based Microfluidic Immunosensor Chip for Detection of H1N1 Influenza

    Directory of Open Access Journals (Sweden)

    Tae Jung Park

    2012-08-01

    Full Text Available Lab-on-a-chip can provide convenient and accurate diagnosis tools. In this paper, a plastic-based microfluidic immunosensor chip for the diagnosis of swine flu (H1N1 was developed by immobilizing hemagglutinin antigen on a gold surface using a genetically engineered polypeptide. A fluorescent dye-labeled antibody (Ab was used for quantifying the concentration of Ab in the immunosensor chip using a fluorescent technique. For increasing the detection efficiency and reducing the errors, three chambers and three microchannels were designed in one microfluidic chip. This protocol could be applied to the diagnosis of other infectious diseases in a microfluidic device.

  16. An Integrated Microfluidic Chip for Rapid Methanol Detection

    Directory of Open Access Journals (Sweden)

    Ting-Fu Hong

    2012-03-01

    Full Text Available A widely-available CO2 laser scriber is used to perform direct-writing ablation on a poly(methyl methacrylate (PMMA substrate to create a microfluidic chip for the rapid detection of methanol. The microfluidic designs are created using commercial layout software and are converted into the command signals required to drive the laser scriber in such a way as to reproduce the desired microchannel configuration on the surface of a PMMA substrate. Experimental results indicate that, using the proposed integrated microfluidic chip, linearity expression R2 can reach 0.9972 when using 2 unit methanol oxidase (MOX and basic fuchsin to detect methanol. The proposed device is thus a valuable tool for rapid methanol detection, with its micro mixer system providing a simple yet effective solution for mixing problems in the field of micro-total-analysis-systems.

  17. Centrifugal microfluidic platform for ultrasensitive detection of botulinum toxin.

    Science.gov (United States)

    Koh, Chung-Yan; Schaff, Ulrich Y; Piccini, Matthew E; Stanker, Larry H; Cheng, Luisa W; Ravichandran, Easwaran; Singh, Bal-Ram; Sommer, Greg J; Singh, Anup K

    2015-01-20

    We present an innovative centrifugal microfluidic immunoassay platform (SpinDx) to address the urgent biodefense and public health need for ultrasensitive point-of-care/incident detection of botulinum toxin. The simple, sample-to-answer centrifugal microfluidic immunoassay approach is based on binding of toxins to antibody-laden capture particles followed by sedimentation of the particles through a density-media in a microfluidic disk and quantification by laser-induced fluorescence. A blind, head-to-head comparison study of SpinDx versus the gold-standard mouse bioassay demonstrates 100-fold improvement in sensitivity (limit of detection = 0.09 pg/mL), while achieving total sample-to-answer time of capture beads and detection antibodies) are disconnected from the disk architecture and the reader, facilitating rapid development of new assays. SpinDx can also serve as a general-purpose immunoassay platform applicable to diagnosis of other conditions and diseases.

  18. Centrifugally driven microfluidic disc for detection of chromosomal translocations

    DEFF Research Database (Denmark)

    Brøgger, Anna Line; Kwasny, Dorota; Bosco, Filippo G.

    2012-01-01

    and prognosis of patients. In this work we demonstrate a novel, centrifugally-driven microfluidic system for controlled manipulation of oligonucleotides and subsequent detection of chromosomal translocations. The device is fabricated in the form of a disc with capillary burst microvalves employed to control...

  19. Scintillation particle detection based on microfluidics

    CERN Document Server

    Mapelli, A; Renaud, P; Gorini, B; Trivino, N Vico; Jiguet, S; Vandelli, W; Haguenauer, M

    2010-01-01

    A novel type of particle detector based on scintillation, with precise spatial resolution and high radiation hardness, is being studied. It consists of a single microfluidic channel filled with a liquid scintillator and is designed to define an array of scintillating waveguides each independently coupled to a photodetector. Prototype detectors built using an SU-8 epoxy resin have been tested with electrons from a radioactive source. The experimental results show a light yield compatible with the theoretical expectations and confirm the validity of the approach. (C) 2010 Elsevier B.V. All rights reserved.

  20. Microfluidic biosensor for cholera toxin detection in fecal samples.

    Science.gov (United States)

    Bunyakul, Natinan; Promptmas, Chamras; Baeumner, Antje J

    2015-01-01

    Sample preparation and processing steps are the most critical assay aspects that require our attention in the development of diagnostic devices for analytes present in complex matrices. In the best scenarios, diagnostic devices should use only simple sample processing. We have therefore investigated minimal preparation of stool samples and their effect on our sensitive microfluidic immunosensor for the detection of cholera toxin. This biosensor was previously developed and tested in buffer solutions only, using either fluorescence or electrochemical detection strategies. The microfluidic devices were made from polydimethylsiloxane using soft lithography and silicon templates. Cholera toxin subunit B (CTB)-specific antibodies immobilized onto superparamagnetic beads and ganglioside GM1-containing liposomes were used for CTB recognition in the detection system. Quantification of CTB was tested by spiking it in human stool samples. Here, optimal minimal sample processing steps, including filtration and centrifugation, were optimized using a microtiter plate assay owing to its high-throughput capabilities. Subsequently, it was transferred to the microfluidic systems, enhancing the diagnostic characteristic of the biosensor. It was found that the debris removal obtained through simple centrifugation resulted in an acceptable removal of matrix effects for the fluorescence format, reaching a limit of detection of only 9.0 ng/mL. However, the electron transfer in the electrochemical format was slightly negatively affected (limit of detection of 31.7 ng/mL). Subsequently, cross-reactivity using the heat-labile Escherichia coli toxin was investigated using the electrochemical microfluidic immunosensors and was determined to be negligible. With minimal sample preparation required, these microfluidic liposome-based systems have demonstrated excellent analytical performance in a complex matrix and will thus be applicable to other sample matrices.

  1. A Microfluidics-HPLC/Differential Mobility Spectrometer Macromolecular Detection System for Human and Robotic Missions

    Science.gov (United States)

    Coy, S. L.; Killeen, K.; Han, J.; Eiceman, G. A.; Kanik, I.; Kidd, R. D.

    2011-01-01

    Our goal is to develop a unique, miniaturized, solute analyzer based on microfluidics technology. The analyzer consists of an integrated microfluidics High Performance Liquid Chromatographic chip / Differential Mobility Spectrometer (?HPLCchip/ DMS) detection system

  2. A Microfluidics-HPLC/Differential Mobility Spectrometer Macromolecular Detection System for Human and Robotic Missions

    Science.gov (United States)

    Coy, S. L.; Killeen, K.; Han, J.; Eiceman, G. A.; Kanik, I.; Kidd, R. D.

    2011-01-01

    Our goal is to develop a unique, miniaturized, solute analyzer based on microfluidics technology. The analyzer consists of an integrated microfluidics High Performance Liquid Chromatographic chip / Differential Mobility Spectrometer (?HPLCchip/ DMS) detection system

  3. Detection of heavy metal by paper-based microfluidics.

    Science.gov (United States)

    Lin, Yang; Gritsenko, Dmitry; Feng, Shaolong; Teh, Yi Chen; Lu, Xiaonan; Xu, Jie

    2016-09-15

    Heavy metal pollution has shown great threat to the environment and public health worldwide. Current methods for the detection of heavy metals require expensive instrumentation and laborious operation, which can only be accomplished in centralized laboratories. Various microfluidic paper-based analytical devices have been developed recently as simple, cheap and disposable alternatives to conventional ones for on-site detection of heavy metals. In this review, we first summarize current development of paper-based analytical devices and discuss the selection of paper substrates, methods of device fabrication, and relevant theories in these devices. We then compare and categorize recent reports on detection of heavy metals using paper-based microfluidic devices on the basis of various detection mechanisms, such as colorimetric, fluorescent, and electrochemical methods. To finalize, the future development and trend in this field are discussed. Copyright © 2016 Elsevier B.V. All rights reserved.

  4. Confocal epifluorescence detection for microspheres delivered on disposable microfluidic chip

    Institute of Scientific and Technical Information of China (English)

    Honghua Hu; Xiyun Hou; Guoguang Yang

    2006-01-01

    @@ The laser induced fluorescence (LIF) detection system for 5-μm microspheres delivered on microfluidic chip is presented employing confocal optical scheme. The parameters of the optical system are specifically optimized for single microsphere detection. With the excitation laser spot size of 4.6 μm and optical sectioning power of 27 μm, the lowest concentration detection limit is 0.45 nmol/L, corresponding to only 122 molecules in probe volume. The microsphere detection is carried on successfully with the maximum signal-to-noise ratio (SNR) of 55.7, which provides good detection sensitivity.

  5. Performance of an integrated microoptical system for fluorescence detection in microfluidic systems

    NARCIS (Netherlands)

    Roulet, Jean-Christophe; Völkel, Reinhard; Herzig, Hans Peter; Verpoorte, Elisabeth; De Rooij, Nico F.; Dändliker, René

    2002-01-01

    This article presents a new integrated microfluidic/microoptic device designed for basic biochemical analysis. The microfluidic network is Wet-etched in a Borofloat 33 (Pyrex) glass wafer and sealed by means of a second wafer. Unlike other similar microfluidic systems, elements of the detection syst

  6. Analytical detection techniques for droplet microfluidics--a review.

    Science.gov (United States)

    Zhu, Ying; Fang, Qun

    2013-07-17

    In the last decade, droplet-based microfluidics has undergone rapid progress in the fields of single-cell analysis, digital PCR, protein crystallization and high throughput screening. It has been proved to be a promising platform for performing chemical and biological experiments with ultra-small volumes (picoliter to nanoliter) and ultra-high throughput. The ability to analyze the content in droplet qualitatively and quantitatively is playing an increasing role in the development and application of droplet-based microfluidic systems. In this review, we summarized the analytical detection techniques used in droplet systems and discussed the advantage and disadvantage of each technique through its application. The analytical techniques mentioned in this paper include bright-field microscopy, fluorescence microscopy, laser induced fluorescence, Raman spectroscopy, electrochemistry, capillary electrophoresis, mass spectrometry, nuclear magnetic resonance spectroscopy, absorption detection, chemiluminescence, and sample pretreatment techniques. The importance of analytical detection techniques in enabling new applications is highlighted. We also discuss the future development direction of analytical detection techniques for droplet-based microfluidic systems.

  7. Multi-Spectral Detection of Microfluidic Separation Products.

    Energy Technology Data Exchange (ETDEWEB)

    Hayden, Carl C.; Meagher, Robert

    2007-12-01

    The objectives of this project were to develop a new scientific tool for studies of chemical processes at the single molecule level, and to provide enhanced capabilities for multiplexed, ultrasensitive separations and immunoassays. We have combined microfluidic separation techniques with our newly developed technology for spectrally and temporally resolved detection of single molecules. The detection of individual molecules can reveal fluctuations in molecular conformations, which are obscured in ensemble measurements, and allows detailed studies of reaction kinetics such as ligand or antibody binding. Detection near the single molecule level also enables the use of correlation techniques to extract information, such as diffusion rates, from the fluorescence signal. The micro-fluidic technology offers unprecedented control of the chemical environment and flow conditions, and affords the unique opportunity to study biomolecules without immobilization. For analytical separations, the fluorescence lifetime and spectral resolution of the detection makes it possible to use multiple parameters for identification of separation products to improve the certainty of identification. We have successfully developed a system that can measure fluorescence spectra, lifetimes and diffusion constants of the components of mixtures separated in a microfluidic electrophoresis chip.

  8. Microfluidic Arrayed Lab-On-A-Chip for Electrochemical Capacitive Detection of DNA Hybridization Events.

    Science.gov (United States)

    Ben-Yoav, Hadar; Dykstra, Peter H; Bentley, William E; Ghodssi, Reza

    2017-01-01

    A microfluidic electrochemical lab-on-a-chip (LOC) device for DNA hybridization detection has been developed. The device comprises a 3 × 3 array of microelectrodes integrated with a dual layer microfluidic valved manipulation system that provides controlled and automated capabilities for high throughput analysis of microliter volume samples. The surface of the microelectrodes is functionalized with single-stranded DNA (ssDNA) probes which enable specific detection of complementary ssDNA targets. These targets are detected by a capacitive technique which measures dielectric variation at the microelectrode-electrolyte interface due to DNA hybridization events. A quantitative analysis of the hybridization events is carried out based on a sensing modeling that includes detailed analysis of energy storage and dissipation components. By calculating these components during hybridization events the device is able to demonstrate specific and dose response sensing characteristics. The developed microfluidic LOC for DNA hybridization detection offers a technology for real-time and label-free assessment of genetic markers outside of laboratory settings, such as at the point-of-care or in-field environmental monitoring.

  9. A brief review on microfluidic platforms for hormones detection.

    Science.gov (United States)

    Ozhikandathil, Jayan; Badilescu, Simona; Packirisamy, Muthukumaran

    2017-01-01

    Lab-on-chip technology is attracting great interest due to its potential as miniaturized devices that can automate and integrate many sample-handling steps, minimize consumption of reagent and samples, have short processing time and enable multiplexed analysis. Microfluidic devices have demonstrated their potential for a broad range of applications in life sciences, including point-of-care diagnostics and personalized medicine, based on the routine diagnosis of levels of hormones, cancer markers, and various metabolic products in blood, serum, etc. Microfluidics offers an adaptable platform that can facilitate cell culture as well as monitor their activity and control the cellular environment. Signaling molecules released from cells such as neurotransmitters and hormones are important in assessing the health of cells and the effect of drugs on their functions. In this review, we provide an insight into the state-of-art applications of microfluidics for monitoring of hormones released by cells. In our works, we have demonstrated efficient detection methods for bovine growth hormones using nano and microphotonics integrated microfluidics devices. The bovine growth hormone can be used as a growth promoter in dairy farming to enhance the milk and meat production. In the recent years, a few attempts have been reported on developing very sensitive, fast and low-cost methods of detection of bovine growth hormone using micro devices. This paper reviews the current state-of-art of detection and analysis of hormone using integrated optical micro and nanofluidics systems. In addition, the paper also focuses on various lab-on-a-chip technologies reported recently, and their benefits for screening growth hormones in milk.

  10. Detection and classification of ebola on microfluidic chips

    Science.gov (United States)

    Lin, Xue; Jin, Xiangyu; Fan, Yunqian; Huang, Qin; Kou, Yue; Zu, Guo; Huang, Shiguang; Liu, Xiaosheng; Huang, Guoliang

    2016-10-01

    Point-of-care testing (POCT) for an infectious diseases is the prerequisite to control of the disease and limitation of its spread. A microfluidic chip for detection and classification of four strains of Ebola virus was developed and evaluated. This assay was based on reverse transcription loop-mediated isothermal amplification (RT-LAMP) and specific primers for Ebola Zaire virus, Ebola Sudan virus, Ebola Tai Forest virus and Ebola Bundibugyo virus were designed. The sensitivity of the microfluidic chip was under 103 copies per milliliter, as determined by ten repeated tests. This assay is unique in its ability to enable diagnosis of the Ebola infections and simultaneous typing of Ebola virus on a single chip. It offers short reaction time, ease of use and high specificity. These features should enable POCT in remote area during outbreaks of Ebola virus.

  11. Distillation and detection of SO2 using a microfluidic chip.

    Science.gov (United States)

    Ju, Wei-Jhong; Fu, Lung-Ming; Yang, Ruey-Jen; Lee, Chia-Lun

    2012-02-07

    A miniaturized distillation system is presented for separating sulfurous acid (H(2)SO(3)) into sulfur dioxide (SO(2)) and water (H(2)O). The major components of the proposed system include a microfluidic distillation chip, a power control module, and a carrier gas pressure control module. The microfluidic chip is patterned using a commercial CO(2) laser and comprises a serpentine channel, a heating zone, a buffer zone, a cooling zone, and a collection tank. In the proposed device, the H(2)SO(3) solution is injected into the microfluidic chip and is separated into SO(2) and H(2)O via an appropriate control of the distillation time and temperature. The gaseous SO(2) is then transported into the collection chamber by the carrier gas and is mixed with DI water. Finally, the SO(2) concentration is deduced from the absorbance measurements obtained using a spectrophotometer. The experimental results show that a correlation coefficient of R(2) = 0.9981 and a distillation efficiency as high as 94.6% are obtained for H(2)SO(3) solutions with SO(2) concentrations in the range of 100-500 ppm. The SO(2) concentrations of two commercial red wines are successfully detected using the developed device. Overall, the results presented in this study show that the proposed system provides a compact and reliable tool for SO(2) concentration measurement purposes.

  12. A personification heuristic Genetic Algorithm for Digital Microfluidics-based Biochips Placement

    Directory of Open Access Journals (Sweden)

    Jingsong Yang

    2013-06-01

    Full Text Available A personification heuristic Genetic Algorithm is established for the placement of digital microfluidics-based biochips, in which, the personification heuristic algorithm is used to control the packing process, while the genetic algorithm is designed to be used in multi-objective placement results optimizing. As an example, the process of microfluidic module physical placement in multiplexed in-vitro diagnostics on human physiological fluids is simulated. The experiment results show that personification heuristic genetic algorithm can achieve better results in multi-objective optimization, compare to the parallel recombinative simulated annealing algorithm.

  13. Quantum dot-based microfluidic biosensor for cancer detection

    Energy Technology Data Exchange (ETDEWEB)

    Ghrera, Aditya Sharma [Biomedical Instrumentation Section, CSIR-National Physical Laboratory, New Delhi-110012 (India); School of Engineering and Technology, ITM University, Gurgaon-122017 (India); Pandey, Chandra Mouli; Ali, Md. Azahar [Biomedical Instrumentation Section, CSIR-National Physical Laboratory, New Delhi-110012 (India); Malhotra, Bansi Dhar, E-mail: bansi.malhotra@gmail.com [Department of Biotechnology, Delhi Technological University, Delhi-110042 (India)

    2015-05-11

    We report results of the studies relating to fabrication of an impedimetric microfluidic–based nucleic acid sensor for quantification of DNA sequences specific to chronic myelogenous leukemia (CML). The sensor chip is prepared by patterning an indium–tin–oxide (ITO) coated glass substrate via wet chemical etching method followed by sealing with polydimethylsiloxane (PDMS) microchannel for fluid control. The fabricated microfluidic chip comprising of a patterned ITO substrate is modified by depositing cadmium selenide quantum dots (QCdSe) via Langmuir–Blodgett technique. Further, the QCdSe surface has been functionalized with specific DNA probe for CML detection. The probe DNA functionalized QCdSe integrated miniaturized system has been used to monitor target complementary DNA concentration by measuring the interfacial charge transfer resistance via hybridization. The presence of complementary DNA in buffer solution significantly results in decreased electro-conductivity of the interface due to presence of a charge barrier for transport of the redox probe ions. The microfluidic DNA biosensor exhibits improved linearity in the concentration range of 10{sup −15} M to 10{sup −11} M.

  14. Automatic particle detection and sorting in an electrokinetic microfluidic chip.

    Science.gov (United States)

    Song, Yongxin; Peng, Ran; Wang, Junsheng; Pan, Xinxiang; Sun, Yeqing; Li, Dongqing

    2013-03-01

    This paper reports a lab-on-a-chip device that can automatically detect and sort particles based on their size differences with a high resolution. The PDMS-glass microfluidic chip is made by soft-lithography technique. A differential resistive pulse sensor is employed to electrically detect the sizes of the particles in EOF generated by applying DC voltages across channels. The detected resistive pulse sensor signals, whose amplitudes are proportional to particles' sizes, will automatically trigger the sorting process that is controlled by applying a voltage pulse (36 V) whenever a target particle is detected. This method was applied to automatically detect and sort polystyrene particles and microalgae in aqueous solutions. Sorting 5 μm polymer particle from a mixture of 4- and 5-μm polystyrene particles in aqueous solution, i.e. 1 μm sorting resolution, was demonstrated. The device described in this paper is simple, automatic, and label-free with high sorting resolution. It has wide applications in sample pretreatment and target particles detection. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Ligation-based mutation detection and RCA in surface un-modified OSTE+ polymer microfluidic chambers

    DEFF Research Database (Denmark)

    Saharil, Farizah; Ahlford, Annika; Kuhnemund, Malte

    2013-01-01

    For the first time, we demonstrate DNA mutation detection in surface un-modified polymeric microfluidic chambers without suffering from bubble trapping or bubble formation. Microfluidic devices were manufactured in off-stoichiometry thiol-ene epoxy (OSTE+) polymer using an uncomplicated and rapid...

  16. The electrochemical detection of droplets in microfluidic devices.

    Science.gov (United States)

    Liu, Shujuan; Gu, Yunfeng; Le Roux, Rudolph B; Matthews, Sinéad M; Bratton, Daniel; Yunus, Kamran; Fisher, Adrian C; Huck, Wilhelm T S

    2008-11-01

    This paper presents a new electrochemical method for the detection and characterisation of aqueous droplets in an organic carrier fluid (1,2-dichloroethane) formed in flow-focusing microfluidic devices. The devices consist of a conventional flow-focusing channel 250 microm wide and 250 microm deep cast out of poly(dimethylsiloxane) (PDMS) which is sealed onto a glass substrate containing a set of microelectrodes 100 microm long. Chronoamperometric analysis of a suitable electrolyte contained in the organic phase is presented for characterising the droplet frequency and size. This chronoamperometric method is then extended to a dual working electrode approach in order to determine the velocity of the droplet. Good agreement between experimental measurements and theory was observed.

  17. Salmonella detection in a microfluidic channel using orbiting magnetic beads

    Science.gov (United States)

    Ballard, Matt; Mills, Zachary; Owen, Drew; Hanasoge, Srinivas; Hesketh, Peter; Alexeev, Alexander

    2015-03-01

    We use three-dimensional simulations to model the detection of salmonella in a complex fluid sample in a microfluidic channel. Salmonella is captured using magnetic microbeads orbiting around soft ferromagnetic discs at the microchannel bottom subjected to a rotating external magnetic field. Numerical simulations are used to model the dynamics of salmonella and microbeads throughout the detection process. We examine the effect of the channel geometry on the salmonella capture, and the forces applied to the salmonella as it is dragged through the fluid after capture. Our findings guide the design of a lab-on-a-chip device to be used for detection of salmonella in food samples in a way that ensures that salmonella captured by orbiting microbeads are preserved until they can be extracted from the system for testing, and are not washed away by the fluid flow or damaged due to the experience of excessive stresses. Such a device is needed to detect bacteria at the food source and prevention of consumption of contaminated food, and also can be used for the detection of a variety of biomaterials of interest from complex fluid samples. Support from USDA and NSF is gratefully acknowledged.

  18. A Droplet Microfluidic Platform for Automating Genetic Engineering.

    Science.gov (United States)

    Gach, Philip C; Shih, Steve C C; Sustarich, Jess; Keasling, Jay D; Hillson, Nathan J; Adams, Paul D; Singh, Anup K

    2016-05-20

    We present a water-in-oil droplet microfluidic platform for transformation, culture and expression of recombinant proteins in multiple host organisms including bacteria, yeast and fungi. The platform consists of a hybrid digital microfluidic/channel-based droplet chip with integrated temperature control to allow complete automation and integration of plasmid addition, heat-shock transformation, addition of selection medium, culture, and protein expression. The microfluidic format permitted significant reduction in consumption (100-fold) of expensive reagents such as DNA and enzymes compared to the benchtop method. The chip contains a channel to continuously replenish oil to the culture chamber to provide a fresh supply of oxygen to the cells for long-term (∼5 days) cell culture. The flow channel also replenished oil lost to evaporation and increased the number of droplets that could be processed and cultured. The platform was validated by transforming several plasmids into Escherichia coli including plasmids containing genes for fluorescent proteins GFP, BFP and RFP; plasmids with selectable markers for ampicillin or kanamycin resistance; and a Golden Gate DNA assembly reaction. We also demonstrate the applicability of this platform for transformation in widely used eukaryotic organisms such as Saccharomyces cerevisiae and Aspergillus niger. Duration and temperatures of the microfluidic heat-shock procedures were optimized to yield transformation efficiencies comparable to those obtained by benchtop methods with a throughput up to 6 droplets/min. The proposed platform offers potential for automation of molecular biology experiments significantly reducing cost, time and variability while improving throughput.

  19. Rapid detection of hemagglutination using restrictive microfluidic channels equipped with waveguide-mode sensors

    Science.gov (United States)

    Ashiba, Hiroki; Fujimaki, Makoto; Awazu, Koichi; Fu, Mengying; Ohki, Yoshimichi; Tanaka, Torahiko; Makishima, Makoto

    2016-02-01

    Hemagglutination is utilized for various immunological assays, including blood typing and virus detection. Herein, we describe a method of rapid hemagglutination detection based on a microfluidic channel installed on an optical waveguide-mode sensor. Human blood samples mixed with hemagglutinating antibodies associated with different blood groups were injected into the microfluidic channel, and reflectance spectra of the samples were measured after stopping the flow. The agglutinated and nonagglutinated samples were distinguishable by the alterations in their reflectance spectra with time; the microfluidic channels worked as spatial restraints for agglutinated red blood cells. The demonstrated system allowed rapid hemagglutination detection within 1 min. The suitable height of the channels was also discussed.

  20. Electrochemical microfluidic biosensor for the detection of nucleic acid sequences.

    Science.gov (United States)

    Goral, Vasiliy N; Zaytseva, Natalya V; Baeumner, Antje J

    2006-03-01

    A microfluidic biosensor with electrochemical detection for the quantification of nucleic acid sequences was developed. In contrast to most microbiosensors that are based on fluorescence for signal generation, it takes advantage of the simplicity and high sensitivity provided by an amperometric and coulorimetric detection system. An interdigitated ultramicroelectrode array (IDUA) was fabricated in a glass chip and integrated directly with microchannels made of poly(dimethylsiloxane) (PDMS). The assembly was packaged into a Plexiglas housing providing fluid and electrical connections. IDUAs were characterized amperometrically and using cyclic voltammetry with respect to static and dynamic responses for the presence of a reversible redox couple-potassium hexacyanoferrate (ii)/hexacyanoferrate (iii) (ferri/ferrocyanide). A combined concentration of 0.5 microM of ferro/ferricyanide was determined as lower limit of detection with a dynamic range of 5 orders of magnitude. Background signals were negligible and the IDUA responded in a highly reversible manner to the injection of various volumes and various concentrations of the electrochemical marker. For the detection of nucleic acid sequences, liposomes entrapping the electrochemical marker were tagged with a DNA probe, and superparamagnetic beads were coated with a second DNA probe. A single stranded DNA target sequence hybridized with both probes. The sandwich was captured in the microfluidic channel just upstream of the IDUA via a magnet located in the outside housing. Liposomes were lysed using a detergent and the amount of released ferro/ferricyanide was quantified while passing by the IDUA. Optimal location of the magnet with respect to the IDUA was investigated, the effect of dextran sulfate on the hybridization reaction was studied and the amount of magnetic beads used in the assay was optimized. A dose response curve using varying concentrations of target DNA molecules was carried out demonstrating a limit of

  1. A high-throughput method for GMO multi-detection using a microfluidic dynamic array.

    Science.gov (United States)

    Brod, Fábio Cristiano Angonesi; van Dijk, Jeroen P; Voorhuijzen, Marleen M; Dinon, Andréia Zilio; Guimarães, Luis Henrique S; Scholtens, Ingrid M J; Arisi, Ana Carolina Maisonnave; Kok, Esther J

    2014-02-01

    The ever-increasing production of genetically modified crops generates a demand for high-throughput DNA-based methods for the enforcement of genetically modified organisms (GMO) labelling requirements. The application of standard real-time PCR will become increasingly costly with the growth of the number of GMOs that is potentially present in an individual sample. The present work presents the results of an innovative approach in genetically modified crops analysis by DNA based methods, which is the use of a microfluidic dynamic array as a high throughput multi-detection system. In order to evaluate the system, six test samples with an increasing degree of complexity were prepared, preamplified and subsequently analysed in the Fluidigm system. Twenty-eight assays targeting different DNA elements, GM events and species-specific reference genes were used in the experiment. The large majority of the assays tested presented expected results. The power of low level detection was assessed and elements present at concentrations as low as 0.06 % were successfully detected. The approach proposed in this work presents the Fluidigm system as a suitable and promising platform for GMO multi-detection.

  2. Molecular Detection of Schistosome Infections with a Disposable Microfluidic Cassette.

    Directory of Open Access Journals (Sweden)

    Jinzhao Song

    2015-12-01

    Full Text Available Parasitic helminths such as schistosomes, as well as filarial and soil-transmitted nematodes, are estimated to infect at least a billion people worldwide, with devastating impacts on human health and economic development. Diagnosis and monitoring of infection dynamics and efficacy of treatment depend almost entirely on methods that are inaccurate, labor-intensive, and unreliable. These shortcomings are amplified and take on added significance in mass drug administration programs, where measures of effectiveness depend on accurate monitoring of treatment success (or failure, changes in disease transmission rates, and emergence of possible drug resistance. Here, we adapt isothermal molecular assays such as loop-mediated isothermal amplification (LAMP to a simple, hand-held, custom-made field-ready microfluidic device that allows sensitive and specific detection of schistosome cell-free nucleic acids in serum and plasma (separated with a point-of-care plasma separator from Schistosoma mansoni-infected mice. Cell-free S. mansoni DNA was detected with our device without prior extraction from blood. Our chip exhibits high sensitivity (~2 x 10(-17 g/μL, with a positive signal for S. mansoni DNA detectable as early as one week post infection, several weeks before parasite egg production commences. These results indicate that incorporation of isothermal amplification strategies with our chips could represent a strategy for rapid, simple, low-cost diagnosis of both pre-patent and chronic schistosome infections as well as potential monitoring of treatment efficacy.

  3. Microfluidics-Based PCR for Fusion Transcript Detection.

    Science.gov (United States)

    Chen, Hui

    2016-01-01

    The microfluidic technology allows the production of network of submillimeter-size fluidic channels and reservoirs in a variety of material systems. The microfluidic-based polymerase chain reaction (PCR) allows automated multiplexing of multiple samples and multiple assays simultaneously within a network of microfluidic channels and chambers that are co-ordinated in controlled fashion by the valves. The individual PCR reaction is performed in nanoliter volume, which allows testing on samples with limited DNA and RNA. The microfluidics devices are used in various types of PCR such as digital PCR and single molecular emulsion PCR for genotyping, gene expression, and miRNA expression. In this chapter, the use of a microfluidics-based PCR for simultaneous screening of 14 known fusion transcripts in patients with leukemia is described.

  4. An integrated microfluidic analysis microsystems with bacterial capture enrichment and in-situ impedance detection

    Science.gov (United States)

    Liu, Hai-Tao; Wen, Zhi-Yu; Xu, Yi; Shang, Zheng-Guo; Peng, Jin-Lan; Tian, Peng

    2017-09-01

    In this paper, an integrated microfluidic analysis microsystems with bacterial capture enrichment and in-situ impedance detection was purposed based on microfluidic chips dielectrophoresis technique and electrochemical impedance detection principle. The microsystems include microfluidic chip, main control module, and drive and control module, and signal detection and processing modulet and result display unit. The main control module produce the work sequence of impedance detection system parts and achieve data communication functions, the drive and control circuit generate AC signal which amplitude and frequency adjustable, and it was applied on the foodborne pathogens impedance analysis microsystems to realize the capture enrichment and impedance detection. The signal detection and processing circuit translate the current signal into impendence of bacteria, and transfer to computer, the last detection result is displayed on the computer. The experiment sample was prepared by adding Escherichia coli standard sample into chicken sample solution, and the samples were tested on the dielectrophoresis chip capture enrichment and in-situ impedance detection microsystems with micro-array electrode microfluidic chips. The experiments show that the Escherichia coli detection limit of microsystems is 5 × 104 CFU/mL and the detection time is within 6 min in the optimization of voltage detection 10 V and detection frequency 500 KHz operating conditions. The integrated microfluidic analysis microsystems laid the solid foundation for rapid real-time in-situ detection of bacteria.

  5. Electrical Impedance Spectroscopy for Detection of Cells in Suspensions Using Microfluidic Device with Integrated Microneedles

    National Research Council Canada - National Science Library

    Mansor, Muhammad; Takeuchi, Masaru; Nakajima, Masahiro; Hasegawa, Yasuhisa; Ahmad, Mohd

    2017-01-01

    .... The state of the art method for impedance flow cytometry detection utilizes an embedded electrode in the microfluidic to perform measurement of electrical impedance of the presence of cells at the sensing area...

  6. Detection of Kinase Translocation Using Microfluidic Electroporative Flow Cytometry

    Science.gov (United States)

    Lu, Chang; Wang, Jun; Bao, Ning; Paris, Leela; Wang, Hsiang-Yu; Geahlen, Robert

    2008-03-01

    Translocation of a protein between different subcellular compartments is a common event during signal transduction in living cells. Detection of these events has been largely carried out based on imaging of a low number of cells and subcellular fractionation/Western blotting. These conventional techniques either lack the high throughput desired for probing an entire cell population or provide only the average behaviors of cell populations without information from single cells. Here we demonstrate a new tool, referred to as microfluidic electroporative flow cytometry, to detect the translocation of an EGFP-tagged tyrosine kinase, Syk, to the plasma membrane in B cells at the level of the cell population. We combine electroporation with flow cytometry and observe the release of intracellular kinase out of the cells during electroporation. We found that the release of the kinase was strongly influenced by its subcellular localization. Cells stimulated through the antigen receptor have a fraction of the kinase at the plasma membrane and retain more kinase after electroporation than do cells without stimulation and translocation. This tool will have utility for kinase-related drug discovery and tumor diagnosis and staging.

  7. Microfluidics and microbial engineering.

    Science.gov (United States)

    Kou, Songzi; Cheng, Danhui; Sun, Fei; Hsing, I-Ming

    2016-02-01

    The combination of microbial engineering and microfluidics is synergistic in nature. For example, microfluidics is benefiting from the outcome of microbial engineering and many reported point-of-care microfluidic devices employ engineered microbes as functional parts for the microsystems. In addition, microbial engineering is facilitated by various microfluidic techniques, due to their inherent strength in high-throughput screening and miniaturization. In this review article, we firstly examine the applications of engineered microbes for toxicity detection, biosensing, and motion generation in microfluidic platforms. Secondly, we look into how microfluidic technologies facilitate the upstream and downstream processes of microbial engineering, including DNA recombination, transformation, target microbe selection, mutant characterization, and microbial function analysis. Thirdly, we highlight an emerging concept in microbial engineering, namely, microbial consortium engineering, where the behavior of a multicultural microbial community rather than that of a single cell/species is delineated. Integrating the disciplines of microfluidics and microbial engineering opens up many new opportunities, for example in diagnostics, engineering of microbial motors, development of portable devices for genetics, high throughput characterization of genetic mutants, isolation and identification of rare/unculturable microbial species, single-cell analysis with high spatio-temporal resolution, and exploration of natural microbial communities.

  8. Microstructure-Enhanced Liquid–Liquid Extraction in a Real-Time Fluorescence Detection Microfluidic Chip

    Directory of Open Access Journals (Sweden)

    Penghui Xiong

    2016-03-01

    Full Text Available Microfluidic system is widely employed in the detection of environmental contaminants and biological specimens. One of the critical issues which limits the applications of microfluidic chips is the limit of detection of trace specimens. Liquid–liquid extraction is of great importance in the preprocessing in microfluidic devices. In this paper, we developed a real-time fluorescence detection microfluidic chip combined with a microstructure-enhanced liquid–liquid laminar extraction technique, which concentrated the trace compound and realized real-time monitoring. Auxiliary microstructures integrated in the microfluidic chip were applied to increase the extraction efficiency, which was proved by the FEM (finite element method simulation as well. A common fluorescence probe, Rhodamine 6G (Rh6g, was used in the experiment to demonstrate the performance of the microfluidic system. It revealed that the liquid–liquid laminar extraction combined with auxiliary microstructures of a cross shape was an effective method for enrichment. The efficiency of microstructure-enhanced liquid–liquid extraction was increased by 350% compared to the traditional laminar flow extraction.

  9. Terahertz microfluidic chips for detection of amino acids in aqueous solutions

    Science.gov (United States)

    Su, Bo; Zhang, Cong; Fan, Ning; Zhang, Cunlin

    2016-11-01

    Microfluidic technology can control the fluidic thickness accurately in less than 100 micrometers. So the combination of terahertz (THz) and microfluidic technology becomes one of the most interesting directions towards biological detection. We designed microfluidic chips for terahertz spectroscopy of biological samples in aqueous solutions. Using the terahertz time-domain spectroscopy (THz-TDS) system, we experimentally measured the transmittance of the chips and the THz absorption spectra of L-threonine and L-arginine, respectively. The results indicated the feasibility of performing high sensitivity THz spectroscopy of amino acids solutions. Therefore, the microfluidic chips can realize real-time and label-free measurement for biochemistry samples in THz-TDS system.

  10. Microsphere integrated microfluidic disk: synergy of two techniques for rapid and ultrasensitive dengue detection.

    Science.gov (United States)

    Hosseini, Samira; Aeinehvand, Mohammad M; Uddin, Shah M; Benzina, Abderazak; Rothan, Hussin A; Yusof, Rohana; Koole, Leo H; Madou, Marc J; Djordjevic, Ivan; Ibrahim, Fatimah

    2015-11-09

    The application of microfluidic devices in diagnostic systems is well-established in contemporary research. Large specific surface area of microspheres, on the other hand, has secured an important position for their use in bioanalytical assays. Herein, we report a combination of microspheres and microfluidic disk in a unique hybrid platform for highly sensitive and selective detection of dengue virus. Surface engineered polymethacrylate microspheres with carefully designed functional groups facilitate biorecognition in a multitude manner. In order to maximize the utility of the microspheres' specific surface area in biomolecular interaction, the microfluidic disk was equipped with a micromixing system. The mixing mechanism (microballoon mixing) enhances the number of molecular encounters between spheres and target analyte by accessing the entire sample volume more effectively, which subsequently results in signal amplification. Significant reduction of incubation time along with considerable lower detection limits were the prime motivations for the integration of microspheres inside the microfluidic disk. Lengthy incubations of routine analytical assays were reduced from 2 hours to 5 minutes while developed system successfully detected a few units of dengue virus. Obtained results make this hybrid microsphere-microfluidic approach to dengue detection a promising avenue for early detection of this fatal illness.

  11. Microsphere integrated microfluidic disk: synergy of two techniques for rapid and ultrasensitive dengue detection

    Science.gov (United States)

    Hosseini, Samira; Aeinehvand, Mohammad M.; Uddin, Shah M.; Benzina, Abderazak; Rothan, Hussin A.; Yusof, Rohana; Koole, Leo H.; Madou, Marc J.; Djordjevic, Ivan; Ibrahim, Fatimah

    2015-11-01

    The application of microfluidic devices in diagnostic systems is well-established in contemporary research. Large specific surface area of microspheres, on the other hand, has secured an important position for their use in bioanalytical assays. Herein, we report a combination of microspheres and microfluidic disk in a unique hybrid platform for highly sensitive and selective detection of dengue virus. Surface engineered polymethacrylate microspheres with carefully designed functional groups facilitate biorecognition in a multitude manner. In order to maximize the utility of the microspheres’ specific surface area in biomolecular interaction, the microfluidic disk was equipped with a micromixing system. The mixing mechanism (microballoon mixing) enhances the number of molecular encounters between spheres and target analyte by accessing the entire sample volume more effectively, which subsequently results in signal amplification. Significant reduction of incubation time along with considerable lower detection limits were the prime motivations for the integration of microspheres inside the microfluidic disk. Lengthy incubations of routine analytical assays were reduced from 2 hours to 5 minutes while developed system successfully detected a few units of dengue virus. Obtained results make this hybrid microsphere-microfluidic approach to dengue detection a promising avenue for early detection of this fatal illness.

  12. A microfluidic device with fluorimetric detection for intracellular components analysis

    DEFF Research Database (Denmark)

    Kwapiszewski, Radosław; Skolimowski, Maciej; Ziółkowska, Karina

    2011-01-01

    An integrated microfluidic system that coupled lysis of two cell lines: L929 fibroblasts and A549 epithelial cells, with fluorescence-based enzyme assay was developed to determine β-glucocerebrosidase activity. The microdevice fabricated in poly(dimethylsiloxane) consists of three main parts: a c...

  13. Fluorescence enhancement and multiple protein detection in ZnO nanostructure microfluidic devices.

    Science.gov (United States)

    Sang, Chen-Hsiang; Chou, Shu-Jen; Pan, F M; Sheu, Jeng-Tzong

    2016-01-15

    In this study, different morphological ZnO nanostructures, those of sharp nanowires (NWs), rod NWs, and hexahedral-puncheon nanostructures, were grown in microfluidic channels on the same glass substrate. Characterizations of correspondent biomolecule binding properties were simulated and demonstrated. The surface was modified using 3-ammineopropyl-triethoxysilane (3-APTES) and biotin-N-hydroxysuccinimide ester (NHS-biotin). Different concentrations (4.17pM to 41.7nM) of dye-conjugated streptavidin were simultaneously infused through the second microfluidic channels, which lie 90° from the first microfluidic channels. The florescent intensity at the crossover areas showed good agreement with simulations, with sharp ZnO NWs exhibiting the largest dynamic range and the highest fluorescent intensity. We further characterize correspondent protein detection using sharp ZnO NWs. The surfaces of these ZnO NWs were modified with mouse immunoglobulin G (IgG), infused through the second microfluidic channels with dye-conjugated (Alexa 546) anti-mouse IgG in different concentrations. Concentrations ranging from 417fM to 41.7nM can be resolved using sharp ZnO NWs. Finally, multiple protein detection was demonstrated using a five-by-eight microfluidic channel array. Fluorescence images present clear multiple detections at the crossover areas when using the sharp ZnO NWs for simultaneous dye-conjugated anti-mouse IgG and dye-conjugated anti-rabbit IgG (Alexa 647) detection.

  14. [Micro-droplet characterization and its application for amino acid detection in droplet microfluidic system].

    Science.gov (United States)

    Yuan, Huiling; Dong, Libing; Tu, Ran; Du, Wenbin; Ji, Shiru; Wang, Qinhong

    2014-01-01

    Recently, the droplet microfluidic system attracts interests due to its high throughput and low cost to detect and screen. The picoliter micro-droplets from droplet microfluidics are uniform with respect to the size and shape, and could be used as monodispensed micro-reactors for encapsulation and detection of single cell or its metabolites. Therefore, it is indispensable to characterize micro-droplet and its application from droplet microfluidic system. We first constructed the custom-designed droplet microfluidic system for generating micro-droplets, and then used the micro-droplets to encapsulate important amino acids such as glutamic acid, phenylalanine, tryptophan or tyrosine to test the droplets' properties, including the stability, diffusivity and bio-compatibility for investigating its application for amino acid detection and sorting. The custom-designed droplet microfluidic system could generate the uniformed micro-droplets with a controllable size between 20 to 50 microm. The micro-droplets could be stable for more than 20 h without cross-contamination or fusion each other. The throughput of detection and sorting of the system is about 600 micro-droplets per minute. This study provides a high-throughput platform for the analysis and screening of amino acid-producing microorganisms.

  15. Efficient and Rapid Detection of Salmonella Using Microfluidic Impedance Based Sensing

    Directory of Open Access Journals (Sweden)

    Shibajyoti Ghosh Dastider

    2015-01-01

    Full Text Available We present a low cost, easy to fabricate biosensor, which can quickly and accurately detect Salmonella typhimurium. This study also compares the advantages of the microfluidic biosensor over a nonmicrofluidic biosensor. High density interdigitated electrode array was used to detect Salmonella cells inside a microfluidic chip. Monoclonal anti-Salmonella antibodies were allowed to be immobilized on the surface of the electrode array for selective detection of Salmonella typhimurium. An impedance analyzer was used to measure and record the response signal from the biosensor. The biosensor provides qualitative and quantitative results in 3 hours without any enrichment steps. The microfluidic biosensor’s lower detection limit was found to be 3×103 CFU/mL compared to the 3×104 CFU/mL of the nonmicrofluidic biosensor, which shows that the microfluidic biosensor has 10-fold increased sensitivity. The impedance response of microfluidic biosensor was also significantly higher (2 to 2.9 times compared to the nonmicrofluidic biosensor.

  16. Multi-Dimensional Nanostructures for Microfluidic Screening of Biomarkers: From Molecular Separation to Cancer Cell Detection.

    Science.gov (United States)

    Ng, Elaine; Chen, Kaina; Hang, Annie; Syed, Abeer; Zhang, John X J

    2016-04-01

    Rapid screening of biomarkers, with high specificity and accuracy, is critical for many point-of-care diagnostics. Microfluidics, the use of microscale channels to manipulate small liquid samples and carry reactions in parallel, offers tremendous opportunities to address fundamental questions in biology and provide a fast growing set of clinical tools for medicine. Emerging multi-dimensional nanostructures, when coupled with microfluidics, enable effective and efficient screening with high specificity and sensitivity, both of which are important aspects of biological detection systems. In this review, we provide an overview of current research and technologies that utilize nanostructures to facilitate biological separation in microfluidic channels. Various important physical parameters and theoretical equations that characterize and govern flow in nanostructure-integrated microfluidic channels will be introduced and discussed. The application of multi-dimensional nanostructures, including nanoparticles, nanopillars, and nanoporous layers, integrated with microfluidic channels in molecular and cellular separation will also be reviewed. Finally, we will close with insights on the future of nanostructure-integrated microfluidic platforms and their role in biological and biomedical applications.

  17. Optimized acoustic biochip integrated with microfluidics for biomarkers detection in molecular diagnostics.

    Science.gov (United States)

    Papadakis, G; Friedt, J M; Eck, M; Rabus, D; Jobst, G; Gizeli, E

    2017-09-01

    The development of integrated platforms incorporating an acoustic device as the detection element requires addressing simultaneously several challenges of technological and scientific nature. The present work was focused on the design of a microfluidic module, which, combined with a dual or array type Love wave acoustic chip could be applied to biomedical applications and molecular diagnostics. Based on a systematic study we optimized the mechanics of the flow cell attachment and the sealing material so that fluidic interfacing/encapsulation would impose minimal losses to the acoustic wave. We have also investigated combinations of operating frequencies with waveguide materials and thicknesses for maximum sensitivity during the detection of protein and DNA biomarkers. Within our investigations neutravidin was used as a model protein biomarker and unpurified PCR amplified Salmonella DNA as the model genetic target. Our results clearly indicate the need for experimental verification of the optimum engineering and analytical parameters, in order to develop commercially viable systems for integrated analysis. The good reproducibility of the signal together with the ability of the array biochip to detect multiple samples hold promise for the future use of the integrated system in a Lab-on-a-Chip platform for application to molecular diagnostics.

  18. Development and characterization of a microfluidic glucose sensing system based on an enzymatic microreactor and chemiluminescence detection

    NARCIS (Netherlands)

    Moon, B. -U; de Vries, M. G.; Westerink, B. H. C.; Verpoorte, E.

    2012-01-01

    Chemiluminescence detection was developed as an alternative to amperometric detection for glucose analysis in a portable, microfluidics-based continuous glucose monitoring system. Amperometric detection allows easy determination of hydrogen peroxide, a product of the glucose oxidase-catalyzed reacti

  19. Development and characterization of a microfluidic glucose sensing system based on an enzymatic microreactor and chemiluminescence detection

    NARCIS (Netherlands)

    Moon, B. -U; de Vries, M. G.; Westerink, B. H. C.; Verpoorte, E.

    Chemiluminescence detection was developed as an alternative to amperometric detection for glucose analysis in a portable, microfluidics-based continuous glucose monitoring system. Amperometric detection allows easy determination of hydrogen peroxide, a product of the glucose oxidase-catalyzed

  20. Microvalve Enabled Digital Microfluidic Systems for High Performance Biochemical and Genetic Analysis.

    Science.gov (United States)

    Jensen, Erik C; Zeng, Yong; Kim, Jungkyu; Mathies, Richard A

    2010-12-01

    Microfluidic devices offer unparalleled capability for digital microfluidic automation of sample processing and complex assay protocols in medical diagnostic and research applications. In our own work, monolithic membrane valves have enabled the creation of two platforms that precisely manipulate discrete, nanoliter-scale volumes of sample. The digital microfluidic Automaton uses two-dimensional microvalve arrays to combinatorially process nanoliter-scale sample volumes. This programmable system enables rapid integration of diverse assay protocols using a universal processing architecture. Microfabricated emulsion generator array (MEGA) devices integrate actively controlled 3-microvalve pumps to enable on-demand generation of uniform droplets for statistical encapsulation of microbeads and cells. A MEGA device containing 96 channels confers the capability of generating up to 3.4 × 10(6) nanoliter-volume droplets per hour for ultrahigh-throughput detection of rare mutations in a vast background of normal genotypes. These novel digital microfluidic platforms offer significant enhancements in throughput, sensitivity, and programmability for automated sample processing and analysis.

  1. A portable and power-free microfluidic device for rapid and sensitive lead (Pb2+) detection.

    Science.gov (United States)

    Fan, Chunhui; He, Shijiang; Liu, Gang; Wang, Lianhui; Song, Shiping

    2012-01-01

    A portable and power-free microfluidic device was designed for rapid and sensitive detection of lead (Pb(2+)). 11-mercaptoundecanoic acid (MUA)-functionalized gold nanoparticles (MUA-AuNPs) aggregated in the presence of Pb(2+) for the chelation mechanism. When we performed this analysis on a polydimethylsiloxane (PDMS) microfluidic chip, the aggregations deposited onto the surface of chip and formed dark lines along the laminar flows in the zigzag microchannels. This visual result can be observed by the naked eye through a microscope or just a drop of water as a magnifier. Ten μM Pb(2+) was successfully detected.

  2. Integrating Electrochemical Detection with Centrifugal Microfluidics for Real-Time and Fully Automated Sample Testing

    DEFF Research Database (Denmark)

    Andreasen, Sune Zoëga; Kwasny, Dorota; Amato, Letizia;

    2015-01-01

    Here we present a robust, stable and low-noise experimental set-up for performing electrochemical detection on a centrifugal microfluidic platform. By using a low-noise electronic component (electrical slip-ring) it is possible to achieve continuous, on-line monitoring of electrochemical experime......Here we present a robust, stable and low-noise experimental set-up for performing electrochemical detection on a centrifugal microfluidic platform. By using a low-noise electronic component (electrical slip-ring) it is possible to achieve continuous, on-line monitoring of electrochemical...

  3. Optical hyperpolarization and NMR detection of $^{129}$Xe on a microfluidic chip

    CERN Document Server

    Jimenez-Martinez, Ricardo; Rosenbluh, Michael; Donley, Elizabeth A; Knappe, Svenja; Seltzer, Scott J; Ring, Hattie L; Bajaj, Vikram S; Kitching, John

    2014-01-01

    Optically hyperpolarized $^{129}$Xe gas has become a powerful contrast agent in nuclear magnetic resonance (NMR) spectroscopy and imaging, with applications ranging from studies of the human lung to the targeted detection of biomolecules. Equally attractive is its potential use to enhance the sensitivity of microfluidic NMR experiments, in which small sample volumes yield poor sensitivity. Unfortunately, most $^{129}$Xe polarization systems are large and non-portable. Here we present a microfabricated chip that optically polarizes $^{129}$Xe gas. We have achieved $^{129}$Xe polarizations greater than 0.5$\\%$ at flow rates of several microliters per second, compatible with typical microfluidic applications. We employ in situ optical magnetometry to sensitively detect and characterize the $^{129}$Xe polarization at magnetic fields of 1 $\\mu$T. We construct the device using standard microfabrication techniques, which will facilitate its integration with existing microfluidic platforms. This device may enable the...

  4. Microfluidic chip-based silver nanoparticles aptasensor for colorimetric detection of thrombin.

    Science.gov (United States)

    Zhao, Yaju; Liu, Xiaohui; Li, Jie; Qiang, Weibing; Sun, Liang; Li, Hui; Xu, Danke

    2016-04-01

    In this paper, a colorimetric silver nanoparticles aptasensor (aptamer-AgNPs) was developed for simple and straightforward detection of protein in microfluidic chip. Surface-functionalized microfluidic channels were employed as the capture platform. Then the mixture of target protein and aptamer-AgNPs were injected into the microfluidic channels for colorimetric detection. To demonstrate the performance of this detection platform, thrombin was chosen as a model target protein. Introduction of thrombin could form a sandwich-type complex involving immobilized AgNPs. The amount of aptamer-AgNPs on the complex augmented along with the increase of the thrombin concentration causing different color change that can be analyzed both by naked eyes and a flatbed scanner. This method is featured with low sample consumption, simple processes of microfluidic platform and straightforward colorimetric detection with aptamer-AgNPs. Thrombin at concentrations as low as 20pM can be detected using this aptasensor without signal amplification. This work demonstrated that it had good selectivity over other proteins and it could be a useful strategy to detect other targets with two affinity binding sites for ligands as well.

  5. Graphene nano-ink biosensor arrays on a microfluidic paper for multiplexed detection of metabolites

    Energy Technology Data Exchange (ETDEWEB)

    Labroo, Pratima; Cui, Yue, E-mail: yue.cui@usu.edu

    2014-02-01

    Graphical abstract: - Highlights: • We report graphene-ink biosensor arrays on a microfluidic paper for metabolites. • The device is able to detect multiple metabolites sensitively and rapidly. • The device fabrication process is simple and inexpensive. - Abstract: The development of a miniaturized and low-cost platform for the highly sensitive, selective and rapid detection of multiplexed metabolites is of great interest for healthcare, pharmaceuticals, food science, and environmental monitoring. Graphene is a delicate single-layer, two-dimensional network of carbon atoms with extraordinary electrical sensing capability. Microfluidic paper with printing technique is a low cost matrix. Here, we demonstrated the development of graphene-ink based biosensor arrays on a microfluidic paper for the multiplexed detection of different metabolites, such as glucose, lactate, xanthine and cholesterol. Our results show that the graphene biosensor arrays can detect multiple metabolites on a microfluidic paper sensitively, rapidly and simultaneously. The device exhibits a fast measuring time of less than 2 min, a low detection limit of 0.3 μM, and a dynamic detection range of 0.3–15 μM. The process is simple and inexpensive to operate and requires a low consumption of sample volume. We anticipate that these results could open exciting opportunities for a variety of applications.

  6. A zero-flow microfluidics for long-term cell culture and detection

    Directory of Open Access Journals (Sweden)

    Shengbo Sang

    2015-04-01

    Full Text Available A zero-flow microfluidic design is proposed in this paper, which can be used for long-term cell culture and detection, especially for a lab-on-chip integrated with a biosensor. It consists of two parts: a main microchannel; and a circle microchamber. The Finite Element Method (FEM was employed to predict the fluid transport properties for a minimum fluid flow disturbance. Some commonly used microfluidic structures were also analysed systematically to prove the designed structure. Then the designed microfluidics was fabricated. Based on the simulations and experiments, this design provides a continuous flow environment, with a relatively stable and low shear stress atmosphere, similar to a zero-flow environment. Furthermore, the nutrients maintaining cells’ normal growth can be taken into the chamber through the diffusion effect. It also proves that the microfluidics can realize long-term cell culture and detection. The application of the structure in the field of biological microelectromechenical systems (BioMEMS will provide a research foundation for microfluidic technology.

  7. A zero-flow microfluidics for long-term cell culture and detection

    Science.gov (United States)

    Sang, Shengbo; Tang, Xiaoliang; Feng, Qiliang; Jian, Aoqun; Zhang, Wendong

    2015-04-01

    A zero-flow microfluidic design is proposed in this paper, which can be used for long-term cell culture and detection, especially for a lab-on-chip integrated with a biosensor. It consists of two parts: a main microchannel; and a circle microchamber. The Finite Element Method (FEM) was employed to predict the fluid transport properties for a minimum fluid flow disturbance. Some commonly used microfluidic structures were also analysed systematically to prove the designed structure. Then the designed microfluidics was fabricated. Based on the simulations and experiments, this design provides a continuous flow environment, with a relatively stable and low shear stress atmosphere, similar to a zero-flow environment. Furthermore, the nutrients maintaining cells' normal growth can be taken into the chamber through the diffusion effect. It also proves that the microfluidics can realize long-term cell culture and detection. The application of the structure in the field of biological microelectromechenical systems (BioMEMS) will provide a research foundation for microfluidic technology.

  8. Microfluidics & nanotechnology: Towards fully integrated analytical devices for the detection of cancer biomarkers

    KAUST Repository

    Perozziello, Gerardo

    2014-01-01

    In this paper, we describe an innovative modular microfluidic platform allowing filtering, concentration and analysis of peptides from a complex mixture. The platform is composed of a microfluidic filtering device and a superhydrophobic surface integrating surface enhanced Raman scattering (SERS) sensors. The microfluidic device was used to filter specific peptides (MW 1553.73 D) derived from the BRCA1 protein, a tumor-suppressor molecule which plays a pivotal role in the development of breast cancers, from albumin (66.5 KD), the most represented protein in human plasma. The filtering process consisted of driving the complex mixture through a porous membrane having a cut-off of 12-14 kD by hydrodynamic flow. The filtered samples coming out of the microfluidic device were subsequently deposited on a superhydrophobic surface formed by micro pillars on top of which nanograins were fabricated. The nanograins coupled to a Raman spectroscopy instrument acted as a SERS sensor and allowed analysis of the filtered sample on top of the surface once it evaporated. By using the presented platform, we demonstrate being able to sort small peptides from bigger proteins and to detect them by using a label-free technique at a resolution down to 0.1 ng μL-1. The combination of microfluidics and nanotechnology to develop the presented microfluidic platform may give rise to a new generation of biosensors capable of detecting low concentration samples from complex mixtures without the need for any sample pretreatment or labelling. The developed devices could have future applications in the field of early diagnosis of severe illnesses, e.g. early cancer detection. This journal is

  9. A microfluidic nano-biosensor for the detection of pathogenic Salmonella.

    Science.gov (United States)

    Kim, Giyoung; Moon, Ji-Hea; Moh, Chang-Yeon; Lim, Jong-guk

    2015-05-15

    Rapid detection of pathogenic Salmonella in food products is extremely important for protecting the public from salmonellosis. The objective of the present study was to explore the feasibility of using a microfluidic nano-biosensor to rapidly detect pathogenic Salmonella. Quantum dot nanoparticles were used to detect Salmonella cells. For selective detection of Salmonella, anti-Salmonella polyclonal antibodies were covalently immobilized onto the quantum dot surface. To separate and concentrate the cells from the sample, superparamagnetic particles and a microfluidic chip were used. A portable fluorometer was developed to measure the fluorescence signal from the quantum dot nanoparticles attached to Salmonella in the samples. The sensitivity for detection of pathogenic Salmonella was evaluated using serially diluted Salmonella Typhimurium in borate buffer and chicken extract. The fluorescence response of the nano-biosensor increased with increasing cell concentration. The detection limit of the sensor was 10(3) CFU/mL Salmonella in both borate buffer and food extract.

  10. Manufacturing and testing flexible microfluidic devices with optical and electrical detection mechanisms

    NARCIS (Netherlands)

    Ivan, M.G.; Vivet, F.; Meinders, E.R.

    2010-01-01

    Flexible microfluidic devices made of poly(dimethylsiloxane) (PDMS) were manufactured by soft lithography, and tested in detection of ionic species using optical absorption spectroscopy and electrical measurements. PDMS was chosen due to its flexibility and ease of surface modification by exposure

  11. A Novel Impedimetric Microfluidic Analysis System for Transgenic Protein Cry1Ab Detection

    Science.gov (United States)

    Jin, Shunru; Ye, Zunzhong; Wang, Yixian; Ying, Yibin

    2017-01-01

    Impedimetric analysis method is an important tool for food safety detection. In this work, a novel impedimetric microfluidic analysis system consisted of a printed gold electrode chip and a microfluidic flow cell was developed for sensitive and selective detection of transgenic protein Cry1Ab. Anti-Cry1Ab aptamer coated magnetic beads were used to recognize transgenic protein Cry1Ab and form Cry1Ab-aptamer modified magnetic beads. After separation, the obtained Cry1Ab-aptamer modified magnetic beads were dissolved in 0.01 M mannitol and followed by injection into the microfluidic flow cell for impedimetric measurement. At the frequency of 358.3 Hz, the impedance signal shows a good linearity with the concentrations of Cry1Ab protein at a range from 0 to 0.2 nM, and the detection limit is 0.015 nM. The results demonstrate that the impedimetric microfluidic analysis system provides an alternative way to enable sensitive, rapid and specific detection of transgenic protein Cry1Ab. PMID:28251986

  12. Design of a confocal microfluidic particle sorter using fluorescent photon burst detection

    NARCIS (Netherlands)

    Kunst, B.H.; Schots, A.; Visser, A.J.W.G.

    2004-01-01

    An instrumental system is described for detecting and sorting single fluorescent particles such as microspheres, bacteria, viruses, or even smaller macromolecules in a flowing liquid. The system consists of microfluidic chips (biochips), computer controlled high voltage power supplies, and a fluores

  13. Manufacturing and testing flexible microfluidic devices with optical and electrical detection mechanisms

    NARCIS (Netherlands)

    Ivan, M.G.; Vivet, F.; Meinders, E.R.

    2010-01-01

    Flexible microfluidic devices made of poly(dimethylsiloxane) (PDMS) were manufactured by soft lithography, and tested in detection of ionic species using optical absorption spectroscopy and electrical measurements. PDMS was chosen due to its flexibility and ease of surface modification by exposure t

  14. Extraction, amplification and detection of DNA in microfluidic chip-based assays

    KAUST Repository

    Wu, Jinbo

    2013-12-20

    This review covers three aspects of PCR-based microfluidic chip assays: sample preparation, target amplification, and product detection. We also discuss the challenges related to the miniaturization and integration of each assay and make a comparison between conventional and microfluidic schemes. In order to accomplish these essential assays without human intervention between individual steps, the micro-components for fluid manipulation become critical. We therefore summarize and discuss components such as microvalves (for fluid regulation), pumps (for fluid driving) and mixers (for blending fluids). By combining the above assays and microcomponents, DNA testing of multi-step bio-reactions in microfluidic chips may be achieved with minimal external control. The combination of assay schemes with the use of micro-components also leads to rapid methods for DNA testing via multi-step bioreactions. Contains 259 references.

  15. Electrochemical detection on electrowetting-on-dielectric digital microfluidic chip.

    Science.gov (United States)

    Karuwan, Chanpen; Sukthang, Kreeta; Wisitsoraat, Anurat; Phokharatkul, Ditsayut; Patthanasettakul, Viyapol; Wechsatol, Wishsanuruk; Tuantranont, Adisorn

    2011-06-15

    In this work, the use of three-electrode electrochemical sensing system with an electrowetting-on-dielectric (EWOD) digital microfluidic device is reported for quantitative analysis of iodide. T-junction EWOD mixer device was designed using arrays of 50-μm spaced square electrodes for mixing buffer reagent and analyte droplets. For fabrication of EWOD chips, 5-μm thick silver EWOD electrodes were formed on a glass substrate by means of sputtering and lift-off process. PDMS and Teflon thin films were then coated on the electrodes by spin coating to yield hydrophobic surface. An external three-electrode system consisting of Au working, Ag reference and Pt auxiliary wires were installed over EWOD electrodes at the end of T-junction mixer. In experiment, a few-microliter droplets of Tris buffer and iodide solutions were moved toward the mixing junction and transported toward electrochemical electrodes by EWOD process. A short processing time within seconds was achieved at EWOD applied voltage of 300V. The analyte droplets mixed with different concentrations were successfully analyzed by cyclic voltametry. Therefore, the combination of EWOD digital microfluidic and electrochemical sensing system has successfully been demonstrated for rapid chemical analysis with minimal reagent consumption.

  16. Micro-total analysis system for virus detection: microfluidic pre-concentration coupled to liposome-based detection.

    Science.gov (United States)

    Connelly, John T; Kondapalli, Sowmya; Skoupi, Marc; Parker, John S L; Kirby, Brian J; Baeumner, Antje J

    2012-01-01

    An integrated microfluidic biosensor is presented that combines sample pre-concentration and liposome-based signal amplification for the detection of enteric viruses present in environmental water samples. This microfluidic approach overcomes the challenges of long assay times of cell culture-based methods and the need to extensively process water samples to eliminate inhibitors for PCR-based methods. Here, viruses are detected using an immunoassay sandwich approach with the reporting antibodies tagged to liposomes. Described is the development of the integrated device for the detection of environmentally relevant viruses using feline calicivirus (FCV) as a model organism for human norovirus. In situ fabricated nanoporous membranes in glass microchannels were used in conjunction with electric fields to achieve pre-concentration of virus-liposome complexes and therefore enhance the antibody-virus binding efficiency. The concentrated complexes were eluted to a detection region downstream where captured liposomes were lysed to release fluorescent dye molecules that were then quantified using image processing. This system was compared to an optimized electrochemical liposome-based microfluidic biosensor without pre-concentration. The limit of detection of FCV of the integrated device was at 1.6 × 10(5) PFU/mL, an order of magnitude lower than that obtained using the microfluidic biosensor without pre-concentration. This significant improvement is a key step toward the goal of using this integrated device as an early screening system for viruses in environmental water samples.

  17. On-chip quantitative detection of pathogen genes by autonomous microfluidic PCR platform.

    Science.gov (United States)

    Tachibana, Hiroaki; Saito, Masato; Shibuya, Shogo; Tsuji, Koji; Miyagawa, Nobuyuki; Yamanaka, Keiichiro; Tamiya, Eiichi

    2015-12-15

    Polymerase chain reaction (PCR)-based genetic testing has become a routine part of clinical diagnoses and food testing. In these fields, rapid, easy-to-use, and cost-efficient PCR chips are expected to be appeared for providing such testing on-site. In this study, a new autonomous disposable plastic microfluidic PCR chip was created, and was utilized for quantitative detection of pathogenic microorganisms. To control the capillary flow of the following solution in the PCR microchannel, a driving microchannel was newly designed behind the PCR microchannel. This allowed the effective PCR by simply dropping the PCR solution onto the inlet without any external pumps. In order to achieve disposability, injection-molded cyclo-olefin polymer (COP) of a cost-competitive plastic was used for the PCR chip. We discovered that coating the microchannel walls with non-ionic surfactant produced a suitable hydrophilic surface for driving the capillary flow through the 1250-mm long microchannel. As a result, quantitative real-time PCR with the lowest initial concentration of human, Escherichia coli (E. coli), and pathogenic E. coli O157 genomic DNA of 4, 0.0019, 0.031 pg/μl, respectively, was successfully achieved in less than 18 min. Our results indicate that the platform presented in this study provided a rapid, easy-to-use, and low-cost real-time PCR system that could be potentially used for on-site gene testing.

  18. Fluorescence Detection 400–480 nm Using Microfluidic System Integrated GaP Photodiodes

    Directory of Open Access Journals (Sweden)

    Dion McIntosh

    2011-01-01

    Full Text Available Ciprofloxacin is a commonly used antibiotic and the active ingredient in a veterinary antibiotic. Detecting its presence allows us to understand its absorption process in blood as well as tissue. A portable microfluidic system has been fabricated. It operates at low bias voltage and shows a linear relationship between concentration levels and system response. Detection of concentrations down to 1 ppb of ciprofloxacin in microliters of solution was achieved.

  19. Detecting transforming growth factor-β release from liver cells using an aptasensor integrated with microfluidics.

    Science.gov (United States)

    Matharu, Zimple; Patel, Dipali; Gao, Yandong; Haque, Amranul; Zhou, Qing; Revzin, Alexander

    2014-09-02

    We developed a cell-culture/biosensor platform consisting of aptamer-modified Au electrodes integrated with reconfigurable microfluidics for monitoring of transforming growth factor-beta 1 (TGF-β1), an important inflammatory and pro-fibrotic cytokine. Aptamers were thiolated, labeled with redox reporters, and self-assembled on gold surfaces. The biosensor was determined to be specific for TGF-β1 with an experimental detection limit of 1 ng/mL and linear range extending to 250 ng/mL. Upon determining figures of merit, aptasensor was miniaturized and integrated with human hepatic stellate cells inside microfluidic devices. Reconfigurable microfluidics were developed to ensure that seeding of "sticky" stromal cells did not foul the electrode and compromise sensor performance. This microsystem with integrated aptasensors was used to monitor TGF-β1 release from activated stellate cells over the course of 20 h. The electrochemical response went down upon infusing anti-TGF-β1 antibodies into the microfluidic devices containing activated stellate cells. To further validate aptasensor responses, stellate cells were stained for markers of activation (e.g., alpha smooth muscle actin) and were also tested for presence of TGF-β1 using enzyme linked immunosorbent assay (ELISA). Given the importance of TGF-β1 as a fibrogenic signal, a microsystem with integrated biosensors for local and continuous detection of TGF-β1 may prove to be an important tool to study fibrosis of the liver and other organs.

  20. Microfluidic cell culture and metabolism detection with electrospray ionization quadrupole time-of-flight mass spectrometer.

    Science.gov (United States)

    Gao, Dan; Wei, Huibin; Guo, Guang-Sheng; Lin, Jin-Ming

    2010-07-01

    A novel method for the characterization of drug metabolites was developed by integrating chip-based solid-phase extraction (SPE) with an online electrospray ionization quadrupole time-of-fight mass spectrometer (ESI-Q-TOF-MS). The integrated microfluidic device was composed of circular chambers for cell culture and straight microchannels with shrink ends to pack the solid-phase material for sample cleanup and concentration prior to mass analysis. By connecting the two separated microchannels with polyethylene tubes, drug metabolism studies related to functional units, including cell culture, metabolism generation, sample pretreatment, and detection, were all integrated into the microfluidic device. To verify the feasibility of a drug metabolism study on the microfluidic device, the metabolism of vitamin E in human lung epithelial A549 cells was studied. The metabolites were successfully detected by online ESI-Q-TOF-MS with high sensitivity and short analysis time (8 min). By integrating several parallel channels, the desalting and concentration process could be simultaneously achieved. The total sample pretreatment time only needed about 15 min, and solvent consumption could be reduced to less than 100 microL. All this demonstrated that the developed microfluidic device could be a potential useful tool for cellular drug metabolism research.

  1. Enzyme incorporated microfluidic device for in-situ glucose detection in water-in-air microdroplets.

    Science.gov (United States)

    Piao, Yunxian; Han, Dong Ju; Azad, Mohammad Reza; Park, Minsu; Seo, Tae Seok

    2015-03-15

    Droplet generating microfluidic systems can provide miniaturized bioanalytical tools by using the homogenous and high-throughput droplets as nanoreactors. In this study, we demonstrated a sensitive and in-situ glucose monitoring system using water-in-air droplets in an enzyme incorporated microfluidic device. A thin film structure of a glucose oxidase (GOx) enzyme immobilized hydrogel was constructed in the middle of the microfluidic channel, and nanoliter scaled water-in-air droplets which contain a glucose sample, horseradish peroxidase (HRP), and an Amplex Red substrate were generated by flow focusing of water phase with air. Once the droplets passed through the enzyme trapped hydrogel, the droplets temporarily halted and a GOx mediated catalytic reaction with glucose proceeded, resulting in producing fluorescent resorufin products in the droplets. With optimized conditions such as the thickness of a hydrogel film and the size and flowing rate of droplets, fluorescence intensities of the released droplets linearly increased in proportional to the glucose concentration up to 3mM, and the limit of detection was calculated as 6.64µM. A spiked glucose in a real urine sample was also successfully analyzed, and the functionality of the proposed enzyme immobilized microfluidic chip was maintained for at least two weeks without loss of enzymatic activity and detection sensitivity. Thus, our methodology suggests a novel droplet based glucose sensing chip which can monitor glucose in a real-time and high-throughput manner.

  2. Integrating printed microfluidics with silicon photomultipliers for miniaturised and highly sensitive ATP bioluminescence detection.

    Science.gov (United States)

    Santangelo, M F; Libertino, S; Turner, A P F; Filippini, D; Mak, W C

    2018-01-15

    Bioluminescence has been widely used for important biosensing applications such as the measurement of adenosine triphosphate (ATP), the energy unit in biological systems and an indicator of vital processes. The current technology for detection is mainly based on large equipment such as readers and imaging systems, which require intensive and time-consuming procedures. A miniaturised bioluminescence sensing system, which would allow sensitive and continuous monitoring of ATP, with an integrated and low-cost disposable microfluidic chamber for handling of biological samples, is highly desirable. Here, we report the design, fabrication and testing of 3D printed microfluidics chips coupled with silicon photomultipliers (SiPMs) for high sensitive real-time ATP detection. The 3D microfluidic chip reduces reactant consumption and facilitates solution delivery close to the SiPM to increase the detection efficiency. Our system detects ATP with a limit of detection (LoD) of 8nM and an analytical dynamic range between 15nM and 1µM, showing a stability error of 3%, and a reproducibility error below of 20%. We demonstrate the dynamic monitoring of ATP in a continuous-flow system exhibiting a fast response time, ~4s, and a full recovery to the baseline level within 17s. Moreover, the SiPM-based bioluminescence sensing system shows a similar analytical dynamic range for ATP detection to that of a full-size PerkinElmer laboratory luminescence reader. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. An integrated rotary microfluidic system with DNA extraction, loop-mediated isothermal amplification, and lateral flow strip based detection for point-of-care pathogen diagnostics.

    Science.gov (United States)

    Park, Byung Hyun; Oh, Seung Jun; Jung, Jae Hwan; Choi, Goro; Seo, Ji Hyun; Kim, Do Hyun; Lee, Eun Yeol; Seo, Tae Seok

    2017-05-15

    Point-of-care (POC) molecular diagnostics plays a pivotal role for the prevention and treatment of infectious diseases. In spite of recent advancement in microfluidic based POC devices, there are still rooms for development to realize rapid, automatic and cost-effective sample-to-result genetic analysis. In this study, we propose an integrated rotary microfluidic system that is capable of performing glass microbead based DNA extraction, loop mediated isothermal amplification (LAMP), and colorimetric lateral flow strip based detection in a sequential manner with an optimized microfluidic design and a rotational speed control. Rotation direction-dependent coriolis force and siphon valving structures enable us to perform the fluidic control and metering, and the use of the lateral flow strip as a detection method renders all the analytical processes for nucleic acid test simplified and integrated without the need of expensive instruments or human intervention. As a proof of concept for point-of-care DNA diagnostics, we identified the food-borne bacterial pathogen which was contaminated in water or milk. Not only monoplex Salmonella Typhimurium but also multiplex Salmonella Typhimurium and Vibrio parahaemolyticus were analysed on the integrated rotary genetic analysis microsystem with a limit of detection of 50 CFU in 80min. In addition, three multiple samples were simultaneously analysed on a single device. The sample-to-result capability of the proposed microdevice provides great usefulness in the fields of clinical diagnostics, food safety and environment monitoring.

  4. Microfluidics for rapid detection of isocitrate dehydrogenase 1 mutation for intraoperative application.

    Science.gov (United States)

    Aibaidula, Abudumijiti; Zhao, Wang; Wu, Jin-Song; Chen, Hong; Shi, Zhi-Feng; Zheng, Lu-Lu; Mao, Ying; Zhou, Liang-Fu; Sui, Guo-Dong

    2016-06-01

    OBJECT Conventional methods for isocitrate dehydrogenase 1 (IDH1) detection, such as DNA sequencing and immunohistochemistry, are time- and labor-consuming and cannot be applied for intraoperative analysis. To develop a new approach for rapid analysis of IDH1 mutation from tiny tumor samples, this study used microfluidics as a method for IDH1 mutation detection. METHODS Forty-seven glioma tumor samples were used; IDH1 mutation status was investigated by immunohistochemistry and DNA sequencing. The microfluidic device was fabricated from polydimethylsiloxane following standard soft lithography. The immunoanalysis was conducted in the microfluidic chip. Fluorescence images of the on-chip microcolumn taken by the charge-coupled device camera were collected as the analytical results readout. Fluorescence signals were analyzed by NIS-Elements software to gather detailed information about the IDH1 concentration in the tissue samples. RESULTS DNA sequencing identified IDH1 R132H mutation in 33 of 47 tumor samples. The fluorescence signal for IDH1-mutant samples was 5.49 ± 1.87 compared with 3.90 ± 1.33 for wild type (p = 0.005). Thus, microfluidics was capable of distinguishing IDH1-mutant tumor samples from wild-type samples. When the cutoff value was 4.11, the sensitivity of microfluidics was 87.9% and the specificity was 64.3%. CONCLUSIONS This new approach was capable of analyzing IDH1 mutation status of tiny tissue samples within 30 minutes using intraoperative microsampling. This approach might also be applied for rapid pathological diagnosis of diffuse gliomas, thus guiding personalized resection.

  5. Nucleic Acid-based Detection of Bacterial Pathogens Using Integrated Microfluidic Platform Systems

    Directory of Open Access Journals (Sweden)

    Carl A. Batt

    2009-05-01

    Full Text Available The advent of nucleic acid-based pathogen detection methods offers increased sensitivity and specificity over traditional microbiological techniques, driving the development of portable, integrated biosensors. The miniaturization and automation of integrated detection systems presents a significant advantage for rapid, portable field-based testing. In this review, we highlight current developments and directions in nucleic acid-based micro total analysis systems for the detection of bacterial pathogens. Recent progress in the miniaturization of microfluidic processing steps for cell capture, DNA extraction and purification, polymerase chain reaction, and product detection are detailed. Discussions include strategies and challenges for implementation of an integrated portable platform.

  6. Gene Detection in Complex Biological Media Using Semiconductor Nanorods within an Integrated Microfluidic Device.

    Science.gov (United States)

    Bi, Xinyan; Adriani, Giulia; Xu, Yang; Chakrabortty, Sabyasachi; Pastorin, Giorgia; Ho, Han Kiat; Ang, Wee Han; Chan, Yinthai

    2015-10-20

    The salient optical properties of highly luminescent semiconductor nanocrystals render them ideal fluorophores for clinical diagnostics, therapeutics, and highly sensitive biochip applications. Microfluidic systems allow miniaturization and integration of multiple biochemical processes in a single device and do not require sophisticated diagnostic tools. Herein, we describe a microfluidic system that integrates RNA extraction, reverse transcription to cDNA, amplification and detection within one integrated device to detect histidine decarboxylase (HDC) gene directly from human white blood cells samples. When anisotropic semiconductor nanorods (NRs) were used as the fluorescent probes, the detection limit was found to be 0.4 ng of total RNA, which was much lower than that obtained using spherical quantum dots (QDs) or organic dyes. This was attributed to the large action cross-section of NRs and their high probability of target capture in a pull-down detection scheme. The combination of large scale integrated microfluidics with highly fluorescent semiconductor NRs may find widespread utility in point-of-care devices and multitarget diagnostics.

  7. Rapid Microfluidic Assay for the Detection of Botulinum Neurotoxin in Animal Sera

    Directory of Open Access Journals (Sweden)

    Lmar Babrak

    2016-01-01

    Full Text Available Potent Botulinum neurotoxins (BoNTs represent a threat to public health and safety. Botulism is a disease caused by BoNT intoxication that results in muscle paralysis that can be fatal. Sensitive assays capable of detecting BoNTs from different substrates and settings are essential to limit foodborne contamination and morbidity. In this report, we describe a rapid 96-well microfluidic double sandwich immunoassay for the sensitive detection of BoNT-A from animal sera. This BoNT microfluidic assay requires only 5 μL of serum, provides results in 75 min using a standard fluorescence microplate reader and generates minimal hazardous waste. The assay has a <30 pg·mL−1 limit of detection (LOD of BoNT-A from spiked human serum. This sensitive microfluidic BoNT-A assay offers a fast and simplified workflow suitable for the detection of BoNT-A from serum samples of limited volume in most laboratory settings.

  8. A fluorescence-based centrifugal microfluidic system for parallel detection of multiple allergens

    Science.gov (United States)

    Chen, Q. L.; Ho, H. P.; Cheung, K. L.; Kong, S. K.; Suen, Y. K.; Kwan, Y. W.; Li, W. J.; Wong, C. K.

    2010-02-01

    This paper reports a robust polymer based centrifugal microfluidic analysis system that can provide parallel detection of multiple allergens in vitro. Many commercial food products (milk, bean, pollen, etc.) may introduce allergy to people. A low-cost device for rapid detection of allergens is highly desirable. With this as the objective, we have studied the feasibility of using a rotating disk device incorporating centrifugal microfluidics for performing actuationfree and multi-analyte detection of different allergen species with minimum sample usage and fast response time. Degranulation in basophils or mast cells is an indicator to demonstrate allergic reaction. In this connection, we used acridine orange (AO) to demonstrate degranulation in KU812 human basophils. It was found that the AO was released from granules when cells were stimulated by ionomycin, thus signifying the release of histamine which accounts for allergy symptoms [1-2]. Within this rotating optical platform, major microfluidic components including sample reservoirs, reaction chambers, microchannel and flow-control compartments are integrated into a single bio-compatible polydimethylsiloxane (PDMS) substrate. The flow sequence and reaction time can be controlled precisely. Sequentially through varying the spinning speed, the disk may perform a variety of steps on sample loading, reaction and detection. Our work demonstrates the feasibility of using centrifugation as a possible immunoassay system in the future.

  9. A portable microfluidic flow cytometer based on simultaneous detection of impedance and fluorescence.

    Science.gov (United States)

    Joo, Segyeong; Kim, Kee Hyun; Kim, Hee Chan; Chung, Taek Dong

    2010-02-15

    A portable microfluidic flow cytometer with dual detection ability of impedance and fluorescence was developed for cell analysis and particle-based assays. In the proposed system, fluorescence from microparticles and cells is measured through excitation by a light emitting diode (LED) and detection by a solid-stated photomultiplier (SSPM). Simultaneous impedometric detection provides information on the existence and size of microparticles and cells through polyelectrolyte gel electrodes (PGEs) operated by custom designed circuits for signal detection, amplification, and conversion. Fluorescence and impedance signals were sampled at 1 kHz with 12 bit resolution. The resulting microfluidic cytometer is 15x10x10 cm(3) in width, depth, and height, with a weight of about 800 g. Such a miniaturized and battery powered system yielded a portable microfluidic cytometer with high performance. Various microbeads and human embryonic kidney 293 (HEK-293) cells were employed to evaluate the system. Impedance and fluorescence signals from each bead or cell made classification of micro particles or cells easy and fast.

  10. Optical fiber LPG biosensor integrated microfluidic chip for ultrasensitive glucose detection.

    Science.gov (United States)

    Yin, Ming-Jie; Huang, Bobo; Gao, Shaorui; Zhang, A Ping; Ye, Xuesong

    2016-05-01

    An optical fiber sensor integrated microfluidic chip is presented for ultrasensitive detection of glucose. A long-period grating (LPG) inscribed in a small-diameter single-mode fiber (SDSMF) is employed as an optical refractive-index (RI) sensor. With the layer-by-layer (LbL) self-assembly technique, poly (ethylenimine) (PEI) and poly (acrylic acid) (PAA) multilayer film is deposited on the SDSMF-LPG sensor for both supporting and signal enhancement, and then a glucose oxidase (GOD) layer is immobilized on the outer layer for glucose sensing. A microfluidic chip for glucose detection is fabricated after embedding the SDSMF-LPG biosensor into the microchannel of the chip. Experimental results reveal that the SDSMF-LPG biosensor based on such a hybrid sensing film can ultrasensitively detect glucose concentration as low as 1 nM. After integration into the microfluidic chip, the detection range of the sensor is extended from 2 µM to 10 µM, and the response time is remarkablely shortened from 6 minutes to 70 seconds.

  11. Interfacial nano-biosensing in microfluidic droplets for high-sensitivity detection of low-solubility molecules.

    Science.gov (United States)

    Dou, Maowei; García, José Mireles; Zhan, Sihui; Li, XiuJun

    2016-02-28

    Taking advantage of the properties of the high surface-area-to-volume ratio of microfluidic droplets, we developed an innovative interfacial nanosensing strategy based on aptamer-functionalized graphene oxide nanosensors in microfluidic droplets for the high-sensitivity one-step detection of 17β-estradiol and other low-solubility molecules, with the detection sensitivity improved by about 3 orders of magnitude compared to conventional systems.

  12. A Portable and Power-Free Microfluidic Device for Rapid and Sensitive Lead (Pb2+) Detection

    OpenAIRE

    Lianhui Wang; Shiping Song; Gang Liu; Shijiang He; Chunhui Fan

    2012-01-01

    A portable and power-free microfluidic device was designed for rapid and sensitive detection of lead (Pb2+). 11-mercaptoundecanoic acid (MUA)-functionalized gold nanoparticles (MUA-AuNPs) aggregated in the presence of Pb2+ for the chelation mechanism. When we performed this analysis on a polydimethylsiloxane (PDMS) microfluidic chip, the aggregations deposited onto the surface of chip and formed dark lines along the laminar flows in the zigzag micr...

  13. Pyrolyzed Photoresist Electrodes for Integration in Microfluidic Chips for Transmitter Detection from Biological Cells

    DEFF Research Database (Denmark)

    Larsen, Simon Tylsgaard; Argyraki, Aikaterini; Amato, Letizia

    2013-01-01

    In this study, we show how pyrolyzed photoresist carbon electrodes can be used for amperometric detection of potassium-induced transmitter release from large groups of neuronal PC 12 cells. This opens the way for the use of carbon film electrodes in microfabricated devices for neurochemical drug ...... by the difference in photoresist viscosity. By adding a soft bake step to the fabrication procedure, the flatness of pyrolyzed AZ 5214 electrodes could be improved which would facilitate their integration in microfluidic chip devices....

  14. Nanomaterial based detection and degradation of biological and chemical contaminants in a microfluidic system

    Science.gov (United States)

    Jayamohan, Harikrishnan

    Monitoring and remediation of environmental contaminants (biological and chemical) form the crux of global water resource management. There is an extant need to develop point-of-use, low-power, low-cost tools that can address this problem effectively with minimal environmental impact. Nanotechnology and microfluidics have made enormous advances during the past decade in the area of biosensing and environmental remediation. The "marriage" of these two technologies can effectively address some of the above-mentioned needs. In this dissertation, nanomaterials were used in conjunction with microfluidic techniques to detect and degrade biological and chemical pollutants. In the first project, a point-of-use sensor was developed for detection of trichloroethylene (TCE) from water. A self-organizing nanotubular titanium dioxide (TNA) synthesized by electrochemical anodization and functionalized with photocatalytically deposited platinum (Pt/TNA) was applied to the detection. The morphology and crystallinity of the Pt/TNA sensor was characterized using field emission scanning electron microscope, energy dis- persive x-ray spectroscopy, and X-ray diffraction. The sensor could detect TCE in the concentrations ranging from 10 to 1000 ppm. The room-temperature operation capability of the sensor makes it less power intensive and can potentially be incorporated into a field-based sensor. In the second part, TNA synthesized on a foil was incorporated into a flow-based microfluidic format and applied to degradation of a model pollutant, methylene blue. The system was demonstrated to have enhanced photocatalytic performance at higher flow rates (50-200 muL/min) over the same microfluidic format with TiO2 nanoparticulate (commercial P25) catalyst. The microfluidic format with TNA catalyst was able to achieve 82% fractional conversion of 18 mM methylene blue in comparison to 55% in the case of the TiO2 nanoparticulate layer at a flow rate of 200 L/min. The microfluidic device was

  15. A PDMS-Based Cylindrical Hybrid Lens for Enhanced Fluorescence Detection in Microfluidic Systems

    Directory of Open Access Journals (Sweden)

    Bor-Shyh Lin

    2014-02-01

    Full Text Available Microfluidic systems based on fluorescence detection have been developed and applied for many biological and chemical applications. Because of the tiny amount of sample in the system; the induced fluorescence can be weak. Therefore, most microfluidic systems deploy multiple optical components or sophisticated equipment to enhance the efficiency of fluorescence detection. However, these strategies encounter common issues of complex manufacturing processes and high costs. In this study; a miniature, cylindrical and hybrid lens made of polydimethylsiloxane (PDMS to improve the fluorescence detection in microfluidic systems is proposed. The hybrid lens integrates a laser focusing lens and a fluorescence collecting lens to achieve dual functions and simplify optical setup. Moreover, PDMS has advantages of low-cost and straightforward fabrication compared with conventional optical components. The performance of the proposed lens is first examined with two fluorescent dyes and the results show that the lens provides satisfactory enhancement for fluorescence detection of Rhodamine 6G and Nile Red. The overall increments in collected fluorescence signal and detection sensitivity are more than 220% of those without lens, and the detection limits of Rhodamine 6G and Nile red are lowered to 0.01 μg/mL and 0.05 μg/mL, respectively. The hybrid lens is further applied to the detection of Nile red-labeled Chlorella vulgaris cells and it increases both signal intensity and detection sensitivity by more than 520%. The proposed hybrid lens also dramatically reduces the variation in detected signal caused by the deviation in incident angle of excitation light.

  16. A PDMS-based cylindrical hybrid lens for enhanced fluorescence detection in microfluidic systems.

    Science.gov (United States)

    Lin, Bor-Shyh; Yang, Yu-Ching; Ho, Chong-Yi; Yang, Han-Yu; Wang, Hsiang-Yu

    2014-02-13

    Microfluidic systems based on fluorescence detection have been developed and applied for many biological and chemical applications. Because of the tiny amount of sample in the system; the induced fluorescence can be weak. Therefore, most microfluidic systems deploy multiple optical components or sophisticated equipment to enhance the efficiency of fluorescence detection. However, these strategies encounter common issues of complex manufacturing processes and high costs. In this study; a miniature, cylindrical and hybrid lens made of polydimethylsiloxane (PDMS) to improve the fluorescence detection in microfluidic systems is proposed. The hybrid lens integrates a laser focusing lens and a fluorescence collecting lens to achieve dual functions and simplify optical setup. Moreover, PDMS has advantages of low-cost and straightforward fabrication compared with conventional optical components. The performance of the proposed lens is first examined with two fluorescent dyes and the results show that the lens provides satisfactory enhancement for fluorescence detection of Rhodamine 6G and Nile Red. The overall increments in collected fluorescence signal and detection sensitivity are more than 220% of those without lens, and the detection limits of Rhodamine 6G and Nile red are lowered to 0.01 μg/mL and 0.05 μg/mL, respectively. The hybrid lens is further applied to the detection of Nile red-labeled Chlorella vulgaris cells and it increases both signal intensity and detection sensitivity by more than 520%. The proposed hybrid lens also dramatically reduces the variation in detected signal caused by the deviation in incident angle of excitation light.

  17. PDE Modeling of a Microfluidic Thermal Process for Genetic Analysis Application

    Directory of Open Access Journals (Sweden)

    Reza Banaei Khosroushahi

    2013-01-01

    Full Text Available This paper details the infinite dimensional dynamics of a prototype microfluidic thermal process that is used for genetic analysis purposes. Highly effective infinite dimensional dynamics, in addition to collocated sensor and actuator architecture, require the development of a precise control framework to meet the very tight performance requirements of this system, which are not fully attainable through conventional lumped modeling and controller design approaches. The general partial differential equations describing the dynamics of the system are separated into steady-state and transient parts which are derived for a carefully chosen three-dimensional axisymmetric model. These equations are solved analytically, and the results are verified using an experimentally verified precise finite element method (FEM model. The final combined result is a framework for designing a precise tracking controller applicable to the selected lab-on-a-chip device.

  18. Simultaneous laser-induced fluorescence and contactless-conductivity detection for microfluidic chip

    Institute of Scientific and Technical Information of China (English)

    Feng Shen; Meng Yang; Yong Yu; Qi Kang

    2008-01-01

    A combined detection system involving simultaneous LIF and contactless-conductometric measurements at the same place of the microfluidic chip was described.The LIF measurement was designed according to the confocal principle and a moveable contactless-conductivity detector was used in C4D.Both measurements were mutually independent and advantageous in analyses of mixtures.Various experimental parameters affecting the response were examined and optimized.The performances were demonstrated by simultaneous detection of Rhodamine B.And the results showed that the combined detection system could be used sensitively and reliably.

  19. Chemiluminescence generation and detection in a capillary-driven microfluidic chip

    Science.gov (United States)

    Ramon, Charlotte; Temiz, Yuksel; Delamarche, Emmanuel

    2017-02-01

    The use of microfluidic technology represents a strong opportunity for providing sensitive, low-cost and rapid diagnosis at the point-of-care and such a technology might therefore support better, faster and more efficient diagnosis and treatment of patients at home and in healthcare settings both in developed and developing countries. In this work, we consider luminescence-based assays as an alternative to well-established fluorescence-based systems because luminescence does not require a light source or expensive optical components and is therefore a promising detection method for point-of-care applications. Here, we show a proof-of-concept of chemiluminescence (CL) generation and detection in a capillary-driven microfluidic chip for potential immunoassay applications. We employed a commercial acridan-based reaction, which is catalyzed by horseradish peroxidase (HRP). We investigated CL generation under flow conditions using a simplified immunoassay model where HRP is used instead of the complete sandwich immunocomplex. First, CL signals were generated in a capillary microfluidic chip by immobilizing HRP on a polydimethylsiloxane (PDMS) sealing layer using stencil deposition and flowing CL substrate through the hydrophilic channels. CL signals were detected using a compact (only 5×5×2.5 cm3) and custom-designed scanner, which was assembled for less than $30 and comprised a 128×1 photodiode array, a mini stepper motor, an Arduino microcontroller, and a 3D-printed housing. In addition, microfluidic chips having specific 30-μm-deep structures were fabricated and used to immobilize ensembles of 4.50 μm beads functionalized with HRP so as to generate high CL signals from capillary-driven chips.

  20. Agarose-based microfluidic device for point-of-care concentration and detection of pathogen.

    Science.gov (United States)

    Li, Yiwei; Yan, Xinghua; Feng, Xiaojun; Wang, Jie; Du, Wei; Wang, Yachao; Chen, Peng; Xiong, Liang; Liu, Bi-Feng

    2014-11-04

    Preconcentration of pathogens from patient samples represents a great challenge in point-of-care (POC) diagnostics. Here, a low-cost, rapid, and portable agarose-based microfluidic device was developed to concentrate biological fluid from micro- to picoliter volume. The microfluidic concentrator consisted of a glass slide simply covered by an agarose layer with a binary tree-shaped microchannel, in which pathogens could be concentrated at the end of the microchannel due to the capillary effect and the strong water permeability of the agarose gel. The fluorescent Escherichia coli strain OP50 was used to demonstrate the capacity of the agarose-based device. Results showed that 90% recovery efficiency could be achieved with a million-fold volume reduction from 400 μL to 400 pL. For concentration of 1 × 10(3) cells mL(-1) bacteria, approximately ten million-fold enrichment in cell density was realized with volume reduction from 100 μL to 1.6 pL. Urine and blood plasma samples were further tested to validate the developed method. In conjugation with fluorescence immunoassay, we successfully applied the method to the concentration and detection of infectious Staphylococcus aureus in clinics. The agarose-based microfluidic concentrator provided an efficient approach for POC detection of pathogens.

  1. Immuno-capture and in situ detection of Salmonella typhimurium on a novel microfluidic chip

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Renjie, E-mail: 1058464972@qq.com [College of Chemistry and Chemical Engineering, Chongqing University, No. 174, St. Shazheng, Shapingba District, Chongqing (China); Ni, Yanan, E-mail: 468885029@qq.com [College of Chemistry and Chemical Engineering, Chongqing University, No. 174, St. Shazheng, Shapingba District, Chongqing (China); Xu, Yi, E-mail: xuyibbd@sina.com [College of Chemistry and Chemical Engineering, Chongqing University, No. 174, St. Shazheng, Shapingba District, Chongqing (China); National Center for International Research of Micro/Nano-System and New Material Technology, No. 174, St. Shazhengjie, Shapingba District, Chongqing (China); Key Laboratory of Fundamental Science of Micro/Nano-Device and System Technology for National Defense, Chongqing (China); Jiang, Yan, E-mail: 919865356@qq.com [College of Chemistry and Chemical Engineering, Chongqing University, No. 174, St. Shazheng, Shapingba District, Chongqing (China); Dong, Chunyan, E-mail: 774176325@qq.com [College of Chemistry and Chemical Engineering, Chongqing University, No. 174, St. Shazheng, Shapingba District, Chongqing (China); Chuan, Na, E-mail: 814859441@qq.com [College of Chemistry and Chemical Engineering, Chongqing University, No. 174, St. Shazheng, Shapingba District, Chongqing (China)

    2015-01-01

    Highlights: • A novel microfluidic chip and a LIF microsystem were designed and fabricated. • Salmonella typhimurium was captured and labeled by specific immuno-capture on chip. • CdSe/ZnS quantum dots-labeled bacteria were detected by in situ analysis using LIF microsystem. • The proposed method has potential application in practice. - Abstract: The new method presented in this article achieved the goal of capturing Salmonella typhimurium via immunoreaction and rapid in situ detection of the CdSe/ZnS quantum dots (QDs) labeled S. typhimurium by self-assembly light-emitting diode-induced fluorescence detection (LIF) microsystem on a specially designed multichannel microfluidic chip. CdSe/ZnS QDs were used as fluorescent markers improving detection sensitivity. The microfluidic chip developed in this study was composed of 12 sample channels, 3 mixing zones, and 6 immune reaction zones, which also acted as fluorescence detection zones. QDs–IgG–primary antibody complexes were generated by mixing CdSe/ZnS QDs conjugated secondary antibody (QDs–IgG) and S. typhimurium antibody (primary antibody) in mixing zones. Then, the complexes went into immune reaction zones to label previously captured S. typhimurium in the sandwich mode. The capture rate of S. typhimurium in each detection zone was up to 70%. The enriched QDs-labeled S. typhimurium was detected using a self-assembly LIF microsystem. A good linear relationship was obtained in the range from 3.7 × 10 to 3.7 × 10{sup 5} cfu mL{sup −1} using the equation I = 0.1739 log (C) − 0.1889 with R{sup 2} = 0.9907, and the detection limit was down to 37 cfu mL{sup −1}. The proposed method of online immunolabeling with QDs for in situ fluorescence detection on the designed multichannel microfluidic chip had been successfully used to detect S. typhimurium in pork sample, and it has shown potential advantages in practice.

  2. UV-nanoimprint lithography as a tool to develop flexible microfluidic devices for electrochemical detection.

    Science.gov (United States)

    Chen, Juhong; Zhou, Yiliang; Wang, Danhui; He, Fei; Rotello, Vincent M; Carter, Kenneth R; Watkins, James J; Nugen, Sam R

    2015-07-21

    Research in microfluidic biosensors has led to dramatic improvements in sensitivities. Very few examples of these devices have been commercially successful, keeping this methodology out of the hands of potential users. In this study, we developed a method to fabricate a flexible microfluidic device containing electrowetting valves and electrochemical transduction. The device was designed to be amenable to a roll-to-roll manufacturing system, allowing a low manufacturing cost. Microchannels with high fidelity were structured on a PET film using UV-NanoImprint Lithography (UV-NIL). The electrodes were inkjet-printed and photonically sintered on second flexible PET film. The film containing electrodes was bonded directly to the channel-containing layer to form sealed fluidic device. Actuation of the multivalve system with food dye in PBS buffer was performed to demonstrate automated fluid delivery. The device was then used to detect Salmonella in a liquid sample.

  3. Single nucleotide polymorphism detection using gold nanoprobes and bio-microfluidic platform with embedded microlenses.

    Science.gov (United States)

    Bernacka-Wojcik, Iwona; Águas, Hugo; Carlos, Fabio Ferreira; Lopes, Paulo; Wojcik, Pawel Jerzy; Costa, Mafalda Nascimento; Veigas, Bruno; Igreja, Rui; Fortunato, Elvira; Baptista, Pedro Viana; Martins, Rodrigo

    2015-06-01

    The use of microfluidics platforms combined with the optimal optical properties of gold nanoparticles has found plenty of application in molecular biosensing. This paper describes a bio-microfluidic platform coupled to a non-cross-linking colorimetric gold nanoprobe assay to detect a single nucleotide polymorphism associated with increased risk of obesity fat-mass and obesity-associated (FTO) rs9939609 (Carlos et al., 2014). The system enabled significant discrimination between positive and negative assays using a target DNA concentration of 5 ng/µL below the limit of detection of the conventionally used microplate reader (i.e., 15 ng/µL) with 10 times lower solution volume (i.e., 3 µL). A set of optimization of our previously reported bio-microfluidic platform (Bernacka-Wojcik et al., 2013) resulted in a 160% improvement of colorimetric analysis results. Incorporation of planar microlenses increased 6 times signal-to-loss ratio reaching the output optical fiber improving by 34% the colorimetric analysis of gold nanoparticles, while the implementation of an optoelectronic acquisition system yielded increased accuracy and reduced noise. The microfluidic chip was also integrated with a miniature fiber spectrometer to analyze the assays' colorimetric changes and also the LEDs transmission spectra when illuminating through various solutions. Furthermore, by coupling an optical microscope to a digital camera with a long exposure time (30 s), we could visualise the different scatter intensities of gold nanoparticles within channels following salt addition. These intensities correlate well to the expected difference in aggregation between FTO positive (none to small aggregates) and negative samples (large aggregates).

  4. Gold nanoparticle-based microfluidic sensor for mercury detection

    DEFF Research Database (Denmark)

    Lafleur, Josiane P.; Jensen, Thomas Glasdam; Kutter, Jörg Peter

    2011-01-01

    The contamination of natural resources by human activity can have severe socio-economical impacts. Conventional methods of environmental analysis can be significantly improved by the development of portable microscale technologies for remote/field sensing. A gold nanoparticle-based lab-on-a-chip ......-on-a-chip device was developed for the rapid, in-field detection and quantification of mercury in aquatic environments. Rhodamine 6G functionalized gold nanoparticles allowed the on-chip fluorescence detection of mercury in aqueous samples with a limit of detection of 7 nM....

  5. A microfluidic biosensor using graphene oxide and aptamer-functionalized quantum dots for peanut allergen detection.

    Science.gov (United States)

    Weng, Xuan; Neethirajan, Suresh

    2016-11-15

    The increasing prevalence of food allergies and the intake of packing foods in the past two decades urge the need for more rapid, accurate, and sensitive assays to detect potential allergens in food in order to control the allergen content. Most of the commercial analytical tools for allergen detection rely on immunoassays such as ELISA. As far as disadvantages, ELISA can be time-consuming and expensive. Biosensors appear as a suitable alternative for the detection of allergens because they are rapid, highly sensitive, selective, less expensive, environmentally friendly, and easy to handle. In this study, we developed a microfluidic system integrated with a quantum dots (Qdots) aptamer functionalized graphene oxide (GO) nano-biosensor for simple, rapid, and sensitive food allergen detection. The biosensor utilized Qdots-aptamer-GO complexes as probes to undergo conformational change upon interaction with the food allergens, resulting in fluorescence changes due to the fluorescence quenching and recovering properties of GO by adsorption and desorption of aptamer-conjugated Qdots. This one-step 'turn on' homogenous assay in a ready-to-use microfluidic chip took ~10min to achieve a quantitative detection of Ara h 1, one of the major allergens appearing in peanuts. The results suggested this system had remarkable sensitivity and selectivity. The integration of a microfluidics platform in a homemade miniaturized optical analyzer provides a promising way for the rapid, cost-effective, and accurate on-site determination of food allergens. This biosensor can also be extended to the detection of other food allergens with a selection of corresponding aptamers.

  6. Time encoded multicolor fluorescence detection in a microfluidic flow cytometer.

    Science.gov (United States)

    Martini, Joerg; Recht, Michael I; Huck, Malte; Bern, Marshall W; Johnson, Noble M; Kiesel, Peter

    2012-12-07

    We describe an optical detection technique that delivers high signal-to-noise discrimination to enable a multi-parameter flow cytometer that combines high performance, robustness, compactness and low cost. The enabling technique is termed "spatially modulated detection" and generates a time-dependent signal as a continuously fluorescing (bio-) particle traverses an optical transmission pattern along the fluidic channel. Correlating the detected signal with the expected transmission pattern achieves high discrimination of the particle signal from background noise. Additionally, the particle speed and its fluorescence emission characteristics are deduced from the correlation analysis. Our method uses a large excitation/emission volume along the fluidic channel in order to increase the total flux of fluorescence light that originates from a particle while requiring minimal optical alignment. Despite the large excitation/detection volume, the mask pattern enables a high spatial resolution in the micron range. This allows for detection and characterization of particles with a separation (in flow direction) comparable to the dimension of individual particles. In addition, the concept is intrinsically tolerant of non-encoded background fluorescence originating from fluorescent components in solution, fluorescing components of the chamber and contaminants on its surface. The optical detection technique is illustrated with experimental results of multicolor detection with a single large area detector by filtering fluorescence emission of different particles through a patterned color mask. Thereby the particles' fluorescence emission spectrum is encoded in a time dependent intensity signal and color information can be extracted from the correlation analysis. The multicolor detection technique is demonstrated by differentiation of micro-beads loaded with PE (Phycoerythrin) and PE-Cy5 that are excited at 532 nm.

  7. Automated and miniaturized detection of biological threats with a centrifugal microfluidic system

    Science.gov (United States)

    Mark, D.; van Oordt, T.; Strohmeier, O.; Roth, G.; Drexler, J.; Eberhard, M.; Niedrig, M.; Patel, P.; Zgaga-Griesz, A.; Bessler, W.; Weidmann, M.; Hufert, F.; Zengerle, R.; von Stetten, F.

    2012-06-01

    The world's growing mobility, mass tourism, and the threat of terrorism increase the risk of the fast spread of infectious microorganisms and toxins. Today's procedures for pathogen detection involve complex stationary devices, and are often too time consuming for a rapid and effective response. Therefore a robust and mobile diagnostic system is required. We present a microstructured LabDisk which performs complex biochemical analyses together with a mobile centrifugal microfluidic device which processes the LabDisk. This portable system will allow fully automated and rapid detection of biological threats at the point-of-need.

  8. Integration of programmable microfluidics and on-chip fluorescence detection for biosensing applications

    Science.gov (United States)

    Parks, J. W.; Olson, M. A.; Kim, J.; Ozcelik, D.; Cai, H.; Carrion, R.; Patterson, J. L.; Mathies, R. A.; Hawkins, A. R.; Schmidt, H.

    2014-01-01

    We describe the integration of an actively controlled programmable microfluidic sample processor with on-chip optical fluorescence detection to create a single, hybrid sensor system. An array of lifting gate microvalves (automaton) is fabricated with soft lithography, which is reconfigurably joined to a liquid-core, anti-resonant reflecting optical waveguide (ARROW) silicon chip fabricated with conventional microfabrication. In the automaton, various sample handling steps such as mixing, transporting, splitting, isolating, and storing are achieved rapidly and precisely to detect viral nucleic acid targets, while the optofluidic chip provides single particle detection sensitivity using integrated optics. Specifically, an assay for detection of viral nucleic acid targets is implemented. Labeled target nucleic acids are first captured and isolated on magnetic microbeads in the automaton, followed by optical detection of single beads on the ARROW chip. The combination of automated microfluidic sample preparation and highly sensitive optical detection opens possibilities for portable instruments for point-of-use analysis of minute, low concentration biological samples. PMID:25584111

  9. Integration of programmable microfluidics and on-chip fluorescence detection for biosensing applications.

    Science.gov (United States)

    Parks, J W; Olson, M A; Kim, J; Ozcelik, D; Cai, H; Carrion, R; Patterson, J L; Mathies, R A; Hawkins, A R; Schmidt, H

    2014-09-01

    We describe the integration of an actively controlled programmable microfluidic sample processor with on-chip optical fluorescence detection to create a single, hybrid sensor system. An array of lifting gate microvalves (automaton) is fabricated with soft lithography, which is reconfigurably joined to a liquid-core, anti-resonant reflecting optical waveguide (ARROW) silicon chip fabricated with conventional microfabrication. In the automaton, various sample handling steps such as mixing, transporting, splitting, isolating, and storing are achieved rapidly and precisely to detect viral nucleic acid targets, while the optofluidic chip provides single particle detection sensitivity using integrated optics. Specifically, an assay for detection of viral nucleic acid targets is implemented. Labeled target nucleic acids are first captured and isolated on magnetic microbeads in the automaton, followed by optical detection of single beads on the ARROW chip. The combination of automated microfluidic sample preparation and highly sensitive optical detection opens possibilities for portable instruments for point-of-use analysis of minute, low concentration biological samples.

  10. Gold nanoparticle-based microfluidic sensor for mercury detection

    DEFF Research Database (Denmark)

    Lafleur, Josiane P.; Jensen, Thomas Glasdam; Kutter, Jörg Peter

    2011-01-01

    The contamination of natural resources by human activity can have severe socio-economical impacts. Conventional methods of environmental analysis can be significantly improved by the development of portable microscale technologies for remote/field sensing. A gold nanoparticle-based lab-on-a-chip ......The contamination of natural resources by human activity can have severe socio-economical impacts. Conventional methods of environmental analysis can be significantly improved by the development of portable microscale technologies for remote/field sensing. A gold nanoparticle-based lab......-on-a-chip device was developed for the rapid, in-field detection and quantification of mercury in aquatic environments. Rhodamine 6G functionalized gold nanoparticles allowed the on-chip fluorescence detection of mercury in aqueous samples with a limit of detection of 7 nM....

  11. Fast and sensitive detection of foodborne pathogen using electrochemical impedance analysis, urease catalysis and microfluidics.

    Science.gov (United States)

    Chen, Qi; Wang, Dan; Cai, Gaozhe; Xiong, Yonghua; Li, Yuntao; Wang, Maohua; Huo, Huiling; Lin, Jianhan

    2016-12-15

    Early screening of pathogenic bacteria is a key to prevent and control of foodborne diseases. In this study, we developed a fast and sensitive bacteria detection method integrating electrochemical impedance analysis, urease catalysis with microfluidics and using Listeria as model. The Listeria cells, the anti-Listeria monoclonal antibodies modified magnetic nanoparticles (MNPs), and the anti-Listeria polyclonal antibodies and urease modified gold nanoparticles (AuNPs) were incubated in a fluidic separation chip with active mixing to form the MNP-Listeria-AuNP-urease sandwich complexes. The complexes were captured in the separation chip by applying a high gradient magnetic field, and the urea was injected to resuspend the complexes and hydrolyzed under the catalysis of the urease on the complexes into ammonium ions and carbonate ions, which were transported into a microfluidic detection chip with an interdigitated microelectrode for impedance measurement to determine the amount of the Listeria cells. The capture efficiency of the Listeria cells in the separation chip was ∼93% with a shorter time of 30min due to the faster immuno-reaction using the active magnetic mixing. The changes on both impedance magnitude and phase angle were demonstrated to be able to detect the Listeria cells as low as 1.6×10(2)CFU/mL. The detection time was reduced from original ∼2h to current ∼1h. The recoveries of the spiked lettuce samples ranged from 82.1% to 89.6%, indicating the applicability of this proposed biosensor. This microfluidic impedance biosensor has shown the potential for online, automatic and sensitive bacteria separation and detection.

  12. Love-Wave Sensors Combined with Microfluidics for Fast Detection of Biological Warfare Agents

    Science.gov (United States)

    Matatagui, Daniel; Fontecha, José Luis; Fernández, María Jesús; Gràcia, Isabel; Cané, Carles; Santos, José Pedro; Horrillo, María Carmen

    2014-01-01

    The following paper examines a time-efficient method for detecting biological warfare agents (BWAs). The method is based on a system of a Love-wave immunosensor combined with a microfluidic chip which detects BWA samples in a dynamic mode. In this way a continuous flow-through of the sample is created, promoting the reaction between antigen and antibody and allowing a fast detection of the BWAs. In order to prove this method, static and dynamic modes have been simulated and different concentrations of BWA simulants have been tested with two immunoreactions: phage M13 has been detected using the mouse monoclonal antibody anti-M13 (AM13), and the rabbit immunoglobulin (Rabbit IgG) has been detected using the polyclonal antibody goat anti-rabbit (GAR). Finally, different concentrations of each BWA simulants have been detected with a fast response time and a desirable level of discrimination among them has been achieved. PMID:25029282

  13. Love-Wave Sensors Combined with Microfluidics for Fast Detection of Biological Warfare Agents

    Directory of Open Access Journals (Sweden)

    Daniel Matatagui

    2014-07-01

    Full Text Available The following paper examines a time-efficient method for detecting biological warfare agents (BWAs. The method is based on a system of a Love-wave immunosensor combined with a microfluidic chip which detects BWA samples in a dynamic mode. In this way a continuous flow-through of the sample is created, promoting the reaction between antigen and antibody and allowing a fast detection of the BWAs. In order to prove this method, static and dynamic modes have been simulated and different concentrations of BWA simulants have been tested with two immunoreactions: phage M13 has been detected using the mouse monoclonal antibody anti-M13 (AM13, and the rabbit immunoglobulin (Rabbit IgG has been detected using the polyclonal antibody goat anti-rabbit (GAR. Finally, different concentrations of each BWA simulants have been detected with a fast response time and a desirable level of discrimination among them has been achieved.

  14. Love-wave sensors combined with microfluidics for fast detection of biological warfare agents.

    Science.gov (United States)

    Matatagui, Daniel; Fontecha, José Luis; Fernández, María Jesús; Gràcia, Isabel; Cané, Carles; Santos, José Pedro; Horrillo, María Carmen

    2014-07-15

    The following paper examines a time-efficient method for detecting biological warfare agents (BWAs). The method is based on a system of a Love-wave immunosensor combined with a microfluidic chip which detects BWA samples in a dynamic mode. In this way a continuous flow-through of the sample is created, promoting the reaction between antigen and antibody and allowing a fast detection of the BWAs. In order to prove this method, static and dynamic modes have been simulated and different concentrations of BWA simulants have been tested with two immunoreactions: phage M13 has been detected using the mouse monoclonal antibody anti-M13 (AM13), and the rabbit immunoglobulin (Rabbit IgG) has been detected using the polyclonal antibody goat anti-rabbit (GAR). Finally, different concentrations of each BWA simulants have been detected with a fast response time and a desirable level of discrimination among them has been achieved.

  15. Droplet Microfluidics Platform for Highly Sensitive and Quantitative Detection of Malaria-Causing Plasmodium Parasites Based on Enzyme Activity Measurement

    DEFF Research Database (Denmark)

    Juul, Sissel; Nielsen, Christine Juul Fælled; Labouriau, Rodrigo

    2012-01-01

    detectable at the single-molecule level. Combined with a droplet microfluidics lab-on-a-chip platform, this design allowed for sensitive, specific, and quantitative detection of all human-malaria-causing Plasmodium species in single drops of unprocessed blood with a detection limit of less than one parasite...... detection of even a few parasites is becoming increasingly important for the continued combat against the disease. We believe that the presented droplet microfluidics platform, which has a high potential for adaptation to point-of-care setups suitable for low-resource settings, may contribute significantly...

  16. Centrifugal microfluidic platform for ultrasensitive detection of Botulinum Toxin

    Science.gov (United States)

    Botulinum neurotoxin – a global public health threat and category A bioterrorism agent - is the most toxic substance known and one of the most challenging toxins to detect due to its lethality at extremely low concentrations. Hence the live-mouse bioassay because of its superior sensitivity, remains...

  17. Fast pesticide detection inside microfluidic device with integrated optical pH, oxygen sensors and algal fluorescence.

    Science.gov (United States)

    Tahirbegi, Islam Bogachan; Ehgartner, Josef; Sulzer, Philipp; Zieger, Silvia; Kasjanow, Alice; Paradiso, Mirco; Strobl, Martin; Bouwes, Dominique; Mayr, Torsten

    2017-02-15

    The necessities of developing fast, portable, cheap and easy to handle pesticide detection platforms are getting attention of scientific and industrial communities. Although there are some approaches to develop microchip based pesticide detection platforms, there is no compact microfluidic device for the complementary, fast, cheap, reusable and reliable analysis of different pesticides. In this work, a microfluidic device is developed for in-situ analysis of pesticide concentration detected via metabolism/photosynthesis of Chlamydomonas reinhardtii algal cells (algae) in tap water. Algae are grown in glass based microfluidic chip, which contains integrated optical pH and oxygen sensors in a portable system for on-site detection. In addition, intrinsic algal fluorescence is detected to analyze the pesticide concentration in parallel to pH and oxygen sensors with integrated fluorescence detectors. The response of the algae under the effect of different concentrations of pesticides is evaluated and complementary inhibition effects depending on the pesticide concentration are demonstrated. The three different sensors allow the determination of various pesticide concentrations in the nanomolar concentration range. The miniaturized system provides the fast quantification of pesticides in less than 10min and enables the study of toxic effects of different pesticides on Chlamydomonas reinhardtii green algae. Consequently, the microfluidic device described here provides fast and complementary detection of different pesticides with algae in a novel glass based microfluidic device with integrated optical pH, oxygen sensors and algal fluorescence. Copyright © 2016 Elsevier B.V. All rights reserved.

  18. Direct detection and drug-resistance profiling of bacteremias using inertial microfluidics.

    Science.gov (United States)

    Hou, Han Wei; Bhattacharyya, Roby P; Hung, Deborah T; Han, Jongyoon

    2015-05-21

    Detection of bacteria in bloodstream infections and their antibiotic susceptibility patterns is critical to guide therapeutic decision-making for optimal patient care. Current culture-based assays are too slow (>48 h), leading to excessive up-front use of broad-spectrum antibiotics and/or incorrect antibiotic choices due to resistant bacteria, each with deleterious consequences for patient care and public health. To approach this problem, we describe a method to rapidly isolate bacteria from whole blood using inertial microfluidics and directly determine pathogen identity and antibiotic susceptibility with hybridization-based RNA detection. Using the principle of Dean flow fractionation, bacteria are separated from host blood cells in a label-free separation method with efficient recovery of even low abundance bacteria. Ribosomal RNA detection can then be applied for direct identification of low abundance pathogens (~100 per mL) from blood without culturing or enzymatic amplification. Messenger RNA detection of antibiotic-responsive transcripts after brief drug exposure permits rapid susceptibility determination from bacteria with minimal culturing (~10(5) per mL). This unique coupling of microfluidic cell separation with RNA-based molecular detection techniques represents significant progress towards faster diagnostics (~8 hours) to guide antibiotic therapy.

  19. Rapid detection of tuberculosis using droplet-based microfluidics

    Science.gov (United States)

    Rosenfeld, Liat; Cheng, Yunfeng; Rao, Jianghong; Tang, Sindy K. Y.

    2014-03-01

    Tuberculosis is one of the most deadly diseases that kills over one million people each year and infects one-third of the world's population. The disease is spread by infection with Mycobacterium tuberculosis (Mtb). Owing to its airborne transmission, early diagnosis is critical to the prevention and control of TB. Standard diagnostic methods, acid-fast smear from sputum, often do not become positive until after transmission occurs, which allows the spread of the disease. Culture-based techniques are more sensitive, but take weeks to obtain results because of the extremely slow growth rate of Mtb. In this study a new method to detect indicator enzyme based on the isolation of tubercle bacillus in a large number of picoliter droplets combined with a fluorescent probe has been developed. We use BlaC (an enzyme naturally expressed/secreted by tubercle bacilli) as a marker and a designed BlaC-specific fluorogenic substrates as probes for Mtb detection. We present here a new method to detect the indicator enzyme based on the isolation, digitization and concentration of bacteria samples in a large number of picoliter drops. We show that by controlling the size of the droplets we can control the rate of conversion. Hence rapid increase in signal has been observed as the size of the drops has been decreased. Our vision is that this tool will be able to detect tubercle bacilli in a sensitive, rapid, specific and quantitative manner in vitro at a low cost, particularly in resource limited settings where TB is the most prevalent.

  20. Applicability of confocal Raman microscopy for the signal detective of organic reagents in a PDMS microfluidic chip

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Seung Yeol; Choo, Jae Bum; Ahn, Yoo Min; Kim, Yang S. [Hanyang University, Ansan (Korea, Republic of)

    2002-07-01

    A PDMS microfluidic chip has been constructed using a photolithographic fabrication technique. Confocal laser-induced Raman microscopy has been utilized for the signal detection of chemical species in a PDMS microfluidic chip. The CC1{sub 4} benzene binary mixtures with different % concentrations have been prepared and injected into the PDMS chip using a microsyringe pump. Raman spectra were measured by focusing the Ar{sup +} laser on a microfluidic channel using a 10x objective lens. The concentration of each solvent mixture has been determined from the ratio of Raman intensity profiles, which were measured by integrating the area of characteristic Raman peaks for CC1{sub 4} and benzene. In this work, the feasibility of confocal laser-induced Raman microscopy for the quantitative analysis of organic reagents in a PDMS microfluidic chip will be demonstrated.

  1. Clinical validation of an ultra high-throughput spiral microfluidics for the detection and enrichment of viable circulating tumor cells.

    Directory of Open Access Journals (Sweden)

    Bee Luan Khoo

    Full Text Available Circulating tumor cells (CTCs are cancer cells that can be isolated via liquid biopsy from blood and can be phenotypically and genetically characterized to provide critical information for guiding cancer treatment. Current analysis of CTCs is hindered by the throughput, selectivity and specificity of devices or assays used in CTC detection and isolation.Here, we enriched and characterized putative CTCs from blood samples of patients with both advanced stage metastatic breast and lung cancers using a novel multiplexed spiral microfluidic chip. This system detected putative CTCs under high sensitivity (100%, n = 56 (Breast cancer samples: 12-1275 CTCs/ml; Lung cancer samples: 10-1535 CTCs/ml rapidly from clinically relevant blood volumes (7.5 ml under 5 min. Blood samples were completely separated into plasma, CTCs and PBMCs components and each fraction were characterized with immunophenotyping (Pan-cytokeratin/CD45, CD44/CD24, EpCAM, fluorescence in-situ hybridization (FISH (EML4-ALK or targeted somatic mutation analysis. We used an ultra-sensitive mass spectrometry based system to highlight the presence of an EGFR-activating mutation in both isolated CTCs and plasma cell-free DNA (cf-DNA, and demonstrate concordance with the original tumor-biopsy samples.We have clinically validated our multiplexed microfluidic chip for the ultra high-throughput, low-cost and label-free enrichment of CTCs. Retrieved cells were unlabeled and viable, enabling potential propagation and real-time downstream analysis using next generation sequencing (NGS or proteomic analysis.

  2. Integrated Micro-Optical Fluorescence Detection System for Microfluidic Electrochromatography

    Energy Technology Data Exchange (ETDEWEB)

    ALLERMAN,ANDREW A.; ARNOLD,DON W.; ASBILL,RANDOLPH E.; BAILEY,CHRISTOPHER G.; CARTER,TONY RAY; KEMME,SHANALYN A.; MATZKE,CAROLYN M.; SAMORA,SALLY; SWEATT,WILLIAM C.; WARREN,MIAL E.; WENDT,JOEL R.

    1999-09-16

    The authors describe the design and microfabrication of an extremely compact optical system as a key element in an integrated capillary-channel electrochromatograph with laser induced fluorescence detection. The optical design uses substrate-mode propagation within the fused silica substrate. The optical system includes a vertical cavity surface-emitting laser (VCSEL) array, two high performance microlenses and a commercial photodetector. The microlenses are multilevel diffractive optics patterned by electron beam lithography and etched by reactive ion etching in fused silica. Two generations of optical subsystems are described. The first generation design is integrated directly onto the capillary channel-containing substrate with a 6 mm separation between the VCSEL and photodetector. The second generation design separates the optical system onto its own module and the source to detector length is further compressed to 3.5 mm. The systems are designed for indirect fluorescence detection using infrared dyes. The first generation design has been tested with a 750 nm VCSEL exciting a 10{sup -4} M solution of CY-7 dye. The observed signal-to-noise ratio of better than 100:1 demonstrates that the background signal from scattered pump light is low despite the compact size of the optical system and meets the system sensitivity requirements.

  3. Electrical Impedance Spectroscopy for Detection of Cells in Suspensions Using Microfluidic Device with Integrated Microneedles

    Directory of Open Access Journals (Sweden)

    Muhammad Asraf Mansor

    2017-02-01

    Full Text Available In this study, we introduce novel method of flow cytometry for cell detection based on impedance measurements. The state of the art method for impedance flow cytometry detection utilizes an embedded electrode in the microfluidic to perform measurement of electrical impedance of the presence of cells at the sensing area. Nonetheless, this method requires an expensive and complicated electrode fabrication process. Furthermore, reuse of the fabricated electrode also requires an intensive and tedious cleaning process. Due to that, we present a microfluidic device with integrated microneedles. The two microneedles are placed at the half height of the microchannel for cell detection and electrical measurement. A commercially-available Tungsten needle was utilized for the microneedles. The microneedles are easily removed from the disposable PDMS (Polydimethylsiloxane microchannel and can be reused with a simple cleaning process, such as washing by ultrasonic cleaning. Although this device was low cost, it preserves the core functionality of the sensor, which is capable of detecting passing cells at the sensing area. Therefore, this device is suitable for low-cost medical and food safety screening and testing process in developing countries.

  4. Online coupling of digital microfluidic devices with mass spectrometry detection using an eductor with electrospray ionization.

    Science.gov (United States)

    Baker, Christopher A; Roper, Michael G

    2012-03-20

    MS detection coupled with digital microfluidic (DMF) devices has most commonly been demonstrated in an offline manner using matrix assisted laser desorption ionization. In this work, an eductor is demonstrated which facilitated online coupling of DMF with electrospray ionization MS detection. The eductor consisted of a transfer capillary, a standard ESI needle, and a tapered gas nozzle. As a pulse of N(2) was applied to the nozzle, a pressure differential was induced at the outlet of the ESI needle that pulled droplets from the DMF, past the ESI needle, and into the flow of gas exiting the nozzle, allowing detection by MS. Operating position, ionization potential, and N(2) pressure were optimized, with the optimum ionization potential and N(2) pressure found to be 3206 V and 80 psi, respectively. Online MS detection was demonstrated from both open and closed DMF devices using 2.5 μL and 630 nL aqueous droplets, respectively. Relative quantitation by DMF-MS was demonstrated by mixing droplets of caffeine with droplets of theophylline on an open DMF device and comparing the peak area ratio obtained to an on-chip generated calibration curve. This eductor-based method for transferring droplets has the potential for rapid, versatile, and high-throughput microfluidic analyses.

  5. A Microfluidic Love-Wave Biosensing Device for PSA Detection Based on an Aptamer Beacon Probe.

    Science.gov (United States)

    Zhang, Feng; Li, Shuangming; Cao, Kang; Wang, Pengjuan; Su, Yan; Zhu, Xinhua; Wan, Ying

    2015-06-11

    A label-free and selective aptamer beacon-based Love-wave biosensing device was developed for prostate specific antigen (PSA) detection. The device consists of the following parts: LiTaO3 substrate with SiO2 film as wave guide layer, two set of inter-digital transducers (IDT), gold film for immobilization of the biorecongniton layer and a polydimethylsiloxane (PDMS) microfluidic channels. DNA aptamer, or "artificial antibody", was used as the specific biorecognition probe for PSA capture. Some nucleotides were added to the 3'-end of the aptamer to form a duplex with the 3'-end, turning the aptamer into an aptamer-beacon. Taking advantage of the selective target-induced assembly changes arising from the "aptamer beacon", highly selective and specific detection of PSA was achieved. Furthermore, PDMS microfluidic channels were designed and fabricated to realize automated quantitative sample injection. After optimization of the experimental conditions, the established device showed good performance for PSA detection between 10 ng/mL to 1 μg/mL, with a detection limit of 10 ng/mL. The proposed sensor might be a promising alternative for point of care diagnostics.

  6. A Microfluidic Love-Wave Biosensing Device for PSA Detection Based on an Aptamer Beacon Probe

    Directory of Open Access Journals (Sweden)

    Feng Zhang

    2015-06-01

    Full Text Available A label-free and selective aptamer beacon-based Love-wave biosensing device was developed for prostate specific antigen (PSA detection. The device consists of the following parts: LiTaO3 substrate with SiO2 film as wave guide layer, two set of inter-digital transducers (IDT, gold film for immobilization of the biorecongniton layer and a polydimethylsiloxane (PDMS microfluidic channels. DNA aptamer, or “artificial antibody”, was used as the specific biorecognition probe for PSA capture. Some nucleotides were added to the 3'-end of the aptamer to form a duplex with the 3'-end, turning the aptamer into an aptamer-beacon. Taking advantage of the selective target-induced assembly changes arising from the “aptamer beacon”, highly selective and specific detection of PSA was achieved. Furthermore, PDMS microfluidic channels were designed and fabricated to realize automated quantitative sample injection. After optimization of the experimental conditions, the established device showed good performance for PSA detection between 10 ng/mL to 1 μg/mL, with a detection limit of 10 ng/mL. The proposed sensor might be a promising alternative for point of care diagnostics.

  7. A Review on Microfluidic Paper-Based Analytical Devices for Glucose Detection

    Directory of Open Access Journals (Sweden)

    Shuopeng Liu

    2016-12-01

    Full Text Available Glucose, as an essential substance directly involved in metabolic processes, is closely related to the occurrence of various diseases such as glucose metabolism disorders and islet cell carcinoma. Therefore, it is crucial to develop sensitive, accurate, rapid, and cost effective methods for frequent and convenient detections of glucose. Microfluidic Paper-based Analytical Devices (μPADs not only satisfying the above requirements but also occupying the advantages of portability and minimal sample consumption, have exhibited great potential in the field of glucose detection. This article reviews and summarizes the most recent improvements in glucose detection in two aspects of colorimetric and electrochemical μPADs. The progressive techniques for fabricating channels on μPADs are also emphasized in this article. With the growth of diabetes and other glucose indication diseases in the underdeveloped and developing countries, low-cost and reliably commercial μPADs for glucose detection will be in unprecedentedly demand.

  8. Fluorescence particle detection using microfluidics and planar optoelectronic elements

    Science.gov (United States)

    Kettlitz, Siegfried W.; Moosmann, Carola; Valouch, Sebastian; Lemmer, Uli

    2014-05-01

    Detection of fluorescent particles is an integral part of flow cytometry for analysis of selectively stained cells. Established flow cytometer designs achieve great sensitivity and throughput but require bulky and expensive components which prohibit mass production of small single-use point-of-care devices. The use of a combination of innovative technologies such as roll-to-roll printed microuidics with integrated optoelectronic components such as printed organic light emitting diodes and printed organic photodiodes enables tremendous opportunities in cost reduction, miniaturization and new application areas. In order to harvest these benefits, the optical setup requires a redesign to eliminate the need for lenses, dichroic mirrors and lasers. We investigate the influence of geometric parameters on the performance of a thin planar design which uses a high power LED as planar light source and a PIN-photodiode as planar detector. Due to the lack of focusing optics and inferior optical filters, the device sensitivity is not yet on par with commercial state of the art flow cytometer setups. From noise measurements, electronic and optical considerations we deduce possible pathways of improving the device performance. We identify that the sensitivity is either limited by dark noise for very short apertures or by noise from background light for long apertures. We calculate the corresponding crossover length. For the device design we conclude that a low device thickness, low particle velocity and short aperture length are necessary to obtain optimal sensitivity.

  9. Isothermal Amplification Methods for the Detection of Nucleic Acids in Microfluidic Devices

    Directory of Open Access Journals (Sweden)

    Giuseppe Spoto

    2012-12-01

    Full Text Available Diagnostic tools for biomolecular detection need to fulfill specific requirements in terms of sensitivity, selectivity and high-throughput in order to widen their applicability and to minimize the cost of the assay. The nucleic acid amplification is a key step in DNA detection assays. It contributes to improving the assay sensitivity by enabling the detection of a limited number of target molecules. The use of microfluidic devices to miniaturize amplification protocols reduces the required sample volume and the analysis times and offers new possibilities for the process automation and integration in one single device. The vast majority of miniaturized systems for nucleic acid analysis exploit the polymerase chain reaction (PCR amplification method, which requires repeated cycles of three or two temperature-dependent steps during the amplification of the nucleic acid target sequence. In contrast, low temperature isothermal amplification methods have no need for thermal cycling thus requiring simplified microfluidic device features. Here, the use of miniaturized analysis systems using isothermal amplification reactions for the nucleic acid amplification will be discussed.

  10. Detection of DNAs by Using Dual Packed Polystyrene Bead-Quantum Dots in a Microfluidic Chip.

    Science.gov (United States)

    Le, Ngoc Tam; Kim, Jong Sung

    2015-01-01

    The semiconductor nanocrystals (or quantum dots) have shown peculiar optical and electrical properties due to their exceptionally small size. In recent years, tremendous researches on quantum dots have been carried out. Among them, QDs as sensing media for biological assay have achieved a great progress. Recently we have reported the detection of DNAs by using fluorescence quenching of QDs after DNA hybridization. Several oligonucleotides and human genomic genes could be detected. In this report we used dual packing of polystyrene bead-quantum dots to detect different kinds of DNAs simultaneously. QDs with different emission peaks were used. Carboxylated-CdSe/ZnS QDs (emission: 525, 605 nm) could bind to microbeads of polystyrene/divinyl benzene via EDC/NHS cross-linking reaction. Polystyrene bead-QDs with different colors were packed in the channel of the microfluidic chip. The fluorescence quenching from the QDs by intercalating dye was observed after hybridization of exon 6 and 7 of p53 gene at the weir in the channel of microfluidic chip. The simultaneous fluorescence quenching of the QDs by PI and TOTO-3 were observed.

  11. Microfluidic biosensing device for controlled trapping and detection of magnetic microparticles

    KAUST Repository

    Giouroudi, Ioanna

    2013-05-01

    A magnetic microfluidic device is proposed to transport and trap magnetic microparticles (MPs) to a sensing area. Once the MPs are concentrated in the vicinity of the sensing area, a spin valve type giant magnetoresistance (GMR) sensor is used to detect their presence. The device is used for the detection of biological targets once they are labeled with functionalized MPs. Manipulation of the MPs is achieved by employing a microstructure which consists of planar ringshaped conducting microloops. These microloops are designed to produce high magnetic field gradients which are directly proportional to the force applied to manipulate the MPs. Upon sequential application of current, starting from the outermost loop, MPs are directed to move from the outermost to the innermost loop. The speed with which the MPs move towards the sensing area is controlled by the speed with which current is switched between the loops. On top of the microstructure, a microfluidic channel is fabricated using a standard photolithography technique and a dry film resist layer (Ordyl SY355). Experimental results showed that MPs of different diameters were successfully trapped at the sensing area and detected by the GMR sensor located directly under the innermost square loop. © 2013 IEEE.

  12. Development of a high-throughput microfluidic integrated microarray for the detection of chimeric bioweapons.

    Energy Technology Data Exchange (ETDEWEB)

    Sheppod, Timothy; Satterfield, Brent; Hukari, Kyle W.; West, Jason A. A.; Hux, Gary A.

    2006-10-01

    The advancement of DNA cloning has significantly augmented the potential threat of a focused bioweapon assault, such as a terrorist attack. With current DNA cloning techniques, toxin genes from the most dangerous (but environmentally labile) bacterial or viral organism can now be selected and inserted into robust organism to produce an infinite number of deadly chimeric bioweapons. In order to neutralize such a threat, accurate detection of the expressed toxin genes, rather than classification on strain or genealogical decent of these organisms, is critical. The development of a high-throughput microarray approach will enable the detection of unknowns chimeric bioweapons. The development of a high-throughput microarray approach will enable the detection of unknown bioweapons. We have developed a unique microfluidic approach to capture and concentrate these threat genes (mRNA's) upto a 30 fold concentration. These captured oligonucleotides can then be used to synthesize in situ oligonucleotide copies (cDNA probes) of the captured genes. An integrated microfluidic architecture will enable us to control flows of reagents, perform clean-up steps and finally elute nanoliter volumes of synthesized oligonucleotides probes. The integrated approach has enabled a process where chimeric or conventional bioweapons can rapidly be identified based on their toxic function, rather than being restricted to information that may not identify the critical nature of the threat.

  13. Reagent-free and portable detection of Bacillus anthracis spores using a microfluidic incubator and smartphone microscope

    Energy Technology Data Exchange (ETDEWEB)

    Hutchison, Janine R.; Erikson, Rebecca L.; Sheen, Allison M.; Ozanich, Richard M.; Kelly, Ryan T.

    2015-08-06

    Rapid, cost-effective bacterial detection systems are needed to respond to potential biothreat events. Here we report the use of smartphone-based microscopy in combination with a simple microfluidic incubation device to detect 5000 Bacillus anthracis spores in 3 hours. This field-deployable approach is compatible with real-time PCR for secondary confirmation.

  14. Simply and reliably integrating micro heaters/sensors in a monolithic PCR-CE microfluidic genetic analysis system.

    Science.gov (United States)

    Zhong, Runtao; Pan, Xiaoyan; Jiang, Lei; Dai, Zhongpeng; Qin, Jianhua; Lin, Bingcheng

    2009-04-01

    A novel fabrication process was presented to construct a monolithic integrated PCR-CE microfluidic DNA analysis system as a step toward building a total genetic analysis microsystem. Microfabricated Titanium/Platinum (Ti/Pt) heaters and resistance temperature detectors (RTDs) were integrated on the backside of a bonded glass chip to provide good thermal transfer and precise temperature detection for the drilled PCR-wells. This heater/RTD integration procedure was simple and reliable, and the resulting metal layer can be easily renewed when the Ti/Pt layer was damaged in later use or novel heater/RTD design was desired. A straightforward "RTD-calibration" method was employed to optimize the chip-based thermal cycling conditions. This method was convenient and rapid, comparing with a conventional RTD-calibration/temperature adjustment method. The highest ramping rates of 14 degrees C/s for heating and 5 degrees C/s for cooling in a 3-microL reaction volume allow 30 complete PCR cycles in about 33 min. After effectively passivating the PCR-well surface, successful lambda-phage DNA amplifications were achieved using a two- or three-temperature cycling protocol. The functionality and performance of the integrated microsystem were demonstrated by successful amplification and subsequent on-line separation/sizing of lambda-phage DNA. A rapid assay for Hepatitis B virus, one of the major human pathogens, was performed in less than 45 min, demonstrating that the developed PCR-CE microsystem was capable of performing automatic and high-speed genetic analysis.

  15. Implementation of microfluidic sandwich ELISA for superior detection of plant pathogens.

    Directory of Open Access Journals (Sweden)

    Numrin Thaitrong

    Full Text Available Rapid and economical screening of plant pathogens is a high-priority need in the seed industry. Crop quality control and disease surveillance demand early and accurate detection in addition to robustness, scalability, and cost efficiency typically required for selective breeding and certification programs. Compared to conventional bench-top detection techniques routinely employed, a microfluidic-based approach offers unique benefits to address these needs simultaneously. To our knowledge, this work reports the first attempt to perform microfluidic sandwich ELISA for Acidovorax citrulli (Ac, watermelon silver mottle virus (WSMoV, and melon yellow spot virus (MYSV screening. The immunoassay occurs on the surface of a reaction chamber represented by a microfluidic channel. The capillary force within the microchannel draws a reagent into the reaction chamber as well as facilitates assay incubation. Because the underlying pad automatically absorbs excess fluid, the only operation required is sequential loading of buffers/reagents. Buffer selection, antibody concentrations, and sample loading scheme were optimized for each pathogen. Assay optimization reveals that the 20-folds lower sample volume demanded by the microchannel structure outweighs the 2- to 4-folds higher antibody concentrations required, resulting in overall 5-10 folds of reagent savings. In addition to cutting the assay time by more than 50%, the new platform offers 65% cost savings from less reagent consumption and labor cost. Our study also shows 12.5-, 2-, and 4-fold improvement in assay sensitivity for Ac, WSMoV, and MYSV, respectively. Practical feasibility is demonstrated using 19 real plant samples. Given a standard 96-well plate format, the developed assay is compatible with commercial fluorescent plate readers and readily amendable to robotic liquid handling systems for completely hand-free assay automation.

  16. An integrated microfluidic sensor for real-time detection of RNA in seawater using preserved reagents

    Science.gov (United States)

    Tsaloglou, M.-N.; Loukas, C. M.; Ruano-López, J. M.; Morgan, H.; Mowlem, M. C.

    2012-04-01

    Quantitation of RNA sequences coding either for key metabolic proteins or highly conserved ribosomal subunits can provide insight on cell abundance, speciation and viability. Nucleic sequence-based amplification (NASBA) is an isothermal alternative to traditional nucleic acid amplification methods, such as quantitative PCR. We present here an integrated microfluidic sensor for cell concentration and lysis, RNA extraction/purification and quantitative RNA detection for environmental applications. The portable system uses pre-loaded reagents, stored as a gel on a disposable microfluidic cartridge, which is manufactured using low-cost injection moulding. The NASBA reaction is monitored real-time using a bespoke control unit which includes: an external fluorescence detector, three peristaltic micro-pumps, two heaters and temperature sensors, a battery, seven pin actuated micro-motors (or valve actuators), and an automatic cartridge insertion mechanism. The system has USB connectivity and none of the expensive components require replacing between reactions. Long-term storage of reagents is critically important for any diagnostic tool that will be used in the field, whether for medical or environmental analysis and has not been previously demonstrated for NASBA reagents on-chip. We have shown effective amplification, for as little as 500 cells of the toxic microalga Karenia brevis using reagents which had been preserved as a gel for 45 days. This is the first reported real-time isothermal RNA amplification using with on-chip preservation. Annealing of primers, amplification at 41 °C and real-time fluorescence detection using, also for the first time, an internal control and sequence-specific molecular beacons was all performed on our microfluidic sensor. Our results show excellent promise as a future quantitative tool of in situ phytoplankton analysis and other environmental applications, where long-term reagent storage and low power consumption is essential.

  17. Smart portable electrophoresis instrument based on multipurpose microfluidic chips with electrochemical detection.

    Science.gov (United States)

    Fernández-la-Villa, Ana; Sánchez-Barragán, Dámaso; Pozo-Ayuso, Diego F; Castaño-Álvarez, Mario

    2012-09-01

    A second generation of a battery-powered portable electrophoresis instrument for the use of ME with electrochemical detection was developed. As the first-generation, the main unit of the instrument (150 mm × 165 mm × 95 mm) consists of four-outputs high-voltage power supply (HVPS) with maximum voltage of 3 KV and acquisition system (bipotentiostat) containing 2-channels for dual electrochemical detection. A new reusable microfluidic platform was designed in order to incorporate the microchips with the portable instrument. In this case, the platform is integrated to the main unit of the instrument so that it is not necessary to have any external cable for the interconnection of both parts, making the use of the complete system easier. The new platform contains all the electrical connections for the HVPS and bipotentiostat, as well as fluidic ports for driving the solutions. The microfluidic electrophoresis instrument is controlled by means of a user-friendly interface from a computer. The possibility of wireless connection (Bluetooth®) allows the use of the instrument without any external cable improving the portability. Therefore, the second generation brings a more compact and integrated electrophoresis instrument for "in situ" applications using microfluidic chips in an easy way. The performance of the electrophoresis system was initially evaluated using single- and dual-channel SU-8/Pyrex microchips with different models of integrated electrodes including microelectrodes and interdigitated arrays. The method was tested in different analytical applications such as separation of neurotransmitters, chlorophenols, purine derivatives, vitamins, polyphenolic acids, and flavones.

  18. Microfluidic study of environmental control of genetic competence in Streptococcus mutans

    Science.gov (United States)

    Son, Minjun; Ghoreishilangroudi, Seyedehdelaram; Ahn, Sang-Joon; Burne, Robert; Hagen, Stephen

    2015-03-01

    The bacterial pathogen Streptococcus mutans has the ability to enter a transient state of genetic competence in which it can integrate exogenous DNA. It regulates the competent state in response to several environmental inputs that include two quorum sensing peptides (CSP and XIP) as well as pH and other variables. However the interplay of these variables in regulating the competent state is poorly understood. We are using microfluidics to isolate and control environmental inputs and examine how the competence regulatory circuit responds at the single cell level. Our studies reveal that the pH of the growth environment plays a critical role in determining how cells respond to the quorum sensing signals: The response to both peptides is sharply tuned to a narrow window of near-neutral pH. Within this optimal pH range, a population responds unimodally to a XIP stimulus, and bimodally to CSP; outside this range the response to both signals is suppressed. Because a growing S. mutans culture acidifies its medium, our findings suggest that the passage of the pH through the sensitivity window transiently activates the competence circuit. In this way a sharply tuned environmental response gives S. mutans fine control over the duration of its competent state. This work is supported by the NIH under NIDCR awards R01 DE023339.

  19. Detection of unlabeled particles in the low micrometer size range using light scattering and hydrodynamic 3D focusing in a microfluidic system

    DEFF Research Database (Denmark)

    Zhuang, Guisheng; Jensen, Thomas G.; Kutter, Jörg P.

    2012-01-01

    In this paper, we describe a microfluidic device composed of integrated microoptical elements and a two‐layer microchannel structure for highly sensitive light scattering detection of micro/submicrometer‐sized particles. In the two‐layer microfluidic system, a sample flow stream is first constrai...... of Reynolds numbers (0.5 micrometer size range by light scattering detection....

  20. Microfluidic Paper-Based Sample Concentration Using Ion Concentration Polarization with Smartphone Detection

    Directory of Open Access Journals (Sweden)

    Xue Li

    2016-11-01

    Full Text Available A simple method for microfluidic paper-based sample concentration using ion concentration polarization (ICP with smartphone detection is developed. The concise and low-cost microfluidic paper-based ICP analytical device, which consists of a black backing layer, a nitrocellulose membrane, and two absorbent pads, is fabricated with the simple lamination method which is widely used for lateral flow strips. Sample concentration on the nitrocellulose membrane is monitored in real time by a smartphone whose camera is used to collect the fluorescence images from the ICP device. A custom image processing algorithm running on the smartphone is used to track the concentrated sample and obtain its fluorescence signal intensity for quantitative analysis. Two different methods for Nafion coating are evaluated and their performances are compared. The characteristics of the ICP analytical device especially with intentionally adjusted physical properties are fully evaluated to optimize its performance as well as to extend its potential applications. Experimental results show that significant concentration enhancement with fluorescence dye sample is obtained with the developed ICP device when a fast depletion of fluorescent dye is observed. The platform based on the simply laminated ICP device with smartphone detection is desired for point-of-care testing in settings with poor resources.

  1. Three-Dimensional Clustered Nanostructures for Microfluidic Surface-Enhanced Raman Detection.

    Science.gov (United States)

    Wang, Gang; Li, Kerui; Purcell, Francis J; Zhao, De; Zhang, Wei; He, Zhongyuan; Tan, Shuai; Tang, Zhenguan; Wang, Hongzhi; Reichmanis, Elsa

    2016-09-21

    A materials fabrication concept based on a fluid-construction strategy to create three-dimensional (3D) ZnO@ZnS-Ag active nanostructures at arbitrary position within confined microchannels to form an integrated microfluidic surface-enhanced Raman spectroscopy (SERS) system is presented. The fluid-construction process allowed facile construction of the nanostructured substrates, which were shown to possess a substantial number of integrated hot spots that support SERS activity. Finite-difference time-domain (FDTD) analysis suggested that the 3D clustered geometry facilitated hot spot formation. High sensitivity and good recycle performance were demonstrated using 4-mercaptobenzoic acid (4-MBA) and a mixture of Rhodamine 6G (R6G) and 4-MBA as target organic pollutants to evaluate the SERS microfluidic device performance. The 3D clustered nanostructures were also effective in the detection of a representative nerve agent and biomolecule. The results of this investigation provide a materials and process approach to the fabrication of requisite nanostructures for the online detection of organic pollutants, devices for real-time observation of environmental hazards, and personal-health monitoring.

  2. Label-free high-throughput detection and content sensing of individual droplets in microfluidic systems.

    Science.gov (United States)

    Yesiloz, Gurkan; Boybay, Muhammed Said; Ren, Carolyn L

    2015-10-21

    This study reports a microwave-microfluidics integrated approach capable of performing droplet detection at high-throughput as well as content sensing of individual droplets without chemical or physical intrusion. The sensing system consists of a custom microwave circuitry and a spiral-shaped microwave resonator that is integrated with microfluidic chips where droplets are generated. The microwave circuitry is very cost effective by using off-the-shelf components only. It eliminates the need for bulky benchtop equipment, and provides a compact, rapid and sensitive tool compatible for Lab-on-a-Chip (LOC) platforms. To evaluate the resonator's sensing capability, it was first applied to differentiate between single-phase fluids which are aqueous solutions with different concentrations of glucose and potassium chloride respectively by measuring its reflection coefficient as a function of frequency. The minimum concentration assessed was 0.001 g ml(-1) for potassium chloride and 0.01 g ml(-1) for glucose. In the droplet detection experiments, it is demonstrated that the microwave sensor is able to detect droplets generated at as high throughput as 3.33 kHz. Around two million droplets were counted over a period of ten minutes without any missing. For droplet sensing experiments, pairs of droplets that were encapsulated with biological materials were generated alternatively in a double T-junction configuration and clearly identified by the microwave sensor. The sensed biological materials include fetal bovine serum, penicillin antibiotic mixture, milk (2% mf) and d-(+)-glucose. This system has significant advantages over optical detection methods in terms of its cost, size and compatibility with LOC settings and also presents significant improvements over other electrical-based detection techniques in terms of its sensitivity and throughput.

  3. Micropatterned sensing hydrogels integrated with reconfigurable microfluidics for detecting protease release from cells.

    Science.gov (United States)

    Son, Kyung Jin; Shin, Dong-Sik; Kwa, Timothy; Gao, Yandong; Revzin, Alexander

    2013-12-17

    Matrix metalloproteinases (MMPs) play a central role in the breakdown of the extracellular matrix and are typically upregulated in cancer cells. The goal of the present study is to develop microwells suitable for capture of cells and detection of cell-secreted proteases. Hydrogel microwells comprised of poly(ethylene glycol) (PEG) were photopatterned on glass and modified with ligands to promote cell adhesion. To sense protease release, peptides cleavable by MMP9 were designed to contain a donor/acceptor FRET pair (FITC and DABCYL). These sensing molecules were incorporated into the walls of the hydrogel wells to enable a detection scheme where cells captured within the wells secreted protease molecules which diffused into the gel, cleaved the peptide, and caused a fluorescence signal to come on. By challenging sensing hydrogel microstructures to known concentrations of recombinant MMP9, the limit of detection was determined to be 0.625 nM with a linear range extending to 40 nM. To enhance sensitivity and to limit cross-talk between adjacent sensing sites, microwell arrays containing small groups (∼20 cells/well) of lymphoma cells were integrated into reconfigurable PDMS microfluidic devices. Using this combination of sensing hydrogel microwells and reconfigurable microfluidics, detection of MMP9 release from as few as 11 cells was demonstrated. Smart hydrogel microstructures capable of sequestering small groups of cells and sensing cell function have multiple applications ranging from diagnostics to cell/tissue engineering. Further development of this technology will include single-cell analysis and function-based cell sorting capabilities.

  4. Development of a paper-based carbon nanotube sensing microfluidic device for biological detection.

    Science.gov (United States)

    Yang, Shih-I; Lei, Kin Fong; Tsai, Shiao-Wen; Hsu, Hsiao-Ting

    2013-01-01

    Carbon nanotube (CNT) has been utilized for the biological detection due to its extremely sensitive to biological molecules. A paper-based CNT sensing microfluidic device has been developed for the detection of protein, i.e., biotin-avidin, binding. We have developed a fabrication method that allows controlled deposition of bundled CNTs with well-defined dimensions to form sensors on paper. Then, polydimethyl siloxane (PDMS) was used to pattern the hydrophobic boundary on paper to form the reaction sites. The proposed fabrication method is based on vacuum filtration process with a metal mask covering on a filter paper for the definition of the dimension of sensor. The length, width, and thickness of the CNT-based sensors are readily controlled by the metal mask and the weight of the CNT powder used during the filtration process, respectively. Homogeneous deposition of CNTs with well-defined dimensions can be achieved. The CNT-based sensor on paper has been demonstrated on the detection of the protein binding. Biotin was first immobilized on the CNT's sidewall and avidin suspended solution was applied to the site. The result of the biotin-avidin binding was measured by the resistance change of the sensor, which is a label-free detection method. It showed the CNT is sensitive to the biological molecules and the proposed paper-based CNT sensing device is a possible candidate for point-of-care biosensors. Thus, electrical bio-assays on paper-based microfluidics can be realized to develop low cost, sensitive, and specific diagnostic devices.

  5. Single-pipetting microfluidic assay device for rapid detection of Salmonella from poultry package.

    Science.gov (United States)

    Fronczek, Christopher F; You, David J; Yoon, Jeong-Yeol

    2013-02-15

    A direct, sensitive, near-real-time, handheld optical immunoassay device was developed to detect Salmonella typhimurium in the naturally occurring liquid from fresh poultry packages (hereafter "chicken matrix"), with just single pipetting of sample (i.e., no filtration, culturing and/or isolation, thus reducing the assay time and the error associated with them). Carboxylated, polystyrene microparticles were covalently conjugated with anti-Salmonella, and the immunoagglutination due to the presence of Salmonella was detected by reading the Mie scatter signals from the microfluidic channels using a handheld device. The presence of chicken matrix did not affect the light scatter signal, since the optical parameters (particle size d, wavelength of incident light λ and scatter angle θ) were optimized to minimize the effect of sample matrix (animal tissues and blood proteins, etc.). The sample was loaded into a microfluidic chip that was split into two channels, one pre-loaded with vacuum-dried, antibody-conjugated particles and the other with vacuum-dried, bovine serum albumin-conjugated particles. This eliminated the need for a separate negative control, effectively minimizing chip-to-chip and sample-to-sample variations. Particles and the sample were diffused in-channel through chemical agitation by Tween 80, also vacuum-dried within the microchannels. Sequential mixing of the sample to the reagents under a strict laminar flow condition synergistically improved the reproducibility and linearity of the assay. In addition, dried particles were shown to successfully detect lower Salmonella concentrations for up to 8 weeks. The handheld device contains simplified circuitry eliminating unnecessary adjustment stages, providing a stable signal, thus maximizing sensitivity. Total assay time was 10 min, and the detection limit 10 CFU mL(-1) was observed in all matrices, demonstrating the suitability of this device for field assays.

  6. Development of automated high throughput single molecular microfluidic detection platform for signal transduction analysis

    Science.gov (United States)

    Huang, Po-Jung; Baghbani Kordmahale, Sina; Chou, Chao-Kai; Yamaguchi, Hirohito; Hung, Mien-Chie; Kameoka, Jun

    2016-03-01

    Signal transductions including multiple protein post-translational modifications (PTM), protein-protein interactions (PPI), and protein-nucleic acid interaction (PNI) play critical roles for cell proliferation and differentiation that are directly related to the cancer biology. Traditional methods, like mass spectrometry, immunoprecipitation, fluorescence resonance energy transfer, and fluorescence correlation spectroscopy require a large amount of sample and long processing time. "microchannel for multiple-parameter analysis of proteins in single-complex (mMAPS)"we proposed can reduce the process time and sample volume because this system is composed by microfluidic channels, fluorescence microscopy, and computerized data analysis. In this paper, we will present an automated mMAPS including integrated microfluidic device, automated stage and electrical relay for high-throughput clinical screening. Based on this result, we estimated that this automated detection system will be able to screen approximately 150 patient samples in a 24-hour period, providing a practical application to analyze tissue samples in a clinical setting.

  7. Centrifugal Microfluidic System for Nucleic Acid Amplification and Detection.

    Science.gov (United States)

    Miao, Baogang; Peng, Niancai; Li, Lei; Li, Zheng; Hu, Fei; Zhang, Zengming; Wang, Chaohui

    2015-11-04

    We report here the development of a rapid PCR microfluidic system comprising a double-shaft turntable and centrifugal-based disc that rapidly drives the PCR mixture between chambers set at different temperatures, and the bidirectional flow improved the space utilization of the disc. Three heating resistors and thermistors maintained uniform, specific temperatures for the denaturation, annealing, and extension steps of the PCR. Infrared imaging showed that there was little thermal interference between reaction chambers; the system enabled the cycle number and reaction time of each step to be independently adjusted. To validate the function and efficiency of the centrifugal microfluidic system, a 350-base pair target gene from the hepatitis B virus was amplified and quantitated by fluorescence detection. By optimizing the cycling parameters, the reaction time was reduced to 32 min as compared to 120 min for a commercial PCR machine. DNA samples with concentrations ranging from 10 to 10⁶ copies/mL could be quantitatively analyzed using this system. This centrifugal-based microfluidic platform is a useful system and possesses industrialization potential that can be used for portable diagnostics.

  8. Evaluation of coloured materials in microfluidic flow-cells for chemiluminescence detection.

    Science.gov (United States)

    Spilstead, Kara B; Alexander, Richard; Doeven, Egan H; Haswell, Stephen J; Barnett, Neil W; Francis, Paul S

    2017-05-22

    Recent advances in the construction of chemiluminescence flow-cells has included high precision milling of channels into a range of different polymer materials, in efforts to maximise the transfer of light from the chemical reaction to the photodetector. However, little is known of the extent that the colour of polymer materials will influence this transfer. This may become increasingly important as chemiluminescence detection zones are integrated with other operations within microfluidic devices or micro total analysis systems (μTAS). Herein, we compare microfluidic flow-cells fabricated from five polymer sheets (clear, white, black, red, blue), using two flow-cell designs (spiral and serpentine), two modes of photodetection, and four chemiluminescence reactions that provide a range of different emission colours. The direct transfer of light from the reaction within the white flow-cell channel to the photodetector made only minor contributions (10%-20%) to the measured intensity, with the majority of the measured light first interacting with the polymer material into which the channels were machined. The extent that the emitted light was absorbed or reflected by the coloured polymer materials was dependent on not only the properties of the polymer, but also the spectral distribution of the chemiluminescence. The changes in chemiluminescence intensities from absorption of light by the flow-cell materials can be accompanied by distortion of the spectral distribution. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. Centrifugal Microfluidic System for Nucleic Acid Amplification and Detection

    Directory of Open Access Journals (Sweden)

    Baogang Miao

    2015-11-01

    Full Text Available We report here the development of a rapid PCR microfluidic system comprising a double-shaft turntable and centrifugal-based disc that rapidly drives the PCR mixture between chambers set at different temperatures, and the bidirectional flow improved the space utilization of the disc. Three heating resistors and thermistors maintained uniform, specific temperatures for the denaturation, annealing, and extension steps of the PCR. Infrared imaging showed that there was little thermal interference between reaction chambers; the system enabled the cycle number and reaction time of each step to be independently adjusted. To validate the function and efficiency of the centrifugal microfluidic system, a 350-base pair target gene from the hepatitis B virus was amplified and quantitated by fluorescence detection. By optimizing the cycling parameters, the reaction time was reduced to 32 min as compared to 120 min for a commercial PCR machine. DNA samples with concentrations ranging from 10 to 106 copies/mL could be quantitatively analyzed using this system. This centrifugal-based microfluidic platform is a useful system and possesses industrialization potential that can be used for portable diagnostics.

  10. Design and Development of a Microfluidic Amperometric Immunosensor for the Quantitative Detection of 2,6-dichlorobenzamide (BAM) Herbicide Residue in Ground Water

    DEFF Research Database (Denmark)

    Uthuppu, Basil

    and it is a novel characteristic of the microfluidic device prototype. The microfluidic device was automated using Lego® Mindstorms® servomotors to control its micro pumps and valves. By confirming (amperometrically) the regeneration capability of the optimized immunosurface and generating a standard curve for BAM...... the optimized BAM immunoassay and the electrochemical detection method. A modular approach was adopted for the fabrication of the microfluidic platform in order to make the device simple to integrate, automate and maintain. The microfluidic platform has an in-built micro flow-injection analysis (µFIA) system...

  11. Towards a high-throughput label-free detection system combining localized-surface plasmon resonance and microfluidics.

    Science.gov (United States)

    Zhang, Yi; Tang, Yunfang; Hsieh, Yi-Heui; Hsu, Chuen-Yuan; Xi, Jianzhong; Lin, Kuan-Jiuh; Jiang, Xingyu

    2012-09-07

    This work reports an integrated platform combining localized-surface plasmon resonance (LSPR) and microfluidic chips to carry out multiplexed and label-free protein analysis. We fabricated an optical bench to enable detection using only a laboratory UV-Vis spectrophotometer. This assay not only improves throughput, but also allows quantitative analysis.

  12. Integration of spore-based genetically engineered whole-cell sensing systems into portable centrifugal microfluidic platforms.

    Science.gov (United States)

    Date, Amol; Pasini, Patrizia; Daunert, Sylvia

    2010-09-01

    Bacterial whole-cell biosensing systems provide important information about the bioavailable amount of target analytes. They are characterized by high sensitivity and specificity/selectivity along with rapid response times and amenability to miniaturization as well as high-throughput analysis. Accordingly, they have been employed in various environmental and clinical applications. The use of spore-based sensing systems offers the unique advantage of long-term preservation of the sensing cells by taking advantage of the environmental resistance and ruggedness of bacterial spores. In this work, we have incorporated spore-based whole-cell sensing systems into centrifugal compact disk (CD) microfluidic platforms in order to develop a portable sensing system, which should enable the use of these hardy sensors for fast on-field analysis of compounds of interest. For that, we have employed two spore-based sensing systems for the detection of arsenite and zinc, respectively, and evaluated their analytical performance in the miniaturized microfluidic format. Furthermore, we have tested environmental and clinical samples on the CD microfluidic platforms using the spore-based sensors. Germination of spores and quantitative response to the analyte could be obtained in 2.5-3 h, depending on the sensing system, with detection limits of 1 x 10(-7) M for arsenite and 1 x 10(-6) M for zinc in both serum and fresh water samples. Incorporation of spore-based whole-cell biosensing systems on microfluidic platforms enabled the rapid and sensitive detection of the analytes and is expected to facilitate the on-site use of such sensing systems.

  13. Functionalized poly(ethylene glycol) diacrylate microgels by microfluidics: In situ peptide encapsulation for in serum selective protein detection.

    Science.gov (United States)

    Celetti, Giorgia; Natale, Concetta Di; Causa, Filippo; Battista, Edmondo; Netti, Paolo A

    2016-09-01

    Polymeric microparticles represent a robustly platform for the detection of clinically relevant analytes in biological samples; they can be functionalized encapsulating a multiple types of biologics entities, enhancing their applications as a new class of colloid materials. Microfluidic offers a versatile platform for the synthesis of monodisperse and engineered microparticles. In this work, we report microfluidic synthesis of novel polymeric microparticles endowed with specific peptide due to its superior specificity for target binding in complex media. A peptide sequence was efficiently encapsulated into the polymeric network and protein binding occurred with high affinity (KD 0.1-0.4μM). Fluidic dynamics simulation was performed to optimize the production conditions for monodisperse and stable functionalized microgels. The results demonstrate the easy and fast realization, in a single step, of functionalized monodisperse microgels using droplet-microfluidic technique, and how the inclusion of the peptide within polymeric network improve both the affinity and the specificity of protein capture.

  14. Optical biosensor system with integrated microfluidic sample preparation and TIRF based detection

    Science.gov (United States)

    Gilli, Eduard; Scheicher, Sylvia R.; Suppan, Michael; Pichler, Heinz; Rumpler, Markus; Satzinger, Valentin; Palfinger, Christian; Reil, Frank; Hajnsek, Martin; Köstler, Stefan

    2013-05-01

    There is a steadily growing demand for miniaturized bioanalytical devices allowing for on-site or point-of-care detection of biomolecules or pathogens in applications like diagnostics, food testing, or environmental monitoring. These, so called labs-on-a-chip or micro-total analysis systems (μ-TAS) should ideally enable convenient sample-in - result-out type operation. Therefore, the entire process from sample preparation, metering, reagent incubation, etc. to detection should be performed on a single disposable device (on-chip). In the early days such devices were mainly fabricated using glass or silicon substrates and adapting established fabrication technologies from the electronics and semiconductor industry. More recently, the development focuses on the use of thermoplastic polymers as they allow for low-cost high volume fabrication of disposables. One of the most promising materials for the development of plastic based lab-on-achip systems are cyclic olefin polymers and copolymers (COP/COC) due to their excellent optical properties (high transparency and low autofluorescence) and ease of processing. We present a bioanalytical system for whole blood samples comprising a disposable plastic chip based on TIRF (total internal reflection fluorescence) optical detection. The chips were fabricated by compression moulding of COP and microfluidic channels were structured by hot embossing. These microfluidic structures integrate several sample pretreatment steps. These are the separation of erythrocytes, metering of sample volume using passive valves, and reagent incubation for competitive bioassays. The surface of the following optical detection zone is functionalized with specific capture probes in an array format. The plastic chips comprise dedicated structures for simple and effective coupling of excitation light from low-cost laser diodes. This enables TIRF excitation of fluorescently labeled probes selectively bound to detection spots at the microchannel surface

  15. Flow injection based microfluidic device with carbon nanotube electrode for rapid salbutamol detection.

    Science.gov (United States)

    Karuwan, Chanpen; Wisitsoraat, Anurat; Maturos, Thitima; Phokharatkul, Disayut; Sappat, Assawapong; Jaruwongrungsee, Kata; Lomas, Tanom; Tuantranont, Adisorn

    2009-09-15

    A microfabicated flow injection device has been developed for in-channel electrochemical detection (ECD) of a beta-agonist, namely salbutamol. The microfluidic system consists of PDMS (polydimethylsiloxane) microchannel and electrochemical electrodes formed on glass substrate. The carbon nanotube (CNT) on gold layer as working electrode, silver as reference electrode and platinum as auxiliary electrode were deposited on a glass substrate. Silver, platinum, gold and stainless steel catalyst layers were coated by DC-sputtering. CNTs were then grown on the glass substance by thermal chemical vapor deposition (CVD) with gravity effect and water-assisted etching. 100-microm-deep and 500-microm-wide PDMS microchannels fabricated by SU-8 molding and casting were then bonded on glass substrate by oxygen plasma treatment. Flow injection and ECD of salbutamol was performed with the amperometric detection mode for in-channel detection of salbutamol. The influences of flow rate, injection volume, and detection potential on the response of current signal were optimized. Analytical characteristics, such as sensitivity, repeatability and dynamic range have been evaluated. Fast and highly sensitive detection of salbutamol have been achieved. Thus, the proposed combination of the efficient CNT electrode and miniaturized lab-on-a-chip is a powerful platform for beta-agonists detection.

  16. A high-throughput detection method for invasive fruit fly (Diptera: Tephritidae) species based on microfluidic dynamic array.

    Science.gov (United States)

    Jiang, Fan; Fu, Wei; Clarke, Anthony R; Schutze, Mark Kurt; Susanto, Agus; Zhu, Shuifang; Li, Zhihong

    2016-11-01

    Invasive species can be detrimental to a nation's ecology, economy and human health. Rapid and accurate diagnostics are critical to limit the establishment and spread of exotic organisms. The increasing rate of biological invasions relative to the taxonomic expertise available generates a demand for high-throughput, DNA-based diagnostics methods for identification. We designed species-specific qPCR primer and probe combinations for 27 economically important tephritidae species in six genera (Anastrepha, Bactrocera, Carpomya, Ceratitis, Dacus and Rhagoletis) based on 935 COI DNA barcode haplotypes from 181 fruit fly species publically available in BOLD, and then tested the specificity for each primer pair and probe through qPCR of 35 of those species. We then developed a standardization reaction system for detecting the 27 target species based on a microfluidic dynamic array and also applied the method to identify unknown immature samples from port interceptions and field monitoring. This method led to a specific and simultaneous detection for all 27 species in 7.5 h, using only 0.2 μL of reaction system in each reaction chamber. The approach successfully discriminated among species within complexes that had genetic similarities of up to 98.48%, while it also identified all immature samples consistent with the subsequent results of morphological examination of adults which were reared from larvae of cohorts from the same samples. We present an accurate, rapid and high-throughput innovative approach for detecting fruit flies of quarantine concern. This is a new method which has broad potential to be one of international standards for plant quarantine and invasive species detection. © 2016 John Wiley & Sons Ltd.

  17. A microfluidic laser scattering sensor for label-free detection of waterborne pathogens

    Science.gov (United States)

    Wei, Huang; Yang, Limei; Li, Feng

    2016-10-01

    A microfluidic-based multi-angle laser scattering (MALS) sensor capable of acquiring scattering pattern of single particle is demonstrated. The size and relative refractive index (RI) of polystyrene (PS) microspheres were deduced with accuracies of 60 nm and 0.001 by analyzing the scattering patterns. We measured scattering patterns of waterborne parasites i.e., cryptosporidium parvum (c.parvum) and giardia lamblia (g.lamblia), and some other representative species in 1 L water within 1 hour, and the waterborne parasites were identified with accuracy better than 96% by classification of distinctive scattering patterns with a support-vector-machine (SVM) algorithm. The system provides a promising tool for label-free and rapid detection of waterborne parasites.

  18. Implementation of Microfluidic Chip Electrophoresis for the Detection of B-cell Clonality

    Directory of Open Access Journals (Sweden)

    Vazan M

    2016-04-01

    Full Text Available Introduction: A clonal population of B-cells is defined as those cells arising from the mitotic division of a single somatic cell with the same rearrangement of immunoglobulin genes. This gives rise to DNA markers for each individual lymphoid cell and its progenies and enables us to study clonality in different B-cell malignancies using multiplex polymerase chain reaction - PCR. The BIOMED-2 protocol has been implemented for clonality detection in lymphoproliferative diseases and exploits multiplex PCR reaction, subsequently analyzed by heteroduplex analysis (HDA using polyacrylamide gel electrophoresis (PAGE. With the advent of miniaturization and automation of molecular biology methods, lab-on-chip technologies were developed and replace partially the conventional approaches. We tested device for microfluidic chip, which is used for B-cells clonality analysis, using a PCR reaction for three subregions called frameworks (FR of the immunoglobulin heavy locus (IGH gene.

  19. Urinary micro-RNA biomarker detection using capped gold nanoslit SPR in a microfluidic chip.

    Science.gov (United States)

    Mousavi, Mansoureh Z; Chen, Huai-Yi; Lee, Kuang-Li; Lin, Heng; Chen, Hsi-Hsien; Lin, Yuh-Feng; Wong, Chung-Shun; Li, Hsiao Fen; Wei, Pei-Kuen; Cheng, Ji-Yen

    2015-06-21

    Successful diagnosis and treatment of many diseases depends on the availability of sensitive, reliable and low cost tools for the detection of the biomarkers associated with the diseases. Simple methods that use non-invasive biological samples are especially suitable for the deployment in the clinical environment. In this paper we demonstrate the application of a method that employs a capped gold nanoslit surface plasmon resonance (SPR) sensor and a microfluidic chip for the detection of a urinary nucleic acid biomarker in clinical samples. This method detects low concentrations of the biomarker in a relatively large volume (∼1 mL) of the sample. The method utilizes magnetic nanoparticles (MNPs) for the isolation of target molecules and signal enhancement in conjunction with surface plasmon resonance (SPR) on capped gold nanoslits. The ability of the method to detect urinary miRNA-16-5p in AKI patients was tested and the result was compared with the data obtained with the polymerase chain reaction (PCR). miRNA-16-5p has been found to be a specific and noninvasive biomarker for acute kidney injury (AKI). Our method allows the detection of the biomarker in the urine of AKI patients without amplification and labeling of the target molecules.

  20. Duplex microfluidic SERS detection of pathogen antigens with nanoyeast single-chain variable fragments.

    Science.gov (United States)

    Wang, Yuling; Rauf, Sakandar; Grewal, Yadveer S; Spadafora, Lauren J; Shiddiky, Muhammad J A; Cangelosi, Gerard A; Schlücker, Sebastian; Trau, Matt

    2014-10-07

    Quantitative and accurate detection of multiple biomarkers would allow for the rapid diagnosis and treatment of diseases induced by pathogens. Monoclonal antibodies are standard affinity reagents applied for biomarkers detection; however, their production is expensive and labor-intensive. Herein, we report on newly developed nanoyeast single-chain variable fragments (NYscFv) as an attractive alternative to monoclonal antibodies, which offers the unique advantage of a cost-effective production, stability in solution, and target-specificity. By combination of surface-enhanced Raman scattering (SERS) microspectroscopy using glass-coated, highly purified SERS nanoparticle clusters as labels, with a microfluidic device comprising multiple channels, a robust platform for the sensitive duplex detection of pathogen antigens has been developed. Highly sensitive detection for individual Entamoeba histolytica antigen EHI_115350 (limit of detection = 1 pg/mL, corresponding to 58.8 fM) and EHI_182030 (10 pg/mL, corresponding 453 fM) with high specificity has been achieved, employing the newly developed corresponding NYscFv as probe in combination with SERS microspectroscopy at a single laser excitation wavelength. Our first report on SERS-based immunoassays using the novel NYscFv affinity reagent demonstrates the flexibility of NYscFv fragments as viable alternatives to monoclonal antibodies in a range of bioassay platforms and paves the way for further applications.

  1. Microspot-based ELISA in microfluidics: chemiluminescence and colorimetry detection using integrated thin-film hydrogenated amorphous silicon photodiodes.

    Science.gov (United States)

    Novo, Pedro; Prazeres, Duarte Miguel França; Chu, Virginia; Conde, João Pedro

    2011-12-07

    Microfluidic technology has the potential to decrease the time of analysis and the quantity of sample and reactants required in immunoassays, together with the potential of achieving high sensitivity, multiplexing, and portability. A lab-on-a-chip system was developed and optimized using optical and fluorescence microscopy. Primary antibodies are adsorbed onto the walls of a PDMS-based microchannel via microspotting. This probe antibody is then recognised using secondary FITC or HRP labelled antibodies responsible for providing fluorescence or chemiluminescent and colorimetric signals, respectively. The system incorporated a micron-sized thin-film hydrogenated amorphous silicon photodiode microfabricated on a glass substrate. The primary antibody spots in the PDMS-based microfluidic were precisely aligned with the photodiodes for the direct detection of the antibody-antigen molecular recognition reactions using chemiluminescence and colorimetry. The immunoassay takes ~30 min from assay to the integrated detection. The conditions for probe antibody microspotting and for the flow-through ELISA analysis in the microfluidic format with integrated detection were defined using antibody solutions with concentrations in the nM-μM range. Sequential colorimetric or chemiluminescence detection of specific antibody-antigen molecular recognition was quantitatively detected using the photodiode. Primary antibody surface densities down to 0.182 pmol cm(-2) were detected. Multiplex detection using different microspotted primary antibodies was demonstrated.

  2. Cu2+ Detection with Gold Nanoparticles by Patterning Colorimetric Strips on a Filter Membrane Assembled in a Microfluidic Chip%Cu2+ Detection with Gold Nanoparticles by Patterning Colorimetric Strips on a Filter Membrane Assembled in a Microfluidic Chip

    Institute of Scientific and Technical Information of China (English)

    刘颖昳; 虞洁; 陈雯雯; 刘定斌; 王卓; 蒋兴宇

    2012-01-01

    We have developed a microfluidic chip for colorimetric CH2+ detection. In this chip, it is facile to do colorimet- ric Cu2+ detection based on gold nanoparticles. This method has a dynamic detection range from 0.75 to 50 lamol/L with only 20μL solution including detection reagents and sample. The result can be readout by naked eye and pho-tographed by digital cameras. With the help of image processing software, we could measure the RGB value and calculate the Blue/Red ratio for more accurate quantification. Tap water could be detected in this portable chip.

  3. Microfluidic cantilever detects bacteria and measures their susceptibility to antibiotics in small confined volumes

    Science.gov (United States)

    Etayash, Hashem; Khan, M. F.; Kaur, Kamaljit; Thundat, Thomas

    2016-10-01

    In the fight against drug-resistant bacteria, accurate and high-throughput detection is essential. Here, a bimaterial microcantilever with an embedded microfluidic channel with internal surfaces chemically or physically functionalized with receptors selectively captures the bacteria passing through the channel. Bacterial adsorption inside the cantilever results in changes in the resonance frequency (mass) and cantilever deflection (adsorption stress). The excitation of trapped bacteria using infrared radiation (IR) causes the cantilever to deflect in proportion to the infrared absorption of the bacteria, providing a nanomechanical infrared spectrum for selective identification. We demonstrate the in situ detection and discrimination of Listeria monocytogenes at a concentration of single cell per μl. Trapped Escherichia coli in the microchannel shows a distinct nanomechanical response when exposed to antibiotics. This approach, which combines enrichment with three different modes of detection, can serve as a platform for the development of a portable, high-throughput device for use in the real-time detection of bacteria and their response to antibiotics.

  4. Convenient quantification of methanol concentration detection utilizing an integrated microfluidic chip.

    Science.gov (United States)

    Wang, Yao-Nan; Yang, Ruey-Jen; Ju, Wei-Jhong; Wu, Ming-Chang; Fu, Lung-Ming

    2012-09-01

    A rapid and simple technique is proposed for methanol concentration detection using a PMMA (Polymethyl-Methacrylate) microfluidic chip patterned using a commercially available CO2 laser scriber. In the proposed device, methanol and methanol oxidase (MOX) are injected into a three-dimensional circular chamber and are mixed via a vortex stirring effect. The mixture is heated to prompt the formation of formaldehyde and is flowed into a rectangular chamber, to which fuchsin-sulphurous acid is then added. Finally, the microchip is transferred to a UV spectrophotometer for methanol detection purposes. The experimental results show that a correlation coefficient of R(2) = 0.9940 is obtained when plotting the optical density against the methanol concentration for samples and an accuracy as high as 93.1% are compared with the determined by the high quality gas chromatography with concentrations in the range of 2 ∼ 100 ppm. The methanol concentrations of four commercial red wines are successfully detected using the developed device. Overall, the results show that the proposed device provides a rapid and accurate means of detecting the methanol concentration for a variety of applications in the alcoholic beverage inspection and control field.

  5. Protein-protein interaction analysis in single microfluidic droplets using FRET and fluorescence lifetime detection.

    Science.gov (United States)

    Benz, Christian; Retzbach, Heiko; Nagl, Stefan; Belder, Detlev

    2013-07-21

    Herein, we demonstrate the feasibility of a protein-protein interaction analysis and reaction progress monitoring in microfluidic droplets using FRET and microscopic fluorescence lifetime measurements. The fabrication of microdroplet chips using soft- and photolithographic techniques is demonstrated and the resulting chips reliably generate microdroplets of 630 pL and 6.71 nL at frequencies of 7.9 and 0.75 Hz, respectively. They were used for detection of protein-protein interactions in microdroplets using a model system of Alexa Fluor 488 labelled biotinylated BSA, Alexa Fluor 594 labelled streptavidin and unlabelled chicken egg white avidin. These microchips could be used for quantitative detection of avidin and streptavidin in microdroplets in direct and competitive assay formats with nanomolar detection limits, corresponding to attomole protein amounts. Four droplets were found to be sufficient for analytical determination. Fluorescence intensity ratio and fluorescence lifetime measurements were performed and compared for microdroplet FRET determination. A competitive on-chip binding assay for determination of unlabelled avidin using fluorescence lifetime detection could be performed within 135 s only.

  6. High-performance fluorescence-encoded magnetic microbeads as microfluidic protein chip supports for AFP detection.

    Science.gov (United States)

    Gong, Xiaoqun; Yan, Huan; Yang, Jiumin; Wu, Yudong; Zhang, Jian; Yao, Yingyi; Liu, Ping; Wang, Huiquan; Hu, Zhidong; Chang, Jin

    2016-10-01

    Fluorescence-encoded magnetic microbeads (FEMMs), with the fluorescence encoding ability of quantum dots (QDs) and magnetic enrichment and separation functions of Fe3O4 nanoparticles, have been widely used for multiple biomolecular detection as microfluidic protein chip supports. However, the preparation of FEMMs with long-term fluorescent encoding and immunodetection stability is still a challenge. In this work, we designed a novel high-temperature chemical swelling strategy. The QDs and Fe3O4 nanoparticles were effectively packaged into microbeads via the thermal motion of the polymer chains and the hydrophobic interaction between the nanoparticles and microbeads. The FEMMs obtained a highly uniform fluorescent property and long-term encoding and immunodetection stability and could be quickly magnetically separated and enriched. Then, the QD-encoded magnetic microbeads were applied to alpha fetoprotein (AFP) detection via sandwich immunoreaction. The properties of the encoded microspheres were characterized using a self-designed detecting apparatus, and the target molecular concentration in the sample was also quantified. The results suggested that the high-performance FEMMs have great potential in the field of biomolecular detection.

  7. GMR microfluidic biosensor for low concentration detection of Nanomag-D beads

    Science.gov (United States)

    Devkota, J.; Kokkinis, G.; Jamalieh, M.; Phan, M. H.; Srikanth, H.; Cardoso, S.; Cardoso, F. A.; Giouroudi, I.

    2015-06-01

    This paper presents a novel microfluidic biosensor for in-vitro detection of biomolecules labeled by magnetic biomarkers (Nanomag-D beads) suspended in a static fluid in combination with giant magnetoresistance (GMR) sensors. While previous studies were focused mainly on exploring the MR change for biosensing of bacteria labeled with magnetic microparticles, we show that our biosensor can be used for the detection of much smaller pathogens in the range of a few hundred nanometers e.g., viruses labeled with Nanomag-D beads (MNPs). For the measurements we also used a novel method for signal acquisition and demodulation. Expensive function generators, data acquisition devices and lock-in amplifiers are substituted by a generic PC sound card and an algorithm combining the Fast Fourier Transform (FFT) of the signal with a peak detection routine. This way, costs are drastically reduced, portability is enabled, detection hands-on time is reduced, and sample throughput can be increased using automation and efficient data evaluation with the appropriate software.

  8. Demonstration of submersible high-throughput microfluidic immunosensors for underwater explosives detection.

    Science.gov (United States)

    Adams, André A; Charles, Paul T; Deschamps, Jeffrey R; Kusterbeck, Anne W

    2011-11-15

    Significant security threats posed by highly energetic nitroaromatic compounds in aquatic environments and the demilitarization and pending cleanup of areas previously used for munitions manufacture and storage represent a challenge for less expensive, faster, and more sensitive systems capable of analyzing groundwater and seawater samples for trace levels of explosive materials. Presented here is an inexpensive high throughput microfluidic immunosensor (HTMI) platform intended for the rapid, highly selective quantitation of nitroaromatic compounds in the field. Immunoaffinity and fluorescence detection schemes were implemented in tandem on a novel microfluidic device containing 39 parallel microchannels that were 500 μm tall, 250 μm wide, and 2.54 cm long with covalently tethered antibodies that was engineered for high-throughput high-volume sample processing. The devices were produced via a combination of high precision micromilling and hot embossing. Mass transfer limitations were found in conventional microsystems and were minimized due to higher surface area to volume ratios that exceeded those possessed by conventional microdevices and capillaries. Until now, these assays were limited to maximum total volume flow rates of ~1 mL/min due in part to kinetics and high head pressures of single microchannels. In the design demonstrated here, highly parallelized microchannels afforded up to a 100-fold increase in total volume flow rate while maintaining favorable kinetic constraints for efficient antigen-antibody interaction. The assay employed total volume throughput of up to 6 mL/min while yielding signal-to-noise ratios of >15 in all cases. In addition to samples being processed up to 60 times faster than in conventional displacement-based immunoassays, the current system was capable of quantitating 0.01 ng/mL TNT samples without implementing offline preconcentration, thereby, demonstrating the ability to improve sensitivity by as much as 2 orders of magnitude

  9. Multiplex, Quantitative, Reverse Transcription PCR Detection of Influenza Viruses Using Droplet Microfluidic Technology

    Directory of Open Access Journals (Sweden)

    Ravi Prakash

    2014-12-01

    Full Text Available Quantitative, reverse transcription, polymerase chain reaction (qRT-PCR is facilitated by leveraging droplet microfluidic (DMF system, which due to its precision dispensing and sample handling capabilities at microliter and lower volumes has emerged as a popular method for miniaturization of the PCR platform. This work substantially improves and extends the functional capabilities of our previously demonstrated single qRT-PCR micro-chip, which utilized a combination of electrostatic and electrowetting droplet actuation. In the reported work we illustrate a spatially multiplexed micro-device that is capable of conducting up to eight parallel, real-time PCR reactions per usage, with adjustable control on the PCR thermal cycling parameters (both process time and temperature set-points. This micro-device has been utilized to detect and quantify the presence of two clinically relevant respiratory viruses, Influenza A and Influenza B, in human samples (nasopharyngeal swabs, throat swabs. The device performed accurate detection and quantification of the two respiratory viruses, over several orders of RNA copy counts, in unknown (blind panels of extracted patient samples with acceptably high PCR efficiency (>94%. The multi-stage qRT-PCR assays on eight panel patient samples were accomplished within 35–40 min, with a detection limit for the target Influenza virus RNAs estimated to be less than 10 RNA copies per reaction.

  10. Fabrication of tunable microreactor with enzyme modified magnetic nanoparticles for microfluidic electrochemical detection of glucose.

    Science.gov (United States)

    Sheng, Jin; Zhang, Lei; Lei, Jianping; Ju, Huangxian

    2012-01-04

    A microfluidic device was designed for amperometric determination of glucose by packing enzyme modified magnetic nanoparticles (MNPs) in its microchannel as an enzyme microreactor. Glucose oxidase was covalently attached to the surface of MNPs and localized in the microchannel by the help of an external magnetic field, leading to a tunable packing length. By changing the length of microreactor from 3 to 10mm, the performance for glucose detection was optimized. The optimal linear range to glucose was from 25 μM to 15 mM with a detection limit of 11 μM at a length of 6mm. The inter- and intra-day precisions for determination of 1.0mM glucose were 0.8% and 1.7%, respectively, and the device-to-device reproducibility was 95.6%. The enzyme reactor remained its 81% activity after three-week storage. Due to the advantages of the device and fracture sampling technique, serum samples could be directly sampled through the fracture to achieve baseline separation from ascorbic acid, and proteins in the samples did not interfere with the detection. This work provided a promising way for pretreatment-free determination of glucose with low cost and excellent performance.

  11. Cloud-enabled microscopy and droplet microfluidic platform for specific detection of Escherichia coli in water.

    Directory of Open Access Journals (Sweden)

    Alexander Golberg

    Full Text Available We report an all-in-one platform - ScanDrop - for the rapid and specific capture, detection, and identification of bacteria in drinking water. The ScanDrop platform integrates droplet microfluidics, a portable imaging system, and cloud-based control software and data storage. The cloud-based control software and data storage enables robotic image acquisition, remote image processing, and rapid data sharing. These features form a "cloud" network for water quality monitoring. We have demonstrated the capability of ScanDrop to perform water quality monitoring via the detection of an indicator coliform bacterium, Escherichia coli, in drinking water contaminated with feces. Magnetic beads conjugated with antibodies to E. coli antigen were used to selectively capture and isolate specific bacteria from water samples. The bead-captured bacteria were co-encapsulated in pico-liter droplets with fluorescently-labeled anti-E. coli antibodies, and imaged with an automated custom designed fluorescence microscope. The entire water quality diagnostic process required 8 hours from sample collection to online-accessible results compared with 2-4 days for other currently available standard detection methods.

  12. Detection of Infertility-related Neutralizing Antibodies with a Cell-free Microfluidic Method

    Science.gov (United States)

    Eyer, Klaus; Root, Katharina; Verboket, Pascal E.; Dittrich, Petra S.

    2015-11-01

    The unwanted emergence of neutralizing antibodies (nAbs) against an endogenous or a therapeutic protein can result in deficiency diseases or therapy failure. Here, we developed a cell-free microfluidic method for the sensitive detection and quantification of nAbs in human serum that are associated with infertility. We used cell-derived vesicles containing the luteinizing hormone (LH)/choriogonadotropin receptor (LHHCGR) to detect nAbs against LH. The method exploits the entire cellular signal amplification mechanism, and facilitates the detection of as little as 0.44 nM of LH-nAb (Kd 1.5 nM) in human serum matrix within only 15 minutes. In addition, dose-response curves can be generated in less than 2 hours to evaluate the nAB concentration and dissociation constant. The developed system is devoid of problems associated with cell-based assays and we believe that this simple effect-directed analysis can be used in clinical environments, and is adaptable to other hormones or cytokines and their respective nAbs.

  13. Optimization of Surface-Enhanced Raman Spectroscopy Conditions for Implementation into a Microfluidic Device for Drug Detection.

    Science.gov (United States)

    Kline, Neal D; Tripathi, Ashish; Mirsafavi, Rustin; Pardoe, Ian; Moskovits, Martin; Meinhart, Carl; Guicheteau, Jason A; Christesen, Steven D; Fountain, Augustus W

    2016-11-01

    A microfluidic device is being developed by University of California-Santa Barbara as part of a joint effort with the United States Army to develop a portable, rapid drug detection device. Surface-enhanced Raman spectroscopy (SERS) is used to provide a sensitive, selective detection technique within the microfluidic platform employing metallic nanoparticles as the SERS medium. Using several illicit drugs as analytes, the work presented here describes the efforts of the Edgewood Chemical Biological Center to optimize the microfluidic platform by investigating the role of nanoparticle material, nanoparticle size, excitation wavelength, and capping agents on the performance, and drug concentration detection limits achievable with Ag and Au nanoparticles that will ultimately be incorporated into the final design. This study is particularly important as it lays out a systematic comparison of limits of detection and potential interferences from working with several nanoparticle capping agents-such as tannate, citrate, and borate-which does not seem to have been done previously as the majority of studies only concentrate on citrate as the capping agent. Morphine, cocaine, and methamphetamine were chosen as test analytes for this study and were observed to have limits of detection (LOD) in the range of (1.5-4.7) × 10(-8) M (4.5-13 ng/mL), with the borate capping agent having the best performance.

  14. Detecting lateral genetic material transfer

    CERN Document Server

    Calderón, C; Mireles, V; Miramontes, P

    2012-01-01

    The bioinformatical methods to detect lateral gene transfer events are mainly based on functional coding DNA characteristics. In this paper, we propose the use of DNA traits not depending on protein coding requirements. We introduce several semilocal variables that depend on DNA primary sequence and that reflect thermodynamic as well as physico-chemical magnitudes that are able to tell apart the genome of different organisms. After combining these variables in a neural classificator, we obtain results whose power of resolution go as far as to detect the exchange of genomic material between bacteria that are phylogenetically close.

  15. A Label-Free Microfluidic Biosensor for Activity Detection of Single Microalgae Cells Based on Chlorophyll Fluorescence

    Directory of Open Access Journals (Sweden)

    Junsheng Wang

    2013-11-01

    Full Text Available Detection of living microalgae cells is very important for ballast water treatment and analysis. Chlorophyll fluorescence is an indicator of photosynthetic activity and hence the living status of plant cells. In this paper, we developed a novel microfluidic biosensor system that can quickly and accurately detect the viability of single microalgae cells based on chlorophyll fluorescence. The system is composed of a laser diode as an excitation light source, a photodiode detector, a signal analysis circuit, and a microfluidic chip as a microalgae cell transportation platform. To demonstrate the utility of this system, six different living and dead algae samples (Karenia mikimotoi Hansen, Chlorella vulgaris, Nitzschia closterium, Platymonas subcordiformis, Pyramidomonas delicatula and Dunaliella salina were tested. The developed biosensor can distinguish clearly between the living microalgae cells and the dead microalgae cells. The smallest microalgae cells that can be detected by using this biosensor are 3 μm ones. Even smaller microalgae cells could be detected by increasing the excitation light power. The developed microfluidic biosensor has great potential for in situ ballast water analysis.

  16. Integrated microfluidic system for rapid detection of influenza H1N1 virus using a sandwich-based aptamer assay.

    Science.gov (United States)

    Tseng, Yi-Ting; Wang, Chih-Hung; Chang, Chih-Peng; Lee, Gwo-Bin

    2016-08-15

    The rapid spread of influenza-associated H1N1 viruses has caused serious concern in recent years. Therefore, there is an urgent need for the development of automatic, point-of-care devices for rapid diagnosis of the influenza virus. Conventional approaches suffer from several critical issues; notably, they are time-consuming, labor-intensive, and are characterized by relatively low sensitivity. In this work, we present a new approach for fluorescence-based detection of the influenza A H1N1 virus using a sandwich-based aptamer assay that is automatically performed on an integrated microfluidic system. The entire detection process was shortened to 30min using this chip-based system which is much faster than the conventional viral culture method. The limit of detection was significantly improved to 0.032 hemagglutination unit due to the high affinity and high specificity of the H1N1-specific aptamers. The results showed that the two-aptamer microfluidic system had about 10(3) times higher sensitivity than the conventional serological diagnosis. It was demonstrated that the developed microfluidic system may play as a powerful tool in the detection of the H1N1 virus.

  17. Immunomagnetic separation and rapid detection of bacteria using bioluminescence and microfluidics.

    Science.gov (United States)

    Qiu, Jingmin; Zhou, Yun; Chen, Hui; Lin, Jin-Ming

    2009-08-15

    This paper describes an immunomagnetic separation of target bacterial cells from others by using magnetic bead. The surface of bead was coated with antibodies which can capture specific organism. The binding efficiency of immunomagnetic bead (IMB) capturing target bacterial cells was higher than 98% when the concentrations of target and interferent bacterial cells were at the same level. The concentration of bacteria was determined indirectly by detecting adenosine 5'-triphosphate (ATP) employing bioluminescence (BL) reaction of firefly luciferin-ATP. Benzalkonium chloride (BAC) was used as an ATP extractant from living bacterial cells. We found that BAC could enhance the light emission when the concentration of BAC was less than 5.3 x 10(-2)% (w/v) and the BL intensity reached its maximum at the concentration of BAC was 2.7 x 10(-2)%, which was 10-fold stronger than that without BAC. Based on the principle of the IMB, a microfluidic chip combined with immunofluorescence assay for separating and detecting bacteria simultaneously was also developed. The IMBs were magnetically fixed in the bead-beds of chip channels with a 3-mm diameter of NdFeB permanent magnet. The target bacterial cells can be captured magnetically and observed by a fluorescent microscope.

  18. Scattering detection using a photonic-microfluidic integrated device with on-chip collection capabilities.

    Science.gov (United States)

    Watts, Benjamin R; Zhang, Zhiyi; Xu, Chang Qing; Cao, Xudong; Lin, Min

    2014-02-01

    SU-8-based photonic-microfluidic integrated devices with on-chip beam shaping and collection capabilities were demonstrated in a scattering detection and counting application. Through the proper deployment of the tailored beam geometries via the on-chip excitation optics, excellent CV values were measured for 1, 2, and 5 μm blank beads, 16.4, 11.0, and 12.5%, respectively, coupled with a simple free-space optical detection scheme. The performance of these devices was found dependent on the combination of on-chip, lens-shaped beam geometry and bead size. While very low CVs were obtained when the combination was ideal, a nonideal combination could still result in acceptable CVs for flow cytometry; the reliability was confirmed via devices being able to resolve separate populations of 2.0 and 5.0 μm beads from their mixture with low CV values of 15.9 and 18.5%, respectively. On-chip collection using integrated on-chip optical waveguides was shown to be very reliable in comparison with a free-space collection scheme, yielding a coincident rate of 94.2%. A CV as low as 19.2% was obtained from the on-chip excitation and collection of 5 μm beads when the on-chip lens-shaped beam had a 6.0-μm beam waist.

  19. A Concentration-Controllable Microfluidic Droplet Mixer for Mercury Ion Detection

    Directory of Open Access Journals (Sweden)

    Qian-Fang Meng

    2015-07-01

    Full Text Available A microfluidic droplet mixer is developed for rapid detection of Hg(II ions. Reagent concentration and droplets can be precisely controlled by adjusting the flow rates of different fluid phases. By selecting suitable flow rates of the oil phase, probe phase and sample phase, probe droplets and sample droplets can be matched and merged in pairs and subsequently well-mixed in the poly (dimethylsiloxane (PDMS channels. The fluorescence enhancement probe (Rhodamine B mixed with gold nanoparticles encapsulated in droplets can react with Hg(II ions. The Hg(II ion concentration in the sample droplets is adjusted from about 0 to 1000 nM through fluid regulation to simulate possible various contaminative water samples. The intensity of the emission fluorescence is sensitive to Hg(II ions (increases as the Hg(II ion concentration increases. Through the analysis of the acquired fluorescence images, the concentration of Hg(II ions can be precisely detected. With the advantages of less time, cost consumption and easier manipulations, this device would have a great potential in micro-scale sample assays and real-time chemical reaction studies.

  20. NeuroChip: a microfluidic electrophysiological device for genetic and chemical biology screening of Caenorhabditis elegans adult and larvae.

    Science.gov (United States)

    Hu, Chunxiao; Dillon, James; Kearn, James; Murray, Caitriona; O'Connor, Vincent; Holden-Dye, Lindy; Morgan, Hywel

    2013-01-01

    Genetic and chemical biology screens of C. elegans have been of enormous benefit in providing fundamental insight into neural function and neuroactive drugs. Recently the exploitation of microfluidic devices has added greater power to this experimental approach providing more discrete and higher throughput phenotypic analysis of neural systems. Here we make a significant addition to this repertoire through the design of a semi-automated microfluidic device, NeuroChip, which has been optimised for selecting worms based on the electrophysiological features of the pharyngeal neural network. We demonstrate this device has the capability to sort mutant from wild-type worms based on high definition extracellular electrophysiological recordings. NeuroChip resolves discrete differences in excitatory, inhibitory and neuromodulatory components of the neural network from individual animals. Worms may be fed into the device consecutively from a reservoir and recovered unharmed. It combines microfluidics with integrated electrode recording for sequential trapping, restraining, recording, releasing and recovering of C. elegans. Thus mutant worms may be selected, recovered and propagated enabling mutagenesis screens based on an electrophysiological phenotype. Drugs may be rapidly applied during the recording thus permitting compound screening. For toxicology, this analysis can provide a precise description of sub-lethal effects on neural function. The chamber has been modified to accommodate L2 larval stages showing applicability for small size nematodes including parasitic species which otherwise are not tractable to this experimental approach. We also combine NeuroChip with optogenetics for targeted interrogation of the function of the neural circuit. NeuroChip thus adds a new tool for exploitation of C. elegans and has applications in neurogenetics, drug discovery and neurotoxicology.

  1. NeuroChip: a microfluidic electrophysiological device for genetic and chemical biology screening of Caenorhabditis elegans adult and larvae.

    Directory of Open Access Journals (Sweden)

    Chunxiao Hu

    Full Text Available Genetic and chemical biology screens of C. elegans have been of enormous benefit in providing fundamental insight into neural function and neuroactive drugs. Recently the exploitation of microfluidic devices has added greater power to this experimental approach providing more discrete and higher throughput phenotypic analysis of neural systems. Here we make a significant addition to this repertoire through the design of a semi-automated microfluidic device, NeuroChip, which has been optimised for selecting worms based on the electrophysiological features of the pharyngeal neural network. We demonstrate this device has the capability to sort mutant from wild-type worms based on high definition extracellular electrophysiological recordings. NeuroChip resolves discrete differences in excitatory, inhibitory and neuromodulatory components of the neural network from individual animals. Worms may be fed into the device consecutively from a reservoir and recovered unharmed. It combines microfluidics with integrated electrode recording for sequential trapping, restraining, recording, releasing and recovering of C. elegans. Thus mutant worms may be selected, recovered and propagated enabling mutagenesis screens based on an electrophysiological phenotype. Drugs may be rapidly applied during the recording thus permitting compound screening. For toxicology, this analysis can provide a precise description of sub-lethal effects on neural function. The chamber has been modified to accommodate L2 larval stages showing applicability for small size nematodes including parasitic species which otherwise are not tractable to this experimental approach. We also combine NeuroChip with optogenetics for targeted interrogation of the function of the neural circuit. NeuroChip thus adds a new tool for exploitation of C. elegans and has applications in neurogenetics, drug discovery and neurotoxicology.

  2. Microfluidic Immunoassays Based on Self-Assembled Magnetic Bead Patterns and Time-Resolved Luminescence Detection

    OpenAIRE

    Sivagnanam, Venkataragavalu

    2010-01-01

    Microfluidic bio-assays have emerged as the most privileged solutions and provide the basis for the realization of miniaturized bio-analytical systems and clinical diagnostic devices that are portable, user-friendly and cost-effective (Lab-on-a-chip). Two important steps that are implemented in a microfluidic bio-assay are: (a) the immobilization and/or patterning of target-specific bio-molecules on the surface of a microfluidic channel, for selectively capturing bio-targets like antigens or ...

  3. Integrating Electrochemical Detection with Centrifugal Microfluidics for Real-Time and Fully Automated Sample Testing

    DEFF Research Database (Denmark)

    Andreasen, Sune Zoëga; Kwasny, Dorota; Amato, Letizia

    2015-01-01

    experiments, even when the microfluidic disc is spinning at high velocities. Automated sample handling is achieved by designing a microfluidic system to release analyte sequentially, utilizing on-disc passive valving. In addition, the microfluidic system is designed to trap and keep the liquid sample...... stationary during analysis. In this way it is possible to perform cyclic voltammetry (CV) measurements at varying spin speeds, without altering the electrochemical response. This greatly simplifies the interpretation and quantification of data. Finally, real-time and continuous monitoring of an entire...

  4. Adaptive Genetic Algorithm Model for Intrusion Detection

    Directory of Open Access Journals (Sweden)

    K. S. Anil Kumar

    2012-09-01

    Full Text Available Intrusion detection systems are intelligent systems designed to identify and prevent the misuse of computer networks and systems. Various approaches to Intrusion Detection are currently being used, but they are relatively ineffective. Thus the emerging network security systems need be part of the life system and this ispossible only by embedding knowledge into the network. The Adaptive Genetic Algorithm Model - IDS comprising of K-Means clustering Algorithm, Genetic Algorithm and Neural Network techniques. Thetechnique is tested using multitude of background knowledge sets in DARPA network traffic datasets.

  5. The design of a microfluidic biochip for the rapid, multiplexed detection of foodborne pathogens by surface plasmon resonance imaging

    Science.gov (United States)

    Zordan, Michael D.; Grafton, Meggie M. G.; Park, Kinam; Leary, James F.

    2010-02-01

    The rapid detection of foodborne pathogens is increasingly important due to the rising occurrence of contaminated food supplies. We have previously demonstrated the design of a hybrid optical device that has the capability to perform realtime surface plasmon resonance (SPR) and epi-fluorescence imaging. We now present the design of a microfluidic biochip consisting of a two-dimensional array of functionalized gold spots. The spots on the array have been functionalized with capture peptides that specifically bind E. coli O157:H7 or Salmonella enterica. This array is enclosed by a PDMS microfluidic flow cell. A magnetically pre-concentrated sample is injected into the biochip, and whole pathogens will bind to the capture array. The previously constructed optical device is being used to detect the presence and identity of captured pathogens using SPR imaging. This detection occurs in a label-free manner, and does not require the culture of bacterial samples. Molecular imaging can also be performed using the epi-fluorescence capabilities of the device to determine pathogen state, or to validate the identity of the captured pathogens using fluorescently labeled antibodies. We demonstrate the real-time screening of a sample for the presence of E. coli O157:H7 and Salmonella enterica. Additionally the mechanical properties of the microfluidic flow cell will be assessed. The effect of these properties on pathogen capture will be examined.

  6. Detection of Micrococcus Luteus Biofilm Formation in Microfluidic Environments by pH Measurement Using an Ion-Sensitive Field-Effect Transistor

    Directory of Open Access Journals (Sweden)

    Keiji Naruse

    2013-02-01

    Full Text Available Biofilm formation in microfluidic channels is difficult to detect because sampling volumes are too small for conventional turbidity measurements. To detect biofilm formation, we used an ion-sensitive field-effect transistor (ISFET measurement system to measure pH changes in small volumes of bacterial suspension. Cells of Micrococcus luteus (M. luteus were cultured in polystyrene (PS microtubes and polymethylmethacrylate (PMMA-based microfluidic channels laminated with polyvinylidene chloride. In microtubes, concentrations of bacteria and pH in the suspension were analyzed by measuring turbidity and using an ISFET sensor, respectively. In microfluidic channels containing 20 μL of bacterial suspension, we measured pH changes using the ISFET sensor and monitored biofilm formation using a microscope. We detected acidification and alkalinization phases of M. luteus from the ISFET sensor signals in both microtubes and microfluidic channels. In the alkalinization phase, after 2 day culture, dense biofilm formation was observed at the bottom of the microfluidic channels. In this study, we used an ISFET sensor to detect biofilm formation in clinical and industrial microfluidic environments by detecting alkalinization of the culture medium.

  7. Detection of Micrococcus luteus biofilm formation in microfluidic environments by pH measurement using an ion-sensitive field-effect transistor.

    Science.gov (United States)

    Matsuura, Koji; Asano, Yuka; Yamada, Akira; Naruse, Keiji

    2013-01-01

    Biofilm formation in microfluidic channels is difficult to detect because sampling volumes are too small for conventional turbidity measurements. To detect biofilm formation, we used an ion-sensitive field-effect transistor (ISFET) measurement system to measure pH changes in small volumes of bacterial suspension. Cells of Micrococcus luteus (M. luteus) were cultured in polystyrene (PS) microtubes and polymethylmethacrylate (PMMA)-based microfluidic channels laminated with polyvinylidene chloride. In microtubes, concentrations of bacteria and pH in the suspension were analyzed by measuring turbidity and using an ISFET sensor, respectively. In microfluidic channels containing 20 μL of bacterial suspension, we measured pH changes using the ISFET sensor and monitored biofilm formation using a microscope. We detected acidification and alkalinization phases of M. luteus from the ISFET sensor signals in both microtubes and microfluidic channels. In the alkalinization phase, after 2 day culture, dense biofilm formation was observed at the bottom of the microfluidic channels. In this study, we used an ISFET sensor to detect biofilm formation in clinical and industrial microfluidic environments by detecting alkalinization of the culture medium. 

  8. Implementation of a microfluidic conductivity sensor -- a potential sweat electrolyte sensing system for dehydration detection.

    Science.gov (United States)

    Gengchen Liu; Smith, Kyle; Kaya, Tolga

    2014-01-01

    As dehydration continues to plague performance athletes and soldiers, the need for improved dehydration detection is clear. We propose the use of a conductometric sensor as the foundation of a sweat-sensing patch to address this need. The conductometric sensor evaluates the conductivity of solutions with varying sodium concentrations. A lithographic process was used to fabricate a Polydimethylsiloxane (PDMS) microfluidic channel through which solution was flowed. The ionization of the solution that occurs when a voltage is applied results in an effective resistance across the channel. The measured resistance therefore, reflects the ionization of the solution and the corresponding sodium concentration. The potential application of the conductometric sensor in a sweat-sensing patch requires compatibility with a microcontroller and Bluetooth module. Thus, a circuit interface was created. A voltage divider was utilized to convert the output resistance of the sensor to a voltage that could be input into a microcontroller. An AC voltage signal with a frequency of 10 kHz was used as the source voltage of the voltage divider to minimize the faradaic impedance and the double layer effect of the ionized solution. Tests have revealed that the conductometric is capable of precisely measuring the conductivity of a sodium solution. The conductometric sensor will be applied to a sweat sensing patch through future work involving studying the link between sodium concentration in sweat and an individual's dehydration level, developing a sweat-collection method, and developing a method of consideration for the other ions contained in sweat.

  9. A paper/polymer hybrid microfluidic microplate for rapid quantitative detection of multiple disease biomarkers

    Science.gov (United States)

    Sanjay, Sharma T.; Dou, Maowei; Sun, Jianjun; Li, Xiujun

    2016-07-01

    Enzyme linked immunosorbent assay (ELISA) is one of the most widely used laboratory disease diagnosis methods. However, performing ELISA in low-resource settings is limited by long incubation time, large volumes of precious reagents, and well-equipped laboratories. Herein, we developed a simple, miniaturized paper/PMMA (poly(methyl methacrylate)) hybrid microfluidic microplate for low-cost, high throughput, and point-of-care (POC) infectious disease diagnosis. The novel use of porous paper in flow-through microwells facilitates rapid antibody/antigen immobilization and efficient washing, avoiding complicated surface modifications. The top reagent delivery channels can simply transfer reagents to multiple microwells thus avoiding repeated manual pipetting and costly robots. Results of colorimetric ELISA can be observed within an hour by the naked eye. Quantitative analysis was achieved by calculating the brightness of images scanned by an office scanner. Immunoglobulin G (IgG) and Hepatitis B surface Antigen (HBsAg) were quantitatively analyzed with good reliability in human serum samples. Without using any specialized equipment, the limits of detection of 1.6 ng/mL for IgG and 1.3 ng/mL for HBsAg were achieved, which were comparable to commercial ELISA kits using specialized equipment. We envisage that this simple POC hybrid microplate can have broad applications in various bioassays, especially in resource-limited settings.

  10. Study on Microchannel Design and Burst Frequency Detection for Centrifugal Microfluidic System

    Directory of Open Access Journals (Sweden)

    Yaw-Jen Chang

    2013-01-01

    Full Text Available A centrifugal microfluidic system has been developed in this study, enabling the control and measurement of the burst frequency in order to manipulate the liquid. The radial microfluid chips with different microchannel dimensions were designed for simulation analyses and experimental verifications. The microfluidic flow in the microchannel was analyzed using software CFDRC, providing an accurate result compared with that from experiment. The results show that the design of the overflow microchannel can correctly keep the liquid volume with error as low as 5%. For mercurochrome, the burst frequency has an inverse proportion to the channel width, and the simulation results agree with the experimental results. For oil, however, the experimental and simulation results indicate that the relationship between the burst frequency and channel width is not obvious due to oil properties. Since the simulation approach can provide an accurate prediction of flow behavior in the microchannel, the design of radial microfluid chip and the control of burst frequency can be achieved effectively. A practical application to design the centrifugal microfluidic disc for blood typing test was also carried out in this study. The centrifugal microfluidic system can successfully control the spinning speed to achieve the result of adding reagents in a specific sequence.

  11. Laser-induced heating integrated with a microfluidic platform for real-time DNA replication and detection

    Science.gov (United States)

    Hung, Min-Sheng; Ho, Chia-Chin; Chen, Chih-Pin

    2016-08-01

    This study developed a microfluidic platform for replicating and detecting DNA in real time by integrating a laser and a microfluidic device composed of polydimethylsiloxane. The design of the microchannels consisted of a laser-heating area and a detection area. An infrared laser was used as the heating source for DNA replication, and the laser power was adjusted to heat the solutions directly. In addition, strong biotin-avidin binding was used to capture and detect the replicated products. The biotin on one end was bound to avidin and anchored to the surface of the microchannels, whereas the biotin on the other end was bound to the quantum dots (Qdots). The results showed that the fluorescent intensity of the Qdots bound to the replicated products in the detection area increased with the number of thermal cycles created by the laser. When the number of thermal cycles was ≥10, the fluorescent intensity of the Qdots was directly detectable on the surface of the microchannels. The proposed method is more sensitive than detection methods entailing gel electrophoresis.

  12. Detecting bacteria and Determining Their Susceptibility to Antibiotics by Stochastic Confinement in Nanoliter Droplets using Plug-Based Microfluidics

    Energy Technology Data Exchange (ETDEWEB)

    Boedicker, J.; Li, L; Kline, T; Ismagilov, R

    2008-01-01

    This article describes plug-based microfluidic technology that enables rapid detection and drug susceptibility screening of bacteria in samples, including complex biological matrices, without pre-incubation. Unlike conventional bacterial culture and detection methods, which rely on incubation of a sample to increase the concentration of bacteria to detectable levels, this method confines individual bacteria into droplets nanoliters in volume. When single cells are confined into plugs of small volume such that the loading is less than one bacterium per plug, the detection time is proportional to plug volume. Confinement increases cell density and allows released molecules to accumulate around the cell, eliminating the pre-incubation step and reducing the time required to detect the bacteria. We refer to this approach as stochastic confinement. Using the microfluidic hybrid method, this technology was used to determine the antibiogram - or chart of antibiotic sensitivity - of methicillin-resistant Staphylococcus aureus (MRSA) to many antibiotics in a single experiment and to measure the minimal inhibitory concentration (MIC) of the drug cefoxitin (CFX) against this strain. In addition, this technology was used to distinguish between sensitive and resistant strains of S. aureus in samples of human blood plasma. High-throughput microfluidic techniques combined with single-cell measurements also enable multiple tests to be performed simultaneously on a single sample containing bacteria. This technology may provide a method of rapid and effective patient-specific treatment of bacterial infections and could be extended to a variety of applications that require multiple functional tests of bacterial samples on reduced timescales.

  13. Detecting bacteria and determining their susceptibility to antibiotics by stochastic confinement in nanoliter droplets using plug-based microfluidics.

    Science.gov (United States)

    Boedicker, James Q; Li, Liang; Kline, Timothy R; Ismagilov, Rustem F

    2008-08-01

    This article describes plug-based microfluidic technology that enables rapid detection and drug susceptibility screening of bacteria in samples, including complex biological matrices, without pre-incubation. Unlike conventional bacterial culture and detection methods, which rely on incubation of a sample to increase the concentration of bacteria to detectable levels, this method confines individual bacteria into droplets nanoliters in volume. When single cells are confined into plugs of small volume such that the loading is less than one bacterium per plug, the detection time is proportional to plug volume. Confinement increases cell density and allows released molecules to accumulate around the cell, eliminating the pre-incubation step and reducing the time required to detect the bacteria. We refer to this approach as 'stochastic confinement'. Using the microfluidic hybrid method, this technology was used to determine the antibiogram - or chart of antibiotic sensitivity - of methicillin-resistant Staphylococcus aureus (MRSA) to many antibiotics in a single experiment and to measure the minimal inhibitory concentration (MIC) of the drug cefoxitin (CFX) against this strain. In addition, this technology was used to distinguish between sensitive and resistant strains of S. aureus in samples of human blood plasma. High-throughput microfluidic techniques combined with single-cell measurements also enable multiple tests to be performed simultaneously on a single sample containing bacteria. This technology may provide a method of rapid and effective patient-specific treatment of bacterial infections and could be extended to a variety of applications that require multiple functional tests of bacterial samples on reduced timescales.

  14. Microfluidic Platform versus Conventional Real-time PCR for the Detection of Mycoplasma pneumoniae in Respiratory Specimens

    Science.gov (United States)

    Wulff-Burchfield, Elizabeth; Schell, Wiley A.; Eckhardt, Allen E.; Pollack, Michael G.; Hua, Zhishan; Rouse, Jeremy L.; Pamula, Vamsee K.; Srinivasan, Vijay; Benton, Jonathan L.; Alexander, Barbara D.; Wilfret, David A.; Kraft, Monica; Cairns, Charles; Perfect, John R.; Mitchell, Thomas G.

    2010-01-01

    Rapid, accurate diagnosis of community-acquired pneumonia (CAP) due to Mycoplasma pneumoniae is compromised by low sensitivity of culture and serology. PCR has emerged as a sensitive method to detect M. pneumoniae DNA in clinical specimens. However, conventional real-time PCR is not cost-effective for routine out-patient or implementation. Here, we evaluate a novel microfluidic real-time PCR platform (Advanced Liquid Logic, Inc.) that is rapid, portable, and fully automated. We enrolled patients with CAP and extracted DNA from nasopharyngeal wash (NPW) specimens using a biotinylated capture probe and streptavidin-coupled magnetic beads. Each extract was tested for M. pneumoniae-specific DNA by real-time PCR on both conventional and microfluidic platforms using Taqman probe and primers. Three of 59 (5.0%) NPWs were positive, and agreement between the methods was 98%. The microfluidic platform was equally sensitive but three times faster and offers an inexpensive and convenient diagnostic test for microbial DNA. PMID:20227222

  15. Performance of an in-plane detection cell with integrated waveguides for UV/Vis absorbance measurements on microfluidic separation devices

    DEFF Research Database (Denmark)

    Petersen, Nickolaj Jacob; Mogensen, Klaus Bo; Kutter, Jörg Peter

    2002-01-01

    A microfluidic device with integrated waveguides and a long path length detection cell for UV/Vis absorbance detection is presented. The 750 mum U-cell detection geometry was evaluated in terms of its optical performance as well as its influence on efficiency for electrophoretic separations...

  16. A self-triggered picoinjector in microfluidics

    Science.gov (United States)

    Yang, Yiming; Liu, Songsheng; Jia, Chunping; Mao, Hongju; Jin, Qinghui; Zhao, Jianlong; Zhou, Hongbo

    2016-12-01

    Droplet-based microfluidics has recently emerged as a potential platform for studies of single-cell, directed evolution, and genetic sequencing. In droplet-based microfluidics, adding reagents into drops is one of the most important functions. In this paper, we develop a new self-triggered picoinjector to add controlled volumes of reagent into droplets at kilohertz rates. In the picoinjector, the reagent injecting is triggered by the coming droplet itself, without needing a droplet detection module. Meanwhile, the dosing volume can be precisely controlled. These features make the system more practical and reliable. We expect the new picoinjector will find important applications of droplet-based microfluidics in automated biological assay, directed evolution, enzyme assay, and so on.

  17. Digital microfluidics-enabled single-molecule detection by printing and sealing single magnetic beads in femtoliter droplets.

    Science.gov (United States)

    Witters, Daan; Knez, Karel; Ceyssens, Frederik; Puers, Robert; Lammertyn, Jeroen

    2013-06-07

    Digital microfluidics is introduced as a novel platform with unique advantages for performing single-molecule detection. We demonstrate how superparamagnetic beads, used for capturing single protein molecules, can be printed with unprecedentedly high loading efficiency and single bead resolution on an electrowetting-on-dielectric-based digital microfluidic chip by micropatterning the Teflon-AF surface of the device. By transporting droplets containing suspended superparamagnetic beads over a hydrophilic-in-hydrophobic micropatterned Teflon-AF surface, single beads are trapped inside the hydrophilic microwells due to their selective wettability and tailored dimensions. Digital microfluidics presents the following advantages for printing and sealing magnetic beads for single-molecule detection: (i) droplets containing suspended beads can be transported back and forth over the array of hydrophilic microwells to obtain high loading efficiencies of microwells with single beads, (ii) the use of hydrophilic-in-hydrophobic patterns permits the use of a magnet to speed up the bead transfer process to the wells, while the receding droplet meniscus removes excess beads off the chip surface and thereby shortens the bead patterning time, and (iii) reagents can be transported over the printed beads multiple times, while capillary forces and a magnet hold the printed beads in place. High loading efficiencies (98% with a CV of 0.9%) of single beads in microwells were obtained by transporting droplets of suspended beads over the array 10 times in less than 1 min, which is much higher than previously reported methods (40-60%), while the total surface area needed for performing single-molecule detection can be decreased. The performance of the device was demonstrated by fluorescent detection of the presence of the biotinylated enzyme β-galactosidase on streptavidin-coated beads with a linear dynamic range of 4 orders of magnitude ranging from 10 aM to 90 fM.

  18. Modular microfluidic system fabricated in thermoplastics for the strain-specific detection of bacterial pathogens.

    Science.gov (United States)

    Chen, Yi-Wen; Wang, Hong; Hupert, Mateusz; Witek, Makgorzata; Dharmasiri, Udara; Pingle, Maneesh R; Barany, Francis; Soper, Steven A

    2012-09-21

    The recent outbreaks of a lethal E. coli strain in Germany have aroused renewed interest in developing rapid, specific and accurate systems for detecting and characterizing bacterial pathogens in suspected contaminated food and/or water supplies. To address this need, we have designed, fabricated and tested an integrated modular-based microfluidic system and the accompanying assay for the strain-specific identification of bacterial pathogens. The system can carry out the entire molecular processing pipeline in a single disposable fluidic cartridge and detect single nucleotide variations in selected genes to allow for the identification of the bacterial species, even its strain with high specificity. The unique aspect of this fluidic cartridge is its modular format with task-specific modules interconnected to a fluidic motherboard to permit the selection of the target material. In addition, to minimize the amount of finishing steps for assembling the fluidic cartridge, many of the functional components were produced during the polymer molding step used to create the fluidic network. The operation of the cartridge was provided by electronic, mechanical, optical and hydraulic controls located off-chip and packaged into a small footprint instrument (1 ft(3)). The fluidic cartridge was capable of performing cell enrichment, cell lysis, solid-phase extraction (SPE) of genomic DNA, continuous flow (CF) PCR, CF ligase detection reaction (LDR) and universal DNA array readout. The cartridge was comprised of modules situated on a fluidic motherboard; the motherboard was made from polycarbonate, PC, and used for cell lysis, SPE, CF PCR and CF LDR. The modules were task-specific units and performed universal zip-code array readout or affinity enrichment of the target cells with both made from poly(methylmethacrylate), PMMA. Two genes, uidA and sipB/C, were used to discriminate between E. coli and Salmonella, and evaluated as a model system. Results showed that the fluidic

  19. Modular microfluidic system fabricated in thermoplastics for the strain-specific detection of bacterial pathogens†

    Science.gov (United States)

    Chen, Yi-Wen; Wang, Hong; Hupert, Mateusz; Witek, Makgorzata; Dharmasiri, Udara; Pingle, Maneesh R.; Barany, Francis

    2015-01-01

    The recent outbreaks of a lethal E. coli strain in Germany have aroused renewed interest in developing rapid, specific and accurate systems for detecting and characterizing bacterial pathogens in suspected contaminated food and/or water supplies. To address this need, we have designed, fabricated and tested an integrated modular-based microfluidic system and the accompanying assay for the strain-specific identification of bacterial pathogens. The system can carry out the entire molecular processing pipeline in a single disposable fluidic cartridge and detect single nucleotide variations in selected genes to allow for the identification of the bacterial species, even its strain with high specificity. The unique aspect of this fluidic cartridge is its modular format with task-specific modules interconnected to a fluidic motherboard to permit the selection of the target material. In addition, to minimize the amount of finishing steps for assembling the fluidic cartridge, many of the functional components were produced during the polymer molding step used to create the fluidic network. The operation of the cartridge was provided by electronic, mechanical, optical and hydraulic controls located off-chip and packaged into a small footprint instrument (1 ft3). The fluidic cartridge was capable of performing cell enrichment, cell lysis, solid-phase extraction (SPE) of genomic DNA, continuous flow (CF) PCR, CF ligase detection reaction (LDR) and universal DNA array readout. The cartridge was comprised of modules situated on a fluidic motherboard; the motherboard was made from polycarbonate, PC, and used for cell lysis, SPE, CF PCR and CF LDR. The modules were task-specific units and performed universal zip-code array readout or affinity enrichment of the target cells with both made from poly(methylmethacrylate), PMMA. Two genes, uidA and sipB/C, were used to discriminate between E. coli and Salmonella, and evaluated as a model system. Results showed that the fluidic system

  20. Hydrogel-Framed Nanofiber Matrix Integrated with a Microfluidic Device for Fluorescence Detection of Matrix Metalloproteinases-9.

    Science.gov (United States)

    Han, Sang Won; Koh, Won-Gun

    2016-06-21

    Matrix metalloproteinases (MMPs) play a pivotal role in regulating the composition of the extracellular matrix and have a critical role in vascular disease, cancer progression, and bone disorders. This paper describes the design and fabrication of a microdevice as a new platform for highly sensitive MMP-9 detection. In this sensing platform, fluorescein isocyanate (FITC)-labeled MMP-9 specific peptides were covalently immobilized on an electrospun nanofiber matrix to utilize an enzymatic cleavage strategy. Prior to peptide immobilization, the nanofiber matrix was incorporated into hydrogel micropatterns for easy size control and handling of the nanofiber matrix. The resultant hydrogel-framed nanofiber matrix immobilizing the peptides was inserted into microfluidic devices consisting of reaction chambers and detection zones. The immobilized peptides were reacted with the MMP-9-containing solution in a reaction chamber, which resulted in the cleavage of the FITC-containing peptide fragments and subsequently generated fluorescent flow at the detection zone. As higher concentrations of the MMP-9 solution were introduced or larger peptide-immobilizing nanofiber areas were used, more peptides were cleaved, and a stronger fluorescence signal was observed. Due to the huge surface area of the nanofiber and small dimensions of the microsystem, a faster response time (30 min) and lower detection limit (10 pM) could be achieved in this study. The hydrogel-framed nanofiber matrix is disposable and can be replaced with new ones immobilizing either the same or different biomolecules for various bioassays, while the microfluidic system can be continuously reused.

  1. Magneto-optical detection of magnetic nanobeads in a microfluidic channel

    DEFF Research Database (Denmark)

    Donolato, Marco; Vavassori, Paolo; Hansen, Mikkel Fougt

    2013-01-01

    We report on the measurement of the Browinan relaxation frequency of a magnetic nanobeads suspension in microfluidic system using a novel magneto-optical method. We demonstrate that by lock-in analysis of the signal produced on a photodetector by the light transmitted through the particle...

  2. Single-particle detection of virus simulants under microfluidic flow with two-dimensional photonic crystals (Conference Presentation)

    Science.gov (United States)

    Miller, Benjamin L.; Baker, James E.; Sriram, Rashmi

    2017-05-01

    Because of their compatibility with standard CMOS fabrication, small footprint, and exceptional sensitivity, Two-Dimensional Photonic Crystals (2D PhCs) have been posited as attractive components for the development of real-time integrated photonic virus sensors. While detection of single virus-sized particles by 2D PhCs has been demonstrated, specific recognition of a virus simulant under conditions relevant to sensor use (including aqueous solution and microfluidic flow) has remained an unsolved challenge. This talk will describe the design and testing of a W1 waveguide-coupled 2D PhC in the context of addressing that challenge.

  3. Microfluidic biosensor array with integrated poly(2,7-carbazole)/fullerene-based photodiodes for rapid multiplexed detection of pathogens.

    Science.gov (United States)

    Matos Pires, Nuno Miguel; Dong, Tao

    2013-11-25

    A multiplexed microfluidic biosensor made of poly(methylmethacrylate) (PMMA) was integrated into an array of organic blend heterojunction photodiodes (OPDs) for chemiluminescent detection of pathogens. Waterborne Escherichia coli O157:H7, Campylobacter jejuni and adenovirus were targeted in the PMMA chip, and detection of captured pathogens was conducted by poly(2,7-carbazole)/fullerene OPDs which showed a responsivity over 0.20 A/W at 425 nm. The limits of chemiluminescent detection were 5 × 10(5) cells/mL for E. coli, 1 × 10(5) cells/mL for C. jejuni, and 1 × 10(-8) mg/mL for adenovirus. Parallel analysis for all three analytes in less than 35 min was demonstrated. Further recovery tests illustrated the potential of the integrated biosensor for detecting bacteria in real water samples.

  4. Lab-on-chip microfluidic impedance measurement for laminar flow ratio sensing and differential conductivity difference detection

    Science.gov (United States)

    Kong, Tian Fook; Shen, Xinhui; Marcos, Yang, Chun

    2017-06-01

    We present a microfluidic impedance device for achieving both the flow ratio sensing and the conductivity difference detection between sample stream and reference buffer. By using a flow focusing configuration, with the core flow having a higher conductivity sample than the sheath flow streams, the conductance of the device varies linearly with the flow ratio, with R2 > 0.999. On the other hand, by using deionized (DI)-water sheath flow as a reference, we can detect the difference in conductivity between the buffer of core flow and sheath DI-water with a high detection sensitivity of up to 1 nM of sodium chloride solution. Our study provides a promising approach for on-chip flow mixing characterization and bacteria detection.

  5. Microfluidic Chip-based Nucleic Acid Testing using Gingival Crevicular Fluid as a New Technique for Detecting HIV-1 Infection

    Directory of Open Access Journals (Sweden)

    Alex Willyandre

    2013-05-01

    Full Text Available Transmission of HIV-1 infection by individuals in window period who are tested negative in conventional HIV-1 detection would pose the community with serious problems. Several diagnostic tools require specific labora-tory equipment, perfect timing of diagnosis, antibody to HIV-1, and invasive technique to get sample for examination, until high amount of time to process the sample as well as accessibility of remote areas. Many attempts have been made to solve those problems to come to a new detection technique. This review aims to give information about the current development technique for detection of HIV infection. Microfluidic Chip-based Nucleic Acid Testing is currently introduced for detection of HIV-1 infection. This review also cover the possible usage of gingival crevicular fluid as sample specimen that could be taken noninvasively from the individual.DOI: 10.14693/jdi.v18i2.63

  6. Semi-automated bacterial spore detection system with micro-fluidic chips for aerosol collection, spore treatment and ICAN DNA detection.

    Science.gov (United States)

    Inami, Hisao; Tsuge, Kouichiro; Matsuzawa, Mitsuhiro; Sasaki, Yasuhiko; Togashi, Shigenori; Komano, Asuka; Seto, Yasuo

    2009-07-15

    A semi-automated bacterial spore detection system (BSDS) was developed to detect biological threat agents (e.g., Bacillus anthracis) on-site. The system comprised an aerosol sampler, micro-fluidic chip-A (for spore germination and cell lysis), micro-fluidic chip-B (for extraction and detection of genomic DNA) and an analyzer. An aerosol with bacterial spores was first collected in the collection chamber of chip-A with a velocity of 300 l/min, and the chip-A was taken off from the aerosol sampler and loaded into the analyzer. Reagents packaged in the chip-A were sequentially applied into the chamber. The genomic DNA extract from spore lyzate was manually transferred from chip-A to chip-B and loaded into the analyzer. Genomic DNA in chip-B was first trapped on a glass bead column, washed with various reagents, and eluted to the detection chamber by sequential auto-dispensing. Isothermal and chimeric primer-initiated amplification of nucleic acids (ICAN) with fluorescent measurement was adopted to amplify and detect target DNA. Bacillus subtilis was the stimulant of biological warfare agent in this experiment. Pretreatment conditions were optimized by examining bacterial target DNA recovery in the respective steps (aerosol collection, spore germination, cell lysis, and DNA extraction), by an off-chip experiment using a real-time polymerase chain reaction quantification method. Without the germination step, B. subtilis spores did not demonstrate amplification of target DNA. The detection of 10(4) spores was achieved within 2h throughout the micro-fluidic process.

  7. Integration of agglutination assay for protein detection in microfluidic disc using Blu-ray optical pickup unit and optical fluid scanning

    DEFF Research Database (Denmark)

    Uddin, Rokon; Burger, Robert; Donolato, Marco;

    2015-01-01

    We present a novel strategy for thrombin detection by combining a magnetic bead based agglutination assay and low-cost microfluidic disc. The detection method is based on an optomagnetic readout system implemented using a Blu-ray optical pickup unit (OPU) as main optoelectronic component. The assay...

  8. Integration of agglutination assay for protein detection in microfluidic disc using Blu-ray optical pickup unit and optical fluid scanning

    DEFF Research Database (Denmark)

    Uddin, Rokon; Burger, Robert; Donolato, Marco;

    2015-01-01

    We present a novel strategy for thrombin detection by combining a magnetic bead based agglutination assay and low-cost microfluidic disc. The detection method is based on an optomagnetic readout system implemented using a Blu-ray optical pickup unit (OPU) as main optoelectronic component. The ass...

  9. A novel bisulfite-microfluidic temperature gradient capillary electrophoresis platform for highly sensitive detection of gene promoter methylation.

    Science.gov (United States)

    Zhang, Huidan; Shan, Lianfeng; Wang, Xiaonan; Ma, Qian; Fang, Jin

    2013-04-15

    The hypermethylated tumor suppressor gene promoters are widely recognized as promising markers for cancer screening and ideal targets for cancer therapy, however, a major obstacle in their clinical study is highly sensitive screening. To address this limitation, we developed a novel bisulfite-microfluidic temperature gradient capillary electrophoresis (bisulfite-μTGCE) platform for gene methylation analysis by combining bisulfite treatment and slantwise radiative heating system-based μTGCE. Bisulfite-treated genomic DNA (gDNA) was amplified with universal primers for both methylated and unmethylated sequences, and introduced into glass microfluidic chip to perform electrophorectic separation under a continuous temperature gradient based on the formation of heteroduplexes. Eight CDKN2A promoter model fragments with different number and location of methylation sites were prepared and successfully analyzed according to their electrophoretic peak patterns, with high stability, picoliter-scale sample consumption, and significantly increased detection speed. The bisulfite-μTGCE could detect methylated gDNA with a detection limit of 7.5pg, and could distinguish as low as 0.1% methylation level in CDKN2A in an unmethylated background. Detection of seven colorectal cancer (CRC) cell lines with known and unknown methylation statuses of CDKN2A promoter and 20 tumor tissues derived from CRC patients demonstrated the capability of detecting hypermethylation in real-world samples. The wider adaptation of this platform was further supported by the detection of the CDKN2A and MLH1 promoters' methylation statuses in combination. This highly sensitive, fast, and low-consumption platform for methylation detection shows great potential for future clinical applications.

  10. Segmented continuous-flow multiplex polymerase chain reaction microfluidics for high-throughput and rapid foodborne pathogen detection.

    Science.gov (United States)

    Shu, Bowen; Zhang, Chunsun; Xing, Da

    2014-05-15

    High-throughput and rapid identification of multiple foodborne bacterial pathogens is vital in global public health and food industry. To fulfill this need, we propose a segmented continuous-flow multiplex polymerase chain reaction (SCF-MPCR) on a spiral-channel microfluidic device. The device consists of a disposable polytetrafluoroethylene (PTFE) capillary microchannel coiled on three isothermal blocks. Within the channel, n segmented flow regimes are sequentially generated, and m-plex PCR is individually performed in each regime when each mixture is driven to pass three temperature zones, thus providing a rapid analysis throughput of m×n. To characterize the performance of the microfluidic device, continuous-flow multiplex PCR in a single segmented flow has been evaluated by investigating the effect of key reaction parameters, including annealing temperatures, flow rates, polymerase concentration and amount of input DNA. With the optimized parameters, the genomic DNAs from Salmonella enterica, Listeria monocytogenes, Escherichia coli O157:H7 and Staphylococcus aureus could be amplified simultaneously in 19min, and the limit of detection was low, down to 10(2) copiesμL(-1). As proof of principle, the spiral-channel SCF-MPCR was applied to sequentially amplify four different bacterial pathogens from banana, milk, and sausage, displaying a throughput of 4×3 with no detectable cross-contamination.

  11. Cell manipulation in microfluidics.

    Science.gov (United States)

    Yun, Hoyoung; Kim, Kisoo; Lee, Won Gu

    2013-06-01

    Recent advances in the lab-on-a-chip field in association with nano/microfluidics have been made for new applications and functionalities to the fields of molecular biology, genetic analysis and proteomics, enabling the expansion of the cell biology field. Specifically, microfluidics has provided promising tools for enhancing cell biological research, since it has the ability to precisely control the cellular environment, to easily mimic heterogeneous cellular environment by multiplexing, and to analyze sub-cellular information by high-contents screening assays at the single-cell level. Various cell manipulation techniques in microfluidics have been developed in accordance with specific objectives and applications. In this review, we examine the latest achievements of cell manipulation techniques in microfluidics by categorizing externally applied forces for manipulation: (i) optical, (ii) magnetic, (iii) electrical, (iv) mechanical and (v) other manipulations. We furthermore focus on history where the manipulation techniques originate and also discuss future perspectives with key examples where available.

  12. Nanomaterials meet microfluidics.

    Science.gov (United States)

    Pumera, Martin

    2011-05-28

    Nanomaterials and lab-on-a-chip platforms have undergone enormous development during the past decade. Here, we present an overview of how microfluidics benefited from the use of nanomaterials for the enhanced separation and detection of analytes. We also discuss how nanomaterials benefit from microfluidics in terms of synthesis and in terms of the simulation of environments for nanomotors and nanorobots. In our opinion, the "marriage" of nanomaterials and microfluidics is highly beneficial and is expected to solve vital challenges in related fields.

  13. A Portable Automatic Endpoint Detection System for Amplicons of Loop Mediated Isothermal Amplification on Microfluidic Compact Disk Platform

    Directory of Open Access Journals (Sweden)

    Shah Mukim Uddin

    2015-03-01

    Full Text Available In recent years, many improvements have been made in foodborne pathogen detection methods to reduce the impact of food contamination. Several rapid methods have been developed with biosensor devices to improve the way of performing pathogen detection. This paper presents an automated endpoint detection system for amplicons generated by loop mediated isothermal amplification (LAMP on a microfluidic compact disk platform. The developed detection system utilizes a monochromatic ultraviolet (UV emitter for excitation of fluorescent labeled LAMP amplicons and a color sensor to detect the emitted florescence from target. Then it processes the sensor output and displays the detection results on liquid crystal display (LCD. The sensitivity test has been performed with detection limit up to 2.5 × 10−3 ng/µL with different DNA concentrations of Salmonella bacteria. This system allows a rapid and automatic endpoint detection which could lead to the development of a point-of-care diagnosis device for foodborne pathogens detection in a resource-limited environment.

  14. Visual quantification of Hg on a microfluidic paper-based analytical device using distance-based detection technique

    Science.gov (United States)

    Cai, Longfei; Fang, Yanling; Mo, Yuanhui; Huang, Yongshi; Xu, Chunxiu; Zhang, Zhen; Wang, Maoxian

    2017-08-01

    We presented a distance-based detection method for visual quantification of mercury ions on a microfluidic paper-based analytical device (μPAD). Dithizone in NaOH solution was used as chromogenic reagent and deposited onto paper channel delimited by hydrophobic wax barrier. Reactions happened between mercury ions and dithizone to form an insoluble colored complex, producing colored precipitate on the paper channel. The length of colored precipitate could be readily measured using the printed ruler along each device. The length of precipitate increase linearly with the mercury concentrations, mercury in sample solution could be quantified by measuring the length of the colored precipitate. Being free of any electronic instruments, this method has the advantages of portability, ease of use, low cost and disposability. This presented method was used to detect mercury ions in a synthetic sample, demonstrating its potential in on-site and real time analysis.

  15. A microfluidic-based hybrid SPR/molecular imaging biosensor for the multiplexed detection of foodborne pathogens

    Science.gov (United States)

    Zordan, Michael D.; Grafton, Meggie M. G.; Acharya, Ghanashyam; Reece, Lisa M.; Aronson, Arthur I.; Park, Kinam; Leary, James F.

    2009-02-01

    It is important to screen our food supply for pathogen contaminations. Current methods to screen for bacterial contamination involve using costly reagents such as antibodies or PCR reagents or time-costly growth in cultures. There is need for portable, real-time, multiplex pathogen detection technology that can predict the safety of food where it is produced or distributed. Surface plasmon resonance (SPR) imaging is a sensitive, label-free method that can detect the binding of an analyte to a surface due to changes in refractive index that occur upon binding. It can be used for label-free detection of the presence of potential pathogens. Simultaneous fluorescence molecular imaging on the other side of the biochip can be used to ascertain pathogen status or functional state which may affect its potential danger to humans or animals. We are designing and testing hybrid microfluidic biochips to detect multiple pathogens using a combination of SPRI and fluorescence imaging. The device consists of an array of gold spots, each functionalized with a peptide targeting a specific pathogen. This peptide biosensor array is enclosed by a PDMS microfluidic flow chamber that delivers a magnetically concentrated sample to be tested. An SPR image is taken from the bottom of the biochip. Image analysis is used to quantify the amount of pathogen (both live and dead) bound to each spot. Since PDMS is very transmissive to visible light, an epi-fluorescence image is taken from the top of the biochip. Fluorescence imaging determines the live:dead ratio of each pathogen using an inexpensive SYTO 9(R)-Propidium Iodide assay. The volume of sample that the biochip can analyze is small, so possible pathogens are pre-concentrated using immunomagnetic separation. Functionalized magnetic particles are bound to pathogens present in the sample, and a magnet is used to separate them from the bulk fluid.

  16. Nanowell surface enhanced Raman scattering arrays fabricated by soft-lithography for label-free biomolecular detections in integrated microfluidics

    Science.gov (United States)

    Liu, Gang L.; Lee, Luke P.

    2005-08-01

    We describe a low-cost, ultrasensitive surface-enhanced Raman scattering (SERS) substrate in microfluidic biochips fabricated by soft lithography. A batch nanofabrication method is developed to create nanopillars structures on a silicon wafer as a master copy of molding, then the complementary nanowells structures on polydimethylsiloxane (PDMS) are created by soft lithography. The selective deposition of Ag thin film on the nanowells is applied to create SERS active sites before the integration with a glass-based microfluidic chip which functions as a sample delivery device and a transparent optical window for SERS spectroscopic imaging. Detections of Rhodamine 6G and adenosine SERS spectra are accomplished by using a 785nm laser with 300μW excitation power. The Raman scattering signal enhancement on the nanowell-based Ag SERS substrate is more than 107 times higher than the control sample (i.e. the smooth Ag layer on PDMS). Fabrication of ultrasensitive nanowell SERS substrate by economical and repeatable soft lithography method can contribute to the future microdevices for high throughput screening of functional genomics, proteomics, and cellular activities.

  17. Label-free detection and identification of waterborne parasites using a microfluidic multi-angle laser scattering system

    Science.gov (United States)

    Huang, Wei; Yang, Limei; Lei, Lei; Li, Feng

    2017-10-01

    A microfluidic-based multi-angle laser scattering (MALS) system capable of acquiring scattering patterns of a single particle is designed and demonstrated. The system includes a sheathless nozzle microfluidic glass chip, and an on-chip MALS unit being in alignment with the nozzle exit in the chip. The size and relative refractive indices (RI) of polystyrene (PS) microspheres were deduced with accuracies of 60 nm and 0.002 by comparing the experimental scattering patterns with theoretical ones. We measured scattering patterns of waterborne parasites i.e., Cryptosporidium parvum (C.parvum) and Giardia lamblia (G. lamblia), and some other representative species suspended in deionized water at a maximum flow rate of 12 μL/min, and a maximum of 3000 waterborne parasites can be identified within one minute with a mean accuracy higher than 96% by classification of distinctive scattering patterns using a support-vector-machine (SVM) algorithm. The system provides a promising tool for label-free detection of waterborne parasites and other biological contaminants.

  18. MEMS in microfluidic channels.

    Energy Technology Data Exchange (ETDEWEB)

    Ashby, Carol Iris Hill; Okandan, Murat; Michalske, Terry A.; Sounart, Thomas L.; Matzke, Carolyn M.

    2004-03-01

    Microelectromechanical systems (MEMS) comprise a new class of devices that include various forms of sensors and actuators. Recent studies have shown that microscale cantilever structures are able to detect a wide range of chemicals, biomolecules or even single bacterial cells. In this approach, cantilever deflection replaces optical fluorescence detection thereby eliminating complex chemical tagging steps that are difficult to achieve with chip-based architectures. A key challenge to utilizing this new detection scheme is the incorporation of functionalized MEMS structures within complex microfluidic channel architectures. The ability to accomplish this integration is currently limited by the processing approaches used to seal lids on pre-etched microfluidic channels. This report describes Sandia's first construction of MEMS instrumented microfluidic chips, which were fabricated by combining our leading capabilities in MEMS processing with our low-temperature photolithographic method for fabricating microfluidic channels. We have explored in-situ cantilevers and other similar passive MEMS devices as a new approach to directly sense fluid transport, and have successfully monitored local flow rates and viscosities within microfluidic channels. Actuated MEMS structures have also been incorporated into microfluidic channels, and the electrical requirements for actuation in liquids have been quantified with an elegant theory. Electrostatic actuation in water has been accomplished, and a novel technique for monitoring local electrical conductivities has been invented.

  19. Separation followed by direct SERS detection of explosives on a novel black silicon multifunctional nanostructured surface prepared in a microfluidic channel

    DEFF Research Database (Denmark)

    Talian, Ivan; Hübner, Jörg

    2013-01-01

    The article describes the multifunctionality of a novel black silicon (BS) nanostructured surface covered with a thin layer of noble metal prepared in the a microfluidic channel. It is focused on the separation properties of the BS substrate with direct detection of the separated analytes utilizing...

  20. Microfluidics and nanoparticles based amperometric biosensor for the detection of cyanobacteria (Planktothrix agardhii NIVA-CYA 116) DNA.

    Science.gov (United States)

    Ölcer, Zehra; Esen, Elif; Ersoy, Aylin; Budak, Sinan; Sever Kaya, Dilek; Yağmur Gök, Mehmet; Barut, Serkan; Üstek, Duran; Uludag, Yildiz

    2015-08-15

    Some of the cyanobacteria produce protease inhibitor oligopeptides such as cyanopeptolins and cause drinking water contamination; hence, their detection has great importance to monitor the well-being of water sources that is used for human consumption. In the current study, a fast and sensitive nucleic acid biosensor assay has been described where cyanopeptolin coding region of one of the cyanobacteria (Planktothrix agardhii NIVA-CYA 116) genome has been used as target for monitoring of the fresh water resources. A biochip that has two sets of Au electrode arrays, each consist of shared reference/counter electrodes and 3 working electrodes has been used for the assay. The biochip has been integrated to a microfluidics system and all steps of the assay have been performed during the reagent flow to achieve fast and sensitive DNA detection. On-line hybridization of the target on to the capture probe immobilized surface resulted in a very short assay duration with respect to the conventional static assays. The binding of the avidin and enzyme modified Au nanoparticles to the biotinylated detection probe and the subsequent injection of the substrate enabled a real-time amperometric measurement with a detection limit of 6×10(-12) M target DNA (calibration curve r(2)=0.98). The developed assay enables fast and sensitive detection of cyanopeptolin producing cyanobacteria from freshwater samples and hence shows a promising technology for toxic microorganism detection from environmental samples.

  1. Integrated microfluidic system with automatic sampling for permanent molecular and antigen-based detection of CBRNE-related pathogens

    Science.gov (United States)

    Becker, Holger; Schattschneider, Sebastian; Klemm, Richard; Hlawatsch, Nadine; Gärtner, Claudia

    2015-03-01

    The continuous monitoring of the environment for lethal pathogens is a central task in the field of biothreat detection. Typical scenarios involve air-sampling in locations such as public transport systems or large public events and a subsequent analysis of the samples by a portable instrument. Lab-on-a-chip technologies are one of the promising technological candidates for such a system. We have developed an integrated microfluidic system with automatic sampling for the detection of CBRNE-related pathogens. The chip contains a two-pronged analysis strategy, on the one hand an immunological track using antibodies immobilized on a frit and a subsequent photometric detection, on the other hand a molecular biology approach using continuous-flow PCR with a fluorescence end-point detection. The cartridge contains two-component molded rotary valve to allow active fluid control and switching between channels. The accompanying instrument contains all elements for fluidic and valve actuation, thermal control, as well as the two detection modalities. Reagents are stored in dedicated reagent packs which are connected directly to the cartridge. With this system, we have been able to demonstrate the detection of a variety of pathogen species.

  2. Microfluidic Immuno-Biochip for Detection of Breast Cancer Biomarkers Using Hierarchical Composite of Porous Graphene and Titanium Dioxide Nanofibers.

    Science.gov (United States)

    Ali, Md Azahar; Mondal, Kunal; Jiao, Yueyi; Oren, Seval; Xu, Zhen; Sharma, Ashutosh; Dong, Liang

    2016-08-17

    We report on a label-free microfluidic immunosensor with femtomolar sensitivity and high selectivity for early detection of epidermal growth factor receptor 2 (EGFR2 or ErbB2) proteins. This sensor utilizes a uniquely structured immunoelectrode made of porous hierarchical graphene foam (GF) modified with electrospun carbon-doped titanium dioxide nanofibers (nTiO2) as an electrochemical working electrode. Due to excellent biocompatibility, intrinsic surface defects, high reaction kinetics, and good stability for proteins, anatase nTiO2 are ideal for electrochemical sensor applications. The three-dimensional and porous features of GF allow nTiO2 to penetrate and attach to the surface of the GF by physical adsorption. Combining GF with functional nTiO2 yields high charge transfer resistance, large surface area, and porous access to the sensing surface by the analyte, resulting in new possibilities for the development of electrochemical immunosensors. Here, the enabling of EDC-NHS chemistry covalently immobilized the antibody of ErbB2 (anti-ErbB2) on the GF-nTiO2 composite. To obtain a compact sensor architecture, the composite working electrode was designed to hang above the gold counter electrode in a microfluidic channel. The sensor underwent differential pulse voltammetry and electrochemical impedance spectroscopy to quantify breast cancer biomarkers. The two methods had high sensitivities of 0.585 μA μM(-1) cm(-2) and 43.7 kΩ μM(-1) cm(-2) in a wide concentration range of target ErbB2 antigen from 1 × 10(-15) M (1.0 fM) to 0.1 × 10(-6) M (0.1 μM) and from 1 × 10(-13) M (0.1 pM) to 0.1 × 10(-6) M (0.1 μM), respectively. Utilization of the specific recognition element, i.e., anti-ErbB2, results in high specificity, even in the presence of identical members of the EGFR family of receptor tyrosine kinases, such as ErbB3 and ErbB4. Many promising applications in the field of electrochemical detection of chemical and biological species will derive from the

  3. Microfluidic electronics.

    Science.gov (United States)

    Cheng, Shi; Wu, Zhigang

    2012-08-21

    Microfluidics, a field that has been well-established for several decades, has seen extensive applications in the areas of biology, chemistry, and medicine. However, it might be very hard to imagine how such soft microfluidic devices would be used in other areas, such as electronics, in which stiff, solid metals, insulators, and semiconductors have previously dominated. Very recently, things have radically changed. Taking advantage of native properties of microfluidics, advances in microfluidics-based electronics have shown great potential in numerous new appealing applications, e.g. bio-inspired devices, body-worn healthcare and medical sensing systems, and ergonomic units, in which conventional rigid, bulky electronics are facing insurmountable obstacles to fulfil the demand on comfortable user experience. Not only would the birth of microfluidic electronics contribute to both the microfluidics and electronics fields, but it may also shape the future of our daily life. Nevertheless, microfluidic electronics are still at a very early stage, and significant efforts in research and development are needed to advance this emerging field. The intention of this article is to review recent research outcomes in the field of microfluidic electronics, and address current technical challenges and issues. The outlook of future development in microfluidic electronic devices and systems, as well as new fabrication techniques, is also discussed. Moreover, the authors would like to inspire both the microfluidics and electronics communities to further exploit this newly-established field.

  4. Development of a Generic Microfluidic Device for Simultaneous Detection of Antibodies and Nucleic Acids in Oral Fluids

    Directory of Open Access Journals (Sweden)

    Zongyuan Chen

    2013-01-01

    Full Text Available A prototype dual-path microfluidic device (Rheonix CARD capable of performing simultaneously screening (antigen or antibody and confirmatory (nucleic acid detection of pathogens is described. The device fully integrates sample processing, antigen or antibody detection, and nucleic acid amplification and detection, demonstrating rapid and inexpensive “sample-to-result” diagnosis with performance comparable to benchtop analysis. For the chip design, a modular approach was followed allowing the optimization of individual steps in the sample processing process. This modular design provides great versatility accommodating different disease targets independently of the production method. In the detection module, a lateral flow (LF protocol utilizing upconverting phosphor (UCP reporters was employed. The nucleic acid (NA module incorporates a generic microtube containing dry reagents. Lateral flow strips and PCR primers determine the target or disease that is diagnosed. Diagnosis of HIV infection was used as a model to investigate the simultaneous detection of both human antibodies against the virus and viral RNA. The serological result is available in less than 30 min, and the confirmation by RNA amplification takes another 60 min. This approach combines a core serological portable diagnostic with a nucleic acid-based confirmatory test.

  5. Microfluidic chip based micro RNA detection through the combination of fluorescence and surface enhanced Raman scattering techniques

    Science.gov (United States)

    Wang, Zhile; Zong, Shenfei; Wang, Zhuyuan; Wu, Lei; Chen, Peng; Yun, Binfeng; Cui, Yiping

    2017-03-01

    We present a novel microfluidic chip based method for the detection of micro RNA (miRNA) via the combination of fluorescence and surface enhanced Raman scattering (SERS) spectroscopies. First, silver nanoparticles (Ag NPs) are immobilized onto a glass slide, forming a SERS enhancing substrate. Then a specificially designed molecular beacon (MB) is attached to the SERS substrate. The 3‧ end of the MB is decorated with a thiol group to facilitate the attachment of the MB, while the 5‧ end of the MB is labeled with an organic dye 6-FAM, which is used both as the fluorophore and SERS reporter. In the absence of target miRNA, the MB will form a hairpin structure, making 6-FAM close to the Ag NPs. Hence, the fluorescence of 6-FAM will be quenched and the Raman signal of 6-FAM will be enhanced. On the contrary, with target miRNA present, hybridization between the miRNA and MB will unfold the MB and increase the distance between 6-FAM and the Ag NPs. Thus the fluorescence of 6-FAM will recover and the SERS signal of 6-FAM will decrease. So the target miRNA will simultaneously introduce opposite changing trends in the intensities of the fluorescence and SERS signals. By combining the opposite changes in the two optical spectra, an improved sensitivity and linearity toward the target miRNA is achieved as compared with using solely fluorescence or SERS. Moreover, introducing the microfluidic chip can reduce the reaction time, reagent dosage and complexity of detection. With the improved sensitivity and simplicity, we anticipate that the presented method can have great potential in the investigation of miRNA related diseases.

  6. Droplet microfluidics based microseparation systems.

    Science.gov (United States)

    Xiao, Zhiliang; Niu, Menglei; Zhang, Bo

    2012-06-01

    Lab on a chip (LOC) technology is a promising miniaturization approach. The feature that it significantly reduced sample consumption makes great sense in analytical and bioanalytical chemistry. Since the start of LOC technology, much attention has been focused on continuous flow microfluidic systems. At the turn of the century, droplet microfluidics, which was also termed segmented flow microfluidics, was introduced. Droplet microfluidics employs two immiscible phases to form discrete droplets, which are ideal vessels with confined volume, restricted dispersion, limited cross-contamination, and high surface area. Due to these unique features, droplet microfluidics proves to be a versatile tool in microscale sample handling. This article reviews the utility of droplet microfluidics in microanalytical systems with an emphasize on separation science, including sample encapsulation at ultra-small volume, compartmentalization of separation bands, isolation of droplet contents, and related detection techniques.

  7. Detection of a live cell in a microfluidic system by scanning capacitance microscopy

    Science.gov (United States)

    Sung, S. Y.; Yi, I. J.; Choi, Y. J.; Kim, J. Y.; Kim, Y. S.; Kang, C. J.

    2007-03-01

    In recent years, many studies on the biosensors using a microfluidic system have been performed. The system fabricated with polydimethylsiloxane (PDMS) has many advantages such that it is portable, disposable, cost effective, and automatable. Scanning capacitance microscope (SCM) that has a good capacitance pickup sensor attached to an atomic force microscope (AFM) is capable of measuring the capacitance variation with a resolution of better than 10-18F/V between a conducting tip and the sample. In this work, we present possibility of SCM as a biosensor by measuring a live cell which flows in the microchannel. By measuring the consecutive capacitance line profiles of a cell, which represent the charge distribution of a cell surface resulting from the ion channel or cell activity, we can get more information on the cell analysis and provide one solution for the realization of a lab-on-a-chip.

  8. A 3D Microfluidic Chip for Electrochemical Detection of Hydrolysed Nucleic Bases by a Modified Glassy Carbon Electrode

    Directory of Open Access Journals (Sweden)

    Jana Vlachova

    2015-01-01

    Full Text Available Modification of carbon materials, especially graphene-based materials, has wide applications in electrochemical detection such as electrochemical lab-on-chip devices. A glassy carbon electrode (GCE modified with chemically alternated graphene oxide was used as a working electrode (glassy carbon modified by graphene oxide with sulphur containing compounds and Nafion for detection of nucleobases in hydrolysed samples (HCl pH = 2.9, 100 °C, 1 h, neutralization by NaOH. It was found out that modification, especially with trithiocyanuric acid, increased the sensitivity of detection in comparison with pure GCE. All processes were finally implemented in a microfluidic chip formed with a 3D printer by fused deposition modelling technology. As a material for chip fabrication, acrylonitrile butadiene styrene was chosen because of its mechanical and chemical stability. The chip contained the one chamber for the hydrolysis of the nucleic acid and another for the electrochemical detection by the modified GCE. This chamber was fabricated to allow for replacement of the GCE.

  9. Microfluidic paper-based analytical devices for colorimetric detection of urinary tract infection biomarkers on adult diapers.

    Science.gov (United States)

    Chaohao Chen; Tao Dong

    2015-08-01

    Urinary tract infections (UTI) are common infection diseases in elderly patients. The conventional method of detecting UTI involves the collection of significant urine samples from the elderly patients. However, this is a very difficult and time-consuming procedure. This paper addresses the development of a microfluidic paper-based analytical device (μPAD) to detect UTI from urine collected from adult diapers. The design and fabrication for the μPAD is shown. The fabrication process involves melting solid wax on top of filter paper using a hot plate, followed by pattern transfer using a mold with rubbed wax. To demonstrate the feasibility of the proposed method, the μPAD with deposited nitrite reagent had detected different concentrations of nitrite solutions from 0.5 ppm to 100 ppm spiked in urine samples. A calibration curve was obtained by plotting the gray scale intensity values against the various nitrite concentrations. The results showed that the proposed paper-based device holds great potential as low-cost, disposable solution to sensitively detect UTI markers in urine sampled from diapers.

  10. Silica nanoparticle-based microfluidic immunosensor with laser-induced fluorescence detection for the quantification of immunoreactive trypsin.

    Science.gov (United States)

    Seia, Marco A; Stege, Patricia W; Pereira, Sirley V; De Vito, Irma E; Raba, Julio; Messina, Germán A

    2014-10-15

    The purpose of this study was to develop a silica nanoparticle-based immunosensor with laser-induced fluorescence (LIF) as a detection system. The proposed device was applied to quantify the immunoreactive trypsin (IRT) in cystic fibrosis (CF) newborn screening. A new ultrasonic procedure was used to extract the IRT from blood spot samples collected on filter papers. After extraction, the IRT reacted immunologically with anti-IRT monoclonal antibodies immobilized on a microfluidic glass chip modified with 3-aminopropyl functionalized silica nanoparticles (APSN-APTES-modified glass chips). The bounded IRT was quantified by horseradish peroxidase (HRP)-conjugated anti-IRT antibody (anti-IRT-Ab) using 10-acetyl-3,7-dihydroxyphenoxazine (ADHP) as enzymatic mediator. The HRP catalyzed the oxidation of nonfluorescent ADHP to highly fluorescent resorufin, which was measured by LIF detector, using excitation lambda at 561nm and emission at 585nm. The detection limits (LODs) calculated for LIF detection and for a commercial enzyme-linked immunosorbent assay (ELISA) test kit were 0.87 and 4.2ngml(-1), respectively. The within- and between-assay variation coefficients for the LIF detection procedure were below 6.5%. The blood spot samples collected on filter papers were analyzed with the proposed method, and the results were compared with those of the reference ELISA method, demonstrating a potential usefulness for the clinical assessment of IRT during the early neonatal period.

  11. A microfluidic platform for transcription- and amplification-free detection of zepto-mole amounts of nucleic acid molecules.

    Science.gov (United States)

    Mayr, Reinhard; Haider, Michaela; Thünauer, Roland; Haselgrübler, Thomas; Schütz, Gerhard J; Sonnleitner, Alois; Hesse, Jan

    2016-04-15

    Here we report the development of a device for the transcription- and amplification-free detection of DNA and RNA molecules down to the zepto-mole range. A microfluidic chip with a built-in microarray was used for manipulation of nano-liter sample volumes. Specific staining and immobilization of the target molecules was achieved via a double hybridization approach thereby avoiding bias due to enzymatic processes like reverse transcription and PCR amplification. Therefore, target molecules were indirectly labeled by pre-hybridization to complementary Cy5-labeled probes. The remaining single-stranded portion of each target molecule could subsequently hybridize to complementary capture probes of a microarray. Thus a target-mediated immobilization of labeled DNA took place. By means of an ultra-sensitive fluorescence readout, all molecules hybridized to the microarray could be detected. The combination of minimized sample volume and single molecule detection yielded a detection limit of 39 fM (831 molecules in 35.4 nl assay volume) for target DNA and 16 fM (338 molecules) for target RNA after 1h on-chip hybridization.

  12. A microfluidic chip integrating DNA extraction and real-time PCR for the detection of bacteria in saliva.

    Science.gov (United States)

    Oblath, Emily A; Henley, W Hampton; Alarie, Jean Pierre; Ramsey, J Michael

    2013-04-07

    A microfluidic chip integrating DNA extraction, amplification, and detection for the identification of bacteria in saliva is described. The chip design integrated a monolithic aluminum oxide membrane (AOM) for DNA extraction with seven parallel reaction wells for real-time polymerase chain reaction (rtPCR) amplification of the extracted DNA. Samples were first heated to lyse target organisms and then added to the chip and filtered through the nanoporous AOM to extract the DNA. PCR reagents were added to each of the wells and the chip was thermocycled. Identification of Streptococcus mutans in a saliva sample is demonstrated along with the detection of 300 fg (100-125 copies) of both methicillin-susceptible Staphylococcus aureus (MSSA) and methicillin-resistant S. aureus (MRSA) genomic DNA (gDNA) spiked into a saliva sample. Multiple target species and strains of bacteria can be simultaneously identified in the same sample by varying the primers and probes used in each of the seven reaction wells. In initial tests, as little as 30 fg (8-12 copies) of MSSA gDNA in buffer has been successfully amplified and detected with this device.

  13. New advances in electrochemical biosensors for the detection of toxins: Nanomaterials, magnetic beads and microfluidics systems. A review

    Energy Technology Data Exchange (ETDEWEB)

    Reverté, Laia [IRTA, Carretera Poble Nou km. 5.5, 43540 Sant Carles de la Ràpita, Tarragona (Spain); Prieto-Simón, Beatriz [ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, Future Industries Institute, University of South Australia, SA 5095 (Australia); Campàs, Mònica, E-mail: monica.campas@irta.cat [IRTA, Carretera Poble Nou km. 5.5, 43540 Sant Carles de la Ràpita, Tarragona (Spain)

    2016-02-18

    The use of nanotechnology in bioanalytical devices has special advantages in the detection of toxins of interest in food safety and environmental applications. The low levels to be detected and the small size of toxins justify the increasing number of publications dealing with electrochemical biosensors, due to their high sensitivity and design versatility. The incorporation of nanomaterials in their development has been exploited to further increase their sensitivity, providing simple and fast devices, with multiplexed capabilities. This paper gives an overview of the electrochemical biosensors that have incorporated carbon and metal nanomaterials in their configurations for the detection of toxins. Biosensing systems based on magnetic beads or integrated into microfluidics systems have also been considered because of their contribution to the development of compact analytical devices. The roles of these materials, the methods used for their incorporation in the biosensor configurations as well as the advantages they provide to the analyses are summarised. - Highlights: • Nanomaterials improve the performance of electrochemical biosensors. • Carbon nanomaterials can act as electrocatalysts or label supports in biosensors. • Metal nanomaterials can act as nanostructured supports or labels in biosensors. • Magnetic beads are exploited as immobilisation supports and/or label carriers.

  14. Assembly-line manipulation of droplets in microfluidic platform for fluorescence encoding and simultaneous multiplexed DNA detection.

    Science.gov (United States)

    Chen, Jinyang; Zhou, Guohua; Liu, Yufei; Ye, Tai; Xiang, Xia; Ji, Xinghu; He, Zhike

    2015-03-01

    In this article, a new mode of droplets manipulation is presented and applied for simultaneous multiplexed DNA detection. We call this droplets manipulation, "assembly-line manipulation of droplets (ALMD)". Firstly, multiple droplets containing the same target mixtures are generated in the microchannel, and then fused with later generated different droplets containing corresponding probes, respectively. Finally, all the fused droplets were fluorescence imaged on-line and real-time. The successful implementation of droplets fluorescence encoding based on ALMD shows the reproducibility and accuracy of this manipulation mode. As a proof-of-concept application, the simultaneous multiplexed DNA detection was carried out through the model of human immunodeficiency virus (HIV) gene sequence and variola virus (small pox, VV) gene sequence based on ALMD in the microfluidic system. It is proved that this method achieves simultaneous multiplexed DNA measurements with a significantly time-saving way and without different dye-labelled probes or complex operation procedures. In addition, it reveals the possibility of high-throughput biosensing with simple chip design and detection equipment.

  15. Microfluidic bead-based multienzyme-nanoparticle amplification for detection of circulating tumor cells in the blood using quantum dots labels

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, He, E-mail: mzhang_he@126.com; Fu, Xin; Hu, Jiayi; Zhu, Zhenjun

    2013-05-24

    Graphical abstract: A microfluidic beads-based nucleic acid sensor for sensitive detection of circulating tumor cells (CTCs) in the blood using multienzyme-nanoparticle amplification and quantum dots labels was developed. The chip-based CTCs analysis could detect reverse transcription-polymerase chain reaction (RT-PCR) products of tumor cell as low as 1 tumor cell (e.g. CEA expressing cell) in 1 mL blood sample. This microfluidic beads-based nucleic acid sensor is a promising platform for disease-related nucleic acid molecules at the lowest level at their earliest incidence. -- Highlights: •Combination of microfluidic bead-based platform and enzyme–probe–AuNPs is proposed. •The developed nucleic acid sensor could respond to 5 fM of tumor associated DNA. •Microfluidic platform and multienzyme-labeled AuNPs greatly enhanced sensitivity. •The developed nucleic acid sensor could respond to RT-PCR products of tumor cell as low as 1 tumor cell in 1 mL blood sample. •We report a sensitive nucleic acid sensor for detection of circulating tumor cells. -- Abstract: This study reports the development of a microfluidic bead-based nucleic acid sensor for sensitive detection of circulating tumor cells in blood samples using multienzyme-nanoparticle amplification and quantum dot labels. In this method, the microbeads functionalized with the capture probes and modified electron rich proteins were arrayed within a microfluidic channel as sensing elements, and the gold nanoparticles (AuNPs) functionalized with the horseradish peroxidases (HRP) and DNA probes were used as labels. Hence, two signal amplification approaches are integrated for enhancing the detection sensitivity of circulating tumor cells. First, the large surface area of Au nanoparticle carrier allows several binding events of HRP on each nanosphere. Second, enhanced mass transport capability inherent from microfluidics leads to higher capture efficiency of targets because continuous flow within micro

  16. A high-throughput method for GMO multi-detection using a microfluidic dynamic array

    NARCIS (Netherlands)

    Brod, F.C.A.; Dijk, van J.P.; Voorhuijzen, M.M.; Dinon, A.Z.; Guimarães, L.H.S.; Scholtens, I.M.J.; Arisi, A.C.M.; Kok, E.J.

    2014-01-01

    The ever-increasing production of genetically modified crops generates a demand for high-throughput DNAbased methods for the enforcement of genetically modified organisms (GMO) labelling requirements. The application of standard real-time PCR will become increasingly costly with the growth of the nu

  17. Detection of Genetically Modified Food: Has Your Food Been Genetically Modified?

    Science.gov (United States)

    Brandner, Diana L.

    2002-01-01

    Explains the benefits and risks of genetically-modified foods and describes methods for genetically modifying food. Presents a laboratory experiment using a polymerase chain reaction (PCR) test to detect foreign DNA in genetically-modified food. (Contains 18 references.) (YDS)

  18. Detection of Genetically Modified Food: Has Your Food Been Genetically Modified?

    Science.gov (United States)

    Brandner, Diana L.

    2002-01-01

    Explains the benefits and risks of genetically-modified foods and describes methods for genetically modifying food. Presents a laboratory experiment using a polymerase chain reaction (PCR) test to detect foreign DNA in genetically-modified food. (Contains 18 references.) (YDS)

  19. Review on application of chemiluminescent detection for microfluidic chip%化学发光检测在微流控芯片中的应用综述

    Institute of Scientific and Technical Information of China (English)

    奚忠华; 许丹科

    2012-01-01

    A review is provided of the application of chemiluminescent detection for microfluidic chip in recent years. It is pointed out that microfluidic chip (also known as "lab on a chip" or "micro total analysis system") has increasingly attracted attention in the past two decades, due to its advantages including miniaturization, integration, and automation. Besides, it is also suggested that chemiluminescence detection has the advantages of simple facility, low background noise, and low costs for operation and maintenance. This makes it feasible to adopt chemiluminescence detection as a suitable detection technique for microfluidic chip.%综述了近年来化学发光检测在微流控芯片中的应用.指出微流控芯片(又称为“芯片实验室”或者“微型全分析系统”)因具有小型化、集成化和自动化等特点而在近20年来日益受到关注,而化学发光检测具有仪器结构简单、背景噪音低、操作和维护成本低等优点,非常适合用作微流控芯片的检测手段.

  20. Coupling liquid chromatography/mass spectrometry detection with microfluidic droplet array for label-free enzyme inhibition assay.

    Science.gov (United States)

    Wang, Xiu-Li; Zhu, Ying; Fang, Qun

    2014-01-07

    In this work, the combination of droplet-based microfluidics with liquid chromatography/mass spectrometry (LC/MS) was achieved, for providing a fast separation and high-information-content detection method for the analysis of nanoliter-scale droplets with complex compositions. A novel interface method was developed using an oil-covered droplet array chip to couple with an LC/MS system via a capillary sampling probe and a 4 nL injection valve without the need of a droplet extraction device. The present system can perform multistep operations including parallel enzyme inhibition reactions in nanoliter droplets, 4 nL sample injection, fast separation with capillary LC, and label-free detection with ESI-MS, and has significant flexibility in the accurate addressing and sampling of droplets of interest on demand. The system performance was evaluated using angiotensin I and angiotensin II as model samples, and the repeatabilities of peak area for angiotensin I and angiotensin II were 2.7% and 7.5% (RSD, n = 4), respectively. The present system was further applied to the screening for inhibitors of cytochrome P450 (CYP1A2) and measurement of the IC50 value of the inhibitor. The sample consumption for each droplet assay was 100 nL, which is reduced 10-100 times compared with conventional 384-multi-well plate systems usually used in high-throughput drug screening.

  1. Reagent-free and portable detection of Bacillus anthracis spores using a microfluidic incubator and smartphone microscope.

    Science.gov (United States)

    Hutchison, Janine R; Erikson, Rebecca L; Sheen, Allison M; Ozanich, Richard M; Kelly, Ryan T

    2015-09-21

    Bacillus anthracis is the causative agent of anthrax and can be contracted by humans and herbivorous mammals by inhalation, ingestion, or cutaneous exposure to bacterial spores. Due to its stability and disease potential, B. anthracis is a recognized biothreat agent and robust detection and viability methods are needed to identify spores from unknown samples. Here we report the use of smartphone-based microscopy (SPM) in combination with a simple microfluidic incubation device (MID) to detect 50 to 5000 B. anthracis Sterne spores in 3 to 5 hours. This technique relies on optical monitoring of the conversion of the ∼1 μm spores to the filamentous vegetative cells that range from tens to hundreds of micrometers in length. This distinguishing filament formation is unique to B. anthracis as compared to other members of the Bacillus cereus group. A unique feature of this approach is that the sample integrity is maintained, and the vegetative biomass can be removed from the chip for secondary molecular analysis such as PCR. Compared with existing chip-based and rapid viability PCR methods, this new approach reduces assay time by almost half, and is highly sensitive, specific, and cost effective.

  2. A multiplexed microfluidic PCR assay for sensitive and specific point-of-care detection of Chlamydia trachomatis.

    Directory of Open Access Journals (Sweden)

    Deborah Dean

    Full Text Available BACKGROUND: Chlamydia trachomatis (Ct is the most common cause of bacterial sexually transmitted diseases (STD worldwide. While commercial nucleic acid amplification tests (NAAT are available for Ct, none are rapid or inexpensive enough to be used at the point-of-care (POC. Towards the first Ct POC NAAT, we developed a microfluidic assay that simultaneously interrogates nine Ct loci in 20 minutes. METHODOLOGY AND PRINCIPAL FINDINGS: Endocervical samples were selected from 263 women at high risk for Ct STDs (∼35% prevalence. A head-to-head comparison was performed with the Roche-Amplicor NAAT. 129 (49.0% and 88 (33.5% samples were positive by multiplex and Amplicor assays, respectively. Sequencing resolved 71 discrepant samples, confirming 53 of 53 positive multiplex samples and 12 of 18 positive Amplicor samples. The sensitivity and specificity were 91.5% and 100%, and 62.4% and 95.9%, respectively, for multiplex and Amplicor assays. Positive and negative predictive values were 100% and 91%, and 94.1% and 68.6%, respectively. CONCLUSIONS: This is the first rapid multiplex approach to Ct detection, and the assay was also found to be superior to a commercial NAAT. In effect, nine simultaneous reactions significantly increased sensitivity and specificity. Our assay can potentially increase Ct detection in globally diverse clinical settings at the POC.

  3. Highly sensitive colorimetric detection of glucose and uric acid in biological fluids using chitosan-modified paper microfluidic devices.

    Science.gov (United States)

    Gabriel, Ellen F M; Garcia, Paulo T; Cardoso, Thiago M G; Lopes, Flavio M; Martins, Felipe T; Coltro, Wendell K T

    2016-08-07

    This paper describes the modification of microfluidic paper-based analytical devices (μPADs) with chitosan to improve the analytical performance of colorimetric measurements associated with enzymatic bioassays. Chitosan is a natural biopolymer extensively used to modify biosensing surfaces due to its capability of providing a suitable microenvironment for the direct electron transfer between an enzyme and a reactive surface. This hypothesis was investigated using glucose and uric acid (UA) colorimetric assays as model systems. The best colorimetric sensitivity for glucose and UA was achieved using a chromogenic solution composed of 4-aminoantipyrine and sodium 3,5-dichloro-2-hydroxy-benzenesulfonate (4-AAP/DHBS), which provided a linear response for a concentration range between 0.1 and 1.0 mM. Glucose and UA were successfully determined in artificial serum samples with accuracies between 87 and 114%. The limits of detection (LODs) found for glucose and UA assays were 23 and 37 μM, respectively. The enhanced analytical performance of chitosan-modified μPADs allowed the colorimetric detection of glucose in tear samples from four nondiabetic patients. The achieved concentration levels ranged from 130 to 380 μM. The modified μPADs offered analytical reliability and accuracy as well as no statistical difference from the values achieved through a reference method. Based on the presented results, the proposed μPAD can be a powerful alternative tool for non-invasive glucose analysis.

  4. Towards an integrated optofluidic system for highly sensitive detection of antibiotics in seawater incorporating bimodal waveguide photonic biosensors and complex, active microfluidics

    Science.gov (United States)

    Szydzik, C.; Gavela, A. F.; Roccisano, J.; Herranz de Andrés, S.; Mitchell, A.; Lechuga, L. M.

    2016-12-01

    We present recent results on the realisation and demonstration of an integrated optofluidic lab-on-a-chip measurement system. The system consists of an integrated on-chip automated microfluidic fluid handling subsystem, coupled with bimodal nano-interferometer waveguide technology, and is applied in the context of detection of antibiotics in seawater. The bimodal waveguide (BMWG) is a highly sensitive label-free biosensor. Integration of complex microfluidic systems with bimodal waveguide technology enables on-chip sample handling and fluid processing capabilities and allows for significant automation of experimental processes. The on-chip fluid-handling subsystem is realised through the integration of pneumatically actuated elastomer pumps and valves, enabling high temporal resolution sample and reagent delivery and facilitating multiplexed detection processes.

  5. GARD: a genetic algorithm for recombination detection

    National Research Council Canada - National Science Library

    Kosakovsky Pond, Sergei L; Posada, David; Gravenor, Michael B; Woelk, Christopher H; Frost, Simon D W

    2006-01-01

    .... We developed a likelihood-based model selection procedure that uses a genetic algorithm to search multiple sequence alignments for evidence of recombination breakpoints and identify putative recombinant sequences...

  6. Electrowetting on dielectric digital microfluidic platform with nanostructured biosensor interface for enhanced two-dimensional surface plasmon resonance imaging detection

    Science.gov (United States)

    Malic, Lidija

    The sensitive and specific detection of biomolecular interactions is at the heart of many routine analyses in fundamental research, medical diagnosis and environmental monitoring. In contrast to laborious and costly multiwell plate assays, recent years have witnessed a significant progress in miniaturized and integrated biosensors, such as surface plasmon resonance (SPR), tailored to these applications. While the design of various SPR biosensors has been described in literature, a robust, multichannel, low-cost and highly sensitive solution has not yet been presented. Specifically, an integrated system that can allow surface functionalization in array format, low-volume multichannel fluidic interfacing, and increased sensitivity is sought. This thesis describes a novel electro-wetting-on-dielectric (EWOD) digital microfluidic device with integrated nanostructured biosensor interface that addresses the aforementioned issues for enhanced surface plasmon resonance imaging (SPRi) detection. We have taken the opportunity of the most recent advances in microfabrication, nanotechnology and SPR technique to develop this integrated platform. EWOD device is employed for the dynamic immobilization of bioreceptors on SPRi biosensor surface in an array fashion from sub-muL volume solutions. Programmable EWOD electric interface allows the application of an electric field at the biosensor surface for active control of the immobilized probe density and orientation, enhancing SPRi detection. Two-dimensional SPRi detection is achieved by coupling the EWOD device to SPRi instrumentation. Parallel manipulation of individual droplets allows more efficient exploitation of the biosensor surface by separating different samples for simultaneous and selective SPRi detection. Periodic gold structures (nanoposts, nanogratings and nanogrooves) residing on a surface of glass and plastic substrates are investigated to improve the SPRi sensitivity. The corresponding electromagnetic field

  7. On-Chip Microfluidic Components for In Situ Analysis, Separation, and Detection of Amino Acids

    Science.gov (United States)

    Zheng, Yun; Getty, Stephanie; Dworkin, Jason; Balvin, Manuel; Kotecki, Carl

    2013-01-01

    The Astrobiology Analytical Laboratory at GSFC has identified amino acids in meteorites and returned cometary samples by using liquid chromatography-electrospray ionization time-of-flight mass spectrometry (LCMS). These organic species are key markers for life, having the property of chirality that can be used to distinguish biological from non-biological amino acids. One of the critical components in the benchtop instrument is liquid chromatography (LC) analytical column. The commercial LC analytical column is an over- 250-mm-long and 4.6-mm-diameter stainless steel tube filled with functionized microbeads as stationary phase to separate the molecular species based on their chemistry. Miniaturization of this technique for spaceflight is compelling for future payloads for landed missions targeting astrobiology objectives. A commercial liquid chromatography analytical column consists of an inert cylindrical tube filled with a stationary phase, i.e., microbeads, that has been functionalized with a targeted chemistry. When analyte is sent through the column by a pressurized carrier fluid (typically a methanol/ water mixture), compounds are separated in time due to differences in chemical interactions with the stationary phase. Different species of analyte molecules will interact more strongly with the column chemistry, and will therefore take longer to traverse the column. In this way, the column will separate molecular species based on their chemistry. A lab-on-chip liquid analysis tool was developed. The microfluidic analytical column is capable of chromatographically separating biologically relevant classes of molecules based on their chemistry. For this analytical column, fabrication, low leak rate, and stationary phase incorporation of a serpentine microchannel were demonstrated that mimic the dimensions of a commercial LC column within a 5 10 1 mm chip. The microchannel in the chip has a 75- micrometer-diameter oval-shaped cross section. The serpentine

  8. Aptamer-functionalized nanoparticles for surface immobilization-free electrochemical detection of cortisol in a microfluidic device.

    Science.gov (United States)

    Sanghavi, Bankim J; Moore, John A; Chávez, Jorge L; Hagen, Joshua A; Kelley-Loughnane, Nancy; Chou, Chia-Fu; Swami, Nathan S

    2016-04-15

    Monitoring the periodic diurnal variations in cortisol from small volume samples of serum or saliva is of great interest, due to the regulatory role of cortisol within various physiological functions and stress symptoms. Current detection assays are immunologically based and require cumbersome antibody immobilization chemistries, thereby limiting the assay versatility, kinetics, and reproducibility. We present a quantitative aptamer-based detection methodology for cortisol that does not require target labeling, capture probe immobilization on the detection surface or wash steps prior to readout. Using a recognition system of aptamer functionalized gold nanoparticles pre-bound with electro-active triamcinolone, the cortisol level is detected based on its competitive binding to the aptamer by following signal from the displaced triamcinolone using square wave voltammetry at patterned graphene-modified electrodes in a microfluidic or nanoslit device. Due to the 3D analyte diffusion profile at the aptamer interface and the ability to enhance the surface area for cortisol capture, this assay shows signal linearity over a five-log analyte concentration range (10 μg/mL to 30 pg/mL) and exhibits rapid binding kinetics with cortisol versus other glucocorticoids, as apparent from the absence of interferences from estradiol, testosterone and progesterone. The assay is carried out within the biologically relevant range for glucocorticoids in serum and saliva matrices, and benchmarked versus ELISA and radioimmunoassays. Based on absence of cumbersome surface immobilization and wash steps for carrying out this assay, its quantitative signal characteristics and its ability to resist interferences from other glucocorticoids, we envision its application towards routine monitoring of cortisol within bio-fluids.

  9. Polymer-Based Microfluidic Devices for Pharmacy, Biology and Tissue Engineering

    Directory of Open Access Journals (Sweden)

    Kerstin Ramser

    2012-07-01

    Full Text Available This paper reviews microfluidic technologies with emphasis on applications in the fields of pharmacy, biology, and tissue engineering. Design and fabrication of microfluidic systems are discussed with respect to specific biological concerns, such as biocompatibility and cell viability. Recent applications and developments on genetic analysis, cell culture, cell manipulation, biosensors, pathogen detection systems, diagnostic devices, high-throughput screening and biomaterial synthesis for tissue engineering are presented. The pros and cons of materials like polydimethylsiloxane (PDMS, polymethylmethacrylate (PMMA, polystyrene (PS, polycarbonate (PC, cyclic olefin copolymer (COC, glass, and silicon are discussed in terms of biocompatibility and fabrication aspects. Microfluidic devices are widely used in life sciences. Here, commercialization and research trends of microfluidics as new, easy to use, and cost-effective measurement tools at the cell/tissue level are critically reviewed.

  10. Direct-writing colloidal photonic crystal microfluidic chips by inkjet printing for label-free protein detection.

    Science.gov (United States)

    Shen, Weizhi; Li, Mingzhu; Ye, Changqing; Jiang, Lei; Song, Yanlin

    2012-09-07

    Integrating photonic crystals (PC) into microfluidic systems has attracted immense interest for its novel functions. However, it is still a great challenge to fabricate PC microfluidic chips rapidly with complex functions. In this work, a direct-writing colloidal PC microchannel was firstly achieved by inkjet printing and was used for the surface-tension-confined microfluidic immune assay. PC channels with different structure colors have been successfully integrated on one chip. The fabricated chip has the advantages of rapid fabrication, quick fluidic transport and can monitor the fluidic fluxion using the naked eye. Utilizing this PC microfluidic chip, a colorimetric label-free immune assay was realized without nonspecific adsorption interference of the target.

  11. Quantifying the lag time to detect barriers in landscape genetics

    Science.gov (United States)

    E. L. Landguth; S. A Cushman; M. K. Schwartz; K. S. McKelvey; M. Murphy; G. Luikart

    2010-01-01

    Understanding how spatial genetic patterns respond to landscape change is crucial for advancing the emerging field of landscape genetics. We quantified the number of generations for new landscape barrier signatures to become detectable and for old signatures to disappear after barrier removal. We used spatially explicit, individualbased simulations to examine the...

  12. Imprint Molding of a Microfluidic Optical Cell on Thermoplastics with Reduced Surface Roughness for the Detection of Copper Ions.

    Science.gov (United States)

    Wu, Jing; Lee, Nae Yoon

    2016-01-01

    Here, we introduce a simple and facile technique for fabricating microfluidic optical cells by utilizing a micropatterned polymer mold, followed by imprinting on thermoplastic substrates. This process has reduced the surface roughness of the microchannel, making it suitable for microscale optical measurements. The micropatterned polymer mold was fabricated by first micromilling on a poly(methylmethacrylate) (PMMA) substrate, and then transferring the micropattern onto an ultraviolet (UV)-curable optical adhesive. After an anti-adhesion treatment of the polymer mold fabricated using the UV-curable optical adhesive, the polymer mold was used repeatedly for imprinting onto various thermoplastics, such as PMMA, polycarbonate (PC), and poly(ethyleneterephthalate) (PET). The roughness values for the PMMA, PC, and PET microchannels were approximately 11.3, 20.3, and 14.2 nm, respectively, as compared to those obtained by micromilling alone, which were 15.9, 76.8, and 207.5 nm, respectively. Using the imprint-molded thermoplastic optical cell, rhodamine B and copper ions were successfully quantified. The reduced roughness of the microchannel surface resulted in improved sensitivity and reduced noise, paving the way for integration of the detection module so as to realize totally integrated microdevices.

  13. Development of a Microfluidic-Based Optical Sensing Device for Label-Free Detection of Circulating Tumor Cells (CTCs Through Their Lactic Acid Metabolism

    Directory of Open Access Journals (Sweden)

    Tzu-Keng Chiu

    2015-03-01

    Full Text Available This study reports a microfluidic-based optical sensing device for label-free detection of circulating tumor cells (CTCs, a rare cell species in blood circulation. Based on the metabolic features of cancer cells, live CTCs can be quantified indirectly through their lactic acid production. Compared with the conventional schemes for CTC detection, this label-free approach could prevent the biological bias due to the heterogeneity of the surface antigens on cancer cells. In this study, a microfluidic device was proposed to generate uniform water-in-oil cell-encapsulating micro-droplets, followed by the fluorescence-based optical detection of lactic acid produced within the micro-droplets. To test its feasibility to quantify cancer cells, experiments were carried out. Results showed that the detection signals were proportional to the number of cancer cells within the micro-droplets, whereas such signals were insensitive to the existence and number of leukocytes within. To further demonstrate its feasibility for cancer cell detection, the cancer cells with known cell number in a cell suspension was detected based on the method. Results revealed that there was no significant difference between the detected number and the real number of cancer cells. As a whole, the proposed method opens up a new route to detect live CTCs in a label-free manner.

  14. High-Throughput DNA Array for SNP Detection of KRAS Gene Using a Centrifugal Microfluidic Device.

    Science.gov (United States)

    Sedighi, Abootaleb; Li, Paul C H

    2016-01-01

    Here, we describe detection of single nucleotide polymorphism (SNP) in genomic DNA samples using a NanoBioArray (NBA) chip. Fast DNA hybridization is achieved in the chip when target DNAs are introduced to the surface-arrayed probes using centrifugal force. Gold nanoparticles (AuNPs) are used to assist SNP detection at room temperature. The parallel setting of sample introduction in the spiral channels of the NBA chip enables multiple analyses on many samples, resulting in a technique appropriate for high-throughput SNP detection. The experimental procedure, including chip fabrication, probe array printing, DNA amplification, hybridization, signal detection, and data analysis, is described in detail.

  15. Improved Genetic Algorithm Application in Textile Defect Detection

    Institute of Scientific and Technical Information of China (English)

    GENG Zhao-feng; Li Bei-bei; ZHAO Zhi-hong

    2007-01-01

    Based on an efficient improved genetic algorithm,a pattern recognition approach is represented for textile defects inspection. An image process is developed to automatically detect the drawbacks on textile caused by three circumstances: break, dual, and jump of yams. By statistic method, some texture feature values of the image with defects points can be achieved. Therefore, the textile defects are classified properly. The advanced process of the defect image is done. Image segmentation is realized by an improved genetic algorithm to detect the defects. This method can be used to automatically classify and detect textile defects. According to different users' requirements, ifferent types of textile material can be detected.

  16. 滤纸微流控设备集成电化学检测%Integration of Paper - based Microfluidic Devices with Electrochemical Detection

    Institute of Scientific and Technical Information of China (English)

    唐帆; 邢宏龙; 毕连花; 郑虎祥; 王伟

    2012-01-01

    近年来,人们发现滤纸微流控设备相比于传统的微流控设备来说具有一次性使用、制作简单且成本更低的优点。简单综述了微流控设备的发展现状以及滤纸和电化学检测的相关特点,着重阐明了滤纸在微流控电化学检测中的应用,同时与商品化的检测仪相结合,为微流控设备未来商品化打下了坚实的基础。%Paper - based microfluidic devices are found that they are disposable, easy - to - fabricate, and lower - cost compared to traditional microfluidic devices. This paper presented an overview on the present state of microtluidic devices and the related characteristics of filter paper and electrochemical detection. Filter paper applicated in microfluidie devices coupled with electro- chemical detection is mainly introduced. Meanwhile, the integration of commercial detector will establish a firm foundation for the commercialization of microfluidic devices in the future.

  17. Edge detection of range images using genetic neural networks

    Institute of Scientific and Technical Information of China (English)

    FAN Jian-ying; DU Ying; ZHOU Yang; WANG Yang

    2009-01-01

    Due to the complexity and asymmetrical illumination, the images of object are difficult to be effectively segmented by some routine method. In this paper, a kind of edge detection method based on image features and genetic algorithms neural network for range images was proposed. Fully considering the essential difference between an edge point and a noise point, some characteristic parameters were extracted from range maps as the input nodes of the network in the algorithm. Firstly, a genetic neural network was designed and implemented. The neural network is trained by genetic algorithm, and then genetic neural network algorithm is combined with the virtue of global optimization of genetic algorithm and the virtue of parallel computation of neural network, so that this algorithm is of good global property. The experimental results show that this method can get much faster and more accurate detection results than the classical differential algorithm, and has better anti-noise performance.

  18. Sensitive and Specific Biomimetic Lipid Coated Microfluidics to Isolate Viable Circulating Tumor Cells and Microemboli for Cancer Detection.

    Directory of Open Access Journals (Sweden)

    Jia-Yang Chen

    Full Text Available Here we presented a simple and effective membrane mimetic microfluidic device with antibody conjugated supported lipid bilayer (SLB "smart coating" to capture viable circulating tumor cells (CTCs and circulating tumor microemboli (CTM directly from whole blood of all stage clinical cancer patients. The non-covalently bound SLB was able to promote dynamic clustering of lipid-tethered antibodies to CTC antigens and minimized non-specific blood cells retention through its non-fouling nature. A gentle flow further flushed away loosely-bound blood cells to achieve high purity of CTCs, and a stream of air foam injected disintegrate the SLB assemblies to release intact and viable CTCs from the chip. Human blood spiked cancer cell line test showed the ~95% overall efficiency to recover both CTCs and CTMs. Live/dead assay showed that at least 86% of recovered cells maintain viability. By using 2 mL of peripheral blood, the CTCs and CTMs counts of 63 healthy and colorectal cancer donors were positively correlated with the cancer progression. In summary, a simple and effective strategy utilizing biomimetic principle was developed to retrieve viable CTCs for enumeration, molecular analysis, as well as ex vivo culture over weeks. Due to the high sensitivity and specificity, it is the first time to show the high detection rates and quantity of CTCs in non-metastatic cancer patients. This work offers the values in both early cancer detection and prognosis of CTC and provides an accurate non-invasive strategy for routine clinical investigation on CTCs.

  19. Paper-Based Microfluidic Device with a Gold Nanosensor to Detect Arsenic Contamination of Groundwater in Bangladesh

    Directory of Open Access Journals (Sweden)

    Mosfera A. Chowdury

    2017-03-01

    Full Text Available In this paper, we present a microfluidic paper-based analytical device (μPAD with a gold nanosensor functionalized with α-lipoic acid and thioguanine (Au–TA–TG to detect whether the arsenic level of groundwater from hand tubewells in Bangladesh is above or below the World Health Organization (WHO guideline level of 10 μg/L. We analyzed the naturally occurring metals present in Bangladesh groundwater and assessed the interference with the gold nanosensor. A method was developed to prevent interference from alkaline metals found in Bangladesh groundwater (Ca, Mg, K and Na by increasing the pH level on the μPADs to 12.1. Most of the heavy metals present in the groundwater (Ni, Mn, Cd, Pb, and Fe II did not interfere with the μPAD arsenic tests; however, Fe III was found to interfere, which was also prevented by increasing the pH level on the μPADs to 12.1. The μPAD arsenic tests were tested with 24 groundwater samples collected from hand tubewells in three different districts in Bangladesh: Shirajganj, Manikganj, and Munshiganj, and the predictions for whether the arsenic levels were above or below the WHO guideline level agreed with the results obtained from laboratory testing. The μPAD arsenic test is the first paper-based test validated using Bangladesh groundwater samples and capable of detecting whether the arsenic level in groundwater is above or below the WHO guideline level of 10 μg/L, which is a step towards enabling the villagers who collect and consume the groundwater to test their own sources and make decisions about where to obtain the safest water.

  20. Microfluidic cartridge with integrated array of amorphous silicon photosensors for chemiluminescence detection of viral DNA

    Directory of Open Access Journals (Sweden)

    M. Zangheri

    2016-03-01

    With this system, taking advantage of oligoprobes specificity, chemiluminescence detectability, and photosensor sensitivity, accurate quantification of target analytes down to 70 pmol L−1 was obtained for each B19 DNA genotype, with high specificity and multiplexing ability. Results confirm the good detection capabilities and assay applicability of the proposed system, prompting the development of innovative portable analytical devices with enhanced sensitivity and multiplexed capabilities.

  1. The feasibility of liquid sample microanalysis using polydimethylsiloxane microfluidic chips with in-channel and in-port laser-induced breakdown spectroscopy detection

    Science.gov (United States)

    Metzinger, Anikó; Nagy, Andrea; Gáspár, Attila; Márton, Zsuzsanna; Kovács-Széles, Éva; Galbács, Gábor

    2016-12-01

    This study describes the direct interfacing of polydimethylsiloxane (PDMS) microfluidic chips with laser-induced breakdown spectroscopy (LIBS) detection. The changes induced in the PDMS material by nanosecond laser ablation are briefly documented by using optical microscopy and scanning profilometry. The main part of the study focuses on the solution of technical and analytical problems of coupling single-pulse LIBS detection with PDMS microfluidic chips in order to assess the feasibility and performance of the concept of creating a lab-on-a-chip device with LIBS detection (LOC-LIBS). Multiple optical and sample presentation schemes including in-channel and in-port detection were tested, but it was found that LOC-LIBS is only viable and practical with in-port detection outside the chip. It was shown that LOC-LIBS in this configuration is capable of the trace speciation analysis of chromium using as little as 0.5 μL solution volume. The achieved absolute limit of detection was 2 ng.

  2. Ultrasensitive detection of dopamine using a carbon nanotube network microfluidic flow electrode.

    Science.gov (United States)

    Sansuk, Siriwat; Bitziou, Eleni; Joseph, Maxim B; Covington, James A; Boutelle, Martyn G; Unwin, Patrick R; Macpherson, Julie V

    2013-01-02

    The electrochemical measurement of dopamine (DA), in phosphate buffer solution (pH 7.4), with a limit of detection (LOD) of ∼5 pM in 50 μL (∼ 250 attomol) is achieved using a band electrode comprised of a sparse network of pristine single-walled carbon nanotubes (SWNTs), which covers dopamine (DA), reported herein, is significantly lower than previous reports using FIA-electrochemical detection. Furthermore, the SWNT electrodes can be used as grown, i.e., they do not require chemical modification or cleanup. The extremely low background signals of the SWNT electrodes, as a consequence of the sparse surface coverage and the low intrinsic capacitance of the SWNTs, means that no signal processing is required to measure the low currents for DA oxidation at trace levels. DA detection in artificial cerebral fluid is also possible with a LOD of ∼50 pM in 50 μL (∼2.5 fmol).

  3. Portable microfluidic raman system for rapid, label-free early disease signature detection

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Meiye [Sandia National Laboratories (SNL-CA), Livermore, CA (United States); Davis, Ryan Wesley [Sandia National Laboratories (SNL-CA), Livermore, CA (United States); Hatch, Anson [Sandia National Laboratories (SNL-CA), Livermore, CA (United States)

    2015-09-01

    In the early stages of infection, patients develop non-specific or no symptoms at all. While waiting for identification of the infectious agent, precious window of opportunity for early intervention is lost. The standard diagnostics require affinity reagents and sufficient pathogen titers to reach the limit of detection. In the event of a disease outbreak, triaging the at-risk population rapidly and reliably for quarantine and countermeasure is more important than the identification of the pathogen by name. To expand Sandia's portfolio of Biological threat management capabilities, we will utilize Raman spectrometry to analyze immune subsets in whole blood to rapidly distinguish infected from non-infected, and bacterial from viral infection, for the purpose of triage during an emergency outbreak. The goal of this one year LDRD is to determine whether Raman spectroscopy can provide label-free detection of early disease signatures, and define a miniaturized Raman detection system meeting requirements for low- resource settings.

  4. Combination of capillary micellar liquid chromatography with on-chip microfluidic chemiluminescence detection for direct analysis of buspirone in human plasma.

    Science.gov (United States)

    Al Lawati, Haider A J; Kadavilpparampu, Afsal Mohammed; Suliman, FakhrEldin O

    2014-09-01

    Microfluidic based chemiluminescence (CL) detector having novel channel design for enhanced mixing has been developed and investigated in terms of its applicability with micellar mode of liquid chromatography (MLC). The newly developed detector was found to be highly sensitive and an alternative detection technique to combine with capillary MLC. This combination was successfully employed for direct detection of a model analyte using Ru(III)-peroxydisulphate CL system. The selected analyte, buspirone hydrochloride (BUS), was detected selectively at therapeutic concentration levels in human plasma without any sample pretreatment. By incorporating eight flow split units within the spiral channel of microfluidic chip, an enhancement of 140% in CL emission was observed. We also evaluated the effect of non- ionic surfactant, Brij-35, which used as mobile phase modifier in MLC, on CL emission. The CL signal was improved by 52% compared to aqueous-organic mobile phase combinations. Various parameters influencing the micellar chromatographic performance and the CL emission were optimized. This allowed highly sensitive analysis of BUS with limit of detection (LOD) of 0.27 ng mL(-1) (3σ/s) and limit of quantification (LOQ) of 0.89 ng mL(-1) (10σ/s). The analyte recovery from human plasma at three different concentration level ranges from 88% to 96% (RSD 1.9-5.3%). The direct analysis of BUS in human plasma was achieved within 6 min. Therefore, combining microfluidic CL detection with micellar mode of separation is an efficient, cost-effective and highly sensitive technique that can utilize MLC in its full capacity for various bioanalytical procedures.

  5. Small target detection using quantum genetic morphological filter

    Science.gov (United States)

    Deng, Lizhen; Zhu, Hu; Wei, Yantao; Lu, Guanmin; Wei, Yu

    2015-12-01

    Small target detection plays a crucial role in infrared warning and tracking systems. A background suppression method using morphological filter based on quantum genetic algorithm (QGMF) is presented to detect small targets in infrared image. Structure element of morphological filter is encoded and the best structure element is selected using quantum genetic algorithm. The optimized structure element is used for background suppression to detect small target. Experimental results demonstrate that QGMF has good performance in clutter suppression, and obtains higher signal-to-clutter ratio gain (SCRG) and background suppression factor (BSF) than the one using the fixed structure element with the same size.

  6. A Turbidity Test Based Centrifugal Microfluidics Diagnostic System for Simultaneous Detection of HBV, HCV, and CMV

    Directory of Open Access Journals (Sweden)

    Hung-Cheng Chang

    2015-01-01

    Full Text Available This paper presents a LAMP- (loop-mediated isothermal amplification- based lab-on-disk optical system that allows the simultaneous detection of hepatitis B virus, hepatitis C virus, and cytomegalovirus. The various flow stages are controlled in the proposed system using different balance among centrifugal pumping, Coriolis pumping, and the capillary force. We have implemented a servo system for positioning and speed control for the heating and centrifugal pumping. We have also successfully employed a polymer light-emitting diode section for turbidity detection. The easy-to-use one-click system can perform diagnostics in less than 1 hour.

  7. TMTI Task 1.6 Genetic Engineering Methods and Detection

    Energy Technology Data Exchange (ETDEWEB)

    Slezak, T; Lenhoff, R; Allen, J; Borucki, M; Vitalis, E; Gardner, S

    2009-12-04

    A large number of GE techniques can be adapted from other microorganisms to biothreat bacteria and viruses. Detection of GE in a microorganism increases in difficulty as the size of the genetic change decreases. In addition to the size of the engineered change, the consensus genomic sequence of the microorganism can impact the difficulty of detecting an engineered change in genomes that are highly variable from strain to strain. This problem will require comprehensive databases of whole genome sequences for more genetically variable biothreat bacteria and viruses. Preliminary work with microarrays for detecting synthetic elements or virulence genes and analytic bioinformatic approaches for whole genome sequence comparison to detect genetic engineering show promise for attacking this difficult problem but a large amount of future work remains.

  8. Low-level detection of Cryptosporidium parvum in field water using optical microfluidic biosensors

    Science.gov (United States)

    Angus, Scott V.; Kwon, Hyuck-Jin; Yoon, Jeong-Yeol

    2012-03-01

    Cryptosporidium parvum is a difficult-to-detect protozoan that causes diarrhea in the healthy adults and death in immunocompromised individuals. While it is easy to understand the transmission routes of Cryptosporidium, it is currently difficult to identify low concentrations of Cryptosporidium, especially when following EPA method 1623, which can easily require tens of liters of water to get a positive signal. The current detection method is unacceptable and severely inefficient when taking into account the time that goes into concentrating a sample, actual assays, and training associated with the assays. Using our method, it is possible to use only 15 μL of sample, which is an immunoagglutination assay that uses Mie scatter intensity changes to detect different Cryptosporidium concentrations. In addition to creating a standard curve using a clean sample matrix (i.e., phosphate buffered saline), field samples were collected from a chlorine treated swimming pool, a sump located on a farm, and a turtle pond. Each sample had different intensity changes but the trend represented within the data was the same. This assay has a detection limit of 100-101 oocysts/mL and can be done in as little as 10 minutes.

  9. Label-free protein detection using a microfluidic Coulter-counter device

    DEFF Research Database (Denmark)

    Rodriguez-Trujíllo, Romén; Ajine, Mohammad Akram; Orzan, A.;

    2014-01-01

    A new method for measuring specific protein concentrations in solutions has been developed. The technique makes use of the Coulter effect for detecting and sizing of micro-scaled objects suspended in a buffer fluid. The method is completely label-free as it is only based on the electrical readout...

  10. Mass spectrometric detection of short-lived drug metabolites generated in an electrochemical microfluidic chip.

    Science.gov (United States)

    van den Brink, Floris T G; Büter, Lars; Odijk, Mathieu; Olthuis, Wouter; Karst, Uwe; van den Berg, Albert

    2015-02-03

    The costs of drug development have been rising exponentially over the last six decades, making it essential to select drug candidates in the early drug discovery phases before proceeding to expensive clinical trials. Here, we present novel screening methods using an electrochemical chip coupled online to mass spectrometry (MS) or liquid chromatography (LC) and MS, to generate phase I and phase II drug metabolites and to demonstrate protein modification by reactive metabolites. The short transit time (∼4.5 s) between electrochemical oxidation and mass spectrometric detection, enabled by an integrated electrospray emitter, allows us to detect a short-lived radical metabolite of chlorpromazine which is too unstable to be detected using established test routines. In addition, a fast way to screen candidate drugs is established by recording real-time mass voltammograms, which allows one to identify the drug metabolites that are expected to be formed upon oxidation by applying a linear potential sweep and simultaneously detect oxidation products. Furthermore, detoxification of electrochemically generated reactive metabolites of paracetamol was mimicked by their adduct formation with the antioxidant glutathione. Finally, the potential toxicity of reactive metabolites can be investigated by the modification of proteins, which was demonstrated by modification of carbonic anhydrase I with electrochemically generated reactive metabolites of paracetamol. With this series of experiments, we demonstrate the potential of this electrochemical chip as a complementary tool for a variety of drug metabolism studies in the early stages of drug discovery.

  11. A compact multifunctional microfluidic platform for exploring cellular dynamics in real-time using electrochemical detection

    DEFF Research Database (Denmark)

    Zor, Kinga; Heiskanen, Arto; Caviglia, Claudia

    2014-01-01

    and electrochemical analysis platform with in-built fluid handling and detection, enabling complete cell based assays comprising on-line electrode cleaning, sterilization, surface functionalization, cell seeding, cultivation and electrochemical real-time monitoring of cellular dynamics. To demonstrate the versatility...

  12. Construction and characterisation of a modular microfluidic system: coupling magnetic capture and electrochemical detection

    DEFF Research Database (Denmark)

    Godino, N.; Snakenborg, Detlef; Kutter, Jörg Peter;

    2010-01-01

    , and a polycarbonate base where permanent magnets are hosted; these parts are designed to fit so that wire bonding and encapsulation are avoided. This system can perform bioassays over the surface of magnetic beads and uses only 50 mu L of bead suspension per assay. Following detection, captured beads are released...

  13. Portable microfluidic chip for detection of Escherichia coli in produce and blood

    Directory of Open Access Journals (Sweden)

    Wang S

    2012-05-01

    Full Text Available ShuQi Wang,1* Fatih Inci,1* Tafadzwa L Chaunzwa,1 Ajay Ramanujam,1 Aishwarya Vasudevan,1 Sathya Subramanian,1 Alexander Chi Fai Ip,1 Banupriya Sridharan,1 Umut Atakan Gurkan,1 Utkan Demirci,1,21Bio-Acoustic-MEMS in Medicine (BAMM Laboratory, Center for Biomedical Engineering, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02139, 2Harvard-MIT Health Sciences and Technology, Cambridge, MA, USA, *These authors contributed equally to this workAbstract: Pathogenic agents can lead to severe clinical outcomes such as food poisoning, infection of open wounds, particularly in burn injuries and sepsis. Rapid detection of these pathogens can monitor these infections in a timely manner improving clinical outcomes. Conventional bacterial detection methods, such as agar plate culture or polymerase chain reaction, are time-consuming and dependent on complex and expensive instruments, which are not suitable for point-of-care (POC settings. Therefore, there is an unmet need to develop a simple, rapid method for detection of pathogens such as Escherichia coli. Here, we present an immunobased microchip technology that can rapidly detect and quantify bacterial presence in various sources including physiologically relevant buffer solution (phosphate buffered saline [PBS], blood, milk, and spinach. The microchip showed reliable capture of E. coli in PBS with an efficiency of 71.8% ± 5% at concentrations ranging from 50 to 4,000 CFUs/mL via lipopolysaccharide binding protein. The limits of detection of the microchip for PBS, blood, milk, and spinach samples were 50, 50, 50, and 500 CFUs/mL, respectively. The presented technology can be broadly applied to other pathogens at the POC, enabling various applications including surveillance of food supply and monitoring of bacteriology in patients with burn wounds.Keywords: Escherichia coli, microchip, sepsis, food safety, point-of-care

  14. 3D-printed microfluidic magnetic preconcentrator for the detection of bacterial pathogen using an ATP luminometer and antibody-conjugated magnetic nanoparticles.

    Science.gov (United States)

    Park, Chanyong; Lee, Jinyeop; Kim, Yonghee; Kim, Jaewon; Lee, Jinkee; Park, Sungsu

    2017-01-01

    Various types of microfluidic systems have been developed to detect bacterial pathogens. However, most of these require enrichment steps that take at least several hours when detecting bacteria that are present with a low number of cells and, in addition, fabrication requires complicated assembly steps. In this study, we report the development of 3D microfluidic magnetic preconcentrator (3DμFMP) made of plastic via 3D printing without the need for any assembly. 3DμFMP could selectively preconcentrate enterohemorrhagic Escherichia coli O157:H7 in 100mL by a factor of 700 within 1h using antibody-conjugated magnetic nanoparticles (Ab-MNPs). With the combined use of an ATP luminometer, as low as 10 E. coli O157:H7 CFU (colony forming unit)/mL could be detected in blood. These results demonstrate the feasibility of 3DμFMP as a preconcentrator to improve the detection limit of existing bacterial detection systems.

  15. Combining motion analysis and microfluidics--a novel approach for detecting whole-animal responses to test substances.

    Directory of Open Access Journals (Sweden)

    Tabitha S Rudin-Bitterli

    Full Text Available Small, early life stages, such as zebrafish embryos are increasingly used to assess the biological effects of chemical compounds in vivo. However, behavioural screens of such organisms are challenging in terms of both data collection (culture techniques, drug delivery and imaging and data evaluation (very large data sets, restricting the use of high throughput systems compared to in vitro assays. Here, we combine the use of a microfluidic flow-through culture system, or BioWell plate, with a novel motion analysis technique, (sparse optic flow - SOF followed by spectral analysis (discrete Fourier transformation - DFT, as a first step towards automating data extraction and analysis for such screenings. Replicate zebrafish embryos housed in a BioWell plate within a custom-built imaging system were subject to a chemical exposure (1.5% ethanol. Embryo movement was videoed before (30 min, during (60 min and after (60 min exposure and SOF was then used to extract data on movement (angles of rotation and angular changes to the centre of mass of embryos. DFT was subsequently used to quantify the movement patterns exhibited during these periods and Multidimensional Scaling and ANOSIM were used to test for differences. Motion analysis revealed that zebrafish had significantly altered movements during both the second half of the alcohol exposure period and also the second half of the recovery period compared to their pre-treatment movements. Manual quantification of tail flicking revealed the same differences between exposure-periods as detected using the automated approach. However, the automated approach also incorporates other movements visible in the organism such as blood flow and heart beat, and has greater power to discern environmentally-driven changes in the behaviour and physiology of organisms. We suggest that combining these technologies could provide a highly efficient, high throughput assay, for assessing whole embryo responses to various

  16. Planar Microfluidic System Based on Electrophoresis for Detection of 130-nm Magnetic Labels for Biosensing

    Science.gov (United States)

    Takamura, Tsukasa; Morimoto, Yoshitaka; Sandhu, Adarsh

    2011-04-01

    Superparamagnetic beads (SPBs) used as magnetic labels offer potential for the realization of high sensitivity and low cost biosensors for point of care treatment (POCT). For better biomolecular affinity and higher sensitivity, it is desirable to use sub-200-nm-diameter SPBs comparable in size to actual biomolecules. However, the detection of small concentrations of such SPBs by magnetoresistive devices is extremely challenging due to small magnetic response of SPBs. As a solution to these limitations, we describe a simple detecting procedure where the capture of micro-SPBs by immobilized nano-target SPBs due to self-assembly induced by an external magnetic field, which was monitored under an optical microscope. Here we describe biosensing system based on self-assembly of micro-SPBs by nanoSPBs targets using a system without external pumps, thereby enabling greater miniaturization and portability.

  17. Design Optimization and Evaluation of a Bioluminescence Detection Part on a Microfluidic Device for in situ ATP Quantification

    Science.gov (United States)

    Aoki, Yusuke; Fukuba, Tatsuhiro; Yamamoto, Takatoki; Fujii, Teruo

    An integrated in situ analyzer for microbial ATP (IISA-ATP) has been developed with a microfluidic device as its core component to realize a compact and fully integrated system. In the system, a bioluminescence (luciferin—luciferase) reaction is conducted for ATP quantification. The microfluidic device has a coil-shaped microchannel for highly sensitive photo intensity measurement. In this paper, the concept of the IISA-ATP and optimization of the microchannel design to enhance sensitivity are presented. As a result of the optimization, linear correlation of the luminescence intensity with the ATP concentration in the range of 2 to 2 × 104 pM was achieved.

  18. An integrated hybrid system for genetic analysis combining EWOD sample preparation and magnetic detection

    Energy Technology Data Exchange (ETDEWEB)

    Brennan, Des; Dinca, Mihai; Aherne, Margaret; Galvin, Paul [Tyndall National Institute, University College, Cork, Lee Maltings, Prospect Row, Cork (Ireland); Jary, Dorothee; Peponnet, Christine [CEA-LETI, Department of Technology for Biology and Health, 17 Avenue Des Martyrs, 38054 Grenoble (France); Cardosa, Filipe; Freitas, Paolo, E-mail: des.brennan@tyndall.ie [INESC-MN, Rua Alves Redol, 9, 1000-029 Lisbon (Portugal)

    2011-08-17

    Over the last decade microelectronic technologies have delivered significant advances in devices for point of care diagnostics. Complex microfluidic systems integrate components such as valves, pumps etc. to manipulate liquids. In recent years, the drive is to combine biochemical protocols in a single system, delivering 'sample in answer out'. An Electrowetting on Dielectric (EWOD) device offers the possibility to move and manipulate 64nl volumes implementing biochemical processes, while the magnetic sensor facilitates hybridisation detection. We outline an injection molding approach where EWOD and magnetic devices are integrated into a hybrid microfluidic system with the potential to implement 'sample in answer out' biological protocols.

  19. An integrated hybrid system for genetic analysis combining EWOD sample preparation and magnetic detection

    Science.gov (United States)

    Brennan, Des; Jary, Dorothee; Peponnet, Christine; Cardosa, Filipe; Freitas, Paolo; Dinca, Mihai; Aherne, Margaret; Galvin, Paul

    2011-08-01

    Over the last decade microelectronic technologies have delivered significant advances in devices for point of care diagnostics. Complex microfluidic systems integrate components such as valves, pumps etc. to manipulate liquids. In recent years, the drive is to combine biochemical protocols in a single system, delivering "sample in answer out". An Electrowetting on Dielectric (EWOD) device offers the possibility to move and manipulate 64nl volumes implementing biochemical processes, while the magnetic sensor facilitates hybridisation detection. We outline an injection molding approach where EWOD and magnetic devices are integrated into a hybrid microfluidic system with the potential to implement "sample in answer out" biological protocols.

  20. Detection of genetically modified organisms by electrochemiluminescence PCR method.

    Science.gov (United States)

    Liu, Jinfeng; Xing, Da; Shen, Xingyan; Zhu, Debin

    2004-10-15

    With the development of biotechnology, more and more genetically modified organisms (GMOs) have entered commercial market. Because of the safety concerns, detection and characterization of GMOs have attracted much attention recently. In this study, electrochemiluminescence polymerase chain reaction (ECL-PCR) combined with hybridization technique was applied to detect the GMOs in genetically modified (GM) soybeans and papayas for the first time. Whether the soybeans and the papayas contain GM components was discriminated by detecting the Cauliflower mosaic virus 35S (CaMV35S) promoter. The experiment results show that the detection limit for CaMV35S promoter is 100 fmol, and the GM components can be clearly identified in GM soybeans and papayas. The technique may provide a new means in GMOs detection due to its simplicity and high efficiency.

  1. Fluorescence detection test by black printed circuit board based microfluidic channel for polymerase chain reaction.

    Science.gov (United States)

    Hwang, Ji-Soo; Kim, Yu-Seop; Song, Hye-Jeong; Kim, Jong-Dae; Park, Chan-Young

    2015-01-01

    This paper proposes the optimal structure of a PCB-based micro PCR chip constructed on a PCB substrate using commercial adhesive tapes and plastic covers. The solder mask of the PCB substrate was coated black, and the area where the reaction chamber is attached was legend printed with white silk to minimize the noise during fluorescence detection. The performance of the PCR and fluorescence detection was compared using 6 types of reaction chambers, each made with different double-sided tapes. Three of the chambers were unsuccessful in completing the PCR. The performance of the other three chambers that successfully amplified DNA was compared using Taqman probe for Chlamydia Trachomatis DNA. The amplified product was illuminated diagonally with a blue LED to excite the product just before imaging, and the LED was turned off when the image was captured to prevent quenching of the probe. The images were taken 10 seconds prior to the last extension step for each cycle using a DSLR camera. The experiments were run as a quartet for each three chambers made with different double-sided tape. The results showed that there were significant difference between the three tapes.

  2. Method of detecting genetic translocations identified with chromosomal abnormalities

    Energy Technology Data Exchange (ETDEWEB)

    Gray, Joe W. (Livermore, CA); Pinkel, Daniel (Walnut Creek, CA); Tkachuk, Douglas (Livermore, CA)

    2001-01-01

    Methods and compositions for staining based upon nucleic acid sequence that employ nucleic acid probes are provided. Said methods produce staining patterns that can be tailored for specific cytogenetic analyses. Said probes are appropriate for in situ hybridization and stain both interphase and metaphase chromosomal material with reliable signals. The nucleic acid probes are typically of a complexity greater than 50 kb, the complexity depending upon the cytogenetic application. Methods and reagents are provided for the detection of genetic rearrangements. Probes and test kits are provided for use in detecting genetic rearrangements, particularly for use in tumor cytogenetics, in the detection of disease related loci, specifically cancer, such as chronic myelogenous leukemia (CML) and for biological dosimetry. Methods and reagents are described for cytogenetic research, for the differentiation of cytogenetically similar but genetically different diseases, and for many prognostic and diagnostic applications.

  3. Incorporating privileged genetic information for fundus image based glaucoma detection.

    Science.gov (United States)

    Duan, Lixin; Xu, Yanwu; Li, Wen; Chen, Lin; Wing, Damon Wing Kee; Wong, Tien Yin; Liu, Jiang

    2014-01-01

    Visual features extracted from retinal fundus images have been increasingly used for glaucoma detection, as those images are generally easy to acquire. In recent years, genetic researchers have found that some single nucleic polymorphisms (SNPs) play important roles in the manifestation of glaucoma and also show superiority over fundus images for glaucoma detection. In this work, we propose to use the SNPs to form the so-called privileged information and deal with a practical problem where both fundus images and privileged genetic information exist for the training subjects, while the test objects only have fundus images. To solve this problem, we present an effective approach based on the learning using privileged information (LUPI) paradigm to train a predictive model for the image visual features. Extensive experiments demonstrate the usefulness of our approach in incorporating genetic information for fundus image based glaucoma detection.

  4. Chromosome-specific staining to detect genetic rearrangements

    Energy Technology Data Exchange (ETDEWEB)

    Gray, Joe W.; Pinkel, Daniel; Tkachuk, Douglas; Westbrook, Carol

    2013-04-09

    Methods and compositions for staining based upon nucleic acid sequence that employ nucleic acid probes are provided. Said methods produce staining patterns that can be tailored for specific cytogenetic analyzes. Said probes are appropriate for in situ hybridization and stain both interphase and metaphase chromosomal material with reliable signals. The nucleic acid probes are typically of a complexity greater than 50 kb, the complexity depending upon the cytogenetic application. Methods and reagents are provided for the detection of genetic rearrangements. Probes and test kits are provided for use in detecting genetic rearrangements, particularly for use in tumor cytogenetics, in the detection of disease related loci, specifically cancer, such as chronic myelogenous leukemia (CML) and for biological dosimetry. Methods and reagents are described for cytogenetic research, for the differentiation of cytogenetically similar but genetically different diseases, and for many prognostic and diagnostic applications.

  5. Method of detecting genetic deletions identified with chromosomal abnormalities

    Energy Technology Data Exchange (ETDEWEB)

    Gray, Joe W; Pinkel, Daniel; Tkachuk, Douglas

    2013-11-26

    Methods and compositions for staining based upon nucleic acid sequence that employ nucleic acid probes are provided. Said methods produce staining patterns that can be tailored for specific cytogenetic analyzes. Said probes are appropriate for in situ hybridization and stain both interphase and metaphase chromosomal material with reliable signals. The nucleic acids probes are typically of a complexity greater tha 50 kb, the complexity depending upon the cytogenetic application. Methods and reagents are provided for the detection of genetic rearrangements. Probes and test kits are provided for use in detecting genetic rearrangements, particlularly for use in tumor cytogenetics, in the detection of disease related loci, specifically cancer, such as chronic myelogenous leukemia (CML) and for biological dosimetry. Methods and reagents are described for cytogenetic research, for the differentiation of cytogenetically similar ut genetically different diseases, and for many prognostic and diagnostic applications.

  6. Method of detecting genetic deletions identified with chromosomal abnormalities

    Science.gov (United States)

    Gray, Joe W; Pinkel, Daniel; Tkachuk, Douglas

    2013-11-26

    Methods and compositions for staining based upon nucleic acid sequence that employ nucleic acid probes are provided. Said methods produce staining patterns that can be tailored for specific cytogenetic analyzes. Said probes are appropriate for in situ hybridization and stain both interphase and metaphase chromosomal material with reliable signals. The nucleic acids probes are typically of a complexity greater tha 50 kb, the complexity depending upon the cytogenetic application. Methods and reagents are provided for the detection of genetic rearrangements. Probes and test kits are provided for use in detecting genetic rearrangements, particlularly for use in tumor cytogenetics, in the detection of disease related loci, specifically cancer, such as chronic myelogenous leukemia (CML) and for biological dosimetry. Methods and reagents are described for cytogenetic research, for the differentiation of cytogenetically similar ut genetically different diseases, and for many prognostic and diagnostic applications.

  7. Chromosome-specific staining to detect genetic rearrangements

    Science.gov (United States)

    Gray, Joe W.; Pinkel, Daniel; Tkachuk, Douglas; Westbrook, Carol

    2013-04-09

    Methods and compositions for staining based upon nucleic acid sequence that employ nucleic acid probes are provided. Said methods produce staining patterns that can be tailored for specific cytogenetic analyzes. Said probes are appropriate for in situ hybridization and stain both interphase and metaphase chromosomal material with reliable signals. The nucleic acid probes are typically of a complexity greater than 50 kb, the complexity depending upon the cytogenetic application. Methods and reagents are provided for the detection of genetic rearrangements. Probes and test kits are provided for use in detecting genetic rearrangements, particularly for use in tumor cytogenetics, in the detection of disease related loci, specifically cancer, such as chronic myelogenous leukemia (CML) and for biological dosimetry. Methods and reagents are described for cytogenetic research, for the differentiation of cytogenetically similar but genetically different diseases, and for many prognostic and diagnostic applications.

  8. Deformability measurement of red blood cells using a microfluidic channel array and an air cavity in a driving syringe with high throughput and precise detection of subpopulations.

    Science.gov (United States)

    Kang, Yang Jun; Ha, Young-Ran; Lee, Sang-Joon

    2016-01-07

    Red blood cell (RBC) deformability has been considered a potential biomarker for monitoring pathological disorders. High throughput and detection of subpopulations in RBCs are essential in the measurement of RBC deformability. In this paper, we propose a new method to measure RBC deformability by evaluating temporal variations in the average velocity of blood flow and image intensity of successively clogged RBCs in the microfluidic channel array for specific time durations. In addition, to effectively detect differences in subpopulations of RBCs, an air compliance effect is employed by adding an air cavity into a disposable syringe. The syringe was equally filled with a blood sample (V(blood) = 0.3 mL, hematocrit = 50%) and air (V(air) = 0.3 mL). Owing to the air compliance effect, blood flow in the microfluidic device behaved transiently depending on the fluidic resistance in the microfluidic device. Based on the transient behaviors of blood flows, the deformability of RBCs is quantified by evaluating three representative parameters, namely, minimum value of the average velocity of blood flow, clogging index, and delivered blood volume. The proposed method was applied to measure the deformability of blood samples consisting of homogeneous RBCs fixed with four different concentrations of glutaraldehyde solution (0%-0.23%). The proposed method was also employed to evaluate the deformability of blood samples partially mixed with normal RBCs and hardened RBCs. Thereafter, the deformability of RBCs infected by human malaria parasite Plasmodium falciparum was measured. As a result, the three parameters significantly varied, depending on the degree of deformability. In addition, the deformability measurement of blood samples was successfully completed in a short time (∼10 min). Therefore, the proposed method has significant potential in deformability measurement of blood samples containing hematological diseases with high throughput and precise detection of

  9. [Recent development of microfluidic diagnostic technologies].

    Science.gov (United States)

    Li, Haifang; Zhang, Qianyun; Lin, Jin-Ming

    2011-04-01

    Microfluidic devices exhibit a great promising development in clinical diagnosis and disease screening due to their advantages of precise controlling of fluid flow, requirement of miniamount sample, rapid reaction speed and convenient integration. In this paper, the improvements of microfluidic diagnostic technologies in recent years are reviewed. The applications and developments of on-chip disease marker detection, microfluidic cell selection and cell drug metabolism, and diagnostic micro-devices are discussed.

  10. Detection of bacterial metabolites through dynamic acquisition from surface enhanced raman spectroscopy substrates integtrated in a centrifugal microfluidic platform

    DEFF Research Database (Denmark)

    Durucan, Onur; Morelli, Lidia; Schmidt, Michael Stenbæk

    2015-01-01

    In this work we present a novel technology that combines the advantages of centrifugal microfluidics with dynamic in-situ Surface Enhanced Raman Spectroscopy (SERS) sensing. Our technology is based on an automated readout system that allows on-line SERS acquisition on a rotating centrifugal micro...

  11. Theoretical microfluidics

    DEFF Research Database (Denmark)

    Bruus, Henrik

    in complexity, a proper theoretical understanding becomes increasingly important. The basic idea of the book is to provide a self-contained formulation of the theoretical framework of microfluidics, and at the same time give physical motivation and examples from lab-on-a-chip technology. After three chapters...

  12. Theoretical microfluidics

    DEFF Research Database (Denmark)

    Bruus, Henrik

    , complex flow patterns and acousto-fluidics, as well as the new fields of opto- and nano-fluidics. Throughout the book simple models with analytical solutions are presented to provide the student with a thorough physical understanding of order of magnitudes and various selected microfluidic phenomena...

  13. Microfluidic Imaging Flow Cytometry by Asymmetric-detection Time-stretch Optical Microscopy (ATOM).

    Science.gov (United States)

    Tang, Anson H L; Lai, Queenie T K; Chung, Bob M F; Lee, Kelvin C M; Mok, Aaron T Y; Yip, G K; Shum, Anderson H C; Wong, Kenneth K Y; Tsia, Kevin K

    2017-06-28

    Scaling the number of measurable parameters, which allows for multidimensional data analysis and thus higher-confidence statistical results, has been the main trend in the advanced development of flow cytometry. Notably, adding high-resolution imaging capabilities allows for the complex morphological analysis of cellular/sub-cellular structures. This is not possible with standard flow cytometers. However, it is valuable for advancing our knowledge of cellular functions and can benefit life science research, clinical diagnostics, and environmental monitoring. Incorporating imaging capabilities into flow cytometry compromises the assay throughput, primarily due to the limitations on speed and sensitivity in the camera technologies. To overcome this speed or throughput challenge facing imaging flow cytometry while preserving the image quality, asymmetric-detection time-stretch optical microscopy (ATOM) has been demonstrated to enable high-contrast, single-cell imaging with sub-cellular resolution, at an imaging throughput as high as 100,000 cells/s. Based on the imaging concept of conventional time-stretch imaging, which relies on all-optical image encoding and retrieval through the use of ultrafast broadband laser pulses, ATOM further advances imaging performance by enhancing the image contrast of unlabeled/unstained cells. This is achieved by accessing the phase-gradient information of the cells, which is spectrally encoded into single-shot broadband pulses. Hence, ATOM is particularly advantageous in high-throughput measurements of single-cell morphology and texture - information indicative of cell types, states, and even functions. Ultimately, this could become a powerful imaging flow cytometry platform for the biophysical phenotyping of cells, complementing the current state-of-the-art biochemical-marker-based cellular assay. This work describes a protocol to establish the key modules of an ATOM system (from optical frontend to data processing and visualization

  14. A microfluidic multiwell chip for enzyme-free detection of mRNA from few cells.

    Science.gov (United States)

    Haider, Michaela; Ji, Bozhi; Haselgrübler, Thomas; Sonnleitner, Alois; Aberger, Fritz; Hesse, Jan

    2016-12-15

    Isogenic cell populations possess heterogeneous gene expression patterns. Most methods for mRNA expression analysis start with the reverse transcription of mRNA into cDNA, a process that can introduce strong signal variations not related to the actual mRNA levels. Miniaturized lab-on-a-chip systems offer properties - e.g. low sample dilution, low contamination - that enable new reaction schemes for molecular analyses. To enable transcription-free mRNA expression analysis of few single cells, a one-step cell lysis, target labelling and hybridisation approach as well as a corresponding passive multiwell chip with a volume of 25.5 nL/well were developed. The method enabled the parallel analysis of up to 96 samples and 6 target genes per sample. Preceding light microscopy of the living cells allowed correlating mRNA levels and cell number. As a proof-of-principle, the pancreatic cancer cell line Panc-1 was investigated for expression heterogeneity of a reference gene plus 5 genes reported to be overexpressed in cancer stem cells (CSCs). A good correlation (r(51)=0.739, p<0.001; rs(51)=0.744, p<0.001) between the cell number per well and the number of detected reference gene mRNA confirmed the proper function of the device. Moreover, a heterogeneous expression of the CSC-associated target genes was found which matched well with reports on the presence of CSCs in the Panc-1 cell line.

  15. Label-free Detection of Influenza Viruses using a Reduced Graphene Oxide-based Electrochemical Immunosensor Integrated with a Microfluidic Platform

    Science.gov (United States)

    Singh, Renu; Hong, Seongkyeol; Jang, Jaesung

    2017-02-01

    Reduced graphene oxide (RGO) has recently gained considerable attention for use in electrochemical biosensing applications due to its outstanding conducting properties and large surface area. This report presents a novel microfluidic chip integrated with an RGO-based electrochemical immunosensor for label-free detection of an influenza virus, H1N1. Three microelectrodes were fabricated on a glass substrate using the photolithographic technique, and the working electrode was functionalized using RGO and monoclonal antibodies specific to the virus. These chips were integrated with polydimethylsiloxane microchannels. Structural and morphological characterizations were performed using X-ray photoelectron spectroscopy and scanning electron microscopy. Electrochemical studies revealed good selectivity and an enhanced detection limit of 0.5 PFU mL-1, where the chronoamperometric current increased linearly with H1N1 virus concentration within the range of 1 to 104 PFU mL-1 (R2 = 0.99). This microfluidic immunosensor can provide a promising platform for effective detection of biomolecules using minute samples.

  16. Label-free Detection of Influenza Viruses using a Reduced Graphene Oxide-based Electrochemical Immunosensor Integrated with a Microfluidic Platform

    Science.gov (United States)

    Singh, Renu; Hong, Seongkyeol; Jang, Jaesung

    2017-01-01

    Reduced graphene oxide (RGO) has recently gained considerable attention for use in electrochemical biosensing applications due to its outstanding conducting properties and large surface area. This report presents a novel microfluidic chip integrated with an RGO-based electrochemical immunosensor for label-free detection of an influenza virus, H1N1. Three microelectrodes were fabricated on a glass substrate using the photolithographic technique, and the working electrode was functionalized using RGO and monoclonal antibodies specific to the virus. These chips were integrated with polydimethylsiloxane microchannels. Structural and morphological characterizations were performed using X-ray photoelectron spectroscopy and scanning electron microscopy. Electrochemical studies revealed good selectivity and an enhanced detection limit of 0.5 PFU mL−1, where the chronoamperometric current increased linearly with H1N1 virus concentration within the range of 1 to 104 PFU mL−1 (R2 = 0.99). This microfluidic immunosensor can provide a promising platform for effective detection of biomolecules using minute samples. PMID:28198459

  17. Detection of ESKAPE Bacterial Pathogens at the Point of Care Using Isothermal DNA-Based Assays in a Portable Degas-Actuated Microfluidic Diagnostic Assay Platform.

    Science.gov (United States)

    Renner, Lars D; Zan, Jindong; Hu, Linda I; Martinez, Manuel; Resto, Pedro J; Siegel, Adam C; Torres, Clint; Hall, Sara B; Slezak, Tom R; Nguyen, Tuan H; Weibel, Douglas B

    2017-02-15

    An estimated 1.5 billion microbial infections occur globally each year and result in ∼4.6 million deaths. A technology gap associated with commercially available diagnostic tests in remote and underdeveloped regions prevents timely pathogen identification for effective antibiotic chemotherapies for infected patients. The result is a trial-and-error approach that is limited in effectiveness, increases risk for patients while contributing to antimicrobial drug resistance, and reduces the lifetime of antibiotics. This paper addresses this important diagnostic technology gap by describing a low-cost, portable, rapid, and easy-to-use microfluidic cartridge-based system for detecting the ESKAPE (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter spp.) bacterial pathogens that are most commonly associated with antibiotic resistance. The point-of-care molecular diagnostic system consists of a vacuum-degassed microfluidic cartridge preloaded with lyophilized recombinase polymerase amplification (RPA) assays and a small portable battery-powered electronic incubator/reader. The isothermal RPA assays detect the targeted ESKAPE pathogens with high sensitivity (e.g., a limit of detection of ∼10 nucleic acid molecules) that is comparable to that of current PCR-based assays, and they offer advantages in power consumption, engineering, and robustness, which are three critical elements required for the point-of-care setting.

  18. Integrating solid-state sensor and microfluidic devices for glucose, urea and creatinine detection based on enzyme-carrying alginate microbeads.

    Science.gov (United States)

    Lin, Yen-Heng; Wang, Shih-Hao; Wu, Min-Hsien; Pan, Tung-Ming; Lai, Chao-Sung; Luo, Ji-Dung; Chiou, Chiuan-Chian

    2013-05-15

    A solid-state sensor embedded microfluidic chip is demonstrated for the detection of glucose, urea and creatinine in human serum. In the presented device, magnetic powder-containing enzyme-carrying alginate microbeads are immobilized on the surface of an electrolyte-insulator-semiconductor (EIS) sensor by means of a step-like obstacle in the microchannel and an external magnetic force. The sample is injected into the microchannel and reacts with the enzyme contained within the alginate beads; prompting the release of hydrogen ions. The sample concentration is then evaluated by measuring the resulting change in the voltage signal of the EIS sensor. The reaction time and alginate bead size are optimized experimentally using a standard glucose solution. The experimental results show that the device has a detection range of 2-8mM, 1-16mM and 10(-2)-10mM for glucose, urea and creatinine, respectively. Furthermore, it is shown that the device is capable of sequentially measuring all three indicators in a human serum sample. Finally, it is shown that the measured values of the glucose, urea and creatinine concentrations obtained using the device deviate from those obtained using a commercial kit by just 5.17%, 6.22% and 13.53%, respectively. This method can be extended to sequentially measure multiple blood indicators in the sample chip by replacing different types of enzyme in alginate bead and can address the enzyme preservation issue in the microfluidic device. Overall, the results presented in this study indicate that the microfluidic chip has significant potential for blood monitoring in point-of-care applications.

  19. Multivariate Outlier Detection in Genetic Evaluation in Nordic Jersey Cattle

    DEFF Research Database (Denmark)

    Gao, Hongding; Madsen, Per; Pösö, Jukka

    A procedure was developed for detection of multivariate outliers based on an approximation for Mahanalobis Distance (MD) and was implemented in the Nordic Jersey population. Evaluations are carried out by Nordic Cattle Genetic Evaluation (NAV), who uses a 9 trait model for milk, protein and fat...

  20. Simple Plex(™) : A Novel Multi-Analyte, Automated Microfluidic Immunoassay Platform for the Detection of Human and Mouse Cytokines and Chemokines.

    Science.gov (United States)

    Aldo, Paulomi; Marusov, Gregory; Svancara, Danielle; David, James; Mor, Gil

    2016-06-01

    Quantitative measurement of proteins in bodily fluids or cellular preparations is critical for the evaluation of biomarkers or the study of complex cellular processes. While immunoassays are the most common quantitative approach used so far, they are not practical for the evaluation of multiple proteins. Microfluidic technology allows a fine spatial control in immobilizing proteins and biomolecules inside microchannels, eliminating cross-reactivity between competing analytes, and allowing rapid and sensitive detection of targeted antigens for multiple applications. We report the characterization and validation of the Simple Plex(™) platform for the detection and quantification of cytokines and chemokines from human and mouse samples. Cytokine and chemokine expression levels were determined using Simple Plex cartridges from ProteinSimple. Serum samples were obtained from the Yale Biorepository. Our data demonstrate an excellent correlation between the results obtained with Simple Plex and conventional immunoassays such as ELISA and Luminex. We describe the characterization and validation of Simple Plex, a novel multi-analyte, automated microfluidic platform that allows the evaluation of cytokines and chemokines from human and mice biological samples. Simple Plex showed significant advantages over traditional approaches in terms of low sample volume requirements, sensitivity and dynamic range, coefficient of variation, and reproducibility. © 2016 The Authors. American Journal of Reproductive Immunology Published by John Wiley & Sons Ltd.

  1. Microfluidic Integration of a Cloth-Based Hybridization Array System (CHAS) for Rapid, Colorimetric Detection of Enterohemorrhagic Escherichia coli (EHEC) Using an Articulated, Centrifugal Platform.

    Science.gov (United States)

    Geissler, Matthias; Clime, Liviu; Hoa, Xuyen D; Morton, Keith J; Hébert, Harold; Poncelet, Lucas; Mounier, Maxence; Deschênes, Mylène; Gauthier, Martine E; Huszczynski, George; Corneau, Nathalie; Blais, Burton W; Veres, Teodor

    2015-10-20

    We describe the translation of a cloth-based hybridization array system (CHAS), a colorimetric DNA detection method that is used by food inspection laboratories for colony screening of pathogenic agents, onto a microfluidic chip format. We also introduce an articulated centrifugal platform with a novel fluid manipulation concept based on changes in the orientation of the chip with respect to the centrifugal force field to time the passage of multiple components required for the process. The platform features two movable and motorized carriers that can be reoriented on demand between 0 and 360° during stage rotation. Articulation of the chip can be used to trigger on-the-fly fluid dispensing through independently addressable siphon structures or to relocate solutions against the centrifugal force field, making them newly accessible for downstream transfer. With the microfluidic CHAS, we achieved significant reduction in the size of the cloth substrate as well as the volume of reagents and wash solutions. Both the chip design and the operational protocol were optimized to perform the entire process in a reliable, fully automated fashion. A demonstration with PCR-amplified genomic DNA confirms on-chip detection and identification of Escherichia coli O157:H7 from colony isolates in a colorimetric multiplex assay using rfbO157, fliCH7, vt1, and vt2 genes.

  2. Safety assessment and detection methods of genetically modified organisms.

    Science.gov (United States)

    Xu, Rong; Zheng, Zhe; Jiao, Guanglian

    2014-01-01

    Genetically modified organisms (GMOs), are gaining importance in agriculture as well as the production of food and feed. Along with the development of GMOs, health and food safety concerns have been raised. These concerns for these new GMOs make it necessary to set up strict system on food safety assessment of GMOs. The food safety assessment of GMOs, current development status of safety and precise transgenic technologies and GMOs detection have been discussed in this review. The recent patents about GMOs and their detection methods are also reviewed. This review can provide elementary introduction on how to assess and detect GMOs.

  3. Genetics and early detection in idiopathic pulmonary fibrosis.

    Science.gov (United States)

    Putman, Rachel K; Rosas, Ivan O; Hunninghake, Gary M

    2014-04-01

    Genetic studies hold promise in helping to identify patients with early idiopathic pulmonary fibrosis (IPF). Recent studies using chest computed tomograms (CTs) in smokers and in the general population have demonstrated that imaging abnormalities suggestive of an early stage of pulmonary fibrosis are not uncommon and are associated with respiratory symptoms, physical examination abnormalities, and physiologic decrements expected, but less severe than those noted in patients with IPF. Similarly, recent genetic studies have demonstrated strong and replicable associations between a common promoter polymorphism in the mucin 5B gene (MUC5B) and both IPF and the presence of abnormal imaging findings in the general population. Despite these findings, it is important to note that the definition of early-stage IPF remains unclear, limited data exist to definitively connect abnormal imaging findings to IPF, and genetic studies assessing early-stage pulmonary fibrosis remain in their infancy. In this perspective we provide updated information on interstitial lung abnormalities and their connection to IPF. We summarize information on the genetics of pulmonary fibrosis by focusing on the recent genetic findings of MUC5B. Finally, we discuss the implications of these findings and suggest a roadmap for the use of genetics in the detection of early IPF.

  4. Microfluidic Device

    Science.gov (United States)

    Tai, Yu-Chong (Inventor); Zheng, Siyang (Inventor); Lin, Jeffrey Chun-Hui (Inventor); Kasdan, Harvey L. (Inventor)

    2017-01-01

    Described herein are particular embodiments relating to a microfluidic device that may be utilized for cell sensing, counting, and/or sorting. Particular aspects relate to a microfabricated device that is capable of differentiating single cell types from dense cell populations. One particular embodiment relates a device and methods of using the same for sensing, counting, and/or sorting leukocytes from whole, undiluted blood samples.

  5. Current perspectives on genetically modified crops and detection methods.

    Science.gov (United States)

    Kamle, Madhu; Kumar, Pradeep; Patra, Jayanta Kumar; Bajpai, Vivek K

    2017-07-01

    Genetically modified (GM) crops are the fastest adopted commodities in the agribiotech industry. This market penetration should provide a sustainable basis for ensuring food supply for growing global populations. The successful completion of two decades of commercial GM crop production (1996-2015) is underscored by the increasing rate of adoption of genetic engineering technology by farmers worldwide. With the advent of introduction of multiple traits stacked together in GM crops for combined herbicide tolerance, insect resistance, drought tolerance or disease resistance, the requirement of reliable and sensitive detection methods for tracing and labeling genetically modified organisms in the food/feed chain has become increasingly important. In addition, several countries have established threshold levels for GM content which trigger legally binding labeling schemes. The labeling of GM crops is mandatory in many countries (such as China, EU, Russia, Australia, New Zealand, Brazil, Israel, Saudi Arabia, Korea, Chile, Philippines, Indonesia, Thailand), whereas in Canada, Hong Kong, USA, South Africa, and Argentina voluntary labeling schemes operate. The rapid adoption of GM crops has increased controversies, and mitigating these issues pertaining to the implementation of effective regulatory measures for the detection of GM crops is essential. DNA-based detection methods have been successfully employed, while the whole genome sequencing using next-generation sequencing (NGS) technologies provides an advanced means for detecting genetically modified organisms and foods/feeds in GM crops. This review article describes the current status of GM crop commercialization and discusses the benefits and shortcomings of common and advanced detection systems for GMs in foods and animal feeds.

  6. Microfluidics' great promise for Biology - Microfluidics as a new engine for the molecular sciences

    KAUST Repository

    Kodzius, Rimantas

    2010-06-04

    History of the Life Sciences Origins of life Discoveries and instrumentation The power of genetic variation Diagnostics based on DNA/ protein variation Genomic scanning providers DNA sequencing companies Microfluidics story Commercial products available P

  7. Gold nanoparticles-coated magnetic microspheres as affinity matrix for detection of hemoglobin A1c in blood by microfluidic immunoassay.

    Science.gov (United States)

    Chen, Shao-Peng; Yu, Xiao-Dong; Xu, Jing-Juan; Chen, Hong-Yuan

    2011-08-15

    A novel microfluidic immunoassay system for specific detection of hemoglobin A1c (HbA1c) was developed based on a three-component shell/shell/core structured magnetic nanocomposite Au/chitosan/Fe(3)O(4), which was synthesized with easy handling feature of Fe(3)O(4) by magnet, high affinity for gold nanoparticles of chitosan and good immobilization ability for anti-human hemoglobin-A1c antibody (HbA1c mAb) of assembled colloidal gold nanoparticles. The resulting HbA1c mAb/Au/chitosan/Fe(3)O(4) magnetic nanoparticles were then introduced into microfluidic devices coupled with a gold nanoband microelectrode as electrochemical detector. After that, three-step rapid immunoreactions were carried out in the sequence of HbA1c, anti-human hemoglobin antibodies (Hb mAb) and the secondary alkaline phosphatase (AP)-conjugated antibody within 20 min. The current response of 1-naphtol obtained from the reaction between the secondary AP-conjugated antibody and 1-naphthyl phosphate (1-NP) increased proportionally to the HbA1c concentration. Under optimized electrophoresis and detection conditions, HbA1c responded linearly in the concentration of 0.05-1.5 μg mL(-1), with the detection limit of 0.025 μg mL(-1). This system was successfully employed for detection of HbA1c in blood with good accuracy and renewable ability. The proposed method proved its potential use in clinical immunoassay of HbA1c.

  8. An Adaptive Immune Genetic Algorithm for Edge Detection

    Science.gov (United States)

    Li, Ying; Bai, Bendu; Zhang, Yanning

    An adaptive immune genetic algorithm (AIGA) based on cost minimization technique method for edge detection is proposed. The proposed AIGA recommends the use of adaptive probabilities of crossover, mutation and immune operation, and a geometric annealing schedule in immune operator to realize the twin goals of maintaining diversity in the population and sustaining the fast convergence rate in solving the complex problems such as edge detection. Furthermore, AIGA can effectively exploit some prior knowledge and information of the local edge structure in the edge image to make vaccines, which results in much better local search ability of AIGA than that of the canonical genetic algorithm. Experimental results on gray-scale images show the proposed algorithm perform well in terms of quality of the final edge image, rate of convergence and robustness to noise.

  9. Detection methods and performance criteria for genetically modified organisms.

    Science.gov (United States)

    Bertheau, Yves; Diolez, Annick; Kobilinsky, André; Magin, Kimberly

    2002-01-01

    Detection methods for genetically modified organisms (GMOs) are necessary for many applications, from seed purity assessment to compliance of food labeling in several countries. Numerous analytical methods are currently used or under development to support these needs. The currently used methods are bioassays and protein- and DNA-based detection protocols. To avoid discrepancy of results between such largely different methods and, for instance, the potential resulting legal actions, compatibility of the methods is urgently needed. Performance criteria of methods allow evaluation against a common standard. The more-common performance criteria for detection methods are precision, accuracy, sensitivity, and specificity, which together specifically address other terms used to describe the performance of a method, such as applicability, selectivity, calibration, trueness, precision, recovery, operating range, limit of quantitation, limit of detection, and ruggedness. Performance criteria should provide objective tools to accept or reject specific methods, to validate them, to ensure compatibility between validated methods, and be used on a routine basis to reject data outside an acceptable range of variability. When selecting a method of detection, it is also important to consider its applicability, its field of applications, and its limitations, by including factors such as its ability to detect the target analyte in a given matrix, the duration of the analyses, its cost effectiveness, and the necessary sample sizes for testing. Thus, the current GMO detection methods should be evaluated against a common set of performance criteria.

  10. A wireless point-of-care testing system for the detection of neuron-specific enolase with microfluidic paper-based analytical devices.

    Science.gov (United States)

    Fan, Yan; Liu, Juntao; Wang, Yang; Luo, Jinping; Xu, Huiren; Xu, Shengwei; Cai, Xinxia

    2017-09-15

    Neuron-specific enolase (NSE) had clinical significance on diagnosis, staging, monitoring effect and judging prognosis of small cell lung cancer. Thus, there had a growing demand for the on-site testing of NSE. Here, a wireless point-of-care testing (POCT) system with electrochemical measurement for NSE detection was developed and verified. The wireless POCT system consisted of microfluidic paper-based analytical devices (μPADs), electrochemical detector and Android's smartphone. Differential pulse voltammetry (DPV) measurement was adopted by means of electrochemical detector which including a potentiostat and current-to-voltage converter. μPADs were modified with nanocomposites synthesized by Amino functional graphene, thionine and gold nanoparticles (NH2-G/Thi/AuNPs) as immunosensors for NSE detection. Combined with μPADs, the performance of the wireless POCT system was evaluated. The peak currents showed good linear relationship of the logarithm of NSE concentration ranging from 1 to 500ngmL(-1) with the limit of detection (LOD) of 10pgmL(-1). The detection results were automatically stored in EEPROM memory and could be displayed on Android's smartphone through Bluetooth in real time. The detection results were comparable to those measured by a commercial electrochemical workstation. The wireless POCT system had the potential for on-site testing of other tumor markers. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. Perspectives on genetically modified crops and food detection

    Directory of Open Access Journals (Sweden)

    Chih-Hui Lin

    2016-01-01

    Full Text Available Genetically modified (GM crops are a major product of the global food industry. From 1996 to 2014, 357 GM crops were approved and the global value of the GM crop market reached 35% of the global commercial seed market in 2014. However, the rapid growth of the GM crop-based industry has also created controversies in many regions, including the European Union, Egypt, and Taiwan. The effective detection and regulation of GM crops/foods are necessary to reduce the impact of these controversies. In this review, the status of GM crops and the technology for their detection are discussed. As the primary gap in GM crop regulation exists in the application of detection technology to field regulation, efforts should be made to develop an integrated, standardized, and high-throughput GM crop detection system. We propose the development of an integrated GM crop detection system, to be used in combination with a standardized international database, a decision support system, high-throughput DNA analysis, and automated sample processing. By integrating these technologies, we hope that the proposed GM crop detection system will provide a method to facilitate comprehensive GM crop regulation.

  12. Electrochemiluminescence-PCR detection of genetically modified organisms

    Science.gov (United States)

    Liu, Jinfeng; Xing, Da; Shen, Xingyan; Zhu, Debin

    2005-01-01

    The detection methods for genetically modified (GM) components in foods have been developed recently. But many of them are complicated and time-consuming; some of them need to use the carcinogenic substance, and can"t avoid false-positive results. In this study, an electrochemiluminescence polymerase chain reaction (ECL-PCR) method for detection GM tobaccos is proposed. The Cauliflower mosaic virus 35S (CaMV35S) promoter was amplified by PCR, Then hybridized with a Ru(bpy)32+ (TBR)-labeled and a biotinylated probe. The hybridization products were captured onto streptavidin-coated paramagnetic beads, and detected by measuring the electrochemiluminescence (ECL) signal of the TBR label. Whether the tobaccos contain GM components was discriminated by detecting the ECL signal of CaMV35S promoter. The experiment results show that the detection limit for CaMV35S promoter is 100 fmol, and the GM components can be clearly identified in GM tobaccos. The ECL-PCR method provide a new means in GMOs detection due to its safety, simplicity and high efficiency.

  13. Manipulation of microfluidic droplets by electrorheological fluid

    KAUST Repository

    Zhang, Menying

    2009-09-01

    Microfluidics, especially droplet microfluidics, attracts more and more researchers from diverse fields, because it requires fewer materials and less time, produces less waste and has the potential of highly integrated and computer-controlled reaction processes for chemistry and biology. Electrorheological fluid, especially giant electrorheological fluid (GERF), which is considered as a kind of smart material, has been applied to the microfluidic systems to achieve active and precise control of fluid by electrical signal. In this review article, we will introduce recent results of microfluidic droplet manipulation, GERF and some pertinent achievements by introducing GERF into microfluidic system: digital generation, manipulation of "smart droplets" and droplet manipulation by GERF. Once it is combined with real-time detection, integrated chip with multiple functions can be realized. © 2009 Wiley-VCH Verlag GmbH & Co. KGaA.

  14. Microfluidics for food, agriculture and biosystems industries.

    Science.gov (United States)

    Neethirajan, Suresh; Kobayashi, Isao; Nakajima, Mitsutoshi; Wu, Dan; Nandagopal, Saravanan; Lin, Francis

    2011-05-07

    Microfluidics, a rapidly emerging enabling technology has the potential to revolutionize food, agriculture and biosystems industries. Examples of potential applications of microfluidics in food industry include nano-particle encapsulation of fish oil, monitoring pathogens and toxins in food and water supplies, micro-nano-filtration for improving food quality, detection of antibiotics in dairy food products, and generation of novel food structures. In addition, microfluidics enables applications in agriculture and animal sciences such as nutrients monitoring and plant cells sorting for improving crop quality and production, effective delivery of biopesticides, simplified in vitro fertilization for animal breeding, animal health monitoring, vaccination and therapeutics. Lastly, microfluidics provides new approaches for bioenergy research. This paper synthesizes information of selected microfluidics-based applications for food, agriculture and biosystems industries. © The Royal Society of Chemistry 2011

  15. Manipulation of microfluidic droplets by electrorheological fluid.

    Science.gov (United States)

    Zhang, Menying; Gong, Xiuqing; Wen, Weijia

    2009-09-01

    Microfluidics, especially droplet microfluidics, attracts more and more researchers from diverse fields, because it requires fewer materials and less time, produces less waste and has the potential of highly integrated and computer-controlled reaction processes for chemistry and biology. Electrorheological fluid, especially giant electrorheological fluid (GERF), which is considered as a kind of smart material, has been applied to the microfluidic systems to achieve active and precise control of fluid by electrical signal. In this review article, we will introduce recent results of microfluidic droplet manipulation, GERF and some pertinent achievements by introducing GERF into microfluidic system: digital generation, manipulation of "smart droplets" and droplet manipulation by GERF. Once it is combined with real-time detection, integrated chip with multiple functions can be realized.

  16. CCD Detection System for Multi-channel Microfluidic Electrophoresis Chip%多通道微流控电泳芯片CCD检测系统

    Institute of Scientific and Technical Information of China (English)

    吕宏峰; 闫卫平; 朱杰英

    2012-01-01

    针对微流控电泳芯片检测系统微型化、集成化的要求,分析了传统电泳芯片检测系统的优势和不足,提出一种以FPGA芯片为控制器的CCD多通道微流控电泳芯片检测系统.利用FPGA/NiosⅡ嵌入式系统解决方案,以EP2C8Q208芯片为核心,设计了CCD驱动及外围硬件电路.通过上位机软件进行数据处理,实现了荧光图谱的同步显示.实验结果表明:该系统能同时检测多通道微流控电泳芯片中各通道不同的荧光信号强度,具有较高的灵敏度和信噪比,对罗丹明B样品的最低检测浓度为1.0×10-6mol/L,能够满足多通道微流控电泳芯片检测的要求.%Based on the requirement with detection system for microfluidic electrophoresis chip in terms of miniaturization, integration , the traditional equipment advantage and the shortage was analyzed. A CCD detection system for multi-channel microfluidic electrophoresis chip used FPGA as the main logic controller was proposed. FPGA/Nios Ⅱ embedded system was adopted into the project which designed the CCD driving and other periphery circuit with the EP2C8Q208 chip as its core. The data was transferred to the PC. Then the fluorescence spectrum was shown by the software. The result indicated that the system can detect the different fluorescence intensity in the micirofluidic chip at the same time. The minimum detecting limit is 1.0 × 10-6 mol/L (Rhodamine B). This detecting system has several characteristics such as high signal-noise ratio and high sensitivity, which can meet the demand of detection of the multi-channel micirofluidic electrophoresis chip.

  17. Microfluidic Technologies for Synthetic Biology

    Directory of Open Access Journals (Sweden)

    Sung Kuk Lee

    2011-06-01

    Full Text Available Microfluidic technologies have shown powerful abilities for reducing cost, time, and labor, and at the same time, for increasing accuracy, throughput, and performance in the analysis of biological and biochemical samples compared with the conventional, macroscale instruments. Synthetic biology is an emerging field of biology and has drawn much attraction due to its potential to create novel, functional biological parts and systems for special purposes. Since it is believed that the development of synthetic biology can be accelerated through the use of microfluidic technology, in this review work we focus our discussion on the latest microfluidic technologies that can provide unprecedented means in synthetic biology for dynamic profiling of gene expression/regulation with high resolution, highly sensitive on-chip and off-chip detection of metabolites, and whole-cell analysis.

  18. Microfluidic Scintillation Detectors

    CERN Multimedia

    Microfluidic scintillation detectors are devices of recent introduction for the detection of high energy particles, developed within the EP-DT group at CERN. Most of the interest for such technology comes from the use of liquid scintillators, which entails the possibility of changing the active material in the detector, leading to an increased radiation resistance. This feature, together with the high spatial resolution and low thickness deriving from the microfabrication techniques used to manufacture such devices, is desirable not only in instrumentation for high energy physics experiments but also in medical detectors such as beam monitors for hadron therapy.

  19. Multivariate Outlier Detection in Genetic Evaluation in Nordic Jersey Cattle

    DEFF Research Database (Denmark)

    Gao, Hongding; Madsen, Per; Pösö, Jukka

    A procedure was developed for detection of multivariate outliers based on an approximation for Mahanalobis Distance (MD) and was implemented in the Nordic Jersey population. Evaluations are carried out by Nordic Cattle Genetic Evaluation (NAV), who uses a 9 trait model for milk, protein and fat...... means and co-variance matrix for the actual PY, lactation and DIM. Accuracy of EBV’s is improved for animals having extreme outlier record(s) deleted compared to EBV’s based on data not filtered for MD....

  20. Detecting structural breaks in time series via genetic algorithms

    DEFF Research Database (Denmark)

    Doerr, Benjamin; Fischer, Paul; Hilbert, Astrid

    2016-01-01

    Detecting structural breaks is an essential task for the statistical analysis of time series, for example, for fitting parametric models to it. In short, structural breaks are points in time at which the behaviour of the time series substantially changes. Typically, no solid background knowledge...... and mutation operations for this problem, we conduct extensive experiments to determine good choices for the parameters and operators of the genetic algorithm. One surprising observation is that use of uniform and one-point crossover together gave significantly better results than using either crossover...

  1. Lytic enzymes as selectivity means for label-free, microfluidic and impedimetric detection of whole-cell bacteria using ALD-Al2O3 passivated microelectrodes.

    Science.gov (United States)

    Couniot, N; Vanzieleghem, T; Rasson, J; Van Overstraeten-Schlögel, N; Poncelet, O; Mahillon, J; Francis, L A; Flandre, D

    2015-05-15

    Point-of-care (PoC) diagnostics for bacterial detection offer tremendous prospects for public health care improvement. However, such tools require the complex combination of the following performances: rapidity, selectivity, sensitivity, miniaturization and affordability. To meet these specifications, this paper presents a new selectivity method involving lysostaphin together with a CMOS-compatible impedance sensor for genus-specific bacterial detection. The method enables the sample matrix to be directly flown on the polydopamine-covered sensor surface without any pre-treatment, and considerably reduces the background noise. Experimental proof-of-concept, explored by simulations and confirmed through a setup combining simultaneous optical and electrical real-time monitoring, illustrates the selective and capacitive detection of Staphylococcus epidermidis in synthetic urine also containing Enterococcus faecium. While providing capabilities for miniaturization and system integration thanks to CMOS compatibility, the sensors show a detection limit of ca. 10(8) (CFU/mL).min in a 1.5 μL microfluidic chamber with an additional setup time of 50 min. The potentials, advantages and limitations of the method are also discussed. Copyright © 2014 Elsevier B.V. All rights reserved.

  2. Microfluidic electrochemical reactors

    Science.gov (United States)

    Nuzzo, Ralph G [Champaign, IL; Mitrovski, Svetlana M [Urbana, IL

    2011-03-22

    A microfluidic electrochemical reactor includes an electrode and one or more microfluidic channels on the electrode, where the microfluidic channels are covered with a membrane containing a gas permeable polymer. The distance between the electrode and the membrane is less than 500 micrometers. The microfluidic electrochemical reactor can provide for increased reaction rates in electrochemical reactions using a gaseous reactant, as compared to conventional electrochemical cells. Microfluidic electrochemical reactors can be incorporated into devices for applications such as fuel cells, electrochemical analysis, microfluidic actuation, pH gradient formation.

  3. Pollen genetic markers for detection of mutagens in the environment

    Energy Technology Data Exchange (ETDEWEB)

    Nilan, R.A.; Rosichan, J.L.; Arenaz, P.; Hodgdon, A.L.; Kleinhofs, A.

    1980-01-01

    To utilize and exploit pollen for in situ mutagen monitoring, screening and toxicology, the range of genetic traits in pollen must be identified and analyzed. To be useful for the development of mutagen detection systems proteins should be: (1) activity stainable or immunologically identifiable in the pollen, (2) the products of one to three loci; and (3) gametophytic and nuclear in origin. Several proteins, including alcohol dehydrogenase in maize, which meet these criteria are discussed. The waxy locus in barley and maize which controls starch deposition for pollen screening and mutant detection. Thirty waxy mutant lines, induced by sodium azide and gamma-rays are characterized for spontaneous and induced reversion frequencies, allelism, karyotype, amylose content, and UDPglucose glucosyltransferase (waxy gene product) activity. Twelve mutant alleles are being mapped by recombinant frequencies.

  4. A novel genetic programming approach for epileptic seizure detection.

    Science.gov (United States)

    Bhardwaj, Arpit; Tiwari, Aruna; Krishna, Ramesh; Varma, Vishaal

    2016-02-01

    The human brain is a delicate mix of neurons (brain cells), electrical impulses and chemicals, known as neurotransmitters. Any damage has the potential to disrupt the workings of the brain and cause seizures. These epileptic seizures are the manifestations of epilepsy. The electroencephalograph (EEG) signals register average neuronal activity from the cerebral cortex and label changes in activity over large areas. A detailed analysis of these electroencephalograph (EEG) signals provides valuable insights into the mechanisms instigating epileptic disorders. Moreover, the detection of interictal spikes and epileptic seizures in an EEG signal plays an important role in the diagnosis of epilepsy. Automatic seizure detection methods are required, as these epileptic seizures are volatile and unpredictable. This paper deals with an automated detection of epileptic seizures in EEG signals using empirical mode decomposition (EMD) for feature extraction and proposes a novel genetic programming (GP) approach for classifying the EEG signals. Improvements in the standard GP approach are made using a Constructive Genetic Programming (CGP) in which constructive crossover and constructive subtree mutation operators are introduced. A hill climbing search is integrated in crossover and mutation operators to remove the destructive nature of these operators. A new concept of selecting the Globally Prime offspring is also presented to select the best fitness offspring generated during crossover. To decrease the time complexity of GP, a new dynamic fitness value computation (DFVC) is employed to increase the computational speed. We conducted five different sets of experiments to evaluate the performance of the proposed model in the classification of different mixtures of normal, interictal and ictal signals, and the accuracies achieved are outstandingly high. The experimental results are compared with the existing methods on same datasets, and these results affirm the potential use of

  5. Genetically engineered microorganisms for the detection of explosives' residues

    Directory of Open Access Journals (Sweden)

    Benjamin eShemer

    2015-10-01

    Full Text Available The manufacture and use of explosives throughout the past century has resulted in the extensive pollution of soils and groundwater, and the widespread interment of landmines imposes a major humanitarian risk and prevents civil development of large areas. As most current landmine detection technologies require actual presence at the surveyed areas, thus posing a significant risk to personnel, diverse research efforts are aimed at the development of remote detection solutions. One possible means proposed to fulfill this objective is the use of microbial bioreporters: genetically engineered microorganisms tailored to generate an optical signal in the presence of explosives’ vapors. The use of such sensor bacteria will allow to pinpoint the locations of explosive devices in a minefield. While no study has yet resulted in a commercially operational system, significant progress has been made in the design and construction of explosives-sensing bacterial strains. In this article we review the attempts to construct microbial bioreporters for the detection of explosives, and analyze the steps that need to be undertaken for this strategy to be applicable for landmine detection.

  6. Genetically engineered microorganisms for the detection of explosives’ residues

    Science.gov (United States)

    Shemer, Benjamin; Palevsky, Noa; Yagur-Kroll, Sharon; Belkin, Shimshon

    2015-01-01

    The manufacture and use of explosives throughout the past century has resulted in the extensive pollution of soils and groundwater, and the widespread interment of landmines imposes a major humanitarian risk and prevents civil development of large areas. As most current landmine detection technologies require actual presence at the surveyed areas, thus posing a significant risk to personnel, diverse research efforts are aimed at the development of remote detection solutions. One possible means proposed to fulfill this objective is the use of microbial bioreporters: genetically engineered microorganisms “tailored” to generate an optical signal in the presence of explosives’ vapors. The use of such sensor bacteria will allow to pinpoint the locations of explosive devices in a minefield. While no study has yet resulted in a commercially operational system, significant progress has been made in the design and construction of explosives-sensing bacterial strains. In this article we review the attempts to construct microbial bioreporters for the detection of explosives, and analyze the steps that need to be undertaken for this strategy to be applicable for landmine detection. PMID:26579085

  7. Improved Genetic Algorithm Optimization for Forward Vehicle Detection Problems

    Directory of Open Access Journals (Sweden)

    Longhui Gang

    2015-07-01

    Full Text Available Automated forward vehicle detection is an integral component of many advanced driver-assistance systems. The method based on multi-visual information fusion, with its exclusive advantages, has become one of the important topics in this research field. During the whole detection process, there are two key points that should to be resolved. One is to find the robust features for identification and the other is to apply an efficient algorithm for training the model designed with multi-information. This paper presents an adaptive SVM (Support Vector Machine model to detect vehicle with range estimation using an on-board camera. Due to the extrinsic factors such as shadows and illumination, we pay more attention to enhancing the system with several robust features extracted from a real driving environment. Then, with the introduction of an improved genetic algorithm, the features are fused efficiently by the proposed SVM model. In order to apply the model in the forward collision warning system, longitudinal distance information is provided simultaneously. The proposed method is successfully implemented on a test car and evaluation experimental results show reliability in terms of both the detection rate and potential effectiveness in a real-driving environment.

  8. Integrated ZnO nanoparticles on paper-based microfluidic: toward efficient analytical device for glucose detection based on impedance and FTIR measurement

    Science.gov (United States)

    Yuwono, Rio Akbar; Izdiharruddin, Mokhammad Fahmi; Wahyuono, Ruri Agung

    2016-11-01

    Microfluidic paper-based analytical devices decorated with ZnO nanospherical (nanoSPs) aggregates (ZnO-μPAD) for glucose detection have been fabricated. ZnO nanoSPs were prepared by wet chemical synthesis and integrated on the optimized geometry of ZnO-μPAD has 0.2 and 0.4 mm of channel width and length, respectively. Glucose detection measurements were based on electrochemical and infrared transmission measurements. The glucose concentrations were adjusted as 5, 6.5, and 9 mmol, i.e. typical glucose level for normal, pre-diabetes and diabetes, in a mixture of ringer lactate as simulated biological fluid and red blood cells. ZnO nanoSPs in this study possess an average aggregate size of 160 nm formed by clustered 18 nm crystallite size and ordered porous matrix as well as a surface area of 15 m2·g-1.The separation process of the glucose sample on ZnO-μPAD requires approximately 45 s. The glucose detection results show that both electrochemical-based and FTIR-based measurements perform a linear measurement system (R2 of 0.81 to 0.99) with a relatively high sensitivity. A linearly decreasing impedance spanning from 2.2 - 0.6 Ohm and linearly increasing ΔIR transmission spanning from 3 - 19% are obtained for glucose level ranging from 5 - 9 mmol.

  9. Ligase detection reaction for the analysis of point mutations using free-solution conjugate electrophoresis in a polymer microfluidic device.

    Science.gov (United States)

    Sinville, Rondedrick; Coyne, Jennifer; Meagher, Robert J; Cheng, Yu-Wei; Barany, Francis; Barron, Annelise; Soper, Steven A

    2008-12-01

    We have developed a new method for the analysis of low abundant point mutations in genomic DNA using a combination of an allele-specific ligase detection reaction (LDR) with free-solution conjugate electrophoresis (FSCE) to generate and analyze the genetic products. FSCE eliminates the need for a polymer sieving matrix by conjugating chemically synthesized polyamide "drag-tags" onto the LDR primers. The additional drag of the charge-neutral drag-tag breaks the linear scaling of the charge-to-friction ratio of DNA and enables size-based separations of DNA in free solution using electrophoresis with no sieving matrix. We successfully demonstrate the conjugation of polyamide drag-tags onto a set of four LDR primers designed to probe the K-ras oncogene for mutations highly associated with colorectal cancer, the simultaneous generation of fluorescently labeled LDR/drag-tag conjugate (LDR-dt) products in a multiplexed, single-tube format with mutant:WT ratios as low as 1:100, respectively, and the single-base, high-resolution separation of all four LDR-dt products. Separations were conducted in free solution with no polymer network using both a commercial capillary array electrophoresis (CAE) system and a PMMA microchip replicated via hot-embossing with only a Tris-based running buffer containing additives to suppress the EOF. Typical analysis times for LDR-dt were 11 min using the CAE system and as low as 85 s for the PMMA microchips. With resolution comparable to traditional gel-based CAE, FSCE along with microchip electrophoresis decreased the separation time by more than a factor of 40.

  10. PREFACE: Nano- and microfluidics Nano- and microfluidics

    Science.gov (United States)

    Jacobs, Karin

    2011-05-01

    , Uhlmann et al and articles to be published in a later issue by Bäumchen and Jacobs, Walz et al). Moreover, simulations accounted for these new phenomena (see articles in this issue by Leonforte et al, Hyväaluoma et al, Varnik et al, Chelakkot et al, Litvinov et al and the article to be published in a later issue by Boettcher et al), since commercial software packages typically override these special yet fundamentally new conditions. For future applications, the know-how can be used, for instance, to manipulate particles or molecules in microfluidic systems (see articles in this issue by Nottebrock et al, Straube, Uhlmann et al and the article to be published in a later issue by Boettcher et al). The articles have been divided into four subsections: 'Probing the boundary condition', 'Flow over or in special geometries', 'Soft objects in fluid flow' and 'Manipulating flow'. Many articles, however, cover more than only one aspect and could easily be listed under one of the other subsections. Three articles, two listed in the section 'Probing the boundary condition' and one listed in 'Manipulating flow', could not be included and will be published in a later issue (Bäumchen and Jacobs, Walz et al, Boettcher et al). The collection of studies gives a comprehensive overview of what has been achieved to 'bridge the gap between molecular motion and continuum flow', which was the mission of the programme and which will now form a sound platform for continuative studies. References [1] Bowtell D D 1999 Nature Genet. 21 25 [2] Lion N et al 2003 Electrophoresis 24 3533 [3] Weston A D and Hood L 2004 J. Proteome Res. 3 179 [4] Li D 2004 Microfluidics Nanofluidics 1 1 Nano- and microfluidics contents Impact of slippage on the morphology and stability of a dewetting rim Andreas Münch and Barbara Wagner Nanoscale discontinuities at the boundary of flowing liquids: a look into structure Max Wolff, Philipp Gutfreund, Adrian Rühm, Bulent Akgun and Hartmut Zabel Capillary waves of

  11. Microfluidic Systems for Pathogen Sensing: A Review

    Directory of Open Access Journals (Sweden)

    Peter Ertl

    2009-06-01

    Full Text Available Rapid pathogen sensing remains a pressing issue today since conventional identification methodsare tedious, cost intensive and time consuming, typically requiring from 48 to 72 h. In turn, chip based technologies, such as microarrays and microfluidic biochips, offer real alternatives capable of filling this technological gap. In particular microfluidic biochips make the development of fast, sensitive and portable diagnostic tools possible, thus promising rapid and accurate detection of a variety of pathogens. This paper will provide a broad overview of the novel achievements in the field of pathogen sensing by focusing on methods and devices that compliment microfluidics.

  12. Microfluidic systems for pathogen sensing: a review.

    Science.gov (United States)

    Mairhofer, Jürgen; Roppert, Kriemhilt; Ertl, Peter

    2009-01-01

    Rapid pathogen sensing remains a pressing issue today since conventional identification methodsare tedious, cost intensive and time consuming, typically requiring from 48 to 72 h. In turn, chip based technologies, such as microarrays and microfluidic biochips, offer real alternatives capable of filling this technological gap. In particular microfluidic biochips make the development of fast, sensitive and portable diagnostic tools possible, thus promising rapid and accurate detection of a variety of pathogens. This paper will provide a broad overview of the novel achievements in the field of pathogen sensing by focusing on methods and devices that compliment microfluidics.

  13. Detection of low-abundance KRAS mutations in colorectal cancer using microfluidic capillary electrophoresis-based restriction fragment length polymorphism method with optimized assay conditions.

    Directory of Open Access Journals (Sweden)

    Huidan Zhang

    Full Text Available Constitutively active KRAS mutations have been found to be involved in various processes of cancer development, and render tumor cells resistant to EGFR-targeted therapies. Mutation detection methods with higher sensitivity will increase the possibility of choosing the correct individual therapy. Here, we established a highly sensitive and efficient microfluidic capillary electrophoresis-based restriction fragment length polymorphism (µCE-based RFLP platform for low-abundance KRAS genotyping with the combination of µCE and RFLP techniques. By using our self-built sensitive laser induced fluorescence (LIF detector and a new DNA intercalating dye YOYO-1, the separation conditions of µCE for ΦX174 HaeIII DNA marker were first optimized. Then, a Mav I digested 107-bp KRAS gene fragment was directly introduced into the microfluidic device and analyzed by µCE, in which field amplified sample stacking (FASS technique was employed to obtain the enrichment of the RFLP digestion products and extremely improved the sensitivity. The accurate analysis of KRAS statuses in HT29, LS174T, CCL187, SW480, Clone A, and CX-1 colorectal cancer (CRC cell lines by µCE-based RFLP were achieved in 5 min with picoliter-scale sample consumption, and as low as 0.01% of mutant KRAS could be identified from a large excess of wild-type genomic DNA (gDNA. In 98 paraffin-embedded CRC tissues, KRAS codon 12 mutations were discovered in 28 (28.6%, significantly higher than that obtained by direct sequencing (13, 13.3%. Clone sequencing confirmed these results and showed this system could detect at least 0.4% of the mutant KRAS in CRC tissue slides. Compared with direct sequencing, the new finding of the µCE-based RFLP platform was that KRAS mutations in codon 12 were correlated with the patient's age. In conclusion, we established a sensitive, fast, and cost-effective screening method for KRAS mutations, and successfully detected low-abundance KRAS mutations in clinical

  14. Capturing CD4 cells using a functionalized circular microfluidic device and glutaraldehyde as biolinker for tuberculosis detection and diagnosis

    Science.gov (United States)

    Shih, Yeu-Farn; Huang, Nien-Tsu; Lee, Chih-Kung

    2015-03-01

    It is estimated that about one-third of the world's population has already been infected by tuberculosis. Mycobacterium tuberculosis, in general, can result in an active case of tuberculosis in approximately 5%-10% of those who suffer from latent tuberculosis and the chance of becoming ill is the highest within one of year of getting the disease. Although a newly developed methods called interferon gamma release assay (IGRA) can monitor CD4 cells secreted cytokine to diagnose tuberculosis (TB) condition. However, it is difficult to count total numbers of cytokine secreted CD4 cells, which make the diagnosis less accurate. Therefore, we develop a functionalized polydimethylsiloxane (PDMS) device using glutaraldehyde to capture CD4 cells. To enhance the capture efficiency, we use COMSOL simulation to optimize the arrangement of PDMS micro pillars to make cells uniformly distributed in the device. Our preliminary data showed the microfluidic configuration in a circular shape with HCP patterned micro pillars turned 30 degrees offers the highest cell capture rate.

  15. Microfluidic Dye Lasers

    DEFF Research Database (Denmark)

    Kristensen, Anders; Balslev, Søren; Gersborg-Hansen, Morten

    2006-01-01

    A technology for miniaturized, polymer based lasers, suitable for integration with planar waveguides and microfluidic networks is presented. The microfluidic dye laser device consists of a microfluidic channel with an embedded optical resonator. The devices are fabricated in a thin polymer film...

  16. Microfluidic sieve valves

    Science.gov (United States)

    Quake, Stephen R; Marcus, Joshua S; Hansen, Carl L

    2015-01-13

    Sieve valves for use in microfluidic device are provided. The valves are useful for impeding the flow of particles, such as chromatography beads or cells, in a microfluidic channel while allowing liquid solution to pass through the valve. The valves find particular use in making microfluidic chromatography modules.

  17. Microfluidic single sperm analysis

    NARCIS (Netherlands)

    Wagenaar, de Bjorn

    2016-01-01

    Microfluidic technology has been occasionally used for in vitro analysis and separation of cells. The small dimensions of microfluidic chips are very suitable to study cells on the single cell level rather than in whole populations. Also sperm cells have been studied and manipulated using microfluid

  18. Femtosecond laser fabrication for the integration of optical sensors in microfluidic lab-on-chip devices

    NARCIS (Netherlands)

    Osellame, R.; Martinez-Vazquez, R.; Dongre, C.; Dekker, R.; Hoekstra, H.J.W.M.; Ramponi, R.; Pollnau, M.; Cerullo, G.; Corkum, P.; Silvestri, de S.; Nelson, K.A.; Riedle, E.; Schoenlein, R.W.

    2009-01-01

    Femtosecond lasers enable the fabrication of both optical waveguides and buried microfluidic channels on a glass substrate. The waveguides are used to integrate optical detection in a commercial microfluidic lab-on-chip for capillary electrophoresis.

  19. Femtosecond laser fabrication for the integration of optical sensors in microfluidic lab-on-chip devices

    NARCIS (Netherlands)

    Osellame, R.; Martinez Vazquez, R.; Dongre, C.; Dekker, R.; Hoekstra, H.J.W.M.; Pollnau, M.; Ramponi, R.; Cerullo, G.

    2008-01-01

    Femtosecond lasers enable the fabrication of both optical waveguides and buried microfluidic channels on a glass substrate. The waveguides are used to integrate optical detection in a commercial microfluidic lab-on-chip for capillary electrophoresis

  20. On-line gaseous formaldehyde detection by a microfluidic analytical method based on simultaneous uptake and derivatization in a temperature controlled annular flow.

    Science.gov (United States)

    Guglielmino, Maud; Bernhardt, Pierre; Trocquet, Claire; Serra, Christophe A; Le Calvé, Stéphane

    2017-09-01

    This paper is focused on the improvement of a microfluidic analytical method for the detection of low airborne formaldehyde concentrations, based on only two distinct steps permitting to reduce the response time and to improve the compactness of the device. First, gaseous formaldehyde is trapped into an acetylacetone solution at 65°C through an annular liquid/gas flow and reacts immediately to form 3,5-Diacetyl-1,4-dihydrolutidine which is then quantified by colorimetry using a liquid core waveguide (LCW). To obtain an annular flow, 3 different hydrophilic silica capillaries of 320, 450 and 530µm ID were tested and the corresponding phase diagrams were obtained in the ranges of liquid and gas flows of 5-35µLmin(-1) and 5-35mLmin(-1) respectively. Finally, the analytical performances were determined using the lowest flow values of 5µLmin(-1) and 5NmLmin(-1), ensuring an annular flow and increasing the microdevice autonomy. If the uptake yield of gaseous formaldehyde into the solution was close to 100%, only the 530µm ID capillary permits to obtain a reaction time long enough for a full conversion of formaldehyde into 3,5-Diacetyl-1,4-dihydrolutidine. With a LCW pathlength of 5cm, the microdevice response was perfectly linear in the range 0-154µgm(-3) with a detection limit of 1.8µgm(-3). Copyright © 2017 Elsevier B.V. All rights reserved.

  1. Detection and traceability of genetically modified organisms in the food production chain

    NARCIS (Netherlands)

    Miraglia, M.; Berdal, K.G.; Brera, C.; Corbisier, P.; Holst - Jensen, A.; Kok, E.J.; Marvin, H.J.P.; Schimmel, H.; Rentsch, J.; Rie, van J.P.P.F.; Zagon, J.

    2004-01-01

    Both labelling and traceability of genetically modified organisms are current issues that are considered in trade and regulation. Currently, labelling of genetically modified foods containing detectable transgenic material is required by EU legislation. A proposed package of legislation would extend

  2. Detection and traceability of genetically modified organisms in the food production chain

    NARCIS (Netherlands)

    Miraglia, M.; Berdal, K.G.; Brera, C.; Corbisier, P.; Holst - Jensen, A.; Kok, E.J.; Marvin, H.J.P.; Schimmel, H.; Rentsch, J.; Rie, van J.P.P.F.; Zagon, J.

    2004-01-01

    Both labelling and traceability of genetically modified organisms are current issues that are considered in trade and regulation. Currently, labelling of genetically modified foods containing detectable transgenic material is required by EU legislation. A proposed package of legislation would extend

  3. Structure and fabrication details of an integrated modularized microfluidic system

    Directory of Open Access Journals (Sweden)

    Qingchang Tian

    2015-12-01

    Full Text Available This article contains schemes, original experimental data and figures for an integrated modularized microfluidic system described in “An integrated microfluidic system for bovine DNA purification and digital PCR detection [1]”. In this data article, we described the structure and fabrication of the integrated modularized microfluidic system. This microfluidic system was applied to isolate DNA from ovine tissue lysate and detect the bovine DNA with digital PCR (dPCR. The DNA extraction efficiency of the microdevice was compared with the efficiency of benchtop protocol.

  4. Manufacturing methods and applications of membranes in microfluidics.

    Science.gov (United States)

    Chen, Xueye; Shen, Jienan; Hu, Zengliang; Huo, Xuyao

    2016-12-01

    Applications of membranes in microfluidics solved many thorny problems for analytical chemistry and bioscience, so that the use of membranes in microfluidics has been a topic of growing interest. Many different examples have been reported, demonstrating the versatile use of membranes. This work reviews a lot of applications of membranes in microfluidics. Membranes in microfluidics for applications including chemical reagents detection, gas detection, drug screening, cell, protein, microreactor, electrokinetical fluid, pump and valve and fluid transport control and so on, have been analyzed and discussed. In addition, the definition and basic concepts of membranes are summed up. And the methods of manufacturing membranes in microfluidics are discussed. This paper will provide a helpful reference to researchers who want to study applications of membranes in microfluidics.

  5. Integrated microchip incorporating atomic magnetometer and microfluidic channel for NMR and MRI

    Science.gov (United States)

    Ledbetter, Micah P.; Savukov, Igor M.; Budker, Dmitry; Shah, Vishal K.; Knappe, Svenja; Kitching, John; Michalak, David J.; Xu, Shoujun; Pines, Alexander

    2011-08-09

    An integral microfluidic device includes an alkali vapor cell and microfluidic channel, which can be used to detect magnetism for nuclear magnetic resonance (NMR) and magnetic resonance imaging (MRI). Small magnetic fields in the vicinity of the vapor cell can be measured by optically polarizing and probing the spin precession in the small magnetic field. This can then be used to detect the magnetic field of in encoded analyte in the adjacent microfluidic channel. The magnetism in the microfluidic channel can be modulated by applying an appropriate series of radio or audio frequency pulses upstream from the microfluidic chip (the remote detection modality) to yield a sensitive means of detecting NMR and MRI.

  6. Cardio Vascular Detection with Neuro Computing and Genetic Algorithm

    Directory of Open Access Journals (Sweden)

    T. John Peter

    2014-09-01

    Full Text Available For human the most fundamental requirement is having a healthy life, which is being difficult to maintain day to day as we are getting more progress in technological era. Among the possible reasons of unnatural death, heart disease based causes are showing very significant part. The diagnosis of heart diseases is a vital and intricate job. The recognition of heart disease from diverse features or signs is a multi-layered problem that is highly sensitive with respect diagnostic tests and establishing the relationship with multiple parameters is very difficult. In result decision is not free from false assumptions and is frequently accompanied by impulsive effects. This encourages developing a more reliable and cost effective knowledge based algorithmic approach to detect the heart disease. From engineering point of view, solution for detecting the presence of heart diseases is developed with the concept of artificial intelligence in data mining in this study. Feed forward architecture of neural network technology is taken as platform of computation to generate the intelligence in association with well established field of genetic algorithm (GA. A comparative performance has presented between both learning concepts with various different size of architecture.

  7. Bearing Fault Detection Using Artificial Neural Networks and Genetic Algorithm

    Directory of Open Access Journals (Sweden)

    Samanta B

    2004-01-01

    Full Text Available A study is presented to compare the performance of bearing fault detection using three types of artificial neural networks (ANNs, namely, multilayer perceptron (MLP, radial basis function (RBF network, and probabilistic neural network (PNN. The time domain vibration signals of a rotating machine with normal and defective bearings are processed for feature extraction. The extracted features from original and preprocessed signals are used as inputs to all three ANN classifiers: MLP, RBF, and PNN for two-class (normal or fault recognition. The characteristic parameters like number of nodes in the hidden layer of MLP and the width of RBF, in case of RBF and PNN along with the selection of input features, are optimized using genetic algorithms (GA. For each trial, the ANNs are trained with a subset of the experimental data for known machine conditions. The ANNs are tested using the remaining set of data. The procedure is illustrated using the experimental vibration data of a rotating machine with and without bearing faults. The results show the relative effectiveness of three classifiers in detection of the bearing condition.

  8. Spintronic microfluidic platform for biomedical and environmental applications

    Science.gov (United States)

    Cardoso, F. A.; Martins, V. C.; Fonseca, L. P.; Germano, J.; Sousa, L. A.; Piedade, M. S.; Freitas, P. P.

    2010-09-01

    Faster, more sensitive and easy to operate biosensing devices still are a need at important areas such as biomedical diagnostics, food control and environmental monitoring. Recently, spintronic-devices have emerged as a promising alternative to the existent technologies [1-3]. A number of advantages, namely high sensitivity, easy integration, miniaturization, scalability, robustness and low cost make these devices potentially capable of responding to the existent technological need. In parallel, the field of microfluidics has shown great advances [4]. Microfluidic systems allow the analysis of small sample volumes (from micro- down to pico-liters), often by automate sample processing with the ability to integrate several steps into a single device (analyte amplification, concentration, separation and/or labeling), all in a reduced assay time (minutes to hours) and affordable cost. The merging of these two technologies, magnetoresistive biochips and microfluidics, will enable the development of highly competitive devices. This work reports the integration of a magnetoresistive biochip with a microfluidic system inside a portable and autonomous electronic platform aiming for a fully integrated device. A microfluidic structure fabricated in polydimethylsiloxane with dimensions of W: 0.5mm, H: 0.1mm, L: 10mm, associated to a mechanical system to align and seal the channel by pressure is presented (Fig. 1) [5]. The goal is to perform sample loading and transportation over the chip and simultaneously control the stringency and uniformity of the wash-out process. The biochip output is acquired by an electronic microsystem incorporating the circuitry to control, address and read-out the 30 spin-valve sensors sequentially (Fig. 1) [2]. This platform is being applied to the detection of water-borne microbial pathogens (e.g. Salmonella and Escherichia coli) and genetic diseases diagnosis (e.g. cystic fibrosis) through DNA hybridization assays. Open chamber measurements were

  9. Lab-on-chip system combining a microfluidic-ELISA with an array of amorphous silicon photosensors for the detection of celiac disease epitopes

    National Research Council Canada - National Science Library

    Francesca Costantini; Cristiana Sberna; Giulia Petrucci; Cesare Manetti; Giampiero de Cesare; Augusto Nascetti; Domenico Caputo

    2015-01-01

    This work presents a lab-on-chip system, which combines a glass-polydimethilsiloxane microfluidic network and an array of amorphous silicon photosensors for the diagnosis and follow-up of Celiac disease...

  10. Integrated microfluidic systems for DNA analysis.

    Science.gov (United States)

    Njoroge, Samuel K; Chen, Hui-Wen; Witek, Małgorzata A; Soper, Steven A

    2011-01-01

    The potential utility of genome-related research in terms of evolving basic discoveries in biology has generated widespread use of DNA diagnostics and DNA forensics and driven the accelerated development of fully integrated microfluidic systems for genome processing. To produce a microsystem with favorable performance characteristics for genetic-based analyses, several key operational elements must be strategically chosen, including device substrate material, temperature control, fluidic control, and reaction product readout. As a matter of definition, a microdevice is a chip that performs a single processing step, for example microchip electrophoresis. Several microdevices can be integrated to a single wafer, or combined on a control board as separate devices to form a microsystem. A microsystem is defined as a chip composed of at least two microdevices. Among the many documented analytical microdevices, those focused on the ability to perform the polymerase chain reaction (PCR) have been reported extensively due to the importance of this processing step in most genetic-based assays. Other microdevices that have been detailed in the literature include those for solid-phase extractions, microchip electrophoresis, and devices composed of DNA microarrays used for interrogating DNA primary structure. Great progress has also been made in the areas of chip fabrication, bonding and sealing to enclose fluidic networks, evaluation of different chip substrate materials, surface chemistries, and the architecture of reaction conduits for basic processing steps such as mixing. Other important elements that have been developed to realize functional systems include miniaturized readout formats comprising optical or electrochemical transduction and interconnect technologies. These discoveries have led to the development of fully autonomous and functional integrated systems for genome processing that can supply "sample in/answer out" capabilities. In this chapter, we focus on

  11. Microchip CE analysis of amino acids on a titanium dioxide nanoparticles-coated PDMS microfluidic device with in-channel indirect amperometric detection.

    Science.gov (United States)

    Qiu, Jian-Ding; Wang, Li; Liang, Ru-Ping; Wang, Jing-Wu

    2009-10-01

    In this paper, titanium dioxide nanoparticles (TiO(2) NPs) were employed to construct a functional film on PDMS microfluidic channel surface, which was formed by sequentially immobilizing poly(diallyldimethylammonium chloride) and TiO(2) NPs on PDMS surface by layer-by-layer assembly technique. The modified PDMS microchip exhibited a decreased and stable EOF, which was favorable for the separation of biomolecules with similar migration times. Arginine, phenylalanine, serine and threonine were used as model analytes to evaluate the performance of the modified microchip. The four amino acids were efficiently separated within 100 s in a 3.7 cm long separation channel and successfully detected on the carbon fiber electrode in conjunction with in-channel indirect amperometry. Resolutions and theoretical plate numbers of the analytes were considerably enhanced in the presence of TiO(2) NPs. The modified microchip demonstrated excellent stability and reproducibility with improved RSDs of migration times and peak currents for run-to-run, day-to-day and chip-to-chip analyses, respectively. Variables influencing the separation efficiency and amperometric response, including injection and separation voltage, the working electrode position and buffer concentration, were optimized in detail.

  12. A multiplexable, microfluidic platform for the rapid quantitation of a biomarker panel for early ovarian cancer detection at the point-of-care.

    Science.gov (United States)

    Shadfan, Basil H; Simmons, Archana R; Simmons, Glennon W; Ho, Andy; Wong, Jorge; Lu, Karen H; Bast, Robert C; McDevitt, John T

    2015-01-01

    Point-of-care (POC) diagnostic platforms have the potential to enable low-cost, large-scale screening. As no single biomarker is shed by all ovarian cancers, multiplexed biomarker panels promise improved sensitivity and specificity to address the unmet need for early detection of ovarian cancer. We have configured the programmable bio-nano-chip (p-BNC)-a multiplexable, microfluidic, modular platform-to quantify a novel multi-marker panel comprising CA125, HE4, MMP-7, and CA72-4. The p-BNC is a bead-based immunoanalyzer system with a credit-card-sized footprint that integrates automated sample metering, bubble and debris removal, reagent storage and waste disposal, permitting POC analysis. Multiplexed p-BNC immunoassays demonstrated high specificity, low cross-reactivity, low limits of detection suitable for early detection, and a short analysis time of 43 minutes. Day-to-day variability, a critical factor for longitudinally monitoring biomarkers, ranged between 5.4% and 10.5%, well below the biologic variation for all four markers. Biomarker concentrations for 31 late-stage sera correlated well (R(2) = 0.71 to 0.93 for various biomarkers) with values obtained on the Luminex platform. In a 31 patient cohort encompassing early- and late-stage ovarian cancers along with benign and healthy controls, the multiplexed p-BNC panel was able to distinguish cases from controls with 68.7% sensitivity at 80% specificity. Utility for longitudinal biomarker monitoring was demonstrated with prediagnostic plasma from 2 cases and 4 controls. Taken together, the p-BNC shows strong promise as a diagnostic tool for large-scale screening that takes advantage of faster results and lower costs while leveraging possible improvement in sensitivity and specificity from biomarker panels.

  13. Versatile microfluidic total internal reflection (TIR)-based devices: application to microbeads velocity measurement and single molecule detection with upright and inverted microscope.

    Science.gov (United States)

    Le, Nam Cao Hoai; Yokokawa, Ryuji; Dao, Dzung Viet; Nguyen, Thien Duy; Wells, John C; Sugiyama, Susumu

    2009-01-21

    A poly(dimethylsiloxane) (PDMS) chip for Total Internal Reflection (TIR)-based imaging and detection has been developed using Si bulk micromachining and PDMS casting. In this paper, we report the applications of the chip on both inverted and upright fluorescent microscopes and confirm that two types of sample delivery platforms, PDMS microchannel and glass microchannel, can be easily integrated depending on the magnification of an objective lens needed to visualize a sample. Although any device configuration can be achievable, here we performed two experiments to demonstrate the versatility of the microfluidic TIR-based devices. The first experiment was velocity measurement of Nile red microbeads with nominal diameter of 500 nm in a pressure-driven flow. The time-sequenced fluorescent images of microbeads, illuminated by an evanescent field, were cross-correlated by a Particle Image Velocimetry (PIV) program to obtain near-wall velocity field of the microbeads at various flow rates from 500 nl/min to 3000 nl/min. We then evaluated the capabilities of the device for Single Molecule Detection (SMD) of fluorescently labeled DNA molecules from 30 bp to 48.5 kbp and confirm that DNA molecules as short as 1105 bp were detectable. Our versatile, integrated device could provide low-cost and fast accessibility to Total Internal Reflection Fluorescent Microscopy (TIRFM) on both conventional upright and inverted microscopes. It could also be a useful component in a Micro-Total Analysis System (micro-TAS) to analyze nanoparticles or biomolecules near-wall transport or motion.

  14. Reliability of genetic bottleneck tests for detecting recent population declines

    NARCIS (Netherlands)

    Peery, M. Zachariah; Kirby, Rebecca; Reid, Brendan N.; Stoelting, Ricka; Doucet-Beer, Elena; Robinson, Stacie; Vasquez-Carrillo, Catalina; Pauli, Jonathan N.; Palsboll, Per J.

    2012-01-01

    The identification of population bottlenecks is critical in conservation because populations that have experienced significant reductions in abundance are subject to a variety of genetic and demographic processes that can hasten extinction. Genetic bottleneck tests constitute an appealing and popula

  15. Overview of the microfluidic diagnostics commercial landscape.

    Science.gov (United States)

    Kim, Lily

    2013-01-01

    Since its birth in the late 1980s, the field of microfluidics has continued to mature, with a growing number of companies pursuing diagnostic applications. In 2009 the worldwide in vitro diagnostics market was estimated at >$40 billion USD, and microfluidic diagnostics are poised to reap a significant part of this market across a range of areas including laboratory diagnostics, point-of-care diagnostics, cancer diagnostics, and others. The potential economic advantages of microfluidics are numerous and compelling: lower reagent and/or sample volumes, lower equipment costs, improved portability, increased automation, and increased measurement speed. All of these factors may help put more information in the hands of doctors and patients sooner, enabling earlier disease detection and more tailored, effective treatments. This chapter reviews the microfluidic diagnostics commercial landscape and discusses potential commercialization challenges and opportunities.

  16. Preliminary application of microfluidic chip on quantitative detection of oral bacteria%微流芯片在口腔细菌定量检测中的初步应用

    Institute of Scientific and Technical Information of China (English)

    余洋

    2012-01-01

    微流芯片定量测菌法是利用微加工技术在芯片上进行细菌定量检测的一种先进方法,关于口腔细菌学研究涉及的方法技术十分广泛,随着科技快速发展,微流芯片技术也引入到口腔细菌定量检测中,本文就该领域研究现状做一综述.%Microfluidic chip technology is an advanced method to quantitatively measure bacteria using mi-cro-processing technology on a chip. Oral bacteriological research involves a wide range of methods and techniques. With the rapid development of science and technology, microfluidic chip technology has also been used for the quantitative detection of oral bacteria. In this review article, the application of microfluidic chip on quantitative detection of oral bacteria will be summarized.

  17. Microfabrication and Applications of Opto-Microfluidic Sensors

    Directory of Open Access Journals (Sweden)

    Daiying Zhang

    2011-05-01

    Full Text Available A review of research activities on opto-microfluidic sensors carried out by the research groups in Canada is presented. After a brief introduction of this exciting research field, detailed discussion is focused on different techniques for the fabrication of opto-microfluidic sensors, and various applications of these devices for bioanalysis, chemical detection, and optical measurement. Our current research on femtosecond laser microfabrication of optofluidic devices is introduced and some experimental results are elaborated. The research on opto-microfluidics provides highly sensitive opto-microfluidic sensors for practical applications with significant advantages of portability, efficiency, sensitivity, versatility, and low cost.

  18. Unintended effects and their detection in genetically modified crops.

    Science.gov (United States)

    Cellini, F; Chesson, A; Colquhoun, I; Constable, A; Davies, H V; Engel, K H; Gatehouse, A M R; Kärenlampi, S; Kok, E J; Leguay, J-J; Lehesranta, S; Noteborn, H P J M; Pedersen, J; Smith, M

    2004-07-01

    The commercialisation of GM crops in Europe is practically non-existent at the present time. The European Commission has instigated changes to the regulatory process to address the concerns of consumers and member states and to pave the way for removing the current moratorium. With regard to the safety of GM crops and products, the current risk assessment process pays particular attention to potential adverse effects on human and animal health and the environment. This document deals with the concept of unintended effects in GM crops and products, i.e. effects that go beyond that of the original modification and that might impact primarily on health. The document first deals with the potential for unintended effects caused by the processes of transgene insertion (DNA rearrangements) and makes comparisons with genetic recombination events and DNA rearrangements in traditional breeding. The document then focuses on the potential value of evolving "profiling" or "omics" technologies as non-targeted, unbiased approaches, to detect unintended effects. These technologies include metabolomics (parallel analysis of a range of primary and secondary metabolites), proteomics (analysis of polypeptide complement) and transcriptomics (parallel analysis of gene expression). The technologies are described, together with their current limitations. Importantly, the significance of unintended effects on consumer health are discussed and conclusions and recommendations presented on the various approaches outlined.

  19. Genetically modified cotton in India and detection strategies.

    Science.gov (United States)

    Randhawa, Gurinder Jit; Chhabra, Rashmi

    2013-01-01

    India is one of the largest cotton-growing countries. Cotton is a fiber crop with varied applications from making tiny threads to fashionable clothing in the textile sector. In the near future, cotton crop will gain popularity as a multipurpose crop in India. The commercialization of Bt cotton in 2002 and consequently the fast adoption of Bt cotton hybrids by cotton farmers have enhanced the cotton production in India. Presently, genetically modified (GM) cotton has occupied 21.0 million hectares (mha) that comprise 14% of the global area under GM cultivation. In the coming years, improved cotton hybrids, with stacked and multiple gene events for improved fiber quality, insect resistance, drought tolerance, and herbicide tolerance, would further significantly improve the cotton production in India. With the dramatic increase in commercialization of GM crops, there is an urgent need to develop cost-effective and robust GM detection methods for effective risk assessment and management, post release monitoring, and to solve the legal disputes. DNA-based GM diagnostics are most robust assays due to their high sensitivity, specificity, and stability of DNA molecule.

  20. Spiral microfluidic nanoparticle separators

    Science.gov (United States)

    Bhagat, Ali Asgar S.; Kuntaegowdanahalli, Sathyakumar S.; Dionysiou, Dionysios D.; Papautsky, Ian

    2008-02-01

    Nanoparticles have potential applications in many areas such as consumer products, health care, electronics, energy and other industries. As the use of nanoparticles in manufacturing increases, we anticipate a growing need to detect and measure particles of nanometer scale dimensions in fluids to control emissions of possible toxic nanoparticles. At present most particle separation techniques are based on membrane assisted filtering schemes. Unfortunately their efficiency is limited by the membrane pore size, making them inefficient for separating a wide range of sizes. In this paper, we propose a passive spiral microfluidic geometry for momentum-based particle separations. The proposed design is versatile and is capable of separating particulate mixtures over a wide dynamic range and we expect it will enable a variety of environmental, medical, or manufacturing applications that involve rapid separation of nanoparticles in real-world samples with a wide range of particle components.

  1. Semiconductor sensor embedded microfluidic chip for protein biomarker detection using a bead-based immunoassay combined with deoxyribonucleic acid strand labeling.

    Science.gov (United States)

    Lin, Yen-Heng; Peng, Po-Yu

    2015-04-15

    Two major issues need to be addressed in applying semiconductor biosensors to detecting proteins in immunoassays. First, the length of the antibody on the sensor surface surpasses the Debye lengths (approximately 1 nm, in normal ionic strength solution), preventing certain specifically bound proteins from being tightly attached to the sensor surface. Therefore, these proteins do not contribute to the sensor's surface potential change. Second, these proteins carry a small charge and can be easily affected by the pH of the surrounding solution. This study proposes a magnetic bead-based immunoassay using a secondary antibody to label negatively charged DNA fragments for signal amplification. An externally imposed magnetic force attaches the analyte tightly to the sensor surface, thereby effectively solving the problem of the analyte protein's distance to the sensor surface surpassing the Debye lengths. In addition, a normal ion intensity buffer can be used without dilution for the proposed method. Experiments revealed that the sensitivity can be improved by using a longer DNA fragment for labeling and smaller magnetic beads as solid support for the antibody. By using a 90 base pair DNA label, the signal was 15 times greater than that without labeling. In addition, by using a 120 nm magnetic bead, a minimum detection limit of 12.5 ng mL(-1) apolipoprotein A1 can be measured. Furthermore, this study integrates a semiconductor sensor with a microfluidic chip. With the help of microvalves and micromixers in the chip, the length of the mixing step for each immunoassay has been reduced from 1h to 20 min, and the sample volume has been reduced from 80 μL to 10 μL. In practice, a protein biomarker in a urinary bladder cancer patient's urine was successfully measured using this technique. This study provides a convenient and effective method to measure protein using a semiconductor sensor.

  2. Integrated Microfluidic Sensor System with Magnetostrictive Resonators

    KAUST Repository

    Liang, Cai

    2011-12-08

    The present embodiments describe a method that integrates a magnetostrictive sensor with driving and detecting elements into a microfluidic chip to detect a chemical, biochemical or biomedical species. These embodiments may also measure the properties of a fluid such as viscosity, pH values. The whole system can be referred to lab-on-a-chip (LOC) or micro-total-analysis-systems (.mu.TAS). In particular, this present embodiments include three units, including a microfluidics unit, a magnetostrictive sensor, and driving/detecting elements. An analyzer may also be provided to analyze an electrical signal associated with a feature of a target specimen.

  3. Digital Microfluidics Sample Analyzer

    Science.gov (United States)

    Pollack, Michael G.; Srinivasan, Vijay; Eckhardt, Allen; Paik, Philip Y.; Sudarsan, Arjun; Shenderov, Alex; Hua, Zhishan; Pamula, Vamsee K.

    2010-01-01

    Three innovations address the needs of the medical world with regard to microfluidic manipulation and testing of physiological samples in ways that can benefit point-of-care needs for patients such as premature infants, for which drawing of blood for continuous tests can be life-threatening in their own right, and for expedited results. A chip with sample injection elements, reservoirs (and waste), droplet formation structures, fluidic pathways, mixing areas, and optical detection sites, was fabricated to test the various components of the microfluidic platform, both individually and in integrated fashion. The droplet control system permits a user to control droplet microactuator system functions, such as droplet operations and detector operations. Also, the programming system allows a user to develop software routines for controlling droplet microactuator system functions, such as droplet operations and detector operations. A chip is incorporated into the system with a controller, a detector, input and output devices, and software. A novel filler fluid formulation is used for the transport of droplets with high protein concentrations. Novel assemblies for detection of photons from an on-chip droplet are present, as well as novel systems for conducting various assays, such as immunoassays and PCR (polymerase chain reaction). The lab-on-a-chip (a.k.a., lab-on-a-printed-circuit board) processes physiological samples and comprises a system for automated, multi-analyte measurements using sub-microliter samples of human serum. The invention also relates to a diagnostic chip and system including the chip that performs many of the routine operations of a central labbased chemistry analyzer, integrating, for example, colorimetric assays (e.g., for proteins), chemiluminescence/fluorescence assays (e.g., for enzymes, electrolytes, and gases), and/or conductometric assays (e.g., for hematocrit on plasma and whole blood) on a single chip platform.

  4. Integrated Microfluidic Reactors.

    Science.gov (United States)

    Lin, Wei-Yu; Wang, Yanju; Wang, Shutao; Tseng, Hsian-Rong

    2009-12-01

    Microfluidic reactors exhibit intrinsic advantages of reduced chemical consumption, safety, high surface-area-to-volume ratios, and improved control over mass and heat transfer superior to the macroscopic reaction setting. In contract to a continuous-flow microfluidic system composed of only a microchannel network, an integrated microfluidic system represents a scalable integration of a microchannel network with functional microfluidic modules, thus enabling the execution and automation of complicated chemical reactions in a single device. In this review, we summarize recent progresses on the development of integrated microfluidics-based chemical reactors for (i) parallel screening of in situ click chemistry libraries, (ii) multistep synthesis of radiolabeled imaging probes for positron emission tomography (PET), (iii) sequential preparation of individually addressable conducting polymer nanowire (CPNW), and (iv) solid-phase synthesis of DNA oligonucleotides. These proof-of-principle demonstrations validate the feasibility and set a solid foundation for exploring a broad application of the integrated microfluidic system.

  5. Commercialization of microfluidic devices.

    Science.gov (United States)

    Volpatti, Lisa R; Yetisen, Ali K

    2014-07-01

    Microfluidic devices offer automation and high-throughput screening, and operate at low volumes of consumables. Although microfluidics has the potential to reduce turnaround times and costs for analytical devices, particularly in medical, veterinary, and environmental sciences, this enabling technology has had limited diffusion into consumer products. This article analyzes the microfluidics market, identifies issues, and highlights successful commercialization strategies. Addressing niche markets and establishing compatibility with existing workflows will accelerate market penetration. Copyright © 2014 Elsevier Ltd. All rights reserved.

  6. Tunable Microfluidic Dye Laser

    DEFF Research Database (Denmark)

    Olsen, Brian Bilenberg; Helbo, Bjarne; Kutter, Jörg Peter

    2003-01-01

    We present a tunable microfluidic dye laser fabricated in SU-8. The tunability is enabled by integrating a microfluidic diffusion mixer with an existing microfluidic dye laser design by Helbo et al. By controlling the relative flows in the mixer between a dye solution and a solvent......, the concentration of dye in the laser cavity can be adjusted, allowing the wavelength to be tuned. Wavelength tuning controlled by the dye concentration was demonstrated with macroscopic dye lasers already in 1971, but this principle only becomes practically applicable by the use of microfluidic mixing...

  7. A novel label-free microfluidic paper-based immunosensor for highly sensitive electrochemical detection of carcinoembryonic antigen.

    Science.gov (United States)

    Wang, Yang; Xu, Huiren; Luo, Jinping; Liu, Juntao; Wang, Li; Fan, Yan; Yan, Shi; Yang, Yue; Cai, Xinxia

    2016-09-15

    In this work, a highly sensitive label-free paper-based electrochemical immunosensor employing screen-printed working electrode (SPWE) for detection of carcinoembryonic antigen (CEA) was fabricated. In order to raise the detection sensitivity and immobilize anti-CEA, amino functional graphene (NH2-G)/thionine (Thi)/gold nanoparticles (AuNPs) nanocomposites were synthesized and coated on SPWE. The principle of the immunosensor determination was based on the fact that the decreased response currents of Thi were proportional to the concentrations of corresponding antigens due to the formation of antibody-antigen immunocomplex. Experimental results revealed that the immunoassay enabled the determination of standard CEA solutions with linear working ranges of 50pgmL(-1) to 500ngmL(-1), the limit of detections for CEA is 10pgmL(-1) (S/N=3) and its corresponding correlation coefficients were 0.996. Furthermore, the proposed immunosensor could be used for the determination of clinical serum samples. A large number of clinical serum samples were detected and the relative errors between measured values and reference concentrations were calculated. Results showed that this novel paper-based electrochemical immunosensor could provide a new platform for low cost, sensitive, specific, and point-of-care diagnosis in cancer detection.

  8. Microfluidic Devices in Advanced Caenorhabditis elegans Research

    Directory of Open Access Journals (Sweden)

    Muniesh Muthaiyan Shanmugam

    2016-08-01

    Full Text Available The study of model organisms is very important in view of their potential for application to human therapeutic uses. One such model organism is the nematode worm, Caenorhabditis elegans. As a nematode, C. elegans have ~65% similarity with human disease genes and, therefore, studies on C. elegans can be translated to human, as well as, C. elegans can be used in the study of different types of parasitic worms that infect other living organisms. In the past decade, many efforts have been undertaken to establish interdisciplinary research collaborations between biologists, physicists and engineers in order to develop microfluidic devices to study the biology of C. elegans. Microfluidic devices with the power to manipulate and detect bio-samples, regents or biomolecules in micro-scale environments can well fulfill the requirement to handle worms under proper laboratory conditions, thereby significantly increasing research productivity and knowledge. The recent development of different kinds of microfluidic devices with ultra-high throughput platforms has enabled researchers to carry out worm population studies. Microfluidic devices primarily comprises of chambers, channels and valves, wherein worms can be cultured, immobilized, imaged, etc. Microfluidic devices have been adapted to study various worm behaviors, including that deepen our understanding of neuromuscular connectivity and functions. This review will provide a clear account of the vital involvement of microfluidic devices in worm biology.

  9. Dynamics of Microvalve Operations in Integrated Microfluidics

    Directory of Open Access Journals (Sweden)

    Alan T. H. Lau

    2014-02-01

    Full Text Available Pneumatic microvalves are widely used key components for automating liquid manipulation and flow control in microfluidics for more than one decade. Due to their robust operations and the ease of fabrication, tremendous microfluidic systems have been developed with the multiple microvalves for higher throughput and extended functionalities. Therefore, operation performance of the microvalves in the integrated microfluidic devices is crucial to the related applications, in fields such as micro-flows, cell analyses, drug discovery, and physical/chemical detections. It has been reported that operation performance of the microvalves are highly sensitive to the device configuration and pressurization scheme. This implies the further development of integrated microfluidics with a larger number of the valves may suffer the problems of undetermined microvalve behaviors during operations, which can become an unavoidable hurdle in the device design and optimization processes. Herein, we characterize responses of the individual microvalves for different operation configurations, e.g., membrane thicknesses and driving pressures. We investigate also the effects in microfluidics integrated with the more valves, through experiments, modeling and simulations. We show that dynamics of the microvalves is indeed influenced by the configurations, levels of design complexity and positions in the devices. Overall, taken dynamics of the microvalve responses into considerations, this work provides insights and guidelines for better designs of integrated microfluidics for the future applications requiring higher throughput and improved operation performance.

  10. 基于微流控芯片电泳的番茄黄化曲叶病毒快速检测%Microfluidic Electrophoresis Detection of Tomato yellow leaf curl virus(TYLCV)

    Institute of Scientific and Technical Information of China (English)

    余明芬; 曾洪梅; 钟润涛; 赵小明; 邱德文

    2014-01-01

    控芯片电泳进行比较,确立了后者在核酸检测方面的应用价值;通过微流控芯片电泳对TYLCV PCR产物的检测,建立了基于微流控芯片电泳的TYLCV快速检测方法,为TYLCV的快速检测提供新的技术支持。%Objective]The objectives of this study are to explore the effect of microfluidic electrophoresis on detection of PCR products, build a detection method for Tomato yellow leaf curl virus (TYLCV) by electrophoresis in microfluidic chip, and to remedy the defect in reagent consumption, long time, lack of safety of agarose gel electrophoresis.[Method]Primers in relatively stable positions of TYLCV genome were designed, some primers in references were taken into account, and these selected primers were verified. TYLCV primers were screened out based on the criterion of specificity, stability, and sensitivity. DNA standardsφX174/BsuR I (HaeⅢ) marker was subjected to agarose gel electrophoresis and microfluidic electrophoresis, and the two methods were compared in supplies, time-consumption and sensitivity to confirm the value of microfluidic electrophoresis in nucleic acid detection. In order to evaluate the value of microfluidic electrophoresis in virus detection, the PCR amplification products of one pair of selected primers on the actual samples were processed by microfluidic electrophoresis.[Result]Fourteen pairs of TYLCV primers were screened out, 2 pairs came from the literatures and the other 12 pairs were designed in this study. Each pair of primers could meet the requirement for microfluidic detection. TYLCV-T was chosen from these primers for the subsequent study. By comparison of agarose gel electrophoresis and microfluidic electrophoresis, the time consumption and reagent consumption of microfluidic electrophoresis were 1/10 and 1/8 of those of agarose gel electrophoresis, respectively. The detection sensitivity of microfluidic electrophoresis was at least 103 times higher than that of agarose gel

  11. Interfacing microfluidic handling with spectroscopic detection for real-life applications via the lab-on-valve platform: A review

    DEFF Research Database (Denmark)

    Hansen, Elo Harald; Miró, Manuel

    2008-01-01

    with syringe pump propelling devices as a front end to a plethora of spectroscopic detection schemes including UV-Vis spectroscopy, spectrofluorimetry, chemiluminescence, AAS, AFS and ICP-AES/MS. In contrast to lab-on-a-chip units, the versatile configuration of the micromachined LOV readily facilitates...

  12. Functionalization of embedded thiol-ene waveguides for evanescent wave-induced fluorescence detection in a microfluidic device

    DEFF Research Database (Denmark)

    Feidenhans, Nikolaj A.; Jensen, Thomas Glasdam; Lafleur, Josiane P.;

    2013-01-01

    We demonstrate the use of functional surface groups inherently present on off-stoichiometric thiol-ene polymers, for site-specific immobilization of biomolecules and detection by evanescent wave-induced fluorescence. An optofluidic chip featuring an embedded thiol-ene waveguide was selectively fu...

  13. Prevalence and detection of psychosocial problems in cancer genetic counseling

    NARCIS (Netherlands)

    Eijzenga, W.; Bleiker, E.M.A.; Hahn, D.E.E.; van der Kolk, L.E.; Sidharta, G.N.; Aaronson, N.K.

    2015-01-01

    Only a minority of individuals who undergo cancer genetic counseling experience heightened levels of psychological distress, but many more experience a range of cancer genetic-specific psychosocial problems. The aim of this study was to estimate the prevalence of such psychosocial problems, and to i

  14. Microbial detection in microfluidic devices through dual staining of quantum dots-labeled immunoassay and RNA hybridization

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Qing [Division of Environmental Science and Engineering, National University of Singapore, Blk E1A, 07-03, Engineering Drive 2, Singapore 117576 (Singapore); Zhu Liang [Division of Environmental Science and Engineering, National University of Singapore, Blk E1A, 07-03, Engineering Drive 2, Singapore 117576 (Singapore); Feng Hanhua [Institute of Microelectronics (Singapore); Ang, Simon [Department of Electrical Engineering, University of Arkansas, Fayetteville (United States); Chau, F.S. [Department of Mechanical Engineering, National University of Singapore (Singapore); Liu, W.-T. [Division of Environmental Science and Engineering, National University of Singapore, Blk E1A, 07-03, Engineering Drive 2, Singapore 117576 (Singapore)]. E-mail: cveliuwt@nus.edu.sg

    2006-01-18

    This paper reported the development of a microfludic device for the rapid detection of viable and nonviable microbial cells through dual labeling by fluorescent in situ hybridization (FISH) and quantum dots (QDs)-labeled immunofluorescent assay (IFA). The coin sized device consists of a microchannel and filtering pillars (gap = 1-2 {mu}m) and was demonstrated to effectively trap and concentrate microbial cells (i.e. Giardia lamblia). After sample injection, FISH probe solution and QDs-labeled antibody solution were sequentially pumped into the device to accelerate the fluorescent labeling reactions at optimized flow rates (i.e. 1 and 20 {mu}L/min, respectively). After 2 min washing for each assay, the whole process could be finished within 30 min, with minimum consumption of labeling reagents and superior fluorescent signal intensity. The choice of QDs 525 for IFA resulted in bright and stable fluorescent signal, with minimum interference with the Cy3 signal from FISH detection.

  15. A NOVEL TECHNIQUE FOR MULTIPLE FAULTS AND THEIR LOCATIONS DETECTION AND START ELECTRODE SELECTION IN MICROFLUIDIC DIGITAL BIOCHIP

    Directory of Open Access Journals (Sweden)

    MUKTA MAJUMDER

    2013-10-01

    Full Text Available A device, that is used for biomedical operation or safety-critical applications like point-of-care health assessment, massive parallel DNA analysis, automated drug discovery, air-quality monitoring and food-safety testing, must have the attributes like reliability, dependability and correctness. As the biochips are used for these purposes; therefore, these devices must be fault free all the time. Naturally before using these chips, they must be well tested. We are proposing a novel technique that can detect multiple faults, locate the fault positions within the biochip, as well as calculate the traversal time if the biochip is fault free. The proposed technique also highlights a new idea how to select the appropriate base node or pseudo source (start electrode. The main idea of the proposed technique is to form multiple loops with the neighboring electrode arrays and then test each loop by traversing test droplet to check whether there is any fault. If a fault is detected then the proposed technique also locates it by backtracking the test droplet. In case, no fault is detected, the biochip is fault free then the proposed technique also calculates the time to traverse the chip. The result suggests that the proposed technique is efficient and shows significant improvement to calculate fault-free biochip traversal time over existing method.

  16. Recent Advances and Future Perspectives on Microfluidic Liquid Handling

    Directory of Open Access Journals (Sweden)

    Nam-Trung Nguyen

    2017-06-01

    Full Text Available The interdisciplinary research field of microfluidics has the potential to revolutionize current technologies that require the handling of a small amount of fluid, a fast response, low costs and automation. Microfluidic platforms that handle small amounts of liquid have been categorised as continuous-flow microfluidics and digital microfluidics. The first part of this paper discusses the recent advances of the two main and opposing applications of liquid handling in continuous-flow microfluidics: mixing and separation. Mixing and separation are essential steps in most lab-on-a-chip platforms, as sample preparation and detection are required for a variety of biological and chemical assays. The second part discusses the various digital microfluidic strategies, based on droplets and liquid marbles, for the manipulation of discrete microdroplets. More advanced digital microfluidic devices combining electrowetting with other techniques are also introduced. The applications of the emerging field of liquid-marble-based digital microfluidics are also highlighted. Finally, future perspectives on microfluidic liquid handling are discussed.

  17. Microfluidic stretchable RF electronics.

    Science.gov (United States)

    Cheng, Shi; Wu, Zhigang

    2010-12-07

    Stretchable electronics is a revolutionary technology that will potentially create a world of radically different electronic devices and systems that open up an entirely new spectrum of possibilities. This article proposes a microfluidic based solution for stretchable radio frequency (RF) electronics, using hybrid integration of active circuits assembled on flex foils and liquid alloy passive structures embedded in elastic substrates, e.g. polydimethylsiloxane (PDMS). This concept was employed to implement a 900 MHz stretchable RF radiation sensor, consisting of a large area elastic antenna and a cluster of conventional rigid components for RF power detection. The integrated radiation sensor except the power supply was fully embedded in a thin elastomeric substrate. Good electrical performance of the standalone stretchable antenna as well as the RF power detection sub-module was verified by experiments. The sensor successfully detected the RF radiation over 5 m distance in the system demonstration. Experiments on two-dimensional (2D) stretching up to 15%, folding and twisting of the demonstrated sensor were also carried out. Despite the integrated device was severely deformed, no failure in RF radiation sensing was observed in the tests. This technique illuminates a promising route of realizing stretchable and foldable large area integrated RF electronics that are of great interest to a variety of applications like wearable computing, health monitoring, medical diagnostics, and curvilinear electronics.

  18. Rapid detection of genetic modification for GMO monitoring in agriculture

    Directory of Open Access Journals (Sweden)

    Petrović Sofija

    2015-01-01

    Full Text Available Transgenic technology has expanded the ways of new genetic variability creation. Genetically modified organisms (GMOs are organisms which total genome is altered in a way that could not happen in nature. GM crops recorded a steady increase in its share in agricultural production. However, for the most part, GMO in agriculture has been limited to two cultivars - soy and corn, and the two genetic modifications, the total herbicide resistance and pest of the Lepidoptera genus. In order to monitor cultivation and trade of GMOs, tests of different precision are used, qualitatively and/or quantitatively determining the presence of genetic modification. Tests for the rapid determination of the presence of GM are suitable, since they can be implemented quickly and accurately, in terms of declared sensitivity, outside or in the laboratory. The example of the use of rapid tests demonstrates their value in use for rapid and efficient monitoring.

  19. In-Channel-Grown Polypyrrole Nanowire for the Detection of DNA Hybridization in an Electrochemical Microfluidic Biosensor

    Directory of Open Access Journals (Sweden)

    Thi Luyen Tran

    2015-01-01

    Full Text Available A triple electrode setup with a Pt pseudo-reference electrode integrated in a polydimethylsiloxane- (PDMS- based microchamber was designed and fabricated. The integrated electrodes were deposited onto SiO2/Si substrate by sputtering. The PDMS microchamber was patterned using an SU-8 mold and sealed with electrodes in oxygen plasma. Polypyrrole nanowires (PPy NWs were electrochemically grown in situ at an accurate position of the working electrode in the sealed microchamber instead of in an open system. The DNA probe sequences were simply introduced into the channel to form bonds with the nanowires. A detection limit of 20 pM was achieved using a lock-in amplifier. The electrochemical characteristics produced by the hybridization of DNA strands in the microchamber showed a good signal/noise ratio and high sensitivity. Measurement of the DNA sensor in narrow space also required much less volume of the analytical sample compared with that in an open measuring cell. Results showed that this simple system can potentially fabricate nanostructures and detect bio/chemical molecules in a sealed system.

  20. Microfluidic Formation of Membrane-Free Aqueous Coacervate Droplets in Water.

    Science.gov (United States)

    van Swaay, Dirk; Tang, T-Y Dora; Mann, Stephen; de Mello, Andrew

    2015-07-13

    We report on the formation of coacervate droplets from poly(diallyldimethylammonium chloride) with either adenosine triphosphate or carboxymethyl-dextran using a microfluidic flow-focusing system. The formed droplets exhibit improved stability and narrower size distributions for both coacervate compositions when compared to the conventional vortex dispersion techniques. We also demonstrate the use of two parallel flow-focusing channels for the simultaneous formation and co-location of two distinct populations of coacervate droplets containing different DNA oligonucleotides, and that the populations can coexist in close proximity up to 48 h without detectable exchange of genetic information. Our results show that the observed improvements in droplet stability and size distribution may be scaled with ease. In addition, the ability to encapsulate different materials into coacervate droplets using a microfluidic channel structure allows for their use as cell-mimicking compartments.

  1. Microfluidics for research and applications in oncology.

    Science.gov (United States)

    Chaudhuri, Parthiv Kant; Ebrahimi Warkiani, Majid; Jing, Tengyang; Kenry; Lim, Chwee Teck

    2016-01-21

    Cancer is currently one of the top non-communicable human diseases, and continual research and developmental efforts are being made to better understand and manage this disease. More recently, with the improved understanding in cancer biology as well as the advancements made in microtechnology and rapid prototyping, microfluidics is increasingly being explored and even validated for use in the detection, diagnosis and treatment of cancer. With inherent advantages such as small sample volume, high sensitivity and fast processing time, microfluidics is well-positioned to serve as a promising platform for applications in oncology. In this review, we look at the recent advances in the use of microfluidics, from basic research such as understanding cancer cell phenotypes as well as metastatic behaviors to applications such as the detection, diagnosis, prognosis and drug screening. We then conclude with a future outlook on this promising technology.

  2. Unconventional microfluidics: expanding the discipline.

    Science.gov (United States)

    Nawaz, Ahmad Ahsan; Mao, Xiaole; Stratton, Zackary S; Huang, Tony Jun

    2013-04-21

    Since its inception, the discipline of microfluidics has been harnessed for innovations in the biomedicine/chemistry fields-and to great effect. This success has had the natural side-effect of stereotyping microfluidics as a platform for medical diagnostics and miniaturized lab processes. But microfluidics has more to offer. And very recently, some researchers have successfully applied microfluidics to fields outside its traditional domains. In this Focus article, we highlight notable examples of such "unconventional" microfluidics applications (e.g., robotics, electronics). It is our hope that these early successes in unconventional microfluidics prompt further creativity, and inspire readers to expand the microfluidics discipline.

  3. Design and Fabrication of a PMMA Microfluidic Detection Chip%PMMA微流控检测芯片的设计与制作

    Institute of Scientific and Technical Information of China (English)

    唐飞; 王晓浩; 杨波

    2009-01-01

    设计并制作了一种PMMA(polymethyl methacrylate)材料的微流控检测芯片,将外界气体驱动液体用于实际水样的分析和检测.利用精密加工的方法加工出芯片的整体尺寸为86 mm×60 mm×4.5 mm.采用溶胶-凝胶的改性方法对微通道管路进行亲水处理,正硅酸乙酯的水解缩合生成了一层溶胶-凝胶覆盖在PMMA表面,从而大大提高了亲水性.在室温下对芯片进行键合,溶剂为二氯乙烷和无水乙醇按1:1混合的混合液.该方法避免了微通道的坍塌,有效防止了堵塞.实验证明,芯片接触紧密,且冲击强度能够满足要求.同时,芯片上集成了多个阀.阀膜选用0.5 mm厚的硅胶膜,采用硅橡胶做黏合剂.%A microfluidic detection chip with polymethyl methacrylate(PMMA) was designed and fabricated in this paper to analyze and detect water sample which, as liquid, was driven by external gas. The dimension of the chip is 86 mm×60 mm×4.5 mm, fabricated by the method of precision machining. By a kind of sol-gel method, the hydrolytic condensation reaction of ethyl silicate enables a layer of sol-gel to cover on PMMA surface so that the hydrophilic property in micro tube is improved remarkably. The chip was bonded at room temperature by the solvent bonding method with the solvent of dichloroethane-alcohol mixed in proportion of 1 : 1. Collapse and blockage of the micro tube were avoided, in addition, no leakage was found yet. Experimental results prove the chip's contact compact enough to enable the impact strength to meet the requirement. Meanwhile, several valves are integrated on the chip. Silica gel membrane with 0.5 mm in thickness used for the valve membrane is bonded together with the PMMA using silicone rubber.

  4. Facile Droplet-based Microfluidic Synthesis of Monodisperse IV-VI Semiconductor Nanocrystals with Coupled In-Line NIR Fluorescence Detection

    NARCIS (Netherlands)

    Lignos, Ioannis; Protesescu, Loredana; Stavrakis, Stavros; Piveteau, Laura; Speirs, Mark J.; Loi, Maria A.; Kovalenko, Maksym V.; deMello, Andrew J.

    2014-01-01

    We describe the realization of a droplet-based microfluidic platform for the controlled and reproducible synthesis of lead chalcogenide (PbS, PbSe) nanocrystal quantum dots (QDs). Monodisperse nanocrystals were synthesized over a wide range of experimental conditions, with real-time assessment and f

  5. Lab-on-chip system combining a microfluidic-ELISA with an array of amorphous silicon photosensors for the detection of celiac disease epitopes

    Directory of Open Access Journals (Sweden)

    Francesca Costantini

    2015-12-01

    The correct operation of the developed lab-on-chip has been demonstrated using rabbit serum in the microfluidic ELISA. In particular, optimizing the dilution factors of both sera and Ig-HRP samples in the flowing solutions, the specific and non-specific antibodies against GPs can be successfully distinguished, showing the suitability of the presented device to effectively screen celiac disease epitopes.

  6. From sample-to-answer: integrated genotyping and immunological analysis microfluidic platforms for the diagnostic and treatment of coeliac disease

    Science.gov (United States)

    Jung, M.; Höth, J.; Erwes, J.; Latta, D.; Strobach, X.; Hansen-Hagge, T.; Klemm, R.; Gärtner, C.; Demiris, T. M.; O'Sullivan, C.; Ritzi-Lehnert, M.; Drese, K. S.

    2011-02-01

    Taking advantage of microfluidics technology, a Lab-on-Chip system was developed offering the possibility of performing HLA (Human Leukocyte Antigen) typing to test genetic predisposition to coeliac disease and measure the level of immunodeficiency at the point-of-care. These analysis procedures are implemented on two different microfluidic cartridges, both having identical interfacial connections to the identical automated instrument. In order to assess the concentration of the targeted analytes in human blood, finger prick samples are processed to either extract genomic DNA carrying the coeliac disease gene or blood plasma containing the disease specific antibodies. We present here the different microfluidic modules integrated in a common platform, capable of automated sample preparation and analyte detection. In summary, this new microfluidic approach will dramatically reduce the costs of materials (polymer for the disposable chips and minute amount of bio-reagents) and minimize the time for analysis down to less than 20 minutes. In comparison to the state of the art detection of coeliac disease this work represents a tremendous improvement for the patient's quality of live and will significantly reduce the cost burden on the health care system.

  7. Integration of microfluidics into the synthetic biology design flow.

    Science.gov (United States)

    Huang, Haiyao; Densmore, Douglas

    2014-09-21

    One goal of synthetic biology is to design and build genetic circuits in living cells for a range of applications. Major challenges in these efforts include increasing the scalability and robustness of engineered biological systems and streamlining and automating the synthetic biology workflow of specification-design-assembly-verification. We present here a summary of the advances in microfluidic technology, particularly microfluidic large scale integration, that can be used to address the challenges facing each step of the synthetic biology workflow. Microfluidic technologies allow precise control over the flow of biological content within microscale devices, and thus may provide more reliable and scalable construction of synthetic biological systems. The integration of microfluidics and synthetic biology has the capability to produce rapid prototyping platforms for characterization of genetic devices, testing of biotherapeutics, and development of biosensors.

  8. Design of a microfluidic chip based real-time detection system for chemical pollutants%一种化学污染物微流控芯片实时检测系统的设计

    Institute of Scientific and Technical Information of China (English)

    邹志云; 刘兴红; 周世坤; 朱文超; 桂新军; 郑国芝

    2012-01-01

    A microfluidic chip based chemical pollutants real-time detection system is designed according to the rapid real-time environmental pollution detection requirements for chemical accident in site rescue and disposal. Both overall design and detailed design of the detection system is presented. The main key technology and their corresponding research strategy for the design of the microfluidic chip based detection system is discussed, including complex sample pretreatment technology especially solid phase extraction (SPE), rapid and sensitive detection technology, simulation, design, integration and control technology, and the hardware design and software programming of portable microfluidic chip based analysis instrument. The main research task and their related technological roadmap for the design and test of microfluidic chip based separation and detection unit, complex sample pretreatment unit, the development and test of prototype system, and the building of analysis knowledge base and database is explored. Through the scientific design of sample pretreatment unit, mixing unit, separation unit, detection unit, control unit and information treatment unit, a high integrative, portable, miniature microfluidic chip based analysis and detection system could be successfully designed for the analysis and detection of environmental chemical pollutants.%根据化学事故应急救援与处置现场环境污染快速、实时检测需要,提出了一种化学污染物微流控芯片实时检测系统的设计方案,进行了系统的总体设计和细化设计,论述了系统设计涉及的复杂基质样品微流控芯片预处理技术,特别是固相萃取样品预处理技术、快速灵敏的微流控芯片检测技术、微流控芯片的模拟仿真、设计、集成与控制技术,以及便携式微流控芯片分析仪器的硬件设计和软件开发技术等关键技术及其研究方法,探讨了微流控芯片分离与检测单元的设计与实验、复杂

  9. The Detection of Genetically Modified Organisms: An Overview

    Science.gov (United States)

    Ovesná, Jaroslava; Demnerová, Kateřina; Pouchová, Vladimíra

    Genetically modified organisms (GMOs) are those whose genetic material has been altered by the insertion of a new gene or by the deletion of an existing one(s). Modern biotechnology, in particular, the rise of genetic engineering, has supported the development of GMOs suitable for research purposes and practical applications (Gepts, 2002; Novoselova,Meuwissen, & Huirne, 2007; Sakakibara & Saito, 2006). For over 20 years GM bacteria and other GM organisms have been used in laboratories for the study of gene functions (Maliga & Small, 2007; Ratledge & Kristiansen, 2006). Agricultural plants were the first GMOs to be released into the environment and placed on the market. Farmers around the world use GMsoybeans, GMcorn and GM cotton that are herbicide tolerant, or insect resistant, or combine several traits that reduce the costs associated with crop production (Corinne, Fernandez-Cornejo, & Goodhue, 2004).

  10. Group 6 Layered Transition-Metal Dichalcogenides in Lab-on-a-Chip Devices: 1T-Phase WS2 for Microfluidics Non-Enzymatic Detection of Hydrogen Peroxide.

    Science.gov (United States)

    Toh, Rou Jun; Mayorga-Martinez, Carmen C; Han, Jongyoon; Sofer, Zdenek; Pumera, Martin

    2017-05-02

    Two-dimensional (2D) layered transition-metal dichalcogenides (TMDs) have been placed in the spotlight for their advantageous properties for catalytic and sensing applications. However, little work is done to explore and exploit them in enhancing the performance of analytical lab-on-a-chip (LOC) devices. In this work, we demonstrate a simple, sensitive, and low-cost fabrication of electrochemical LOC microfluidic devices to be used for enzymatic detection. We integrated four t-BuLi exfoliated, group 6 TMD materials (MoS2, MoSe2, WS2, and WSe2) within the LOC devices by the drop-casting method and compared their performance for H2O2 detection. The 1T-phase WS2-based LOC device outperformed the rest of the TMD materials and exhibited a wide range of linear response (20 nM to 20 μM and 100 μM to 2 mM), low detection limit (2.0 nM), and good selectivity for applications in real sample analysis. This work may facilitate the expanded use of electrochemical LOC microfluidics, with its easier integrability, for applications in the field of biodiagnostics and sensing.

  11. A Domain-Independent Window Approach to Multiclass Object Detection Using Genetic Programming

    Directory of Open Access Journals (Sweden)

    Mengjie Zhang

    2003-07-01

    Full Text Available This paper describes a domain-independent approach to the use of genetic programming for object detection problems in which the locations of small objects of multiple classes in large images must be found. The evolved program is scanned over the large images to locate the objects of interest. The paper develops three terminal sets based on domain-independent pixel statistics and considers two different function sets. The fitness function is based on the detection rate and the false alarm rate. We have tested the method on three object detection problems of increasing difficulty. This work not only extends genetic programming to multiclass-object detection problems, but also shows how to use a single evolved genetic program for both object classification and localisation. The object classification map developed in this approach can be used as a general classification strategy in genetic programming for multiple-class classification problems.

  12. Rapid Fabrication of Hydrogel Microfluidic Chip and Its Application for Cell Metabolites Detection%水凝胶微流控芯片的快速加工及在细胞培养检测中的应用

    Institute of Scientific and Technical Information of China (English)

    霍丹群; 方可敬; 侯长军; 杨眉; 法焕宝; 黄承洪; 罗小刚

    2013-01-01

    Taking advantage of the ultraviolet polymerization characteristic of poly(ethylene glycol) diacrylate (PEGDA) hydrogel material,a double-layer hydrogel microfluidic chip was fabricated rapidly by photopoly-merization method.Moreover,feasibility of the chip culture for tumor cell metabolism detection was validated.The hydrogel material with better biocompatibility and handleability compared to traditional microfluidic chip material could be directly processed to obtain desirable micro-structure.The experimental results showed that the proposed method could achieve the fabrication of double-layer cell culture and detection chip with short time treatment.Cells could be well captured and cultured in the hydrogel microfluidic chip with excellent activity.Chip integrated with porphyrin colorimetric sensor array system could effectively distinguish different types of tumor cell by metabolism characteristics detection.The hydrogel microfluidic chip has the potential of practicable application once large-scale preparation is accomplished.%采用具有紫外光聚合性能的聚乙二醇(PEG)基水凝胶材料,通过紫外光聚合作用快速加工双层水凝胶微流控芯片,并验证了其对肿瘤细胞代谢液进行检测的可行性.与传统微流控芯片材料相比,该水凝胶芯片材料具有更好的生物相容性及可操控性,可直接加工成形,在生物学领域特别是细胞培养过程控制方面具有良好的应用前景.实验结果表明,该水凝胶微流控芯片可在微尺度空间有效模拟细胞生长环境,并实现对细胞连续捕获后的原位培养.将该芯片与卟啉可视阵列传感器系统结合,经代谢特征分析可有效区分不同种类肿瘤细胞,实现芯片细胞培养平台上的细胞代谢指纹快速可视化传感检测.

  13. Comparison of genetic detection efficiency of different markers ...

    African Journals Online (AJOL)

    STORAGESEVER

    2009-06-03

    Jun 3, 2009 ... in phenotypic differences (Parra et al., 2003; Brutsaert et al., 2005) ... tion of neutral genetic variation among popula-tions, and ... relationship among breeds and exploring the evolution .... was not only related with their origin, but also related with ... National High Technology Research and Development.

  14. Structural chromosomal anomalies detected by prenatal genetic diagnosis: our experience.

    Science.gov (United States)

    Farcaş, Simona; Crişan, C D; Andreescu, Nicoleta; Stoian, Monica; Motoc, A G M

    2013-01-01

    The prenatal diagnosis is currently widely spread and facilitates the acquiring of important genetic information about the fetus by a rate extremely accelerate and considered without precedent. In this paper, we like to present our experience concerning the genetic diagnosis and counseling offered for pregnancies in which a structural chromosomal aberration was found. The study group is formed by 528 prenatal samples of amniotic fluid and chorionic villi, received by our laboratory from 2006 through October 2012 for cytogenetic diagnosis. The appropriate genetic investigation was selected based on the indications for prenatal diagnosis. The cases with structural chromosomal anomalies and polymorphic variants were analyzed as regard to the maternal age, gestational age, referral indications and type of chromosomal anomaly found. A total number of 21 structural chromosomal anomalies and polymorphic variants were identified in the study group. Out of 21 structural chromosomal anomalies and polymorphic variants, six deletions and microdeletions, four situations with abnormal long "p" arm of acrocentric chromosomes, two duplications, two reciprocal translocations, two inversions, two additions, one Robertsonian translocation associating trisomy 13, one 9q heteromorphism and one complex chromosome rearrangement were noticed. To the best of our knowledge, this is the first Romanian study in which the diagnostic strategies and the management of the prenatal cases with structural rearrangements are presented. The data provided about the diagnosis strategy and the management of the prenatal cases with structural chromosomal anomalies represents a useful tool in genetic counseling of pregnancies diagnosed with rare structural chromosomal anomalies.

  15. Detected microsatellite polymorphisms in genetically altered inbred mouse strains.

    Science.gov (United States)

    Du, Xiaoyan; Cui, Jing; Wang, Chao; Huo, Xueyun; Lu, Jing; Li, Yichen; Chen, Zhenwen

    2013-08-01

    Microsatellites are 50-200 repetitive DNA sequences composed of 1- to 6-base-pair-long reiterative motifs within the genome. They are vulnerable to DNA modifications, such as recombination and/or integration, and are recognized as "sentinel" DNA. Our previous report indicated that the genotypes of the microsatellite loci could change from mono- to poly-morphisms (CMP) in gene knockout (KO) mice, implying that genetic modification induces microsatellite mutation. However, it is still unclear whether the random insertion of DNA fragments into mice genomes produced via transgene (Tg) or N-ethyl-N-nitrosourea (ENU) would also result in microsatellite mutations or microsatellite loci genotypes changes. This study was designed to find possible clues to answer this question. In brief, 198 microsatellite loci that were distributed among almost all of the chromosomes (except for the Y) were examined through polymerase chain reaction to screen possible CMPs in six Tg strains. First, for each strain, the microsatellite sequences of all loci were compared between Tg and the corresponding background strain to exclude genetic interference. Simultaneously, to exclude spontaneous mutation-related CMPs that might exist in the examined six strains, mice from five spontaneously mutated inbred strains were used as the negative controls. Additionally, the sequences of all loci in these spontaneous mutated mice were compared to corresponding genetic background controls. The results showed that 40 of the 198 (20.2%) loci were identified as having CMPs in the examined Tg mice strains. The CMP genotypes were either homozygous or heterozygous compared to the background controls. Next, we applied the 40 CMP positive loci in ENU-mutated mice and their corresponding background controls. After that, a general comparison of CMPs that exist among Tg, ENU-treated and KO mouse strains was performed. The results indicated that four (D11mit258, D13mit3, D14mit102 and DXmit172) of the 40 (10%) CMP

  16. Opto-Microfluidic Immunosensors: From Colorimetric to Plasmonic

    Directory of Open Access Journals (Sweden)

    Jie-Long He

    2016-02-01

    Full Text Available Optical detection has long been the most popular technique in immunosensing. Recent developments in the synthesis of luminescent probes and the fabrication of novel nanostructures enable more sensitive and efficient optical detection, which can be miniaturized and integrated with microfluidics to realize compact lab-on-a-chip immunosensors. These immunosensors are portable, economical and automated, but their sensitivity is not compromised. This review focuses on the incorporation and implementation of optical detection and microfluidics in immunosensors; it introduces the working principles of each optical detection technique and how it can be exploited in immunosensing. The recent progress in various opto-microfluidic immunosensor designs is described. Instead of being comprehensive to include all opto-microfluidic platforms, the report centers on the designs that are promising for point-of-care immunosensing diagnostics, in which ease of use, stability and cost-effective fabrication are emphasized.

  17. Recent Advances in Applications of Droplet Microfluidics

    Directory of Open Access Journals (Sweden)

    Wei-Lung Chou

    2015-09-01

    Full Text Available Droplet-based microfluidics is a colloidal and interfacial system that has rapidly progressed in the past decade because of the advantages of low fabrication costs, small sample volumes, reduced analysis durations, high-throughput analysis with exceptional sensitivity, enhanced operational flexibility, and facile automation. This technology has emerged as a new tool for many recently used applications in molecular detection, imaging, drug delivery, diagnostics, cell biology and other fields. Herein, we review recent applications of droplet microfluidics proposed since 2013.

  18. Microfluidics and the life sciences.

    Science.gov (United States)

    Becker, Holger; Gärtner, Claudia

    2012-01-01

    The field of microfluidics, often also referred to as "Lab-on-a-Chip" has made significant progress in the last 15 years and is an essential tool in the development of new products and protocols in the life sciences. This article provides a broad overview on the developments on the academic as well as the commercial side. Fabrication technologies for polymer-based devices are presented and a strategy for the development of complex integrated devices is discussed, together with an example on the use of these devices in pathogen detection.

  19. Punch Card Programmable Microfluidics

    CERN Document Server

    Korir, George

    2014-01-01

    Small volume fluid handling in single and multiphase microfluidics provides a promising strategy for efficient bio-chemical assays, low-cost point-of-care diagnostics and new approaches to scientific discoveries. However multiple barriers exist towards low-cost field deployment of programmable microfluidics. Incorporating multiple pumps, mixers and discrete valve based control of nanoliter fluids and droplets in an integrated, programmable manner without additional required external components has remained elusive. Combining the idea of punch card programming with arbitrary fluid control, here we describe a self-contained, hand-crank powered, multiplex and robust programmable microfluidic platform. A paper tape encodes information as a series of punched holes. A mechanical reader/actuator reads these paper tapes and correspondingly executes a series of operations onto a microfluidic chip coupled to the platform in a plug-and-play fashion. Enabled by the complexity of codes that can be represented by a series ...

  20. Microfluidics in inorganic chemistry.

    Science.gov (United States)

    Abou-Hassan, Ali; Sandre, Olivier; Cabuil, Valérie

    2010-08-23

    The application of microfluidics in chemistry has gained significant importance in the recent years. Miniaturized chemistry platforms provide controlled fluid transport, rapid chemical reactions, and cost-saving advantages over conventional reactors. The advantages of microfluidics have been clearly established in the field of analytical and bioanalytical sciences and in the field of organic synthesis. It is less true in the field of inorganic chemistry and materials science; however in inorganic chemistry it has mostly been used for the separation and selective extraction of metal ions. Microfluidics has been used in materials science mainly for the improvement of nanoparticle synthesis, namely metal, metal oxide, and semiconductor nanoparticles. Microfluidic devices can also be used for the formulation of more advanced and sophisticated inorganic materials or hybrids.

  1. Microfluidic chemical reaction circuits

    Science.gov (United States)

    Lee, Chung-cheng; Sui, Guodong; Elizarov, Arkadij; Kolb, Hartmuth C.; Huang, Jiang; Heath, James R.; Phelps, Michael E.; Quake, Stephen R.; Tseng, Hsian-rong; Wyatt, Paul; Daridon, Antoine

    2012-06-26

    New microfluidic devices, useful for carrying out chemical reactions, are provided. The devices are adapted for on-chip solvent exchange, chemical processes requiring multiple chemical reactions, and rapid concentration of reagents.

  2. Simple Plex™: A Novel Multi‐Analyte, Automated Microfluidic Immunoassay Platform for the Detection of Human and Mouse Cytokines and Chemokines

    OpenAIRE

    Aldo, Paulomi; Marusov, Gregory; Svancara, Danielle; David, James; Mor, Gil

    2016-01-01

    Problem Quantitative measurement of proteins in bodily fluids or cellular preparations is critical for the evaluation of biomarkers or the study of complex cellular processes. While immunoassays are the most common quantitative approach used so far, they are not practical for the evaluation of multiple proteins. Microfluidic technology allows a fine spatial control in immobilizing proteins and biomolecules inside microchannels, eliminating cross‐reactivity between competing analytes, and allo...

  3. Microfluidic Bead Suspension Hopper

    OpenAIRE

    Price, Alexander K.; MacConnell, Andrew B.; Paegel, Brian M.

    2014-01-01

    Many high-throughput analytical platforms, from next-generation DNA sequencing to drug discovery, rely on beads as carriers of molecular diversity. Microfluidic systems are ideally suited to handle and analyze such bead libraries with high precision and at minute volume scales; however, the challenge of introducing bead suspensions into devices before they sediment usually confounds microfluidic handling and analysis. We developed a bead suspension hopper that exploits sedimentation to load b...

  4. Punch Card Programmable Microfluidics

    OpenAIRE

    George Korir; Manu Prakash

    2014-01-01

    Small volume fluid handling in single and multiphase microfluidics provides a promising strategy for efficient bio-chemical assays, low-cost point-of-care diagnostics and new approaches to scientific discoveries. However multiple barriers exist towards low-cost field deployment of programmable microfluidics. Incorporating multiple pumps, mixers and discrete valve based control of nanoliter fluids and droplets in an integrated, programmable manner without additional required external component...

  5. Surface acoustic wave microfluidics.

    Science.gov (United States)

    Ding, Xiaoyun; Li, Peng; Lin, Sz-Chin Steven; Stratton, Zackary S; Nama, Nitesh; Guo, Feng; Slotcavage, Daniel; Mao, Xiaole; Shi, Jinjie; Costanzo, Francesco; Huang, Tony Jun

    2013-09-21

    The recent introduction of surface acoustic wave (SAW) technology onto lab-on-a-chip platforms has opened a new frontier in microfluidics. The advantages provided by such SAW microfluidics are numerous: simple fabrication, high biocompatibility, fast fluid actuation, versatility, compact and inexpensive devices and accessories, contact-free particle manipulation, and compatibility with other microfluidic components. We believe that these advantages enable SAW microfluidics to play a significant role in a variety of applications in biology, chemistry, engineering and medicine. In this review article, we discuss the theory underpinning SAWs and their interactions with particles and the contacting fluids in which they are suspended. We then review the SAW-enabled microfluidic devices demonstrated to date, starting with devices that accomplish fluid mixing and transport through the use of travelling SAW; we follow that by reviewing the more recent innovations achieved with standing SAW that enable such actions as particle/cell focusing, sorting and patterning. Finally, we look forward and appraise where the discipline of SAW microfluidics could go next.

  6. Genetic algorithm for flood detection and evacuation route planning

    Science.gov (United States)

    Gomes, Rahul; Straub, Jeremy

    2017-05-01

    A genetic-type algorithm is presented that uses satellite geospatial data to determine the most probable path to safety for individuals in a disaster area, where a traditional routing system cannot be used. The algorithm uses geological features and disaster information to determine the shortest safe path. It predicts how a flood can change a landform over time and uses this data to predict alternate routes. It also predicts safe routes in rural locations where GPS/map-based routing data is unavailable or inaccurate. Reflectance and a supervised classification algorithm are used and the output is compared with RFPI and PCR-GLOBWB data.

  7. Microfluidics:Rapid Diagnosis for Breast Cancer

    Institute of Scientific and Technical Information of China (English)

    Satvinder Panesar; Suresh Neethirajan

    2016-01-01

    Breast cancer affected 1.7 million people worldwide in 2012 and accounts for approximately 23.3% of all cancers diagnosed in women. The disease is characterized by a genetic mutation, either inherited or resulting from envi-ronmental factors, that causes uncontrollable cellular growth of breast tissue or adjacent tissues. Current means of diag-nosing this disease depend on the individual analyzing the results from bulky, highly technical, and expensive equipment that is not globally accessible. As a result, patients can go undiagnosed due to a lack of available equipment or be over-diagnosed due to human error. This review attempts to highlight current means of diagnosing breast cancer and critically analyze their effectiveness and usefulness in terms of patient survival. An alternative means based on microfluidics biomarker detection is then presented. This method can be considered as a primary screening tool for diagnosing breast cancer based on its robustness, high throughput, low energy requirements, and accessibility to the general public.

  8. [Application of microfluidics in aquatic environmental pollution analysis].

    Science.gov (United States)

    Wang, Hu; Wei, Jun-Feng; Zheng, Guo-Xia

    2014-04-01

    Recently, a new type of chip technology, microfluidics, has received global attention for its rapid analysis speed, low reagent consumption, small size and simple operation, etc. Based on a micro-channel network and supported by a Micro-Electro-Mechanic System (MEMS), this technology integrates all the functions of a laboratory into one small piece of chip, which is called "lab on the chip". This paper presented a brief introduction about microfluidics and its representative developments. Future prospects in the aspects of instrument miniaturization, system integration, chip materials, and detection techniques, as well as the implementation of microfluidics in aquatic environmental pollutant analysis were thoroughly discussed. Some problems faced now were put forward. With the rapid progress in the microfluidics, a universal low-cost microchip capable of high speed multi-channel detection and integrated with many kinds of detection methods would be the research focus in the future.

  9. 基于微流控芯片的循环肿瘤细胞的分离、检测技术%The Separation, Detection of Circulating Tumor Cells Based on Microfluidic Chip

    Institute of Scientific and Technical Information of China (English)

    刘侃; 张俊哲

    2014-01-01

    Circulating tumor cells (Circulating Tumor Cells, CTCs) is the primary tumor or metastasis shed into the peripheral blood circulating tumor cells, is a sign of tumor metastasis. Early diagnosis, CTCs contribute to cancer, judging curative effect of individualized treatment plan and prognosis diagnosis. With the continuous improvement of detection, CTCs detection has be-come a hot spot, the clinical study, microfluidic chip for its high throughput efficiency and low cost rapid development and wide-ly application of. The research on the latest CTCs detection method and the future development trends are reviewed, especially the analysis of microfluidic chip based microfluidics and nanotechnology is how to be applied to circulating tumor cell separation, enrichment and detection, evaluation of the advantages and disadvantages of each method, and discusses the difficulties and mode of circulating flow cell detection technology future.%循环肿瘤细胞(Circulating Tumor Cells,CTCs)是自肿瘤原发灶或转移灶脱落进入外周血液循环的肿瘤细胞,是肿瘤远处转移的标志。CTCs有助于癌症的早期诊断、判断疗效、个体化治疗方案制订及诊断预后。随着检测技术的不断改进,CTCs检测成为临床研究的热点,其中,微流控芯片以其高通量高效率以及低成本的特点迅速发展并被广泛研究应用。该课题对CTCs最新检测方法的研究以及未来的发展趋势进行综述,特别剖析结合微流体技术和纳米技术的微流控芯片是如何被应用于循环肿瘤细胞的分离、富集以及检测的,评估各种方法的优缺点,并探讨未来循环中流细胞检测技术的难点和方式。

  10. Genetic basis and detection of unintended effects in genetically modified crop plants

    NARCIS (Netherlands)

    Ladics, G.S.; Bartholomaeus, A.; Bregitzer, P.; Doerrer, N.G.; Gray, A.; Holzhauzer, T.; Jordan, M.; Keese, P.; Kok, E.J.; Macdonald, P.; Parrott, W.; Privalle, L.; Raybould, A.; Rhee, S.Y.; Rice, E.; Romeis, J.; Vaughn, J.; Wal, J.M.; Glenn, K.

    2015-01-01

    In January 2014, an international meeting sponsored by the International Life Sciences Institute/Health and Environmental Sciences Institute and the Canadian Food Inspection Agency titled “Genetic Basis of Unintended Effects in Modified Plants” was held in Ottawa, Canada, bringing together over 75 s

  11. Detection and traceability of genetically modified organisms in the food production chain.

    Science.gov (United States)

    Miraglia, M; Berdal, K G; Brera, C; Corbisier, P; Holst-Jensen, A; Kok, E J; Marvin, H J P; Schimmel, H; Rentsch, J; van Rie, J P P F; Zagon, J

    2004-07-01

    Both labelling and traceability of genetically modified organisms are current issues that are considered in trade and regulation. Currently, labelling of genetically modified foods containing detectable transgenic material is required by EU legislation. A proposed package of legislation would extend this labelling to foods without any traces of transgenics. These new legislations would also impose labelling and a traceability system based on documentation throughout the food and feed manufacture system. The regulatory issues of risk analysis and labelling are currently harmonised by Codex Alimentarius. The implementation and maintenance of the regulations necessitates sampling protocols and analytical methodologies that allow for accurate determination of the content of genetically modified organisms within a food and feed sample. Current methodologies for the analysis of genetically modified organisms are focused on either one of two targets, the transgenic DNA inserted- or the novel protein(s) expressed- in a genetically modified product. For most DNA-based detection methods, the polymerase chain reaction is employed. Items that need consideration in the use of DNA-based detection methods include the specificity, sensitivity, matrix effects, internal reference DNA, availability of external reference materials, hemizygosity versus homozygosity, extrachromosomal DNA, and international harmonisation. For most protein-based methods, enzyme-linked immunosorbent assays with antibodies binding the novel protein are employed. Consideration should be given to the selection of the antigen bound by the antibody, accuracy, validation, and matrix effects. Currently, validation of detection methods for analysis of genetically modified organisms is taking place. In addition, new methodologies are developed, including the use of microarrays, mass spectrometry, and surface plasmon resonance. Challenges for GMO detection include the detection of transgenic material in materials

  12. An Enhancement of the Replacement Steady State Genetic Algorithm for Intrusion Detection

    Directory of Open Access Journals (Sweden)

    Reyadh Naoum

    2014-06-01

    Full Text Available In these days, Internet and computer systems face many intrusions, thus for this purpose we need to build a detection or prevention security system. Intrusion Detection System (IDS is a system used to detect attacks, Steady State Genetic Algorithm (SSGA is applied to support IDS by supplying the rule pool with additional data, these data can be used in testing phase to detect the attacks. The main goal of this research is to enhance Replacement steady state genetic algorithm to detect intrusions. This enhancement has been achieved by comparing replacement methods. This research proved that the Triple Tournament Replacement is better than Binary Tournament Replacement to increase Detection Rate and there are no effects on False Positive Rate. In this research represent the results of DR equal 100% for three types of attack (DoS, Probe and R2T, and 53% for U2R.

  13. Prenetal Detection of Oral Clefts : Diagnostic, Genetic and Ethical Aspects

    NARCIS (Netherlands)

    Maarse, W.

    2015-01-01

    Since the introduction of routine prenatal screening with ultrasound in the Netherlands in 2007, parents are confronted with the diagnosis of oral cleft (OC) already during pregnancy. This imposed a new dimension in cleft care in the Netherlands. As a consequence to increasing prenatal detection rat

  14. Punch card programmable microfluidics.

    Science.gov (United States)

    Korir, George; Prakash, Manu

    2015-01-01

    Small volume fluid handling in single and multiphase microfluidics provides a promising strategy for efficient bio-chemical assays, low-cost point-of-care diagnostics and new approaches to scientific discoveries. However multiple barriers exist towards low-cost field deployment of programmable microfluidics. Incorporating multiple pumps, mixers and discrete valve based control of nanoliter fluids and droplets in an integrated, programmable manner without additional required external components has remained elusive. Combining the idea of punch card programming with arbitrary fluid control, here we describe a self-contained, hand-crank powered, multiplex and robust programmable microfluidic platform. A paper tape encodes information as a series of punched holes. A mechanical reader/actuator reads these paper tapes and correspondingly executes operations onto a microfluidic chip coupled to the platform in a plug-and-play fashion. Enabled by the complexity of codes that can be represented by a series of holes in punched paper tapes, we demonstrate independent control of 15 on-chip pumps with enhanced mixing, normally-closed valves and a novel on-demand impact-based droplet generator. We demonstrate robustness of operation by encoding a string of characters representing the word "PUNCHCARD MICROFLUIDICS" using the droplet generator. Multiplexing is demonstrated by implementing an example colorimetric water quality assays for pH, ammonia, nitrite and nitrate content in different water samples. With its portable and robust design, low cost and ease-of-use, we envision punch card programmable microfluidics will bring complex control of microfluidic chips into field-based applications in low-resource settings and in the hands of children around the world.

  15. Punch card programmable microfluidics.

    Directory of Open Access Journals (Sweden)

    George Korir

    Full Text Available Small volume fluid handling in single and multiphase microfluidics provides a promising strategy for efficient bio-chemical assays, low-cost point-of-care diagnostics and new approaches to scientific discoveries. However multiple barriers exist towards low-cost field deployment of programmable microfluidics. Incorporating multiple pumps, mixers and discrete valve based control of nanoliter fluids and droplets in an integrated, programmable manner without additional required external components has remained elusive. Combining the idea of punch card programming with arbitrary fluid control, here we describe a self-contained, hand-crank powered, multiplex and robust programmable microfluidic platform. A paper tape encodes information as a series of punched holes. A mechanical reader/actuator reads these paper tapes and correspondingly executes operations onto a microfluidic chip coupled to the platform in a plug-and-play fashion. Enabled by the complexity of codes that can be represented by a series of holes in punched paper tapes, we demonstrate independent control of 15 on-chip pumps with enhanced mixing, normally-closed valves and a novel on-demand impact-based droplet generator. We demonstrate robustness of operation by encoding a string of characters representing the word "PUNCHCARD MICROFLUIDICS" using the droplet generator. Multiplexing is demonstrated by implementing an example colorimetric water quality assays for pH, ammonia, nitrite and nitrate content in different water samples. With its portable and robust design, low cost and ease-of-use, we envision punch card programmable microfluidics will bring complex control of microfluidic chips into field-based applications in low-resource settings and in the hands of children around the world.

  16. Genetic characterization of feline bocavirus detected in cats in Japan.

    Science.gov (United States)

    Takano, Tomomi; Takadate, Yoshihiro; Doki, Tomoyoshi; Hohdatsu, Tsutomu

    2016-10-01

    Feline bocavirus (FBoV) has been classified into three genotypes (FBoV1-FBoV3). FBoVs are mainly detected in feces. In the present study, we collected rectal swabs from cats in Japan and examined the samples for the presence of FBoV. The FBoV infection rate was 9.9 % in 101 cats. No significant association was observed between FBoV infection and clinical symptoms. Based on the full-length NS1 protein, the three strains of FBoVs detected in the present study shared high homologies with the genotype 2 FBoV POR1 strain. This is the first study to report FBoV in Japan.

  17. Genetic basis and detection of unintended effects in genetically modified crop plants.

    Science.gov (United States)

    Ladics, Gregory S; Bartholomaeus, Andrew; Bregitzer, Phil; Doerrer, Nancy G; Gray, Alan; Holzhauser, Thomas; Jordan, Mark; Keese, Paul; Kok, Esther; Macdonald, Phil; Parrott, Wayne; Privalle, Laura; Raybould, Alan; Rhee, Seung Yon; Rice, Elena; Romeis, Jörg; Vaughn, Justin; Wal, Jean-Michel; Glenn, Kevin

    2015-08-01

    In January 2014, an international meeting sponsored by the International Life Sciences Institute/Health and Environmental Sciences Institute and the Canadian Food Inspection Agency titled "Genetic Basis of Unintended Effects in Modified Plants" was held in Ottawa, Canada, bringing together over 75 scientists from academia, government, and the agro-biotech industry. The objectives of the meeting were to explore current knowledge and identify areas requiring further study on unintended effects in plants and to discuss how this information can inform and improve genetically modified (GM) crop risk assessments. The meeting featured presentations on the molecular basis of plant genome variability in general, unintended changes at the molecular and phenotypic levels, and the development and use of hypothesis-driven evaluations of unintended effects in assessing conventional and GM crops. The development and role of emerging "omics" technologies in the assessment of unintended effects was also discussed. Several themes recurred in a number of talks; for example, a common observation was that no system for genetic modification, including conventional methods of plant breeding, is without unintended effects. Another common observation was that "unintended" does not necessarily mean "harmful". This paper summarizes key points from the information presented at the meeting to provide readers with current viewpoints on these topics.

  18. Enabling Microfluidics: From Clean Rooms to Makerspaces

    Science.gov (United States)

    2016-09-30

    e.g. detection , electric manipulation, inlets/outlets) 129 [31]. For example, Lafluer et al. used 3D-printed and paper substrates to develop an...preparation, sample analysis, and optical detection methods can be 272 designed synonymously in the same space for a potentially instrument-free sample-to...287 drug screening, sepsis diagnostics, and ultra-rare cell types), new innovations in microfluidics 288 have obviated some of the need for the

  19. Microfluidic enzymatic biosensing systems: A review.

    Science.gov (United States)

    Mross, Stefan; Pierrat, Sebastien; Zimmermann, Tom; Kraft, Michael

    2015-08-15

    Microfluidic biosensing systems with enzyme-based detection have been extensively studied in the last years owing to features such as high specificity, a broad range of analytes and a high degree of automation. This review gives an overview of the most important factors associated with these systems. In the first part, frequently used immobilization protocols such as physisorption and covalent bonding and detection techniques such as amperometry and fluorescence measurements are discussed with respect to effort, lifetime and measurement range. The Michaelis-Menten model describing the kinetics of enzymatic reactions, the role of redox mediators and the limitations of the linear measurement range of enzymatic sensors are introduced. Several possibilities of extending the linear measurement range in microfluidic systems such as diffusion-limiting membranes and the flow injection setup are presented. Regarding the integration of enzymes into microfluidic systems during the fabrication process, the constraints imposed by the biomolecules due to the limited usage of high temperatures and solvents are addressed. In the second part, the most common forms of enzyme integration into microfluidic systems, i.e. in channels and on electrodes, on microparticles, on paper and thread and as injected enzyme solutions, are reviewed, focusing on fabrication, applications and performance.

  20. Isothermal circular-strand-displacement polymerization of DNA and microRNA in digital microfluidic devices.

    Science.gov (United States)

    Giuffrida, Maria Chiara; Zanoli, Laura Maria; D'Agata, Roberta; Finotti, Alessia; Gambari, Roberto; Spoto, Giuseppe

    2015-02-01

    Nucleic-acid amplification is a crucial step in nucleic-acid-sequence-detection assays. The use of digital microfluidic devices to miniaturize amplification techniques reduces the required sample volume and the analysis time and offers new possibilities for process automation and integration in a single device. The recently introduced droplet polymerase-chain-reaction (PCR) amplification methods require repeated cycles of two or three temperature-dependent steps during the amplification of the nucleic-acid target sequence. In contrast, low-temperature isothermal-amplification methods have no need for thermal cycling, thus requiring simplified microfluidic-device features. Here, the combined use of digital microfluidics and molecular-beacon (MB)-assisted isothermal circular-strand-displacement polymerization (ICSDP) to detect microRNA-210 sequences is described. MicroRNA-210 has been described as the most consistently and predominantly upregulated hypoxia-inducible factor. The nmol L(-1)-pmol L(-1) detection capabilities of the method were first tested by targeting single-stranded DNA sequences from the genetically modified Roundup Ready soybean. The ability of the droplet-ICSDP method to discriminate between full-matched, single-mismatched, and unrelated sequences was also investigated. The detection of a range of nmol L(-1)-pmol L(-1) microRNA-210 solutions compartmentalized in nanoliter-sized droplets was performed, establishing the ability of the method to detect as little as 10(-18) mol of microRNA target sequences compartmentalized in 20 nL droplets. The suitability of the method for biological samples was tested by detecting microRNA-210 from transfected K562 cells.

  1. Kinetic ELISA in Microfluidic Channels

    Directory of Open Access Journals (Sweden)

    Debashis Dutta

    2011-06-01

    Full Text Available In this article, we describe the kinetic ELISA of Blue Tongue and Epizootic Hemorrhagic Disease viral antibodies in microfluidic channels by monitoring the rate of generation of the enzyme reaction product under static conditions. It has been shown that this format of the immunoassay allows very reliable quantitation of the target species using inexpensive glass microchips and a standard epifluorescence microscope system coupled to a CCD camera. For the viral antibodies assayed here, the limit of detection (LOD for the analyte concentration in our microchips was established to be 3–5 times lower than that obtained on commercial microwell plates using a fiftieth of the sample volume and less than a third of the incubation time. Our analyses further show that when compared to the end-point ELISA format, the kinetic mode of this assay yields an improvement in the LOD by over an order of magnitude in microfluidic devices. This benefit is primarily realized as the observed variation in the background fluorescence (signal at the start of the enzyme reaction period was significantly larger than that in the rate of signal generation upon repeating these assays in different microchannels/microchips. Because the kinetic ELISA results depend only on the latter quantity, the noise level in them was substantially lower compared to that in its end-point counterpart in which the absolute fluorescence measurements are of greater significance. While a similar benefit was also recorded through implementation of kinetic ELISAs on the microwell platform, the improvement in LOD registered in that system was not as significant as was observed in the case of microfluidic assays.

  2. Compact and controlled microfluidic mixing and biological particle capture

    Science.gov (United States)

    Ballard, Matthew; Owen, Drew; Mills, Zachary Grant; Hesketh, Peter J.; Alexeev, Alexander

    2016-11-01

    We use three-dimensional simulations and experiments to develop a multifunctional microfluidic device that performs rapid and controllable microfluidic mixing and specific particle capture. Our device uses a compact microfluidic channel decorated with magnetic features. A rotating magnetic field precisely controls individual magnetic microbeads orbiting around the features, enabling effective continuous-flow mixing of fluid streams over a compact mixing region. We use computer simulations to elucidate the underlying physical mechanisms that lead to effective mixing and compare them with experimental mixing results. We study the effect of various system parameters on microfluidic mixing to design an efficient micromixer. We also experimentally and numerically demonstrate that orbiting microbeads can effectively capture particles transported by the fluid, which has major implications in pre-concentration and detection of biological particles including various cells and bacteria, with applications in areas such as point-of-care diagnostics, biohazard detection, and food safety. Support from NSF and USDA is gratefully acknowledged.

  3. Liquid metal enabled microfluidics.

    Science.gov (United States)

    Khoshmanesh, Khashayar; Tang, Shi-Yang; Zhu, Jiu Yang; Schaefer, Samira; Mitchell, Arnan; Kalantar-Zadeh, Kourosh; Dickey, Michael D

    2017-03-14

    Several gallium-based liquid metal alloys are liquid at room temperature. As 'liquid', such alloys have a low viscosity and a high surface tension while as 'metal', they have high thermal and electrical conductivities, similar to mercury. However, unlike mercury, these liquid metal alloys have low toxicity and a negligible vapor pressure, rendering them much safer. In comparison to mercury, the distinguishing feature of these alloys is the rapid formation of a self-limiting atomically thin layer of gallium oxide over their surface when exposed to oxygen. This oxide layer changes many physical and chemical properties of gallium alloys, including their interfacial and rheological properties, which can be employed and modulated for various applications in microfluidics. Injecting liquid metal into microfluidic structures has been extensively used to pattern and encapsulate highly deformable and reconfigurable electronic devices including electrodes, sensors, antennas, and interconnects. Likewise, the unique features of liquid metals have been employed for fabricating miniaturized microfluidic components including pumps, valves, heaters, and electrodes. In this review, we discuss liquid metal enabled microfluidic components, and highlight their desirable attributes including simple fabrication, facile integration, stretchability, reconfigurability, and low power consumption, with promising applications for highly integrated microfluidic systems.

  4. Detection of Babesia bigemina in cattle of different genetic groups and in Rhipicephalus (Boophilus) microplus tick.

    Science.gov (United States)

    Oliveira, M C S; Oliveira-Sequeira, T C G; Regitano, L C A; Alencar, M M; Néo, T A; Silva, A M; Oliveira, H N

    2008-08-17

    Babesia bigemina infections were investigated in four genetic groups of beef cattle and in Rhipicephalus (Boophilus) microplus engorged female ticks. Blood samples and engorged female ticks were collected from 15 cows and 15 calves from each of the following genetic groups: Nelore, Angus x Nelore, Canchim x Nelore, and Simmental x Nelore. Microscopic examination of blood smears and tick hemolymph revealed that merozoites of B. bigemina (6/60) as well as kinetes of Babesia spp. (9/549) were only detected in samples (blood and ticks, respectively) originated from calves. PCR-based methods using primers for specific detection of B. bigemina revealed 100% infection in both calves and cows, regardless the genetic group. Tick infection was detected by nested-PCR amplifications showing that the frequency of B. bigemina was higher (P0.05).

  5. Single Cell Response to Time-dependent Stimuli using a Microfluidic Bioreactor

    Science.gov (United States)

    Johnson-Chavarria, Eric M.; Agrawal, Utsav; Tanyeri, Melikhan; Kuhlman, Thomas E.; Schroeder, Charles M.

    2014-03-01

    Cellular adaptation is critical for survival under uncertain or dynamic environmental conditions. Recent studies have reported the ability of biological systems to implement low-pass filters to distinguish high frequency noise in environmental stimuli from lower frequency input signals, yet we still lack a complete understanding of this phenomenon. In this work, we report a microfluidic-based platform for single cell analysis that provides dynamic control over periodic, time-dependent culture media. Single cells are confined in free solution by the sole action of gentle fluid flow, thereby enabling non-perturbative trapping of cells for long time scales. In this way, our microfluidic-based technique provides the ability to control external stimuli with precise methods while observing non-adherent cells over long timescales. Using this approach, we observed intranucleoid diffusion of genetic repressor proteins released from a chromosomal binding array. Overall, this microfluidic approach provides a direct method for sustaining periodic environmental conditions, measuring growth rates, and detecting gene expression of single cells in free solution. Funded by NIH Pathway to Independence (PI) Award, 4R00HG004183-03. This work was supported by the National Science Foundation through a Graduate Research Fellowship to Eric M. Johnson-Chavarria.

  6. Genetically modified bacteria as a tool to detect microscopic solid tumor masses with triggered release of a recombinant biomarker.

    Science.gov (United States)

    Panteli, Jan T; Forkus, Brittany A; Van Dessel, Nele; Forbes, Neil S

    2015-04-01

    Current tomographic methods of cancer detection have limited sensitivity and are unable to detect malignant masses smaller than half a centimeter in diameter. Mortality from tumor recurrence and metastatic disease would be reduced if small lesions could be detected earlier. To overcome this limitation, we created a detection system that combines the specificity of tumor-targeting bacteria with the sensitivity of a synthetic biomarker. Bacteria, specifically Salmonella, preferentially accumulate in tumors and microscopic metastases as small as five cell layers thick. To create tumor detecting bacteria, an attenuated strain of Salmonella was engineered to express and release the fluorescent protein ZsGreen. A single-layer antibody method was developed to measure low concentrations of ZsGreen. Engineered bacteria were administered to a microfluidic tumor-on-a-chip device to measure protein production. In culture, half of produced ZsGreen was released by viable bacteria at a rate of 87.6 fg bacterium(-1) h(-1). Single-layer antibody dots were able to detect bacterially produced ZsGreen at concentrations down to 4.5 ng ml(-1). Bacteria colonized in 0.12 mm(3) of tumor tissue in the microfluidic device released ZsGreen at a rate of 23.9 μg h(-1). This release demonstrates that ZsGreen readily diffuses through tissue and accumulates at detectable concentrations. Based on a mathematical pharmacokinetic model, the measured rate of release would enable detection of 0.043 mm(3) tumor masses, which is 2600 times smaller than the current limit of tomographic techniques. Tumor-detecting bacteria would provide a sensitive, minimally invasive method to detect tumor recurrence, monitor treatment efficacy, and identify the onset of metastatic disease.

  7. A Genetic Algorithm and Fuzzy Logic Approach for Video Shot Boundary Detection

    Directory of Open Access Journals (Sweden)

    Dalton Meitei Thounaojam

    2016-01-01

    Full Text Available This paper proposed a shot boundary detection approach using Genetic Algorithm and Fuzzy Logic. In this, the membership functions of the fuzzy system are calculated using Genetic Algorithm by taking preobserved actual values for shot boundaries. The classification of the types of shot transitions is done by the fuzzy system. Experimental results show that the accuracy of the shot boundary detection increases with the increase in iterations or generations of the GA optimization process. The proposed system is compared to latest techniques and yields better result in terms of F1score parameter.

  8. A Genetic Algorithm and Fuzzy Logic Approach for Video Shot Boundary Detection.

    Science.gov (United States)

    Thounaojam, Dalton Meitei; Khelchandra, Thongam; Manglem Singh, Kh; Roy, Sudipta

    2016-01-01

    This paper proposed a shot boundary detection approach using Genetic Algorithm and Fuzzy Logic. In this, the membership functions of the fuzzy system are calculated using Genetic Algorithm by taking preobserved actual values for shot boundaries. The classification of the types of shot transitions is done by the fuzzy system. Experimental results show that the accuracy of the shot boundary detection increases with the increase in iterations or generations of the GA optimization process. The proposed system is compared to latest techniques and yields better result in terms of F1score parameter.

  9. Detection of genetically modified soybean in crude soybean oil.

    Science.gov (United States)

    Nikolić, Zorica; Vasiljević, Ivana; Zdjelar, Gordana; Ðorđević, Vuk; Ignjatov, Maja; Jovičić, Dušica; Milošević, Dragana

    2014-02-15

    In order to detect presence and quantity of Roundup Ready (RR) soybean in crude oil extracted from soybean seed with a different percentage of GMO seed two extraction methods were used, CTAB and DNeasy Plant Mini Kit. The amplifications of lectin gene, used to check the presence of soybean DNA, were not achieved in all CTAB extracts of DNA, while commercial kit gave satisfactory results. Comparing actual and estimated GMO content between two extraction methods, root mean square deviation for kit is 0.208 and for CTAB is 2.127, clearly demonstrated superiority of kit over CTAB extraction. The results of quantification evidently showed that if the oil samples originate from soybean seed with varying percentage of RR, it is possible to monitor the GMO content at the first stage of processing crude oil.

  10. In situ detection of horizontal transfer of mobile genetic elements

    DEFF Research Database (Denmark)

    Haagensen, Janus Anders Juul; Hansen, Susse Kirkelund; Johansen, Tove;

    2002-01-01

    Plasmid transfer was investigated in microbial populations associated with different types of surfaces. The general strategy behind these investigations was to label the transferable plasmid with a gene encoding a fluorescent protein in order to make it a transfer reporter. This was achieved...... promoters (transfer reporters) it was thus possible to detect transfer events in situ and correlate these with either the location of donor and recipient cells or with the growth activity of the cells. In some cases, expression of unstable Gfp from a growth-controlled promoter, rrnB from Escherichia coli...... by fusing the reporter gene with a lac promoter expression cassette and combining this with a donor cell-associated lacI repressor cassette. After construction of a range of strains and plasmids with combinations of genes expressing fluorescent proteins from constitutive (cell tagging) or regulated...

  11. Microfluidic Sample Preparation for Immunoassays

    Energy Technology Data Exchange (ETDEWEB)

    Visuri, S; Benett, W; Bettencourt, K; Chang, J; Fisher, K; Hamilton, J; Krulevitch, P; Park, C; Stockton, C; Tarte, L; Wang, A; Wilson, T

    2001-08-09

    Researchers at Lawrence Livermore National Laboratory are developing means to collect and identify fluid-based biological pathogens in the forms of proteins, viruses, and bacteria. to support detection instruments, they are developing a flexible fluidic sample preparation unit. The overall goal of this Microfluidic Module is to input a fluid sample, containing background particulates and potentially target compounds, and deliver a processed sample for detection. They are developing techniques for sample purification, mixing, and filtration that would be useful to many applications including immunologic and nucleic acid assays. Many of these fluidic functions are accomplished with acoustic radiation pressure or dielectrophoresis. They are integrating these technologies into packaged systems with pumps and valves to control fluid flow through the fluidic circuit.

  12. Surface Sensitive Microfluidic Optomechanical Sensors

    CERN Document Server

    Kim, Kyu Hyun

    2014-01-01

    The microfluidic optomechanical resonator (uFOMR) based on a thin-walled glass capillary supports high Q-factor (>1000) mechanical modes in the presence of liquids. In this Letter, the sensitivity of the uFOMR to the surface change is studied by layer-by-layer removal of SiO2 molecules from the uFOMR inner surface using various concentrations of hydrofluoric acid solutions. A frequency downshift is observed with a sensitivity of 1.2 Hz/(pg/mm2), which translates to a surface density detection limit of 83 pg/mm2. This work opens a door to using the optomechanical mode for detection and characterization of molecules present near the resonator surface.

  13. Microfluidic Flame Barrier

    Science.gov (United States)

    Mungas, Gregory S. (Inventor); Fisher, David J. (Inventor); Mungas, Christopher (Inventor)

    2013-01-01

    Propellants flow through specialized mechanical hardware that is designed for effective and safe ignition and sustained combustion of the propellants. By integrating a micro-fluidic porous media element between a propellant feed source and the combustion chamber, an effective and reliable propellant injector head may be implemented that is capable of withstanding transient combustion and detonation waves that commonly occur during an ignition event. The micro-fluidic porous media element is of specified porosity or porosity gradient selected to be appropriate for a given propellant. Additionally the propellant injector head design integrates a spark ignition mechanism that withstands extremely hot running conditions without noticeable spark mechanism degradation.

  14. Detection and Genetic Characterization of Rabies Virus from Human Patients

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Saliva and blood were collected from two patients who had not received post exposure prophylaxis in the cities of Wenzhou and Xinning respectively. Both patients were confirmed as positive for rabies by detection of rabies virus specific nucleoprotein antibodies in the sera by Western Blot. However, rabies virus specific RNA was only identified in the saliva collected from the patient in Wenzhou. Furthermore, the isolate Zhejiang Wz0 (H) was obtained by inoculating one-day-old suckling mice. Both nucleoprotein (N) and glycoprotein (G) genes from the isolate were amplified by RT-PCR and sequenced. Phylogenetic analysis indicated that the isolate belonged to classic rabies virus, and shared a higher homology with the street viruses from dogs in the main endemic areas in China and the street virus from dogs in Indonesia than with other known strains. Further comparison of the deduced amino acid sequences between the isolate and the vaccine strains used in China showed that the virus had a higher level of homology with the vaccine strain CTN than with the other vaccine strains (3aG, PV, PM and ERA). In particular, amino acid residues substitutions located in antigenic site Ⅲ in the G protein, which could react with the neutralizing antibodies, were observed. These results suggested that the virus belonged to the classic rabies virus, and both N and G genes diverged from the current vaccine strains used in China at either the nucleotide or the amino acid level.

  15. Design of a DNA chip for detection of unknown genetically modified organisms (GMOs).

    Science.gov (United States)

    Nesvold, Håvard; Kristoffersen, Anja Bråthen; Holst-Jensen, Arne; Berdal, Knut G

    2005-05-01

    Unknown genetically modified organisms (GMOs) have not undergone a risk evaluation, and hence might pose a danger to health and environment. There are, today, no methods for detecting unknown GMOs. In this paper we propose a novel method intended as a first step in an approach for detecting unknown genetically modified (GM) material in a single plant. A model is designed where biological and combinatorial reduction rules are applied to a set of DNA chip probes containing all possible sequences of uniform length n, creating probes capable of detecting unknown GMOs. The model is theoretically tested for Arabidopsis thaliana Columbia, and the probabilities for detecting inserts and receiving false positives are assessed for various parameters for this organism. From a theoretical standpoint, the model looks very promising but should be tested further in the laboratory. The model and algorithms will be available upon request to the corresponding author.

  16. A Microfluidic Chip with Integrated Microelectrode for Real-time Dopamine Detection%一种用于多巴胺实时检测的集成微电极的微流控芯片

    Institute of Scientific and Technical Information of China (English)

    刘军山; 肖庆龙; 葛丹; 张洋洋; 张文珠; 徐征; 刘冲; 王立鼎

    2015-01-01

    设计并制作了一种用于多巴胺实时检测的集成微电极的微流控芯片。芯片由一片聚二甲基硅氧烷( PDMS)沟道片和一片玻璃电极片组成,在PDMS沟道片上集成了用作细胞培养室的主通道和用于培养基输送的两条侧通道,在玻璃电极片上集成了用于多巴胺实时检测的微电极。为了解决PDMS沟道片与硅模具之间的脱模困难问题,研究了一种新的脱模方法。建立了一种Au-Au-Au三电极体系,表现出了良好的电化学检测性能。以溶解在神经干细胞培养基中的多巴胺为测试样品,对芯片的性能进行了初步研究。多巴胺的检出限为3.92μmol/L,线性检测范围为10~500μmol/L,片间的检测重复精度小于4%。%A microfluidic chip with integrated microelectrode for real-time dopamine detection was designed and fabricated. The chip consisted of a polydimethylsiloxane ( PDMS) channel plate and a glass electrode plate. One central channel as the culture chamber of neural stem cells and two lateral channels for transport of the culture medium were integrated on the PDMS channel plate. Microelectrodes for real-time dopamine detection were integrated on the glass electrode plate. To solve the problem in demoulding the PDMS channel plate from the silicon mould, a novel demoulding method was developed. An Au-Au-Au three-electrode system was constructed, and it performed well in electrochemical detection. The performance of the microfluidic chip was primarily studied by detecting dopamine dissolved in the medium for the culture of neural stem cells. The limit of detection was 3. 92 μmol/L, the linear detection range was from 10 μmol/L to 500 μmol/L, and the detection reproducibility from different chips was less than 4%.

  17. Detection of Genetic Diversity in Synthetic Hexaploid Wheats Using Microsatellite Markers

    Institute of Scientific and Technical Information of China (English)

    CHEN Guo-yue; LI Li-hui

    2007-01-01

    Ninety-five synthetic hexaploid wheats(2n=6x=42,AABBDD)were analyzed using 45 microsatellite markers to investigate the potential genetic diversity in wheat breeding programs.A total of 326 alleles were detected by these microsatellite primer pairs,with an average of 6.65 alleles per locus.The polymorphic information content(PIC),Simpson index(SI),and genetic similarity(GS)coefficient showed that the D genome is of the highest genetic diversity among the A,B,and D genomes in the synthetic hexaploid wheats.The results also indicated that the synthetic hexaploid wheat is an efficient way to enrich wheat genetic backgrounds,especially to use the genetic variations of the D genome from Aegilops squarrosa for wheat improvement.The UPGMA dendogram,based on a similarity matrix by a simple matching coefficient algorithm,delineated the above accessions into 5 major clusters and was in accordance with the available pedigree information.The results demonstrated the utility of microsatellite markers in detecting DNA polymorphism and estimating genetic diversity.

  18. Nucleic acid amplification using microfluidic systems.

    Science.gov (United States)

    Chang, Chen-Min; Chang, Wen-Hsin; Wang, Chih-Hung; Wang, Jung-Hao; Mai, John D; Lee, Gwo-Bin

    2013-04-07

    In the post-human-genome-project era, the development of molecular diagnostic techniques has advanced the frontiers of biomedical research. Nucleic-acid-based technology (NAT) plays an especially important role in molecular diagnosis. However, most research and clinical protocols still rely on the manual analysis of individual samples by skilled technicians which is a time-consuming and labor-intensive process. Recently, with advances in microfluidic designs, integrated micro total-analysis-systems have emerged to overcome the limitations of traditional detection assays. These microfluidic systems have the capability to rapidly perform experiments in parallel and with a high-throughput which allows a NAT analysis to be completed in a few hours or even a few minutes. These features have a significant beneficial influence on many aspects of traditional biological or biochemical research and this new technology is promising for improving molecular diagnosis. Thus, in the foreseeable future, microfluidic systems developed for molecular diagnosis using NAT will become an important tool in clinical diagnosis. One of the critical issues for NAT is nucleic acid amplification. In this review article, recent advances in nucleic acid amplification techniques using microfluidic systems will be reviewed. Different approaches for fast amplification of nucleic acids for molecular diagnosis will be highlighted.

  19. Discrete elements for 3D microfluidics.

    Science.gov (United States)

    Bhargava, Krisna C; Thompson, Bryant; Malmstadt, Noah

    2014-10-21

    Microfluidic systems are rapidly becoming commonplace tools for high-precision materials synthesis, biochemical sample preparation, and biophysical analysis. Typically, microfluidic systems are constructed in monolithic form by means of microfabrication and, increasingly, by additive techniques. These methods restrict the design and assembly of truly complex systems by placing unnecessary emphasis on complete functional integration of operational elements in a planar environment. Here, we present a solution based on discrete elements that liberates designers to build large-scale microfluidic systems in three dimensions that are modular, diverse, and predictable by simple network analysis techniques. We develop a sample library of standardized components and connectors manufactured using stereolithography. We predict and validate the flow characteristics of these individual components to design and construct a tunable concentration gradient generator with a scalable number of parallel outputs. We show that these systems are rapidly reconfigurable by constructing three variations of a device for generating monodisperse microdroplets in two distinct size regimes and in a high-throughput mode by simple replacement of emulsifier subcircuits. Finally, we demonstrate the capability for active process monitoring by constructing an optical sensing element for detecting water droplets in a fluorocarbon stream and quantifying their size and frequency. By moving away from large-scale integration toward standardized discrete elements, we demonstrate the potential to reduce the practice of designing and assembling complex 3D microfluidic circuits to a methodology comparable to that found in the electronics industry.

  20. Open-source, community-driven microfluidics with Metafluidics.

    Science.gov (United States)

    Kong, David S; Thorsen, Todd A; Babb, Jonathan; Wick, Scott T; Gam, Jeremy J; Weiss, Ron; Carr, Peter A

    2017-06-07

    Microfluidic devices have the potential to automate and miniaturize biological experiments, but open-source sharing of device designs has lagged behind sharing of other resources such as software. Synthetic biologists have used microfluidics for DNA assembly, cell-free expression, and cell culture, but a combination of expense, device complexity, and reliance on custom set-ups hampers their widespread adoption. We present Metafluidics, an open-source, community-driven repository that hosts digital design files, assembly specifications, and open-source software to enable users to build, configure, and operate a microfluidic device. We use Metafluidics to share designs and fabrication instructions for both a microfluidic ring-mixer device and a 32-channel tabletop microfluidic controller. This device and controller are applied to build genetic circuits using standard DNA assembly methods including ligation, Gateway, Gibson, and Golden Gate. Metafluidics is intended to enable a broad community of engineers, DIY enthusiasts, and other nontraditional participants with limited fabrication skills to contribute to microfluidic research.

  1. Detecting Genetic Isolation in Human Populations: A Study of European Language Minorities

    Science.gov (United States)

    Capocasa, Marco; Battaggia, Cinzia; Anagnostou, Paolo; Montinaro, Francesco; Boschi, Ilaria; Ferri, Gianmarco; Alù, Milena; Coia, Valentina; Crivellaro, Federica; Bisol, Giovanni Destro

    2013-01-01

    The identification of isolation signatures is fundamental to better understand the genetic structure of human populations and to test the relations between cultural factors and genetic variation. However, with current approaches, it is not possible to distinguish between the consequences of long-term isolation and the effects of reduced sample size, selection and differential gene flow. To overcome these limitations, we have integrated the analysis of classical genetic diversity measures with a Bayesian method to estimate gene flow and have carried out simulations based on the coalescent. Combining these approaches, we first tested whether the relatively short history of cultural and geographical isolation of four “linguistic islands” of the Eastern Alps (Lessinia, Sauris, Sappada and Timau) had left detectable signatures in their genetic structure. We then compared our findings to previous studies of European population isolates. Finally, we explored the importance of demographic and cultural factors in shaping genetic diversity among the groups under study. A combination of small initial effective size and continued genetic isolation from surrounding populations seems to provide a coherent explanation for the diversity observed among Sauris, Sappada and Timau, which was found to be substantially greater than in other groups of European isolated populations. Simulations of micro-evolutionary scenarios indicate that ethnicity might have been important in increasing genetic diversity among these culturally related and spatially close populations. PMID:23418562

  2. Genetic variation in the vulnerable and endemic Monkey Puzzle tree, detected using RAPDs.

    Science.gov (United States)

    Bekessy, Sarah A; Allnutt, T R; Premoli, A C; Lara, A; Ennos, R A; Burgman, M A; Cortes, M; Newton, A C

    2002-04-01

    Araucaria araucana (Monkey Puzzle), a southern South American tree species of exceptional cultural and economic importance, is of conservation concern owing to extensive historical clearance and current human pressures. Random amplified polymorphic DNA (RAPD) markers were used to characterise genetic heterogeneity within and among 13 populations of this species from throughout its natural range. Extensive genetic variability was detected and partitioned by analysis of molecular variance, with the majority of variation existing within populations (87.2%), but significant differentiation was recorded among populations (12.8%). Estimates of Shannon's genetic diversity and percent polymorphism were relatively high for all populations and provide no evidence for a major reduction in genetic diversity from historical events, such as glaciation. All pairwise genetic distance values derived from analysis of molecular variance (Phi(ST)) were significant when individual pairs of populations were compared. Although populations are geographically divided into Chilean Coastal, Chilean Andes and Argentinean regions, this grouping explained only 1.77% of the total variation. Within Andean groups there was evidence of a trend of genetic distance with increasing latitude, and clustering of populations across the Andes, suggesting postglacial migration routes from multiple refugia. Implications of these results for the conservation and use of the genetic resource of this species are discussed.

  3. Quantitative PCR for Detection and Enumeration of Genetic Markers of Bovine Fecal Pollution

    Science.gov (United States)

    Accurate assessment of health risks associated with bovine (cattle) fecal pollution requires a reliable host-specific genetic marker and a rapid quantification method. We report the development of quantitative PCR assays for the detection of two recently described cow feces-spec...

  4. Surfactants in microfluidics

    NARCIS (Netherlands)

    Michler, D.

    2015-01-01

    The rapid development of microfluidic techniques in the last two decades has revolutionized chemical and biological research. This technology has enabled scientists in a manifold of research fields to analyze and synthesize specimens with hither to unreached speed and precision. The number of applic

  5. Basic Microfluidics Theory

    DEFF Research Database (Denmark)

    Svendsen, Winnie Edith

    2015-01-01

    ,000 m−1, which is a huge difference and has a large impact on flow behavior. In this chapter the basic microfluidic theory will be presented, enabling the reader to gain a comprehensive understanding of how liquids behave at the microscale, enough to be able to engage in design of micro systems...

  6. Microfluidics for medical applications

    NARCIS (Netherlands)

    van den Berg, Albert; van den Berg, A.; Segerink, L.I.; Segerink, Loes Irene; Unknown, [Unknown

    2015-01-01

    Lab-on-a-chip devices for point of care diagnostics have been present in clinics for several years now. Alongside their continual development, research is underway to bring the organs and tissue on-a-chip to the patient, amongst other medical applications of microfluidics. This book provides the

  7. Chemistry in Microfluidic Channels

    Science.gov (United States)

    Chia, Matthew C.; Sweeney, Christina M.; Odom, Teri W.

    2011-01-01

    General chemistry introduces principles such as acid-base chemistry, mixing, and precipitation that are usually demonstrated in bulk solutions. In this laboratory experiment, we describe how chemical reactions can be performed in a microfluidic channel to show advanced concepts such as laminar fluid flow and controlled precipitation. Three sets of…

  8. Characterization of Fluid Flow in Paper-Based Microfluidic Systems

    Science.gov (United States)

    Walji, Noosheen; MacDonald, Brendan

    2014-11-01

    Paper-based microfluidic devices have been presented as a viable low-cost alternative with the versatility to accommodate many applications in disease diagnosis and environmental monitoring. Current microfluidic designs focus on the use of silicone and PDMS structures, and several models have been developed to describe these systems; however, the design process for paper-based devices is hindered by a lack of prediction capability. In this work we simplify the complex underlying physics of the capillary-driven flow mechanism in a porous medium and generate a practical numerical model capable of predicting the flow behaviour. We present our key insights regarding the properties that dictate the behaviour of fluid wicking in paper-based microfluidic devices. We compare the results from our model to experiments and discuss the application of our model to design of paper-based microfluidic devices for arsenic detection in drinking water in Bangladesh.

  9. Cell mechanics through analysis of cell trajectories in microfluidic channel

    Science.gov (United States)

    Bowie, Samuel; Alexeev, Alexander; Sulchek, Todd

    The understanding of dynamic cell behavior can aid in research ranging from the mechanistic causes of diseases to the development of microfluidic devices for cancer detection. Through analysis of trajectories captured from video of the cells moving in a specially designed microfluidic device, insight into the dynamic viscoelastic nature of cells can be found. The microfluidic device distinguishes cells viscoelastic properties through the use of angled ridges causing a series of compressions, resulting in differences in trajectories based on cell stiffness. Trajectories of cell passing through the device are collected using image processing methods and data mining techniques are used to relate the trajectories to cell properties obtained from experiments. Furthermore, numerical simulation of the cell and microfluidic device are used to match the experimental results from the trajectory analysis. Combination of the modeling and experimental data help to uncover how changes in cellular structures result in changes in mechanical properties.

  10. Single-molecule emulsion PCR in microfluidic droplets.

    Science.gov (United States)

    Zhu, Zhi; Jenkins, Gareth; Zhang, Wenhua; Zhang, Mingxia; Guan, Zhichao; Yang, Chaoyong James

    2012-06-01

    The application of microfluidic droplet PCR for single-molecule amplification and analysis has recently been extensively studied. Microfluidic droplet technology has the advantages of compartmentalizing reactions into discrete volumes, performing highly parallel reactions in monodisperse droplets, reducing cross-contamination between droplets, eliminating PCR bias and nonspecific amplification, as well as enabling fast amplification with rapid thermocycling. Here, we have reviewed the important technical breakthroughs of microfluidic droplet PCR in the past five years and their applications to single-molecule amplification and analysis, such as high-throughput screening, next generation DNA sequencing, and quantitative detection of rare mutations. Although the utilization of microfluidic droplet single-molecule PCR is still in the early stages, its great potential has already been demonstrated and will provide novel solutions to today's biomedical engineering challenges in single-molecule amplification and analysis.

  11. High-throughput droplet analysis and multiplex DNA detection in the microfluidic platform equipped with a robust sample-introduction technique

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Jinyang; Ji, Xinghu [Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education), College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072 (China); He, Zhike, E-mail: zhkhe@whu.edu.cn [Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education), College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072 (China); Suzhou Institute of Wuhan University, Suzhou 215123 (China)

    2015-08-12

    In this work, a simple, flexible and low-cost sample-introduction technique was developed and integrated with droplet platform. The sample-introduction strategy was realized based on connecting the components of positive pressure input device, sample container and microfluidic chip through the tygon tubing with homemade polydimethylsiloxane (PDMS) adaptor, so the sample was delivered into the microchip from the sample container under the driving of positive pressure. This sample-introduction technique is so robust and compatible that could be integrated with T-junction, flow-focus or valve-assisted droplet microchips. By choosing the PDMS adaptor with proper dimension, the microchip could be flexibly equipped with various types of familiar sample containers, makes the sampling more straightforward without trivial sample transfer or loading. And the convenient sample changing was easily achieved by positioning the adaptor from one sample container to another. Benefiting from the proposed technique, the time-dependent concentration gradient was generated and applied for quantum dot (QD)-based fluorescence barcoding within droplet chip. High-throughput droplet screening was preliminarily demonstrated through the investigation of the quenching efficiency of ruthenium complex to the fluorescence of QD. More importantly, multiplex DNA assay was successfully carried out in the integrated system, which shows the practicability and potentials in high-throughput biosensing. - Highlights: • A simple, robust and low-cost sample-introduction technique was developed. • Convenient and flexible sample changing was achieved in microfluidic system. • Novel strategy of concentration gradient generation was presented for barcoding. • High-throughput droplet screening could be realized in the integrated platform. • Multiplex DNA assay was successfully carried out in the droplet platform.

  12. Cell-based bioassays in microfluidic systems

    Science.gov (United States)

    Itle, Laura J.; Zguris, Jeanna C.; Pishko, Michael V.

    2004-12-01

    The development of cell-based bioassays for high throughput drug screening or the sensing of biotoxins is contingent on the development of whole cell sensors for specific changes in intracellular conditions and the integration of those systems into sample delivery devices. Here we show the feasibility of using a 5-(and-6)-carboxy SNARF-1, acetoxymethyl ester, acetate, a fluorescent dye capable of responding to changes in intracellular pH, as a detection method for the bacterial endotoxin, lipopolysaccharide. We used photolithography to entrap cells with this dye within poly(ethylene) glyocol diacrylate hydrogels in microfluidic channels. After 18 hours of exposure to lipopolysaccharide, we were able to see visible changes in the fluorescent pattern. This work shows the feasibility of using whole cell based biosensors within microfluidic networks to detect cellular changes in response to exogenous agents.

  13. Genetics

    Science.gov (United States)

    ... Inheritance; Heterozygous; Inheritance patterns; Heredity and disease; Heritable; Genetic markers ... The chromosomes are made up of strands of genetic information called DNA. Each chromosome contains sections of ...

  14. Epigenetic-genetic chromosome dosage approach for fetal trisomy 21 detection using an autosomal genetic reference marker.

    Directory of Open Access Journals (Sweden)

    Yu K Tong

    Full Text Available BACKGROUND: The putative promoter of the holocarboxylase synthetase (HLCS gene on chromosome 21 is hypermethylated in placental tissues and could be detected as a fetal-specific DNA marker in maternal plasma. Detection of fetal trisomy 21 (T21 has been demonstrated by an epigenetic-genetic chromosome dosage approach where the amount of hypermethylated HLCS in maternal plasma is normalized using a fetal genetic marker on the Y chromosome as a chromosome dosage reference marker. We explore if this method can be applied on both male and female fetuses with the use of a paternally-inherited fetal single nucleotide polymorphism (SNP allele on a reference chromosome for chromosome dosage normalization. METHODOLOGY: We quantified hypermethylated HLCS molecules using methylation-sensitive restriction endonuclease digestion followed by real-time or digital PCR analyses. For chromosome dosage analysis, we compared the amount of digestion-resistant HLCS to that of a SNP allele (rs6636, a C/G SNP that the fetus has inherited from the father but absent in the pregnant mother. PRINCIPAL FINDINGS: Using a fetal-specific SNP allele on a reference chromosome, we analyzed 20 euploid and nine T21 placental tissue samples. All samples with the fetal-specific C allele were correctly classified. One sample from each of the euploid and T21 groups were misclassified when the fetal-specific G allele was used as the reference marker. We then analyzed 33 euploid and 14 T21 maternal plasma samples. All but one sample from each of the euploid and T21 groups were correctly classified using the fetal-specific C allele, while correct classification was achieved for all samples using the fetal-specific G allele as the reference marker. CONCLUSIONS: As a proof-of-concept study, we have demonstrated that the epigenetic-genetic chromosome dosage approach can be applied to the prenatal diagnosis of trisomy 21 for both male and female fetuses.

  15. Magnetic digital microfluidics - a review.

    Science.gov (United States)

    Zhang, Yi; Nguyen, Nam-Trung

    2017-03-14

    A digital microfluidic platform manipulates droplets on an open surface. Magnetic digital microfluidics utilizes magnetic forces for actuation and offers unique advantages compared to other digital microfluidic platforms. First, the magnetic particles used in magnetic digital microfluidics have multiple functions. In addition to serving as actuators, they also provide a functional solid substrate for molecule binding, which enables a wide range of applications in molecular diagnostics and immunodiagnostics. Second, magnetic digital microfluidics can be manually operated in a "power-free" manner, which allows for operation in low-resource environments for point-of-care diagnostics where even batteries are considered a luxury item. This review covers research areas related to magnetic digital microfluidics. This paper first summarizes the current development of magnetic digital microfluidics. Various methods of droplet manipulation using magnetic forces are discussed, ranging from conventional magnetic particle-based actuation to the recent development of ferrofluids and magnetic liquid marbles. This paper also discusses several new approaches that use magnetically controlled flexible substrates for droplet manipulation. In addition, we emphasize applications of magnetic digital microfluidics in biosensing and medical diagnostics, and identify the current limitations of magnetic digital microfluidics. We provide a perspective on possible solutions to close these gaps. Finally, the paper discusses the future improvement of magnetic digital microfluidics to explore potential new research directions.

  16. Detection of Genetically Modified Maize in Processed Foods Sold Commercially in Iran by Qualitative PCR

    Science.gov (United States)

    Rabiei, Maryam; Mehdizadeh, Mehrangiz; Rastegar, Hossein; Vahidi, Hossein; Alebouyeh, Mahmoud

    2013-01-01

    Detection of genetically modified organisms (GMOs) in food is an important issue for all the subjects involved in food control and customer’s right. Due to the increasing number of GMOs imported to Iran during the past few years, it has become necessary to screen the products in order to determine the identity of the consumed daily foodstuffs. In this study, following the extraction of genomic DNA from processed foods sold commercially in Iran, qualitative PCR was performed to detect genetically modified maize. The recombinant DNA target sequences were detected with primers highly specific for each investigated transgene such as CaMV35s gene, Bt-11, MON810 and Bt-176 separately. Based on the gel electrophoresis results, Bt- 11 and MON810 events were detected in some maize samples, while, in none of them Bt- 176 modified gene was detected. For the first time, the results demonstrate the presence of genetically modified maize in Iranian food products, reinforcing the need for the development of labeling system and valid quantitative methods in routine analyses. PMID:24250568

  17. Comparison of Bayesian clustering and edge detection methods for inferring boundaries in landscape genetics

    Science.gov (United States)

    Safner, T.; Miller, M.P.; McRae, B.H.; Fortin, M.-J.; Manel, S.

    2011-01-01

    Recently, techniques available for identifying clusters of individuals or boundaries between clusters using genetic data from natural populations have expanded rapidly. Consequently, there is a need to evaluate these different techniques. We used spatially-explicit simulation models to compare three spatial Bayesian clustering programs and two edge detection methods. Spatially-structured populations were simulated where a continuous population was subdivided by barriers. We evaluated the ability of each method to correctly identify boundary locations while varying: (i) time after divergence, (ii) strength of isolation by distance, (iii) level of genetic diversity, and (iv) amount of gene flow across barriers. To further evaluate the methods' effectiveness to detect genetic clusters in natural populations, we used previously published data on North American pumas and a European shrub. Our results show that with simulated and empirical data, the Bayesian spatial clustering algorithms outperformed direct edge detection methods. All methods incorrectly detected boundaries in the presence of strong patterns of isolation by distance. Based on this finding, we support the application of Bayesian spatial clustering algorithms for boundary detection in empirical datasets, with necessary tests for the influence of isolation by distance. ?? 2011 by the authors; licensee MDPI, Basel, Switzerland.

  18. Simultaneous Detection of Genetically Modified Organisms in a Mixture by Multiplex PCR-Chip Capillary Electrophoresis.

    Science.gov (United States)

    Patwardhan, Supriya; Dasari, Srikanth; Bhagavatula, Krishna; Mueller, Steffen; Deepak, Saligrama Adavigowda; Ghosh, Sudip; Basak, Sanjay

    2015-01-01

    An efficient PCR-based method to trace genetically modified food and feed products is in demand due to regulatory requirements and contaminant issues in India. However, post-PCR detection with conventional methods has limited sensitivity in amplicon separation that is crucial in multiplexing. The study aimed to develop a sensitive post-PCR detection method by using PCR-chip capillary electrophoresis (PCR-CCE) to detect and identify specific genetically modified organisms in their genomic DNA mixture by targeting event-specific nucleotide sequences. Using the PCR-CCE approach, novel multiplex methods were developed to detect MON531 cotton, EH 92-527-1 potato, Bt176 maize, GT73 canola, or GA21 maize simultaneously when their genomic DNAs in mixtures were amplified using their primer mixture. The repeatability RSD (RSDr) of the peak migration time was 0.06 and 3.88% for the MON531 and Bt176, respectively. The RSD (RSDR) of the Cry1Ac peak ranged from 0.12 to 0.40% in multiplex methods. The method was sensitive in resolving amplicon of size difference up to 4 bp. The PCR-CCE method is suitable to detect multiple genetically modified events in a composite DNA sample by tagging their event specific sequences.

  19. Pressure-driven microfluidic perfusion culture device for integrated dose-response assays.

    Science.gov (United States)

    Hattori, Koji; Sugiura, Shinji; Kanamori, Toshiyuki

    2013-12-01

    Cell-based assays are widely used in the various stages of drug discovery. Advances in microfluidic systems over the past two decades have enabled them to become a powerful tool for cell-based assays to achieve both reliability and high throughput. The interface between the micro-world and macro-world is important in industrial assay processes. Therefore, microfluidic cell-based assays using pressure-driven liquid handling are an ideal platform for integrated assays. The aim of this article is to review recent advancements in microfluidic cell-based assays focusing on a pressure-driven perfusion culture device. Here, we review the development of microfluidic cell-based assay devices and discuss the techniques involved in designing a microfluidic network, device fabrication, liquid and cell manipulation, and detection schemes for pressure-driven perfusion culture devices. Finally, we describe recent progress in semiautomatic and reliable pressure-driven microfluidic cell-based assays.

  20. Design of Fault-Tolerant and Dynamically-Reconfigurable Microfluidic Biochips

    CERN Document Server

    Su, Fei

    2011-01-01

    Microfluidics-based biochips are soon expected to revolutionize clinical diagnosis, DNA sequencing, and other laboratory procedures involving molecular biology. Most microfluidic biochips are based on the principle of continuous fluid flow and they rely on permanently-etched microchannels, micropumps, and microvalves. We focus here on the automated design of "digital" droplet-based microfluidic biochips. In contrast to continuous-flow systems, digital microfluidics offers dynamic reconfigurability; groups of cells in a microfluidics array can be reconfigured to change their functionality during the concurrent execution of a set of bioassays. We present a simulated annealing-based technique for module placement in such biochips. The placement procedure not only addresses chip area, but it also considers fault tolerance, which allows a microfluidic module to be relocated elsewhere in the system when a single cell is detected to be faulty. Simulation results are presented for a case study involving the polymeras...

  1. Optimized fabrication protocols of microfluidic devices for X-ray analysis

    KAUST Repository

    Catalano, Rossella

    2014-07-01

    Microfluidics combined with X-ray scattering techniques allows probing conformational changes or assembly processes of biological materials. Our aim was to develop a highly X-ray transparent microfluidic cell for detecting small variations of X-ray scattering involved in such processes. We describe the fabrication of a polyimide microfluidic device based on a simple, reliable and inexpensive lamination process. The implemented microstructured features result in windows with optimized X-ray transmission. The microfluidic device was characterized by X-ray microbeam scattering at the ID13 beamline of the European Synchrotron Radiation Facility. © 2014 Elsevier B.V. All rights reserved.

  2. Differential detection of genetic Loci underlying stem and root lignin content in Populus.

    Directory of Open Access Journals (Sweden)

    Tongming Yin

    Full Text Available In this study, we established a comprehensive genetic map with a large number of progeny from a three-generation hybrid Populus intercross, and phenotyped the lignin content, S/G ratio and 28 cell wall subcomponents both in stems and roots for the mapping individuals. Phenotypic analysis revealed that lignin content and syringyl-to-guaiacyl (S/G ratio using pyrolysis molecular beam mass spectroscopy (pyMBMS varied among mapping individuals. Phenotypic analysis revealed that stem lignin content is significantly higher than that in root and the quantified traits can be classified into four distinct groups, with strong correlations observed among components within organs. Altogether, 179 coordinating QTLs were detected, and they were co-localized into 49 genetic loci, 27 of which appear to be pleiotropic. Many of the detected genetic loci were detected differentially in stem and root. This is the first report of separate genetic loci controlling cell wall phenotypes above and below ground. These results suggest that it may be possible to modify lignin content and composition via breed and/or engineer as a means of simultaneously improving Populus for cellulosic ethanol production and carbon sequestration.

  3. Microfluidic Biosensing Systems Using Magnetic Nanoparticles

    Directory of Open Access Journals (Sweden)

    Franz Keplinger

    2013-09-01

    Full Text Available In recent years, there has been rapidly growing interest in developing hand held, sensitive and cost-effective on-chip biosensing systems that directly translate the presence of certain bioanalytes (e.g., biomolecules, cells and viruses into an electronic signal. The impressive and rapid progress in micro- and nanotechnology as well as in biotechnology enables the integration of a variety of analytical functions in a single chip. All necessary sample handling and analysis steps are then performed within the chip. Microfluidic systems for biomedical analysis usually consist of a set of units, which guarantees the manipulation, detection and recognition of bioanalytes in a reliable and flexible manner. Additionally, the use of magnetic fields for performing the aforementioned tasks has been steadily gaining interest. This is because magnetic fields can be well tuned and applied either externally or from a directly integrated solution in the biosensing system. In combination with these applied magnetic fields, magnetic nanoparticles are utilized. Some of the merits of magnetic nanoparticles are the possibility of manipulating them inside microfluidic channels by utilizing high gradient magnetic fields, their detection by integrated magnetic microsensors, and their flexibility due to functionalization by means of surface modification and specific binding. Their multi-functionality is what makes them ideal candidates as the active component in miniaturized on-chip biosensing systems. In this review, focus will be given to the type of biosening systems that use microfluidics in combination with magnetoresistive sensors and detect the presence of bioanalyte tagged with magnetic nanoparticles.

  4. Microfluidic biosensing systems using magnetic nanoparticles.

    Science.gov (United States)

    Giouroudi, Ioanna; Keplinger, Franz

    2013-09-09

    In recent years, there has been rapidly growing interest in developing hand held, sensitive and cost-effective on-chip biosensing systems that directly translate the presence of certain bioanalytes (e.g., biomolecules, cells and viruses) into an electronic signal. The impressive and rapid progress in micro- and nanotechnology as well as in biotechnology enables the integration of a variety of analytical functions in a single chip. All necessary sample handling and analysis steps are then performed within the chip. Microfluidic systems for biomedical analysis usually consist of a set of units, which guarantees the manipulation, detection and recognition of bioanalytes in a reliable and flexible manner. Additionally, the use of magnetic fields for performing the aforementioned tasks has been steadily gaining interest. This is because magnetic fields can be well tuned and applied either externally or from a directly integrated solution in the biosensing system. In combination with these applied magnetic fields, magnetic nanoparticles are utilized. Some of the merits of magnetic nanoparticles are the possibility of manipulating them inside microfluidic channels by utilizing high gradient magnetic fields, their detection by integrated magnetic microsensors, and their flexibility due to functionalization by means of surface modification and specific binding. Their multi-functionality is what makes them ideal candidates as the active component in miniaturized on-chip biosensing systems. In this review, focus will be given to the type of biosening systems that use microfluidics in combination with magnetoresistive sensors and detect the presence of bioanalyte tagged with magnetic nanoparticles.

  5. Microfluidic bioreactors for culture of non-adherent cells

    DEFF Research Database (Denmark)

    Shah, Pranjul Jaykumar; Vedarethinam, Indumathi; Kwasny, Dorota

    2011-01-01

    Microfluidic bioreactors (μBR) are becoming increasingly popular for cell culture, sample preparation and analysis in case of routine genetic and clinical diagnostics. We present a novel μBR for non-adherent cells designed to mimic in vivo perfusion of cells based on diffusion of media through...

  6. [Detection of genetic variability in Cercospora kikuchii isolates from a single soybean field].

    Science.gov (United States)

    Lurá, M C; Di Conza, J A; González, A M; Latorre Rapela, M G; Turino, L; Ibáñez, M M; Iacona, V

    2007-01-01

    Detection of genetic variability in Cercospora kikuchii isolates from a single soybean field. Current knowledge about epidemiology and population structure of Cercospora kikuchii is little developed and no studies regarding this subject have been reported in Argentina. The aim of this work was to select primers to study genetic variability in C. kikuchii isolated from the same soybean field using RAPD (Random Amplified Polymorphism DNA). RAPD was applied to the DNA of 5 C. kikuchii, isolated from diseased tissue of the soybean in the same field, another isolate, from a strain collection. Out of seven primers, five of them proved to be useful to study the population of C. kikuchii isolates.

  7. An information-gain approach to detecting three-way epistatic interactions in genetic association studies

    DEFF Research Database (Denmark)

    Hu, Ting; Chen, Yuanzhu; Kiralis, Jeff W;

    2013-01-01

    Background Epistasis has been historically used to describe the phenomenon that the effect of a given gene on a phenotype can be dependent on one or more other genes, and is an essential element for understanding the association between genetic and phenotypic variations. Quantifying epistasis....... In the tuberculosis data, we found a statistically significant pure three-way epistatic interaction effect that was stronger than any lower-order associations. Conclusion Our study provides a methodological basis for detecting and characterizing high-order gene-gene interactions in genetic association studies....

  8. An electrochemiluminescence non-PCR method for the detection of genetically modified organisms

    Science.gov (United States)

    Liu, Jinfeng; Xing, Da; Zhu, Debin

    2006-09-01

    An electrochemiluminescence non-PCR method has been developed for the detection of genetically modified organisms (GMOs) in crops. Genomic DNA of GMOs was digested with two restriction endonucleases (FOK I and BsrD I), and hybridized with three Ru(bpy) 3 2+ (TBR)-labeled and one biotinylated probes. The hybridization products were captured onto streptavidin-coated paramagnetic beads, and detected by measuring the electrochemiluminescence (ECL) signal of the TBR label. Whether the tobaccos contain GM components was discriminated by detecting the ECL signal of CaMV35S promoter. The experiment results show that the detection limit for CaMV35S promoter is 100 fmol, and the GM components can be clearly identified in GM tobaccos. The ECL non-PCR method will provide a new means in GMOs detection due to its safety, simplicity and high efficiency.

  9. Statistical power to detect genetic (covariance of complex traits using SNP data in unrelated samples.

    Directory of Open Access Journals (Sweden)

    Peter M Visscher

    2014-04-01

    Full Text Available We have recently developed analysis methods (GREML to estimate the genetic variance of a complex trait/disease and the genetic correlation between two complex traits/diseases using genome-wide single nucleotide polymorphism (SNP data in unrelated individuals. Here we use analytical derivations and simulations to quantify the sampling variance of the estimate of the proportion of phenotypic variance captured by all SNPs for quantitative traits and case-control studies. We also derive the approximate sampling variance of the estimate of a genetic correlation in a bivariate analysis, when two complex traits are either measured on the same or different individuals. We show that the sampling variance is inversely proportional to the number of pairwise contrasts in the analysis and to the variance in SNP-derived genetic relationships. For bivariate analysis, the sampling variance of the genetic correlation additionally depends on the harmonic mean of the proportion of variance explained by the SNPs for the two traits and the genetic correlation between the traits, and depends on the phenotypic correlation when the traits are measured on the same individuals. We provide an online tool for calculating the power of detecting genetic (covariation using genome-wide SNP data. The new theory and online tool will be helpful to plan experimental designs to estimate the missing heritability that has not yet been fully revealed through genome-wide association studies, and to estimate the genetic overlap between complex traits (diseases in particular when the traits (diseases are not measured on the same samples.

  10. APPLICATION OF GENETIC DEAFNESS GENE CHIP FOR DETECTION OF GENE MUTATION OF DEAFNESS IN PREGNANT WOMEN

    Institute of Scientific and Technical Information of China (English)

    CHANG Liang; ZHONG Su; ZHAO Nan; LIU Ping; ZHAO Yangyu; QIAO Jie

    2014-01-01

    Objective The study is to identify the carrier rate of common deafness mutation in Chinese pregnant women via detecting deafness gene mutations with gene chip. Methods The pregnant women in obstetric clinic without hearing impairment and hearing disorders family history were selected. The informed consent was signed. Peripheral blood was taken to extract genom-ic DNA. Application of genetic deafness gene chip for detecting 9 mutational hot spot of the most common 4 Chinese deafness genes, namely GJB2 (35delG,176del16bp, 235delC, 299delAT), GJB3 (C538T) ,SLC26A4 ( IVS72A>G, A2168G) and mito-chondrial DNA 12S rRNA (A1555G, C1494T) . Further genetic testing were provided to the spouses and newborns of the screened carriers. Results Peripheral blood of 430 pregnant women were detected,detection of deafness gene mutation carri-ers in 24 cases(4.2%), including 13 cases of the GJB2 heterozygous mutation, 3 cases of SLC26A4 heterozygous mutation, 1 cases of GJB3 heterozygous mutation, and 1 case of mitochondrial 12S rRNA mutation. 18 spouses and 17 newborns took fur-ther genetic tests, and 6 newborns inherited the mutation from their mother. Conclusion The common deafness genes muta-tion has a high carrier rate in pregnant women group,235delC and IVS7-2A>G heterozygous mutations are common.

  11. Molecular detection and genetic diversity of Babesia gibsoni in dogs in Bangladesh.

    Science.gov (United States)

    Terao, Masashi; Akter, Shirin; Yasin, Md Golam; Nakao, Ryo; Kato, Hirotomo; Alam, Mohammad Zahangir; Katakura, Ken

    2015-04-01

    Babesia gibsoni is a tick-borne hemoprotozoan parasite of dogs that often causes fever and hemolytic illness. Detection of B. gibsoni has been predominantly reported in Asian countries, including Japan, Korea, Taiwan, Malaysia, Bangladesh and India. The present study shows the first molecular characterization of B. gibsoni detected from dogs in Bangladesh. Blood samples were collected on FTA® Elute cards from 50 stray dogs in Mymensingh District in Bangladesh. DNA eluted from the cards was subjected to nested PCR for the 18S rRNA gene of Babesia species. Approximately 800bp PCR products were detected in 15 of 50 dogs (30%). Based on restriction fragment length polymorphism (RFLP) and direct sequencing of the PCR products, all parasite isolates were identified as B. gibsoni. Furthermore, the BgTRAP (B. gibsoni thrombospondin-related adhesive protein) gene fragments were detected in 13 of 15 18S rRNA gene PCR positive blood samples. Phylogenetic analysis of the BgTRAP gene revealed that B. gibsoni parasites in Bangladesh formed a cluster, which was genetically different from other Asian B. gibsoni isolates. In addition, tandem repeat analysis of the BgTRAP gene clearly showed considerable genetic variation among Bangladeshi isolates. These results suggested that B. gibsoni parasites in a different genetic clade are endemic in dogs in Bangladesh. Further studies are required to elucidate the origin, distribution, vector and pathogenesis of B. gibsoni parasites circulating in dogs in Bangladesh.

  12. Microfluidic Production of Multiple Emulsions

    Directory of Open Access Journals (Sweden)

    Goran T. Vladisavljević

    2017-03-01

    Full Text Available Microfluidic devices are promising tools for the production of monodispersed tuneable complex emulsions. This review highlights the advantages of microfluidics for the fabrication of emulsions and presents an overview of the microfluidic emulsification methods including two-step and single-step methods for the fabrication of high-order multiple emulsions (double, triple, quadruple and quintuple and emulsions with multiple and/or multi-distinct inner cores. The microfluidic methods for the formation of multiple emulsion drops with ultra-thin middle phase, multi-compartment jets, and Janus and ternary drops composed of two or three distinct surface regions are also presented. Different configurations of microfluidic drop makers are covered, such as co-flow, T-junctions and flow focusing (both planar and three-dimensional (3D. Furthermore, surface modifications of microfluidic channels and different modes of droplet generation are summarized. Non-confined microfluidic geometries used for buoyancy-driven drop generation and membrane integrated microfluidics are also discussed. The review includes parallelization and drop splitting strategies for scaling up microfluidic emulsification. The productivity of a single drop maker is typically <1 mL/h; thus, more than 1000 drop makers are needed to achieve commercially relevant droplet throughputs of >1 L/h, which requires combining drop makers into twodimensional (2D and 3D assemblies fed from a single set of inlet ports through a network of distribution and collection channels.

  13. Methods of making microfluidic devices

    KAUST Repository

    Buttner, Ulrich

    2017-06-01

    Microfluidics has advanced in terms of designs and structures, however, fabrication methods are either time consuming or expensive to produce, in terms of the facilities and equipment needed. A fast and economically viable method is provided to allow, for example, research groups to have access to microfluidic fabrication. Unlike most fabrication methods, a method is provided to fabricate a microfluidic device in one step. In an embodiment, a resolution of 50 micrometers was achieved by using maskless high-resolution digital light projection (MDLP). Bonding and channel fabrication of complex or simple structures can be rapidly incorporated to fabricate the microfluidic devices.

  14. A microfluidic dialysis device for complex biological mixture SERS analysis

    KAUST Repository

    Perozziello, Gerardo

    2015-08-01

    In this paper, we present a microfluidic device fabricated with a simple and inexpensive process allowing rapid filtering of peptides from a complex mixture. The polymer microfluidic device can be used for sample preparation in biological applications. The device is fabricated by micromilling and solvent assisted bonding, in which a microdialysis membrane (cut-off of 12-14 kDa) is sandwiched in between an upper and a bottom microfluidic chamber. An external frame connects the microfluidic device to external tubes, microvalves and syringe pumps. Bonding strength and interface sealing are pneumatically tested. Microfluidic protocols are also described by using the presented device to filter a sample composed of specific peptides (MW 1553.73 Da, at a concentration of 1.0 ng/μl) derived from the BRCA1 protein, a tumor-suppressor molecule which plays a pivotal role in the development of breast cancer, and albumin (MW 66.5 kDa, at a concentration of 35 μg/μl), the most represented protein in human plasma. The filtered samples coming out from the microfluidic device were subsequently deposited on a SERS (surface enhanced Raman scattering) substrate for further analysis by Raman spectroscopy. By using this approach, we were able to sort the small peptides from the bigger and highly concentrated protein albumin and to detect them by using a label-free technique at a resolution down to 1.0 ng/μl.

  15. Microfluidic bubble logic.

    Science.gov (United States)

    Prakash, Manu; Gershenfeld, Neil

    2007-02-09

    We demonstrate universal computation in an all-fluidic two-phase microfluidic system. Nonlinearity is introduced into an otherwise linear, reversible, low-Reynolds number flow via bubble-to-bubble hydrodynamic interactions. A bubble traveling in a channel represents a bit, providing us with the capability to simultaneously transport materials and perform logical control operations. We demonstrate bubble logic AND/OR/NOT gates, a toggle flip-flop, a ripple counter, timing restoration, a ring oscillator, and an electro-bubble modulator. These show the nonlinearity, gain, bistability, synchronization, cascadability, feedback, and programmability required for scalable universal computation. With increasing complexity in large-scale microfluidic processors, bubble logic provides an on-chip process control mechanism integrating chemistry and computation.

  16. Microfluidic colloid filtration

    Science.gov (United States)

    Linkhorst, John; Beckmann, Torsten; Go, Dennis; Kuehne, Alexander J. C.; Wessling, Matthias

    2016-03-01

    Filtration of natural and colloidal matter is an essential process in today’s water treatment processes. The colloidal matter is retained with the help of micro- and nanoporous synthetic membranes. Colloids are retained in a “cake layer” – often coined fouling layer. Membrane fouling is the most substantial problem in membrane filtration: colloidal and natural matter build-up leads to an increasing resistance and thus decreasing water transport rate through the membrane. Theoretical models exist to describe macroscopically the hydrodynamic resistance of such transport and rejection phenomena; however, visualization of the various phenomena occurring during colloid retention is extremely demanding. Here we present a microfluidics based methodology to follow filter cake build up as well as transport phenomena occuring inside of the fouling layer. The microfluidic colloidal filtration methodology enables the study of complex colloidal jamming, crystallization and melting processes as well as translocation at the single particle level.

  17. The Microfluidic Jukebox

    Science.gov (United States)

    Tan, Say Hwa; Maes, Florine; Semin, Benoît; Vrignon, Jérémy; Baret, Jean-Christophe

    2014-04-01

    Music is a form of art interweaving people of all walks of life. Through subtle changes in frequencies, a succession of musical notes forms a melody which is capable of mesmerizing the minds of people. With the advances in technology, we are now able to generate music electronically without relying solely on physical instruments. Here, we demonstrate a musical interpretation of droplet-based microfluidics as a form of novel electronic musical instruments. Using the interplay of electric field and hydrodynamics in microfluidic devices, well controlled frequency patterns corresponding to musical tracks are generated in real time. This high-speed modulation of droplet frequency (and therefore of droplet sizes) may also provide solutions that reconciles high-throughput droplet production and the control of individual droplet at production which is needed for many biochemical or material synthesis applications.

  18. Microfluidic redox battery.

    Science.gov (United States)

    Lee, Jin Wook; Goulet, Marc-Antoni; Kjeang, Erik

    2013-07-01

    A miniaturized microfluidic battery is proposed, which is the first membraneless redox battery demonstrated to date. This unique concept capitalizes on dual-pass flow-through porous electrodes combined with stratified, co-laminar flow to generate electrical power on-chip. The fluidic design is symmetric to allow for both charging and discharging operations in forward, reverse, and recirculation modes. The proof-of-concept device fabricated using low-cost materials integrated in a microfluidic chip is shown to produce competitive power levels when operated on a vanadium redox electrolyte. A complete charge/discharge cycle is performed to demonstrate its operation as a rechargeable battery, which is an important step towards providing sustainable power to lab-on-a-chip and microelectronic applications.

  19. Evaluation of terrestrial microcosms for detection, fate, and survival analysis of genetically engineered microorganisms and their recombinant genetic material

    Energy Technology Data Exchange (ETDEWEB)

    Fredrickson, J.K.; Seidler, R.J.

    1989-02-01

    The research included in this document represents the current scientific information available regarding the applicability of terrestrial microcosms and related methodologies for evaluating detection methods and the fate and survival of microorganisms in the environment. The three terrestrial microcosms described in this document were used to evaluate the survival and fate of recombinant bacteria in soils and in association with plant surfaces and insects and their transport through soil with percolating water and root systems, and to test new methods and procedures to improve detection and enumeration of bacteria in soil. Simple (potting soil composed of peat mix and perlite, lacking environmental control and monitoring) and complex microcosms (agricultural soil with partial control and monitoring of environmental conditions) were demonstrated to be useful tools for preliminary assessments of microbial viability in terrestrial ecosystems. These studies evaluated the survival patterns of Enterobacter cloacae (pBR322) in soil and on plant surfaces and the ingestion of this same microorganism by cutworms and survival in the foregut and frass. The Versacore microcosm design was used to monitor the fate and competitiveness of genetically engineered bacteria in soil. Both selective media and gene probes were used successfully to follow the fate of two recombinant Pseudomonas sp. introduced into Versacore microcosms. Intact soil-core microcosms were employed to evaluate the fate and transport of genetically altered Azospirillum sp. and Pseudomonas sp. in soil and the plant rhizosphere. The usefulness of these various microcosms as a tool for risk assessment is underscored by the ease in obtaining soil from a proposed field release site to evaluate subsequent GEM fate and survival.

  20. Detection vs. selection: integration of genetic, epigenetic and environmental cues in fluctuating environments.

    Science.gov (United States)

    McNamara, John M; Dall, Sasha R X; Hammerstein, Peter; Leimar, Olof

    2016-10-01

    There are many inputs during development that influence an organism's fit to current or upcoming environments. These include genetic effects, transgenerational epigenetic influences, environmental cues and developmental noise, which are rarely investigated in the same formal framework. We study an analytically tractable evolutionary model, in which cues are integrated to determine mature phenotypes in fluctuating environments. Environmental cues received during development and by the mother as an adult act as detection-based (individually observed) cues. The mother's phenotype and a quantitative genetic effect act as selection-based cues (they correlate with environmental states after selection). We specify when such cues are complementary and tend to be used together, and when using the most informative cue will predominate. Thus, we extend recent analyses of the evolutionary implications of subsets of these effects by providing a general diagnosis of the conditions under which detection and selection-based influences on development are likely to evolve and coexist.

  1. High-throughput droplet analysis and multiplex DNA detection in the microfluidic platform equipped with a robust sample-introduction technique.

    Science.gov (United States)

    Chen, Jinyang; Ji, Xinghu; He, Zhike

    2015-08-12

    In this work, a simple, flexible and low-cost sample-introduction technique was developed and integrated with droplet platform. The sample-introduction strategy was realized based on connecting the components of positive pressure input device, sample container and microfluidic chip through the tygon tubing with homemade polydimethylsiloxane (PDMS) adaptor, so the sample was delivered into the microchip from the sample container under the driving of positive pressure. This sample-introduction technique is so robust and compatible that could be integrated with T-junction, flow-focus or valve-assisted droplet microchips. By choosing the PDMS adaptor with proper dimension, the microchip could be flexibly equipped with various types of familiar sample containers, makes the sampling more straightforward without trivial sample transfer or loading. And the convenient sample changing was easily achieved by positioning the adaptor from one sample container to another. Benefiting from the proposed technique, the time-dependent concentration gradient was generated and applied for quantum dot (QD)-based fluorescence barcoding within droplet chip. High-throughput droplet screening was preliminarily demonstrated through the investigation of the quenching efficiency of ruthenium complex to the fluorescence of QD. More importantly, multiplex DNA assay was successfully carried out in the integrated system, which shows the practicability and potentials in high-throughput biosensing.

  2. Logic control of microfluidics with smart colloid

    KAUST Repository

    Wang, Limu

    2010-01-01

    We report the successful realization of a microfluidic chip with switching and corresponding inverting functionalities. The chips are identical logic control components incorporating a type of smart colloid, giant electrorheological fluid (GERF), which possesses reversible characteristics via a liquid-solid phase transition under external electric field. Two pairs of electrodes embedded on the sides of two microfluidic channels serve as signal input and output, respectively. One, located in the GERF micro-channel is used to control the flow status of GERF, while another one in the ither micro-fluidic channel is used to detect the signal generated with a passing-by droplet (defined as a signal droplet). Switching of the GERF from the suspended state (off-state) to the flowing state (on-state) or vice versa in the micro-channel is controlled by the appearance of signal droplets whenever they pass through the detection electrode. The output on-off signals can be easily demonstrated, clearly matching with GERF flow status. Our results show that such a logic switch is also a logic IF gate, while its inverter functions as a NOT gate. © The Royal Society of Chemistry 2010.

  3. Droplet based microfluidics.

    Science.gov (United States)

    Seemann, Ralf; Brinkmann, Martin; Pfohl, Thomas; Herminghaus, Stephan

    2012-01-01

    Droplet based microfluidics is a rapidly growing interdisciplinary field of research combining soft matter physics, biochemistry and microsystems engineering. Its applications range from fast analytical systems or the synthesis of advanced materials to protein crystallization and biological assays for living cells. Precise control of droplet volumes and reliable manipulation of individual droplets such as coalescence, mixing of their contents, and sorting in combination with fast analysis tools allow us to perform chemical reactions inside the droplets under defined conditions. In this paper, we will review available drop generation and manipulation techniques. The main focus of this review is not to be comprehensive and explain all techniques in great detail but to identify and shed light on similarities and underlying physical principles. Since geometry and wetting properties of the microfluidic channels are crucial factors for droplet generation, we also briefly describe typical device fabrication methods in droplet based microfluidics. Examples of applications and reaction schemes which rely on the discussed manipulation techniques are also presented, such as the fabrication of special materials and biophysical experiments.

  4. Droplet based microfluidics

    Science.gov (United States)

    Seemann, Ralf; Brinkmann, Martin; Pfohl, Thomas; Herminghaus, Stephan

    2012-01-01

    Droplet based microfluidics is a rapidly growing interdisciplinary field of research combining soft matter physics, biochemistry and microsystems engineering. Its applications range from fast analytical systems or the synthesis of advanced materials to protein crystallization and biological assays for living cells. Precise control of droplet volumes and reliable manipulation of individual droplets such as coalescence, mixing of their contents, and sorting in combination with fast analysis tools allow us to perform chemical reactions inside the droplets under defined conditions. In this paper, we will review available drop generation and manipulation techniques. The main focus of this review is not to be comprehensive and explain all techniques in great detail but to identify and shed light on similarities and underlying physical principles. Since geometry and wetting properties of the microfluidic channels are crucial factors for droplet generation, we also briefly describe typical device fabrication methods in droplet based microfluidics. Examples of applications and reaction schemes which rely on the discussed manipulation techniques are also presented, such as the fabrication of special materials and biophysical experiments.

  5. Dry-Mass Sensing for Microfluidics

    CERN Document Server

    Müller, T; Knowles, T P J

    2014-01-01

    We present an approach for interfacing an electromechanical sensor with a microfluidic device for the accurate quantification of the dry mass of analytes within microchannels. We show that depositing solutes onto the active surface of a quartz crystal microbalance by means of an on-chip microfluidic spray nozzle and subsequent solvent removal provides the basis for the real-time determination of dry solute mass. Moreover, this detection scheme does not suffer from the decrease in the sensor quality factor and the viscous drag present if the measurement is performed in a liquid environment, yet allows solutions to be analysed. We demonstrate the sensitivity and reliability of our approach by controlled deposition of nanogram levels of salt and protein from a micrometer-sized channel.

  6. Cavity optomechanics on a microfluidic resonator

    CERN Document Server

    Kim, Kyu Hyun; Lee, Wonsuk; Liu, Jing; Tomes, Matthew; Fan, Xudong; Carmon, Tal

    2012-01-01

    Light pressure is known to excite or cool vibrations in microresonators for sensing quantum-optomechanical effects and we now show that it can be explored for investigations with liquids. Currently, optical resonances are utilized to detect analytes in liquids. However, optomechanical oscillations have never been excited when devices were immersed in liquid. This is because replacing the surrounding air with water inherently increases the acoustical impedance and the associated acoustical-radiation losses. Here we fabricate a hollow optomechanical bubble resonator with water inside, and use light pressure to excite 8 MHz - 140 MHz vibrations with 1 mW optical-threshold power and >2000 mechanical Q, constituting the first time that any microfluidic system is optomechanically actuated. Bridging between optomechanics and microfluidics will enable recently developed capillaries and on-chip bubbles to vibrate via optical excitation; and allow optomechanics with non-solid material phases including bio-analytes, sup...

  7. Microfluidic Scintillation Detectors for High Energy Physics

    CERN Document Server

    Maoddi, Pietro; Mapelli, Alessandro

    This thesis deals with the development and study of microfluidic scintillation detectors, a technology of recent introduction for the detection of high energy particles. Most of the interest for such devices comes from the use of a liquid scintillator, which entails the possibility of changing the active material in the detector, leading to increased radiation resistance. A first part of the thesis focuses on the work performed in terms of design and modelling studies of novel prototype devices, hinting to new possibilities and applications. In this framework, the simulations performed to validate selected designs and the main technological choices made in view of their fabrication are addressed. The second part of this thesis deals with the microfabrication of several prototype devices. Two different materials were studied for the manufacturing of microfluidic scintillation detectors, namely the SU-8 photosensitive epoxy and monocrystalline silicon. For what concerns the former, an original fabrication appro...

  8. Synthesis and cell-free cloning of DNA libraries using programmable microfluidics.

    Science.gov (United States)

    Ben Yehezkel, Tuval; Rival, Arnaud; Raz, Ofir; Cohen, Rafael; Marx, Zipora; Camara, Miguel; Dubern, Jean-Frédéric; Koch, Birgit; Heeb, Stephan; Krasnogor, Natalio; Delattre, Cyril; Shapiro, Ehud

    2016-02-29

    Microfluidics may revolutionize our ability to write synthetic DNA by addressing several fundamental limitations associated with generating novel genetic constructs. Here we report the first de novo synthesis and cell-free cloning of custom DNA libraries in sub-microliter reaction droplets using programmable digital microfluidics. Specifically, we developed Programmable Order Polymerization (POP), Microfluidic Combinatorial Assembly of DNA (M-CAD) and Microfluidic In-vitro Cloning (MIC) and applied them to de novo synthesis, combinatorial assembly and cell-free cloning of genes, respectively. Proof-of-concept for these methods was demonstrated by programming an autonomous microfluidic system to construct and clone libraries of yeast ribosome binding sites and bacterial Azurine, which were then retrieved in individual droplets and validated. The ability to rapidly and robustly generate designer DNA molecules in an autonomous manner should have wide application in biological research and development.

  9. Novel immunoassay formats for integrated microfluidic circuits: diffusion immunoassays (DIA)

    Science.gov (United States)

    Weigl, Bernhard H.; Hatch, Anson; Kamholz, Andrew E.; Yager, Paul

    2000-03-01

    Novel designs of integrated fluidic microchips allow separations, chemical reactions, and calibration-free analytical measurements to be performed directly in very small quantities of complex samples such as whole blood and contaminated environmental samples. This technology lends itself to applications such as clinical diagnostics, including tumor marker screening, and environmental sensing in remote locations. Lab-on-a-Chip based systems offer many *advantages over traditional analytical devices: They consume extremely low volumes of both samples and reagents. Each chip is inexpensive and small. The sampling-to-result time is extremely short. They perform all analytical functions, including sampling, sample pretreatment, separation, dilution, and mixing steps, chemical reactions, and detection in an integrated microfluidic circuit. Lab-on-a-Chip systems enable the design of small, portable, rugged, low-cost, easy to use, yet extremely versatile and capable diagnostic instruments. In addition, fluids flowing in microchannels exhibit unique characteristics ('microfluidics'), which allow the design of analytical devices and assay formats that would not function on a macroscale. Existing Lab-on-a-chip technologies work very well for highly predictable and homogeneous samples common in genetic testing and drug discovery processes. One of the biggest challenges for current Labs-on-a-chip, however, is to perform analysis in the presence of the complexity and heterogeneity of actual samples such as whole blood or contaminated environmental samples. Micronics has developed a variety of Lab-on-a-Chip assays that can overcome those shortcomings. We will now present various types of novel Lab- on-a-Chip-based immunoassays, including the so-called Diffusion Immunoassays (DIA) that are based on the competitive laminar diffusion of analyte molecules and tracer molecules into a region of the chip containing antibodies that target the analyte molecules. Advantages of this

  10. Microfluidic desalination. Capacitive deionization on chip for microfluidic sample preparation

    NARCIS (Netherlands)

    Roelofs, Susan Helena

    2015-01-01

    The main aim of the work described in this thesis is to implement the desalination technique capacitive deionization (CDI) on a microfluidic chip to improve the reproducibility in the analysis of biological samples for drug development. Secondly, microfluidic CDI allows for the in situ study of ion

  11. Detection and genetic characterization of a novel parvovirus distantly related to human bufavirus in domestic pigs.

    Science.gov (United States)

    Hargitai, Renáta; Pankovics, Péter; Kertész, Attila Mihály; Bíró, Hunor; Boros, Ákos; Phan, Tung Gia; Delwart, Eric; Reuter, Gábor

    2016-04-01

    In this study, a novel parvovirus (strain swine/Zsana3/2013/HUN, KT965075) was detected in domestic pigs and genetically characterized by viral metagenomics and PCR methods. The novel parvovirus was distantly related to the human bufaviruses and was detected in 19 (90.5 %) of the 21 and five (33.3 %) of the 15 faecal samples collected from animals with and without cases of posterior paraplegia of unknown etiology from five affected farms and one control farm in Hungary, respectively. Swine/Zsana3/2013/HUN is highly prevalent in domestic pigs and potentially represents a novel parvovirus species in the subfamily Parvovirinae.

  12. Fast detection of genetic information by an optimized PCR in an interchangeable chip.

    KAUST Repository

    Wu, Jinbo

    2012-02-01

    In this paper, we report the construction of a polymerase chain reaction (PCR) device for fast amplification and detection of DNA. This device consists of an interchangeable PCR chamber, a temperature control component as well as an optical detection system. The DNA amplification happens on an interchangeable chip with the volumes as low as 1.25 μl, while the heating and cooling rate was as fast as 12.7°C/second ensuring that the total time needed of only 25 min to complete the 35 cycle PCR amplification. An optimized PCR with two-temperature approach for denaturing and annealing (Td and Ta) of DNA was also formulated with the PCR chip, with which the amplification of male-specific sex determining region Y (SRY) gene marker by utilizing raw saliva was successfully achieved and the genetic identification was in-situ detected right after PCR by the optical detection system.

  13. Apparatus, System and Method for Fast Detection of Genetic Information by PCR in an Interchangeable Chip

    KAUST Repository

    Wen, Weijia

    2011-03-03

    A polymerase chain reaction (PCR) device for fast amplification and detection of DNA includes an interchangeable PCR chamber, a temperature control component, and an optical detection system. The DNA amplification is performed on an interchangeable chip with volumes as small as 1.25 µl, while the heating and cooling rate may be as fast as 12.7 °C/second ensuring that the total time needed of only 25 minutes to complete the 35 cycle PCR amplification. The PCR may be performed according to a two-temperature approach for denaturing and annealing (Td and Ta) of DNA with the PCR chip, with which the amplification of male-specific SRY gene marker by utilizing raw saliva may be achieved. The genetic identification may be in-situ detected after PCR by the optical detection system.

  14. Automated detection of lung nodules in CT images using shape-based genetic algorithm.

    Science.gov (United States)

    Dehmeshki, Jamshid; Ye, Xujiong; Lin, Xinyu; Valdivieso, Manlio; Amin, Hamdan

    2007-09-01

    A shape-based genetic algorithm template-matching (GATM) method is proposed for the detection of nodules with spherical elements. A spherical-oriented convolution-based filtering scheme is used as a pre-processing step for enhancement. To define the fitness function for GATM, a 3D geometric shape feature is calculated at each voxel and then combined into a global nodule intensity distribution. Lung nodule phantom images are used as reference images for template matching. The proposed method has been validated on a clinical dataset of 70 thoracic CT scans (involving 16,800 CT slices) that contains 178 nodules as a gold standard. A total of 160 nodules were correctly detected by the proposed method and resulted in a detection rate of about 90%, with the number of false positives at approximately 14.6/scan (0.06/slice). The high-detection performance of the method suggested promising potential for clinical applications.

  15. Vibration-Based Damage Detection in Beams by Cooperative Coevolutionary Genetic Algorithm

    Directory of Open Access Journals (Sweden)

    Kittipong Boonlong

    2014-03-01

    Full Text Available Vibration-based damage detection, a nondestructive method, is based on the fact that vibration characteristics such as natural frequencies and mode shapes of structures are changed when the damage happens. This paper presents cooperative coevolutionary genetic algorithm (CCGA, which is capable for an optimization problem with a large number of decision variables, as the optimizer for the vibration-based damage detection in beams. In the CCGA, a minimized objective function is a numerical indicator of differences between vibration characteristics of the actual damage and those of the anticipated damage. The damage detection in a uniform cross-section cantilever beam, a uniform strength cantilever beam, and a uniform cross-section simply supported beam is used as the test problems. Random noise in the vibration characteristics is also considered in the damage detection. In the simulation analysis, the CCGA provides the superior solutions to those that use standard genetic algorithms presented in previous works, although it uses less numbers of the generated solutions in solution search. The simulation results reveal that the CCGA can efficiently identify the occurred damage in beams for all test problems including the damage detection in a beam with a large number of divided elements such as 300 elements.

  16. Role of genetic detection in peritoneal washes with gastric carcinoma: The past, present and future

    Institute of Scientific and Technical Information of China (English)

    Hyun-Dong Chae

    2016-01-01

    The most frequent cause of treatment failure following surgery for gastric cancer is peritoneal dissemination, mainly caused by the seeding of free cancer cells from the primary gastric cancer, which is the most common type of spread. Unfortunately, there is no standard modality of intraperitoneal free cancer cells detection to predict peritoneal metastasis until now. We reviewed English literature in Pub Med was done using the Me SH terms for gastric cancer, peritoneal wash, and reverse transcriptase polymerase chain reaction. All the articles were reviewed and core information was tabulated for reference. After a comprehensive review of all articles, the data was evaluated by clinical implication and predictive value of each marker for peritoneal recurrence. There are still many limitations to overcome before the genetic diagnosis for free cancer cells detection can be considered as routine assay. To make it a reliable diagnostic tool for detecting free cancer cells, the process and method of genetic detection with peritoneal washes should be standardized, and the development of simple diagnostic devices and easily available kits are necessary. Herein, we reviewed the past, present and future perspectives of the peritoneal lavage for the detection of intraperitoneal free cancer cells in patients with gastric cancer.

  17. Model studies on the detectability of genetically modified feeds in milk.

    Science.gov (United States)

    Poms, R E; Hochsteiner, W; Luger, K; Glössl, J; Foissy, H

    2003-02-01

    Detecting the use of genetically modified feeds in milk has become important, because the voluntary labeling of milk and dairy products as "GMO free" or as "organically grown" prohibits the employment of genetically modified organisms (GMOs). The aim of this work was to investigate whether a DNA transfer from foodstuffs like soya and maize was analytically detectable in cow's milk after digestion and transportation via the bloodstream of dairy cows and, thus, whether milk could report for the employment of transgene feeds. Blood, milk, urine, and feces of dairy cows were examined, and foreign DNA was detected by polymerase chain reaction by specifically amplifying a 226-bp fragment of the maize invertase gene and a 118-bp fragment of the soya lectin gene. An intravenous application of purified plant DNA showed a fast elimination of marker DNA in blood or its reduction below the detection limit. With feeding experiments, it could be demonstrated that a specific DNA transfer from feeds into milk was not detectable. Therefore, foreign DNA in milk cannot serve as an indicator for the employment of transgene feeds unless milk is directly contaminated with feed components or airborne feed particles.

  18. Development and evaluation of a real-time fluorogenic loop-mediated isothermal amplification assay integrated on a microfluidic disc chip (on-chip LAMP) for rapid and simultaneous detection of ten pathogenic bacteria in aquatic animals.

    Science.gov (United States)

    Zhou, Qian-Jin; Wang, Lei; Chen, Jiong; Wang, Rui-Na; Shi, Yu-Hong; Li, Chang-Hong; Zhang, De-Min; Yan, Xiao-Jun; Zhang, Yan-Jun

    2014-09-01

    Rapid, low-cost, and user-friendly strategies are urgently needed for early disease diagnosis and timely treatment, particularly for on-site screening of pathogens in aquaculture. In this study, we successfully developed a real-time fluorogenic loop-mediated isothermal amplification assay integrated on a microfluidic disc chip (on-chip LAMP), which was capable of simultaneously detecting 10 pathogenic bacteria in aquatic animals, i.e., Nocardia seriolae, Pseudomonas putida, Streptococcus iniae, Vibrio alginolyticus, Vibrio anguillarum, Vibrio fluvialis, Vibrio harveyi, Vibrio parahaemolyticus, Vibrio rotiferianus, and Vibrio vulnificus. The assay provided a nearly-automated approach, with only a single pipetting step per chip for sample dispensing. This technique could achieve limits of detection (LOD) ranging from 0.40 to 6.42pg per 1.414μL reaction in less than 30 min. The robust reproducibility was demonstrated by a little variation among duplications for each bacterium with the coefficient of variation (CV) for time to positive (Tp) value less than 0.10. The clinical sensitivity and specificity of this on-chip LAMP assay in detecting field samples were 96.2% and 93.8% by comparison with conventional microbiological methods. Compared with other well-known techniques, on-chip LAMP assay provides low sample and reagent consumption, ease-of-use, accelerated analysis, multiple bacteria and on-site detection, and high reproducibility, indicating that such a technique would be applicable for on-site detection and routine monitoring of multiple pathogens in aquaculture.

  19. Automatic Mexico Gulf Oil Spill Detection from Radarsat-2 SAR Satellite Data Using Genetic Algorithm

    Science.gov (United States)

    Marghany, Maged

    2016-10-01

    In this work, a genetic algorithm is exploited for automatic detection of oil spills of small and large size. The route is achieved using arrays of RADARSAT-2 SAR ScanSAR Narrow single beam data obtained in the Gulf of Mexico. The study shows that genetic algorithm has automatically segmented the dark spot patches related to small and large oil spill pixels. This conclusion is confirmed by the receiveroperating characteristic (ROC) curve and ground data which have been documented. The ROC curve indicates that the existence of oil slick footprints can be identified with the area under the curve between the ROC curve and the no-discrimination line of 90%, which is greater than that of other surrounding environmental features. The small oil spill sizes represented 30% of the discriminated oil spill pixels in ROC curve. In conclusion, the genetic algorithm can be used as a tool for the automatic detection of oil spills of either small or large size and the ScanSAR Narrow single beam mode serves as an excellent sensor for oil spill patterns detection and surveying in the Gulf of Mexico.

  20. Molecular Detection of Bladder Cancer by Fluorescence Microsatellite Analysis and an Automated Genetic Analyzing System

    Directory of Open Access Journals (Sweden)

    Sarel Halachmi

    2007-01-01

    Full Text Available To investigate the ability of an automated fluorescent analyzing system to detect microsatellite alterations, in patients with bladder cancer. We investigated 11 with pathology proven bladder Transitional Cell Carcinoma (TCC for microsatellite alterations in blood, urine, and tumor biopsies. DNA was prepared by standard methods from blood, urine and resected tumor specimens, and was used for microsatellite analysis. After the primers were fluorescent labeled, amplification of the DNA was performed with PCR. The PCR products were placed into the automated genetic analyser (ABI Prism 310, Perkin Elmer, USA and were subjected to fluorescent scanning with argon ion laser beams. The fluorescent signal intensity measured by the genetic analyzer measured the product size in terms of base pairs. We found loss of heterozygocity (LOH or microsatellite alterations (a loss or gain of nucleotides, which alter the original normal locus size in all the patients by using fluorescent microsatellite analysis and an automated analyzing system. In each case the genetic changes found in urine samples were identical to those found in the resected tumor sample. The studies demonstrated the ability to detect bladder tumor non-invasively by fluorescent microsatellite analysis of urine samples. Our study supports the worldwide trend for the search of non-invasive methods to detect bladder cancer. We have overcome major obstacles that prevented the clinical use of an experimental system. With our new tested system microsatellite analysis can be done cheaper, faster, easier and with higher scientific accuracy.