WorldWideScience

Sample records for based microfluidic devices

  1. Streamline-based microfluidic device

    Science.gov (United States)

    Tai, Yu-Chong (Inventor); Zheng, Siyang (Inventor); Kasdan, Harvey (Inventor)

    2013-01-01

    The present invention provides a streamline-based device and a method for using the device for continuous separation of particles including cells in biological fluids. The device includes a main microchannel and an array of side microchannels disposed on a substrate. The main microchannel has a plurality of stagnation points with a predetermined geometric design, for example, each of the stagnation points has a predetermined distance from the upstream edge of each of the side microchannels. The particles are separated and collected in the side microchannels.

  2. A microfluidic device based on an evaporation-driven micropump

    NARCIS (Netherlands)

    Nie, C.; Frijns, A.J.H.; Mandamparambil, R.; Toonder, J.M.J. den

    2015-01-01

    In this paper we introduce a microfluidic device ultimately to be applied as a wearable sweat sensor. We show proof-of-principle of the microfluidic functions of the device, namely fluid collection and continuous fluid flow pumping. A filter-paper based layer, that eventually will form the interface

  3. Electrochemical sensing in paper-based microfluidic devices.

    Science.gov (United States)

    Nie, Zhihong; Nijhuis, Christian A; Gong, Jinlong; Chen, Xin; Kumachev, Alexander; Martinez, Andres W; Narovlyansky, Max; Whitesides, George M

    2010-02-21

    This paper describes the fabrication and the performance of microfluidic paper-based electrochemical sensing devices (we call the microfluidic paper-based electrochemical devices, microPEDs). The microPEDs comprise paper-based microfluidic channels patterned by photolithography or wax printing, and electrodes screen-printed from conducting inks (e.g., carbon or Ag/AgCl). We demonstrated that the microPEDs are capable of quantifying the concentrations of various analytes (e.g., heavy-metal ions and glucose) in aqueous solutions. This low-cost analytical device should be useful for applications in public health, environmental monitoring, and the developing world. PMID:20126688

  4. Electrochemical Sensing in Paper-Based Microfluidic Devices

    OpenAIRE

    Nie, Zhihong; Nijhuis, Christian A.; Gong, Jinlong; Chen, Xin; Kumachev, Alexander; Martinez, Andres W.; Narovlyansky, Max; Whitesides, George McClelland

    2010-01-01

    This paper describes the fabrication and the performance of microfluidic paper-based electrochemical sensing devices (we call the microfluidic paper-based electrochemical devices, μPEDs). The μPEDs comprise paper-based microfluidic channels patterned by photolithography or wax printing, and electrodes screen-printed from conducting inks (e.g., carbon or Ag/AgCl). We demonstrated that the μPEDs are capable of quantifying the concentrations of various analytes (e.g., heavy-metal ions and glucos...

  5. Microfluidic Device

    Science.gov (United States)

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

    2016-01-01

    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.

  6. Measurement of the hematocrit using paper-based microfluidic devices.

    Science.gov (United States)

    Berry, Samuel B; Fernandes, Syrena C; Rajaratnam, Anjali; DeChiara, Nicholas S; Mace, Charles R

    2016-10-01

    The quantification of blood cells provides critical information about a patient's health status. Sophisticated analytical equipment, such as hematology analyzers, have been developed to perform these measurements, but limited-resource settings often lack the infrastructure required to purchase, operate, and maintain instrumentation. To address these practical challenges, paper-based microfluidic devices have emerged as a platform to develop diagnostic assays specifically for use at the point-of-care. To date, paper-based microfluidic devices have been used broadly in diagnostic assays that apply immunoassay, clinical chemistry, and electrochemistry techniques. The analysis of cells, however, has been largely overlooked. In this communication, we demonstrate a paper-based microfluidic device that enables the controlled transport of red blood cells (RBCs) and the measurement of the hematocrit-the ratio of RBC packed cell volume to total volume of whole blood. The properties of paper, device treatment, and device geometry affect the overall extent and reproducibility of transport of RBCs. Ultimately, we developed an inexpensive (US$0.03 per device) thermometer-styled device where the distance traveled by RBCs is proportional to the hematocrit. These results provide a foundation for the design of paper-based microfluidic devices that enable the separation and detection of cells in limited-resource settings. PMID:27604182

  7. Paper-based inkjet-printed microfluidic analytical devices.

    Science.gov (United States)

    Yamada, Kentaro; Henares, Terence G; Suzuki, Koji; Citterio, Daniel

    2015-04-27

    Rapid, precise, and reproducible deposition of a broad variety of functional materials, including analytical assay reagents and biomolecules, has made inkjet printing an effective tool for the fabrication of microanalytical devices. A ubiquitous office device as simple as a standard desktop printer with its multiple ink cartridges can be used for this purpose. This Review discusses the combination of inkjet printing technology with paper as a printing substrate for the fabrication of microfluidic paper-based analytical devices (μPADs), which have developed into a fast-growing new field in analytical chemistry. After introducing the fundamentals of μPADs and inkjet printing, it touches on topics such as the microfluidic patterning of paper, tailored arrangement of materials, and functionalities achievable exclusively by the inkjet deposition of analytical assay components, before concluding with an outlook on future perspectives.

  8. Electrochemiluminescence detection in microfluidic cloth-based analytical devices.

    Science.gov (United States)

    Guan, Wenrong; Liu, Min; Zhang, Chunsun

    2016-01-15

    This work describes the first approach at combining microfluidic cloth-based analytical devices (μCADs) with electrochemiluminescence (ECL) detection. Wax screen-printing is employed to make cloth-based microfluidic chambers which are patterned with carbon screen-printed electrodes (SPEs) to create truly disposable, simple, inexpensive sensors which can be read with a low-cost, portable charge coupled device (CCD) imaging sensing system. And, the two most commonly used ECL systems of tris(2,2'-bipyridyl)ruthenium(II)/tri-n-propylamine (Ru(bpy)3(2+)/TPA) and 3-aminophthalhydrazide/hydrogen peroxide (luminol/H2O2) are applied to demonstrate the quantitative ability of the ECL μCADs. In this study, the proposed devices have successfully fulfilled the determination of TPA with a linear range from 2.5 to 2500μM with a detection limit of 1.265μM. In addition, the detection of H2O2 can be performed in the linear range of 0.05-2.0mM, with a detection limit of 0.027mM. It has been shown that the ECL emission on the wax-patterned cloth device has an acceptable sensitivity, stability and reproducibility. Finally, the applicability of cloth-based ECL is demonstrated for determination of glucose in phosphate buffer solution (PBS) and artificial urine (AU) samples, with the detection limits of 0.032mM and 0.038mM, respectively. It can be foreseen, therefore, that μCADs with ECL detection could provide a new sensing platform for point-of-care testing, public health, food safety detection and environmental monitoring in remote regions, developing or developed countries. PMID:26319168

  9. Fabrication of polyimide based microfluidic channels for biosensor devices

    DEFF Research Database (Denmark)

    Zulfiqar, Azeem; Pfreundt, Andrea; Svendsen, Winnie Edith;

    2015-01-01

    microfluidics is inevitable. This paper demonstrates a novel technique of fabricating microfluidic devices using polyimide (PI) which fulfills the aforementioned properties criteria. A fabrication process to pattern microfluidic channels, using partially cured PI, has been developed by using a dry etching...... in uniformity of PI is also compared to the most commonly used SU8 polymer, which is a near UV sensitive epoxy resin. The potential applications of PI processing are POC and biosensor devices integrated with microelectronics.......The ever-increasing complexity of the fabrication process of Point-of-care (POC) devices, due to high demand of functional versatility, compact size and ease-of-use, emphasizes the need of multifunctional materials that can be used to simplify this process. Polymers, currently in use...

  10. Fabrication of polyimide based microfluidic channels for biosensor devices

    Science.gov (United States)

    Zulfiqar, Azeem; Pfreundt, Andrea; Svendsen, Winnie Edith; Dimaki, Maria

    2015-03-01

    The ever-increasing complexity of the fabrication process of Point-of-care (POC) devices, due to high demand of functional versatility, compact size and ease-of-use, emphasizes the need of multifunctional materials that can be used to simplify this process. Polymers, currently in use for the fabrication of the often needed microfluidic channels, have limitations in terms of their physicochemical properties. Therefore, the use of a multipurpose biocompatible material with better resistance to the chemical, thermal and electrical environment, along with capability of forming closed channel microfluidics is inevitable. This paper demonstrates a novel technique of fabricating microfluidic devices using polyimide (PI) which fulfills the aforementioned properties criteria. A fabrication process to pattern microfluidic channels, using partially cured PI, has been developed by using a dry etching method. The etching parameters are optimized and compared to those used for fully cured PI. Moreover, the formation of closed microfluidic channel on wafer level by bonding two partially cured PI layers or a partially cured PI to glass with high bond strength has been demonstrated. The reproducibility in uniformity of PI is also compared to the most commonly used SU8 polymer, which is a near UV sensitive epoxy resin. The potential applications of PI processing are POC and biosensor devices integrated with microelectronics.

  11. 3D Printed Paper-Based Microfluidic Analytical Devices

    Directory of Open Access Journals (Sweden)

    Yong He

    2016-06-01

    Full Text Available As a pump-free and lightweight analytical tool, paper-based microfluidic analytical devices (μPADs attract more and more interest. If the flow speed of μPAD can be programmed, the analytical sequences could be designed and they will be more popular. This reports presents a novel μPAD, driven by the capillary force of cellulose powder, printed by a desktop three-dimensional (3D printer, which has some promising features, such as easy fabrication and programmable flow speed. First, a suitable size-scale substrate with open microchannels on its surface is printed. Next, the surface of the substrate is covered with a thin layer of polydimethylsiloxane (PDMS to seal the micro gap caused by 3D printing. Then, the microchannels are filled with a mixture of cellulose powder and deionized water in an appropriate proportion. After drying in an oven at 60 °C for 30 min, it is ready for use. As the different channel depths can be easily printed, which can be used to achieve the programmable capillary flow speed of cellulose powder in the microchannels. A series of microfluidic analytical experiments, including quantitative analysis of nitrite ion and fabrication of T-sensor were used to demonstrate its capability. As the desktop 3D printer (D3DP is very cheap and accessible, this device can be rapidly printed at the test field with a low cost and has a promising potential in the point-of-care (POC system or as a lightweight platform for analytical chemistry.

  12. Low-cost rapid prototyping of flexible plastic paper based microfluidic devices

    KAUST Repository

    Fan, Yiqiang

    2013-04-01

    This research presents a novel rapid prototyping method for paper-based flexible microfluidic devices. The microchannels were fabricated using laser ablation on a piece of plastic paper (permanent paper), the dimensions of the microchannels was carefully studied for various laser powers and scanning speeds. After laser ablation of the microchannels on the plastic paper, a transparent poly (methyl methacrylate)(PMMA) film was thermally bonded to the plastic paper to enclose the channels. After connection of tubing, the device was ready to use. An example microfluidic device (droplet generator) was also fabricated using this technique. Due to the flexibility of the fabricated device, this technique can be used to fabricate 3D microfluidic devices. The fabrication process was simple and rapid without any requirement of cleanroom facilities. © 2013 IEEE.

  13. Multilayer soft lithography of perfluoropolyether based elastomer for microfluidic device fabrication.

    Science.gov (United States)

    Devaraju, Naga Sai Gopi Krishna; Unger, Marc Alexander

    2011-06-01

    The compatibility of microfluidic devices with solvents and other chemicals is extremely important for many applications such as organic synthesis in microreactors and drug screening. We report the successful fabrication of microfluidic devices from a novel perfluoropolyether based polymer utilizing the Multilayer Soft Lithography™ (MSL) technique with simple, straightforward processing. The perfluorinated polymer SIFEL X-71 8115 is a highly chemically resistant elastomeric material. We demonstrate fabrication of a microfluidic device using an off-ratio bonding technique to bond multiple SIFEL layers, each patterned lithographically. The mechanical properties of the SIFEL MSL valves (including actuation pressures) are similar to PDMS MSL valves of the same geometry. Chemical compatibility tests highlight SIFEL's remarkable resistance to organic solvents, acids and alkalis. PMID:21503367

  14. Fabrication of a Paper-Based Microfluidic Device to Readily Determine Nitrite Ion Concentration by Simple Colorimetric Assay

    Science.gov (United States)

    Wang, Bo; Lin, Zhiqiang; Wang, Min

    2015-01-01

    Paper-based microfluidic devices (µPAD) are a burgeoning platform of microfluidic analysis technology. The method described herein is for use in undergraduate and high school chemistry laboratories. A simple and convenient µPAD was fabricated by easy patterning of filter paper using a permanent marker pen. The usefulness of the device was…

  15. Novel developments in mobile sensing based on the integration of microfluidic devices and smartphones.

    Science.gov (United States)

    Yang, Ke; Peretz-Soroka, Hagit; Liu, Yong; Lin, Francis

    2016-03-21

    Portable electronic devices and wireless communication systems enable a broad range of applications such as environmental and food safety monitoring, personalized medicine and healthcare management. Particularly, hybrid smartphone and microfluidic devices provide an integrated solution for the new generation of mobile sensing applications. Such mobile sensing based on microfluidic devices (broadly defined) and smartphones (MS(2)) offers a mobile laboratory for performing a wide range of bio-chemical detection and analysis functions such as water and food quality analysis, routine health tests and disease diagnosis. MS(2) offers significant advantages over traditional platforms in terms of test speed and control, low cost, mobility, ease-of-operation and data management. These improvements put MS(2) in a promising position in the fields of interdisciplinary basic and applied research. In particular, MS(2) enables applications to remote in-field testing, homecare, and healthcare in low-resource areas. The marriage of smartphones and microfluidic devices offers a powerful on-chip operating platform to enable various bio-chemical tests, remote sensing, data analysis and management in a mobile fashion. The implications of such integration are beyond telecommunication and microfluidic-related research and technology development. In this review, we will first provide the general background of microfluidic-based sensing, smartphone-based sensing, and their integration. Then, we will focus on several key application areas of MS(2) by systematically reviewing the important literature in each area. We will conclude by discussing our perspectives on the opportunities, issues and future directions of this emerging novel field. PMID:26899264

  16. Microfluidic Cell Culture Device

    Science.gov (United States)

    Takayama, Shuichi (Inventor); Cabrera, Lourdes Marcella (Inventor); Heo, Yun Seok (Inventor); Smith, Gary Daniel (Inventor)

    2014-01-01

    Microfluidic devices for cell culturing and methods for using the same are disclosed. One device includes a substrate and membrane. The substrate includes a reservoir in fluid communication with a passage. A bio-compatible fluid may be added to the reservoir and passage. The reservoir is configured to receive and retain at least a portion of a cell mass. The membrane acts as a barrier to evaporation of the bio-compatible fluid from the passage. A cover fluid may be added to cover the bio-compatible fluid to prevent evaporation of the bio-compatible fluid.

  17. Osteocyte culture in microfluidic devices.

    Science.gov (United States)

    Wei, Chao; Fan, Beiyuan; Chen, Deyong; Liu, Chao; Wei, Yuanchen; Huo, Bo; You, Lidan; Wang, Junbo; Chen, Jian

    2015-01-01

    This paper presents a microfluidic device (poly-dimethylsiloxane micro channels bonded with glass slides) enabling culture of MLO-Y4 osteocyte like cells. In this study, on-chip collagen coating, cell seeding and culture, as well as staining were demonstrated in a tubing-free manner where gravity was used as the driving force for liquid transportation. MLO-Y4 cells were cultured in microfluidic channels with and without collagen coating where cellular images in a time sequence were taken and analyzed, confirming the positive effect of collagen coating on phenotype maintaining of MLO-Y4 cells. The proliferating cell nuclear antigen based proliferation assay was used to study cellular proliferation, revealing a higher proliferation rate of MLO-Y4 cells seeded in microfluidic channels without collagen coating compared to the substrates coated with collagen. Furthermore, the effects of channel dimensions (variations in width and height) on the viability of MLO-Y4 cells were explored based on the Calcein-AM and propidium iodide based live/dead assay and the Hoechst 33258 based apoptosis assay, locating the correlation between the decrease in channel width or height and the decrease in cell viability. As a platform technology, this microfluidic device may function as a new cell culture model enabling studies of osteocytes. PMID:25713691

  18. Two-ply channels for faster wicking in paper-based microfluidic devices.

    Science.gov (United States)

    Camplisson, Conor K; Schilling, Kevin M; Pedrotti, William L; Stone, Howard A; Martinez, Andres W

    2015-12-01

    This article describes the development of porous two-ply channels for paper-based microfluidic devices that wick fluids significantly faster than conventional, porous, single-ply channels. The two-ply channels were made by stacking two single-ply channels on top of each other and were fabricated entirely out of paper, wax and toner using two commercially available printers, a convection oven and a thermal laminator. The wicking in paper-based channels was studied and modeled using a modified Lucas-Washburn equation to account for the effect of evaporation, and a paper-based titration device incorporating two-ply channels was demonstrated.

  19. Laser Ablation of Polymer Microfluidic Devices

    Science.gov (United States)

    Killeen, Kevin

    2004-03-01

    Microfluidic technology is ideal for processing precious samples of limited volumes. Some of the most important classes of biological samples are both high in sample complexity and low in concentration. Combining the elements of sample pre-concentration, chemical separation and high sensitivity detection with chemical identification is essential for realizing a functional microfluidic based analysis system. Direct write UV laser ablation has been used to rapidly fabricate microfluidic devices capable of high performance liquid chromatography (HPLC)-MS. These chip-LC/MS devices use bio-compatible, solvent resistant and flexible polymer materials such as polyimide. A novel microfluidic to rotary valve interface enables, leak free, high pressure fluid switching between multiple ports of the microfluidic chip-LC/MS device. Electrospray tips with outer dimension of 50 um and inner of 15 um are formed by ablating the polymer material concentrically around a multilayer laminated channel structure. Biological samples of digested proteins were used to evaluate the performance of these microfluidic devices. Liquid chromatography separation and similar sample pretreatments have been performed using polymeric microfluidic devices with on-chip separation channels. Mass spectrometry was performed using an Agilent Technologies 1100 series ion trap mass spectrometer. Low fmol amounts of protein samples were positively and routinely identified by searching the MS/MS spectral data against protein databases. The sensitivity and separation performance of the chip-LC devices has been found to be comparable to state of the art nano-electrospray systems.

  20. Integration of Multiple Components in Polystyrene-based Microfluidic Devices Part 1: Fabrication and Characterization

    Science.gov (United States)

    Johnson, Alicia S.; Anderson, Kari B.; Halpin, Stephen T.; Kirkpatrick, Douglas C.; Spence, Dana M.; Martin, R. Scott

    2012-01-01

    In Part I of a two-part series, we describe a simple, and inexpensive approach to fabricate polystyrene devices that is based upon melting polystyrene (from either a Petri dish or powder form) against PDMS molds or around electrode materials. The ability to incorporate microchannels in polystyrene and integrate the resulting device with standard laboratory equipment such as an optical plate reader for analyte readout and micropipettors for fluid propulsion is first described. A simple approach for sample and reagent delivery to the device channels using a standard, multi-channel micropipette and a PDMS-based injection block is detailed. Integration of the microfluidic device with these off-chip functions (sample delivery and readout) enables high throughput screens and analyses. An approach to fabricate polystyrene-based devices with embedded electrodes is also demonstrated, thereby enabling the integration of microchip electrophoresis with electrochemical detection through the use of a palladium electrode (for a decoupler) and carbon-fiber bundle (for detection). The device was sealed against a PDMS-based microchannel and used for the electrophoretic separation and amperometric detection of dopamine, epinephrine, catechol, and 3,4-dihydroxyphenylacetic acid. Finally, these devices were compared against PDMS-based microchips in terms of their optical transparency and absorption of an anti-platelet drug, clopidogrel. Part I of this series lays the foundation for Part II, where these devices were utilized for various on-chip cellular analysis. PMID:23120747

  1. Microfluidic Devices for Blood Fractionation

    Directory of Open Access Journals (Sweden)

    Chwee Teck Lim

    2011-07-01

    Full Text Available Blood, a complex biological fluid, comprises 45% cellular components suspended in protein rich plasma. These different hematologic components perform distinct functions in vivo and thus the ability to efficiently fractionate blood into its individual components has innumerable applications in both clinical diagnosis and biological research. Yet, processing blood is not trivial. In the past decade, a flurry of new microfluidic based technologies has emerged to address this compelling problem. Microfluidics is an attractive solution for this application leveraging its numerous advantages to process clinical blood samples. This paper reviews the various microfluidic approaches realized to successfully fractionate one or more blood components. Techniques to separate plasma from hematologic cellular components as well as isolating blood cells of interest including certain rare cells are discussed. Comparisons based on common separation metrics including efficiency (sensitivity, purity (selectivity, and throughput will be presented. Finally, we will provide insights into the challenges associated with blood-based separation systems towards realizing true point-of-care (POC devices and provide future perspectives.

  2. Determination of Nitrite in Saliva using Microfluidic Paper-Based Analytical Devices

    OpenAIRE

    Bhakta, Samir A.; Borba, Rubiane; Taba, Mario; Garcia, Carlos D.; Carrilho, Emanuel

    2013-01-01

    Point-of-care platforms can provide fast responses, decrease the overall cost of the treatment, allow for in-home determinations with or without a trained specialist, and improve the success of the treatment. This is especially true for microfluidic paper-based analytical devices (μPAD), which can enable the development of highly efficient and versatile analytical tools with applications in a variety of biomedical fields. The objective of this work was the development of μPADs to identify and...

  3. Biologically Inspired Electronic, Photovoltaic and Microfluidic Devices Based on Aqueous Soft Matter

    Science.gov (United States)

    Koo, Hyung Jun

    Hydrogels are a water-based soft material where three dimensional networks of hydrophilic polymer retain large amounts of water. We developed hydrogel based devices with new functionalities inspired by materials, structures and processes in nature. The advantages, such as softness, biocompatibility and high ionic conductivity, could enable hydrogels to be novel materials for biomimetic devices operated by ionic current. Moreover, microfluidic patterns are easily embedded in moldable hydrogels and allow for unique convective/diffusive transport mechanism in porous gel to be used for uniform delivery of reagent solution. We first developed and characterized a device with unidirectional ionic current flow across a SiO2/Gel junction, which showed highly efficient rectification of the ionic current by non-linear conductivity of SiO2 films. Addition of polyelectrolytes and salt to the gel layer significantly improved the performance of the new diode device because of the enhanced gel conductance. A soft matter based diode composed of hydrogel and liquid metal (eutectic gallium indium, EGaIn) was also presented. The ability to control the thickness, and thus resistivity, of an insulating oxide skin on the metal enables the current rectification. The effect of ionic conductivity and pH on the formation of the insulating oxide was investigated in a simple model system with liquid metal/electrolyte solution or hydrogel/Pt interfaces. Finally, we present a diode composed entirely of soft materials by replacing the platinum electrode with a second liquid metal electrode. A new type of hydrogel-based photovoltaic systems (HGPVs) was constructed. Two photosensitive ionized molecules embedded in aqueous gel served as photoactive species. The HGPVs showed performance comparable with or higher than those of some other biomimetic or ionic photovoltaic systems reported recently. We suggest a provisional mechanism of the device operation, based on a synergetic effect of the two dye

  4. Integration of Multiple Components in Polystyrene-based Microfluidic Devices Part 2: Cellular Analysis

    Science.gov (United States)

    Anderson, Kari B.; Halpin, Stephen T.; Johnson, Alicia S.; Martin, R. Scott; Spence, Dana M.

    2012-01-01

    In Part II of this series describing the use of polystyrene (PS) devices for microfluidic-based cellular assays, various cellular types and detection strategies are employed to determine three fundamental assays often associated with cells. Specifically, using either integrated electrochemical sensing or optical measurements with a standard multi-well plate reader, cellular uptake, production, or release of important cellular analytes are determined on a PS-based device. One experiment involved the fluorescence measurement of nitric oxide (NO) produced within an endothelial cell line following stimulation with ATP. The result was a four-fold increase in NO production (as compared to a control), with this receptor-based mechanism of NO production verifying the maintenance of cell receptors following immobilization onto the PS substrate. The ability to monitor cellular uptake was also demonstrated by optical determination of Ca2+ into endothelial cells following stimulation with the Ca2+ ionophore A20317. The result was a significant increase (42%) in the calcium uptake in the presence of the ionophore, as compared to a control (17%) (p < 0.05). Finally, the release of catecholamines from a dopaminergic cell line (PC 12 cells) was electrochemically monitored, with the electrodes being embedded into the PS-based device. The PC 12 cells had better adherence on the PS devices, as compared to use of PDMS. Potassium-stimulation resulted in the release of 114 ± 11 µM catecholamines, a significant increase (p < 0.05) over the release from cells that had been exposed to an inhibitor (reserpine, 20 ± 2 µM of catecholamines). The ability to successfully measure multiple analytes, generated in different means from various cells under investigation, suggests that PS may be a useful material for microfluidic device fabrication, especially considering the enhanced cell adhesion to PS, its enhanced rigidity/amenability to automation, and its ability to enable a wider range of

  5. 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.

  6. 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.

  7. A microfluidic device with pillars

    DEFF Research Database (Denmark)

    2014-01-01

    The invention provides a microfluidic device for mixing liquid reagents, the device comprises, a chip forming at least one reaction chamber between a bottom and a top and extending between an inlet and an outlet. To enable manufacturing from less rigid materials, the device comprises pillars...

  8. A laser-based technology for fabricating a soda-lime glass based microfluidic device for circulating tumour cell capture.

    Science.gov (United States)

    Nieto, Daniel; Couceiro, Ramiro; Aymerich, Maria; Lopez-Lopez, Rafael; Abal, Miguel; Flores-Arias, María Teresa

    2015-10-01

    We developed a laser-based technique for fabricating microfluidic microchips on soda-lime glass substrates. The proposed methodology combines a laser direct writing, as a manufacturing tool for the fabrication of the microfluidics structures, followed by a post-thermal treatment with a CO2 laser. This treatment will allow reshaping and improving the morphological (roughness) and optical qualities (transparency) of the generated microfluidics structures. The use of lasers commonly implemented for material processing makes this technique highly competitive when compared with other glass microstructuring approaches. The manufactured chips were tested with tumour cells (Hec 1A) after being functionalized with an epithelial cell adhesion molecule (EpCAM) antibody coating. Cells were successfully arrested on the pillars after being flown through the device giving our technology a translational application in the field of cancer research. PMID:26218523

  9. Surface Modified Thread-Based Microfluidic Analytical Device for Selective Potassium Analysis.

    Science.gov (United States)

    Erenas, Miguel M; de Orbe-Payá, Ignacio; Capitan-Vallvey, Luis Fermin

    2016-05-17

    This paper presents a thread-based microfluidic device (μTAD) that includes ionophore extraction chemistry for the optical recognition of potassium. The device is 1.5 cm × 1.0 cm and includes a cotton thread to transport the aqueous sample via capillary wicking to a 5 mm-long detection area, where the recognition chemistry is deposited that reaches equilibrium in 60 s, changing its color between blue and magenta. A complete characterization of the cotton thread used as well as the sensing element has been carried out. The imaging of the μTAD with a digital camera and the extraction of the H coordinate of the HSV color space used as the analytical parameter make it possible to determine K(I) between 2.4 × 10(-5) and 0.95 M with a precision better than 1.3%. PMID:27077212

  10. A portable microfluidic fluorescence spectrometer device for {gamma}-H2AX-based biological dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Pope, I.A.; Barber, P.R. [Gray Institute for Radiation Oncology and Biology, University of Oxford, Oxford (United Kingdom); Horn, S.; Ainsbury, E. [Health Protection Agency Centre for Radiation, Chemical and Environmental Hazards, Chilton, Didcot OX11 0RQ, Oxon (United Kingdom); Rothkamm, K., E-mail: kai.rothkamm@hpa.org.uk [Health Protection Agency Centre for Radiation, Chemical and Environmental Hazards, Chilton, Didcot OX11 0RQ, Oxon (United Kingdom); Vojnovic, B. [Gray Institute for Radiation Oncology and Biology, University of Oxford, Oxford (United Kingdom)

    2011-09-15

    Following a radiological incident the rapid identification of those individuals exposed to critically high radiation doses is important for initial triage and medical treatment. It has been previously demonstrated that scoring of radiation-induced foci of the phosphorylated histone {gamma}-H2AX, which form at the sites of DNA double-strand breaks, may be used to determine radiation exposure levels from blood samples. Although faster than the 'gold standard' dicentric assay, foci scoring is still impractical in a field situation where large numbers of people may need to be screened. To deal with such a situation, an inexpensive portable device with high throughput capacity is desirable. Here we describe a portable microfluidic fluorescence spectrometer device which passes a suspension of {gamma}-H2AX immunofluorescence-stained lymphocytes through a focused 488 nm laser beam in a microfluidic chamber and records emission spectra over the range 495-725 nm. The recorded emission spectra are spectrally unmixed into their constituent parts from which radiation exposure levels are determined. Proof of principle is demonstrated using cultured lymphoblastoid cells, exposed to X-ray doses between 0 and 8 Gy. With the current prototype setup it takes approximately 6 min to acquire and analyse 10,000 spectra. Further effort is required to fully develop this approach into a portable triage tool that could be used to help classify people into appropriate treatment categories based on radiation exposure levels.

  11. A polystyrene-based microfluidic device with three-dimensional interconnected microporous walls for perfusion cell culture

    Science.gov (United States)

    Chan, Chung Yu; Goral, Vasiliy N.; DeRosa, Michael E.; Huang, Tony Jun

    2014-01-01

    In this article, we present a simple, rapid prototyped polystyrene-based microfluidic device with three-dimensional (3D) interconnected microporous walls for long term perfusion cell culture. Patterned 3D interconnected microporous structures were created by a chemical treatment together with a protective mask and the native hydrophobic nature of the microporous structures were selectively made hydrophilic using oxygen plasma treatment together with a protective mask. Using this polystyrene-based cell culture microfluidic device, we successfully demonstrated the support of four days perfusion cell culture of hepatocytes (C3A cells). PMID:25379110

  12. Integrated microfluidic device for droplet manipulation

    OpenAIRE

    Basova, E.

    2013-01-01

    Droplets based microfluidic systems have a big potential for the miniaturization of processes for bioanalysis. In the form of droplets, reagents are used in discrete volume, enabling high-throughput chemical reactions as well as single-cell encapsulation. Microreactors of this type can be manipulated and applied in bio-testing. In this work we present a platform for droplet generation and manipulation by using dielectrophoresis force. This platform is an integrated microfluidic device wit...

  13. INTEGRATED MICROFLUIDIC DEVICE FOR DROPLET MANIPULATION

    OpenAIRE

    Basova Evgenia; Drs Jakub; Zemanek Jiri; Hurak Zdenek; Foret František

    2013-01-01

    Droplets based microfluidic systems have a big potential for the miniaturization of processes for bioanalysis. In the form of droplets, reagents are used in discrete volume, enabling high-throughput chemical reactions as well as single-cell encapsulation. Microreactors of this type can be manipulated and applied in bio-testing. In this work we present a platform for droplet generation and manipulation by using dielectrophoresis force. This platform is an integrated microfluidic device wit...

  14. Development of PDMS-based Microfluidic Device for Cell-based Assays

    Institute of Scientific and Technical Information of China (English)

    LI Chenuk-Wing; YANG Jun; TZANG Chi-Hung; YANG Meng-Su

    2004-01-01

    In a single step photolithography, muhi-level microfluidic device is fabricated by printing novel architectures on a film photomasks. The whole fabrication process is executed by classical PCB technology without the need to access clean room facilities. Different levels of protruding features on PCB master are produced by exposing a photomask with specifically arranged "windows and rims" architectures, followed by chemical wet etching. Poly(dimethylsiloxane)(PDMS) is then molded against the positive relief master to generate microfluidic device featured with multi-level sandbag structure and peripheral microchannels. This sandbag structure is an analog to traditional dam or weir for particle entrapment. The microstructure does not collapse when subjected to applied pressure, which is suitable for operation on elastic PDMS substrate.Typical immunocytochemcial staining assays were performed in the microdevice to demonstrate the applicability of the sandbag structure for cellular analysis. This simplified microfabrication process employs low-cost materials and minimal specialized equipment and can reproducibly produce mask lines with about 20 μm in width, which is sufficient for most microfluidic applications.

  15. Mixing in a Microfluid Device

    DEFF Research Database (Denmark)

    Hjorth, Poul G.; Deryabin, Mikhail

    Mixing of fluids in microchannels cannot rely on turbulence since the flow takes place at extremly low Reynolds numbers. Various active and passive devices have been developed to induce mixing in microfluid flow devices. We describe here a model of an active mixer where a transverse periodic flow...

  16. An integrated hybrid microfluidic device for oviposition-based chemical screening of adult Drosophila melanogaster.

    Science.gov (United States)

    Leung, Jacob C K; Hilliker, Arthur J; Rezai, Pouya

    2016-02-21

    Chemical screening using Drosophila melanogaster (the fruit fly) is vital in drug discovery, agricultural, and toxicological applications. Oviposition (egg laying) on chemically-doped agar plates is an important read-out metric used to quantitatively assess the biological fitness and behavioral responses of Drosophila. Current oviposition-based chemical screening studies are inaccurate, labor-intensive, time-consuming, and inflexible due to the manual chemical doping of agar. In this paper, we have developed a novel hybrid agar-polydimethylsiloxane (PDMS) microfluidic device for single- and multi-concentration chemical dosing and on-chip oviposition screening of free-flying adult stage Drosophila. To achieve this, we have devised a novel technique to integrate agar with PDMS channels using ice as a sacrificial layer. Subsequently, we have conducted single-chemical toxicity and multiple choice chemical preference assays on adult Drosophila melanogaster using zinc and acetic acid at various concentrations. Our device has enabled us to 1) demonstrate that Drosophila is capable of sensing the concentration of different chemicals on a PDMS-agar microfluidic device, which plays significant roles in determining oviposition site selection and 2) investigate whether oviposition preference differs between single- and multi-concentration chemical environments. This device may be used to study fundamental and applied biological questions in Drosophila and other egg laying insects. It can also be extended in design to develop sophisticated and dynamic chemical dosing and high-throughput screening platforms in the future that are not easily achievable with the existing oviposition screening techniques. PMID:26768402

  17. Facile fabrication processes for hydrogel-based microfluidic devices made of natural biopolymers

    Science.gov (United States)

    Yajima, Yuya; Yamada, Masumi; Yamada, Emi; Iwase, Masaki; Seki, Minoru

    2014-01-01

    We present facile strategies for the fabrication of two types of microfluidic devices made of hydrogels using the natural biopolymers, alginate, and gelatin as substrates. The processes presented include the molding-based preparation of hydrogel plates and their chemical bonding. To prepare calcium-alginate hydrogel microdevices, we suppressed the volume shrinkage of the alginate solution during gelation using propylene glycol alginate in the precursor solution along with sodium alginate. In addition, a chemical bonding method was developed using a polyelectrolyte membrane of poly-L-lysine as the electrostatic glue. To prepare gelatin-based microdevices, we used microbial transglutaminase to bond hydrogel plates chemically and to cross-link and stabilize the hydrogel matrix. As an application, mammalian cells (fibroblasts and vascular endothelial cells) were cultivated on the microchannel surface to form three-dimensional capillary-embedding tissue models for biological research and tissue engineering. PMID:24803964

  18. A low-cost, ultraflexible cloth-based microfluidic device for wireless electrochemiluminescence application.

    Science.gov (United States)

    Liu, Min; Liu, Rui; Wang, Dan; Liu, Cuiling; Zhang, Chunsun

    2016-08-01

    The rising need for low-cost diagnostic devices has led to the search for inexpensive matrices that allow performing alternative analytical assays. Cloth is a viable material for the development of analytical devices due to its low material and manufacture costs, ability to wick assay fluids by capillary forces, and potential for patterning multiplexed channel geometries. In this paper, we describe the construction of low-cost, ultraflexible microfluidic cloth-based analytical devices (μCADs) for wireless electrochemiluminescence based on closed bipolar electrodes (C-WL-ECL), employing extremely cheap materials and a manufacturing process. The C-WL-ECL μCADs are built with wax-screen-printed cloth channels and carbon ink screen-printed electrodes, and the estimated cost per device is only $0.015. To demonstrate the performance of C-WL-ECL μCADs, the two most commonly used ECL systems - tris(2,2'-bipyridyl)ruthenium(ii)/tri-n-propylamine (Ru(bpy)3(2+)/TPA) and 3-aminophthalhydrazide/hydrogen peroxide (luminol/H2O2) - are applied. Under optimized conditions, the C-WL-ECL method has successfully fulfilled the quantitative determination of TPA with a detection limit of 0.085 mM. In addition, on the bent μCADs (bending angle (θ) = 180°), the luminol/H2O2-based ECL system can detect H2O2 as low as 0.024 mM. Based on such an ECL system, the bent μCADs are further used for determination of glucose in a phosphate buffer solution (PBS), with the detection limit of 0.195 mM. Finally, the applicability and validity, anti-interference ability, and storage stability of the C-WL-ECL μCADs are investigated. The results indicate that the proposed device has shown potential to extend the use of microfluidic analytical devices, due to its simplicity, low cost, ultraflexibility, and acceptable analytical performance. PMID:27356231

  19. A Simple Paper-Based Microfluidic Device for the Determination of the Total Amino Acid Content in a Tea Leaf Extract

    Science.gov (United States)

    Cai, Longfei; Wu, Yunying; Xu, Chunxiu; Chen, Zefeng

    2013-01-01

    An experiment was developed to demonstrate a microfluidic device in the analytical chemistry (instrumental analysis) laboratory. Students made the paper-based microfluidic device with a wax pen and a piece of filter paper and used it to determine the total quantity of amino acids in a green tea leaf

  20. Tabu Search-based Synthesis of Digital Microfluidic Biochips with Dynamically Reconfigurable Non-rectangular Devices

    DEFF Research Database (Denmark)

    Maftei, Elena; Pop, Paul; Madsen, Jan

    2010-01-01

    . In our approach, we consider changing the device to which an operation is bound during its execution, to improve the completion time of the biochemical application. Moreover, we devise an analytical method for determining the completion time of an operation on a device of any given shape. The proposed......Microfluidic biochips are replacing the conventional biochemical analyzers, and are able to integrate on-chip all the necessary functions for biochemical analysis. The "digital" microfluidic biochips are manipulating liquids not as a continuous flow, but as discrete droplets, and hence...... rectangular. In this paper, we present a Tabu Search metaheuristic for the synthesis of digital microfluidic biochips, which, starting from a biochemical application and a given biochip architecture, determines the allocation, resource binding, scheduling and placement of the operations in the application...

  1. Advances in Microfluidic Paper-Based Analytical Devices for Food and Water Analysis

    Directory of Open Access Journals (Sweden)

    Lori Shayne Alamo Busa

    2016-05-01

    Full Text Available Food and water contamination cause safety and health concerns to both animals and humans. Conventional methods for monitoring food and water contamination are often laborious and require highly skilled technicians to perform the measurements, making the quest for developing simpler and cost-effective techniques for rapid monitoring incessant. Since the pioneering works of Whitesides’ group from 2007, interest has been strong in the development and application of microfluidic paper-based analytical devices (μPADs for food and water analysis, which allow easy, rapid and cost-effective point-of-need screening of the targets. This paper reviews recently reported μPADs that incorporate different detection methods such as colorimetric, electrochemical, fluorescence, chemiluminescence, and electrochemiluminescence techniques for food and water analysis.

  2. Fabrication of PDMS-Based Microfluidic Devices: Application for Synthesis of Magnetic Nanoparticles

    Science.gov (United States)

    Thu, Vu Thi; Mai, An Ngoc; Le The Tam; Van Trung, Hoang; Thu, Phung Thi; Tien, Bui Quang; Thuat, Nguyen Tran; Lam, Tran Dai

    2016-05-01

    In this work, we have developed a convenient approach to synthesize magnetic nanoparticles with relatively high magnetization and controllable sizes. This was realized by combining the traditional co-precipitation method and microfluidic techniques inside microfluidic devices. The device was first designed, and then fabricated using simplified soft-lithography techniques. The device was utilized to synthesize magnetite nanoparticles. The synthesized nanomaterials were thoroughly characterized using field emission scanning electron microscopy and a vibrating sample magnetometer. The results demonstrated that the as-prepared device can be utilized as a simple and effective tool to synthesize magnetic nanoparticles with the sizes less than 10 nm and magnetization more than 50 emu/g. The development of these devices opens new strategies to synthesize nanomaterials with more precise dimensions at narrow size-distribution and with controllable behaviors.

  3. Microfluidic devices for droplet injection

    Science.gov (United States)

    Aubrecht, Donald; Akartuna, Ilke; Weitz, David

    2012-02-01

    As picoliter-scale reaction vessels, microfluidic water-in-oil emulsions have found application for high-throughput, large-sample number analyses. Often, the biological or chemical system under investigation needs to be encapsulated into droplets to prevent cross contamination prior to the introduction of reaction reagents. Previous techniques of picoinjection or droplet synchronization and merging enable the addition of reagents to individual droplets, but present limitations on what can be added to each droplet. We present microfluidic devices that couple the strengths of picoinjection and droplet merging, allowing us to selectively add precise volume to our droplet reactions.

  4. Osteocyte culture in microfluidic devices

    OpenAIRE

    Wei, Chao; Fan, Beiyuan; Chen, Deyong; Liu, Chao; Wei, Yuanchen; Huo, Bo; You, Lidan; Wang, Junbo; Chen, Jian

    2015-01-01

    This paper presents a microfluidic device (poly-dimethylsiloxane micro channels bonded with glass slides) enabling culture of MLO-Y4 osteocyte like cells. In this study, on-chip collagen coating, cell seeding and culture, as well as staining were demonstrated in a tubing-free manner where gravity was used as the driving force for liquid transportation. MLO-Y4 cells were cultured in microfluidic channels with and without collagen coating where cellular images in a time sequence were taken and ...

  5. Understanding wax screen-printing: a novel patterning process for microfluidic cloth-based analytical devices.

    Science.gov (United States)

    Liu, Min; Zhang, Chunsun; Liu, Feifei

    2015-09-01

    In this work, we first introduce the fabrication of microfluidic cloth-based analytical devices (μCADs) using a wax screen-printing approach that is suitable for simple, inexpensive, rapid, low-energy-consumption and high-throughput preparation of cloth-based analytical devices. We have carried out a detailed study on the wax screen-printing of μCADs and have obtained some interesting results. Firstly, an analytical model is established for the spreading of molten wax in cloth. Secondly, a new wax screen-printing process has been proposed for fabricating μCADs, where the melting of wax into the cloth is much faster (∼5 s) and the heating temperature is much lower (75 °C). Thirdly, the experimental results show that the patterning effects of the proposed wax screen-printing method depend to a certain extent on types of screens, wax melting temperatures and melting time. Under optimized conditions, the minimum printing width of hydrophobic wax barrier and hydrophilic channel is 100 μm and 1.9 mm, respectively. Importantly, the developed analytical model is also well validated by these experiments. Fourthly, the μCADs fabricated by the presented wax screen-printing method are used to perform a proof-of-concept assay of glucose or protein in artificial urine with rapid high-throughput detection taking place on a 48-chamber cloth-based device and being performed by a visual readout. Overall, the developed cloth-based wax screen-printing and arrayed μCADs should provide a new research direction in the development of advanced sensor arrays for detection of a series of analytes relevant to many diverse applications.

  6. Tetrazine-based chemistry for nitrite determination in a paper microfluidic device.

    Science.gov (United States)

    Ortiz-Gomez, Inmaculada; Ortega-Muñoz, Mariano; Salinas-Castillo, Alfonso; Álvarez-Bermejo, José Antonio; Ariza-Avidad, Maria; de Orbe-Payá, Ignacio; Santoyo-Gonzalez, Francisco; Capitan-Vallvey, Luis Fermin

    2016-11-01

    We present a new chemistry to determine nitrites implemented in a microfluidic paper-based analytical device (µPAD). The device is fabricated in cellulose paper with a sample reception area and three replicate detection areas with recognition chemistry immobilized by adsorption. The method involves the use of nitrite in an acid medium reaction to generate nitrous acid, which produces the oxidation of s-dihydrotetrazine: 1,2-dihydro-3,6-bis(3,5-dimethyl-1H-pyrazol-1-yl)-1,2,4,5-tetrazine (DHBPTz), which change the detection zone from colorless to pink. We used a digital camera and smartphone for the quantitative analysis of nitrite with the color coordinate S of the HSV color space as the analytical parameter. Parameters such as concentration and volume of s-dihydrotetrazine, pH, sample volume and reaction time were studied. The detection limit for this method is 1.30µM nitrite. To estimate the selectivity of the method an interference study of common ions in water samples was performed. The procedure was applied to natural water and compared with reference procedures. PMID:27591668

  7. Tetrazine-based chemistry for nitrite determination in a paper microfluidic device.

    Science.gov (United States)

    Ortiz-Gomez, Inmaculada; Ortega-Muñoz, Mariano; Salinas-Castillo, Alfonso; Álvarez-Bermejo, José Antonio; Ariza-Avidad, Maria; de Orbe-Payá, Ignacio; Santoyo-Gonzalez, Francisco; Capitan-Vallvey, Luis Fermin

    2016-11-01

    We present a new chemistry to determine nitrites implemented in a microfluidic paper-based analytical device (µPAD). The device is fabricated in cellulose paper with a sample reception area and three replicate detection areas with recognition chemistry immobilized by adsorption. The method involves the use of nitrite in an acid medium reaction to generate nitrous acid, which produces the oxidation of s-dihydrotetrazine: 1,2-dihydro-3,6-bis(3,5-dimethyl-1H-pyrazol-1-yl)-1,2,4,5-tetrazine (DHBPTz), which change the detection zone from colorless to pink. We used a digital camera and smartphone for the quantitative analysis of nitrite with the color coordinate S of the HSV color space as the analytical parameter. Parameters such as concentration and volume of s-dihydrotetrazine, pH, sample volume and reaction time were studied. The detection limit for this method is 1.30µM nitrite. To estimate the selectivity of the method an interference study of common ions in water samples was performed. The procedure was applied to natural water and compared with reference procedures.

  8. Raman Characterization of Nanoparticle Transport in Microfluidic Paper-Based Analytical Devices (μPADs).

    Science.gov (United States)

    Lahr, Rebecca Halvorson; Wallace, Grant C; Vikesland, Peter J

    2015-05-01

    There is great interest in the use of microfluidic paper-based analytical devices (μPADs) for low-cost diagnostics. In this contribution, we illustrate the utility of Raman spectral imaging for both μPAD characterization and for quantification of the transport of applied reagents and analytes within these devices. We evaluated the transport of nanoscale particles within μPADs using a suite of differentially functionalized gold (AuNP) and silver (AgNP) nanoparticles with diameters of 8-64 nm. Nanoparticle transport within the cellulose matrix was characterized by collection of both Raman and surface-enhanced Raman spectroscopy (SERS) spectral maps that enabled differentiation of cellulose fibers and characterization of analyte deposition patterns. The transport of citrate (cit), BSA, PEG, PVP, and DNA functionalized AuNP and AgNP in wax-printed μPADs was primarily affected by nanoparticle surface chemistry rather than particle size or core composition. Sample pH (3-10) influenced the transport of 15 nm BSA-cit-AuNP, but not 15 nm cit-AuNP, because of the effects of solution pH on the charge and conformation of BSA. Derjaguin, Landau, Verwey, and Overbeek theory (DLVO) and extended DLVO (xDLVO) theory are used to explain the collected experimental results. PMID:25853463

  9. Integrated separation of blood plasma from whole blood for microfluidic paper-based analytical devices.

    Science.gov (United States)

    Yang, Xiaoxi; Forouzan, Omid; Brown, Theodore P; Shevkoplyas, Sergey S

    2012-01-21

    Many diagnostic tests in a conventional clinical laboratory are performed on blood plasma because changes in its composition often reflect the current status of pathological processes throughout the body. Recently, a significant research effort has been invested into the development of microfluidic paper-based analytical devices (μPADs) implementing these conventional laboratory tests for point-of-care diagnostics in resource-limited settings. This paper describes the use of red blood cell (RBC) agglutination for separating plasma from finger-prick volumes of whole blood directly in paper, and demonstrates the utility of this approach by integrating plasma separation and a colorimetric assay in a single μPAD. The μPAD was fabricated by printing its pattern onto chromatography paper with a solid ink (wax) printer and melting the ink to create hydrophobic barriers spanning through the entire thickness of the paper substrate. The μPAD was functionalized by spotting agglutinating antibodies onto the plasma separation zone in the center and the reagents of the colorimetric assay onto the test readout zones on the periphery of the device. To operate the μPAD, a drop of whole blood was placed directly onto the plasma separation zone of the device. RBCs in the whole blood sample agglutinated and remained in the central zone, while separated plasma wicked through the paper substrate into the test readout zones where analyte in plasma reacted with the reagents of the colorimetric assay to produce a visible color change. The color change was digitized with a portable scanner and converted to concentration values using a calibration curve. The purity and yield of separated plasma was sufficient for successful operation of the μPAD. This approach to plasma separation based on RBC agglutination will be particularly useful for designing fully integrated μPADs operating directly on small samples of whole blood.

  10. Fabrication techniques for microfluidic paper-based analytical devices and their applications for biological testing: A review.

    Science.gov (United States)

    Xia, Yanyan; Si, Jin; Li, Zhiyang

    2016-03-15

    Paper is increasingly recognized as a user-friendly and ubiquitous substrate for construction of microfluidic devices. Microfluidic paper-based analytical devices (μPADs) provide an alternative technology for development of affordable, portable, disposable and low-cost diagnostic tools for improving point of care testing (POCT) and disease screening in the developing world, especially in those countries with no- or low-infrastructure and limited trained medical and health professionals. We in this review present fabrication techniques for microfluidic devices and their respective applications for biological detection as reported to date. These include: (i) fabrication techniques: examples of devices fabricated by using two-dimensional (2D) and three-dimensional (3D) methods; (ii) detection application: biochemical, immunological and molecular detection by incorporating efficient detection methods such as, colorimetric detection, electrochemical detection, fluorescence detection, chemiluminescence (CL) detection, electrochemiluninescence (ECL) detection, photoelectrochemi (PEC) detection and so on. In addition, main advantages, disadvantages and future trends for the devices are also discussed in this review.

  11. Reduction in microparticle adsorption using a lateral interconnection method in a PDMS-based microfluidic device.

    Science.gov (United States)

    Lee, Do-Hyun; Park, Je-Kyun

    2013-12-01

    Microparticle adsorption on microchannel walls occurs frequently due to nonspecific interactions, decreasing operational performance in pressure-driven microfluidic systems. However, it is essential for delicate manipulation of microparticles or cells to maintain smooth fluid traffic. Here, we report a novel microparticle injection technique, which prevents particle loss, assisted by sample injection along the direction of fluid flow. Sample fluids, including microparticles, mammalian (U937), and green algae (Chlorella vulgaris) cells, were injected directly via a through hole drilled in the lateral direction, resulting in a significant reduction in microparticle attachment. For digital microfluidic application, the proposed regime achieved a twofold enhancement of single-cell encapsulation compared to the conventional encapsulation rate, based on a Poisson distribution, by reducing the number of empty droplets. This novel interconnection method can be straightforwardly integrated as a microparticle or cell injection component in integrated microfluidic systems.

  12. Charge-based particle separation in microfluidic devices using combined hydrodynamic and electrokinetic effects

    NARCIS (Netherlands)

    Jellema, L. C.; Mey, T.; Koster, S.; Verpoorte, E.

    2009-01-01

    A new microfluidic approach for charge-based particle separation using combined hydrodynamic and electrokinetic effects is presented. A recirculating flow pattern is employed, generated through application of bi-directional flow in a narrow glass microchannel incorporating diverging or converging se

  13. Perfused drop microfluidic device for brain slice culture-based drug discovery.

    Science.gov (United States)

    Liu, Jing; Pan, Liping; Cheng, Xuanhong; Berdichevsky, Yevgeny

    2016-06-01

    Living slices of brain tissue are widely used to model brain processes in vitro. In addition to basic neurophysiology studies, brain slices are also extensively used for pharmacology, toxicology, and drug discovery research. In these experiments, high parallelism and throughput are critical. Capability to conduct long-term electrical recording experiments may also be necessary to address disease processes that require protein synthesis and neural circuit rewiring. We developed a novel perfused drop microfluidic device for use with long term cultures of brain slices (organotypic cultures). Slices of hippocampus were placed into wells cut in polydimethylsiloxane (PDMS) film. Fluid level in the wells was hydrostatically controlled such that a drop was formed around each slice. The drops were continuously perfused with culture medium through microchannels. We found that viable organotypic hippocampal slice cultures could be maintained for at least 9 days in vitro. PDMS microfluidic network could be readily integrated with substrate-printed microelectrodes for parallel electrical recordings of multiple perfused organotypic cultures on a single MEA chip. We expect that this highly scalable perfused drop microfluidic device will facilitate high-throughput drug discovery and toxicology. PMID:27194028

  14. Chelate titrations of Ca(2+) and Mg(2+) using microfluidic paper-based analytical devices.

    Science.gov (United States)

    Karita, Shingo; Kaneta, Takashi

    2016-06-14

    We developed microfluidic paper-based analytical devices (μPADs) for the chelate titrations of Ca(2+) and Mg(2+) in natural water. The μPAD consisted of ten reaction zones and ten detection zones connected through narrow channels to a sample zone located at the center. Buffer solutions with a pH of 10 or 13 were applied to all surfaces of the channels and zones. Different amounts of ethylenediaminetetraacetic acid (EDTA) were added to the reaction zones and a consistent amount of a metal indicator (Eriochrome Black T or Calcon) was added to the detection zones. The total concentrations of Ca(2+) and Mg(2+) (total hardness) in the water were measured using a μPAD containing a buffer solution with a pH of 10, whereas only Ca(2+) was titrated using a μPAD prepared with a potassium hydroxide solution with a pH of 13. The μPADs permitted the determination of Ca(2+) and Mg(2+) in mineral water, river water, and seawater samples within only a few minutes using only the naked eye-no need of instruments.

  15. Chelate titrations of Ca(2+) and Mg(2+) using microfluidic paper-based analytical devices.

    Science.gov (United States)

    Karita, Shingo; Kaneta, Takashi

    2016-06-14

    We developed microfluidic paper-based analytical devices (μPADs) for the chelate titrations of Ca(2+) and Mg(2+) in natural water. The μPAD consisted of ten reaction zones and ten detection zones connected through narrow channels to a sample zone located at the center. Buffer solutions with a pH of 10 or 13 were applied to all surfaces of the channels and zones. Different amounts of ethylenediaminetetraacetic acid (EDTA) were added to the reaction zones and a consistent amount of a metal indicator (Eriochrome Black T or Calcon) was added to the detection zones. The total concentrations of Ca(2+) and Mg(2+) (total hardness) in the water were measured using a μPAD containing a buffer solution with a pH of 10, whereas only Ca(2+) was titrated using a μPAD prepared with a potassium hydroxide solution with a pH of 13. The μPADs permitted the determination of Ca(2+) and Mg(2+) in mineral water, river water, and seawater samples within only a few minutes using only the naked eye-no need of instruments. PMID:27181645

  16. Detection of distributed static and dynamic loads with electrolyte-enabled distributed transducers in a polymer-based microfluidic device

    International Nuclear Information System (INIS)

    This paper reports on the use of electrolyte-enabled distributed transducers in a polymer-based microfluidic device for the detection of distributed static and dynamic loads. The core of the device is a polymer rectangular microstructure integrated with electrolyte-enabled distributed transducers. Distributed loads acting on the polymer microstructure are converted to different deflections along the microstructure length, which are further translated to electrical resistance changes by electrolyte-enabled distributed transducers. Owing to the great simplicity of the device configuration, a standard polymer-based fabrication process is employed to fabricate this device. With custom-built electronic circuits and custom LabVIEW programs, fabricated devices filled with two different electrolytes, 0.1 M NaCl electrolyte and 1-ethyl-3-methylimidazolium dicyanamide electrolyte, are characterized, demonstrating the capability of detecting distributed static and dynamic loads with a single device. As a result, the polymer-based microfluidic device presented in this paper is promising for offering the capability of detecting distributed static and dynamic loads in biomedical/surgical, manufacturing and robotics applications. (paper)

  17. OPTIMIZATION OF A MICROFLUIDIC DEVICE FOR DIFFUSION-BASED EXTRACTION OF DMSO FROM A CELL SUSPENSION

    OpenAIRE

    Fleming Glass, K. K.; Longmire, E. K.; Hubel, A.

    2008-01-01

    This study considers the use of a two-stream microfluidic device for extraction of dimethyl sulphoxide (DMSO) from a cryopreserved cell suspension. The DMSO diffuses from a cell suspension stream into a neighboring wash stream flowing in parallel. The model of Fleming et al.[14] is employed to determine and discuss optimal geometry and operating conditions for a case requiring removal of 95% DMSO from suspension streams with volumetric flow rates up to 2.5 ml/min. The effects of Peclet number...

  18. Integrated lenses in polystyrene microfluidic devices

    KAUST Repository

    Fan, Yiqiang

    2013-04-01

    This paper reports a new method for integrating microlenses into microfluidic devices for improved observation. Two demonstration microfluidic devices were provided which were fabricated using this new technique. The integrated microlenses were fabricated using a free-surface thermo-compression molding method on a polystyrene (PS) sheet which was then bonded on top of microfluidic channels as a cover plate, with the convex microlenses providing a magnified image of the channel for the easier observation of the flow in the microchannels. This approach for fabricating the integrated microlens in microfluidic devices is rapid, low cost and without the requirement of cleanroom facilities. © 2013 IEEE.

  19. Microfluidic device capable of sensing ultrafast chemiluminescence.

    Science.gov (United States)

    Kim, Young-Teck; Ko, Seok Oh; Lee, Ji Hoon

    2009-05-15

    Based on the principle of liquid core waveguide, a novel microfluidic device with micro-scale detection window capable of sensing flashlight emitted from rapid 1,1'-oxalyldi-4-methylimidazole (OD4MI) chemiluminescence (CL) reaction was fabricated. Light emitted from OD4MI CL reaction occurring in the micro-dimensional pentagonal detection window (length of each line segment: 900.0 microm, depth: 50.0 microm) of the microfluidic device with two inlets and one outlet was so bright that it was possible to take an image every 1/30 s at the optimal focusing distance (60 cm) using a commercial digital camera. Peaks obtained using a flow injection analysis (FIA) system with the micro-scale detection window and OD4MI CL detection show excellent resolution and reproducibility without any band-broadening observed in analytical devices having additional reaction channel(s) to measure light generated from slow CL reaction. Maximum height (H(max)) and area (A) of peak, reproducibility and sensitivity observed in the FIA system with the microfluidic device and OD4MI CL detection depends on (1) the mole ratio between bis(2,4,6-trichlorophenyl) oxalate and 4-methyl imidazole yielding OD4MI, (2) the flow rate to mix OD4MI, H(2)O(2) and 1-AP in the detection window of the microfluidic device, and (3) H(2)O(2) concentration. We obtained linear calibration curves with wide dynamic ranges using H(max) and A. The detection limit of 1-AP determined with H(max) and A was as low as 0.05 fmole/injection (signal/background=3.0). PMID:19269463

  20. Development of a microfluidic paper-based analytical device for the determination of salivary aldehydes.

    Science.gov (United States)

    Ramdzan, Adlin N; Almeida, M Inês G S; McCullough, Michael J; Kolev, Spas D

    2016-05-01

    A low cost, disposable and easy to use microfluidic paper-based analytical device (μPAD) was developed for simple and non-invasive determination of total aldehydes in saliva with a potential to be used in epidemiological studies to assess oral cancer risk. The μPAD is based on the colour reaction between aldehydes (e.g. acetaldehyde, formaldehyde), 3-methyl-2-benzothiazolinone hydrazone (MBTH) and iron(III) to form an intense blue coloured formazan dye. The newly developed μPAD has a 3D design with two overlapping paper layers. The first layer comprises 15 circular detection zones (8 mm in diameter), each impregnated with 8 μL of MBTH, while the second layer contains 15 reagent zones (4 mm in diameter). Two μL of iron(III) chloride are added to each one of the second layer zones after the addition of sample to the detection zones in the first layer. All hydrophilic zones of the μPAD are defined by wax printing using a commercial wax printer. Due to the 2-step nature of the analytical reaction, the two paper layers are separated by a cellulose acetate interleaving sheet to allow for the reaction between the aldehydes in the saliva sample with MBTH to proceed first with the formation of an azine, followed by a blue coloured reaction between the azine and the oxidized by iron(III) form of MBTH, produced after the removal of the interleaving sheet. After obtaining a high resolution image of the detection side zone of the device using a flatbed scanner, the intensity of the blue colour within each detection zone is measured with Image J software. Under optimal conditions, the μPAD is characterised by a working range of 20.4-114.0 μM, limit of detection of 6.1 μM, and repeatability, expressed as RSD, of less than 12.7% (n = 5). There is no statistically significant difference at the 95% confidence level between the results obtained by the μPAD and the reference method (Student's t-test: 0.090 < 0.38). The optimized μPAD is stable for more than 41 days

  1. Purification of microalgae from bacterial contamination using a disposable inertia-based microfluidic device

    Science.gov (United States)

    Godino, Neus; Jorde, Felix; Lawlor, Daryl; Jaeger, Magnus; Duschl, Claus

    2015-08-01

    Microalgae are a promising source of bioactive ingredients for the food, pharmaceutical and cosmetic industries. Every microalgae research group or production facility is facing one major problem regarding the potential contamination of the algal cell with bacteria. Prior to the storage of the microalgae in strain collections or to cultivation in bioreactors, it is necessary to carry out laborious purification procedures to separate the microalgae from the undesired bacterial cells. In this work, we present a disposable microfluidic cartridge for the high-throughput purification of microalgae samples based on inertial microfluidics. Some of the most relevant microalgae strains have a larger size than the relatively small, few micron bacterial cells, so making them distinguishable by size. The inertial microfluidic cartridge was fabricated with inexpensive materials, like pressure sensitive adhesive (PSA) and thin plastic layers, which were patterned using a simple cutting plotter. In spite of fabrication restrictions and the intrinsic difficulties of biological samples, the separation of microalgae from bacteria reached values in excess of 99%, previously only achieved using conventional high-end and high cost lithography methods. Moreover, due to the simple and high-throughput characteristic of the separation, it is possible to concatenate serial purification to exponentially decrease the absolute amount of bacteria in the final purified sample.

  2. Purification of microalgae from bacterial contamination using a disposable inertia-based microfluidic device

    International Nuclear Information System (INIS)

    Microalgae are a promising source of bioactive ingredients for the food, pharmaceutical and cosmetic industries. Every microalgae research group or production facility is facing one major problem regarding the potential contamination of the algal cell with bacteria. Prior to the storage of the microalgae in strain collections or to cultivation in bioreactors, it is necessary to carry out laborious purification procedures to separate the microalgae from the undesired bacterial cells. In this work, we present a disposable microfluidic cartridge for the high-throughput purification of microalgae samples based on inertial microfluidics. Some of the most relevant microalgae strains have a larger size than the relatively small, few micron bacterial cells, so making them distinguishable by size. The inertial microfluidic cartridge was fabricated with inexpensive materials, like pressure sensitive adhesive (PSA) and thin plastic layers, which were patterned using a simple cutting plotter. In spite of fabrication restrictions and the intrinsic difficulties of biological samples, the separation of microalgae from bacteria reached values in excess of 99%, previously only achieved using conventional high-end and high cost lithography methods. Moreover, due to the simple and high-throughput characteristic of the separation, it is possible to concatenate serial purification to exponentially decrease the absolute amount of bacteria in the final purified sample. (paper)

  3. A Disposable Microfluidic Virus Concentration Device Based on Evaporation and Interfacial Tension

    Directory of Open Access Journals (Sweden)

    Catherine M. Klapperich

    2013-02-01

    Full Text Available We report a disposable and highly effective polymeric microfluidic viral sample concentration device capable of increasing the concentration of virus in a human nasopharyngeal specimen more than one order of magnitude in less than 30 min without the use of a centrifuge. The device is fabricated using 3D maskless xurography method using commercially available polymeric materials, which require no cleanroom operations. The disposable components can be fabricated and assembled in five minutes. The device can concentrate a few milliliters (mL of influenza virus in solution from tissue culture or clinical nasopharyngeal swab specimens, via reduction of the fluid volume, to tens of microliters (mL. The performance of the device was evaluated by nucleic acid extraction from the concentrated samples, followed by a real-time quantitative polymerase chain reaction (qRT-PCR. The viral RNA concentration in each sample was increased on average over 10-fold for both cultured and patient specimens compared to the starting samples, with recovery efficiencies above 60% for all input concentrations. Highly concentrated samples in small fluid volumes can increase the downstream process speed of on-chip nucleic acid extraction, and result in improvements in the sensitivity of many diagnostic platforms that interrogate small sample volumes.

  4. Rapid and alternative fabrication method for microfluidic paper based analytical devices.

    Science.gov (United States)

    Malekghasemi, Soheil; Kahveci, Enver; Duman, Memed

    2016-10-01

    A major application of microfluidic paper-based analytical devices (µPADs) includes the field of point-of-care (POC) diagnostics. It is important for POC diagnostics to possess properties such as ease-of-use and low cost. However, µPADs need multiple instruments and fabrication steps. In this study, two different chemicals (Hexamethyldisilazane and Tetra-ethylorthosilicate) were used, and three different methods (heating, plasma treatment, and microwave irradiation) were compared to develop µPADs. Additionally, an inkjet-printing technique was used for generating a hydrophilic channel and printing certain chemical agents on different regions of a modified filter paper. A rapid and effective fabrication method to develop µPADs within 10min was introduced using an inkjet-printing technique in conjunction with a microwave irradiation method. Environmental scanning electron microscope (ESEM) and x-ray photoelectron spectroscopy (XPS) were used for morphology characterization and determining the surface chemical compositions of the modified filter paper, respectively. Contact angle measurements were used to fulfill the hydrophobicity of the treated filter paper. The highest contact angle value (141°±1) was obtained using the microwave irradiation method over a period of 7min, when the filter paper was modified by TEOS. Furthermore, by using this method, the XPS results of TEOS-modified filter paper revealed Si2p (23%) and Si-O bounds (81.55%) indicating the presence of Si-O-Si bridges and Si(OEt) groups, respectively. The ESEM results revealed changes in the porous structures of the papers and decreases in the pore sizes. Washburn assay measurements tested the efficiency of the generated hydrophilic channels in which similar water penetration rates were observed in the TEOS-modified filter paper and unmodified (plain) filter paper. The validation of the developed µPADs was performed by utilizing the rapid urease test as a model test system. The detection limit of

  5. Hot embossed polyethylene through-hole chips for bead-based microfluidic devices

    Science.gov (United States)

    Chou, Jie; Du, Nan; Ou, Tina; Floriano, Pierre N.; Christodoulides, Nicolaos; McDevitt, John T.

    2013-01-01

    Over the past decade, there has been a growth of interest in the translation of microfluidic systems into real-world clinical practice, especially for use in point-of-care or near patient settings. While initial fabrication advances in microfluidics involved mainly the etching of silicon and glass, the economics of scaling of these materials is not amendable for point-of-care usage where single-test applications forces cost considerations to be kept low and throughput high. As such, a materials base more consistent with point-of-care needs is required. In this manuscript, the fabrication of a hot embossed, through-hole low-density polyethylene ensembles derived from an anisotropically etched silicon wafer is discussed. This semi-opaque polymer that can be easily sterilized and recycled provides low background noise for fluorescence measurements and yields more affordable cost than other thermoplastics commonly used for microfluidic applications such as cyclic olefin copolymer (COC). To fabrication through-hole microchips from this alternative material for microfluidics, a fabrication technique that uses a high-temperature, high-pressure resistant mold is described. This aluminum-based epoxy mold, serving as the positive master mold for embossing, is casted over etched arrays of pyramidal pits in a silicon wafer. Methods of surface treatment of the wafer prior to casting and PDMS casting of the epoxy are discussed to preserve the silicon wafer for future use. Changes in the thickness of polyethylene are observed for varying embossing temperatures. The methodology described herein can quickly fabricate 20 disposable, single use chips in less than 30 minutes with the ability to scale up 4x by using multiple molds simultaneously. When coupled as a platform supporting porous bead sensors, as in the recently developed Programmable Bio-Nano-Chip, this bead chip system can achieve limits of detection, for the cardiac biomarker C-reactive protein, of 0.3 ng/mL, thereby

  6. Development and optimization of an integrated capillary-based opto-microfluidic device for chemiluminescence quantitative detection

    International Nuclear Information System (INIS)

    A capillary-action driven device amenable for integration of organic photodiodes (OPDs) was developed for monitoring parallel chemiluminescence (CL) reactions. Device characterization was conducted using finite element method (FEM) simulations. Definition of the simulation setup, dimensional optimization of the reaction chamber and overall geometrical characterization of the microfluidic device were the main simulation results. Furthermore, a non-uniform filling process was observed during the final simulation of the capillary device. Validation of this result and the proposed capillary-driven filling process was later confirmed by experimental results. Experimental testing performed on a single chamber defined an optimal exposure time to the luminescent substrate of 5 min, indicating a quick analyte detection time. Further tests using one chamber presented a linear relation between the signal-to-noise ratio and increasing concentrations of the protein used. A measured limit of detection of 28 nM was obtained for streptavidin. Regarding the tests performed on the whole device, acceptable values of 39 s ± 5 s were obtained for the luminescent substrate total filling times. Also, the microfluidic device showed the capability to perform a quantitative detection of the occurring CL reactions. Weaker optical signals, due to the occurrence of CL reactions, were detected in the chambers with a later filling process, as predicted by simulation results. Notwithstanding these results, the capillary-based device is promising for quantitative detection of proteins in future point-of-care systems, presenting an unprompted filling process and parallel quantitative detection capability. (paper)

  7. Dynamic monitoring of single cell lysis in an impedance-based microfluidic device.

    Science.gov (United States)

    Zhou, Ying; Basu, Srinjan; Laue, Ernest D; Seshia, Ashwin A

    2016-08-01

    A microfluidic device that is capable of trapping and sensing dynamic variations in the electrical properties of individual cells is demonstrated. The device is applied to the real-time recording of impedance measurements of mouse embryonic stem cells (mESCs) during the process of membrane lysis, with the resulting changes in the electrical properties of cells during this process being quantitatively tracked over time. It is observed that the impedance magnitude decreases dramatically after cell membrane lysis. A significant shift in the phase spectrum is also observed during the time course of this process. By fitting experimental data to physical models, the electrical parameters of cells can be extracted and parameter variations quantified during the process. In the cell lysis experiments, the equivalent conductivity of the cell membrane is found to increase significantly due to pore formation in the membrane during lysis. An increase in the specific capacitance of the membrane is also observed. On the other hand, the conductivity of the cytoplasm is observed to decrease, which may be explained the fact that excess water enters the cell through the gradual permeabilization of the membrane during lysis. Cells can be trapped in the device for periods up to several days, and their electrical response can be monitored by real-time impedance measurements in a label-free and non-invasive manner. Furthermore, due to the highly efficient single cell trapping capacity of the device, a number of cells can be trapped and held in separate wells for concurrent parallel experiments, allowing for the possibility of stepped parametric experiments and studying cell heterogeneity by combining measurements across the array. PMID:27299468

  8. Paper-based three-dimensional microfluidic device for monitoring of heavy metals with a camera cell phone.

    Science.gov (United States)

    Wang, Hu; Li, Ya-jie; Wei, Jun-feng; Xu, Ji-run; Wang, Yun-hua; Zheng, Guo-xia

    2014-05-01

    A 3D paper-based microfluidic device has been developed for colorimetric determination of selected heavy metals in water samples by stacking layers of wax patterned paper and double-sided adhesive tape. It has the capability of wicking fluids and distributing microliter volumes of samples from single inlet into affrays of detection zones without external pumps, thus a range of metal assays can be simply and inexpensively performed. We demonstrate a prototype of four sample inlets for up to four heavy metal assays each, with detection limits as follows: Cu (II) = 0.29 ppm, Ni(II) = 0.33 ppm, Cd (II) = 0.19 ppm, and Cr (VI) = 0.35 ppm, which provided quantitative data that were in agreement with values gained from atomic absorption. It has the ability to identify these four metals in mixtures and is immune to interferences from either nontoxic metal ions such as Na(I) and K(I) or components found in reservoir or beach water. With the incorporation of a portable detector, a camera mobile phone, this 3D paper-based microfluidic device should be useful as a simple, rapid, and on-site screening approach of heavy metals in aquatic environments. PMID:24618990

  9. 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.

  10. Microfluidic Devices in Advanced Caenorhabditis elegans Research.

    Science.gov (United States)

    Muthaiyan Shanmugam, Muniesh; Subhra Santra, Tuhin

    2016-01-01

    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. PMID:27490525

  11. 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. PMID:19615498

  12. Biomechanical analysis of cancerous and normal cells based on bulge generation in a microfluidic device.

    Science.gov (United States)

    Kim, Yu Chang; Park, Sang-Jin; Park, Je-Kyun

    2008-10-01

    This paper presents a new biomechanical analysis method for discrimination between cancerous and normal cells through compression by poly(dimethylsiloxane) (PDMS) membrane deflection in a microfluidic device. When a cell is compressed, cellular membrane will expand and then small bulges will appear on the peripheral cell membrane beyond the allowable strain. It is well known that the amount of F-actin in cancer cells is less than that of normal cells and bulges occur at the sites where cytoskeleton becomes detached from the membrane bilayer. Accordingly, we have demonstrated the difference of the bulge generation between breast cancer cells (MCF7) and normal cells (MCF10A). After excessive deformation, the bulges generated in MCF7 cells were not evenly distributed on the cell periphery. Contrary to this, the bulges of MCF10A cells showed an even distribution. In addition, the morphologies of bulges of MCF7 and MCF10A cells looked swollen protrusion and tubular protrusion, respectively. Peripheral strains at the moment of the bulge generation were also 72% in MCF7 and 46% in MCF10A. The results show that the bulge generation can be correlated with the cytoskeleton quantity inside the cell, providing the first step of a new biomechanical approach. PMID:18810292

  13. 3D-printed microfluidic devices.

    Science.gov (United States)

    Amin, Reza; Knowlton, Stephanie; Hart, Alexander; Yenilmez, Bekir; Ghaderinezhad, Fariba; Katebifar, Sara; Messina, Michael; Khademhosseini, Ali; Tasoglu, Savas

    2016-06-20

    Microfluidics is a flourishing field, enabling a wide range of biochemical and clinical applications such as cancer screening, micro-physiological system engineering, high-throughput drug testing, and point-of-care diagnostics. However, fabrication of microfluidic devices is often complicated, time consuming, and requires expensive equipment and sophisticated cleanroom facilities. Three-dimensional (3D) printing presents a promising alternative to traditional techniques such as lithography and PDMS-glass bonding, not only by enabling rapid design iterations in the development stage, but also by reducing the costs associated with institutional infrastructure, equipment installation, maintenance, and physical space. With the recent advancements in 3D printing technologies, highly complex microfluidic devices can be fabricated via single-step, rapid, and cost-effective protocols, making microfluidics more accessible to users. In this review, we discuss a broad range of approaches for the application of 3D printing technology to fabrication of micro-scale lab-on-a-chip devices.

  14. Microfluidic chip-capillary electrophoresis devices

    CERN Document Server

    Fung, Ying Sing; Du, Fuying; Guo, Wenpeng; Ma, Tongmei; Nie, Zhou; Sun, Hui; Wu, Ruige; Zhao, Wenfeng

    2015-01-01

    Capillary electrophoresis (CE) and microfluidic chip (MC) devices are relatively mature technologies, but this book demonstrates how they can be integrated into a single, revolutionary device that can provide on-site analysis of samples when laboratory services are unavailable. By introducing the combination of CE and MC technology, Microfluidic Chip-Capillary Electrophoresis Devices broadens the scope of chemical analysis, particularly in the biomedical, food, and environmental sciences.The book gives an overview of the development of MC and CE technology as well as technology that now allows

  15. Rapid quantification of live cell receptors using bioluminescence in a flow-based microfluidic device.

    Science.gov (United States)

    Ramji, Ramesh; Cheong, Cheong Fook; Hirata, Hiroaki; Rahman, Abdur Rub Abdur; Lim, Chwee Teck

    2015-02-25

    The number of receptors expressed by cells plays an important role in controlling cell signaling events, thus determining its behaviour, state and fate. Current methods of quantifying receptors on cells are either laborious or do not maintain the cells in their native form. Here, a method integrating highly sensitive bioluminescence, high precision microfluidics and small footprint of lensfree optics is developed to quantify cell surface receptors. This method is safe to use, less laborious, and faster than the conventional radiolabelling and near field scanning methods. It is also more sensitive than fluorescence based assays and is ideal for high throughput screening. In quantifying β(1) adrenergic receptors expressed on the surface of H9c2 cardiomyocytes, this method yields receptor numbers from 3.12 × 10(5) to 9.36 × 10(5) receptors/cell which are comparable with current methods. This can serve as a very good platform for rapid quantification of receptor numbers in ligand/drug binding and receptor characterization studies, which is an important part of pharmaceutical and biological research. PMID:25336403

  16. Two dimension (2-D) graphene-based nanomaterials as signal amplification elements in electrochemical microfluidic immune-devices: Recent advances.

    Science.gov (United States)

    Hasanzadeh, Mohammad; Shadjou, Nasrin; Mokhtarzadeh, Ahad; Ramezani, Mohammad

    2016-11-01

    Graphene is a 2-D carbon nanomaterial with many distinctive properties that are electrochemically beneficial, such as large surface-to-volume ratio, lowered power usage, high conductivity and electron mobility. Graphene-based electrochemical immune-devices have recently gained much importance for detecting antigens and biomarkers responsible for cancer diagnosis. This review describes fabrication and chemical modification of the surfaces of graphene for immunesensing applications. We also present a comprehensive overview of current developments and key issues in the determination of some biological molecules with particular emphasis on evaluating the models. This review focuses mostly on new developments in the last 5years in development of chip architecture and integration, different sensing modes that can be used in conjunction with microfluidics, and new applications that have emerged or have been demonstrated; it also aims to point out where future research can be directed to in these areas. PMID:27524045

  17. Rapid photochemical surface patterning of proteins in thiol-ene based microfluidic devices

    DEFF Research Database (Denmark)

    Lafleur, Josiane P.; Kwapiszewski, Radoslaw; Jensen, Thomas G.;

    2012-01-01

    The ability to immobilize biomolecules at specific locations on the surface of solid supports is central to many biochip applications. This paper reports the rapid one-step photochemical surface patterning of biomolecules in thiol-ene microfluidic chips. Adjusting the stoichiometric ratio of "thi...

  18. AlScN thin film based surface acoustic wave devices with enhanced microfluidic performance

    Science.gov (United States)

    Wang, W. B.; Fu, Y. Q.; Chen, J. J.; Xuan, W. P.; Chen, J. K.; Wang, X. Z.; Mayrhofer, P.; Duan, P. F.; Bittner, A.; Schmid, U.; Luo, J. K.

    2016-07-01

    This paper reports the characterization of scandium aluminum nitride (Al1-x Sc x N, x  =  27%) films and discusses surface acoustic wave (SAW) devices based on them. Both AlScN and AlN films were deposited on silicon by sputtering and possessed columnar microstructures with (0 0 0 2) crystal orientation. The AlScN/Si SAW devices showed improved electromechanical coupling coefficients (K 2, ~2%) compared with pure AlN films (hardness of the AlN film decreased significantly when Sc was doped, and this was responsible for the decreased acoustic velocity and resonant frequency, and the increased temperature coefficient of frequency, of the AlScN SAW devices.

  19. 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. PMID:26737632

  20. Application of membrane technology in microfluidic devices

    NARCIS (Netherlands)

    Jong, de Jorrit

    2008-01-01

    This thesis describes the application of membrane technology in microfluidic systems. The word ‘microfluidic’ refers to the research field that develops methods and devices to control, manipulate, and analyze flows in sub‐millimeter dimensions. General advantages of this miniaturization strategy inc

  1. A novel screen-printed microfluidic paper-based electrochemical device for detection of glucose and uric acid in urine.

    Science.gov (United States)

    Yao, Yong; Zhang, Chunsun

    2016-10-01

    A novel screen-printed microfluidic paper-based analytical device with all-carbon electrode-enabled electrochemical assay (SP-ACE-EC-μPAD) has been developed. The fabrication of these devices involved wax screen-printing, which was simple, low-cost and energy-efficient. The working, counter and reference electrodes were screen-printed using carbon ink on the patterned paper devices. Different wax screen-printing processes were examined and optimized, which led to an improved method with a shorter heating time (~5 s) and a lower heating temperature (75 °C). Different printing screens were examined, with a 300-mesh polyester screen yielding the highest quality wax screen-prints. The carbon electrodes were screen-printed on the μPADs and then examined using cyclic voltammetry. The analytical performance of the SP-ACE-EC-μPADs for the detection of glucose and uric acid in standard solutions was investigated. The results were reproducible, with a linear relationship [R(2) = 0.9987 (glucose) or 0.9997 (uric acid)] within the concentration range of interest, and with detection limits as low as 0.35 mM (glucose) and 0.08 mM (uric acid). To determine the clinical utility of the μPADs, chronoamperometry was used to analyze glucose and uric acid in real urine samples using the standard addition method. Our devices were able to detect the analytes of interest in complex real-world biological samples, and have the potential for use in a wide variety of applications. PMID:27628060

  2. Rapid and low-cost fabrication of polystyrene-based molds for PDMS microfluidic devices using a CO2 laser

    KAUST Repository

    Li, Huawei

    2011-11-01

    In this article, we described a rapid and low-cost method to fabricate polystyrene molds for PDMS microfluidic devices using a CO2 laser system. It takes only several minutes to fabricate the polystyrene mold with bump pattern on top of it using a CO2 laser system. The bump pattern can be easily transferred to PDMS and fabricate microchannles as deep as 3μm on PDMS. © (2012) Trans Tech Publications, Switzerland.

  3. 3D origami-based multifunction-integrated immunodevice: low-cost and multiplexed sandwich chemiluminescence immunoassay on microfluidic paper-based analytical device.

    Science.gov (United States)

    Ge, Lei; Wang, Shoumei; Song, Xianrang; Ge, Shenguang; Yu, Jinghua

    2012-09-01

    A novel 3D microfluidic paper-based immunodevice, integrated with blood plasma separation from whole blood samples, automation of rinse steps, and multiplexed CL detections, was developed for the first time based on the principle of origami (denoted as origami-based device). This 3D origami-based device, comprised of one test pad surrounded by four folding tabs, could be patterned and fabricated by wax-printing on paper in bulk. In this work, a sandwich-type chemiluminescence (CL) immunoassay was introduced into this 3D origami-based immunodevice, which could separate the operational procedures into several steps including (i) folding pads above/below and (ii) addition of reagent/buffer under a specific sequence. The CL behavior, blood plasma separation, washing protocol, and incubation time were investigated in this work. The developed 3D origami-based CL immunodevice, combined with a typical luminuol-H(2)O(2) CL system and catalyzed by Ag nanoparticles, showed excellent analytical performance for the simultaneous detection of four tumor markers. The whole blood samples were assayed and the results obtained were in agreement with the reference values from the parallel single-analyte test. This paper-based microfluidic origami CL detection system provides a new strategy for a low-cost, sensitive, simultaneous multiplex immunoassay and point-of-care diagnostics. PMID:22763468

  4. A diffusion based long-range and steady chemical gradient generator on a microfluidic device for studying bacterial chemotaxis

    Science.gov (United States)

    Murugesan, Nithya; Singha, Siddhartha; Panda, Tapobrata; Das, Sarit K.

    2016-03-01

    Studies on chemotaxis in microfluidics device have become a major area of research to generate physiologically similar environment in vitro. In this work, a novel micro-fluidic device has been developed to study chemo-taxis of cells in near physiological condition which can create controllable, steady and long-range chemical gradients using various chemo-effectors in a micro-channel. Hydrogels like agarose, collagen, etc, can be used in the device to maintain exclusive diffusive flux of various chemical species into the micro-channel under study. Variations of concentrations and flow rates of Texas Red dextran in the device revealed that an increase in the concentration of the dye in the feed from 6 to 18 μg ml-1, causes a steeper chemical gradient in the device, whereas the flow rate of the dye has practically no effect on the chemical gradient in the device. This observation confirms that a diffusion controlled chemical gradient is generated in the micro-channel. Chemo-taxis of E. coli cells were studied under the steady gradient of a chemo-attractant and a chemo-repellent separately in the same chemical gradient generator. For sorbitol and NiSO4·6H2O, the bacterial cells exhibit a steady distribution in the micro channel after 1 h and 30 min, respectively. From the distribution of bacterial population chemo-tactic strength of the chemo-effectors was estimated for E. coli. In a long microfluidic channel, migration behavior of bacterial cells under diffusion controlled chemical gradient showed chemotaxis, random movement, aggregation, and concentration dependent reverse chemotaxis.

  5. A two-compartment microfluidic device for long-term live cell detection based on surface plasmon resonance.

    Science.gov (United States)

    Deng, Shijie; Yu, Xinglong; Liu, Ran; Chen, Weixing; Wang, Peng

    2016-07-01

    A two-compartment microfluidic device integrated with a surface plasmon resonance (SPR) interferometric imaging system has been developed for long-term and real-time cell detection. The device uses a porous membrane sandwiched between two chambers to obtain an exact medium exchange rate and minimal fluid shear stress for cell culture. The two-compartment device was optimized by COMSOL simulations and fabricated using Poly (dimethylsiloxane) elastomer replica molding methods. To confirm the capability of the microfluidic device to maintain the cell physiological environment over long intervals, HeLa cells were cultured in the device for up to 48 h. The cell proliferation process was monitored by both SPR and microscopic time-lapse imaging. The SPR response showed four phases with different growth rates, and agreed well with the time-lapse imaging. Furthermore, real-time detection of cell behaviors under different doses of Paclitaxel and Cisplatin was performed. The SPR responses revealed dose-dependent inhibitions of cell proliferation, with distinct drug action kinetics. PMID:27570574

  6. Distance-Based Tear Lactoferrin Assay on Microfluidic Paper Device Using Interfacial Interactions on Surface-Modified Cellulose.

    Science.gov (United States)

    Yamada, Kentaro; Henares, Terence G; Suzuki, Koji; Citterio, Daniel

    2015-11-11

    "Distance-based" detection motifs on microfluidic paper-based analytical devices (μPADs) allow quantitative analysis without using signal readout instruments in a similar manner to classical analogue thermometers. To realize a cost-effective and calibration-free distance-based assay of lactoferrin in human tear fluid on a μPAD not relying on antibodies or enzymes, we investigated the fluidic mobilities of the target protein and Tb(3+) cations used as the fluorescent detection reagent on surface-modified cellulosic filter papers. Chromatographic elution experiments in a tear-like sample matrix containing electrolytes and proteins revealed a collapse of attractive electrostatic interactions between lactoferrin or Tb(3+) and the cellulosic substrate, which was overcome by the modification of the paper surface with the sulfated polysaccharide ι-carrageenan. The resulting μPAD based on the fluorescence emission distance successfully analyzed 0-4 mg mL(-1) of lactoferrin in complex human tear matrix with a lower limit of detection of 0.1 mg mL(-1) by simple visual inspection. Assay results of 18 human tear samples including ocular disease patients and healthy volunteers showed good correlation to the reference ELISA method with a slope of 0.997 and a regression coefficient of 0.948. The distance-based quantitative signal and the good batch-to-batch fabrication reproducibility relying on printing methods enable quantitative analysis by simply reading out "concentration scale marks" printed on the μPAD without performing any calibration and using any signal readout instrument.

  7. Fluid control structures in microfluidic devices

    Science.gov (United States)

    Mathies, Richard A.; Grover, William H.; Skelley, Alison; Lagally, Eric; Liu, Chung N.

    2008-11-04

    Methods and apparatus for implementing microfluidic analysis devices are provided. A monolithic elastomer membrane associated with an integrated pneumatic manifold allows the placement and actuation of a variety of fluid control structures, such as structures for pumping, isolating, mixing, routing, merging, splitting, preparing, and storing volumes of fluid. The fluid control structures can be used to implement a variety of sample introduction, preparation, processing, and storage techniques.

  8. Fluid control structures in microfluidic devices

    Science.gov (United States)

    Mathies, Richard A. (Inventor); Grover, William H. (Inventor); Skelley, Alison (Inventor); Lagally, Eric (Inventor); Liu, Chung N. (Inventor)

    2008-01-01

    Methods and apparatus for implementing microfluidic analysis devices are provided. A monolithic elastomer membrane associated with an integrated pneumatic manifold allows the placement and actuation of a variety of fluid control structures, such as structures for pumping, isolating, mixing, routing, merging, splitting, preparing, and storing volumes of fluid. The fluid control structures can be used to implement a variety of sample introduction, preparation, processing, and storage techniques.

  9. Microwave Induced Ethanol Bath Bonding for PMMA Microfluidic Device

    Institute of Scientific and Technical Information of China (English)

    Cuicui Zhuang

    2016-01-01

    High bonding strength, low deformation and convenient procedure are all very important aspects in the microfluidic device fabrication process. In this paper, an improved microwave induced bonding technology is proposed to fabricate microfluidic device based on methyl methacrylate (PMMA). This method employs pure ethanol as the bonding assisted solvent. The ethanol not only acts as the microwave absorbing material, but also works as the organic solvent in bath. The presented research work has shown that the bonding process can be completed in less than 45 s. Furthermore, the convenient bonding only applies microwave oven, beakers and binder clips. Then, we discuss effects of microwave power, bonding time on bonding strength and deformation of microstructures on PMMA microfluidic device. Finally, a 4 layers micro⁃mixer has been fabricated using the proposed bonding technique which includes 15 trapezoid micro⁃channels, 9 T⁃type mix units and an X⁃type mix unit. Experimental results show that the proposed bonding method have some advantages compared with several traditional bonding technologies, such as hot pressing bonding, ultrasonic bonding and solvent assisted bonding methods in respect of bonding strength, deformation and bonding process. The presented work would be helpful for low coat mass production of multilayer polymer microfluidic devices in lab.

  10. Silicon microfluidic flow focusing devices for the production of size-controlled PLGA based drug loaded microparticles.

    Science.gov (United States)

    Keohane, Kieran; Brennan, Des; Galvin, Paul; Griffin, Brendan T

    2014-06-01

    The increasing realisation of the impact of size and surface properties on the bio-distribution of drug loaded colloidal particles has driven the application of micro fabrication technologies for the precise engineering of drug loaded microparticles. This paper demonstrates an alternative approach for producing size controlled drug loaded PLGA based microparticles using silicon Microfluidic Flow Focusing Devices (MFFDs). Based on the precise geometry and dimensions of the flow focusing channel, microparticle size was successfully optimised by modifying the polymer type, disperse phase (Qd) flow rate, and continuous phase (Qc) flow rate. The microparticles produced ranged in sizes from 5 to 50 μm and were highly monodisperse (coefficient of variation <5%). A comparison of Ciclosporin (CsA) loaded PLGA microparticles produced by MFFDs vs conventional production techniques was also performed. MFFDs produced microparticles with a narrower size distribution profile, relative to the conventional approaches. In-vitro release kinetics of CsA was found to be influenced by the production technique, with the MFFD approach demonstrating the slowest rate of release over 7 days (4.99 ± 0.26%). Finally, MFFDs were utilised to produce pegylated microparticles using the block co-polymer, PEG-PLGA. In contrast to the smooth microparticles produced using PLGA, PEG-PLGA microparticles displayed a highly porous surface morphology and rapid CsA release, with 85 ± 6.68% CsA released after 24h. The findings from this study demonstrate the utility of silicon MFFDs for the precise control of size and surface morphology of PLGA based microparticles with potential drug delivery applications.

  11. MEMS monocrystalline-silicon based thermal devices for chemical and microfluidic applications

    NARCIS (Netherlands)

    Mihailovic, M.

    2011-01-01

    This thesis explores the employment of monocrystalline silicon in microsystems as an active material for different thermal functions, such as heat generation and heat transfer by conduction. In chapter 1 applications that need thermal micro devices, micro heaters and micro heat exchangers, are brief

  12. Microfluidic device fabrication by thermoplastic hot-embossing.

    Science.gov (United States)

    Yang, Shuang; Devoe, Don L

    2013-01-01

    Due to their low cost compatibility with replication-based fabrication methods, thermoplastics represent an exceptionally attractive family of materials for the fabrication of lab-on-a-chip platforms. A diverse range of thermoplastic materials suitable for microfluidic fabrication is available, offering a wide selection of mechanical and chemical properties that can be leveraged and further tailored for specific applications. While high-throughput embossing methods such as reel-to-reel processing of thermoplastics is an attractive method for industrial microfluidic chip production, the use of single chip hot embossing is a cost-effective technique for realizing high-quality microfluidic devices during the prototyping stage. Here we describe methods for the replication of microscale features in two thermoplastics, polymethylmethacrylate (PMMA) and polycarbonate (PC), using hot embossing from a silicon template fabricated by deep reactive-ion etching.

  13. Microfluidic device for unidirectional axon growth

    Science.gov (United States)

    Malishev, E.; Pimashkin, A.; Gladkov, A.; Pigareva, Y.; Bukatin, A.; Kazantsev, V.; Mukhina, I.; Dubina, M.

    2015-11-01

    In order to better understand the communication and connectivity development of neuron networks, we designed microfluidic devices with several chambers for growing dissociated neuronal cultures from mice fetal hippocampus (E18). The chambers were connected with microchannels providing unidirectional axonal growth between “Source” and “Target” neural sub-networks. Experiments were performed in a hippocampal cultures plated in a poly-dimethylsiloxane (PDMS) microfluidic chip, aligned with a 60 microelectrode array (MEA). Axonal growth through microchannels was observed with brightfield, phase-contrast and fluorescence microscopy, and after 7 days in vitro electrical activity was recorded. Visual inspection and spike propagation analysis showed the predominant axonal growth in microchannels in a direction from “Source” to “Target”.

  14. High content screening in microfluidic devices

    Science.gov (United States)

    Cheong, Raymond; Paliwal, Saurabh; Levchenko, Andre

    2011-01-01

    Importance of the field Miniaturization is key to advancing the state-of-the-art in high content screening (HCS), in order to enable dramatic cost savings through reduced usage of expensive biochemical reagents and to enable large-scale screening on primary cells. Microfluidic technology offers the potential to enable HCS to be performed with an unprecedented degree of miniaturization. Areas covered in this review This perspective highlights a real-world example from the authors’ work of HCS assays implemented in a highly miniaturized microfluidic format. Advantages of this technology are discussed, including cost savings, high throughput screening on primary cells, improved accuracy, the ability to study complex time-varying stimuli, and ease of automation, integration, and scaling. What the reader will gain The reader will understand the capabilities of a new microfluidics-based platform for HCS, and the advantages it provides over conventional plate-based HCS. Take home message Microfluidics technology will drive significant advancements and broader usage and applicability of HCS in drug discovery. PMID:21852997

  15. One-step fabrication of 3D silver paste electrodes into microfluidic devices for enhanced droplet-based cell sorting

    Directory of Open Access Journals (Sweden)

    Lang Rao

    2015-05-01

    Full Text Available 3D microelectrodes are one-step fabricated into a microfluidic droplet separator by filling conductive silver paste into PDMS microchambers. The advantages of 3D silver paste electrodes in promoting droplet sorting accuracy are systematically demonstrated by theoretical calculation, numerical simulation and experimental validation. The employment of 3D electrodes also helps to decrease the droplet sorting voltage, guaranteeing that cells encapsulated in droplets undergo chip-based sorting processes are at better metabolic status for further potential cellular assays. At last, target droplet containing single cell are selectively sorted out from others by an appropriate electric pulse. This method provides a simple and inexpensive alternative to fabricate 3D electrodes, and it is expected our 3D electrode-integrated microfluidic droplet separator platform can be widely used in single cell operation and analysis.

  16. Three-dimensional paper microfluidic devices assembled using the principles of origami.

    Science.gov (United States)

    Liu, Hong; Crooks, Richard M

    2011-11-01

    We report a method, based on the principles of origami (paper folding), for fabricating three-dimensional (3-D) paper microfluidic devices. The entire 3-D device is fabricated on a single sheet of flat paper in a single photolithographic step. It is assembled by simply folding the paper by hand. Following analysis, the device can be unfolded to reveal each layer. The applicability of the device to chemical analysis is demonstrated by colorimetric and fluorescence assays using multilayer microfluidic networks.

  17. Fluorescent zinc and copper complexes for detection of adrafinil in paper-based microfluidic devices.

    Science.gov (United States)

    Caglayan, Mehmet Gokhan; Sheykhi, Sara; Mosca, Lorenzo; Anzenbacher, Pavel

    2016-07-01

    Recognition of electroneutral Lewis bases and anions in aqueous media is extremely difficult. We show that fluorescent coordinatively unsaturated metal complexes can recognize various Lewis bases while providing an easy-to-detect fluorescence response. This approach is applied to the detection of adrafinil, a banned performance-enhancing drug. PMID:27293080

  18. 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.

  19. Simple and cheap microfluidic devices for the preparation of monodisperse emulsions.

    Science.gov (United States)

    Deng, Nan-Nan; Meng, Zhi-Jun; Xie, Rui; Ju, Xiao-Jie; Mou, Chuan-Lin; Wang, Wei; Chu, Liang-Ying

    2011-12-01

    Droplet microfluidics, which can generate monodisperse droplets or bubbles in unlimited numbers, at high speed and with complex structures, have been extensively investigated in chemical and biological fields. However, most current methods for fabricating microfluidic devices, such as glass etching, soft lithography in polydimethylsiloxane (PDMS) or assembly of glass capillaries, are usually either expensive or complicated. Here we report the fabrication of simple and cheap microfluidic devices based on patterned coverslips and microscope glass slides. The advantages of our approach for fabricating microfluidic devices lie in a simple process, inexpensive processing equipment and economical laboratory supplies. The fabricated microfluidic devices feature a flexible design of microchannels, easy spatial patterning of surface wettability, and good chemical compatibility and optical properties. We demonstrate their utilities for generation of monodisperse single and double emulsions with highly controllable flexibility. PMID:22025190

  20. Microwave Dielectric Heating of Drops in Microfluidic Devices

    CERN Document Server

    Issadore, David; Brown, Keith A; Sandberg, Lori; Weitz, David; Westervelt, Robert M

    2009-01-01

    We present a technique to locally and rapidly heat water drops in microfluidic devices with microwave dielectric heating. Water absorbs microwave power more efficiently than polymers, glass, and oils due to its permanent molecular dipole moment that has a large dielectric loss at GHz frequencies. The relevant heat capacity of the system is a single thermally isolated picoliter drop of water and this enables very fast thermal cycling. We demonstrate microwave dielectric heating in a microfluidic device that integrates a flow-focusing drop maker, drop splitters, and metal electrodes to locally deliver microwave power from an inexpensive, commercially available 3.0 GHz source and amplifier. The temperature of the drops is measured by observing the temperature dependent fluorescence intensity of cadmium selenide nanocrystals suspended in the water drops. We demonstrate characteristic heating times as short as 15 ms to steady-state temperatures as large as 30 degrees C above the base temperature of the microfluidi...

  1. Spiral-based microfluidic device for long-term time course imaging of Neurospora crassa with single nucleus resolution.

    Science.gov (United States)

    Lee, Kang Kug; Labiscsak, Laszlo; Ahn, Chong H; Hong, Christian I

    2016-09-01

    Real-time imaging of fluorescent reporters plays a critical role in elucidating fundamental molecular mechanisms including circadian rhythms in the model filamentous fungus, Neurospora crassa. However, monitoring N. crassa for an extended period of time with single nucleus resolution is a technically challenging task due to hyphal growth that rapidly moves beyond a region of interest during microscopy experiments. In this report, we have proposed a two-dimensional spiral-based microfluidic platform and applied for monitoring the single-nucleus dynamics in N. crassa for long-term time course experiments. PMID:27345439

  2. Simple and inexpensive microfluidic devices for the generation of monodisperse multiple emulsions

    KAUST Repository

    Li, Erqiang

    2013-12-16

    Droplet-based microfluidic devices have become a preferred versatile platform for various fields in physics, chemistry and biology. Polydimethylsiloxane soft lithography, the mainstay for fabricating microfluidic devices, usually requires the usage of expensive apparatus and a complex manufacturing procedure. Here, we report the design and fabrication of simple and inexpensive microfluidic devices based on microscope glass slides and pulled glass capillaries, for generating monodisperse multiple emulsions. The advantages of our method lie in a simple manufacturing procedure, inexpensive processing equipment and flexibility in the surface modification of the designed microfluidic devices. Different types of devices have been designed and tested and the experimental results demonstrated their robustness for preparing monodisperse single, double, triple and multi-component emulsions. © 2014 IOP Publishing Ltd.

  3. Recent microfluidic devices for studying gamete and embryo biomechanics.

    Science.gov (United States)

    Lai, David; Takayama, Shuichi; Smith, Gary D

    2015-06-25

    The technical challenges of biomechanic research such as single cell analysis at a high monetary cost, labor, and time for just a small number of measurements is a good match to the strengths of microfluidic devices. New scientific discoveries in the fertilization and embryo development process, of which biomechanics is a major subset of interest, is crucial to fuel the continual improvement of clinical practice in assisted reproduction. The following review will highlight some recent microfluidic devices tailored for gamete and embryo biomechanics where biomimicry arises as a major theme of microfluidic device design and function, and the application of fundamental biomechanic principles are used to improve outcomes of cryopreservation. PMID:25801423

  4. Microfluidics and Lab-on-a-Chip Devices

    DEFF Research Database (Denmark)

    Castillo, Jaime

    2015-01-01

    TAS technologies need to join forces with those behind the new communication devices which provide sources of power, detection and data transmission complementing the features that lab-on-a-chip and microTAS platforms can offer. An increasing number of microfluidic-based devices, developed both in small start......The rapid advances in microfabrication and nanofabrication in combination with the synthesis and discovery of new materials have propelled the drive to develop new technological devices such as smartphones, personal and tablet computers. These devices have changed the way humankind interacts...... and communicates and this change occurred very quickly due in part to decreased production and commercialization costs. As a result, not only nations with powerful economies but also emerging economies and poor countries can get access to these technologies and experience new ways to interact and instantly...

  5. Characterisation of an Adhesive-free Packaging System for Polymeric Microfluidic Biochemical Devices and Reactors

    OpenAIRE

    Reichen, M.; Super, A.; Davies, M J; Macown, R. J.; O'Sullivan, B; Kirk, T. V.; Marques, M. P. C.; Dimov, N.; Szita, N

    2014-01-01

    The development of microfluidic devices is an iterative process that involves series of improvements, which can be costly and time consuming. We present a packaging system which makes use of an accessible rapid prototyping method, and facilitates the rapid and reliable implementation of polymeric microfluidic device designs. The packaging system uses a modular design and is based on an adhesive-free connection of a reusable and stiff polymeric interface plate with a disposable, soft microflui...

  6. Fabrication of gravity-driven microfluidic device

    Science.gov (United States)

    Yamada, H.; Yoshida, Y.; Terada, N.; Hagihara, S.; Komatsu, T.; Terasawa, A.

    2008-12-01

    We have studied the micro total analysis system as a blood test. A microfluidic device with a three-pronged microchannel and artificial capillary vessels was fabricated. The microchannel is to transport blood, focus blood cells, and line them up. The vessels are to observe red blood cell deformation. An excimer laser was used to form grooves and so on. Numbers of thermosetting resin film and fluororesin were piled up on a cover glass. A laser fabricated part of the channel at the each film every lamination, and then a three-dimensional structure microchannel was fabricated. The channel sizes have widths of 50-150 μm and depths of 45 μm. Through holes used as artificial capillary vessels are made in the fluororesin having a minimum diameter of 5 μm and a length of 100 μm. As blood and a physiological saline are injected into the microchannel, the device stands upward facing the channel, and blood cells go into the vessels by the force of gravity and sheath flow of the saline. By gravity various groove patterns were made changing the width and length for measurement of blood focusing. Moreover, the red blood cell deformation was observed in the vessels with a microscope.

  7. Thermal loading in flow-through electroporation microfluidic devices.

    Science.gov (United States)

    del Rosal, Blanca; Sun, Chen; Loufakis, Despina Nelie; Lu, Chang; Jaque, Daniel

    2013-08-01

    Thermal loading effects in flow-through electroporation microfluidic devices have been systematically investigated by using dye-based ratiometric luminescence thermometry. Fluorescence measurements have revealed the crucial role played by both the applied electric field and flow rate on the induced temperature increments at the electroporation sections of the devices. It has been found that Joule heating could raise the intra-channel temperature up to cytotoxic levels (>45 °C) only when conditions of low flow rates and high applied voltages are applied. Nevertheless, when flow rates and electric fields are set to those used in real electroporation experiments we have found that local heating is not larger than a few degrees, i.e. temperature is kept within the safe range (electroporation devices from which the heat affected area can be elucidated. Experimental data have been found to be in excellent agreement with numerical simulations that have also revealed the presence of a non-homogeneous temperature distribution along the electroporation channel whose magnitude is critically dependent on both applied electric field and flow rate. Results included in this work will allow for full control over the electroporation conditions in flow-through microfluidic devices.

  8. Integration of Capacitive Micromachined Ultrasound Transducers to Microfluidic Devices

    KAUST Repository

    Viržonis, Darius

    2013-10-22

    The design and manufacturing flexibility of capacitive micromachined ultrasound transducers (CMUT) makes them attractive option for integration with microfluidic devices both for sensing and fluid manipulation. CMUT concept is introduced here by presentin

  9. Ionic current devices-Recent progress in the merging of electronic, microfluidic, and biomimetic structures.

    Science.gov (United States)

    Koo, Hyung-Jun; Velev, Orlin D

    2013-01-01

    We review the recent progress in the emerging area of devices and circuits operating on the basis of ionic currents. These devices operate at the intersection of electrochemistry, electronics, and microfluidics, and their potential applications are inspired by essential biological processes such as neural transmission. Ionic current rectification has been demonstrated in diode-like devices containing electrolyte solutions, hydrogel, or hydrated nanofilms. More complex functions have been realized in ionic current based transistors, solar cells, and switching memory devices. Microfluidic channels and networks-an intrinsic component of the ionic devices-could play the role of wires and circuits in conventional electronics. PMID:24404020

  10. Ionic current devices-Recent progress in the merging of electronic, microfluidic, and biomimetic structures.

    Science.gov (United States)

    Koo, Hyung-Jun; Velev, Orlin D

    2013-05-09

    We review the recent progress in the emerging area of devices and circuits operating on the basis of ionic currents. These devices operate at the intersection of electrochemistry, electronics, and microfluidics, and their potential applications are inspired by essential biological processes such as neural transmission. Ionic current rectification has been demonstrated in diode-like devices containing electrolyte solutions, hydrogel, or hydrated nanofilms. More complex functions have been realized in ionic current based transistors, solar cells, and switching memory devices. Microfluidic channels and networks-an intrinsic component of the ionic devices-could play the role of wires and circuits in conventional electronics.

  11. A Microfluidic Device for Spatiotemporal Delivery of Stimuli to Cells

    Directory of Open Access Journals (Sweden)

    Zubaidah Ningsih

    2015-03-01

    Full Text Available Living cells encounter many stimuli from the immediate environment. Receptors recognize these environmental cues and transduce signals to produce cell responses. The frequency of a signal is now emerging as an important factor determining cell responses. As a componentry system in understanding temporal stimulation, microfluidic devices allow the observation of cell behaviour under dynamic stimulation and controllable environment. In this paper we describe the design, construction and characterization of a microfluidic device suitable for cell stimulation studies.

  12. Solvent-resistant elastomeric microfluidic devices and applications

    Science.gov (United States)

    van Dam, Robert Michael

    Microfluidics is increasingly being used in many areas of biotechnology and chemistry to achieve reduced reagent volumes, improved performance, integration, and parallelism, among other advantages. Though early devices were based on rigid materials such as glass and silicon, elastomeric materials such as polydiznethylsiloxane (PDMS) are rapidly emerging as a ubiquitous platform for applications in biotechnology. This is due, in part, to simpler fabrication procedures and to the ability to integrate mechanical microvalves at vastly greater densities. For many applications in the areas of chemical synthesis and analysis, however, PDMS cannot replace glass and silicon due to its incompatibility with many solvents and reagents. Such areas could benefit tremendously from the development of an elastomeric microfluidic device technology that combines the advantages of PDMS with the property of solvent resistance. Simplified fabrication could increase the accessibility of microfluidics, and the possibility of dense valve integration could lead to significant advances in device sophistication. Applications could be more rapidly developed by design re-use due to the independence of mechanical valves on fluid properties (unlike electrokinetic pumping), and the property of permeability could enable novel fluidic functions for accessing a broader range of reactions than is possible in glass and silicon. The first half of this thesis describes our strategies and efforts to develop this new enabling technology. Several approaches are presented in Chapter 3, and two particularly successful ones, based on new elastomers (FNB and PFPE), are described in Chapters 4 and 5. Chapter 6 describes a novel method of fabricating devices from 3D molds that could expand the range of useful clastomers. The second half of this thesis discusses microfluidic combinatorial synthesis and high throughput screening-applications that take particular advantage of the ability to integrate thousands of

  13. 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.

  14. A new UV-curing elastomeric substrate for rapid prototyping of microfluidic devices

    Science.gov (United States)

    Alvankarian, Jafar; Yeop Majlis, Burhanuddin

    2012-03-01

    Rapid prototyping in the design cycle of new microfluidic devices is very important for shortening time-to-market. Researchers are facing the challenge to explore new and suitable substrates with simple and efficient microfabrication techniques. In this paper, we introduce and characterize a UV-curing elastomeric polyurethane methacrylate (PUMA) for rapid prototyping of microfluidic devices. The swelling and solubility of PUMA in different chemicals is determined. Time-dependent measurements of water contact angle show that the native PUMA is hydrophilic without surface treatment. The current monitoring method is used for measurement of the electroosmotic flow mobility in the microchannels made from PUMA. The optical, physical, thermal and mechanical properties of PUMA are evaluated. The UV-lithography and molding process is used for making micropillars and deep channel microfluidic structures integrated to the supporting base layer. Spin coating is characterized for producing different layer thicknesses of PUMA resin. A device is fabricated and tested for examining the strength of different bonding techniques such as conformal, corona treating and semi-curing of two PUMA layers in microfluidic application and the results show that the bonding strengths are comparable to that of PDMS. We also report fabrication and testing of a three-layer multi inlet/outlet microfluidic device including a very effective fluidic interconnect for application demonstration of PUMA as a promising new substrate. A simple micro-device is developed and employed for observing the pressure deflection of membrane made from PUMA as a very effective elastomeric valve in microfluidic devices.

  15. Droplet Microfluidics for Chip-Based Diagnostics

    Directory of Open Access Journals (Sweden)

    Karan V. I. S. Kaler

    2014-12-01

    Full Text Available Droplet microfluidics (DMF is a fluidic handling technology that enables precision control over dispensing and subsequent manipulation of droplets in the volume range of microliters to picoliters, on a micro-fabricated device. There are several different droplet actuation methods, all of which can generate external stimuli, to either actively or passively control the shape and positioning of fluidic droplets over patterned substrates. In this review article, we focus on the operation and utility of electro-actuation-based DMF devices, which utilize one or more micro-/nano-patterned substrates to facilitate electric field-based handling of chemical and/or biological samples. The underlying theory of DMF actuations, device fabrication methods and integration of optical and opto-electronic detectors is discussed in this review. Example applications of such electro-actuation-based DMF devices have also been included, illustrating the various actuation methods and their utility in conducting chip-based laboratory and clinical diagnostic assays.

  16. 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.

  17. 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.

  18. An easy-to-use microfluidic interconnection system to create quick and reversibly interfaced simple microfluidic devices

    Science.gov (United States)

    Pfreundt, Andrea; Brandt Andersen, Karsten; Dimaki, Maria; Svendsen, Winnie E.

    2015-11-01

    The presented microfluidic interconnection system provides an alternative for the individual interfacing of simple microfluidic devices fabricated in polymers such as polymethylmethacrylate, polycarbonate and cyclic olefin polymer. A modification of the device inlet enables the direct attachment of tubing (such as polytetrafluoroethylene tubing) secured and sealed by using a small plug, without the need for additional assembly, glue or o-rings. This provides a very clean connection that does not require additional, potentially incompatible, materials. The tightly sealed connection can withstand pressures above 250 psi and therefore supports applications with high flow rates or highly viscous fluids. The ease of incorporation, configuration, fabrication and use make this interconnection system ideal for the rapid prototyping of simple microfluidic devices or other integrated systems that require microfluidic interfaces. It provides a valuable addition to the toolbox of individual and small arrays of connectors suitable for micromachined or template-based injection molded devices since it does not require protruding, threaded or glued modifications on the inlet and avoids bulky and expensive fittings.

  19. Wearable tactile sensor based on flexible microfluidics.

    Science.gov (United States)

    Yeo, Joo Chuan; Yu, Jiahao; Koh, Zhao Ming; Wang, Zhiping; Lim, Chwee Teck

    2016-08-16

    In this work, we develop a liquid-based thin film microfluidic tactile sensor of high flexibility, robustness and sensitivity. The microfluidic elastomeric structure comprises a pressure sensitive region and parallel arcs that interface with screen-printed electrodes. The microfluidic sensor is functionalized with a highly conductive metallic liquid, eutectic gallium indium (eGaIn). Microdeformation on the pressure sensor results in fluid displacement which corresponds to a change in electrical resistance. By emulating parallel electrical circuitry in our microchannel design, we reduced the overall electrical resistance of the sensor, therefore enhancing its device sensitivity. Correspondingly, we report a device workable within a range of 4 to 100 kPa and sensitivity of up to 0.05 kPa(-1). We further demonstrate its robustness in withstanding >2500 repeated loading and unloading cycles. Finally, as a proof of concept, we demonstrate that the sensors may be multiplexed to detect forces at multiple regions of the hand. In particular, our sensors registered unique electronic signatures in object grasping, which could provide better assessment of finger dexterity. PMID:27438370

  20. Wearable tactile sensor based on flexible microfluidics.

    Science.gov (United States)

    Yeo, Joo Chuan; Yu, Jiahao; Koh, Zhao Ming; Wang, Zhiping; Lim, Chwee Teck

    2016-08-16

    In this work, we develop a liquid-based thin film microfluidic tactile sensor of high flexibility, robustness and sensitivity. The microfluidic elastomeric structure comprises a pressure sensitive region and parallel arcs that interface with screen-printed electrodes. The microfluidic sensor is functionalized with a highly conductive metallic liquid, eutectic gallium indium (eGaIn). Microdeformation on the pressure sensor results in fluid displacement which corresponds to a change in electrical resistance. By emulating parallel electrical circuitry in our microchannel design, we reduced the overall electrical resistance of the sensor, therefore enhancing its device sensitivity. Correspondingly, we report a device workable within a range of 4 to 100 kPa and sensitivity of up to 0.05 kPa(-1). We further demonstrate its robustness in withstanding >2500 repeated loading and unloading cycles. Finally, as a proof of concept, we demonstrate that the sensors may be multiplexed to detect forces at multiple regions of the hand. In particular, our sensors registered unique electronic signatures in object grasping, which could provide better assessment of finger dexterity.

  1. Electroporation of cells in microfluidic devices: a review

    NARCIS (Netherlands)

    Fox, M.B.; Esveld, D.C.; Valero, A.; Luttge, R.; Mastwijk, H.C.; Bartels, P.V.; Berg, van den A.; Boom, R.M.

    2006-01-01

    In recent years, several publications on microfluidic devices have focused on the process of electroporation, which results in the poration of the biological cell membrane. The devices involved are designed for cell analysis, transfection or pasteurization. The high electric field strengths needed a

  2. Direct digital manufacturing of autonomous centrifugal microfluidic device

    Science.gov (United States)

    Ukita, Yoshiaki; Takamura, Yuzuru; Utsumi, Yuichi

    2016-06-01

    This paper presents strategies that attempt to solve two key problems facing the commercialization of microfluidics: cost reduction in microfluidic chip manufacturing and microfluidic device driver development. To reduce the cost of microfluidic chip manufacturing, we propose to use of three-dimensional (3D) printers for direct digital manufacturing (DDM). An evaluation of 3D micro-scale structure printing using several 3D printers is reported, and some of the technical issues to be addressed in the future are suggested. To evaluate micro-scale printing, three types of 3D printers, with the ability to print structures on the scale of several hundred meters, were selected by first screening six 3D printers. Line and space patterns with line widths of 100-500 µm and an aspect ratio of one were printed and evaluated. The estimated critical dimension was around 200 µm. The manufacturing of a monolithic microfluidic chip with embedded channels was also demonstrated. Monolithic microfluidic chips with embedded microchannels having 500 × 500 and 250 × 250 µm2 cross sections and 2-20 mm lengths were printed, and the fidelity of the channel shape, residual supporting material, and flow of liquid water were evaluated. The liquid flow evaluation showed that liquid water could flow through all of the microchannels with the 500 × 500 µm2 cross section, whereas this was not possible through some of the channels with the 250 × 250 µm2 cross section because of the residual resin or supporting material. To reduce the device-driver cost, we propose to use of the centrifugal microfluidic concept. An autonomous microfluidic device that could implement sequential flow control under a steadily rotating condition was printed. Four-step flow injection under a steadily rotating condition at 1500 rpm was successfully demonstrated without any external triggering such as changing the rotational speed.

  3. Droplets and Bubbles in Microfluidic Devices

    Science.gov (United States)

    Anna, Shelley Lynn

    2016-01-01

    Precise, tunable emulsions and foams produced in microfluidic geometries have found wide application in biochemical analysis and materials synthesis and characterization. Superb control of the volume, uniformity, and generation rate of droplets and bubbles arises from unique features of the microscale behavior of fluid interfaces. Fluid interfaces confined within microfluidic channels behave quite differently than their counterparts in unbounded flows. Confinement inhibits capillary instabilities so that breakup occurs by largely quasi-static mechanisms. The three-dimensional flow near confined interfaces in rectangular geometries and feedback effects from resistance changes in the entire microfluidic network play important roles in regulating the interfacial deformation. Timescales for transport of surfactants and particles to interfaces compete with flow timescales at the microscale, providing further opportunity for tuning the interfacial coverage and properties of individual droplets and bubbles.

  4. An easy-to-use microfluidic interconnection system to create quick and reversibly interfaced simple microfluidic devices

    DEFF Research Database (Denmark)

    Pfreundt, Andrea; Andersen, Karsten Brandt; Dimaki, Maria;

    2015-01-01

    The presented microfluidic interconnection system provides an alternative for the individual interfacing of simple microfluidic devices fabricated in polymers such as polymethylmethacrylate, polycarbonate and cyclic olefin polymer. A modification of the device inlet enables the direct attachment...... pressures above 250 psi and therefore supports applications with high flow rates or highly viscous fluids. The ease of incorporation, configuration, fabrication and use make this interconnection system ideal for the rapid prototyping of simple microfluidic devices or other integrated systems that require...

  5. 3D printed microfluidic devices: enablers and barriers.

    Science.gov (United States)

    Waheed, Sidra; Cabot, Joan M; Macdonald, Niall P; Lewis, Trevor; Guijt, Rosanne M; Paull, Brett; Breadmore, Michael C

    2016-05-24

    3D printing has the potential to significantly change the field of microfluidics. The ability to fabricate a complete microfluidic device in a single step from a computer model has obvious attractions, but it is the ability to create truly three dimensional structures that will provide new microfluidic capability that is challenging, if not impossible to make with existing approaches. This critical review covers the current state of 3D printing for microfluidics, focusing on the four most frequently used printing approaches: inkjet (i3DP), stereolithography (SLA), two photon polymerisation (2PP) and extrusion printing (focusing on fused deposition modeling). It discusses current achievements and limitations, and opportunities for advancement to reach 3D printing's full potential. PMID:27146365

  6. Tunable Microfluidic Devices for Hydrodynamic Fractionation of Cells and Beads: A Review

    Directory of Open Access Journals (Sweden)

    Jafar Alvankarian

    2015-11-01

    Full Text Available The adjustable microfluidic devices that have been developed for hydrodynamic-based fractionation of beads and cells are important for fast performance tunability through interaction of mechanical properties of particles in fluid flow and mechanically flexible microstructures. In this review, the research works reported on fabrication and testing of the tunable elastomeric microfluidic devices for applications such as separation, filtration, isolation, and trapping of single or bulk of microbeads or cells are discussed. Such microfluidic systems for rapid performance alteration are classified in two groups of bulk deformation of microdevices using external mechanical forces, and local deformation of microstructures using flexible membrane by pneumatic pressure. The main advantage of membrane-based tunable systems has been addressed to be the high capability of integration with other microdevice components. The stretchable devices based on bulk deformation of microstructures have in common advantage of simplicity in design and fabrication process.

  7. Exploiting droplet formation in microfluidic devices to create functional particles

    Science.gov (United States)

    Nowak, Emilia; Simmons, Mark

    2014-11-01

    Microfluidic devices offer excellent capabilities for the formation of microstructured particles which have functional attributes e.g. in controlled delivery of pharmaceuticals, enhanced nutrition and flavours in food. In this work, a microfluidic device is employed to form microstructured particles in two steps: (i) by formation of single/double emulsions and (ii) solidification of the droplet by either gelation or solvent evaporation. Both may impart non-Newtonian properties to the component phases. The influence of phase flow rates (capillary number), surfactant type/concentration and the rheology of the component phases upon the particle formation and hydrodynamic behaviour are described. EPSRC Programme Grant, MEMPHIS, EP/K0039761/1.

  8. Paper-based enzymatic microfluidic fuel cell: From a two-stream flow device to a single-stream lateral flow strip

    Science.gov (United States)

    González-Guerrero, Maria José; del Campo, F. Javier; Esquivel, Juan Pablo; Giroud, Fabien; Minteer, Shelley D.; Sabaté, Neus

    2016-09-01

    This work presents a first approach towards the development of a cost-effective enzymatic paper-based glucose/O2 microfluidic fuel cell in which fluid transport is based on capillary action. A first fuel cell configuration consists of a Y-shaped paper device with the fuel and the oxidant flowing in parallel over carbon paper electrodes modified with bioelectrocatalytic enzymes. The anode consists of a ferrocenium-based polyethyleneimine polymer linked to glucose oxidase (GOx/Fc-C6-LPEI), while the cathode contains a mixture of laccase, anthracene-modified multiwall carbon nanotubes, and tetrabutylammonium bromide-modified Nafion (MWCNTs/laccase/TBAB-Nafion). Subsequently, the Y-shaped configuration is improved to use a single solution containing both, the anolyte and the catholyte. Thus, the electrolytes pHs of the fuel and the oxidant solutions are adapted to an intermediate pH of 5.5. Finally, the fuel cell is run with this single solution obtaining a maximum open circuit of 0.55 ± 0.04 V and a maximum current and power density of 225 ± 17 μA cm-2 and 24 ± 5 μW cm-2, respectively. Hence, a power source closer to a commercial application (similar to conventional lateral flow test strips) is developed and successfully operated. This system can be used to supply the energy required to power microelectronics demanding low power consumption.

  9. Microfluidic Devices for Forensic DNA Analysis: A Review.

    Science.gov (United States)

    Bruijns, Brigitte; van Asten, Arian; Tiggelaar, Roald; Gardeniers, Han

    2016-01-01

    Microfluidic devices may offer various advantages for forensic DNA analysis, such as reduced risk of contamination, shorter analysis time and direct application at the crime scene. Microfluidic chip technology has already proven to be functional and effective within medical applications, such as for point-of-care use. In the forensic field, one may expect microfluidic technology to become particularly relevant for the analysis of biological traces containing human DNA. This would require a number of consecutive steps, including sample work up, DNA amplification and detection, as well as secure storage of the sample. This article provides an extensive overview of microfluidic devices for cell lysis, DNA extraction and purification, DNA amplification and detection and analysis techniques for DNA. Topics to be discussed are polymerase chain reaction (PCR) on-chip, digital PCR (dPCR), isothermal amplification on-chip, chip materials, integrated devices and commercially available techniques. A critical overview of the opportunities and challenges of the use of chips is discussed, and developments made in forensic DNA analysis over the past 10-20 years with microfluidic systems are described. Areas in which further research is needed are indicated in a future outlook. PMID:27527231

  10. Microfluidic Devices for Forensic DNA Analysis: A Review

    Science.gov (United States)

    Bruijns, Brigitte; van Asten, Arian; Tiggelaar, Roald; Gardeniers, Han

    2016-01-01

    Microfluidic devices may offer various advantages for forensic DNA analysis, such as reduced risk of contamination, shorter analysis time and direct application at the crime scene. Microfluidic chip technology has already proven to be functional and effective within medical applications, such as for point-of-care use. In the forensic field, one may expect microfluidic technology to become particularly relevant for the analysis of biological traces containing human DNA. This would require a number of consecutive steps, including sample work up, DNA amplification and detection, as well as secure storage of the sample. This article provides an extensive overview of microfluidic devices for cell lysis, DNA extraction and purification, DNA amplification and detection and analysis techniques for DNA. Topics to be discussed are polymerase chain reaction (PCR) on-chip, digital PCR (dPCR), isothermal amplification on-chip, chip materials, integrated devices and commercially available techniques. A critical overview of the opportunities and challenges of the use of chips is discussed, and developments made in forensic DNA analysis over the past 10–20 years with microfluidic systems are described. Areas in which further research is needed are indicated in a future outlook. PMID:27527231

  11. On-Chip Open Microfluidic Devices for Chemotaxis Studies

    OpenAIRE

    Wright, Gus A.; Costa, Lino; Terekhov, Alexander; Jowhar, Dawit; Hofmeister, William; Janetopoulos, Christopher

    2012-01-01

    Microfluidic devices can provide unique control over both the chemoattractant gradient and the migration environment of the cells. Our work incorporates laser-machined micro and nanofluidic channels into bulk fused silica and cover slip-sized silica wafers. We have designed “open” chemotaxis devices that produce passive chemoattractant gradients without an external micropipette system. Since the migration area is unobstructed, cells can be easily loaded and strategically placed into the devic...

  12. Droplet Formation via Solvent Shifting in a Microfluidic Device

    CERN Document Server

    Hajian, Ramin

    2014-01-01

    Solvent shifting is a process in which a non-solvent is added to a solvent/solute mixture and extracts the solvent. The solvent and the non-solvent are miscible. Because of solution supersaturation a portion of the solute transforms to droplets. In this paper, based on this process, we present an investigation on droplet formation and their radial motion in a microfluidic device in which a jet is injected in a co-flowing liquid stream. Thanks to the laminar flow, the microfluidic setup enables studying diffusion mass transfer in radial direction and obtaining well-defined concentration distributions. Such profiles together with Ternary Phase Diagram (TPD) give detailed information about the conditions for droplet formation condition as well as their radial migration in the channel. The ternary system is composed of ethanol (solvent), de-ionized water (non-solvent) and divinyle benzene (solute). We employ analytical/numerical solutions of the diffusion equation to obtain concentration profiles of the component...

  13. Development of a gas-diffusion microfluidic paper-based analytical device (μPAD) for the determination of ammonia in wastewater samples.

    Science.gov (United States)

    Jayawardane, Badra Manori; McKelvie, Ian D; Kolev, Spas D

    2015-01-01

    An inexpensive, disposable and highly selective microfluidic paper-based analytical device (μPAD) is described for the determination of ammonia (molecular ammonia and ammonium cation) in wastewaters which implements for the first time a gas-diffusion separation step on a paper-based platform. Its hydrophilic reagent zones were defined by printing filter paper with a hydrophobic paper sizing agent using a conventional inkjet printer. The sample was introduced into the sodium hydroxide impregnated sample zone of the μPAD. This allowed the quantitative conversion of the ammonium ion to molecular ammonia which diffused across the hydrophobic microporous Teflon membrane of the device into an adjacent hydrophilic reagent zone containing the acid-base indicator 3-nitrophenol or bromothymol blue. The change in indicator color was measured using a desktop scanner for ammonia quantification. Under optimal conditions, the μPAD is characterized by a limit of detection of 0.8 and 1.8 mg N L(-1) and repeatability of 3.1 and 3.7% (n ≥ 10, 20 mg N L(-1)), expressed as relative standard deviation, in the case of 3-nitrophenol or bromothymol blue, respectively. This μPAD was used successfully for the determination of ammonia in sewage and soil water samples. The small dimensions, minimal reagent consumption, low cost, simplicity of operation, and possibility of using a portable scanner make the proposed μPAD suitable for on-site ammonia monitoring in contaminated environmental waters and domestic, agricultural and industrial wastewaters. The successful implementation of the gas-diffusion approach on a paper-based platform is expected to result in the development of other μPADs for volatile analytes.

  14. High-throughput rheology in a microfluidic device

    Science.gov (United States)

    Furst, Eric; Schultz, Kelly; Han, Hyejin; Kim, Chongyoup

    2011-11-01

    High-throughput rheological measurements in a microfluidic device are demonstrated. A series of microrheology samples is generated as droplets in an immiscible spacer fluid using a microfluidic T-junction. The compositions of the sample droplets are continuously varied over a wide range. Rheology measurements are made in each droplet using multiple particle tracking microrheology. We review critical design and operating parameters, including the droplet size, flow rates and rapid fabrication methods. Validation experiments are performed by measuring the solution viscosity of glycerine and the biopolymer heparin as a function of concentration. Finally, an analysis of droplet mixing is performed in order to optimize the device performance. Overall, the combination of microrheology with microfluidics maximizes the number of rheological measurements while simultaneously minimizing the sample preparation time and amount of material, and should be particularly suited to the characterization of scarce or expensive materials. We acknowledge financial support from the NSF (CBET-0730292).

  15. Microfluidic baker's transformation device for three-dimensional rapid mixing.

    Science.gov (United States)

    Yasui, Takao; Omoto, Yusuke; Osato, Keiko; Kaji, Noritada; Suzuki, Norikazu; Naito, Toyohiro; Watanabe, Masaki; Okamoto, Yukihiro; Tokeshi, Manabu; Shamoto, Eiji; Baba, Yoshinobu

    2011-10-01

    We developed a new passive-type micromixer based on the baker's transformation and realized a fast mixing of a protein solution, which has lower diffusion constant. The baker's transformation is an ideal mixing method, but there is no report on the microfluidic baker's transformation (MBT), since it is required to fabricate the complicated three-dimensional (3D) structure to realize the MBT device. In this note, we successfully fabricate the MBT device by using precision diamond cutting of an oxygen-free copper substrate for the mould fabrication and PDMS replication. The MBT device with 10.4 mm mixing length enables us to achieve complete mixing of a FITC solution (D = 2.6 × 10(-10) m(2) s(-1)) within 51 ms and an IgG solution (D = 4.6 × 10(-11) m(2) s(-1)) within 306 ms. Its mixing speed is 70-fold higher for a FITC solution and 900-fold higher for an IgG solution than the mixing speed by the microchannel without MBT structures. The Péclet number to attain complete mixing in the MBT device is estimated to be 6.9 × 10(4).

  16. Stimulus-active polymer actuators for next-generation microfluidic devices

    Science.gov (United States)

    Hilber, Wolfgang

    2016-08-01

    Microfluidic devices have not yet evolved into commercial off-the-shelf products. Although highly integrated microfluidic structures, also known as lab-on-a-chip (LOC) and micrototal-analysis-system (µTAS) devices, have consistently been predicted to revolutionize biomedical assays and chemical synthesis, they have not entered the market as expected. Studies have identified a lack of standardization and integration as the main obstacles to commercial breakthrough. Soft microfluidics, the utilization of a broad spectrum of soft materials (i.e., polymers) for realization of microfluidic components, will make a significant contribution to the proclaimed growth of the LOC market. Recent advances in polymer science developing novel stimulus-active soft-matter materials may further increase the popularity and spreading of soft microfluidics. Stimulus-active polymers and composite materials change shape or exert mechanical force on surrounding fluids in response to electric, magnetic, light, thermal, or water/solvent stimuli. Specifically devised actuators based on these materials may have the potential to facilitate integration significantly and hence increase the operational advantage for the end-user while retaining cost-effectiveness and ease of fabrication. This review gives an overview of available actuation concepts that are based on functional polymers and points out promising concepts and trends that may have the potential to promote the commercial success of microfluidics.

  17. Diffusionless fluid transport and routing using novel microfluidic devices.

    Energy Technology Data Exchange (ETDEWEB)

    Barrett, Louise Mary; Shediac, Renee; Reichmuth, David S.

    2006-11-01

    Microfluidic devices have been proposed for 'Lab-on-a-Chip' applications for nearly a decade. Despite the unquestionable promise of these devices to allow rapid, sensitive and portable biochemical analysis, few practical devices exist. It is often difficult to adapt current laboratory techniques to the microscale because bench-top methods use discrete liquid volumes, while most current microfluidic devices employ streams of liquid confined in a branching network of micron-scale channels. The goal of this research was to use two phase liquid flows, creating discrete packets of liquid. Once divided into discrete packets, the packets can be moved controllably within the microchannels without loss of material. Each packet is equivalent to a minute test tube, holding a fraction from a separation or an aliquot to be reacted. We report on the fabrication of glass and PDMS (polydimethylsiloxane) devices that create and store packets.

  18. Hard top soft bottom microfluidic devices for cell culture and chemical analysis.

    Science.gov (United States)

    Mehta, Geeta; Lee, Jay; Cha, Wansik; Tung, Yi-Chung; Linderman, Jennifer J; Takayama, Shuichi

    2009-05-15

    We report fabrication and characterization of microfluidic devices made of thermoplastic and elastomeric polymers. These hard-soft hybrid material devices are motivated by the combined need for large scale manufacturability, enhanced barrier properties to gas permeation and evaporation of aqueous solutions compared to poly(dimethyl siloxane) (PDMS) devices, and compatibility with deformation-based actuation. Channel features are created on rigid polymers such as polyethylene terephthalate glycol (PETG), cyclic olefin copolymer (COC), and polystyrene (PS) by hot embossing. These "hard tops" are bonded to elastomeric "soft bottoms" (polyurethane (PU) or PDMS-parylene C-PDMS) to create devices that can be used for microfluidic cell culture where deformation-based fluid actuation schemes are used to perfuse and recirculate media. The higher barrier properties of this device compared to PDMS devices enable cell culture with less evaporation and creation of hypoxic conditions. PMID:19382754

  19. Solvent-resistant photocurable liquid fluoropolymers for microfluidic device fabrication [corrected].

    Science.gov (United States)

    Rolland, Jason P; Van Dam, R Michael; Schorzman, Derek A; Quake, Stephen R; DeSimone, Joseph M

    2004-03-01

    We report the first fabrication of a solvent-compatible microfluidic device based on photocurable "Liquid Teflon" materials. The materials are highly fluorinated functionalized perfluoropolyethers (PFPEs) that have liquidlike viscosities that can be cured into tough, highly durable elastomers that exhibit the remarkable chemical resistance of fluoropolymers such as Teflon. Poly(dimethylsiloxane) (PDMS) elastomers have rapidly become the material of choice for many recent microfluidic device applications. Despite the advantages of PDMS in relation to microfluidics technology, the material suffers from a serious drawback in that it swells in most organic solvents. The swelling of PDMS-based devices in organic solvents greatly disrupts the micrometer-sized features and makes it impossible for fluids to flow inside the channels. Our approach to this problem has been to replace PDMS with photocurable perfluoropolyethers. Device fabrication and valve actuation were accomplished using established procedures for PDMS devices. The additional advantage of photocuring allows fabrication time to be decreased from several hours to a matter of minutes. The PFPE-based device exhibited mechanical properties similar to those of Sylgard 184 before and after curing as well as remarkable resistance to organic solvents. This work has the potential to expand the field of microfluidics to many novel applications.

  20. Hybrid Integrated Silicon Microfluidic Platform for Fluorescence Based Biodetection

    Directory of Open Access Journals (Sweden)

    André Darveau

    2007-09-01

    Full Text Available The desideratum to develop a fully integrated Lab-on-a-chip device capable ofrapid specimen detection for high throughput in-situ biomedical diagnoses and Point-of-Care testing applications has called for the integration of some of the novel technologiessuch as the microfluidics, microphotonics, immunoproteomics and Micro ElectroMechanical Systems (MEMS. In the present work, a silicon based microfluidic device hasbeen developed for carrying out fluorescence based immunoassay. By hybrid attachment ofthe microfluidic device with a Spectrometer-on-chip, the feasibility of synthesizing anintegrated Lab-on-a-chip type device for fluorescence based biosensing has beendemonstrated. Biodetection using the microfluidic device has been carried out usingantigen sheep IgG and Alexafluor-647 tagged antibody particles and the experimentalresults prove that silicon is a compatible material for the present application given thevarious advantages it offers such as cost-effectiveness, ease of bulk microfabrication,superior surface affinity to biomolecules, ease of disposability of the device etc., and is thussuitable for fabricating Lab-on-a-chip type devices.

  1. Microfluidic devices and methods including porous polymer monoliths

    Science.gov (United States)

    Hatch, Anson V; Sommer, Gregory J; Singh, Anup K; Wang, Ying-Chih; Abhyankar, Vinay V

    2014-04-22

    Microfluidic devices and methods including porous polymer monoliths are described. Polymerization techniques may be used to generate porous polymer monoliths having pores defined by a liquid component of a fluid mixture. The fluid mixture may contain iniferters and the resulting porous polymer monolith may include surfaces terminated with iniferter species. Capture molecules may then be grafted to the monolith pores.

  2. Chromatic analysis by monitoring unmodified silver nanoparticles reduction on double layer microfluidic paper-based analytical devices for selective and sensitive determination of mercury(II).

    Science.gov (United States)

    Meelapsom, Rattapol; Jarujamrus, Purim; Amatatongchai, Maliwan; Chairam, Sanoe; Kulsing, Chadin; Shen, Wei

    2016-08-01

    This study demonstrates chromatic analysis based on a simple red green blue (RGB) color model for sensitive and selective determination of mercury(II). The analysis was performed by monitoring the color change of a microfluidic Paper-based Analytical Device (µPAD). The device was fabricated by using alkyl ketene dimer (AKD)-inkjet printing and doped with unmodified silver nanoparticles (AgNPs) which were disintegrated when being exposed to mercury(II). The color intensity was detected by using an apparatus consisting of a digital camera and a homemade light box generating constant light intensity. A progressive increase in color intensity of the tested area on the µPAD (3.0mm) was observed with increasing mercury(II) concentration. The developed system enabled quantification of mercury(II) at low concentration with the detection limit of 0.001mgL(-1) (3 SD blank/slope of the calibration curve) and small sample volume uptake (2µL). The linearity range of the calibration curve in this technique was demonstrated from 0.05 to 7mgL(-1) (r(2)=0.998) with good precision (RSD less than 4.1%). Greater selectivity towards mercury(II) compared with potential interference ions was also observed. Furthermore, the percentage recoveries of spiked water samples were in an acceptable range which was in agreement with the values obtained from the conventional method utilizing cold vapor atomic absorption spectrometer (CVAAS). The proposed technique allows a rapid, simple, sensitive and selective analysis of trace mercury(II) in water samples. PMID:27216673

  3. Chromatic analysis by monitoring unmodified silver nanoparticles reduction on double layer microfluidic paper-based analytical devices for selective and sensitive determination of mercury(II).

    Science.gov (United States)

    Meelapsom, Rattapol; Jarujamrus, Purim; Amatatongchai, Maliwan; Chairam, Sanoe; Kulsing, Chadin; Shen, Wei

    2016-08-01

    This study demonstrates chromatic analysis based on a simple red green blue (RGB) color model for sensitive and selective determination of mercury(II). The analysis was performed by monitoring the color change of a microfluidic Paper-based Analytical Device (µPAD). The device was fabricated by using alkyl ketene dimer (AKD)-inkjet printing and doped with unmodified silver nanoparticles (AgNPs) which were disintegrated when being exposed to mercury(II). The color intensity was detected by using an apparatus consisting of a digital camera and a homemade light box generating constant light intensity. A progressive increase in color intensity of the tested area on the µPAD (3.0mm) was observed with increasing mercury(II) concentration. The developed system enabled quantification of mercury(II) at low concentration with the detection limit of 0.001mgL(-1) (3 SD blank/slope of the calibration curve) and small sample volume uptake (2µL). The linearity range of the calibration curve in this technique was demonstrated from 0.05 to 7mgL(-1) (r(2)=0.998) with good precision (RSD less than 4.1%). Greater selectivity towards mercury(II) compared with potential interference ions was also observed. Furthermore, the percentage recoveries of spiked water samples were in an acceptable range which was in agreement with the values obtained from the conventional method utilizing cold vapor atomic absorption spectrometer (CVAAS). The proposed technique allows a rapid, simple, sensitive and selective analysis of trace mercury(II) in water samples.

  4. Mail-Order Microfluidics: Evaluation of Stereolithography for the Production of Microfluidic Devices

    OpenAIRE

    Au, Anthony K.; Lee, Wonjae; Folch, Albert

    2014-01-01

    The vast majority of microfluidic devices are developed in PDMS by molding (“soft lithography”) because PDMS is an inexpensive material, has physicochemical properties that are well suited for biomedical and physical sciences applications, and design cycle lengths are generally adequate for prototype development. However, PDMS molding is tediously slow and thus cannot provide the high- or medium-volume production required for the commercialization of devices. While high-throughput plastic mol...

  5. A Sensitive Chemotaxis Assay Using a Novel Microfluidic Device

    Directory of Open Access Journals (Sweden)

    Chen Zhang

    2013-01-01

    Full Text Available Existing chemotaxis assays do not generate stable chemotactic gradients and thus—over time—functionally measure only nonspecific random motion (chemokinesis. In comparison, microfluidic technology has the capacity to generate a tightly controlled microenvironment that can be stably maintained for extended periods of time and is, therefore, amenable to adaptation for assaying chemotaxis. We describe here a novel microfluidic device for sensitive assay of cellular migration and show its application for evaluating the chemotaxis of smooth muscle cells in a chemokine gradient.

  6. A new UV-curing elastomeric substrate for rapid prototyping of microfluidic devices

    International Nuclear Information System (INIS)

    Rapid prototyping in the design cycle of new microfluidic devices is very important for shortening time-to-market. Researchers are facing the challenge to explore new and suitable substrates with simple and efficient microfabrication techniques. In this paper, we introduce and characterize a UV-curing elastomeric polyurethane methacrylate (PUMA) for rapid prototyping of microfluidic devices. The swelling and solubility of PUMA in different chemicals is determined. Time-dependent measurements of water contact angle show that the native PUMA is hydrophilic without surface treatment. The current monitoring method is used for measurement of the electroosmotic flow mobility in the microchannels made from PUMA. The optical, physical, thermal and mechanical properties of PUMA are evaluated. The UV-lithography and molding process is used for making micropillars and deep channel microfluidic structures integrated to the supporting base layer. Spin coating is characterized for producing different layer thicknesses of PUMA resin. A device is fabricated and tested for examining the strength of different bonding techniques such as conformal, corona treating and semi-curing of two PUMA layers in microfluidic application and the results show that the bonding strengths are comparable to that of PDMS. We also report fabrication and testing of a three-layer multi inlet/outlet microfluidic device including a very effective fluidic interconnect for application demonstration of PUMA as a promising new substrate. A simple micro-device is developed and employed for observing the pressure deflection of membrane made from PUMA as a very effective elastomeric valve in microfluidic devices. (paper)

  7. 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. PMID:27131999

  8. A Comprehensive Microfluidics Device Construction and Characterization Module for the Advanced Undergraduate Analytical Chemistry Laboratory

    Science.gov (United States)

    Piunno, Paul A. E.; Zetina, Adrian; Chu, Norman; Tavares, Anthony J.; Noor, M. Omair; Petryayeva, Eleonora; Uddayasankar, Uvaraj; Veglio, Andrew

    2014-01-01

    An advanced analytical chemistry undergraduate laboratory module on microfluidics that spans 4 weeks (4 h per week) is presented. The laboratory module focuses on comprehensive experiential learning of microfluidic device fabrication and the core characteristics of microfluidic devices as they pertain to fluid flow and the manipulation of samples.…

  9. Dried reagents for multiplex genotyping by tag-array minisequencing to be used in microfluidic devices

    DEFF Research Database (Denmark)

    Ahlford, Annika; Kjeldsen, Bastian; Reimers, Jakob;

    2010-01-01

    was carried out with freeze-dried reagents stored in reaction chambers fabricated by micromilling in a cyclic olefin copolymer substrate. The results reported in this study are a key step towards the development of an integrated microfluidic device for point-of-care DNA-based diagnostics....

  10. A Supramolecular Sensing Platform for Phosphate Anions and an Anthrax Biomarker in a Microfluidic Device

    NARCIS (Netherlands)

    Eker, Bilge; Yilmaz, Mahmut Deniz; Schlautmann, Stefan; Gardeniers, Johannes G.E.; Huskens, Jurriaan

    2011-01-01

    A supramolecular platform based on self-assembled monolayers (SAMs) has been implemented in a microfluidic device. The system has been applied for the sensing of two different analyte types: biologically relevant phosphate anions and aromatic carboxylic acids, which are important for anthrax detecti

  11. Low-cost bioanalysis on paper-based and its hybrid microfluidic platforms.

    Science.gov (United States)

    Dou, Maowei; Sanjay, Sharma Timilsina; Benhabib, Merwan; Xu, Feng; Li, XiuJun

    2015-12-01

    Low-cost assays have broad applications ranging from human health diagnostics and food safety inspection to environmental analysis. Hence, low-cost assays are especially attractive for rural areas and developing countries, where financial resources are limited. Recently, paper-based microfluidic devices have emerged as a low-cost platform which greatly accelerates the point of care (POC) analysis in low-resource settings. This paper reviews recent advances of low-cost bioanalysis on paper-based microfluidic platforms, including fully paper-based and paper hybrid microfluidic platforms. In this review paper, we first summarized the fabrication techniques of fully paper-based microfluidic platforms, followed with their applications in human health diagnostics and food safety analysis. Then we highlighted paper hybrid microfluidic platforms and their applications, because hybrid platforms could draw benefits from multiple device substrates. Finally, we discussed the current limitations and perspective trends of paper-based microfluidic platforms for low-cost assays.

  12. Molecular Probes for Thermometry in Microfluidic Devices

    Science.gov (United States)

    Gosse, Charlie; Bergaud, Christian; Löw, Peter

    The temperature is an important parameter with regard to chemical reactivity. It is therefore essential to ensure good thermal control within microsystems designed to carry out biological analysis. We begin by reviewing temperature measurement in the context of the lab-on-a-chip, and outlining the various generic strategies available. We then turnmore specifically to luminescentmolecular probes.We shall show that they all exploit the effect of temperature on a chemical reaction (in the broad sense of the term). More precisely, these probes can be divided in three main categories depending on whether one relies on a phase transition, the modification of a reaction rate, or a shift in an equilibrium. We shall also discuss the main experimental strategies used to transform the image obtained by fluorescence microscopy into a thermal map. Finally, we shall extend the discussion to a few other spectroscopic techniques and examine the prospects for this particular area of microfluidics.

  13. Flash μ-fluidics: a rapid prototyping method for fabricating microfluidic devices

    KAUST Repository

    Buttner, Ulrich

    2016-08-01

    Microfluidics has advanced in terms of design and structures; however, fabrication methods are time-consuming or expensive relative to facility costs and equipment needed. This work demonstrates a fast and economically viable 2D/3D maskless digital light-projection method based on a stereolithography process. Unlike other fabrication methods, one exposure step is used to form the whole device. Flash microfluidics is achieved by incorporating bonding and channel fabrication of complex structures in just 2.5 s to 4 s and by fabricating channel heights between 25 μm and 150 μm with photopolymer resin. The features of this fabrication technique, such as time and cost saving and easy fabrication, are used to build devices that are mostly needed in microfluidic/lab-on-chip systems. Due to the fast production method and low initial setup costs, the process could be used for point of care applications. © 2016 The Royal Society of Chemistry.

  14. Microfluidic Device for Controllable Chemical Release via Field-Actuated Membrane Incorporating Nanoparticles

    KAUST Repository

    Wang, Xiang

    2013-01-01

    We report a robust magnetic-membrane-based microfluidic platform for controllable chemical release. The magnetic membrane was prepared by mixing polydimethylsiloxane (PDMS) and carbonyl-iron nanoparticles together to obtain a flexible thin film. With combined, simultaneous regulation of magnetic stimulus and mechanical pumping, the desired chemical release rate can easily be realized. For example, the dose release experimental data was well fitted by a mathematical sigmoidal model, exhibiting a typical dose-response relationship, which shows promise in providing significant guidance for on-demand drug delivery. To test the platform’s feasibility, our microfluidic device was employed in an experiment involving Escherichia coli culture under controlled antibiotic ciprofloxacin exposure, and the expected outcomes were successfully obtained. Our experimental results indicate that such a microfluidic device, with high accuracy and easy manipulation properties, can legitimately be characterized as active chemical release system.

  15. Microfluidic Device for Controllable Chemical Release via Field-Actuated Membrane Incorporating Nanoparticles

    Directory of Open Access Journals (Sweden)

    Xiang Wang

    2013-01-01

    Full Text Available We report a robust magnetic-membrane-based microfluidic platform for controllable chemical release. The magnetic membrane was prepared by mixing polydimethylsiloxane (PDMS and carbonyl-iron nanoparticles together to obtain a flexible thin film. With combined, simultaneous regulation of magnetic stimulus and mechanical pumping, the desired chemical release rate can easily be realized. For example, the dose release experimental data was well fitted by a mathematical sigmoidal model, exhibiting a typical dose-response relationship, which shows promise in providing significant guidance for on-demand drug delivery. To test the platform’s feasibility, our microfluidic device was employed in an experiment involving Escherichia coli culture under controlled antibiotic ciprofloxacin exposure, and the expected outcomes were successfully obtained. Our experimental results indicate that such a microfluidic device, with high accuracy and easy manipulation properties, can legitimately be characterized as active chemical release system.

  16. Interconnection blocks with minimal dead volumes permitting planar interconnection to thin microfluidic devices

    DEFF Research Database (Denmark)

    Sabourin, David; Snakenborg, Detlef; Dufva, Martin

    2010-01-01

    We have previously described 'Interconnection Blocks' which are re-usable, non-integrated PDMS blocks which allowing multiple, aligned and planar microfluidic interconnections. Here, we describe Interconnection Block versions with zero dead volumes that allow fluidic interfacing to flat or thin...... side-walled microfluidic devices. These designs increase the number of materials, types of devices and applications for which Interconnection Blocks can be used. Average leak pressures of 4.7 bar were recorded and all individual leak pressures recorded were above the 2-bar threshold for microfluidic...... applications. Additionally, the new Interconnection Block designs demonstrate that micromilling, a practical microfabrication method, can produce useful geometries not readily made through clean room-based approaches....

  17. Development of a biomimetic microfluidic oxygen transfer device.

    Science.gov (United States)

    Gimbel, A A; Flores, E; Koo, A; García-Cardeña, G; Borenstein, J T

    2016-08-16

    Blood oxygenators provide crucial life support for patients suffering from respiratory failure, but their use is severely limited by the complex nature of the blood circuit and by complications including bleeding and clotting. We have fabricated and tested a multilayer microfluidic blood oxygenation prototype designed to have a lower blood prime volume and improved blood circulation relative to current hollow fiber cartridge oxygenators. Here we address processes for scaling the device toward clinically relevant oxygen transfer rates while maintaining a low prime volume of blood in the device, which is required for clinical applications in cardiopulmonary support and ultimately for chronic use. Approaches for scaling the device toward clinically relevant gas transfer rates, both by expanding the active surface area of the network of blood microchannels in a planar layer and by increasing the number of microfluidic layers stacked together in a three-dimensional device are addressed. In addition to reducing prime volume and enhancing gas transfer efficiency, the geometric properties of the microchannel networks are designed to increase device safety by providing a biomimetic and physiologically realistic flow path for the blood. Safety and hemocompatibility are also influenced by blood-surface interactions within the device. In order to further enhance device safety and hemocompatibility, we have demonstrated successful coating of the blood flow pathways with human endothelial cells, in order to confer the ability of the endothelium to inhibit coagulation and thrombus formation. Blood testing results provide confirmation of fibrin clot formation in non-endothelialized devices, while negligible clot formation was documented in cell-coated devices. Gas transfer testing demonstrates that the endothelial lining does not reduce the transfer efficiency relative to acellular devices. This process of scaling the microfluidic architecture and utilizing autologous cells to

  18. A microfluidic device with a diffusion barrier

    DEFF Research Database (Denmark)

    2014-01-01

    The invention provides a microfiuidic device for macromoiecuie amplification by sequential addition of liquid reagents. The device of the invention comprises a chip forming a plurality of reaction chambers each extending between an inlet and an outlet, each inlet being in fluid communication...... with a common junction via micro channels. To enable amplification of DNA, e.g. by MDA, the device comprises a diffusion barrier at each inlet configured to increase the pressure threshold for a reagent to cross the resistor. The invention further provides a method of mixing liquid reagents by use of the device...

  19. All-polymer microfluidic systems for droplet based sample analysis

    DEFF Research Database (Denmark)

    Poulsen, Carl Esben

    In this PhD project, I pursued to develop an all-polymer injection moulded microfluidic platform with integrated droplet based single cell interrogation. To allow for a proper ”one device - one experiment” methodology and to ensure a high relevancy to non-academic settings, the systems presented ...

  20. Magnetic Graphene Nanosheet-Based Microfluidic Device for Homogeneous Real-Time Electronic Monitoring of Pyrophosphatase Activity Using Enzymatic Hydrolysate-Induced Release of Copper Ion.

    Science.gov (United States)

    Lin, Youxiu; Zhou, Qian; Li, Juan; Shu, Jian; Qiu, Zhenli; Lin, Yuping; Tang, Dianping

    2016-01-01

    A novel flow-through microfluidic device based on a magneto-controlled graphene sensing platform was designed for homogeneous electronic monitoring of pyrophosphatase (PPase) activity; enzymatic hydrolysate-induced release of inorganic copper ion (Cu(2+)) from the Cu(2+)-coordinated pyrophosphate ions (Cu(2+)-PPi) complex was assessed to determine enzyme activity. Magnetic graphene nanosheets (MGNS) functionalized with negatively charged Nafion were synthesized by using the wet-chemistry method. The Cu(2+)-PPi complexes were prepared on the basis of the coordination reaction between copper ion and inorganic pyrophosphate ions. Upon target PPase introduction into the detection system, the analyte initially hydrolyzed pyrophosphate ions into phosphate ions and released the electroactive copper ions from Cu(2+)-PPi complexes. The released copper ions could be readily captured through the negatively charged Nafion on the magnetic graphene nanosheets, which could be quantitatively monitored by using the stripping voltammetry on the flow-through detection cell with an external magnet. Under optimal conditions, the obtained electrochemical signal exhibited a high dependence on PPase activity within a dynamic range from 0.1 to 20 mU mL(-1) and allowed the detection at a concentration as low as 0.05 mU mL(-1). Coefficients of variation for reproducibility of the intra-assay and interassay were below 7.6 and 9.8%, respectively. The inhibition efficiency of sodium fluoride (NaF) also received good results in pyrophosphatase inhibitor screening research. In addition, the methodology afforded good specificity and selectivity, simplification, and low cost without the need of sample separations and multiple washing steps, thus representing a user-friendly protocol for practical utilization in a quantitative PPase activity.

  1. A microfluidic paper-based electrochemical biosensor array for multiplexed detection of metabolic biomarkers

    OpenAIRE

    Chen Zhao, Martin M Thuo and Xinyu Liu

    2013-01-01

    Paper-based microfluidic devices have emerged as simple yet powerful platforms for performing low-cost analytical tests. This paper reports a microfluidic paper-based electrochemical biosensor array for multiplexed detection of physiologically relevant metabolic biomarkers. Different from existing paper-based electrochemical devices, our device includes an array of eight electrochemical sensors and utilizes a handheld custom-made electrochemical reader (potentiostat) for signal readout. The b...

  2. A Microfluidic Device for Continuous-Flow Magnetically Controlled Capture and Isolation of Microparticles

    OpenAIRE

    Zhou, Yao; Wang, Yi; Lin, Qiao

    2010-01-01

    This paper presents a novel microfluidic device that exploits magnetic manipulation for integrated capture and isolation of microparticles in continuous flow. The device, which was fabricated from poly(dimethylsiloxane) (PDMS) by soft-lithography techniques, consists of an incubator and a separator integrated on a single chip. The incubator is based on a novel scheme termed target acquisition by repetitive traversal (TART), in which surface-functionalized magnetic beads repetitively traverse ...

  3. Large-Scale Integration of All-Glass Valves on a Microfluidic Device

    OpenAIRE

    Yaxiaer Yalikun; Yo Tanaka

    2016-01-01

    In this study, we developed a method for fabricating a microfluidic device with integrated large-scale all-glass valves and constructed an actuator system to control each of the valves on the device. Such a microfluidic device has advantages that allow its use in various fields, including physical, chemical, and biochemical analyses and syntheses. However, it is inefficient and difficult to integrate the large-scale all-glass valves in a microfluidic device using conventional glass fabricatio...

  4. Simulation of magnetic active polymers for versatile microfluidic devices

    OpenAIRE

    Binder Claudia; Kataeva Nadezhda; Bance Simon; Exl Lukas; Reichel Franz; Fischbacher Johann; Özelt Harald; Gusenbauer Markus; Brückl Hubert; Schrefl Thomas

    2013-01-01

    We propose to use a compound of magnetic nanoparticles (20-100 nm) embedded in a flexible polymer (Polydimethylsiloxane PDMS) to filter circulating tumor cells (CTCs). The analysis of CTCs is an emerging tool for cancer biology research and clinical cancer management including the detection, diagnosis and monitoring of cancer. The combination of experiments and simulations lead to a versatile microfluidic lab-on-chip device. Simulations are essential to understand the influence of the embedde...

  5. Microfluidic Devices for Manipulation and Detection of Beads and Biomolecules

    OpenAIRE

    Jönsson, Mats

    2006-01-01

    This thesis summarises work towards a Lab-on-Chip (LOC). The request for faster and more efficient chemical and biological analysis is the motivation behind the development of the LOC-concept. Microfluidic devices tend to become increasingly complex in order to include, e.g. sample delivery, manipulation, and detection, in one chip. The urge for smart and simple design of robust and low-cost microdevices is addressed and discussed. Design, fabrication and characterization of such microdevices...

  6. Routing-based synthesis of digital microfluidic biochips

    DEFF Research Database (Denmark)

    Maftei, Elena; Pop, Paul; Madsen, Jan

    2012-01-01

    Microfluidic biochips are replacing the conventional biochemical analyzers, and are able to integrate on-chip all the necessary functions for biochemical analysis. The “digital” biochips are manipulating liquids as discrete droplets on a two-dimensional array of electrodes. Basic microfluidic...... of virtual devices and allow the droplets to move on the chip on any route during operation execution. Thus, the synthesis problem is transformed into a routing problem. We develop an algorithm based on a Greedy Randomized Adaptive Search Procedure (GRASP) and we show that routing-based synthesis leads...

  7. A Pneumatic Actuated Microfluidic Beads-Trapping Device

    Energy Technology Data Exchange (ETDEWEB)

    Shao, Guocheng; Cai, Ziliang; Wang, Jun; Wang, Wanjun; Lin, Yuehe

    2011-08-20

    The development of a polydimethylsiloxane (PDMS) microfluidic microbeads trapping device is reported in this paper. Besides fluid channels, the proposed device includes a pneumatic control chamber and a beads-trapping chamber with a filter array structure. The pneumatic flow control chamber and the beads-trapping chamber are vertically stacked and separated by a thin membrane. By adjusting the pressure in the pneumatic control chamber, the membrane can either be pushed against the filter array to set the device in trapping mode or be released to set the device in releasing mode. In this paper, a computational fluid dynamics simulation was conducted to optimize the geometry design of the filter array structure; the device fabrication was also carried out. The prototype device was tested and the preliminary experimental results showed that it can be used as a beads-trapping unit for various biochemistry and analytical chemistry applications, especially for flow injection analysis systems.

  8. Thermal assisted ultrasonic bonding of multilayer polymer microfluidic devices

    International Nuclear Information System (INIS)

    A new approach to fabricating multilayer microfluidic devices of poly(methyl methacrylate) (PMMA) was presented. Substrates were preheated to 20–30 °C lower than glass transition temperature (Tg) of the material by a hot plate. Then low-amplitude ultrasonic vibration was employed to generate facial heat at the interface of the PMMA layers. Two crossover micro-separation channel networks and a micro mixer were integrated in a four-layer microfluidic device using this method. The burst pressure of the bonded channel was more than 0.65 MPa. In order to demonstrate the performance of this technique, as many as 12 PMMA layers with micro-channels were successfully bonded together at one time. The average depth loss ratio of micro-channels was 0.6% and the tensile strength was 0.67 MPa. Multilayer poly(ethylene terephthalate) (PET) and cyclo-olefin polymer (COP) substrates were also successfully bonded. This study provided a potential method for constructing complex channel networks for polymer microfluidic devices

  9. Buckling delamination induced microchannel: Flow regulation in microfluidic devices

    Science.gov (United States)

    Kang, Jingtian; Wang, Changguo; Xue, Zhiming; Liu, Mengxiong; Tan, Huifeng

    2016-09-01

    The buckling delamination induced microchannel is employed to regulate fluid flow as a microvalve which can be utilized in microfluidic devices. This microvalve consists of a soft substrate and a stiff thin film, between which there is a pre-set small imperfection. Two critical strain values, namely, on-off strain and failure strain, have been proposed to determine the working strain interval using analytical predictions. Within this interval, the cross-sectional area of the microchannel can be controlled and predicted by different compressive strains of the film/substrate system. The fluid flow rate within this microchannel can be then estimated by both analytical and numerical simulations and adjusted to satisfy different values by alternating the compressive strain. In addition, a demonstrative experiment has been taken to verify the feasibility of this approach. This flexible microvalve has potential in the application where the use of traditional rigid microvalves is improper in flexible microfluidic devices. The method and approach of this paper can provide a general guide for flow rate control in microfluidic devices.

  10. A simple method of fabricating mask-free microfluidic devices for biological analysis.

    KAUST Repository

    Yi, Xin

    2010-09-07

    We report a simple, low-cost, rapid, and mask-free method to fabricate two-dimensional (2D) and three-dimensional (3D) microfluidic chip for biological analysis researches. In this fabrication process, a laser system is used to cut through paper to form intricate patterns and differently configured channels for specific purposes. Bonded with cyanoacrylate-based resin, the prepared paper sheet is sandwiched between glass slides (hydrophilic) or polymer-based plates (hydrophobic) to obtain a multilayer structure. In order to examine the chip\\'s biocompatibility and applicability, protein concentration was measured while DNA capillary electrophoresis was carried out, and both of them show positive results. With the utilization of direct laser cutting and one-step gas-sacrificing techniques, the whole fabrication processes for complicated 2D and 3D microfluidic devices are shorten into several minutes which make it a good alternative of poly(dimethylsiloxane) microfluidic chips used in biological analysis researches.

  11. 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...

  12. Real-time measurement of flow rate in microfluidic devices using a cantilever-based optofluidic sensor.

    Science.gov (United States)

    Cheri, Mohammad Sadegh; Latifi, Hamid; Sadeghi, Jalal; Moghaddam, Mohammadreza Salehi; Shahraki, Hamidreza; Hajghassem, Hasan

    2014-01-21

    Real-time and accurate measurement of flow rate is an important reqirement in lab on a chip (LOC) and micro total analysis system (μTAS) applications. In this paper, we present an experimental and numerical investigation of a cantilever-based optofluidic flow sensor for this purpose. Two sensors with thin and thick cantilevers were fabricated by engraving a 2D pattern of cantilever/base on two polymethylmethacrylate (PMMA) slabs using a CO2 laser system and then casting a 2D pattern with polydimethylsiloxane (PDMS). The basic working principle of the sensor is the fringe shift of the Fabry-Pérot (FP) spectrum due to a changing flow rate. A Finite Element Method (FEM) is used to solve the three dimensional (3D) Navier-Stokes and structural deformation equations to simulate the pressure distribution, velocity and cantilever deflection results of the flow in the channel. The experimental results show that the thin and thick cantilevers have a minimum detectable flow change of 1.3 and 4 (μL min(-1)) respectively. In addition, a comparison of the numerical and experimental deflection of the cantilever has been done to obtain the effective Young's modulus of the thin and thick PDMS cantilevers. PMID:24291805

  13. Generation of emulsion droplets and micro-bubbles in microfluidic devices

    KAUST Repository

    Zhang, Jiaming

    2016-04-01

    Droplet-based microfluidic devices have become a preferred versatile platform for various fields in physics, chemistry and biology to manipulate small amounts of liquid samples. In addition to microdroplets, microbubbles are also needed for various pro- cesses in the food, healthcare and cosmetic industries. Polydimethylsiloxane (PDMS) soft lithography, the mainstay for fabricating microfluidic devices, usually requires the usage of expensive apparatus and a complex manufacturing procedure. In ad- dition, current methods have the limited capabilities for fabrication of microfluidic devices within three dimensional (3D) structures. Novel methods for fabrication of droplet-based microfluidic devices for the generation microdroplets and microbubbles are therefore of great interest in current research. In this thesis, we have developed several simple, rapid and low-cost methods for fabrication of microfluidic devices, especially for generation of microdroplets and mi- crobubbles. We first report an inexpensive full-glass microfluidic devices with as- sembly of glass capillaries, for generating monodisperse multiple emulsions. Different types of devices have been designed and tested and the experimental results demon- strated the robust capability of preparing monodisperse single, double, triple and multi-component emulsions. Second, we propose a similar full-glass device for generation of microbubbles, but with assembly of a much smaller nozzle of a glass capillary. Highly monodisperse microbubbles with diameter range from 3.5 to 60 microns have been successfully produced, at rates up to 40 kHz. A simple scaling law based on the capillary number and liquid-to-gas flow rate ratio, successfully predicts the bubble size. Recently, the emergent 3D printing technology provides an attractive fabrication technique, due to its simplicity and low cost. A handful of studies have already demonstrated droplet production through 3D-printed microfluidic devices. However, two

  14. 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...

  15. 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.

  16. 3D-printing of transparent bio-microfluidic devices in PEG-DA.

    Science.gov (United States)

    Urrios, Arturo; Parra-Cabrera, Cesar; Bhattacharjee, Nirveek; Gonzalez-Suarez, Alan M; Rigat-Brugarolas, Luis G; Nallapatti, Umashree; Samitier, Josep; DeForest, Cole A; Posas, Francesc; Garcia-Cordero, José L; Folch, Albert

    2016-06-21

    The vast majority of microfluidic systems are molded in poly(dimethylsiloxane) (PDMS) by soft lithography due to the favorable properties of PDMS: biocompatible, elastomeric, transparent, gas-permeable, inexpensive, and copyright-free. However, PDMS molding involves tedious manual labor, which makes PDMS devices prone to assembly failures and difficult to disseminate to research and clinical settings. Furthermore, the fabrication procedures limit the 3D complexity of the devices to layered designs. Stereolithography (SL), a form of 3D-printing, has recently attracted attention as a way to customize the fabrication of biomedical devices due to its automated, assembly-free 3D fabrication, rapidly decreasing costs, and fast-improving resolution and throughput. However, existing SL resins are not biocompatible and patterning transparent resins at high resolution remains difficult. Here we report procedures for the preparation and patterning of a transparent resin based on low-MW poly(ethylene glycol) diacrylate (MW 250) (PEG-DA-250). The 3D-printed devices are highly transparent and cells can be cultured on PEG-DA-250 prints for several days. This biocompatible SL resin and printing process solves some of the main drawbacks of 3D-printed microfluidic devices: biocompatibility and transparency. In addition, it should also enable the production of non-microfluidic biomedical devices. PMID:27217203

  17. Simulation of magnetic active polymers for versatile microfluidic devices

    CERN Document Server

    Gusenbauer, Markus; Fischbacher, Johann; Reichel, Franz; Exl, Lukas; Bance, Simon; Kataeva, Nadezhda; Binder, Claudia; Brückl, Hubert; Schrefl, Thomas

    2013-01-01

    We propose to use a compound of magnetic nanoparticles (20-100 nm) embedded in a flexible polymer (Polydimethylsiloxane PDMS) to filter circulating tumor cells (CTCs). The analysis of CTCs is an emerging tool for cancer biology research and clinical cancer management including the detection, diagnosis and monitoring of cancer. The combination of experiments and simulations lead to a versatile microfluidic lab-on-chip device. Simulations are essential to understand the influence of the embedded nanoparticles in the elastic PDMS when applying a magnetic gradient field. It combines finite element calculations of the polymer, magnetic simulations of the embedded nanoparticles and the fluid dynamic calculations of blood plasma and blood cells. With the use of magnetic active polymers a wide range of tunable microfluidic structures can be created. The method can help to increase the yield of needed isolated CTCs.

  18. Bubble-induced acoustic mixing in a microfluidic device

    Science.gov (United States)

    Chen, Huaying; Petkovic-Duran, Karolina; Best, Michael; Zhu, Yonggang

    2015-12-01

    Homogeneous and fast mixing of samples at microscale is a critical requirement for successful applications of microfluidics in biochemical analysis, chemical synthesis, drug delivery and nanomaterial synthesis. This paper reports the optimisation of bubble-induced mixing in a microfluidic device in terms of voltage, driving frequency, piezo transducer position and PDMS thickness. The microfluidic device consists of a microwell (with the diameter of 1mm and volume of ~95 nL) with two rectangular bubble traps (400×400μm) on both sides of the well. After the injection of liquid, air bubbles were spontaneously trapped in two rectangular traps. When the frequency of a piezo was equal to the resonance frequency of air bubbles, strong liquid recirculation formed (so called acoustic microstreaming) in the vicinity of the interface of air bubbles and water. The acoustic induced flow of microbeads and mixing of water and fluorescence dye were imaged to study the mixing efficiency. For a given voltage and PDMS thickness, when the piezo was placed on top of the well, the mixing was most vigorous. For a given frequency, the mixing efficiency was directly proportional to the voltage (4-20V) and inversely proportional to the PDMS thickness (0.3-2mm). When the frequency driving the piezo was approaching the resonance frequency of air bubbles, the mixing efficiency was maximal, while when it was far away from the resonance frequency of air bubbles, the mixing efficiency was much lower. This work provides guidance to the design and the application of bubble-induced acoustic mixing in microfluidics.

  19. In search of low cost biological analysis: Wax or acrylic glue bonded paper microfluidic devices

    KAUST Repository

    Kodzius, Rimantas

    2011-01-22

    In this body of work we have been developing and characterizing paper based microfluidic fabrication technologies to produce low cost biological analysis. Specifically we investigated the performance of paper microfluidics that had been bonded using wax or acrylic glue, and characterized the affect of these and other microfluidic materials on the polymerase chain reaction (PCR). We report a simple, low-cost and detachable microfluidic chip incorporating easily accessible paper, glass slides or other polymer films as the chip materials along with adhesive wax or cyanoacrylate-based resin as the recycling bonding material. We use a laser to cut through the paper or film to form patterns and then sandwich the paper and film between glass sheets or polymer membranes. The hot-melt adhesive wax or simple cyanoacrylate-based resin can realize bridge bonding between various materials, for example, paper, polymethylmethacrylate film, glass sheets, or metal plate. The wax bonding process is reversible and the wax is reusable through a melting and cooling process. With this process, a three-dimensional (3D) microfluidic chip is achievable by evacuating the channels of adhesive material in a hot-water. We applied the wax-paper based microfluidic chip to HeLa cell electroporation. Subsequently, a prototype of a 5-layer 3D chip was fabricated by multilayer wax bonding. To check the sealing ability and the durability of the chip, green fluorescence protein recombinant E. coli bacteria were cultured, with which the chemotaxis of E. coli was studied in order to determine the influence of antibiotic ciprofloxacin concentration on the E. coli migration. The chip bonded with cyanoacrylate-based resin was tested by measuring protein concentration and carrying out DNA capillary electrophoresis. To study the biocompatibility and applicability of our microfluidic chip fabrication technology, we tested the PCR compatibility of our chip materials along with various other common materials

  20. Microfluidic devices for investigation of biomimetic membranes for sensor and separation applications

    DEFF Research Database (Denmark)

    Pszon-Bartosz, Kamila Justyna

    drug candidates and in separation technologies, where an exciting example is water purification device based on biomimetic membranes containing aquaporins (highly water selective proteins). However, there are many challenges that must be overcome in order to build biomimetic membrane-based devices...... (up to 6 days) with a bilayer membrane area ~50% of the available aperture area. Highly stable membranes (up to 2 days) with a bilayer membrane area ~24% of the available aperture area were created in the developed microfluidic device. Further, reconstitution of α-hemolysin (α-HL) membrane proteins...

  1. Intracavity Microfluidic Laser Device for Single Cell Analysis

    Science.gov (United States)

    Gourley, Paul

    2015-03-01

    An intracavity microfluidic laser device has been developed to study bioparticles ranging in size from 50 nm to 20 μm (virons to organelles to whole cells). The versatile device can be operated used in several modes including static or flowing fluids, with or without molecular labels, and microscopic imaging and/or spectroscopy. It enables advantageous new ways to perform analyses of bioparticles for applications including cell biology, detection of disease and pathogens, environmental monitoring, pharmaceuticals, agriculture, and food processing. This talk will briefly summarize the physics of the device including its laser optics, fluid dynamics, and intracavity light interaction with cells. The talk will then focus on results of a study of mitochondria in normal and cancer liver cells. The study examines the transformation of intracellular and isolated mitochondria from the normal to disease state. The results highlight the unique utility of the device to rapidly assess biophysical changes arising from altered biomolecular states of cells and organelles.

  2. Fabrication improvements for thermoset polyester (TPE) microfluidic devices.

    Science.gov (United States)

    Fiorini, Gina S; Yim, Moonbin; Jeffries, Gavin D M; Schiro, Perry G; Mutch, Sarah A; Lorenz, Robert M; Chiu, Daniel T

    2007-07-01

    Thermoset polyester (TPE) microfluidic devices were previously developed as an alternative to poly(dimethylsiloxane) (PDMS) devices, fabricated similarly by replica molding, yet offering stable surface properties and good chemical compatibility with some organics that are incompatible with PDMS. This paper describes a number of improvements in the fabrication of TPE chips. Specifically, we describe methods to form TPE devices with a thin bottom layer for use with high numerical aperture (NA) objectives for sensitive fluorescence detection and optical manipulation. We also describe plasma-bonding of TPE to glass to create hybrid TPE-glass devices. We further present a simple master-pretreatment method to replace our original technique that required the use of specialized equipment. PMID:17594014

  3. Development of a PMMA Electrochemical Microfluidic Device for Carcinoembryonic Antigen Detection

    Science.gov (United States)

    Van Anh, Nguyen; Van Trung, Hoang; Tien, Bui Quang; Binh, Nguyen Hai; Ha, Cao Hong; Le Huy, Nguyen; Loc, Nguyen Thai; Thu, Vu Thi; Lam, Tran Dai

    2016-05-01

    In this study, a poly(methyl methacrylate) (PMMA) microfluidic device fabricated by an inexpensive CO2 laser etching system was developed for detection of carcino-embryonic antigens (CEA). The device was capable of working in continuous mode and was designed with the aid of numerical simulation. The detection of target CEA was based on immuno-assay via magnetic particles and electrochemical sensing. The as-prepared microfluidic can be used to detect CEA at the relatively low concentration of 150 pg mL-1. The device could be reused many times, since the capture and removal of magnetic particles in the assay could be manipulated by an external magnetic field. The proposed approach appears to be suitable for high-throughput and automated analysis of large biomolecules such as tumor markers and pathogens.

  4. Mail-order microfluidics: evaluation of stereolithography for the production of microfluidic devices.

    Science.gov (United States)

    Au, Anthony K; Lee, Wonjae; Folch, Albert

    2014-04-01

    The vast majority of microfluidic devices are developed in PDMS by molding ("soft lithography") because PDMS is an inexpensive material, has physicochemical properties that are well suited for biomedical and physical sciences applications, and design cycle lengths are generally adequate for prototype development. However, PDMS molding is tediously slow and thus cannot provide the high- or medium-volume production required for the commercialization of devices. While high-throughput plastic molding techniques (e.g. injection molding) exist, the exorbitant cost of the molds and/or the equipment can be a serious obstacle for device commercialization, especially for small startups. High-volume production is not required to reach niche markets such as clinical trials, biomedical research supplies, customized research equipment, and classroom projects. Crucially, both PDMS and plastic molding are layer-by-layer techniques where each layer is produced as a result of physicochemical processes not specified in the initial photomask(s) and where the final device requires assembly by bonding, all resulting in a cost that is very hard to predict at the start of the project. By contrast, stereolithography (SL) is an automated fabrication technique that allows for the production of quasi-arbitrary 3D shapes in a single polymeric material at medium-volume throughputs (ranging from a single part to hundreds of parts). Importantly, SL devices can be designed between several groups using CAD tools, conveniently ordered by mail, and their cost precisely predicted via a web interface. Here we evaluate the resolution of an SL mail-order service and the main causes of resolution loss; the optical clarity of the devices and how to address the lack of clarity for imaging in the channels; and the future role that SL could play in the commercialization of microfluidic devices.

  5. Quantitative analysis of Caenorhabditis elegans chemotaxis using a microfluidic device.

    Science.gov (United States)

    Hu, Liang; Ye, Jinjuan; Tan, Haowei; Ge, Anle; Tang, Lichun; Feng, Xiaojun; Du, Wei; Liu, Bi-Feng

    2015-08-01

    Caenorhabditis elegans, one of the widely studied model organisms, sense external chemical cues and perform relative chemotaxis behaviors through its simple chemosensory neuronal system. To study the mechanism underlying chemosensory behavior, a rapid and reliable method for quantitatively analyzing the worms' behaviors is essential. In this work, we demonstrated a microfluidic approach for investigating chemotaxis responses of worms to chemical gradients. The flow-based microfluidic chip was consisted of circular tree-like microchannels, which was able to generate eight flow streams containing stepwise chemical concentrations without the difference in flow velocity. Worms' upstream swimming into microchannels with various concentrations was monitored for quantitative analysis of the chemotaxis behavior. By using this microfluidic chip, the attractive and repellent responses of C. elegans to NaCl were successfully quantified within several minutes. The results demonstrated the wild type-like repellent responses and severely impaired attractive responses in grk-2 mutant animals with defects in calcium influx. In addition, the chemotaxis analysis of the third stage larvae revealed that its gustatory response was different from that in the adult stage. Thus, our microfluidic method provided a useful platform for studying the chemosensory behaviors of C. elegans and screening of chemosensation-related chemical drugs. PMID:26320797

  6. Fully Integrated Microfluidic Device for Direct Sample-to-Answer Genetic Analysis

    Science.gov (United States)

    Liu, Robin H.; Grodzinski, Piotr

    Integration of microfluidics technology with DNA microarrays enables building complete sample-to-answer systems that are useful in many applications such as clinic diagnostics. In this chapter, a fully integrated microfluidic device [1] that consists of microfluidic mixers, valves, pumps, channels, chambers, heaters, and a DNA microarray sensor to perform DNA analysis of complex biological sample solutions is present. This device can perform on-chip sample preparation (including magnetic bead-based cell capture, cell preconcentration and purification, and cell lysis) of complex biological sample solutions (such as whole blood), polymerase chain reaction, DNA hybridization, and electrochemical detection. A few novel microfluidic techniques were developed and employed. A micromix-ing technique based on a cavitation microstreaming principle was implemented to enhance target cell capture from whole blood samples using immunomagnetic beads. This technique was also employed to accelerate DNA hybridization reaction. Thermally actuated paraffin-based microvalves were developed to regulate flows. Electrochemical pumps and thermopneumatic pumps were integrated on the chip to provide pumping of liquid solutions. The device is completely self-contained: no external pressure sources, fluid storage, mechanical pumps, or valves are necessary for fluid manipulation, thus eliminating possible sample contamination and simplifying device operation. Pathogenic bacteria detection from ~mL whole blood samples and single-nucleotide polymorphism analysis directly from diluted blood were demonstrated. The device provides a cost-effective solution to direct sample-to-answer genetic analysis, and thus has a potential impact in the fields of point-of-care genetic analysis, environmental testing, and biological warfare agent detection.

  7. An electric stimulation system for electrokinetic particle manipulation in microfluidic devices

    Science.gov (United States)

    Lopez-de la Fuente, M. S.; Moncada-Hernandez, H.; Perez-Gonzalez, V. H.; Lapizco-Encinas, B. H.; Martinez-Chapa, S. O.

    2013-03-01

    Microfluidic devices have grown significantly in the number of applications. Microfabrication techniques have evolved considerably; however, electric stimulation systems for microdevices have not advanced at the same pace. Electric stimulation of micro-fluidic devices is an important element in particle manipulation research. A flexible stimulation instrument is desired to perform configurable, repeatable, automated, and reliable experiments by allowing users to select the stimulation parameters. The instrument presented here is a configurable and programmable stimulation system for electrokinetic-driven microfluidic devices; it consists of a processor, a memory system, and a user interface to deliver several types of waveforms and stimulation patterns. It has been designed to be a flexible, highly configurable, low power instrument capable of delivering sine, triangle, and sawtooth waveforms with one single frequency or two superimposed frequencies ranging from 0.01 Hz to 40 kHz, and an output voltage of up to 30 Vpp. A specific stimulation pattern can be delivered over a single time period or as a sequence of different signals for different time periods. This stimulation system can be applied as a research tool where manipulation of particles suspended in liquid media is involved, such as biology, medicine, environment, embryology, and genetics. This system has the potential to lead to new schemes for laboratory procedures by allowing application specific and user defined electric stimulation. The development of this device is a step towards portable and programmable instrumentation for electric stimulation on electrokinetic-based microfluidic devices, which are meant to be integrated with lab-on-a-chip devices.

  8. Wireless induction heating in a microfluidic device for cell lysis.

    Science.gov (United States)

    Baek, Seung-ki; Min, Junghong; Park, Jung-Hwan

    2010-04-01

    A wireless induction heating system in a microfluidic device was devised for cell lysis to extract DNA and RNA from Escherichia coli. The thermal responses of nickel, iron and copper heating units were studied by applying an alternating magnetic field as a function of geometry of unit, strength of magnetic field, and kind of metal. Heating units were prepared by cutting metal film using a fiber laser, and the units were integrated into a microchannel system using a soft lithographic process. Variation and distribution of temperature on the surface of the heating units was observed using a thermographic camera and temperature labels. The amount of protein released from E. coli by thermal lysis was determined by protein concentration measurement. Hemoglobin released from red blood cells was observed using colorimetric intensity measurement. Extracted DNA was quantified by real-time polymerase chain reaction, and the profile was compared with that of a positive control of ultrasonically disrupted E. coli. The stability of RNA extracted by induction heating was quantified by the measurement of 23S/16S rRNA ratio and comparison with that by normal RNA extraction kit as a gold standard. A solid-shaped nickel structure was selected as the induction heating element in the microfluidic device because of the relatively small influence of geometries and faster thermal response.The amount of protein extracted from E. coli and hemoglobin released from red blood cells by induction heating of the nickel unit in the microfluidic device was proportional to the strength of the applied magnetic field. The lysis of E. coli by induction heating was as effective as lysis of DNA by the ultrasonication method because the threshold cycle values of the sample were compatible with those of the positive control as measured by ultrasonication. Thermal lysis of E. coli by induction heating represents a reasonable alternative to a commercial RNA extraction method as shown by the comparative

  9. Imaging diffusion in a microfluidic device by third harmonic microscopy

    Science.gov (United States)

    Petzold, Uwe; Büchel, Andreas; Hardt, Steffen; Halfmann, Thomas

    2012-09-01

    We monitor and characterize near-surface diffusion of miscible, transparent liquids in a microfluidic device by third harmonic microscopy. The technique enables observations even of transparent or index-matched media without perturbation of the sample. In particular, we image concentrations of ethanol diffusing in water and estimate the diffusion coefficient from the third harmonic images. We obtain a diffusion coefficient D = (460 ± 30) μm2/s, which is consistent with theoretical predictions. The investigations clearly demonstrate the potential of harmonic microscopy also under the challenging conditions of transparent fluids.

  10. Microfluidic device and method for processing of macromolecules

    DEFF Research Database (Denmark)

    2012-01-01

    A microfluidic device and method for enzymatic processing of ultra-long macromolecules is disclosed. The device comprises a reaction chamber with a first manifold, a second manifold, and a plurality of reaction channels, each reaction channel extending from the first manifold to the second manifold....... The device further comprises first inlet and outlet channels for filling the reaction channels via the manifolds with one or more macromolecule containers suspended in a first carrier fluid, wherein the first inlet and outlet channels are configured such that a flow established from the first set of inlets...... to the first set of outlets is guided through the reaction channels, and second inlet and outlet channels for feeding an enzymatic reagent to the reaction chamber essentially without displacing the macromolecule containers trapped in the reaction channels, wherein the second set of inlets and outlets...

  11. Measurements of Elastic Moduli of Silicone Gel Substrates with a Microfluidic Device

    OpenAIRE

    Edgar Gutierrez; Alex Groisman

    2011-01-01

    Thin layers of gels with mechanical properties mimicking animal tissues are widely used to study the rigidity sensing of adherent animal cells and to measure forces applied by cells to their substrate with traction force microscopy. The gels are usually based on polyacrylamide and their elastic modulus is measured with an atomic force microscope (AFM). Here we present a simple microfluidic device that generates high shear stresses in a laminar flow above a gel-coated substrate and apply the d...

  12. Integratable opto-microfluidic devices for sensitive detection of bio-analytes

    OpenAIRE

    Pires, Nuno Miguel Matos

    2014-01-01

    The expensive fabrication of current optical microfluidic devices is a barrier to the successful implementation of these devices in low-cost, high-sensitivity biosensing systems. Organic photodiodes (OPDs) have great potential for application as photodetectors in integrated microfluidic devices due to their uncomplicated optical alignment, thin device architecture, precise control of the active area and simple device fabrication onto glass or polymer substrates. Recent developm...

  13. Miscible Organic Solvents Soak Bonding Method Use in a PMMA Multilayer Microfluidic Device

    Directory of Open Access Journals (Sweden)

    He Zhang

    2014-12-01

    Full Text Available In this paper, we proposed a novel bonding technology to fabricate a microfluidic device based on Poly(methyl methacrylate (PMMA. The method, which used chloroform and ethanol as miscible bonding solvent, can complete complex structures rapid assembly (10 min at 40°C. A bonding strength of 267.5 N/cm2 can be achieved, while the micro channel deformation was less than 7.26%. Then we utilized this method to produce a three layers micro mixer, which included a T-shaped inlet channel and six H-shaped mixing units. Numerical simulation indicated that, the well mixing length of the mixer was only about 6 mm when Re = 10. Finally, fluorescence microscopy was used to verify mixer performance. The method provided the potential for mass production of multilayer rigid polymer microfluidic devices.

  14. Fabrication of Embedded Microvalve on PMMA Microfluidic Devices through Surface Functionalization

    CERN Document Server

    Toh, A G G; Ng, S H

    2008-01-01

    The integration of a PDMS membrane within orthogonally placed PMMA microfluidic channels enables the pneumatic actuation of valves within bonded PMMA-PDMS-PMMA multilayer devices. Here, surface functionalization of PMMA substrates via acid catalyzed hydrolysis and air plasma corona treatment were investigated as possible techniques to permanently bond PMMA microfluidic channels to PDMS surfaces. FTIR and water contact angle analysis of functionalized PMMA substrates showed that air plasma corona treatment was most effective in inducing PMMA hydrophilicity. Subsequent fluidic tests showed that air plasma modified and bonded PMMA multilayer devices could withstand fluid pressure at an operational flow rate of 9 mircoliters/min. The pneumatic actuation of the embedded PDMS membrane was observed through optical microscopy and an electrical resistance based technique. PDMS membrane actuation occurred at pneumatic pressures of as low as 10kPa and complete valving occurred at 14kPa for 100 micrometers x 100 micromet...

  15. Microfluidic Organ/Body-on-a-Chip Devices at the Convergence of Biology and Microengineering

    Directory of Open Access Journals (Sweden)

    Ana Rubina Perestrelo

    2015-12-01

    Full Text Available Recent advances in biomedical technologies are mostly related to the convergence of biology with microengineering. For instance, microfluidic devices are now commonly found in most research centers, clinics and hospitals, contributing to more accurate studies and therapies as powerful tools for drug delivery, monitoring of specific analytes, and medical diagnostics. Most remarkably, integration of cellularized constructs within microengineered platforms has enabled the recapitulation of the physiological and pathological conditions of complex tissues and organs. The so-called “organ-on-a-chip” technology, which represents a new avenue in the field of advanced in vitro models, with the potential to revolutionize current approaches to drug screening and toxicology studies. This review aims to highlight recent advances of microfluidic-based devices towards a body-on-a-chip concept, exploring their technology and broad applications in the biomedical field.

  16. Chemical and physical processes for integrated temperature control in microfluidic devices

    NARCIS (Netherlands)

    Guijt, Rosanne M.; Dodge, Arash; Van Dedem, Gijs W. K.; De Rooij, Nico F.; Verpoorte, Elisabeth

    2003-01-01

    Microfluidic devices are a promising new tool for studying and optimizing (bio)chemical reactions and analyses. Many (bio)chemical reactions require accurate temperature control, such as for example thermocycling for PCR. Here, a new integrated temperature control system for microfluidic devices is

  17. Suspension flow in microfluidic devices - a review of experimental techniques focussing on concentration and velocity gradients

    NARCIS (Netherlands)

    Dinther, van A.M.C.; Schroën, C.G.P.H.; Vergeldt, F.; Sman, van der R.G.M.; Boom, R.M.

    2012-01-01

    Microfluidic devices are an emerging technology for processing suspensions in e.g. medical applications, pharmaceutics and food. Compared to larger scales, particles will be more influenced by migration in microfluidic devices, and this may even be used to facilitate segregation and separation. In o

  18. Microfluidic-based single cell trapping using a combination of stagnation point flow and physical barrier

    Science.gov (United States)

    Yu, Miao; Chen, Zongzheng; Xiang, Cheng; Liu, Bo; Xie, Handi; Qin, Kairong

    2016-06-01

    Single cell trapping in vitro by microfluidic device is an emerging approach for the study of the relationship between single cells and their dynamic biochemical microenvironments. In this paper, a hydrodynamic-based microfluidic device for single cell trapping is designed using a combination of stagnation point flow and physical barrier. The microfluidic device overcomes the weakness of the traditional ones, which have been only based upon either stagnation point flows or physical barriers, and can conveniently load dynamic biochemical signals to the trapped cell. In addition, it can connect with a programmable syringe pump and a microscope to constitute an integrated experimental system. It is experimentally verified that the microfluidic system can trap single cells in vitro even under flow disturbance and conveniently load biochemical signals to the trapped cell. The designed micro-device would provide a simple yet effective experimental platform for further study of the interactions between single cells and their microenvironments.

  19. In search of low cost biological analysis: Wax or acrylic glue bonded paper microfluidic devices

    KAUST Repository

    Kodzius, Rimantas

    2011-11-04

    In this body of work we have been developing and characterizing paper based microfluidic fabrication technologies to produce low cost biological analysis. Specifically we investigated the performance of paper microfluidics that had been bonded using wax o

  20. Low-cost rapid prototyping of flexible microfluidic devices using a desktop digital craft cutter.

    Science.gov (United States)

    Yuen, Po Ki; Goral, Vasiliy N

    2010-02-01

    Low-cost and straight forward rapid prototyping of flexible microfluidic devices using a desktop digital craft cutter is presented. This rapid prototyping method can consistently achieve microchannels as thin as 200 microm in width and can be used to fabricate three-dimensional (3D) microfluidic devices using only double-sided pressure sensitive adhesive (PSA) tape and laser printer transparency film. Various functional microfluidic devices are demonstrated with this rapid prototyping method. The complete fabrication process from device design concept to working device can be completed in minutes without the need of expensive equipment. PMID:20091012

  1. Rapid microfabrication of solvent-resistant biocompatible microfluidic devices.

    Science.gov (United States)

    Hung, Lung-Hsin; Lin, Robert; Lee, Abraham Phillip

    2008-06-01

    This paper presents a rapid, simple, and low-cost fabrication method to prepare solvent resistant and biocompatible microfluidic devices with three-dimensional geometries. The devices were fabricated in thiolene and replicated from PDMS master with high molding fidelity. Good chemical compatibility for organic solvents allows volatile chemicals in synthesis and analysis applications. The surface can be processed to be hydrophobic or hydrophilic for water-in-oil and oil-in-water emulsions. Monodisperse organic solvent droplet generation is demonstrated to be reproducible in thiolene microchannels without swelling. The thiolene surface prevents cell adhesion but normal cell growth and adhesion on glass substrates is not affected by the adjacent thiolene patterns. PMID:18497921

  2. Recent applications of AC electrokinetics in biomolecular analysis on microfluidic devices.

    Science.gov (United States)

    Sasaki, Naoki

    2012-01-01

    AC electrokinetics is a generic term that refers to an induced motion of particles and fluids under nonuniform AC electric fields. The AC electric fields are formed by application of AC voltages to microelectrodes, which can be easily integrated into microfluidic devices by standard microfabrication techniques. Moreover, the magnitude of the motion is large enough to control the mass transfer on the devices. These advantages are attractive for biomolecular analysis on the microfluidic devices, in which the characteristics of small space and microfluidics have been mainly employed. In this review, I describe recent applications of AC electrokinetics in biomolecular analysis on microfluidic devices. The applications include fluid pumping and mixing by AC electrokinetic flow, and manipulation of biomolecules such as DNA and proteins by various AC electrokinetic techniques. Future prospects for highly functional biomolecular analysis on microfluidic devices with the aid of AC electrokinetics are also discussed.

  3. Vapor deposition of cross-linked fluoropolymer barrier coatings onto pre-assembled microfluidic devices.

    Science.gov (United States)

    Riche, Carson T; Marin, Brandon C; Malmstadt, Noah; Gupta, Malancha

    2011-09-21

    The interior surfaces of pre-assembled poly(dimethylsiloxane) (PDMS) microfluidic devices were modified with a cross-linked fluoropolymer barrier coating that significantly increased the chemical compatibility of the devices. PMID:21850298

  4. Rapid prototyping polymers for microfluidic devices and high pressure injections.

    Science.gov (United States)

    Sollier, Elodie; Murray, Coleman; Maoddi, Pietro; Di Carlo, Dino

    2011-11-21

    Multiple methods of fabrication exist for microfluidic devices, with different advantages depending on the end goal of industrial mass production or rapid prototyping for the research laboratory. Polydimethylsiloxane (PDMS) has been the mainstay for rapid prototyping in the academic microfluidics community, because of its low cost, robustness and straightforward fabrication, which are particularly advantageous in the exploratory stages of research. However, despite its many advantages and its broad use in academic laboratories, its low elastic modulus becomes a significant issue for high pressure operation as it leads to a large alteration of channel geometry. Among other consequences, such deformation makes it difficult to accurately predict the flow rates in complex microfluidic networks, change flow speed quickly for applications in stop-flow lithography, or to have predictable inertial focusing positions for cytometry applications where an accurate alignment of the optical system is critical. Recently, other polymers have been identified as complementary to PDMS, with similar fabrication procedures being characteristic of rapid prototyping but with higher rigidity and better resistance to solvents; Thermoset Polyester (TPE), Polyurethane Methacrylate (PUMA) and Norland Adhesive 81 (NOA81). In this review, we assess these different polymer alternatives to PDMS for rapid prototyping, especially in view of high pressure injections with the specific example of inertial flow conditions. These materials are compared to PDMS, for which magnitudes of deformation and dynamic characteristics are also characterized. We provide a complete and systematic analysis of these materials with side-by-side experiments conducted in our lab that also evaluate other properties, such as biocompatibility, solvent compatibility, and ease of fabrication. We emphasize that these polymer alternatives, TPE, PUMA and NOA, have some considerable strengths for rapid prototyping when bond

  5. Graphene-based microfluidics for serial crystallography.

    Science.gov (United States)

    Sui, Shuo; Wang, Yuxi; Kolewe, Kristopher W; Srajer, Vukica; Henning, Robert; Schiffman, Jessica D; Dimitrakopoulos, Christos; Perry, Sarah L

    2016-08-01

    Microfluidic strategies to enable the growth and subsequent serial crystallographic analysis of micro-crystals have the potential to facilitate both structural characterization and dynamic structural studies of protein targets that have been resistant to single-crystal strategies. However, adapting microfluidic crystallization platforms for micro-crystallography requires a dramatic decrease in the overall device thickness. We report a robust strategy for the straightforward incorporation of single-layer graphene into ultra-thin microfluidic devices. This architecture allows for a total material thickness of only ∼1 μm, facilitating on-chip X-ray diffraction analysis while creating a sample environment that is stable against significant water loss over several weeks. We demonstrate excellent signal-to-noise in our X-ray diffraction measurements using a 1.5 μs polychromatic X-ray exposure, and validate our approach via on-chip structure determination using hen egg white lysozyme (HEWL) as a model system. Although this work is focused on the use of graphene for protein crystallography, we anticipate that this technology should find utility in a wide range of both X-ray and other lab on a chip applications. PMID:27241728

  6. Manufacturing microstructured tool inserts for the production of polymeric microfluidic devices

    International Nuclear Information System (INIS)

    Tooling is critical in defining multi-scale patterns for mass production of polymeric microfluidic devices using the microinjection molding process. In the present work, fabrication of various microstructured tool inserts using stainless steel, nickel and bulk metallic glasses (BMGs) is discussed based on die-sinking EDM (electrical discharge machining), electroforming, focused ion beam milling and thermoplastic forming processes. Tool performance is evaluated in terms of surface roughness, hardness and tool life. Compared to stainless steel, nickel and BMGs are capable of integrating length scales from 100 to 10−8 m and are good candidates for producing polymeric microfluidics. Selection of tool materials and manufacturing technologies should consider the end-user requirements of actual applications. (paper)

  7. Combining Electro-Osmotic Flow and FTA® Paper for DNA Analysis on Microfluidic Devices

    Directory of Open Access Journals (Sweden)

    Ryan Wimbles

    2016-07-01

    Full Text Available FTA® paper can be used to protect a variety of biological samples prior to analysis, facilitating ease-of-transport to laboratories or long-term archive storage. The use of FTA® paper as a solid phase eradicates the need to elute the nucleic acids from the matrix prior to DNA amplification, enabling both DNA purification and polymerase chain reaction (PCR-based DNA amplification to be performed in a single chamber on the microfluidic device. A disc of FTA® paper, containing a biological sample, was placed within the microfluidic device on top of wax-encapsulated DNA amplification reagents. The disc containing the biological sample was then cleaned up using Tris-EDTA (TE buffer, which was passed over the disc, via electro-osmotic flow, in order to remove any potential inhibitors of downstream processes. DNA amplification was successfully performed (from buccal cells, whole blood and semen using a Peltier thermal cycling system, whereupon the stored PCR reagents were released during the initial denaturing step due to the wax barrier melting between the FTA® disc and PCR reagents. Such a system offers advantages in terms of a simple sample introduction interface and the ability to process archived samples in an integrated microfluidic environment with minimal risk of contamination.

  8. Investigating the fluid dynamics of rapid processes within microfluidic devices using bright-field microscopy.

    Science.gov (United States)

    Pirbodaghi, Tohid; Vigolo, Daniele; Akbari, Samin; deMello, Andrew

    2015-05-01

    The widespread application of microfluidic devices in the biological and chemical sciences requires the implementation of complex designs and geometries, which in turn leads to atypical fluid dynamic phenomena. Accordingly, a complete understanding of fluid dynamics in such systems is key in the facile engineering of novel and efficient analytical tools. Herein, we present an accurate approach for studying the fluid dynamics of rapid processes within microfluidic devices using bright-field microscopy with white light illumination and a standard high-speed camera. Specifically, we combine Ghost Particle Velocimetry and the detection of moving objects in automated video surveillance to track submicron size tracing particles via cross correlation between the speckle patterns of successive images. The efficacy of the presented technique is demonstrated by measuring the flow field over a square pillar (80 μm × 80 μm) in a 200 μm wide microchannel at high volumetric flow rates. Experimental results are in excellent agreement with those obtained via computational fluid dynamics simulations. The method is subsequently used to study the dynamics of droplet generation at a flow focusing microfluidic geometry. A unique feature of the presented technique is the ability to perform velocimetry analysis of high-speed phenomena, which is not possible using micron-resolution particle image velocimetry (μPIV) approaches based on confocal or fluorescence microscopy. PMID:25812165

  9. Design, production and optimization of solid lipid microparticles (SLM) by a coaxial microfluidic device.

    Science.gov (United States)

    Capretto, Lorenzo; Mazzitelli, Stefania; Nastruzzi, Claudio

    2012-06-28

    This paper describes a method for the production of lipid microparticles (SLM) based on microfluidics using a newly designed modular device constituted of three main parts: a temperature control, a co-flow dripping element and a congealing element. The presented data demonstrated that the microfluidic approach resulted in the production of SLM with narrow size distribution and optimal morphological characteristics in term of sphericity, surface smoothness and absence of defects (i.e. partial coalescence or irregular shape). The optimization of SLM production was performed by screening the effect of different experimental parameters and device configurations by a classical intuitive approach COST (Changing One Separate factor a Time). This process allowed selecting the proper value for a number of parameters including, (i) the congealing element geometry, (ii) the presence and concentration of a stabilizer, (iii) the temperature of water and oil phases and (iv) the water and oil flow rates. In addition, the interplay between oil phase and water phase flow rates, in controlling the size and morphology of SLM, was investigated by a statistical "Design of the Experiments" approach (DoE). The combined use of COST and DoE studies allowed the production of optimized SLM for the encapsulation of dye/drugs. The obtained results demonstrated that the guest molecules did not affect the general characteristics of SLM, confirming the robustness of the microfluidic procedure in view of the production of SLM for biopharmaceutical and biotech protocols. PMID:22542700

  10. Cell-based microfluidic platform for mimicking human olfactory system.

    Science.gov (United States)

    Lee, Seung Hwan; Oh, Eun Hae; Park, Tai Hyun

    2015-12-15

    Various attempts have been made to mimic the human olfactory system using human olfactory receptors (hORs). In particular, OR-expressed cell-based odorant detection systems mimic the smell sensing mechanism of humans, as they exploit endogenous cellular signaling pathways. However, the majority of such cell-based studies have been performed in the liquid phase to maintain cell viability, and liquid odorants were used as detection targets. Here, we present a microfluidic device for the detection of gaseous odorants which more closely mimics the human olfactory system. Cells expressing hOR were cultured on a porous membrane. The membrane was then flipped over and placed between two compartments. The upper compartment is the gaseous part where gaseous odorants are supplied, while the lower compartment is the aqueous part where viable cells are maintained in the liquid medium. Using this simple microfluidic device, we were able to detect gaseous odorant molecules by a fluorescence signal. The fluorescence signal was generated by calcium influx resulting from the interaction between odorant molecules and the hOR. The system allowed detection of gaseous odorant molecules in real-time, and the findings showed that the fluorescence responses increased dose-dependently in the range of 0-2 ppm odorant. In addition, the system can discriminate among gaseous odorant molecules. This microfluidic system closely mimics the human olfactory system in the sense that the submerged cells detect gaseous odorants.

  11. Microwave dielectric heating of fluids in an integrated microfluidic device

    Science.gov (United States)

    Shah, Jayna J.; Sundaresan, Siddarth G.; Geist, Jon; Reyes, Darwin R.; Booth, James C.; Rao, Mulpuri V.; Gaitan, Michael

    2007-11-01

    The ability to selectively and precisely control the temperature of fluid volumes ranging from a few microliters to sub-nanoliters in microfluidic networks is vital for a wide range of applications in micro total analysis systems (μTAS). In this work, we characterize and model the performance of a thin film microwave transmission line integrated with a microfluidic channel to heat fluids with relevant buffer salt concentrations over a wide range of frequencies. A microchannel fabricated in poly(dimethylsiloxane) (PDMS) is aligned with a thin film microwave transmission line in a coplanar waveguide (CPW) configuration. The electromagnetic fields localized in the gap between the signal and ground lines of the transmission line dielectrically heat the fluid in the selected region of the microchannel. Microwave S-parameter measurements and optical fluorescence-based temperature measurements are used with a theoretical model developed based on classical microwave absorption theory to fully characterize the temperature rise of the fluid. We observe a 0.95 °C mW-1 temperature rise at 15 GHz and confirm that the temperature rise of the fluid is predominantly due to microwave dielectric heating.

  12. Mammosphere culture of cancer stem cells in a microfluidic device

    Science.gov (United States)

    Saadin, Katayoon; White, Ian M.

    2012-03-01

    It is known that tumor-initiating cells with stem-like properties will form spherical colonies - termed mammospheres - when cultured in serum-free media on low-attachment substrates. Currently this assay is performed in commercially available 96-well trays with low-attachment surfaces. Here we report a novel microsystem that features on-chip mammosphere culture on low attachment surfaces. We have cultured mammospheres in this microsystem from well-studied human breast cancer cell lines. To enable the long-term culture of these unattached cells, we have integrated diffusion-based delivery columns that provide zero-convection delivery of reagents, such as fresh media, staining agents, or drugs. The multi-layer system consists of parallel cell-culture chambers on top of a low-attachment surface, connected vertically with a microfluidic reagent delivery layer. This design incorporates a reagent reservoir, which is necessary to reduce evaporation from the cell culture micro-chambers. The development of this microsystem will lead to the integration of mammosphere culture with other microfluidic functions, including circulating tumor cell recovery and high throughput drug screening. This will enable the cancer research community to achieve a much greater understanding of these tumor initiating cancer stem cells.

  13. Controlling Nonspecific Protein Adsorption in a Plug-Based Microfluidic System by Controlling Interfacial Chemistry Using Fluorous-Phase Surfactants

    OpenAIRE

    Roach, L. Spencer; Song, Helen; Ismagilov, Rustem F.

    2005-01-01

    Control of surface chemistry and protein adsorption is important for using microfluidic devices for biochemical analysis and high-throughput screening assays. This paper describes the control of protein adsorption at the liquid-liquid interface in a plug-based microfluidic system. The microfluidic system uses multiphase flows of immiscible fluorous and aqueous fluids to form plugs, which are aqueous droplets that are completely surrounded by fluorocarbon oil and do not come into direct contac...

  14. Study of the Chemotactic Response of Multicellular Spheroids in a Microfluidic Device

    OpenAIRE

    Jose M Ayuso; Basheer, Haneen A.; Rosa Monge; Pablo Sánchez-Álvarez; Manuel Doblaré; Shnyder, Steven D.; Victoria Vinader; Kamyar Afarinkia; Luis J Fernández; Ignacio Ochoa

    2015-01-01

    We report the first application of a microfluidic device to observe chemotactic migration in multicellular spheroids. A microfluidic device was designed comprising a central microchamber and two lateral channels through which reagents can be introduced. Multicellular spheroids were embedded in collagen and introduced to the microchamber. A gradient of fetal bovine serum (FBS) was established across the central chamber by addition of growth media containing serum into one of the lateral channe...

  15. Acoustofluidics: theory and simulation of radiation forces at ultrasound resonances in microfluidic devices

    DEFF Research Database (Denmark)

    Barnkob, Rune; Bruus, Henrik

    2009-01-01

    Theoretical analysis is combined with numerical simulations to optimize designs and functionalities of acoustofluidic devices, i.e. microfluidic devices in which ultrasound waves are used to anipulate biological particles. The resonance frequencies and corresponding modes of the acoustic fields...... the largest possible acoustic powers are obtained in the microfluidic system, the time-averaged acoustic radiation force on single particles is determined. Schemes for in situ calibration of this force are presented and discussed....

  16. Fabrication of polystyrene microfluidic devices using a pulsed CO2 laser system

    KAUST Repository

    Li, Huawei

    2013-10-10

    In this article, we described a simple and rapid method for fabrication of droplet microfluidic devices on polystyrene substrate using a CO2 laser system. The effects of the laser power and the cutting speed on the depth, width and aspect ratio of the microchannels fabricated on polystyrene were investigated. The polystyrene microfluidic channels were encapsulated using a hot press bonding technique. The experimental results showed that both discrete droplets and laminar flows could be obtained in the device.

  17. Biofunctionalization of PDMS-based microfluidic systems

    OpenAIRE

    sprotocols

    2015-01-01

    Authors: Bergoi Ibarlucea, Cesar Fernández-Sánchez, Stefanie Demming, Stephanus Büttgenbach & Andreu Llobera ### Abstract Three simple approaches for the selective immobilization of biomolecules on the surface of poly(dimethylsiloxane) (PDMS) microfluidic systems that do not require any specific instrumentation, are described and compared. They are based in the introduction of hydroxyl groups on the PDMS surface by direct adsorption of either polyethylene glycol (PEG) or polyvinyl...

  18. Optofluidic Temperature and Pressure Measurements with Fiber Bragg Gratings Embedded in Microfluidic Devices

    CERN Document Server

    Cooksey, Gregory A

    2016-01-01

    The integration of photonic sensors into microfluidic devices provides opportunities for dynamic measurement of chemical and physical properties of fluids in very small volumes. We previously reported on the use of commercially available Fiber Bragg Gratings (FBGs) and on-chip silicon waveguides for temperature sensing. In this report, we demonstrate the integration of FBGs into easy-to-fabricate microfluidic devices and report on their sensitivity for temperature and pressure measurement in microliter volumes. These sensors present new routes to measurement in microfluidic applications such as small-volume calorimetry and microflow metrology.

  19. Bacterial Response to Antibiotic Gradients in a Porous Microfluidic Device

    Science.gov (United States)

    Deng, J.; Shechtman, L. A.; Sanford, R. A.; Dong, Y.; Werth, C. J.; Fouke, B. W.

    2015-12-01

    Microorganisms in nature have evolved survival strategies to cope with a wide variety of environmental stresses, including gradients in temperature, pH, substrate availability and aqueous chemistry. Microfluidic devices provide a consistently reliable real-time means to quantitatively measure, control and reproduce the dynamic nature of these stresses. As an example, accelerated adaptation from genetic mutations have been observed in E. coli as it responds to gradients of Ciprofloxacin (Zhang et. al. 2011). However, the mechanisms by which bacteria respond to antibiotic gradients, as well as the effect of changes in how the stressor is applied, have not been systematically studied. In this study, newly designed and fabricated microfluidic devices with porous media have been utilized to determine the chemical stress fields that enhance adaptation and thus to test how E. coli bacterial communities adapt to antibiotic stresses. By applying antibiotic and nutrient into inlet channels adjacent to either side of the porous media inoculated with E. coli, a gradient of antibiotic was formed. Hydrogel barriers were selectively photo-polymerized in between of the inlet channels and the porous media to prevent any undesired convection. Hence, chemical solute can only be transported by diffusion, creating a reproducible antibiotic gradient over the porous media. The bacteria were also constrained by the hydrogel boundary barriers from escaping the porous media. Preliminary results suggest that E. coli moves freely with respect to Ciprofloxacin concentrations. In addition, and unexpectedly, the E. coli colonies exhibit a concentric pulsed growth front radiating away from the point of inoculation within the micromodel ecosystem and pulse over the porous media containing antibiotic. The bacteria at the growth front grow into long filaments (up to 100μm) while the bacteria in the inner concentric area are normal size. We hypothesize that the frontier bacteria, which are first

  20. Roll-to-plate fabrication of microfluidic devices with rheology-modified thiol-ene resins

    DEFF Research Database (Denmark)

    Senkbeil, Silja; Aho, Johanna; Yde, Leif;

    2016-01-01

    of 2:1 and a maximal channel depth of 90 μm as well as the sealing of the finished devices with patterning and sealing speeds of up to 19 m min-1. By adding fumed silica nanoparticles to the uncured resins, it was possible to alter the rheological behavior of the resin system to fabricate shallow...... microfluidic channels with 40 × 95 μm cross-sectional dimensions. Moreover, deeper (90 μm) channels can be fabricated with highly viscous resins based on thiol-terminated oligomers. As a demonstration, capillary electrophoresis chips were prepared and tested for a simple separation of two fluorescent dyes....

  1. Preparing mono-dispersed liquid core PDMS microcapsules from thiol–ene–epoxy-tailored flow-focusing microfluidic devices

    DEFF Research Database (Denmark)

    Mazurek, Piotr Stanislaw; Daugaard, Anders Egede; Skolimowski, Maciej;

    2015-01-01

    An applied dual-cure system based on thiol–ene and thiol–epoxy “click chemistry” reactions was proved to be an extremely effective and easy to use tool for preparing microfluidic chips, thereby allowing for precise control over material properties and providing the possibility of covalently bonding...... of compositions in relation to high hydrophilicity and hydrophobicity. An obtained microfluidic device was subsequently used in order to produce PDMS microcapsules of very narrow size distribution and which contained various common liquids, such as water and ethanol, as well as an ionic liquid 2...

  2. Polyimide microfluidic devices with integrated nanoporous filtration areas manufactured by micromachining and ion track technology

    Science.gov (United States)

    Metz, S.; Trautmann, C.; Bertsch, A.; Renaud, Ph

    2004-03-01

    This paper reports on polyimide microfluidic devices fabricated by photolithography and a layer transfer lamination technology. The microchannels are sealed by laminating an uncured polyimide film on a partially cured layer and subsequent imidization. Selected areas of the microchannels were irradiated with heavy ions of several hundred MeV and the generated ion tracks are chemically etched to submicron pores of high aspect ratio. The ion beam parameters and the track etching conditions define density, length, diameter and shape of the pores. Membrane permeability and separation performance is demonstrated in cross-flow filtration experiments. The devices can be used for selective delivery or probing of fluids to biological tissue, e.g. drug delivery or microdialysis. For chip-based devices the filters can be used as a sample pre-treatment unit for filtration or concentration of particles or molecules.

  3. Burn injury reduces neutrophil directional migration speed in microfluidic devices.

    Directory of Open Access Journals (Sweden)

    Kathryn L Butler

    Full Text Available Thermal injury triggers a fulminant inflammatory cascade that heralds shock, end-organ failure, and ultimately sepsis and death. Emerging evidence points to a critical role for the innate immune system, and several studies had documented concurrent impairment in neutrophil chemotaxis with these post-burn inflammatory changes. While a few studies suggest that a link between neutrophil motility and patient mortality might exist, so far, cumbersome assays have prohibited exploration of the prognostic and diagnostic significance of chemotaxis after burn injury. To address this need, we developed a microfluidic device that is simple to operate and allows for precise and robust measurements of chemotaxis speed and persistence characteristics at single-cell resolution. Using this assay, we established a reference set of migration speed values for neutrophils from healthy subjects. Comparisons with samples from burn patients revealed impaired directional migration speed starting as early as 24 hours after burn injury, reaching a minimum at 72-120 hours, correlated to the size of the burn injury and potentially serving as an early indicator for concurrent infections. Further characterization of neutrophil chemotaxis using this new assay may have important diagnostic implications not only for burn patients but also for patients afflicted by other diseases that compromise neutrophil functions.

  4. Thiolene-based microfluidic flow cells for surface plasmon resonance imaging.

    Science.gov (United States)

    Sheppard, Gareth; Oseki, Takao; Baba, Akira; Patton, Derek; Kaneko, Futao; Mao, Leidong; Locklin, Jason

    2011-06-01

    Thiolene-based microfluidic devices have been coupled with surface plasmon resonance imaging (SPRI) to provide an integrated platform to study interfacial interactions in both aqueous and organic solutions. In this work, we develop a photolithographic method that interfaces commercially available thiolene resin to gold and glass substrates to generate microfluidic channels with excellent adhesion that leave the underlying sensor surface free from contamination and readily available for surface modification through self-assembly. These devices can sustain high flow rates and have excellent solvent compatibility even with several organic solvents. To demonstrate the versatility of these devices, we have conducted nanomolar detection of streptavidin-biotin interactions using in situ SPRI.

  5. Investigating Nonalcoholic Fatty Liver Disease in a Liver-on-a-Chip Microfluidic Device

    Science.gov (United States)

    Simonelli, Maria Chiara; Giannitelli, Sara Maria; Businaro, Luca; Trombetta, Marcella; Rainer, Alberto

    2016-01-01

    Background and Aim Nonalcoholic fatty liver disease (NAFLD) is a chronic liver disease worldwide, ranging from simple steatosis to nonalcoholic steatohepatitis, which may progress to cirrhosis, eventually leading to hepatocellular carcinoma (HCC). HCC ranks as the third highest cause of cancer-related death globally, requiring an early diagnosis of NAFLD as a potential risk factor. However, the molecular mechanisms underlying NAFLD are still under investigation. So far, many in vitro studies on NAFLD have been hampered by the limitations of 2D culture systems, in which cells rapidly lose tissue-specific functions. The present liver-on-a-chip approach aims at filling the gap between conventional in vitro models, often scarcely predictive of in vivo conditions, and animal models, potentially biased by their xenogeneic nature. Methods HepG2 cells were cultured into a microfluidically perfused device under free fatty acid (FFA) supplementation, namely palmitic and oleic acid, for 24h and 48h. The device mimicked the endothelial-parenchymal interface of a liver sinusoid, allowing the diffusion of nutrients and removal of waste products similar to the hepatic microvasculature. Assessment of intracellular lipid accumulation, cell viability/cytotoxicity and oxidative stress due to the FFA overload, was performed by high-content analysis methodologies using fluorescence-based functional probes. Results The chip enables gradual and lower intracellular lipid accumulation, higher hepatic cell viability and minimal oxidative stress in microfluidic dynamic vs. 2D static cultures, thus mimicking the chronic condition of steatosis observed in vivo more closely. Conclusions Overall, the liver-on-a-chip system provides a suitable culture microenvironment, representing a more reliable model compared to 2D cultures for investigating NAFLD pathogenesis. Hence, our system is amongst the first in vitro models of human NAFLD developed within a microfluidic device in a sinusoid

  6. A hybrid microfluidic-vacuum device for direct interfacing with conventional cell culture methods

    Directory of Open Access Journals (Sweden)

    Monuki Edwin S

    2007-09-01

    Full Text Available Abstract Background Microfluidics is an enabling technology with a number of advantages over traditional tissue culture methods when precise control of cellular microenvironment is required. However, there are a number of practical and technical limitations that impede wider implementation in routine biomedical research. Specialized equipment and protocols required for fabrication and setting up microfluidic experiments present hurdles for routine use by most biology laboratories. Results We have developed and validated a novel microfluidic device that can directly interface with conventional tissue culture methods to generate and maintain controlled soluble environments in a Petri dish. It incorporates separate sets of fluidic channels and vacuum networks on a single device that allows reversible application of microfluidic gradients onto wet cell culture surfaces. Stable, precise concentration gradients of soluble factors were generated using simple microfluidic channels that were attached to a perfusion system. We successfully demonstrated real-time optical live/dead cell imaging of neural stem cells exposed to a hydrogen peroxide gradient and chemotaxis of metastatic breast cancer cells in a growth factor gradient. Conclusion This paper describes the design and application of a versatile microfluidic device that can directly interface with conventional cell culture methods. This platform provides a simple yet versatile tool for incorporating the advantages of a microfluidic approach to biological assays without changing established tissue culture protocols.

  7. Oxygen Tension and Riboflavin Gradients Cooperatively Regulate the Migration of Shewanella oneidensis MR-1 Revealed by a Hydrogel-Based Microfluidic Device

    Science.gov (United States)

    Kim, Beum Jun; Chu, Injun; Jusuf, Sebastian; Kuo, Tiffany; TerAvest, Michaela A.; Angenent, Largus T.; Wu, Mingming

    2016-01-01

    Shewanella oneidensis is a model bacterial strain for studies of bioelectrochemical systems (BESs). It has two extracellular electron transfer pathways: (1) shuttling electrons via an excreted mediator riboflavin; and (2) direct contact between the c-type cytochromes at the cell membrane and the electrode. Despite the extensive use of S. oneidensis in BESs such as microbial fuel cells and biosensors, many basic microbiology questions about S. oneidensis in the context of BES remain unanswered. Here, we present studies of motility and chemotaxis of S. oneidensis under well controlled concentration gradients of two electron acceptors, oxygen and oxidized form of riboflavin (flavin+), using a newly developed microfluidic platform. Experimental results demonstrate that either oxygen or flavin+ is a chemoattractant to S. oneidensis. The chemotactic tendency of S. oneidensis in a flavin+ concentration gradient is significantly enhanced in an anaerobic in contrast to an aerobic condition. Furthermore, either a low oxygen tension or a high flavin+ concentration considerably enhances the speed of S. oneidensis. This work presents a robust microfluidic platform for generating oxygen and/or flavin+ gradients in an aqueous environment, and demonstrates that two important electron acceptors, oxygen and oxidized riboflavin, cooperatively regulate S. oneidensis migration patterns. The microfluidic tools presented as well as the knowledge gained in this work can be used to guide the future design of BESs for efficient electron production. PMID:27703448

  8. Microfluidic-Based Robotic Sampling System for Radioactive Solutions

    Energy Technology Data Exchange (ETDEWEB)

    Jack D. Law; Julia L. Tripp; Tara E. Smith; Veronica J. Rutledge; Troy G. Garn; John Svoboda; Larry Macaluso

    2014-02-01

    A novel microfluidic based robotic sampling system has been developed for sampling and analysis of liquid solutions in nuclear processes. This system couples the use of a microfluidic sample chip with a robotic system designed to allow remote, automated sampling of process solutions in-cell and facilitates direct coupling of the microfluidic sample chip with analytical instrumentation. This system provides the capability for near real time analysis, reduces analytical waste, and minimizes the potential for personnel exposure associated with traditional sampling methods. A prototype sampling system was designed, built and tested. System testing demonstrated operability of the microfluidic based sample system and identified system modifications to optimize performance.

  9. Microfluidic device for continuous single cells analysis via Raman spectroscopy enhanced by integrated plasmonic nanodimers

    KAUST Repository

    Perozziello, Gerardo

    2015-12-11

    In this work a Raman flow cytometer is presented. It consists of a microfluidic device that takes advantages of the basic principles of Raman spectroscopy and flow cytometry. The microfluidic device integrates calibrated microfluidic channels- where the cells can flow one-by-one -, allowing single cell Raman analysis. The microfluidic channel integrates plasmonic nanodimers in a fluidic trapping region. In this way it is possible to perform Enhanced Raman Spectroscopy on single cell. These allow a label-free analysis, providing information about the biochemical content of membrane and cytoplasm of the each cell. Experiments are performed on red blood cells (RBCs), peripheral blood lymphocytes (PBLs) and myelogenous leukemia tumor cells (K562). © 2015 Optical Society of America.

  10. Grafting of antibodies inside integrated microfluidic-microoptic devices by means of automated microcontact printing

    OpenAIRE

    Bou Chakra, Elie; Hannes, Benjamin; Vieillard, Julien; Mansfield, Colin D.; Mazurczyk, Radoslav; Bouchard, Aude; Potempa, Jan; Krawczyk, Stanislas; Cabrera, Michel

    2009-01-01

    A novel approach to integrating biochip and microfluidic devices is reported in which microcontact printing is a key fabrication technique. The process is performed using an automated microcontact printer that has been developed as an application-specific tool. As proof-of-concept the instrument is used to consecutively and selectively graft patterns of antibodies at the bottom of a glass channel for use in microfluidic immunoassays. Importantly, feature collapse due to over compression of th...

  11. Parallel combinatorial chemical synthesis using single-layer poly(dimethylsiloxane) microfluidic devices

    OpenAIRE

    Dexter, Joseph P.; Parker, William

    2009-01-01

    Improving methods for high-throughput combinatorial chemistry has emerged as a major area of research because of the importance of rapidly synthesizing large numbers of chemical compounds for drug discovery and other applications. In this investigation, a novel microfluidic chip for performing parallel combinatorial chemical synthesis was developed. Unlike past microfluidic systems designed for parallel combinatorial chemistry, the chip is a single-layer device made of poly(dimethylsiloxane) ...

  12. Characterization of Microfluidic Devices by Measurements with μ-PIV and CLSM

    Science.gov (United States)

    Schlter, Michael; Hoffmann, Marko; Rbiger, Norbert

    Microfluidic devices are successfully in use for several applications in chemical engineering and biotechnology. Nevertheless, there is still no breakthrough for microprocess engineering because of a huge lack in understanding of the mechanisms on microscales for momentum transfer, hydrodynamics and mass transfer. Some important questions concern the design of a junction to reach acceptable mixing qualities with minimum pressure drop and narrow residence time distribution even under laminar flow conditions. The micro-particle image velocimetry (μ-PIV) in conjunction with confocal laser scanning microscopy (CLSM) have been used for the characterization of momentum and mass transfer at the Institute of Environmental Process Engineering to evaluate microfluidic devices. The calculation of three-dimensional flow and concentration fields is possible with two-dimensional measurement data for common stationary cases. Streamlines out of velocity gradients and isosurfaces out of fields of the same concentration are providing a helpful impression of the performance of microdevices based on highly reliable measurement data. A quantitative analysis of the velocity and concentration fields allows the calculation of residence-time distribution and mixing quality, which enables the adjustment of microreactor geometries for the demands of chemical, and biochemical reactions.

  13. 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.

  14. Microfluidic-SERS devices for one shot limit-of-detection.

    Science.gov (United States)

    Kim, Donghyuk; Campos, Antonio R; Datt, Ashish; Gao, Zhe; Rycenga, Matthew; Burrows, Nathan D; Greeneltch, Nathan G; Mirkin, Chad A; Murphy, Catherine J; Van Duyne, Richard P; Haynes, Christy L

    2014-07-01

    Microfluidic sensing platforms facilitate parallel, low sample volume detection using various optical signal transduction mechanisms. Herein, we introduce a simple mixing microfluidic device, enabling serial dilution of introduced analyte solution that terminates in five discrete sensing elements. We demonstrate the utility of this device with on-chip fluorescence and surface-enhanced Raman scattering (SERS) detection of analytes, and we demonstrate device use both when combined with a traditional inflexible SERS substrate and with SERS-active nanoparticles that are directly incorporated into microfluidic channels to create a flexible SERS platform. The results indicate, with varying sensitivities, that either flexible or inflexible devices can be easily used to create a calibration curve and perform a limit of detection study with a single experiment. PMID:24756225

  15. Inkjet printing of UV-curable adhesive and dielectric inks for microfluidic devices.

    Science.gov (United States)

    Hamad, E M; Bilatto, S E R; Adly, N Y; Correa, D S; Wolfrum, B; Schöning, M J; Offenhäusser, A; Yakushenko, A

    2016-01-01

    Bonding of polymer-based microfluidics to polymer substrates still poses a challenge for Lab-On-a-Chip applications. Especially, when sensing elements are incorporated, patterned deposition of adhesives with curing at ambient conditions is required. Here, we demonstrate a fabrication method for fully printed microfluidic systems with sensing elements using inkjet and stereolithographic 3D-printing.

  16. Integration of a Novel Microfluidic Device with Silicon Light Emitting Diode-Antifuse and Photodetector

    NARCIS (Netherlands)

    LeMinh, P.; Holleman, J.; Berenschot, J.W.; Tas, N.R.; Berg, van den A.

    2002-01-01

    Light emitting diode antifuse has been integrated into a microfluidic device that is realized with extended standard CMOS technological steps. The device comprises of a microchannel sandwiched between a photodiode detector and a nanometer-scale diode antifuse light emitter. In this chapter, the devi

  17. Monolithic Integration of a Novel Microfluidic Device with Silicon Light Emitting Diode-Antifuse and Photodetector

    NARCIS (Netherlands)

    LeMinh, P.; Holleman, J.; Berenschot, J.W.; Tas, N.R.; Berg, van den A.

    2002-01-01

    Light emitting diode antifuse has been integrated into a microfluidic device that is realized with extended standard CMOS technological steps. The device comprises of a microchannel sandwiched between a photodiode detector and a nanometer-scale diode antifuse light emitter. Within this contribution,

  18. Note: A microfluidic freezer based on evaporative cooling of atomized aqueous microdroplets

    Energy Technology Data Exchange (ETDEWEB)

    Song, Jin; Kim, Dohyun, E-mail: dohyun.kim@mju.ac.kr [Department of Mechanical Engineering, Myongji University, Yongin-si, Gyeonggi-do 449-728 (Korea, Republic of); Chung, Minsub [Department of Chemical Engineering, Hongik University, Mapo-gu, Seoul 121-791 (Korea, Republic of)

    2015-01-15

    We report for the first time water-based evaporative cooling integrated into a microfluidic chip for temperature control and freezing of biological solution. We opt for water as a nontoxic, effective refrigerant. Aqueous solutions are atomized in our device and evaporation of microdroplets under vacuum removes heat effectively. We achieve rapid cooling (−5.1 °C/s) and a low freezing temperature (−14.1 °C). Using this approach, we demonstrate freezing of deionized water and protein solution. Our simple, yet effective cooling device may improve many microfluidic applications currently relying on external power-hungry instruments for cooling and freezing.

  19. Portable audio electronics for impedance-based measurements in microfluidics

    International Nuclear Information System (INIS)

    We demonstrate the use of audio electronics-based signals to perform on-chip electrochemical measurements. Cell phones and portable music players are examples of consumer electronics that are easily operated and are ubiquitous worldwide. Audio output (play) and input (record) signals are voltage based and contain frequency and amplitude information. A cell phone, laptop soundcard and two compact audio players are compared with respect to frequency response; the laptop soundcard provides the most uniform frequency response, while the cell phone performance is found to be insufficient. The audio signals in the common portable music players and laptop soundcard operate in the range of 20 Hz to 20 kHz and are found to be applicable, as voltage input and output signals, to impedance-based electrochemical measurements in microfluidic systems. Validated impedance-based measurements of concentration (0.1–50 mM), flow rate (2–120 µL min−1) and particle detection (32 µm diameter) are demonstrated. The prevailing, lossless, wave audio file format is found to be suitable for data transmission to and from external sources, such as a centralized lab, and the cost of all hardware (in addition to audio devices) is ∼10 USD. The utility demonstrated here, in combination with the ubiquitous nature of portable audio electronics, presents new opportunities for impedance-based measurements in portable microfluidic systems. (technical note)

  20. Fabrication of 3D Microfluidic Devices by Thermal Bonding of Thin Poly(methyl methacrylate) Films

    KAUST Repository

    Perez, Paul

    2012-07-01

    The use of thin-film techniques for the fabrication of microfluidic devices has gained attention over the last decade, particularly for three-dimensional channel structures. The reasons for this include effective use of chip volume, mechanical flexibility, dead volume reduction, enhanced design capabilities, integration of passive elements, and scalability. Several fabrication techniques have been adapted for use on thin films: laser ablation and hot embossing are popular for channel fabrication, and lamination is widely used for channel enclosure. However, none of the previous studies have been able to achieve a strong bond that is reliable under moderate positive pressures. The present work aims to develop a thin-film process that provides design versatility, speed, channel profile homogeneity, and the reliability that others fail to achieve. The three building blocks of the proposed baseline were fifty-micron poly(methyl methacrylate) thin films as substrates, channel patterning by laser ablation, and device assembly by thermal-fusion bonding. Channel fabrication was characterized and tuned to produce the desired dimensions and surface roughness. Thermal bonding was performed using an adapted mechanical testing device and optimized to produce the maximum bonding strength without significant channel deformation. Bonding multilayered devices, incorporating conduction lines, and integrating various types of membranes as passive elements demonstrated the versatility of the process. Finally, this baseline was used to fabricate a droplet generator and a DNA detection chip based on micro-bead agglomeration. It was found that a combination of low laser power and scanning speed produced channel surfaces with better uniformity than those obtained with higher values. In addition, the implemented bonding technique provided the process with the most reliable bond strength reported, so far, for thin-film microfluidics. Overall, the present work proved to be versatile

  1. A microfluidic AFM cantilever based dispensing and aspiration platform

    NARCIS (Netherlands)

    Van Oorschot, R.; Perez Garza, H.H.; Derks, R.J.S.; Staufer, U.; Ghatkesar, M.K.

    2015-01-01

    We present the development of a microfluidic AFM (atomic force microscope) cantilever-based platform to enable the local dispensing and aspiration of liquid with volumes in the pico-to-femtoliter range. The platform consists of a basic AFM measurement system, microfluidic AFM chip, fluidic interface

  2. Latex immunoagglutination assay for bovine viral diarrhea virus utilizing forward light scattering in a microfluidic device

    Science.gov (United States)

    Heinze, Brian C.; Song, Jae-Young; Han, Jin-Hee; Yoon, Jeong-Yeol

    2008-02-01

    We have investigated the utilization of particle agglutination assays using forward light scattering measurements in a microfluidic device towards detecting viral particles. The model viral target was bovine viral diarrhea virus (BVDV). Highly carboxylated polystyrene microspheres (510 nm) were coated with anti-BVDV monoclonal antibodies. This solution was in turn used to detect live modified BVDV. This assay was first performed in a two well slide for proof of concept and then in a simple y-channel microfluidic device with optical fibers arranged in a close proximity setup. Particle immunoagglutination was detected through static light scattering measurements taken at 45° to incident light. In the microfluidic device, modified live BVDV was detected with a detection limit of 0.5 TCID 50 mL -1.

  3. A microfluidic paper-based electrochemical biosensor array for multiplexed detection of metabolic biomarkers

    Directory of Open Access Journals (Sweden)

    Chen Zhao, Martin M Thuo and Xinyu Liu

    2013-01-01

    Full Text Available Paper-based microfluidic devices have emerged as simple yet powerful platforms for performing low-cost analytical tests. This paper reports a microfluidic paper-based electrochemical biosensor array for multiplexed detection of physiologically relevant metabolic biomarkers. Different from existing paper-based electrochemical devices, our device includes an array of eight electrochemical sensors and utilizes a handheld custom-made electrochemical reader (potentiostat for signal readout. The biosensor array can detect several analytes in a sample solution and produce multiple measurements for each analyte from a single run. Using the device, we demonstrate simultaneous detection of glucose, lactate and uric acid in urine, with analytical performance comparable to that of the existing commercial and paper-based platforms. The paper-based biosensor array and its electrochemical reader will enable the acquisition of high-density, statistically meaningful diagnostic information at the point of care in a rapid and cost-efficient way.

  4. A microfluidic paper-based electrochemical biosensor array for multiplexed detection of metabolic biomarkers

    Science.gov (United States)

    Zhao, Chen; Thuo, Martin M.; Liu, Xinyu

    2013-10-01

    Paper-based microfluidic devices have emerged as simple yet powerful platforms for performing low-cost analytical tests. This paper reports a microfluidic paper-based electrochemical biosensor array for multiplexed detection of physiologically relevant metabolic biomarkers. Different from existing paper-based electrochemical devices, our device includes an array of eight electrochemical sensors and utilizes a handheld custom-made electrochemical reader (potentiostat) for signal readout. The biosensor array can detect several analytes in a sample solution and produce multiple measurements for each analyte from a single run. Using the device, we demonstrate simultaneous detection of glucose, lactate and uric acid in urine, with analytical performance comparable to that of the existing commercial and paper-based platforms. The paper-based biosensor array and its electrochemical reader will enable the acquisition of high-density, statistically meaningful diagnostic information at the point of care in a rapid and cost-efficient way.

  5. Time lapse investigation of antibiotic susceptibility using a microfluidic linear gradient 3D culture device.

    Science.gov (United States)

    Hou, Zining; An, Yu; Hjort, Karin; Hjort, Klas; Sandegren, Linus; Wu, Zhigang

    2014-09-01

    This study reports a novel approach to quantitatively investigate the antibacterial effect of antibiotics on bacteria using a three-dimensional microfluidic culture device. In particular, our approach is suitable for studying the pharmacodynamics effects of antibiotics on bacterial cells temporally and with a continuous range of concentrations in a single experiment. The responses of bacterial cells to a linear concentration gradient of antibiotics were observed using time-lapse photography, by encapsulating bacterial cells in an agarose-based gel located in a commercially available microfluidics chamber. This approach generates dynamic information with high resolution, in a single operation, e.g., growth curves and antibiotic pharmacodynamics, in a well-controlled environment. No pre-labelling of the cells is needed and therefore any bacterial sample can be tested in this setup. It also provides static information comparable to that of standard techniques for measuring minimum inhibitory concentration (MIC). Five antibiotics with different mechanisms were analysed against wild-type Escherichia coli, Staphylococcus aureus and Salmonella Typhimurium. The entire process, including data analysis, took 2.5-4 h and from the same analysis, high-resolution growth curves were obtained. As a proof of principle, a pharmacodynamic model of streptomycin against Salmonella Typhimurium was built based on the maximal effect model, which agreed well with the experimental results. Our approach has the potential to be a simple and flexible solution to study responding behaviours of microbial cells under different selection pressures both temporally and in a range of concentrations.

  6. Microfluidic transport of photopolymerizable species for laser source integration in lab-on-a-chip photonic devices

    Science.gov (United States)

    Lucchetta, D. E.; Castagna, R.; Vita, F.; Gianni, A.; Simoni, F.

    2012-10-01

    We recently developed a novel composite photopolymerizable material which allows the holographic recording of diffraction gratings with optimal optical and mechanical properties (high diffraction efficiency, transparency and spatial resolution, low shrinkage, long time stability). This material was successfully used to produce a low cost and easy to make optically pumped, organic distributed feedback laser, working on the first diffraction order of a high quality Bragg grating doped with a photoluminescent dye. Here we show the possibility of positioning these micrometer sized light sources at any point of a generic lab-on-a-chip device by borrowing experimental techniques commonly used in the fields of microfluidics and optofluidics. In particular, a microfluidic channel has been imprinted by soft lithography in a polydimethylsiloxane substrate in order to convey the photopolymerizable mixture to a particular area of the sample, where the laser device has been holographically recorded. A characterization of the lasing properties of this device has been carried out. The proposed approach allows a better confinement of the emitted light and overcomes some physical constrains (resolution, aspect ratio) of PDMS based microfluidic laser thus opening new possibilities for the complex integration of organic laser sources in lab-on-a-chip devices.

  7. Metaphase FISH on a Chip: Miniaturized Microfluidic Device for Fluorescence in situ Hybridization

    Directory of Open Access Journals (Sweden)

    Niels Tommerup

    2010-11-01

    Full Text Available Fluorescence in situ Hybridization (FISH is a major cytogenetic technique for clinical genetic diagnosis of both inherited and acquired chromosomal abnormalities. Although FISH techniques have evolved and are often used together with other cytogenetic methods like CGH, PRINS and PNA-FISH, the process continues to be a manual, labour intensive, expensive and time consuming technique, often taking over 3–5 days, even in dedicated labs. We have developed a novel microFISH device to perform metaphase FISH on a chip which overcomes many shortcomings of the current laboratory protocols. This work also introduces a novel splashing device for preparing metaphase spreads on a microscope glass slide, followed by a rapid adhesive tape-based bonding protocol leading to rapid fabrication of the microFISH device. The microFISH device allows for an optimized metaphase FISH protocol on a chip with over a 20-fold reduction in the reagent volume. This is the first demonstration of metaphase FISH on a microfluidic device and offers a possibility of automation and significant cost reduction of many routine diagnostic tests of genetic anomalies.

  8. Field-effect flow control in a polydimethylsiloxane-based microfluidic system.

    Science.gov (United States)

    Buch, J S; Wang, P C; DeVoe, D L; Lee, C S

    2001-10-01

    The application of the field-effect for direct control of electroosmosis in a polydimethylsiloxane (PDMS)-based microfluidic system, constructed on a silicon wafer with a 2.0 microm electrically insulating layer of silicon dioxide, is demonstrated. This microfluidic system consists of a 2.0 cm open microchannel fabricated on a PDMS slab, which can reversibly adhere to the silicon wafer to form a hybrid microfluidic device. Aside from mechanically serving as a robust bottom substrate to seal the channel and support the microfluidic system, the silicon wafer is exploited to achieve field-effect flow control by grounding the semiconductive silicon medium. When an electric field is applied through the channel, a radial electric potential gradient is created across the silicon dioxide layer that allows for direct control of the zeta potential and the resulting electroosmotic flow (EOF). By configuring this microfluidic system with two power supplies at both ends of the microchannel, the applied electric potentials can be varied for manipulating the polarity and the magnitude of the radial electric potential gradient across the silicon dioxide layer. At the same time, the longitudinal potential gradient through the microchannel, which is used to induce EOF, is held constant. The results of EOF control in this hybrid microfluidic system are presented for phosphate buffer at pH 3 and pH 5. It is also demonstrated that EOF control can be performed at higher solution pH of 6 and 7.4 by modifying the silicon wafer surface with cetyltrimethylammonium bromide (CTAB) prior to assembly of the hybrid microfluidic system. Results of EOF control from this study are compared with those reported in the literature involving the use of other microfluidic devices under comparable solution conditions. PMID:11700719

  9. QR-on-a-chip: a computer-recognizable micro-pattern engraved microfluidic device for high-throughput image acquisition.

    Science.gov (United States)

    Yun, Kyungwon; Lee, Hyunjae; Bang, Hyunwoo; Jeon, Noo Li

    2016-02-21

    This study proposes a novel way to achieve high-throughput image acquisition based on a computer-recognizable micro-pattern implemented on a microfluidic device. We integrated the QR code, a two-dimensional barcode system, onto the microfluidic device to simplify imaging of multiple ROIs (regions of interest). A standard QR code pattern was modified to arrays of cylindrical structures of polydimethylsiloxane (PDMS). Utilizing the recognition of the micro-pattern, the proposed system enables: (1) device identification, which allows referencing additional information of the device, such as device imaging sequences or the ROIs and (2) composing a coordinate system for an arbitrarily located microfluidic device with respect to the stage. Based on these functionalities, the proposed method performs one-step high-throughput imaging for data acquisition in microfluidic devices without further manual exploration and locating of the desired ROIs. In our experience, the proposed method significantly reduced the time for the preparation of an acquisition. We expect that the method will innovatively improve the prototype device data acquisition and analysis. PMID:26728124

  10. An inkjet-printed microfluidic device for liquid-liquid extraction.

    Science.gov (United States)

    Watanabe, Masashi

    2011-04-01

    A microfluidic device for liquid-liquid extraction was quickly produced using an office inkjet printer. An advantage of this method is that normal end users, who are not familiar with microfabrication, can produce their original microfluidic devices by themselves. In this method, the printer draws a line on a hydrophobic and oil repellent surface using hydrophilic ink. This line directs a fluid, such as water or xylene, to form a microchannel along the printed line. Using such channels, liquid-liquid extraction was successfully performed under concurrent and countercurrent flow conditions.

  11. The effects of heat treatment on microfluidic devices fabricated in silica glass by femtosecond lasers

    Institute of Scientific and Technical Information of China (English)

    Li Yan; Qu Shi-Liang

    2012-01-01

    We fabricated complex microfluidic devices in silica glass by water-assisted femtosecond laser ablation and sub-sequent heat treatment.The experimental results show that after heat treatment,the diameter of the microchannels is significantly reduced and the internal surface roughness is improved.The diameters of the fabricated microchannels can be modulated by changing the annealing temperature and the annealing time.During annealing,the temperature affects the diameter and shape of the protrusions in microfluidic devices very strongly,and these changes are mainly caused by uniform expansion and the action of surface tension.

  12. Microfluidic Device to Quantify the Behavior of Therapeutic Bacteria in Three-Dimensional Tumor Tissue

    Science.gov (United States)

    Brackett, Emily L.; Swofford, Charles A.; Forbes, Neil S.

    2016-01-01

    Summary Microfluidic devices enable precise quantification of the interactions between anticancer bacteria and tumor tissue. Direct observation of bacterial movement and gene expression in tissue is not possible with either monolayers of cells or tumor-bearing mice. Quantification of these interactions is necessary to understand the inherent mechanisms of bacterial targeting and to develop modified organisms with enhanced therapeutic properties. Here we describe the procedures for designing, printing and assembling microfluidic tumor-on-a-chip devices. We also describe the procedures for inserting three- dimensional tumor-cell masses, exposing to bacteria, and analyzing the resultant images. PMID:26846800

  13. Product qualification: a barrier to point-of-care microfluidic-based diagnostics?

    Science.gov (United States)

    Tantra, Ratna; van Heeren, Henne

    2013-06-21

    One of the most exciting applications of microfluidics-based diagnostics is its potential use in next generation point-of-care (POC) devices. Many prototypes are already in existence, but, as of yet, few have achieved commercialisation. In this article, we consider the issue surrounding product qualification as a potential barrier to market success. The study discusses, in the context of POC microfluidics-based diagnostics, what the generic issues are and potential solutions. Our findings underline the need for a community-based effort that is necessary to speed up the product qualification process. PMID:23652789

  14. A Laminated Microfluidic Device for Comprehensive Preclinical Testing in the Drug ADME Process

    OpenAIRE

    Fan An; Yueyang Qu; Yong Luo; Ning Fang; Yang Liu; Zhigang Gao; Weijie Zhao; Bingcheng Lin

    2016-01-01

    New techniques are urgently needed to replace conventional long and costly pre-clinical testing in the new drug administration process. In this study, a laminated microfluidic device was fabricated to mimic the drug ADME response test in vivo. This proposed device was loaded and cultured with functional cells for drug response investigation and organ tissues that are involved in ADME testing. The drug was introduced from the top of the device and first absorbed by the Caco-2 cell layer, and t...

  15. Microfluidic-optical integrated CMOS compatible devices for label-free biochemical sensing

    Science.gov (United States)

    Blanco, F. J.; Agirregabiria, M.; Berganzo, J.; Mayora, K.; Elizalde, J.; Calle, A.; Dominguez, C.; Lechuga, L. M.

    2006-05-01

    The fabrication, characterization and packaging of novel microfluidic-optical integrated biosensors for label-free biochemical detection is presented in this paper. The integrated device consists of a three-dimensional embedded microchannel network fabricated using enhanced CMOS compatible SU-8 multilevel polymer technology on top of a wafer containing Mach-Zehnder Interferometer (MZI) nanophotonic biosensor devices. PMMA housing provides connection to the macro-world and ensures robust leakage-free flow operation of the devices. This macro-microfluidic module can operate at pressure drops up to 1000 kPa. Fluid flow experiments have been performed in order to demonstrate the robustness of our microfluidic devices. The devices have been designed to operate under continuous flow. Steady-state flow rates ranging from 1 to 100 µl min-1 at pressure drops ranging from 10 to 500 kPa were measured in the laminar flow regime. Experimental results are in good agreement with laminar flow theory. The first interferometric sensing measurements are presented in order to demonstrate the functionality of these novel integrated devices for lab-on-a-chip and label-free biosensing applications. A bulk refractive index detection limit of 3.8 × 10-6 was obtained, close to the minimum detected up to now by label-free biosensor devices without microfluidic integration. As far as we know, this is the first time that a label-free biosensor device is integrated within a microfluidic network using a wafer-level CMOS compatible process technology.

  16. Microfluidic System for Solution Array Based Bioassays

    Energy Technology Data Exchange (ETDEWEB)

    Dougherty, G M; Tok, J B; Pannu, S S; Rose, K A

    2006-02-10

    The objective of this project is to demonstrate new enabling technology for multiplex biodetection systems that are flexible, miniaturizable, highly automated, low cost, and high performance. It builds on prior successes at LLNL with particle-based solution arrays, such as those used in the Autonomous Pathogen Detection System (APDS) successfully field deployed to multiple locations nationwide. We report the development of a multiplex solution array immunoassay based upon engineered metallic nanorod particles. Nanobarcodes{reg_sign} particles are fabricated by sequential electrodeposition of dissimilar metals within porous alumina templates, yielding optically encoded striping patterns that can be read using standard laboratory microscope optics and PC-based image processing software. The addition of self-assembled monolayer (SAM) coatings and target-specific antibodies allows each encoded class of nanorod particles to be directed against a different antigen target. A prototype assay panel directed against bacterial, viral, and soluble protein targets demonstrates simultaneous detection at sensitivities comparable to state of the art immunoassays, with minimal cross-reactivity. Studies have been performed to characterize the colloidal properties (zeta potential) of the suspended nanorod particles as a function of pH, the ionic strength of the suspending solution, and surface functionalization state. Additional studies have produced means for the non-contact manipulation of the particles, including the insertion of magnetic nickel stripes within the encoding pattern, and control via externally applied electromagnetic fields. Using the results of these studies, the novel Nanobarcodes{reg_sign} based assay was implemented in a prototype automated system with the sample processing functions and optical readout performed on a microfluidic card. The unique physical properties of the nanorod particles enable the development of integrated microfluidic systems for

  17. A Microfluidic Device with Integrated Sonication and Immunoprecipitation for Sensitive Epigenetic Assays.

    Science.gov (United States)

    Cao, Zhenning; Lu, Chang

    2016-02-01

    Epigenetic studies increasingly require analysis of a small number of cells that are of one specific type and derived from patients or animals. In this report, we demonstrate a simple microfluidic device that integrates sonication and immunoprecipitation (IP) for epigenetic assays, such as chromatin immunoprecipitation (ChIP) and methylated DNA immunoprecipitation (MeDIP). By incorporating an ultrasonic transducer with a microfluidic chamber, we implemented microscale sonication for both shearing chromatin/DNA and mixing/washing of IP beads. Such integration allowed highly sensitive tests starting with 100 cross-linked cells for ChIP or 500 pg of genomic DNA for MeDIP (compared to 10(6)-10(7) cells for ChIP and 1-10 μg of DNA for MeDIP in conventional assays). The entire on-chip process of sonication and IP took only 1 h. Our tool will be useful for highly sensitive epigenetic studies based on a small quantity of sample.

  18. Fabrication and Characterization of a Microfluidic Device to Ultrapurify Blood Samples

    KAUST Repository

    Tallerico, Marco

    2015-05-04

    The improvement of blood cell sorting techniques in recent years have attracted the attention of many researchers due to the possible benefits that these methods can lead in biology, regenerative medicine, materials science and therapeutic area. In this work a cell sorting technique based on filtration is described. The separation occurs by means of a microfluidic device, suitably designed, manufactured and tested, that is connected to an external experimental set-up. The fabrication process can be divided in two parts: at first it is described the manufacturing process of a filtering membrane, with holes of specific size that allow the passage of only certain cell types. Following the microfluidic device is fabricated through the mechanical micromilling. The membrane and the microdevice are suitably bonded and tested by means of an external connection with syringe pumps that inject blood samples at specific flow rates. The device is designed to separate blood cells and tumor cells only by using differences in size and shape. In particular during the first experiments red blood cells and platelets are sorted from white blood cells; in the other experiments red blood cells and platelets are separated from white blood cells and tumor cells. The microdevice has proven to be very efficient, in fact a capture efficiency of 99% is achieved. For this reason it could be used in identification and isolation of circulating tumor cells, a very rare cancer cell type whose presence in the bloodstream could be symptom of future solid tumor formation. The various experiments have also demonstrated that tumor cells survive even after the separation treatment, and then the suffered stress during the sorting process does not harm the biological sample.

  19. Comparison of production methods of a spiral inertial microfluidic cell separation device

    Science.gov (United States)

    Robinson, Mitchell; Marks, Haley; Coté, Gerard L.

    2016-03-01

    From the miniaturization of large sample processing machines to the creation of handheld point-of-care devices, microfluidics has the potential to be a powerful tool in the advancement of diagnostic technologies. Here, we compare different prototyping modalities towards the generation of an inertial microfluidic blood filter: i.e. a 'centrifuge-on-a-chip'. While photolithography is currently the method of choice for soft lithography mold fabrication, offering high design fidelity, we believe simpler methods, such as milling or 3D printing, will soon become equally viable options in the field of microfluidic device fabrication. Three modalities for optofluidic PDMS chip fabrication were compared: micromachining, 3D printing, and SU8 photolithography. The filtration efficiency of the chips were tested with whole blood and compared spectroscopically by monitoring the outlet absorbance at the 540 nm peak intrinsic to oxyhemoglobin at the outlet of each filter chip.

  20. Large-Scale Integration of All-Glass Valves on a Microfluidic Device

    Directory of Open Access Journals (Sweden)

    Yaxiaer Yalikun

    2016-05-01

    Full Text Available In this study, we developed a method for fabricating a microfluidic device with integrated large-scale all-glass valves and constructed an actuator system to control each of the valves on the device. Such a microfluidic device has advantages that allow its use in various fields, including physical, chemical, and biochemical analyses and syntheses. However, it is inefficient and difficult to integrate the large-scale all-glass valves in a microfluidic device using conventional glass fabrication methods, especially for the through-hole fabrication step. Therefore, we have developed a fabrication method for the large-scale integration of all-glass valves in a microfluidic device that contains 110 individually controllable diaphragm valve units on a 30 mm × 70 mm glass slide. This prototype device was fabricated by first sandwiching a 0.4-mm-thick glass slide that contained 110 1.5-mm-diameter shallow chambers, each with two 50-μm-diameter through-holes, between an ultra-thin glass sheet (4 μm thick and another 0.7-mm-thick glass slide that contained etched channels. After the fusion bonding of these three layers, the large-scale microfluidic device was obtained with integrated all-glass valves consisting of 110 individual diaphragm valve units. We demonstrated its use as a pump capable of generating a flow rate of approximately 0.06–5.33 μL/min. The maximum frequency of flow switching was approximately 12 Hz.

  1. Origin of periodic and chaotic dynamics due to drops moving in a microfluidic loop device.

    Science.gov (United States)

    Maddala, Jeevan; Vanapalli, Siva A; Rengaswamy, Raghunathan

    2014-02-01

    Droplets moving in a microfluidic loop device exhibit both periodic and chaotic behaviors based on the inlet droplet spacing. We observe that the periodic behavior is an outcome of carrier phase mass conservation principle, which translates into a droplet spacing quantization rule. This rule implies that the summation of exit spacing is equal to an integral multiple of inlet spacing. This principle also enables identification of periodicity in experimental systems with input scatter. We find that the origin of chaotic behavior is through intermittency, which arises when drops enter and leave the junctions at the same time. We derive an analytical expression to estimate the occurrence of these chaotic regions as a function of system parameters. We provide experimental, simulation, and analytical results to validate the origin of periodic and chaotic behavior.

  2. Scintillation Particle Detectors Based on Plastic Optical Fibres and Microfluidics

    CERN Document Server

    Mapelli, Alessandro; Renaud, Philippe

    2011-01-01

    This thesis presents the design, development, and experimental validation of two types of scintillation particle detectors with high spatial resolution. The first one is based on the well established scintillating fibre technology. It will complement the ATLAS (A Toroidal Large ApparatuS) detector at the CERN Large Hadron Collider (LHC). The second detector consists in a microfabricated device used to demonstrate the principle of operation of a novel type of scintillation detector based on microfluidics. The first part of the thesis presents the work performed on a scintillating fibre tracking system for the ATLAS experiment. It will measure the trajectory of protons elastically scattered at very small angles to determine the absolute luminosity of the CERN LHC collider at the ATLAS interaction point. The luminosity of an accelerator characterizes its performance. It is a process-independent parameter that is completely determined by the properties of the colliding beams and it relates the cross section of a ...

  3. 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

  4. Development of a microfluidic device for cell concentration and blood cell-plasma separation.

    Science.gov (United States)

    Maria, M Sneha; Kumar, B S; Chandra, T S; Sen, A K

    2015-12-01

    This work presents design, fabrication and test of a microfluidic device which employs Fahraeus-Lindqvist and Zweifach-Fung effects for cell concentration and blood cell-plasma separation. The device design comprises a straight main channel with a series of branched channels placed symmetrically on both sides of the main channel. The design implements constrictions before each junction (branching point) in order to direct cells that would have migrated closer to the wall (naturally or after liquid extraction at a junction) towards the centre of the main channel. Theoretical and numerical analysis are performed for design of the microchannel network to ensure that a minimum flow rate ratio (of 2.5:1, main channel-to-side channels) is maintained at each junction and predict flow rate at the plasma outlet. The dimensions and location of the constrictions were determined using numerical simulations. The effect of presence of constrictions before the junctions was demonstrated by comparing the performances of the device with and without constrictions. To demonstrate the performance of the device, initial experiments were performed with polystyrene microbeads (10 and 15 μm size) and droplets. Finally, the device was used for concentration of HL60 cells and separation of plasma and cells in diluted blood samples. The cell concentration and blood-plasma purification efficiency was quantified using Haemocytometer and Fluorescence-Activated Cell Sorter (FACS). A seven-fold cell concentration was obtained with HL60 cells and a purification efficiency of 70 % and plasma recovery of 80 % was observed for diluted (1:20) blood sample. FACS was used to identify cell lysis and the cell viability was checked using Trypan Blue test which showed that more than 99 % cells are alive indicating the suitability of the device for practical use. The proposed device has potential to be used as a sample preparation module in lab on chip based diagnostic platforms.

  5. Microfluidic-based single cell trapping using a combination of stagnation point flow and physical barrier

    Institute of Scientific and Technical Information of China (English)

    Miao Yu; Zongzheng Chen; Cheng Xiang; Bo Liu; Handi Xie; Kairong Qin

    2016-01-01

    Single cell trapping in vitro by microfluidic device is an emerging approach for the study of the rela-tionship between single cells and their dynamic biochemical microenvironments. In this paper, a hydrodynamic-based microfluidic device for single cell trapping is designed using a combination of stagnation point flow and physical barrier. The microfluidic device overcomes the weakness of the tra-ditional ones, which have been only based upon either stag-nation point flows or physical barriers, and can conveniently load dynamic biochemical signals to the trapped cell. In addi-tion, it can connect with a programmable syringe pump and a microscope to constitute an integrated experimental system. It is experimentally verified that the microfluidic system can trap single cells in vitro even under flow disturbance and con-veniently load biochemical signals to the trapped cell. The designed micro-device would provide a simple yet effective experimental platform for further study of the interactions between single cells and their microenvironments.

  6. Pump less wearable microfluidic device for real time pH sweat monitoring

    OpenAIRE

    Benito-Lopez, Fernando; Coyle, Shirley; Byrne, Robert; Smeaton, Alan F.; O'Connor, Noel E.; Diamond, Dermot

    2009-01-01

    This paper presents the fabrication and the performance of a novel, wearable, robust, flexible and disposable microfluidic device which incorporates micro-Light Emitting Diodes (μ-LEDs) as a detection system, for monitoring in real time mode the pH of the sweat generated during an exercising period.

  7. Student-Fabricated Microfluidic Devices as Flow Reactors for Organic and Inorganic Synthesis

    Science.gov (United States)

    Feng, Z. Vivian; Edelman, Kate R.; Swanson, Benjamin P.

    2015-01-01

    Flow synthesis in microfluidic devices has been rapidly adapted in the pharmaceutical industry and in many research laboratories. Yet, the cost of commercial flow reactors is a major factor limiting the dissemination of this technology in the undergraduate curriculum. Here, we present a laboratory activity where students design and fabricate…

  8. Microfluidics in the Undergraduate Laboratory: Device Fabrication and an Experiment to Mimic Intravascular Gas Embolism

    Science.gov (United States)

    Jablonski, Erin L.; Vogel, Brandon M.; Cavanagh, Daniel P.; Beers, Kathryn L.

    2010-01-01

    A method to fabricate microfluidic devices and an experimental protocol to model intravascular gas embolism for undergraduate laboratories are presented. The fabrication process details how to produce masters on glass slides; these masters serve as molds to pattern channels in an elastomeric polymer that can be adhered to a substrate, resulting in…

  9. Biomedical microfluidic devices by using low-cost fabrication techniques: A review.

    Science.gov (United States)

    Faustino, Vera; Catarino, Susana O; Lima, Rui; Minas, Graça

    2016-07-26

    One of the most popular methods to fabricate biomedical microfluidic devices is by using a soft-lithography technique. However, the fabrication of the moulds to produce microfluidic devices, such as SU-8 moulds, usually requires a cleanroom environment that can be quite costly. Therefore, many efforts have been made to develop low-cost alternatives for the fabrication of microstructures, avoiding the use of cleanroom facilities. Recently, low-cost techniques without cleanroom facilities that feature aspect ratios more than 20, for fabricating those SU-8 moulds have been gaining popularity among biomedical research community. In those techniques, Ultraviolet (UV) exposure equipment, commonly used in the Printed Circuit Board (PCB) industry, replaces the more expensive and less available Mask Aligner that has been used in the last 15 years for SU-8 patterning. Alternatively, non-lithographic low-cost techniques, due to their ability for large-scale production, have increased the interest of the industrial and research community to develop simple, rapid and low-cost microfluidic structures. These alternative techniques include Print and Peel methods (PAP), laserjet, solid ink, cutting plotters or micromilling, that use equipment available in almost all laboratories and offices. An example is the xurography technique that uses a cutting plotter machine and adhesive vinyl films to generate the master moulds to fabricate microfluidic channels. In this review, we present a selection of the most recent lithographic and non-lithographic low-cost techniques to fabricate microfluidic structures, focused on the features and limitations of each technique. Only microfabrication methods that do not require the use of cleanrooms are considered. Additionally, potential applications of these microfluidic devices in biomedical engineering are presented with some illustrative examples.

  10. A novel highly flexible, simple, rapid and low-cost fabrication tool for paper-based microfluidic devices (μPADs) using technical drawing pens and in-house formulated aqueous inks.

    Science.gov (United States)

    Nuchtavorn, Nantana; Macka, Mirek

    2016-05-01

    Paper-based microfluidic devices (μPADs) are capable of achieving rapid quantitative measurements of a variety of analytes inexpensively. μPADs rely on patterning hydrophilic-hydrophobic regions on a sheet of paper in order to create capillary channels within impermeable fluidic brakes on the paper. Here, we present a novel, highly flexible and low-cost fabrication method using a desktop digital craft plotter/cutter and technical drawing pens with tip size of 0.5 mm. The pens were used with either commercial black permanent ink for drawing fluidic brakes, or with specialty in-house formulated aqueous inks. With the permanent marker ink it was possible to create barriers on paper rapidly and in a variety of designs in a highly flexible manner. For instance, a design featuring eight reservoirs can be produced within 10 s for each μPAD with a consistent line width of brakes (%RSD < 1.5). Further, we investigated the optimal viscosity range of in-house formulated inks controlled with additions of poly(ethylene glycol). The viscosity was measured by capillary electrophoresis and the optimal viscosity was in the range of ∼3-6 mPa s. A functional test of these μPADs was conducted by the screening of antioxidant activity. Colorimetric measurements of flavonoid, phenolic compounds and DPPH free radical scavenging activity were carried out on μPADs. The results can be detected by the naked eye and simply quantified by using a camera phone and image analysis software. The fabrication method using technical drawing pens provides flexibility in the use of in-house formulated inks, short fabrication time, simplicity and low cost. PMID:27086101

  11. Continuous Separation of Multiple Size Microparticles using Alternating Current Dielectrophoresis in Microfluidic Device with Acupuncture Needle Electrodes

    Institute of Scientific and Technical Information of China (English)

    TAO Ye; REN Yukun; YAN Hui; JIANG Hongyuan

    2016-01-01

    The need to continuously separate multiple microparticles is required for the recent development of lab-on-chip technology. Dielectrophoresis(DEP)-based separation device is extensively used in kinds of microfluidic applications. However, such conventional DEP-based device is relatively complicated and difficult for fabrication. A concise microfluidic device is presented for effective continuous separation of multiple size particle mixtures. A pair of acupuncture needle electrodes are creatively employed and embedded in a PDMS(poly-dimethylsiloxane) hurdle for generating non-uniform electric field thereby achieving a continuous DEP separation. The separation mechanism is that the incoming particle samples with different sizes experience different negative DEP(nDEP) forces and then they can be transported into different downstream outlets. The DEP characterizations of particles are calculated, and their trajectories are numerically predicted by considering the combined action of the incoming laminar flow and the nDEP force field for guiding the separation experiments. The device performance is verified by successfully separating a three-sized particle mixture, including polystyrene microspheres with diameters of 3μm, 10μm and 25μm. The separation purity is below 70% when the flow rate ratio is less than 3.5 or more than 5.1, while the separation purity can be up to more than 90% when the flow rate ratio is between 3.5 and 5.1 and meanwhile ensure the voltage output falls in between 120 V and 150 V. Such simple DEP-based separation device has extensive applications in future microfluidic systems.

  12. A numerical study of droplet trapping in microfluidic devices

    Science.gov (United States)

    Nagel, Mathias; Brun, P.-T.; Gallaire, François

    2014-03-01

    Microfluidic channels are powerful means of control of minute volumes such as droplets. These droplets are usually conveyed at will in an externally imposed flow which follows the geometry of the micro-channel. It has recently been pointed out by Dangla et al. ["Trapping microfluidic drops in wells of surface energy," Phys. Rev. Lett. 107(12), 124501 (2011)] that the motion of transported droplets may also be stopped in the flow, when they are anchored to grooves which are etched in the channels top wall. This feature of the channel geometry explores a direction that is usually uniform in microfluidics. Herein, this anchoring effect exploiting the three spatial directions is studied combining a depth averaged fluid description and a geometrical model that accounts for the shape of the droplet in the anchor. First, the presented method is shown to enable the capture and release droplets in numerical simulations. Second, this tool is used in a numerical investigation of the physical mechanisms at play in the capture of the droplet: a localized reduced Laplace pressure jump is found on its interface when the droplet penetrates the groove. This modified boundary condition helps the droplet cope with the linear pressure drop in the surrounding fluid. Held on the anchor the droplet deforms and stretches in the flow. The combination of these ingredients leads to recover the scaling law for the critical capillary number at which the droplets exit the anchors C a^{star} ∝ h2/R2 where h is the channel height and R the droplet undeformed radius.

  13. Single cell analysis of yeast replicative aging using a new generation of microfluidic device.

    Directory of Open Access Journals (Sweden)

    Yi Zhang

    Full Text Available A major limitation to yeast aging study has been the inability to track mother cells and observe molecular markers during the aging process. The traditional lifespan assay relies on manual micro-manipulation to remove daughter cells from the mother, which is laborious, time consuming, and does not allow long term tracking with high resolution microscopy. Recently, we have developed a microfluidic system capable of retaining mother cells in the microfluidic chambers while removing daughter cells automatically, making it possible to observe fluorescent reporters in single cells throughout their lifespan. Here we report the development of a new generation of microfluidic device that overcomes several limitations of the previous system, making it easier to fabricate and operate, and allowing functions not possible with the previous design. The basic unit of the device consists of microfluidic channels with pensile columns that can physically trap the mother cells while allowing the removal of daughter cells automatically by the flow of the fresh media. The whole microfluidic device contains multiple independent units operating in parallel, allowing simultaneous analysis of multiple strains. Using this system, we have reproduced the lifespan curves for the known long and short-lived mutants, demonstrating the power of the device for automated lifespan measurement. Following fluorescent reporters in single mother cells throughout their lifespan, we discovered a surprising change of expression of the translation elongation factor TEF2 during aging, suggesting altered translational control in aged mother cells. Utilizing the capability of the new device to trap mother-daughter pairs, we analyzed mother-daughter inheritance and found age dependent asymmetric partitioning of a general stress response reporter between mother and daughter cells.

  14. A Microfluidic Device for Continuous-Flow Magnetically Controlled Capture and Isolation of Microparticles.

    Science.gov (United States)

    Zhou, Yao; Wang, Yi; Lin, Qiao

    2010-08-01

    This paper presents a novel microfluidic device that exploits magnetic manipulation for integrated capture and isolation of microparticles in continuous flow. The device, which was fabricated from poly(dimethylsiloxane) (PDMS) by soft-lithography techniques, consists of an incubator and a separator integrated on a single chip. The incubator is based on a novel scheme termed target acquisition by repetitive traversal (TART), in which surface-functionalized magnetic beads repetitively traverse a sample to seek out and capture target particles. This is accomplished by a judicious combination of a serpentine microchannel geometry and a time-invariant magnetic field. Subsequently, in the separator, the captured target particles are isolated from nontarget particles via magnetically driven fractionation in the same magnetic field. Due to the TART incubation scheme that uses a corner-free serpentine channel, the device has no dead volume and allows minimization of undesired particle or magnetic-bead retention. Single-chip integration of the TART incubator with the magnetic-fractionation separator further allows automated continuous isolation and retrieval of specific microparticles in an integrated manner that is free of manual off-chip sample incubation, as often required by alternative approaches. Experiments are conducted to characterize the individual incubation and separation components, as well as the integrated device. The device is found to allow 90% of target particles in a sample to be captured and isolated and 99% of nontarget particles to be eliminated. With this high separation efficiency, along with excellent reliability and flexibility, the device is well suited to sorting, purification, enrichment, and detection of micro/nanoparticles and cells in lab-on-a-chip systems. PMID:24511214

  15. Continuous cell electroporation for efficient DNA and siRNA delivery based on laminar microfluidic chips.

    Science.gov (United States)

    Wei, Zewen; Li, Zhihong

    2014-01-01

    Electroporation is a high-efficiency and low-toxicity physical gene transfer method. Traditional electroporation is limited to only low volume cell samples. Here we present a continuous cell electroporation method based on commonly used microfluidic chip fabrication technology. Using easily fabricated PDMS microfluidic chip, syringe pumps, and pulse generator, we show efficient delivery of both DNA and siRNA into different cell lines. We describe the protocol of chip fabrication, apparatus setup, and cell electroporation assay. Typically, the fabrication of the devices takes 1 or 2 days and the continuous electroporation assay takes 1 h.

  16. Designing Microfluidic Devices for Studying Cellular Responses Under Single or Coexisting Chemical/Electrical/Shear Stress Stimuli.

    Science.gov (United States)

    Chou, Tzu-Yuan; Sun, Yung-Shin; Hou, Hsien-San; Wu, Shang-Ying; Zhu, Yun; Cheng, Ji-Yen; Lo, Kai-Yin

    2016-01-01

    Microfluidic devices are capable of creating a precise and controllable cellular micro-environment of pH, temperature, salt concentration, and other physical or chemical stimuli. They have been commonly used for in vitro cell studies by providing in vivo like surroundings. Especially, how cells response to chemical gradients, electrical fields, and shear stresses has drawn many interests since these phenomena are important in understanding cellular properties and functions. These microfluidic chips can be made of glass substrates, silicon wafers, polydimethylsiloxane (PDMS) polymers, polymethylmethacrylate (PMMA) substrates, or polyethyleneterephthalate (PET) substrates. Out of these materials, PMMA substrates are cheap and can be easily processed using laser ablation and writing. Although a few microfluidic devices have been designed and fabricated for generating multiple, coexisting chemical and electrical stimuli, none of them was considered efficient enough in reducing experimental repeats, particular for screening purposes. In this report, we describe our design and fabrication of two PMMA-based microfluidic chips for investigating cellular responses, in the production of reactive oxygen species and the migration, under single or coexisting chemical/electrical/shear stress stimuli. The first chip generates five relative concentrations of 0, 1/8, 1/2, 7/8, and 1 in the culture regions, together with a shear stress gradient produced inside each of these areas. The second chip generates the same relative concentrations, but with five different electric field strengths created within each culture area. These devices not only provide cells with a precise, controllable micro-environment but also greatly increase the experimental throughput. PMID:27584698

  17. Photoinitiated grafting of porous polymer monoliths and thermoplastic polymers for microfluidic devices

    Science.gov (United States)

    Frechet, Jean M. J.; Svec, Frantisek; Rohr, Thomas

    2008-10-07

    A microfluidic device preferably made of a thermoplastic polymer that includes a channel or a multiplicity of channels whose surfaces are modified by photografting. The device further includes a porous polymer monolith prepared via UV initiated polymerization within the channel, and functionalization of the pore surface of the monolith using photografting. Processes for making such surface modifications of thermoplastic polymers and porous polymer monoliths are set forth.

  18. Microwave bonding of poly(methylmethacrylate) microfluidic devices using a conductive polymer

    OpenAIRE

    Holmes, R.J.; McDonagh, C.; McLaughlin, J.A.D.; Mohr, S.; Goddard, N J; Fielden, P.R.

    2011-01-01

    Abstract Component binding within microfluidic devices is a problem that has long been seeking a solution. In this investigation, the use of microwave radiation to seal PMMA components has been investigated using polyaniline as an absorber capable of inducting interfacial bonding. Straight microchannels were machined into PMMA using a Datron CAT3DM6 CNC machine with widths and depths across a range of 100 to 1000 microns. Prototype fluidic devices were prepared with channel pattern...

  19. Numerical analysis of wave generation and propagation in a focused surface acoustic wave device for potential microfluidics applications.

    Science.gov (United States)

    Sankaranarayanan, Subramanian K R S; Bhethanabotla, Venkat R

    2009-03-01

    We develop a 3-D finite element model of a focused surface acoustic wave (F-SAW) device based on LiNbO(3) to analyze the wave generation and propagation characteristics for devices operating at MHz frequencies with varying applied input voltages. We compare the F-SAW device to a conventional SAW device with similar substrate dimensions and transducer finger periodicity. SAW devices with concentrically shaped focused interdigital transducer fingers (F-IDTs) are found to excite waves with high intensity and high beam-width compression ratio, confined to a small localized area. F-SAW devices are more sensitive to amplitude variations at regions close to the focal point than conventional SAW devices having uniform IDT configuration. We compute F-SAW induced streaming forces and velocity fields by applying a successive approximation technique to the Navier-Stokes equation (Nyborg's theory). The maximum streaming force obtained at the focal point varies as the square of the applied input voltage. Computed streaming velocities at the focal point in F-SAW devices are at least an order of magnitude higher than those in conventional SAW devices. Simulated frequency response indicates higher insertion losses in F-SAW devices than in conventional devices, reflecting their greater utility as actuators than as sensors. Our simulation findings suggest that F-SAW devices can be utilized effectively for actuation in microfluidic applications involving diffusion limited transport processes. PMID:19411221

  20. 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.

  1. 3D-printed microfluidic device for the detection of pathogenic bacteria using size-based separation in helical channel with trapezoid cross-section.

    Science.gov (United States)

    Lee, Wonjae; Kwon, Donghoon; Choi, Woong; Jung, Gyoo Yeol; Jeon, Sangmin

    2015-01-01

    A facile method has been developed to detect pathogenic bacteria using magnetic nanoparticle clusters (MNCs) and a 3D-printed helical microchannel. Antibody-functionalized MNCs were used to capture E. coli (EC) bacteria in milk, and the free MNCs and MNC-EC complexes were separated from the milk using a permanent magnet. The free MNCs and MNC-EC complexes were dispersed in a buffer solution, then the solution was injected into a helical microchannel device with or without a sheath flow. The MNC-EC complexes were separated from the free MNCs via the Dean drag force and lift force, and the separation was facilitated in the presence of a sheath flow. The concentration of the E. coli bacteria was determined using a light absorption spectrometer, and the limit of detection was found to be 10 cfu/mL in buffer solution and 100 cfu/mL in milk. PMID:25578942

  2. A microfluidic optical platform for real-time monitoring of pH and oxygen in microfluidic bioreactors and organ-on-chip devices.

    Science.gov (United States)

    Mousavi Shaegh, Seyed Ali; De Ferrari, Fabio; Zhang, Yu Shrike; Nabavinia, Mahboubeh; Binth Mohammad, Niema; Ryan, John; Pourmand, Adel; Laukaitis, Eleanor; Banan Sadeghian, Ramin; Nadhman, Akhtar; Shin, Su Ryon; Nezhad, Amir Sanati; Khademhosseini, Ali; Dokmeci, Mehmet Remzi

    2016-07-01

    There is a growing interest to develop microfluidic bioreactors and organ-on-chip platforms with integrated sensors to monitor their physicochemical properties and to maintain a well-controlled microenvironment for cultured organoids. Conventional sensing devices cannot be easily integrated with microfluidic organ-on-chip systems with low-volume bioreactors for continual monitoring. This paper reports on the development of a multi-analyte optical sensing module for dynamic measurements of pH and dissolved oxygen levels in the culture medium. The sensing system was constructed using low-cost electro-optics including light-emitting diodes and silicon photodiodes. The sensing module includes an optically transparent window for measuring light intensity, and the module could be connected directly to a perfusion bioreactor without any specific modifications to the microfluidic device design. A compact, user-friendly, and low-cost electronic interface was developed to control the optical transducer and signal acquisition from photodiodes. The platform enabled convenient integration of the optical sensing module with a microfluidic bioreactor. Human dermal fibroblasts were cultivated in the bioreactor, and the values of pH and dissolved oxygen levels in the flowing culture medium were measured continuously for up to 3 days. Our integrated microfluidic system provides a new analytical platform with ease of fabrication and operation, which can be adapted for applications in various microfluidic cell culture and organ-on-chip devices. PMID:27648113

  3. Introducing natural thermoplastic shellac to microfluidics: A green fabrication method for point-of-care devices.

    Science.gov (United States)

    Lausecker, R; Badilita, V; Gleißner, U; Wallrabe, U

    2016-07-01

    We present a sustainable fabrication method for cheap point-of-care microfluidic systems, employing hot embossing of natural shellac as a key feature of an energy-efficient fabrication method that exclusively uses renewable materials as consumables. Shellac is a low-cost renewable biomaterial that features medium hydrophilicity (e.g., a water contact angle of ca. 73°) and a high chemical stability with respect to common solvents such as cyclohexane or toluene, rendering it an interesting candidate for low-cost microfluidics and a competitor to well-known systems such as paper-based or polydimethylsiloxane-based microfluidics. Moreover, its high replication accuracy for small features down to 30 μm lateral feature size and its ability to form smooth surfaces (surface roughness Ra  = 29 nm) at low embossing temperatures (glass transition temperature Tg  = 42.2 °C) enable energy-efficient hot embossing of microfluidic structures. Proof-of-concept for the implementation of shellac hot embossing as a green fabrication method for microfluidic systems is demonstrated through the successful fabrication of a microfluidic test setup and the assessment of its resource consumption. PMID:27478525

  4. Getting started with open-hardware: development and control of microfluidic devices.

    Science.gov (United States)

    da Costa, Eric Tavares; Mora, Maria F; Willis, Peter A; do Lago, Claudimir L; Jiao, Hong; Garcia, Carlos D

    2014-08-01

    Understanding basic concepts of electronics and computer programming allows researchers to get the most out of the equipment found in their laboratories. Although a number of platforms have been specifically designed for the general public and are supported by a vast array of on-line tutorials, this subject is not normally included in university chemistry curricula. Aiming to provide the basic concepts of hardware and software, this article is focused on the design and use of a simple module to control a series of PDMS-based valves. The module is based on a low-cost microprocessor (Teensy) and open-source software (Arduino). The microvalves were fabricated using thin sheets of PDMS and patterned using CO2 laser engraving, providing a simple and efficient way to fabricate devices without the traditional photolithographic process or facilities. Synchronization of valve control enabled the development of two simple devices to perform injection (1.6 ± 0.4 μL/stroke) and mixing of different solutions. Furthermore, a practical demonstration of the utility of this system for microscale chemical sample handling and analysis was achieved performing an on-chip acid-base titration, followed by conductivity detection with an open-source low-cost detection system. Overall, the system provided a very reproducible (98%) platform to perform fluid delivery at the microfluidic scale. PMID:24823494

  5. MEMS-based flow cytometry: microfluidics-based cell identification system by fluorescent imaging.

    Science.gov (United States)

    Wu, W K; Liang, C K; Huang, J Z

    2004-01-01

    This study utilizes MEMS technology to realize a novel low-cost microfluidics-based biochip system for flow-type cell handling. Powered by vacuum pump, the microfluidic driving system enables cells to move in order one by one in the biochip by an effect of sheath flow prefocus. Then, cells are guided to a fluorescent inspection region where two detection tasks such as cell image identification and cell counting are conducted. Currently, the glass-based biochip has been manufactured and all the related devices have been well set up in our laboratory. With this proposed prototype system, typical results about cell separation of yeast cell and PC-3 cell are available and their separated images are also presented, respectively. PMID:17270801

  6. Applications of Microfluidics for Molecular Diagnostics

    OpenAIRE

    Jayamohan, Harikrishnan; Sant, Himanshu J.; Bruce K. Gale

    2012-01-01

    Diagnostic assays implemented in microfluidic devices have developed rapidly over the past decade and are expected to become commonplace in the next few years. Hundreds of microfluidics-based approaches towards clinical diagnostics and pathogen detection have been reported with a general theme of rapid and customizable assays that are potentially cost-effective. This chapter reviews microfluidics in molecular diagnostics based on application areas with a concise review of microfluidics in gen...

  7. One-layer microfluidic device for hydrodynamic 3D self-flow-focusing operating in low flow speed

    Science.gov (United States)

    Daghighi, Yasaman; Gnyawali, Vaskar; Strohm, Eric M.; Tsai, Scott S. H.; Kolios, Michael C.

    2016-03-01

    Hydrodynamic 3D flow-focusing techniques in microfluidics are categorized as (a) sheathless techniques which require high flow rates and long channels, resulting in high operating cost and high flow rates which are inappropriate for applications with flow rate limitations, and (b) sheath-flow based techniques which usually require excessive sheath flow rate to achieve hydrodynamic 3D flow-focusing. Many devices based on these principles use complicated fabrication methods to create multi-layer microchannels. We have developed a sheath-flow based microfluidic device that is capable of hydrodynamic 3D self-flow-focusing. In this device the main flow (black ink) in a low speed, and a sheath flow, enter through two inlets and enter a 180 degree curved channel (300 × 300 μm cross-section). Main flow migrates outwards into the sheath-flow due to centrifugal effects and consequently, vertical focusing is achieved at the end of the curved channel. Then, two other sheath flows horizontally confine the main flow to achieve horizontal focusing. Thus, the core flow is three-dimensionally focused at the center of the channel at the downstream. Using centrifugal force for 3D flow-focusing in a single-layer fabricated microchannel has been previously investigated by few groups. However, their demonstrated designs required high flow speed (>1 m/s) which is not suitable for many applications that live biomedical specie are involved. Here, we introduce a new design which is operational in low flow speed (microfluidic device can be used in detecting, counting and isolating cells in many biomedical applications.

  8. 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.

  9. Acoustofluidics: Theory and simulation of streaming and radiation forces at ultrasound resonances in microfluidic devices

    DEFF Research Database (Denmark)

    Bruus, Henrik

    2009-01-01

    During the past few years, there has been an increasing interest in applying ultrasound waves to manipulate biological particles and liquids in microfluidic devices. To obtain optimized designs and functionalities of the acoustofluidic devices, more detailed theoretical studies and numerical...... simulations are called for. The basic second-order perturbation theory is presented for acoustic fields applied at ultrasound frequencies in silicon/glass systems containing water-filled microfluidic channels and chambers. For various specific device geometries, the resonance frequencies and corresponding...... fields, which are directly related to the acoustic radiation force on single particles and to the acoustic streaming of the liquid. For the radiation pressure effects, there is good agreement between theory and simulation, while the numeric results for the acoustic streaming effects are more problematic...

  10. 3-D LTCC microfluidic device as a tool for studying nanoprecipitation

    Science.gov (United States)

    Schianti, J. N.; Cerize, N. P. N.; Oliveira, A. M.; Derenzo, S.; Góngora-Rubio, M. R.

    2013-03-01

    Nanoparticles have been used to improve the properties of many cosmetic products, mainly the sunscreens materials using nanoencapsulation or nanosuspensions, improving the contact with active molecules, enhancing the sun protection effect and facilitating formulations in industrial products. Microfluidic devices offer an important possibility in producing nanoparticles in a simple way, in one step bottom up technique, continuum process with low polidispersivity, low consumption of reagents and additives. In this work, we microfabricated a 3-D LTCC microfluidic device to study the nanoprecipitation of Benzophenone-3, used as a sunscreen in pharmaceutical products. It was observed that some parameters influence the particle size related to the total fluid flow on device, the ratio between phases, and the Benzophenone-3 initial concentration. The influence of applied voltages on particle sizes was tested also. For the processing, a high voltage was applied in a Kovar tube inserted in the 3D device. The use of microfluidic device resulted in particles with 100 up to 800 nm of size, with polispersivity index below 0.3 and offering an interesting way to obtain nanoparticles. These studies are still ongoing, but early results indicate the possibility of obtaining B-3 nanostructured material.

  11. Rapid fabrication of microfluidic PDMS devices from reusable PDMS molds using laser ablation

    International Nuclear Information System (INIS)

    The conventional fabrication methods for microfluidic devices require cleanroom processes that are costly and time-consuming. We present a novel, facile, and low-cost method for rapid fabrication of polydimethylsiloxane (PDMS) molds and devices. The method consists of three main fabrication steps: female mold (FM), male mold (MM), and chip fabrication. We use a CO2 laser cutter to pattern a thin, spin-coated PDMS layer for FM fabrication. We then obtain reusable PDMS MM from the FM using PDMS/PDMS casting. Finally, a second casting step is used to replicate PDMS devices from the MM. Demolding of one PDMS layer from another is carried out without any potentially hazardous chemical surface treatment. We have successfully demonstrated that this novel method allows fabrication of microfluidic molds and devices with precise dimensions (thickness, width, length) using a single material, PDMS, which is very common across microfluidic laboratories. The whole process, from idea to device testing, can be completed in 1.5 h in a standard laboratory. (paper)

  12. Rapid fabrication of microfluidic PDMS devices from reusable PDMS molds using laser ablation

    Science.gov (United States)

    Isiksacan, Ziya; Tahsin Guler, M.; Aydogdu, Berkan; Bilican, Ismail; Elbuken, Caglar

    2016-03-01

    The conventional fabrication methods for microfluidic devices require cleanroom processes that are costly and time-consuming. We present a novel, facile, and low-cost method for rapid fabrication of polydimethylsiloxane (PDMS) molds and devices. The method consists of three main fabrication steps: female mold (FM), male mold (MM), and chip fabrication. We use a CO2 laser cutter to pattern a thin, spin-coated PDMS layer for FM fabrication. We then obtain reusable PDMS MM from the FM using PDMS/PDMS casting. Finally, a second casting step is used to replicate PDMS devices from the MM. Demolding of one PDMS layer from another is carried out without any potentially hazardous chemical surface treatment. We have successfully demonstrated that this novel method allows fabrication of microfluidic molds and devices with precise dimensions (thickness, width, length) using a single material, PDMS, which is very common across microfluidic laboratories. The whole process, from idea to device testing, can be completed in 1.5 h in a standard laboratory.

  13. Towards time-resolved serial crystallography in a microfluidic device.

    Science.gov (United States)

    Pawate, Ashtamurthy S; Šrajer, Vukica; Schieferstein, Jeremy; Guha, Sudipto; Henning, Robert; Kosheleva, Irina; Schmidt, Marius; Ren, Zhong; Kenis, Paul J A; Perry, Sarah L

    2015-07-01

    Serial methods for crystallography have the potential to enable dynamic structural studies of protein targets that have been resistant to single-crystal strategies. The use of serial data-collection strategies can circumvent challenges associated with radiation damage and repeated reaction initiation. This work utilizes a microfluidic crystallization platform for the serial time-resolved Laue diffraction analysis of macroscopic crystals of photoactive yellow protein (PYP). Reaction initiation was achieved via pulsed laser illumination, and the resultant electron-density difference maps clearly depict the expected pR(1)/pR(E46Q) and pR(2)/pR(CW) states at 10 µs and the pB1 intermediate at 1 ms. The strategies presented here have tremendous potential for extension to chemical triggering methods for reaction initiation and for extension to dynamic, multivariable analyses.

  14. Accurate and rapid micromixer for integrated microfluidic devices

    Science.gov (United States)

    Van Dam, R. Michael; Liu, Kan; Shen, Kwang -Fu Clifton; Tseng, Hsian -Rong

    2015-09-22

    The invention may provide a microfluidic mixer having a droplet generator and a droplet mixer in selective fluid connection with the droplet generator. The droplet generator comprises first and second fluid chambers that are structured to be filled with respective first and second fluids that can each be held in isolation for a selectable period of time. The first and second fluid chambers are further structured to be reconfigured into a single combined chamber to allow the first and second fluids in the first and second fluid chambers to come into fluid contact with each other in the combined chamber for a selectable period of time prior to being brought into the droplet mixer.

  15. Comparison of Pectin Hydrogel Collection Methods in Microfluidic Device

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Chaeyeon; Park, Ki-Su; Kang, Sung-Min; Kim, Jongmin; Song, YoungShin; Lee, Chang-Soo [Chungnam National University, Daejeon (Korea, Republic of)

    2015-12-15

    This study investigated the effect of different collection methods on physical properties of pectin hydrogels in microfluidic synthetic approach. The pectin hydrogels were simply produced by the incorporation of calcium ions dissolved in continuous mineral oil. Then, different collection methods, pipetting, tubing, and settling, for harvesting pectin hydrogels were applied. The settling method showed most uniform and monodispersed hydrogels. In the case of settling, a coefficient of variation was 3.46 which was lower than pipetting method (18.60) and tubing method (14.76). Under the settling method, we could control the size of hydrogels, ranging from 30 μm to 180 μm, by simple manipulation of the viscosity of pectin and volumetric flow rate of dispersed and continuous phase. Finally, according to the characteristics of simple encapsulation of biological materials, we envision that the pectin hydrogels can be applied to drug delivery, food, and biocompatible materials.

  16. Low consumption single-use microvalve for microfluidic PCB-based platforms

    International Nuclear Information System (INIS)

    In this paper, a single-use and unidirectional microvalve with low consumption of energy for PCB-based microfluidic platforms is reported. Its activation is easy because it works as a fuse. The fabrication process of the device is based on PCB technology and a typical SU-8 process, using the PCB as a substrate and SU-8 for the microfluidic channels and chambers. The microvalve is intended to be used to impulse small volumes of fluids and it has been designed to be highly integrable in PCB-based microfluidic platforms. The proposed device has been fabricated, integrated and tested in a general purpose microfluidic circuit, resulting in a low activation time, of about 100 μs, and a low consumption of energy, with a maximum of 27 mJ. These results show a significant improvement because the energy consumption is about 84% lower and the time response is about four orders of magnitude shorter if compared with similar microvalves for impulsion of fluids on PCB-based platforms. (paper)

  17. Comparison of Chip Inlet Geometry in Microfluidic Devices for Cell Studies

    Directory of Open Access Journals (Sweden)

    Yung-Shin Sun

    2016-06-01

    Full Text Available Micro-fabricated devices integrated with fluidic components provide an in vitro platform for cell studies best mimicking the in vivo micro-environment. These devices are capable of creating precise and controllable surroundings of pH value, temperature, salt concentration, and other physical or chemical stimuli. Various cell studies such as chemotaxis and electrotaxis can be performed by using such devices. Moreover, microfluidic chips are designed and fabricated for applications in cell separations such as circulating tumor cell (CTC chips. Usually, there are two most commonly used inlets in connecting the microfluidic chip to sample/reagent loading tubes: the vertical (top-loading inlet and the parallel (in-line inlet. Designing this macro-to-micro interface is believed to play an important role in device performance. In this study, by using the commercial COMSOL Multiphysics software, we compared the cell capture behavior in microfluidic devices with different inlet types and sample flow velocities. Three different inlets were constructed: the vertical inlet, the parallel inlet, and the vertically parallel inlet. We investigated the velocity field, the flow streamline, the cell capture rate, and the laminar shear stress in these inlets. It was concluded that the inlet should be designed depending on the experimental purpose, i.e., one wants to maximize or minimize cell capture. Also, although increasing the flow velocity could reduce cell sedimentation, too high shear stresses are thought harmful to cells. Our findings indicate that the inlet design and flow velocity are crucial and should be well considered in fabricating microfluidic devices for cell studies.

  18. Comparison of Chip Inlet Geometry in Microfluidic Devices for Cell Studies.

    Science.gov (United States)

    Sun, Yung-Shin

    2016-01-01

    Micro-fabricated devices integrated with fluidic components provide an in vitro platform for cell studies best mimicking the in vivo micro-environment. These devices are capable of creating precise and controllable surroundings of pH value, temperature, salt concentration, and other physical or chemical stimuli. Various cell studies such as chemotaxis and electrotaxis can be performed by using such devices. Moreover, microfluidic chips are designed and fabricated for applications in cell separations such as circulating tumor cell (CTC) chips. Usually, there are two most commonly used inlets in connecting the microfluidic chip to sample/reagent loading tubes: the vertical (top-loading) inlet and the parallel (in-line) inlet. Designing this macro-to-micro interface is believed to play an important role in device performance. In this study, by using the commercial COMSOL Multiphysics software, we compared the cell capture behavior in microfluidic devices with different inlet types and sample flow velocities. Three different inlets were constructed: the vertical inlet, the parallel inlet, and the vertically parallel inlet. We investigated the velocity field, the flow streamline, the cell capture rate, and the laminar shear stress in these inlets. It was concluded that the inlet should be designed depending on the experimental purpose, i.e., one wants to maximize or minimize cell capture. Also, although increasing the flow velocity could reduce cell sedimentation, too high shear stresses are thought harmful to cells. Our findings indicate that the inlet design and flow velocity are crucial and should be well considered in fabricating microfluidic devices for cell studies. PMID:27314318

  19. Amperometric quantification based on serial dilution microfluidic systems.

    Science.gov (United States)

    Stephan, Khaled; Pittet, Patrick; Sigaud, Monique; Renaud, Louis; Vittori, Olivier; Morin, Pierre; Ouaini, Naim; Ferrigno, Rosaria

    2009-03-01

    This paper describes a microfluidic device fabricated in poly(dimethylsiloxane) that was employed to perform amperometric quantifications using on-chip calibration curves and on-chip standard addition methods. This device integrated a network of Au electrodes within a microfluidic structure designed for automatic preparation of a series of solutions containing an electroactive molecule at a concentration linearly decreasing. This device was first characterized by fluorescence microscopy and then evaluated with a model electroactive molecule such as Fe(CN(6))(4-). Operating a quantification in this microfluidic parallel approach rather than in batch mode allows a reduced analysis time to be achieved. Moreover, the microfluidic approach is compatible with the on-chip calibration of sensors simultaneously to the analysis, therefore preventing problems due to sensor response deviation with time. When using the on-chip calibration and on-chip standard addition method, we reached concentration estimation better than 5%. We also demonstrated that compared to the calibration curve approach, the standard addition mode is less complex to operate. Indeed, in this case, it is not necessary to take into account flow rate discrepancies as in the calibration approach. PMID:19238282

  20. Oxygen-Purged Microfluidic Device to Enhance Cell Viability in Photopolymerized PEG Hydrogel Microparticles.

    Science.gov (United States)

    Xia, Bingzhao; Krutkramelis, Kaspars; Oakey, John

    2016-07-11

    Encapsulating cells within biocompatible materials is a widely used strategy for cell delivery and tissue engineering. While cells are commonly suspended within bulk hydrogel-forming solutions during gelation, substantial interest in the microfluidic fabrication of miniaturized cell encapsulation vehicles has more recently emerged. Here, we utilize multiphase microfluidics to encapsulate cells within photopolymerized picoliter-volume water-in-oil droplets at high production rates. The photoinitiated polymerization of polyethylene glycol diacrylate (PEGDA) is used to continuously produce solid particles from aqueous liquid drops containing cells and hydrogel forming solution. It is well understood that this photoinitiated addition reaction is inhibited by oxygen. In contrast to bulk polymerization in which ambient oxygen is rapidly and harmlessly consumed, allowing the polymerization reaction to proceed, photopolymerization within air permeable polydimethylsiloxane (PDMS) microfluidic devices allows oxygen to be replenished by diffusion as it is depleted. This sustained presence of oxygen and the consequential accumulation of peroxy radicals produce a dramatic effect upon both droplet polymerization and post-encapsulation cell viability. In this work we employ a nitrogen microjacketed microfluidic device to purge oxygen from flowing fluids during photopolymerization. By increasing the purging nitrogen pressure, oxygen concentration was attenuated, and increased post-encapsulation cell viability was achieved. A reaction-diffusion model was used to predict the cumulative intradroplet concentration of peroxy radicals, which corresponded directly to post-encapsulation cell viability. The nitrogen-jacketed microfluidic device presented here allows the droplet oxygen concentration to be finely tuned during cell encapsulation, leading to high post-encapsulation cell viability. PMID:27285343

  1. A droplet-to-digital (D2D) microfluidic device for single cell assays.

    Science.gov (United States)

    Shih, Steve C C; Gach, Philip C; Sustarich, Jess; Simmons, Blake A; Adams, Paul D; Singh, Seema; Singh, Anup K

    2015-01-01

    We have developed a new hybrid droplet-to-digital microfluidic platform (D2D) that integrates droplet-in-channel microfluidics with digital microfluidics (DMF) for performing multi-step assays. This D2D platform combines the strengths of the two formats-droplets-in-channel for facile generation of droplets containing single cells, and DMF for on-demand manipulation of droplets including control of different droplet volumes (pL-μL), creation of a dilution series of ionic liquid (IL), and parallel single cell culturing and analysis for IL toxicity screening. This D2D device also allows for automated analysis that includes a feedback-controlled system for merging and splitting of droplets to add reagents, an integrated Peltier element for parallel cell culture at optimum temperature, and an impedance sensing mechanism to control the flow rate for droplet generation and preventing droplet evaporation. Droplet-in-channel is well-suited for encapsulation of single cells as it allows the careful manipulation of flow rates of aqueous phase containing cells and oil to optimize encapsulation. Once single cell containing droplets are generated, they are transferred to a DMF chip via a capillary where they are merged with droplets containing IL and cultured at 30 °C. The DMF chip, in addition to permitting cell culture and reagent (ionic liquid/salt) addition, also allows recovery of individual droplets for off-chip analysis such as further culturing and measurement of ethanol production. The D2D chip was used to evaluate the effect of IL/salt type (four types: NaOAc, NaCl, [C2mim] [OAc], [C2mim] [Cl]) and concentration (four concentrations: 0, 37.5, 75, 150 mM) on the growth kinetics and ethanol production of yeast and as expected, increasing IL concentration led to lower biomass and ethanol production. Specifically, [C2mim] [OAc] had inhibitory effects on yeast growth at concentrations 75 and 150 mM and significantly reduced their ethanol production compared to cells grown

  2. 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...... rat IgG in solution. When the analyte (rat IgG) is present oligomers of beads are formed. The electrical readout of the oligomers is different compared to a zero control sample with no rat IgG. Detection of the protein has been performed in a concentration as small as 14 ng/mL. The dynamic range...... when a suspension of microscopic beads flows over a set of electrodes in a microfluidic device. Since no electrode functionalization is needed the same device can be used in a number of different assays. Using goat-anti-rat IgG functionalized polystyrene beads we have shown proof of principle detecting...

  3. From Lateral Flow Devices to a Novel Nano-Color Microfluidic Assay

    Directory of Open Access Journals (Sweden)

    Thomas Schalkhammer

    2009-07-01

    Full Text Available Improving the performance of traditional diagnostic lateral flow assays combined with new manufacturing technologies is a primary goal in the research and development plans of diagnostic companies. Taking into consideration the components of lateral flow diagnostic test kits; innovation can include modification of labels, materials and device design. In recent years, Resonance-Enhanced Absorption (REA of metal nano-particles has shown excellent applicability in bio-sensing for the detection of a variety of bio-molecular binding interactions. In a novel approach, we have now integrated REA-assays in a diagnostic microfluidic setup thus resolving the bottleneck of long incubation times inherent in previously existing REA-assays and simultaneously integrated automated fabrication techniques for diagnostics manufacture. Due to the roller-coating based technology and chemical resistance, we used PET-co-polyester as a substrate and a CO2 laser ablation system as a fast, highly precise and contactless alternative to classical micro-milling. It was possible to detect biological binding within three minutes – visible to the eye as colored text readout within the REA-fluidic device. A two-minute in-situ silver enhancement was able to enhance the resonant color additionally, if required.

  4. A Microfluidic Device for Continuous Sensing of Systemic Acute Toxicants in Drinking Water

    Directory of Open Access Journals (Sweden)

    Xinyan Zhao

    2013-12-01

    Full Text Available A bioluminescent-cell-based microfluidic device for sensing toxicants in drinking water was designed and fabricated. The system employed Vibrio fischeri cells as broad-spectrum sensors to monitor potential systemic cell toxicants in water, such as heavy metal ions and phenol. Specifically, the chip was designed for continuous detection. The chip design included two counter-flow micromixers, a T-junction droplet generator and six spiral microchannels. The cell suspension and water sample were introduced into the micromixers and dispersed into droplets in the air flow. This guaranteed sufficient oxygen supply for the cell sensors. Copper (Cu2+, zinc (Zn2+, potassium dichromate and 3,5-dichlorophenol were selected as typical toxicants to validate the sensing system. Preliminary tests verified that the system was an effective screening tool for acute toxicants although it could not recognize or quantify specific toxicants. A distinct non-linear relationship was observed between the zinc ion concentration and the Relative Luminescence Units (RLU obtained during testing. Thus, the concentration of simple toxic chemicals in water can be roughly estimated by this system. The proposed device shows great promise for an early warning system for water safety.

  5. Measurements of elastic moduli of silicone gel substrates with a microfluidic device.

    Science.gov (United States)

    Gutierrez, Edgar; Groisman, Alex

    2011-01-01

    Thin layers of gels with mechanical properties mimicking animal tissues are widely used to study the rigidity sensing of adherent animal cells and to measure forces applied by cells to their substrate with traction force microscopy. The gels are usually based on polyacrylamide and their elastic modulus is measured with an atomic force microscope (AFM). Here we present a simple microfluidic device that generates high shear stresses in a laminar flow above a gel-coated substrate and apply the device to gels with elastic moduli in a range from 0.4 to 300 kPa that are all prepared by mixing two components of a transparent commercial silicone Sylgard 184. The elastic modulus is measured by tracking beads on the gel surface under a wide-field fluorescence microscope without any other specialized equipment. The measurements have small and simple to estimate errors and their results are confirmed by conventional tensile tests. A master curve is obtained relating the mixing ratios of the two components of Sylgard 184 with the resulting elastic moduli of the gels. The rigidity of the silicone gels is less susceptible to effects from drying, swelling, and aging than polyacrylamide gels and can be easily coated with fluorescent tracer particles and with molecules promoting cellular adhesion. This work can lead to broader use of silicone gels in the cell biology laboratory and to improved repeatability and accuracy of cell traction force microscopy and rigidity sensing experiments.

  6. Measurements of elastic moduli of silicone gel substrates with a microfluidic device.

    Directory of Open Access Journals (Sweden)

    Edgar Gutierrez

    Full Text Available Thin layers of gels with mechanical properties mimicking animal tissues are widely used to study the rigidity sensing of adherent animal cells and to measure forces applied by cells to their substrate with traction force microscopy. The gels are usually based on polyacrylamide and their elastic modulus is measured with an atomic force microscope (AFM. Here we present a simple microfluidic device that generates high shear stresses in a laminar flow above a gel-coated substrate and apply the device to gels with elastic moduli in a range from 0.4 to 300 kPa that are all prepared by mixing two components of a transparent commercial silicone Sylgard 184. The elastic modulus is measured by tracking beads on the gel surface under a wide-field fluorescence microscope without any other specialized equipment. The measurements have small and simple to estimate errors and their results are confirmed by conventional tensile tests. A master curve is obtained relating the mixing ratios of the two components of Sylgard 184 with the resulting elastic moduli of the gels. The rigidity of the silicone gels is less susceptible to effects from drying, swelling, and aging than polyacrylamide gels and can be easily coated with fluorescent tracer particles and with molecules promoting cellular adhesion. This work can lead to broader use of silicone gels in the cell biology laboratory and to improved repeatability and accuracy of cell traction force microscopy and rigidity sensing experiments.

  7. From lateral flow devices to a novel nano-color microfluidic assay.

    Science.gov (United States)

    Assadollahi, Saied; Reininger, Christiane; Palkovits, Roland; Pointl, Peter; Schalkhammer, Thomas

    2009-01-01

    Improving the performance of traditional diagnostic lateral flow assays combined with new manufacturing technologies is a primary goal in the research and development plans of diagnostic companies. Taking into consideration the components of lateral flow diagnostic test kits; innovation can include modification of labels, materials and device design. In recent years, Resonance-Enhanced Absorption (REA) of metal nano-particles has shown excellent applicability in bio-sensing for the detection of a variety of bio-molecular binding interactions. In a novel approach, we have now integrated REA-assays in a diagnostic microfluidic setup thus resolving the bottleneck of long incubation times inherent in previously existing REA-assays and simultaneously integrated automated fabrication techniques for diagnostics manufacture. Due to the roller-coating based technology and chemical resistance, we used PET-co-polyester as a substrate and a CO(2) laser ablation system as a fast, highly precise and contactless alternative to classical micro-milling. It was possible to detect biological binding within three minutes - visible to the eye as colored text readout within the REA-fluidic device. A two-minute in-situ silver enhancement was able to enhance the resonant color additionally, if required. PMID:22454573

  8. Paper-based microfluidics with an erodible polymeric bridge giving controlled release and timed flow shutoff.

    Science.gov (United States)

    Jahanshahi-Anbuhi, Sana; Henry, Aleah; Leung, Vincent; Sicard, Clémence; Pennings, Kevin; Pelton, Robert; Brennan, John D; Filipe, Carlos D M

    2014-01-01

    Water soluble pullulan films were formatted into paper-based microfluidic devices, serving as a controlled time shutoff valve. The utility of the valve was demonstrated by a one-step, fully automatic implementation of a complex pesticide assay requiring timed, sequential exposure of an immobilized enzyme layer to separate liquid streams. Pullulan film dissolution and the capillary wicking of aqueous solutions through the device were measured and modeled providing valve design criteria. The films dissolve mainly by surface erosion, meaning the film thickness mainly controls the shutoff time. This method can also provide time-dependent sequential release of reagents without compromising the simplicity and low cost of paper-based devices.

  9. Volumetric measurement of human red blood cells by MOSFET-based microfluidic gate.

    Science.gov (United States)

    Guo, Jinhong; Ai, Ye; Cheng, Yuanbing; Li, Chang Ming; Kang, Yuejun; Wang, Zhiming

    2015-08-01

    In this paper, we present a MOSFET-based (metal oxide semiconductor field-effect transistor) microfluidic gate to characterize the translocation of red blood cells (RBCs) through a gate. In the microfluidic system, the bias voltage modulated by the particles or biological cells is connected to the gate of MOSFET. The particles or cells can be detected by monitoring the MOSFET drain current instead of DC/AC-gating method across the electronic gate. Polystyrene particles with various standard sizes are utilized to calibrate the proposed device. Furthermore, RBCs from both adults and newborn blood sample are used to characterize the performance of the device in distinguishing the two types of RBCs. As compared to conventional DC/AC current modulation method, the proposed device demonstrates a higher sensitivity and is capable of being a promising platform for bioassay analysis. PMID:25349117

  10. A radio frequency device for measurement of minute dielectric property changes in microfluidic channels

    Science.gov (United States)

    Song, Chunrong; Wang, Pingshan

    2009-01-01

    We demonstrate a sensitive radio frequency (rf) device to detect small dielectric property changes in microfluidic channel. The device consists of an on-chip Wilkinson power divider and a rat-race hybrid, which are built with planar microstrip lines and thin film chip resistors. Interference is used to cancel parasitic background signals. As a result, the measurement sensitivity is improved by more than 20 dB compared with conventional transmission lines. Compared with an ultrasensitive slot antenna/cuvette assembly [K. M. Taylor and D. W. van der Weide, IEEE Trans. Microwave Theory Tech. 53, 1576 (2005)], the proposed rf device is two times more sensitive.

  11. Surface treatment of flow channels in microfluidic devices fabricated by stereolithography.

    Science.gov (United States)

    Ohtani, Kanako; Tsuchiya, Masaki; Sugiyama, Hitomi; Katakura, Toru; Hayakawa, Masatoshi; Kanai, Toshimitsu

    2014-01-01

    A microfluidic device with three-dimensional flow channels was fabricated by stereolithography, and hydrophilic surface treatment of the flow channel was performed by coating the wall of the channel with a silica layer. After the treatment, the device produced monodisperse oil-in-water (O/W) emulsions. The silica layer on the channel surface was then coated with a fluorinated silane coupling agent to make it hydrophobic, thus enabling the treated device to produce monodisperse inverted water-in-oil (W/O) emulsions.

  12. Open-Source Wax RepRap 3-D Printer for Rapid Prototyping Paper-Based Microfluidics.

    Science.gov (United States)

    Pearce, J M; Anzalone, N C; Heldt, C L

    2016-08-01

    The open-source release of self-replicating rapid prototypers (RepRaps) has created a rich opportunity for low-cost distributed digital fabrication of complex 3-D objects such as scientific equipment. For example, 3-D printable reactionware devices offer the opportunity to combine open hardware microfluidic handling with lab-on-a-chip reactionware to radically reduce costs and increase the number and complexity of microfluidic applications. To further drive down the cost while improving the performance of lab-on-a-chip paper-based microfluidic prototyping, this study reports on the development of a RepRap upgrade capable of converting a Prusa Mendel RepRap into a wax 3-D printer for paper-based microfluidic applications. An open-source hardware approach is used to demonstrate a 3-D printable upgrade for the 3-D printer, which combines a heated syringe pump with the RepRap/Arduino 3-D control. The bill of materials, designs, basic assembly, and use instructions are provided, along with a completely free and open-source software tool chain. The open-source hardware device described here accelerates the potential of the nascent field of electrochemical detection combined with paper-based microfluidics by dropping the marginal cost of prototyping to nearly zero while accelerating the turnover between paper-based microfluidic designs. PMID:26763294

  13. Integrated microfluidic device for single-cell trapping and spectroscopy

    KAUST Repository

    Liberale, Carlo

    2013-02-13

    Optofluidic microsystems are key components towards lab-on-a-chip devices for manipulation and analysis of biological specimens. In particular, the integration of optical tweezers (OT) in these devices allows stable sample trapping, while making available mechanical, chemical and spectroscopic analyses.

  14. Microfluidic-based metal enhanced fluorescence for capillary electrophoresis by Ag nanorod arrays

    Science.gov (United States)

    Xiao, Chenyu; Cao, Zhen; Deng, Junhong; Huang, Zhifeng; Xu, Zheng; Fu, Junxue; Yobas, Levent

    2014-06-01

    As metal nanorods show much higher metal enhanced fluorescence (MEF) than metal nanospheres, microfluidic-based MEF is first explored with Ag nanorod (ND) arrays made by oblique angle deposition. By measuring the fluorescein isothiocyanate (FITC) solution sandwiched between the Ag NDs and a piece of cover slip, the enhancement factors (EFs) are found as 3.7 ± 0.64 and 6.74 ± 2.04, for a solution thickness at 20.8 μm and 10 μm, respectively. Because of the strong plasmonic coupling between the adjacent Ag NDs, only the emission of the fluorophores present in the three-dimensional NDs array gets enhanced. Thus, the corresponding effective enhancement factors (EEFs) are revealed to be relatively close, 259 ± 92 and 340 ± 102, respectively. To demonstrate the application of MEF in microfluidic systems, a multilayer of SiO2 NDs/Ag NDs is integrated with a capillary electrophoresis device. At a microchannel depth of 10 μm, an enhancement of 6.5 fold is obtained for amino acids separation detection. These results are very encouraging and open the possibility of MEF applications for the Ag ND arrays decorated microchannels. With the miniaturization of microfluidic devices, microfluidic-based MEF by Ag ND arrays will likely find more applications with further enhancement.

  15. Study of the Chemotactic Response of Multicellular Spheroids in a Microfluidic Device.

    Directory of Open Access Journals (Sweden)

    Jose M Ayuso

    Full Text Available We report the first application of a microfluidic device to observe chemotactic migration in multicellular spheroids. A microfluidic device was designed comprising a central microchamber and two lateral channels through which reagents can be introduced. Multicellular spheroids were embedded in collagen and introduced to the microchamber. A gradient of fetal bovine serum (FBS was established across the central chamber by addition of growth media containing serum into one of the lateral channels. We observe that spheroids of oral squamous carcinoma cells OSC-19 invade collectively in the direction of the gradient of FBS. This invasion is more directional and aggressive than that observed for individual cells in the same experimental setup. In contrast to spheroids of OSC-19, U87-MG multicellular spheroids migrate as individual cells. A study of the exposure of spheroids to the chemoattractant shows that the rate of diffusion into the spheroid is slow and thus, the chemoattractant wave engulfs the spheroid before diffusing through it.

  16. Study of the Chemotactic Response of Multicellular Spheroids in a Microfluidic Device.

    Science.gov (United States)

    Ayuso, Jose M; Basheer, Haneen A; Monge, Rosa; Sánchez-Álvarez, Pablo; Doblaré, Manuel; Shnyder, Steven D; Vinader, Victoria; Afarinkia, Kamyar; Fernández, Luis J; Ochoa, Ignacio

    2015-01-01

    We report the first application of a microfluidic device to observe chemotactic migration in multicellular spheroids. A microfluidic device was designed comprising a central microchamber and two lateral channels through which reagents can be introduced. Multicellular spheroids were embedded in collagen and introduced to the microchamber. A gradient of fetal bovine serum (FBS) was established across the central chamber by addition of growth media containing serum into one of the lateral channels. We observe that spheroids of oral squamous carcinoma cells OSC-19 invade collectively in the direction of the gradient of FBS. This invasion is more directional and aggressive than that observed for individual cells in the same experimental setup. In contrast to spheroids of OSC-19, U87-MG multicellular spheroids migrate as individual cells. A study of the exposure of spheroids to the chemoattractant shows that the rate of diffusion into the spheroid is slow and thus, the chemoattractant wave engulfs the spheroid before diffusing through it. PMID:26444904

  17. Study of the Chemotactic Response of Multicellular Spheroids in a Microfluidic Device

    Science.gov (United States)

    Ayuso, Jose M.; Basheer, Haneen A.; Monge, Rosa; Sánchez-Álvarez, Pablo; Doblaré, Manuel; Shnyder, Steven D.; Vinader, Victoria; Afarinkia, Kamyar

    2015-01-01

    We report the first application of a microfluidic device to observe chemotactic migration in multicellular spheroids. A microfluidic device was designed comprising a central microchamber and two lateral channels through which reagents can be introduced. Multicellular spheroids were embedded in collagen and introduced to the microchamber. A gradient of fetal bovine serum (FBS) was established across the central chamber by addition of growth media containing serum into one of the lateral channels. We observe that spheroids of oral squamous carcinoma cells OSC–19 invade collectively in the direction of the gradient of FBS. This invasion is more directional and aggressive than that observed for individual cells in the same experimental setup. In contrast to spheroids of OSC–19, U87-MG multicellular spheroids migrate as individual cells. A study of the exposure of spheroids to the chemoattractant shows that the rate of diffusion into the spheroid is slow and thus, the chemoattractant wave engulfs the spheroid before diffusing through it. PMID:26444904

  18. A microfluidic device for the study of the orientational dynamics of microrods

    CERN Document Server

    Mishra, Y N; John, O A; Andersson, P; Mehlig, B; Hanstorp, D

    2012-01-01

    We describe a microfluidic device for studying the orientational dynamics of microrods. The device enables us to experimentally investigate the tumbling of microrods immersed in the shear flow in a microfluidic channel with a depth of 400 mu and a width of 2.5 mm. The orientational dynamics was recorded using a 20 X microscopic objective and a CCD camera. The microrods were produced by shearing microdroplets of photocurable epoxy resin. We show different examples of empirically observed tumbling. On the one hand we find that short stretches of the experimentally determined time series are well described by fits to solutions of Jeffery's approximate equation of motion [Jeffery, Proc. R. Soc. London. 102 (1922), 161-179]. On the other hand we find that the empirically observed trajectories drift between different solutions of Jeffery's equation. We discuss possible causes of this orbit drift.

  19. Parallel combinatorial chemical synthesis using single-layer poly(dimethylsiloxane) microfluidic devices

    Science.gov (United States)

    Dexter, Joseph P.; Parker, William

    2009-01-01

    Improving methods for high-throughput combinatorial chemistry has emerged as a major area of research because of the importance of rapidly synthesizing large numbers of chemical compounds for drug discovery and other applications. In this investigation, a novel microfluidic chip for performing parallel combinatorial chemical synthesis was developed. Unlike past microfluidic systems designed for parallel combinatorial chemistry, the chip is a single-layer device made of poly(dimethylsiloxane) that is extremely easy and inexpensive to fabricate. Using the chip, a 2×2 combinatorial series of amide-formation reactions was performed. The results of this combinatorial synthesis indicate that the new device is an effective platform for running parallel organic syntheses at significantly higher throughput than with past methodologies. Additionally, a design algorithm for scaling up the 2×2 combinatorial synthesis chip to address more complex cases was developed. PMID:20216962

  20. Tissue culture on a chip: Developmental biology applications of self-organized capillary networks in microfluidic devices.

    Science.gov (United States)

    Miura, Takashi; Yokokawa, Ryuji

    2016-08-01

    Organ culture systems are used to elucidate the mechanisms of pattern formation in developmental biology. Various organ culture techniques have been used, but the lack of microcirculation in such cultures impedes the long-term maintenance of larger tissues. Recent advances in microfluidic devices now enable us to utilize self-organized perfusable capillary networks in organ cultures. In this review, we will overview past approaches to organ culture and current technical advances in microfluidic devices, and discuss possible applications of microfluidics towards the study of developmental biology. PMID:27272910

  1. Papers Based Electrochemical Biosensors: From Test Strips to Paper-Based Microfluidics

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Bingwen; Du, Dan; Hua, Xin; Yu, Xiao-Ying; Lin, Yuehe

    2014-05-08

    Papers based biosensors such as lateral flow test strips and paper-based microfluidic devices (or paperfluidics) are inexpensive, rapid, flexible, and easy-to-use analytical tools. An apparent trend in their detection is to interpret sensing results from qualitative assessment to quantitative determination. Electrochemical detection plays an important role in quantification. This review focuses on electrochemical (EC) detection enabled biosensors. The first part provides detailed examples in paper test strips. The second part gives an overview of paperfluidics engaging EC detections. The outlook and recommendation of future directions of EC enabled biosensors are discussed in the end.

  2. A novel passive microfluidic device for preprocessing whole blood for point of care diagnostics

    DEFF Research Database (Denmark)

    Shah, Pranjul Jaykumar; Dimaki, Maria; Svendsen, Winnie Edith

    2009-01-01

    A novel strategy to sort the cells of interest (White Blood Cells (leukocytes)) by selectively lysing the Red Blood Cells (erythrocytes) in a miniaturized microfluidic device is presented. Various methods to lyse cells on a chip exist i.e. electrical, mechanical, chemical and thermal but they need...... on the principle of mixing whole blood with pure water in time controlled manner to lyse erythrocytes osmotically on a chip....

  3. “Flow valve” microfluidic devices for simple, detectorless and label-free analyte quantitation

    OpenAIRE

    Chatterjee, Debolina; Mansfield, Danielle S.; Anderson, Neil G.; Subedi, Sudeep; Woolley, Adam T.

    2012-01-01

    Simplified analysis systems that offer the performance of benchtop instruments but the convenience of portability are highly desirable. We have developed novel, miniature devices that feature visual inspection readout of a target’s concentration from a ~1 μL volume of solution introduced into a microfluidic channel. Microchannels are constructed within an elastomeric material, and channel surfaces are coated with receptors to the target. When a solution is flowed into the channel, the target ...

  4. Nematic Director Reorientation at Solid and Liquid Interfaces under Flow: SAXS Studies in a Microfluidic Device

    OpenAIRE

    Silva, Bruno F. B.; Zepeda-Rosales, Miguel; Venkateswaran, Neeraja; Fletcher, Bretton J.; Carter, Lester G.; MATSUI, Tsutomu; Weiss, Thomas M.; Han, Jun; Li, Youli; Olsson, Ulf; Safinya, Cyrus R.

    2014-01-01

    In this work we investigate the interplay between flow and boundary condition effects on the orientation field of a thermotropic nematic liquid crystal under flow and confinement in a microfluidic device. Two types of experiments were performed using synchrotron small-angle X-ray-scattering (SAXS). In the first, a nematic liquid crystal flows through a square-channel cross section at varying flow rates, while the nematic director orientation projected onto the velocity/velocity gradient plane...

  5. Design, fabrication and test of a pneumatically controlled, renewable, microfluidic bead trapping device for sequential injection analysis applications

    Energy Technology Data Exchange (ETDEWEB)

    Shao, Guocheng; Lu, Donglai; Fu, Zhifeng; Du, Dan; Ozanich, Richard M.; Wang, Wanjun; Lin, Yuehe

    2016-01-01

    This paper describes the design, fabrication, and testing of a pneumatically controlled,renewable, microfluidic device for conducting bead-based assays in an automated sequential injection analysis system. The device used a “brick wall”-like pillar array (pillar size: 20 μm length X 50 μm width X 45 μm height) with 5 μm gaps between the pillars serving as the micro filter. The flow channel where bead trapping occurred is 500 μm wide X 75 μm deep. An elastomeric membrane and an air chamber were located underneath the flow channel. By applying pressure to the air chamber, the membrane is deformed and pushed upward against the filter structure. This effectively traps beads larger than 5 μm and creates a “bed” or micro column of beads that can be perfused and washed with liquid samples and reagents. Upon completion of the assay process, the pressure is released and the beads are flushed out from underneath the filter structure to renew the device. Mouse IgG was used as a model analyte to test the feasibility of using the proposed device for immunoassay applications. Resulting microbeads from an on-chip fluorescent immunoassay were individually examined using flow cytometry. The results show that the fluorescence signal intensity distribution is fairly narrow indicating high chemical reaction uniformity among the beads population. Electrochemical onchip assay was also conducted. A detection limit of 0.1 ng/mL1 ppb was achieved and good device reliability and repeatability were demonstrated. The novel microfluidic-based beadstrapping device thus opens up a new pathway to design micro-bead based biosensor immunoassays for clinical and othervarious applications.

  6. High-throughput blood cell focusing and plasma isolation using spiral inertial microfluidic devices.

    Science.gov (United States)

    Xiang, Nan; Ni, Zhonghua

    2015-12-01

    Herein, we explored the blood cell focusing and plasma isolation using a spiral inertial microfluidic device. First, the flow-rate and concentration effects on the migration dynamics of blood cells were systematically investigated to uncover the focusing mechanisms and steric crowding effects of cells in Dean-coupled inertial flows. A novel phenomenon that the focusing status of discoid red blood cells (RBCs) changes according to the channel height was discovered. These experimental data may provide valuable insights for the high-throughput processing of blood samples using inertial microfluidics. On the basis of the improved understandings on blood cell focusing, efficient isolation of plasma from whole blood with a 20-fold dilution was achieved at a throughput up to 700 μl/min. The purity of the isolated blood plasma was close to 100 %, and the plasma yield was calculated to be 38.5 %. As compared with previously-reported devices, our spiral inertial microfluidic device provides a balanced overall performance, and has overriding advantages in terms of processing throughput and operating efficiency.

  7. Integrated elastomeric components for autonomous regulation of sequential and oscillatory flow switching in microfluidic devices

    Science.gov (United States)

    Mosadegh, Bobak; Kuo, Chuan-Hsien; Tung, Yi-Chung; Torisawa, Yu-Suke; Bersano-Begey, Tommaso; Tavana, Hossein; Takayama, Shuichi

    2010-06-01

    A critical need for enhancing the usability and capabilities of microfluidic technologies is the development of standardized, scalable and versatile control systems. Electronically controlled valves and pumps typically used for dynamic flow regulation, although useful, can limit convenience, scalability and robustness. This shortcoming has motivated the development of device-embedded non-electrical flow-control systems. Existing approaches to regulate operation timing on-chip, however, still require external signals such as timed generation of fluid flow, bubbles, liquid plugs or droplets or an alteration of chemical compositions or temperature. Here, we describe a strategy to provide device-embedded flow switching and clocking functions. Physical gaps and cavities interconnected by holes are fabricated into a three-layer elastomer structure to form networks of fluidic gates that can spontaneously generate cascading and oscillatory flow output using only a constant flow of Newtonian fluids as the device input. The resulting microfluidic substrate architecture is simple, scalable and should be applicable to various materials. This flow-powered fluidic gating scheme brings the autonomous signal processing ability of microelectronic circuits to microfluidics where there is the added diversity in current information of having distinct chemical or particulate species and richness in current operation of having chemical reactions and physical interactions.

  8. A microfluidic device integrating plasmonic nanodevices for Raman spectroscopy analysis on trapped single living cells

    KAUST Repository

    Perozziello, Gerardo

    2013-11-01

    In this work we developed a microfluidic device integrating nanoplasmonic devices combined with fluidic trapping regions. The microfuidic traps allow to capture single cells in areas where plasmonic sensors are placed. In this way it is possible to perform Enhanced Raman analysis on the cell membranes. Moreover, by changing direction of the flux it is possible to change the orientation of the cell in the trap, so that it is possible to analyze different points of the membrane of the same cell. We shows an innovative procedure to fabricate and assembly the microfluidic device which combine photolithography, focused ion beam machining, and hybrid bonding between a polymer substrate and lid of Calcium fluoride. This procedure is compatible with the fabrication of the plasmonic sensors in close proximity of the microfluidic traps. Moreover, the use of Calcium fluoride as lid allows full compatibility with Raman measurements producing negligible Raman background signal and avoids Raman artifacts. Finally, we performed Raman analysis on cells to monitor their oxidative stress under particular non physiological conditions. © 2013 Elsevier B.V. All rights reserved.

  9. High-throughput blood cell focusing and plasma isolation using spiral inertial microfluidic devices.

    Science.gov (United States)

    Xiang, Nan; Ni, Zhonghua

    2015-12-01

    Herein, we explored the blood cell focusing and plasma isolation using a spiral inertial microfluidic device. First, the flow-rate and concentration effects on the migration dynamics of blood cells were systematically investigated to uncover the focusing mechanisms and steric crowding effects of cells in Dean-coupled inertial flows. A novel phenomenon that the focusing status of discoid red blood cells (RBCs) changes according to the channel height was discovered. These experimental data may provide valuable insights for the high-throughput processing of blood samples using inertial microfluidics. On the basis of the improved understandings on blood cell focusing, efficient isolation of plasma from whole blood with a 20-fold dilution was achieved at a throughput up to 700 μl/min. The purity of the isolated blood plasma was close to 100 %, and the plasma yield was calculated to be 38.5 %. As compared with previously-reported devices, our spiral inertial microfluidic device provides a balanced overall performance, and has overriding advantages in terms of processing throughput and operating efficiency. PMID:26553099

  10. 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.

  11. Fluorescence Time-lapse Imaging of the Complete S. venezuelae Life Cycle Using a Microfluidic Device.

    Science.gov (United States)

    Schlimpert, Susan; Flärdh, Klas; Buttner, Mark

    2016-01-01

    Live-cell imaging of biological processes at the single cell level has been instrumental to our current understanding of the subcellular organization of bacterial cells. However, the application of time-lapse microscopy to study the cell biological processes underpinning development in the sporulating filamentous bacteria Streptomyces has been hampered by technical difficulties. Here we present a protocol to overcome these limitations by growing the new model species, Streptomyces venezuelae, in a commercially available microfluidic device which is connected to an inverted fluorescence widefield microscope. Unlike the classical model species, Streptomyces coelicolor, S. venezuelae sporulates in liquid, allowing the application of microfluidic growth chambers to cultivate and microscopically monitor the cellular development and differentiation of S. venezuelae over long time periods. In addition to monitoring morphological changes, the spatio-temporal distribution of fluorescently labeled target proteins can also be visualized by time-lapse microscopy. Moreover, the microfluidic platform offers the experimental flexibility to exchange the culture medium, which is used in the detailed protocol to stimulate sporulation of S. venezuelae in the microfluidic chamber. Images of the entire S. venezuelae life cycle are acquired at specific intervals and processed in the open-source software Fiji to produce movies of the recorded time-series. PMID:26967231

  12. 一种纸芯片简易加工方法及在邻二氮菲-铁络合物组成测定中的应用%A Simple Method for Fabrication of Microfluidic Paper-Based Analytical Devices for Determination of Complexation Ratio Between Fe 2+ and 1,10-phenanthroline

    Institute of Scientific and Technical Information of China (English)

    蔡龙飞; 王泳

    2014-01-01

    纸芯片或纸流控分析芯片是新发展起来的一种分析技术。由于纸芯片技术在医学分析、环境分析及食品分析中的广泛应用前景,在高校中开展纸芯片的实验教学显得日益迫切。提出了一种纸芯片的简单加工技术,在此基础上设计了一个利用在纸芯片上邻二氮菲与亚铁离子的显色反应测定邻二氮菲-铁络合物组成的分析化学教学实验,实验结果与理论值相符合。%Microfluidic Paper-based Analytical Device is a newly developed analytical technique. There has been a growing need to teach paper-based microfluidic technology in teaching lab at universities, owing to its great potentials in medical testing, environmental testing and food analysis. A simple and low-cost method for fabrication of paper-based microfluidic devices was developed for determination of complexation ratio be⁃tween Fe2+ and 1,10-phenanthroline. The results determined by this method agreed well with that determined by the standard method, indicating that this presented method has great potential in teaching of analytical chemistry experiments.

  13. Design and Fabrication a Microfluidic Device for Fetal Cells Dielectrophoretic Properties Characterization

    Energy Technology Data Exchange (ETDEWEB)

    Xu Guolin [Institute of Bioengineering and Nanotechnologies, 31 Biopolis, Way, The Nanos, hashmark 04-01, Singapore 138669 (Singapore); Chan, M B [Nanyang Technological University, Singapore. 16 Nanyang Drive, Singapore 637722 (Singapore); Yang, Charles [Nanyang Technological University, Singapore. 16 Nanyang Drive, Singapore 637722 (Singapore); Sukumar, P [National University Hospital, Singapore. 10 Medical Drive, Singapore 117597 (Singapore); Choolani, M [National University Hospital, Singapore. 10 Medical Drive, Singapore 117597 (Singapore); Ying, Jackie Y [Institute of Bioengineering and Nanotechnologies, 31 Biopolis, Way, The Nanos, hashmark 04-01, Singapore 138669 (Singapore)

    2006-04-01

    The present work presents a microfluidic device with interdigitated microelectrode and microchannel for fetal nucleated red blood cell dielectrophoresis properties characterization using crossover frequency method. To obtain the electric field and its gradient along the microchannel, simulation study was done by using MAXWELL{sup TM} software. Results show maximum electric field and gradient are obtained near the electrode edge and they are affected by electrode width and the electrode gap. The crossover frequency should be obtained by keeping the cell moving near the electrode edge. The device has been successfully used in fetal cell characterization with better than 1KHz frequency repeatability, which is about 2% of the measured crossover frequency.

  14. Droplet-based Biosensing for Lab-on-a-Chip, Open Microfluidics Platforms.

    Science.gov (United States)

    Dak, Piyush; Ebrahimi, Aida; Swaminathan, Vikhram; Duarte-Guevara, Carlos; Bashir, Rashid; Alam, Muhammad A

    2016-01-01

    Low cost, portable sensors can transform health care by bringing easily available diagnostic devices to low and middle income population, particularly in developing countries. Sample preparation, analyte handling and labeling are primary cost concerns for traditional lab-based diagnostic systems. Lab-on-a-chip (LoC) platforms based on droplet-based microfluidics promise to integrate and automate these complex and expensive laboratory procedures onto a single chip; the cost will be further reduced if label-free biosensors could be integrated onto the LoC platforms. Here, we review some recent developments of label-free, droplet-based biosensors, compatible with "open" digital microfluidic systems. These low-cost droplet-based biosensors overcome some of the fundamental limitations of the classical sensors, enabling timely diagnosis. We identify the key challenges that must be addressed to make these sensors commercially viable and summarize a number of promising research directions.

  15. Droplet-based Biosensing for Lab-on-a-Chip, Open Microfluidics Platforms

    Directory of Open Access Journals (Sweden)

    Piyush Dak

    2016-04-01

    Full Text Available Low cost, portable sensors can transform health care by bringing easily available diagnostic devices to low and middle income population, particularly in developing countries. Sample preparation, analyte handling and labeling are primary cost concerns for traditional lab-based diagnostic systems. Lab-on-a-chip (LoC platforms based on droplet-based microfluidics promise to integrate and automate these complex and expensive laboratory procedures onto a single chip; the cost will be further reduced if label-free biosensors could be integrated onto the LoC platforms. Here, we review some recent developments of label-free, droplet-based biosensors, compatible with “open” digital microfluidic systems. These low-cost droplet-based biosensors overcome some of the fundamental limitations of the classical sensors, enabling timely diagnosis. We identify the key challenges that must be addressed to make these sensors commercially viable and summarize a number of promising research directions.

  16. Hydrogel Embedding of Precision-Cut Liver Slices in a Microfluidic Device Improves Drug Metabolic Activity

    NARCIS (Netherlands)

    van Midwoud, Paul M.; Verweij, Niek; Groothuis, Geny M. M.; Verpoorte, Elisabeth; Merema, M.T.

    2011-01-01

    A microfluidic-based biochip made of poly(dimethylsiloxane) was recently reported for the first time by us for the incubation of precision-cut liver slices (PCLS). In this system, PCLS are continuously exposed to flow, to keep the incubation environment stable over time. Slice behavior in the biochi

  17. TiO2 coated microfluidic devices for recoverable hydrophilic and hydrophobic patterns

    Science.gov (United States)

    Lee, Jin-Hyung; Kim, Sang Kyung; Park, Hyung-Ho; Kim, Tae Song

    2015-03-01

    We report a simple method for modifying the surfaces of plastic microfluidic devices through dynamic coating process with a nano-colloidal TiO2 sol. The surface of the thermoplastic, cyclic olefin copolymer (COC) was coated with the TiO2 film, that displayed an effective photocatalytic property. The hydrophilic surface is obtained in the TiO2-coated zone of a microfluidic channel, and TiO2 coated surface degradation can be reversed easily by UV irradiation. The present work shows a photocatalytic activity concerning the effect of TiO2 coating density, which is controlled by the number of coating cycles. The hydrophilized surface was characterized by the contact angle of water and the TiO2 coated COC surface reduced the water contact angle from 85° to less than 10° upon UV irradiation. The photocatalytic effect of the layer that was coated five times with TiO2 was excellent, and the super-hydrophilicity of the TiO2 surface could be promptly recovered after 10 months of storage at atmospheric conditions. The COC microfluidic devices, in which TiO2 has been freshly deposited and aged for 10 months, were capable of generating water-in oil-in water (W/O/W) double emulsions easily and uniformly by simple control of the flow rates for demonstration of excellent hydrophilic patterning and recovery of the TiO2 coated in the microchannels.

  18. Designing and modeling a centrifugal microfluidic device to separate target blood cells

    Science.gov (United States)

    Shamloo, Amir; Selahi, AmirAli; Madadelahi, Masoud

    2016-03-01

    The objective of this study is to design a novel and efficient portable lab-on-a-CD (LOCD) microfluidic device for separation of specific cells (target cells) using magnetic beads. In this study the results are shown for neutrophils as target cells. However, other kinds of target cells can be separated in a similar approach. The designed microfluidics can be utilized as a point of care system for neutrophil detection. This microfluidic system employs centrifugal and magnetic forces for separation. After model validation by the experimental data in the literature (that may be used as a design tool for developing centrifugo-magnetophoretic devices), two models are presented for separation of target cells using magnetic beads. The first model consists of one container in the inlet section and two containers in the outlets. Initially, the inlet container is filled with diluted blood sample which is a mixture of red blood cells (RBCs) plus neutrophils which are attached to Magnetic beads. It is shown that by using centrifugal and magnetic forces, this model can separate all neutrophils with recovery factor of ~100%. In the second model, due to excess of magnetic beads in usual experimental analysis (to ensure that all target cells are attached to them) the geometry is improved by adding a third outlet for these free magnetic beads. It is shown that at angular velocity of 45 rad s-1, recovery factor of 100% is achievable for RBCs, free magnetic beads and neutrophils as target cells.

  19. Designing and modeling a centrifugal microfluidic device to separate target blood cells

    International Nuclear Information System (INIS)

    The objective of this study is to design a novel and efficient portable lab-on-a-CD (LOCD) microfluidic device for separation of specific cells (target cells) using magnetic beads. In this study the results are shown for neutrophils as target cells. However, other kinds of target cells can be separated in a similar approach. The designed microfluidics can be utilized as a point of care system for neutrophil detection. This microfluidic system employs centrifugal and magnetic forces for separation. After model validation by the experimental data in the literature (that may be used as a design tool for developing centrifugo-magnetophoretic devices), two models are presented for separation of target cells using magnetic beads. The first model consists of one container in the inlet section and two containers in the outlets. Initially, the inlet container is filled with diluted blood sample which is a mixture of red blood cells (RBCs) plus neutrophils which are attached to Magnetic beads. It is shown that by using centrifugal and magnetic forces, this model can separate all neutrophils with recovery factor of ∼100%. In the second model, due to excess of magnetic beads in usual experimental analysis (to ensure that all target cells are attached to them) the geometry is improved by adding a third outlet for these free magnetic beads. It is shown that at angular velocity of 45 rad s−1, recovery factor of 100% is achievable for RBCs, free magnetic beads and neutrophils as target cells. (paper)

  20. A Supramolecular Sensing Platform for Phosphate Anions and an Anthrax Biomarker in a Microfluidic Device

    Directory of Open Access Journals (Sweden)

    Jurriaan Huskens

    2011-10-01

    Full Text Available A supramolecular platform based on self-assembled monolayers (SAMs has been implemented in a microfluidic device. The system has been applied for the sensing of two different analyte types: biologically relevant phosphate anions and aromatic carboxylic acids, which are important for anthrax detection. A Eu(III-EDTA complex was bound to β-cyclodextrin monolayers via orthogonal supramolecular host-guest interactions. The self-assembly of the Eu(III-EDTA conjugate and naphthalene β-diketone as an antenna resulted in the formation of a highly luminescent lanthanide complex on the microchannel surface. Detection of different phosphate anions and aromatic carboxylic acids was demonstrated by monitoring the decrease in red emission following displacement of the antenna by the analyte. Among these analytes, adenosine triphosphate (ATP and pyrophosphate, as well as dipicolinic acid (DPA which is a biomarker for anthrax, showed a strong response. Parallel fabrication of five sensing SAMs in a single multichannel chip was performed, as a first demonstration of phosphate and carboxylic acid screening in a multiplexed format that allows a general detection platform for both analyte systems in a single test run with µM and nM detection sensitivity for ATP and DPA, respectively.

  1. Performance study of microfluidic devices for blood plasma separation—a designer’s perspective

    Science.gov (United States)

    Tripathi, Siddhartha; Bala Varun Kumar, Y. V.; Prabhakar, Amit; Joshi, Suhas S.; Agrawal, Amit

    2015-08-01

    In this work, design and experiments on various blood plasma microdevices based on hydrodynamic flow separation techniques is carried out. We study their performance as a function of dependent governing parameters such as flow rate, feed hematocrit, and microchannel geometry. This work focuses on understanding separation phenomena in simple geometries; subsequently, individual simple geometrical parameters and biophysical effects are combined to fabricate hybridized designs, resulting in higher separation efficiencies. The distinctive features of our microfluidic devices are that they employ elevated dimensions (of the order of hundreds of microns), and thereby can be operated continuously over sufficient duration without clogging, while simplicity of fabrication makes them cost effective. The microdevices have been experimentally demonstrated over the entire range of hematocrit (i.e. from Hct 7% to Hct 45%). A high separation efficiency of about (78.34  ±  2.7)% with pure blood is achieved in our best hybrid design. We believe that the theory and experimental results presented in this study will aid designers and researchers working in the field of blood plasma separation microdevices.

  2. Microfluidic paper-based biomolecule preconcentrator based on ion concentration polarization.

    Science.gov (United States)

    Han, Sung Il; Hwang, Kyo Seon; Kwak, Rhokyun; Lee, Jeong Hoon

    2016-06-21

    Microfluidic paper-based analytical devices (μPADs) for molecular detection have great potential in the field of point-of-care diagnostics. Currently, a critical problem being faced by μPADs is improving their detection sensitivity. Various preconcentration processes have been developed, but they still have complicated structures and fabrication processes to integrate into μPADs. To address this issue, we have developed a novel paper-based preconcentrator utilizing ion concentration polarization (ICP) with minimal addition on lateral-flow paper. The cation selective membrane (i.e., Nafion) is patterned on adhesive tape, and this tape is then attached to paper-based channels. When an electric field is applied across the Nafion, ICP is initiated to preconcentrate the biomolecules in the paper channel. Departing from previous paper-based preconcentrators, we maintain steady lateral fluid flow with the separated Nafion layer; as a result, fluorescent dyes and proteins (FITC-albumin and bovine serum albumin) are continuously delivered to the preconcentration zone, achieving high preconcentration performance up to 1000-fold. In addition, we demonstrate that the Nafion-patterned tape can be integrated with various geometries (multiplexed preconcentrator) and platforms (string and polymer microfluidic channel). This work would facilitate integration of various ICP devices, including preconcentrators, pH/concentration modulators, and micro mixers, with steady lateral flows in paper-based platforms. PMID:27199301

  3. A microfluidic device for on-chip agarose microbead generation with ultralow reagent consumption.

    Science.gov (United States)

    Desbois, Linda; Padirac, Adrien; Kaneda, Shohei; Genot, Anthony J; Rondelez, Yannick; Hober, Didier; Collard, Dominique; Fujii, Teruo

    2012-01-01

    Water-in-oil microdroplets offer microreactors for compartmentalized biochemical reactions with high throughput. Recently, the combination with a sol-gel switch ability, using agarose-in-oil microdroplets, has increased the range of possible applications, allowing for example the capture of amplicons in the gel phase for the preservation of monoclonality during a PCR reaction. Here, we report a new method for generating such agarose-in-oil microdroplets on a microfluidic device, with minimized inlet dead volume, on-chip cooling, and in situ monitoring of biochemical reactions within the gelified microbeads. We used a flow-focusing microchannel network and successfully generated agarose microdroplets at room temperature using the "push-pull" method. This method consists in pushing the oil continuous phase only, while suction is applied to the device outlet. The agarose phase present at the inlet is thus aspirated in the device, and segmented in microdroplets. The cooling system consists of two copper wires embedded in the microfluidic device. The transition from agarose microdroplets to microbeads provides additional stability and facilitated manipulation. We demonstrate the potential of this method by performing on-chip a temperature-triggered DNA isothermal amplification in agarose microbeads. Our device thus provides a new way to generate microbeads with high throughput and no dead volume for biochemical applications. PMID:24106525

  4. Digital microfluidic magnetic separation for particle-based immunoassays.

    Science.gov (United States)

    Ng, Alphonsus H C; Choi, Kihwan; Luoma, Robert P; Robinson, John M; Wheeler, Aaron R

    2012-10-16

    We introduce a new format for particle-based immunoassays relying on digital microfluidics (DMF) and magnetic forces to separate and resuspend antibody-coated paramagnetic particles. In DMF, fluids are electrostatically controlled as discrete droplets (picoliters to microliters) on an array of insulated electrodes. By applying appropriate sequences of potentials to these electrodes, multiple droplets can be manipulated simultaneously and various droplet operations can be achieved using the same device design. This flexibility makes DMF well-suited for applications that require complex, multistep protocols such as immunoassays. Here, we report the first particle-based immunoassay on DMF without the aid of oil carrier fluid to enable droplet movement (i.e., droplets are surrounded by air instead of oil). This new format allowed the realization of a novel on-chip particle separation and resuspension method capable of removing greater than 90% of unbound reagents in one step. Using this technique, we developed methods for noncompetitive and competitive immunoassays, using thyroid stimulating hormone (TSH) and 17β-estradiol (E2) as model analytes, respectively. We show that, compared to conventional methods, the new DMF approach reported here reduced reagent volumes and analysis time by 100-fold and 10-fold, respectively, while retaining a level of analytical performance required for clinical screening. Thus, we propose that the new technique has great potential for eventual use in a fast, low-waste, and inexpensive instrument for the quantitative analysis of proteins and small molecules in low sample volumes. PMID:23013543

  5. Experimental and numerical studies of a microfluidic device with compliant chambers for flow stabilization

    International Nuclear Information System (INIS)

    This paper reports experimental and numerical studies of a passive microfluidic device that stabilizes a pulsating incoming flow and delivers a steady flow at the outlet. The device employs a series of chambers along the flow direction with a thin polymeric membrane (of thickness 75–250 µm) serving as the compliant boundary. The deformation of the membrane allows accumulation of fluid during an overflow and discharge of fluid during an underflow for flow stabilization. Coupled fluid-structure simulations are performed using Mooney–Rivlin formulations to account for a thin hyperelastic membrane material undergoing large deformations to accurately predict the device performance. The device was fabricated with PDMS as the substrate material and thin PDMS membrane as the compliant boundary. The performance of the device is defined in terms of a parameter called ‘Attenuation Factor (AF)’. The effect of various design parameters including membrane thickness, elastic modulus, chamber size and number of chambers in series as well as operating conditions including the outlet pressure, mean input flow rate, fluctuation amplitude and frequency on the device performance were studied using experiments and simulations. The simulation results successfully confront the experimental data (within 10%) which validates the numerical simulations. The device was used at the exit of a PZT actuated valveless micropump to take pulsating flow at the upstream and deliver steady flow downstream. The amplitude of the pulsating flow delivered by the micropump was significantly reduced (AF = 0.05 for a device with three 4 mm chambers) but at the expense of a reduction in the pressure capability (<20%). The proposed device could potentially be used for reducing flow pulsations in practical microfluidic circuits. (paper)

  6. Experimental and numerical studies of a microfluidic device with compliant chambers for flow stabilization

    Science.gov (United States)

    Iyer, V.; Raj, A.; Annabattula, R. K.; Sen, A. K.

    2015-07-01

    This paper reports experimental and numerical studies of a passive microfluidic device that stabilizes a pulsating incoming flow and delivers a steady flow at the outlet. The device employs a series of chambers along the flow direction with a thin polymeric membrane (of thickness 75-250 µm) serving as the compliant boundary. The deformation of the membrane allows accumulation of fluid during an overflow and discharge of fluid during an underflow for flow stabilization. Coupled fluid-structure simulations are performed using Mooney-Rivlin formulations to account for a thin hyperelastic membrane material undergoing large deformations to accurately predict the device performance. The device was fabricated with PDMS as the substrate material and thin PDMS membrane as the compliant boundary. The performance of the device is defined in terms of a parameter called ‘Attenuation Factor (AF)’. The effect of various design parameters including membrane thickness, elastic modulus, chamber size and number of chambers in series as well as operating conditions including the outlet pressure, mean input flow rate, fluctuation amplitude and frequency on the device performance were studied using experiments and simulations. The simulation results successfully confront the experimental data (within 10%) which validates the numerical simulations. The device was used at the exit of a PZT actuated valveless micropump to take pulsating flow at the upstream and deliver steady flow downstream. The amplitude of the pulsating flow delivered by the micropump was significantly reduced (AF = 0.05 for a device with three 4 mm chambers) but at the expense of a reduction in the pressure capability (<20%). The proposed device could potentially be used for reducing flow pulsations in practical microfluidic circuits.

  7. Microfluidic devices for analysis of spatial orientation behaviors in semi-restrained Caenorhabditis elegans.

    Directory of Open Access Journals (Sweden)

    Kathryn E McCormick

    Full Text Available This article describes the fabrication and use of microfluidic devices for investigating spatial orientation behaviors in nematode worms (Caenorhabditis elegans. Until now, spatial orientation has been studied in freely moving nematodes in which the frequency and nature of encounters with the gradient are uncontrolled experimental variables. In the new devices, the nematode is held in place by a restraint that aligns the longitudinal axis of the body with the border between two laminar fluid streams, leaving the animal's head and tail free to move. The content of the fluid streams can be manipulated to deliver step gradients in space or time. We demonstrate the utility of the device by identifying previously uncharacterized aspects of the behavioral mechanisms underlying chemotaxis, osmotic avoidance, and thermotaxis in this organism. The new devices are readily adaptable to behavioral and imaging studies involving fluid borne stimuli in a wide range of sensory modalities.

  8. Topology optimization of flexible micro-fluidic devices

    DEFF Research Database (Denmark)

    Kreissl, Sebastian; Pingen, Georg; Evgrafov, Anton;

    2010-01-01

    A multi-objective topology optimization formulation for the design of dynamically tunable fluidic devices is presented. The flow is manipulated via external and internal mechanical actuation, leading to elastic deformations of flow channels. The design objectives characterize the performance...... in the undeformed and deformed configurations. The layout of fluid channels is determined by material topology optimization. In addition, the thickness distribution, the distribution of active material for internal actuation, and the support conditions are optimized. The coupled fluid-structure response...... is predicted by a non-linear finite element model and a hydrodynamic lattice Boltzmann method. Focusing on applications with low flow velocities and pressures, structural deformations due to fluid-forces are neglected. A mapping scheme is presented that couples the material distributions in the structural...

  9. Building a better cell trap: Applying Lagrangian modeling to the design of microfluidic devices for cell biology

    Science.gov (United States)

    Kim, Min-Cheol; Wang, Zhanhui; Lam, Raymond H. W.; Thorsen, Todd

    2008-02-01

    In this report, we show how computational fluid dynamics can be applied to the design of efficient hydrodynamic cell traps in microfluidic devices. Modeled hydrodynamic trap designs included a large, multiple-aperture "C-type" sieve for trapping hundreds of cells, flat single-aperture arrays for single cells, and "U-type" hydrodynamic structures with one or two apertures to confine small clusters of cells (˜10-15 cells per trap). Using 3T3 cells as a model system, the motion of each individual cell was calculated using a one-way coupled Lagrangian method. The cell was assumed to be a solid sphere, and interactions with other cells were only considered when a cell sedimented in the trap. The ordinary differential equations were solved along the cell trajectory for the three components of the velocity and location vector by using the Rosenbrock method based on an adaptive time-stepping technique. Validation of the predictive value of modeling, using 3T3 cells flowed through microfluidic devices containing "U-type sieves" under the simulation flow parameters, showed excellent agreement between experiment and simulation with respect to cell number per trap and the uniformity of cell distribution within individual microchambers. For applications such as on-chip cell culture or high-throughput screening of cell populations within a lab-on-a-chip environment, Lagrangian simulations have the potential to greatly simplify the design process.

  10. Low-temperature bonded glass-membrane microfluidic device for in vitro organ-on-a-chip cell culture models

    Science.gov (United States)

    Pocock, Kyall J.; Gao, Xiaofang; Wang, Chenxi; Priest, Craig; Prestidge, Clive A.; Mawatari, Kazuma; Kitamori, Takehiko; Thierry, Benjamin

    2015-12-01

    The integration of microfluidics with living biological systems has paved the way to the exciting concept of "organson- a-chip", which aims at the development of advanced in vitro models that replicate the key features of human organs. Glass based devices have long been utilised in the field of microfluidics but the integration of alternative functional elements within multi-layered glass microdevices, such as polymeric membranes, remains a challenge. To this end, we have extended a previously reported approach for the low-temperature bonding of glass devices that enables the integration of a functional polycarbonate porous membrane. The process was initially developed and optimised on specialty low-temperature bonding equipment (μTAS2001, Bondtech, Japan) and subsequently adapted to more widely accessible hot embosser units (EVG520HE Hot Embosser, EVG, Austria). The key aspect of this method is the use of low temperatures compatible with polymeric membranes. Compared to borosilicate glass bonding (650 °C) and quartz/fused silica bonding (1050 °C) processes, this method maintains the integrity and functionality of the membrane (Tg 150 °C for polycarbonate). Leak tests performed showed no damage or loss of integrity of the membrane for up to 150 hours, indicating sufficient bond strength for long term cell culture. A feasibility study confirmed the growth of dense and functional monolayers of Caco-2 cells within 5 days.

  11. Advances in microfluidics-based experimental methods for neuroscience research.

    Science.gov (United States)

    Park, Jae Woo; Kim, Hyung Joon; Kang, Myeong Woo; Jeon, Noo Li

    2013-02-21

    The application of microfluidics to neuroscience applications has always appealed to neuroscientists because of the capability to control the cellular microenvironment in both a spatial and temporal manner. Recently, there has been rapid development of biological micro-electro-mechanical systems (BioMEMS) for both fundamental and applied neuroscience research. In this review, we will discuss the applications of BioMEMS to various topics in the field of neuroscience. The purpose of this review is to summarise recent advances in the components and design of the BioMEMS devices, in vitro disease models, electrophysiology and neural stem cell research. We envision that microfluidics will play a key role in future neuroscience research, both fundamental and applied research.

  12. Development of optical sensing system for detection of Fe ions using conductive polymer actuator based microfluidic pump

    OpenAIRE

    Kim, Jung Ho; Lau, King-Tong; Fay, Cormac; Diamond, Dermot

    2008-01-01

    In this paper, we present a novel microfluidic optical sensing system by combining a low-power conductive polymer -based microfluidic pump and a microfluidic chip integrated with an optical sensor. A self priming microfluidic pump is developed using a polypyrrole. A microfluidic chip- optical detector module that contained an optical cuvette with LED and photo-diode optical sensing module was fabricated. Integration of the micro pump and the microfluidic chips complete...

  13. Microfluidic CARS cytometry

    OpenAIRE

    Wang, Han-Wei; Bao, Ning; Le, Thuc T.; Lu, Chang; Cheng, Ji-Xin

    2008-01-01

    Coherent anti-stokes Raman scattering (CARS) flow cytometry was demonstrated by combining a laser-scanning CARS microscope with a polydimethylsiloxane (PDMS) based microfluidic device. Line-scanning across the hydrodynamically focused core stream was performed for detection of flowing objects. Parameters were optimized by utilizing polystyrene beads as flowing particles. Population measurements of adipocytes isolated from mouse fat tissues demonstrated the viability of microfluidic CARS cytom...

  14. Long-Term Growth of Moss in Microfluidic Devices Enables Subcellular Studies in Development.

    Science.gov (United States)

    Bascom, Carlisle S; Wu, Shu-Zon; Nelson, Katherine; Oakey, John; Bezanilla, Magdalena

    2016-09-01

    Key developmental processes that occur on the subcellular and cellular level or occur in occluded tissues are difficult to access, let alone image and analyze. Recently, culturing living samples within polydimethylsiloxane (PDMS) microfluidic devices has facilitated the study of hard-to-reach developmental events. Here, we show that an early diverging land plant, Physcomitrella patens, can be continuously cultured within PDMS microfluidic chambers. Because the PDMS chambers are bonded to a coverslip, it is possible to image P. patens development at high resolution over long time periods. Using PDMS chambers, we report that wild-type protonemal tissue grows at the same rate as previously reported for growth on solid medium. Using long-term imaging, we highlight key developmental events, demonstrate compatibility with high-resolution confocal microscopy, and obtain growth rates for a slow-growing mutant. By coupling the powerful genetic tools available to P. patens with long-term growth and imaging provided by PDMS microfluidic chambers, we demonstrate the capability to study cellular and subcellular developmental events in plants directly and in real time.

  15. Fast and sensitive detection of an anthrax biomarker using SERS-based solenoid microfluidic sensor.

    Science.gov (United States)

    Gao, Rongke; Ko, Juhui; Cha, Kiweon; Jeon, Jun Ho; Rhie, Gi-eun; Choi, Jonghoon; deMello, Andrew J; Choo, Jaebum

    2015-10-15

    We report the application of a fully automated surface-enhanced Raman scattering (SERS)-based solenoid-embedded microfluidic device to the quantitative and sensitive detection of anthrax biomarker poly-γ-D-glutamic acid (PGA) in solution. Analysis is based on the competitive reaction between PGA and PGA-conjugated gold nanoparticles with anti-PGA-immobilized magnetic beads within a microfluidic environment. Magnetic immunocomplexes are trapped by yoke-type solenoids embedded within the device, and their SERS signals were directly measured and analyzed. To improve the accuracy of measurement process, external standard values for PGA-free serum were also measured through use of a control channel. This additional measurement greatly improves the reliability of the assay by minimizing the influence of extraneous experimental variables. The limit of detection (LOD) of PGA in serum, determined by our SERS-based microfluidic sensor, is estimated to be 100 pg/mL. We believe that the defined method represents a valuable analytical tool for the detection of anthrax-related aqueous samples.

  16. Microfluidic electrochemical device and process for chemical imaging and electrochemical analysis at the electrode-liquid interface in-situ

    Science.gov (United States)

    Yu, Xiao-Ying; Liu, Bingwen; Yang, Li; Zhu, Zihua; Marshall, Matthew J.

    2016-03-01

    A microfluidic electrochemical device and process are detailed that provide chemical imaging and electrochemical analysis under vacuum at the surface of the electrode-sample or electrode-liquid interface in-situ. The electrochemical device allows investigation of various surface layers including diffuse layers at selected depths populated with, e.g., adsorbed molecules in which chemical transformation in electrolyte solutions occurs.

  17. Flexible microfluidic device for mechanical property characterization of soft viscoelastic solids such as bacterial biofilms.

    Science.gov (United States)

    Hohne, Danial N; Younger, John G; Solomon, Michael J

    2009-07-01

    We introduce a flexible microfluidic device to characterize the mechanical properties of soft viscoelastic solids such as bacterial biofilms. In the device, stress is imposed on a test specimen by the application of a fixed pressure to a thin, flexible poly(dimethyl siloxane) (PDMS) membrane that is in contact with the specimen. The stress is applied by pressurizing a microfabricated air channel located above the test area. The strain resulting from the applied stress is quantified by measuring the membrane deflection with a confocal laser scanning microscope. The deflection is governed by the viscoelastic properties of the PDMS membrane and of the test specimen. The relative contributions of the membrane and test material to the measured deformation are quantified by comparing a finite element analysis with an independent (control) measurement of the PDMS membrane mechanical properties. The flexible microfluidic rheometer was used to characterize both the steady-state elastic modulus and the transient strain recoil of two soft materials: gellan gums and bacterial biofilms. The measured linear elastic moduli and viscoelastic relaxation times of gellan gum solutions were in good agreement with the results of conventional mechanical rheometry. The linear Young's moduli of biofilms of Staphylococcus epidermidis and Klebsiella pneumoniae, which could not be measured using conventional methods, were found to be 3.2 and 1.1 kPa, respectively, and the relaxation time of the S. epidermidis biofilm was 13.8 s. Additionally, strain hardening was observed in all the biofilms studied. Finally, design parameters and detection limits of the method show that the device is capable of characterizing soft viscoelastic solids with elastic moduli in the range of 102-105 Pa. The flexible microfluidic rheometer addresses the need for mechanical property characterization of soft viscoelastic solids common in fields such as biomaterials, food, and consumer products. It requires only 200 p

  18. Flexible microfluidic device for mechanical property characterization of soft viscoelastic solids such as bacterial biofilms.

    Science.gov (United States)

    Hohne, Danial N; Younger, John G; Solomon, Michael J

    2009-07-01

    We introduce a flexible microfluidic device to characterize the mechanical properties of soft viscoelastic solids such as bacterial biofilms. In the device, stress is imposed on a test specimen by the application of a fixed pressure to a thin, flexible poly(dimethyl siloxane) (PDMS) membrane that is in contact with the specimen. The stress is applied by pressurizing a microfabricated air channel located above the test area. The strain resulting from the applied stress is quantified by measuring the membrane deflection with a confocal laser scanning microscope. The deflection is governed by the viscoelastic properties of the PDMS membrane and of the test specimen. The relative contributions of the membrane and test material to the measured deformation are quantified by comparing a finite element analysis with an independent (control) measurement of the PDMS membrane mechanical properties. The flexible microfluidic rheometer was used to characterize both the steady-state elastic modulus and the transient strain recoil of two soft materials: gellan gums and bacterial biofilms. The measured linear elastic moduli and viscoelastic relaxation times of gellan gum solutions were in good agreement with the results of conventional mechanical rheometry. The linear Young's moduli of biofilms of Staphylococcus epidermidis and Klebsiella pneumoniae, which could not be measured using conventional methods, were found to be 3.2 and 1.1 kPa, respectively, and the relaxation time of the S. epidermidis biofilm was 13.8 s. Additionally, strain hardening was observed in all the biofilms studied. Finally, design parameters and detection limits of the method show that the device is capable of characterizing soft viscoelastic solids with elastic moduli in the range of 102-105 Pa. The flexible microfluidic rheometer addresses the need for mechanical property characterization of soft viscoelastic solids common in fields such as biomaterials, food, and consumer products. It requires only 200 p

  19. Room-temperature intermediate layer bonding for microfluidic devices

    NARCIS (Netherlands)

    Bart, J.; Tiggelaar, R.; Yang, M.L.; Schlautmann, S.; Zuilhof, H.; Gardeniers, H.

    2009-01-01

    In this work a novel room-temperature bonding technique based on chemically activated Fluorinated Ethylene Propylene (FEP) sheet as an intermediate between chemically activated substrates is presented. Surfaces of silicon and glass substrates are chemically modified with APTES bearing amine terminal

  20. A microfluidic device for simple and rapid evaluation of multidrug efflux pump inhibitors

    Directory of Open Access Journals (Sweden)

    Ryota eIino

    2012-02-01

    Full Text Available Recently, multidrug resistant pathogens have disseminated widely owing essentially to their increased multidrug efflux pump activity. Presently, there is a scarcity of new antibacterial agents, and hence, inhibitors of multidrug efflux pumps belonging to the resistance-nodulation-cell division (RND family appear useful in the treatment of infections by multidrug-resistant pathogens. Moreover, recent progress in microfabrication technologies has expanded the application of nano/micro-devices to the field of human healthcare, such as the detection of infections and diagnosis of diseases. We developed a microfluidic channel device for a simple and rapid evaluation of bacterial drug efflux activity. By combining the microfluidic device with a fluorogenic compound, fluorescein-di-β-D-galactopyranoside, which is hydrolyzed to a fluorescent dye in the cytoplasm of Escherichia coli, we successfully evaluated the effects of inhibitors on the RND-type multidrug efflux pumps MexAB-OprM and MexXY-OprM from Pseudomonas aeruginosa in E. coli. Our new method successfully detected the MexB-specific inhibitory effect of D13-9001 and revealed an unexpected membrane-permeabilizing effect of Phe-Arg-β-naphthylamide, which has long been used as an inhibitor.

  1. Magnetophoresis 'meets' viscoelasticity: deterministic separation of magnetic particles in a modular microfluidic device.

    Science.gov (United States)

    Del Giudice, Francesco; Madadi, Hojjat; Villone, Massimiliano M; D'Avino, Gaetano; Cusano, Angela M; Vecchione, Raffaele; Ventre, Maurizio; Maffettone, Pier Luca; Netti, Paolo A

    2015-04-21

    The deflection of magnetic beads in a microfluidic channel through magnetophoresis can be improved if the particles are somehow focused along the same streamline in the device. We design and fabricate a microfluidic device made of two modules, each one performing a unit operation. A suspension of magnetic beads in a viscoelastic medium is fed to the first module, which is a straight rectangular-shaped channel. Here, the magnetic particles are focused by exploiting fluid viscoelasticity. Such a channel is one inlet of the second module, which is a H-shaped channel, where a buffer stream is injected in the second inlet. A permanent magnet is used to displace the magnetic beads from the original to the buffer stream. Experiments with a Newtonian suspending fluid, where no focusing occurs, are carried out for comparison. When viscoelastic focusing and magnetophoresis are combined, magnetic particles can be deterministically separated from the original streamflow to the buffer, thus leading to a high deflection efficiency (up to ~96%) in a wide range of flow rates. The effect of the focusing length on the deflection of particles is also investigated. Finally, the proposed modular device is tested to separate magnetic and non-magnetic beads. PMID:25732596

  2. Immobilization Techniques and Integrated Signal Enhancement for POC Nanocolor Microfluidic Devices

    Directory of Open Access Journals (Sweden)

    Marlies Schlauf

    2015-01-01

    Full Text Available Resonance enhanced absorption (REA nanocolor microfluidic devices are new promising bioassay platforms, which employ nanoparticle- (NP- protein conjugates for the immunodetection of medically relevant markers in biologic samples such as blood, urine, and saliva. The core component of a REA test device is a PET chip coated with aluminum and SiO2 thin layers, onto which biorecognitive molecules are immobilized. Upon addition of a sample containing the analyte of interest, a NP-protein-analyte complex is formed in the test device that is captured on the REA chip, for example, via streptavidin-biotin interaction. Thereby, a colored symbol is generated, which allows optical readout. Silver enhancement of the bound nanoparticles may be used to increase the sensitivity of the assay. Herein, we demonstrate that adsorptive immobilization via a cationic polymeric interlayer is a competitive and fast technique for the binding of the capture protein streptavidin onto planar SiO2 surfaces such as REA biochips. Moreover, we report the development of a silver enhancement technology that operates even in the presence of high chloride concentrations as may be encountered in biologic samples. The silver enhancement reagents may be integrated into the microfluidic assay platform to be released upon sample addition. Hereby, a highly sensitive one-step assay can be realized.

  3. Performing chemical reactions in virtual capillary of surface tension-confined microfluidic devices

    Indian Academy of Sciences (India)

    Angshuman Nag; Biswa Ranjan Panda; Arun Chattopadhyay

    2005-10-01

    In this paper we report a new method of fabrication of surface tension-confined microfluidic devices on glass. We have also successfully carried out some well-known chemical reactions in these fluidic channels to demonstrate the usefulness of these wall-less microchannels. The confined flow path of liquid was achieved on the basis of extreme differences in hydrophobic and hydrophilic characters of the surface. The flow paths were fabricated by making parallel lines using permanent marker pen ink or other polymer on glass surfaces. Two mirror image patterned glass plates were then sandwiched one on top of the other, separated by a thin gap - created using a spacer. The aqueous liquid moves between the surfaces by capillary forces, confined to the hydrophilic areas without wetting the hydrophobic lines, achieving liquid confinement without physical side-walls. We have shown that the microfluidic devices designed in such a way can be very useful due to their simplicity and low fabrication cost. More importantly, we have also demonstrated that the minimum requirement of such a working device is a hydrophilic line surrounded by hydrophobic environment, two walls of which are constituted of air and the rest is made of a hydrophobic surface.

  4. High-stringency screening of target-binding partners using a microfluidic device

    Energy Technology Data Exchange (ETDEWEB)

    Soh, Hyongsok; Lou, Xinhui; Lagally, Eric

    2015-12-01

    The invention provides a method of screening a library of candidate agents by contacting the library with a target in a reaction mixture under a condition of high stringency, wherein the target includes a tag that responds to a controllable force applied to the tag, and passing the members of the library through a microfluidic device in a manner that exposes the library members to the controllable force, thereby displacing members of the library that are bound to the target relative to their unbound counterparts. Kits and systems for use with the methods of the invention are also provided.

  5. Micro-chemical synthesis of molecular probes on an electronic microfluidic device

    OpenAIRE

    Keng, Pei Yuin; Chen, Supin; Ding, Huijiang; Sadeghi, Saman; Shah, Gaurav J.; Dooraghi, Alex; Michael E. Phelps; Satyamurthy, Nagichettiar; Chatziioannou, Arion F; Kim, Chang-Jin “CJ”; van Dam, R. Michael

    2011-01-01

    We have developed an all-electronic digital microfluidic device for microscale chemical synthesis in organic solvents, operated by electrowetting-on-dielectric (EWOD). As an example of the principles, we demonstrate the multistep synthesis of [18F]FDG, the most common radiotracer for positron emission tomography (PET), with high and reliable radio-fluorination efficiency of [18F]FTAG (88 ± 7%, n = 11) and quantitative hydrolysis to [18F]FDG (> 95%, n = 11). We furthermore show that batches of...

  6. Simulation of the Cystic Fibrosis patient airway habitats using microfluidic devices

    DEFF Research Database (Denmark)

    Skolimowski, Maciej

    2013-01-01

    affecting human airways is cystic fibrosis. Cystic fibrosis (CF) patients suffer from a genetic defect that influences the salt transport over the cell membranes. Due to this effect, the mucus layer becomes very viscous as the defect in salt transport inhibit diffusion of and establishment of the important...... of treating infections in CF patients. Therefore, in this work we propose novel microfluidic devices that on one hand can mimic different airway environments by controlling the oxygen levels and on the other hand can mimic the microenvironment of the cystic fibrosis bronchi....

  7. A Disposable Microfluidic Device with a Screen Printed Electrode for Mimicking Phase II Metabolism

    Science.gov (United States)

    Vasiliadou, Rafaela; Nasr Esfahani, Mohammad Mehdi; Brown, Nathan J.; Welham, Kevin J.

    2016-01-01

    Human metabolism is investigated using several in vitro methods. However, the current methodologies are often expensive, tedious and complicated. Over the last decade, the combination of electrochemistry (EC) with mass spectrometry (MS) has a simpler and a cheaper alternative to mimic the human metabolism. This paper describes the development of a disposable microfluidic device with a screen-printed electrode (SPE) for monitoring phase II GSH reactions. The proposed chip has the potential to be used as a primary screening tool, thus complementing the current in vitro methods. PMID:27598162

  8. Novel Polymer Microfluidics Technology for In Situ Planetary Exploration Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Los Gatos Research proposes to develop a novel microfluidic device that combines rigid monolithic porous polymer based micro-capillary electrochromatography...

  9. Flow control using audio tones in resonant microfluidic networks: towards cell-phone controlled lab-on-a-chip devices.

    Science.gov (United States)

    Phillips, Reid H; Jain, Rahil; Browning, Yoni; Shah, Rachana; Kauffman, Peter; Dinh, Doan; Lutz, Barry R

    2016-08-16

    Fluid control remains a challenge in development of portable lab-on-a-chip devices. Here, we show that microfluidic networks driven by single-frequency audio tones create resonant oscillating flow that is predicted by equivalent electrical circuit models. We fabricated microfluidic devices with fluidic resistors (R), inductors (L), and capacitors (C) to create RLC networks with band-pass resonance in the audible frequency range available on portable audio devices. Microfluidic devices were fabricated from laser-cut adhesive plastic, and a "buzzer" was glued to a diaphragm (capacitor) to integrate the actuator on the device. The AC flowrate magnitude was measured by imaging oscillation of bead tracers to allow direct comparison to the RLC circuit model across the frequency range. We present a systematic build-up from single-channel systems to multi-channel (3-channel) networks, and show that RLC circuit models predict complex frequency-dependent interactions within multi-channel networks. Finally, we show that adding flow rectifying valves to the network creates pumps that can be driven by amplified and non-amplified audio tones from common audio devices (iPod and iPhone). This work shows that RLC circuit models predict resonant flow responses in multi-channel fluidic networks as a step towards microfluidic devices controlled by audio tones. PMID:27416111

  10. Flow control using audio tones in resonant microfluidic networks: towards cell-phone controlled lab-on-a-chip devices.

    Science.gov (United States)

    Phillips, Reid H; Jain, Rahil; Browning, Yoni; Shah, Rachana; Kauffman, Peter; Dinh, Doan; Lutz, Barry R

    2016-08-16

    Fluid control remains a challenge in development of portable lab-on-a-chip devices. Here, we show that microfluidic networks driven by single-frequency audio tones create resonant oscillating flow that is predicted by equivalent electrical circuit models. We fabricated microfluidic devices with fluidic resistors (R), inductors (L), and capacitors (C) to create RLC networks with band-pass resonance in the audible frequency range available on portable audio devices. Microfluidic devices were fabricated from laser-cut adhesive plastic, and a "buzzer" was glued to a diaphragm (capacitor) to integrate the actuator on the device. The AC flowrate magnitude was measured by imaging oscillation of bead tracers to allow direct comparison to the RLC circuit model across the frequency range. We present a systematic build-up from single-channel systems to multi-channel (3-channel) networks, and show that RLC circuit models predict complex frequency-dependent interactions within multi-channel networks. Finally, we show that adding flow rectifying valves to the network creates pumps that can be driven by amplified and non-amplified audio tones from common audio devices (iPod and iPhone). This work shows that RLC circuit models predict resonant flow responses in multi-channel fluidic networks as a step towards microfluidic devices controlled by audio tones.

  11. A ferrofluid guided system for the rapid separation of the non-magnetic particles in a microfluidic device.

    Science.gov (United States)

    Asmatulu, R; Zhang, B; Nuraje, N

    2010-10-01

    A microfluidic device was fabricated via UV lithography technique to separate non-magnetic fluoresbrite carboxy microspheres (approximately 4.5 microm) in the pH 7 ferrofluids made of magnetite nanoparticles (approximately 10 nm). A mixture of microspheres and ferrofluid was injected to a lithographically developed Y shape microfluidic device, and then by applying the external magnet fields (0.45 T), the microspheres were clearly separated into different channels because of the magnetic force acting on those non-magnetic particles. During this study, various pumping speeds and particle concentrations associated with the various distances between the magnet and the microfluidic device were investigated for an efficient separation. This study may be useful for the separation of biological particles, which are very sensitive to pH value of the solutions. PMID:21137734

  12. Integrated Microfluidic System for Size-Based Selection and Trapping of Giant Vesicles.

    Science.gov (United States)

    Kazayama, Yuki; Teshima, Tetsuhiko; Osaki, Toshihisa; Takeuchi, Shoji; Toyota, Taro

    2016-01-19

    Vesicles composed of phospholipids (liposomes) have attracted interest as artificial cell models and have been widely studied to explore lipid-lipid and lipid-protein interactions. However, the size dispersity of liposomes prepared by conventional methods was a major problem that inhibited their use in high-throughput analyses based on monodisperse liposomes. In this study, we developed an integrative microfluidic device that enables both the size-based selection and trapping of liposomes. This device consists of hydrodynamic selection and trapping channels in series, which made it possible to successfully produce an array of more than 60 monodisperse liposomes from a polydisperse liposome suspension with a narrow size distribution (the coefficient of variation was less than 12%). We successfully observed a size-dependent response of the liposomes to sequential osmotic stimuli, which had not clarified so far, by using this device. Our device will be a powerful tool to facilitate the statistical analysis of liposome dynamics.

  13. Quasi-Optical Terahertz Microfluidic Devices for Chemical Sensing and Imaging

    OpenAIRE

    Lei Liu; Zhenguo Jiang; Syed (Shawon) Rahman; Md. Itrat Bin Shams; Benxin Jing; Akash Kannegulla; Li-Jing Cheng

    2016-01-01

    We first review the development of a frequency domain quasi-optical terahertz (THz) chemical sensing and imaging platform consisting of a quartz-based microfluidic subsystem in our previous work. We then report the application of this platform to sensing and characterizing of several selected liquid chemical samples from 570–630 GHz. THz sensing of chemical mixtures including isopropylalcohol-water (IPA-H2O) mixtures and acetonitrile-water (ACN-H2O) mixtures have been successfully demonstrate...

  14. Comprehensive study of an optical fiber plasmonic microsensor in a microfluidic device

    OpenAIRE

    2011-01-01

    Abstract In the last decade, surface plasmon resonance (SPR) has become a very sensitive technique for real-time detection of chemical and biochemical targets in many application areas. Considering the important needs for analyzing biomolecular reactions through automated and miniaturized components, optical fiber sensors based on the SPR effects are presently considered as an alternative in the development of microsensors. In the present work, a microfluidic system associated with...

  15. Comprehensive study of an optical fiber plasmonic microsensor in a microfluidic device

    OpenAIRE

    Makiabadi, T.; Le Nader, V.; Kanso, M.; Louarn, G.

    2011-01-01

    International audience In the last decade, surface plasmon resonance (SPR) has become a very sensitive technique for real-time detection of chemical and biochemical targets in many application areas. Considering the important needs for analyzing biomolecular reactions through automated and miniaturized components, optical fiber sensors based on the SPR effects are presently considered as an alternative in the development of microsensors. In the present work, a microfluidic system associate...

  16. Out-of-focus effects on microscale schlieren measurements of mass transport in a microfluidic device

    Science.gov (United States)

    Chen, Shao-Tuan; Sun, Chen-li

    2016-08-01

    The microscale schlieren technique provides a means for a non-invasive, full-field measurement for mixing microfluidics with excellent sensitivity and resolution. Nevertheless, an out-of-focus effect due to microscopic optics may lead to undesirable errors in quantifying the gradient information at high degrees of magnification. If the channel in the microfluidic device under study is too deep, light deflection caused by inhomogeneity located far from the focal plane may contributes little to the intensity change on the image plane. To address this issue, we propose the use of a weighting function that approximates a Gaussian profile with an optical-system-dependable width. We assume that the resultant intensity change is proportional to a weighted sum of the gradient across the channel depth and acquire micro-schlieren images of fluid mixing in a T-junction microchannel at various positions along the optical axis. For each objective, the width of the weighting function is then determined iteratively by curve fitting the ratio of changes in grayscale readouts for out-of-focus and focus micro-schlieren images. The standard deviation in the Gaussian distribution facilitates the quantification of the out-of-focus effect. In addition, we measure the sensitivities of a microscale schlieren system equipped with different objectives and compare the values to the model. Despite its better resolution, we find that an objective with higher magnification suffers from a more severe out-of-focus effect and a loss of sensitivity. Equations are proposed for estimations of the standard deviation and the sensitivity of microscale schlieren measurements. The outcome will facilitate the selection of proper microchannel depths for various microscale schlieren systems or vice versa, thus improving the precision of micro-schlieren measurements in microfluidic devices.

  17. Microfluidic enzymatic DNA extraction on a hybrid polyester-toner-PMMA device.

    Science.gov (United States)

    Thompson, Brandon L; Birch, Christopher; Li, Jingyi; DuVall, Jacquelyn A; Le Roux, Delphine; Nelson, Daniel A; Tsuei, An-Chi; Mills, Daniel L; Krauss, Shannon T; Root, Brian E; Landers, James P

    2016-08-01

    To date, the forensic community regards solid phase extraction (SPE) as the most effective methodology for the purification of DNA for use in short tandem repeat (STR) polymerase chain reaction (PCR) amplification. While a dominant methodology, SPE protocols generally necessitate the use of PCR inhibitors (guanidine, IPA) and, in addition, can demand timescales of up to 30 min due to the necessary load, wash and elution steps. The recent discovery and characterization of the EA1 protease has allowed the user to enzymatically extract (not purify) DNA, dramatically simplifying the task of producing a PCR-ready template. Despite this, this procedure has yet to make a significant impact on microfluidic technologies. Here, we describe a microfluidic device that implements the EA1 enzyme for DNA extraction by incorporating it into a hybrid microdevice comprising laminated polyester (Pe) and PMMA layers. The PMMA layer provides a macro-to-micro interface for introducing the biological sample into the microfluidic architecture, whilst also possessing the necessary dimensions to function as the swab acceptor. Pre-loaded reagents are then introduced to the swab chamber centrifugally, initiating DNA extraction at 75 °C. The extraction of DNA occurs in timescales of less than 3 min and any external hardware associated with the transportation of reagents by pneumatic pumping is eliminated. Finally, multiplexing is demonstrated with a circular device containing eight separate chambers for the simultaneous processing of eight buccal swab samples. The studies here provide DNA concentrations up to 10 ng μL(-1) with a 100% success rate in less than 3 minutes. The STR profiles generated using these extracted samples demonstrate that the DNA is of PCR forensic-quality and adequate for human identification. PMID:27250903

  18. Electric Characterization and Modeling of Microfluidic-Based Dye-Sensitized Solar Cell

    Directory of Open Access Journals (Sweden)

    Adriano Sacco

    2012-01-01

    Full Text Available The electric response to an external periodic voltage of small amplitude of dye-sensitized solar cells (DSCs made up with an alternative architecture has been investigated. DSCs have been fabricated with a reversible sealing structure, based on microfluidic concepts, with a precise control on the geometric parameters of the active chamber. Cells with different electrolyte thicknesses have been characterized, without varying the thickness of the TiO2 layer, both under illumination and in dark conditions. Measurements of the electric impedance have been performed in the presence of an external bias ranging from 0 V to 0.8 V. The experimental data have been analyzed in terms of a transmission line model, with two transport channels. The results show that the photovoltaic performances of the microfluidic cell are comparable with those obtained in irreversibly sealed structures, actually demonstrating the reliability of the proposed device.

  19. DNA sequence analysis with droplet-based microfluidics

    OpenAIRE

    Abate, Adam R.; Hung, Tony; Sperling, Ralph A.; Mary, Pascaline; Rotem, Assaf; Agresti, Jeremy J.; Weiner, Michael A.; Weitz, David A.

    2013-01-01

    Droplet-based microfluidic techniques can form and process micrometer scale droplets at thousands per second. Each droplet can house an individual biochemical reaction, allowing millions of reactions to be performed in minutes with small amounts of total reagent. This versatile approach has been used for engineering enzymes, quantifying concentrations of DNA in solution, and screening protein crystallization conditions. Here, we use it to read the sequences of DNA molecules with a FRET-based ...

  20. 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.

  1. An optimised detector for in-situ high-resolution NMR in microfluidic devices

    Science.gov (United States)

    Finch, Graeme; Yilmaz, Ali; Utz, Marcel

    2016-01-01

    Integration of high-resolution nuclear magnetic resonance (NMR) spectroscopy with microfluidic lab-on-a-chip devices is challenging due to limited sensitivity and line broadening caused by magnetic susceptibility inhomogeneities. We present a novel double-stripline NMR probe head that accommodates planar microfluidic devices, and obtains the NMR spectrum from a rectangular sample chamber on the chip with a volume of 2 μ l. Finite element analysis was used to jointly optimise the detector and sample volume geometry for sensitivity and RF homogeneity. A prototype of the optimised design has been built, and its properties have been characterised experimentally. The performance in terms of sensitivity and RF homogeneity closely agrees with the numerical predictions. The system reaches a mass limit of detection of 1.57 nmol √{ s } , comparing very favourably with other micro-NMR systems. The spectral resolution of this chip/probe system is better than 1.75 Hz at a magnetic field of 7 T, with excellent line shape.

  2. 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.

  3. Crystallization Kinetics of Partially Crystalline Emulsion Droplets in a Microfluidic Device.

    Science.gov (United States)

    Prileszky, Tamás A; Furst, Eric M

    2016-05-24

    We measure the crystallization kinetics of petrolatum-hexadecane emulsion droplets as they are produced in a microfluidic device. After droplets form, they are cooled, causing an interior network of wax crystallites to grow. Polarized light microscopy is used to quantify the droplet crystallinity as a function of residence time in the device. Two wavelengths and two polarization orientations are used to decouple the wavelength dependence of the optical retardation, the crystallite orientation, and the crystallite number density. The droplet crystallinity follows the Avrami kinetic model with parameter values in agreement with the theoretically expected values. These results provide a means to engineer the crystallization kinetics, stability, and arrested coalescence of partially crystalline emulsion droplets. PMID:27137839

  4. A High Power-Density Mediator-Free Microfluidic Biophotovoltaic Device for Cyanobacterial Cells

    CERN Document Server

    Bombelli, Paolo; Herling, Therese W; Howe, Christopher J; Knowles, Tuomas P J

    2014-01-01

    Biophotovoltaics has emerged as a promising technology for generating renewable energy since it relies on living organisms as inexpensive, self-repairing and readily available catalysts to produce electricity from an abundant resource - sunlight. The efficiency of biophotovoltaic cells, however, has remained significantly lower than that achievable through synthetic materials. Here, we devise a platform to harness the large power densities afforded by miniaturised geometries. To this effect, we have developed a soft-lithography approach for the fabrication of microfluidic biophotovoltaic devices that do not require membranes or mediators. Synechocystis sp. PCC 6803 cells were injected and allowed to settle on the anode, permitting the physical proximity between cells and electrode required for mediator-free operation. We demonstrate power densities of above 100 mW/m2 for a chlorophyll concentration of 100 {\\mu}M under white light, a high value for biophotovoltaic devices without extrinsic supply of additional...

  5. Challenges in the Use of Compact Disc-Based Centrifugal Microfluidics for Healthcare Diagnostics at the Extreme Point of Care

    Directory of Open Access Journals (Sweden)

    Jordon Gilmore

    2016-03-01

    Full Text Available Since its inception, Compact Disc (CD-based centrifugal microfluidic technology has drawn a great deal of interest within research communities due to its potential use in biomedical applications. The technology has been referred to by different names, including compact-disc microfluidics, lab-on-a-disk, lab-on-a-CD and bio-disk. This paper critically reviews the state-of-the-art in CD-based centrifugal microfluidics devices and attempts to identify the challenges that, if solved, would enable their use in the extreme point of care. Sample actuation, manufacturing, reagent storage and implementation, target multiplexing, bio-particle detection, required hardware and system disposal, and sustainability are the topics of focus.

  6. 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. PMID:22939509

  7. Inexpensive, rapid prototyping of microfluidic devices using overhead transparencies and a laser print, cut and laminate fabrication method.

    Science.gov (United States)

    Thompson, Brandon L; Ouyang, Yiwen; Duarte, Gabriela R M; Carrilho, Emanuel; Krauss, Shannon T; Landers, James P

    2015-06-01

    We describe a technique for fabricating microfluidic devices with complex multilayer architectures using a laser printer, a CO2 laser cutter, an office laminator and common overhead transparencies as a printable substrate via a laser print, cut and laminate (PCL) methodology. The printer toner serves three functions: (i) it defines the microfluidic architecture, which is printed on the overhead transparencies; (ii) it acts as the adhesive agent for the bonding of multiple transparency layers; and (iii) it provides, in its unmodified state, printable, hydrophobic 'valves' for fluidic flow control. By using common graphics software, e.g., CorelDRAW or AutoCAD, the protocol produces microfluidic devices with a design-to-device time of ∼40 min. Devices of any shape can be generated for an array of multistep assays, with colorimetric detection of molecular species ranging from small molecules to proteins. Channels with varying depths can be formed using multiple transparency layers in which a CO2 laser is used to remove the polyester from the channel sections of the internal layers. The simplicity of the protocol, availability of the equipment and substrate and cost-effective nature of the process make microfluidic devices available to those who might benefit most from expedited, microscale chemistry. PMID:25974096

  8. Biologically-inspired Microfluidic Platforms and Aptamer-based Nanobiosensors

    OpenAIRE

    Cho, Hansang

    2010-01-01

    Recent advances in micro/nano- technologies have shown high potentials in the field of quantitative biology, biomedical science, and analytical chemistry. However, micro/nano fluidics still requires multi-layered structures, complex plumbing/tubing, and external equipments for large-scale applications and nanotechnology-based sensors demand high cost. Interestingly, nature has much simpler and more effective solutions. The goal of this dissertation is to develop novel microfluidic platforms a...

  9. Effect of gold nanoparticles on thermal gradient generation and thermotaxis of E. coli cells in microfluidic device.

    Science.gov (United States)

    Murugesan, Nithya; Panda, Tapobrata; Das, Sarit K

    2016-08-01

    Bacteria responds to changing chemical and thermal environment by moving towards or away from a particular location. In this report, we looked into thermal gradient generation and response of E. coli DH5α cells to thermal gradient in the presence and in the absence of spherical gold nanoparticles (size: 15 to 22 nm) in a static microfluidic environment using a polydimethylsiloxane (PDMS) made microfluidic device. A PDMS-agarose based microfluidic device for generating thermal gradient has been developed and the thermal gradient generation in the device has been validated with the numerical simulation. Our studies revealed that the presence of gold nanoparticles, AuNPs (0.649 μg/mL) has no effect on the thermal gradient generation. The E. coli DH5α cells have been treated with AuNPs of two different concentrations (0.649 μg/mL and 0.008 μg/mL). The thermotaxis behavior of cells in the presence of AuNPs has been studied and compared to the thermotaxis of E.coli DH5α cells in the absence of AuNPs. In case of thermotaxis, in the absence of the AuNPs, the E. coli DH5α cells showed better thermotaxis towards lower temperature range, whereas in the presence of AuNPs (0.649 μg/mL and 0.008 μg/mL) thermotaxis of the E. coli DH5α cells has been inhibited. The results show that the spherical AuNPs intervenes in the themotaxis of E. coli DH5α cells and inhibits the cell migration. The reason for the failure in thermotaxis response mechanism may be due to decreased F-type ATP synthase activity and collapse of membrane potential by AuNPs, which, in turn, leads to decreased ATP levels. This has been hypothesized since both thermotaxis and chemotaxis follows the same response mechanism for migration in which ATP plays critical role. PMID:27246690

  10. One-step patterning of hollow microstructures in paper by laser cutting to create microfluidic analytical devices.

    Science.gov (United States)

    Nie, Jinfang; Liang, Yuanzhi; Zhang, Yun; Le, Shangwang; Li, Dunnan; Zhang, Songbai

    2013-01-21

    In this paper, we report a simple, low-cost method for rapid, highly reproductive fabrication of paper-based microfluidics by using a commercially available, minitype CO(2) laser cutting/engraving machine. This method involves only one operation of cutting a piece of paper by laser according to a predesigned pattern. The hollow microstructures formed in the paper are used as the 'hydrophobic barriers' to define the hydrophilic flowing paths. A typical paper device on a 4 cm × 4 cm piece of paper can be fabricated within ∼7-20 s; it is ready for use once the cutting process is finished. The main fabrication parameters such as the applied current and cutting rate of the laser were optimized. The fabrication resolution and multiplexed analytical capability of the hollow microstructure-patterned paper were also characterized.

  11. 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

  12. A Laminated Microfluidic Device for Comprehensive Preclinical Testing in the Drug ADME Process.

    Science.gov (United States)

    An, Fan; Qu, Yueyang; Luo, Yong; Fang, Ning; Liu, Yang; Gao, Zhigang; Zhao, Weijie; Lin, Bingcheng

    2016-01-01

    New techniques are urgently needed to replace conventional long and costly pre-clinical testing in the new drug administration process. In this study, a laminated microfluidic device was fabricated to mimic the drug ADME response test in vivo. This proposed device was loaded and cultured with functional cells for drug response investigation and organ tissues that are involved in ADME testing. The drug was introduced from the top of the device and first absorbed by the Caco-2 cell layer, and then metabolized by the primary hepatocyte layer. It subsequently interacted with the MCF-7 cell layer, distributed in the lung, heart and fat tissues, and was finally eliminated through the dialysis membrane. Throughout this on-chip ADME process, the proposed device can be used as a reliable tool to simultaneously evaluate the drug anti-tumor activity, hepatotoxicity and pharmacokinetics. Furthermore, this device was proven to be able to reflect the hepatic metabolism of a drug, drug distribution in the target tissues, and the administration method of a drug. Furthermore, this microdevice is expected to reduce the number of drug candidates and accelerate the pre-clinical testing process subject to animal testing upon adaptation in new drug discovery. PMID:27122192

  13. Development of microfluidic devices for in situ investigation of cells using surface-enhanced Raman spectroscopy (Conference Presentation)

    Science.gov (United States)

    Ho, Yu-Han; Galvan, Daniel D.; Yu, Qiuming

    2016-03-01

    Surface-enhanced Raman spectroscopy (SERS) has immerged as a power analytical and sensing technique for many applications in biomedical diagnosis, life sciences, food safety, and environment monitoring because of its molecular specificity and high sensitivity. The inactive Raman scattering of water molecule makes SERS a suitable tool for studying biological systems. Microfluidic devices have also attracted a tremendous interest for the aforementioned applications. By integrating SERS-active substrates with microfluidic devices, it offers a new capability for in situ investigation of biological systems, their dynamic behaviors, and response to drugs or microenvironment changes. In this work, we designed and fabricated a microfluidic device with SERS-active substrates surrounding by cell traps in microfluidic channels for in situ study of live cells using SERS. The SERS-active substrates are quasi-3D plasmonic nanostructure array (Q3D-PNA) made in h-PDMS/PMDS with physically separated gold film with nanoholes op top and gold nanodisks at the bottom of nanowells. 3D finite-difference time-domain (3D-FDTD) electromagnetic simulations were performed to design Q3D-PNAs with the strongest local electric fields (hot spots) at the top or bottom water/Au interfaces for sensitive analysis of cells and small components, respectively. The Q3D-PNAs with the hot spots on top and bottom were placed at the up and down stream of the microfluidic channel, respectively. Each Q3D-PNA pattern was surrounded with cell trapping structures. The microfluidic device was fabricated via soft lithography. We demonstrated that normal (COS-7) and cancer (HpeG2) cells were captured on the Q3D-PNAs and investigated in situ using SERS.

  14. Integrated cantilever-based flow sensors with tunable sensitivity for in-line monitoring of flow fluctuations in microfluidic systems

    DEFF Research Database (Denmark)

    Noeth, Nadine-Nicole; Keller, Stephan Sylvest; Boisen, Anja

    2014-01-01

    For devices such as bio-/chemical sensors in microfluidic systems, flow fluctuations result in noise in the sensor output. Here, we demonstrate in-line monitoring of flow fluctuations with a cantilever-like sensor integrated in a microfluidic channel. The cantilevers are fabricated in different m...... pumps connected to the microfluidic system. © 2013 by the authors; licensee MDPI, Basel, Switzerland....

  15. Generation and functional assessment of 3D multicellular spheroids in droplet based microfluidics platform.

    Science.gov (United States)

    Sabhachandani, P; Motwani, V; Cohen, N; Sarkar, S; Torchilin, V; Konry, T

    2016-02-01

    Here we describe a robust, microfluidic technique to generate and analyze 3D tumor spheroids, which resembles tumor microenvironment and can be used as a more effective preclinical drug testing and screening model. Monodisperse cell-laden alginate droplets were generated in polydimethylsiloxane (PDMS) microfluidic devices that combine T-junction droplet generation and external gelation for spheroid formation. The proposed approach has the capability to incorporate multiple cell types. For the purposes of our study, we generated spheroids with breast cancer cell lines (MCF-7 drug sensitive and resistant) and co-culture spheroids of MCF-7 together with a fibroblast cell line (HS-5). The device has the capability to house 1000 spheroids on chip for drug screening and other functional analysis. Cellular viability of spheroids in the array part of the device was maintained for two weeks by continuous perfusion of complete media into the device. The functional performance of our 3D tumor models and a dose dependent response of standard chemotherapeutic drug, doxorubicin (Dox) and standard drug combination Dox and paclitaxel (PCT) was analyzed on our chip-based platform. Altogether, our work provides a simple and novel, in vitro platform to generate, image and analyze uniform, 3D monodisperse alginate hydrogel tumors for various omic studies and therapeutic efficiency screening, an important translational step before in vivo studies. PMID:26686985

  16. A rapid, straightforward, and print house compatible mass fabrication method for integrating 3D paper-based microfluidics.

    Science.gov (United States)

    Xiao, Liangpin; Liu, Xianming; Zhong, Runtao; Zhang, Kaiqing; Zhang, Xiaodi; Zhou, Xiaomian; Lin, Bingcheng; Du, Yuguang

    2013-11-01

    Three-dimensional (3D) paper-based microfluidics, which is featured with high performance and speedy determination, promise to carry out multistep sample pretreatment and orderly chemical reaction, which have been used for medical diagnosis, cell culture, environment determination, and so on with broad market prospect. However, there are some drawbacks in the existing fabrication methods for 3D paper-based microfluidics, such as, cumbersome and time-consuming device assembly; expensive and difficult process for manufacture; contamination caused by organic reagents from their fabrication process. Here, we present a simple printing-bookbinding method for mass fabricating 3D paper-based microfluidics. This approach involves two main steps: (i) wax-printing, (ii) bookbinding. We tested the delivery capability, diffusion rate, homogeneity and demonstrated the applicability of the device to chemical analysis by nitrite colorimetric assays. The described method is rapid (print house, making itself an ideal scheme for large-scale production of 3D paper-based microfluidics.

  17. RNA Extraction from a Mycobacterium under Ultrahigh Electric Field Intensity in a Microfluidic Device.

    Science.gov (United States)

    Ma, Sai; Bryson, Bryan D; Sun, Chen; Fortune, Sarah M; Lu, Chang

    2016-05-17

    Studies of transcriptomes are critical for understanding gene expression. Release of RNA molecules from cells is typically the first step for transcriptomic analysis. Effective cell lysis approaches that completely release intracellular materials are in high demand especially for cells that are structurally robust. In this report, we demonstrate a microfluidic electric lysis device that is effective for mRNA extraction from mycobacteria that have hydrophobic and waxy cell walls. We used a packed bed of microscale silica beads to filter M. smegmatis out of the suspension. 4000-8000 V/cm field intensity was used to lyse M. smegmatis with long pulses (i.e., up to 30 pulses that were 5 s long each). Our quantitative reverse transcription (qRT)-PCR results showed that our method yielded a factor of 10-20 higher extraction efficiency than the current state-of-the-art method (bead beating). We conclude that our electric lysis technique is an effective approach for mRNA release from hard-to-lyse cells and highly compatible with microfluidic molecular assays. PMID:27081872

  18. Highly efficient adenoviral transduction of pancreatic islets using a microfluidic device.

    Science.gov (United States)

    Silva, Pamuditha N; Atto, Zaid; Regeenes, Romario; Tufa, Uilki; Chen, Yih Yang; Chan, Warren C W; Volchuk, Allen; Kilkenny, Dawn M; Rocheleau, Jonathan V

    2016-08-01

    Tissues are challenging to genetically manipulate due to limited penetration of viral particles resulting in low transduction efficiency. We are particularly interested in expressing genetically-encoded sensors in ex vivo pancreatic islets to measure glucose-stimulated metabolism, however poor viral penetration biases these measurements to only a subset of cells at the periphery. To increase mass transfer of viral particles, we designed a microfluidic device that holds islets in parallel hydrodynamic traps connected by an expanding by-pass channel. We modeled viral particle flow into the tissue using fluorescently-labelled gold nanoparticles of varying sizes and showed a penetration threshold of only ∼5 nm. To increase this threshold, we used EDTA to transiently reduce cell-cell adhesion and expand intercellular space. Ultimately, a combination of media flow and ETDA treatment significantly increased adenoviral transduction to the core of the islet. As proof-of-principle, we used this protocol to transduce an ER-targeted redox sensitive sensor (eroGFP), and revealed significantly greater ER redox capacity at core islet cells. Overall, these data demonstrate a robust method to enhance transduction efficiency of islets, and potentially other tissues, by using a combination of microfluidic flow and transient tissue expansion. PMID:27378588

  19. Self-regenerating and hybrid irreversible/reversible PDMS microfluidic devices

    Science.gov (United States)

    Shiroma, Letícia S.; Piazzetta, Maria H. O.; Duarte-Junior, Gerson F.; Coltro, Wendell K. T.; Carrilho, Emanuel; Gobbi, Angelo L.; Lima, Renato S.

    2016-05-01

    This paper outlines a straightforward, fast, and low-cost method to fabricate polydimethylsiloxane (PDMS) chips. Termed sandwich bonding (SWB), this method requires only a laboratory oven. Initially, SWB relies on the reversible bonding of a coverslip over PDMS channels. The coverslip is smaller than the substrate, leaving a border around the substrate exposed. Subsequently, a liquid composed of PDMS monomers and a curing agent is poured onto the structure. Finally, the cover is cured. We focused on PDMS/glass chips because of their key advantages in microfluidics. Despite its simplicity, this method created high-performance microfluidic channels. Such structures featured self-regeneration after leakages and hybrid irreversible/reversible behavior. The reversible nature was achieved by removing the cover of PDMS with acetone. Thus, the PDMS substrate and glass coverslip could be detached for reuse. These abilities are essential in the stages of research and development. Additionally, SWB avoids the use of surface oxidation, half-cured PDMS as an adhesive, and surface chemical modification. As a consequence, SWB allows surface modifications before the bonding, a long time for alignment, the enclosure of sub-micron channels, and the prototyping of hybrid devices. Here, the technique was successfully applied to bond PDMS to Au and Al.

  20. In situ fabrication of a microfluidic device for immobilised metal affinity sensing.

    Science.gov (United States)

    Deshpande, Abhishek G; Darton, Nicholas J; Yunus, Kamran; Fisher, Adrian C; Slater, Nigel K H

    2012-05-15

    In this work a novel microfluidic device was constructed in situ containing the smallest microscopic co-polymeric immobilised metal affinity (IMA) adsorbent yet documented. This device has for the first time allowed the microlitre scale chromatographic assay of histidine-tagged proteins in a biological sample. To enable this approach, rather than using a high capacity commercial packed bed column which requires large sample volumes and would be susceptible to occlusion by cell debris, a microgram capacity co-polymeric chromatographic substrate suitable for analytical applications was fabricated within a microfluidic channel. This porous co-polymeric IMA micro-chromatographic element, only 27μl in volume, was assessed for the analytical capture of two different histidine-tagged recombinant fusion proteins. The micro-chromatographic adsorber was fabricated in situ by photo-polymerising an iminodiacetic acid (IDA) functionalised polymer matrix around a template of fused 100μm diameter NH(4)Cl particles entirely within the microfluidic channel and then etching away the salt with water to form a network of interconnected voids. The surface of the micro-chromatographic adsorber was chemically functionalised with a chelating agent and loaded with Cu(2+) ions. FTIR and NMR analysis verified the presence of the chelating agent on the adsorbent surface and its Cu(2+) ion binding capacity was determined to be 2.4μmol Cu(2+) (ml of adsorbent)(-1). Micro-scale equilibrium adsorption studies using the two different histidine-tagged proteins, LacI-His(6)-GFP and α-Synuclein-His(8)-YFP, were carried out and the protein binding capacity of the adsorbent was determined to be 0.370 and 0.802mg(g of adsorbent)(-1), respectively. The dynamic binding capacity was determined at four different flow rates and found to be comparable to the equilibrium binding capacity at low flow rates. The sensing platform was also used to adsorb LacI-His(6)-GFP protein from crude cell lysate. During

  1. Microfluidic actuation of insulating liquid droplets in a parallel-plate device

    International Nuclear Information System (INIS)

    In droplet-based microfluidics, the simultaneous movement and manipulation of dielectric and aqueous droplets on a single platform is important. The actuation forces on both dielectric and aqueous droplets can be calculated with an electromechanical model using an equivalent RC circuit. This model predicts that dielectric droplet actuation can be made compatible with electrowetting-based water droplet manipulation if the oil droplet is immersed in water. Operations such as transporting, splitting, merging, and dispensing of dielectric droplets at voltages less than 100 V are demonstrated in a parallel-plate structure. Such capability opens the way to fully automated assembly line formation of single-emulsion droplets.

  2. Quantum dot-based microfluidic biosensor for cancer detection

    Science.gov (United States)

    Ghrera, Aditya Sharma; Pandey, Chandra Mouli; Ali, Md. Azahar; Malhotra, Bansi Dhar

    2015-05-01

    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 10-15 M to 10-11 M.

  3. Production of Fluconazole-Loaded Polymeric Micelles Using Membrane and Microfluidic Dispersion Devices

    Science.gov (United States)

    Lu, Yu; Chowdhury, Danial; Vladisavljević, Goran T.; Koutroumanis, Konstantinos; Georgiadou, Stella

    2016-01-01

    Polymeric micelles with a controlled size in the range between 41 and 80 nm were prepared by injecting the organic phase through a microengineered nickel membrane or a tapered-end glass capillary into an aqueous phase. The organic phase was composed of 1 mg·mL−1 of PEG-b-PCL diblock copolymers with variable molecular weights, dissolved in tetrahydrofuran (THF) or acetone. The pore size of the membrane was 20 μm and the aqueous/organic phase volumetric flow rate ratio ranged from 1.5 to 10. Block copolymers were successfully synthesized with Mn ranging from ~9700 to 16,000 g·mol−1 and polymeric micelles were successfully produced from both devices. Micelles produced from the membrane device were smaller than those produced from the microfluidic device, due to the much smaller pore size compared with the orifice size in a co-flow device. The micelles were found to be relatively stable in terms of their size with an initial decrease in size attributed to evaporation of residual solvent rather than their structural disintegration. Fluconazole was loaded into the cores of micelles by injecting the organic phase composed of 0.5–2.5 mg·mL−1 fluconazole and 1.5 mg·mL−1 copolymer. The size of the drug-loaded micelles was found to be significantly larger than the size of empty micelles. PMID:27231945

  4. Production of Fluconazole-Loaded Polymeric Micelles Using Membrane and Microfluidic Dispersion Devices

    Directory of Open Access Journals (Sweden)

    Yu Lu

    2016-05-01

    Full Text Available Polymeric micelles with a controlled size in the range between 41 and 80 nm were prepared by injecting the organic phase through a microengineered nickel membrane or a tapered-end glass capillary into an aqueous phase. The organic phase was composed of 1 mg·mL−1 of PEG-b-PCL diblock copolymers with variable molecular weights, dissolved in tetrahydrofuran (THF or acetone. The pore size of the membrane was 20 μm and the aqueous/organic phase volumetric flow rate ratio ranged from 1.5 to 10. Block copolymers were successfully synthesized with Mn ranging from ~9700 to 16,000 g·mol−1 and polymeric micelles were successfully produced from both devices. Micelles produced from the membrane device were smaller than those produced from the microfluidic device, due to the much smaller pore size compared with the orifice size in a co-flow device. The micelles were found to be relatively stable in terms of their size with an initial decrease in size attributed to evaporation of residual solvent rather than their structural disintegration. Fluconazole was loaded into the cores of micelles by injecting the organic phase composed of 0.5–2.5 mg·mL−1 fluconazole and 1.5 mg·mL−1 copolymer. The size of the drug-loaded micelles was found to be significantly larger than the size of empty micelles.

  5. Stimuli-responsive materials: developing integrated opto-molecular systems as sensors and actuators in micro-fluidic devices

    OpenAIRE

    Florea, Larisa

    2013-01-01

    Micro-fluidic platforms have been conferred with inherent optical sensing capabilities by coating the walls of micro-fluidic channels or micro-capillaries with stimuli-responsive materials. These adaptive materials respond optically to environmental stimuli, such as changes in pH, solvent polarity, the presence of certain metal ions and light. This approach confers sensing capabilities along the entire length of the coated micro-channel or micro-capillary. Adaptive coatings based on two types...

  6. 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.

  7. Experimental evidence of slippage breakdown for a superhydrophobic surface in a microfluidic device

    CERN Document Server

    Bolognesi, Guido; Pirat, Christophe

    2014-01-01

    A full characterization of the water flow past a silicon superhydrophobic surface with longitudinal micro-grooves enclosed in a microfluidic device is presented. Fluorescence microscopy images of the flow seeded with fluorescent passive tracers were digitally processed to measure both the velocity field and the position and shape of the liquid-air interfaces at the superhydrophobic surface. The simultaneous access to the meniscus and velocity profiles allows us to put under a strict test the no-shear boundary condition at the liquid-air interface. Surprisingly, our measurements show that air pockets in the surface cavities can sustain non-zero interfacial shear stresses, thereby hampering the friction reduction capabilities of the surface. The effects of the meniscus position and shape as well as of the liquid-air interfacial friction on the surface performances are separately assessed and quantified.

  8. Measurement of buried undercut structures in microfluidic devices by laser fluorescent confocal microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Li Shiguang; Liu Jing; Nguyen, Nam-Trung; Fang Zhongping; Yoon, Soon Fatt

    2009-11-20

    Measuring buried, undercut microstructures is a challenging task in metrology. These structures are usually characterized by measuring their cross sections after physically cutting the samples. This method is destructive and the obtained information is incomplete. The distortion due to cutting also affects the measurement accuracy. In this paper, we first apply the laser fluorescent confocal microscopy and intensity differentiation algorithm to obtain the complete three-dimensional profile of the buried, undercut structures in microfluidic devices, which are made by the soft lithography technique and bonded by the oxygen plasma method. The impact of material wettability and the refractive index (n) mismatch among the liquid, samples, cover layer, and objective on the measurement accuracy are experimentally investigated.

  9. A microfluidic device for practical label-free CD4+ T cell counting of HIV-infected subjects

    OpenAIRE

    Cheng, Xuanhong; Irimia, Daniel; Dixon, Meredith; Sekine, Kazuhiko; Demirci, Utkan; Zamir, Lee; Tompkins, Ronald G.; Rodriguez, William; Toner, Mehmet

    2006-01-01

    Practical HIV diagnostics are urgently needed in resource-limited settings. While HIV infection can be diagnosed using simple, rapid, lateral flow immunoassays, HIV disease staging and treatment monitoring require accurate counting of a particular white blood cell subset, the CD4+ T lymphocyte. To address the limitations of current expensive, technically demanding and/or time-consuming approaches, we have developed a simple CD4 counting microfluidic device. This device uses cell affinity chro...

  10. Flexible free-standing SU-8 microfluidic impedance spectroscopy sensor for 3-D molded interconnect devices application

    OpenAIRE

    Schmidt, Marc-Peter; Oseev, Aleksandr; Engel, Christian; Brose, Andreas; Schmidt, Bertram; Hirsch, Sören

    2016-01-01

    The current contribution reports about the fabrication technology for the development of novel microfluidic impedance spectroscopy sensors that are directly attachable on 3-D molded interconnect devices (3D-MID) that provides an opportunity to create reduced-scale sensor devices for 3-D applications. Advantages of the MID technology in particular for an automotive industry application were recently discussed (Moser and Krause, 2006). An ability to integrate electrical and fluid...

  11. Microfluidic application-specific integrated device for monitoring direct cell-cell communication via gap junctions between individual cell pairs

    Science.gov (United States)

    Lee, Philip J.; Hung, Paul J.; Shaw, Robin; Jan, Lily; Lee, Luke P.

    2005-05-01

    Direct cell-cell communication between adjacent cells is vital for the development and regulation of functional tissues. However, current biological techniques are difficult to scale up for high-throughput screening of cell-cell communication in an array format. In order to provide an effective biophysical tool for the analysis of molecular mechanisms of gap junctions that underlie intercellular communication, we have developed a microfluidic device for selective trapping of cell-pairs and simultaneous optical characterizations. Two different cell populations can be brought into membrane contact using an array of trapping channels with a 2μm by 2μm cross section. Device operation was verified by observation of dye transfer between mouse fibroblasts (NIH3T3) placed in membrane contact. Integration with lab-on-a-chip technologies offers promising applications for cell-based analytical tools such as drug screening, clinical diagnostics, and soft-state biophysical devices for the study of gap junction protein channels in cellular communications. Understanding electrical transport mechanisms via gap junctions in soft membranes will impact quantitative biomedical sciences as well as clinical applications.

  12. Microfluidic gradient device for studying mesothelial cell migration and the effect of chronic carbon nanotube exposure

    International Nuclear Information System (INIS)

    Cell migration is one of the crucial steps in many physiological and pathological processes, including cancer development. Our recent studies have shown that carbon nanotubes (CNTs), similarly to asbestos, can induce accelerated cell growth and invasiveness that contribute to their mesothelioma pathogenicity. Malignant mesothelioma is a very aggressive tumor that develops from cells of the mesothelium, and is most commonly caused by exposure to asbestos. CNTs have a similar structure and mode of exposure to asbestos. This has raised a concern regarding the potential carcinogenicity of CNTs, especially in the pleural area which is a key target for asbestos-related diseases. In this paper, a static microfluidic gradient device was applied to study the migration of human pleural mesothelial cells which had been through a long-term exposure (4 months) to subcytotoxic concentration (0.02 µg cm−2) of single-walled CNTs (SWCNTs). Multiple migration signatures of these cells were investigated using the microfluidic gradient device for the first time. During the migration study, we observed that cell morphologies changed from flattened shapes to spindle shapes prior to their migration after their sensing of the chemical gradient. The migration of chronically SWCNT-exposed mesothelial cells was evaluated under different fetal bovine serum (FBS) concentration gradients, and the migration speeds and number of migrating cells were extracted and compared. The results showed that chronically SWCNT-exposed mesothelial cells are more sensitive to the gradient compared to non-SWCNT-exposed cells. The method described here allows simultaneous detection of cell morphology and migration under chemical gradient conditions, and also allows for real-time monitoring of cell motility that resembles in vivo cell migration. This platform would be much needed for supporting the development of more physiologically relevant cell models for better assessment and characterization of the

  13. Microfluidic gradient device for studying mesothelial cell migration and the effect of chronic carbon nanotube exposure

    Science.gov (United States)

    Zhang, Hanyuan; Lohcharoenkal, Warangkana; Sun, Jianbo; Li, Xiang; Wang, Liying; Wu, Nianqiang; Rojanasakul, Yon; Liu, Yuxin

    2016-01-01

    Cell migration is one of the crucial steps in many physiological and pathological processes, including cancer development. Our recent studies have shown that carbon nanotubes (CNTs), similarly to asbestos, can induce accelerated cell growth and invasiveness that contribute to their mesothelioma pathogenicity. Malignant mesothelioma is a very aggressive tumor that develops from cells of the mesothelium, and is most commonly caused by exposure to asbestos. CNTs have a similar structure and mode of exposure to asbestos. This has raised a concern regarding the potential carcinogenicity of CNTs, especially in the pleural area which is a key target for asbestos-related diseases. In this paper, a static microfluidic gradient device was applied to study the migration of human pleural mesothelial cells which had been through a long-term exposure (4 months) to subcytotoxic concentration (0.02 μg cm−2) of single-walled CNTs (SWCNTs). Multiple migration signatures of these cells were investigated using the microfluidic gradient device for the first time. During the migration study, we observed that cell morphologies changed from flattened shapes to spindle shapes prior to their migration after their sensing of the chemical gradient. The migration of chronically SWCNT-exposed mesothelial cells was evaluated under different fetal bovine serum (FBS) concentration gradients, and the migration speeds and number of migrating cells were extracted and compared. The results showed that chronically SWCNT-exposed mesothelial cells are more sensitive to the gradient compared to non-SWCNT-exposed cells. The method described here allows simultaneous detection of cell morphology and migration under chemical gradient conditions, and also allows for real-time monitoring of cell motility that resembles in vivo cell migration. This platform would be much needed for supporting the development of more physiologically relevant cell models for better assessment and characterization of the

  14. IFSA: a microfluidic chip-platform for frit-based immunoassay protocols

    Science.gov (United States)

    Hlawatsch, Nadine; Bangert, Michael; Miethe, Peter; Becker, Holger; Gärtner, Claudia

    2013-03-01

    Point-of-care diagnostics (POC) is one of the key application fields for lab-on-a-chip devices. While in recent years much of the work has concentrated on integrating complex molecular diagnostic assays onto a microfluidic device, there is a need to also put comparatively simple immunoassay-type protocols on a microfluidic platform. In this paper, we present the development of a microfluidic cartridge using an immunofiltration approach. In this method, the sandwich immunoassay takes place in a porous frit on which the antibodies have immobilized. The device is designed to be able to handle three samples in parallel and up to four analytical targets per sample. In order to meet the critical cost targets for the diagnostic market, the microfluidic chip has been designed and manufactured using high-volume manufacturing technologies in mind. Validation experiments show comparable sensitivities in comparison with conventional immunofiltration kits.

  15. DNA sequence analysis with droplet-based microfluidics

    Science.gov (United States)

    Abate, Adam R.; Hung, Tony; Sperling, Ralph A.; Mary, Pascaline; Rotem, Assaf; Agresti, Jeremy J.; Weiner, Michael A.; Weitz, David A.

    2014-01-01

    Droplet-based microfluidic techniques can form and process micrometer scale droplets at thousands per second. Each droplet can house an individual biochemical reaction, allowing millions of reactions to be performed in minutes with small amounts of total reagent. This versatile approach has been used for engineering enzymes, quantifying concentrations of DNA in solution, and screening protein crystallization conditions. Here, we use it to read the sequences of DNA molecules with a FRET-based assay. Using probes of different sequences, we interrogate a target DNA molecule for polymorphisms. With a larger probe set, additional polymorphisms can be interrogated as well as targets of arbitrary sequence. PMID:24185402

  16. Confined chemiluminescence detection of nanomolar levels of H2O2 in a paper-plastic disposable microfluidic device using a smartphone.

    Science.gov (United States)

    Lebiga, Elise; Edwin Fernandez, Renny; Beskok, Ali

    2015-08-01

    We report the design and characterization of a disposable light shielded paper-plastic microfluidic device that can detect nanomolar levels of H2O2 using a smartphone camera and a light sealed accessory. Chemiluminescence reaction of H2O2 with bis(2,4,6-trichlorophenyl)oxalate in the presence of rubrene and imidazole is confined to a paper reaction site where the individual reagents are delivered via plastic microfluidic channels. The net photon emission from the chemiluminescence reactions, detected by using a smartphone, is correlated with H2O2 concentrations. With a total reagent volume of 25 μL, the sensor system was able to detect H2O2 concentrations as low as 250 nM. The smartphone based chemiluminescence sensing system has great potential as a point of care diagnostic tool for monitoring nanomolar levels of H2O2 in biological samples. PMID:26057240

  17. A microfluidic device for 2D to 3D and 3D to 3D cell navigation

    International Nuclear Information System (INIS)

    Microfluidic devices have received wide attention and shown great potential in the field of tissue engineering and regenerative medicine. Investigating cell response to various stimulations is much more accurate and comprehensive with the aid of microfluidic devices. In this study, we introduced a microfluidic device by which the matrix density as a mechanical property and the concentration profile of a biochemical factor as a chemical property could be altered. Our microfluidic device has a cell tank and a cell culture chamber to mimic both 2D to 3D and 3D to 3D migration of three types of cells. Fluid shear stress is negligible on the cells and a stable concentration gradient can be obtained by diffusion. The device was designed by a numerical simulation so that the uniformity of the concentration gradients throughout the cell culture chamber was obtained. Adult neural cells were cultured within this device and they showed different branching and axonal navigation phenotypes within varying nerve growth factor (NGF) concentration profiles. Neural stem cells were also cultured within varying collagen matrix densities while exposed to NGF concentrations and they experienced 3D to 3D collective migration. By generating vascular endothelial growth factor concentration gradients, adult human dermal microvascular endothelial cells also migrated in a 2D to 3D manner and formed a stable lumen within a specific collagen matrix density. It was observed that a minimum absolute concentration and concentration gradient were required to stimulate migration of all types of the cells. This device has the advantage of changing multiple parameters simultaneously and is expected to have wide applicability in cell studies. (paper)

  18. A microfluidic device for 2D to 3D and 3D to 3D cell navigation

    Science.gov (United States)

    Shamloo, Amir; Amirifar, Leyla

    2016-01-01

    Microfluidic devices have received wide attention and shown great potential in the field of tissue engineering and regenerative medicine. Investigating cell response to various stimulations is much more accurate and comprehensive with the aid of microfluidic devices. In this study, we introduced a microfluidic device by which the matrix density as a mechanical property and the concentration profile of a biochemical factor as a chemical property could be altered. Our microfluidic device has a cell tank and a cell culture chamber to mimic both 2D to 3D and 3D to 3D migration of three types of cells. Fluid shear stress is negligible on the cells and a stable concentration gradient can be obtained by diffusion. The device was designed by a numerical simulation so that the uniformity of the concentration gradients throughout the cell culture chamber was obtained. Adult neural cells were cultured within this device and they showed different branching and axonal navigation phenotypes within varying nerve growth factor (NGF) concentration profiles. Neural stem cells were also cultured within varying collagen matrix densities while exposed to NGF concentrations and they experienced 3D to 3D collective migration. By generating vascular endothelial growth factor concentration gradients, adult human dermal microvascular endothelial cells also migrated in a 2D to 3D manner and formed a stable lumen within a specific collagen matrix density. It was observed that a minimum absolute concentration and concentration gradient were required to stimulate migration of all types of the cells. This device has the advantage of changing multiple parameters simultaneously and is expected to have wide applicability in cell studies.

  19. “Flow valve” microfluidic devices for simple, detectorless and label-free analyte quantitation

    Science.gov (United States)

    Chatterjee, Debolina; Mansfield, Danielle S.; Anderson, Neil G.; Subedi, Sudeep; Woolley, Adam T.

    2012-01-01

    Simplified analysis systems that offer the performance of benchtop instruments but the convenience of portability are highly desirable. We have developed novel, miniature devices that feature visual inspection readout of a target’s concentration from a ~1 μL volume of solution introduced into a microfluidic channel. Microchannels are constructed within an elastomeric material, and channel surfaces are coated with receptors to the target. When a solution is flowed into the channel, the target crosslinks multiple receptors on the surface, resulting in constriction of the first few millimeters of the channel and stopping of flow. Quantitation is performed by measuring the distance traveled by the target solution in the channel before flow stops. A key advantage of our approach is that quantitation is accomplished by simple visual inspection of the channel, without the need for complex detection instrumentation. We have tested these devices using the model system of biotin as a receptor and streptavidin as the target. We have also characterized three factors that influence flow distance: solution viscosity, device thickness, and channel height. We found that solution capillary flow distance scales with the negative logarithm of target concentration and have detected streptavidin concentrations as low as 1 ng/mL. Finally, we have identified and evaluated a plausible mechanism wherein time-dependent channel constriction in the first few millimeters leads to concentration-dependent flow distances. Their simplicity coupled with performance makes these “flow valve” systems especially attractive for a host of analysis applications. PMID:22881075

  20. Direct current insulator based dielectrophoresis (DC-iDEP) microfluidic chip for blood plasma separation

    OpenAIRE

    Mohammadi, Mahdi

    2015-01-01

    Lab-on-a-Chip (LOC) integrated microfluidics has been a powerful tool for new developments in analytical chemistry. These microfluidic systems enable the miniaturization, integration and automation of complex biochemical assays through the reduction of reagent use and enabling portability.Cell and particle separation in microfluidic systems has recently gained significant attention in many sample preparations for clinical procedures. Direct-current insulator-based dielectrophoresis (DC-iDEP) ...

  1. Microfluidic waves.

    Science.gov (United States)

    Utz, Marcel; Begley, Matthew R; Haj-Hariri, Hossein

    2011-11-21

    The propagation of pressure waves in fluidic channels with elastic covers is discussed in view of applications to flow control in microfluidic devices. A theory is presented which describes pressure waves in the fluid that are coupled to bending waves in the elastic cover. At low frequencies, the lateral bending of the cover dominates over longitudinal bending, leading to propagating, non-dispersive longitudinal pressure waves in the channel. The theory addresses effects due to both the finite viscosity and compressibility of the fluid. The coupled waves propagate without dispersion, as long as the wave length is larger than the channel width. It is shown that in channels of typical microfluidic dimensions, wave velocities in the range of a few 10 m s(-1) result if the channels are covered by films of a compliant material such as PDMS. The application of this principle to design microfluidic band pass filters based on standing waves is discussed. Characteristic frequencies in the range of a few kHz are readily achieved with quality factors above 30. PMID:21966667

  2. PMMA to Polystyrene bonding for polymer based microfluidic systems

    KAUST Repository

    Fan, Yiqiang

    2013-03-29

    A thermal bonding technique for Poly (methylmethacrylate) (PMMA) to Polystyrene (PS) is presented in this paper. The PMMA to PS bonding was achieved using a thermocompression method, and the bonding strength was carefully characterized. The bonding temperature ranged from 110 to 125 C with a varying compression force, from 700 to 1,000 N (0.36-0.51 MPa). After the bonding process, two kinds of adhesion quantification methods were used to measure the bonding strength: the double cantilever beam method and the tensile stress method. The results show that the bonding strength increases with a rising bonding temperature and bonding force. The results also indicate that the bonding strength is independent of bonding time. A deep-UV surface treatment method was also provided in this paper to lower the bonding temperature and compression force. Finally, a PMMA to PS bonded microfluidic device was fabricated successfully. © 2013 Springer-Verlag Berlin Heidelberg.

  3. 3D imaging of flow patterns in an internally-pumped microfluidic device: redox magnetohydrodynamics and electrochemically-generated density gradients.

    Science.gov (United States)

    Gao, Feng; Kreidermacher, Adam; Fritsch, Ingrid; Heyes, Colin D

    2013-05-01

    Redox magnetohydrodynamics (MHD) is a promising technique for developing new electrochemical-based microfluidic flow devices with unique capabilities, such as easily switching flow direction and adjusting flow speeds and flow patterns as well as avoiding bubble formation. However, a detailed description of all the forces involved and predicting flow patterns in confined geometries is lacking. In addition to redox-MHD, density gradients caused by the redox reactions also play important roles. Flow in these devices with small fluid volumes has mainly been characterized by following microbead motion by optical microscopy either by particle tracking velocimetry (PTV) or by processing the microbead images by particle image velocimetry (PIV) software. This approach has limitations in spatial resolution and dimensionality. Here we use fluorescence correlation spectroscopy (FCS) to quantitatively and accurately measure flow speeds and patterns in the ~5-50 μm/s range in redox-MHD-based microfluidic devices, from which 3D flow maps are obtained with a spatial resolution down to 2 μm. The 2 μm spatial resolution flow speeds map revealed detailed flow profiles during redox-MHD in which the velocity increases linearly from above the electrode and reaches a plateau across the center of the cell. By combining FCS and video-microscopy (with PTV and PIV processing approaches), we are able to quantify a vertical flow of ~10 μm/s above the electrodes as a result of density gradients caused by the redox reactions and follow convection flow patterns. Overall, combining FCS, PIV, and PTV analysis of redox-MHD is a powerful combination to more thoroughly characterize the underlying forces in these promising microfluidic devices. PMID:23537496

  4. A continuous glucose monitoring device by graphene modified electrochemical sensor in microfluidic system.

    Science.gov (United States)

    Pu, Zhihua; Zou, Chongwei; Wang, Ridong; Lai, Xiaochen; Yu, Haixia; Xu, Kexin; Li, Dachao

    2016-01-01

    This paper presents a continuous glucose monitoring microsystem consisting of a three-electrode electrochemical sensor integrated into a microfluidic chip. The microfluidic chip, which was used to transdermally extract and collect subcutaneous interstitial fluid, was fabricated from five polydimethylsiloxane layers using micromolding techniques. The electrochemical sensor was integrated into the chip for continuous detection of glucose. Specifically, a single-layer graphene and gold nanoparticles (AuNPs) were decorated onto the working electrode (WE) of the sensor to construct a composite nanostructured surface and improve the resolution of the glucose measurements. Graphene was transferred onto the WE surface to improve the electroactive nature of the electrode to enable measurements of low levels of glucose. The AuNPs were directly electrodeposited onto the graphene layer to improve the electron transfer rate from the activity center of the enzyme to the electrode to enhance the sensitivity of the sensor. Glucose oxidase (GOx) was immobilized onto the composite nanostructured surface to specifically detect glucose. The factors required for AuNPs deposition and GOx immobilization were also investigated, and the optimized parameters were obtained. The experimental results displayed that the proposed sensor could precisely measure glucose in the linear range from 0 to 162 mg/dl with a detection limit of 1.44 mg/dl (S/N = 3). The proposed sensor exhibited the potential to detect hypoglycemia which is still a major challenge for continuous glucose monitoring in clinics. Unlike implantable glucose sensors, the wearable device enabled external continuous monitoring of glucose without interference from foreign body reaction and bioelectricity.

  5. Attenuated total reflection-Fourier transform infrared spectroscopic imaging of pharmaceuticals in microfluidic devices.

    Science.gov (United States)

    Ewing, Andrew V; Clarke, Graham S; Kazarian, Sergei G

    2016-03-01

    The poor aqueous solubility of many active pharmaceutical ingredients presents challenges for effective drug delivery. In this study, the combination of attenuated total reflection (ATR)-FTIR spectroscopic imaging with specifically designed polydimethylsiloxane microfluidic devices to study drug release from pharmaceutical formulations has been developed. First, the high-throughput analysis of the dissolution of micro-formulations studied under flowing conditions has been introduced using a model formulation of ibuprofen and polyethylene glycol. The behaviour and release of the drug was monitored in situ under different pH conditions. In contrast to the neutral solution, where both the drug and excipient dissolved at a similar rate, structural change from the molecularly dispersed to a crystalline form of ibuprofen was characterised in the obtained spectroscopic images and the corresponding ATR-FTIR spectra for the experiments carried out in the acidic medium. Further investigations into the behaviour of the drug after its release from formulations (i.e., dissolved drug) were also undertaken. Different solutions of sodium ibuprofen dissolved in a neutral medium were studied upon contact with acidic conditions. The phase transition from a dissolved species of sodium ibuprofen to the formation of solid crystalline ibuprofen was revealed in the microfluidic channels. This innovative approach could offer a promising platform for high-throughput analysis of a range of micro-formulations, which are of current interest due to the advent of 3D printed pharmaceutical and microparticulate delivery systems. Furthermore, the ability to study dissolved drug in solution under flowing conditions can be useful for the studies of the diffusion of drugs into tissues or live cells. PMID:27158293

  6. A microfluidic device for the automated electrical readout of low-density glass-slide microarrays.

    Science.gov (United States)

    Díaz-González, María; Salvador, J Pablo; Bonilla, Diana; Marco, M Pilar; Fernández-Sánchez, César; Baldi, Antoni

    2015-12-15

    Microarrays are a powerful platform for rapid and multiplexed analysis in a wide range of research fields. Electrical readout systems have emerged as an alternative to conventional optical methods for microarray analysis thanks to its potential advantages like low-cost, low-power and easy miniaturization of the required instrumentation. In this work an automated electrical readout system for low-cost glass-slide microarrays is described. The system enables the simultaneous conductimetric detection of up to 36 biorecognition events by incorporating an array of interdigitated electrode transducers. A polydimethylsiloxane microfluidic structure has been designed that creates microwells over the transducers and incorporates the microfluidic channels required for filling and draining them with readout and cleaning solutions, thus making the readout process fully automated. Since the capture biomolecules are not immobilized on the transducer surface this readout system is reusable, in contrast to previously reported electrochemical microarrays. A low-density microarray based on a competitive enzymatic immunoassay for atrazine detection was used to test the performance of the readout system. The electrical assay shows a detection limit of 0.22±0.03 μg L(-1) similar to that obtained with fluorescent detection and allows the direct determination of the pesticide in polluted water samples. These results proved that an electrical readout system such as the one presented in this work is a reliable and cost-effective alternative to fluorescence scanners for the analysis of low-density microarrays.

  7. Rapid identification of ESKAPE bacterial strains using an autonomous microfluidic device.

    Directory of Open Access Journals (Sweden)

    Jack Y Ho

    Full Text Available This article describes Bacteria ID Chips ('BacChips': an inexpensive, portable, and autonomous microfluidic platform for identifying pathogenic strains of bacteria. BacChips consist of a set of microchambers and channels molded in the elastomeric polymer, poly(dimethylsiloxane (PDMS. Each microchamber is preloaded with mono-, di-, or trisaccharides and dried. Pressing the layer of PDMS into contact with a glass coverslip forms the device; the footprint of the device in this article is ∼6 cm(2. After assembly, BacChips are degased under large negative pressure and are stored in vacuum-sealed plastic bags. To use the device, the bag is opened, a sample containing bacteria is introduced at the inlet of the device, and the degased PDMS draws the sample into the central channel and chambers. After the liquid at the inlet is consumed, air is drawn into the BacChip via the inlet and provides a physical barrier that separates the liquid samples in adjacent microchambers. A pH indicator is admixed with the samples prior to their loading, enabling the metabolism of the dissolved saccharides in the microchambers to be visualized. Importantly, BacChips operate without external equipment or instruments. By visually detecting the growth of bacteria using ambient light after ∼4 h, we demonstrate that BacChips with ten microchambers containing different saccharides can reproducibly detect the ESKAPE panel of pathogens, including strains of: Enterococcus faecalis, Enteroccocus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, Enterobacter aerogenes, and Enterobacter cloacae. This article describes a BacChip for point-of-care detection of ESKAPE pathogens and a starting point for designing multiplexed assays that identify bacterial strains from clinical samples and simultaneously determine their susceptibility to antibiotics.

  8. Analytical optimization of nanocomposite surface-enhanced Raman spectroscopy/scattering detection in microfluidic separation devices.

    Science.gov (United States)

    Connatser, R Maggie; Cochran, Malcolm; Harrison, Robert J; Sepaniak, Michael J

    2008-04-01

    Adding vibrational spectroscopies to the arsenal of detection modes for microfluidics (mufluidics) offers benefits afforded by structurally descriptive identification of separated electrophoretic bands. We have previously applied surface-enhanced Raman spectroscopy (SERS) detection with nanocomposite metal-elastomer substrates as a detection mode in mufluidic channels. To create these mufluidic-SERS devices, silver-PDMS substrate regions are integrated into the architecture of a separation chip fabricated from PDMS or glass. Herein, we investigate analytical figures of merit for integrated mufluidic-SERS devices by implementing improvements in fluidic and SERS substrate fabrication as well as data collection strategies. Improvements are achieved by chemical modification of the PDMS channel, increasing effective detection efficiency by minimizing analyte partitioning into nonsensing walls rendering more analyte available to the metallized cover slide of channels and also by uniquely fabricating deep channels that have larger volume to SERS surface area ratios than conventional channels. A method is developed to exploit the inherent concentration profile of analyte material within an electrophoretic band in order to extend the linear dynamic range of detection on the SERS nanostructured surface. This is accomplished by spatially interrogating the Gaussian concentration profile of said bands. The subtleties of this technique give insight into the analytical utility of SERS detection in general. Finally, SERS substrates uniquely created via electron beam lithography with controllable morphologies are integrated into mufluidic-SERS devices to prove feasibility of such a coupling for future work. A separation of endocrine disrupting chemicals in a hybrid SERS nanocomposite-glass device is the capstone of this work. PMID:18386301

  9. Behavior of Caulobacter Crescentus Diagnosed Using a 3-Channel Microfluidic Device

    Science.gov (United States)

    Tang, Jay; Morse, Michael; Colin, Remy; Wilson, Laurence

    2015-03-01

    Many motile microorganisms are able to detect chemical gradients in their surroundings in order to bias their motion towards more favorable conditions. We study the biased motility of Caulobacter crescentus, a singly flagellated bacteria, which alternate between forward and backward swimming, driven by its flagella motor, which switches in rotation direction. We observe the swimming patterns of C. crescents in an oxygen gradient, which is established by flowing atmospheric air and pure nitrogen through a 3 parallel channel microfluidic device. In this setup, oxygen diffuses through the PDMS device and the bacterial medium, creating a linear gradient. Using low magnification, dark field microscopy, individual cells are tracked over a large field of view, with particular interest in the cells' motion relative to the oxygen gradient. Utilizing observable differences between backward and forward swimming motion, motor switching events can be identified. By analyzing these run time intervals between motor switches as a function of a cell's local oxygen level, we demonstrate that C. crescentus displays aerotacitc behavior by extending forward swimming run times while moving up an oxygen gradient, resulting in directed motility towards oxygen sources. Additionally, motor switching response is sensitive to both the steepness of the gradient experienced and background oxygen levels with cells exhibiting a logarithmic response to oxygen levels. Work funded by the United States National Science Foundation and by the Rowland Institute at Harvard University.

  10. Inkjet patterned superhydrophobic paper for open-air surface microfluidic devices.

    Science.gov (United States)

    Elsharkawy, Mohamed; Schutzius, Thomas M; Megaridis, Constantine M

    2014-03-21

    We present a facile approach for the fabrication of low-cost surface biomicrofluidic devices on superhydrophobic paper created by drop-casting a fluoroacrylic copolymer onto microtextured paper. Wettability patterning is performed with a common household printer, which produces regions of varying wettability by simply controlling the intensity of ink deposited over prespecified domains. The procedure produces surfaces that are capable of selective droplet sliding and adhesion, when inclined. Using this methodology, we demonstrate the ability to tune the sliding angles of 10 μL water droplets in the range from 13° to 40° by printing lines of constant ink intensity and varied width from 0.1 mm to 2 mm. We also formulate a simple model to predict the onset of droplet sliding on printed lines of known width and wettability. Experiments demonstrate open-air surface microfluidic devices that are capable of pumpless transport, mixing and rapid droplet sampling (~0.6 μL at 50 Hz). Lastly, post treatment of printed areas with pH indicator solutions exemplifies the utility of these substrates in point-of-care diagnostics, which are needed at geographical locations where access to sophisticated testing equipment is limited or non-existent.

  11. Microfluidic devices for imaging neurological response of Drosophila melanogaster larva to auditory stimulus.

    Science.gov (United States)

    Ghaemi, Reza; Rezai, Pouya; Iyengar, Balaji G; Selvaganapathy, Ponnambalam Ravi

    2015-02-21

    Two microfluidic devices (pneumatic chip and FlexiChip) have been developed for immobilization and live-intact fluorescence functional imaging of Drosophila larva's Central Nervous System (CNS) in response to controlled acoustic stimulation. The pneumatic chip is suited for automated loading/unloading and potentially allows high throughput operation for studies with a large number of larvae while the FlexiChip provides a simple and quick manual option for animal loading and is suited for smaller studies. Both chips were capable of significantly reducing the endogenous CNS movement while still allowing the study of sound-stimulated CNS activities of Drosophila 3rd instar larvae using genetically encoded calcium indicator GCaMP5. Temporal effects of sound frequency (50-5000 Hz) and intensity (95-115 dB) on CNS activities were investigated and a peak neuronal response of 200 Hz was identified. Our lab-on-chip devices can not only aid further studies of Drosophila larva's auditory responses but can be also adopted for functional imaging of CNS activities in response to other sensory cues. Auditory stimuli and the corresponding response of the CNS can potentially be used as a tool to study the effect of chemicals on the neurophysiology of this model organism.

  12. A miniature quantitative PCR device for directly monitoring a sample processing on a microfluidic rapid DNA system.

    Science.gov (United States)

    Hurth, Cedric; Yang, Jianing; Barrett, Matthew; Brooks, Carla; Nordquist, Alan; Smith, Stanley; Zenhausern, Frederic

    2014-12-01

    We report a microfluidic device and measurement method to perform real-time PCR (or qPCR) in a miniaturized configuration for on-chip implementation using reaction volumes of less than 20 μL. The qPCR bioreactor is designed as a module to be embedded in an automated sample-in/profile-out system for rapid DNA biometrics or human identification. The PCR mixture is excited with a 505 nm diode-pumped solid-state laser (DPSSL) and the fluorescence build-up is measured using optical fibers directly embedded to the sidewalls of the microfluidic qPCR bioreactor. We discuss manufacturing and operating parameters necessary to adjust the internal surface conditions and temperature profiles of the bioreactor and to optimize the yield and quality of the PCR reaction for the amplification of 62 bp hTERT intron fragments using the commercial Quantifiler® kit (Life Technologies, Carlsbad, CA) commonly accepted for genotyping analysis. We designed a microfluidic device suitable for continuously processing a specimen by efficiently mixing the reagents from the kit to a set volume of DNA template on chip. Our approach relies on a calibration curve for the specific device using control DNA. We successfully applied this method to determine the concentration of genomic DNA extracted from a buccal swab on separate microfluidic devices which are operated upstream the qPCR device and perform buccal swab lysis and buccal DNA extraction. A precise correlation between the amount determined on chip and that obtained using a commercial cycler is demonstrated.

  13. Microfluidic platforms for gallium-based liquid metal alloy

    Science.gov (United States)

    Kim, Daeyoung

    As an alternative to toxic mercury, non-toxic gallium-based liquid metal alloy has been gaining popularity due to its higher thermal and electrical conductivities, and low toxicity along with liquid property. However, it is difficult to handle as the alloy becomes readily oxidized in atmospheric air environment. This instant oxidation causes the gallium-based liquid metal alloy to wet almost any solid surface. Therefore, it has been primarily limited to applications which rely only on its deformability, not on its mobility. In this research, various approaches to mobilize gallium-based liquid metal alloy were investigated. Multi-scale surface patterned with polydimethylsiloxane (PDMS) micro pillar array showed super-lyophobic property against gallium-based liquid metal alloy by minimizing the contact area between the solid surface and the liquid metal, and it was expanded to a three-dimensional tunnel shaped microfluidic channel. Vertically-aligned carbon nanotube forest leads to another promising super-lyophobic surface due to its hierarchical micro/nano scale combined structures and chemical inertness. When the carbon nanotubes were transferred onto flexible PDMS by imprinting, the super-lyophobic property was still maintained even under the mechanical deformation such as stretching and bending. Alternatively, the gallium-based liquid metal can be manipulated by modifying the surface of liquid metal itself. With chemical reaction with HCl 'vapor', the oxidized surface (mainly Ga2O3/Ga2O) of gallium-based liquid metal was converted to GaCl3/InCl 3 resulting in the recovery of non-wetting characteristics. Paper which is intrinsically porous is attractive as a super-lyophobic surface and it was found that hydrochloric acid (HCl) impregnation enhanced the anti-wetting property by the chemical reaction. As another alternative method, by coating the viscoelastic oxidized surface of liquid metal with ferromagnetic materials (CoNiMnP or Fe), it showed non

  14. Microfluidic Analytical Separator for Proteomics Project

    Data.gov (United States)

    National Aeronautics and Space Administration — SHOT proposes an innovative microfluidic device designed to effect a 2-dimensional resolution of a mixture of proteins based on isoelectric point (pI) and molecular...

  15. Microfluidic Analytical Separator for Proteomics Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The proposed innovation is a microfluidic device designed to effect a 2-dimensional resolution of a mixture of proteins based on isoelectric point (pI) and...

  16. A novel temperature control method for shortening thermal cycling time to achieve rapid polymerase chain reaction (PCR) in a disposable polymer microfluidic device

    DEFF Research Database (Denmark)

    Bu, Minqiang; R. Perch-Nielsen, Ivan; Sørensen, Karen Skotte;

    We present a new temperature control method capable of effectively shortening the thermal cycling time of polymerase chain reaction (PCR) in a disposable polymer microfluidic device with external heater and temperature sensor. The method employs optimized temperature overshooting and undershooting...

  17. Investigation of Dendrimer-based nanoparticles cellular uptake and cell tracking in a semiautomated microfluidic platform

    OpenAIRE

    Carvalho, Mariana Rodrigues; Maia, Fátima Raquel; Reis, R. L.; Oliveira, J. M.

    2016-01-01

    A microfluidic device such as Kima Pump and Vena8 biochip is able to realize functions that are not easily imaginable in conventional biological analysis, such as highly parallel, sophisticated high-throughput analysis and single-cell analysis in a well-defined manner [1]. Cancer cell tracking within the microfluidic model will be achieved by grafting fluorescent label probe Fluorescein-5(6)-isothiocyanate (FITC) to dendrimer nanoparticles allowing cell visualization by immunofluorescen...

  18. A Digitally Controllable Polymer-Based Microfluidic Mixing Module Array

    Directory of Open Access Journals (Sweden)

    Raymond H. W. Lam

    2012-03-01

    Full Text Available This paper presents an integrated digitally controllable microfluidic system for continuous solution supply with a real-time concentration control. This system contains multiple independently operating mixing modules, each integrated with two vortex micropumps, two Tesla valves and a micromixer. The interior surface of the system is made of biocompatible materials using a polymer micro-fabrication process and thus its operation can be applied to chemicals and bio-reagents. In each module, pumping of fluid is achieved by the vortex micropump working with the rotation of a micro-impeller. The downstream fluid mixing is based on mechanical vibrations driven by a lead zirconate titanate ceramic diaphragm actuator located below the mixing chamber. We have conducted experiments to prove that the addition of the micro-pillar structures to the mixing chamber further improves the mixing performance. We also developed a computer-controlled automated driver system to control the real-time fluid mixing and concentration regulation with the mixing module array. This research demonstrates the integration of digitally controllable polymer-based microfluidic modules as a fully functional system, which has great potential in the automation of many bio-fluid handling processes in bio-related applications.

  19. Droplet-based microfluidics and the dynamics of emulsions

    Science.gov (United States)

    Baret, Jean-Christophe; Brosseau, Quentin; Semin, Benoit; Qu, Xiaopeng

    2012-02-01

    Emulsions are complex fluids already involved for a long time in a wide-range of industrial processes, such as, for example, food, cosmetics or materials synthesis [1]. More recently, applications of emulsions have been extended to new fields like biotechnology or biochemistry where the compartmentalization of compounds in emulsion droplets is used to parallelise (bio-) chemical reactions [2]. Interestingly, these applications pinpoint to fundamental questions dealing with surfactant dynamics, dynamic surface tension, hydrodynamic interactions and electrohydrodynamics. Droplet-based microfluidics is a very powerful tool to quantitatively study the dynamics of emulsions at the single droplet level or even at the single interface level: well-controlled emulsions are produced and manipulated using hydrodynamics, electrical forces, optical actuation and combination of these effects. We will describe here how droplet-based microfluidics is used to extract quantitative informations on the physical-chemistry of emulsions for a better understanding and control of the dynamics of these systems [3].[4pt] [1] J. Bibette et al. Rep. Prog. Phys., 62, 969-1033 (1999)[0pt] [2] A. Theberge et al., Angewandte Chemie Int. Ed. 49, 5846 (2010)[0pt] [3] J.-C. Baret et al., Langmuir, 25, 6088 (2009)

  20. Microfluidic droplet-based liquid-liquid extraction.

    Science.gov (United States)

    Mary, Pascaline; Studer, Vincent; Tabeling, Patrick

    2008-04-15

    We study microfluidic systems in which mass exchanges take place between moving water droplets, formed on-chip, and an external phase (octanol). Here, no chemical reaction takes place, and the mass exchanges are driven by a contrast in chemical potential between the dispersed and continuous phases. We analyze the case where the microfluidic droplets, occupying the entire width of the channel, extract a solute-fluorescein-from the external phase (extraction) and the opposite case, where droplets reject a solute-rhodamine-into the external phase (purification). Four flow configurations are investigated, based on straight or zigzag microchannels. Additionally to the experimental work, we performed two-dimensional numerical simulations. In the experiments, we analyze the influence of different parameters on the process (channel dimensions, fluid viscosities, flow rates, drop size, droplet spacing, ...). Several regimes are singled out. In agreement with the mass transfer theory of Young et al. (Young, W.; Pumir, A.; Pomeau, Y. Phys. Fluids A 1989, 1, 462), we find that, after a short transient, the amount of matter transferred across the droplet interface grows as the square root of time and the time it takes for the transfer process to be completed decreases as Pe-2/3, where Pe is the Peclet number based on droplet velocity and radius. The numerical simulation is found in excellent consistency with the experiment. In practice, the transfer time ranges between a fraction and a few seconds, which is much faster than conventional systems. PMID:18351786

  1. TECHNICAL NOTE: Portable audio electronics for impedance-based measurements in microfluidics

    Science.gov (United States)

    Wood, Paul; Sinton, David

    2010-08-01

    We demonstrate the use of audio electronics-based signals to perform on-chip electrochemical measurements. Cell phones and portable music players are examples of consumer electronics that are easily operated and are ubiquitous worldwide. Audio output (play) and input (record) signals are voltage based and contain frequency and amplitude information. A cell phone, laptop soundcard and two compact audio players are compared with respect to frequency response; the laptop soundcard provides the most uniform frequency response, while the cell phone performance is found to be insufficient. The audio signals in the common portable music players and laptop soundcard operate in the range of 20 Hz to 20 kHz and are found to be applicable, as voltage input and output signals, to impedance-based electrochemical measurements in microfluidic systems. Validated impedance-based measurements of concentration (0.1-50 mM), flow rate (2-120 µL min-1) and particle detection (32 µm diameter) are demonstrated. The prevailing, lossless, wave audio file format is found to be suitable for data transmission to and from external sources, such as a centralized lab, and the cost of all hardware (in addition to audio devices) is ~10 USD. The utility demonstrated here, in combination with the ubiquitous nature of portable audio electronics, presents new opportunities for impedance-based measurements in portable microfluidic systems.

  2. Development of a microfluidic-based assay on a novel nitrocellulose platform.

    Science.gov (United States)

    Arrastia, Mary; Avoundjian, Ani; Ehrlich, Paul Said; Eropkin, Micah; Levine, Leanna; Gomez, Frank A

    2015-03-01

    A novel microfluidic paper-based analytical device (μPAD) utilizing a nitrocellulose (NC) membrane to detect IgG antibodies through a colorimetric analysis is described. The μPAD was constructed using layered polyethylene terephthalate (PET) and pressure-sensitive adhesives (PSA). The biotin labeled Goat Anti-Mouse IgG antibody was spotted and dried on the NC channel prior to subjecting it to a series of wash solutions (Tris-tween), increasing concentrations of alkaline phosphatase conjugated to streptavidin (Strep-ALP), and para-nitrophenyl phosphate (p-NPP) realizing a vibrant yellow color. The reaction proceeds for 10 min before applying the p-NPP stop solution. The device was then dried, scanned, and analyzed yielding a linear range of inverse yellow color intensities versus Strep-ALP concentrations. The development of this simple μPAD should further facilitate the use of NC in colorimetric assays to detect and quantitate antibodies. PMID:25545783

  3. Modeling and simulation of DNA flow in a microfluidic-based pathogen detection system

    Energy Technology Data Exchange (ETDEWEB)

    Trebotich, D; Miller, G H

    2005-01-31

    We present simulation results from a new computational model of DNA flow in microfluidic devices. This work is important because computational models are needed to design miniaturized biomedical devices that are becoming the state-of-the-art in many significant applications including pathogen detection as well as continuous monitoring and drug delivery. Currently advanced algorithms in design tools are non-existent but necessary to understand the complex fluid and polymer dynamics involved in biological flow at small scales. Our model is based on a fully coupled fluid-particle numerical algorithm with both stochastic and deterministic components in a bead-rod polymer representation. We have applied this work to DNA extraction configurations in a microfluidic PCR chamber used in a pathogen detection system. We demonstrate our method on the test problem of flow of a single DNA molecule in a 2D packed array microchannel. We are also investigating mechanisms for molecular ''sticking'' using short range forces.

  4. Enzyme-based microfluidic chip coupled to graphene electrodes for the detection of D-amino acid enantiomer-biomarkers.

    Science.gov (United States)

    Batalla, Pilar; Martín, Aída; López, Miguel Ángel; González, María Cristina; Escarpa, Alberto

    2015-01-01

    An electrochemical microfluidic strategy for the separation and enantiomeric detection of D-methionine (D-Met) and D-leucine (D-Leu) is presented. These D-amino acids (D-AAs) act as biomarkers involved in relevant diseases caused by Vibrio cholerae. On a single layout microfluidic chip (MC), highly compatible with extremely low biological sample consumption, the strategy allowed the controlled microfluidic D-AA separation and the specific reaction between D-amino acid oxidase (DAAO) and each D-AA biomarker avoiding the use of additives (i.e., cyclodextrins) for enantiomeric separation as well as any covalent immobilization of the enzyme into the wall channels or on the electrode surface such as in the biosensor-based approaches. Hybrid polymer/graphene-based electrodes were end-channel coupled to the microfluidic system to improve the analytical performance. D-Met and D-Leu were successfully detected becoming this proof-of-the-concept a promising principle for the development of point-of-care (POC) devices for in situ screening of V. cholerae related diseases. PMID:25870911

  5. Development of Multiscale Materials in Microfluidic Devices: Case Study for Viral Separation from Whole Blood

    Science.gov (United States)

    Surawathanawises, Krissada

    Separation and concentration of nanoscale species play an important role in various fields such as biotechnology, nanotechnology and environmental science. Inevitably, the separation efficiency strongly affects the quality of downstream detections or productions. Innovations in materials science that can separate bionanoparticles efficiently and do not require complex setups, reagents or external fields are highly demanded. This work focuses on developing new materials for the affinity separation of bio-nanoparticles such as viruses or macromolecules from a complex mixture, such as whole blood. To enhance the interaction between target nanoparticles and the capture bed, methods to produce porous matrices with a uniform pore size matching the dimension of targets are studied. Furthermore, regarding viral separation from whole blood, macroporous materials are further patterned into microarrays to allow multiscale separation. Considering the needs in resource-limited settings, these materials are integrated with microfluidic technologies to reduce the volume of samples and reagents, simplify operating processes, and enable the use of inexpensive and portable components. Beyond the application of viral separation as demonstrated in the work, the fundamental study of macroporous material formation and transport in these materials also shed light to the separation of many other nanospecies in multiscale materials. Specifically, two macroporous materials, based on template synthesis, are created in this work. The first type employs porous anodic aluminum oxide (AAO) films as the template to create hexagonal arrays of nanoposts. However, pore sizes and interpore distances (cell size) of ordered porous AAO films are limited by the conventional fabrication process. Moreover, the process usually yields defective pore morphologies and large pore and cell size distributions. To overcome these limitations, a patterning method using nanobead indentation on aluminum substrate

  6. 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.

  7. A droplet routing technique for fault-tolerant digital microfluidic devices

    NARCIS (Netherlands)

    Zhang, Xiao; Proosdij, van Frits; Kerkhoff, Hans G.

    2008-01-01

    Abstract—Efficient droplet routing is one of the key approaches for realizing fault-tolerant microfluidic biochips. It requires that run-time diagnosis and fault recovery can be made possible in such systems. This paper describes a droplet routing technique for a fault-tolerant digital microfluidic

  8. Drug testing and flow cytometry analysis on a large number of uniform sized tumor spheroids using a microfluidic device

    Science.gov (United States)

    Patra, Bishnubrata; Peng, Chien-Chung; Liao, Wei-Hao; Lee, Chau-Hwang; Tung, Yi-Chung

    2016-02-01

    Three-dimensional (3D) tumor spheroid possesses great potential as an in vitro model to improve predictive capacity for pre-clinical drug testing. In this paper, we combine advantages of flow cytometry and microfluidics to perform drug testing and analysis on a large number (5000) of uniform sized tumor spheroids. The spheroids are formed, cultured, and treated with drugs inside a microfluidic device. The spheroids can then be harvested from the device without tedious operation. Due to the ample cell numbers, the spheroids can be dissociated into single cells for flow cytometry analysis. Flow cytometry provides statistical information in single cell resolution that makes it feasible to better investigate drug functions on the cells in more in vivo-like 3D formation. In the experiments, human hepatocellular carcinoma cells (HepG2) are exploited to form tumor spheroids within the microfluidic device, and three anti-cancer drugs: Cisplatin, Resveratrol, and Tirapazamine (TPZ), and their combinations are tested on the tumor spheroids with two different sizes. The experimental results suggest the cell culture format (2D monolayer vs. 3D spheroid) and spheroid size play critical roles in drug responses, and also demonstrate the advantages of bridging the two techniques in pharmaceutical drug screening applications.

  9. High-performance microfluidic rectifier based on sudden expansion channel with embedded block structure.

    Science.gov (United States)

    Tsai, Chien-Hsiung; Lin, Che-Hsin; Fu, Lung-Ming; Chen, Hui-Chun

    2012-06-01

    A high-performance microfluidic rectifier incorporating a microchannel and a sudden expansion channel is proposed. In the proposed device, a block structure embedded within the expansion channel is used to induce two vortex structures at the end of the microchannel under reverse flow conditions. The vortices reduce the hydraulic diameter of the microchannel and, therefore, increase the flow resistance. The rectification performance of the proposed device is evaluated by both experimentally and numerically. The experimental and numerical values of the rectification performance index (i.e., the diodicity, Di) are found to be 1.54 and 1.76, respectively. Significantly, flow rectification is achieved without the need for moving parts. Thus, the proposed device is ideally suited to the high pressure environment characteristic of most micro-electro-mechanical-systems (MEMS)-based devices. Moreover, the rectification performance of the proposed device is superior to that of existing valveless rectifiers based on Tesla valves, simple nozzle/diffuser structures, or cascaded nozzle/diffuser structures.

  10. Microfluidic device for the formation of optically excitable, three-dimensional, compartmentalized motor units.

    Science.gov (United States)

    Uzel, Sebastien G M; Platt, Randall J; Subramanian, Vidya; Pearl, Taylor M; Rowlands, Christopher J; Chan, Vincent; Boyer, Laurie A; So, Peter T C; Kamm, Roger D

    2016-08-01

    Motor units are the fundamental elements responsible for muscle movement. They are formed by lower motor neurons and their muscle targets, synapsed via neuromuscular junctions (NMJs). The loss of NMJs in neurodegenerative disorders (such as amyotrophic lateral sclerosis or spinal muscle atrophy) or as a result of traumatic injuries affects millions of lives each year. Developing in vitro assays that closely recapitulate the physiology of neuromuscular tissues is crucial to understand the formation and maturation of NMJs, as well as to help unravel the mechanisms leading to their degeneration and repair. We present a microfluidic platform designed to coculture myoblast-derived muscle strips and motor neurons differentiated from mouse embryonic stem cells (ESCs) within a three-dimensional (3D) hydrogel. The device geometry mimics the spinal cord-limb physical separation by compartmentalizing the two cell types, which also facilitates the observation of 3D neurite outgrowth and remote muscle innervation. Moreover, the use of compliant pillars as anchors for muscle strips provides a quantitative functional readout of force generation. Finally, photosensitizing the ESC provides a pool of source cells that can be differentiated into optically excitable motor neurons, allowing for spatiodynamic, versatile, and noninvasive in vitro control of the motor units. PMID:27493991

  11. The influence of polydimethylsiloxane curing ratio on capillary pressure in microfluidic devices

    Energy Technology Data Exchange (ETDEWEB)

    Viola, Ilenia, E-mail: ilenia.viola@nano.cnr.it [National Nanotechnology Laboratory-Institute Nanoscience-CNR (NNL-CNR NANO), via Arnesano, I-73100 Lecce (Italy); National Nanotechnology Laboratory-Institute Nanoscience-CNR (NNL-CNR NANO), c/o Dipartimento di Fisica, Universita La Sapienza, I-00185 Roma (Italy); Zacheo, Antonella [National Nanotechnology Laboratory-Institute Nanoscience-CNR (NNL-CNR NANO), via Arnesano, I-73100 Lecce (Italy); Universita del Salento, Dip. Matematica e Fisica ' Ennio De Giorgi' , via Arnesano, I-73100 Lecce (Italy); Arima, Valentina [National Nanotechnology Laboratory-Institute Nanoscience-CNR (NNL-CNR NANO), via Arnesano, I-73100 Lecce (Italy); Arico, Antonino S. [CNR-ITAE Institute, via Salita S. Lucia sopra Contesse, I-98126 Messina (Italy); Cortese, Barbara [National Nanotechnology Laboratory-Institute Nanoscience-CNR (NNL-CNR NANO), via Arnesano, I-73100 Lecce (Italy); Manca, Michele [National Nanotechnology Laboratory-Institute Nanoscience-CNR (NNL-CNR NANO), via Arnesano, I-73100 Lecce (Italy); Italian Institute of Technology (IIT), Center for Biomolecular Nanotechnologies (Italy); Zocco, Anna [STMicroelectronics, MFD Division, Application Laboratory Lecce, via Arnesano, I-73100 Lecce (Italy); Taurino, Antonietta [CNR, Istituto per la Microelettronica e Microsistemi (IMM), via Monteroni, I-73100 Lecce (Italy); Rinaldi, Ross [National Nanotechnology Laboratory-Institute Nanoscience-CNR (NNL-CNR NANO), via Arnesano, I-73100 Lecce (Italy); Universita del Salento, Dip. Matematica e Fisica ' Ennio De Giorgi' , via Arnesano, I-73100 Lecce (Italy); and others

    2012-08-01

    Investigations on surface properties of poly(dimethylsiloxane) (PDMS) are justified by its large application ranges especially as coating polymer in fluidic devices. At a micrometer scale, the liquid dynamics is strongly modified by interactions with a solid surface. A crucial parameter for this process is microchannel wettability that can be tuned by acting on surface chemistry and topography. In literature, a number of multi-step, time and cost consuming chemical and physical procedures are reported. Here we selectively modify both wetting and mechanical properties by a single step treatment. Changes of PDMS surface were investigated by X-ray photoelectron spectroscopy and atomic force microscopy and the effects of interface properties on the liquid displacement inside a microfluidic system were evaluated. The negative capillary pressure obtained tailoring the PDMS wettability is believed to be promising to accurately control sample leakage inside integrated lab-on-chip by acting on the liquid confinement and thus to reduce the sample volume, liquid drying as well as cross-contamination during the operation.

  12. Microfluidic interface technology based on stereolithography for glass-based lab-on-a-chips.

    Science.gov (United States)

    Han, Song-I; Han, Ki-Ho

    2013-01-01

    As lab-on-a-chips are developed for on-chip integrated microfluidic systems with multiple functions, the development of microfluidic interface (MFI) technology to enable integration of complex microfluidic systems becomes increasingly important and faces many technical difficulties. Such difficulties include the need for more complex structures, the possibility of biological or chemical cross-contamination between functional compartments, and the possible need for individual compartments fabricated from different substrate materials. This chapter introduces MFI technology, based on rapid stereolithography, for a glass-based miniaturized genetic sample preparation system, as an example of a complex lab-on-a-chip that could include functional elements such as; solid-phase DNA extraction, polymerase chain reaction, and capillary electrophoresis. To enable the integration of a complex lab-on-a-chip system in a single chip, MFI technology based on stereolithography provides a simple method for realizing complex arrangements of one-step plug-in microfluidic interconnects, integrated microvalves for microfluidic control, and optical windows for on-chip optical processes.

  13. A microfluidic device for the continuous culture and analysis of Caenorhabditis elegans in a toxic aqueous environment

    International Nuclear Information System (INIS)

    The nematode Caenorhabditis elegans (C. elegans) receives attention as a bioindicator, and the C. elegans condition has been recently analyzed using microfluidic devices equipped with an imaging system. To establish a method without an imaging system, we have proposed a novel microfluidic device with which to analyze the condition of C. elegans from the capacitance change using a pair of micro-electrodes. The device was designed to culture C. elegans, to expose C. elegans to an external stimulus, such as a chemical or toxicant, and to measure the capacitance change which indicates the condition of C. elegans. In this study, to demonstrate the capability of our device in a toxic aqueous environment, the device was applied to examine the effect of cadmium on C. elegans. Thirty L4 larval stage C. elegans were divided into three groups. One group was a control group and the other groups were exposed to cadmium solutions with concentrations of 5% and 10% LC50 for 24 h. The capacitance change and the body volume of C. elegans as a reference were measured four times and we confirmed the correlation between them. It shows that our device can analyze the condition of C. elegans without an imaging system. (paper)

  14. A microfluidic device for the continuous culture and analysis of Caenorhabditis elegans in a toxic aqueous environment

    Science.gov (United States)

    Jung, Jaehoon; Nakajima, Masahiro; Tajima, Hirotaka; Huang, Qiang; Fukuda, Toshio

    2013-08-01

    The nematode Caenorhabditis elegans (C. elegans) receives attention as a bioindicator, and the C. elegans condition has been recently analyzed using microfluidic devices equipped with an imaging system. To establish a method without an imaging system, we have proposed a novel microfluidic device with which to analyze the condition of C. elegans from the capacitance change using a pair of micro-electrodes. The device was designed to culture C. elegans, to expose C. elegans to an external stimulus, such as a chemical or toxicant, and to measure the capacitance change which indicates the condition of C. elegans. In this study, to demonstrate the capability of our device in a toxic aqueous environment, the device was applied to examine the effect of cadmium on C. elegans. Thirty L4 larval stage C. elegans were divided into three groups. One group was a control group and the other groups were exposed to cadmium solutions with concentrations of 5% and 10% LC50 for 24 h. The capacitance change and the body volume of C. elegans as a reference were measured four times and we confirmed the correlation between them. It shows that our device can analyze the condition of C. elegans without an imaging system.

  15. 基于棉纤维的微流控通道装置的研制与应用%Development and application of the cotton fiber microfluidic channel device

    Institute of Scientific and Technical Information of China (English)

    王璐; 闫宏涛

    2014-01-01

    A thread-based microfluidic channel device was firstly designed and manufactured by our-selves .The device is composed of a support ,loading systems ,reservoir devices and a microfluidic terminal fixer .They can be assembled and moved freely ,and fit any microfluidic pattern and the wicking rate of the fluid can be controlled .This microfluidic channel device was applied to the separation of mixed dyes by sin-gle channel ,the determination of nitrite in soil and water by Y-shaped channel and the simultaneous deter-mination of copper and zinc in soil by triple-channel . The self-made microfluidic device is low-cost and portable .%研制了一种基于棉纤维的线段微流控分离/分析通道装置,包括支架、加样系统、储液装置以及微流控线端固定器,可自由灵活组合,以适应各种实验需要的微流控分离/分析通道,并可控制液体流速,满足多通道进样的微流控分离/分析体系。应用于单通道混合染料分离、“Y”型通道测定土壤样品和水样中亚硝酸根含量以及复合线三通道同时测定土壤样品中铜和锌的含量,结果令人满意。自制的微流控通道装置制作成本低、携带方便、实用性强。

  16. Microfluidic electrochemical reactors

    Science.gov (United States)

    Nuzzo, Ralph G.; Mitrovski, Svetlana M.

    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.

  17. Optimization of a microfluidic based electromagnetic energy harvester for shoe insoles

    Science.gov (United States)

    Rahman, M. M.; Atkin, R.; Kim, H.

    2015-12-01

    This paper reports improved performance of the 4th generation microfluidic based energy harvester by finding global optimization among various geometric parameters, resulting in the increase of power density by 6.89 times. Specifically, the power output was optimized by varying diameters and spans of a coil at different frequencies. To verify the optimization, a custom testing platform was constructed, which mimicked the periodic linear movement caused by a human foot. The final device produced total power of 455.77mW from a volume of 20×3.74×0.75cm3, resulting in a power density of 8.13mW/cm3 that was identified as one of the highest power densities among human-body-induced vibration based energy harvesters.

  18. A microfluidic device with multi-valves system to enable several simultaneous exposure tests on Caenorhabditis elegans

    Science.gov (United States)

    Jung, Jaehoon; Nakajima, Masahiro; Masaru, Takeuchi; Huang, Qiang; Fukuda, Toshio

    2014-03-01

    In this paper, we report on a microfluidic device with a multi-valve system to conduct several exposure tests on Caenorhabditis elegans (C. elegans) simultaneously. It has pneumatic valves and no-moving-parts (NMP) valves. An NMP valve is incorporated with a chamber and enables the unidirectional movement of C. elegans in the chamber; once worms are loaded into the chamber, they cannot exit, regardless of the flow direction. To demonstrate the ability of the NMP valve to handle worms, we made a microfluidic device with three chambers. Each chamber was used to expose worms to Cd and Cu solutions, and K-medium. A pair of electrodes was installed in the device and the capacitance in-between the electrode was measured. When a C. elegans passed through the electrodes, the capacitance was changed. The capacitance change was proportional to the body volume of the worm, thus the body volume change by the heavy metal exposure was measured in the device. Thirty worms were divided into three groups and exposed to each solution. We confirmed that the different solutions induced differences in the capacitance changes for each group. These results indicate that our device is a viable method for simultaneously analyzing the effect of multiple stimuli on C. elegans.

  19. 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.

  20. Zeta potential and electroosmotic mobility in microfluidic devices fabricated from hydrophobic polymers: 1. The origins of charge.

    Science.gov (United States)

    Tandon, Vishal; Bhagavatula, Sharath K; Nelson, Wyatt C; Kirby, Brian J

    2008-03-01

    This paper combines new experimental data for electrokinetic characterization of hydrophobic polymers with a detailed discussion of the putative origins of charge at water-hydrophobe interfaces. Complexities in determining the origin of charge are discussed in the context of design and modeling challenges for electrokinetic actuation in hydrophobic microfluidic devices with aqueous working fluids. Measurements of interfacial charge are complicated by slip and interfacial water structuring phenomena (see Part 2, this issue). Despite these complexities, it is shown that (i) several hydrophobic materials, such as Teflon and Zeonor, have predictable electrokinetic properties and (ii) electrokinetic data for hydrophobic microfluidic systems is most consistent with the postulate that hydroxyl ion adsorption is the origin of charge.

  1. Microfluidic assessment of swimming media for motility-based sperm selection.

    Science.gov (United States)

    Eamer, Lise; Nosrati, Reza; Vollmer, Marion; Zini, Armand; Sinton, David

    2015-07-01

    Selection medium is important in sperm isolation for assisted reproductive technologies. Contrary to the naturally occurring human cervical mucus which has a high viscosity, most current practices for motility based sperm selection use a low viscosity medium. In this study, we used a microfluidic device to assess the effects of high viscosity media made with hyaluronic acid (HA) and methyl cellulose (MC) on bovine and human sperm motility and viability (sperm transferred directly from cryoprotectant). The microfluidic penetration test, viability, and motility were compared for sperm swimming in both HA and MC media with about 20cp viscosity (measured at 20 °C). Our resulted indicate that MC medium resulted in a significantly higher number of viable bovine sperm penetrating the medium as compared to HA. Furthermore, MC resulted in the selection of a sperm subpopulation with a 274% increase in sperm viability in comparison to the raw semen, while HA increased viability by only 133%. In addition to viability, bovine sperm motility parameters were significantly higher in the MC medium as compared with HA. Experiments with human sperm swimming in MC indicate that sperm swim slower and straighter at higher viscosities. In conclusion, the results indicate that in a micro-confined environment representative of the in vivo environment, MC is a preferred high viscosity medium to ensure the highest concentration of motile and viable sperm. PMID:26339314

  2. Single Cell Analysis of Yeast Replicative Aging Using a New Generation of Microfluidic Device

    OpenAIRE

    Yi Zhang; Chunxiong Luo; Ke Zou; Zhengwei Xie; Onn Brandman; Qi Ouyang; Hao Li

    2012-01-01

    A major limitation to yeast aging study has been the inability to track mother cells and observe molecular markers during the aging process. The traditional lifespan assay relies on manual micro-manipulation to remove daughter cells from the mother, which is laborious, time consuming, and does not allow long term tracking with high resolution microscopy. Recently, we have developed a microfluidic system capable of retaining mother cells in the microfluidic chambers while removing daughter cel...

  3. Fabrication of continuous flow microfluidics device with 3D electrode structures for high throughput DEP applications using mechanical machining.

    Science.gov (United States)

    Zeinali, Soheila; Çetin, Barbaros; Oliaei, Samad Nadimi Bavil; Karpat, Yiğit

    2015-07-01

    Microfluidics is the combination of micro/nano fabrication techniques with fluid flow at microscale to pursue powerful techniques in controlling and manipulating chemical and biological processes. Sorting and separation of bio-particles are highly considered in diagnostics and biological analyses. Dielectrophoresis (DEP) has offered unique advantages for microfluidic devices. In DEP devices, asymmetric pair of planar electrodes could be employed to generate non-uniform electric fields. In DEP applications, facing 3D sidewall electrodes is considered to be one of the key solutions to increase device throughput due to the generated homogeneous electric fields along the height of microchannels. Despite the advantages, fabrication of 3D vertical electrodes requires a considerable challenge. In this study, two alternative fabrication techniques have been proposed for the fabrication of a microfluidic device with 3D sidewall electrodes. In the first method, both the mold and the electrodes are fabricated using high precision machining. In the second method, the mold with tilted sidewalls is fabricated using high precision machining and the electrodes are deposited on the sidewall using sputtering together with a shadow mask fabricated by electric discharge machining. Both fabrication processes are assessed as highly repeatable and robust. Moreover, the two methods are found to be complementary with respect to the channel height. Only the manipulation of particles with negative-DEP is demonstrated in the experiments, and the throughput values up to 105 particles / min is reached in a continuous flow. The experimental results are compared with the simulation results and the limitations on the fabrication techniques are also discussed.

  4. 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.

  5. Dry adhesive bonding of nanoporous inorganic membranes to microfluidic devices using the OSTE(+) dual-cure polymer

    International Nuclear Information System (INIS)

    We present two transfer bonding schemes for incorporating fragile nanoporous inorganic membranes into microdevices. Such membranes are finding increasing use in microfluidics, due to their precisely controllable nanostructure. Both schemes rely on a novel dual-cure dry adhesive bonding method, enabled by a new polymer formulation: OSTE(+), which can form bonds at room temperature. OSTE(+) is a novel dual-cure ternary monomer system containing epoxy. After the first cure, the OSTE(+) is soft and suitable for bonding, while during the second cure it stiffens and obtains a Young’s modulus of 1.2 GPa. The ability of the epoxy to react with almost any dry surface provides a very versatile fabrication method. We demonstrate the transfer bonding of porous silicon and porous alumina membranes to polymeric microfluidic chips molded into OSTE(+), and of porous alumina membranes to microstructured silicon wafers, by using the OSTE(+) as a thin bonding layer. We discuss the OSTE(+) dual-cure mechanism, describe the device fabrication and evaluate the bond strength and membrane flow properties after bonding. The membranes bonded to OSTE(+) chips delaminate at 520 kPa, and the membranes bonded to silicon delaminate at 750 kPa, well above typical maximum pressures applied to microfluidic circuits. Furthermore, no change in the membrane flow resistance was observed after bonding. (paper)

  6. Dry adhesive bonding of nanoporous inorganic membranes to microfluidic devices using the OSTE(+) dual-cure polymer

    Science.gov (United States)

    Saharil, Farizah; Forsberg, Fredrik; Liu, Yitong; Bettotti, Paolo; Kumar, Neeraj; Niklaus, Frank; Haraldsson, Tommy; van der Wijngaart, Wouter; Gylfason, Kristinn B.

    2013-02-01

    We present two transfer bonding schemes for incorporating fragile nanoporous inorganic membranes into microdevices. Such membranes are finding increasing use in microfluidics, due to their precisely controllable nanostructure. Both schemes rely on a novel dual-cure dry adhesive bonding method, enabled by a new polymer formulation: OSTE(+), which can form bonds at room temperature. OSTE(+) is a novel dual-cure ternary monomer system containing epoxy. After the first cure, the OSTE(+) is soft and suitable for bonding, while during the second cure it stiffens and obtains a Young’s modulus of 1.2 GPa. The ability of the epoxy to react with almost any dry surface provides a very versatile fabrication method. We demonstrate the transfer bonding of porous silicon and porous alumina membranes to polymeric microfluidic chips molded into OSTE(+), and of porous alumina membranes to microstructured silicon wafers, by using the OSTE(+) as a thin bonding layer. We discuss the OSTE(+) dual-cure mechanism, describe the device fabrication and evaluate the bond strength and membrane flow properties after bonding. The membranes bonded to OSTE(+) chips delaminate at 520 kPa, and the membranes bonded to silicon delaminate at 750 kPa, well above typical maximum pressures applied to microfluidic circuits. Furthermore, no change in the membrane flow resistance was observed after bonding.

  7. Development of low-cost sensing and separation devices based on macro, micro and nano technology for health applications

    OpenAIRE

    Crowley, Una Bernadette

    2014-01-01

    The work presented in this thesis described the development of low-cost sensing and separation devices with electrochemical detections for health applications. This research employs macro, micro and nano technology. The first sensing device developed was a tonerbased micro-device. The initial development of microfluidic devices was based on glass or quartz devices that are often expensive to fabricate; however, the introduction of new types of materials, such as plastics, offered a new way fo...

  8. A microfluidic cell-trapping device for single-cell tracking of host-microbe interactions.

    Science.gov (United States)

    Delincé, Matthieu J; Bureau, Jean-Baptiste; López-Jiménez, Ana Teresa; Cosson, Pierre; Soldati, Thierry; McKinney, John D

    2016-08-16

    The impact of cellular individuality on host-microbe interactions is increasingly appreciated but studying the temporal dynamics of single-cell behavior in this context remains technically challenging. Here we present a microfluidic platform, InfectChip, to trap motile infected cells for high-resolution time-lapse microscopy. This approach allows the direct visualization of all stages of infection, from bacterial uptake to death of the bacterium or host cell, over extended periods of time. We demonstrate the utility of this approach by co-culturing an established host-cell model, Dictyostelium discoideum, with the extracellular pathogen Klebsiella pneumoniae or the intracellular pathogen Mycobacterium marinum. We show that the outcome of such infections is surprisingly heterogeneous, ranging from abortive infection to death of the bacterium or host cell. InfectChip thus provides a simple method to dissect the time-course of host-microbe interactions at the single-cell level, yielding new insights that could not be gleaned from conventional population-based measurements. PMID:27425421

  9. Asphaltene based photovoltaic devices

    Science.gov (United States)

    Chianelli, Russell R.; Castillo, Karina; Gupta, Vipin; Qudah, Ali M.; Torres, Brenda; Abujnah, Rajib E.

    2016-03-22

    Photovoltaic devices and methods of making the same, are disclosed herein. The cell comprises a photovoltaic device that comprises a first electrically conductive layer comprising a photo-sensitized electrode; at least one photoelectrochemical layer comprising metal-oxide particles, an electrolyte solution comprising at least one asphaltene fraction, wherein the metal-oxide particles are optionally dispersed in a surfactant; and a second electrically conductive layer comprising a counter-electrode, wherein the second electrically conductive layer comprises one or more conductive elements comprising carbon, graphite, soot, carbon allotropes or any combinations thereof.

  10. 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. PMID:27054814

  11. 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.

  12. Performance study of acoustophoretic microfluidic silicon-glass devices by characterization of material- and geometry-dependent frequency spectra

    CERN Document Server

    Garofalo, Fabio; Bruus, Henrik

    2016-01-01

    The mechanical and electrical response of acoustophoretic microfluidic devices attached to an ac-voltage-driven piezoelectric transducer is studied by means of numerical simulations. The governing equations are formulated in a variational framework that, introducing Lagrangian and Hamiltonian densities, is used to derive the weak form for the finite element discretization of the equations and to characterize the device response in terms of frequency-dependent figures of merit or indicators. The effectiveness of the device in focusing microparticles is quantified by two mechanical indicators: the average direction of the pressure gradient and the amount of acoustic energy localized in the microchannel. Further, we derive the relations between the Lagrangian, the Hamiltonian and three electrical indicators: the resonance Q-value, the impedance and the electric power. The frequency response of the hard-to-measure mechanical indicators is correlated to that of the easy-to-measure electrical indicators, and by int...

  13. Microfluidic devices, systems, and methods for quantifying particles using centrifugal force

    Science.gov (United States)

    Schaff, Ulrich Y.; Sommer, Gregory J.; Singh, Anup K.

    2015-11-17

    Embodiments of the present invention are directed toward microfluidic systems, apparatus, and methods for measuring a quantity of cells in a fluid. Examples include a differential white blood cell measurement using a centrifugal microfluidic system. A method may include introducing a fluid sample containing a quantity of cells into a microfluidic channel defined in part by a substrate. The quantity of cells may be transported toward a detection region defined in part by the substrate, wherein the detection region contains a density media, and wherein the density media has a density lower than a density of the cells and higher than a density of the fluid sample. The substrate may be spun such that at least a portion of the quantity of cells are transported through the density media. Signals may be detected from label moieties affixed to the cells.

  14. Microfluidic-Based Multi-Organ Platforms for Drug Discovery

    Directory of Open Access Journals (Sweden)

    Ahmad Rezaei Kolahchi

    2016-09-01

    Full Text Available Development of predictive multi-organ models before implementing costly clinical trials is central for screening the toxicity, efficacy, and side effects of new therapeutic agents. Despite significant efforts that have been recently made to develop biomimetic in vitro tissue models, the clinical application of such platforms is still far from reality. Recent advances in physiologically-based pharmacokinetic and pharmacodynamic (PBPK-PD modeling, micro- and nanotechnology, and in silico modeling have enabled single- and multi-organ platforms for investigation of new chemical agents and tissue-tissue interactions. This review provides an overview of the principles of designing microfluidic-based organ-on-chip models for drug testing and highlights current state-of-the-art in developing predictive multi-organ models for studying the cross-talk of interconnected organs. We further discuss the challenges associated with establishing a predictive body-on-chip (BOC model such as the scaling, cell types, the common medium, and principles of the study design for characterizing the interaction of drugs with multiple targets.

  15. High-throughput injection with microfluidics using picoinjectors

    OpenAIRE

    Abate, Adam R.; Hung, Tony; Mary, Pascaline; Agresti, Jeremy J.; Weitz, David A.

    2010-01-01

    Adding reagents to drops is one of the most important functions in droplet-based microfluidic systems; however, a robust technique to accomplish this does not exist. Here, we introduce the picoinjector, a robust device to add controlled volumes of reagent using electro-microfluidics at kilohertz rates. It can also perform multiple injections for serial and combinatorial additions.

  16. Bead-Based Microfluidic Sediment Analogues: Fabrication and Colloid Transport.

    Science.gov (United States)

    Guo, Yang; Huang, Jingwei; Xiao, Feng; Yin, Xiaolong; Chun, Jaehun; Um, Wooyong; Neeves, Keith B; Wu, Ning

    2016-09-13

    Mobile colloids can act as carriers for low-solubility contaminants in the environment. However, the dominant mechanism for this colloid-facilitated transport of chemicals is unclear. Therefore, we developed a bead-based microfluidic platform of sediment analogues and measured both single and population transport of model colloids. The porous medium is assembled through a bead-by-bead injection method. This approach has the versatility to build both electrostatically homogeneous and heterogeneous media at the pore scale. A T-junction at the exit also allowed for encapsulation and enumeration of colloids effluent at single particle resolution to give population dynamics. Tortuosity calculated from pore-scale trajectory analysis and its comparison with lattice Boltzmann simulations revealed that transport of colloids was influenced by the size exclusion effect. The porous media packed by positively and negatively charged beads into two layers showed distinctive colloidal particle retention and significant remobilization and re-adsorption of particles during water flushing. We demonstrated the potential of our method to fabricate porous media with surface heterogeneities at the pore scale. With both single and population dynamics measurement, our platform has the potential to connect pore-scale and macroscale colloid transport on a lab scale and to quantify the impact of grain surface heterogeneities that are natural in the subsurface environment. PMID:27548505

  17. Structural studies of enzyme-based microfluidic biofuel cells

    Science.gov (United States)

    Togo, Makoto; Takamura, Akimasa; Asai, Tatsuya; Kaji, Hirokazu; Nishizawa, Matsuhiko

    An enzyme-based glucose/O 2 biofuel cell was constructed within a microfluidic channel to study the influence of electrode configuration and fluidic channel height on cell performance. The cell was composed of a bilirubin oxidase (BOD)-adsorbed O 2 cathode and a glucose anode prepared by co-immobilization of glucose dehydrogenase (GDH), diaphorase (Dp) and VK 3-pendant poly- L-lysine. The consumption of O 2 at the upstream cathode protected the downstream anode from interfering O 2 molecules, and consequently improved the cell performance (maximum cell current) ca. 10% for the present cell. The cell performance was also affected by the channel height. The output current and power of a 0.1 mm-height cell was significantly less than those of a 1 mm-height cell because of the depletion of O 2, as determined by the shape of the E- I curve at the cathode. On the other hand, the volume density of current and power was several times higher for the narrower cell.

  18. Structural studies of enzyme-based microfluidic biofuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Togo, Makoto; Takamura, Akimasa; Asai, Tatsuya; Kaji, Hirokazu; Nishizawa, Matsuhiko [Department of Bioengineering and Robotics, Graduate School of Engineering, Tohoku University, Aoba 6-6-01, Aramaki, Aoba-ku, Sendai, Miyagi 980-8579 (Japan)

    2008-03-15

    An enzyme-based glucose/O{sub 2} biofuel cell was constructed within a microfluidic channel to study the influence of electrode configuration and fluidic channel height on cell performance. The cell was composed of a bilirubin oxidase (BOD)-adsorbed O{sub 2} cathode and a glucose anode prepared by co-immobilization of glucose dehydrogenase (GDH), diaphorase (Dp) and VK{sub 3}-pendant poly-L-lysine. The consumption of O{sub 2} at the upstream cathode protected the downstream anode from interfering O{sub 2} molecules, and consequently improved the cell performance (maximum cell current) ca. 10% for the present cell. The cell performance was also affected by the channel height. The output current and power of a 0.1 mm-height cell was significantly less than those of a 1 mm-height cell because of the depletion of O{sub 2}, as determined by the shape of the E-I curve at the cathode. On the other hand, the volume density of current and power was several times higher for the narrower cell. (author)

  19. An integrated microfluidic biochemical detection system for protein analysis with magnetic bead-based sampling capabilities.

    Science.gov (United States)

    Choi, Jin-Woo; Oh, Kwang W; Thomas, Jennifer H; Heineman, William R; Halsall, H Brian; Nevin, Joseph H; Helmicki, Arthur J; Henderson, H Thurman; Ahn, Chong H

    2002-02-01

    This paper presents the development and characterization of an integrated microfluidic biochemical detection system for fast and low-volume immunoassays using magnetic beads, which are used as both immobilization surfaces and bio-molecule carriers. Microfluidic components have been developed and integrated to construct a microfluidic biochemical detection system. Magnetic bead-based immunoassay, as a typical example of biochemical detection and analysis, has been successfully performed on the integrated microfluidic biochemical analysis system that includes a surface-mounted biofilter and electrochemical sensor on a glass microfluidic motherboard. Total time required for an immunoassay was less than 20 min including sample incubation time, and sample volume wasted was less than 50 microl during five repeated assays. Fast and low-volume biochemical analysis has been successfully achieved with the developed biofilter and immunosensor, which is integrated to the microfluidic system. Such a magnetic bead-based biochemical detection system, described in this paper, can be applied to protein analysis systems. PMID:15100857

  20. A low-cost, manufacturable method for fabricating capillary and optical fiber interconnects for microfluidic devices.

    Science.gov (United States)

    Hartmann, Daniel M; Nevill, J Tanner; Pettigrew, Kenneth I; Votaw, Gregory; Kung, Pang-Jen; Crenshaw, Hugh C

    2008-04-01

    Microfluidic chips require connections to larger macroscopic components, such as light sources, light detectors, and reagent reservoirs. In this article, we present novel methods for integrating capillaries, optical fibers, and wires with the channels of microfluidic chips. The method consists of forming planar interconnect channels in microfluidic chips and inserting capillaries, optical fibers, or wires into these channels. UV light is manually directed onto the ends of the interconnects using a microscope. UV-curable glue is then allowed to wick to the end of the capillaries, fibers, or wires, where it is cured to form rigid, liquid-tight connections. In a variant of this technique, used with light-guiding capillaries and optical fibers, the UV light is directed into the capillaries or fibers, and the UV-glue is cured by the cone of light emerging from the end of each capillary or fiber. This technique is fully self-aligned, greatly improves both the quality and the manufacturability of the interconnects, and has the potential to enable the fabrication of interconnects in a fully automated fashion. Using these methods, including a semi-automated implementation of the second technique, over 10,000 interconnects have been formed in almost 2000 microfluidic chips made of a variety of rigid materials. The resulting interconnects withstand pressures up to at least 800psi, have unswept volumes estimated to be less than 10 femtoliters, and have dead volumes defined only by the length of the capillary. PMID:18369517

  1. Microfluidic assembly kit based on laser-cut building blocks for education and fast prototyping.

    Science.gov (United States)

    Gerber, Lukas C; Kim, Honesty; Riedel-Kruse, Ingmar H

    2015-11-01

    Here, we present an inexpensive rapid-prototyping method that allows researchers and children to quickly assemble multi-layered microfluidic devices from easily pre-fabricated building blocks. We developed low-cost (building block pieces and double-sided tape that allow users to generate water droplets in oil, capture living cells, and conduct basic phototaxis experiments. We developed and tested a 90-min lesson plan with children aged 12-14 yr and provide here the instructions for teachers to replicate these experiments and lessons. All parts of the kit are easy to make or order. We propose to use such easy to fabricate kits in labs with no access to current microfluidic tools as well as in classroom environments to get exposure to the powerful techniques of microfluidics. PMID:26634013

  2. Carbon based prosthetic devices

    Energy Technology Data Exchange (ETDEWEB)

    Devlin, D.J.; Carroll, D.W.; Barbero, R.S.; Archuleta, T. [Los Alamos National Lab., NM (US); Klawitter, J.J.; Ogilvie, W.; Strzepa, P. [Ascension Orthopedics (US); Cook, S.D. [Tulane Univ., New Orleans, LA (US). School of Medicine

    1998-12-31

    This is the final report of a one-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The project objective was to evaluate the use of carbon/carbon-fiber-reinforced composites for use in endoprosthetic devices. The application of these materials for the metacarpophalangeal (MP) joints of the hand was investigated. Issues concerning mechanical properties, bone fixation, biocompatibility, and wear are discussed. A system consisting of fiber reinforced materials with a pyrolytic carbon matrix and diamond-like, carbon-coated wear surfaces was developed. Processes were developed for the chemical vapor infiltration (CVI) of pyrolytic carbon into porous fiber preforms with the ability to tailor the outer porosity of the device to provide a surface for bone in-growth. A method for coating diamond-like carbon (DLC) on the articulating surface by plasma-assisted chemical vapor deposition (CVD) was developed. Preliminary results on mechanical properties of the composite system are discussed and initial biocompatibility studies were performed.

  3. 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. PMID:26322591

  4. An Incompressible, Depth-Averaged Lattice Boltzmann Method for Liquid Flow in Microfluidic Devices with Variable Aperture

    Directory of Open Access Journals (Sweden)

    Artin Laleian

    2015-11-01

    Full Text Available Two-dimensional (2D pore-scale models have successfully simulated microfluidic experiments of aqueous-phase flow with mixing-controlled reactions in devices with small aperture. A standard 2D model is not generally appropriate when the presence of mineral precipitate or biomass creates complex and irregular three-dimensional (3D pore geometries. We modify the 2D lattice Boltzmann method (LBM to incorporate viscous drag from the top and bottom microfluidic device (micromodel surfaces, typically excluded in a 2D model. Viscous drag from these surfaces can be approximated by uniformly scaling a steady-state 2D velocity field at low Reynolds number. We demonstrate increased accuracy by approximating the viscous drag with an analytically-derived body force which assumes a local parabolic velocity profile across the micromodel depth. Accuracy of the generated 2D velocity field and simulation permeability have not been evaluated in geometries with variable aperture. We obtain permeabilities within approximately 10% error and accurate streamlines from the proposed 2D method relative to results obtained from 3D simulations. In addition, the proposed method requires a CPU run time approximately 40 times less than a standard 3D method, representing a significant computational benefit for permeability calculations.

  5. From bioseparation to artificial micro-organs: microfluidic chip based particle manipulation techniques

    Science.gov (United States)

    Stelzle, Martin

    2010-02-01

    Microfluidic device technology provides unique physical phenomena which are not available in the macroscopic world. These may be exploited towards a diverse array of applications in biotechnology and biomedicine ranging from bioseparation of particulate samples to the assembly of cells into structures that resemble the smallest functional unit of an organ. In this paper a general overview of chip-based particle manipulation and separation is given. In the state of the art electric, magnetic, optical and gravitational field effects are utilized. Also, mechanical obstacles often in combination with force fields and laminar flow are employed to achieve separation of particles or molecules. In addition, three applications based on dielectrophoretic forces for particle manipulation in microfluidic systems are discussed in more detail. Firstly, a virus assay is demonstrated. There, antibody-loaded microbeads are used to bind virus particles from a sample and subsequently are accumulated to form a pico-liter sized aggregate located at a predefined position in the chip thus enabling highly sensitive fluorescence detection. Secondly, subcellular fractionation of mitochondria from cell homogenate yields pure samples as was demonstrated by Western Blot and 2D PAGE analysis. Robust long-term operation with complex cell homogenate samples while avoiding electrode fouling is achieved by a set of dedicated technical means. Finally, a chip intended for the dielectrophoretic assembly of hepatocytes and endothelial cells into a structure resembling a liver sinusoid is presented. Such "artificial micro organs" are envisioned as substance screening test systems providing significantly higher predictability with respect to the in vivo response towards a substance under test.

  6. Routing-based Synthesis of Digital Microfluidic Biochips

    DEFF Research Database (Denmark)

    Maftei, Elena; Pop, Paul; Madsen, Jan

    2010-01-01

    Microfluidic biochips are replacing the conventional biochemical analyzers, and are able to integrate on-chip all the basic functsions for biochemical analysis. The "digital" microfluidic biochips are manipulating liquids not as a continuous flow, but as discrete droplets on a two-dimensional array...... the concept of virtual modules and allow the droplets to move on the chip on any route during operation execution. Thus, the synthesis problem is transformed into a routing problem. We propose an approach derived from a Greedy Randomized Adaptive Search Procedure (GRASP) and we show that by considering...

  7. Simplified prototyping of perfusable polystyrene microfluidics

    Science.gov (United States)

    Tran, Reginald; Ahn, Byungwook; R. Myers, David; Qiu, Yongzhi; Sakurai, Yumiko; Moot, Robert; Mihevc, Emma; Trent Spencer, H.; Doering, Christopher; A. Lam, Wilbur

    2014-01-01

    Cell culture in microfluidic systems has primarily been conducted in devices comprised of polydimethylsiloxane (PDMS) or other elastomers. As polystyrene (PS) is the most characterized and commonly used substrate material for cell culture, microfluidic cell culture would ideally be conducted in PS-based microsystems that also enable tight control of perfusion and hydrodynamic conditions, which are especially important for culture of vascular cell types. Here, we report a simple method to prototype perfusable PS microfluidics for endothelial cell culture under flow that can be fabricated using standard lithography and wet laboratory equipment to enable stable perfusion at shear stresses up to 300 dyn/cm2 and pumping pressures up to 26 kPa for at least 100 h. This technique can also be extended to fabricate perfusable hybrid PS-PDMS microfluidics of which one application is for increased efficiency of viral transduction in non-adherent suspension cells by leveraging the high surface area to volume ratio of microfluidics and adhesion molecules that are optimized for PS substrates. These biologically compatible microfluidic devices can be made more accessible to biological-based laboratories through the outsourcing of lithography to various available microfluidic foundries. PMID:25379106

  8. Uniform yeast cell assembly via microfluidics

    OpenAIRE

    Chang, Ya-Wen; He, Peng; Marquez, Samantha M.; Cheng, Zhengdong

    2012-01-01

    This paper reports the use of microfluidic approaches for the fabrication of yeastosomes (yeast-celloidosomes) based on self-assembly of yeast cells onto liquid-solid or liquid-gas interfaces. Precise control over fluidic flows in droplet- and bubble-forming microfluidic devices allows production of monodispersed, size-selected templates. The general strategy to organize and assemble living cells is to tune electrostatic attractions between the template (gel or gas core) and the cells via sur...

  9. 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.

  10. Monitoring of TGF-β 1-Induced Human Lung Adenocarcinoma A549 Cells Epithelial-Mesenchymal Transformation Process by Measuring Cell Adhesion Force with a Microfluidic Device.

    Science.gov (United States)

    Li, Yuan; Gao, AnXiu; Yu, Ling

    2016-01-01

    The epithelial-mesenchymal transition (EMT) is a process in which epithelial cells lose their cell polarity and cell-cell adhesion, and gain migratory and invasive properties. It is believed that EMT is associated with initiation and completion of the invasion-metastasis cascade. In this study, an economic approach was developed to fabricate a microfluidic device with less instrumentation requirement for the investigation of EMT by quantifying cell adhesion force. Fluid shear force was precisely controlled by a homemade microfluidic perfusion apparatus and interface. The adhesion capability of the human lung adenocarcinoma cell line A549 on different types of extracellular matrix protein was studied. In addition, effects of transforming growth factor-β (TGF-β) on EMT in A549 cells were investigated by characterizing the adhesion force changes and on-chip fluorescent staining. The results demonstrate that the microfluidic device is a potential tool to characterize the epithelial-mesenchymal transition process by measuring cell adhesion force.

  11. 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.

  12. Rapid fabrication of a four-layer PMMA-based microfluidic chip using CO2-laser micromachining and thermal bonding

    Science.gov (United States)

    Chen, Xueye; Shen, Jienan; Zhou, Mengde

    2016-10-01

    A smart design method to transform the original two-layer microfluidic chip into a four-layer 3D microfluidic chip is proposed. A novel fabrication method is established to rapidly and effectively produce a four-layer microfluidic chip device made entirely from polymethylmethacrylate (PMMA). Firstly, the CO2-laser cuts the PMMA sheets by melting and blowing away vaporized material from the parent material to obtain high-quality channels of the microfluidic chip. An orthogonal experimental method is used to study its processing stability. In addition, a simple, rapid thermal bonding technique is successfully applied in fabricating the four-layer microfluidic chip, which has a bond strength of 1.3 MPa. A wooden pole is used to improve the accuracy of the alignment. Finally, a mixing experiment with blue ink and water is carried out, which proves that this smart design method and rapid manufacturing technology are successful.

  13. Digital microfluidic operations on micro-electrode dot array architecture.

    Science.gov (United States)

    Wang, G; Teng, D; Fan, S-K

    2011-12-01

    As digital microfluidics-based biochips find more applications, their complexity is expected to increase significantly owing to the trend of multiple and concurrent assays on the chip. There is a pressing need to deliver a top-down design methodology that the biochip designer can leverage the same level of computer-aided design support as the semi-conductor industry now does. Moreover, as microelectronics fabrication technology is scaling up and integrated device performance is improving, it is expected that these microfluidic biochips will be integrated with microelectronic components in next-generation system-on-chip designs. This study presents the analysis and experiments of digital microfluidic operations on a novel electrowetting-on-dielectric-based 'micro-electrode dot array architecture' that fosters a development path for hierarchical top-down design approach for digital microfluidics. The proposed architecture allows dynamic configurations and activations of identical basic microfluidic unit called 'micro-electrode cells' to design microfluidic components, layouts, routing, microfluidic operations and applications of the biochip hierarchically. Fundamental microfluidic operations have been successfully performed by the architecture. In addition, this novel architecture demonstrates a number of advantages and flexibilities over the conventional digital microfluidics in performing advanced microfluidic operations. PMID:22149873

  14. Microchip-based electrochemical detection using a 3-D printed wall-jet electrode device.

    Science.gov (United States)

    Munshi, Akash S; Martin, R Scott

    2016-02-01

    Three dimensional (3-D) printing technology has evolved dramatically in the last few years, offering the capability of printing objects with a variety of materials. Printing microfluidic devices using this technology offers various advantages such as ease and uniformity of fabrication, file sharing between laboratories, and increased device-to-device reproducibility. One unique aspect of this technology, when used with electrochemical detection, is the ability to produce a microfluidic device as one unit while also allowing the reuse of the device and electrode for multiple analyses. Here we present an alternate electrode configuration for microfluidic devices, a wall-jet electrode (WJE) approach, created by 3-D printing. Using microchip-based flow injection analysis, we compared the WJE design with the conventionally used thin-layer electrode (TLE) design. It was found that the optimized WJE system enhances analytical performance (as compared to the TLE design), with improvements in sensitivity and the limit of detection. Experiments were conducted using two working electrodes - 500 μm platinum and 1 mm glassy carbon. Using the 500 μm platinum electrode the calibration sensitivity was 16 times higher for the WJE device (as compared to the TLE design). In addition, use of the 1 mm glassy carbon electrode led to limit of detection of 500 nM for catechol, as compared to 6 μM for the TLE device. Finally, to demonstrate the versatility and applicability of the 3-D printed WJE approach, the device was used as an inexpensive electrochemical detector for HPLC. The number of theoretical plates was comparable to the use of commercially available UV and MS detectors, with the WJE device being inexpensive to utilize. These results show that 3-D-printing can be a powerful tool to fabricate reusable and integrated microfluidic detectors in configurations that are not easily achieved with more traditional lithographic methods. PMID:26649363

  15. Single cell studies of mouse embryonic stem cell (mESC) differentiation by electrical impedance measurements in a microfluidic device

    Science.gov (United States)

    Zhou, Ying; Basu, Srinjan; Laue, Ernest; Seshia, Ashwin A.

    2016-01-01

    Biological populations of cells show considerable cell-to-cell variability. Study of single cells and analysis of cell heterogeneity are considered to be critical in understanding biological processes such as stem cell differentiation and cancer development. Recent advances in lab-on-a-chip techniques have allowed single-cell capture in microfluidic channels with the possibility of precise environmental control and high throughput of experiments with minimal usage of samples and reagents. In recent years, label-free techniques such as electrical impedance spectroscopy have emerged as a non-invasive approach to studying cell properties. In this study, we have designed and fabricated a microfluidic device that combines hydrodynamic trapping of single cells in pre-defined locations with the capability of running electrical impedance measurements within the same device. We have measured mouse embryonic stem cells (mESCs) at different states during differentiation (t=0 h, 24 h and 48 h) and quantitatively analysed the changes in electrical parameters of cells during differentiation. A marked increase in the magnitude of the cell impedance is found during cell differentiation, which can be attributed to an increase in cell size. The analysis of the measurements shows that the nucleus-to-cytoplasm ratio decreases during this process. The degree of cell heterogeneity is observed to be the highest when the cells are at the transition state (24 h), compare with cells at undifferentiated (0 h) and fully differentiated (48 h) states. The device enables highly efficient single cell trapping and provides sensitive, label-free electrical impedance measurements of individual cells, enabling the possibility of quantitatively analysing their physical state as well as studying the associated heterogeneity of a cell population. PMID:26963790

  16. 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.

  17. A temperature control method for shortening thermal cycling time to achieve rapid polymerase chain reaction (PCR) in a disposable polymer microfluidic device

    DEFF Research Database (Denmark)

    Bu, Minqiang; Perch-Nielsen, Ivan R.; Sørensen, Karen Skotte;

    2013-01-01

    We present a temperature control method capable of effectively shortening the thermal cycling time of polymerase chain reaction (PCR) in a disposable polymer microfluidic device with an external heater and a temperature sensor. The method employs optimized temperature overshooting and undershooting...

  18. 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.

  19. Fabrication and testing of a CoNiCu/Cu CPP-GMR nanowire-based microfluidic biosensor

    Science.gov (United States)

    Bellamkonda, Ramya; John, Tom; Mathew, Bobby; DeCoster, Mark; Hegab, Hisham; Davis, Despina

    2010-02-01

    Giant magneto resistance (GMR)-based microfluidic biosensors are used in applications involving the detection, analysis, enumeration and characterization of magnetic nano-particles attached to biological mediums such as antibodies and DNA. Here we introduce a novel multilayered CoNiCu/Cu nanowire GMR-based microfluidic biosensor. The current perpendicular to the plane of multilayers (CPP)-nanowires GMR was used as the core sensing material in the biosensor which responds to magnetic fields depending on the concentration and the flow velocity of bio-nano-magnetic fluids. The device was tested with different control solutions such as DI-water, mineral oil, phosphate buffered saline (PBS), ferrofluid, polystyrene superparamagnetic beads (PSB) and Dynabeads sheep anti-rabbit IgG. The nanowire array resistance decreased with an increase in the ferrofluid concentration, and a maximum 15.8% relative GMR was observed for the undiluted ferrofluid. The sensor was also responding differently to various ferrofluid flow rates. The GMR device showed variation in the output signal when the PSB and Dynabeads of different dilutions were pumped through it. When the tests were performed with pulsing potentials (150 mV and 200 mV), an increased GMR response was identified at higher voltages for PSB and Dynabeads sheep anti-rabbit IgG.

  20. Fabrication and testing of a CoNiCu/Cu CPP-GMR nanowire-based microfluidic biosensor

    International Nuclear Information System (INIS)

    Giant magneto resistance (GMR)-based microfluidic biosensors are used in applications involving the detection, analysis, enumeration and characterization of magnetic nano-particles attached to biological mediums such as antibodies and DNA. Here we introduce a novel multilayered CoNiCu/Cu nanowire GMR-based microfluidic biosensor. The current perpendicular to the plane of multilayers (CPP)-nanowires GMR was used as the core sensing material in the biosensor which responds to magnetic fields depending on the concentration and the flow velocity of bio-nano-magnetic fluids. The device was tested with different control solutions such as DI-water, mineral oil, phosphate buffered saline (PBS), ferrofluid, polystyrene superparamagnetic beads (PSB) and Dynabeads sheep anti-rabbit IgG. The nanowire array resistance decreased with an increase in the ferrofluid concentration, and a maximum 15.8% relative GMR was observed for the undiluted ferrofluid. The sensor was also responding differently to various ferrofluid flow rates. The GMR device showed variation in the output signal when the PSB and Dynabeads of different dilutions were pumped through it. When the tests were performed with pulsing potentials (150 mV and 200 mV), an increased GMR response was identified at higher voltages for PSB and Dynabeads sheep anti-rabbit IgG.