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Sample records for ppc microfluidic chips

  1. Purification and preconcentration of genomic DNA from whole cell lysates using photoactivated polycarbonate (PPC) microfluidic chips

    PubMed Central

    Witek, Małgorzata A.; Llopis, Shawn D.; Wheatley, Abigail; McCarley, Robin L.; Soper, Steven A.

    2006-01-01

    We discuss the use of a photoactivated polycarbonate (PPC) microfluidic chip for the solid-phase, reversible immobilization (SPRI) and purification of genomic DNA (gDNA) from whole cell lysates. The surface of polycarbonate was activated by UV radiation resulting in a photo-oxidation reaction, which produced a channel surface containing carboxylate groups. The gDNA was selectively captured on this photoactivated surface in an immobilization buffer, which consisted of 3% polyethylene glycol, 0.4 M NaCl and 70% ethanol. The methodology reported herein is similar to conventional SPRI in that surface-confined carboxylate groups are used for the selective immobilization of DNA; however, no magnetic beads or a magnetic field are required. As observed by UV spectroscopy, a load of ∼7.6 ± 1.6 µg/ml of gDNA was immobilized onto the PPC bed. The recovery of DNA following purification was estimated to be 85 ± 5%. The immobilization and purification assay using this PPC microchip could be performed within ∼25 min as follows: (i) DNA immobilization ∼6 min, (ii) chip washout with ethanol 10 min, and (iii) drying and gDNA desorption ∼6 min. The PPC microchip could also be used for subsequent assays with no substantial loss in recovery, no observable carryover and no need for ‘reactivation’ of the PC surface with UV light. PMID:16757572

  2. Active microfluidic mixer chip

    NASA Astrophysics Data System (ADS)

    Niu, Xize; Liu, Liyu; Wen, Weijia; Sheng, Ping

    2006-04-01

    We report the design and fabrication of a chaotic mixer based on the electrorheological (ER) fluid-controlled valves. The flow in the main channel is perturbed by liquid flow in orthogonal side channels, driven by hydrodynamic pulsating pumps. Each pulsating pump consists of a chamber with diaphragm plus two out-of-phase ER valves operating in a push-pull mode. All the valves, pumps, and mixing channels are integrated in one polydimethylsioxane chip. Mixing characteristics in the main channel are controlled by the strength and frequency of external electric fields applied on the ER fluid.

  3. Materials for microfluidic chip fabrication.

    PubMed

    Ren, Kangning; Zhou, Jianhua; Wu, Hongkai

    2013-11-19

    Through manipulating fluids using microfabricated channel and chamber structures, microfluidics is a powerful tool to realize high sensitive, high speed, high throughput, and low cost analysis. In addition, the method can establish a well-controlled microenivroment for manipulating fluids and particles. It also has rapid growing implementations in both sophisticated chemical/biological analysis and low-cost point-of-care assays. Some unique phenomena emerge at the micrometer scale. For example, reactions are completed in a shorter amount of time as the travel distances of mass and heat are relatively small; the flows are usually laminar; and the capillary effect becomes dominant owing to large surface-to-volume ratios. In the meantime, the surface properties of the device material are greatly amplified, which can lead to either unique functions or problems that we would not encounter at the macroscale. Also, each material inherently corresponds with specific microfabrication strategies and certain native properties of the device. Therefore, the material for making the device plays a dominating role in microfluidic technologies. In this Account, we address the evolution of materials used for fabricating microfluidic chips, and discuss the application-oriented pros and cons of different materials. This Account generally follows the order of the materials introduced to microfluidics. Glass and silicon, the first generation microfluidic device materials, are perfect for capillary electrophoresis and solvent-involved applications but expensive for microfabriaction. Elastomers enable low-cost rapid prototyping and high density integration of valves on chip, allowing complicated and parallel fluid manipulation and in-channel cell culture. Plastics, as competitive alternatives to elastomers, are also rapid and inexpensive to microfabricate. Their broad variety provides flexible choices for different needs. For example, some thermosets support in-situ fabrication of

  4. Microfluidic organs-on-chips.

    PubMed

    Bhatia, Sangeeta N; Ingber, Donald E

    2014-08-01

    An organ-on-a-chip is a microfluidic cell culture device created with microchip manufacturing methods that contains continuously perfused chambers inhabited by living cells arranged to simulate tissue- and organ-level physiology. By recapitulating the multicellular architectures, tissue-tissue interfaces, physicochemical microenvironments and vascular perfusion of the body, these devices produce levels of tissue and organ functionality not possible with conventional 2D or 3D culture systems. They also enable high-resolution, real-time imaging and in vitro analysis of biochemical, genetic and metabolic activities of living cells in a functional tissue and organ context. This technology has great potential to advance the study of tissue development, organ physiology and disease etiology. In the context of drug discovery and development, it should be especially valuable for the study of molecular mechanisms of action, prioritization of lead candidates, toxicity testing and biomarker identification. PMID:25093883

  5. Wax-bonding 3D microfluidic chips.

    PubMed

    Gong, Xiuqing; Yi, Xin; Xiao, Kang; Li, Shunbo; Kodzius, Rimantas; Qin, Jianhua; Wen, Weijia

    2010-10-01

    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 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 can realize bridge bonding between various materials, for example, paper, polymethylmethacrylate (PMMA) film, glass sheets, or metal plate. The 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 vacuating and venting the chip in a hot-water bath. To study the biocompatibility and applicability of the wax-based microfluidic chip, we tested the PCR compatibility with the chip materials first. Then we applied the wax-paper based microfluidic chip to HeLa cell electroporation (EP). 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 (GFP) recombinant Escherichia coli (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. PMID:20689865

  6. Laser bonding of multilayer polymer microfluidic chips

    NASA Astrophysics Data System (ADS)

    Lai, Jianjun; Yuan, Hui; Yi, Xin-Jian; Liu, Sheng

    2005-01-01

    Polymer microfluidic chips have stimulated great instrests in the field of biochemical and medical analysis due to their low prices, easy fabrication and biocompatibility. Recently multilayer microfluidic chips have been fabricated by adhesive bonding to form 3-D multilayer laminate. However adhesive bonding may introduce pollution as well as complexity in coating. A bonding system with compact diode laser is introduced and a novel method based on transparent bonding line for multilayer microfluidic chips is developed. This bonding method is based on transmission laser microwelding technique. In this method, a special colorless dye as laser absorber, thus transparent polymer sheets can be stacked and bonded layer by layer. Initial results and bonding performance have demonstrate the feasibility of this method.

  7. The processing technology of PMMA micro-fluidic chip

    NASA Astrophysics Data System (ADS)

    Mu, Lili; Rong, Li; Guo, Shuheng; Liu, Qiong

    2016-01-01

    In order to enrich the production method of micro-fluidic chip and simplify its processing technology, the paper discussed the double-sided adhesive layer for channel layer, with PMMA (polymethyl methacrylate) for fabrication of microfluidic chip with the cover plate and the bottom plate. Taking 40 mm (long) x 20 mm (wide) x 2.2 mm (thick) liquid drop to separate the microfluidic chip as an example, details the design and machining process of the chip. Experiments show that surface quality is high and processing speed is fast when using this technology to process the chip. Thus, it can realize the mass production of micro fluidic chip.

  8. Microfluidics for miniaturized laboratories on a chip.

    PubMed

    Franke, Thomas A; Wixforth, Achim

    2008-10-24

    Microfluidic systems promise solutions for high throughput and highly specific analysis for biology, medicine and chemistry while consuming only tiny amounts of reactants and space. On these lab-on-a-chip platforms often multiple physical effects such as electrokinetic, acoustic or capillary phenomena from various disciplines are exploited to gain the optimal functionality. The fluidics on these small length scales differ significantly from our experience of the macroscopic world. In this Review we survey some of the approaches and techniques to handle minute amounts of fluid volumes in microfluidic systems with special focus on surface acoustic wave driven fluidics, a technique developed in our laboratory. Here, we outline the basics of this technique and demonstrate, for example, how acoustic mixing and fluid actuation is realized. Furthermore we discuss the interplay of different physical effects in microfluidic systems and illustrate their usefulness for several applications. PMID:18932153

  9. Microfluidic distillation chip for methanol concentration detection.

    PubMed

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

    2016-03-17

    An integrated microfluidic distillation system is proposed for separating a mixed ethanol-methanol-water solution into its constituent components. The microfluidic chip is fabricated using a CO2 laser system and comprises a serpentine channel, a boiling zone, a heating zone, and a cooled collection chamber filled with de-ionized (DI) water. In the proposed device, the ethanol-methanol-water solution is injected into the microfluidic chip and driven through the serpentine channel and into the collection chamber by means of a nitrogen carrier gas. Following the distillation process, the ethanol-methanol vapor flows into the collection chamber and condenses into the DI water. The resulting solution is removed from the collection tank and reacted with a mixed indicator. Finally, the methanol concentration is inversely derived from the absorbance measurements obtained using a spectrophotometer. The experimental results show the proposed microfluidic system achieves an average methanol distillation efficiency of 97%. The practicality of the proposed device is demonstrated by detecting the methanol concentrations of two commercial fruit wines. It is shown that the measured concentration values deviate by no more than 3% from those obtained using a conventional bench top system. PMID:26920777

  10. Droplet Microfluidics for Chip-Based Diagnostics

    PubMed Central

    Kaler, Karan V. I. S.; Prakash, Ravi

    2014-01-01

    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. PMID:25490590

  11. Lensfree sensing on a microfluidic chip using plasmonic nanoapertures

    PubMed Central

    Khademhosseinieh, Bahar; Biener, Gabriel; Sencan, Ikbal; Su, Ting-Wei; Coskun, Ahmet F.; Ozcan, Aydogan

    2010-01-01

    We demonstrate lensfree on-chip sensing within a microfluidic channel using plasmonic nanoapertures that are illuminated by a partially coherent quasimonochromatic source. In this approach, lensfree diffraction patterns of metallic nanoapertures located at the bottom of a microfluidic channel are recorded using an optoelectronic sensor-array. These lensfree diffraction patterns can then be rapidly processed, using phase recovery techniques, to back propagate the optical fields to an arbitrary depth, creating digitally focused complex transmission patterns. Cross correlation of these patterns enables lensfree on-chip sensing of the local refractive index surrounding the near-field of the plasmonic nanoapertures. Based on this principle, we experimentally demonstrate lensfree sensing of refractive index changes as small as ∼2×10−3. This on-chip sensing approach could be quite useful for development of label-free microarray technologies by multiplexing thousands of plasmonic structures on the same microfluidic chip, which can significantly increase the throughput of sensing. PMID:21203381

  12. Microfluidic cell chips for high-throughput drug screening.

    PubMed

    Chi, Chun-Wei; Ahmed, Ah Rezwanuddin; Dereli-Korkut, Zeynep; Wang, Sihong

    2016-05-01

    The current state of screening methods for drug discovery is still riddled with several inefficiencies. Although some widely used high-throughput screening platforms may enhance the drug screening process, their cost and oversimplification of cell-drug interactions pose a translational difficulty. Microfluidic cell-chips resolve many issues found in conventional HTS technology, providing benefits such as reduced sample quantity and integration of 3D cell culture physically more representative of the physiological/pathological microenvironment. In this review, we introduce the advantages of microfluidic devices in drug screening, and outline the critical factors which influence device design, highlighting recent innovations and advances in the field including a summary of commercialization efforts on microfluidic cell chips. Future perspectives of microfluidic cell devices are also provided based on considerations of present technological limitations and translational barriers. PMID:27071838

  13. Various on-chip sensors with microfluidics for biological applications.

    PubMed

    Lee, Hun; Xu, Linfeng; Koh, Domin; Nyayapathi, Nikhila; Oh, Kwang W

    2014-01-01

    In this paper, we review recent advances in on-chip sensors integrated with microfluidics for biological applications. Since the 1990s, much research has concentrated on developing a sensing system using optical phenomena such as surface plasmon resonance (SPR) and surface-enhanced Raman scattering (SERS) to improve the sensitivity of the device. The sensing performance can be significantly enhanced with the use of microfluidic chips to provide effective liquid manipulation and greater flexibility. We describe an optical image sensor with a simpler platform for better performance over a larger field of view (FOV) and greater depth of field (DOF). As a new trend, we review consumer electronics such as smart phones, tablets, Google glasses, etc. which are being incorporated in point-of-care (POC) testing systems. In addition, we discuss in detail the current optical sensing system integrated with a microfluidic chip. PMID:25222033

  14. Various On-Chip Sensors with Microfluidics for Biological Applications

    PubMed Central

    Lee, Hun; Xu, Linfeng; Koh, Domin; Nyayapathi, Nikhila; Oh, Kwang W.

    2014-01-01

    In this paper, we review recent advances in on-chip sensors integrated with microfluidics for biological applications. Since the 1990s, much research has concentrated on developing a sensing system using optical phenomena such as surface plasmon resonance (SPR) and surface-enhanced Raman scattering (SERS) to improve the sensitivity of the device. The sensing performance can be significantly enhanced with the use of microfluidic chips to provide effective liquid manipulation and greater flexibility. We describe an optical image sensor with a simpler platform for better performance over a larger field of view (FOV) and greater depth of field (DOF). As a new trend, we review consumer electronics such as smart phones, tablets, Google glasses, etc. which are being incorporated in point-of-care (POC) testing systems. In addition, we discuss in detail the current optical sensing system integrated with a microfluidic chip. PMID:25222033

  15. Teaching microfluidic diagnostics using Jell-O(®) chips.

    PubMed

    Yang, Cheng Wei T; Lagally, Eric T

    2013-01-01

    Microfluidics has emerged as a versatile technology that has found many applications, including DNA chips, fuel cells, and diagnostics. As the field of microfluidic diagnostics grows, it is important to introduce the principles of this technology to young students and the general public. The objective of this project was to create a simple and effective method that could be used to teach key microfluidics concepts using easily accessible materials. Similar to the poly(dimethylsiloxane) soft lithography technique, a Jell-O(®) "chip" is produced by pouring a mixture of Jell-O(®) and gelatine solution into a mold, which is constructed using foam plate, coffee stirrers, and double-sided tape. The plate is transferred to a 4°C refrigerator for curing, and then the Jell-O(®) chip is peeled off for experimental demonstrations. Three types of chips have been fabricated with different molds: a JELLO mold, a Y-channel mold, and a pH-sensor mold. Using these devices, the basics of microfluidic diagnostics can be demonstrated in one or two class periods. The method described in this chapter provides teachers with a fast and inexpensive way to introduce this technology, and students with a fun and hands-on way to understand the basics of microfluidic diagnostics. PMID:23329433

  16. A novel microfluidic chip based on fiber sensor

    NASA Astrophysics Data System (ADS)

    Su, Bo; Duan, Guoteng; Han, Xue

    2013-08-01

    We have fabricated a novel microfluidic chip based on fiber sensor with casting PDMS method. The optical fiber is used to transmit excitation light, so the diameter of the excitation beam is decreased to 93μm. In order to improve the coupling efficiency of the excitation light in the fiber, the optical fiber collimation device is used to couple beam. The microfluidic chip consists of multimode optical fiber, PDMS cover slab and PDMS base slab. The mould of cover slab is made through twice exposal, however the base slab is achieved using once exposal only. The depths of microfluidic channel and optical fiber channel in the PDMS cover slab are 50μm and 90μm, respectively, and the optical fiber channel in the PDMS base slab is only 40μm. This design can make the centers of the microfluidic channel and the fiber channel in the same point, so the microfluidic channel and the optical fiber can be aimed at easily. In addition, the size of microfluidic channel depth is near the size of light spot of optical fiber, so the detection sensitivity is improved without using the optical focusing system. The detection system of the microfluidic chip is manufactured and it composed of high voltage modules, darkroom, LED light source, photomultiplier and data acquisition circuit, moreover, the software of the detection system is developed. The high voltage modules with four 2kV are used to control the sample amount in the separation channel, so the sensitivity is improved. The microfluidic chip is placed in the darkroom to avoid the interference of external light. The high brightness blue light emitting diode (LED) is used as excitation light sources for inducing fluorescence detection through coupling the LED light into the optical fiber. The photomultiplier is used to amplify the fluorescence signals and the function of data acquisition circuit is data collection and data processing. Under the control of software, the experiment process can be implemented easily. As an

  17. On-chip Microfluidic Multimodal Swimmer toward 3D Navigation

    NASA Astrophysics Data System (ADS)

    Barbot, Antoine; Decanini, Dominique; Hwang, Gilgueng

    2016-01-01

    Mobile microrobots have a promising future in various applications. These include targeted drug delivery, local measurement, biopsy or microassembly. Studying mobile microrobots inside microfluidics is an essential step towards such applications. But in this environment that was not designed for the robot, integration process and propulsion robustness still pose technological challenges. In this paper, we present a helical microrobot with three different motions, designed to achieve these goals. These motions are rolling, spintop motion and swimming. Through these multiple motions, microrobots are able to selectively integrate a chip through a microfluidic channel. This enables them to perform propulsion characterizations, 3D (Three Dimensional) maneuverability, particle cargo transport manipulation and exit from the chip. The microrobot selective integration inside microfluidics could lead to various in-vitro biologic or in-vivo biomedical applications.

  18. On-chip Microfluidic Multimodal Swimmer toward 3D Navigation

    PubMed Central

    Barbot, Antoine; Decanini, Dominique; Hwang, Gilgueng

    2016-01-01

    Mobile microrobots have a promising future in various applications. These include targeted drug delivery, local measurement, biopsy or microassembly. Studying mobile microrobots inside microfluidics is an essential step towards such applications. But in this environment that was not designed for the robot, integration process and propulsion robustness still pose technological challenges. In this paper, we present a helical microrobot with three different motions, designed to achieve these goals. These motions are rolling, spintop motion and swimming. Through these multiple motions, microrobots are able to selectively integrate a chip through a microfluidic channel. This enables them to perform propulsion characterizations, 3D (Three Dimensional) maneuverability, particle cargo transport manipulation and exit from the chip. The microrobot selective integration inside microfluidics could lead to various in-vitro biologic or in-vivo biomedical applications. PMID:26791433

  19. On-chip Microfluidic Multimodal Swimmer toward 3D Navigation.

    PubMed

    Barbot, Antoine; Decanini, Dominique; Hwang, Gilgueng

    2016-01-01

    Mobile microrobots have a promising future in various applications. These include targeted drug delivery, local measurement, biopsy or microassembly. Studying mobile microrobots inside microfluidics is an essential step towards such applications. But in this environment that was not designed for the robot, integration process and propulsion robustness still pose technological challenges. In this paper, we present a helical microrobot with three different motions, designed to achieve these goals. These motions are rolling, spintop motion and swimming. Through these multiple motions, microrobots are able to selectively integrate a chip through a microfluidic channel. This enables them to perform propulsion characterizations, 3D (Three Dimensional) maneuverability, particle cargo transport manipulation and exit from the chip. The microrobot selective integration inside microfluidics could lead to various in-vitro biologic or in-vivo biomedical applications. PMID:26791433

  20. Development of a microplate reader compatible microfluidic chip for ELISA.

    PubMed

    Hou, Fenghua; Zhang, Qin; Yang, Jianping; Li, Xinchun; Yang, Xiujuan; Wang, Shuping; Cheng, Zhiyi

    2012-08-01

    We report a novel microfluidic device use for sandwich enzyme-linked immunoassay assay (ELISA). The related procedures including the introduction of reagents, dilution and distribution of samples, as well as immobilization of enzyme can be readily carried out on a poly (dimethylsiloxane) (PDMS) chip. Particularly, this microfluidic chip comprising of two distinct parallel units, and has an identical dimension as a conventional microtiter plate, which offers access to the directly quantitative detection by the microplate reader. Gradient-concentration reacting solutions at six different concentrations level generated by the microfluidic channel network are simultaneously transported to 24 reaction chambers to form enzymatic products. Alkaline phosphatase (ALP), 4-methylumbelliferyl phosphate (4-MUP) and KH(2)PO(4) are used as enzyme-substrate-inhibitor model, to demonstrate the utility of the developed microchip-based enzyme inhibitor assay. Various conditions such as the surface treatment of chip channels, fluids velocities, substrate concentration, and buffer pH are investigated. The present microfluidic device for ELISA holds several advantages, for instance frugal usage of samples and reagents, less of operating time, favorably integrated configuration, ease of manipulation, and could be explored to a variety of high throughput drug screening. PMID:22526682

  1. The promise of macromolecular crystallization in microfluidic chips

    NASA Technical Reports Server (NTRS)

    van der Woerd, Mark; Ferree, Darren; Pusey, Marc

    2003-01-01

    Microfluidics, or lab-on-a-chip technology, is proving to be a powerful, rapid, and efficient approach to a wide variety of bioanalytical and microscale biopreparative needs. The low materials consumption, combined with the potential for packing a large number of experiments in a few cubic centimeters, makes it an attractive technique for both initial screening and subsequent optimization of macromolecular crystallization conditions. Screening operations, which require a macromolecule solution with a standard set of premixed solutions, are relatively straightforward and have been successfully demonstrated in a microfluidics platform. Optimization methods, in which crystallization solutions are independently formulated from a range of stock solutions, are considerably more complex and have yet to be demonstrated. To be competitive with either approach, a microfluidics system must offer ease of operation, be able to maintain a sealed environment over several weeks to months, and give ready access for the observation and harvesting of crystals as they are grown.

  2. On-chip microfluidic tuning of an optical microring resonator

    NASA Astrophysics Data System (ADS)

    Levy, Uriel; Campbell, Kyle; Groisman, Alex; Mookherjea, Shayan; Fainman, Yeshaiahu

    2006-03-01

    We describe the design, fabrication, and operation of a tunable optical filter based on a bus waveguide coupled to a microring waveguide resonator located inside a microchannel in a microfluidic chip. Liquid flowing in the microchannel constitutes the upper cladding of the waveguides. The refractive index of the liquid controls the resonance wavelengths and strength of coupling between the bus waveguide and the resonator. The refractive index is varied by on-chip mixing of two source liquids with different refractive indices. We demonstrate adjustment of the resonance by 2nm and tuning the filter to an extinction ratio of 37dB.

  3. A glass microfluidic chip adhesive bonding method at room temperature

    NASA Astrophysics Data System (ADS)

    Pan, Yu-Jen; Yang, Ruey-Jen

    2006-12-01

    This paper presents a novel method using UV epoxy resin for the bonding of glass blanks and patterned plates at room temperature. There is no need to use a high-temperature thermal fusion process and therefore avoid damaging temperature-sensitive metals in a microchip. The proposed technique has the further advantage that the sealed glass blanks and patterned plates can be separated by the application of adequate heat. In this way, the microchip can be opened, the fouling microchannels may be easily cleaned-up and the plates then re-bonded to recycle the microchip. The proposed sealing method is used to bond a microfluidic device, and the bonding strength is then investigated in a series of chemical resistance tests conducted in various chemicals. Leakage of solution was evaluated in a microfluidic chip using pressure testing to 1.792 × 102 kPa (26 psi), and the microchannel had no observable leak. Electrical leakage between channels was tested by comparing the resistances of two bonding methods, and the result shows no significant electrical leakage. The performance of the device obtained from the proposed bonding method is compared with that of the thermal fusion bonding technique for an identical microfluidic device. It is found that identical results are obtained under the same operating conditions. The proposed method provides a simple, quick and inexpensive method for sealing glass microfluidic chips.

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

    PubMed

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

    2012-02-01

    A miniaturized distillation system is presented for separating sulfurous acid (H(2)SO(3)) into sulfur dioxide (SO(2)) and water (H(2)O). The major components of the proposed system include a microfluidic distillation chip, a power control module, and a carrier gas pressure control module. The microfluidic chip is patterned using a commercial CO(2) laser and comprises a serpentine channel, a heating zone, a buffer zone, a cooling zone, and a collection tank. In the proposed device, the H(2)SO(3) solution is injected into the microfluidic chip and is separated into SO(2) and H(2)O via an appropriate control of the distillation time and temperature. The gaseous SO(2) is then transported into the collection chamber by the carrier gas and is mixed with DI water. Finally, the SO(2) concentration is deduced from the absorbance measurements obtained using a spectrophotometer. The experimental results show that a correlation coefficient of R(2) = 0.9981 and a distillation efficiency as high as 94.6% are obtained for H(2)SO(3) solutions with SO(2) concentrations in the range of 100-500 ppm. The SO(2) concentrations of two commercial red wines are successfully detected using the developed device. Overall, the results presented in this study show that the proposed system provides a compact and reliable tool for SO(2) concentration measurement purposes. PMID:22159042

  5. System-level simulation of liquid filling in microfluidic chips.

    PubMed

    Song, Hongjun; Wang, Yi; Pant, Kapil

    2011-06-01

    Liquid filling in microfluidic channels is a complex process that depends on a variety of geometric, operating, and material parameters such as microchannel geometry, flow velocity∕pressure, liquid surface tension, and contact angle of channel surface. Accurate analysis of the filling process can provide key insights into the filling time, air bubble trapping, and dead zone formation, and help evaluate trade-offs among the various design parameters and lead to optimal chip design. However, efficient modeling of liquid filling in complex microfluidic networks continues to be a significant challenge. High-fidelity computational methods, such as the volume of fluid method, are prohibitively expensive from a computational standpoint. Analytical models, on the other hand, are primarily applicable to idealized geometries and, hence, are unable to accurately capture chip level behavior of complex microfluidic systems. This paper presents a parametrized dynamic model for the system-level analysis of liquid filling in three-dimensional (3D) microfluidic networks. In our approach, a complex microfluidic network is deconstructed into a set of commonly used components, such as reservoirs, microchannels, and junctions. The components are then assembled according to their spatial layout and operating rationale to achieve a rapid system-level model. A dynamic model based on the transient momentum equation is developed to track the liquid front in the microchannels. The principle of mass conservation at the junction is used to link the fluidic parameters in the microchannels emanating from the junction. Assembly of these component models yields a set of differential and algebraic equations, which upon integration provides temporal information of the liquid filling process, particularly liquid front propagation (i.e., the arrival time). The models are used to simulate the transient liquid filling process in a variety of microfluidic constructs and in a multiplexer, representing a

  6. High Voltage Dielectrophoretic and Magnetophoretic Hybrid Integrated Circuit / Microfluidic Chip

    PubMed Central

    Issadore, David; Franke, Thomas; Brown, Keith A.; Hunt, Thomas P.; Westervelt, Robert M.

    2010-01-01

    A hybrid integrated circuit (IC) / microfluidic chip is presented that independently and simultaneously traps and moves microscopic objects suspended in fluid using both electric and magnetic fields. This hybrid chip controls the location of dielectric objects, such as living cells and drops of fluid, on a 60 × 61 array of pixels that are 30 × 38 μm2 in size, each of which can be individually addressed with a 50 V peak-to-peak, DC to 10 MHz radio frequency voltage. These high voltage pixels produce electric fields above the chip’s surface with a magnitude , resulting in strong dielectrophoresis (DEP) forces . Underneath the array of DEP pixels there is a magnetic matrix that consists of two perpendicular sets of 60 metal wires running across the chip. Each wire can be sourced with 120 mA to trap and move magnetically susceptible objects using magnetophoresis (MP). The DEP pixel array and magnetic matrix can be used simultaneously to apply forces to microscopic objects, such as living cells or lipid vesicles, that are tagged with magnetic nanoparticles. The capabilities of the hybrid IC / microfluidic chip demonstrated in this paper provide important building blocks for a platform for biological and chemical applications. PMID:20625468

  7. Microfluidic-chip platform for cell sorting

    NASA Astrophysics Data System (ADS)

    Malik, Sarul; Balyan, Prerna; Akhtar, J.; Agarwal, Ajay

    2016-04-01

    Cell sorting and separation are considered to be very crucial preparatory steps for numerous clinical diagnostics and therapeutics applications in cell biology research arena. Label free cell separation techniques acceptance rate has been increased to multifold by various research groups. Size based cell separation method focuses on the intrinsic properties of the cell which not only avoids clogging issues associated with mechanical and centrifugation filtration methods but also reduces the overall cost for the process. Consequentially flow based cell separation method for continuous flow has attracted the attention of millions. Due to the realization of structures close to particle size in micro dimensions, the microfluidic devices offer precise and rapid particle manipulation which ultimately leads to an extraordinary cell separation results. The proposed microfluidic device is fabricated to separate polystyrene beads of size 1 µm, 5 µm, 10 µm and 20 µm. The actual dimensions of blood corpuscles were kept in mind while deciding the particle size of polystyrene beads which are used as a model particles for study.

  8. Microfluidic-Based sample chips for radioactive solutions

    SciTech Connect

    Tripp, J. L.; Law, J. D.; Smith, T. E.; Rutledge, V. J.; Bauer, W. F.; Ball, R. D.; Hahn, P. A.

    2015-01-01

    Historical nuclear fuel cycle process sampling techniques required sample volumes ranging in the tens of milliliters. The radiation levels experienced by analytical personnel and equipment, in addition to the waste volumes generated from analysis of these samples, have been significant. These sample volumes also impacted accountability inventories of required analytes during process operations. To mitigate radiation dose and other issues associated with the historically larger sample volumes, a microcapillary sample chip was chosen for further investigation. The ability to obtain microliter volume samples coupled with a remote automated means of sample loading, tracking, and transporting to the analytical instrument would greatly improve analytical efficiency while reducing both personnel exposure and radioactive waste volumes. Sample chip testing was completed to determine the accuracy, repeatability, and issues associated with the use of microfluidic sample chips used to supply µL sample volumes of lanthanide analytes dissolved in nitric acid for introduction to an analytical instrument for elemental analysis.

  9. Surface enhanced Raman spectroscopy for microfluidic pillar arrayed separation chips

    SciTech Connect

    Taylor, Lisa; Kirchner, Teresa B; Lavrik, Nickolay V; Sepaniak, Michael

    2012-01-01

    Numerous studies have addressed the challenges of implementing miniaturized microfluidic platforms for chemical and biological separation applications. However, the integration of real time detection schemes capable of providing valuable sample information under continuous, ultra low volume flow regimes has not fully been addressed. In this report we present a chip based chromatography system comprising of a pillar array separation column followed by a reagent channel for passive mixing of a silver colloidal solution into the eluent stream to enable surface enhanced Raman spectroscopy (SERS) detection. Our design is the first integrated chip based microfluidic device to combine pressure driven separation capability with real time SERS detection. With this approach we demonstrate the ability to collect distinctive SERS spectra with or without complete resolution of chromatographic bands. Computational fluidic dynamic (CFD) simulations are used to model the diffusive mixing behavior and velocity profiles of the two confluent streams in the microfluidic channels. We evaluate the SERS spectral band intensity and chromatographic efficiency of model analytes with respect to kinetic factors as well as signal acquisition rates. Additionally, we discuss the use of a pluronic modified silver colloidal solution as a means of eliminating contamination generally caused by nanoparticle adhesion to channel surfaces.

  10. Multi-layer microfluidic glass chips for microanalytical applications.

    PubMed

    Daridon, A; Fascio, V; Lichtenberg, J; Wütrich, R; Langen, H; Verpoorte, E; de Rooij, N F

    2001-09-01

    A new, versatile architecture is presented for microfluidic devices made entirely from glass, for use with reagents which would prove highly corrosive for silicon. Chips consist of three layers of glass wafers bonded together by fusion bonding. On the inside wafer faces a network of microfluidic channels is created by photolithography and wet chemical etching. Low dead-volume fluidic connections between the layers are fabricated by spark-assisted etching (SAE), a computer numerical controlled (CNC)-like machining technique new to microfluidic system fabrication. This method is also used to form a vertical, long path-length, optical cuvette through the middle wafer for optical absorbance detection of low-concentration compounds. Advantages of this technique compared with other, more standard, methods are discussed. When the new glass-based device for flow-injection analysis of ammonia was compared with our first-generation chips based on silicon micromachining, concentration sensitivity was higher, because of the longer path-length of the optical cuvette. The dependence of dispersion on velocity profile and on channel cross-sectional geometry is discussed. The rapid implementation of the devices for an organic synthesis reaction, the Wittig reaction, is also briefly described. PMID:11678200

  11. Polydimethylsiloxane-based conducting composites and their applications in microfluidic chip fabrication

    PubMed Central

    Gong, Xiuqing; Wen, Weijia

    2009-01-01

    This paper reviews the design and fabrication of polydimethylsiloxane (PDMS)-based conducting composites and their applications in microfluidic chip fabrication. Owing to their good electrical conductivity and rubberlike elastic characteristics, these composites can be used variously in soft-touch electronic packaging, planar and three-dimensional electronic circuits, and in-chip electrodes. Several microfluidic components fabricated with PDMS-based composites have been introduced, including a microfluidic mixer, a microheater, a micropump, a microdroplet controller, as well as an all-in-one microfluidic chip. PMID:19693388

  12. Microfluidic Chip Coupled with Thermal Desorption Atmospheric Pressure Ionization Mass Spectrometry

    PubMed Central

    Chang, Chia-Hsien; Chen, Tsung-Yi; Chen, Yu-Chie

    2014-01-01

    Microfluidic chips have been used as platforms for a diversity of research purposes such as for separation and micro-reaction. One of the suitable detectors for microfluidic chip is mass spectrometry. Because microfluidic chips are generally operated in an open air condition, mass spectrometry coupled with atmospheric pressure ion sources can suit the requirement with minimum compromise. In this study, we develop a new interface to couple a microfluidic chip with mass spectrometry. A capillary tip coated with a layer of graphite, capable of absorbing energy of near-infrared (NIR) light is used to interface microfluidic chip with mass spectrometry. An NIR laser diode (λ=808 nm) is used to irradiate the capillary tip for assisting the generation of spray from the eluent of the microfluidic chip. An electrospray is provided to fuse with the spray generated from the microfluidic chip for post-ionization. Transesterification is used as the example to demonstrate the feasibility of using this interface to couple microfluidic chip with mass spectrometry. PMID:26839753

  13. Bonding of glass microfluidic chips at room temperatures.

    PubMed

    Jia, Zhi-Jian; Fang, Qun; Fang, Zhao-Lun

    2004-09-15

    A simple, room-temperature bonding process was developed for the fabrication of glass microfluidic chips. High-quality bonding with high yields (>95%) was achieved without the requirement of clean room facilities, programmed high-temperature furnaces, pressurized water sources, adhesives, or pressurizing weights. The plates to be bonded were sequentially prewashed with acetone, detergent, high-flow-rate (10-20 m/s) tap water, and absolute ethyl alcohol and were soaked in concentrated sulfuric acid for 8-12 h. The plates were again washed in high-flow-rate tap water for 5 min and, finally, with demineralized water. The plates were bonded by bringing the cleaned surfaces into close contact under a continuous flow of demineralized water and air-dried at room temperature for more than 3 h. This bonding process features simple operation, good smoothness of the plate surface, and high bonding yield. The procedures can be readily applied in any routine laboratory. The bonding strength of glass chips thus produced, measured using a shear force testing procedure, was higher than 6 kg/cm(2). The mechanism for the strong bonding strength is presumably related to the formation of a hydrolyzed layer on the plate surfaces after soaking the substrates in acid or water for extended periods. Microfluidic chips bonded by the above procedure were tested in the CE separation of fluorescein isothiocyanate-labeled amino acids. PMID:15362926

  14. A microwave resonator integrated on a polymer microfluidic chip

    NASA Astrophysics Data System (ADS)

    Kiss, S. Z.; Rostas, A. M.; Heidinger, L.; Spengler, N.; Meissner, M. V.; MacKinnon, N.; Schleicher, E.; Weber, S.; Korvink, J. G.

    2016-09-01

    We describe a novel stacked split-ring type microwave (MW) resonator that is integrated into a 10 mm by 10 mm sized microfluidic chip. A straightforward and scalable batch fabrication process renders the chip suitable for single-use applications. The resonator volume can be conveniently loaded with liquid sample via microfluidic channels patterned into the mid layer of the chip. The proposed MW resonator offers an alternative solution for compact in-field measurements, such as low-field magnetic resonance (MR) experiments requiring convenient sample exchange. A microstrip line was used to inductively couple MWs into the resonator. We characterised the proposed resonator topology by electromagnetic (EM) field simulations, a field perturbation method, as well as by return loss measurements. Electron paramagnetic resonance (EPR) spectra at X-band frequencies were recorded, revealing an electron-spin sensitivity of 3.7 ·1011spins ·Hz - 1 / 2G-1 for a single EPR transition. Preliminary time-resolved EPR experiments on light-induced triplet states in pentacene were performed to estimate the MW conversion efficiency of the resonator.

  15. Microfluidic Chip for the Photocatalytic Production of Active Chlorine.

    PubMed

    Elmas, Sait; Ambroz, Filip; Chugh, Dipankar; Nann, Thomas

    2016-05-17

    Active chlorine is the most powerful microbicidal reagent in swimming pools, potable water, hospitals, and medical surgeries. Its production mainly relies on reactive inorganic intermediates and electrochemical methods that involve undesired waste products and high energy as well as material costs. In this study, we fabricated a low-cost chip based on sputter-coated thin films of silver (Ag) that acted as recyclable and effective photoelectrode for the photocatalytic production of active chlorine (HOCl) from aqueous media and artificial sunlight. The photoelectrode was electrochemically activated to AgCl at low overpotentials between 0.2 and 0.4 V vs Ag|AgCl (3 M KCl) and photocatalytically reduced to Ag(0) for 15 consecutive cycles, showing the electrode still being active. However, because of poor adhesion properties on the selected substrates, degradation effects were observed over time. Furthermore, the Ag@AgCl photoelectrode was integrated into a microfluidic chip, and we showed for the first time a light-driven microfluidic chip generating a constant stream of active chlorine. PMID:27115714

  16. A microwave resonator integrated on a polymer microfluidic chip.

    PubMed

    Kiss, S Z; Rostas, A M; Heidinger, L; Spengler, N; Meissner, M V; MacKinnon, N; Schleicher, E; Weber, S; Korvink, J G

    2016-09-01

    We describe a novel stacked split-ring type microwave (MW) resonator that is integrated into a 10mm by 10mm sized microfluidic chip. A straightforward and scalable batch fabrication process renders the chip suitable for single-use applications. The resonator volume can be conveniently loaded with liquid sample via microfluidic channels patterned into the mid layer of the chip. The proposed MW resonator offers an alternative solution for compact in-field measurements, such as low-field magnetic resonance (MR) experiments requiring convenient sample exchange. A microstrip line was used to inductively couple MWs into the resonator. We characterised the proposed resonator topology by electromagnetic (EM) field simulations, a field perturbation method, as well as by return loss measurements. Electron paramagnetic resonance (EPR) spectra at X-band frequencies were recorded, revealing an electron-spin sensitivity of 3.7·10(11)spins·Hz(-1/2)G(-1) for a single EPR transition. Preliminary time-resolved EPR experiments on light-induced triplet states in pentacene were performed to estimate the MW conversion efficiency of the resonator. PMID:27497077

  17. A microfluidic chip for studying the reproduction of Enteromorpha prolifera.

    PubMed

    Xu, Zhixuan; Liu, Qi; Zhang, Xinlian; Huang, Xuxiong; He, Peimin; Liu, Sixiu; Sui, Guodong

    2016-11-01

    In recent years, green tides caused by water eutrophication, has brought serious environmental problems. Enteromorpha prolifera (E. prolifera), an opportunistic macroalgae, is one of the main source contributing to the formation of green tides. It has been estimated that the excessive growth of E. prolifera is closely related to various reproductive ways of germ cells which are at the micrometer scale. Here we report a microfluidic device named Germ Cell Capture Chip (GCChip) to investigate the E. prolifera reproductive mechanism. GCChip integrates the functions of algal growing, and the release, capture and selective culture of germ cells. Automatic separation and capture of germ cells on the chip allows to study germ cells' response to different stimuli. The novel device greatly facilitates long-term live-cell imaging at cellular resolution and implements the rapid and accurate exchange of growth medium without manual intervention. Results showed that the starting time of germ cell releases were earlier on the chip than that of traditional experiments with more concentrated breakout. Moreover, GCChip can be widely applied on the study of other algae. The study of algae growth process, including the elongation of somatic cell, the generation, and the release of reproductive cells, can all be improved by using this microfluidic platform. PMID:27591653

  18. ITP of lanthanides in microfluidic PMMA chip.

    PubMed

    Cong, Yongzheng; Bottenus, Danny; Liu, Bingwen; Clark, Sue B; Ivory, Cornelius F

    2014-03-01

    An ITP separation of eight lanthanides on a serpentine PMMA microchip with a tee junction and a 230-mm-long serpentine channel is described. The cover of the PMMA chip is 175 μm thick so that a C(4) D in microchip mode can be used to detect the lanthanides as they migrate through the microchannel. Acetate and α-hydroxyisobutyric acid are used as complexing agents to increase the electrophoretic mobility difference between the lanthanides. Eight lanthanides are concentrated within ∼ 6 min by ITP in the microchip using 10 mM ammonium acetate at pH 4.5 as the leading electrolyte and 10 mM acetic acid at ∼ pH 3.0 as the terminating electrolyte. In addition, a 2D numerical simulation of the lanthanides undergoing ITP in the microchip is compared with experimental results using COMSOL Multiphysics v4.3a. PMID:24258617

  19. Pumpless steady-flow microfluidic chip for cell culture.

    PubMed

    Marimuthu, Mohana; Kim, Sanghyo

    2013-06-15

    The current research engineered a pumpless energy-efficient microfluidic perfusion cell culture chip that works by modifying the basic gravity-driven siphon flow using an intravenous (IV) infusion set as a conventional, inexpensive, and sterile tool. The IV set was modified to control the constant hydrostatic head difference, thereby maintaining the steady flow rate medium perfusion. The micro-bioreactor chip demonstrated flexibility in controlling a wide range of flow rates from 0.1 to 10ml/min, among which 1- and 5-ml/min flow rates were examined as suitable shear flows for long-term dermal fibroblast cell culture, paving the way for artificial skin development. PMID:23453976

  20. Preparation and validation of low cost microfluidic chips using a shrinking approach.

    PubMed

    Focaroli, S; Mazzitelli, S; Falconi, M; Luca, G; Nastruzzi, C

    2014-10-21

    The present paper describes the production of microfluidic chips using an approach based on shrinkable biocompatible polymers (i.e. agarose) for the production of size controlled microfluidic channels. In addition, all steps of chip production were carried out using an inexpensive approach that uses low cost chemicals and equipment. The produced chips were then validated by producing monodisperse polymeric microparticles for drug delivery and hydrogel microfibers for cell embedding. PMID:25144915

  1. The Promise of Macromolecular Crystallization in Micro-fluidic Chips

    NASA Technical Reports Server (NTRS)

    vanderWoerd, Mark; Ferree, Darren; Pusey, Marc

    2003-01-01

    Micro-fluidics, or lab on a chip technology, is proving to be a powerful, rapid, and efficient approach to a wide variety of bio-analytical and microscale bio-preparative needs. The low materials consumption, combined with the potential for packing a large number of experiments in a few cubic centimeters, makes it an attractive technique for both initial screening and subsequent optimization of macromolecular crystallization conditions. Screening operations, which require equilibrating macromolecule solution with a standard set of premixed solutions, are relatively straightforward and have been successfully demonstrated in a micro-fluidics platform. More complex optimization methods, where crystallization solutions are independently formulated from a range of stock solutions, are considerably more complex and have yet to be demonstrated. To be competitive with either approach, a micro-fluidics system must offer ease of operation, be able to maintain a sealed environment over several weeks to months, and give ready access for the observation of crystals as they are grown.

  2. Flexible packaging of solid-state integrated circuit chips with elastomeric microfluidics

    NASA Astrophysics Data System (ADS)

    Zhang, Bowei; Dong, Quan; Korman, Can E.; Li, Zhenyu; Zaghloul, Mona E.

    2013-01-01

    A flexible technology is proposed to integrate smart electronics and microfluidics all embedded in an elastomer package. The microfluidic channels are used to deliver both liquid samples and liquid metals to the integrated circuits (ICs). The liquid metals are used to realize electrical interconnects to the IC chip. This avoids the traditional IC packaging challenges, such as wire-bonding and flip-chip bonding, which are not compatible with current microfluidic technologies. As a demonstration we integrated a CMOS magnetic sensor chip and associate microfluidic channels on a polydimethylsiloxane (PDMS) substrate that allows precise delivery of small liquid samples to the sensor. Furthermore, the packaged system is fully functional under bending curvature radius of one centimetre and uniaxial strain of 15%. The flexible integration of solid-state ICs with microfluidics enables compact flexible electronic and lab-on-a-chip systems, which hold great potential for wearable health monitoring, point-of-care diagnostics and environmental sensing among many other applications.

  3. Polymethylhydrosiloxane (PMHS) as a functional material for microfluidic chips

    NASA Astrophysics Data System (ADS)

    Lee, S. J.; Goedert, M.; Matyska, M. T.; Ghandehari, E. M.; Vijay, M.; Pesek, J. J.

    2008-02-01

    Polymethylhydrosiloxane (PMHS) has been investigated as a candidate material for microfluidic chips. The ability to modify the surface of PMHS by hydrosilation is particularly advantageous for separation processes. The chemical modification of PMHS is verified by diffuse reflectance infrared Fourier transform (DRIFT) analysis, and the modified PMHS is shown to be stable when exposed to extreme pH conditions between 2 and 9. Spectrophotometer measurements show that PMHS exhibits over 40% transmittance for ultraviolet (UV) wavelength as low as 220 nm, indicating viability for sensor applications based on UV absorption. The UV transmittance is furthermore observed to be insensitive to thickness for specimens tested between 1.6 mm and 6.4 mm thick. Full curing of PMHS liquid resin occurs between 48 and 72 h at 110 °C with no secondary additives. Casting of microscale features is achieved by using soft lithography methods similar to established techniques for fabrication based on polydimethylsiloxane (PDMS). Microchannels approximately 100 µm wide and 50 µm deep are also demonstrated by carbon dioxide laser ablation, with uniform channels produced using an energy dose of 0.2 mJ mm-1 with respect to line length. Other basic functional requirements for microfluidic chips are discussed, including the ability to bond PMHS substrates by plasma treatment.

  4. Fracture strength of glass chips for high-pressure microfluidics

    NASA Astrophysics Data System (ADS)

    Andersson, Martin; Hjort, Klas; Klintberg, Lena

    2016-09-01

    High-pressure microfluidics exposes new areas in chemistry. In this paper, the reliability of transparent borosilicate glass chips is investigated. Two designs of circular cavities are used for fracture strength tests, either 1.6 mm wide with rounded corners to the fluid inlets, or 2.0 mm wide with sharp inlet corners. Two kinds of tests are done, either short-term, e.g. pressurization to fracture at room temperature, or long-term, with fracture at constant pressurization for up to one week, in the temperature region 11–125 °C. The speed of crack fronts is measured using a high-speed camera. Results show fracture stresses in the range of 129 and 254 MPa for short-term measurements. Long-term measurements conclude the presences of a temperature and stress dependent delayed fracture. For a reliability of one week at 11–38 °C, a pressure limit is found at the lower end of the short-term measurements, or 15% lower than the average. At 80 °C, this pressure limit is 45% lower. Crack speeds are measured to be 10‑5 m s‑1 during short-term fracture. These measurements are comparable with estimations based on slow crack growth and show that the growth affects the reliability of glass chips. This effect is strongly affected by high temperatures, thus lowers the operating window of high-pressure glass microfluidic devices.

  5. Microfluidics without channels: highly-flexible synthesis on a digital-microfluidic chip for production of diverse PET tracers

    SciTech Connect

    Van Dam, Robert Michael

    2010-09-01

    Positron emission tomography (PET) imaging is used for fundamental studies of living biological organisms and microbial ecosystems in applications ranging from biofuel production to environmental remediation to the study, diagnosis, and treatment monitoring of human disease. Routine access to PET imaging, to monitor biochemical reactions in living organisms in real time, could accelerate a broad range of research programs of interest to DOE. Using PET requires access to short-lived radioactive-labeled compounds that specifically probe the desired living processes. The overall aims of this project were to develop a miniature liquid-handling technology platform (called “microfluidics”) that increases the availability of diverse PET probes by reducing the cost and complexity of their production. Based on preliminary experiments showing that microfluidic chips can synthesis such compounds, we aimed to advance this technology to improve its robustness, increase its flexibility for a broad range of probes, and increase its user-friendliness. Through the research activities of this project, numerous advances were made; Tools were developed to enable the visualization of radioactive materials within microfluidic chips; Fundamental advances were made in the microfluidic chip architecture and fabrication process to increase its robustness and reliability; The microfluidic chip technology was shown to produce useful quantities of an example PET probes, and methods to further increase the output were successfully pursued; A “universal” chip was developed that could produce multiple types of PET probes, enabling the possibility of “on demand” synthesis of different probes; and Operation of the chip was automated to ensure minimal radiation exposure to the operator Based on the demonstrations of promising technical feasibility and performance, the microfluidic chip technology is currently being commercialized. It is anticipated that costs of microfluidic chips can be

  6. A microfluidic chip with hydrodynamic traps for in vitro microscopic investigations of single cells

    NASA Astrophysics Data System (ADS)

    Kukhtevich, I. V.; Belousov, K. I.; Bukatin, A. S.; Dubina, M. V.; Evstrapov, A. A.

    2015-03-01

    The results on making a microfluidic chip for in vitro microscopic investigations of single cells are presented. Numerical simulation of the motion trajectories of microparticles makes it possible to determine the geometry of hydrodynamic traps, their number, and the trap arrangement in a reaction chamber. According to the developed design, microfluidic chips were fabricated from a SU-8 photoresist by photolithography. The microfluidic chips have been tested to prove their operating capacity for isolating and holding K562 human myeloid leukemia cells from a sample flow and their subsequent investigation by confocal laser scanning microscopy.

  7. Microfluidic-Based sample chips for radioactive solutions

    DOE PAGESBeta

    Tripp, J. L.; Law, J. D.; Smith, T. E.; Rutledge, V. J.; Bauer, W. F.; Ball, R. D.; Hahn, P. A.

    2015-01-01

    Historical nuclear fuel cycle process sampling techniques required sample volumes ranging in the tens of milliliters. The radiation levels experienced by analytical personnel and equipment, in addition to the waste volumes generated from analysis of these samples, have been significant. These sample volumes also impacted accountability inventories of required analytes during process operations. To mitigate radiation dose and other issues associated with the historically larger sample volumes, a microcapillary sample chip was chosen for further investigation. The ability to obtain microliter volume samples coupled with a remote automated means of sample loading, tracking, and transporting to the analytical instrument wouldmore » greatly improve analytical efficiency while reducing both personnel exposure and radioactive waste volumes. Sample chip testing was completed to determine the accuracy, repeatability, and issues associated with the use of microfluidic sample chips used to supply µL sample volumes of lanthanide analytes dissolved in nitric acid for introduction to an analytical instrument for elemental analysis.« less

  8. Mapping three-dimensional temperature in microfluidic chip

    PubMed Central

    Wu, Jinbo; Kwok, Tsz Yan; Li, Xiaolin; Cao, Wenbin; Wang, Yu; Huang, Junying; Hong, Yaying; Zhang, Dongen; Wen, Weijia

    2013-01-01

    Three-dimensional (3D) temperature mapping method with high spatial resolution and acquisition rate is of vital importance in evaluating thermal processes in micro-environment. We have synthesized a new temperature-sensitive functional material (Rhodamine B functionalized Polydimethylsiloxane). By performing optical sectioning of this material, we established an advanced method for visualizing the micro-scale 3D thermal distribution inside microfluidic chip with down to 10 ms temporal resolution and 2 ~ 6°C temperature resolution depending the capture parameters. This method is successfully applied to monitor the local temperature variation throughout micro-droplet heat transfer process and further reveal exothermic nanoliter droplet reactions to be unique and milder than bench-top experiment. PMID:24276475

  9. Numerical simulation of isolation of cancer cells in a microfluidic chip

    NASA Astrophysics Data System (ADS)

    Djukic, T.; Topalovic, M.; Filipovic, N.

    2015-08-01

    Cancer is a disease that is characterized by the uncontrolled increase of numbers of cells. Circulating tumour cells (CTCs) are separated from the primary tumor, circulate in the bloodstream and form metastases. Circulating tumor cells can be identified in the blood of a patient by taking a blood sample. Microfluidic chips are a new technique that is used to isolate these cells from the blood sample. In this paper a numerical model is presented that is able to simulate the motion of individual cells through a microfluidic chip. The proposed numerical model gives very valuable insight into the processes happening within a microfluidic chip. The accuracy of the proposed model is compared with experimental results. The experimental setup that is described in literature is used to create identical geometrical domains and define simulation parameters. A good agreement of experimental and numerical results demonstrates that the proposed model can be successfully used to simulate complex behaviour of CTCs inside microfluidic chips.

  10. A world-to-chip socket for microfluidic prototype development.

    PubMed

    Yang, Zhen; Maeda, Ryutaro

    2002-10-01

    We report a prototype for a standard connector between a microfluidic chip and the macroworld. This prototype is the first to demonstrate a fully functioning socket for a microchip to access the outside world by means of fluids, data, and energy supply, as well as providing process visibility. It has 20 channels for the input and output of liquids or gases, as well as compressed air or vacuum lines for pneumatic power lines. It also contains 42 pins for electrical signals and power. All these connections were designed in a planar configuration with linear orthogonal arrays. The vertical space was opened for optical measurement and evaluation. The die (29.1 mm x 27.5 mm x 0.9 mm) can be easily mounted and dismounted from the socket. No adhesives or solders are used at any contact points. The pressure limit for the connection of working fluids was 0.2 MPa and the current limit for the electrical connections was 1 A. This socket supports both serial and parallel processing applications. It exhibits great potential for developing microfluidic systems efficiently. PMID:12412114

  11. Fish-on-a-chip: microfluidics for zebrafish research.

    PubMed

    Yang, Fan; Gao, Chuan; Wang, Ping; Zhang, Guo-Jun; Chen, Zuanguang

    2016-03-23

    High-efficiency zebrafish (embryo) handling platforms are crucially needed to facilitate the deciphering of the increasingly expanding vertebrate-organism model values. However, the manipulation platforms for zebrafish are scarce and rely mainly on the conventional "static" microtiter plates or glass slides with rigid gel, which limits the dynamic, three-dimensional (3D), tissue/organ-oriented information acquisition from the intact larva with normal developmental dynamics. In addition, these routine platforms are not amenable to high-throughput handling of such swimming multicellular biological entities at the single-organism level and incapable of precisely controlling the growth microenvironment by delivering stimuli in a well-defined spatiotemporal fashion. Recently, microfluidics has been developed to address these technical challenges via tailor-engineered microscale structures or structured arrays, which integrate with or interface to functional components (e.g. imaging systems), allowing quantitative readouts of small objects (zebrafish larvae and embryos) under normal physiological conditions. Here, we critically review the recent progress on zebrafish manipulation, imaging and phenotype readouts of external stimuli using these microfluidic tools and discuss the challenges that confront these promising "fish-on-a-chip" technologies. We also provide an outlook on future potential trends in this field by combining with bionanoprobes and biosensors. PMID:26923141

  12. Microfluidic device (ExoChip) for on-chip isolation, quantification and characterization of circulating exosomes.

    PubMed

    Kanwar, Shailender Singh; Dunlay, Christopher James; Simeone, Diane M; Nagrath, Sunitha

    2014-06-01

    Membrane bound vesicles, including microvesicles and exosomes, are secreted by both normal and cancerous cells into the extracellular space and in blood circulation. These circulating extracellular vesicles (cirEVs) and exosomes in particular are recognized as a potential source of disease biomarkers. However, to exploit the use of circulatory exosomes as a biomarker, a rapid, high-throughput and reproducible method is required for their isolation and molecular analysis. We have developed a simple, low cost microfluidic-based platform to isolate cirEVs enriched in exosomes directly from blood serum allowing simultaneous capture and quantification of exosomes in a single device. To capture specific exosomes, we employed "ExoChip", a microfluidic device fabricated in polydimethylsiloxane (PDMS) and functionalized with antibodies against CD63, an antigen commonly overexpressed in exosomes. Subsequent staining with a fluorescent carbocyanine dye (DiO) that specifically labels the exosomes, we quantitated exosomes using a standard plate-reader. Ten independent ExoChip experiments performed using serum obtained from five pancreatic cancer patients and five healthy individuals revealed a statistically significant increase (2.34 ± 0.31 fold, p < 0.001) in exosomes captured in cancer patients when compared to healthy individuals. Exosomal origins of ExoChip immobilized vesicles were further confirmed using immuno-electron-microscopy and Western blotting. In addition, we demonstrate the ability of ExoChip to recover exosomes with intact RNA enabling profiling of exosomal-microRNAs through openarray analysis, which has potential applications in biomarker discovery. Based on our findings, ExoChip is a well suited platform to be used as an exosome-based diagnostic and research tool for molecular screening of human cancers. PMID:24722878

  13. Making the invisible visible: a microfluidic chip using a low refractive index polymer.

    PubMed

    Hanada, Yasutaka; Ogawa, Tatsuya; Koike, Kazuhiko; Sugioka, Koji

    2016-07-01

    Microfluidic frameworks known as micro-total-analysis-systems or lab-on-a-chip have become versatile tools in cell biology research, since functional biochips are able to streamline dynamic observations of various cells. Glass or polymers are generally used as the substrate due to their high transparency, chemical stability and cost-effectiveness. However, these materials are not well suited for the microscopic observation of cell migration at the fluid boundary due to the refractive index mismatch between the medium and the biochip material. For this reason, we have developed a new method of fabricating three-dimensional (3D) microfluidic chips made of the low refractive index fluoric polymer CYTOP. This novel fabrication procedure involves the use of a femtosecond laser for direct writing, followed by wet etching with a dilute fluorinated solvent and annealing, to create high-quality 3D microfluidic chips inside a polymer substrate. A microfluidic chip made in this manner enabled us to more clearly observe the flagellum motion of a Dinoflagellate moving in circles near the fluid surface compared to the observations possible using conventional microfluidic chips. We believe that CYTOP microfluidic chips made using this new method may allow more detailed analysis of various cell migrations near solid boundaries. PMID:27265196

  14. A Rapidly Fabricated Microfluidic Chip for Cell Culture.

    PubMed

    Li, Rui; Lv, Xuefei; Hasan, Murtaza; Xu, Jiandong; Xu, Yuanqing; Zhang, Xingjian; Qin, Kuiwei; Wang, Jianshe; Zhou, Di; Deng, Yulin

    2016-04-01

    Microfluidic chips (μFC) are emerging as powerful tools in chemistry, biochemistry, nanotechnology and biotechnology. The microscale size, possibility of integration and high-throughput present huge technical potential to facilitate the research of cell behavior by creating in vivo-like microenvironments. Here, we have developed a new method for rapid fabrication of μFC with Norland Optical Adhesive 81 (NOA81) for multiple cell culture with high efficiency. The proposed method is more suitable for the early structure exploration stage of μFC than existing procedures since no templates are needed and fast fabrication methods are presented. Simple PDMS-NOA81-linked microvalves were embedded in the μFC to control or block the fluid flow effectively, which significantly broadened the applications of μFC. Various types of cells were integrated into the chip and normal viabilities were maintained up to 1 week. Besides, concentration gradient was generated to investigate the cells in the μFC responded to drug stimulation. The cells appeared different in terms of shape and proliferation that strongly demonstrated the potential application of our μFC in online drug delivery. The high biocompatibility of NOA81 and its facile fabrication (μFC) promise its use in various cell analyses, such as cell-cell interactions or tissue engineering. PMID:26657733

  15. Studies on spectroscopy of glycerol in THz range using microfluidic chip-integrated micropump

    NASA Astrophysics Data System (ADS)

    Su, Bo; Han, Xue; Wu, Ying; Zhang, Cunlin

    2014-11-01

    Terahertz time-domain spectroscopy (THz-TDS) is a detection method of biological molecules with label-free, non-ionizing, non-intrusive, no pollution and real-time monitoring. But owing to the strong THz absorption by water, it is mainly used in the solid state detection of biological molecules. In this paper, we present a microfluidic chip technique for detecting biological liquid samples using the transmission type of THz-TDS system. The microfluidic channel of the microfluidic chip is fabricated in the quartz glass using Micro-Electro-Mechanical System (MEMS) technology and sealed with polydimethylsiloxane (PDMS) diaphragm. The length, width and depth of the microfluidic channel are 25mm, 100μm and 50μm, respectively. The diameter of THz detection zone in the microfluidic channel is 4mm. The thicknesses of quartz glass and PDMS diaphragm are 1mm and 250μm, individually. Another one of the same quartz glass is used to bond with the PDMS for the rigidity and air tightness of the microfluidic chip. In order to realize the automation of sampling and improve the control precise of fluid, a micropump, which comprises PDMS diaphragm, pump chamber, diffuser and nozzle and flat vibration motor, is integrated on the microfluidic chip. The diffuser and nozzle are fabricated on both sides of the pump chamber, which is covered with PDMS diaphragm. The flat vibration motor is stuck on the PDMS diaphragm as the actuator. We study the terahertz absorption spectroscopy characteristics of glycerol with the concentration of 98% in the microfluidic chip by the aid of the THz-TDS system, and the feasibility of the microfluidic chip for the detection of liquid samples is proved.

  16. Microfluidic device (ExoChip) for On-Chip isolation, quantification and characterization of circulating exosomes

    PubMed Central

    Kanwar, Shailender Singh; Dunlay, Christopher James; Simeone, Diane M.; Nagrath, Sunitha

    2014-01-01

    Membrane bound vesicles, including microvesicles and exosomes, are secreted by both normal and cancerous cells into the extracellular space and in blood circulation. These circulating extracellular vesicles (cirEVs) and exosomes in particular are recognized as a potential source of disease biomarkers. However, to exploit the use of circulatory exosomes as a biomarker, a rapid, high-throughput and reproducible method is required for their isolation and molecular analysis. We have developed a simple, low cost microfluidic-based platform to isolate cirEVs enriched in exosomes directly from blood serum allowing simultaneous capture and quantification of exosomes in a single device. To capture specific exosomes, we employed “ExoChip”, a microfluidic device fabricated in polydimethylsiloxane (PDMS) and functionalized with antibodies against CD63, an antigen commonly overexpressed in exosomes. Subsequent staining with a fluorescent carbocyanine dye (DiO) that specifically labels the exosomes, we quantitated exosomes using a standard plate-reader. Ten independent ExoChip experiments performed using serum obtained from five pancreatic cancer patients and five healthy individuals revealed a statistically significant increase (2.34±0.31 fold, p <0.001) in exosomes captured in cancer patients when compared to healthy individuals. Exosomal origins of ExoChip immobilized vesicles were further confirmed using immuno-electron-microscopy and Western blotting. In addition, we demonstrate the ability of ExoChip to recover exosomes with intact RNA enabling profiling of exosomal-microRNAs through openarray analysis, which has potential applications in biomarker discovery. Based on our findings, ExoChip is a well suited platform to be used as an exosome-based diagnostic and research tool for molecular screening of human cancers. PMID:24722878

  17. PDMS based microfluidic chips and their application in material synthesis

    NASA Astrophysics Data System (ADS)

    Gong, Xiuqing

    reactions. Here, we report the microfluidic fabrication of magnetically responsive microsphere, macroporous polymer microspheres and hollow titania microspheres. To prepare magnetically responsive microsphere, we introduced magnetic particles into liquid shell and drug into liquid core. After cross-linking reaction of the shell, we studied the magnetic contraction and extention behavior which induced the drug release efficiency. To prepare porous polymer, the H 2O2 solution was encapsulated in polymer precursor, after which we investigated its decomposition under UV irradiation, which simultaneously induces the polymerization of the encapsulating shell. Because the H 2O2 decomposition leads to the release of oxygen, porous microspheres were obtained from a combined H2O2-decomposition/polymer precursor polymerization reaction. To prepare hollow titanium gel microspheres, water droplets were first formed by the flow focusing geometry in microfluidic chip and used as a soft template. Then hydrolysis and gelation of titanium alkoxide on the droplet's surface were induced in following serpentine channels, controlled by interface water diffusion. The water diffusion process can be controlled by the amount of the "dewetting" reagent butanol, by which the surface morphology of the titania microspheres can be tuned.

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

    PubMed Central

    2011-01-01

    Microfluidics has become an important tool in diagnosing many diseases, including neurological and genetic disorders. Alzheimer's disease (AD) is a neurodegenerative disease that irreversibly and progressively destroys memory, language ability, and thinking skills. Commonly, detection of AD is expensive and complex. Fluorescence in situ hybridization (FISH)-based microfluidic chip platform is capable of diagnosing AD at an early stage and they are effective tools for the diagnosis with low cost, high speed, and high sensitivity. In this review, we tried to provide basic information on the diagnosis of AD via FISH-based microfluidics. Different sample preparations using a microfluidic chip for diagnosis of AD are highlighted. Moreover, rapid innovations in nanotechnology for diagnosis are explained. This review will provide information on dynamic quantification methods for the diagnosis and treatment of AD. The knowledge provided in this review will help develop new integration diagnostic techniques based on FISH and microfluidics. PMID:21619660

  19. Microfluidic chips for the study of cell migration under the effect of chemicals

    NASA Astrophysics Data System (ADS)

    Kukhtevich, I. V.; Belousov, K. I.; Bukatin, A. S.; Chubinskiy-Nadezhdin, V. I.; Vasileva, V. Yu.; Negulyaev, Yu. A.; Evstrapov, A. A.

    2016-05-01

    Numerical simulation of the formation of a chemoattractant gradient in reaction chambers of a chip having different geometries enabled the determination of a structure suitable for the study of cell migration, in accordance with which hybrid polymer-glass microfluidic devices were manufactured. Verification of the procedures of alignment of cells in the reaction chamber of the chip by centrifugal force and subsequent culturing of the cells showed that microfluidic chips can be used to study cell migration under the effect of the chemoattractant gradient in vitro.

  20. Cooperative Suction by Vertical Capillary Array Pump for Controlling Flow Profiles of Microfluidic Sensor Chips

    PubMed Central

    Horiuchi, Tsutomu; Hayashi, Katsuyoshi; Seyama, Michiko; Inoue, Suzuyo; Tamechika, Emi

    2012-01-01

    A passive pump consisting of integrated vertical capillaries has been developed for a microfluidic chip as an useful component with an excellent flow volume and flow rate. A fluidic chip built into a passive pump was used by connecting the bottoms of all the capillaries to a top surface consisting of a thin layer channel in the microfluidic chip where the thin layer channel depth was smaller than the capillary radius. As a result the vertical capillaries drew fluid cooperatively rather than independently, thus exerting the maximum suction efficiency at every instance. This meant that a flow rate was realized that exhibited little variation and without any external power or operation. A microfluidic chip built into this passive pump had the ability to achieve a quasi-steady rather than a rapidly decreasing flow rate, which is a universal flow characteristic in an ordinary capillary. PMID:23202035

  1. On-chip microfluidic biosensor using superparamagnetic microparticles

    PubMed Central

    Kokkinis, G.; Keplinger, F.; Giouroudi, I.

    2013-01-01

    In this paper, an integrated solution towards an on-chip microfluidic biosensor using the magnetically induced motion of functionalized superparamagnetic microparticles (SMPs) is presented. The concept of the proposed method is that the induced velocity on SMPs in suspension, while imposed to a magnetic field gradient, is inversely proportional to their volume. Specifically, a velocity variation of suspended functionalized SMPs inside a detection microchannel with respect to a reference velocity, specified in a parallel reference microchannel, indicates an increase in their non-magnetic volume. This volumetric increase of the SMPs is caused by the binding of organic compounds (e.g., biomolecules) to their functionalized surface. The new compounds with the increased non-magnetic volume are called loaded SMPs (LSMPs). The magnetic force required for the manipulation of the SMPs and LSMPs is produced by current currying conducting microstructures, driven by a programmable microcontroller. Experiments were carried out as a proof of concept. A promising decrease in the velocity of the LSMPs in comparison to that of the SMPs was measured. Thus, it is the velocity variation which determines the presence of the organic compounds in the sample fluid. PMID:24396528

  2. Microfluidic lab-on-a-chip platforms: requirements, characteristics and applications.

    PubMed

    Mark, Daniel; Haeberle, Stefan; Roth, Günter; von Stetten, Felix; Zengerle, Roland

    2010-03-01

    This critical review summarizes developments in microfluidic platforms that enable the miniaturization, integration, automation and parallelization of (bio-)chemical assays (see S. Haeberle and R. Zengerle, Lab Chip, 2007, 7, 1094-1110, for an earlier review). In contrast to isolated application-specific solutions, a microfluidic platform provides a set of fluidic unit operations, which are designed for easy combination within a well-defined fabrication technology. This allows the easy, fast, and cost-efficient implementation of different application-specific (bio-)chemical processes. In our review we focus on recent developments from the last decade (2000s). We start with a brief introduction into technical advances, major market segments and promising applications. We continue with a detailed characterization of different microfluidic platforms, comprising a short definition, the functional principle, microfluidic unit operations, application examples as well as strengths and limitations of every platform. The microfluidic platforms in focus are lateral flow tests, linear actuated devices, pressure driven laminar flow, microfluidic large scale integration, segmented flow microfluidics, centrifugal microfluidics, electrokinetics, electrowetting, surface acoustic waves, and dedicated systems for massively parallel analysis. This review concludes with the attempt to provide a selection scheme for microfluidic platforms which is based on their characteristics according to key requirements of different applications and market segments. Applied selection criteria comprise portability, costs of instrument and disposability, sample throughput, number of parameters per sample, reagent consumption, precision, diversity of microfluidic unit operations and the flexibility in programming different liquid handling protocols (295 references). PMID:20179830

  3. Rapid prototyping of microfluidic chips for dead-volume-free MS coupling.

    PubMed

    Dietze, Claudia; Scholl, Tobias; Ohla, Stefan; Appun, Johannes; Schneider, Christoph; Belder, Detlev

    2015-11-01

    A fast and straightforward method to prototype microfluidic chip systems for dead-volume-free hyphenation to electrospray-ionisation mass spectrometry is presented. The developed approach based on liquid-phase lithography provides an inexpensive and reliable access to microfluidic chips for MS coupling which can be manufactured in any laboratory with low technical demands. The rapid prototyping approach enables the seamless integration of capillaries serving as electrospray emitters with negligible dead volume. The high versatility of the presented prototyping method and the applicability of a variety of chip-based devices in different fields of lab-on-a-chip technology are established for analytical separations by means of chip-electrochromatography-MS and for continuous-flow synthesis using microreactor technology with MS detection. PMID:26391402

  4. IFSA: a microfluidic chip-platform for frit-based immunoassay protocols

    NASA Astrophysics Data System (ADS)

    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.

  5. Rapid fabrication of microfluidic chips based on the simplest LED lithography

    NASA Astrophysics Data System (ADS)

    Li, Yue; Wu, Ping; Luo, Zhaofeng; Ren, Yuxuan; Liao, Meixiang; Feng, Lili; Li, Yuting; He, Liqun

    2015-05-01

    Microfluidic chips are generally fabricated by a soft lithography method employing commercial lithography equipment. These heavy machines require a critical room environment and high lamp power, and the cost remains too high for most normal laboratories. Here we present a novel microfluidics fabrication method utilizing a portable ultraviolet (UV) LED as an alternative UV source for photolithography. With this approach, we can repeat several common microchannels as do these conventional commercial exposure machines, and both the verticality of the channel sidewall and lithography resolution are proved to be acceptable. Further microfluidics applications such as mixing, blood typing and microdroplet generation are implemented to validate the practicability of the chips. This simple but innovative method decreases the cost and requirement of chip fabrication dramatically and may be more popular with ordinary laboratories.

  6. Chip-olate’ and dry-film resists for efficient fabrication, singulation and sealing of microfluidic chips

    NASA Astrophysics Data System (ADS)

    Temiz, Yuksel; Delamarche, Emmanuel

    2014-09-01

    This paper describes a technique for high-throughput fabrication and efficient singulation of chips having closed microfluidic structures and takes advantage of dry-film resists (DFRs) for efficient sealing of capillary systems. The technique is illustrated using 4-inch Si/SiO2 wafers. Wafers carrying open microfluidic structures are partially diced to about half of their thickness. Treatments such as surface cleaning are done at wafer-level, then the structures are sealed using low-temperature (45 °C) lamination of a DFR that is pre-patterned using a craft cutter, and ready-to-use chips are finally separated manually like a chocolate bar by applying a small force (≤ 4 N). We further show that some DFRs have low auto-fluorescence at wavelengths typically used for common fluorescent dyes and that mechanical properties of some DFRs allow for the lamination of 200 μm wide microfluidic structures with negligible sagging (~1 μm). The hydrophilicity (advancing contact angle of ~60°) of the DFR supports autonomous capillary-driven flow without the need for additional surface treatment of the microfluidic chips. Flow rates from 1 to 5 µL min-1 are generated using different geometries of channels and capillary pumps. In addition, the ‘chip-olate’ technique is compatible with the patterning of capture antibodies on DFR for use in immunoassays. We believe this technique to be applicable to the fabrication of a wide range of microfluidic and lab-on-a-chip devices and to offer a viable alternative to many labor-intensive processes that are currently based on wafer bonding techniques or on the molding of poly(dimethylsiloxane) (PDMS) layers.

  7. Active pneumatic control of centrifugal microfluidic flows for lab-on-a-chip applications.

    PubMed

    Clime, Liviu; Brassard, Daniel; Geissler, Matthias; Veres, Teodor

    2015-06-01

    This paper reports a novel method of controlling liquid motion on a centrifugal microfluidic platform based on the integration of a regulated pressure pump and a programmable electromechanical valving system. We demonstrate accurate control over the displacement of liquids within the system by pressurizing simultaneously multiple ports of the microfluidic device while the platform is rotating at high speed. Compared to classical centrifugal microfluidic platforms where liquids are solely driven by centrifugal and capillary forces, the method presented herein adds a new degree of freedom for fluidic manipulation, which represents a paradigm change in centrifugal microfluidics. We first demonstrate how various core microfluidic functions such as valving, switching, and reverse pumping (i.e., against the centrifugal field) can be easily achieved by programming the pressures applied at dedicated access ports of the microfluidic device. We then show, for the first time, that the combination of centrifugal force and active pneumatic pumping offers the possibility of mixing fluids rapidly (~0.1 s) and efficiently based on the creation of air bubbles at the bottom of a microfluidic reservoir. Finally, the suitability of the developed platform for performing complex bioanalytical assays in an automated fashion is demonstrated in a DNA harvesting experiment where recovery rates of about 70% were systematically achieved. The proposed concept offers the interesting prospect to decouple basic microfluidic functions from specific material properties, channel dimensions and fabrication tolerances, surface treatments, or on-chip active components, thus promoting integration of complex assays on simple and low-cost microfluidic cartridges. PMID:25860103

  8. 3D-printed microfluidic chips with patterned, cell-laden hydrogel constructs.

    PubMed

    Knowlton, Stephanie; Yu, Chu Hsiang; Ersoy, Fulya; Emadi, Sharareh; Khademhosseini, Ali; Tasoglu, Savas

    2016-06-01

    Three-dimensional (3D) printing offers potential to fabricate high-throughput and low-cost fabrication of microfluidic devices as a promising alternative to traditional techniques which enables efficient design iterations in the development stage. In this study, we demonstrate a single-step fabrication of a 3D transparent microfluidic chip using two alternative techniques: a stereolithography-based desktop 3D printer and a two-step fabrication using an industrial 3D printer based on polyjet technology. This method, compared to conventional fabrication using relatively expensive materials and labor-intensive processes, presents a low-cost, rapid prototyping technique to print functional 3D microfluidic chips. We enhance the capabilities of 3D-printed microfluidic devices by coupling 3D cell encapsulation and spatial patterning within photocrosslinkable gelatin methacryloyl (GelMA). The platform presented here serves as a 3D culture environment for long-term cell culture and growth. Furthermore, we have demonstrated the ability to print complex 3D microfluidic channels to create predictable and controllable fluid flow regimes. Here, we demonstrate the novel use of 3D-printed microfluidic chips as controllable 3D cell culture environments, advancing the applicability of 3D printing to engineering physiological systems for future applications in bioengineering. PMID:27321481

  9. An Anti-Adhesion Technique in Microfluidic Channel Using Dielectrophoresis for Particle Processing Microfluidic Chip Applications.

    PubMed

    Kang, Dong-Hyun; Kim, Min-Gu; Seo, Hye-Kyoung; Kim, Yong-Jun

    2015-09-01

    Particle adhesion to the walls of microfluidic channels is a prominent cause of deteriorating performance and reliability in miniaturized analytical devices; it can also cause unexpected changes in their structures and operating conditions. Therefore, the demand of anti-adhesion for wall loss reduction on particle processing chips is high. This paper demonstrates an anti-adhesion technique using dielectrophoresis. The proposed technique is applied to a distribution microchannel for a feasibility test and is then applied to a blood plasma filter, which is a human blood cell and plasma separation device. In the distribution microchannel, the application of electric potentials of 0-20 V(pp) at 3 MHz caused the wall loss of polystyrene latex (PSL) particles to decrease with decreasing particle diameter. When an electric potential of 20 V(pp) was applied in a distribution microchannel experiment using PSL particles, the wall loss decreased by 52.7 ± 3% for 10-μm-diameter particles. On the other hand, when a 20 V(pp) electric potential was applied in a distribution microchannel experiment using human blood cells, the wall loss decreased by 66.4 ± 6%. In the blood plasma filter, the wall loss decreased by 54.89 ± 5% at 20 V(pp) and 1 MHz. The purity efficiency of the blood plasma filter was 69.56% without the wall loss reduction technique and 95.14% when the applied electric potential was 20 V(pp). PMID:26485924

  10. Microfluidic-integrated laser-controlled microactuators with on-chip microscopy imaging functionality

    PubMed Central

    Jung, Jae Hee; Han, Chao; Lee, Seung Ah; Kim, Jinho; Yang, Changhuei

    2014-01-01

    The fabrication of a novel microfluidic system, integrated with a set of laser-controlled microactuators on an ePetri on-chip microscopy platform, is presented in this paper. In the fully integrated microfluidic system, a set of novel thermally actuated paraffin-based microactuators, precisely controlled by programmed laser optics, was developed to regulate flow and to provide pumping of liquid solutions without external connections. The microfluidic chip was fabricated on a complementary metal–oxide–semiconductor (CMOS)-imaging sensor chip on an ePetri platform; this configuration provided real-time, wide field-of-view, high-resolution imaging using a sub-pixel sweeping microscopy technique. The system of microactuators, which consisted of microvalves and a micropump, operated well in the microfluidic channel with a focused near-infrared laser beam providing the actuation control. As a demonstration, we used our prototype to assess cell–drug interactions, and monitored cell growth directly within an incubator in real time. The powerful combination of the laser-actuated microfluidics and chip-scale microscopy techniques represents a significant step forward in terms of a simple, robust, high-throughput, and highly compact analysis system for biomedical and bioscience applications. PMID:25099225

  11. Microfluidic-integrated laser-controlled microactuators with on-chip microscopy imaging functionality.

    PubMed

    Jung, Jae Hee; Han, Chao; Lee, Seung Ah; Kim, Jinho; Yang, Changhuei

    2014-10-01

    The fabrication of a novel microfluidic system, integrated with a set of laser-controlled microactuators on an ePetri on-chip microscopy platform, is presented in this paper. In the fully integrated microfluidic system, a set of novel thermally actuated paraffin-based microactuators, precisely controlled by programmed laser optics, was developed to regulate flow and to provide pumping of liquid solutions without external connections. The microfluidic chip was fabricated on a complementary metal-oxide-semiconductor (CMOS)-imaging sensor chip on an ePetri platform; this configuration provided real-time, wide field-of-view, high-resolution imaging using a sub-pixel sweeping microscopy technique. The system of microactuators, which consisted of microvalves and a micropump, operated well in the microfluidic channel with a focused near-infrared laser beam providing the actuation control. As a demonstration, we used our prototype to assess cell-drug interactions and to monitor cell growth directly within an incubator in real time. The powerful combination of laser-actuated microfluidics and chip-scale microscopy techniques represents a significant step forward in terms of a simple, robust, high-throughput, and highly compact analysis system for biomedical and bioscience applications. PMID:25099225

  12. Recent progress in preparation and application of microfluidic chip electrophoresis

    NASA Astrophysics Data System (ADS)

    Cong, Hailin; Xu, Xiaodan; Yu, Bing; Yuan, Hua; Peng, Qiaohong; Tian, Chao

    2015-05-01

    Since its discovery in 1990, microfluidic chip electrophoresis (MCE) has allowed the development of applications with small size, fast analysis, low cost, high integration density and automatic level, which are easy to carry and have made commercialization efficient. MCE has been widely used in the areas of environmental protection, biochemistry, medicine and health, clinical testing, judicial expertise, food sanitation, pharmaceutical checking, drug testing, agrochemistry, biomedical engineering and life science. As one of the foremost fields in the research of capillary electrophoresis, MCE is the ultimate frontier to develop the miniaturized, integrated, automated all-in-one instruments needed in modern analytical chemistry. By adopting the advanced technologies of micro-machining, lasers and microelectronics, and the latest research achievements in analytical chemistry and biochemistry, the sampling, separation and detection systems of commonly used capillary electrophoresis are integrated with high densities onto glass, quartz, silicon or polymer wafers to form the MCE, which can finish the analysis of multi-step operations such as injection, enrichment, reaction, derivatization, separation, and collection of samples in a portable, efficient and super high speed manner. With reference to the different technological achievements in this area, the latest developments in MCE are reviewed in this article. The preparation mechanisms, surface modifications, and properties of different materials in MCE are compared, and the different sampling, separation and detection systems in MCE are summarized. The performance of MCE in analysis of fluorescent substance, metallic ion, sugar, medicine, nucleic acid, DNA, amino acid, polypeptide and protein is discussed, and the future direction of development is forecast.

  13. Fabrication of dielectrophoretic microfluidic chips using a facile screen-printing technique for microparticle trapping

    NASA Astrophysics Data System (ADS)

    Wee, Wei Hong; Li, Zedong; Hu, Jie; Adib Kadri, Nahrizul; Xu, Feng; Li, Fei; Pingguan-Murphy, Belinda

    2015-10-01

    Trapping of microparticles finds wide applications in numerous fields. Microfluidic chips based on a dielectrophoresis (DEP) technique hold several advantages for trapping microparticles, such as fast result processing, a small amount of sample required, high spatial resolution, and high accuracy of target selection. There is an unmet need to develop DEP microfluidic chips on different substrates for different applications in a low cost, facile, and rapid way. This study develops a new facile method based on a screen-printing technique for fabrication of electrodes of DEP chips on three types of substrates (i.e. polymethyl-methacrylate (PMMA), poly(ethylene terephthalate) and A4 paper). The fabricated PMMA-based DEP microfluidic chip was selected as an example and successfully used to trap and align polystyrene microparticles in a suspension and cardiac fibroblasts in a cell culture solution. The developed electrode fabrication method is compatible with different kinds of DEP substrates, which could expand the future application field of DEP microfluidic chips, including new forms of point-of care diagnostics and trapping circulating tumor cells.

  14. Manually Operatable On-Chip Bistable Pneumatic Microstructures for Microfluidic Manipulations

    PubMed Central

    Chen, A.; Pan, T.

    2014-01-01

    Bistable microvalves are of particular interest because of their distinct nature requiring energy consumption only during the transition between the open and closed states. This characteristic can be highly advantageous in reducing the number of external inputs and the complexity of control circuitries for microfluidic devices as contemporary lab-on-a-chip platforms are transferring from research settings to low-resource environments with high integratability and small form factor. In this paper, we first present manually operatable, on-chip bistable pneumatic microstructures (BPM) for microfluidic manipulation. The structural design and operation of the BPM devices can be readily integrated into any pneumatically powered microfluidic network consisting of pneumatic and fluidic channels. It is mainly comprised of a vacuum activation chamber (VAC) and a pressure release chamber (PRC), which users have direct control through finger pressing to switch between bistable vacuum state (VS) or atmospheric state (AS). We have integrated multiple BPM devices into a 4-to-1 microfluidic multiplexor to demonstrate on-chip digital flow switching from different sources. Furthermore, we have shown its clinical relevance in a point-of-care diagnostic chip that process blood samples to identify the distinct blood types (A/B/O) on chip. PMID:25007840

  15. Droplet-on-a-wristband: chip-to-chip digital microfluidic interfaces between replaceable and flexible electrowetting modules.

    PubMed

    Fan, Shih-Kang; Yang, Hanping; Hsu, Wensyang

    2011-01-21

    We present a long (204 mm), curved (curvature of 0.04 mm(-1)), and closed droplet pathway in "droplet-on-a-wristband" (DOW) with the designed digital microfluidic modular interfaces for electric signal and droplet connections based on the study of electrowetting-on-dielectric (EWOD) in inclined and curved devices. Instead of using sealed and leakage-proof pipes to transmit liquid and pumping pressure, the demonstrated modular interface for electrowetting-driven digital microfluidics provides simply electric and fluidic connections between two adjacent parallel-plate modules which are easy-to-attach/detach, showing the advantages of using droplets for microfluidic connections between modules. With the previously reported digital-to-channel interfaces (Abdelgawad et al., Lab Chip, 2009, 9, 1046-1051), the chip-to-chip interface presented here would be further applied to continuous microfluidics. Droplet pumping across a single top plate gap and through a modular interface with two gaps between overlapping plates are investigated. To ensure the droplet transportation in the DOW, we actuate droplets against gravity in an inclined or curved device fabricated on flexible PET substrates prepared by a special razor blade cutter and low temperature processes. Pumping a 2.5 μl droplet at a speed above 105 mm s(-1) is achieved by sequentially switching the entire 136 driving electrodes (1.5 mm × 1.5 mm) along the four flexible modules of the DOW fabricated by 4-inch wafer facilities. PMID:20957291

  16. Ex Situ Integration of Multifunctional Porous Polymer Monoliths into Thermoplastic Microfluidic Chips

    PubMed Central

    Kendall, Eric L.; Wienhold, Erik; Rahmanian, Omid D.; DeVoe, Don L.

    2014-01-01

    A unique method for incorporating functional porous polymer monolith elements into thermoplastic microfluidic chips is described. Monolith elements are formed in a microfabricated mold, rather than within the microchannels, and chemically functionalized off chip before insertion into solvent-softened thermoplastic microchannels during chip assembly. Because monoliths may be trimmed prior to final placement, control of their size, shape, and uniformity is greatly improved over in-situ photopolymerization methods. A characteristic trapezoidal profile facilitates rapid insertion and enables complete mechanical anchoring of the monolith periphery, eliminating the need for chemical attachment to the microchannel walls. Off-chip processing allows the parallel preparation of monoliths of differing compositions and surface chemistries in large batches. Multifunctional flow-through arrays of multiple monolith elements are demonstrated using this approach through the creation of a fluorescent immunosensor with integrated controls, and a microfluidic bubble separator comprising a combination of integrated hydrophobic and hydrophilic monolith elements. PMID:25018587

  17. Microfluidic LC Device with Orthogonal Sample Extraction for On-Chip MALDI-MS Detection

    PubMed Central

    Lazar, Iulia M.; Kabulski, Jarod L.

    2013-01-01

    A microfluidic device that enables on-chip matrix assisted laser desorption ionization-mass spectrometry (MALDI-MS) detection for liquid chromatography (LC) separations is described. The device comprises an array of functional elements to carry out LC separations, integrates a novel microchip-MS interface to facilitate the orthogonal transposition of the microfluidic LC channel into an array of reservoirs, and enables sensitive MALDI-MS detection directly from the chip. Essentially, the device provides a snapshot MALDI-MS map of the content of the separation channel present on the chip. The detection of proteins with biomarker potential from MCF10A breast epithelial cell extracts, and detection limits in the low fmol range, are demonstrated. In addition, the design of the novel LC-MALDI-MS chip entices the promotion of a new concept for performing sample separations within the limited time-frame that accompanies the dead-volume of a separation channel. PMID:23592150

  18. Inkjet 3D printing of microfluidic structures—on the selection of the printer towards printing your own microfluidic chips

    NASA Astrophysics Data System (ADS)

    Walczak, Rafał; Adamski, Krzysztof

    2015-08-01

    This article reports, for the first time, the results of detailed research on the application of inkjet 3D printing for the fabrication of microfluidic structures. CAD designed test structures were printed with four different printers. Dimensional fidelity, shape conformity, and surface roughness were studied for each printout. It was found that the minimum dimension (width or depth) for a properly printed microfluidic channel was approximately 200 μm. Although the nominal resolution of the printers was one order of magnitude better, smaller structures were significantly deformed or not printed at all. It was also found that a crucial step in one-step fabrication of embedded microchannels is the removal of the support material. We also discuss the source of print error and present a way to evaluate other printers. The printouts obtained from the four different printers were compared, and the optimal printing technique and printer were used to fabricate a microfluidic structure for the spectrophotometric characterisation of beverages. UV/VIS absorbance characteristics were collected using this microfluidic structure, demonstrating that the fabricated spectrophotometric chip operated properly. Thus, a proof-of-concept for using inkjet 3D printing for the fabrication of microfluidic structures was obtained.

  19. PPC750 Performance Monitor

    NASA Technical Reports Server (NTRS)

    Meyer, Donald; Uchenik, Igor

    2007-01-01

    The PPC750 Performance Monitor (Perfmon) is a computer program that helps the user to assess the performance characteristics of application programs running under the Wind River VxWorks real-time operating system on a PPC750 computer. Perfmon generates a user-friendly interface and collects performance data by use of performance registers provided by the PPC750 architecture. It processes and presents run-time statistics on a per-task basis over a repeating time interval (typically, several seconds or minutes) specified by the user. When the Perfmon software module is loaded with the user s software modules, it is available for use through Perfmon commands, without any modification of the user s code and at negligible performance penalty. Per-task run-time performance data made available by Perfmon include percentage time, number of instructions executed per unit time, dispatch ratio, stack high water mark, and level-1 instruction and data cache miss rates. The performance data are written to a file specified by the user or to the serial port of the computer

  20. A novel mast cell co-culture microfluidic chip for the electrochemical evaluation of food allergen.

    PubMed

    Jiang, Hui; Jiang, Donglei; Zhu, Pei; Pi, Fuwei; Ji, Jian; Sun, Chao; Sun, Jiadi; Sun, Xiulan

    2016-09-15

    In this study a novel cell-to-cell electrochemical microfluidic chip was developed for qualitative and quantitative analysis of food allergen. Microfluidic cell culture, food allergen-induced cell morphological changes, and cell metabolism measurements were performed simultaneously using the aforementioned device. RBL-2H3 mast cells and ANA-1 macrophages have been used within a cell co-culture model to observe their allergic response when they are introduced to the antigen stimulus. Two cell cultivation microfluidic channels are located in the microfluidic chip, which is fabricated with four groups of gold electrodes, with an additional "capillary". In order to detect the allergic response, the cells were stimulated with dinitrophenylated bovine serum albumin (DNP-BSA) without anti-DNP IgE incubation. When exocytosis occurs, the cell-secreted inflammatory cytokines were measured by enzyme-linked immuno sorbent assay (ELISA) and cell impedance changes were detected using cell-based electrochemical assay. Results indicate that the real-time cell allergic response are accurately monitored by this electrochemical microfluidic chip, which provides a general example of rapidly prototyped low-cost biosensor technology for applications in both food allergen detection and investigation. PMID:27108255

  1. Fuel cell-powered microfluidic platform for lab-on-a-chip applications.

    PubMed

    Esquivel, Juan Pablo; Castellarnau, Marc; Senn, Tobias; Löchel, Bernd; Samitier, Josep; Sabaté, Neus

    2012-01-01

    The achievement of a higher degree of integration of components--especially micropumps and power sources--is a challenge currently being pursued to obtain portable and totally autonomous microfluidic devices. This paper presents the integration of a micro direct methanol fuel cell (μDMFC) in a microfluidic platform as a smart solution to provide both electrical and pumping power to a Lab-on-a-Chip system. In this system the electric power produced by the fuel cell is available to enable most of the functionalites required by the microfluidic chip, while the generated CO(2) from the electrochemical reaction produces a pressure capable of pumping a liquid volume through a microchannel. The control of the fuel cell operating conditions allows regulation of the flow rate of a liquid sample through a microfluidic network. The relation between sample flow rate and the current generated by the fuel cell is practically linear, achieving values in the range of 4-18 μL min(-1) while having an available power between 1-4 mW. This permits adjusting the desired flow rate for a given application by controlling the fuel cell output conditions and foresees a fully autonomous analytical Lab-on-a-Chip in which the same device would provide the electrical power to a detection module and at the same time use the CO(2) pumping action to flow the required analytes through a particular microfluidic design. PMID:22072241

  2. Cocaine detection by a mid-infrared waveguide integrated with a microfluidic chip.

    PubMed

    Chang, Yu-Chi; Wägli, Philip; Paeder, Vincent; Homsy, Alexandra; Hvozdara, Lubos; van der Wal, Peter; Di Francesco, Joab; de Rooij, Nico F; Peter Herzig, Hans

    2012-09-01

    A germanium (Ge) strip waveguide on a silicon (Si) substrate is integrated with a microfluidic chip to detect cocaine in tetrachloroethylene (PCE) solutions. In the evanescent field of the waveguide, cocaine absorbs the light near 5.8 μm, which is emitted from a quantum cascade laser. This device is ideal for (bio-)chemical sensing applications. PMID:22806146

  3. A microfluidic chip using phenol formaldehyde resin for uniform-sized polycaprolactone and chitosan microparticle generation.

    PubMed

    Lin, Yung-Sheng; Yang, Chih-Hui; Wu, Chin-Tung; Grumezescu, Alexandru Mihai; Wang, Chih-Yu; Hsieh, Wan-Chen; Chen, Szu-Yu; Huang, Keng-Shiang

    2013-01-01

    This study develops a new solvent-compatible microfluidic chip based on phenol formaldehyde resin (PFR). In addition to its solvent-resistant characteristics, this microfluidic platform also features easy fabrication, organization, decomposition for cleaning, and reusability compared with conventional chips. Both solvent-dependent (e.g., polycaprolactone) and nonsolvent-dependent (e.g., chitosan) microparticles were successfully prepared. The size of emulsion droplets could be easily adjusted by tuning the flow rates of the dispersed/continuous phases. After evaporation, polycaprolactone microparticles ranging from 29.3 to 62.7 μm and chitosan microparticles ranging from 215.5 to 566.3 μm were obtained with a 10% relative standard deviation in size. The proposed PFR microfluidic platform has the advantages of active control of the particle size with a narrow size distribution as well as a simple and low cost process with a high throughput. PMID:23736788

  4. Science Issues Associated with the Use of a Microfluidic Chip Designed Specifically for Protein Crystallization

    NASA Technical Reports Server (NTRS)

    Holmes, Anna M.; Monaco, Lisa; Barnes, Cindy; Spearing, Scott; Jenkins, Andy; Johnson, Todd; Mayer, Derek; Cole, Helen

    2003-01-01

    The Iterative Biological Crystallization team in partnership with Caliper Technologies has produced a prototype microfluidic chip for batch crystallization that has been designed and tested. The chip is designed for the mixing and dispensing of up to five solutions with possible variation of the recipe being delivered to two growth wells. Developments that have led to the successful on-chip crystallization of a few model proteins have required investigative insight into many different areas, including fluid mixing dynamics, surface treatments, quantification and fidelity of reagent delivery. This presentation will encompass the ongoing studies and data accumulated toward these efforts.

  5. A PDMS-Based Microfluidic Hanging Drop Chip for Embryoid Body Formation.

    PubMed

    Wu, Huei-Wen; Hsiao, Yi-Hsing; Chen, Chih-Chen; Yet, Shaw-Fang; Hsu, Chia-Hsien

    2016-01-01

    The conventional hanging drop technique is the most widely used method for embryoid body (EB) formation. However, this method is labor intensive and limited by the difficulty in exchanging the medium. Here, we report a microfluidic chip-based approach for high-throughput formation of EBs. The device consists of microfluidic channels with 6 × 12 opening wells in PDMS supported by a glass substrate. The PDMS channels were fabricated by replicating polydimethyl-siloxane (PDMS) from SU-8 mold. The droplet formation in the chip was tested with different hydrostatic pressures to obtain optimal operation pressures for the wells with 1000 μm diameter openings. The droplets formed at the opening wells were used to culture mouse embryonic stem cells which could subsequently developed into EBs in the hanging droplets. This device also allows for medium exchange of the hanging droplets making it possible to perform immunochemistry staining and characterize EBs on chip. PMID:27399655

  6. PPC user's manual

    SciTech Connect

    Brown, S.A.; Barrett, K.A.; Braddy, D.

    1993-01-04

    The Portable Process Control library (PPC) is a set of routines to execute and communicate with other processes in environments which permit such operations. The goal is to establish an easy to use interface which can be implemented on a wide variety of platforms. The standard C library I/O interface was taken as a model. In this view, processes are treated as much like files as is possible. In particular, a process is opened and closed as is a file and that means that it is forked by the parent to start with and killed at the end. While a process is open it may be written to and read from with PPC functions which are analogous to the standard C I/O functions fprintf and fgets. In addition, there are functions to monitor the status of the child processes. These do not have precise analogs to file routines, but since the basic interface has been established by the open/close and read/write routines, these have obvious usages.

  7. Quantum Dot-Bead-DNA Probe-Based Hybridization Fluorescence Assays on Microfluidic Chips.

    PubMed

    Ankireddy, Seshadri Reddy; Kim, Jongsung

    2015-10-01

    The development of chip-based, quantum dot (QD)-bead-DNA conjugate probes for hybridization detection is a prime research focus in the field of microfluidics. QD-Bead-DNA probe-based hybridization detection methods are often called "bead-based assays," and their success is substantially influenced by the dispensing and manipulation capabilities of microfluidic technology. Met was identified as a prognostic marker in different cancers including lung, renal, liver, head and neck, stomach, and breast. In this report, the cancer causing Met gene was detected with QDs attached to polystyrene microbeads. We constructed a microfluidic platform using a flexible PDMS polymer. The chip consists of two channels, with two inlets and two outlets. The two channels were integrated with QD-bead-DNA probes for simultaneous detection of wild type target DNA and mutant DNA, containing three nucleotide changes compared to the wild type sequence. The fluorescence quenching ability of QDs within the channels of microfluidic chips were compared for both DNAs. PMID:26726440

  8. Peroxynitrous-acid-induced chemiluminescence detection of nitrite based on Microfluidic chip.

    PubMed

    Wu, Jing; Wang, Xiong; Lin, Yitong; Zheng, Yongzan; Lin, Jin-Ming

    2016-07-01

    A chemiluminescent method for nitrite detection was developed on microfluidic chip. Carbon dots-NaNO2(-) acidified H2O2 system was adopted. Chemiluminescence (CL) spectrum of this system was detected. The radiative recombination of hole-injected and electron-injected carbon dots explained their CL property. Spiral microchannels were designed on the microfluidic chip to allow enough reaction time for the carbon dots-NaNO2-acidified H2O2 system. Carbon dots and NaNO2 were premixed in the branch microchannel, then, the mixture reacted with acidified H2O2 in spiral microchannels. Concentrations of H2SO4 and H2O2, dilution ratio of carbon dots in H2O and flow rate were optimized to obtain the best CL signals. The approach presented satisfactory linear relationship between NaNO2 concentration and CL intensity. The tolerance of metal ions in determination of 1×10(-5)M nitrite was analyzed. The nitrites in water and beverage samples were successfully analyzed on the microfluidic chip with good repeatability. The data were well accordance with the results obtained from GB 5009.33(-) 2010. This microfluidic CL detection method is believed to be a simple, automatic and agent-save approach for inorganic ion analysis. PMID:27154650

  9. Digital Microfluidic Dynamic Culture of Mammalian Embryos on an Electrowetting on Dielectric (EWOD) Chip.

    PubMed

    Huang, Hong-Yuan; Shen, Hsien-Hua; Tien, Chang-Hung; Li, Chin-Jung; Fan, Shih-Kang; Liu, Cheng-Hsien; Hsu, Wen-Syang; Yao, Da-Jeng

    2015-01-01

    Current human fertilization in vitro (IVF) bypasses the female oviduct and manually inseminates, fertilizes and cultivates embryos in a static microdrop containing appropriate chemical compounds. A microfluidic microchannel system for IVF is considered to provide an improved in-vivo-mimicking environment to enhance the development in a culture system for an embryo before implantation. We demonstrate a novel digitalized microfluidic device powered with electrowetting on a dielectric (EWOD) to culture an embryo in vitro in a single droplet in a microfluidic environment to mimic the environment in vivo for development of the embryo and to culture the embryos with good development and live births. Our results show that the dynamic culture powered with EWOD can manipulate a single droplet containing one mouse embryo and culture to the blastocyst stage. The rate of embryo cleavage to a hatching blastocyst with a dynamic culture is significantly greater than that with a traditional static culture (p<0.05). The EWOD chip enhances the culture of mouse embryos in a dynamic environment. To test the reproductive outcome of the embryos collected from an EWOD chip as a culture system, we transferred embryos to pseudo-pregnant female mice and produced live births. These results demonstrate that an EWOD-based microfluidic device is capable of culturing mammalian embryos in a microfluidic biological manner, presaging future clinical application. PMID:25933003

  10. Digital Microfluidic Dynamic Culture of Mammalian Embryos on an Electrowetting on Dielectric (EWOD) Chip

    PubMed Central

    Huang, Hong-Yuan; Shen, Hsien-Hua; Tien, Chang-Hung; Li, Chin-Jung; Fan, Shih-Kang; Liu, Cheng-Hsien; Hsu, Wen-Syang; Yao, Da-Jeng

    2015-01-01

    Current human fertilization in vitro (IVF) bypasses the female oviduct and manually inseminates, fertilizes and cultivates embryos in a static microdrop containing appropriate chemical compounds. A microfluidic microchannel system for IVF is considered to provide an improved in-vivo-mimicking environment to enhance the development in a culture system for an embryo before implantation. We demonstrate a novel digitalized microfluidic device powered with electrowetting on a dielectric (EWOD) to culture an embryo in vitro in a single droplet in a microfluidic environment to mimic the environment in vivo for development of the embryo and to culture the embryos with good development and live births. Our results show that the dynamic culture powered with EWOD can manipulate a single droplet containing one mouse embryo and culture to the blastocyst stage. The rate of embryo cleavage to a hatching blastocyst with a dynamic culture is significantly greater than that with a traditional static culture (p<0.05). The EWOD chip enhances the culture of mouse embryos in a dynamic environment. To test the reproductive outcome of the embryos collected from an EWOD chip as a culture system, we transferred embryos to pseudo-pregnant female mice and produced live births. These results demonstrate that an EWOD-based microfluidic device is capable of culturing mammalian embryos in a microfluidic biological manner, presaging future clinical application. PMID:25933003

  11. Microfluidic chip-based technologies: emerging platforms for cancer diagnosis

    PubMed Central

    2013-01-01

    The development of early and personalized diagnostic protocols is considered the most promising avenue to decrease mortality from cancer and improve outcome. The emerging microfluidic-based analyzing platforms hold high promises to fulfill high-throughput and high-precision screening with reduced equipment cost and low analysis time, as compared to traditional bulky counterparts in bench-top laboratories. This article overviewed the potential applications of microfluidic technologies for detection and monitoring of cancer through nucleic acid and protein biomarker analysis. The implications of the technologies in cancer cytology that can provide functional personalized diagnosis were highlighted. Finally, the future niches for using microfluidic-based systems in tumor screening were briefly discussed. PMID:24070124

  12. Two-stage microfluidic chip for selective isolation of circulating tumor cells (CTCs).

    PubMed

    Hyun, Kyung-A; Lee, Tae Yoon; Lee, Su Hyun; Jung, Hyo-Il

    2015-05-15

    Over the past few decades, circulating tumor cells (CTCs) have been studied as a means of overcoming cancer. However, the rarity and heterogeneity of CTCs have been the most significant hurdles in CTC research. Many techniques for CTC isolation have been developed and can be classified into positive enrichment (i.e., specifically isolating target cells using cell size, surface protein expression, and so on) and negative enrichment (i.e., specifically eluting non-target cells). Positive enrichment methods lead to high purity, but could be biased by their selection criteria, while the negative enrichment methods have relatively low purity, but can isolate heterogeneous CTCs. To compensate for the known disadvantages of the positive and negative enrichments, in this study we introduced a two-stage microfluidic chip. The first stage involves a microfluidic magnetic activated cell sorting (μ-MACS) chip to elute white blood cells (WBCs). The second stage involves a geometrically activated surface interaction (GASI) chip for the selective isolation of CTCs. We observed up to 763-fold enrichment in cancer cells spiked into 5 mL of blood sample using the μ-MACS chip at 400 μL/min flow rate. Cancer cells were successfully separated with separation efficiencies ranging from 10.19% to 22.91% based on their EpCAM or HER2 surface protein expression using the GASI chip at a 100 μL/min flow rate. Our two-stage microfluidic chips not only isolated CTCs from blood cells, but also classified heterogeneous CTCs based on their characteristics. Therefore, our chips can contribute to research on CTC heterogeneity of CTCs, and, by extension, personalized cancer treatment. PMID:25060749

  13. Capillary-driven microfluidic chips with evaporation-induced flow control and dielectrophoretic microbead trapping

    NASA Astrophysics Data System (ADS)

    Temiz, Yuksel; Skorucak, Jelena; Delamarche, Emmanuel

    2014-07-01

    This work reports our efforts on developing simple-to-use microfluidic devices for point-of-care diagnostic applications with recent extensions that include the trapping of microbeads using dielectrophoresis (DEP) and the modulation of the liquid flow using integrated microheaters. DEP serves the purpose of trapping microbeads coated with receptors and analytes for detection of a fluorescent signal. The microheater is actuated once the chip is filled by capillarity, creating an evaporation-induced flow tuned according to assay conditions. The chips are composed of a glass substrate patterned with 50-nm-thick Pd electrodes and microfluidic structures made using a 20-μm-thick dry-film resist (DFR). Chips are covered/sealed by low temperature (50°C) lamination of a 50-μm-thick DFR layer having excellent optical and mechanical properties. To separate cleaned and sealed chips from the wafer, we used an effective chip singulation technique which we informally call the "chip-olate" process. In the experimental section, we first studied dielectrophoretic trapping of 10-μm beads for flow rates ranging from 80 pL s-1 to 2.5 nL s-1 that are generated by an external syringe pump. Then, we characterized the embedded microheater in DFR-covered chips. Flow rates as high as 8 nL s-1 were generated by evaporation-induced flow when the heater was biased by 10 V, corresponding to 270-mW power. Finally, DEP-based trapping and fluorescent detection of functionalized beads were demonstrated as the flow was generated by evaporation-induced flow after the microfluidic structures were filled by capillarity.

  14. Acoustic micro-vortexing of fluids, particles and cells in disposable microfluidic chips.

    PubMed

    Iranmanesh, Ida; Ohlin, Mathias; Ramachandraiah, Harisha; Ye, Simon; Russom, Aman; Wiklund, Martin

    2016-08-01

    We demonstrate an acoustic platform for micro-vortexing in disposable polymer microfluidic chips with small-volume (20 μl) reaction chambers. The described method is demonstrated for a variety of standard vortexing functions, including mixing of fluids, re-suspension of a pellet of magnetic beads collected by a magnet placed on the chip, and lysis of cells for DNA extraction. The device is based on a modified Langevin-type ultrasonic transducer with an exponential horn for efficient coupling into the microfluidic chip, which is actuated by a low-cost fixed-frequency electronic driver board. The transducer is optimized by numerical modelling, and different demonstrated vortexing functions are realized by actuating the transducer for varying times; from fractions of a second for fluid mixing, to half a minute for cell lysis and DNA extraction. The platform can be operated during 1 min below physiological temperatures with the help of a PC fan, a Peltier element and an aluminum heat sink acting as the chip holder. As a proof of principle for sample preparation applications, we demonstrate on-chip cell lysis and DNA extraction within 25 s. The method is of interest for automating and chip-integrating sample preparation procedures in various biological assays. PMID:27444649

  15. Parallel-plate lab-on-a-chip based on digital microfluidics for on-chip electrochemical analysis

    NASA Astrophysics Data System (ADS)

    Yu, Yuhua; Chen, Jianfeng; Zhou, Jia

    2014-01-01

    This paper describes an electrowetting on dielectric (EWOD) digital microfluidic-based lab-on-a-chip (LOC) integrated with on-chip electrochemical microsensor by IC compatible fabrication process, and its application for the entire online biosensing process capable of fully automatic analysis for ferrocenemethanol (FcM) and dopamine (DA). In this work, we made full use of the parallel-plate structure of the EWOD digital microfluidic device to fabricate the microfluidic module on the bottom plate and the three-microelectrode-system-integrated electrochemical cell together with patterned ground electrode on the top plate. The proposed LOC possesses the multifunction of: (1) creating, merging and transporting of microliter-level sample droplets, (2) online biosensing, and (3) droplets recycling. The three-electrode-integrated microsensor not only reveals a sensitive electrochemical detection for FcM in a wide concentration range (10 µM-1.0 mM), but also shows good stability, selectivity and reproducibility for surface-controlled detection of DA. The calibration of DA was linear for concentration from 1.0 to 50.0 µM with a high sensitivity of 2145 nA µM-1 cm-2 (R2 = 0.9933) and estimated detection limit of 0.42 µM (signal/noise ratio of 3). This work shows the promise of state-of-the-art digital microfluidic biosensors for fully automatic online bioanalysis in a future LOC to perform on-chip biomedical protocols in vitro diagnostic assays.

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

    PubMed Central

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

    2016-01-01

    An optical fiber sensor integrated microfluidic chip is presented for ultrasensitive detection of glucose. A long-period grating (LPG) inscribed in a small-diameter single-mode fiber (SDSMF) is employed as an optical refractive-index (RI) sensor. With the layer-by-layer (LbL) self-assembly technique, poly (ethylenimine) (PEI) and poly (acrylic acid) (PAA) multilayer film is deposited on the SDSMF-LPG sensor for both supporting and signal enhancement, and then a glucose oxidase (GOD) layer is immobilized on the outer layer for glucose sensing. A microfluidic chip for glucose detection is fabricated after embedding the SDSMF-LPG biosensor into the microchannel of the chip. Experimental results reveal that the SDSMF-LPG biosensor based on such a hybrid sensing film can ultrasensitively detect glucose concentration as low as 1 nM. After integration into the microfluidic chip, the detection range of the sensor is extended from 2 µM to 10 µM, and the response time is remarkablely shortened from 6 minutes to 70 seconds. PMID:27231643

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

    PubMed

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

    2016-05-01

    An optical fiber sensor integrated microfluidic chip is presented for ultrasensitive detection of glucose. A long-period grating (LPG) inscribed in a small-diameter single-mode fiber (SDSMF) is employed as an optical refractive-index (RI) sensor. With the layer-by-layer (LbL) self-assembly technique, poly (ethylenimine) (PEI) and poly (acrylic acid) (PAA) multilayer film is deposited on the SDSMF-LPG sensor for both supporting and signal enhancement, and then a glucose oxidase (GOD) layer is immobilized on the outer layer for glucose sensing. A microfluidic chip for glucose detection is fabricated after embedding the SDSMF-LPG biosensor into the microchannel of the chip. Experimental results reveal that the SDSMF-LPG biosensor based on such a hybrid sensing film can ultrasensitively detect glucose concentration as low as 1 nM. After integration into the microfluidic chip, the detection range of the sensor is extended from 2 µM to 10 µM, and the response time is remarkablely shortened from 6 minutes to 70 seconds. PMID:27231643

  18. Microfluidic organ-on-chip technology for blood-brain barrier research

    PubMed Central

    van der Helm, Marinke W; van der Meer, Andries D; Eijkel, Jan C T; van den Berg, Albert; Segerink, Loes I

    2016-01-01

    ABSTRACT Organs-on-chips are a new class of microengineered laboratory models that combine several of the advantages of current in vivo and in vitro models. In this review, we summarize the advances that have been made in the development of organ-on-chip models of the blood-brain barrier (BBBs-on-chips) and the challenges that are still ahead. The BBB is formed by specialized e3ndothelial cells and separates blood from brain tissue. It protects the brain from harmful compounds from the blood and provides homeostasis for optimal neuronal function. Studying BBB function and dysfunction is important for drug development and biomedical research. Microfluidic BBBs-on-chips enable real-time study of (human) cells in an engineered physiological microenvironment, for example incorporating small geometries and fluid flow as well as sensors. Examples of BBBs-on-chips in literature already show the potential of more realistic microenvironments and the study of organ-level functions. A key challenge in the field of BBB-on-chip development is the current lack of standardized quantification of parameters such as barrier permeability and shear stress. This limits the potential for direct comparison of the performance of different BBB-on-chip models to each other and existing models. We give recommendations for further standardization in model characterization and conclude that the rapidly emerging field of BBB-on-chip models holds great promise for further studies in BBB biology and drug development. PMID:27141422

  19. Interfacial tension based on-chip extraction of microparticles confined in microfluidic Stokes flows

    NASA Astrophysics Data System (ADS)

    Huang, Haishui; He, Xiaoming

    2014-10-01

    Microfluidics involving two immiscible fluids (oil and water) has been increasingly used to produce hydrogel microparticles with wide applications. However, it is difficult to extract the microparticles out of the microfluidic Stokes flows of oil that have a Reynolds number (the ratio of inertia to viscous force) much less than one, where the dominant viscous force tends to drive the microparticles to move together with the surrounding oil. Here, we present a passive method for extracting hydrogel microparticles in microfluidic Stokes flow from oil into aqueous extracting solution on-chip by utilizing the intrinsic interfacial tension between oil and the microparticles. We further reveal that the thickness of an "extended confining layer" of oil next to the interface between oil and aqueous extracting solution must be smaller than the radius of microparticles for effective extraction. This method uses a simple planar merging microchannel design that can be readily fabricated and further integrated into a fluidic system to extract microparticles for wide applications.

  20. Optical hyperpolarization and NMR detection of 129Xe on a microfluidic chip

    NASA Astrophysics Data System (ADS)

    Jiménez-Martínez, Ricardo; Kennedy, Daniel J.; Rosenbluh, Michael; Donley, Elizabeth A.; Knappe, Svenja; Seltzer, Scott J.; Ring, Hattie L.; Bajaj, Vikram S.; Kitching, John

    2014-05-01

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

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

    PubMed

    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. PMID:27089377

  2. Single-use thermoplastic microfluidic burst valves enabling on-chip reagent storage

    PubMed Central

    Rahmanian, Omid D.

    2014-01-01

    A simple and reliable method for fabricating single-use normally closed burst valves in thermoplastic microfluidic devices is presented, using a process flow that is readily integrated into established workflows for the fabrication of thermoplastic microfluidics. An experimental study of valve performance reveals the relationships between valve geometry and burst pressure. The technology is demonstrated in a device employing multiple valves engineered to actuate at different inlet pressures that can be generated using integrated screw pumps. On-chip storage and reconstitution of fluorescein salt sealed within defined reagent chambers are demonstrated. By taking advantage of the low gas and water permeability of cyclic olefin copolymer, the robust burst valves allow on-chip hermetic storage of reagents, making the technology well suited for the development of integrated and disposable assays for use at the point of care. PMID:25972774

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

    PubMed Central

    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. PMID:27089377

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

    PubMed

    Perestrelo, Ana Rubina; Águas, Ana C P; Rainer, Alberto; Forte, Giancarlo

    2015-01-01

    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. PMID:26690442

  5. Design and fabrication of a microfluidic chip driven by dielectric elastomers

    NASA Astrophysics Data System (ADS)

    Li, Bo; Chen, Hualing; Wu, Jiuhui; Zhu, Zicai; Xia, Dongmei; Jing, Sufang

    2009-07-01

    This paper presents a valveless microfluidic chip driven by dielectric elastomers (DEs). First, the planar DE actuator is designed and the diaphragm actuating performances were characterized. Then the micro chip, containing a pump chamber and a pair of nozzle/diffuser, is fabricated on SU-8 under exposure to UV-light with a mask. The diaphragm and the SU-8 is sealed and finally covered by a PMMA. The pumping and flow rate is tested and measured under high AC supply, and a maxim flow rate of 21.2μl is achieved under 3500V, 8Hz sine wave.

  6. Dual-wavelength fluorescent detection of particles on a novel microfluidic chip.

    PubMed

    Jiang, Hai; Weng, Xuan; Li, Dongqing

    2013-03-01

    This paper reports a novel lab-on-a-chip device that performs fluorescent particle counting by coupling the electrokinetically-induced pressure-driven flow and a miniaturized dual-wavelength fluorescent detection method. A novel L-shaped PDMS microchannel bonded on a thin glass slide is used to transport the particles. The dual-wavelength fluorescent detection system can count two different fluorescent particles simultaneously. Good agreement is achieved between the results obtained by the microfluidic chip device and the results from a commercial flow cytometer. PMID:23291857

  7. Electrotaxis Studies of Lung Cancer Cells using a Multichannel Dual-electric-field Microfluidic Chip.

    PubMed

    Hou, Hsien-San; Chang, Hui-Fang; Cheng, Ji-Yen

    2015-01-01

    The behavior of directional cell migration under a direct current electric-field (dcEF) is referred to as electrotaxis. The significant role of physiological dcEF in guiding cell movement during embryo development, cell differentiation, and wound healing has been demonstrated in many studies. By applying microfluidic chips to an electrotaxis assay, the investigation process is shortened and experimental errors are minimized. In recent years, microfluidic devices made of polymeric substances (e.g., polymethylmethacrylate, PMMA, or acrylic) or polydimethylsiloxane (PDMS) have been widely used in studying the responses of cells to electrical stimulation. However, unlike the numerous steps required to fabricate a PDMS device, the simple and rapid construction of the acrylic microfluidic chip makes it suitable for both device prototyping and production. Yet none of the reported devices facilitate the efficient study of the simultaneous chemical and dcEF effects on cells. In this report, we describe our design and fabrication of an acrylic-based multichannel dual-electric-field (MDF) chip to investigate the concurrent effect of chemical and electrical stimulation on lung cancer cells. The MDF chip provides eight combinations of electrical/chemical stimulations in a single test. The chip not only greatly shortens the required experimental time but also increases accuracy in electrotaxis studies. PMID:26780080

  8. Parallel temperature-dependent microrheological measurements in a microfluidic chip.

    PubMed

    Josephson, Lilian Lam; Galush, William J; Furst, Eric M

    2016-07-01

    Microfluidic stickers are used as a sample environment to measure the microrheology of monoclonal antibody (mAb) protein solutions. A Peltier-based microscope stage is implemented and validated, and is capable of controlling the sample temperature over the range 0.9-40 °C. The design accounts for heat transfer to and from the objective, controls the sample environment humidity to mitigate condensation, and provides adequate damping to reduce vibration from the cooling system. A concentrated sucrose solution is used as a standard sample to provide an in situ temperature measurement by the Stokes-Einstein-Sutherland relation. By combining microfluidic stickers and microrheology, 72 temperature-concentration viscosity measurements of mAb solutions can be made in 1 day, a significant increase in throughput over conventional rheometry. PMID:27375825

  9. Integrated optofluidic-microfluidic twin channels: toward diverse application of lab-on-a-chip systems

    NASA Astrophysics Data System (ADS)

    Lv, Chao; Xia, Hong; Guan, Wei; Sun, Yun-Lu; Tian, Zhen-Nan; Jiang, Tong; Wang, Ying-Shuai; Zhang, Yong-Lai; Chen, Qi-Dai; Ariga, Katsuhiko; Yu, Yu-De; Sun, Hong-Bo

    2016-01-01

    Optofluidics, which integrates microfluidics and micro-optical components, is crucial for optical sensing, fluorescence analysis, and cell detection. However, the realization of an integrated system from optofluidic manipulation and a microfluidic channel is often hampered by the lack of a universal substrate for achieving monolithic integration. In this study, we report on an integrated optofluidic-microfluidic twin channels chip fabricated by one-time exposure photolithography, in which the twin microchannels on both surfaces of the substrate were exactly aligned in the vertical direction. The twin microchannels can be controlled independently, meaning that fluids could flow through both microchannels simultaneously without interfering with each other. As representative examples, a tunable hydrogel microlens was integrated into the optofluidic channel by femtosecond laser direct writing, which responds to the salt solution concentration and could be used to detect the microstructure at different depths. The integration of such optofluidic and microfluidic channels provides an opportunity to apply optofluidic detection practically and may lead to great promise for the integration and miniaturization of Lab-on-a-Chip systems.

  10. Integrated optofluidic-microfluidic twin channels: toward diverse application of lab-on-a-chip systems

    PubMed Central

    Lv, Chao; Xia, Hong; Guan, Wei; Sun, Yun-Lu; Tian, Zhen-Nan; Jiang, Tong; Wang, Ying-Shuai; Zhang, Yong-Lai; Chen, Qi-Dai; Ariga, Katsuhiko; Yu, Yu-De; Sun, Hong-Bo

    2016-01-01

    Optofluidics, which integrates microfluidics and micro-optical components, is crucial for optical sensing, fluorescence analysis, and cell detection. However, the realization of an integrated system from optofluidic manipulation and a microfluidic channel is often hampered by the lack of a universal substrate for achieving monolithic integration. In this study, we report on an integrated optofluidic-microfluidic twin channels chip fabricated by one-time exposure photolithography, in which the twin microchannels on both surfaces of the substrate were exactly aligned in the vertical direction. The twin microchannels can be controlled independently, meaning that fluids could flow through both microchannels simultaneously without interfering with each other. As representative examples, a tunable hydrogel microlens was integrated into the optofluidic channel by femtosecond laser direct writing, which responds to the salt solution concentration and could be used to detect the microstructure at different depths. The integration of such optofluidic and microfluidic channels provides an opportunity to apply optofluidic detection practically and may lead to great promise for the integration and miniaturization of Lab-on-a-Chip systems. PMID:26823292

  11. Integrated optofluidic-microfluidic twin channels: toward diverse application of lab-on-a-chip systems.

    PubMed

    Lv, Chao; Xia, Hong; Guan, Wei; Sun, Yun-Lu; Tian, Zhen-Nan; Jiang, Tong; Wang, Ying-Shuai; Zhang, Yong-Lai; Chen, Qi-Dai; Ariga, Katsuhiko; Yu, Yu-De; Sun, Hong-Bo

    2016-01-01

    Optofluidics, which integrates microfluidics and micro-optical components, is crucial for optical sensing, fluorescence analysis, and cell detection. However, the realization of an integrated system from optofluidic manipulation and a microfluidic channel is often hampered by the lack of a universal substrate for achieving monolithic integration. In this study, we report on an integrated optofluidic-microfluidic twin channels chip fabricated by one-time exposure photolithography, in which the twin microchannels on both surfaces of the substrate were exactly aligned in the vertical direction. The twin microchannels can be controlled independently, meaning that fluids could flow through both microchannels simultaneously without interfering with each other. As representative examples, a tunable hydrogel microlens was integrated into the optofluidic channel by femtosecond laser direct writing, which responds to the salt solution concentration and could be used to detect the microstructure at different depths. The integration of such optofluidic and microfluidic channels provides an opportunity to apply optofluidic detection practically and may lead to great promise for the integration and miniaturization of Lab-on-a-Chip systems. PMID:26823292

  12. Continuous isolation of monocytes using a magnetophoretic-based microfluidic Chip.

    PubMed

    Darabi, Jeff; Guo, Chuan

    2016-10-01

    Monocytes play an important role in the immune system and are responsible for phagocytizing and degrading foreign microorganisms in the body. The isolation of monocytes is important in various immunological applications such as in-vitro culture of dendritic cells. We present a magnetophoretic-based microfluidic chip for rapid isolation of highly purified, untouched monocytes from human blood by a negative selection method. This bioseparation platform integrates several unique features into a microfluidic device, including locally engineered magnetic field gradients and a continuous flow with a buffer switching scheme to improve the performance of the cell separation process. The results indicate high monocyte purity and recovery performances at a volumetric flow rate that is nearly an order of magnitude larger than comparable microfluidic devices reported in literature. In addition, a comprehensive 2-D computational modeling is performed to determine the cell trajectory and trapping length within the microfluidic chip. Furthermore, the effects of channel height, substrate thickness, cell size, number of beads per cell, and sample flow rate on the cell separation performance are studied. PMID:27518600

  13. Fabrication of Poly(methyl Methacrylate) microfluidic chips by redox-initiated polymerization

    SciTech Connect

    Chen, Jiang; Lin, Yuehe; Chen, Gang

    2007-08-16

    In this report, a method based on the redox-initiated polymerization of methyl methacrylate (MMA) has been developed for the rapid fabrication of PMMA microfluidic chips.The new fabrication approach obviates the need for special equipment and significantly simplifies the process of fabricating microdevices. The attractive performance of the novel PMMA microchips has been demonstrated in connection with contactless conductivity detection for the separation and detection of ionic species.

  14. Design of liquid lens based optical system for microfluidic chip detection

    NASA Astrophysics Data System (ADS)

    Niu, Lijun; Zhou, Ya; Hu, Xiaoming; Zhou, Chang

    2015-08-01

    The precision of manufacturing and installing together with the flexibility is a serious challenge for laser induced fluorescent detector (LIFD) of microfluidic chip. In this paper, a focus tunable liquid lens based on liquid zoom system for LIFD with automatic adjustment is proposed. With the help of liquid zoom lens whose surface curvature can be varied continuously by current, the system can achieve a continuous zoom. Instead of using the traditional mechanical axial displacement scanning motion mechanism, the proposed zoom system can implement axial displacement scan by means of the well-designed autofocus feedback current control function. The simulation results show that the focal length variation range of the designed optical system is 4.87mm~ 8.40mm, which is also the axial scanning displacement range. The size of scanning spot is around 15μm when a 473nm wavelength laser is used, which can meet the demand of microfluidic chip detection. With this design, the required precision of the LIFD could be reduced significantly as well as costs. Moreover, it also makes the detection of microfluidic chip qualified to adapt to different size of detecting channel.

  15. A review of digital microfluidics as portable platforms for lab-on a-chip applications.

    PubMed

    Samiei, Ehsan; Tabrizian, Maryam; Hoorfar, Mina

    2016-07-01

    Following the development of microfluidic systems, there has been a high tendency towards developing lab-on-a-chip devices for biochemical applications. A great deal of effort has been devoted to improve and advance these devices with the goal of performing complete sets of biochemical assays on the device and possibly developing portable platforms for point of care applications. Among the different microfluidic systems used for such a purpose, digital microfluidics (DMF) shows high flexibility and capability of performing multiplex and parallel biochemical operations, and hence, has been considered as a suitable candidate for lab-on-a-chip applications. In this review, we discuss the most recent advances in the DMF platforms, and evaluate the feasibility of developing multifunctional packages for performing complete sets of processes of biochemical assays, particularly for point-of-care applications. The progress in the development of DMF systems is reviewed from eight different aspects, including device fabrication, basic fluidic operations, automation, manipulation of biological samples, advanced operations, detection, biological applications, and finally, packaging and portability of the DMF devices. Success in developing the lab-on-a-chip DMF devices will be concluded based on the advances achieved in each of these aspects. PMID:27272540

  16. Capillary-driven surface-enhanced Raman scattering (SERS)-based microfluidic chip for abrin detection

    PubMed Central

    2014-01-01

    Herein, we firstly demonstrate the design and the proof-of-concept use of a capillary-driven surface-enhanced Raman scattering (SERS)-based microfluidic chip for abrin detection. The micropillar array substrate was etched and coated with a gold film by microelectromechanical systems (MEMS) process to integrate into a lateral flow test strip. The detection of abrin solutions of various concentrations was performed by the as-prepared microfluidic chip. It was shown that the correlation between the abrin concentration and SERS signal was found to be linear within the range of 0.1 ng/mL to 1 μg/mL with a limit of detection of 0.1 ng/mL. Our microfluidic chip design enhanced the operability of SERS-based immunodiagnostic techniques, significantly reducing the complication and cost of preparation as compared to previous SERS-based works. Meanwhile, this design proved the superiority to conventional lateral flow test strips in respect of both sensitivity and quantitation and showed great potential in the diagnosis and treatment for abrin poisoning as well as on-site screening of abrin-spiked materials. PMID:24655483

  17. Capillary-driven surface-enhanced Raman scattering (SERS)-based microfluidic chip for abrin detection.

    PubMed

    Yang, Hao; Deng, Min; Ga, Shan; Chen, Shouhui; Kang, Lin; Wang, Junhong; Xin, Wenwen; Zhang, Tao; You, Zherong; An, Yuan; Wang, Jinglin; Cui, Daxiang

    2014-01-01

    Herein, we firstly demonstrate the design and the proof-of-concept use of a capillary-driven surface-enhanced Raman scattering (SERS)-based microfluidic chip for abrin detection. The micropillar array substrate was etched and coated with a gold film by microelectromechanical systems (MEMS) process to integrate into a lateral flow test strip. The detection of abrin solutions of various concentrations was performed by the as-prepared microfluidic chip. It was shown that the correlation between the abrin concentration and SERS signal was found to be linear within the range of 0.1 ng/mL to 1 μg/mL with a limit of detection of 0.1 ng/mL. Our microfluidic chip design enhanced the operability of SERS-based immunodiagnostic techniques, significantly reducing the complication and cost of preparation as compared to previous SERS-based works. Meanwhile, this design proved the superiority to conventional lateral flow test strips in respect of both sensitivity and quantitation and showed great potential in the diagnosis and treatment for abrin poisoning as well as on-site screening of abrin-spiked materials. PMID:24655483

  18. A disposable microfluidic biochip with on-chip molecularly imprinted biosensors for optical detection of anesthetic propofol.

    PubMed

    Hong, Chien-Chong; Chang, Po-Hsiang; Lin, Chih-Chung; Hong, Chian-Lang

    2010-05-15

    This paper presents a disposable microfluidic biochip with on-chip molecularly imprinted biosensors for optical detection of anesthetic propofol. So far, the methods to detect anesthetic propofol in hospitals are liquid chromatography (LC), high-performance liquid chromatography (HPLC), and gas chromatography-mass spectroscopy (GC-MS). These conventional instruments are bulky, expensive, and not ease of access. In this work, a novel plastic microfluidic biochip with on-chip anesthetic biosensor has been developed and characterized for rapid detection of anesthetic propofol. The template-molecule imprinted polymers were integrated into microfluidic biochips to be used for detecting anesthetic propofol optically at 655 nm wavelength after the reaction of propofol with color reagent. Experimental results show that the sensitivity of the microfluidic biochip with on-chip molecularly imprinted polymers (MIPs) biosensor is 6.47 mV/(ppm mm(2)). The specific binding of MIP to non-imprinted polymer (NIP) is up to 456%. And the detection limit of the microsystem is 0.25 ppm with a linear detection range from 0.25 to 10 ppm. The disposable microfluidic biochip with on-chip anesthetic biosensor using molecularly imprinted polymers presented in this work showed excellent performance in separation and sensing of anesthetic propofol molecules. While compared to large-scale conventional instruments, the developed microfluidic biochips with on-chip MIP biosensors have the advantages of compact size, high sensitivity, high selectivity, low cost, and fast response. PMID:20206494

  19. Recent Results of the Investigation of a Microfluidic Sampling Chip and Sampling System for Hot Cell Aqueous Processing Streams

    SciTech Connect

    Julia Tripp; Jack Law; Tara Smith

    2013-10-01

    A Fuel Cycle Research and Development project has investigated an innovative sampling method that could evolve into the next generation sampling and analysis system for metallic elements present in aqueous processing streams. Initially sampling technologies were evaluated and microfluidics sampling chip technology was selected and tested. A conceptual design for a fully automated microcapillary-based system was completed and a robotic automated sampling system was fabricated. The mechanical and sampling operation of the completed sampling system was investigated. In addition, the production of a less expensive, mass produced sampling chip was investigated to avoid chip reuse thus increasing sampling reproducibility/accuracy. The microfluidic-based robotic sampling system’s mechanical elements were tested to ensure analytical reproducibility and the optimum robotic handling of microfluidic sampling chips.

  20. Disposable on-chip microfluidic system for buccal cell lysis, DNA purification, and polymerase chain reaction.

    PubMed

    Cho, Woong; Maeng, Joon-Ho; Ahn, Yoomin; Hwang, Seung Yong

    2013-09-01

    This paper reports the development of a disposable, integrated biochip for DNA sample preparation and PCR. The hybrid biochip (25 × 45 mm) is composed of a disposable PDMS layer with a microchannel chamber and reusable glass substrate integrated with a microheater and thermal microsensor. Lysis, purification, and PCR can be performed sequentially on this microfluidic device. Cell lysis is achieved by heat and purification is performed by mechanical filtration. Passive check valves are integrated to enable sample preparation and PCR in a fixed sequence. Reactor temperature is needed to lysis and PCR reaction is controlled within ±1°C by PID controller of LabVIEW software. Buccal epithelial cell lysis, DNA purification, and SY158 gene PCR amplification were successfully performed on this novel chip. Our experiments confirm that the entire process, except the off-chip gel electrophoresis, requires only approximately 1 h for completion. This disposable microfluidic chip for sample preparation and PCR can be easily united with other technologies to realize a fully integrated DNA chip. PMID:23784986

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

    PubMed Central

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

    2014-01-01

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

  2. Temperature regulation during ultrasonic manipulation for long-term cell handling in a microfluidic chip

    NASA Astrophysics Data System (ADS)

    Svennebring, J.; Manneberg, O.; Wiklund, M.

    2007-12-01

    We demonstrate simultaneous micromanipulation and temperature regulation by the use of ultrasonic standing wave technology in a microfluidic chip. The system is based on a microfabricated silicon structure sandwiched between two glass layers, and an external ultrasonic transducer using a refractive wedge placed on top of the chip for efficient coupling of ultrasound into the microchannel. The chip is fully transparent and compatible with any kind of high-resolution optical microscopy. The temperature regulation method uses calibration data of the temperature increase due to the ultrasonic actuation for determining the temperature of the surrounding air and microscope table, controlled by a warm-air heating unit and a heatable mounting frame. The heating methods are independent of each other, resulting in a flexible choice of ultrasonic actuation voltage and flow rate for different cell and particle manipulation purposes. Our results indicate that it is possible to perform stable temperature regulation with an accuracy of the order of ±0.1 °C around any physiologically relevant temperature (e.g., 37 °C) with high temporal stability and repeatability. The purpose is to use ultrasound for long-term cell and/or particle handling in a microfluidic chip while controlling and maintaining the biocompatibility of the system.

  3. Microfluidic chip containing porous gradient for chemotaxis study

    NASA Astrophysics Data System (ADS)

    Al-Abboodi, Aswan; Tjeung, Ricky; Doran, Pauline; Yeo, Leslie; Friend, James; Chan, Peggy

    2011-12-01

    We have developed a new porous gradient microfluidic device based on in situ Gtn-HPA/CMC-Tyr hydrogel that comprises gelatin hydroxyphenylpropionic acid (Gtn-HPA) conjugate and carboxymethyl cellulose tyramine (CMC-Tyr) conjugate. The device is fabricated using a soft lithographic technique, in which microstructures were patterned on a thin layer of polydimethylsiloxane (PDMS) using a polymeric mold. Human fibrosarcoma cells (HT1080) were employed as invasive cancer cell model. Porosity gradients were generated by flowing pore etching fluid in the gradient generator network. Results suggested that spatial control of the porosity can be obtained, which mimics the 3-dimensional microenvironment in vivo for cell-based screening applications including real time chemotaxis, cytotoxicity, and continuous drug-response monitoring. A chemoattractant gradient is then generated and cell migration is monitored in real time using fluorescence microscopy. The viability of cells was evaluated using calcien AM stain. Herein, we successfully monitored the chemotactic responses of cancer cells, confirmed the validity of using in situ porous hydrogels as a construction material for a microchemotaxis device, and demonstrated the potential of the hydrogel with tunable porosity based microfluidic device in biological experiments. This device will also be practical in controlling the chemical and mechanical properties of the surroundings during the formation of tissue engineered constructs.

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

    PubMed

    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

  5. A chitosan coated monolith for nucleic acid capture in a thermoplastic microfluidic chip

    PubMed Central

    Kendall, Eric L.; Wienhold, Erik; DeVoe, Don L.

    2014-01-01

    A technique for microfluidic, pH modulated DNA capture and purification using chitosan functionalized glycidyl methacrylate monoliths is presented. Highly porous polymer monoliths are formed and subsequently functionalized off-chip in a batch process before insertion into thermoplastic microchannels prior to solvent bonding, simplifying the overall fabrication process by eliminating the need for on-chip surface modifications. The monolith anchoring method allows for the use of large cross-section monoliths enabling high flowrates and high DNA capture capacity with a minimum of added design complexity. Using monolith capture elements requiring less than 1 mm2 of chip surface area, loading levels above 100 ng are demonstrated, with DNA capture and elution efficiency of 54.2% ± 14.2% achieved. PMID:25379094

  6. Microfluidic chips for the crystallization of biomacromolecules by counter-diffusion and on-chip crystal X-ray analysis.

    PubMed

    Dhouib, Kaouthar; Khan Malek, Chantal; Pfleging, Wilhelm; Gauthier-Manuel, Bernard; Duffait, Roland; Thuillier, Gaël; Ferrigno, Rosaria; Jacquamet, Lilian; Ohana, Jeremy; Ferrer, Jean-Luc; Théobald-Dietrich, Anne; Giegé, Richard; Lorber, Bernard; Sauter, Claude

    2009-05-21

    Microfluidic devices were designed to perform on micromoles of biological macromolecules and viruses the search and the optimization of crystallization conditions by counter-diffusion, as well as the on-chip analysis of crystals by X-ray diffraction. Chips composed of microchannels were fabricated in poly-dimethylsiloxane (PDMS), poly-methyl-methacrylate (PMMA) and cyclo-olefin-copolymer (COC) by three distinct methods, namely replica casting, laser ablation and hot embossing. The geometry of the channels was chosen to ensure that crystallization occurs in a convection-free environment. The transparency of the materials is compatible with crystal growth monitoring by optical microscopy. The quality of the protein 3D structures derived from on-chip crystal analysis by X-ray diffraction using a synchrotron radiation was used to identify the most appropriate polymers. Altogether the results demonstrate that for a novel biomolecule, all steps from the initial search of crystallization conditions to X-ray diffraction data collection for 3D structure determination can be performed in a single chip. PMID:19417908

  7. Microfluidic chip capillary electrophoresis coupled with electrochemiluminescence for enantioseparation of racemic drugs using central composite design optimization.

    PubMed

    Guo, Wen Peng; Rong, Zhi Bin; Li, Ying Hong; Fung, Ying Sing; Gao, Guo Quan; Cai, Zhi Ming

    2013-11-01

    Optimization based on central composite design (CCD) for enantioseparation of anisodamine (AN), atenolol (AT), and metoprolol (ME) in human urine was developed using a microfluidic chip-CE device. Coupling the flexible and wide working range of microfluidic chip-CE device to CCD for chiral separation of AN, AT, and ME in human urine, a total of 15 experiments is needed for the optimization procedure as compared to 75 experiments using the normal one variable at a time optimization. The optimum conditions obtained are found to be more robust as shown by the curvature effects of the interaction factors. The developed microfluidic chip-CE-ECL system with adjustable dilution ratios has been validated by satisfactory recoveries (89.5-99% for six enanotiomers) in urine sample analysis. The working range (0.3-600 μM), repeatability (3.1-4.9% RSD for peak height and 4.0-5.2% RSD for peak area), and detection limit (0.3-0.6 μM) of the method developed are found to meet the requirements for bedside monitoring of AN, AT, and ME in patients under critical conditions. In summary, the hyphenation of CCD with the microfluidic chip-CE device is shown to offer a rapid means for optimizing the working conditions on simultaneous separation of three racemic drugs using the microfluidic chip-CE device developed. PMID:24037989

  8. Tape underlayment rotary-node (TURN) valves for simple on-chip microfluidic flow control.

    PubMed

    Markov, Dmitry A; Manuel, Steven; Shor, Leslie M; Opalenik, Susan R; Wikswo, John P; Samson, Philip C

    2010-02-01

    We describe a simple and reliable fabrication method for producing multiple, manually activated microfluidic control valves in polydimethylsiloxane (PDMS) devices. These screwdriver-actuated valves reside directly on the microfluidic chip and can provide both simple on/off operation as well as graded control of fluid flow. The fabrication procedure can be easily implemented in any soft lithography lab and requires only two specialized tools-a hot-glue gun and a machined brass mold. To facilitate use in multi-valve fluidic systems, the mold is designed to produce a linear tape that contains a series of plastic rotary nodes with small stainless steel machine screws that form individual valves which can be easily separated for applications when only single valves are required. The tape and its valves are placed on the surface of a partially cured thin PDMS microchannel device while the PDMS is still on the soft-lithographic master, with the master providing alignment marks for the tape. The tape is permanently affixed to the microchannel device by pouring an over-layer of PDMS, to form a full-thickness device with the tape as an enclosed underlayment. The advantages of these Tape Underlayment Rotary-Node (TURN) valves include parallel fabrication of multiple valves, low risk of damaging a microfluidic device during valve installation, high torque, elimination of stripped threads, the capabilities of TURN hydraulic actuators, and facile customization of TURN molds. We have utilized these valves to control microfluidic flow, to control the onset of molecular diffusion, and to manipulate channel connectivity. Practical applications of TURN valves include control of loading and chemokine release in chemotaxis assay devices, flow in microfluidic bioreactors, and channel connectivity in microfluidic devices intended to study competition and predator/prey relationships among microbes. PMID:19859812

  9. Tape underlayment rotary-node (TURN) valves for simple on-chip microfluidic flow control

    PubMed Central

    Markov, Dmitry A.; Manuel, Steven; Shor, Leslie M.; Opalenik, Susan R.; Wikswo, John P.; Samson, Philip C.

    2013-01-01

    We describe a simple and reliable fabrication method for producing multiple, manually activated microfluidic control valves in polydimethylsiloxane (PDMS) devices. These screwdriver-actuated valves reside directly on the microfluidic chip and can provide both simple on/off operation as well as graded control of fluid flow. The fabrication procedure can be easily implemented in any soft lithography lab and requires only two specialized tools – a hot-glue gun and a machined brass mold. To facilitate use in multi-valve fluidic systems, the mold is designed to produce a linear tape that contains a series of plastic rotary nodes with small stainless steel machine screws that form individual valves which can be easily separated for applications when only single valves are required. The tape and its valves are placed on the surface of a partially cured thin PDMS microchannel device while the PDMS is still on the soft-lithographic master, with the master providing alignment marks for the tape. The tape is permanently affixed to the microchannel device by pouring an over-layer of PDMS, to form a full-thickness device with the tape as an enclosed underlayment. The advantages of these Tape Underlayment Rotary-Node (TURN) valves include parallel fabrication of multiple valves, low risk of damaging a microfluidic device during valve installation, high torque, elimination of stripped threads, the capabilities of TURN hydraulic actuators, and facile customization of TURN molds. We have utilized these valves to control microfluidic flow, to control the onset of molecular diffusion, and to manipulate channel connectivity. Practical applications of TURN valves include control of loading and chemokine release in chemotaxis assay devices, flow in microfluidic bioreactors, and channel connectivity in microfluidic devices intended to study competition and predator / prey relationships among microbes. PMID:19859812

  10. Development of multistage distillation in a microfluidic chip.

    PubMed

    Lam, K F; Cao, E; Sorensen, E; Gavriilidis, A

    2011-04-01

    Although there has been a lot of work on the development of microchemical processing systems such as micro-reactors and micro-sensors, little attention has been paid to micro-separation units, and in particular, microscale distillation. In this paper, various silicon-glass microscale distillation chips with different channel configurations were fabricated and tested. A temperature gradient was setup across the chip by heating and cooling the two ends. The feed was located at the middle of the microchannel. Arrays of micropillars were incorporated in order to guide the liquid flow. It was found that the separation performance was promoted by increasing the length of the microchannel. However, this created an imbalance of the liquid flows at the two sides of the microchannel and caused flooding. This hydrodynamic limitation was addressed by incorporating micropillars on both sides of the channel. The most efficient microdistillation chip consisted of a microchannel with 600 microns width and 40 cm length. Experimental results showed high efficiency for the separation of a 50 mol% acetone-water mixture when the heating and cooling temperature were 95 °C and 42 °C respectively. The concentrations of acetone were 3 mol% in the bottom stream and 95 mol% in the distillate, which was equivalent to at least 4 equilibrium stages at total reflux conditions. Furthermore, a 50 mol% methanol-toluene mixture was separated into nearly pure toluene in the bottom stream and 75 mol% methanol in the distillate. The performance of the microdistillation unit was reproducible in repeated tests. PMID:21327250

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

    PubMed

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

    2016-04-01

    In this paper, a colorimetric silver nanoparticles aptasensor (aptamer-AgNPs) was developed for simple and straightforward detection of protein in microfluidic chip. Surface-functionalized microfluidic channels were employed as the capture platform. Then the mixture of target protein and aptamer-AgNPs were injected into the microfluidic channels for colorimetric detection. To demonstrate the performance of this detection platform, thrombin was chosen as a model target protein. Introduction of thrombin could form a sandwich-type complex involving immobilized AgNPs. The amount of aptamer-AgNPs on the complex augmented along with the increase of the thrombin concentration causing different color change that can be analyzed both by naked eyes and a flatbed scanner. This method is featured with low sample consumption, simple processes of microfluidic platform and straightforward colorimetric detection with aptamer-AgNPs. Thrombin at concentrations as low as 20pM can be detected using this aptasensor without signal amplification. This work demonstrated that it had good selectivity over other proteins and it could be a useful strategy to detect other targets with two affinity binding sites for ligands as well. PMID:26838384

  12. Radiolabelling diverse positron emission tomography (PET) tracers using a single digital microfluidic reactor chip.

    PubMed

    Chen, Supin; Javed, Muhammad Rashed; Kim, Hee-Kwon; Lei, Jack; Lazari, Mark; Shah, Gaurav J; van Dam, R Michael; Keng, Pei-Yuin; Kim, Chang-Jin C J

    2014-03-01

    Radiotracer synthesis is an ideal application for microfluidics because only nanogram quantities are needed for positron emission tomography (PET) imaging. Thousands of radiotracers have been developed in research settings but only a few are readily available, severely limiting the biological problems that can be studied in vivo via PET. We report the development of an electrowetting-on-dielectric (EWOD) digital microfluidic chip that can synthesize a variety of (18)F-labeled tracers targeting a range of biological processes by confirming complete syntheses of four radiotracers: a sugar, a DNA nucleoside, a protein labelling compound, and a neurotransmitter. The chip employs concentric multifunctional electrodes that are used for heating, temperature sensing, and EWOD actuation. All of the key synthesis steps for each of the four (18)F-labeled tracers are demonstrated and characterized with the chip: concentration of fluoride ion, solvent exchange, and chemical reactions. The obtained fluorination efficiencies of 90-95% are comparable to, or greater than, those achieved by conventional approaches. PMID:24352530

  13. Euler force actuation mechanism for siphon valving in compact disk-like microfluidic chips.

    PubMed

    Deng, Yongbo; Fan, Jianhua; Zhou, Song; Zhou, Teng; Wu, Junfeng; Li, Yin; Liu, Zhenyu; Xuan, Ming; Wu, Yihui

    2014-03-01

    Based on the Euler force induced by the acceleration of compact disk (CD)-like microfluidic chip, this paper presents a novel actuation mechanism for siphon valving. At the preliminary stage of acceleration, the Euler force in the tangential direction of CD-like chip takes the primary place compared with the centrifugal force to function as the actuation of the flow, which fills the siphon and actuates the siphon valving. The Euler force actuation mechanism is demonstrated by the numerical solution of the phase-field based mathematical model for the flow in siphon valve. In addition, experimental validation is implemented in the polymethylmethacrylate-based CD-like microfluidic chip manufactured using CO2 laser engraving technique. To prove the application of the proposed Euler force actuation mechanism, whole blood separation and plasma extraction has been conducted using the Euler force actuated siphon valving. The newly introduced actuation mechanism overcomes the dependence on hydrophilic capillary filling of siphon by avoiding external manipulation or surface treatments of polymeric material. The sacrifice for highly integrated processing in pneumatic pumping technique is also prevented by excluding the volume-occupied compressed air chamber. PMID:24753736

  14. Euler force actuation mechanism for siphon valving in compact disk-like microfluidic chips

    PubMed Central

    Deng, Yongbo; Fan, Jianhua; Zhou, Song; Zhou, Teng; Wu, Junfeng; Li, Yin; Liu, Zhenyu; Xuan, Ming; Wu, Yihui

    2014-01-01

    Based on the Euler force induced by the acceleration of compact disk (CD)-like microfluidic chip, this paper presents a novel actuation mechanism for siphon valving. At the preliminary stage of acceleration, the Euler force in the tangential direction of CD-like chip takes the primary place compared with the centrifugal force to function as the actuation of the flow, which fills the siphon and actuates the siphon valving. The Euler force actuation mechanism is demonstrated by the numerical solution of the phase-field based mathematical model for the flow in siphon valve. In addition, experimental validation is implemented in the polymethylmethacrylate-based CD-like microfluidic chip manufactured using CO2 laser engraving technique. To prove the application of the proposed Euler force actuation mechanism, whole blood separation and plasma extraction has been conducted using the Euler force actuated siphon valving. The newly introduced actuation mechanism overcomes the dependence on hydrophilic capillary filling of siphon by avoiding external manipulation or surface treatments of polymeric material. The sacrifice for highly integrated processing in pneumatic pumping technique is also prevented by excluding the volume-occupied compressed air chamber. PMID:24753736

  15. Development of an automated digestion and droplet deposition microfluidic chip for MALDI-TOF MS.

    PubMed

    Lee, Jeonghoon; Musyimi, Harrison K; Soper, Steven A; Murray, Kermit K

    2008-07-01

    An automated proteolytic digestion bioreactor and droplet deposition system was constructed with a plastic microfluidic device for off-line interfacing to matrix assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). The microfluidic chips were fabricated in poly(methyl methacrylate) (PMMA), using a micromilling machine and incorporated a bioreactor, which was 100 microm wide, 100 microm deep, and possessed a 4 cm effective channel length (400 nL volume). The chip was operated by pressure-driven flow and mounted on a robotic fraction collector system. The PMMA bioreactor contained surface immobilized trypsin, which was covalently attached to the UV-modified PMMA surface using coupling reagents N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride (EDC) and hydroxysulfosuccinimide (sulfo-NHS). The digested peptides were mixed with a MALDI matrix on-chip and deposited as discrete spots on MALDI targets. The bioreactor provided efficient digestion of a test protein, cytochrome c, at a flow rate of 1 microL/min, producing a reaction time of approximately 24 s to give adequate sequence coverage for protein identification. Other proteins were also evaluated using this solid-phase bioreactor. The efficiency of digestion was evaluated by monitoring the sequence coverage, which was 64%, 35%, 58%, and 47% for cytochrome c, bovine serum albumin (BSA), myoglobin, and phosphorylase b, respectively. PMID:18479934

  16. Preparation of monodisperse PEG hydrogel composite microspheres via microfluidic chip with rounded channels

    NASA Astrophysics Data System (ADS)

    Yu, Bing; Cong, Hailin; Liu, Xuesong; Ren, Yumin; Wang, Jilei; Zhang, Lixin; Tang, Jianguo; Ma, Yurong; Akasaka, Takeshi

    2013-09-01

    An effective microfluidic method to fabricate monodisperse polyethylene glycol (PEG) hydrogel composite microspheres with tunable dimensions and properties is reported in this paper. A T-junction microfluidic chip equipped with rounded channels and online photopolymerization system is applied for the microsphere microfabrication. The shape and size of the microspheres are well controlled by the rounded channels and PEG prepolymer/silicon oil flow rate ratios. The obtained PEG/aspirin composite microspheres exhibit a sustained release of aspirin for a wide time range; the obtained PEG/Fe3O4 nanocomposite microspheres exhibit excellent magnetic properties; and the obtained binary PEG/dye composite microspheres show the ability to synchronously load two functional components in the same peanut-shaped or Janus hydrogel particles.

  17. Microfluidics-Based Lab-on-Chip Systems in DNA-Based Biosensing: An Overview

    PubMed Central

    Dutse, Sabo Wada; Yusof, Nor Azah

    2011-01-01

    Microfluidics-based lab-on-chip (LOC) systems are an active research area that is revolutionising high-throughput sequencing for the fast, sensitive and accurate detection of a variety of pathogens. LOCs also serve as portable diagnostic tools. The devices provide optimum control of nanolitre volumes of fluids and integrate various bioassay operations that allow the devices to rapidly sense pathogenic threat agents for environmental monitoring. LOC systems, such as microfluidic biochips, offer advantages compared to conventional identification procedures that are tedious, expensive and time consuming. This paper aims to provide a broad overview of the need for devices that are easy to operate, sensitive, fast, portable and sufficiently reliable to be used as complementary tools for the control of pathogenic agents that damage the environment. PMID:22163925

  18. Study of individual erythrocyte deformability susceptibility to INFeD and ethanol using a microfluidic chip

    PubMed Central

    Liu, Lihong; Huang, Sha; Xu, Xiaoying; Han, Jongyoon

    2016-01-01

    Human red blood cells (RBCs) deformability in vitro was assessed during iron dextran (INFeD) loading and/or ethanol co-administration using microfluidic deformability screening. The results showed donor-specific variations in dose dependent deformability shift were revealed below 500 μg/mL iron dextran. Two out of nine blood samples exhibited significant cell stiffening at 500 μg/mL iron dextran loading concentration (p < 0.05, Tukey test). More interestingly, co-administration of moderate amount of ethanol was identified to have significant protective effects on RBC deformability. We also noted that ethanol can reverse the deformability of impaired RBCs. Meanwhile obvious donor dependent response to ethanol administration on RBC deformability was noted using our biomimetic microfluidic chip. PMID:26964754

  19. Research on microfluidic chip and imaging system used to measure Ca2+ in cell

    NASA Astrophysics Data System (ADS)

    Zhou, Wei; Zhang, Sixiang; Ran, Dugang; Liu, Bao

    2009-07-01

    The microfluidic fluorescence detecting system which is used to measure the concentration of Ca2+ had been designed. On the microfluidic chip we designed, cell-dyeing, cell fostering, reagent injecting and other operations can be completed. The monochromatic light came from optical monochromator which can emit continuous spectrum was used to excitated the fluorescent probe in the cell, then the fluorescence signal and image were sampled by the PMT and CCD, at last the data was processed and the content of Ca2+ in the cell was figured out by using the fluorescence ratio method. Meanwhile, by using the system, the dynamic curve of [Ca2+]1 in cell was given after being stimulated by high K+. The precise result verifies that the system is stable and credible and it meets the requirement of detecting [Ca2+]i in live cells in the filed of physiology.

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

    PubMed Central

    Perestrelo, Ana Rubina; Águas, Ana C. P.; Rainer, Alberto; Forte, Giancarlo

    2015-01-01

    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. PMID:26690442

  1. Heteronanojunctions with atomic size control using a lab-on-chip electrochemical approach with integrated microfluidics

    NASA Astrophysics Data System (ADS)

    Lunca Popa, P.; Dalmas, G.; Faramarzi, V.; Dayen, J. F.; Majjad, H.; Kemp, N. T.; Doudin, B.

    2011-05-01

    A versatile tool for electrochemical fabrication of heteronanojunctions with nanocontacts made of a few atoms and nanogaps of molecular spacing is presented. By integrating microfluidic circuitry in a lab-on-chip approach, we keep control of the electrochemical environment in the vicinity of the nanojunction and add new versatility for exchanging and controlling the junction's medium. Nanocontacts made of various materials by successive local controlled depositions are demonstrated, with electrical properties revealing sizes reaching a few atoms only. Investigations on benchmark molecular electronics material, trapped between electrodes, reveal the possibility to create nanogaps of size matching those of molecules. We illustrate the interest of a microfluidic approach by showing that exposure of a fabricated molecular junction to controlled high solvent flows can be used as a reliability criterion for the presence of molecular entities in a gap.

  2. Determination of Apparent Amylose Content in Rice by Using Paper-Based Microfluidic Chips.

    PubMed

    Hu, Xianqiao; Lu, Lin; Fang, Changyun; Duan, Binwu; Zhu, Zhiwei

    2015-11-11

    Determination of apparent amylose content in rice is a key function for rice research and the rice industry. In this paper, a novel approach with paper-based microfluidic chip is reported to determine apparent amylose content in rice. The conventional color reaction between amylose and iodine was employed. Blue color of amylose-iodine complex generated on-chip was converted to gray and measured with Photoshop after the colored chip was scanned. The method for preparation of the paper chip is described. In situ generation of iodine for on-chip color reaction was designed, and factors influencing color reaction were investigated in detail. Elimination of yellow color interference of excess iodine by exploiting color removal function of Photoshop was presented. Under the optimized conditions, apparent amylose content in rice ranging from 1.5 to 26.4% can be determined, and precision was 6.3%. The analytical results obtained with the developed approach were in good agreement with those with the continuous flow analyzer method. PMID:26495809

  3. Miniature interferometer for refractive index measurement in microfluidic chip

    NASA Astrophysics Data System (ADS)

    Chen, Minghui; Geiser, Martial; Truffer, Frederic; Song, Chengli

    2012-12-01

    The design and development of the miniaturized interferometer for measurement of the refractive index or concentration of sub-microliter volume aqueous solution in microfludic chip is presented. It is manifested by a successful measurement of the refractive index of sugar-water solution, by utilizing a laser diode for light source and the small robust instrumentation for practical implementation. Theoretically, the measurement principle and the feasibility of the system are analyzed. Experimental device is constructed with a diode laser, lens, two optical plate and a complementary metal oxide semiconductor (CMOS). Through measuring the positional changes of the interference fringes, the refractive index change are retrieved. A refractive index change of 10-4 is inferred from the measured image data. The entire system is approximately the size of half and a deck of cards and can operate on battery power for long time.

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

    PubMed Central

    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

  5. High-throughput particle manipulation by hydrodynamic, electrokinetic, and dielectrophoretic effects in an integrated microfluidic chip

    PubMed Central

    Li, Shunbo; Li, Ming; Bougot-Robin, Kristelle; Cao, Wenbin; Yeung Yeung Chau, Irene; Li, Weihua; Wen, Weijia

    2013-01-01

    Integrating different steps on a chip for cell manipulations and sample preparation is of foremost importance to fully take advantage of microfluidic possibilities, and therefore make tests faster, cheaper and more accurate. We demonstrated particle manipulation in an integrated microfluidic device by applying hydrodynamic, electroosmotic (EO), electrophoretic (EP), and dielectrophoretic (DEP) forces. The process involves generation of fluid flow by pressure difference, particle trapping by DEP force, and particle redirect by EO and EP forces. Both DC and AC signals were applied, taking advantages of DC EP, EO and AC DEP for on-chip particle manipulation. Since different types of particles respond differently to these signals, variations of DC and AC signals are capable to handle complex and highly variable colloidal and biological samples. The proposed technique can operate in a high-throughput manner with thirteen independent channels in radial directions for enrichment and separation in microfluidic chip. We evaluated our approach by collecting Polystyrene particles, yeast cells, and E. coli bacteria, which respond differently to electric field gradient. Live and dead yeast cells were separated successfully, validating the capability of our device to separate highly similar cells. Our results showed that this technique could achieve fast pre-concentration of colloidal particles and cells and separation of cells depending on their vitality. Hydrodynamic, DC electrophoretic and DC electroosmotic forces were used together instead of syringe pump to achieve sufficient fluid flow and particle mobility for particle trapping and sorting. By eliminating bulky mechanical pumps, this new technique has wide applications for in situ detection and analysis. PMID:24404011

  6. A Novel Electrochemical Microfluidic Chip Combined with Multiple Biomarkers for Early Diagnosis of Gastric Cancer

    NASA Astrophysics Data System (ADS)

    Xie, Yao; Zhi, Xiao; Su, Haichuan; Wang, Kan; Yan, Zhen; He, Nongyue; Zhang, Jingpu; Chen, Di; Cui, Daxiang

    2015-12-01

    Early diagnosis is very important to improve the survival rate of patients with gastric cancer and to understand the biology of cancer. In order to meet the clinical demands for early diagnosis of gastric cancer, we developed a disposable easy-to-use electrochemical microfluidic chip combined with multiple antibodies against six kinds of biomarkers (carcinoembryonic antigen (CEA), carbohydrate antigen 19-9 (CA19-9), Helicobacter pylori CagA protein (H.P.), P53oncoprotein (P53), pepsinogen I (PG I), and PG-II). The six kinds of biomarkers related to gastric cancer can be detected sensitively and synchronously in a short time. The specially designed three electrodes system enables cross-contamination to be avoided effectively. The linear ranges of detection of the electrochemical microfluidic chip were as follows: 0.37-90 ng mL-1 for CEA, 10.75-172 U mL-1 for CA19-9, 10-160 U L-1 for H.P., 35-560 ng mL-1 for P53, 37.5-600 ng mL-1 for PG I, and 2.5-80 ng mL-1for PG II. This method owns better sensitivity compared with enzyme-linked immunosorbent assay (ELISA) results of 394 specimens of gastric cancer sera. Furthermore, we established a multi-index prediction model based on the six kinds of biomarkers for predicting risk of gastric cancer. In conclusion, the electrochemical microfluidic chip for detecting multiple biomarkers has great potential in applications such as early screening of gastric cancer patients, and therapeutic evaluation, and real-time dynamic monitoring the progress of gastric cancer in near future.

  7. Microplasma generation in a sealed microfluidic glass chip using a water electrode

    NASA Astrophysics Data System (ADS)

    Jo, Kyoung-Woo; Kim, Man-Geun; Shin, Sang-Mo; Lee, Jong-Hyun

    2008-01-01

    A microplasma was generated in a sealed microfluidic glass chip for the application of the miniaturized chemical detection system, especially for water contaminants. The behavior of a microbubble as well as a microplasma was observed using a 1% NaCl solution with no metal contact in a sealed glass microchannel. A microplasma formed by water contents excluding air or inert gas showed clear emission spectrum in UV, visible, and near IR range. The detection of lead was demonstrated by measuring the intensity of the Pb emission line (at 406nm) with respect to the concentration.

  8. On-chip gradient generation in 256 microfluidic cell cultures: simulation and experimental validation.

    PubMed

    Somaweera, Himali; Haputhanthri, Shehan O; Ibraguimov, Akif; Pappas, Dimitri

    2015-08-01

    A microfluidic diffusion diluter was used to create a stable concentration gradient for dose response studies. The microfluidic diffusion diluter used in this study consisted of 128 culture chambers on each side of the main fluidic channel. A calibration method was used to find unknown concentrations with 12% error. Flow rate dependent studies showed that changing the flow rates generated different gradient patterns. Mathematical simulations using COMSOL Multi-physics were performed to validate the experimental data. The experimental data obtained for the flow rate studies agreed with the simulation results. Cells could be loaded into culture chambers using vacuum actuation and cultured for long times under low shear stress. Decreasing the size of the culture chambers resulted in faster gradient formation (20 min). Mass transport into the side channels of the microfluidic diffusion diluter used in this study is an important factor in creating the gradient using diffusional mixing as a function of the distance. To demonstrate the device's utility, an H2O2 gradient was generated while culturing Ramos cells. Cell viability was assayed in the 256 culture chambers, each at a discrete H2O2 concentration. As expected, the cell viability for the high concentration side channels increased (by injecting H2O2) whereas the cell viability in the low concentration side channels decreased along the chip due to diffusional mixing as a function of distance. COMSOL simulations were used to identify the effective concentration of H2O2 for cell viability in each side chamber at 45 min. The gradient effects were confirmed using traditional H2O2 culture experiments. Viability of cells in the microfluidic device under gradient conditions showed a linear relationship with the viability of the traditional culture experiment. Development of the microfluidic device used in this study could be used to study hundreds of concentrations of a compound in a single experiment. PMID:26050759

  9. Microfluidic Devices for Terahertz Spectroscopy of Live Cells Toward Lab-on-a-Chip Applications.

    PubMed

    Tang, Qi; Liang, Min; Lu, Yi; Wong, Pak Kin; Wilmink, Gerald J; Zhang, Donna; Xin, Hao

    2016-01-01

    THz spectroscopy is an emerging technique for studying the dynamics and interactions of cells and biomolecules, but many practical challenges still remain in experimental studies. We present a prototype of simple and inexpensive cell-trapping microfluidic chip for THz spectroscopic study of live cells. Cells are transported, trapped and concentrated into the THz exposure region by applying an AC bias signal while the chip maintains a steady temperature at 37 °C by resistive heating. We conduct some preliminary experiments on E. coli and T-cell solution and compare the transmission spectra of empty channels, channels filled with aqueous media only, and channels filled with aqueous media with un-concentrated and concentrated cells. PMID:27049392

  10. Acoustophoretic microfluidic chip for sequential elution of surface bound molecules from beads or cells

    PubMed Central

    Augustsson, Per; Malm, Johan; Ekström, Simon

    2012-01-01

    An acoustophoresis-based microfluidic flow-chip is presented as a novel platform to facilitate analysis of proteins and peptides loosely bound to the surface of beads or cells. The chip allows for direct removal of the background surrounding the beads or cells, followed by sequential treatment and collection of a sequence of up to five different buffer conditions. During this treatment, the beads/cells are retained in a single flow by acoustic radiation force. Eluted peptides are collected from the outlets and subsequently purified by miniaturized solid-phase extraction and analyzed with matrix assisted laser desorption mass spectrometry. Fundamental parameters such as the system fluidics and dispersion are presented. The device was successfully applied for wash and sequential elution of peptides bound to the surface of microbeads and human spermatozoa, respectively. PMID:24003343

  11. Microfluidic Devices for Terahertz Spectroscopy of Live Cells Toward Lab-on-a-Chip Applications

    PubMed Central

    Tang, Qi; Liang, Min; Lu, Yi; Wong, Pak Kin; Wilmink, Gerald J.; D. Zhang, Donna; Xin, Hao

    2016-01-01

    THz spectroscopy is an emerging technique for studying the dynamics and interactions of cells and biomolecules, but many practical challenges still remain in experimental studies. We present a prototype of simple and inexpensive cell-trapping microfluidic chip for THz spectroscopic study of live cells. Cells are transported, trapped and concentrated into the THz exposure region by applying an AC bias signal while the chip maintains a steady temperature at 37 °C by resistive heating. We conduct some preliminary experiments on E. coli and T-cell solution and compare the transmission spectra of empty channels, channels filled with aqueous media only, and channels filled with aqueous media with un-concentrated and concentrated cells. PMID:27049392

  12. Fabrication of microfluidic chips using lithographic patterning and adhesive bonding of the thick negative photoresist AZ 125 nXT

    NASA Astrophysics Data System (ADS)

    Knoll, Thorsten; Bergmann, Andreas; Nußbaum, Dominic

    2015-05-01

    In this work, for the first time the negative photoresist AZ 125 nXT was used for the fabrication of a microfluidic chip. Usually, fabrication of microfluidic devices on the basis of silicon or glass substrates is done by using the epoxy-based negative photoresist SU-8 or other thick film polymer materials. The suitability of SU-8 for various microfluidic applications has been shown in the fields of bioanalytic devices, lab-on-chip systems or microreaction technology. However, processing is always a very challenging task with regard to the adaptation of process parameters to the individual design and required functionality. Now, the AZ 125 nXT allows for the fabrication of structures in a wide thickness range with only one type of viscosity. In contrast to SU-8, the AZ 125 nXT is fully cross-linked during UV exposure and does not require a time-consuming post-exposure bake. 90 μm deep microfluidic channels were defined by lithographic patterning of AZ 125 nXT. Sealing of the open microfluidic channels was performed by a manual adhesive bonding process at a temperature of 100 °C. The fluidic function was successfully tested with flow rates up to 20 ml/min by means of a microfluidic edge connector. Long term stability and chemical resistance of the fabricated microfluidic channels will be investigated in the near future. The presented work shows the potential of AZ 125 nXT as a possible alternative to SU-8 for the fabrication of microfluidic chips.

  13. A novel microfluidic platform with stable concentration gradient for on chip cell culture and screening assays.

    PubMed

    Xu, Bi-Yi; Hu, Shan-Wen; Qian, Guang-Sheng; Xu, Jing-Juan; Chen, Hong-Yuan

    2013-09-21

    In this work a novel microfluidic platform for cell culture and assay is developed. On the chip a static cell culture region is coupled with dynamic fluidic nutrition supply structures. The cell culture unit has a sandwich structure with liquid channels on the top, the cell culture reservoir in the middle and gas channels on the bottom. Samples can be easily loaded into the reservoir and exchange constantly with the external liquid environment by diffusion. Since the flow direction is perpendicular to the liquid channel on the top of the reservoir, the cells in the reservoir are shielded from shear-force. By assembling the basic units into an array, a steady concentration gradient can be generated. Cell culture models both for continuous perfusion and one-off perfusion were established on the chip. Both adherent and suspended cells were successfully cultured on the chip in 2D and 3D culture modes. After culturing, the trapped cells were recovered for use in a later assay. As a competitive candidate for a standard cell culture and assay platform, this chip is also adaptable for cytotoxicity and cell growth assays. PMID:23884407

  14. All inkjet-printed electroactive polymer actuators for microfluidic lab-on-chip systems

    NASA Astrophysics Data System (ADS)

    Pabst, Oliver; Beckert, Erik; Perelaer, Jolke; Schubert, Ulrich S.; Eberhardt, Ramona; Tünnermann, Andreas

    2013-04-01

    Piezoelectric electroactive polymers (EAP) are promising materials for applications in microfluidic lab-on-chip systems. In such systems, fluids can be analyzed by different chemical or physical methods. During the analysis the fluids need to be distributed through the channels of the chip, which requires a pumping function. We present here all inkjet-printed EAP actuators that can be configured as a membrane-based micropump suitable for direct integration into lab-on-chip systems. Drop-on-demand inkjet printing is a versatile digital deposition technique that is capable of depositing various functional materials onto a wide variety of substrates in an additive way. Compared to conventional lithography-based processing it is cost-efficient and flexible, as no masking is required. The actuators consist of a polymer foil substrate with an inkjet-printed EAP layer sandwiched between a set of two electrodes. The actuators are printed using a commercially available EAP solution and silver nanoparticle inks. When a voltage is applied across the polymer layer, piezoelectric strain leads to a bending deflection of the beam or membrane. Circular membrane actuators with 20 mm diameter and EAP thicknesses of 10 to 15 μm exhibit deflections of several μm when driven at their resonance frequency with voltages of 110 V. From the behavior of membrane actuators a pumping rate of several 100 μL/min can be estimated, which is promising for applications in lab-on-chip devices.

  15. Microfluidic HPLC-Chip devices with integral channels containing methylstyrenic-based monolithic media.

    PubMed

    Robotti, Karla M; Yin, Hongfeng; Brennen, Reid; Trojer, Lukas; Killeen, Kevin

    2009-10-01

    Polyimide HPLC-Chip devices containing poly(methylstyrene-bis-p-vinylphenyl)ethane (MS/BVPE) stationary phase within the device channels and with wall attachment were prepared by thermally initiated free radical polymerization. The microfluidic devices were coupled to both UV and MS detectors. The potential of the MS/BVPE monolith as an alternative separation media within chip devices was investigated by side-by-side comparisons to particulate media within commercial devices. The chromatographic behavior of this stationary phase was comparable to particulate media for separations of proteins as the average peak width at half-height was equal (6.2 s) for a separation within 8 min under gradient elution conditions. The ability to control the porosity characteristics of the MS/BVPE monolith with changes in polymerization time also extended its utility into small analyte (< 500 Da) applications, although more optimization is needed to match conventional RP media for these applications. The good mechanical stability of the MS/BVPE monolith within the microdevices enabled excellent run-to-run repeatability (%RSD retention time (< or = 0.16) and chip-to-chip reproducibility (%RSD retention time (1.4). The use of this material within enrichment channels also shows its potential value in more complex work flows. PMID:19777457

  16. Interfacial tension based on-chip extraction of microparticles confined in microfluidic Stokes flows

    PubMed Central

    Huang, Haishui; He, Xiaoming

    2014-01-01

    Microfluidics involving two immiscible fluids (oil and water) has been increasingly used to produce hydrogel microparticles with wide applications. However, it is difficult to extract the microparticles out of the microfluidic Stokes flows of oil that have a Reynolds number (the ratio of inertia to viscous force) much less than one, where the dominant viscous force tends to drive the microparticles to move together with the surrounding oil. Here, we present a passive method for extracting hydrogel microparticles in microfluidic Stokes flow from oil into aqueous extracting solution on-chip by utilizing the intrinsic interfacial tension between oil and the microparticles. We further reveal that the thickness of an “extended confining layer” of oil next to the interface between oil and aqueous extracting solution must be smaller than the radius of microparticles for effective extraction. This method uses a simple planar merging microchannel design that can be readily fabricated and further integrated into a fluidic system to extract microparticles for wide applications. PMID:25378709

  17. [In situ photopolymerization of polyacrylamide-based preconcentrator on a microfluidic chip for capillary electrophoresis].

    PubMed

    Yamamoto, Sachio

    2012-01-01

    Microchip electrophoresis is widely used for microfluidics and has been studied extensively over the past decade. Translation of capillary electrophoresis methods from traditional capillary systems to a microchip platform provides rapid separation and easy quantitation of sample components. However, most microfluidic systems suffer from critical scaling problems. One promising solution to this problem is online sample preconcentration of all analytes in a sample reservoir before the separation channel. Herein, the following three techniques for online preconcentration during microchip electrophoresis are proposed: (1) in situ fabrication of an ionic polyacrylamide-based preconcentrator on a simple poly(methyl methacrylate) microfluidic chip for perm-selective preconcentration and capillary electrophoretic separation of anionic compounds, (2) simultaneous concentration enrichment and electrophoretic separation of weak acids on a microchip using an in situ photopolymerized carboxylate-type polyacrylamide gels as the perm-selective preconcentrator, and (3) microchip electrophoresis of oligosaccharides using lectin-immobilized preconcentrator gels fabricated by in situ photopolymerization. These techniques are expected to be powerful tools for clinical and pharmaceutical studies with on-line preconcentration during microchip electrophoresis. PMID:23023420

  18. Fabrication of a polystyrene microfluidic chip coupled to electrospray ionization mass spectrometry for protein analysis.

    PubMed

    Hu, Xianqiao; Dong, Yuanyuan; He, Qiaohong; Chen, Hengwu; Zhu, Zhiwei

    2015-05-15

    A highly integrated polystyrene (PS) microfluidic chip coupled to electrospray ionization mass spectrometry for on-chip protein digestion and online analysis was developed. The immobilized enzymatic microreactor for on-chip protein digestion was integrated onto microchip via the novel method of region-selective UV-modification combined with glutaraldehyde-based immobilization. The micro film electric contact for applying high voltage was prepared on chips by using UV-directed electroless plating technique. A micro-tip was machined at the end of main channel, serving as the interface between microchip and mass spectrometric detector. On-chip digestion and online detection of protein was carried out by coupling the microchip with mass spectrometry (MS). The influences of methanol flow rate in side channel on the stability of spray and intensity of signals were investigated systematically. Also the influence of sample flow rate on the performance of immobilized enzymatic reactor were investigated. Stable spray was obtained at the spray voltage of 2.8-3.0kV and the methanol flow rate of 500-700nLmin(-1) with the relative standard deviation (RSD) of total ion current (TIC) less than 10%. The influence of sample flow rate on the performance of immobilized enzymatic reactor was also studied. The sequence coverage of protein identification decreased with the increase of flow rate of the sample solution. A sequence coverage of 96% was obtained with immobilized enzymatic reactor at the sample flow rate of 100nLmin(-1) with the reaction time of 8.4min. It could detect cytochrome c as low as 10μgmL(-1) with the developed system. No obvious decrease in protein digestion efficiency was observed after the chip continuously performed for 4h and stored for 15d. PMID:25864010

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

    PubMed Central

    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

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

    PubMed

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

    2013-04-15

    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 force cost considerations to be kept low and throughput high. As such, 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 min with the ability to scale up 4 times 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

  1. Image Decoding of Photonic Crystal Beads Array in the Microfluidic Chip for Multiplex Assays

    PubMed Central

    Yuan, Junjie; Zhao, Xiangwei; Wang, Xiaoxia; Gu, Zhongze

    2014-01-01

    Along with the miniaturization and intellectualization of biomedical instruments, the increasing demand of health monitoring at anywhere and anytime elevates the need for the development of point of care testing (POCT). Photonic crystal beads (PCBs) as one kind of good encoded microcarriers can be integrated with microfluidic chips in order to realize cost-effective and high sensitive multiplex bioassays. However, there are difficulties in analyzing them towards automated analysis due to the characters of the PCBs and the unique detection manner. In this paper, we propose a strategy to take advantage of automated image processing for the color decoding of the PCBs array in the microfluidic chip for multiplex assays. By processing and alignment of two modal images of epi-fluorescence and epi-white light, every intact bead in the image is accurately extracted and decoded by PC colors, which stand for the target species. This method, which shows high robustness and accuracy under various configurations, eliminates the high hardware requirement of spectroscopy analysis and user-interaction software, and provides adequate supports for the general automated analysis of POCT based on PCBs array. PMID:25341876

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

    PubMed Central

    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

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

    PubMed

    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. Image decoding of photonic crystal beads array in the microfluidic chip for multiplex assays.

    PubMed

    Yuan, Junjie; Zhao, Xiangwei; Wang, Xiaoxia; Gu, Zhongze

    2014-01-01

    Along with the miniaturization and intellectualization of biomedical instruments, the increasing demand of health monitoring at anywhere and anytime elevates the need for the development of point of care testing (POCT). Photonic crystal beads (PCBs) as one kind of good encoded microcarriers can be integrated with microfluidic chips in order to realize cost-effective and high sensitive multiplex bioassays. However, there are difficulties in analyzing them towards automated analysis due to the characters of the PCBs and the unique detection manner. In this paper, we propose a strategy to take advantage of automated image processing for the color decoding of the PCBs array in the microfluidic chip for multiplex assays. By processing and alignment of two modal images of epi-fluorescence and epi-white light, every intact bead in the image is accurately extracted and decoded by PC colors, which stand for the target species. This method, which shows high robustness and accuracy under various configurations, eliminates the high hardware requirement of spectroscopy analysis and user-interaction software, and provides adequate supports for the general automated analysis of POCT based on PCBs array. PMID:25341876

  5. Image Decoding of Photonic Crystal Beads Array in the Microfluidic Chip for Multiplex Assays

    NASA Astrophysics Data System (ADS)

    Yuan, Junjie; Zhao, Xiangwei; Wang, Xiaoxia; Gu, Zhongze

    2014-10-01

    Along with the miniaturization and intellectualization of biomedical instruments, the increasing demand of health monitoring at anywhere and anytime elevates the need for the development of point of care testing (POCT). Photonic crystal beads (PCBs) as one kind of good encoded microcarriers can be integrated with microfluidic chips in order to realize cost-effective and high sensitive multiplex bioassays. However, there are difficulties in analyzing them towards automated analysis due to the characters of the PCBs and the unique detection manner. In this paper, we propose a strategy to take advantage of automated image processing for the color decoding of the PCBs array in the microfluidic chip for multiplex assays. By processing and alignment of two modal images of epi-fluorescence and epi-white light, every intact bead in the image is accurately extracted and decoded by PC colors, which stand for the target species. This method, which shows high robustness and accuracy under various configurations, eliminates the high hardware requirement of spectroscopy analysis and user-interaction software, and provides adequate supports for the general automated analysis of POCT based on PCBs array.

  6. A new on-chip ESI nozzle for coupling of MS with microfluidic devices.

    PubMed

    Schilling, M; Nigge, W; Rudzinski, A; Neyer, A; Hergenroder, R

    2004-06-01

    This paper presents a new on-chip electrospray ionisation (ESI) nozzle, which can be used as an interface for coupling microfluidic devices with mass spectrometric (MS) detection. The nozzle was micromilled in a polymer foil (polymethylmethacrylate (PMMA) 750 microm thick), normally used as a cover for microfluidic chips. The performance of this device was examined in the ESI-MS analysis of the tetrapeptide MRFA (methionine-argenine-phenylalanine-alanine). The spray quality is basically dependent on the inner diameter of the nozzle, beside the part of the organic modifier in the solution to be sprayed. Three different inner nozzle diameters (30, 50, 100 microm) and two different apex angles were investigated. Stable electrospray conditions can be generated with a relative standard deviation less than 10% of the total ion current, and down to a concentration of 0.01 micromol L(-1). The production of this ESI interface is relatively simple for the purpose of a low-cost batch fabrication of miniaturized analytical instruments. PMID:15159782

  7. The Evopopbot Chip: Ultra High-throughput Evolutionary Population Bottlenecking using Drop-Based Microfluidics

    NASA Astrophysics Data System (ADS)

    Chang, Connie; Rotem, Assaf; Serohijos, Adrian; Zhang, Huidan; Tao, Ye; Fischer Hesselbrock, Audrey; Thielen, Peter; Mehoke, Thomas; Wolfe, Joshua; Wobus, Christiane; Feldman, Andrew; Shakhnovich, Eugene; Weitz, David

    2014-03-01

    The study of how viruses propagate is important for curing disease and preventing viral outbreaks. In nature, viruses can compete with one another, and the most evolutionary fit virus usually takes over a population. Yet there exist variants in the population that can escape subjected evolutionary pressures and eventually dominate the population. Successful studies of viral epidemics hinges on the ability to access these variants. Here, we present the use of droplet-based microfluidics as a simple method to segregate and propagate a viral population as individual viral lineages, simultaneously performing millions of in vitroevolutionary bottlenecking experiments. We introduce a novel microfluidic device, called the ``Evopopbot Chip'', that allows for simultaneous passaging of millions of evolutionary bottlenecking events by splitting drops containing previous generations of viruses and merging with drops containing new host cells. After several generations of viral replication in the evolution chip, we discover hundreds of new viruses that are able to escape a neutralizing antibody selection pressure compared to bulk passaging.

  8. Soil-on-a-Chip: microfluidic platforms for environmental organismal studies.

    PubMed

    Stanley, Claire E; Grossmann, Guido; i Solvas, Xavier Casadevall; deMello, Andrew J

    2016-01-21

    Soil is the habitat of countless organisms and encompasses an enormous variety of dynamic environmental conditions. While it is evident that a thorough understanding of how organisms interact with the soil environment may have substantial ecological and economical impact, current laboratory-based methods depend on reductionist approaches that are incapable of simulating natural diversity. The application of Lab-on-a-Chip or microfluidic technologies to organismal studies is an emerging field, where the unique benefits afforded by system miniaturisation offer new opportunities for the experimentalist. Indeed, precise spatiotemporal control over the microenvironments of soil organisms in combination with high-resolution imaging has the potential to provide an unprecedented view of biological events at the single-organism or single-cell level, which in turn opens up new avenues for environmental and organismal studies. Herein we review some of the most recent and interesting developments in microfluidic technologies for the study of soil organisms and their interactions with the environment. We discuss how so-called "Soil-on-a-Chip" technology has already contributed significantly to the study of bacteria, nematodes, fungi and plants, as well as inter-organismal interactions, by advancing experimental access and environmental control. Most crucially, we highlight where distinct advantages over traditional approaches exist and where novel biological insights will ensue. PMID:26645910

  9. Microfluidic chip with electrochemiluminescence detection using 2-(2-aminoethyl)-1-methylpyrrolidine labeling.

    PubMed

    Yin, Xue-Bo; Du, Yan; Yang, Xiurong; Wang, Erkang

    2005-10-14

    A tertiary amine derivative, 2-(2-aminoethyl)-1-methylpyrrolidine (AEMP) was successfully developed as electrochemiluminescence (ECL) probe within microfluidic chip using ECL detection in this paper. The system was characterized by the interaction between biotin and avidin. In principle, tertiary amine derivatives containing active group can be used as a potential alternative of traditional tris(2,2'-bipyridine)ruthenium(II) [Ru(bpy)3(2+)] label. Firstly, The ECL efficiency of AEMP was characterized via comparing with that of two coreactants enhancing Ru(bpy)3(2+) ECL, TPA and proline. At same condition, AEMP has a similar ECL efficiency to TPA, and much higher than proline. After AEMP reacted with NHS-LC-biotin (succinimidyl-6-(biotinamido) hexanoate), the products and their ECL were analyzed by directly injecting it in the microfluidic chip. A 4.5 cm microchannel was used to separate the mixture of AEMP and biotinylated AEMP. The present works indicated that AEMP has a good reactivity to the analytes containing carboxyl group with a similar ECL efficiency to TPA. Under optimal condition, the detection limits (based on 3 S/N) of AEMP was 2.7 microM. The system was also validated by the reaction between biotin and avidin. The calculated binding ratio between avidin and biotin based on the present method was 4.4. PMID:16395805

  10. A spring-driven press device for hot embossing and thermal bonding of PMMA microfluidic chips.

    PubMed

    Chen, Zhi; Zhang, Luyan; Chen, Gang

    2010-08-01

    A novel spring-driven press device was designed and manufactured for hot embossing and thermal bonding of PMMA microfluidic chips in this work. This simple device consisted of two semi-cylinder silicone rubber press heads, three steel clamping plates, and three compression springs that were assembled together using two screw bolts and two butterfly nuts. The three springs were clamped between the upper and the middle clamping plates, whereas the two press heads were assembled between the middle and the lower clamping plates. After an epoxy template covered by a PMMA plate or a PMMA channel plate together with a cover were sandwiched between two microscopic glass slides for embossing or bonding, respectively, they were clamped between the two elastic press heads of the press device by fastening the screw nuts on the upper clamping plate. Because the convex press heads applied pressure along the middle line of the glass slides, they would deform resulting in a negative pressure gradient from the middle to the sides so that air bubbles between the sandwiched parts could be squeezed out during embossing and bonding processes. High-quality PMMA microfluidic chips were prepared by using this unique device and were successfully applied in the electrophoretic separation of several cations. PMID:20665912

  11. Single-Cell Chemical Lysis on Microfluidic Chips with Arrays of Microwells

    PubMed Central

    Jen, Chun-Ping; Hsiao, Ju-Hsiu; Maslov, Nikolay A.

    2012-01-01

    Many conventional biochemical assays are performed using populations of cells to determine their quantitative biomolecular profiles. However, population averages do not reflect actual physiological processes in individual cells, which occur either on short time scales or nonsynchronously. Therefore, accurate analysis at the single-cell level has become a highly attractive tool for investigating cellular content. Microfluidic chips with arrays of microwells were developed for single-cell chemical lysis in the present study. The cellular occupancy in 30-μm-diameter microwells (91.45%) was higher than that in 20-μm-diameter microwells (83.19%) at an injection flow rate of 2.8 μL/min. However, most of the occupied 20-μm-diameter microwells contained individual cells. The results of chemical lysis experiments at the single-cell level indicate that cell membranes were gradually lysed as the lysis buffer was injected; they were fully lysed after 12 s. Single-cell chemical lysis was demonstrated in the proposed microfluidic chip, which is suitable for high-throughput cell lysis. PMID:22368473

  12. Microfluidic Chip for Molecular Amplification of Influenza A RNA in Human Respiratory Specimens

    PubMed Central

    Chang, Jessie; Carey, Brendan; Hsieh, Christopher; Stanley, Ahjegannie; Odell, Christine A.; Mitchell, Patricia; Feldman, James; Pollock, Nira R.; Klapperich, Catherine M.

    2012-01-01

    A rapid, low cost, accurate point-of-care (POC) device to detect influenza virus is needed for effective treatment and control of both seasonal and pandemic strains. We developed a single-use microfluidic chip that integrates solid phase extraction (SPE) and molecular amplification via a reverse transcription polymerase chain reaction (RT-PCR) to amplify influenza virus type A RNA. We demonstrated the ability of the chip to amplify influenza A RNA in human nasopharyngeal aspirate (NPA) and nasopharyngeal swab (NPS) specimens collected at two clinical sites from 2008–2010. The microfluidic test was dramatically more sensitive than two currently used rapid immunoassays and had high specificity that was essentially equivalent to the rapid assays and direct fluorescent antigen (DFA) testing. We report 96% (CI 89%,99%) sensitivity and 100% (CI 95%,100%) specificity compared to conventional (bench top) RT-PCR based on the testing of n = 146 specimens (positive predictive value = 100%(CI 94%,100%) and negative predictive value = 96%(CI 88%,98%)). These results compare well with DFA performed on samples taken during the same time period (98% (CI 91%,100%) sensitivity and 96%(CI 86%,99%) specificity compared to our gold standard testing). Rapid immunoassay tests on samples taken during the enrollment period were less reliable (49%(CI 38%,61%) sensitivity and 98%(CI 98%,100%) specificity). The microfluidic test extracted and amplified influenza A RNA directly from clinical specimens with viral loads down to 103 copies/ml in 3 h or less. The new test represents a major improvement over viral culture in terms of turn around time, over rapid immunoassay tests in terms of sensitivity, and over bench top RT-PCR and DFA in terms of ease of use and portability. PMID:22457740

  13. From microfluidic modules to an integrated Lab-on-a-chip system for the detection of Francisella tularensis

    NASA Astrophysics Data System (ADS)

    Hlawatsch, Nadine; Krumbholz, Marco; Prüfer, Anna; Moche, Christian; Becker, Holger; Gärtner, Claudia

    2013-05-01

    Lab-on-a-chip (LoC) systems translating the whole process of pathogen analysis to an integrated, miniaturized, and automatically functioning microfluidic platform are generally expected to be very promising future diagnostic approaches. The development of such a LoC system for the detection of bacterial pathogens applied to the example pathogen Francisella tularensis is described in this report. To allow functional testing of the whole process cascade before final device integration, various bio-analytical steps such as cell lysis, DNA extraction and purification, continuous-flow PCR and analyte detection have been adapted to unique functional microfluidic modules. As a successive step, positively tested modules for pathogen detection have been successfully assembled to an integrated chip. Moreover, technical solutions for a smooth interaction between sample input from the outer world as well as microfluidic chip and chip driving instrument have been developed. In conclusion, a full repertoire of analytical tools have been developed and successfully tested in the concerted manner of a functionally integrated microfluidic device representing a tool for future diagnostic approaches.

  14. 10 000-fold concentration increase of the biomarker cardiac troponin I in a reducing union microfluidic chip using cationic isotachophoresis†

    PubMed Central

    Bottenus, Danny; Jubery, Talukder Zaki; Ouyang, Yexin; Dong, Wen-Ji; Dutta, Prashanta

    2011-01-01

    This paper describes the preconcentration of the biomarker cardiac troponin I (cTnI) and a fluorescent protein (R-phycoerythrin) using cationic isotachophoresis (ITP) in a 3.9 cm long poly(methyl methacrylate) (PMMA) microfluidic chip. The microfluidic chip includes a channel with a 5× reduction in depth and a 10× reduction in width. Thus, the overall cross-sectional area decreases by 50× from inlet (anode) to outlet (cathode). The concentration is inversely proportional to the cross-sectional area so that as proteins migrate through the reductions, the concentrations increase proportionally. In addition, the proteins gain additional concentration by ITP. We observe that by performing ITP in a cross-sectional area reducing microfluidic chip we can attain concentration factors greater than 10 000. The starting concentration of cTnI was 2.3 μg mL–1 and the final concentration after ITP concentration in the microfluidic chip was 25.52 ± 1.25 mg mL–1. To the author's knowledge this is the first attempt at concentrating the cardiac biomarker cTnI by ITP. This experimental approach could be coupled to an immunoassay based technique and has the potential to lower limits of detection, increase sensitivity, and quantify different isolated cTnI phosphorylation states. PMID:21308695

  15. 10 000-fold concentration increase of the biomarker cardiac troponin I in a reducing union microfluidic chip using cationic isotachophoresis†

    PubMed Central

    Bottenus, Danny; Jubery, Talukder Zaki; Ouyang, Yexin; Dong, Wen-Ji; Dutta, Prashanta

    2012-01-01

    This paper describes the preconcentration of the biomarker cardiac troponin I (cTnI) and a fluorescent protein (R-phycoerythrin) using cationic isotachophoresis (ITP) in a 3.9 cm long poly(methyl methacrylate) (PMMA) microfluidic chip. The microfluidic chip includes a channel with a 5× reduction in depth and a 10× reduction in width. Thus, the overall cross-sectional area decreases by 50× from inlet (anode) to outlet (cathode). The concentration is inversely proportional to the cross-sectional area so that as proteins migrate through the reductions, the concentrations increase proportionally. In addition, the proteins gain additional concentration by ITP. We observe that by performing ITP in a cross-sectional area reducing microfluidic chip we can attain concentration factors greater than 10 000. The starting concentration of cTnI was 2.3 μg mL−1 and the final concentration after ITP concentration in the microfluidic chip was 25.52 ± 1.25 mg mL−1. To the author’s knowledge this is the first attempt at concentrating the cardiac biomarker cTnI by ITP. This experimental approach could be coupled to an immunoassay based technique and has the potential to lower limits of detection, increase sensitivity, and quantify different isolated cTnI phosphorylation states. PMID:21416810

  16. An on-chip microfluidic pressure regulator that facilitates reproducible loading of cells and hydrogels into microphysiological system platforms.

    PubMed

    Wang, Xiaolin; Phan, Duc T T; Zhao, Da; George, Steven C; Hughes, Christopher C W; Lee, Abraham P

    2016-03-01

    Coculturing multiple cell types together in 3-dimensional (3D) cultures better mimics the in vivo microphysiological environment, and has become widely adopted in recent years with the development of organ-on-chip systems. However, a bottleneck in set-up of these devices arises as a result of the delivery of the gel into the microfluidic chip being sensitive to pressure fluctuations, making gel confinement at a specific region challenging, especially when manual operation is performed. In this paper, we present a novel design of an on-chip regulator module with pressure-releasing safety microvalves that can facilitate stable gel delivery into designated microchannel regions while maintaining well-controlled, non-bursting gel interfaces. This pressure regulator design can be integrated into different microfluidic chip designs and is compatible with a wide variety of gel injection apparatuses operated automatically or manually at different flow rates. The sensitivity and working range of this pressure regulator can be adjusted by changing the width of its pressure releasing safety microvalve design. The effectiveness of the design is validated by its incorporation into a microfluidic platform we have developed for generating 3D vascularized micro-organs (VMOs). Reproducible gel loading is demonstrated for both an automatic syringe pump and a manually-operated micropipettor. This design allows for rapid and reproducible loading of hydrogels into microfluidic devices without the risk of bursting gel-air interfaces. PMID:26879519

  17. A Low-Cost Microfluidic Chip for Rapid Genotyping of Malaria-Transmitting Mosquitoes

    PubMed Central

    Liu, Changchun; Mauk, Michael G.; Hart, Robert; Bonizzoni, Mariangela; Yan, Guiyun; Bau, Haim H.

    2012-01-01

    Background Vector control is one of the most effective measures to prevent the transmission of malaria, a disease that causes over 600,000 deaths annually. Around 30–40 Anopheles mosquito species are natural vectors of malaria parasites. Some of these species cannot be morphologically distinguished, but have behavioral and ecological differences. Emblematic of this is the Anopheles gambiae species complex. The correct identification of vector species is fundamental to the development of control strategies and epidemiological studies of disease transmission. Methodology/Principal Findings An inexpensive, disposable, field-deployable, sample-to-answer, microfluidic chip was designed, constructed, and tested for rapid molecular identification of Anopheles gambiae and Anopheles arabiensis. The chip contains three isothermal amplification reactors. One test reactor operates with specific primers to amplify Anopheles gambiae DNA, another with specific primers for Anopheles arabiensis DNA, and the third serves as a negative control. A mosquito leg was crushed on an isolation membrane. Two discs, laden with mosquito tissue, were punched out of the membrane and inserted into the two test chambers. The isolated, disc-bound DNA served as a template in the amplification processes. The amplification products were detected with intercalating fluorescent dye that was excited with a blue light-emitting diode. The emitted light was observed by eye and recorded with a cell-phone camera. When the target consisted of Anopheles gambiae, the reactor containing primers specific to An. gambiae lit up while the other two reactors remained dark. When the target consisted of Anopheles arabiensis, the reactor containing primers specific to An. arabiensis lit up while the other two reactors remained dark. Conclusions/Significance The microfluidic chip provides a means to identify mosquito type through molecular analysis. It is suitable for field work, allowing one to track the geographical

  18. From bioseparation to artificial micro-organs: microfluidic chip based particle manipulation techniques

    NASA Astrophysics Data System (ADS)

    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.

  19. Microfluidic Pneumatic Cages: A Novel Approach for In-chip Crystal Trapping, Manipulation and Controlled Chemical Treatment.

    PubMed

    Abrishamkar, Afshin; Paradinas, Markos; Bailo, Elena; Rodriguez-Trujillo, Romen; Pfattner, Raphael; Rossi, René M; Ocal, Carmen; deMello, Andrew J; Amabilino, David B; Puigmartí-Luis, Josep

    2016-01-01

    The precise localization and controlled chemical treatment of structures on a surface are significant challenges for common laboratory technologies. Herein, we introduce a microfluidic-based technology, employing a double-layer microfluidic device, which can trap and localize in situ and ex situ synthesized structures on microfluidic channel surfaces. Crucially, we show how such a device can be used to conduct controlled chemical reactions onto on-chip trapped structures and we demonstrate how the synthetic pathway of a crystalline molecular material and its positioning inside a microfluidic channel can be precisely modified with this technology. This approach provides new opportunities for the controlled assembly of structures on surface and for their subsequent treatment. PMID:27500740

  20. Using Microfluidics Chips for Live Imaging and Study of Injury Responses in Drosophila Larvae

    PubMed Central

    Mishra, Bibhudatta; Ghannad-Rezaie, Mostafa; Li, Jiaxing; Wang, Xin; Hao, Yan; Ye, Bing; Chronis, Nikos; Collins, Catherine A.

    2014-01-01

    Live imaging is an important technique for studying cell biological processes, however this can be challenging in live animals. The translucent cuticle of the Drosophila larva makes it an attractive model organism for live imaging studies. However, an important challenge for live imaging techniques is to noninvasively immobilize and position an animal on the microscope. This protocol presents a simple and easy to use method for immobilizing and imaging Drosophila larvae on a polydimethylsiloxane (PDMS) microfluidic device, which we call the 'larva chip'. The larva chip is comprised of a snug-fitting PDMS microchamber that is attached to a thin glass coverslip, which, upon application of a vacuum via a syringe, immobilizes the animal and brings ventral structures such as the nerve cord, segmental nerves, and body wall muscles, within close proximity to the coverslip. This allows for high-resolution imaging, and importantly, avoids the use of anesthetics and chemicals, which facilitates the study of a broad range of physiological processes. Since larvae recover easily from the immobilization, they can be readily subjected to multiple imaging sessions. This allows for longitudinal studies over time courses ranging from hours to days. This protocol describes step-by-step how to prepare the chip and how to utilize the chip for live imaging of neuronal events in 3rd instar larvae. These events include the rapid transport of organelles in axons, calcium responses to injury, and time-lapse studies of the trafficking of photo-convertible proteins over long distances and time scales. Another application of the chip is to study regenerative and degenerative responses to axonal injury, so the second part of this protocol describes a new and simple procedure for injuring axons within peripheral nerves by a segmental nerve crush. PMID:24562098

  1. Laser vibrometry characterisation of a microfluidic lab-on-a-chip device: a preliminary investigation

    NASA Astrophysics Data System (ADS)

    Fury, C.; Gélat, P. N.; Jones, P. H.; Memoli, G.

    2014-04-01

    Since their original inception as ultrasound contrast agents, potential applications of microbubbles have evolved to encompass molecular imaging and targeted drug delivery. As these areas develop, so does the need to understand the mechanisms behind the interaction of microbubbles both with biological tissue and with other microbubbles. There is therefore a metrological requirement to develop a controlled environment in which to study these processes. Presented here is the design and characterisation of such a system, which consists of a microfluidic chip, specifically developed for manipulating microbubbles using both optical and acoustic trapping. A laser vibrometer is used to observe the coupling of acoustic energy into the chip from a piezoelectric transducer bonded to the surface. Measurement of the velocity of surface waves on the chip is investigated as a potential method for inferring the nature of the acoustic fields excited within the liquid medium of the device. Comparison of measured surface wavelengths with wave types suggests the observation of anti-symmetric Lamb or Love-Kirchhoff waves. Further visual confirmation of the acoustic fields through bubble aggregation highlights differences between the model and experimental results in predicting the position of acoustic pressure nodes in relation to excitation frequency.

  2. Biomolecule storage on non-modified thermoplastic microfluidic chip by ink-jet printing of ionogels

    PubMed Central

    Tijero, M.; Díez-Ahedo, R.; Benito-Lopez, F.; Basabe-Desmonts, L.; Castro-López, V.; Valero, A.

    2015-01-01

    This paper reports an innovative technique for reagents storage in microfluidic devices by means of a one-step UV-photoprintable ionogel-based microarray on non-modified polymeric substrates. Although the ionogel and the ink-jet printing technology are well published, this is the first study where both are used for long-term reagent storage in lab-on-a-chip devices. This technology for reagent storage is perfectly compatible with mass production fabrication processes since pre-treatment of the device substrate is not necessary and inkjet printing allows for an efficient reagent deposition process. The functionality of this microarray is demonstrated by testing the release of biotin-647 after being stored for 1 month at room temperature. Analysis of the fluorescence of the ionogel-based microarray that contains biotin-647 demonstrated that 90% of the biotin-647 present was released from the ionogel-based microarray after pumping PBS 0.1% Tween at 37 °C. Moreover, the activity of biotin-647 after being released from the ionogel-based microarray was investigated trough the binding capability of this biotin to a microcontact printed chip surface with avidin. These findings pave the way for a novel, one-step, cheap and mass production on-chip reagents storage method applicable to other reagents such as antibodies and proteins and enzymes. PMID:26339323

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

    PubMed

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

    2015-12-15

    Polymerase chain reaction (PCR)-based genetic testing has become a routine part of clinical diagnoses and food testing. In these fields, rapid, easy-to-use, and cost-efficient PCR chips are expected to be appeared for providing such testing on-site. In this study, a new autonomous disposable plastic microfluidic PCR chip was created, and was utilized for quantitative detection of pathogenic microorganisms. To control the capillary flow of the following solution in the PCR microchannel, a driving microchannel was newly designed behind the PCR microchannel. This allowed the effective PCR by simply dropping the PCR solution onto the inlet without any external pumps. In order to achieve disposability, injection-molded cyclo-olefin polymer (COP) of a cost-competitive plastic was used for the PCR chip. We discovered that coating the microchannel walls with non-ionic surfactant produced a suitable hydrophilic surface for driving the capillary flow through the 1250-mm long microchannel. As a result, quantitative real-time PCR with the lowest initial concentration of human, Escherichia coli (E. coli), and pathogenic E. coli O157 genomic DNA of 4, 0.0019, 0.031 pg/μl, respectively, was successfully achieved in less than 18 min. Our results indicate that the platform presented in this study provided a rapid, easy-to-use, and low-cost real-time PCR system that could be potentially used for on-site gene testing. PMID:26210470

  4. Single cell membrane poration by bubble-induced microjets in a microfluidic chip.

    PubMed

    Li, Z G; Liu, A Q; Klaseboer, E; Zhang, J B; Ohl, C D

    2013-03-21

    This paper demonstrates membrane poration of a single suspension cell due to a fast liquid microjet. The jet is formed during the collapse of a laser induced bubble created at a variable stand-off distance from the target cell. The cell is trapped by a converging structure within a microfluidic chip. The asymmetrical growth and collapse of the cavitation bubble next to the cell lead to the microjetting, which deforms and porates the cell membrane. In the experiments, the membrane porations of myeloma cells are probed with the uptake of trypan blue. Time-resolved studies of the diffusion of trypan blue show a marked dependency on the bubble dynamics, i.e. the stand-off distance. The penetration length of the dye increases with shorter distances. Numerical simulations of the diffusion process agree with larger pores formed on the cell membrane. This method allows for a fast, repeatable, and localized rupture of membranes of individual cells in suspension. PMID:23364762

  5. High throughput assay of diffusion through Cx43 gap junction channels with a microfluidic chip.

    PubMed

    Bathany, Cédric; Beahm, Derek; Felske, James D; Sachs, Frederick; Hua, Susan Z

    2011-02-01

    This paper describes a microfluidic-based assay capable of measuring gap-junction mediated dye diffusion in cultured cells. The technique exploits multistream laminar flow to selectively expose cells to different environments, enabling continuous loading of cells in one compartment while monitoring, in real time, dye diffusion into cells of a neighboring compartment. A simple one-dimensional diffusion model fit to the data extracted the diffusion coefficient of four different dyes, 5-(6)-carboxyfluorescein, 5-chloromethylfluorescein, Oregon green 488 carboxylic acid, and calcein. Different inhibitors were assayed for their ability to reduce dye coupling. The chip can screen multiple inhibitors in parallel in the same cell preparation, demonstrating its potential for high throughput. The technique provides a convenient method to measure gap junction mediated diffusion and a screen for drugs that affect gap junction communication. PMID:21182279

  6. An integrated microfluidic chip for immunomagnetic detection and isolation of rare prostate cancer cells from blood.

    PubMed

    Esmaeilsabzali, Hadi; Beischlag, Timothy V; Cox, Michael E; Dechev, Nikolai; Parameswaran, Ash M; Park, Edward J

    2016-02-01

    The quantitative and qualitative analysis of circulating tumor cells (CTCs) has the potential to improve the clinical management of several cancers, including prostate cancer. As such, there is much interest in the isolation of CTCs from the peripheral blood of cancer patients. We report the design, fabrication, and proof-of-principle testing of an integrated permalloy-based microfluidic chip for immunomagnetic isolation of blood-borne prostate cancer cells using an antibody targeting prostate surface membrane antigen (PSMA). The preliminary results using spiked blood samples indicate that the proposed device is consistently capable of isolating prostate cancer cells with high sensitivity (up to 98 %) at clinically relevant low concentrations (down to 20 cells/mL) and an acceptable throughput (100 μL/min). PMID:26876965

  7. Development of interferometer for refractive index measurement of aqueous solution in a microfluidic chip

    NASA Astrophysics Data System (ADS)

    Chen, M. H.; Geiser, M.; Truffer, F.; Song, C. L.

    2013-04-01

    This study presents the design and development of an interferometer for the measurement of the refractive index or concentration of a sub-microliter volume of aqueous solution in a microfluidic chip. This proposed interferometer is manifested by the successful measurement of the refractive index of a sugar-water solution, using a He-Ne laser as a light source and robust instrumentation for practical implementation. The measurement principle and the feasibility of the system are analyzed theoretically. The experimental device is constructed with a He-Ne laser, two lenses, two optical plates and a complementary metal oxide semiconductor detector. The refractive index change is determined by measuring the positional changes of the interference fringes. A refractive index change of 10-4 is inferred from the measured image data.

  8. Single-bead arrays for fluorescence-based immunoassays on capillary-driven microfluidic chips

    NASA Astrophysics Data System (ADS)

    Temiz, Yuksel; Lim, Michel; Delamarche, Emmanuel

    2016-03-01

    We report a concept for the simple fabrication of easy-to-use chips for immunoassays in the context of point-of-care diagnostics. The chip concept comprises mainly three features: (1) the efficient integration of reagents using beads functionalized with receptors, (2) the generation of capillary-driven liquid flows without using external pumps, and (3) a high-sensitivity detection of analytes using fluorescence microscopy. We fabricated prototype chips using dry etching of Si wafers. 4.5-μm-diameter beads were integrated into hexagonal arrays by sedimentation and removing the excess using a stream of water. We studied the effect of different parameters and showed that array occupancies from 30% to 50% can be achieved by pipetting a 250 nL droplet of 1% bead solution and allowing the beads sediment for 3 min. Chips with integrated beads were sealed using a 50-μm-thick dry-film resist laminated at 45 °C. Liquids pipetted to loading pads were autonomously pulled by capillary pumps at a rate of 0.35 nL s-1 for about 30 min. We studied ligand-receptor interactions and binding kinetics using time-lapse fluorescence microscopy and demonstrated a 5 pM limit of detection (LOD) for an anti-biotin immunoassay. As a clinically-relevant example, we implemented an immunoassay to detect prostate specific antigen (PSA) and showed an LOD of 108 fM (i.e. 3.6 pg mL-1). While a specific implementation is provided here for the detection of PSA, we believe that combining capillary-driven microfluidics with arrays of single beads and fluorescence readout to be very flexible and sufficiently sensitive for the detection of other clinically-relevant analytes.

  9. Generation of Monodisperse Liquid Droplets in a Microfluidic Chip Using a High-Speed Gaseous Microflow

    NASA Astrophysics Data System (ADS)

    Tirandazi, Pooyan; Hidrovo, Carlos

    2015-11-01

    Over the last few years, microfluidic systems known as Lab-on-a-Chip (LOC) and micro total analysis systems (μTAS) have been increasingly developed as essential components for numerous biochemical applications. Droplet microfluidics, however, provides a distinctive attribute for delivering and processing discrete as well as ultrasmall volumes of fluid, which make droplet-based systems more beneficial over their continuous-phase counterparts. Droplet generation in its conventional scheme usually incorporates the injection of a liquid (water) into a continuous immiscible liquid (oil) medium. In this study we demonstrate a novel scheme for controlled generation of monodisperse droplets in confined gas-liquid microflows. We experimentally investigate the manipulation of water droplets in flow-focusing configurations using a high inertial air stream. Different flow regimes are observed by varying the gas and liquid flow rates, among which, the ``dripping regime'' where monodisperse droplets are generated is of great importance. The controlled size and generation rate of droplets in this region provide the capability for precise and contaminant-free delivery of microliter to nanoliter volumes of fluid. Furthermore, the high speed droplets generated in this method represent the basis for a new approach based on droplet pair collisions for fast efficient micromixing which provides a significant development in modern LOC and μTAS devices. This project is currently being supported by an NSF CAREER Award grant CBET-1151091.

  10. Microfluidic chip with optical sensor for rapid detection of nerve agent Sarin in water samples

    NASA Astrophysics Data System (ADS)

    Tan, Hsih Yin; Nguyen, Nam-Trung; Loke, Weng Keong; Tan, Yong Teng

    2007-12-01

    The chemical warfare agent Sarin is an organophosphate that is highly toxic to humans as they can act as cholinesterase inhibitors, that disrupts neuromuscular transmission. As these nerve agents are colorless, odorless and highly toxic, they can be introduced into drinking water as a means of terrorist sabotage. Hence, numerous innovative devices and methods have been developed for rapid detection of these organophosphates. Microfluidic technology allows the implementation of fast and sensitive detection of Sarin. In this paper, a micro-total analysis systems (TAS), also known as Lab-on-a-chip, fitted with an optical detection system has been developed to analyze the presence of the nerve agent sarin in water samples. In the present set-up, inhibition of co-introduced cholinesterase and water samples containing trace amounts of nerve agent sarin into the microfluidic device was used as the basis for selective detection of sarin. The device was fabricated using polymeric micromachining with PMMA (poly (methymethacrylate)) as the substrate material. A chromophore was utilized to measure the activity of remnant cholinesterase activity, which is inversely related to the amount of sarin present in the water samples. Comparisons were made between two different optical detection techniques and the findings will be presented in this paper. The presented measurement method is simple, fast and as sensitive as Gas Chromatography.

  11. Enhanced cell sorting and manipulation with combined optical tweezer and microfluidic chip technologies.

    PubMed

    Wang, Xiaolin; Chen, Shuxun; Kong, Marco; Wang, Zuankai; Costa, Kevin D; Li, Ronald A; Sun, Dong

    2011-11-01

    Sorting (or isolation) and manipulation of rare cells with high recovery rate and purity are of critical importance to a wide range of physiological applications. In the current paper, we report on a generic single cell manipulation tool that integrates optical tweezers and microfluidic chip technologies for handling small cell population sorting with high accuracy. The laminar flow nature of microfluidics enables the targeted cells to be focused on a desired area for cell isolation. To recognize the target cells, we develop an image processing methodology with a recognition capability of multiple features, e.g., cell size and fluorescence label. The target cells can be moved precisely by optical tweezers to the desired destination in a noninvasive manner. The unique advantages of this sorter are its high recovery rate and purity in small cell population sorting. The design is based on dynamic fluid and dynamic light pattern, in which single as well as multiple laser traps are employed for cell transportation, and a recognition capability of multiple cell features. Experiments of sorting yeast cells and human embryonic stem cells are performed to demonstrate the effectiveness of the proposed cell sorting approach. PMID:21918752

  12. Fabrication and characterization of microfluidic liver-on-a-chip using microsomal enzymes.

    PubMed

    Lee, Jungwoo; Kim, Si Hyeon; Kim, Young-Chan; Choi, Inwook; Sung, Jong Hwan

    2013-08-15

    Biotransformation in the liver plays an important role in determining the pharmacokinetic profile of drugs and food components. Current in vitro platforms for testing the liver metabolism suffers from the lack of resemblance to the human liver metabolism, mainly due to the lost metabolic activity of cultured hepatocytes and the absence of transport phenomena that occurs in the liver tissue. Here we report a microfluidic device with liver microsome encapsulated in 3-D hydrogel matrix, which can mimic the metabolism reaction and the transport phenomena in the liver. Photopolymerization of poly(ethylene glycol) diacrylate (PEG-DA) allows controlling the mass transfer with matrix sizes, and a gravity-induced passive flow can reproduce the blood flow through the liver. We measured the reaction kinetics of P450 enzymes in the device, and simulated the convection-diffusion-reaction characteristics inside the device with a mathematical model. Combination of mathematical analytical tool and the experimental tool allowed us to analyze and optimize the reaction kinetics inside the microfluidic chip. This novel in vitro platform can serve as a tool for screening the liver metabolism of various compounds. PMID:23830456

  13. Measurement of platelet aggregation functions using whole blood migration ratio in a microfluidic chip.

    PubMed

    Seo, Hong Seog; Choi, Sung Hyuk; Han, Miran; Kim, Kyeong Ah; Cho, Chi Hyun; An, Seong Soo A; Lim, Chae Seung; Shin, Sehyun

    2015-09-25

    Platelets play a major role in maintaining endothelial integrity and hemostasis. Of the various soluble agonists, ADP is an important in vivo stimulus for inducing platelet aggregation. In this study, a simple, rapid, and affordable method was designed for testing bleeding time (BT) and platelet aggregation with a two-channel microfluidic chip. Whole blood migration ratio (MR) from a microchip system was evaluated in comparison to the closure time (CT) from PFA-100 assays (Siemens, Germany) and CD62P expression on platelets. To induce platelet aggregation, a combination of collagen (1.84 mg/ml) and ADP (37.5 mg/ml) were used as agonists. After adding the agonists to samples, whole blood MR from the microchip system was measured. The outcome of the assessment depended on reaction time and agonist concentration. MR of whole blood from the microchip system was significantly correlated with CT from PFA-100 (r = 0.61, p <  0.05, n = 60). In addition, MR was negatively correlated with CD62P expression (r =-0.95, p <  0.05, n = 60). These results suggest that the measurement of MR using agonists is an easy, simple and efficient method for monitoring platelet aggregation in normal and ADP-receptors defective samples, along with the BT test. Thus, usage of the current microfluidic method could expand to diverse applications, including efficacy assessments in platelet therapy. PMID:26444593

  14. Microfluidic devices for cell culture and handling in organ-on-a-chip applications

    NASA Astrophysics Data System (ADS)

    Becker, Holger; Schulz, Ingo; Mosig, Alexander; Jahn, Tobias; Gärtner, Claudia

    2014-03-01

    For many problems in system biology or pharmacology, in-vivo-like models of cell-cell interactions or organ functions are highly sought after. Conventional stationary cell culture in 2D plates quickly reaches its limitations with respect to an in-vivo like expression and function of individual cell types. Microfabrication technologies and microfluidics offer an attractive solution to these problems. The ability to generate flow as well as geometrical conditions for cell culture and manipulation close to the in-vivo situation allows for an improved design of experiments and the modeling of organ-like functionalities. Furthermore, reduced internal volumes lead to a reduction in reagent volumes necessary as well as an increased assay sensitivity. In this paper we present a range of microfluidic devices designed for the co-culturing of a variety of cells. The influence of substrate materials and surface chemistry on the cell morphology and viability for long-term cell culture has been investigated as well as strategies and medium supply for on-chip cell cultivation.

  15. Assessment of mitochondrial membrane potential using an on-chip microelectrode in a microfluidic device

    PubMed Central

    Dávila, Antonio; Wallace, Douglas C.; Burke, Peter

    2010-01-01

    The mitochondrial membrane potential is used to generate and regulate energy in living systems, driving the conversion of ADP to ATP, regulating ion homeostasis, and controlling apoptosis, all central to human health and disease. Therefore, there is a need for tools to study its regulation in a controlled environment for potential clinical and scientific applications. For this aim, an on-chip tetraphenylphosphonium (TPP+) selective microelectrode sensor was constructed in a microfluidic environment. The concentration of isolated mitochondria (Heb7A) used in a membrane potential measurement was 0.3 ng μL−1, four orders of magnitude smaller than the concentration used in conventional assays (3 μg μL−1). In addition, the volume of the chamber (85 μL) is 2 orders of magnitude smaller than traditional experiments. As a demonstration, changes in the membrane potential are clearly measured in response to a barrage of well-known substrates and inhibitors of the electron transport chain. This general approach, which to date has not been demonstrated for study of mitochondrial function and bio-energetics in generally, can be instrumental in advancing the field of mitochondrial research and clinical applications by allowing high throughput studies of the regulation, dynamics, and statistical properties of the mitochondrial membrane potential in response to inhibitors and inducers of apoptosis in a controlled (microfluidic) chemical environment. PMID:20383402

  16. Single Cell Mass Measurement Using Drag Force Inside Lab-on-Chip Microfluidics System.

    PubMed

    Rahman, Md Habibur; Ahmad, Mohd Ridzuan; Takeuchi, Masaru; Nakajima, Masahiro; Hasegawa, Yasuhisa; Fukuda, Toshio

    2015-12-01

    Single cell mass (SCM) is an intrinsic property of single cell, it arouses a great interest among scientists as cell mass depends on the synthesis of proteins, DNA replication, cell wall stiffness, cell cytoplasm density, cell growth, ribosome, and other analogous of organisms. To date, several great strides have been taken to the advancements of SCM measurement techniques. Nevertheless, more works are required to enable the technology to push frontier in deep analysis of SCM measurement, hence to elucidate intracellular properties. In this paper, we present a lab-on-chip microfluidics system for SCM measurement, related with the force required to drag a single cell and Newton's law of motion inside microfluidics channel. Drag force on the cell was generated by a pressure driven syringe micropump and the motion of the cell was measured using optical observation under an inverted microscope. This approach of measuring SCM was calibrated using known mass (77.3 pg) of a polystyrene particle of 5.2 μm diameter. Furthermore, we used Saccharomyces cerevisiae baker's yeast cells of different sizes ([Formula: see text] diameter) for SCM measurement. Mass of 4.4 μm diameter of single yeast cell was measured as 2.12 pg which is in the range of previously reported single yeast cell mass (2-3 pg). In addition, we also studied the relation between SCM and single cell size. Results showed that single yeast cell mass increases exponentially with the increasing of single cell size. PMID:26761952

  17. Glucose microfluidic fuel cell based on silver bimetallic selective catalysts for on-chip applications

    NASA Astrophysics Data System (ADS)

    Cuevas-Muñiz, F. M.; Guerra-Balcázar, M.; Esquivel, J. P.; Sabaté, N.; Arriaga, L. G.; Ledesma-García, J.

    2012-10-01

    A glucose microfluidic fuel cell with outstanding performance at zero flow condition is presented. Polarization tests showed that bimetallic materials based in silver (AuAg/C as anode, PtAg/C as cathode) exhibit tolerance to byproducts and crossover effect. This allowed achieving one of the highest power densities reported for glucose fuel cells, up to a value of 630 μW cm-2 using two separated laminar flows of reactants. Furthermore, the tolerance to crossover effect caused by the selectivity of PtAg/C to oxygen reduction reaction in presence of glucose permitted using a single flow containing a mixture of glucose/oxygen, yielding a performance as high as 270 μW cm-2. Microfluidic fuel cell was further evaluated with a simulated body fluid solution that contained salts commonly present in the human blood plasma, reaching a power of 240 μW cm-2 at zero flow. These results envisage the incorporation of this fuel cell as a portable power source in Lab-on-a-Chip devices without the need of external pumps.

  18. Isolation and Amplification of mRNA within a Simple Microfluidic Lab on a Chip

    PubMed Central

    Reinholt, Sarah J.; Behrent, Arne; Greene, Cassandra; Kalfe, Ayten; Baeumner, Antje J.

    2014-01-01

    The major modules for realizing molecular biological assays in a micro total analysis system (μTAS) were developed for the detection of pathogenic organisms. The specific focus was the isolation and amplification of eukaryotic messenger RNA (mRNA) within a simple, single-channel device for very low RNA concentrations that could then be integrated with detection modules. The hsp70 mRNA from Cryptosporidium parvum was used as a model analyte. Important points of study were surface chemistries within poly(methyl methacrylate) (PMMA) microfluidic channels that enabled specific and sensitive mRNA isolation and amplification reactions for very low mRNA concentrations. Optimal conditions were achieved when the channel surface was carboxylated via UV/ozone treatment followed by the immobilization of polyamidoamine (PAMAM) dendrimers on the surface, thus increasing the immobilization efficiency of the thymidine oligonucleotide, oligo(dT)25, and providing a reliable surface for the amplification reaction, importantly, without the need for blocking agents. Additional chemical modifications of the remaining active surface groups were studied to avoid non-specific capturing of nucleic acids and hindering of the mRNA amplification at low RNA concentrations. Amplification of the mRNA was accomplished using nucleic acid sequence-based amplification (NASBA), an isothermal, primer-dependent technique. Positive controls consisting of previously generated NASBA amplicons could be diluted 1015 fold and still result in successful on-chip re-amplification. Finally, the successful isolation and amplification of mRNA from as few as 30 C. parvum oocysts was demonstrated directly on-chip and compared to bench-top devices. This is the first proof of successful mRNA isolation and NASBA-based amplification of mRNA within a simple microfluidic device in relevant analytical volumes. PMID:24328414

  19. Temperature-controlled MPa-pressure ultrasonic cell manipulation in a microfluidic chip.

    PubMed

    Ohlin, Mathias; Iranmanesh, Ida; Christakou, Athanasia E; Wiklund, Martin

    2015-08-21

    We study the temperature-independent impact on cell viability of relevant physical parameters during long-term, high-acoustic-pressure ultrasonic exposure in a microfluidic chip designed for ultrasonic-standing-wave trapping and aggregation of cells. We use a light-intensity method and 5 μm polymer beads for accurate acoustic pressure calibration before injecting cells into the device, and we monitor the viability of A549 lung cancer cells trapped during one hour in an ultrasonic standing wave with 1 MPa pressure amplitude. The microfluidic chip is actuated by a novel temperature-controlled ultrasonic transducer capable of keeping the temperature stable around 37 °C with an accuracy better than ±0.2 °C, independently on the ultrasonic power and heat produced by the system, thereby decoupling any temperature effect from other relevant effects on cells caused by the high-pressure acoustic field. We demonstrate that frequency-modulated ultrasonic actuation can produce acoustic pressures of equally high magnitudes as with single-frequency actuation, and we show that A549 lung cancer cells can be exposed to 1 MPa standing-wave acoustic pressure amplitudes for one hour without compromising cell viability. At this pressure level, we also measure the acoustic streaming induced around the trapped cell aggregate, and conclude that cell viability is not affected by streaming velocities of the order of 100 μm s(-1). Our results are important when implementing acoustophoresis methods in various clinical and biomedical applications. PMID:26156858

  20. An in situ Raman spectroscopy-based microfluidic "lab-on-a-chip" platform for non-destructive and continuous characterization of Pseudomonas aeruginosa biofilms.

    PubMed

    Feng, Jinsong; de la Fuente-Núñez, César; Trimble, Michael J; Xu, Jie; Hancock, Robert E W; Lu, Xiaonan

    2015-05-28

    Pseudomonas aeruginosa biofilm was cultivated and characterized in a microfluidic "lab-on-a-chip" platform coupled with confocal Raman microscopy in a non-destructive manner. Biofilm formation could be quantified by this label-free platform and correlated well with confocal laser scanning microscopy. This Raman-microfluidic platform could also discriminate biofilms at different developmental stages. PMID:25929246

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

    NASA Technical Reports Server (NTRS)

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

    2013-01-01

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

  2. 3D microfluidic chips with integrated functional microelements fabricated by a femtosecond laser for studying the gliding mechanism of cyanobacteria.

    PubMed

    Hanada, Yasutaka; Sugioka, Koji; Shihira-Ishikawa, Ikuko; Kawano, Hiroyuki; Miyawaki, Atsushi; Midorikawa, Katsumi

    2011-06-21

    Phormidium, a genus of filamentous cyanobacteria, forms endosymbiotic associations with seedling roots that accelerate the growth of the vegetable seedlings. Understanding the gliding mechanism of Phormidium will facilitate improved formation of this association and increased vegetable production. To observe the gliding movements, we fabricated various microfluidic chips termed nanoaquariums using a femtosecond (fs) laser. Direct fs laser writing, followed by annealing and successive wet etching in dilute hydrofluoric acid solution, can easily produce three-dimensional (3D) microfluidics with different structures embedded in a photostructurable glass. Using the fs laser, optical waveguides and filters were integrated with the microfluidic structures in the microchips, allowing the gliding mechanism to be more easily clarified. Using this apparatus, we found that CO(2) secreted from the seedling root attracts Phormidium in the presence of light, and determined the light intensity and specific wavelength necessary for gliding. PMID:21562650

  3. Processing window for femtosecond laser microsurgery and fluorescence imaging of an arterial tissue hosted in a microfluidic chip

    NASA Astrophysics Data System (ADS)

    Karimelahi, Samira; Li, Jianzhao; Herman, Peter R.

    2016-02-01

    We study the exposure limitations of femtosecond laser microsurgery and multiphoton imaging in a microfluidic chip environment, assessing damage thresholds at various interfaces as well as interference from bubble formation in the hosting solution. Both heat accumulation and incubation effects from multipulse laser exposures at 1-MHz repetition rate were evaluated. For demonstration, three microsurgery approaches of laser scribing, percussion drilling and trepanning were applied to arterial walls loaded in vitro in a lab-on-a-chip device. We report that deleterious effects from interface damage and microbubble formation can be avoided to offer laser processing windows for damage-free fluorescence imaging and precise microsurgery of live tissue hosted inside small microfluidic chambers.

  4. Online multi-channel microfluidic chip-mass spectrometry and its application for quantifying noncovalent protein-protein interactions.

    PubMed

    Liu, Wu; Chen, Qiushui; Lin, Xuexia; Lin, Jin-Ming

    2015-03-01

    To establish an automatic and online microfluidic chip-mass spectrometry (chip-MS) system, a device was designed and fabricated for microsampling by a hybrid capillary. The movement of the capillary was programmed by a computer to aspirate samples from different microfluidic channels in the form of microdroplets (typically tens of nanoliters in volume), which were separated by air plugs. The droplets were then directly analyzed by MS via paper spray ionization without any pretreatment. The feasibility and performance were demonstrated by a concentration gradient experiment. Furthermore, after eliminating the effect of nonuniform response factors by an internal standard method, determination of the association constant within a noncovalent protein-protein complex was successfully accomplished with the MS-based titration indicating the versatility and the potential of this novel platform for widespread applications. PMID:25597452

  5. DNA-library assembly programmed by on-demand nano-liter droplets from a custom microfluidic chip.

    PubMed

    Tangen, Uwe; Minero, Gabriel Antonio S; Sharma, Abhishek; Wagler, Patrick F; Cohen, Rafael; Raz, Ofir; Marx, Tzipy; Ben-Yehezkel, Tuval; McCaskill, John S

    2015-07-01

    Nanoscale synthetic biology can benefit from programmable nanoliter-scale processing of DNA in microfluidic chips if they are interfaced effectively to biochemical arrays such as microwell plates. Whereas active microvalve chips require complex fabrication and operation, we show here how a passive and readily fabricated microchip can be employed for customizable nanoliter scale pipetting and reaction control involving DNA. This recently developed passive microfluidic device, supporting nanoliter scale combinatorial droplet generation and mixing, is here used to generate a DNA test library with one member per droplet exported to addressed locations on microwell plates. Standard DNA assembly techniques, such as Gibson assembly, compatible with isothermal on-chip operation, are employed and checked using off-chip PCR and assembly PCR. The control of output droplet sequences and mixing performance was verified using dyes and fluorescently labeled DNA solutions, both on-chip and in external capillary channels. Gel electrophoresis of products and DNA sequencing were employed to further verify controlled combination and functional enzymatic assembly. The scalability of the results to larger DNA libraries is also addressed by combinatorial input expansion using sequential injection plugs from a multiwell plate. Hence, the paper establishes a proof of principle of the production of functional combinatorial mixtures at the nanoliter scale for one sequence per well DNA libraries. PMID:26221198

  6. DNA-library assembly programmed by on-demand nano-liter droplets from a custom microfluidic chip

    PubMed Central

    Tangen, Uwe; Minero, Gabriel Antonio S.; Sharma, Abhishek; Wagler, Patrick F.; Cohen, Rafael; Raz, Ofir; Marx, Tzipy; Ben-Yehezkel, Tuval; McCaskill, John S.

    2015-01-01

    Nanoscale synthetic biology can benefit from programmable nanoliter-scale processing of DNA in microfluidic chips if they are interfaced effectively to biochemical arrays such as microwell plates. Whereas active microvalve chips require complex fabrication and operation, we show here how a passive and readily fabricated microchip can be employed for customizable nanoliter scale pipetting and reaction control involving DNA. This recently developed passive microfluidic device, supporting nanoliter scale combinatorial droplet generation and mixing, is here used to generate a DNA test library with one member per droplet exported to addressed locations on microwell plates. Standard DNA assembly techniques, such as Gibson assembly, compatible with isothermal on-chip operation, are employed and checked using off-chip PCR and assembly PCR. The control of output droplet sequences and mixing performance was verified using dyes and fluorescently labeled DNA solutions, both on-chip and in external capillary channels. Gel electrophoresis of products and DNA sequencing were employed to further verify controlled combination and functional enzymatic assembly. The scalability of the results to larger DNA libraries is also addressed by combinatorial input expansion using sequential injection plugs from a multiwell plate. Hence, the paper establishes a proof of principle of the production of functional combinatorial mixtures at the nanoliter scale for one sequence per well DNA libraries. PMID:26221198

  7. Integration of micro-optics and microfluidics in a glass chip by fs-laser for optofluidic applications

    NASA Astrophysics Data System (ADS)

    Osellame, Roberto; Martinez, Rebeca; Laporta, Paolo; Ramponi, Roberta; Cerullo, Giulio

    2009-02-01

    A lab-on-a-chip (LOC) is a device that incorporates in a single substrate the functionalities of a biological laboratory, i.e. a network of fluidic channels, reservoirs, valves, pumps and sensors, all with micrometer dimensions. Its main advantages are the possibility of working with small samples quantities (from nano- to picoliters), high sensitivity, speed of analysis and the possibility of measurement automation and standardization. They are becoming the most powerful tools of analytical chemistry with a broad application in life sciences, biotechnology and drug development. The next technological challenge of LOCs is direct on-chip integration of photonic functionalities for sensing of biomolecules flowing in the microchannels. Ultrafast laser processing of the bulk of a dielectric material is a very flexible and simple method to produce photonic devices inside microfluidic chips for capillary electrophoresis (CE) or chemical microreactors. By taking advantage of the unique three-dimensional capabilities of this fabrication technique, more complex functionalities, such as splitters or Mach-Zehnder interferometers, can be implemented. In this work we report on the use of femtosecond laser pulses to fabricate photonic devices (as waveguides, splitters and interferometers) inside commercial CE chips, without affecting the manufacturing procedure of the microfluidic part of the device. The fabrication of single waveguides intersecting the channels allows one to perform absorption or Laser Induced Fluorescence (LIF) sensing of the molecules separated inside the microchannels. Waveguide splitters are used for multipoint excitation of the microfluidic channel for parallel or higher sensitivity measurements. Finally, Mach-Zehnder interferometers are used for label-free sensing of the samples flowing in the microfluidic channels by means of refractive index changes detection.

  8. A lab-on-a-chip system for the development of complex assays using modular microfluidic components

    NASA Astrophysics Data System (ADS)

    Hlawatsch, Nadine; Klemm, Richard; Carstens, Cornelia; Brandst"tter, Thomas; Becker, Holger; Elbracht, Rudi; Gärtner, Claudia

    2012-03-01

    For complex biological or diagnostic assays, the development of an integrated microfluidic device can be difficult and error-prone. For this reason, a modular approach, using individual microfluidic functional modules for the different process steps, can be advantageous. However often the interconnection of the modules proves to be tedious and the peripheral instrumentation to drive the various modules is cumbersome and of large size. For this reason, we have developed an integrated instrument platform which has generic functionalities such as valves and pumps, heating zones for continuous-flow PCR, moveable magnets for bead-based assays and an optical detection unit build into the instrument. The instrument holds a titerplate-sized carrier in which up to four microscopy-slide sized microfluidic modules can be clipped in. This allows for developing and optimizing individual assay steps without the need to modify the instrument or generate a completely new microfluidic cartridge. As a proof-of-concept, the automated sample processing of liquor or blood culture in microfluidic structures for detection of currently occuring Neisseria meningitidis strains was carried out. This assay involves the extraction of bacterial DNA, the fluorescent labeling, amplification using PCR as well as the hybridization of the DNA molecules in three-dimensional capture sites spotted into a microchannel. To define the assay sensitivity, chip modules were tested with bacteria spiked samples of different origins and results were controlled by conventional techniques. For liquor or blood culture, the presence of 200 bacteria was detected within 1 hour.

  9. Microfluidic and lab-on-a-chip preparation routes for organic nanoparticles and vesicular systems for nanomedicine applications.

    PubMed

    Capretto, Lorenzo; Carugo, Dario; Mazzitelli, Stefania; Nastruzzi, Claudio; Zhang, Xunli

    2013-11-01

    In recent years, advancements in the fields of microfluidic and lab-on-a-chip technologies have provided unique opportunities for the implementation of nanomaterial production processes owing to the miniaturisation of the fluidic environment. It has been demonstrated that microfluidic reactors offer a range of advantages compared to conventional batch reactors, including improved controllability and uniformity of nanomaterial characteristics. In addition, the fast mixing achieved within microchannels, and the predictability of the laminar flow conditions, can be leveraged to investigate the nanomaterial formation dynamics. In this article recent developments in the field of microfluidic production of nanomaterials for drug delivery applications are reviewed. The features that make microfluidic reactors a suitable technological platform are discussed in terms of controllability of nanomaterials production. An overview of the various strategies developed for the production of organic nanoparticles and colloidal assemblies is presented, focusing on those nanomaterials that could have an impact on nanomedicine field such as drug nanoparticles, polymeric micelles, liposomes, polymersomes, polyplexes and hybrid nanoparticles. The effect of microfluidic environment on nanomaterials formation dynamics, as well as the use of microdevices as tools for nanomaterial investigation is also discussed. PMID:23933616

  10. Basic capillary microfluidic chip and highly sensitive optical detector for point of care application

    NASA Astrophysics Data System (ADS)

    Yao, Mingjin

    A cost-effective and highly sensitive portable diagnostic device is needed to enable much more widespread monitoring of health conditions in disease prevention, detection, and control. Miniaturized and easy-to-operate devices can reduce the inherent costs and inefficiencies associated with healthcare testing in central laboratories. Hence, clinicians are beginning to use point of care (POC) testing and flexible clinical chemistry testing devices which are beneficial for the patient. In our work, a low-cost and simple autonomous microfluidic device for biochemical detection was developed. The pumpless capillary system with capillary stop valves and trigger valves is fabricated on a silicon (Si) wafer and then bonded with the modified polydimethylsiloxane (PDMS) cover. The key point of this study is the change of the surface contact angle of the PDMS to achieve the functionalities such as timing features (capillary-driven stop valve) and basic logical functions (trigger valves). The polydimethylsiloxane-ethylene oxide polymer (PDMS-b-PEO) is utilized as a surfactant additive to make the PDMS hydrophilic. The contact angle of the modified PDMS can be adjusted from 80.9° to 21.5° with different mixing ratios. The contact angles of PEO-PDMS accepted in this work are from 80.9° to 58.5° to bring the capillary channel and valve into effect. This autonomous capillary-driven device with good microfluidic flow manipulation can be widely applied to a number of microfluidic devices and pumpless fluidic actuation mechanisms, which is suitable for cost-effective diagnostic tools in the biomedical analysis and POC testing applications. Another obstacle for miniaturization of the bio-detection system is the optical detector. We developed a novel, highly sensitive and miniaturized detector. It integrates a light source--light emitting diode (LED), all necessary optical components, and a photodiode with preamplifier into one package about 2 cm x 2 cm x 2 cm, especially for the

  11. Beating heart on a chip: a novel microfluidic platform to generate functional 3D cardiac microtissues.

    PubMed

    Marsano, Anna; Conficconi, Chiara; Lemme, Marta; Occhetta, Paola; Gaudiello, Emanuele; Votta, Emiliano; Cerino, Giulia; Redaelli, Alberto; Rasponi, Marco

    2016-02-01

    In the past few years, microfluidic-based technology has developed microscale models recapitulating key physical and biological cues typical of the native myocardium. However, the application of controlled physiological uniaxial cyclic strains on a defined three-dimension cellular environment is not yet possible. Two-dimension mechanical stimulation was particularly investigated, neglecting the complex three-dimensional cell-cell and cell-matrix interactions. For this purpose, we developed a heart-on-a-chip platform, which recapitulates the physiologic mechanical environment experienced by cells in the native myocardium. The device includes an array of hanging posts to confine cell-laden gels, and a pneumatic actuation system to induce homogeneous uniaxial cyclic strains to the 3D cell constructs during culture. The device was used to generate mature and highly functional micro-engineered cardiac tissues (μECTs), from both neonatal rat and human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CM), strongly suggesting the robustness of our engineered cardiac micro-niche. Our results demonstrated that the cyclic strain was effectively highly uniaxial and uniformly transferred to cells in culture. As compared to control, stimulated μECTs showed superior cardiac differentiation, as well as electrical and mechanical coupling, owing to a remarkable increase in junction complexes. Mechanical stimulation also promoted early spontaneous synchronous beating and better contractile capability in response to electric pacing. Pacing analyses of hiPSC-CM constructs upon controlled administration of isoprenaline showed further promising applications of our platform in drug discovery, delivery and toxicology fields. The proposed heart-on-a-chip device represents a relevant step forward in the field, providing a standard functional three-dimensional cardiac model to possibly predict signs of hypertrophic changes in cardiac phenotype by mechanical and biochemical co

  12. Gradient Static-Strain Stimulation in a Microfluidic Chip for 3D Cellular Alignment

    PubMed Central

    Hsieh, Hsin-Yi; Camci-Unal, Gulden; Huang, Tsu-Wei; Liao, Ronglih; Chen, Tsung-Ju; Paul, Arghya; Tseng, Fan-Gang; Khademhosseini, Ali

    2014-01-01

    Cell alignment is a critical factor to govern cellular behavior and function for various tissue engineering applications ranging from cardiac to neural regeneration. In addition to physical geometry, strain is a crucial parameter to manipulate cellular alignment for functional tissue formation. In this paper, we introduce a simple approach to generate a range of gradient static strains without external mechanical control for the stimulation of cellular behavior within 3D biomimetic hydrogel microenvironments. A glass-supported microfluidic chip with a convex flexible polydimethylsiloxane (PDMS) membrane on the top was employed for loading the cells suspended in a prepolymer solution. Following UV crosslinking through a photomask with a concentric circular pattern, the cell-laden hydrogels were formed in a height gradient from the center (maximum) to the boundary (minimum). When the convex PDMS membrane retracted back to a flat surface, it applied compressive gradient forces on the cell-laden hydrogels. The concentric circular hydrogel patterns confined the direction of hydrogel elongation, and the compressive strain on the hydrogel therefore resulted in elongation stretch in the radial direction to guide cell alignment. NIH3T3 cells were cultured in the chip for 3 days with compressive strains that varied from ~65% (center) to ~15% (boundary) on hydrogels. We found that the hydrogel geometry dominated the cell alignment near the outside boundary, where cells aligned along the circular direction, and the compressive strain dominated the cell alignment near the center, where cells aligned radially. This study developed a new and simple approach to facilitate cellular alignment based on hydrogel geometry and strain stimulation for tissue engineering applications. This platform offers unique advantages and is significantly different than the existing approaches owing to the fact that gradient generation was accomplished in a miniature device without using an external

  13. Chemical stimulation of the Arabidopsis thaliana root using multi-laminar flow on a microfluidic chip.

    PubMed

    Meier, Matthias; Lucchetta, Elena M; Ismagilov, Rustem F

    2010-08-21

    In this article, we developed a "plant on a chip" microfluidic platform that can control the local chemical environment around live roots of Arabidopsis thaliana with high spatial resolution using multi-laminar flow. We characterized the flow profile around the Arabidopsis root, and verified that the shear forces within the device ( approximately 10 dyne cm(-2)) did not impede growth of the roots. Our platform was able to deliver stimuli to the root at a spatial resolution of 10-800 microm. Further, the platform was validated by exposing desired regions of the root with a synthetic auxin derivative, 2,4-dichlorophenoxyacetic acid (2,4-D), and its inhibitor N-1-naphthylphthalamic acid (NPA). The response to the stimuli was observed using a DR5::GFP Arabidopsis line, where GFP expression is coupled to the auxin response regulator DR5. GFP expression in the root matched the position of the flow-focused stream containing 2,4-D. When the regions around the 2,4-D stimulus were exposed to the auxin transport inhibitor NPA, the active and passive transport mechanisms of auxin could be differentiated, as NPA blocks active cell-to-cell transport of auxin. Finally, we demonstrated that local 2,4-D stimulation in a approximately 10 microm root segment enhanced morphological changes such as epidermal hair growth. These experiments were proof-of-concept and agreed with the results expected based on known root biology, demonstrating that this "root on a chip" platform can be used to test how root development is affected by any chemical component of interest, including nitrogen, phosphate, salts, and other plant hormones. PMID:20544086

  14. Incorporation of electrospun nanofibrous PVDF membranes into a microfluidic chip assembled by PDMS and scotch tape for immunoassays.

    PubMed

    Liu, Yingyi; Yang, Dayong; Yu, Tao; Jiang, Xingyu

    2009-09-01

    This paper demonstrates a microfluidic chip for multiple immunoassays on electrospun (ES) nanofibrous membranes made of PVDF. This microchip enables the detection of multiple pairs of protein-protein interactions in one experiment by crossing parallel arrays of microchannels. This chip uses ESPVDF membrane with high specific surface area as the substrate to adsorb protein for immobilized immunoassays so that increased levels of protein adsorption may lower the LOD in immunoassays. We employ a simple and effective method for chip assembly by scotch tape to incorporate the ESPVDF membrane into the microchip. We believe that the present work will facilitate the development of methods for the on-site diagnosis of diseases whose detection is based on antigen-antibody recognition, and improve the efficiencies of certain experiments that need to identify tens to hundreds of protein-protein interactions with relatively low cost in the future. PMID:19722208

  15. Investigation of Tumor Cell Behaviors on a Vascular Microenvironment-Mimicking Microfluidic Chip.

    PubMed

    Huang, Rong; Zheng, Wenfu; Liu, Wenwen; Zhang, Wei; Long, Yunze; Jiang, Xingyu

    2015-01-01

    The extravasation of tumor cells is a key event in tumor metastasis. However, the mechanism underlying tumor cell extravasation remains unknown, mainly hindered by obstacles from the lack of complexity of biological tissues in conventional cell culture, and the costliness and ethical issues of in vivo experiments. Thus, a cheap, time and labor saving, and most of all, vascular microenvironment-mimicking research model is desirable. Herein, we report a microfluidic chip-based tumor extravasation research model which is capable of simultaneously simulating both mechanical and biochemical microenvironments of human vascular systems and analyzing their synergistic effects on the tumor extravasation. Under different mechanical conditions of the vascular system, the tumor cells (HeLa cells) had the highest viability and adhesion activity in the microenvironment of the capillary. The integrity of endothelial cells (ECs) monolayer was destroyed by tumor necrosis factor-α (TNF-α) in a hemodynamic background, which facilitated the tumor cell adhesion, this situation was recovered by the administration of platinum nanoparticles (Pt-NPs). This model bridges the gap between cell culture and animal experiments and is a promising platform for studying tumor behaviors in the vascular system. PMID:26631692

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

    PubMed Central

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

    2012-01-01

    A rapid and simple technique is proposed for methanol concentration detection using a PMMA (Polymethyl-Methacrylate) microfluidic chip patterned using a commercially available CO2 laser scriber. In the proposed device, methanol and methanol oxidase (MOX) are injected into a three-dimensional circular chamber and are mixed via a vortex stirring effect. The mixture is heated to prompt the formation of formaldehyde and is flowed into a rectangular chamber, to which fuchsin-sulphurous acid is then added. Finally, the microchip is transferred to a UV spectrophotometer for methanol detection purposes. The experimental results show that a correlation coefficient of R2 = 0.9940 is obtained when plotting the optical density against the methanol concentration for samples and an accuracy as high as 93.1% are compared with the determined by the high quality gas chromatography with concentrations in the range of 2 ∼ 100 ppm. The methanol concentrations of four commercial red wines are successfully detected using the developed device. Overall, the results show that the proposed device provides a rapid and accurate means of detecting the methanol concentration for a variety of applications in the alcoholic beverage inspection and control field. PMID:23940501

  17. Construction and operation of a microrobot based on magnetotactic bacteria in a microfluidic chip

    PubMed Central

    Ma, Qiufeng; Chen, Changyou; Wei, Shufeng; Chen, Chuanfang; Wu, Long-Fei; Song, Tao

    2012-01-01

    Magnetotactic bacteria (MTB) are capable of swimming along magnetic field lines. This unique feature renders them suitable in the development of magnetic-guided, auto-propelled microrobots to serve in target molecule separation and detection, drug delivery, or target cell screening in a microfluidic chip. The biotechnology to couple these bacteria with functional loads to form microrobots is the critical point in its application. Although an immunoreaction approach to attach functional loads to intact MTB was suggested, details on its realization were hardly mentioned. In the current paper, MTB-microrobots were constructed by attaching 2 μm diameter microbeads to marine magnetotactic ovoid MO-1 cells through immunoreactions. These microrobots were controlled using a special control and tracking system. Experimental results prove that the attachment efficiency can be improved to ∼30% via an immunoreaction. The motility of the bacteria attached with different number of loads was also assessed. The results show that MTB can transport one load at a velocity of ∼21 μm/s and still move and survive for over 30 min. The control and tracking system is fully capable of directing and monitoring the movement of the MTB-microrobots. The rotating magnetic fields can stop the microrobots by trapping them as they swim within a circular field with a controllable size. The system has potential use in chemical analyses and medical diagnoses using biochips as well as in nano/microscale transport. PMID:22655018

  18. On-chip characterization of cryoprotective agent mixtures using an EWOD-based digital microfluidic device.

    PubMed

    Park, Sinwook; Wijethunga, Pavithra A L; Moon, Hyejin; Han, Bumsoo

    2011-07-01

    For tissue engineering and regenerative medicine, cryopreservation, a technique for preserving biomaterials in the frozen state with cryoprotective agents (CPAs), is critically important for preserving engineered tissues (ETs) as well as cells necessary to create ETs. As more diverse ETs are produced using various cell types, CPAs and corresponding freeze/thaw (F/T) protocols need to be developed cell/tissue-type specifically. This is because CPAs and F/T protocols that have been successful for one cell/tissue type have proven to be difficult to adapt to other cell/tissue types. The most critical barrier to address this challenge is the inability to screen and identify CPA or CPA mixtures efficiently. In this paper, we developed an "electro-wetting-on-dielectic" (EWOD) based digital microfluidic platform to characterize and screen CPA mixtures cell-type specifically. The feasibility of the EWOD platform was demonstrated by characterizing and optimizing a mixture of dimethlysulfoxide (DMSO) and PBS for human breast cancer cell line as model CPA mixture and cell line. The developed platform multiplexed droplets of DMSO and PBS to create an array of DMSO-PBS mixtures, and mapped the phase change diagram of the mixture. After loading cell suspensions on the platform, the mixture was further screened on-chip for toxicity and cryoprotection. The results were discussed to illustrate the capabilities and limitations of the EWOD platform for cell and tissue-type specific optimization of CPA mixtures and F/T protocols. PMID:21603697

  19. On-chip characterization of cryoprotective agent mixtures using an EWOD-based digital microfluidic device

    PubMed Central

    Park, Sinwook; Wijethunga, Pavithra A. L.; Moon, Hyejin; Han, Bumsoo

    2011-01-01

    For tissue engineering and regenerative medicine, cryopreservation, a technique for preserving biomaterials in the frozen state with cryoprotective agents (CPAs), is critically important for preserving engineered tissues (ETs) as well as cells necessary to create ETs. As more diverse ETs are produced using various cell types, CPAs and corresponding freeze/thaw (F/T) protocols need to be developed cell/tissue-type specifically. This is because CPAs and F/T protocols that have been successful for one cell/tissue type have proven to be difficult to adapt to other cell/tissue types. The most critical barrier to address this challenge is the inability to screen and identify CPA or CPA mixtures efficiently. In this paper, we developed an "electro-wetting-on-dielectic" (EWOD) based digital microfluidic platform to characterize and screen CPA mixtures cell-type specifically. The feasibility of the EWOD platform was demonstrated by characterizing and optimizing a mixture of dimethlysulfoxide (DMSO) and PBS for human breast cancer cell line as model CPA mixture and cell line. The developed platform multiplexed droplets of DMSO and PBS to create an array of DMSO-PBS mixtures, and mapped the phase change diagram of the mixture. After loading cell suspensions on the platform, the mixture was further screened on-chip for toxicity and cryoproection. The results were discussed to illustrate the capabilities and limitations of the EWOD platform for cell and tissue-type specific optimization of CPA mixtures and F/T protocols. PMID:21603697

  20. Investigation of Tumor Cell Behaviors on a Vascular Microenvironment-Mimicking Microfluidic Chip

    PubMed Central

    Huang, Rong; Zheng, Wenfu; Liu, Wenwen; Zhang, Wei; Long, Yunze; Jiang, Xingyu

    2015-01-01

    The extravasation of tumor cells is a key event in tumor metastasis. However, the mechanism underlying tumor cell extravasation remains unknown, mainly hindered by obstacles from the lack of complexity of biological tissues in conventional cell culture, and the costliness and ethical issues of in vivo experiments. Thus, a cheap, time and labor saving, and most of all, vascular microenvironment-mimicking research model is desirable. Herein, we report a microfluidic chip-based tumor extravasation research model which is capable of simultaneously simulating both mechanical and biochemical microenvironments of human vascular systems and analyzing their synergistic effects on the tumor extravasation. Under different mechanical conditions of the vascular system, the tumor cells (HeLa cells) had the highest viability and adhesion activity in the microenvironment of the capillary. The integrity of endothelial cells (ECs) monolayer was destroyed by tumor necrosis factor-α (TNF-α) in a hemodynamic background, which facilitated the tumor cell adhesion, this situation was recovered by the administration of platinum nanoparticles (Pt-NPs). This model bridges the gap between cell culture and animal experiments and is a promising platform for studying tumor behaviors in the vascular system. PMID:26631692

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

    PubMed

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

    2015-06-21

    Successful diagnosis and treatment of many diseases depends on the availability of sensitive, reliable and low cost tools for the detection of the biomarkers associated with the diseases. Simple methods that use non-invasive biological samples are especially suitable for the deployment in the clinical environment. In this paper we demonstrate the application of a method that employs a capped gold nanoslit surface plasmon resonance (SPR) sensor and a microfluidic chip for the detection of a urinary nucleic acid biomarker in clinical samples. This method detects low concentrations of the biomarker in a relatively large volume (∼1 mL) of the sample. The method utilizes magnetic nanoparticles (MNPs) for the isolation of target molecules and signal enhancement in conjunction with surface plasmon resonance (SPR) on capped gold nanoslits. The ability of the method to detect urinary miRNA-16-5p in AKI patients was tested and the result was compared with the data obtained with the polymerase chain reaction (PCR). miRNA-16-5p has been found to be a specific and noninvasive biomarker for acute kidney injury (AKI). Our method allows the detection of the biomarker in the urine of AKI patients without amplification and labeling of the target molecules. PMID:25891475

  2. Optimised production of multifunctional microfibres by microfluidic chip technology for tissue engineering applications.

    PubMed

    Mazzitelli, Stefania; Capretto, Lorenzo; Carugo, Dario; Zhang, Xunli; Piva, Roberta; Nastruzzi, Claudio

    2011-05-21

    This paper describes a method for the production of alginate microfibres using glass-based microfluidic chips fabricated by a photolithography-wet etching procedure. The main focus of the work is the fabrication of a cell containing multifunctional microfibres which have great potential for applications in drug release formulations and tissue engineering scaffolds (to guide the regeneration of tissues in predefined sizes and shapes) providing cell structural support and immunoisolation. The key parameters, which critically influence the formation of microfibres and their geometries, were identified by a classical intuitive approach COST (Changing One Separate factor a Time). In particular, their effects on the microfibre diameter were investigated, which are directly associated with their functionalities relating to the implantation site, the nutrient availability and diffusion/transport of oxygen, essential nutrients, growth factors, metabolic waste and secretory products. The interplay between the alginate solution concentration, pumping rate and gelling bath concentration in controlling the diameter of the produced microfibres was investigated with a statistical approach by means of a "design of the experiments" (DoEs) optimization and screening. Finally, the processing impacts on cell viability, the cellular effect of wall thickness consistency and the spatial distribution of cells within the alginate microfibre were examined. We provide an approach for the production of alginate microfibres with controlled shape and content, which could be further developed for scaling up and working towards FDA approval. PMID:21472178

  3. Development of micropump-actuated negative pressure pinched injection for parallel electrophoresis on array microfluidic chip.

    PubMed

    Li, Bowei; Jiang, Lei; Xie, Hua; Gao, Yan; Qin, Jianhua; Lin, Bingcheng

    2009-09-01

    A micropump-actuated negative pressure pinched injection method is developed for parallel electrophoresis on a multi-channel LIF detection system. The system has a home-made device that could individually control 16-port solenoid valves and a high-voltage power supply. The laser beam is excitated and distributes to the array separation channels for detection. The hybrid Glass-PDMS microfluidic chip comprises two common reservoirs, four separation channels coupled to their respective pneumatic micropumps and two reference channels. Due to use of pressure as a driving force, the proposed method has no sample bias effect for separation. There is only one high-voltage supply needed for separation without relying on the number of channels, which is significant for high-throughput analysis, and the time for sample loading is shortened to 1 s. In addition, the integrated micropumps can provide the versatile interface for coupling with other function units to satisfy the complicated demands. The performance is verified by separation of DNA marker and Hepatitis B virus DNA samples. And this method is also expected to show the potential throughput for the DNA analysis in the field of disease diagnosis. PMID:19681052

  4. Chitosan microgels obtained by on-chip crosslinking reaction employing a microfluidic device

    NASA Astrophysics Data System (ADS)

    Zamora-Mora, Vanessa; Velasco, Diego; Hernández, Rebeca; Mijangos, Carmen

    2014-12-01

    In the present work, we report on the preparation of microgels of chitosan crosslinked with sodium tripolyphosphate (TPP) employing the microfluidics technique (MF). To achieve this, several flow focusing geometries were designed and tested. As a first step, a two-inlet flow focusing geometry was employed to emulsify chitosan and the crosslinking reaction was carried out offchip. This procedure did not allow separating the resulting chitosan microgels due to an incomplete crosslinking reaction. A crosslinking reaction on-chip was studied as an alternative. A four-inlet flow focusing geometrywas designed in which three dispersed phases, chitosan 0.25% (w/v), TPP 0.05% (w/v) and acetic acid 1% (v/v) and an continuous phase mineral oil + Span 80 (3% w/v) were employed. The flow rates for the continuous phase were varied from 6.7 to 11.7 μL/min and chitosan microgels were successfully obtained with average diameters from 68 to 42 μm. The average size of the microgels outside the MF device decreased up to ~21% with respect to their size inside the MF device due to partial expulsion of water from the microgels when complete gelation occurred.

  5. A microfluidic reactor for rapid, low-pressure proteolysis with on-chip electrospray ionization.

    PubMed

    Liuni, Peter; Rob, Tamanna; Wilson, Derek J

    2010-02-01

    A microfluidic reactor that enables rapid digestion of proteins prior to on-line analysis by electrospray ionization mass spectrometry (ESI-MS) is introduced. The device incorporates a wide (1.5 cm), shallow (10 microm) reactor 'well' that is functionalized with pepsin-agarose, a design that facilitates low-pressure operation and high clogging resistance. Electrospray ionization is carried out directly from a short metal capillary integrated into the chip outlet. Fabrication, involving laser ablation of polymethyl methacrylate (PMMA), is exceedingly straightforward and inexpensive. High sequence coverage spectra of myoglobin (Mb), ubiquitin (Ub) and bovine serum albumin (BSA) digests were obtained after <4 s of residence time in the reactor. Stress testing showed little loss of performance over approximately 2 h continuous use at high flow rates (30 microL/min). The device provides a convenient platform for a range of applications in proteomics and structural biology, i.e. to enable high-throughput workflows or to limit back-exchange in spatially resolved hydrogen/deuterium exchange (HDX) experiments. PMID:20049884

  6. Isolation of motile spermatozoa with a microfluidic chip having a surface-modified microchannel.

    PubMed

    Huang, Hong-Yuan; Wu, Tsung-Lin; Huang, Hung-Ru; Li, Chin-Jung; Fu, Hui-Ting; Soong, Yung-Kuei; Lee, Ming-Yih; Yao, Da-Jeng

    2014-02-01

    Conventional methods to prepare sperm have been amenable to the investigation of outcomes such as rates of recovery and conventional semen parameters. The standard preparation of sperm for assisted reproduction is criticized for its centrifugation steps, which might either recover motile sperm in variable proportions or increase the probability of damage to sperm DNA. An microfluidic system was designed to separate motile sperm according to a design whereby nonmotile spermatozoa and debris flow along their initial streamlines and exit through one outlet-up, whereas motile spermatozoa have an opportunity to swim into a parallel stream and to exit through a separate outlet-down. This chip was fabricated by microelectromechanical systems technology with polydimethylsiloxane molding. The hydrophilic surface, coated with poly (ethanediol) methyl ether methacrylate, exhibits enduring stability maintained for the microchannel. Microscopic examination and fluorescent images showed that the motility of sperm varied with the laminar streams. To confirm the sorting, we identified and quantified the proportions of live and dead sperm before and after sorting with flow cytometric analysis. The results on the viability of a sample demonstrated the increased quality of sperm after sorting and collection in the outlet reservoir. The counted ratio of live sperm revealed the quantity and efficiency of the sorted sperm. PMID:23603751

  7. NeuroChip: A Microfluidic Electrophysiological Device for Genetic and Chemical Biology Screening of Caenorhabditis elegans Adult and Larvae

    PubMed Central

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

    2013-01-01

    Genetic and chemical biology screens of C. elegans have been of enormous benefit in providing fundamental insight into neural function and neuroactive drugs. Recently the exploitation of microfluidic devices has added greater power to this experimental approach providing more discrete and higher throughput phenotypic analysis of neural systems. Here we make a significant addition to this repertoire through the design of a semi-automated microfluidic device, NeuroChip, which has been optimised for selecting worms based on the electrophysiological features of the pharyngeal neural network. We demonstrate this device has the capability to sort mutant from wild-type worms based on high definition extracellular electrophysiological recordings. NeuroChip resolves discrete differences in excitatory, inhibitory and neuromodulatory components of the neural network from individual animals. Worms may be fed into the device consecutively from a reservoir and recovered unharmed. It combines microfluidics with integrated electrode recording for sequential trapping, restraining, recording, releasing and recovering of C. elegans. Thus mutant worms may be selected, recovered and propagated enabling mutagenesis screens based on an electrophysiological phenotype. Drugs may be rapidly applied during the recording thus permitting compound screening. For toxicology, this analysis can provide a precise description of sub-lethal effects on neural function. The chamber has been modified to accommodate L2 larval stages showing applicability for small size nematodes including parasitic species which otherwise are not tractable to this experimental approach. We also combine NeuroChip with optogenetics for targeted interrogation of the function of the neural circuit. NeuroChip thus adds a new tool for exploitation of C. elegans and has applications in neurogenetics, drug discovery and neurotoxicology. PMID:23717588

  8. A rapid and sensitive method for hydroxyl radical detection on a microfluidic chip using an N-doped porous carbon nanofiber modified pencil graphite electrode.

    PubMed

    Ouyang, Jun; Li, Zhong-Qiu; Zhang, Jing; Wang, Chen; Wang, Jiong; Xia, Xing-Hua; Zhou, Guo-Jun

    2014-07-01

    Hydroxyl radicals (˙OH) play an important role in human diseases. Traditional detection methods are time consuming and require expensive instruments. Here, we present a simple and sensitive method for the detection of hydroxyl radicals on a microfluidic chip using an electrochemical technique. Aniline monomer is electrochemically polymerized on the surface of a pencil graphite electrode and carbonized at 800 °C. The resulting N-doped porous carbon nanofiber-modified pencil graphite electrode is embedded into a microfluidic chip directly as a working electrode. 4-Hydroxybenzoic acid (4-HBA) is selected as the trapping agent owing to its unique 3,4-DHBA product and high trapping efficiency. A low detection limit of 1.0 × 10(-6) M is achieved on the microfluidic chip. As a demonstration, the microfluidic chip is successfully utilized for the detection of ˙OH in cigarette smoke. The strong π-π stacking and hydrophobic interactions between the nitrogen-doped carbon materials and the pencil graphite make the modified electrode well-suited for the microfluidic chip. PMID:24834984

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

    NASA Astrophysics Data System (ADS)

    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.

  10. A controlled microfluidic electrochemical lab-on-a-chip for label-free diffusion-restricted DNA hybridization analysis.

    PubMed

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

    2015-02-15

    Lab-on-a-chip (LOC) devices for electrochemical analysis of DNA hybridization events offer a technology for real-time and label-free assessment of biomarkers at the point-of-care. Here, we present a microfluidic LOC, with 3 × 3 arrayed electrochemical sensors for the analysis of DNA hybridization events. A new dual layer microfluidic valved manipulation system is integrated providing controlled and automated capabilities for high throughput analysis. This feature improves the repeatability, accuracy, and overall sensing performance (Fig. 1). The electrochemical activity of the fabricated microfluidic device is validated and demonstrated repeatable and reversible Nernstian characteristics. System design required detailed analysis of energy storage and dissipation as our sensing modeling involves diffusion-related electrochemical impedance spectroscopy. The effect of DNA hybridization on the calculated charge transfer resistance and the diffusional resistance components is evaluated. We demonstrate a specific device with an average cross-reactivity value of 27.5%. The device yields semilogarithmic dose response and enables a theoretical detection limit of 1 nM of complementary ssDNA target. This limit is lower than our previously reported non-valved device by 74% due to on-chip valve integration providing controlled and accurate assay capabilities. PMID:25310492

  11. Microfluidic Lab-on-a-Chip Platforms: Requirements, Characteristics and Applications

    NASA Astrophysics Data System (ADS)

    Mark, D.; Haeberle, S.; Roth, G.; von Stetten, F.; Zengerle, R.

    This review summarizes recent developments in microfluidic platform approaches. In contrast to isolated application-specific solutions, a microfluidic platform provides a set of fluidic unit operations, which are designed for easy combination within a well-defined fabrication technology. This allows the implementation of different application-specific (bio-) chemical processes, automated by microfluidic process integration [1]. A brief introduction into technical advances, major market segments and promising applications is followed by a detailed characterization of different microfluidic platforms, comprising a short definition, the functional principle, microfluidic unit operations, application examples as well as strengths and limitations. The microfluidic platforms in focus are lateral flow tests, linear actuated devices, pressure driven laminar flow, microfluidic large scale integration, segmented flow microfluidics, centrifugal microfluidics, electro-kinetics, electrowetting, surface acoustic waves, and systems for massively parallel analysis. The review concludes with the attempt to provide a selection scheme for microfluidic platforms which is based on their characteristics according to key requirements of different applications and market segments. Applied selection criteria comprise portability, costs of instrument and disposable, sample throughput, number of parameters per sample, reagent consumption, precision, diversity of microfluidic unit operations and the flexibility in programming different liquid handling protocols.

  12. Enzyme-based microfluidic chip coupled to graphene electrodes for the detection of D-amino acid enantiomer-biomarkers.

    PubMed

    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

  13. Flow control using audio tones in resonant microfluidic networks: towards cell-phone controlled lab-on-a-chip devices.

    PubMed

    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

  14. Selecting and designing with the right thermoplastic polymer for your microfluidic chip: a close look into cyclo-olefin polymer

    NASA Astrophysics Data System (ADS)

    Nevitt, Mark

    2013-03-01

    Engineers who are developing microfluidic devices and bioMEMs for life science applications have many aspects to consider when selecting the proper base materials for constructing a device. While glass and polydimethylsiloxane (PDMS) are the staple materials for proof-of-concept and prototype chip fabrication, they are not a feasible solution for commercial production due to their slow, labor-intensive production rate. Alternatively, a molded or extruded thermoplastic solution can deliver the precision, consistency, and high volume capability required for commercial scale production. Traditional thermoplastics, such as polymethylmethacrylate (PMMA), polycarbonate (PC), and polystyrene (PS), are well known by development engineers in the bioscience community; however, cyclo-olefin polymer (COP), a relative newcomer in the world of plastics, is gaining increasing attention for use in microfluidic devices due to its unique balance of key properties compared to conventional thermoplastics. In this paper, we provide a comprehensive look at the properties which make COP an excellent candidate for providing the flow cell support and reagent storage functions in microfluidic assays. We also explore the processing attributes and capabilities of COP resin and film which are crucial for manufacturing high-performance microfluidic devices.

  15. Fast and selective microfluidic chips for electrochemical antioxidant sensing in complex samples.

    PubMed

    Kovachev, Nikolay; Canals, Antonio; Escarpa, Alberto

    2010-04-01

    In this work, capillary electrophoresis chips with electrochemical detection have been assessed as creative and selective microfluidic platforms to integrate and simplify on a microscale the traditional methods for complex natural antioxidants determination. Depending on the acid-base properties of the analytes, two approaches (class-selective electrochemical index determination (CSEID) and individual antioxidant determination (IAD)) were investigated for the analysis of nine antioxidants ((+)-catechin, rutin, quercetin, chlorogenic, ferulic, caffeic, protocatechuic, vanillic, and gallic acids) in food samples. First, the novel concept of a class-selective electrochemical index is proposed allowing a fast and reliable determination of the main antioxidant classes (flavonoids and phenolic acids) in less than 100 s. In addition, an impressive separation of nine antioxidants is also offered in less than 260 s with the individual antioxidant determination approach. Qualitative and quantitative performances of both approaches were studied. The analytical figures of merit (i.e., electroosmotic flow (EOF) precision as relative standard deviation (RSD), resolution, signal precision as RSD, limit of detection, limit of quantification, and accuracy as recovery) of both approaches were <4%, approximately 1, < or = 5%, <8 microM, 30 microM, between 91% and 104%, and <4%, < or = 2%, <9%, < or = 6 microM, < or = 20 microM (with the exception of protocatechuic acid, which shows values of 40 and 130 microM, respectively), between 80% and 107% for the CSEID and IAD concepts, respectively, which are excellent for food samples analysis. A set of representative samples was analyzed including apple and pear skins and pulps, red and white wines, and green tea tablets. High agreement was observed between the results of the sample analyses from the two microchip-based approaches, and good correlation was observed with results obtained from traditional methods. Although the prominent

  16. Digital Microfluidic Logic Gates

    NASA Astrophysics Data System (ADS)

    Zhao, Yang; Xu, Tao; Chakrabarty, Krishnendu

    Microfluidic computing is an emerging application for microfluidics technology. We propose microfluidic logic gates based on digital microfluidics. Using the principle of electrowetting-on-dielectric, AND, OR, NOT and XOR gates are implemented through basic droplet-handling operations such as transporting, merging and splitting. The same input-output interpretation enables the cascading of gates to create nontrivial computing systems. We present a potential application for microfluidic logic gates by implementing microfluidic logic operations for on-chip HIV test.

  17. Dopamine-functionalized InP/ZnS quantum dots as fluorescence probes for the detection of adenosine in microfluidic chip

    PubMed Central

    Ankireddy, Seshadri Reddy; Kim, Jongsung

    2015-01-01

    Microbeads are frequently used as solid supports for biomolecules such as proteins and nucleic acids in heterogeneous microfluidic assays. Chip-based, quantum dot (QD)-bead-biomolecule probes have been used for the detection of various types of DNA. In this study, we developed dopamine (DA)-functionalized InP/ZnS QDs (QDs-DA) as fluorescence probes for the detection of adenosine in microfluidic chips. The photoluminescence (PL) intensity of the QDs-DA is quenched by Zn2+ because of the strong coordination interactions. In the presence of adenosine, Zn2+ cations preferentially bind to adenosine, and the PL intensity of the QDs-DA is recovered. A polydimethylsiloxane-based microfluidic chip was fabricated, and adenosine detection was confirmed using QDs-DA probes. PMID:26347351

  18. The Multi-organ Chip - A Microfluidic Platform for Long-term Multi-tissue Coculture

    PubMed Central

    Lorenz, Alexandra K.; Horland, Reyk; Schimek, Katharina M. S.; Busek, Mathias; Sonntag, Frank; Lauster, Roland; Marx, Uwe

    2015-01-01

    The ever growing amount of new substances released onto the market and the limited predictability of current in vitro test systems has led to a high need for new solutions for substance testing. Many drugs that have been removed from the market due to drug-induced liver injury released their toxic potential only after several doses of chronic testing in humans. However, a controlled microenvironment is pivotal for long-term multiple dosing experiments, as even minor alterations in extracellular conditions may greatly influence the cell physiology. We focused within our research program on the generation of a microengineered bioreactor, which can be dynamically perfused by an on-chip pump and combines at least two culture spaces for multi-organ applications. This circulatory system mimics the in vivo conditions of primary cell cultures better and assures a steadier, more quantifiable extracellular relay of signals to the cells. For demonstration purposes, human liver equivalents, generated by aggregating differentiated HepaRG cells with human hepatic stellate cells in hanging drop plates, were cocultured with human skin punch biopsies for up to 28 days inside the microbioreactor. The use of cell culture inserts enables the skin to be cultured at an air-liquid interface, allowing topical substance exposure. The microbioreactor system is capable of supporting these cocultures at near physiologic fluid flow and volume-to-liquid ratios, ensuring stable and organotypic culture conditions. The possibility of long-term cultures enables the repeated exposure to substances. Furthermore, a vascularization of the microfluidic channel circuit using human dermal microvascular endothelial cells yields a physiologically more relevant vascular model. PMID:25992921

  19. Automation of daphtoxkit-F biotest using a microfluidic lab-on-a-chip technology

    NASA Astrophysics Data System (ADS)

    Huang, Yushi; Nugegoda, Dayanthi; Wlodkowic, Donald

    2015-12-01

    An increased rigor in water quality monitoring is not only a legal requirement, but is also critical to ensure timely chemical hazard emergency responses and protection of human and animal health. Bioindication is a method that applies very sensitive living organisms to detect environmental changes using their natural responses. Although bioindicators do not deliver information on an exact type or intensity of toxicants present in water samples, they do provide an overall snapshot and early-warning information about presence of harmful and dangerous parameters. Despite the advantages of biotests performed on sentinel organisms, their wider application is limited by the nonexistence of high-throughput laboratory automation systems. As a result majority of biotests used in ecotoxicology require time-consuming and laborious manual procedures. In this work, we present development of a miniaturized Lab-on-a-Chip (LOC) platform for automation and enhancement of acute ecotoxicity test based on immobilization of a freshwater crustacean Daphnia magna (Daphtoxkit-FTM). Daphnids' immobilization in response to sudden changes in environment parameters is fast, unambiguous, and easy to record optically. We also for the first time demonstrate that LOC system enables studies of sub-lethal ecotoxic effects using behavioral responses of Daphnia magna as sentinels of water pollution. The system working principle incorporated a high definition (HD) time-resolved video data analysis to dynamically assess impact of the reference toxicant on swimming behavior of D. magna. Our system design combined: (i) microfluidic device for caging of Daphnia sp.; (ii) mechatronic interface for fluidic actuation; (iii) video data acquisition; and (iv) algorithms for animal movement tracking and analysis.

  20. Direct measurement of the dielectrophoresis forces acting on micro-objects using optical tweezers and a simple microfluidic chip

    NASA Astrophysics Data System (ADS)

    Park, In Soo; Park, Se Hee; Yoon, Dae Sung; Lee, Sang Woo; Kim, Beop-Min

    2014-09-01

    We constructed a reliable frequency-dependent dielectrophoretic (DEP) force measurement system based on optical tweezers and a microfluidic chip. Using this system, we directly measured the frequency-dependent DEP forces acting on polystyrene beads while varying various parameters, which were all verified by theoretical simulations. We also investigated the DEP characteristics of non-functionalized and carboxyl-functionalized polystyrene beads in solutions with different conductivities by associating the measured crossover frequencies with a theoretical DEP model. This system can be used as a quantifying tool for surface conductance assays by characterizing the DEP forces acting on micro-objects in various experimental conditions.

  1. Traceable clonal culture and chemodrug assay of heterogeneous prostate carcinoma PC3 cells in microfluidic single cell array chips

    PubMed Central

    Chung, Jaehoon; Ingram, Patrick N.; Bersano-Begey, Tom; Yoon, Euisik

    2014-01-01

    Cancer heterogeneity has received considerable attention for its role in tumor initiation and progression, and its implication for diagnostics and therapeutics in the clinic. To facilitate a cellular heterogeneity study in a low cost and highly efficient manner, we present a microfluidic platform that allows traceable clonal culture and characterization. The platform captures single cells into a microwell array and cultures them for clonal expansion, subsequently allowing on-chip characterization of clonal phenotype and response against drug treatments. Using a heterogeneous prostate cancer model, the PC3 cell line, we verified our prototype, identifying three different sub-phenotypes and correlating their clonal drug responsiveness to cell phenotype. PMID:25553180

  2. StyletChip: a microfluidic device for recording host invasion behaviour and feeding of plant parasitic nematodes.

    PubMed

    Hu, Chunxiao; Kearn, James; Urwin, Peter; Lilley, Catherine; O' Connor, Vincent; Holden-Dye, Lindy; Morgan, Hywel

    2014-07-21

    Plant parasitic nematodes (PPNs) infest the roots of crops and cause global losses with a severe economic impact on food production. Current chemical control agents are being removed from use due to environmental and toxicity concerns and there is a need for new approaches to crop protection. A key feature of parasitic behaviour for the majority of PPNs is a hollow stomastyle or odontostyle required for interaction with the host plant and feeding. This lance-like microscopic structure, often called a stylet, protrudes from the mouth of the worm and thrusts in a rhythmic manner to stab the host root. Studying stylet activity presents technical challenges and as a consequence the underlying biology is poorly understood. We have addressed this by designing a microfluidic chip which traps the PPN Globodera pallida and permits the recording of an electrophysiological signal concomitant with stylet thrusting. The PDMS chip incorporates a precisely designed aperture to trap the nematode securely around a mid-point of its body. It is fabricated using a novel combination of conventional photolithography and two photon polymerization. The chip incorporates valves for rapid application of test compounds and integral electrodes to facilitate acquisition of electrical signals. We show that stylet thrusting can be induced by controlled application of 5-HT (serotonin) to the worm. Each thrust and retraction produces an electrical waveform that characterises the physiological activity associated with the worm's behaviour. The ability to reproducibly record the stylet activity of PPNs provides a new platform for nematicide screening that specifically focuses on a behaviour that is integral to the parasite host interaction. This is the first report of a microfluidic chip capable of electrophysiological recording from nematodes other than Caenorhabditis elegans. The unique approach is optimised for trapping and recording from smaller worms or worms with distinct anterior body shapes

  3. Microfluidic Chip-Based Detection and Intraspecies Strain Discrimination of Salmonella Serovars Derived from Whole Blood of Septic Mice

    PubMed Central

    Patterson, Adriana S.; Heithoff, Douglas M.; Ferguson, Brian S.; Soh, H. Tom; Mahan, Michael J.

    2013-01-01

    Salmonella is a zoonotic pathogen that poses a considerable public health and economic burden in the United States and worldwide. Resultant human diseases range from enterocolitis to bacteremia to sepsis and are acutely dependent on the particular serovar of Salmonella enterica subsp. enterica, which comprises over 99% of human-pathogenic S. enterica isolates. Point-of-care methods for detection and strain discrimination of Salmonella serovars would thus have considerable benefit to medical, veterinary, and field applications that safeguard public health and reduce industry-associated losses. Here we describe a single, disposable microfluidic chip that supports isothermal amplification and sequence-specific detection and discrimination of Salmonella serovars derived from whole blood of septic mice. The integrated microfluidic electrochemical DNA (IMED) chip consists of an amplification chamber that supports loop-mediated isothermal amplification (LAMP), a rapid, single-temperature amplification method as an alternative to PCR that offers advantages in terms of sensitivity, reaction speed, and amplicon yield. The amplification chamber is connected via a microchannel to a detection chamber containing a reagentless, multiplexed (here biplex) sensing array for sequence-specific electrochemical DNA (E-DNA) detection of the LAMP products. Validation of the IMED device was assessed by the detection and discrimination of S. enterica subsp. enterica serovars Typhimurium and Choleraesuis, the causative agents of enterocolitis and sepsis in humans, respectively. IMED chips conferred rapid (under 2 h) detection and discrimination of these strains at clinically relevant levels (<1,000 CFU/ml) from whole, unprocessed blood collected from septic animals. The IMED-based chip assay shows considerable promise as a rapid, inexpensive, and portable point-of-care diagnostic platform for the detection and strain-specific discrimination of microbial pathogens. PMID:23354710

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

    PubMed Central

    Vlachova, Jana; Tmejova, Katerina; Kopel, Pavel; Korabik, Maria; Zitka, Jan; Hynek, David; Kynicky, Jindrich; Adam, Vojtech; Kizek, Rene

    2015-01-01

    Modification of carbon materials, especially graphene-based materials, has wide applications in electrochemical detection such as electrochemical lab-on-chip devices. A glassy carbon electrode (GCE) modified with chemically alternated graphene oxide was used as a working electrode (glassy carbon modified by graphene oxide with sulphur containing compounds and Nafion) for detection of nucleobases in hydrolysed samples (HCl pH = 2.9, 100 °C, 1 h, neutralization by NaOH). It was found out that modification, especially with trithiocyanuric acid, increased the sensitivity of detection in comparison with pure GCE. All processes were finally implemented in a microfluidic chip formed with a 3D printer by fused deposition modelling technology. As a material for chip fabrication, acrylonitrile butadiene styrene was chosen because of its mechanical and chemical stability. The chip contained the one chamber for the hydrolysis of the nucleic acid and another for the electrochemical detection by the modified GCE. This chamber was fabricated to allow for replacement of the GCE. PMID:25621613

  5. Microfluidic chip-based nano-liquid chromatography tandem mass spectrometry for quantification of aflatoxins in peanut products.

    PubMed

    Liu, Hsiang-Yu; Lin, Shu-Ling; Chan, Shan-An; Lin, Tzuen-Yeuan; Fuh, Ming-Ren

    2013-09-15

    Aflatoxins (AFs), a group of mycotoxins, are generally produced by fungi Aspergillus species. The naturally occurring AFs including AFB1, AFB2, AFG1, and AFG2 have been clarified as group 1 human carcinogen by International Agency for Research on Cancer. Developing a sensitive analytical method has become an important issue to accurately quantify trace amount of AFs in foodstuffs. In this study, we employed a microfluidic chip-based nano LC (chip-nanoLC) coupled to triple quadrupole mass spectrometer (QqQ-MS) system for the quantitative determination of AFs in peanuts and related products. Gradient elution and multiple reaction monitoring were utilized for chromatographic separation and MS measurements. Solvent extraction followed by immunoaffinity solid-phase extraction was employed to isolate analytes and reduce matrix effect from sample prior to chip-nanoLC/QqQ-MS analysis. Good recoveries were found to be in the range of 90.8%-100.4%. The linear range was 0.048-16 ng g(-1) for AFB1, AFB2, AFG1, AFG2 and AFM1. Limits of detection were estimated as 0.004-0.008 ng g(-1). Good intra-day/inter-day precision (2.3%-9.5%/2.3%-6.6%) and accuracy (96.1%-105.7%/95.5%-104.9%) were obtained. The applicability of this newly developed chip-nanoLC/QqQ-MS method was demonstrated by determining the AFs in various peanut products purchased from local markets. PMID:23708626

  6. Creating Sub-50 Nm Nanofluidic Junctions in PDMS Microfluidic Chip via Self-Assembly Process of Colloidal Particles.

    PubMed

    Wei, Xi; Syed, Abeer; Mao, Pan; Han, Jongyoon; Song, Yong-Ak

    2016-01-01

    Polydimethylsiloxane (PDMS) is the prevailing building material to make microfluidic devices due to its ease of molding and bonding as well as its transparency. Due to the softness of the PDMS material, however, it is challenging to use PDMS for building nanochannels. The channels tend to collapse easily during plasma bonding. In this paper, we present an evaporation-driven self-assembly method of silica colloidal nanoparticles to create nanofluidic junctions with sub-50 nm pores between two microchannels. The pore size as well as the surface charge of the nanofluidic junction is tunable simply by changing the colloidal silica bead size and surface functionalization outside of the assembled microfluidic device in a vial before the self-assembly process. Using the self-assembly of nanoparticles with a bead size of 300 nm, 500 nm, and 900 nm, it was possible to fabricate a porous membrane with a pore size of ~45 nm, ~75 nm and ~135 nm, respectively. Under electrical potential, this nanoporous membrane initiated ion concentration polarization (ICP) acting as a cation-selective membrane to concentrate DNA by ~1,700 times within 15 min. This non-lithographic nanofabrication process opens up a new opportunity to build a tunable nanofluidic junction for the study of nanoscale transport processes of ions and molecules inside a PDMS microfluidic chip. PMID:27023724

  7. A coral-on-a-chip microfluidic platform enabling live-imaging microscopy of reef-building corals

    PubMed Central

    Shapiro, Orr H.; Kramarsky-Winter, Esti; Gavish, Assaf R.; Stocker, Roman; Vardi, Assaf

    2016-01-01

    Coral reefs, and the unique ecosystems they support, are facing severe threats by human activities and climate change. Our understanding of these threats is hampered by the lack of robust approaches for studying the micro-scale interactions between corals and their environment. Here we present an experimental platform, coral-on-a-chip, combining micropropagation and microfluidics to allow direct microscopic study of live coral polyps. The small and transparent coral micropropagates are ideally suited for live-imaging microscopy, while the microfluidic platform facilitates long-term visualization under controlled environmental conditions. We demonstrate the usefulness of this approach by imaging coral micropropagates at previously unattainable spatio-temporal resolutions, providing new insights into several micro-scale processes including coral calcification, coral–pathogen interaction and the loss of algal symbionts (coral bleaching). Coral-on-a-chip thus provides a powerful method for studying coral physiology in vivo at the micro-scale, opening new vistas in coral biology. PMID:26940983

  8. The microfluidic chip module for the detection of murine norovirus in oysters using charge switchable micro-bead beating.

    PubMed

    Chung, Sung Hee; Baek, Changyoon; Cong, Vu Tan; Min, Junhong

    2015-05-15

    Sample preparation has recently been an issue in the detection of food poisoning pathogens, particularly viruses such as norovirus (NoV), in food because of the complexity of foods and raw fresh materials. Here, we demonstrate a total analytical microfluidic chip module to automatically perform a series of essential processes (cell concentration, lysis (RNA extraction), nucleic acid amplification, and detection) for the fast but sensitive detection of norovirus in oysters. The murine NoV spiked oyster was stomached using a standard method. The supernatant was first loaded into a shape switchable sample preparation chamber consisting of charge switchable micro-beads. Murine NoV, which was adsorbed on microbeads by electrostatic physisorption, was lysed using bead beating. The extracted RNA was transferred to the detection chamber to be amplified using Nucleic Acid Sequence Based Amplification (NASBA). The optimal surface functionality, size, and number of microbeads were achieved for the virus concentration and the stable RNA extraction in the shape-switchable micro-channel. As a result, murine NoV in a single oyster was successfully detected within 4h by the microfluidic chip developed here, and could be directly applied to the large volume environmental sample as well as the food sample. PMID:25449875

  9. Comprehensive analysis of alternating current electrokinetics induced motion of colloidal particles in a three-dimensional microfluidic chip

    NASA Astrophysics Data System (ADS)

    Honegger, Thibault; Peyrade, David

    2013-05-01

    AC electrokinetics is becoming a strategic tool for lab-on-a-chip systems due to its versatility and its high level of integration. The ability to foreseen the behaviour of fluids and particles under non-uniform AC electric fields is important to allow new generations of devices. Though most of studies predicted motion of particles in co-planar electrodes configurations, we explore a pure 3-D AC electrokinetic effect that can open the way to enhance contact-less handling throughout the microchannel. By fabricating 3D microfluidic chips with a bi-layer electrodes configuration where electrodes are patterned on both sides of the microfluidic channel, we present a detailed study of the AC electrokinetic regimes that govern particles motion suspended in different host media subjected to a non-uniform AC electric field that spreads through the cross-section of the microchannel. We simulate and observe the motion of 1, 5, and 10 μm polystyrene particles relative to the electrodes and provide an insight on the competition between electro-hydrodynamical forces and dielectrophoresis. We demonstrate that using relevant electrode designs combined with the appropriate applied AC potential, particles can be handled in 3-D in the micro-channel at a single or a collective level in several medium conductivities. Both numerical simulations and experimental results provide a useful basis for future biological applications.

  10. High-throughput and clogging-free microfluidic filtration platform for on-chip cell separation from undiluted whole blood.

    PubMed

    Cheng, Yinuo; Ye, Xiongying; Ma, Zengshuai; Xie, Shuai; Wang, Wenhui

    2016-01-01

    Rapid separation of white blood cells from whole blood sample is often required for their subsequent analyses of functions and phenotypes, and many advances have been made in this field. However, most current microfiltration-based cell separation microfluidic chips still suffer from low-throughput and membrane clogging. This paper reports on a high-throughput and clogging-free microfluidic filtration platform, which features with an integrated bidirectional micropump and commercially available polycarbonate microporous membranes. The integrated bidirectional micropump enables the fluid to flush micropores back and forth, effectively avoiding membrane clogging. The microporous membrane allows red blood cells passing through high-density pores in a cross-flow mixed with dead-end filtration mode. All the separation processes, including blood and buffer loading, separation, and sample collection, are automatically controlled for easy operation and high throughput. Both microbead mixture and undiluted whole blood sample are separated by the platform effectively. In particular, for white blood cell separation, the chip recovered 72.1% white blood cells with an over 232-fold enrichment ratio at a throughput as high as 37.5 μl/min. This high-throughput, clogging-free, and highly integrated platform holds great promise for point-of-care blood pretreatment, analysis, and diagnosis applications. PMID:26909124