Low-Cost Rapid Prototyping of Whole-Glass Microfluidic Devices

ERIC Educational Resources Information Center

Yuen, Po Ki; Goral, Vasiliy N.

2012-01-01

A low-cost, straightforward, rapid prototyping of whole-glass microfluidic devices is presented using glass-etching cream that can be easily purchased in local stores. A self-adhered vinyl stencil cut out by a desktop digital craft cutter was used as an etching mask for patterning microstructures in glass using the glass-etching cream. A specific…

Shrink film patterning by craft cutter: complete plastic chips with high resolution/high-aspect ratio channel.

PubMed

Taylor, Douglas; Dyer, David; Lew, Valerie; Khine, Michelle

2010-09-21

This paper presents a rapid, ultra-low-cost approach to fabricate microfluidic devices using a polyolefin shrink film and a digital craft cutter. The shrinking process (with a 95% reduction in area) results in relatively uniform and consistent microfluidic channels with smooth surfaces, vertical sidewalls, and high aspect ratio channels with lateral resolutions well beyond the tool used to cut them. The thermal bonding of the layers results in strongly bonded devices. Complex microfluidic designs are easily designed on the fly and protein assays are also readily integrated into the device. Full device characterization including channel consistency, optical properties, and bonding strength are assessed in this technical note.

Digital microfluidic platform for radiochemistry

DOEpatents

Van Dam, Michael R.; Kim, Chang-Jin; Chen, Supin; Ding, Huijiang; Shah, Gaurav Jitendra; Keng, Pei Yuin

2016-11-01

Disclosed herein are methods of performing microchemical reactions and electro-wetting-on-dielectric devices (EWOD devices) for use in performing those reactions. These devices and method are particularly suited for preparing radiochemical compounds, particularly compounds containing .sup.18F.

Digital microfluidic platform for radiochemistry

DOEpatents

Van Dam, R. Michael; Kim, Chang -Jin; Chen, Supin; Ding, Huijiang; Shah, Gaurav Jitendra; Keng, Pei Yuin

2015-11-24

Disclosed herein are methods of performing microchemical reactions and electro-wetting-on-dielectric devices (EWOD devices) for use in performing those reactions. These devices and method are particularly suited for preparing radiochemical compounds, particularly compounds containing .sup.18F.

Microfluidic Devices for Forensic DNA Analysis: A Review.

PubMed

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

2016-08-05

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

Digital Microfluidics Assisted Sealing of Individual Magnetic Particles in Femtoliter-Sized Reaction Wells for Single-Molecule Detection.

PubMed

Decrop, Deborah; Ruiz, Elena Pérez; Kumar, Phalguni Tewari; Tripodi, Lisa; Kokalj, Tadej; Lammertyn, Jeroen

2017-01-01

Digital microfluidics has emerged in the last years as a promising liquid handling technology for a variety of applications. Here, we describe in detail how to build up an electrowetting-on-dielectric-based digital microfluidic chip with unique advantages for performing single-molecule detection. We illustrate how superparamagnetic particles can be printed with very high loading efficiency (over 98 %) and single-particle resolution in the microwell array patterned in the Teflon-AF ® surface of the grounding plate of the chip. Finally, the potential of the device for its application to single-molecule detection is demonstrated by the ultrasensitive detection of the biotinylated enzyme β-Galactosidase captured on streptavidin-coated particles in the described platform.

Development of a digital microfluidic platform for point of care testing

PubMed Central

Sista, Ramakrishna; Hua, Zhishan; Thwar, Prasanna; Sudarsan, Arjun; Srinivasan, Vijay; Eckhardt, Allen; Pollack, Michael; Pamula, Vamsee

2009-01-01

Point of care testing is playing an increasingly important role in improving the clinical outcome in health care management. The salient features of a point of care device are quick results, integrated sample preparation and processing, small sample volumes, portability, multifunctionality and low cost. In this paper, we demonstrate some of these salient features utilizing an electrowetting-based Digital Microfluidic platform. We demonstrate the performance of magnetic bead-based immunoassays (cardiac troponin I) on a digital microfluidic cartridge in less than 8 minutes using whole blood samples. Using the same microfluidic cartridge, a 40-cycle real-time polymerase chain reaction was performed within 12 minutes by shuttling a droplet between two thermal zones. We further demonstrate, on the same cartridge, the capability to perform sample preparation for bacterial and fungal infectious disease pathogens (methicillin-resistance Staphylococcus aureus and Candida albicans) and for human genomic DNA using magnetic beads. In addition to rapid results and integrated sample preparation, electrowetting-based digital microfluidic instruments are highly portable because fluid pumping is performed electronically. All the digital microfluidic chips presented here were fabricated on printed circuit boards utilizing mass production techniques that keep the cost of the chip low. Due to the modularity and scalability afforded by digital microfluidics, multifunctional testing capability, such as combinations within and between immunoassays, DNA amplification, and enzymatic assays, can be brought to the point of care at a relatively low cost because a single chip can be configured in software for different assays required along the path of care. PMID:19023472

Digital quantification of DNA via isothermal amplification on a self-driven microfluidic chip featuring hydrophilic film-coated polydimethylsiloxane.

PubMed

Ma, Yu-Dong; Chang, Wen-Hsin; Luo, Kang; Wang, Chih-Hung; Liu, Shih-Yuan; Yen, Wen-Hsiang; Lee, Gwo-Bin

2018-01-15

Loop-mediated isothermal amplification (LAMP) is a DNA amplification approach characterized by high sensitivity and specificity. In "digital LAMP", small quantities of both template DNA and reagents are encapsulated within a droplet or microwell, allowing for analysis of precious nucleic acid samples in shorter amounts of time relative to traditional DNA amplification protocols (e.g., PCR) with an improved limit of detection. In this study, an integrated, self-driven microfluidic chip was designed to carry out digital LAMP. The entire quantification process could be automatically performed on this chip via capillary forces enabled through microwells comprised of polydimethylsiloxane (PDMS) surfaces coated with a hydrophilic film; no external pumps were required. Moreover, digitized droplets could be separated from each other by normally-closed microvalves. The contact angle of the hydrophilic film-coated PDMS surface was only 14.3°. This is the first time that a rapid (30min) and simple method has been used to create hydrophilic PDMS surfaces that allow for digital LAMP to be performed in a self-driven microfluidic device. As a proof of concept, amplification of a gene specific to a vancomycin-resistant Enterococcus strain was performed on the developed microfluidic chip within 30min, and the limit of detection was only 11 copies with a volume of 30μL. This device may therefore become a promising tool for clinical diagnosis and point-of-care applications. Copyright © 2017 Elsevier B.V. All rights reserved.

Isothermal circular-strand-displacement polymerization of DNA and microRNA in digital microfluidic devices.

PubMed

Giuffrida, Maria Chiara; Zanoli, Laura Maria; D'Agata, Roberta; Finotti, Alessia; Gambari, Roberto; Spoto, Giuseppe

2015-02-01

Nucleic-acid amplification is a crucial step in nucleic-acid-sequence-detection assays. The use of digital microfluidic devices to miniaturize amplification techniques reduces the required sample volume and the analysis time and offers new possibilities for process automation and integration in a single device. The recently introduced droplet polymerase-chain-reaction (PCR) amplification methods require repeated cycles of two or three temperature-dependent steps during the amplification of the nucleic-acid target sequence. In contrast, low-temperature isothermal-amplification methods have no need for thermal cycling, thus requiring simplified microfluidic-device features. Here, the combined use of digital microfluidics and molecular-beacon (MB)-assisted isothermal circular-strand-displacement polymerization (ICSDP) to detect microRNA-210 sequences is described. MicroRNA-210 has been described as the most consistently and predominantly upregulated hypoxia-inducible factor. The nmol L(-1)-pmol L(-1) detection capabilities of the method were first tested by targeting single-stranded DNA sequences from the genetically modified Roundup Ready soybean. The ability of the droplet-ICSDP method to discriminate between full-matched, single-mismatched, and unrelated sequences was also investigated. The detection of a range of nmol L(-1)-pmol L(-1) microRNA-210 solutions compartmentalized in nanoliter-sized droplets was performed, establishing the ability of the method to detect as little as 10(-18) mol of microRNA target sequences compartmentalized in 20 nL droplets. The suitability of the method for biological samples was tested by detecting microRNA-210 from transfected K562 cells.

Digital microfluidics for automated hanging drop cell spheroid culture.

PubMed

Aijian, Andrew P; Garrell, Robin L

2015-06-01

Cell spheroids are multicellular aggregates, grown in vitro, that mimic the three-dimensional morphology of physiological tissues. Although there are numerous benefits to using spheroids in cell-based assays, the adoption of spheroids in routine biomedical research has been limited, in part, by the tedious workflow associated with spheroid formation and analysis. Here we describe a digital microfluidic platform that has been developed to automate liquid-handling protocols for the formation, maintenance, and analysis of multicellular spheroids in hanging drop culture. We show that droplets of liquid can be added to and extracted from through-holes, or "wells," and fabricated in the bottom plate of a digital microfluidic device, enabling the formation and assaying of hanging drops. Using this digital microfluidic platform, spheroids of mouse mesenchymal stem cells were formed and maintained in situ for 72 h, exhibiting good viability (>90%) and size uniformity (% coefficient of variation <10% intraexperiment, <20% interexperiment). A proof-of-principle drug screen was performed on human colorectal adenocarcinoma spheroids to demonstrate the ability to recapitulate physiologically relevant phenomena such as insulin-induced drug resistance. With automatable and flexible liquid handling, and a wide range of in situ sample preparation and analysis capabilities, the digital microfluidic platform provides a viable tool for automating cell spheroid culture and analysis. © 2014 Society for Laboratory Automation and Screening.

Simple telemedicine for developing regions: camera phones and paper-based microfluidic devices for real-time, off-site diagnosis.

PubMed

Martinez, Andres W; Phillips, Scott T; Carrilho, Emanuel; Thomas, Samuel W; Sindi, Hayat; Whitesides, George M

2008-05-15

This article describes a prototype system for quantifying bioassays and for exchanging the results of the assays digitally with physicians located off-site. The system uses paper-based microfluidic devices for running multiple assays simultaneously, camera phones or portable scanners for digitizing the intensity of color associated with each colorimetric assay, and established communications infrastructure for transferring the digital information from the assay site to an off-site laboratory for analysis by a trained medical professional; the diagnosis then can be returned directly to the healthcare provider in the field. The microfluidic devices were fabricated in paper using photolithography and were functionalized with reagents for colorimetric assays. The results of the assays were quantified by comparing the intensities of the color developed in each assay with those of calibration curves. An example of this system quantified clinically relevant concentrations of glucose and protein in artificial urine. The combination of patterned paper, a portable method for obtaining digital images, and a method for exchanging results of the assays with off-site diagnosticians offers new opportunities for inexpensive monitoring of health, especially in situations that require physicians to travel to patients (e.g., in the developing world, in emergency management, and during field operations by the military) to obtain diagnostic information that might be obtained more effectively by less valuable personnel.

Microfluidic Devices for Forensic DNA Analysis: A Review

PubMed Central

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

2016-01-01

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

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

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.

A switchable digital microfluidic droplet dye-laser.

PubMed

Kuehne, Alexander J C; Gather, Malte C; Eydelnant, Irwin A; Yun, Seok-Hyun; Weitz, David A; Wheeler, Aaron R

2011-11-07

Digital microfluidic devices allow the manipulation of droplets between two parallel electrodes. These electrodes can act as mirrors generating a micro-cavity, which can be exploited for a droplet dye-laser. Three representative laser-dyes with emission wavelengths spanning the whole visible spectrum are chosen to show the applicability of this concept. Sub-microlitre droplets of laser-dye solution are moved in and out of a lasing site on-chip to down-convert the UV-excitation light into blue, green and red laser-pulses. This journal is © The Royal Society of Chemistry 2011

Pneumatic oscillator circuits for timing and control of integrated microfluidics.

PubMed

Duncan, Philip N; Nguyen, Transon V; Hui, Elliot E

2013-11-05

Frequency references are fundamental to most digital systems, providing the basis for process synchronization, timing of outputs, and waveform synthesis. Recently, there has been growing interest in digital logic systems that are constructed out of microfluidics rather than electronics, as a possible means toward fully integrated laboratory-on-a-chip systems that do not require any external control apparatus. However, the full realization of this goal has not been possible due to the lack of on-chip frequency references, thus requiring timing signals to be provided from off-chip. Although microfluidic oscillators have been demonstrated, there have been no reported efforts to characterize, model, or optimize timing accuracy, which is the fundamental metric of a clock. Here, we report pneumatic ring oscillator circuits built from microfluidic valves and channels. Further, we present a compressible-flow analysis that differs fundamentally from conventional circuit theory, and we show the utility of this physically based model for the optimization of oscillator stability. Finally, we leverage microfluidic clocks to demonstrate circuits for the generation of phase-shifted waveforms, self-driving peristaltic pumps, and frequency division. Thus, pneumatic oscillators can serve as on-chip frequency references for microfluidic digital logic circuits. On-chip clocks and pumps both constitute critical building blocks on the path toward achieving autonomous laboratory-on-a-chip devices.

Microfluidics-Based PCR for Fusion Transcript Detection.

PubMed

Chen, Hui

2016-01-01

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

Taking Advantage of Reduced Droplet-surface Interaction to Optimize Transport of Bioanalytes in Digital Microfluidics

PubMed Central

Freire, Sergio L. S.; Thorne, Nathaniel; Wutkowski, Michael; Dao, Selina

2014-01-01

Digital microfluidics (DMF), a technique for manipulation of droplets, is a promising alternative for the development of “lab-on-a-chip” platforms. Often, droplet motion relies on the wetting of a surface, directly associated with the application of an electric field; surface interactions, however, make motion dependent on droplet contents, limiting the breadth of applications of the technique. Some alternatives have been presented to minimize this dependence. However, they rely on the addition of extra chemical species to the droplet or its surroundings, which could potentially interact with droplet moieties. Addressing this challenge, our group recently developed Field-DW devices to allow the transport of cells and proteins in DMF, without extra additives. Here, the protocol for device fabrication and operation is provided, including the electronic interface for motion control. We also continue the studies with the devices, showing that multicellular, relatively large, model organisms can also be transported, arguably unaffected by the electric fields required for device operation. PMID:25407533

Digital Microfluidics for Nucleic Acid Amplification

PubMed Central

Veigas, Bruno; Fortunato, Elvira; Martins, Rodrigo; Águas, Hugo; Igreja, Rui; Baptista, Pedro V.

2017-01-01

Digital Microfluidics (DMF) has emerged as a disruptive methodology for the control and manipulation of low volume droplets. In DMF, each droplet acts as a single reactor, which allows for extensive multiparallelization of biological and chemical reactions at a much smaller scale. DMF devices open entirely new and promising pathways for multiplex analysis and reaction occurring in a miniaturized format, thus allowing for healthcare decentralization from major laboratories to point-of-care with accurate, robust and inexpensive molecular diagnostics. Here, we shall focus on DMF platforms specifically designed for nucleic acid amplification, which is key for molecular diagnostics of several diseases and conditions, from pathogen identification to cancer mutations detection. Particular attention will be given to the device architecture, materials and nucleic acid amplification applications in validated settings. PMID:28672827

Partially filled electrodes for digital microfluidic devices

NASA Astrophysics Data System (ADS)

Pyne, D. G.; Salman, W. M.; Abdelgawad, M.; Sun, Y.

2013-07-01

As digital microfluidics technology evolves, the need for integrating additional elements (e.g., sensing/detection and heating elements) on the electrode increases. Consequently, electrode area for droplet actuation is reduced to create space for accommodating these additional elements, which undesirably affects force generation. Electrodes cannot simply be scaled larger to compensate for this loss of force, as this would also increase droplet volume and thereby compromise the advantages thought in miniaturization. Here, we present a study evaluating, numerically with preliminary experimental verification, different partially filled electrode designs and suggesting designs that combine high actuation forces with a large reduction in electrode area.

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

Manually operatable on-chip bistable pneumatic microstructures for microfluidic manipulations.

PubMed

Chen, Arnold; Pan, Tingrui

2014-09-07

Bistable microvalves are of particular interest because of their distinct nature of 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 since microfluidic devices as contemporary lab-on-a-chip platforms are transferring from research settings to low-resource environments with high integrability and a small form factor. In this paper, we first present manually operatable, on-chip bistable pneumatic microstructures (BPMs) 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 composed of a vacuum activation chamber (VAC) and a pressure release chamber (PRC), of which users have direct control through finger pressing to switch either to the bistable vacuum state (VS) or the 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 processes blood samples to identify the distinct blood types (A/B/O) on-chip.

Attractive design: an elution solvent optimization platform for magnetic-bead-based fractionation using digital microfluidics and design of experiments.

PubMed

Lafrenière, Nelson M; Mudrik, Jared M; Ng, Alphonsus H C; Seale, Brendon; Spooner, Neil; Wheeler, Aaron R

2015-04-07

There is great interest in the development of integrated tools allowing for miniaturized sample processing, including solid phase extraction (SPE). We introduce a new format for microfluidic SPE relying on C18-functionalized magnetic beads that can be manipulated in droplets in a digital microfluidic platform. This format provides the opportunity to tune the amount (and potentially the type) of stationary phase on-the-fly, and allows the removal of beads after the extraction (to enable other operations in same device-space), maintaining device reconfigurability. Using the new method, we employed a design of experiments (DOE) operation to enable automated on-chip optimization of elution solvent composition for reversed phase SPE of a model system. Further, conditions were selected to enable on-chip fractionation of multiple analytes. Finally, the method was demonstrated to be useful for online cleanup of extracts from dried blood spot (DBS) samples. We anticipate this combination of features will prove useful for separating a wide range of analytes, from small molecules to peptides, from complex matrices.

Picoliter DNA Sequencing Chemistry on an Electrowetting-based Digital Microfluidic Platform

PubMed Central

Ferguson Welch, Erin R.; Lin, Yan-You; Madison, Andrew; Fair, R.B.

2011-01-01

The results of investigations into performing DNA sequencing chemistry on a picoliter-scale electrowetting digital microfluidic platform are reported. Pyrosequencing utilizes pyrophosphate produced during nucleotide base addition to initiate a process ending with detection through a chemiluminescence reaction using firefly luciferase. The intensity of light produced during the reaction can be quantified to determine the number of bases added to the DNA strand. The logic-based control and discrete fluid droplets of a digital microfluidic device lend themselves well to the pyrosequencing process. Bead-bound DNA is magnetically held in a single location, and wash or reagent droplets added or split from it to circumvent product dilution. Here we discuss the dispensing, control, and magnetic manipulation of the paramagnetic beads used to hold target DNA. We also demonstrate and characterize the picoliter-scale reaction of luciferase with adenosine triphosphate to represent the detection steps of pyrosequencing and all necessary alterations for working on this scale. PMID:21298802

Self-digitization microfluidic chip for absolute quantification of mRNA in single cells.

PubMed

Thompson, Alison M; Gansen, Alexander; Paguirigan, Amy L; Kreutz, Jason E; Radich, Jerald P; Chiu, Daniel T

2014-12-16

Quantification of mRNA in single cells provides direct insight into how intercellular heterogeneity plays a role in disease progression and outcomes. Quantitative polymerase chain reaction (qPCR), the current gold standard for evaluating gene expression, is insufficient for providing absolute measurement of single-cell mRNA transcript abundance. Challenges include difficulties in handling small sample volumes and the high variability in measurements. Microfluidic digital PCR provides far better sensitivity for minute quantities of genetic material, but the typical format of this assay does not allow for counting of the absolute number of mRNA transcripts samples taken from single cells. Furthermore, a large fraction of the sample is often lost during sample handling in microfluidic digital PCR. Here, we report the absolute quantification of single-cell mRNA transcripts by digital, one-step reverse transcription PCR in a simple microfluidic array device called the self-digitization (SD) chip. By performing the reverse transcription step in digitized volumes, we find that the assay exhibits a linear signal across a wide range of total RNA concentrations and agrees well with standard curve qPCR. The SD chip is found to digitize a high percentage (86.7%) of the sample for single-cell experiments. Moreover, quantification of transferrin receptor mRNA in single cells agrees well with single-molecule fluorescence in situ hybridization experiments. The SD platform for absolute quantification of single-cell mRNA can be optimized for other genes and may be useful as an independent control method for the validation of mRNA quantification techniques.

Mechanistic evaluation of the pros and cons of digital RT-LAMP for HIV-1 viral load quantification on a microfluidic device and improved efficiency via a two-step digital protocol.

PubMed

Sun, Bing; Shen, Feng; McCalla, Stephanie E; Kreutz, Jason E; Karymov, Mikhail A; Ismagilov, Rustem F

2013-02-05

Here we used a SlipChip microfluidic device to evaluate the performance of digital reverse transcription-loop-mediated isothermal amplification (dRT-LAMP) for quantification of HIV viral RNA. Tests are needed for monitoring HIV viral load to control the emergence of drug resistance and to diagnose acute HIV infections. In resource-limited settings, in vitro measurement of HIV viral load in a simple format is especially needed, and single-molecule counting using a digital format could provide a potential solution. We showed here that when one-step dRT-LAMP is used for quantification of HIV RNA, the digital count is lower than expected and is limited by the yield of desired cDNA. We were able to overcome the limitations by developing a microfluidic protocol to manipulate many single molecules in parallel through a two-step digital process. In the first step we compartmentalize the individual RNA molecules (based on Poisson statistics) and perform reverse transcription on each RNA molecule independently to produce DNA. In the second step, we perform the LAMP amplification on all individual DNA molecules in parallel. Using this new protocol, we increased the absolute efficiency (the ratio between the concentration calculated from the actual count and the expected concentration) of dRT-LAMP 10-fold, from ∼2% to ∼23%, by (i) using a more efficient reverse transcriptase, (ii) introducing RNase H to break up the DNA:RNA hybrid, and (iii) adding only the BIP primer during the RT step. We also used this two-step method to quantify HIV RNA purified from four patient samples and found that in some cases, the quantification results were highly sensitive to the sequence of the patient's HIV RNA. We learned the following three lessons from this work: (i) digital amplification technologies, including dLAMP and dPCR, may give adequate dilution curves and yet have low efficiency, thereby providing quantification values that underestimate the true concentration. Careful validation is essential before a method is considered to provide absolute quantification; (ii) the sensitivity of dLAMP to the sequence of the target nucleic acid necessitates additional validation with patient samples carrying the full spectrum of mutations; (iii) for multistep digital amplification chemistries, such as a combination of reverse transcription with amplification, microfluidic devices may be used to decouple these steps from one another and to perform them under different, individually optimized conditions for improved efficiency.

Pressure driven digital logic in PDMS based microfluidic devices fabricated by multilayer soft lithography.

PubMed

Devaraju, Naga Sai Gopi K; Unger, Marc A

2012-11-21

Advances in microfluidics now allow an unprecedented level of parallelization and integration of biochemical reactions. However, one challenge still faced by the field has been the complexity and cost of the control hardware: one external pressure signal has been required for each independently actuated set of valves on chip. Using a simple post-modification to the multilayer soft lithography fabrication process, we present a new implementation of digital fluidic logic fully analogous to electronic logic with significant performance advances over the previous implementations. We demonstrate a novel normally closed static gain valve capable of modulating pressure signals in a fashion analogous to an electronic transistor. We utilize these valves to build complex fluidic logic circuits capable of arbitrary control of flows by processing binary input signals (pressure (1) and atmosphere (0)). We demonstrate logic gates and devices including NOT, NAND and NOR gates, bi-stable flip-flops, gated flip-flops (latches), oscillators, self-driven peristaltic pumps, delay flip-flops, and a 12-bit shift register built using static gain valves. This fluidic logic shows cascade-ability, feedback, programmability, bi-stability, and autonomous control capability. This implementation of fluidic logic yields significantly smaller devices, higher clock rates, simple designs, easy fabrication, and integration into MSL microfluidics.

A lab-on-chip for biothreat detection using single-molecule DNA mapping.

PubMed

Meltzer, Robert H; Krogmeier, Jeffrey R; Kwok, Lisa W; Allen, Richard; Crane, Bryan; Griffis, Joshua W; Knaian, Linda; Kojanian, Nanor; Malkin, Gene; Nahas, Michelle K; Papkov, Vyacheslav; Shaikh, Saad; Vyavahare, Kedar; Zhong, Qun; Zhou, Yi; Larson, Jonathan W; Gilmanshin, Rudolf

2011-03-07

Rapid, specific, and sensitive detection of airborne bacteria, viruses, and toxins is critical for biodefense, yet the diverse nature of the threats poses a challenge for integrated surveillance, as each class of pathogens typically requires different detection strategies. Here, we present a laboratory-on-a-chip microfluidic device (LOC-DLA) that integrates two unique assays for the detection of airborne pathogens: direct linear analysis (DLA) with unsurpassed specificity for bacterial threats and Digital DNA for toxins and viruses. The LOC-DLA device also prepares samples for analysis, incorporating upstream functions for concentrating and fractionating DNA. Both DLA and Digital DNA assays are single molecule detection technologies, therefore the assay sensitivities depend on the throughput of individual molecules. The microfluidic device and its accompanying operation protocols have been heavily optimized to maximize throughput and minimize the loss of analyzable DNA. We present here the design and operation of the LOC-DLA device, demonstrate multiplex detection of rare bacterial targets in the presence of 100-fold excess complex bacterial mixture, and demonstrate detection of picogram quantities of botulinum toxoid.

DNA assembly with error correction on a droplet digital microfluidics platform.

PubMed

Khilko, Yuliya; Weyman, Philip D; Glass, John I; Adams, Mark D; McNeil, Melanie A; Griffin, Peter B

2018-06-01

Custom synthesized DNA is in high demand for synthetic biology applications. However, current technologies to produce these sequences using assembly from DNA oligonucleotides are costly and labor-intensive. The automation and reduced sample volumes afforded by microfluidic technologies could significantly decrease materials and labor costs associated with DNA synthesis. The purpose of this study was to develop a gene assembly protocol utilizing a digital microfluidic device. Toward this goal, we adapted bench-scale oligonucleotide assembly methods followed by enzymatic error correction to the Mondrian™ digital microfluidic platform. We optimized Gibson assembly, polymerase chain reaction (PCR), and enzymatic error correction reactions in a single protocol to assemble 12 oligonucleotides into a 339-bp double- stranded DNA sequence encoding part of the human influenza virus hemagglutinin (HA) gene. The reactions were scaled down to 0.6-1.2 μL. Initial microfluidic assembly methods were successful and had an error frequency of approximately 4 errors/kb with errors originating from the original oligonucleotide synthesis. Relative to conventional benchtop procedures, PCR optimization required additional amounts of MgCl 2 , Phusion polymerase, and PEG 8000 to achieve amplification of the assembly and error correction products. After one round of error correction, error frequency was reduced to an average of 1.8 errors kb - 1 . We demonstrated that DNA assembly from oligonucleotides and error correction could be completely automated on a digital microfluidic (DMF) platform. The results demonstrate that enzymatic reactions in droplets show a strong dependence on surface interactions, and successful on-chip implementation required supplementation with surfactants, molecular crowding agents, and an excess of enzyme. Enzymatic error correction of assembled fragments improved sequence fidelity by 2-fold, which was a significant improvement but somewhat lower than expected compared to bench-top assays, suggesting an additional capacity for optimization.

Digital microfluidics: Droplet based logic gates

NASA Astrophysics Data System (ADS)

Cheow, Lih Feng; Yobas, Levent; Kwong, Dim-Lee

2007-01-01

The authors present microfluidic logic gates based on two-phase flows at low Reynold's number. The presence and the absence of a dispersed phase liquid (slug) in a continuous phase liquid represent 1 and 0, respectively. The working principle of these devices is based on the change in hydrodynamic resistance for a channel containing droplets. Logical operations including AND, OR, and NOT are demonstrated, and may pave the way for microfludic system automation and computation.

A poly(dimethylsiloxane) microfluidic sheet reversibly adhered on a glass plate for creation of emulsion droplets for droplet digital PCR.

PubMed

Nakashoji, Yuta; Tanaka, Hironari; Tsukagoshi, Kazuhiko; Hashimoto, Masahiko

2017-01-01

A PDMS microfluidic chip with T-junction channel geometry, two inlet reservoirs, and one outlet reservoir was reversibly adhered on a glass plate through the viscoelastic properties of PDMS. This formed a detachable microfluidic device for creation of water-in-oil emulsion droplets that were used as discrete reaction compartments for the droplet digital PCR. The PDMS/glass device could continuously produce monodisperse droplets without leakage of fluids using a vacuum-driven autonomous micropumping method. This droplet preparation technique only required evacuation of air dissolved in the PDMS before loading of oil and aqueous phases into separate inlet reservoirs. Degassing of the PDMS chip at approximately 300 Pa for 1.5 h in a vacuum desiccator gave 40 000 droplets in 80 min, which corresponded to a generation frequency of up to nine droplets per second. Over multiple runs the droplet creation was very reproducible, and the size reproducibility of generated droplets (polydispersity of up to 4.1%) was comparable to that acquired using other microfluidic droplet preparation techniques. Because the PDMS chip can be peeled off the glass plate, blocked channels can easily be fixed when they arise, and this extends the lifetime of the chip. Single DNA molecules partitioned into the droplets were successfully amplified by PCR. In addition, the droplet digital PCR platform allowed absolute quantification of low copy numbers of target DNA, and was robust against instrumental variance. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Microfluidic paper-based device for colorimetric determination of glucose based on a metal-organic framework acting as peroxidase mimetic.

PubMed

Ortiz-Gómez, Inmaculada; Salinas-Castillo, Alfonso; García, Amalia García; Álvarez-Bermejo, José Antonio; de Orbe-Payá, Ignacio; Rodríguez-Diéguez, Antonio; Capitán-Vallvey, Luis Fermín

2017-12-13

This work presents a microfluidic paper-based analytical device (μPAD) for glucose determination using a supported metal-organic framework (MOF) acting as a peroxidase mimic. The catalytic action of glucose oxidase (GOx) on glucose causes the formation of H 2 O 2 , and the MOF causes the oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) by H 2 O 2 to form a blue-green product with an absorption peak at 650 nm in the detection zone. A digital camera and the iOS feature of a smartphone are used for the quantitation of glucose with the S coordinate of the HSV color space as the analytical parameter. Different factors such as the concentration of TMB, GOx and MOF, pH and buffer, sample volume, reaction time and reagent position in the μPAD were optimized. Under optimal conditions, the value for the S coordinate increases linearly up to 150 μmol·L -1 glucose concentrations, with a 2.5 μmol·L -1 detection limit. The μPAD remains stable for 21 days under conventional storage conditions. Such an enzyme mimetic-based assay to glucose determination using Fe-MIL-101 MOF implemented in a microfluidic paper-based device possesses advantages over enzyme-based assays in terms of costs, durability and stability compared to other existing glucose determination methods. The procedure was applied to the determination of glucose in (spiked) serum and urine. Graphical abstract Schematic representation of microfluidic paper-based analytical device using metal-organic framework as a peroxidase mimic for colorimetric glucose detection with digital camera or smartphone and iOS app readout.

Buckling of Dielectric Elastomeric Plates for Electrically Active Microfludic Pumps

NASA Astrophysics Data System (ADS)

Holmes, Douglas; Tavakol, Behrouz; Bozlar, Michael; Froehlicher, Guillaume; Stone, Howard; Aksay, Ilhan

2013-11-01

Fluid flow can be directed and controlled by a variety of mechanisms within industrial and biological environments. Advances in microfluidic technology have required innovative ways to control fluid flow on a small scale, and the ability to actively control fluid flow within microfluidic devices is crucial for advancements in nanofluidics, biomedical fluidic devices, and digital microfluidics. In this work, we present a means for microfluidic control via the electrical actuation of thin, flexible valves within microfluidic channels. These structures consist of a dielectric elastomer confined between two compliant electrodes that can be actively and reversibly buckle out of plane to pump fluids from an applied voltage. The out-of-plane deformation can be quantified using two parameters: net change in surface area and the shape of deformation. Change in surface area depends on the voltage, while the deformation shape, which significantly affects the flow rate, is a function of voltage, and the pressure and volume of the chambers on each side of the thin plate. The use of solid electrodes enables a robust and reversible pumping mechanism that will have will enable advancements in rapid microfluidic diagnostics, adaptive materials, and artificial muscles.

Digital microfluidics: A promising technique for biochemical applications

NASA Astrophysics Data System (ADS)

Wang, He; Chen, Liguo; Sun, Lining

2017-12-01

Digital microfluidics (DMF) is a versatile microfluidics technology that has significant application potential in the areas of automation and miniaturization. In DMF, discrete droplets containing samples and reagents are controlled to implement a series of operations via electrowetting-on-dielectric. This process works by applying electrical potentials to an array of electrodes coated with a hydrophobic dielectric layer. Unlike microchannels, DMF facilitates precise control over multiple reaction processes without using complex pump, microvalve, and tubing networks. DMF also presents other distinct features, such as portability, less sample consumption, shorter chemical reaction time, flexibility, and easier combination with other technology types. Due to its unique advantages, DMF has been applied to a broad range of fields (e.g., chemistry, biology, medicine, and environment). This study reviews the basic principles of droplet actuation, configuration design, and fabrication of the DMF device, as well as discusses the latest progress in DMF from the biochemistry perspective.

Instrument for Real-Time Digital Nucleic Acid Amplification on Custom Microfluidic Devices

PubMed Central

Selck, David A.

2016-01-01

Nucleic acid amplification tests that are coupled with a digital readout enable the absolute quantification of single molecules, even at ultralow concentrations. Digital methods are robust, versatile and compatible with many amplification chemistries including isothermal amplification, making them particularly invaluable to assays that require sensitive detection, such as the quantification of viral load in occult infections or detection of sparse amounts of DNA from forensic samples. A number of microfluidic platforms are being developed for carrying out digital amplification. However, the mechanistic investigation and optimization of digital assays has been limited by the lack of real-time kinetic information about which factors affect the digital efficiency and analytical sensitivity of a reaction. Commercially available instruments that are capable of tracking digital reactions in real-time are restricted to only a small number of device types and sample-preparation strategies. Thus, most researchers who wish to develop, study, or optimize digital assays rely on the rate of the amplification reaction when performed in a bulk experiment, which is now recognized as an unreliable predictor of digital efficiency. To expand our ability to study how digital reactions proceed in real-time and enable us to optimize both the digital efficiency and analytical sensitivity of digital assays, we built a custom large-format digital real-time amplification instrument that can accommodate a wide variety of devices, amplification chemistries and sample-handling conditions. Herein, we validate this instrument, we provide detailed schematics that will enable others to build their own custom instruments, and we include a complete custom software suite to collect and analyze the data retrieved from the instrument. We believe assay optimizations enabled by this instrument will improve the current limits of nucleic acid detection and quantification, improving our fundamental understanding of single-molecule reactions and providing advancements in practical applications such as medical diagnostics, forensics and environmental sampling. PMID:27760148

Three-dimensional fit-to-flow microfluidic assembly.

PubMed

Chen, Arnold; Pan, Tingrui

2011-12-01

Three-dimensional microfluidics holds great promise for large-scale integration of versatile, digitalized, and multitasking fluidic manipulations for biological and clinical applications. Successful translation of microfluidic toolsets to these purposes faces persistent technical challenges, such as reliable system-level packaging, device assembly and alignment, and world-to-chip interface. In this paper, we extended our previously established fit-to-flow (F2F) world-to-chip interconnection scheme to a complete system-level assembly strategy that addresses the three-dimensional microfluidic integration on demand. The modular F2F assembly consists of an interfacial chip, pluggable alignment modules, and multiple monolithic layers of microfluidic channels, through which convoluted three-dimensional microfluidic networks can be easily assembled and readily sealed with the capability of reconfigurable fluid flow. The monolithic laser-micromachining process simplifies and standardizes the fabrication of single-layer pluggable polymeric modules, which can be mass-produced as the renowned Lego(®) building blocks. In addition, interlocking features are implemented between the plug-and-play microfluidic chips and the complementary alignment modules through the F2F assembly, resulting in facile and secure alignment with average misalignment of 45 μm. Importantly, the 3D multilayer microfluidic assembly has a comparable sealing performance as the conventional single-layer devices, providing an average leakage pressure of 38.47 kPa. The modular reconfigurability of the system-level reversible packaging concept has been demonstrated by re-routing microfluidic flows through interchangeable modular microchannel layers.

A Soft, Wearable Microfluidic Device for the Capture, Storage, and Colorimetric Sensing of Sweat

PubMed Central

Koh, Ahyeon; Kang, Daeshik; Xue, Yeguang; Lee, Seungmin; Pielak, Rafal M.; Kim, Jeonghyun; Hwang, Taehwan; Min, Seunghwan; Banks, Anthony; Bastien, Philippe; Manco, Megan C.; Wang, Liang; Ammann, Kaitlyn R.; Jang, Kyung-In; Won, Phillip; Han, Seungyong; Ghaffari, Roozbeh; Paik, Ungyu; Slepian, Marvin J.; Balooch, Guive; Huang, Yonggang; Rogers, John A.

2017-01-01

Capabilities in health monitoring via capture and quantitative chemical analysis of sweat could complement, or potentially obviate the need for, approaches based on sporadic assessment of blood samples. Established sweat monitoring technologies use simple fabric swatches and are limited to basic analysis in controlled laboratory or hospital settings. We present a collection of materials and device designs for soft, flexible and stretchable microfluidic systems, including embodiments that integrate wireless communication electronics, which can intimately and robustly bond to the surface of skin without chemical and mechanical irritation. This integration defines access points for a small set of sweat glands such that perspiration spontaneously initiates routing of sweat through a microfluidic network and set of reservoirs. Embedded chemical analyses respond in colorimetric fashion to markers such as chloride and hydronium ions, glucose and lactate. Wireless interfaces to digital image capture hardware serve as a means for quantitation. Human studies demonstrated the functionality of this microfluidic device during fitness cycling in a controlled environment and during long-distance bicycle racing in arid, outdoor conditions. The results include quantitative values for sweat rate, total sweat loss, pH and concentration of both chloride and lactate. PMID:27881826

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

PubMed

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

2013-06-07

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

Scalable Device for Automated Microbial Electroporation in a Digital Microfluidic Platform.

PubMed

Madison, Andrew C; Royal, Matthew W; Vigneault, Frederic; Chen, Liji; Griffin, Peter B; Horowitz, Mark; Church, George M; Fair, Richard B

2017-09-15

Electrowetting-on-dielectric (EWD) digital microfluidic laboratory-on-a-chip platforms demonstrate excellent performance in automating labor-intensive protocols. When coupled with an on-chip electroporation capability, these systems hold promise for streamlining cumbersome processes such as multiplex automated genome engineering (MAGE). We integrated a single Ti:Au electroporation electrode into an otherwise standard parallel-plate EWD geometry to enable high-efficiency transformation of Escherichia coli with reporter plasmid DNA in a 200 nL droplet. Test devices exhibited robust operation with more than 10 transformation experiments performed per device without cross-contamination or failure. Despite intrinsic electric-field nonuniformity present in the EP/EWD device, the peak on-chip transformation efficiency was measured to be 8.6 ± 1.0 × 10 8 cfu·μg -1 for an average applied electric field strength of 2.25 ± 0.50 kV·mm -1 . Cell survival and transformation fractions at this electroporation pulse strength were found to be 1.5 ± 0.3 and 2.3 ± 0.1%, respectively. Our work expands the EWD toolkit to include on-chip microbial electroporation and opens the possibility of scaling advanced genome engineering methods, like MAGE, into the submicroliter regime.

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

PubMed

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

2016-08-01

The open-source release of self-replicating rapid prototypers (RepRaps) has created a rich opportunity for low-cost distributed digital fabrication of complex 3-D objects such as scientific equipment. For example, 3-D printable reactionware devices offer the opportunity to combine open hardware microfluidic handling with lab-on-a-chip reactionware to radically reduce costs and increase the number and complexity of microfluidic applications. To further drive down the cost while improving the performance of lab-on-a-chip paper-based microfluidic prototyping, this study reports on the development of a RepRap upgrade capable of converting a Prusa Mendel RepRap into a wax 3-D printer for paper-based microfluidic applications. An open-source hardware approach is used to demonstrate a 3-D printable upgrade for the 3-D printer, which combines a heated syringe pump with the RepRap/Arduino 3-D control. The bill of materials, designs, basic assembly, and use instructions are provided, along with a completely free and open-source software tool chain. The open-source hardware device described here accelerates the potential of the nascent field of electrochemical detection combined with paper-based microfluidics by dropping the marginal cost of prototyping to nearly zero while accelerating the turnover between paper-based microfluidic designs. © 2016 Society for Laboratory Automation and Screening.

Droplet microfluidics for amplification-free genetic detection of single cells.

PubMed

Rane, Tushar D; Zec, Helena C; Puleo, Chris; Lee, Abraham P; Wang, Tza-Huei

2012-09-21

In this article we present a novel droplet microfluidic chip enabling amplification-free detection of single pathogenic cells. The device streamlines multiple functionalities to carry out sample digitization, cell lysis, probe-target hybridization for subsequent fluorescent detection. A peptide nucleic acid fluorescence resonance energy transfer probe (PNA beacon) is used to detect 16S rRNA present in pathogenic cells. Initially the sensitivity and quantification abilities of the platform are tested using a synthetic target mimicking the actual expression level of 16S rRNA in single cells. The capability of the device to perform "sample-to-answer" pathogen detection of single cells is demonstrated using E. coli as a model pathogen.

Photo-actuation of liquids for light-driven microfluidics: state of the art and perspectives.

PubMed

Baigl, Damien

2012-10-07

Using light to control liquid motion is a new paradigm for the actuation of microfluidic systems. We review here the different principles and strategies to induce or control liquid motion using light, which includes the use of radiation pressure, optical tweezers, light-induced wettability gradients, the thermocapillary effect, photosensitive surfactants, the chromocapillary effect, optoelectrowetting, photocontrolled electroosmotic flows and optical dielectrophoresis. We analyze the performance of these approaches to control using light many kinds of microfluidic operations involving discrete pL- to μL-sized droplets (generation, driving, mixing, reaction, sorting) or fluid flows in microchannels (valve operation, injection, pumping, flow rate control). We show that a complete toolbox is now available to control microfluidic systems by light. We finally discuss the perspectives of digital optofluidics as well as microfluidics based on all optical fluidic chips and optically reconfigurable devices.

Additive manufacturing of microfluidic glass chips

NASA Astrophysics Data System (ADS)

Kotz, F.; Helmer, D.; Rapp, B. E.

2018-02-01

Additive manufacturing has gained great interest in the microfluidic community due to the numerous channel designs which can be tested in the early phases of a lab-on-a-chip device development. High resolution additive manufacturing like microstereolithography is largely associated with polymers. Polymers are at a disadvantage compared to other materials due to their softness and low chemical resistance. Whenever high chemical and thermal resistance combined with high optical transparency is needed, glasses become the material of choice. However, glasses are difficult to structure at the microscale requiring hazardous chemicals for etching processes. In this work we present additive manufacturing and high resolution patterning of microfluidic chips in transparent fused silica glass using stereolithography and microlithography. We print an amorphous silica nanocomposite at room temperature using benchtop stereolithography printers and a custom built microlithography system based on a digital mirror device. Using microlithography we printed structures with tens of micron resolution. The printed part is then converted to a transparent fused silica glass using thermal debinding and sintering. Printing of a microfluidic chip can be done within 30 minutes. The heat treatment can be done within two days.

Microfluidic Biochip Design

NASA Technical Reports Server (NTRS)

Panzarella, Charles

2004-01-01

As humans prepare for the exploration of our solar system, there is a growing need for miniaturized medical and environmental diagnostic devices for use on spacecrafts, especially during long-duration space missions where size and power requirements are critical. In recent years, the biochip (or Lab-on-a-Chip) has emerged as a technology that might be able to satisfy this need. In generic terms, a biochip is a miniaturized microfluidic device analogous to the electronic microchip that ushered in the digital age. It consists of tiny microfluidic channels, pumps and valves that transport small amounts of sample fluids to biosensors that can perform a variety of tests on those fluids in near real time. It has the obvious advantages of being small, lightweight, requiring less sample fluids and reagents and being more sensitive and efficient than larger devices currently in use. Some of the desired space-based applications would be to provide smaller, more robust devices for analyzing blood, saliva and urine and for testing water and food supplies for the presence of harmful contaminants and microorganisms. Our group has undertaken the goal of adapting as well as improving upon current biochip technology for use in long-duration microgravity environments.

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

PubMed

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

2015-06-11

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

The dynamics and stability of lubricating oil films during droplet transport by electrowetting in microfluidic devices.

PubMed

Kleinert, Jairus; Srinivasan, Vijay; Rival, Arnaud; Delattre, Cyril; Velev, Orlin D; Pamula, Vamsee K

2015-05-01

The operation of digital microfluidic devices with water droplets manipulated by electrowetting is critically dependent on the static and dynamic stability and lubrication properties of the oil films that separate the droplets from the solid surfaces. The factors determining the stability of the films and preventing surface fouling in such systems are not yet thoroughly understood and were experimentally investigated in this study. The experiments were performed using a standard digital microfluidic cartridge in which water droplets enclosed in a thin, oil-filled gap were transported over an array of electrodes. Stable, continuous oil films separated the droplets from the surfaces when the droplets were stationary. During droplet transport, capillary waves formed in the films on the electrode surfaces as the oil menisci receded. The waves evolved into dome-shaped oil lenses. Droplet deformation and oil displacement caused the films at the surface opposite the electrode array to transform into dimples of oil trapped over the centers of the droplets. Lower actuation voltages were associated with slower film thinning and formation of fewer, but larger, oil lenses. Lower ac frequencies induced oscillations in the droplets that caused the films to rupture. Films were also destabilized by addition of surfactants to the oil or droplet phases. Such a comprehensive understanding of the oil film behavior will enable more robust electrowetting-actuated lab-on-a-chip devices through prevention of loss of species from droplets and contamination of surfaces at points where films may break.

The dynamics and stability of lubricating oil films during droplet transport by electrowetting in microfluidic devices

PubMed Central

Kleinert, Jairus; Srinivasan, Vijay; Rival, Arnaud; Delattre, Cyril; Velev, Orlin D.; Pamula, Vamsee K.

2015-01-01

The operation of digital microfluidic devices with water droplets manipulated by electrowetting is critically dependent on the static and dynamic stability and lubrication properties of the oil films that separate the droplets from the solid surfaces. The factors determining the stability of the films and preventing surface fouling in such systems are not yet thoroughly understood and were experimentally investigated in this study. The experiments were performed using a standard digital microfluidic cartridge in which water droplets enclosed in a thin, oil-filled gap were transported over an array of electrodes. Stable, continuous oil films separated the droplets from the surfaces when the droplets were stationary. During droplet transport, capillary waves formed in the films on the electrode surfaces as the oil menisci receded. The waves evolved into dome-shaped oil lenses. Droplet deformation and oil displacement caused the films at the surface opposite the electrode array to transform into dimples of oil trapped over the centers of the droplets. Lower actuation voltages were associated with slower film thinning and formation of fewer, but larger, oil lenses. Lower ac frequencies induced oscillations in the droplets that caused the films to rupture. Films were also destabilized by addition of surfactants to the oil or droplet phases. Such a comprehensive understanding of the oil film behavior will enable more robust electrowetting-actuated lab-on-a-chip devices through prevention of loss of species from droplets and contamination of surfaces at points where films may break. PMID:26045729

A soft, wearable microfluidic device for the capture, storage, and colorimetric sensing of sweat.

PubMed

Koh, Ahyeon; Kang, Daeshik; Xue, Yeguang; Lee, Seungmin; Pielak, Rafal M; Kim, Jeonghyun; Hwang, Taehwan; Min, Seunghwan; Banks, Anthony; Bastien, Philippe; Manco, Megan C; Wang, Liang; Ammann, Kaitlyn R; Jang, Kyung-In; Won, Phillip; Han, Seungyong; Ghaffari, Roozbeh; Paik, Ungyu; Slepian, Marvin J; Balooch, Guive; Huang, Yonggang; Rogers, John A

2016-11-23

Capabilities in health monitoring enabled by capture and quantitative chemical analysis of sweat could complement, or potentially obviate the need for, approaches based on sporadic assessment of blood samples. Established sweat monitoring technologies use simple fabric swatches and are limited to basic analysis in controlled laboratory or hospital settings. We present a collection of materials and device designs for soft, flexible, and stretchable microfluidic systems, including embodiments that integrate wireless communication electronics, which can intimately and robustly bond to the surface of the skin without chemical and mechanical irritation. This integration defines access points for a small set of sweat glands such that perspiration spontaneously initiates routing of sweat through a microfluidic network and set of reservoirs. Embedded chemical analyses respond in colorimetric fashion to markers such as chloride and hydronium ions, glucose, and lactate. Wireless interfaces to digital image capture hardware serve as a means for quantitation. Human studies demonstrated the functionality of this microfluidic device during fitness cycling in a controlled environment and during long-distance bicycle racing in arid, outdoor conditions. The results include quantitative values for sweat rate, total sweat loss, pH, and concentration of chloride and lactate. Copyright © 2016, American Association for the Advancement of Science.

A Digital Microfluidics Platform for Loop-Mediated Isothermal Amplification Detection

PubMed Central

Veigas, Bruno; Águas, Hugo; Fortunato, Elvira; Martins, Rodrigo; Baptista, Pedro Viana; Igreja, Rui

2017-01-01

Digital microfluidics (DMF) arises as the next step in the fast-evolving field of operation platforms for molecular diagnostics. Moreover, isothermal schemes, such as loop-mediated isothermal amplification (LAMP), allow for further simplification of amplification protocols. Integrating DMF with LAMP will be at the core of a new generation of detection devices for effective molecular diagnostics at point-of-care (POC), providing simple, fast, and automated nucleic acid amplification with exceptional integration capabilities. Here, we demonstrate for the first time the role of coupling DMF and LAMP, in a dedicated device that allows straightforward mixing of LAMP reagents and target DNA, as well as optimum temperature control (reaction droplets undergo a temperature variation of just 0.3 °C, for 65 °C at the bottom plate). This device is produced using low-temperature and low-cost production processes, adaptable to disposable and flexible substrates. DMF-LAMP is performed with enhanced sensitivity without compromising reaction efficacy or losing reliability and efficiency, by LAMP-amplifying 0.5 ng/µL of target DNA in just 45 min. Moreover, on-chip LAMP was performed in 1.5 µL, a considerably lower volume than standard bench-top reactions. PMID:29144379

Investigation on microfluidic particles manipulation by holographic 3D tracking strategies

NASA Astrophysics Data System (ADS)

Cacace, Teresa; Paturzo, Melania; Memmolo, Pasquale; Vassalli, Massimo; Fraldi, Massimiliano; Mensitieri, Giuseppe; Ferraro, Pietro

2017-06-01

We demonstrate a 3D holographic tracking method to investigate particles motion in a microfluidic channel while unperturbed while inducing their migration through microfluidic manipulation. Digital holography (DH) in microscopy is a full-field, label-free imaging technique able to provide quantitative phase-contrast. The employed 3D tracking method is articulated in steps. First, the displacements along the optical axis are assessed by numerical refocusing criteria. In particular, an automatic refocusing method to recover the particles axial position is implemented employing a contrast-based refocusing criterion. Then, the transverse position of the in-focus object is evaluated through quantitative phase map segmentation methods and centroid-based 2D tracking strategy. The introduction of DH is thus suggested as a powerful approach for control of particles and biological samples manipulation, as well as a possible aid to precise design and implementation of advanced lab-on-chip microfluidic devices.

Research highlights: printing the future of microfabrication.

PubMed

Tseng, Peter; Murray, Coleman; Kim, Donghyuk; Di Carlo, Dino

2014-05-07

In this issue we highlight emerging microfabrication approaches suitable for microfluidic systems with a focus on "additive manufacturing" processes (i.e. printing). In parallel with the now-wider availability of low cost consumer-grade 3D printers (as evidenced by at least three brands of 3D printers for sale in a recent visit to an electronics store in Akihabara, Tokyo), commercial-grade 3D printers are ramping to higher and higher resolution with new capabilities, such as printing of multiple materials of different transparency, and with different mechanical and electrical properties. We highlight new work showing that 3D printing (stereolithography approaches in particular) has now risen as a viable technology to print whole microfluidic devices. Printing on 2D surfaces such as paper is an everyday experience, and has been used widely in analytical chemistry for printing conductive materials on paper strips for glucose and other electrochemical sensors. We highlight recent work using electrodes printed on paper for digital microfluidic droplet actuation. Finally, we highlight recent work in which printing of membrane-bound droplets that interconnect through bilayer membranes may open up an entirely new approach to microfluidic manufacturing of soft devices that mimic physiological systems.

Single-Cell RT-PCR in Microfluidic Droplets with Integrated Chemical Lysis.

PubMed

Kim, Samuel C; Clark, Iain C; Shahi, Payam; Abate, Adam R

2018-01-16

Droplet microfluidics can identify and sort cells using digital reverse transcription polymerase chain reaction (RT-PCR) signals from individual cells. However, current methods require multiple microfabricated devices for enzymatic cell lysis and PCR reagent addition, making the process complex and prone to failure. Here, we describe a new approach that integrates all components into a single device. The method enables controlled exposure of isolated single cells to a high pH buffer, which lyses cells and inactivates reaction inhibitors but can be instantly neutralized with RT-PCR buffer. Using our chemical lysis approach, we distinguish individual cells' gene expression with data quality equivalent to more complex two-step workflows. Our system accepts cells and produces droplets ready for amplification, making single-cell droplet RT-PCR faster and more reliable.

DNA Assembly in 3D Printed Fluidics

PubMed Central

Patrick, William G.; Nielsen, Alec A. K.; Keating, Steven J.; Levy, Taylor J.; Wang, Che-Wei; Rivera, Jaime J.; Mondragón-Palomino, Octavio; Carr, Peter A.; Voigt, Christopher A.; Oxman, Neri; Kong, David S.

2015-01-01

The process of connecting genetic parts—DNA assembly—is a foundational technology for synthetic biology. Microfluidics present an attractive solution for minimizing use of costly reagents, enabling multiplexed reactions, and automating protocols by integrating multiple protocol steps. However, microfluidics fabrication and operation can be expensive and requires expertise, limiting access to the technology. With advances in commodity digital fabrication tools, it is now possible to directly print fluidic devices and supporting hardware. 3D printed micro- and millifluidic devices are inexpensive, easy to make and quick to produce. We demonstrate Golden Gate DNA assembly in 3D-printed fluidics with reaction volumes as small as 490 nL, channel widths as fine as 220 microns, and per unit part costs ranging from $0.61 to $5.71. A 3D-printed syringe pump with an accompanying programmable software interface was designed and fabricated to operate the devices. Quick turnaround and inexpensive materials allowed for rapid exploration of device parameters, demonstrating a manufacturing paradigm for designing and fabricating hardware for synthetic biology. PMID:26716448

Self-powered integrated microfluidic point-of-care low-cost enabling (SIMPLE) chip

PubMed Central

Yeh, Erh-Chia; Fu, Chi-Cheng; Hu, Lucy; Thakur, Rohan; Feng, Jeffrey; Lee, Luke P.

2017-01-01

Portable, low-cost, and quantitative nucleic acid detection is desirable for point-of-care diagnostics; however, current polymerase chain reaction testing often requires time-consuming multiple steps and costly equipment. We report an integrated microfluidic diagnostic device capable of on-site quantitative nucleic acid detection directly from the blood without separate sample preparation steps. First, we prepatterned the amplification initiator [magnesium acetate (MgOAc)] on the chip to enable digital nucleic acid amplification. Second, a simplified sample preparation step is demonstrated, where the plasma is separated autonomously into 224 microwells (100 nl per well) without any hemolysis. Furthermore, self-powered microfluidic pumping without any external pumps, controllers, or power sources is accomplished by an integrated vacuum battery on the chip. This simple chip allows rapid quantitative digital nucleic acid detection directly from human blood samples (10 to 105 copies of methicillin-resistant Staphylococcus aureus DNA per microliter, ~30 min, via isothermal recombinase polymerase amplification). These autonomous, portable, lab-on-chip technologies provide promising foundations for future low-cost molecular diagnostic assays. PMID:28345028

Digital biology and chemistry.

PubMed

Witters, Daan; Sun, Bing; Begolo, Stefano; Rodriguez-Manzano, Jesus; Robles, Whitney; Ismagilov, Rustem F

2014-09-07

This account examines developments in "digital" biology and chemistry within the context of microfluidics, from a personal perspective. Using microfluidics as a frame of reference, we identify two areas of research within digital biology and chemistry that are of special interest: (i) the study of systems that switch between discrete states in response to changes in chemical concentration of signals, and (ii) the study of single biological entities such as molecules or cells. In particular, microfluidics accelerates analysis of switching systems (i.e., those that exhibit a sharp change in output over a narrow range of input) by enabling monitoring of multiple reactions in parallel over a range of concentrations of signals. Conversely, such switching systems can be used to create new kinds of microfluidic detection systems that provide "analog-to-digital" signal conversion and logic. Microfluidic compartmentalization technologies for studying and isolating single entities can be used to reconstruct and understand cellular processes, study interactions between single biological entities, and examine the intrinsic heterogeneity of populations of molecules, cells, or organisms. Furthermore, compartmentalization of single cells or molecules in "digital" microfluidic experiments can induce switching in a range of reaction systems to enable sensitive detection of cells or biomolecules, such as with digital ELISA or digital PCR. This "digitizing" offers advantages in terms of robustness, assay design, and simplicity because quantitative information can be obtained with qualitative measurements. While digital formats have been shown to improve the robustness of existing chemistries, we anticipate that in the future they will enable new chemistries to be used for quantitative measurements, and that digital biology and chemistry will continue to provide further opportunities for measuring biomolecules, understanding natural systems more deeply, and advancing molecular and cellular analysis. Microfluidics will impact digital biology and chemistry and will also benefit from them if it becomes massively distributed.

3D nanofabrication inside rapid prototyped microfluidic channels showcased by wet-spinning of single micrometre fibres.

PubMed

Lölsberg, Jonas; Linkhorst, John; Cinar, Arne; Jans, Alexander; Kuehne, Alexander J C; Wessling, Matthias

2018-05-01

Microfluidics is an established multidisciplinary research domain with widespread applications in the fields of medicine, biotechnology and engineering. Conventional production methods of microfluidic chips have been limited to planar structures, preventing the exploitation of truly three-dimensional architectures for applications such as multi-phase droplet preparation or wet-phase fibre spinning. Here the challenge of nanofabrication inside a microfluidic chip is tackled for the showcase of a spider-inspired spinneret. Multiphoton lithography, an additive manufacturing method, was used to produce free-form microfluidic masters, subsequently replicated by soft lithography. Into the resulting microfluidic device, a three-dimensional spider-inspired spinneret was directly fabricated in-chip via multiphoton lithography. Applying this unprecedented fabrication strategy, the to date smallest printed spinneret nozzle is produced. This spinneret resides tightly sealed, connecting it to the macroscopic world. Its functionality is demonstrated by wet-spinning of single-digit micron fibres through a polyacrylonitrile coagulation process induced by a water sheath layer. The methodology developed here demonstrates fabrication strategies to interface complex architectures into classical microfluidic platforms. Using multiphoton lithography for in-chip fabrication adopts a high spatial resolution technology for improving geometry and thus flow control inside microfluidic chips. The showcased fabrication methodology is generic and will be applicable to multiple challenges in fluid control and beyond.

Self-priming compartmentalization digital LAMP for point-of-care.

PubMed

Zhu, Qiangyuan; Gao, Yibo; Yu, Bingwen; Ren, Hao; Qiu, Lin; Han, Sihai; Jin, Wei; Jin, Qinhan; Mu, Ying

2012-11-21

Digital nucleic acid amplification provides unprecedented opportunities for absolute nucleic acid quantification by counting of single molecules. This technique is useful for molecular genetic analysis in cancer, stem cell, bacterial, non-invasive prenatal diagnosis in which many biologists are interested. This paper describes a self-priming compartmentalization (SPC) microfluidic chip platform for performing digital loop-mediated amplification (LAMP). The energy for the pumping is pre-stored in the degassed bulk PDMS by exploiting the high gas solubility of PDMS; therefore, no additional structures other than channels and reservoirs are required. The sample and oil are sequentially sucked into the channels, and the pressure difference of gas dissolved in PDMS allows sample self-compartmentalization without the need for further chip manipulation such as with pneumatic microvalves and control systems, and so on. The SPC digital LAMP chip can be used like a 384-well plate, so, the world-to-chip fluidic interconnections are avoided. The microfluidic chip contains 4 separate panels, each panel contains 1200 independent 6 nL chambers and can be used to detect 4 samples simultaneously. Digital LAMP on the microfluidic chip was tested quantitatively by using β-actin DNA from humans. The self-priming compartmentalization behavior is roughly predictable using a two-dimensional model. The uniformity of compartmentalization was analyzed by fluorescent intensity and fraction of volume. The results showed that the feasibility and flexibility of the microfluidic chip platform for amplifying single nucleic acid molecules in different chambers made by diluting and distributing sample solutions. The SPC chip has the potential to meet the requirements of a general laboratory: power-free, valve-free, operating at isothermal temperature, inexpensive, sensitive, economizing labour time and reagents. The disposable analytical devices with appropriate air-tight packaging should be useful for point-of-care, and enabling it to become one of the common tools for biology research, especially, in point-of-care testing.

Machine vision for digital microfluidics

NASA Astrophysics Data System (ADS)

Shin, Yong-Jun; Lee, Jeong-Bong

2010-01-01

Machine vision is widely used in an industrial environment today. It can perform various tasks, such as inspecting and controlling production processes, that may require humanlike intelligence. The importance of imaging technology for biological research or medical diagnosis is greater than ever. For example, fluorescent reporter imaging enables scientists to study the dynamics of gene networks with high spatial and temporal resolution. Such high-throughput imaging is increasingly demanding the use of machine vision for real-time analysis and control. Digital microfluidics is a relatively new technology with expectations of becoming a true lab-on-a-chip platform. Utilizing digital microfluidics, only small amounts of biological samples are required and the experimental procedures can be automatically controlled. There is a strong need for the development of a digital microfluidics system integrated with machine vision for innovative biological research today. In this paper, we show how machine vision can be applied to digital microfluidics by demonstrating two applications: machine vision-based measurement of the kinetics of biomolecular interactions and machine vision-based droplet motion control. It is expected that digital microfluidics-based machine vision system will add intelligence and automation to high-throughput biological imaging in the future.

Dual-nozzle microfluidic droplet generator

NASA Astrophysics Data System (ADS)

Choi, Ji Wook; Lee, Jong Min; Kim, Tae Hyun; Ha, Jang Ho; Ahrberg, Christian D.; Chung, Bong Geun

2018-05-01

The droplet-generating microfluidics has become an important technique for a variety of applications ranging from single cell analysis to nanoparticle synthesis. Although there are a large number of methods for generating and experimenting with droplets on microfluidic devices, the dispensing of droplets from these microfluidic devices is a challenge due to aggregation and merging of droplets at the interface of microfluidic devices. Here, we present a microfluidic dual-nozzle device for the generation and dispensing of uniform-sized droplets. The first nozzle of the microfluidic device is used for the generation of the droplets, while the second nozzle can accelerate the droplets and increase the spacing between them, allowing for facile dispensing of droplets. Computational fluid dynamic simulations were conducted to optimize the design parameters of the microfluidic device.

Note: Toward multiple addressable optical trapping

PubMed Central

Faustov, Alexei R.; Webb, Michael R.; Walt, David R.

2010-01-01

We describe a setup for addressable optical trapping in which a laser source is focused on a digital micromirror device and generates an optical trap in a microfluidic cell. In this paper, we report a proof-of-principle single beam∕single micromirror∕single three-dimensional trap arrangement that should serve as the basis for a multiple-trap instrument. PMID:20192526

Micro-chemical synthesis of molecular probes on an electronic microfluidic device

PubMed Central

Keng, Pei Yuin; Chen, Supin; Ding, Huijiang; Sadeghi, Saman; Shah, Gaurav J.; Dooraghi, Alex; Phelps, Michael E.; Satyamurthy, Nagichettiar; Chatziioannou, Arion F.; Kim, Chang-Jin “CJ”; van Dam, R. Michael

2012-01-01

We have developed an all-electronic digital microfluidic device for microscale chemical synthesis in organic solvents, operated by electrowetting-on-dielectric (EWOD). As an example of the principles, we demonstrate the multistep synthesis of [18F]FDG, the most common radiotracer for positron emission tomography (PET), with high and reliable radio-fluorination efficiency of [18F]FTAG (88 ± 7%, n = 11) and quantitative hydrolysis to [18F]FDG (> 95%, n = 11). We furthermore show that batches of purified [18F]FDG can successfully be used for PET imaging in mice and that they pass typical quality control requirements for human use (including radiochemical purity, residual solvents, Kryptofix, chemical purity, and pH). We report statistical repeatability of the radiosynthesis rather than best-case results, demonstrating the robustness of the EWOD microfluidic platform. Exhibiting high compatibility with organic solvents and the ability to carry out sophisticated actuation and sensing of reaction droplets, EWOD is a unique platform for performing diverse microscale chemical syntheses in small volumes, including multistep processes with intermediate solvent-exchange steps. PMID:22210110

ELISA-type assays of trace biomarkers using microfluidic methods.

PubMed

Dong, Jinhua; Ueda, Hiroshi

2017-09-01

Recently, great progress has been achieved for analytical technologies for biological substances. Traditionally, detection methods for analytes mainly rely on large instrumental analyses. These methods require costly equipment, skilled operators and long measurement time despite their generally low sensitivity. In contrast, immunoassays are becoming more and more popular for it is powerful, inexpensive, and convenient nature. Immunoassay has a range of applications, because it employs antibody, a protein produced by plasma cells in the acquired immune system to identify and neutralize diverse pathogens and other exogenous substances. However, the sensitivity of conventional immunoassays so far is limited by their reaction principles and detection methods. The microfluidics technology is the one that manipulates small volumes of fluid and flow, which has the potential to miniaturize many laboratory procedures. Immunoassays on microfluidic devices have been studied extensively and have gained significant attention owing to intrinsic advantages offered by the assay platforms. The techniques have allowed the miniaturization of conventional immunoassay and bring the advantages such as small volumes of samples and reagents as well as the decrease of contamination, which results in the decline of false-positive results. Ultimately, the combination of immunoassays with microfluidics affords a promising platform for multiple, sensitive, and automatic point-of-care diagnostics. Recent achievements on microfluidic devices and immunoassay detection systems including digital assay employing single molecule will be introduced in detail and the strategies for faster and more sensitive configurations in microfluidic immunosensors will be highlighted. WIREs Nanomed Nanobiotechnol 2017, 9:e1457. doi: 10.1002/wnan.1457 For further resources related to this article, please visit the WIREs website. © 2017 Wiley Periodicals, Inc.

Recent developments in microfluidics-based chemotaxis studies.

PubMed

Wu, Jiandong; Wu, Xun; Lin, Francis

2013-07-07

Microfluidic devices can better control cellular microenvironments compared to conventional cell migration assays. Over the past few years, microfluidics-based chemotaxis studies showed a rapid growth. New strategies were developed to explore cell migration in manipulated chemical gradients. In addition to expanding the use of microfluidic devices for a broader range of cell types, microfluidic devices were used to study cell migration and chemotaxis in complex environments. Furthermore, high-throughput microfluidic chemotaxis devices and integrated microfluidic chemotaxis systems were developed for medical and commercial applications. In this article, we review recent developments in microfluidics-based chemotaxis studies and discuss the new trends in this field observed over the past few years.

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

PubMed

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

2015-01-07

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

Floating Droplet Array: An Ultrahigh-Throughput Device for Droplet Trapping, Real-time Analysis and Recovery

PubMed Central

Labanieh, Louai; Nguyen, Thi N.; Zhao, Weian; Kang, Dong-Ku

2016-01-01

We describe the design, fabrication and use of a dual-layered microfluidic device for ultrahigh-throughput droplet trapping, analysis, and recovery using droplet buoyancy. To demonstrate the utility of this device for digital quantification of analytes, we quantify the number of droplets, which contain a β-galactosidase-conjugated bead among more than 100,000 immobilized droplets. In addition, we demonstrate that this device can be used for droplet clustering and real-time analysis by clustering several droplets together into microwells and monitoring diffusion of fluorescein, a product of the enzymatic reaction of β-galactosidase and its fluorogenic substrate FDG, between droplets. PMID:27134760

Applications of everyday IT and communications devices in modern analytical chemistry: A review.

PubMed

Grudpan, Kate; Kolev, Spas D; Lapanantnopakhun, Somchai; McKelvie, Ian D; Wongwilai, Wasin

2015-05-01

This paper reviews the development and recent use of everyday communications and IT equipment (mobile phones, digital cameras, scanners, webcams, etc) as detection devices for colorimetric chemistries. Such devices can readily be applied for visible detection using reaction formats such as microfluidic paper based analytical devices (µPADs), indicator papers, and well plate reaction vessels. Their use is highly advantageous with respect to cost, simplicity and portability, and offers many opportunities in the areas of point of care diagnosis, and at-site monitoring of environmental, agricultural, food and beverage parameters. Copyright © 2015 Elsevier B.V. All rights reserved.

Electronic drop sensing in microfluidic devices: automated operation of a nanoliter viscometer

PubMed Central

Srivastava, Nimisha; Burns, Mark A.

2007-01-01

We describe three droplet sensing techniques: a digital electrode, an analog electrode, and a thermal method. All three techniques use a single layer of metal lines that is easy to microfabricate and an electronic signal can be produced using low DC voltages. While the electrode methods utilize changes in electrical conductivity when the air/liquid interface of the droplet passes over a pair of electrodes, the thermal method is based on convective heat loss from a locally heated region. For the electrode method, the analog technique is able to detect 25 nL droplets while the digital technique is capable of detecting droplets as small as 100 pL. For thermal sensing, temperature profiles in the range of 36 °C and higher were used. Finally, we have used the digital electrode method and an array of electrodes located at preset distances to automate the operation of a previously described microfluidic viscometer. The viscometer is completely controlled by a laptop computer, and the total time for operation including setup, calibration, sample addition and viscosity calculation is approximately 4 minutes. PMID:16738725

Microfluidic Biochip Design

NASA Technical Reports Server (NTRS)

Panzarella, Charles

2004-01-01

As humans prepare for the exploration of our solar system, there is a growing need for miniaturized medical and environmental diagnostic devices for use on spacecrafts, especially during long-duration space missions where size and power requirements are critical. In recent years, the biochip (or Lab-on-a- Chip) has emerged as a technology that might be able to satisfy this need. In generic terms, a biochip is a miniaturized microfluidic device analogous to the electronic microchip that ushered in the digital age. It consists of tiny microfluidic channels, pumps and valves that transport small amounts of sample fluids to biosensors that can perform a variety of tests on those fluids in near real time. It has the obvious advantages of being small, lightweight, requiring less sample fluids and reagents and being more sensitive and efficient than larger devices currently in use. Some of the desired space-based applications would be to provide smaller, more robust devices for analyzing blood, saliva and urine and for testing water and food supplies for the presence of harmful contaminants and microorganisms. Our group has undertaken the goal of adapting as well as improving upon current biochip technology for use in long-duration microgravity environments. In addition to developing computational models of the microfluidic channels, valves and pumps that form the basis of every biochip, we are also trying to identify potential problems that could arise in reduced gravity and develop solutions to these problems. One such problem is due to the prevalence of bubbly sample fluids in microgravity. A bubble trapped in a microfluidic channel could be detrimental to the operation of a biochip. Therefore, the process of bubble formation in microgravity needs to be studied, and a model of this process has been developed and used to understand how bubbles develop and move through biochip components. It is clear that some type of bubble filter would be necessary in Space, and several bubble filter designs are being evaluated.

Bio-microfluidics: biomaterials and biomimetic designs.

PubMed

Domachuk, Peter; Tsioris, Konstantinos; Omenetto, Fiorenzo G; Kaplan, David L

2010-01-12

Bio-microfluidics applies biomaterials and biologically inspired structural designs (biomimetics) to microfluidic devices. Microfluidics, the techniques for constraining fluids on the micrometer and sub-micrometer scale, offer applications ranging from lab-on-a-chip to optofluidics. Despite this wealth of applications, the design of typical microfluidic devices imparts relatively simple, laminar behavior on fluids and is realized using materials and techniques from silicon planar fabrication. On the other hand, highly complex microfluidic behavior is commonplace in nature, where fluids with nonlinear rheology flow through chaotic vasculature composed from a range of biopolymers. In this Review, the current state of bio-microfluidic materials, designs and applications are examined. Biopolymers enable bio-microfluidic devices with versatile functionalization chemistries, flexibility in fabrication, and biocompatibility in vitro and in vivo. Polymeric materials such as alginate, collagen, chitosan, and silk are being explored as bulk and film materials for bio-microfluidics. Hydrogels offer options for mechanically functional devices for microfluidic systems such as self-regulating valves, microlens arrays and drug release systems, vital for integrated bio-microfluidic devices. These devices including growth factor gradients to study cell responses, blood analysis, biomimetic capillary designs, and blood vessel tissue culture systems, as some recent examples of inroads in the field that should lead the way in a new generation of microfluidic devices for bio-related needs and applications. Perhaps one of the most intriguing directions for the future will be fully implantable microfluidic devices that will also integrate with existing vasculature and slowly degrade to fully recapitulate native tissue structure and function, yet serve critical interim functions, such as tissue maintenance, drug release, mechanical support, and cell delivery.

A computational approach to real-time image processing for serial time-encoded amplified microscopy

NASA Astrophysics Data System (ADS)

Oikawa, Minoru; Hiyama, Daisuke; Hirayama, Ryuji; Hasegawa, Satoki; Endo, Yutaka; Sugie, Takahisa; Tsumura, Norimichi; Kuroshima, Mai; Maki, Masanori; Okada, Genki; Lei, Cheng; Ozeki, Yasuyuki; Goda, Keisuke; Shimobaba, Tomoyoshi

2016-03-01

High-speed imaging is an indispensable technique, particularly for identifying or analyzing fast-moving objects. The serial time-encoded amplified microscopy (STEAM) technique was proposed to enable us to capture images with a frame rate 1,000 times faster than using conventional methods such as CCD (charge-coupled device) cameras. The application of this high-speed STEAM imaging technique to a real-time system, such as flow cytometry for a cell-sorting system, requires successively processing a large number of captured images with high throughput in real time. We are now developing a high-speed flow cytometer system including a STEAM camera. In this paper, we describe our approach to processing these large amounts of image data in real time. We use an analog-to-digital converter that has up to 7.0G samples/s and 8-bit resolution for capturing the output voltage signal that involves grayscale images from the STEAM camera. Therefore the direct data output from the STEAM camera generates 7.0G byte/s continuously. We provided a field-programmable gate array (FPGA) device as a digital signal pre-processor for image reconstruction and finding objects in a microfluidic channel with high data rates in real time. We also utilized graphics processing unit (GPU) devices for accelerating the calculation speed of identification of the reconstructed images. We built our prototype system, which including a STEAM camera, a FPGA device and a GPU device, and evaluated its performance in real-time identification of small particles (beads), as virtual biological cells, owing through a microfluidic channel.

Magnet-assisted device-level alignment for the fabrication of membrane-sandwiched polydimethylsiloxane microfluidic devices

NASA Astrophysics Data System (ADS)

Lu, J.-C.; Liao, W.-H.; Tung, Y.-C.

2012-07-01

Polydimethylsiloxane (PDMS) microfluidic device is one of the most essential techniques that advance microfluidics research in recent decades. PDMS is broadly exploited to construct microfluidic devices due to its unique and advantageous material properties. To realize more functionalities, PDMS microfluidic devices with multi-layer architectures, especially those with sandwiched membranes, have been developed for various applications. However, existing alignment methods for device fabrication are mainly based on manual observations, which are time consuming, inaccurate and inconsistent. This paper develops a magnet-assisted alignment method to enhance device-level alignment accuracy and precision without complicated fabrication processes. In the developed alignment method, magnets are embedded into PDMS layers at the corners of the device. The paired magnets are arranged in symmetric positions at each PDMS layer, and the magnetic attraction force automatically pulls the PDMS layers into the aligned position during assembly. This paper also applies the method to construct a practical microfluidic device, a tunable chaotic micromixer. The results demonstrate the successful operation of the device without failure, which suggests the accurate alignment and reliable bonding achieved by the method. Consequently, the fabrication method developed in this paper is promising to be exploited to construct various membrane-sandwiched PDMS microfluidic devices with more integrated functionalities to advance microfluidics research.

3D printed conformal microfluidics for isolation and profiling of biomarkers from whole organs.

PubMed

Singh, Manjot; Tong, Yuxin; Webster, Kelly; Cesewski, Ellen; Haring, Alexander P; Laheri, Sahil; Carswell, Bill; O'Brien, Timothy J; Aardema, Charles H; Senger, Ryan S; Robertson, John L; Johnson, Blake N

2017-07-25

The ability to interface microfluidic devices with native complex biological architectures, such as whole organs, has the potential to shift the paradigm for the study and analysis of biological tissue. Here, we show 3D printing can be used to fabricate bio-inspired conformal microfluidic devices that directly interface with the surface of whole organs. Structured-light scanning techniques enabled the 3D topographical matching of microfluidic device geometry to porcine kidney anatomy. Our studies show molecular species are spontaneously transferred from the organ cortex to the conformal microfluidic device in the presence of fluid flow through the organ-conforming microchannel. Large animal studies using porcine kidneys (n = 32 organs) revealed the profile of molecular species in the organ-conforming microfluidic stream was dependent on the organ preservation conditions. Enzyme-linked immunosorbent assay (ELISA) studies revealed conformal microfluidic devices isolate clinically relevant metabolic and pathophysiological biomarkers from whole organs, including heat shock protein 70 (HSP-70) and kidney injury molecule-1 (KIM-1), which were detected in the microfluidic device as high as 409 and 12 pg mL -1 , respectively. Overall, these results show conformal microfluidic devices enable a novel minimally invasive 'microfluidic biopsy' technique for isolation and profiling of biomarkers from whole organs within a clinically relevant interval. This achievement could shift the paradigm for whole organ preservation and assessment, thereby helping to relieve the organ shortage crisis through increased availability and quality of donor organs. Ultimately, this work provides a major advance in microfluidics through the design and manufacturing of organ-conforming microfluidic devices and a novel technique for microfluidic-based analysis of whole organs.

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

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

2016-04-14

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.

Rapid prototyping of 2D glass microfluidic devices based on femtosecond laser assisted selective etching process

NASA Astrophysics Data System (ADS)

Kim, Sung-Il; Kim, Jeongtae; Koo, Chiwan; Joung, Yeun-Ho; Choi, Jiyeon

2018-02-01

Microfluidics technology which deals with small liquid samples and reagents within micro-scale channels has been widely applied in various aspects of biological, chemical, and life-scientific research. For fabricating microfluidic devices, a silicon-based polymer, PDMS (Polydimethylsiloxane), is widely used in soft lithography, but it has several drawbacks for microfluidic applications. Glass has many advantages over PDMS due to its excellent optical, chemical, and mechanical properties. However, difficulties in fabrication of glass microfluidic devices that requires multiple skilled steps such as MEMS technology taking several hours to days, impedes broad application of glass based devices. Here, we demonstrate a rapid and optical prototyping of a glass microfluidic device by using femtosecond laser assisted selective etching (LASE) and femtosecond laser welding. A microfluidic droplet generator was fabricated as a demonstration of a microfluidic device using our proposed prototyping. The fabrication time of a single glass chip containing few centimeter long and complex-shaped microfluidic channels was drastically reduced in an hour with the proposed laser based rapid and simple glass micromachining and hermetic packaging technique.

Generation of digitized microfluidic filling flow by vent control.

PubMed

Yoon, Junghyo; Lee, Eundoo; Kim, Jaehoon; Han, Sewoon; Chung, Seok

2017-06-15

Quantitative microfluidic point-of-care testing has been translated into clinical applications to support a prompt decision on patient treatment. A nanointerstice-driven filling technique has been developed to realize the fast and robust filling of microfluidic channels with liquid samples, but it has failed to provide a consistent filling time owing to the wide variation in liquid viscosity, resulting in an increase in quantification errors. There is a strong demand for simple and quick flow control to ensure accurate quantification, without a serious increase in system complexity. A new control mechanism employing two-beam refraction and one solenoid valve was developed and found to successfully generate digitized filling flow, completely free from errors due to changes in viscosity. The validity of digitized filling flow was evaluated by the immunoassay, using liquids with a wide range of viscosity. This digitized microfluidic filling flow is a novel approach that could be applied in conventional microfluidic point-of-care testing. Copyright © 2016 Elsevier B.V. All rights reserved.

Ultrasensitive microfluidic solid-phase ELISA using an actuatable microwell-patterned PDMS chip.

PubMed

Wang, Tanyu; Zhang, Mohan; Dreher, Dakota D; Zeng, Yong

2013-11-07

Quantitative detection of low abundance proteins is of significant interest for biological and clinical applications. Here we report an integrated microfluidic solid-phase ELISA platform for rapid and ultrasensitive detection of proteins with a wide dynamic range. Compared to the existing microfluidic devices that perform affinity capture and enzyme-based optical detection in a constant channel volume, the key novelty of our design is two-fold. First, our system integrates a microwell-patterned assay chamber that can be pneumatically actuated to significantly reduce the volume of chemifluorescent reaction, markedly improving the sensitivity and speed of ELISA. Second, monolithic integration of on-chip pumps and the actuatable assay chamber allow programmable fluid delivery and effective mixing for rapid and sensitive immunoassays. Ultrasensitive microfluidic ELISA was demonstrated for insulin-like growth factor 1 receptor (IGF-1R) across at least five orders of magnitude with an extremely low detection limit of 21.8 aM. The microwell-based solid-phase ELISA strategy provides an expandable platform for developing the next-generation microfluidic immunoassay systems that integrate and automate digital and analog measurements to further improve the sensitivity, dynamic ranges, and reproducibility of proteomic analysis.

Principles, Techniques, and Applications of Tissue Microfluidics

NASA Technical Reports Server (NTRS)

Wade, Lawrence A.; Kartalov, Emil P.; Shibata, Darryl; Taylor, Clive

2011-01-01

The principle of tissue microfluidics and its resultant techniques has been applied to cell analysis. Building microfluidics to suit a particular tissue sample would allow the rapid, reliable, inexpensive, highly parallelized, selective extraction of chosen regions of tissue for purposes of further biochemical analysis. Furthermore, the applicability of the techniques ranges beyond the described pathology application. For example, they would also allow the posing and successful answering of new sets of questions in many areas of fundamental research. The proposed integration of microfluidic techniques and tissue slice samples is called tissue microfluidics because it molds the microfluidic architectures in accordance with each particular structure of each specific tissue sample. Thus, microfluidics can be built around the tissues, following the tissue structure, or alternatively, the microfluidics can be adapted to the specific geometry of particular tissues. By contrast, the traditional approach is that microfluidic devices are structured in accordance with engineering considerations, while the biological components in applied devices are forced to comply with these engineering presets. The proposed principles represent a paradigm shift in microfluidic technology in three important ways: Microfluidic devices are to be directly integrated with, onto, or around tissue samples, in contrast to the conventional method of off-chip sample extraction followed by sample insertion in microfluidic devices. Architectural and operational principles of microfluidic devices are to be subordinated to suit specific tissue structure and needs, in contrast to the conventional method of building devices according to fluidic function alone and without regard to tissue structure. Sample acquisition from tissue is to be performed on-chip and is to be integrated with the diagnostic measurement within the same device, in contrast to the conventional method of off-chip sample prep and subsequent insertion into a diagnostic device. A more advanced form of tissue integration with microfluidics is tissue encapsulation, wherein the sample is completely encapsulated within a microfluidic device, to allow for full surface access. The immediate applications of these approaches lie with diagnostics of tissue slices and biopsy samples e.g. for cancer but the approaches would also be very useful in comparative genomics and other areas of fundamental research involving heterogeneous tissue samples.

Particle-Based Microfluidic Device for Providing High Magnetic Field Gradients

NASA Technical Reports Server (NTRS)

Wong, Tak S. (Inventor); Lin, Adam Y. (Inventor)

2013-01-01

A microfluidic device for manipulating particles in a fluid has a device body that defines a main channel therein, in which the main channel has an inlet and an outlet. The device body further defines a particulate diverting channel therein, the particulate diverting channel being in fluid connection with the main channel between the inlet and the outlet of the main channel and having a particulate outlet. The microfluidic device also has a plurality of microparticles arranged proximate or in the main channel between the inlet of the main channel and the fluid connection of the particulate diverting channel to the main channel. The plurality of microparticles each comprises a material in a composition thereof having a magnetic susceptibility suitable to cause concentration of magnetic field lines of an applied magnetic field while in operation. A microfluidic particle-manipulation system has a microfluidic particle-manipulation device and a magnet disposed proximate the microfluidic particle-manipulation device.

Digital PCR provides absolute quantitation of viral load for an occult RNA virus.

PubMed

White, Richard Allen; Quake, Stephen R; Curr, Kenneth

2012-01-01

Using a multiplexed LNA-based Taqman assay, RT-digital PCR (RT-dPCR) was performed in a prefabricated microfluidic device that monitored absolute viral load in native and immortalized cell lines, overall precision of detection, and the absolute detection limit of an occult RNA virus GB Virus Type C (GBV-C). RT-dPCR had on average a 10% lower overall coefficient of variation (CV, a measurement of precision) for viral load testing than RT-qPCR and had a higher overall detection limit, able to quantify as low as three 5'-UTR molecules of GBV-C genome. Two commercial high-yield in vitro transcription kits (T7 Ribomax Express by Promega and Ampliscribe T7 Flash by Epicentre) were compared to amplify GBV-C RNA genome with T7-mediated amplification. The Ampliscribe T7 Flash outperformed the T7 Ribomax Express in yield of full-length GBV-C RNA genome. THP-1 cells (a model of monocytic derived cells) were transfected with GBV-C, yielding infectious virions that replicated over a 120h time course and could be infected directly. This study provides the first evidence of GBV-C replication in monocytic derived clonal cells. Thus far, it is the only study using a microfluidic device that measures directly viral load of mammalian RNA virus in a digital format without need for a standard curve. Copyright © 2011 Elsevier B.V. All rights reserved.

Single cell digital polymerase chain reaction on self-priming compartmentalization chip

PubMed Central

Zhu, Qiangyuan; Qiu, Lin; Xu, Yanan; Li, Guang; Mu, Ying

2017-01-01

Single cell analysis provides a new framework for understanding biology and disease, however, an absolute quantification of single cell gene expression still faces many challenges. Microfluidic digital polymerase chain reaction (PCR) provides a unique method to absolutely quantify the single cell gene expression, but only limited devices are developed to analyze a single cell with detection variation. This paper describes a self-priming compartmentalization (SPC) microfluidic digital polymerase chain reaction chip being capable of performing single molecule amplification from single cell. The chip can be used to detect four single cells simultaneously with 85% of sample digitization. With the optimized protocol for the SPC chip, we first tested the ability, precision, and sensitivity of our SPC digital PCR chip by assessing β-actin DNA gene expression in 1, 10, 100, and 1000 cells. And the reproducibility of the SPC chip is evaluated by testing 18S rRNA of single cells with 1.6%–4.6% of coefficient of variation. At last, by detecting the lung cancer related genes, PLAU gene expression of A549 cells at the single cell level, the single cell heterogeneity was demonstrated. So, with the power-free, valve-free SPC chip, the gene copy number of single cells can be quantified absolutely with higher sensitivity, reduced labor time, and reagent. We expect that this chip will enable new studies for biology and disease. PMID:28191267

Single cell digital polymerase chain reaction on self-priming compartmentalization chip.

PubMed

Zhu, Qiangyuan; Qiu, Lin; Xu, Yanan; Li, Guang; Mu, Ying

2017-01-01

Single cell analysis provides a new framework for understanding biology and disease, however, an absolute quantification of single cell gene expression still faces many challenges. Microfluidic digital polymerase chain reaction (PCR) provides a unique method to absolutely quantify the single cell gene expression, but only limited devices are developed to analyze a single cell with detection variation. This paper describes a self-priming compartmentalization (SPC) microfluidic digital polymerase chain reaction chip being capable of performing single molecule amplification from single cell. The chip can be used to detect four single cells simultaneously with 85% of sample digitization. With the optimized protocol for the SPC chip, we first tested the ability, precision, and sensitivity of our SPC digital PCR chip by assessing β-actin DNA gene expression in 1, 10, 100, and 1000 cells. And the reproducibility of the SPC chip is evaluated by testing 18S rRNA of single cells with 1.6%-4.6% of coefficient of variation. At last, by detecting the lung cancer related genes, PLAU gene expression of A549 cells at the single cell level, the single cell heterogeneity was demonstrated. So, with the power-free, valve-free SPC chip, the gene copy number of single cells can be quantified absolutely with higher sensitivity, reduced labor time, and reagent. We expect that this chip will enable new studies for biology and disease.

Printing-based fabrication method using sacrificial paper substrates for flexible and wearable microfluidic devices

NASA Astrophysics Data System (ADS)

Chung, Daehan; Gray, Bonnie L.

2017-11-01

We present a simple, fast, and inexpensive new printing-based fabrication process for flexible and wearable microfluidic channels and devices. Microfluidic devices are fabricated on textiles (fabric) for applications in clothing-based wearable microfluidic sensors and systems. The wearable and flexible microfluidic devices are comprised of water-insoluable screen-printable plastisol polymer. Sheets of paper are used as sacrificial substrates for multiple layers of polymer on the fabric’s surface. Microfluidic devices can be made within a short time using simple processes and inexpensive equipment that includes a laser cutter and a thermal laminator. The fabrication process is characterized to demonstrate control of microfluidic channel thickness and width. Film thickness smaller than 100 micrometers and lateral dimensions smaller than 150 micrometers are demonstrated. A flexible microfluidic mixer is also developed on fabric and successfully tested on both flat and curved surfaces at volumetric flow rates ranging from 5.5-46 ml min-1.

Novel application of digital microfluidics for the detection of biotinidase deficiency in newborns.

PubMed

Graham, Carrie; Sista, Ramakrishna S; Kleinert, Jairus; Wu, Ning; Eckhardt, Allen; Bali, Deeksha; Millington, David S; Pamula, Vamsee K

2013-12-01

Newborn screening for biotinidase deficiency can be performed using a fluorometric enzyme assay on dried blood spot specimens. As a pre-requisite to the consolidation of different enzymatic assays onto a single platform, we describe here a novel analytical method for detecting biotinidase deficiency using the same digital microfluidic cartridge that has already been demonstrated to screen for five lysosomal storage diseases (Pompe, Fabry, Gaucher, Hurler and Hunter) in a multiplex format. A novel assay to quantify biotinidase concentration in dried blood spots (DBS) was developed and optimized on the digital microfluidic platform using proficiency testing samples from the Centers for Disease Control and Prevention. The enzymatic assay uses 4-methylumbelliferyl biotin as the fluorogenic substrate. Biotinidase deficiency assays were performed on normal (n=200) and deficient (n=7) newborn DBS specimens. Enzymatic activity analysis of biotinidase deficiency revealed distinct separation between normal and affected DBS specimens using digital microfluidics and these results matched the expected activity. This study has demonstrated performance of biotinidase deficiency assays by measurement of 4-methylumbelliferyl product on a digital microfluidic platform. Due to the inherent ease in multiplexing on such a platform, consolidation of other fluorometric assays onto a single cartridge may be realized. © 2013.

Simple and Versatile 3D Printed Microfluidics Using Fused Filament Fabrication.

PubMed

Morgan, Alex J L; Hidalgo San Jose, Lorena; Jamieson, William D; Wymant, Jennifer M; Song, Bing; Stephens, Phil; Barrow, David A; Castell, Oliver K

2016-01-01

The uptake of microfluidics by the wider scientific community has been limited by the fabrication barrier created by the skills and equipment required for the production of traditional microfluidic devices. Here we present simple 3D printed microfluidic devices using an inexpensive and readily accessible printer with commercially available printer materials. We demonstrate that previously reported limitations of transparency and fidelity have been overcome, whilst devices capable of operating at pressures in excess of 2000 kPa illustrate that leakage issues have also been resolved. The utility of the 3D printed microfluidic devices is illustrated by encapsulating dental pulp stem cells within alginate droplets; cell viability assays show the vast majority of cells remain live, and device transparency is sufficient for single cell imaging. The accessibility of these devices is further enhanced through fabrication of integrated ports and by the introduction of a Lego®-like modular system facilitating rapid prototyping whilst offering the potential for novices to build microfluidic systems from a database of microfluidic components.

Simple and Versatile 3D Printed Microfluidics Using Fused Filament Fabrication

PubMed Central

Morgan, Alex J. L.; Hidalgo San Jose, Lorena; Jamieson, William D.; Wymant, Jennifer M.; Song, Bing; Stephens, Phil

2016-01-01

The uptake of microfluidics by the wider scientific community has been limited by the fabrication barrier created by the skills and equipment required for the production of traditional microfluidic devices. Here we present simple 3D printed microfluidic devices using an inexpensive and readily accessible printer with commercially available printer materials. We demonstrate that previously reported limitations of transparency and fidelity have been overcome, whilst devices capable of operating at pressures in excess of 2000 kPa illustrate that leakage issues have also been resolved. The utility of the 3D printed microfluidic devices is illustrated by encapsulating dental pulp stem cells within alginate droplets; cell viability assays show the vast majority of cells remain live, and device transparency is sufficient for single cell imaging. The accessibility of these devices is further enhanced through fabrication of integrated ports and by the introduction of a Lego®-like modular system facilitating rapid prototyping whilst offering the potential for novices to build microfluidic systems from a database of microfluidic components. PMID:27050661

High-throughput microfluidic single-cell digital polymerase chain reaction.

PubMed

White, A K; Heyries, K A; Doolin, C; Vaninsberghe, M; Hansen, C L

2013-08-06

Here we present an integrated microfluidic device for the high-throughput digital polymerase chain reaction (dPCR) analysis of single cells. This device allows for the parallel processing of single cells and executes all steps of analysis, including cell capture, washing, lysis, reverse transcription, and dPCR analysis. The cDNA from each single cell is distributed into a dedicated dPCR array consisting of 1020 chambers, each having a volume of 25 pL, using surface-tension-based sample partitioning. The high density of this dPCR format (118,900 chambers/cm(2)) allows the analysis of 200 single cells per run, for a total of 204,000 PCR reactions using a device footprint of 10 cm(2). Experiments using RNA dilutions show this device achieves shot-noise-limited performance in quantifying single molecules, with a dynamic range of 10(4). We performed over 1200 single-cell measurements, demonstrating the use of this platform in the absolute quantification of both high- and low-abundance mRNA transcripts, as well as micro-RNAs that are not easily measured using alternative hybridization methods. We further apply the specificity and sensitivity of single-cell dPCR to performing measurements of RNA editing events in single cells. High-throughput dPCR provides a new tool in the arsenal of single-cell analysis methods, with a unique combination of speed, precision, sensitivity, and specificity. We anticipate this approach will enable new studies where high-performance single-cell measurements are essential, including the analysis of transcriptional noise, allelic imbalance, and RNA processing.

A Low-Noise Transimpedance Amplifier for BLM-Based Ion Channel Recording.

PubMed

Crescentini, Marco; Bennati, Marco; Saha, Shimul Chandra; Ivica, Josip; de Planque, Maurits; Morgan, Hywel; Tartagni, Marco

2016-05-19

High-throughput screening (HTS) using ion channel recording is a powerful drug discovery technique in pharmacology. Ion channel recording with planar bilayer lipid membranes (BLM) is scalable and has very high sensitivity. A HTS system based on BLM ion channel recording faces three main challenges: (i) design of scalable microfluidic devices; (ii) design of compact ultra-low-noise transimpedance amplifiers able to detect currents in the pA range with bandwidth >10 kHz; (iii) design of compact, robust and scalable systems that integrate these two elements. This paper presents a low-noise transimpedance amplifier with integrated A/D conversion realized in CMOS 0.35 μm technology. The CMOS amplifier acquires currents in the range ±200 pA and ±20 nA, with 100 kHz bandwidth while dissipating 41 mW. An integrated digital offset compensation loop balances any voltage offsets from Ag/AgCl electrodes. The measured open-input input-referred noise current is as low as 4 fA/√Hz at ±200 pA range. The current amplifier is embedded in an integrated platform, together with a microfluidic device, for current recording from ion channels. Gramicidin-A, α-haemolysin and KcsA potassium channels have been used to prove both the platform and the current-to-digital converter.

A Low-Noise Transimpedance Amplifier for BLM-Based Ion Channel Recording

PubMed Central

Crescentini, Marco; Bennati, Marco; Saha, Shimul Chandra; Ivica, Josip; de Planque, Maurits; Morgan, Hywel; Tartagni, Marco

2016-01-01

High-throughput screening (HTS) using ion channel recording is a powerful drug discovery technique in pharmacology. Ion channel recording with planar bilayer lipid membranes (BLM) is scalable and has very high sensitivity. A HTS system based on BLM ion channel recording faces three main challenges: (i) design of scalable microfluidic devices; (ii) design of compact ultra-low-noise transimpedance amplifiers able to detect currents in the pA range with bandwidth >10 kHz; (iii) design of compact, robust and scalable systems that integrate these two elements. This paper presents a low-noise transimpedance amplifier with integrated A/D conversion realized in CMOS 0.35 μm technology. The CMOS amplifier acquires currents in the range ±200 pA and ±20 nA, with 100 kHz bandwidth while dissipating 41 mW. An integrated digital offset compensation loop balances any voltage offsets from Ag/AgCl electrodes. The measured open-input input-referred noise current is as low as 4 fA/√Hz at ±200 pA range. The current amplifier is embedded in an integrated platform, together with a microfluidic device, for current recording from ion channels. Gramicidin-A, α-haemolysin and KcsA potassium channels have been used to prove both the platform and the current-to-digital converter. PMID:27213382

Building bio-assays with magnetic particles on a digital microfluidic platform.

PubMed

Kokalj, Tadej; Pérez-Ruiz, Elena; Lammertyn, Jeroen

2015-09-25

Digital microfluidics (DMF) has emerged as a promising liquid handling technology for a variety of applications, demonstrating great potential both in terms of miniaturization and automation. DMF is based on the manipulation of discrete, independently controllable liquid droplets, which makes it highly reconfigurable and reprogrammable. One of its most exclusive advantages, compared to microchannel-based microfluidics, is its ability to precisely handle solid nano- and microsized objects, such as magnetic particles. Magnetic particles have become very popular in the last decade, since their high surface-to-volume ratio and the possibility to magnetically separate them from the matrix make them perfect suitable as a solid support for bio-assay development. The potential of magnetic particles in DMF-based bio-assays has been demonstrated for various applications. In this review we discuss the latest developments of magnetic particle-based DMF bio-assays with the aim to present, identify and analyze the trends in the field. We also discuss the state-of-the art of device integration, current status of commercialization and issues that still need to be addressed. With this paper we intend to stimulate researchers to exploit and unveil the potential of these exciting tools, which will shape the future of modern biochemistry, microbiology and biomedical diagnostics. Copyright © 2015 Elsevier B.V. All rights reserved.

[Advances on enzymes and enzyme inhibitors research based on microfluidic devices].

PubMed

Hou, Feng-Hua; Ye, Jian-Qing; Chen, Zuan-Guang; Cheng, Zhi-Yi

2010-06-01

With the continuous development in microfluidic fabrication technology, microfluidic analysis has evolved from a concept to one of research frontiers in last twenty years. The research of enzymes and enzyme inhibitors based on microfluidic devices has also made great progress. Microfluidic technology improved greatly the analytical performance of the research of enzymes and enzyme inhibitors by reducing the consumption of reagents, decreasing the analysis time, and developing automation. This review focuses on the development and classification of enzymes and enzyme inhibitors research based on microfluidic devices.

Integrated chemical/biochemical sample collection, pre-concentration, and analysis on a digital microfluidic lab-on-a-chip platform

NASA Astrophysics Data System (ADS)

Fair, Richard B.; Khlystov, A.; Srinivasan, Vijay; Pamula, Vamsee K.; Weaver, Kathryn N.

2004-12-01

An ideal on-site chemical/biochemical analysis system must be inexpensive, sensitive, fully automated and integrated, reliable, and compatible with a broad range of samples. The advent of digital microfluidic lab-on-a-chip (LoC) technology offers such a detection system due to the advantages in portability, reduction of the volumes of the sample and reagents, faster analysis times, increased automation, low power consumption, compatibility with mass manufacturing, and high throughput. We describe progress towards integrating sample collection onto a digital microfluidic LoC that is a component of a cascade impactor device. The sample collection is performed by impacting airborne particles directly onto the surface of the chip. After the collection phase, the surface of the chip is washed with a micro-droplet of solvent. The droplet will be digitally directed across the impaction surface, dissolving sample constituents. Because of the very small droplet volume used for extraction of the sample from a wide colection area, the resulting solution is realatively concentrated and the analytes can be detected after a very short sampling time (1 min) due to such pre-concentration. After the washing phase, the droplet is mixed with specific reagents that produce colored reaction products. The concentration of the analyte is quantitatively determined by measuring absorption at target wavelengths using a simple light emitting diode and photodiode setup. Specific applications include automatic measurements of major inorganic ions in aerosols, such as sulfate, nitrate and ammonium, with a time resolution of 1 min and a detection limit of 30 nm/m3. We have already demonstrated the detection and quantification of nitroaromatic explosives without integrating the sample collection. Other applications being developed include airborne bioagent detection.

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

ERIC Educational Resources Information Center

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

2014-01-01

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

Advantages and challenges of microfluidic cell culture in polydimethylsiloxane devices.

PubMed

Halldorsson, Skarphedinn; Lucumi, Edinson; Gómez-Sjöberg, Rafael; Fleming, Ronan M T

2015-01-15

Culture of cells using various microfluidic devices is becoming more common within experimental cell biology. At the same time, a technological radiation of microfluidic cell culture device designs is currently in progress. Ultimately, the utility of microfluidic cell culture will be determined by its capacity to permit new insights into cellular function. Especially insights that would otherwise be difficult or impossible to obtain with macroscopic cell culture in traditional polystyrene dishes, flasks or well-plates. Many decades of heuristic optimization have gone into perfecting conventional cell culture devices and protocols. In comparison, even for the most commonly used microfluidic cell culture devices, such as those fabricated from polydimethylsiloxane (PDMS), collective understanding of the differences in cellular behavior between microfluidic and macroscopic culture is still developing. Moving in vitro culture from macroscopic culture to PDMS based devices can come with unforeseen challenges. Changes in device material, surface coating, cell number per unit surface area or per unit media volume may all affect the outcome of otherwise standard protocols. In this review, we outline some of the advantages and challenges that may accompany a transition from macroscopic to microfluidic cell culture. We focus on decisive factors that distinguish macroscopic from microfluidic cell culture to encourage a reconsideration of how macroscopic cell culture principles might apply to microfluidic cell culture. Copyright © 2014 The Authors. Published by Elsevier B.V. All rights reserved.

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

NASA Astrophysics Data System (ADS)

Li, Er Qiang; Zhang, Jia Ming; Thoroddsen, Sigurdur T.

2014-01-01

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

Micro-fluidic interconnect

DOEpatents

Okandan, Murat [Albuquerque, NM; Galambos, Paul C [Albuquerque, NM; Benavides, Gilbert L [Los Ranchos, NM; Hetherington, Dale L [Albuquerque, NM

2006-02-28

An apparatus for simultaneously aligning and interconnecting microfluidic ports is presented. Such interconnections are required to utilize microfluidic devices fabricated in Micro-Electromechanical-Systems (MEMS) technologies, that have multiple fluidic access ports (e.g. 100 micron diameter) within a small footprint, (e.g. 3 mm.times.6 mm). Fanout of the small ports of a microfluidic device to a larger diameter (e.g. 500 microns) facilitates packaging and interconnection of the microfluidic device to printed wiring boards, electronics packages, fluidic manifolds etc.

Digital Photonic Production of Micro Structures in Glass by In-Volume Selective Laser-Induced Etching using a High Speed Micro Scanner

NASA Astrophysics Data System (ADS)

Gottmann, Jens; Hermans, Martin; Ortmann, Jürgen

Digital photonic production of 3D microfluidic devices and assembled micro mechanics inside fused silica glass is carried out using ISLE directly from digital CAD data. To exploit the potential productivity of new high average power fs-lasers >150 W a modular high speed scanning system has been developed. Acousto-optical beam deflection, galvo-scanners and translation stages are controlled by CAM software. Using a lens with 10 mm focal length a focus radius of 1 μm is scanned with a velocity of 12 m/s on 400 μm track radius enabling the up-scaling of the ISLE- process using fs-laser radiation with up to 30 W.

An investigation of paper based microfluidic devices for size based separation and extraction applications.

PubMed

Zhong, Z W; Wu, R G; Wang, Z P; Tan, H L

2015-09-01

Conventional microfluidic devices are typically complex and expensive. The devices require the use of pneumatic control systems or highly precise pumps to control the flow in the devices. This work investigates an alternative method using paper based microfluidic devices to replace conventional microfluidic devices. Size based separation and extraction experiments conducted were able to separate free dye from a mixed protein and dye solution. Experimental results showed that pure fluorescein isothiocyanate could be separated from a solution of mixed fluorescein isothiocyanate and fluorescein isothiocyanate labeled bovine serum albumin. The analysis readings obtained from a spectrophotometer clearly show that the extracted tartrazine sample did not contain any amount of Blue-BSA, because its absorbance value was 0.000 measured at a wavelength of 590nm, which correlated to Blue-BSA. These demonstrate that paper based microfluidic devices, which are inexpensive and easy to implement, can potentially replace their conventional counterparts by the use of simple geometry designs and the capillary action. These findings will potentially help in future developments of paper based microfluidic devices. Copyright © 2015 Elsevier B.V. All rights reserved.

Microfluidics on compliant substrates: recent developments in foldable and bendable devices and system packaging

NASA Astrophysics Data System (ADS)

Gray, Bonnie L.

2012-04-01

Microfluidics is revolutionizing laboratory methods and biomedical devices, offering new capabilities and instrumentation in multiple areas such as DNA analysis, proteomics, enzymatic analysis, single cell analysis, immunology, point-of-care medicine, personalized medicine, drug delivery, and environmental toxin and pathogen detection. For many applications (e.g., wearable and implantable health monitors, drug delivery devices, and prosthetics) mechanically flexible polymer devices and systems that can conform to the body offer benefits that cannot be achieved using systems based on conventional rigid substrate materials. However, difficulties in implementing active devices and reliable packaging technologies have limited the success of flexible microfluidics. Employing highly compliant materials such as PDMS that are typically employed for prototyping, we review mechanically flexible polymer microfluidic technologies based on free-standing polymer substrates and novel electronic and microfluidic interconnection schemes. Central to these new technologies are hybrid microfabrication methods employing novel nanocomposite polymer materials and devices. We review microfabrication methods using these materials, along with demonstrations of example devices and packaging schemes that employ them. We review these recent developments and place them in the context of the fields of flexible microfluidics and conformable systems, and discuss cross-over applications to conventional rigid-substrate microfluidics.

Thermoplastic microfluidic devices and their applications in protein and DNA analysis

PubMed Central

Liu, Ke; Fan, Z. Hugh

2013-01-01

Microfluidics is a platform technology that has been used for genomics, proteomics, chemical synthesis, environment monitoring, cellular studies, and other applications. The fabrication materials of microfluidic devices have traditionally included silicon and glass, but plastics have gained increasing attention in the past few years. We focus this review on thermoplastic microfluidic devices and their applications in protein and DNA analysis. We outline the device design and fabrication methods, followed by discussion on the strategies of surface treatment. We then concentrate on several significant advancements in applying thermoplastic microfluidic devices to protein separation, immunoassays, and DNA analysis. Comparison among numerous efforts, as well as the discussion on the challenges and innovation associated with detection, is presented. PMID:21274478

OpenDrop: An Integrated Do-It-Yourself Platform for Personal Use of Biochips

PubMed Central

Alistar, Mirela; Gaudenz, Urs

2017-01-01

Biochips, or digital labs-on-chip, are developed with the purpose of being used by laboratory technicians or biologists in laboratories or clinics. In this article, we expand this vision with the goal of enabling everyone, regardless of their expertise, to use biochips for their own personal purposes. We developed OpenDrop, an integrated electromicrofluidic platform that allows users to develop and program their own bio-applications. We address the main challenges that users may encounter: accessibility, bio-protocol design and interaction with microfluidics. OpenDrop consists of a do-it-yourself biochip, an automated software tool with visual interface and a detailed technique for at-home operations of microfluidics. We report on two years of use of OpenDrop, released as an open-source platform. Our platform attracted a highly diverse user base with participants originating from maker communities, academia and industry. Our findings show that 47% of attempts to replicate OpenDrop were successful, the main challenge remaining the assembly of the device. In terms of usability, the users managed to operate their platforms at home and are working on designing their own bio-applications. Our work provides a step towards a future in which everyone will be able to create microfluidic devices for their personal applications, thereby democratizing parts of health care. PMID:28952524

Finite Element Model of Oxygen Transport for the Design of Geometrically Complex Microfluidic Devices Used in Biological Studies

PubMed Central

Fraser, Graham M.; Goldman, Daniel; Ellis, Christopher G.

2016-01-01

Red blood cells play a crucial role in the local regulation of oxygen supply in the microcirculation through the oxygen dependent release of ATP. Since red blood cells serve as an oxygen sensor for the circulatory system, the dynamics of ATP release determine the effectiveness of red blood cells to relate the oxygen levels to the vessels. Previous work has focused on the feasibility of developing a microfluidic system to measure the dynamics of ATP release. The objective was to determine if a steep oxygen gradient could be developed in the channel to cause a rapid decrease in hemoglobin oxygen saturation in order to measure the corresponding levels of ATP released from the red blood cells. In the present study, oxygen transport simulations were used to optimize the geometric design parameters for a similar system which is easier to fabricate. The system is composed of a microfluidic device stacked on top of a large, gas impermeable flow channel with a hole to allow gas exchange. The microfluidic device is fabricated using soft lithography in polydimethyl-siloxane, an oxygen permeable material. Our objective is twofold: (1) optimize the parameters of our system and (2) develop a method to assess the oxygen distribution in complex 3D microfluidic device geometries. 3D simulations of oxygen transport were performed to simulate oxygen distribution throughout the device. The simulations demonstrate that microfluidic device geometry plays a critical role in molecule exchange, for instance, changing the orientation of the short wide microfluidic channel results in a 97.17% increase in oxygen exchange. Since microfluidic devices have become a more prominent tool in biological studies, understanding the transport of oxygen and other biological molecules in microfluidic devices is critical for maintaining a physiologically relevant environment. We have also demonstrated a method to assess oxygen levels in geometrically complex microfluidic devices. PMID:27829071

Finite Element Model of Oxygen Transport for the Design of Geometrically Complex Microfluidic Devices Used in Biological Studies.

PubMed

Sové, Richard J; Fraser, Graham M; Goldman, Daniel; Ellis, Christopher G

2016-01-01

Red blood cells play a crucial role in the local regulation of oxygen supply in the microcirculation through the oxygen dependent release of ATP. Since red blood cells serve as an oxygen sensor for the circulatory system, the dynamics of ATP release determine the effectiveness of red blood cells to relate the oxygen levels to the vessels. Previous work has focused on the feasibility of developing a microfluidic system to measure the dynamics of ATP release. The objective was to determine if a steep oxygen gradient could be developed in the channel to cause a rapid decrease in hemoglobin oxygen saturation in order to measure the corresponding levels of ATP released from the red blood cells. In the present study, oxygen transport simulations were used to optimize the geometric design parameters for a similar system which is easier to fabricate. The system is composed of a microfluidic device stacked on top of a large, gas impermeable flow channel with a hole to allow gas exchange. The microfluidic device is fabricated using soft lithography in polydimethyl-siloxane, an oxygen permeable material. Our objective is twofold: (1) optimize the parameters of our system and (2) develop a method to assess the oxygen distribution in complex 3D microfluidic device geometries. 3D simulations of oxygen transport were performed to simulate oxygen distribution throughout the device. The simulations demonstrate that microfluidic device geometry plays a critical role in molecule exchange, for instance, changing the orientation of the short wide microfluidic channel results in a 97.17% increase in oxygen exchange. Since microfluidic devices have become a more prominent tool in biological studies, understanding the transport of oxygen and other biological molecules in microfluidic devices is critical for maintaining a physiologically relevant environment. We have also demonstrated a method to assess oxygen levels in geometrically complex microfluidic devices.

Point-of-Care Quantitative Measure of Glucose-6-Phosphate Dehydrogenase Enzyme Deficiency.

PubMed

Bhutani, Vinod K; Kaplan, Michael; Glader, Bertil; Cotten, Michael; Kleinert, Jairus; Pamula, Vamsee

2015-11-01

Widespread newborn screening on a point-of-care basis could prevent bilirubin neurotoxicity in newborns with glucose-6-phosphate dehydrogenase (G6PD) deficiency. We evaluated a quantitative G6PD assay on a digital microfluidic platform by comparing its performance with standard clinical methods. G6PD activity was measured quantitatively by using digital microfluidic fluorescence and the gold standard fluorescence biochemical test on a convenience sample of 98 discarded blood samples. Twenty-four samples were designated as G6PD deficient. Mean ± SD G6PD activity for normal samples using the digital microfluidic method and the standard method, respectively, was 9.7 ± 2.8 and 11.1 ± 3.0 U/g hemoglobin (Hb), respectively; for G6PD-deficient samples, it was 0.8 ± 0.7 and 1.4 ± 0.9 U/g Hb. Bland-Altman analysis determined a mean difference of -0.96 ± 1.8 U/g Hb between the digital microfluidic fluorescence results and the standard biochemical test results. The lower and upper limits for the digital microfluidic platform were 4.5 to 19.5 U/g Hb for normal samples and 0.2 to 3.7 U/g Hb for G6PD-deficient samples. The lower and upper limits for the Stanford method were 5.5 to 20.7 U/g Hb for normal samples and 0.1 to 2.8 U/g Hb for G6PD-deficient samples. The measured activity discriminated between G6PD-deficient samples and normal samples with no overlap. Pending further validation, a digital microfluidics platform could be an accurate point-of-care screening tool for rapid newborn G6PD screening. Copyright © 2015 by the American Academy of Pediatrics.

Microfluidics meets metabolomics to reveal the impact of Campylobacter jejuni infection on biochemical pathways.

PubMed

Mortensen, Ninell P; Mercier, Kelly A; McRitchie, Susan; Cavallo, Tammy B; Pathmasiri, Wimal; Stewart, Delisha; Sumner, Susan J

2016-06-01

Microfluidic devices that are currently being used in pharmaceutical research also have a significant potential for utilization in investigating exposure to infectious agents. We have established a microfluidic device cultured with Caco-2 cells, and utilized metabolomics to investigate the biochemical responses to the bacterial pathogen Campylobacter jejuni. In the microfluidic devices, Caco-2 cells polarize at day 5, are uniform, have defined brush borders and tight junctions, and form a mucus layer. Metabolomics analysis of cell culture media collected from both Caco-2 cell culture systems demonstrated a more metabolic homogenous biochemical profile in the media collected from microfluidic devices, compared with media collected from transwells. GeneGo pathway mapping indicated that aminoacyl-tRNA biosynthesis was perturbed by fluid flow, suggesting that fluid dynamics and shear stress impacts the cells translational quality control. Both microfluidic device and transwell culturing systems were used to investigate the impact of Campylobacter jejuni infection on biochemical processes. Caco-2 cells cultured in either system were infected at day 5 with C. jejuni 81-176 for 48 h. Metabolomics analysis clearly differentiated C. jejuni 81-176 infected and non-infected medias collected from the microfluidic devices, and demonstrated that C. jejuni 81-176 infection in microfluidic devices impacts branched-chain amino acid metabolism, glycolysis, and gluconeogenesis. In contrast, no distinction was seen in the biochemical profiles of infected versus non-infected media collected from cells cultured in transwells. Microfluidic culturing conditions demonstrated a more metabolically homogenous cell population, and present the opportunity for studying host-pathogen interactions for extended periods of time.

Microfluidics Meets Metabolomics to Reveal the Impact of Campylobacter jejuni Infection on Biochemical Pathways

PubMed Central

Mortensen, Ninell P.; Mercier, Kelly A.; McRitchie, Susan; Cavallo, Tammy B.; Pathmasiri, Wimal; Stewart, Delisha; Sumner, Susan J.

2016-01-01

Microfluidic devices that are currently being used in pharmaceutical research also have a significant potential for utilization in investigating exposure to infectious agents. We have established a microfluidic device cultured with Caco-2 cells, and utilized metabolomics to investigate the biochemical responses to the bacterial pathogen Campylobacter jejuni. In the microfluidic devices, Caco-2 cells polarize at day 5, are uniform, have defined brush borders and tight junctions, and form a mucus layer. Metabolomics analysis of cell culture media collected from both Caco-2 cell culture systems demonstrated a more metabolic homogenous biochemical profile in the media collected from microfluidic devices, compared with media collected from transwells. GeneGo pathway mapping indicated that aminoacyl-tRNA biosynthesis was perturbed by fluid flow, suggesting that fluid dynamics and shear stress impacts the cells translational quality control. Both microfluidic device and transwell culturing systems were used to investigate the impact of Campylobacter jejuni infection on biochemical processes. Caco-2 cells cultured in either system were infected at day 5 with C. jejuni 81-176 for 48 hours. Metabolomics analysis clearly differentiated C. jejuni 81-176 infected and non-infected medias collected from the microfluidic devices, and demonstrated that C. jejuni 81-176 infection in microfluidic devices impacts branched-chain amino acid metabolism, glycolysis, and gluconeogenesis. In contrast, no distinction was seen in the biochemical profiles of infected versus non-infected media collected from cells cultured in transwells. Microfluidic culturing conditions demonstrated a more metabolically homogenous cell population, and present the opportunity for studying host-pathogen interactions for extended periods of time. PMID:27231016

Development of a real-world direct interface for integrated DNA extraction and amplification in a microfluidic device.

PubMed

Shaw, Kirsty J; Joyce, Domino A; Docker, Peter T; Dyer, Charlotte E; Greenway, Gillian M; Greenman, John; Haswell, Stephen J

2011-02-07

Integrated DNA extraction and amplification have been carried out in a microfluidic device using electro-osmotic pumping (EOP) for fluidic control. All the necessary reagents for performing both DNA extraction and polymerase chain reaction (PCR) amplification were pre-loaded into the microfluidic device following encapsulation in agarose gel. Buccal cells were collected using OmniSwabs [Whatman™, UK] and manually added to a chaotropic binding/lysis solution pre-loaded into the microfluidic device. The released DNA was then adsorbed onto a silica monolith contained within the DNA extraction chamber and the microfluidic device sealed using polymer electrodes. The washing and elution steps for DNA extraction were carried out using EOP, resulting in transfer of the eluted DNA into the PCR chamber. Thermal cycling, achieved using a Peltier element, resulted in amplification of the Amelogenin locus as confirmed using conventional capillary gel electrophoresis. It was demonstrated that the PCR reagents could be stored in the microfluidic device for at least 8 weeks at 4 °C with no significant loss of activity. Such methodology lends itself to the production of 'ready-to-use' microfluidic devices containing all the necessary reagents for sample processing, with many obvious applications in forensics and clinical medicine.

Microfluidic Devices in Advanced Caenorhabditis elegans Research.

PubMed

Muthaiyan Shanmugam, Muniesh; Subhra Santra, Tuhin

2016-08-02

The study of model organisms is very important in view of their potential for application to human therapeutic uses. One such model organism is the nematode worm, Caenorhabditis elegans. As a nematode, C. elegans have ~65% similarity with human disease genes and, therefore, studies on C. elegans can be translated to human, as well as, C. elegans can be used in the study of different types of parasitic worms that infect other living organisms. In the past decade, many efforts have been undertaken to establish interdisciplinary research collaborations between biologists, physicists and engineers in order to develop microfluidic devices to study the biology of C. elegans. Microfluidic devices with the power to manipulate and detect bio-samples, regents or biomolecules in micro-scale environments can well fulfill the requirement to handle worms under proper laboratory conditions, thereby significantly increasing research productivity and knowledge. The recent development of different kinds of microfluidic devices with ultra-high throughput platforms has enabled researchers to carry out worm population studies. Microfluidic devices primarily comprises of chambers, channels and valves, wherein worms can be cultured, immobilized, imaged, etc. Microfluidic devices have been adapted to study various worm behaviors, including that deepen our understanding of neuromuscular connectivity and functions. This review will provide a clear account of the vital involvement of microfluidic devices in worm biology.

A "place n play" modular pump for portable microfluidic applications.

PubMed

Li, Gang; Luo, Yahui; Chen, Qiang; Liao, Lingying; Zhao, Jianlong

2012-03-01

This paper presents an easy-to-use, power-free, and modular pump for portable microfluidic applications. The pump module is a degassed particle desorption polydimethylsiloxane (PDMS) slab with an integrated mesh-shaped chamber, which can be attached on the outlet port of microfluidic device to absorb the air in the microfluidic system and then to create a negative pressure for driving fluid. Different from the existing monolithic degassed PDMS pumps that are generally restricted to limited pumping capacity and are only compatible with PDMS-based microfluidic devices, this pump can offer various possible configures of pumping power by varying the geometries of the pump or by combining different pump modules and can also be employed in any material microfluidic devices. The key advantage of this pump is that its operation only requires the user to place the degassed PDMS slab on the outlet ports of microfluidic devices. To help design pumps with a suitable pumping performance, the effect of pump module geometry on its pumping capacity is also investigated. The results indicate that the performance of the degassed PDMS pump is strongly dependent on the surface area of the pump chamber, the exposure area and the volume of the PDMS pump slab. In addition, the initial volume of air in the closed microfluidic system and the cross-linking degree of PDMS also affect the performance of the degassed PDMS pump. Finally, we demonstrated the utility of this modular pumping method by applying it to a glass-based microfluidic device and a PDMS-based protein crystallization microfluidic device.

A “place n play” modular pump for portable microfluidic applications

PubMed Central

Li, Gang; Luo, Yahui; Chen, Qiang; Liao, Lingying; Zhao, Jianlong

2012-01-01

This paper presents an easy-to-use, power-free, and modular pump for portable microfluidic applications. The pump module is a degassed particle desorption polydimethylsiloxane (PDMS) slab with an integrated mesh-shaped chamber, which can be attached on the outlet port of microfluidic device to absorb the air in the microfluidic system and then to create a negative pressure for driving fluid. Different from the existing monolithic degassed PDMS pumps that are generally restricted to limited pumping capacity and are only compatible with PDMS-based microfluidic devices, this pump can offer various possible configures of pumping power by varying the geometries of the pump or by combining different pump modules and can also be employed in any material microfluidic devices. The key advantage of this pump is that its operation only requires the user to place the degassed PDMS slab on the outlet ports of microfluidic devices. To help design pumps with a suitable pumping performance, the effect of pump module geometry on its pumping capacity is also investigated. The results indicate that the performance of the degassed PDMS pump is strongly dependent on the surface area of the pump chamber, the exposure area and the volume of the PDMS pump slab. In addition, the initial volume of air in the closed microfluidic system and the cross-linking degree of PDMS also affect the performance of the degassed PDMS pump. Finally, we demonstrated the utility of this modular pumping method by applying it to a glass-based microfluidic device and a PDMS-based protein crystallization microfluidic device. PMID:22685507

A reconfigurable continuous-flow fluidic routing fabric using a modular, scalable primitive.

PubMed

Silva, Ryan; Bhatia, Swapnil; Densmore, Douglas

2016-07-05

Microfluidic devices, by definition, are required to move liquids from one physical location to another. Given a finite and frequently fixed set of physical channels to route fluids, a primitive design element that allows reconfigurable routing of that fluid from any of n input ports to any n output ports will dramatically change the paradigms by which these chips are designed and applied. Furthermore, if these elements are "regular" regarding their design, the programming and fabrication of these elements becomes scalable. This paper presents such a design element called a transposer. We illustrate the design, fabrication and operation of a single transposer. We then scale this design to create a programmable fabric towards a general-purpose, reconfigurable microfluidic platform analogous to the Field Programmable Gate Array (FPGA) found in digital electronics.

Deviation of a Jet at a T junction at low Reynolds number

NASA Astrophysics Data System (ADS)

Panizza, Pascal; Engl, Wilfried; Ohata, Kouske; Colin, Annie

2006-03-01

We study the hydrodynamic behaviour of a laminar jet flowing through a channel when it reaches a junction. We observe the existence of two possible flow regimes, namely the splitting and deviation of a jet in the most simple microfluidic configuration, namely a T junction. The transition between the two regimes is not monitored by the shape of the T junction nor by capillary effects, but can be easily anticipated in terms of the hydrodynamic properties of the flow. We present a simple hydrodynamic model which is in very good agreement with observed experimental jet behaviour. The transition between both regime acts as a flow or viscosity comparator. We show how this effect can be used for the design of digital and integrated microfluidic devices

A microfluidic platform for precision small-volume sample processing and its use to size separate biological particles with an acoustic microdevice [Precision size separation of biological particles in small-volume samples by an acoustic microfluidic system

DOE PAGES

Fong, Erika J.; Huang, Chao; Hamilton, Julie; ...

2015-11-23

Here, a major advantage of microfluidic devices is the ability to manipulate small sample volumes, thus reducing reagent waste and preserving precious sample. However, to achieve robust sample manipulation it is necessary to address device integration with the macroscale environment. To realize repeatable, sensitive particle separation with microfluidic devices, this protocol presents a complete automated and integrated microfluidic platform that enables precise processing of 0.15–1.5 ml samples using microfluidic devices. Important aspects of this system include modular device layout and robust fixtures resulting in reliable and flexible world to chip connections, and fully-automated fluid handling which accomplishes closed-loop sample collection,more » system cleaning and priming steps to ensure repeatable operation. Different microfluidic devices can be used interchangeably with this architecture. Here we incorporate an acoustofluidic device, detail its characterization, performance optimization, and demonstrate its use for size-separation of biological samples. By using real-time feedback during separation experiments, sample collection is optimized to conserve and concentrate sample. Although requiring the integration of multiple pieces of equipment, advantages of this architecture include the ability to process unknown samples with no additional system optimization, ease of device replacement, and precise, robust sample processing.« less

Digital microfluidic platform for multiplexing enzyme assays: implications for lysosomal storage disease screening in newborns.

PubMed

Sista, Ramakrishna S; Eckhardt, Allen E; Wang, Tong; Graham, Carrie; Rouse, Jeremy L; Norton, Scott M; Srinivasan, Vijay; Pollack, Michael G; Tolun, Adviye A; Bali, Deeksha; Millington, David S; Pamula, Vamsee K

2011-10-01

Newborn screening for lysosomal storage diseases (LSDs) has been gaining considerable interest owing to the availability of enzyme replacement therapies. We present a digital microfluidic platform to perform rapid, multiplexed enzymatic analysis of acid α-glucosidase (GAA) and acid α-galactosidase to screen for Pompe and Fabry disorders. The results were compared with those obtained using standard fluorometric methods. We performed bench-based, fluorometric enzymatic analysis on 60 deidentified newborn dried blood spots (DBSs), plus 10 Pompe-affected and 11 Fabry-affected samples, at Duke Biochemical Genetics Laboratory using a 3-mm punch for each assay and an incubation time of 20 h. We used a digital microfluidic platform to automate fluorometric enzymatic assays at Advanced Liquid Logic Inc. using extract from a single punch for both assays, with an incubation time of 6 h. Assays were also performed with an incubation time of 1 h. Assay results were generally comparable, although mean enzymatic activity for GAA using microfluidics was approximately 3 times higher than that obtained using bench-based methods, which could be attributed to higher substrate concentration. Clear separation was observed between the normal and affected samples at both 6- and 1-h incubation times using digital microfluidics. A digital microfluidic platform compared favorably with a clinical reference laboratory to perform enzymatic analysis in DBSs for Pompe and Fabry disorders. This platform presents a new technology for a newborn screening laboratory to screen LSDs by fully automating all the liquid-handling operations in an inexpensive system, providing rapid results.

3D-printed Microfluidic Devices: Fabrication, Advantages and Limitations—a Mini Review

PubMed Central

Chen, Chengpeng; Mehl, Benjamin T.; Munshi, Akash S.; Townsend, Alexandra D.; Spence, Dana M.; Martin, R. Scott

2016-01-01

A mini-review with 79 references. In this review, the most recent trends in 3D-printed microfluidic devices are discussed. In addition, a focus is given to the fabrication aspects of these devices, with the supplemental information containing detailed instructions for designing a variety of structures including: a microfluidic channel, threads to accommodate commercial fluidic fittings, a flow splitter; a well plate, a mold for PDMS channel casting; and how to combine multiple designs into a single device. The advantages and limitations of 3D-printed microfluidic devices are thoroughly discussed, as are some future directions for the field. PMID:27617038

3D-printed Microfluidic Devices: Fabrication, Advantages and Limitations-a Mini Review.

PubMed

Chen, Chengpeng; Mehl, Benjamin T; Munshi, Akash S; Townsend, Alexandra D; Spence, Dana M; Martin, R Scott

2016-08-21

A mini-review with 79 references. In this review, the most recent trends in 3D-printed microfluidic devices are discussed. In addition, a focus is given to the fabrication aspects of these devices, with the supplemental information containing detailed instructions for designing a variety of structures including: a microfluidic channel, threads to accommodate commercial fluidic fittings, a flow splitter; a well plate, a mold for PDMS channel casting; and how to combine multiple designs into a single device. The advantages and limitations of 3D-printed microfluidic devices are thoroughly discussed, as are some future directions for the field.

A solvent replenishment solution for managing evaporation of biochemical reactions in air-matrix digital microfluidics devices.

PubMed

Jebrail, Mais J; Renzi, Ronald F; Sinha, Anupama; Van De Vreugde, Jim; Gondhalekar, Carmen; Ambriz, Cesar; Meagher, Robert J; Branda, Steven S

2015-01-07

Digital microfluidics (DMF) is a powerful technique for sample preparation and analysis for a broad range of biological and chemical applications. In many cases, it is desirable to carry out DMF on an open surface, such that the matrix surrounding the droplets is ambient air. However, the utility of the air-matrix DMF format has been severely limited by problems with droplet evaporation, especially when the droplet-based biochemical reactions require high temperatures for long periods of time. We present a simple solution for managing evaporation in air-matrix DMF: just-in-time replenishment of the reaction volume using droplets of solvent. We demonstrate that this solution enables DMF-mediated execution of several different biochemical reactions (RNA fragmentation, first-strand cDNA synthesis, and PCR) over a range of temperatures (4-95 °C) and incubation times (up to 1 h or more) without use of oil, humidifying chambers, or off-chip heating modules. Reaction volumes and temperatures were maintained roughly constant over the course of each experiment, such that the reaction kinetics and products generated by the air-matrix DMF device were comparable to those of conventional benchscale reactions. This simple yet effective solution for evaporation management is an important advance in developing air-matrix DMF for a wide variety of new, high-impact applications, particularly in the biomedical sciences.

A solvent replenishment solution for managing evaporation of biochemical reactions in air-matrix digital microfluidics devices

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jebrail, Mais J.; Renzi, Ronald F.; Sinha, Anupama

Digital microfluidics (DMF) is a powerful technique for sample preparation and analysis for a broad range of biological and chemical applications. In many cases, it is desirable to carry out DMF on an open surface, such that the matrix surrounding the droplets is ambient air. However, the utility of the air-matrix DMF format has been severely limited by problems with droplet evaporation, especially when the droplet-based biochemical reactions require high temperatures for long periods of time. We present a simple solution for managing evaporation in air-matrix DMF: just-in-time replenishment of the reaction volume using droplets of solvent. We demonstrate thatmore » this solution enables DMF-mediated execution of several different biochemical reactions (RNA fragmentation, first-strand cDNA synthesis, and PCR) over a range of temperatures (4–95 °C) and incubation times (up to 1 h or more) without use of oil, humidifying chambers, or off-chip heating modules. Reaction volumes and temperatures were maintained roughly constant over the course of each experiment, such that the reaction kinetics and products generated by the air-matrix DMF device were comparable to those of conventional benchscale reactions. As a result, this simple yet effective solution for evaporation management is an important advance in developing air-matrix DMF for a wide variety of new, high-impact applications, particularly in the biomedical sciences.« less

A solvent replenishment solution for managing evaporation of biochemical reactions in air-matrix digital microfluidics devices

DOE PAGES

Jebrail, Mais J.; Renzi, Ronald F.; Sinha, Anupama; ...

2014-10-01

Digital microfluidics (DMF) is a powerful technique for sample preparation and analysis for a broad range of biological and chemical applications. In many cases, it is desirable to carry out DMF on an open surface, such that the matrix surrounding the droplets is ambient air. However, the utility of the air-matrix DMF format has been severely limited by problems with droplet evaporation, especially when the droplet-based biochemical reactions require high temperatures for long periods of time. We present a simple solution for managing evaporation in air-matrix DMF: just-in-time replenishment of the reaction volume using droplets of solvent. We demonstrate thatmore » this solution enables DMF-mediated execution of several different biochemical reactions (RNA fragmentation, first-strand cDNA synthesis, and PCR) over a range of temperatures (4–95 °C) and incubation times (up to 1 h or more) without use of oil, humidifying chambers, or off-chip heating modules. Reaction volumes and temperatures were maintained roughly constant over the course of each experiment, such that the reaction kinetics and products generated by the air-matrix DMF device were comparable to those of conventional benchscale reactions. As a result, this simple yet effective solution for evaporation management is an important advance in developing air-matrix DMF for a wide variety of new, high-impact applications, particularly in the biomedical sciences.« less

Microfluidics-to-Mass Spectrometry: A review of coupling methods and applications

PubMed Central

Wang, Xue; Yi, Lian; Mukhitov, Nikita; Schrell, Adrian M.; Dhumpa, Raghuram; Roper, Michael G.

2014-01-01

Microfluidic devices offer great advantages in integrating sample processes, minimizing sample and reagent volumes, and increasing analysis speed, while mass spectrometry detection provides high information content, is sensitive, and can be used in quantitative analyses. The coupling of microfluidic devices to mass spectrometers is becoming more common with the strengths of both systems being combined to analyze precious and complex samples. This review summarizes select achievements published between 2010 – July 2014 in novel coupling between microfluidic devices and mass spectrometers. The review is subdivided by the types of ionization sources employed, and the different microfluidic systems used. PMID:25458901

Fabrication, Metrology, and Transport Characteristics of Single Polymeric Nanopores in Three-Dimensional Hybrid Microfluidic/Nanofluidic Devices

ERIC Educational Resources Information Center

King, Travis L.

2009-01-01

The incorporation of nanofluidic elements between microfluidic channels to form hybrid microfluidic/nanofluidic architectures allows the extension of microfluidic systems into the third dimension, thus removing the constraints imposed by planarity. Measuring and understanding the behavior of these devices creates new analytical challenges due to…

Pumps for microfluidic cell culture.

PubMed

Byun, Chang Kyu; Abi-Samra, Kameel; Cho, Yoon-Kyoung; Takayama, Shuichi

2014-02-01

In comparison to traditional in vitro cell culture in Petri dishes or well plates, cell culture in microfluidic-based devices enables better control over chemical and physical environments, higher levels of experimental automation, and a reduction in experimental materials. Over the past decade, the advantages associated with cell culturing in microfluidic-based platforms have garnered significant interest and have led to a plethora of studies for high throughput cell assays, organs-on-a-chip applications, temporal signaling studies, and cell sorting. A clear concern for performing cell culture in microfluidic-based devices is deciding on a technique to deliver and pump media to cells that are encased in a microfluidic device. In this review, we summarize recent advances in pumping techniques for microfluidic cell culture and discuss their advantages and possible drawbacks. The ultimate goal of our review is to distill the large body of information available related to pumps for microfluidic cell culture in an effort to assist current and potential users of microfluidic-based devices for advanced in vitro cellular studies. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

In vitro development of donated frozen-thawed human embryos in a prototype static microfluidic device: a randomized controlled trial.

PubMed

Kieslinger, Dorit C; Hao, Zhenxia; Vergouw, Carlijn G; Kostelijk, Elisabeth H; Lambalk, Cornelis B; Le Gac, Séverine

2015-03-01

To compare the development of human embryos in microfluidic devices with culture in standard microdrop dishes, both under static conditions. Prospective randomized controlled trial. In vitro fertilization laboratory. One hundred eighteen donated frozen-thawed human day-4 embryos. Random allocation of embryos that fulfilled the inclusion criteria to single-embryo culture in a microfluidics device (n = 58) or standard microdrop dish (n = 60). Blastocyst formation rate and quality after 24, 28, 48, and 72 hours of culture. The percentage of frozen-thawed day-4 embryos that developed to the blastocyst stage did not differ significantly in the standard microdrop dishes and microfluidic devices after 28 hours of culture (53.3% vs. 58.6%) or at any of the other time points. The proportion of embryos that would have been suitable for embryo transfer was comparable after 28 hours of culture in the control dishes and microfluidic devices (90.0% vs. 93.1%). Furthermore, blastocyst quality was similar in the two study groups. This study shows that a microfluidic device can successfully support human blastocyst development in vitro under static culture conditions. Future studies need to clarify whether earlier stage embryos will benefit from the culture in microfluidic devices more than the tested day-4 embryos because many important steps in the development of human embryos already take place before day 4. Further improvements of the microfluidic device will include parallel culture of single embryos, application of medium refreshment, and built-in sensors. NTR3867. Copyright © 2015 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

Commercialization of microfluidic devices.

PubMed

Volpatti, Lisa R; Yetisen, Ali K

2014-07-01

Microfluidic devices offer automation and high-throughput screening, and operate at low volumes of consumables. Although microfluidics has the potential to reduce turnaround times and costs for analytical devices, particularly in medical, veterinary, and environmental sciences, this enabling technology has had limited diffusion into consumer products. This article analyzes the microfluidics market, identifies issues, and highlights successful commercialization strategies. Addressing niche markets and establishing compatibility with existing workflows will accelerate market penetration. Copyright © 2014 Elsevier Ltd. All rights reserved.

A simple method to produce 2D and 3D microfluidic paper-based analytical devices for clinical analysis.

PubMed

de Oliveira, Ricardo A G; Camargo, Fiamma; Pesquero, Naira C; Faria, Ronaldo Censi

2017-03-08

This paper describes the fabrication of 2D and 3D microfluidic paper-based analytical devices (μPADs) for monitoring glucose, total protein, and nitrite in blood serum and artificial urine. A new method of cutting and sealing filter paper to construct μPADs was demonstrated. Using an inexpensive home cutter printer soft cellulose-based filter paper was easily and precisely cut to produce pattern hydrophilic microchannels. 2D and 3D μPADs were designed with three detection zones each for the colorimetric detection of the analytes. A small volume of samples was added to the μPADs, which was photographed after 15 min using a digital camera. Both μPADs presented an excellent analytical performance for all analytes. The 2D device was applied in artificial urine samples and reached limits of detection (LODs) of 0.54 mM, 5.19 μM, and 2.34 μM for glucose, protein, and nitrite, respectively. The corresponding LODs of the 3D device applied for detecting the same analytes in artificial blood serum were 0.44 mM, 1.26 μM, and 4.35 μM. Copyright © 2017 Elsevier B.V. All rights reserved.

A Student-Made Microfluidic Device for Electrophoretic Separation of Food Dyes

ERIC Educational Resources Information Center

Teerasong, Saowapak; McClain, Robert L.

2011-01-01

We have developed an undergraduate laboratory activity to introduce students to microfluidics. In the activity, each student constructs their own microfluidic device using simple photolithographic techniques and then uses the device to separate a food dye mixture by electrophoresis. Dyes are used so that students are able to visually observe the…

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

PubMed

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

2016-02-21

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

Hybrid Integrated Silicon Microfluidic Platform for Fluorescence Based Biodetection.

PubMed

Chandrasekaran, Arvind; Acharya, Ashwin; You, Jian Liang; Soo, Kim Young; Packirisamy, Muthukumaran; Stiharu, Ion; Darveau, André

2007-09-11

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

Benchtop fabrication of three-dimensional reconfigurable microfluidic devices from paper-polymer composite.

PubMed

Han, Yu Long; Wang, Wenqi; Hu, Jie; Huang, Guoyou; Wang, Shuqi; Lee, Won Gu; Lu, Tian Jian; Xu, Feng

2013-12-21

We presented a benchtop technique that can fabricate reconfigurable, three-dimensional (3D) microfluidic devices made from a soft paper-polymer composite. This fabrication approach can produce microchannels at a minimal width of 100 μm and can be used to prototype 3D microfluidic devices by simple bending and stretching. The entire fabrication process can be finished in 2 hours on a laboratory bench without the need for special equipment involved in lithography. Various functional microfluidic devices (e.g., droplet generator and reconfigurable electronic circuit) were prepared using this paper-polymer hybrid microfluidic system. The developed method can be applied in a wide range of standard applications and emerging technologies such as liquid-phase electronics.

Recent advances in low-cost microfluidic platforms for diagnostic applications.

PubMed

Tomazelli Coltro, Wendell Karlos; Cheng, Chao-Min; Carrilho, Emanuel; de Jesus, Dosil Pereira

2014-08-01

The use of inexpensive materials and cost-effective manufacturing processes for mass production of microfluidic devices is very attractive and has spurred a variety of approaches. Such devices are particularly suited for diagnostic applications in limited resource settings. This review describes the recent and remarkable advances in the use of low-cost substrates for the development of microfluidic devices for diagnostics and clinical assays. Thus, a plethora of new and improved fabrication methods, designs, capabilities, detections, and applications of microfluidic devices fabricated with paper, plastic, and threads are covered. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Finger-triggered portable PDMS suction cup for equipment-free microfluidic pumping

NASA Astrophysics Data System (ADS)

Lee, Sanghyun; Kim, Hojin; Lee, Wonhyung; Kim, Joonwon

2018-12-01

This study presents a finger-triggered portable polydimethylsiloxane suction cup that enables equipment-free microfluidic pumping. The key feature of this method is that its operation only involves a "pressing-and-releasing" action for the cup placed at the outlet of a microfluidic device, which transports the fluid at the inlet toward the outlet through a microchannel. This method is simple, but effective and powerful. The cup is portable and can easily be fabricated from a three-dimensional printed mold, used without any pre-treatment, reversibly bonded to microfluidic devices without leakage, and applied to various material-based microfluidic devices. The effect of the suction cup geometry and fabrication conditions on the pumping performance was investigated. Furthermore, we demonstrated the practical applications of the suction cup by conducting an equipment-free pumping of thermoplastic-based microfluidic devices and water-in-oil droplet generation.

Design and fabrication of chemically robust three-dimensional microfluidic valves.

PubMed

Maltezos, George; Garcia, Erika; Hanrahan, Grady; Gomez, Frank A; Vyawahare, Saurabh; Vyawhare, Saurabh; van Dam, R Michael; Chen, Yan; Scherer, Axel

2007-09-01

A current problem in microfluidics is that poly(dimethylsiloxane) (PDMS), used to fabricate many microfluidic devices, is not compatible with most organic solvents. Fluorinated compounds are more chemically robust than PDMS but, historically, it has been nearly impossible to construct valves out of them by multilayer soft lithography (MSL) due to the difficulty of bonding layers made of "non-stick" fluoropolymers necessary to create traditional microfluidic valves. With our new three-dimensional (3D) valve design we can fabricate microfluidic devices from fluorinated compounds in a single monolithic layer that is resistant to most organic solvents with minimal swelling. This paper describes the design and development of 3D microfluidic valves by molding of a perfluoropolyether, termed Sifel, onto printed wax molds. The fabrication of Sifel-based microfluidic devices using this technique has great potential in chemical synthesis and analysis.

Electrowetting for Digital Microfluidics

NASA Astrophysics Data System (ADS)

Hunt, Tom; Adamson, Kristi; Issadore, David; Westervelt, Robert

2006-03-01

Droplet based chemistry promises to greatly impact biomedical research, providing new avenues for high throughput, low volume assays such as drug screening. Electrowetting on Dielectric (EWOD) is an excellent technique for manipulating microscopic drops of liquid. EWOD uses buried electrodes to locally change the surface energy between a droplet and a substrate. We present microfabricated devices for moving droplets with EWOD. One example of such a device consists of a series of 16 interdigitated electrodes, decreasing in size from 1mm to 20 microns. Each electrode is addressable by an independent, computer controlled, high voltage supply. This work made possible by a gift from Phillip Morris and the NSEC NSF grant PHY-0117795.

Microfluidic method for measuring viscosity using images from smartphone

NASA Astrophysics Data System (ADS)

Kim, Sooyeong; Kim, Kyung Chun; Yeom, Eunseop

2018-05-01

The viscosity of a fluid is the most important characteristic in fluid rheology. Many microfluidic devices have been proposed for easily measuring the fluid viscosity of small samples. A hybrid system consisting of a smartphone and microfluidic device can offer a mobile laboratory for performing a wide range of detection and analysis functions related to healthcare. In this study, a new mobile sensing method based on a microfluidic device was proposed for fluid viscosity measurements. By separately delivering sample and reference fluids into the two inlets of a Y-shaped microfluidic device, an interfacial line is induced at downstream of the device. Because the interfacial width (W) between the sample and reference fluid flows was determined by their pressure ratio, the viscosity (μ) of the sample could be estimated by measuring the interfacial width. To distinguish the interfacial width of a sample, optical images of the flows at downstream of the Y-shaped microfluidic device were acquired using a smartphone. To check the measurement accuracy of the proposed method, the viscosities of glycerol mixtures were compared with those measured by a conventional viscometer. The proposed technique was applied to monitor the variations in blood and oil samples depending on storage or rancidity. We expect that this mobile sensing method based on a microfluidic device could be utilized as a viscometer with significant advantages in terms of mobility, ease-of-operation, and data management.

Automated Long-Term Monitoring of Parallel Microfluidic Operations Applying a Machine Vision-Assisted Positioning Method

PubMed Central

Yip, Hon Ming; Li, John C. S.; Cui, Xin; Gao, Qiannan; Leung, Chi Chiu

2014-01-01

As microfluidics has been applied extensively in many cell and biochemical applications, monitoring the related processes is an important requirement. In this work, we design and fabricate a high-throughput microfluidic device which contains 32 microchambers to perform automated parallel microfluidic operations and monitoring on an automated stage of a microscope. Images are captured at multiple spots on the device during the operations for monitoring samples in microchambers in parallel; yet the device positions may vary at different time points throughout operations as the device moves back and forth on a motorized microscopic stage. Here, we report an image-based positioning strategy to realign the chamber position before every recording of microscopic image. We fabricate alignment marks at defined locations next to the chambers in the microfluidic device as reference positions. We also develop image processing algorithms to recognize the chamber positions in real-time, followed by realigning the chambers to their preset positions in the captured images. We perform experiments to validate and characterize the device functionality and the automated realignment operation. Together, this microfluidic realignment strategy can be a platform technology to achieve precise positioning of multiple chambers for general microfluidic applications requiring long-term parallel monitoring of cell and biochemical activities. PMID:25133248

Review of microfluidic cell culture devices for the control of gaseous microenvironments in vitro

NASA Astrophysics Data System (ADS)

Wu, H.-M.; Lee, T.-A.; Ko, P.-L.; Chiang, H.-J.; Peng, C.-C.; Tung, Y.-C.

2018-04-01

Gaseous microenvironments play important roles in various biological activities in vivo. However, it is challenging to precisely control gaseous microenvironments in vitro for cell culture due to the high diffusivity nature of gases. In recent years, microfluidics has paved the way for the development of new types of cell culture devices capable of manipulating cellular microenvironments, and provides a powerful tool for in vitro cell studies. This paper reviews recent developments of microfluidic cell culture devices for the control of gaseous microenvironments, and discusses the advantages and limitations of current devices. We conclude with suggestions for the future development of microfluidic cell culture devices for the control of gaseous microenvironments.

Efficient generation of hepatic cells from mesenchymal stromal cells by an innovative bio-microfluidic cell culture device.

PubMed

Yen, Meng-Hua; Wu, Yuan-Yi; Liu, Yi-Shiuan; Rimando, Marilyn; Ho, Jennifer Hui-Chun; Lee, Oscar Kuang-Sheng

2016-08-19

Mesenchymal stromal cells (MSCs) are multipotent and have great potential in cell therapy. Previously we reported the differentiation potential of human MSCs into hepatocytes in vitro and that these cells can rescue fulminant hepatic failure. However, the conventional static culture method neither maintains growth factors at an optimal level constantly nor removes cellular waste efficiently. In addition, not only is the duration of differentiating hepatocyte lineage cells from MSCs required to improve, but also the need for a large number of hepatocytes for cell therapy has not to date been addressed fully. The purpose of this study is to design and develop an innovative microfluidic device to overcome these shortcomings. We designed and fabricated a microfluidic device and a culture system for hepatic differentiation of MSCs using our protocol reported previously. The microfluidic device contains a large culture chamber with a stable uniform flow to allow homogeneous distribution and expansion as well as efficient induction of hepatic differentiation for MSCs. The device enables real-time observation under light microscopy and exhibits a better differentiation efficiency for MSCs compared with conventional static culture. MSCs grown in the microfluidic device showed a higher level of hepatocyte marker gene expression under hepatic induction. Functional analysis of hepatic differentiation demonstrated significantly higher urea production in the microfluidic device after 21 days of hepatic differentiation. The microfluidic device allows the generation of a large number of MSCs and induces hepatic differentiation of MSCs efficiently. The device can be adapted for scale-up production of hepatic cells from MSCs for cellular therapy.

Rapid mask prototyping for microfluidics.

PubMed

Maisonneuve, B G C; Honegger, T; Cordeiro, J; Lecarme, O; Thiry, T; Fuard, D; Berton, K; Picard, E; Zelsmann, M; Peyrade, D

2016-03-01

With the rise of microfluidics for the past decade, there has come an ever more pressing need for a low-cost and rapid prototyping technology, especially for research and education purposes. In this article, we report a rapid prototyping process of chromed masks for various microfluidic applications. The process takes place out of a clean room, uses a commercially available video-projector, and can be completed in less than half an hour. We quantify the ranges of fields of view and of resolutions accessible through this video-projection system and report the fabrication of critical microfluidic components (junctions, straight channels, and curved channels). To exemplify the process, three common devices are produced using this method: a droplet generation device, a gradient generation device, and a neuro-engineering oriented device. The neuro-engineering oriented device is a compartmentalized microfluidic chip, and therefore, required the production and the precise alignment of two different masks.

Rapid mask prototyping for microfluidics

PubMed Central

Maisonneuve, B. G. C.; Honegger, T.; Cordeiro, J.; Lecarme, O.; Thiry, T.; Fuard, D.; Berton, K.; Picard, E.; Zelsmann, M.; Peyrade, D.

2016-01-01

With the rise of microfluidics for the past decade, there has come an ever more pressing need for a low-cost and rapid prototyping technology, especially for research and education purposes. In this article, we report a rapid prototyping process of chromed masks for various microfluidic applications. The process takes place out of a clean room, uses a commercially available video-projector, and can be completed in less than half an hour. We quantify the ranges of fields of view and of resolutions accessible through this video-projection system and report the fabrication of critical microfluidic components (junctions, straight channels, and curved channels). To exemplify the process, three common devices are produced using this method: a droplet generation device, a gradient generation device, and a neuro-engineering oriented device. The neuro-engineering oriented device is a compartmentalized microfluidic chip, and therefore, required the production and the precise alignment of two different masks. PMID:27014396

Exploration of microfluidic devices based on multi-filament threads and textiles: A review

PubMed Central

Nilghaz, A.; Ballerini, D. R.; Shen, W.

2013-01-01

In this paper, we review the recent progress in the development of low-cost microfluidic devices based on multifilament threads and textiles for semi-quantitative diagnostic and environmental assays. Hydrophilic multifilament threads are capable of transporting aqueous and non-aqueous fluids via capillary action and possess desirable properties for building fluid transport pathways in microfluidic devices. Thread can be sewn onto various support materials to form fluid transport channels without the need for the patterned hydrophobic barriers essential for paper-based microfluidic devices. Thread can also be used to manufacture fabrics which can be patterned to achieve suitable hydrophilic-hydrophobic contrast, creating hydrophilic channels which allow the control of fluids flow. Furthermore, well established textile patterning methods and combination of hydrophilic and hydrophobic threads can be applied to fabricate low-cost microfluidic devices that meet the low-cost and low-volume requirements. In this paper, we review the current limitations and shortcomings of multifilament thread and textile-based microfluidics, and the research efforts to date on the development of fluid flow control concepts and fabrication methods. We also present a summary of different methods for modelling the fluid capillary flow in microfluidic thread and textile-based systems. Finally, we summarized the published works of thread surface treatment methods and the potential of combining multifilament thread with other materials to construct devices with greater functionality. We believe these will be important research focuses of thread- and textile-based microfluidics in future. PMID:24086179

Advances in Testing Techniques for Digital Microfluidic Biochips

PubMed Central

Shukla, Vineeta; Hussin, Fawnizu Azmadi; Hamid, Nor Hisham; Zain Ali, Noohul Basheer

2017-01-01

With the advancement of digital microfluidics technology, applications such as on-chip DNA analysis, point of care diagnosis and automated drug discovery are common nowadays. The use of Digital Microfluidics Biochips (DMFBs) in disease assessment and recognition of target molecules had become popular during the past few years. The reliability of these DMFBs is crucial when they are used in various medical applications. Errors found in these biochips are mainly due to the defects developed during droplet manipulation, chip degradation and inaccuracies in the bio-assay experiments. The recently proposed Micro-electrode-dot Array (MEDA)-based DMFBs involve both fluidic and electronic domains in the micro-electrode cell. Thus, the testing techniques for these biochips should be revised in order to ensure proper functionality. This paper describes recent advances in the testing technologies for digital microfluidics biochips, which would serve as a useful platform for developing revised/new testing techniques for MEDA-based biochips. Therefore, the relevancy of these techniques with respect to testing of MEDA-based biochips is analyzed in order to exploit the full potential of these biochips. PMID:28749411

Advances in Testing Techniques for Digital Microfluidic Biochips.

PubMed

Shukla, Vineeta; Hussin, Fawnizu Azmadi; Hamid, Nor Hisham; Zain Ali, Noohul Basheer

2017-07-27

With the advancement of digital microfluidics technology, applications such as on-chip DNA analysis, point of care diagnosis and automated drug discovery are common nowadays. The use of Digital Microfluidics Biochips (DMFBs) in disease assessment and recognition of target molecules had become popular during the past few years. The reliability of these DMFBs is crucial when they are used in various medical applications. Errors found in these biochips are mainly due to the defects developed during droplet manipulation, chip degradation and inaccuracies in the bio-assay experiments. The recently proposed Micro-electrode-dot Array (MEDA)-based DMFBs involve both fluidic and electronic domains in the micro-electrode cell. Thus, the testing techniques for these biochips should be revised in order to ensure proper functionality. This paper describes recent advances in the testing technologies for digital microfluidics biochips, which would serve as a useful platform for developing revised/new testing techniques for MEDA-based biochips. Therefore, the relevancy of these techniques with respect to testing of MEDA-based biochips is analyzed in order to exploit the full potential of these biochips.

Soft tubular microfluidics for 2D and 3D applications

PubMed Central

Xi, Wang; Kong, Fang; Yeo, Joo Chuan; Yu, Longteng; Sonam, Surabhi; Dao, Ming; Gong, Xiaobo; Lim, Chwee Teck

2017-01-01

Microfluidics has been the key component for many applications, including biomedical devices, chemical processors, microactuators, and even wearable devices. This technology relies on soft lithography fabrication which requires cleanroom facilities. Although popular, this method is expensive and labor-intensive. Furthermore, current conventional microfluidic chips precludes reconfiguration, making reiterations in design very time-consuming and costly. To address these intrinsic drawbacks of microfabrication, we present an alternative solution for the rapid prototyping of microfluidic elements such as microtubes, valves, and pumps. In addition, we demonstrate how microtubes with channels of various lengths and cross-sections can be attached modularly into 2D and 3D microfluidic systems for functional applications. We introduce a facile method of fabricating elastomeric microtubes as the basic building blocks for microfluidic devices. These microtubes are transparent, biocompatible, highly deformable, and customizable to various sizes and cross-sectional geometries. By configuring the microtubes into deterministic geometry, we enable rapid, low-cost formation of microfluidic assemblies without compromising their precision and functionality. We demonstrate configurable 2D and 3D microfluidic systems for applications in different domains. These include microparticle sorting, microdroplet generation, biocatalytic micromotor, triboelectric sensor, and even wearable sensing. Our approach, termed soft tubular microfluidics, provides a simple, cheaper, and faster solution for users lacking proficiency and access to cleanroom facilities to design and rapidly construct microfluidic devices for their various applications and needs. PMID:28923968

Soft tubular microfluidics for 2D and 3D applications

NASA Astrophysics Data System (ADS)

Xi, Wang; Kong, Fang; Yeo, Joo Chuan; Yu, Longteng; Sonam, Surabhi; Dao, Ming; Gong, Xiaobo; Teck Lim, Chwee

2017-10-01

Microfluidics has been the key component for many applications, including biomedical devices, chemical processors, microactuators, and even wearable devices. This technology relies on soft lithography fabrication which requires cleanroom facilities. Although popular, this method is expensive and labor-intensive. Furthermore, current conventional microfluidic chips precludes reconfiguration, making reiterations in design very time-consuming and costly. To address these intrinsic drawbacks of microfabrication, we present an alternative solution for the rapid prototyping of microfluidic elements such as microtubes, valves, and pumps. In addition, we demonstrate how microtubes with channels of various lengths and cross-sections can be attached modularly into 2D and 3D microfluidic systems for functional applications. We introduce a facile method of fabricating elastomeric microtubes as the basic building blocks for microfluidic devices. These microtubes are transparent, biocompatible, highly deformable, and customizable to various sizes and cross-sectional geometries. By configuring the microtubes into deterministic geometry, we enable rapid, low-cost formation of microfluidic assemblies without compromising their precision and functionality. We demonstrate configurable 2D and 3D microfluidic systems for applications in different domains. These include microparticle sorting, microdroplet generation, biocatalytic micromotor, triboelectric sensor, and even wearable sensing. Our approach, termed soft tubular microfluidics, provides a simple, cheaper, and faster solution for users lacking proficiency and access to cleanroom facilities to design and rapidly construct microfluidic devices for their various applications and needs.

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

ERIC Educational Resources Information Center

Wang, Bo; Lin, Zhiqiang; Wang, Min

2015-01-01

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

Waste-to-energy conversion from a microfluidic device

NASA Astrophysics Data System (ADS)

López-González, B.; Jiménez-Valdés, R. J.; Moreno-Zuria, A.; Cuevas-Muñiz, F. M.; Ledesma-García, J.; García-Cordero, J. L.; Arriaga, L. G.

2017-08-01

This work reports the successful harvesting of energy from waste produced in a microfluidic device using a fuel cell. A miniaturized glucose air-breathing microfluidic fuel cell (ABμFFC) was designed, fabricated and tested with three different configurations according to their electrode nature: inorganic, hybrid and biofuel cell. Each ABμFFC was characterized using an ideal medium, with sterile cell culture medium, and with waste produced on a microfluidic device. The inorganic-ABμFFC exhibited the highest performance compared to the rest of the configurations. As a proof-of-concept, cancer cells were cultured on a microfluidic device and the consumed cell culture media (glucose concentration <11 mM) was used as an energy source without further treatment, into the inorganic-ABμFFC. The fuel cell generated a maximum total power of 5.2 μW, which is enough energy to power low-consumption microelectronic chips. This application demonstrates that the waste produced by microfluidic applications could be potentially scavenged to produce electrical energy. It also opens the possibility to develop truly energy self-sufficient portable devices.

Development of a Mechatronic Syringe Pump to Control Fluid Flow in a Microfluidic Device Based on Polyimide Film

NASA Astrophysics Data System (ADS)

Sek Tee, Kian; Sharil Saripan, Muhammad; Yap, Hiung Yin; Fhong Soon, Chin

2017-08-01

With the advancement in microfluidic technology, fluid flow control for syringe pump is always essential. In this paper, a mechatronic syringe pump will be developed and customized to control the fluid flow in a poly-dimethylsiloxane (PDMS) microfluidic device based on a polyimide laminating film. The syringe pump is designed to drive fluid with flow rates of 100 and 1000 μl/min which intended to drive continuous fluid in a polyimide based microfluidic device. The electronic system consists of an Arduino microcontroller board and a uni-polar stepper motor. In the system, the uni-polar stepper motor was coupled to a linear slider attached to the plunger of a syringe pump. As the motor rotates, the plunger pumps the liquid out of the syringe. The accuracy of the fluid flow rate was determined by adjusting the number of micro-step/revolution to drive the stepper motor to infuse fluid into the microfluidic device. With the precise control of the electronic system, the syringe pump could accurately inject fluid volume at 100 and 1000 μl/min into a microfluidic device.

Developing a protocol for creating microfluidic devices with a 3D printer, PDMS, and glass

NASA Astrophysics Data System (ADS)

Collette, Robyn; Novak, Eric; Shirk, Kathryn

2015-03-01

Microfluidics research requires the design and fabrication of devices that have the ability to manipulate small volumes of fluid, typically ranging from microliters to picoliters. These devices are used for a wide range of applications including the assembly of materials and testing of biological samples. Many methods have been previously developed to create microfluidic devices, including traditional nanolithography techniques. However, these traditional techniques are cost-prohibitive for many small-scale laboratories. This research explores a relatively low-cost technique using a 3D printed master, which is used as a template for the fabrication of polydimethylsiloxane (PDMS) microfluidic devices. The masters are designed using computer aided design (CAD) software and can be printed and modified relatively quickly. We have developed a protocol for creating simple microfluidic devices using a 3D printer and PDMS adhered to glass. This relatively simple and lower-cost technique can now be scaled to more complicated device designs and applications. Funding provided by the Undergraduate Research Grant Program at Shippensburg University and the Student/Faculty Research Engagement Grants from the College of Arts and Sciences at Shippensburg University.

Theoretical design and analysis of multivolume digital assays with wide dynamic range validated experimentally with microfluidic digital PCR.

PubMed

Kreutz, Jason E; Munson, Todd; Huynh, Toan; Shen, Feng; Du, Wenbin; Ismagilov, Rustem F

2011-11-01

This paper presents a protocol using theoretical methods and free software to design and analyze multivolume digital PCR (MV digital PCR) devices; the theory and software are also applicable to design and analysis of dilution series in digital PCR. MV digital PCR minimizes the total number of wells required for "digital" (single molecule) measurements while maintaining high dynamic range and high resolution. In some examples, multivolume designs with fewer than 200 total wells are predicted to provide dynamic range with 5-fold resolution similar to that of single-volume designs requiring 12,000 wells. Mathematical techniques were utilized and expanded to maximize the information obtained from each experiment and to quantify performance of devices and were experimentally validated using the SlipChip platform. MV digital PCR was demonstrated to perform reliably, and results from wells of different volumes agreed with one another. No artifacts due to different surface-to-volume ratios were observed, and single molecule amplification in volumes ranging from 1 to 125 nL was self-consistent. The device presented here was designed to meet the testing requirements for measuring clinically relevant levels of HIV viral load at the point-of-care (in plasma, <500 molecules/mL to >1,000,000 molecules/mL), and the predicted resolution and dynamic range was experimentally validated using a control sequence of DNA. This approach simplifies digital PCR experiments, saves space, and thus enables multiplexing using separate areas for each sample on one chip, and facilitates the development of new high-performance diagnostic tools for resource-limited applications. The theory and software presented here are general and are applicable to designing and analyzing other digital analytical platforms including digital immunoassays and digital bacterial analysis. It is not limited to SlipChip and could also be useful for the design of systems on platforms including valve-based and droplet-based platforms. In a separate publication by Shen et al. (J. Am. Chem. Soc., 2011, DOI: 10.1021/ja2060116), this approach is used to design and test digital RT-PCR devices for quantifying RNA.

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

NASA Astrophysics Data System (ADS)

Alvankarian, Jafar; Yeop Majlis, Burhanuddin

2012-03-01

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

On-demand acoustic droplet splitting and steering in a disposable microfluidic chip.

PubMed

Park, Jinsoo; Jung, Jin Ho; Park, Kwangseok; Destgeer, Ghulam; Ahmed, Husnain; Ahmad, Raheel; Sung, Hyung Jin

2018-01-30

On-chip droplet splitting is one of the fundamental droplet-based microfluidic unit operations to control droplet volume after production and increase operational capability, flexibility, and throughput. Various droplet splitting methods have been proposed, and among them the acoustic droplet splitting method is promising because of its label-free operation without any physical or thermal damage to droplets. Previous acoustic droplet splitting methods faced several limitations: first, they employed a cross-type acoustofluidic device that precluded multichannel droplet splitting; second, they required irreversible bonding between a piezoelectric substrate and a microfluidic chip, such that the fluidic chip was not replaceable. Here, we present a parallel-type acoustofluidic device with a disposable microfluidic chip to address the limitations of previous acoustic droplet splitting devices. In the proposed device, an acoustic field is applied in the direction opposite to the flow direction to achieve multichannel droplet splitting and steering. A disposable polydimethylsiloxane microfluidic chip is employed in the developed device, thereby removing the need for permanent bonding and improving the flexibility of the droplet microfluidic device. We experimentally demonstrated on-demand acoustic droplet bi-splitting and steering with precise control over the droplet splitting ratio, and we investigated the underlying physical mechanisms of droplet splitting and steering based on Laplace pressure and ray acoustics analyses, respectively. We also demonstrated droplet tri-splitting to prove the feasibility of multichannel droplet splitting. The proposed on-demand acoustic droplet splitting device enables on-chip droplet volume control in various droplet-based microfluidic applications.

Replaceable Microfluidic Cartridges for a PCR Biosensor

NASA Technical Reports Server (NTRS)

Francis, Kevin; Sullivan, Ron

2005-01-01

The figure depicts a replaceable microfluidic cartridge that is a component of a miniature biosensor that detects target deoxyribonucleic acid (DNA) sequences. The biosensor utilizes (1) polymerase chain reactions (PCRs) to multiply the amount of DNA to be detected, (2) fluorogenic polynucleotide probe chemicals for labeling the target DNA sequences, and (3) a high-sensitivity epifluorescence-detection optoelectronic subsystem. Microfluidics is a relatively new field of device development in which one applies techniques for fabricating microelectromechanical systems (MEMS) to miniature systems for containing and/or moving fluids. Typically, microfluidic devices are microfabricated, variously, from silicon or polymers. The development of microfluidic devices for applications that involve PCR and fluorescence-based detection of PCR products poses special challenges

Monolithic microfluidic concentrators and mixers

DOEpatents

Frechet, Jean M.; Svec, Frantisek; Yu, Cong; Rohr, Thomas

2005-05-03

Microfluidic devices comprising porous monolithic polymer for concentration, extraction or mixing of fluids. A method for in situ preparation of monolithic polymers by in situ initiated polymerization of polymer precursors within microchannels of a microfluidic device and their use for solid phase extraction (SPE), preconcentration, concentration and mixing.

Sperm quality assessment via separation and sedimentation in a microfluidic device.

PubMed

Chen, Chang-Yu; Chiang, Tsun-Chao; Lin, Cheng-Ming; Lin, Shu-Sheng; Jong, De-Shien; Tsai, Vincent F-S; Hsieh, Ju-Ton; Wo, Andrew M

2013-09-07

A major reason for infertility is due to male factors, including the quality of spermatozoa, which is a primary factor and often difficult to assess, particularly the total sperm concentration and its motile percentage. This work presents a simple microfluidic device to assess sperm quality by quantifying both total and motile sperm counts. The key design feature of the microfluidic device is two channels separated by a permeative phase-guide structure, where one channel is filled with raw semen and the other with pure buffer. The semen sample was allowed to reach equilibrium in both chambers, whereas non-motile sperms remained in the original channel, and roughly half of the motile sperms would swim across the phase-guide barrier into the buffer channel. Sperms in each channel agglomerated into pellets after centrifugation, with the corresponding area representing total and motile sperm concentrations. Total sperm concentration up to 10(8) sperms per ml and motile percentage in the range of 10-70% were tested, encompassing the cutoff value of 40% stated by World Health Organization standards. Results from patient samples show compact and robust pellets after centrifugation. Comparison of total sperm concentration between the microfluidic device and the Makler chamber reveal they agree within 5% and show strong correlation, with a coefficient of determination of R(2) = 0.97. Motile sperm count between the microfluidic device and the Makler chamber agrees within 5%, with a coefficient of determination of R(2) = 0.84. Comparison of results from the Makler Chamber, sperm quality analyzer, and the microfluidic device revealed that results from the microfluidic device agree well with the Makler chamber. The sperm microfluidic chip analyzes both total and motile sperm concentrations in one spin, is accurate and easy to use, and should enable sperm quality analysis with ease.

Hydrogen peroxide concentration by pervaporation of a ternary liquid solution in microfluidics.

PubMed

Ziemecka, Iwona; Haut, Benoît; Scheid, Benoit

2015-01-21

Pervaporation in a microfluidic device is performed on liquid ternary solutions of hydrogen peroxide-water-methanol in order to concentrate hydrogen peroxide (H2O2) by removing methanol. The quantitative analysis of the pervaporation of solutions with different initial compositions is performed, varying the operating temperature of the microfluidic device. Experimental results together with a mathematical model of the separation process are used to understand the effect of the operating conditions on the microfluidic device efficiency. The parameters influencing significantly the performance of pervaporation in the microfluidic device are determined and the limitations of the process are discussed. For the analysed system, the operating temperature of the chip has to be below the temperature at which H2O2 decomposes. Therefore, the choice of an adequate reduced operating pressure is required, depending on the expected separation efficiency.

Rapid and low-cost hot-embossing of polycaprolactone microfluidic devices

NASA Astrophysics Data System (ADS)

Fan, Yiqiang; Liu, Shicheng; He, Jianyun; Gao, Kexin; Zhang, Yajun

2018-01-01

Polycaprolactone (PCL) is a low-cost biocompatible and biodegradable material which is highly suitable for the short-live applications like microfluidics in the biological and medical field. In this study, a rapid and low-cost microfabrication technique for PCL-based microfluidic devices is proposed, the SU-8 mold fabricated on the silicon substrate was used for the hot-embossing of microstructures on PCL. Since PCL after the molding process is optically non-transparent, to improve the visibility of the fluid in the microfluidic device and enclosing the microchannel, a transparency adhesive film which originally used for the sealing of PCR well-plate is used for the sealing of the microchannels embossed on PCL substrate. The profile of the fabricated microchannels was carefully characterized, the bonding strength is tested and several PCL-based microfluidic devices were also fabricated and tested for demonstration.

Fabrication and Evaluation of Microfluidic Immunoassay Devices with Antibody-Immobilized Microbeads Retained in Porous Hydrogel Micropillars.

PubMed

Kasama, Toshihiro; Kaji, Noritada; Tokeshi, Manabu; Baba, Yoshinobu

2017-01-01

Due to the inherent characteristics including confinement of molecular diffusion and high surface-to-volume ratio, microfluidic device-based immunoassay has great advantages in cost, speed, sensitivity, and so on, compared with conventional techniques such as microtiter plate-based ELISA, latex agglutination method, and lateral flow immunochromatography. In this paper, we explain the detection of C-reactive protein as a model antigen by using our microfluidic immunoassay device, so-called immuno-pillar device. We describe in detail how we fabricated and used the immuno-pillar devices.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fong, Erika J.; Huang, Chao; Hamilton, Julie

Here, a major advantage of microfluidic devices is the ability to manipulate small sample volumes, thus reducing reagent waste and preserving precious sample. However, to achieve robust sample manipulation it is necessary to address device integration with the macroscale environment. To realize repeatable, sensitive particle separation with microfluidic devices, this protocol presents a complete automated and integrated microfluidic platform that enables precise processing of 0.15–1.5 ml samples using microfluidic devices. Important aspects of this system include modular device layout and robust fixtures resulting in reliable and flexible world to chip connections, and fully-automated fluid handling which accomplishes closed-loop sample collection,more » system cleaning and priming steps to ensure repeatable operation. Different microfluidic devices can be used interchangeably with this architecture. Here we incorporate an acoustofluidic device, detail its characterization, performance optimization, and demonstrate its use for size-separation of biological samples. By using real-time feedback during separation experiments, sample collection is optimized to conserve and concentrate sample. Although requiring the integration of multiple pieces of equipment, advantages of this architecture include the ability to process unknown samples with no additional system optimization, ease of device replacement, and precise, robust sample processing.« less

Ice matrix in reconfigurable microfluidic systems

NASA Astrophysics Data System (ADS)

Bossi, A. M.; Vareijka, M.; Piletska, E. V.; Turner, A. P. F.; Meglinski, I.; Piletsky, S. A.

2013-07-01

Microfluidic devices find many applications in biotechnologies. Here, we introduce a flexible and biocompatible microfluidic ice-based platform with tunable parameters and configuration of microfluidic patterns that can be changed multiple times during experiments. Freezing and melting of cavities, channels and complex relief structures created and maintained in the bulk of ice by continuous scanning of an infrared laser beam are used as a valve action in microfluidic systems. We demonstrate that pre-concentration of samples and transport of ions and dyes through the open channels created can be achieved in ice microfluidic patterns by IR laser-assisted zone melting. The proposed approach can be useful for performing separation and sensing processes in flexible reconfigurable microfluidic devices.

Encapsulation of cell into monodispersed hydrogels on microfluidic device

NASA Astrophysics Data System (ADS)

Choi, Chang-Hyoung; Lee, Ji-Hye; Shim, Hyun-Woo; Lee, Nae-Rym; Jung, Jae-Hoon; Yoon, Tae-Ho; Kim, Dong-Pyo; Lee, Chang-Soo

2007-12-01

In here, we present the microfluidic approach to produce monodispersed microbeads that will contain viable cells. The utilization of microfludics is helpful to synthesize monodispersed alginate hydrogels and in situ encapsulate cell into the generating hydrogels in microfludic device. First, the condition of formation of hydrogels in multiphase flows including oil, CaCl II, and alginate was optimized. Based on the preliminary survey, microfludic device could easily manipulate the size of alginate beads having narrow size distribution. The microfluidic method manipulates the size of hydrogel microbeads from 30 to 200um with a variation less than 2%. For the proof of concept of cell entrapment, the live yeast expressing green fluorescence protein is successfully encapsulated in microfluidic device.

Recent microfluidic devices for studying gamete and embryo biomechanics.

PubMed

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

2015-06-25

The technical challenges of biomechanic research such as single cell analysis at a high monetary cost, labor, and time for just a small number of measurements is a good match to the strengths of microfluidic devices. New scientific discoveries in the fertilization and embryo development process, of which biomechanics is a major subset of interest, is crucial to fuel the continual improvement of clinical practice in assisted reproduction. The following review will highlight some recent microfluidic devices tailored for gamete and embryo biomechanics where biomimicry arises as a major theme of microfluidic device design and function, and the application of fundamental biomechanic principles are used to improve outcomes of cryopreservation. Copyright © 2015 Elsevier Ltd. All rights reserved.

A practical guide for the fabrication of microfluidic devices using glass and silicon

PubMed Central

Iliescu, Ciprian; Taylor, Hayden; Avram, Marioara; Miao, Jianmin; Franssila, Sami

2012-01-01

This paper describes the main protocols that are used for fabricating microfluidic devices from glass and silicon. Methods for micropatterning glass and silicon are surveyed, and their limitations are discussed. Bonding methods that can be used for joining these materials are summarized and key process parameters are indicated. The paper also outlines techniques for forming electrical connections between microfluidic devices and external circuits. A framework is proposed for the synthesis of a complete glass/silicon device fabrication flow. PMID:22662101

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

PubMed

Miura, Takashi; Yokokawa, Ryuji

2016-08-01

Organ culture systems are used to elucidate the mechanisms of pattern formation in developmental biology. Various organ culture techniques have been used, but the lack of microcirculation in such cultures impedes the long-term maintenance of larger tissues. Recent advances in microfluidic devices now enable us to utilize self-organized perfusable capillary networks in organ cultures. In this review, we will overview past approaches to organ culture and current technical advances in microfluidic devices, and discuss possible applications of microfluidics towards the study of developmental biology. © 2016 Japanese Society of Developmental Biologists.

Multi-step Variable Height Photolithography for Valved Multilayer Microfluidic Devices.

PubMed

Brower, Kara; White, Adam K; Fordyce, Polly M

2017-01-27

Microfluidic systems have enabled powerful new approaches to high-throughput biochemical and biological analysis. However, there remains a barrier to entry for non-specialists who would benefit greatly from the ability to develop their own microfluidic devices to address research questions. Particularly lacking has been the open dissemination of protocols related to photolithography, a key step in the development of a replica mold for the manufacture of polydimethylsiloxane (PDMS) devices. While the fabrication of single height silicon masters has been explored extensively in literature, fabrication steps for more complicated photolithography features necessary for many interesting device functionalities (such as feature rounding to make valve structures, multi-height single-mold patterning, or high aspect ratio definition) are often not explicitly outlined. Here, we provide a complete protocol for making multilayer microfluidic devices with valves and complex multi-height geometries, tunable for any application. These fabrication procedures are presented in the context of a microfluidic hydrogel bead synthesizer and demonstrate the production of droplets containing polyethylene glycol (PEG diacrylate) and a photoinitiator that can be polymerized into solid beads. This protocol and accompanying discussion provide a foundation of design principles and fabrication methods that enables development of a wide variety of microfluidic devices. The details included here should allow non-specialists to design and fabricate novel devices, thereby bringing a host of recently developed technologies to their most exciting applications in biological laboratories.

Detachably assembled microfluidic device for perfusion culture and post-culture analysis of a spheroid array.

PubMed

Sakai, Yusuke; Hattori, Koji; Yanagawa, Fumiki; Sugiura, Shinji; Kanamori, Toshiyuki; Nakazawa, Kohji

2014-07-01

Microfluidic devices permit perfusion culture of three-dimensional (3D) tissue, mimicking the flow of blood in vascularized 3D tissue in our body. Here, we report a microfluidic device composed of a two-part microfluidic chamber chip and multi-microwell array chip able to be disassembled at the culture endpoint. Within the microfluidic chamber, an array of 3D tissue aggregates (spheroids) can be formed and cultured under perfusion. Subsequently, detailed post-culture analysis of the spheroids collected from the disassembled device can be performed. This device facilitates uniform spheroid formation, growth analysis in a high-throughput format, controlled proliferation via perfusion flow rate, and post-culture analysis of spheroids. We used the device to culture spheroids of human hepatocellular carcinoma (HepG2) cells under two controlled perfusion flow rates. HepG2 spheroids exhibited greater cell growth at higher perfusion flow rates than at lower perfusion flow rates, and exhibited different metabolic activity and mRNA and protein expression under the different flow rate conditions. These results show the potential of perfusion culture to precisely control the culture environment in microfluidic devices. The construction of spheroid array chambers allows multiple culture conditions to be tested simultaneously, with potential applications in toxicity and drug screening. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Control and automation of multilayered integrated microfluidic device fabrication.

PubMed

Kipper, Sarit; Frolov, Ludmila; Guy, Ortal; Pellach, Michal; Glick, Yair; Malichi, Asaf; Knisbacher, Binyamin A; Barbiro-Michaely, Efrat; Avrahami, Dorit; Yavets-Chen, Yehuda; Levanon, Erez Y; Gerber, Doron

2017-01-31

Integrated microfluidics is a sophisticated three-dimensional (multi layer) solution for high complexity serial or parallel processes. Fabrication of integrated microfluidic devices requires soft lithography and the stacking of thin-patterned PDMS layers. Precise layer alignment and bonding is crucial. There are no previously reported standards for alignment of the layers, which is mostly performed using uncontrolled processes with very low alignment success. As a result, integrated microfluidics is mostly used in academia rather than in the many potential industrial applications. We have designed and manufactured a semiautomatic Microfluidic Device Assembly System (μDAS) for full device production. μDAS comprises an electrooptic mechanical system consisting of four main parts: optical system, smart media holder (for PDMS), a micropositioning xyzθ system and a macropositioning XY mechanism. The use of the μDAS yielded valuable information regarding PDMS as the material for device fabrication, revealed previously unidentified errors, and enabled optimization of a robust fabrication process. In addition, we have demonstrated the utilization of the μDAS technology for fabrication of a complex 3 layered device with over 12 000 micromechanical valves and an array of 64 × 64 DNA spots on a glass substrate with high yield and high accuracy. We increased fabrication yield from 25% to about 85% with an average layer alignment error of just ∼4 μm. It also increased our protein expression yields from 80% to over 90%, allowing us to investigate more proteins per experiment. The μDAS has great potential to become a valuable tool for both advancing integrated microfluidics in academia and producing and applying microfluidic devices in the industry.

Progress in the development and integration of fluid flow control tools in paper microfluidics.

PubMed

Fu, Elain; Downs, Corey

2017-02-14

Paper microfluidics is a rapidly growing subfield of microfluidics in which paper-like porous materials are used to create analytical devices. There is a need for higher performance field-use tests for many application domains including human disease diagnosis, environmental monitoring, and veterinary medicine. A key factor in creating high performance paper-based devices is the ability to manipulate fluid flow within the devices. This critical review is focused on the progress that has been made in (i) the development of fluid flow control tools and (ii) the integration of those tools into paper microfluidic devices. Further, we strive to be comprehensive in our presentation and provide historical context through discussion and performance comparisons, when possible, of both relevant earlier work and recent work. Finally, we discuss the major areas of focus for fluid flow methods development to advance the potential of paper microfluidics for high-performance field applications.

Surface acoustic wave microfluidics

PubMed Central

Ding, Xiaoyun; Li, Peng; Lin, Sz-Chin Steven; Stratton, Zackary S.; Nama, Nitesh; Guo, Feng; Slotcavage, Daniel; Mao, Xiaole; Shi, Jinjie; Costanzo, Francesco; Huang, Tony Jun

2014-01-01

The recent introduction of surface acoustic wave (SAW) technology onto lab-on-a-chip platforms has opened a new frontier in microfluidics. The advantages provided by such SAW microfluidics are numerous: simple fabrication, high biocompatibility, fast fluid actuation, versatility, compact and inexpensive devices and accessories, contact-free particle manipulation, and compatibility with other microfluidic components. We believe that these advantages enable SAW microfluidics to play a significant role in a variety of applications in biology, chemistry, engineering, and medicine. In this review article, we discuss the theory underpinning SAWs and their interactions with particles and the contacting fluids in which they are suspended. We then review the SAW-enabled microfluidic devices demonstrated to date, starting with devices that accomplish fluid mixing and transport through the use of travelling SAW; we follow that by reviewing the more recent innovations achieved with standing SAW that enable such actions as particle/cell focusing, sorting, and patterning. Finally, we look forward and appraise where the discipline of SAW microfluidics could go next. PMID:23900527

Development of a Pressure Switched Microfluidic Cell Sorter

NASA Astrophysics Data System (ADS)

Ozbay, Baris; Jones, Alex; Gibson, Emily

2009-10-01

Lab on a chip technology allows for the replacement of traditional cell sorters with microfluidic devices which can be produced less expensively and are more compact. Additionally, the compact nature of microfluidic cell sorters may lead to the realization of their application in point-of-care medical devices. Though techniques have been demonstrated previously for sorting in microfluidic devices with optical or electro-osmotic switching, both of these techniques are expensive and more difficult to implement than pressure switching. This microfluidic cell sorter design also allows for easy integration with optical spectroscopy for identification of cell type. Our current microfluidic device was fabricated with polydimethylsiloxane (PDMS), a polymer that houses the channels, which is then chemically bonded to a glass slide. The flow of fluid through the device is controlled by pressure controllers, and the switching of the cells is accomplished with the use of a high performance pressure controller interfaced with a computer. The cells are fed through the channels with the use of hydrodynamic focusing techniques. Once the experimental setup is fully functional the objective will be to determine switching rates, explore techniques to optimize these rates, and experiment with sorting of other biomolecules including DNA.

Microfluidic Diatomite Analytical Devices for Illicit Drug Sensing with ppb-Level Sensitivity.

PubMed

Kong, Xianming; Chong, Xinyuan; Squire, Kenny; Wang, Alan X

2018-04-15

The escalating research interests in porous media microfluidics, such as microfluidic paper-based analytical devices, have fostered a new spectrum of biomedical devices for point-of-care (POC) diagnosis and biosensing. In this paper, we report microfluidic diatomite analytical devices (μDADs), which consist of highly porous photonic crystal biosilica channels, as an innovative lab-on-a-chip platform to detect illicit drugs. The μDADs in this work are fabricated by spin-coating and tape-stripping diatomaceous earth on regular glass slides with cross section of 400×30µm 2 . As the most unique feature, our μDADs can simultaneously perform on-chip chromatography to separate small molecules from complex biofluidic samples and acquire the surface-enhanced Raman scattering spectra of the target chemicals with high specificity. Owing to the ultra-small dimension of the diatomite microfluidic channels and the photonic crystal effect from the fossilized diatom frustules, we demonstrate unprecedented sensitivity down to part-per-billion (ppb) level when detecting pyrene (1ppb) from mixed sample with Raman dye and cocaine (10 ppb) from human plasma. This pioneering work proves the exclusive advantage of μDADs as emerging microfluidic devices for chemical and biomedical sensing, especially for POC drug screening.

Microfluidic assembly blocks.

PubMed

Rhee, Minsoung; Burns, Mark A

2008-08-01

An assembly approach for microdevice construction using prefabricated microfluidic components is presented. Although microfluidic systems are convenient platforms for biological assays, their use in the life sciences is still limited mainly due to the high-level fabrication expertise required for construction. This approach involves prefabrication of individual microfluidic assembly blocks (MABs) in PDMS that can be readily assembled to form microfluidic systems. Non-expert users can assemble the blocks on glass slides to build their devices in minutes without any fabrication steps. In this paper, we describe the construction and assembly of the devices using the MAB methodology, and demonstrate common microfluidic applications including laminar flow development, valve control, and cell culture.

Absolute quantification of DNA methylation using microfluidic chip-based digital PCR.

PubMed

Wu, Zhenhua; Bai, Yanan; Cheng, Zule; Liu, Fangming; Wang, Ping; Yang, Dawei; Li, Gang; Jin, Qinghui; Mao, Hongju; Zhao, Jianlong

2017-10-15

Hypermethylation of CpG islands in the promoter region of many tumor suppressor genes downregulates their expression and in a result promotes tumorigenesis. Therefore, detection of DNA methylation status is a convenient diagnostic tool for cancer detection. Here, we reported a novel method for the integrative detection of methylation by the microfluidic chip-based digital PCR. This method relies on methylation-sensitive restriction enzyme HpaII, which cleaves the unmethylated DNA strands while keeping the methylated ones intact. After HpaII treatment, the DNA methylation level is determined quantitatively by the microfluidic chip-based digital PCR with the lower limit of detection equal to 0.52%. To validate the applicability of this method, promoter methylation of two tumor suppressor genes (PCDHGB6 and HOXA9) was tested in 10 samples of early stage lung adenocarcinoma and their adjacent non-tumorous tissues. The consistency was observed in the analysis of these samples using our method and a conventional bisulfite pyrosequencing. Combining high sensitivity and low cost, the microfluidic chip-based digital PCR method might provide a promising alternative for the detection of DNA methylation and early diagnosis of epigenetics-related diseases. Copyright © 2017 Elsevier B.V. All rights reserved.

Inventions Utilizing Microfluidics and Colloidal Particles

NASA Technical Reports Server (NTRS)

Marr, David W.; Gong, Tieying; Oakey, John; Terray, Alexander V.; Wu, David T.

2009-01-01

Several related inventions pertain to families of devices that utilize microfluidics and/or colloidal particles to obtain useful physical effects. The families of devices can be summarized as follows: (1) Microfluidic pumps and/or valves wherein colloidal-size particles driven by electrical, magnetic, or optical fields serve as the principal moving parts that propel and/or direct the affected flows. (2) Devices that are similar to the aforementioned pumps and/or valves except that they are used to manipulate light instead of fluids. The colloidal particles in these devices are substantially constrained to move in a plane and are driven to spatially order them into arrays that function, variously, as waveguides, filters, or switches for optical signals. (3) Devices wherein the ultra-laminar nature of microfluidic flows is exploited to effect separation, sorting, or filtering of colloidal particles or biological cells in suspension. (4) Devices wherein a combination of confinement and applied electrical and/or optical fields forces the colloidal particles to become arranged into three-dimensional crystal lattices. Control of the colloidal crystalline structures could be exploited to control diffraction of light. (5) Microfluidic devices, incorporating fluid waveguides, wherein switching of flows among different paths would be accompanied by switching of optical signals.

All-electronic droplet generation on-chip with real-time feedback control for EWOD digital microfluidics.

PubMed

Gong, Jian; Kim, Chang-Jin C J

2008-06-01

Electrowetting-on-dielectric (EWOD) actuation enables digital (or droplet) microfluidics where small packets of liquids are manipulated on a two-dimensional surface. Due to its mechanical simplicity and low energy consumption, EWOD holds particular promise for portable systems. To improve volume precision of the droplets, which is desired for quantitative applications such as biochemical assays, existing practices would require near-perfect device fabrication and operation conditions unless the droplets are generated under feedback control by an extra pump setup off of the chip. In this paper, we develop an all-electronic (i.e., no ancillary pumping) real-time feedback control of on-chip droplet generation. A fast voltage modulation, capacitance sensing, and discrete-time PID feedback controller are integrated on the operating electronic board. A significant improvement is obtained in the droplet volume uniformity, compared with an open loop control as well as the previous feedback control employing an external pump. Furthermore, this new capability empowers users to prescribe the droplet volume even below the previously considered minimum, allowing, for example, 1 : x (x < 1) mixing, in comparison to the previously considered n : m mixing (i.e., n and m unit droplets).

Custom 3D printer and resin for 18 μm × 20 μm microfluidic flow channels.

PubMed

Gong, Hua; Bickham, Bryce P; Woolley, Adam T; Nordin, Gregory P

2017-08-22

While there is great interest in 3D printing for microfluidic device fabrication, to-date the achieved feature sizes have not been in the truly microfluidic regime (<100 μm). In this paper we demonstrate that a custom digital light processor stereolithographic (DLP-SLA) 3D printer and a specifically-designed, low cost, custom resin can readily achieve flow channel cross sections as small as 18 μm × 20 μm. Our 3D printer has a projected image plane resolution of 7.6 μm and uses a 385 nm LED, which dramatically increases the available selection of UV absorbers for resin formulation compared to 3D printers with 405 nm LEDs. Beginning with 20 candidate absorbers, we demonstrate the evaluation criteria and process flow required to develop a high-resolution resin. In doing so, we introduce a new mathematical model for characterizing the resin optical penetration depth based only on measurement of the absorber's molar absorptivity. Our final resin formulation uses 2-nitrophenyl phenyl sulfide (NPS) as the UV absorber. We also develop a novel channel narrowing technique that, together with the new resin and 3D printer resolution, enables small flow channel fabrication. We demonstrate the efficacy of our approach by fabricating 3D serpentine flow channels 41 mm long in a volume of only 0.12 mm 3 , and by printing high aspect ratio flow channels <25 μm wide and 3 mm tall. These results indicate that 3D printing is finally positioned to challenge the pre-eminence of methods such as soft lithography for microfluidic device prototyping and fabrication.

Microfluidic device, and related methods

NASA Technical Reports Server (NTRS)

Wong, Eric W. (Inventor)

2010-01-01

A method of making a microfluidic device is provided. The method features patterning a permeable wall on a substrate, and surrounding the permeable wall with a solid, non-permeable boundary structure to establish a microfluidic channel having a cross-sectional dimension less than 5,000 microns and a cross-sectional area at least partially filled with the permeable wall so that fluid flowing through the microfluidic channel at least partially passes through the permeable wall.

Diffusion phenomena of cells and biomolecules in microfluidic devices.

PubMed

Yildiz-Ozturk, Ece; Yesil-Celiktas, Ozlem

2015-09-01

Biomicrofluidics is an emerging field at the cross roads of microfluidics and life sciences which requires intensive research efforts in terms of introducing appropriate designs, production techniques, and analysis. The ultimate goal is to deliver innovative and cost-effective microfluidic devices to biotech, biomedical, and pharmaceutical industries. Therefore, creating an in-depth understanding of the transport phenomena of cells and biomolecules becomes vital and concurrently poses significant challenges. The present article outlines the recent advancements in diffusion phenomena of cells and biomolecules by highlighting transport principles from an engineering perspective, cell responses in microfluidic devices with emphases on diffusion- and flow-based microfluidic gradient platforms, macroscopic and microscopic approaches for investigating the diffusion phenomena of biomolecules, microfluidic platforms for the delivery of these molecules, as well as the state of the art in biological applications of mammalian cell responses and diffusion of biomolecules.

Advances in microfluidic devices made from thermoplastics used in cell biology and analyses.

PubMed

Gencturk, Elif; Mutlu, Senol; Ulgen, Kutlu O

2017-09-01

Silicon and glass were the main fabrication materials of microfluidic devices, however, plastics are on the rise in the past few years. Thermoplastic materials have recently been used to fabricate microfluidic platforms to perform experiments on cellular studies or environmental monitoring, with low cost disposable devices. This review describes the present state of the development and applications of microfluidic systems used in cell biology and analyses since the year 2000. Cultivation, separation/isolation, detection and analysis, and reaction studies are extensively discussed, considering only microorganisms (bacteria, yeast, fungi, zebra fish, etc.) and mammalian cell related studies in the microfluidic platforms. The advantages/disadvantages, fabrication methods, dimensions, and the purpose of creating the desired system are explained in detail. An important conclusion of this review is that these microfluidic platforms are still open for research and development, and solutions need to be found for each case separately.

Diffusion phenomena of cells and biomolecules in microfluidic devices

PubMed Central

Yildiz-Ozturk, Ece; Yesil-Celiktas, Ozlem

2015-01-01

Biomicrofluidics is an emerging field at the cross roads of microfluidics and life sciences which requires intensive research efforts in terms of introducing appropriate designs, production techniques, and analysis. The ultimate goal is to deliver innovative and cost-effective microfluidic devices to biotech, biomedical, and pharmaceutical industries. Therefore, creating an in-depth understanding of the transport phenomena of cells and biomolecules becomes vital and concurrently poses significant challenges. The present article outlines the recent advancements in diffusion phenomena of cells and biomolecules by highlighting transport principles from an engineering perspective, cell responses in microfluidic devices with emphases on diffusion- and flow-based microfluidic gradient platforms, macroscopic and microscopic approaches for investigating the diffusion phenomena of biomolecules, microfluidic platforms for the delivery of these molecules, as well as the state of the art in biological applications of mammalian cell responses and diffusion of biomolecules. PMID:26180576

Microfluidics and Coagulation Biology

PubMed Central

Colace, Thomas V.; Tormoen, Garth W.

2014-01-01

The study of blood ex vivo can occur in closed or open systems, with or without flow. Microfluidic devices facilitate measurements of platelet function, coagulation biology, cellular biorheology, adhesion dynamics, pharmacology, and clinical diagnostics. An experimental session can accommodate 100s to 1000s of unique clotting events. Using microfluidics, thrombotic events can be studied on defined surfaces of biopolymers, matrix proteins, and tissue factor under constant flow rate or constant pressure drop conditions. Distinct shear rates can be created on a device with a single perfusion pump. Microfluidic devices facilitated the determination of intraluminal thrombus permeability and the discovery that platelet contractility can be activated by a sudden decrease in flow. Microfluidics are ideal for multicolor imaging of platelets, fibrin, and phosphatidylserine and provide a human blood analog to the mouse injury models. Overall, microfluidic advances offer many opportunities for research, drug testing under relevant hemodynamic conditions, and clinical diagnostics. PMID:23642241

Use of Vacuum Bagging for Fabricating Thermoplastic Microfluidic Devices

PubMed Central

Cassano, Christopher L.; Simon, Andrew J.; Liu, Wei; Fredrickson, Carl; Fan, Z. Hugh

2014-01-01

In this work we present a novel thermal bonding method for thermoplastic microfluidic devices. This simple method employs a modified vacuum bagging technique, a concept borrowed from the aerospace industry, to produce conventional thick substrate microfluidic devices, as well as multi-layer film devices. The bonds produced using this method are superior to those obtained using conventional thermal bonding methods, including thermal lamination, and are capable of sustaining burst pressures in excess of 550 kPa. To illustrate the utility of this method, thick substrate devices were produced, as well as a six-layer film device that incorporated several complex features. PMID:25329244

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

PubMed

Koo, Hyung-Jun; Velev, Orlin D

2013-05-09

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

Additive manufacturing of three-dimensional (3D) microfluidic-based microelectromechanical systems (MEMS) for acoustofluidic applications.

PubMed

Cesewski, Ellen; Haring, Alexander P; Tong, Yuxin; Singh, Manjot; Thakur, Rajan; Laheri, Sahil; Read, Kaitlin A; Powell, Michael D; Oestreich, Kenneth J; Johnson, Blake N

2018-06-13

Three-dimensional (3D) printing now enables the fabrication of 3D structural electronics and microfluidics. Further, conventional subtractive manufacturing processes for microelectromechanical systems (MEMS) relatively limit device structure to two dimensions and require post-processing steps for interface with microfluidics. Thus, the objective of this work is to create an additive manufacturing approach for fabrication of 3D microfluidic-based MEMS devices that enables 3D configurations of electromechanical systems and simultaneous integration of microfluidics. Here, we demonstrate the ability to fabricate microfluidic-based acoustofluidic devices that contain orthogonal out-of-plane piezoelectric sensors and actuators using additive manufacturing. The devices were fabricated using a microextrusion 3D printing system that contained integrated pick-and-place functionality. Additively assembled materials and components included 3D printed epoxy, polydimethylsiloxane (PDMS), silver nanoparticles, and eutectic gallium-indium as well as robotically embedded piezoelectric chips (lead zirconate titanate (PZT)). Electrical impedance spectroscopy and finite element modeling studies showed the embedded PZT chips exhibited multiple resonant modes of varying mode shape over the 0-20 MHz frequency range. Flow visualization studies using neutrally buoyant particles (diameter = 0.8-70 μm) confirmed the 3D printed devices generated bulk acoustic waves (BAWs) capable of size-selective manipulation, trapping, and separation of suspended particles in droplets and microchannels. Flow visualization studies in a continuous flow format showed suspended particles could be moved toward or away from the walls of microfluidic channels based on selective actuation of in-plane or out-of-plane PZT chips. This work suggests additive manufacturing potentially provides new opportunities for the design and fabrication of acoustofluidic and microfluidic devices.

Microfluidic electronics.

PubMed

Cheng, Shi; Wu, Zhigang

2012-08-21

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

Efficient gas-liquid contact using microfluidic membrane devices with staggered herringbone mixers.

PubMed

Femmer, Tim; Eggersdorfer, Max L; Kuehne, Alexander J C; Wessling, Matthias

2015-08-07

We describe a novel membrane based gas-liquid-contacting device with increased mass transport and reduced pressure loss by combining a membrane with a staggered herringbone static mixer. Herringbone structures are imposed on the microfluidic channel geometry via soft lithography, acting as mixers which introduce secondary flows at the membrane interface. Such flows include Dean vortices and Taylor flows generating effective mixing while improving mass transport and preventing concentration polarization in microfluidic channels. Furthermore, our static herringbone mixer membranes effectively reduce pressure losses leading to devices with enhanced transfer properties for microfluidic gas-liquid contact. We investigate the red blood cell distribution to tailor our devices towards miniaturised extracorporeal membrane oxygenation and improved comfort of patients with lung insufficiencies.

Droplet Microfluidic Device Fabrication and Use for Isothermal Amplification and Detection of MicroRNA.

PubMed

Giuffrida, Maria Chiara; D'Agata, Roberta; Spoto, Giuseppe

2017-01-01

Droplet microfluidics combined with the isothermal circular strand displacement polymerization (ICSDP) represents a powerful new technique to detect both single-stranded DNA and microRNA sequences. The method here described helps in overcoming some drawbacks of the lately introduced droplet polymerase chain reaction (PCR) amplification when implemented in microfluidic devices. The method also allows the detection of nanoliter droplets of nucleic acids sequences solutions, with a particular attention to microRNA sequences that are detected at the picomolar level. The integration of the ICSDP amplification protocol in droplet microfluidic devices reduces the time of analysis and the amount of sample required. In addition, there is also the possibility to design parallel analyses to be integrated in portable devices.

Comparison of separation performance of laser-ablated and wet-etched microfluidic devices

PubMed Central

Baker, Christopher A.; Bulloch, Rayford; Roper, Michael G.

2010-01-01

Laser ablation of glass allows for production of microfluidic devices without the need of hydrofluoric acid and photolithography. The goal of this study was to compare the separation performance of microfluidic devices produced using a low-cost laser ablation system and conventional wet etching. During laser ablation, cracking of the glass substrate was prevented by heating the glass to 300°C. A range of laser energy densities was found to produce channel depths ranging from 4 – 35 μm and channel widths from 118 – 162 μm. The electroosmotic flow velocity was lower in laser-ablated devices, 0.110 ± 0.005 cm s−1, as compared to wet-etched microfluidic chips, 0.126 ± 0.003 cm s−1. Separations of both small and large molecules performed on both wet- and laser-ablated devices were compared by examining limits of detection, theoretical plate count, and peak asymmetry. Laser-induced fluorescence detection limits were 10 pM fluorescein for both types of devices. Laser-ablated and wet-etched microfluidic chips had reproducible migration times with ≤ 2.8% RSD and peak asymmetries ranging from 1.0 – 1.8. Numbers of theoretical plates were between 2.8- and 6.2-fold higher on the wet-etched devices compared to laser-ablated devices. Nevertheless, resolution between small and large analytes was accomplished, which indicates that laser ablation may find an application in pedagogical studies of electrophoresis or microfluidic devices, or in settings where hydrofluoric acid cannot be used. PMID:20827468

Engineering and evaluating drug delivery particles in microfluidic devices.

PubMed

Björnmalm, Mattias; Yan, Yan; Caruso, Frank

2014-09-28

The development of new and improved particle-based drug delivery is underpinned by an enhanced ability to engineer particles with high fidelity and integrity, as well as increased knowledge of their biological performance. Microfluidics can facilitate these processes through the engineering of spatiotemporally highly controlled environments using designed microstructures in combination with physical phenomena present at the microscale. In this review, we discuss microfluidics in the context of addressing key challenges in particle-based drug delivery. We provide an overview of how microfluidic devices can: (i) be employed to engineer particles, by providing highly controlled interfaces, and (ii) be used to establish dynamic in vitro models that mimic in vivo environments for studying the biological behavior of engineered particles. Finally, we discuss how the flexible and modular nature of microfluidic devices provides opportunities to create increasingly realistic models of the in vivo milieu (including multi-cell, multi-tissue and even multi-organ devices), and how ongoing developments toward commercialization of microfluidic tools are opening up new opportunities for the engineering and evaluation of drug delivery particles. Copyright © 2014 Elsevier B.V. All rights reserved.

Manufacture of micro fluidic devices by laser welding using thermal transfer printing techniques

NASA Astrophysics Data System (ADS)

Klein, R.; Klein, K. F.; Tobisch, T.; Thoelken, D.; Belz, M.

2016-03-01

Micro-fluidic devices are widely used today in the areas of medical diagnostics and drug research, as well as for applications within the process, electronics and chemical industry. Microliters of fluids or single cell to cell interactions can be conveniently analyzed with such devices using fluorescence imaging, phase contrast microscopy or spectroscopic techniques. Typical micro-fluidic devices consist of a thermoplastic base component with chambers and channels covered by a hermetic fluid and gas tight sealed lid component. Both components are usually from the same or similar thermoplastic material. Different mechanical, adhesive or thermal joining processes can be used to assemble base component and lid. Today, laser beam welding shows the potential to become a novel manufacturing opportunity for midsize and large scale production of micro-fluidic devices resulting in excellent processing quality by localized heat input and low thermal stress to the device during processing. For laser welding, optical absorption of the resin and laser wavelength has to be matched for proper joining. This paper will focus on a new approach to prepare micro-fluidic channels in such devices using a thermal transfer printing process, where an optical absorbing layer absorbs the laser energy. Advantages of this process will be discussed in combination with laser welding of optical transparent micro-fluidic devices.

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.

Microfluidic device for chemical and mechanical manipulation of suspended cells

NASA Astrophysics Data System (ADS)

Rezvani, Samaneh; Shi, Nan; Squires, Todd M.; Schmidt, Christoph F.

2018-01-01

Microfluidic devices have proven to be useful and versatile for cell studies. We here report on a method to adapt microfluidic stickers made from UV-curable optical adhesive with inserted permeable hydrogel membrane micro-windows for mechanical studies of suspended cells. The windows were fabricated by optical projection lithography using scanning confocal microscopy. The device allows us to rapidly exchange embedding medium while observing and probing the cells. We characterize the device and demonstrate the function by exposing cultured fibroblasts to varying osmotic conditions. Cells can be shrunk reversibly under osmotic compression.

Incorporation of prefabricated screw, pneumatic, and solenoid valves into microfluidic devices

PubMed Central

Hulme, S. Elizabeth; Shevkoplyas, Sergey S.

2011-01-01

This paper describes a method for prefabricating screw, pneumatic, and solenoid valves and embedding them in microfluidic devices. This method of prefabrication and embedding is simple, requires no advanced fabrication, and is compatible with soft lithography. Because prefabrication allows many identical valves to be made at one time, the performance across different valves made in the same manner is reproducible. In addition, the performance of a single valve is reproducible over many cycles of opening and closing: an embedded solenoid valve opened and closed a microfluidic channel more than 100,000 times with no apparent deterioration in its function. It was possible to combine all three types of prefabricated valves in a single microfluidic device to control chemical gradients in a microfluidic channel temporally and spatially. PMID:19209338

Microfluidic cell chips for high-throughput drug screening

PubMed Central

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

2016-01-01

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

Incorporation of prefabricated screw, pneumatic, and solenoid valves into microfluidic devices.

PubMed

Hulme, S Elizabeth; Shevkoplyas, Sergey S; Whitesides, George M

2009-01-07

This paper describes a method for prefabricating screw, pneumatic, and solenoid valves and embedding them in microfluidic devices. This method of prefabrication and embedding is simple, requires no advanced fabrication, and is compatible with soft lithography. Because prefabrication allows many identical valves to be made at one time, the performance across different valves made in the same manner is reproducible. In addition, the performance of a single valve is reproducible over many cycles of opening and closing: an embedded solenoid valve opened and closed a microfluidic channel more than 100,000 times with no apparent deterioration in its function. It was possible to combine all three types of prefabricated valves in a single microfluidic device to control chemical gradients in a microfluidic channel temporally and spatially.

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

PubMed Central

Chung, Bong Geun; Park, Jeong Won; Hu, Jia Sheng; Huang, Carlos; Monuki, Edwin S; Jeon, Noo Li

2007-01-01

Background Microfluidics is an enabling technology with a number of advantages over traditional tissue culture methods when precise control of cellular microenvironment is required. However, there are a number of practical and technical limitations that impede wider implementation in routine biomedical research. Specialized equipment and protocols required for fabrication and setting up microfluidic experiments present hurdles for routine use by most biology laboratories. Results We have developed and validated a novel microfluidic device that can directly interface with conventional tissue culture methods to generate and maintain controlled soluble environments in a Petri dish. It incorporates separate sets of fluidic channels and vacuum networks on a single device that allows reversible application of microfluidic gradients onto wet cell culture surfaces. Stable, precise concentration gradients of soluble factors were generated using simple microfluidic channels that were attached to a perfusion system. We successfully demonstrated real-time optical live/dead cell imaging of neural stem cells exposed to a hydrogen peroxide gradient and chemotaxis of metastatic breast cancer cells in a growth factor gradient. Conclusion This paper describes the design and application of a versatile microfluidic device that can directly interface with conventional cell culture methods. This platform provides a simple yet versatile tool for incorporating the advantages of a microfluidic approach to biological assays without changing established tissue culture protocols. PMID:17883868

Three-Dimensional Printing Based Hybrid Manufacturing of Microfluidic Devices.

PubMed

Alapan, Yunus; Hasan, Muhammad Noman; Shen, Richang; Gurkan, Umut A

2015-05-01

Microfluidic platforms offer revolutionary and practical solutions to challenging problems in biology and medicine. Even though traditional micro/nanofabrication technologies expedited the emergence of the microfluidics field, recent advances in advanced additive manufacturing hold significant potential for single-step, stand-alone microfluidic device fabrication. One such technology, which holds a significant promise for next generation microsystem fabrication is three-dimensional (3D) printing. Presently, building 3D printed stand-alone microfluidic devices with fully embedded microchannels for applications in biology and medicine has the following challenges: (i) limitations in achievable design complexity, (ii) need for a wider variety of transparent materials, (iii) limited z-resolution, (iv) absence of extremely smooth surface finish, and (v) limitations in precision fabrication of hollow and void sections with extremely high surface area to volume ratio. We developed a new way to fabricate stand-alone microfluidic devices with integrated manifolds and embedded microchannels by utilizing a 3D printing and laser micromachined lamination based hybrid manufacturing approach. In this new fabrication method, we exploit the minimized fabrication steps enabled by 3D printing, and reduced assembly complexities facilitated by laser micromachined lamination method. The new hybrid fabrication method enables key features for advanced microfluidic system architecture: (i) increased design complexity in 3D, (ii) improved control over microflow behavior in all three directions and in multiple layers, (iii) transverse multilayer flow and precisely integrated flow distribution, and (iv) enhanced transparency for high resolution imaging and analysis. Hybrid manufacturing approaches hold great potential in advancing microfluidic device fabrication in terms of standardization, fast production, and user-independent manufacturing.

Three-Dimensional Printing Based Hybrid Manufacturing of Microfluidic Devices

PubMed Central

Shen, Richang; Gurkan, Umut A.

2016-01-01

Microfluidic platforms offer revolutionary and practical solutions to challenging problems in biology and medicine. Even though traditional micro/nanofabrication technologies expedited the emergence of the microfluidics field, recent advances in advanced additive manufacturing hold significant potential for single-step, stand-alone microfluidic device fabrication. One such technology, which holds a significant promise for next generation microsystem fabrication is three-dimensional (3D) printing. Presently, building 3D printed stand-alone microfluidic devices with fully embedded microchannels for applications in biology and medicine has the following challenges: (i) limitations in achievable design complexity, (ii) need for a wider variety of transparent materials, (iii) limited z-resolution, (iv) absence of extremely smooth surface finish, and (v) limitations in precision fabrication of hollow and void sections with extremely high surface area to volume ratio. We developed a new way to fabricate stand-alone microfluidic devices with integrated manifolds and embedded microchannels by utilizing a 3D printing and laser micromachined lamination based hybrid manufacturing approach. In this new fabrication method, we exploit the minimized fabrication steps enabled by 3D printing, and reduced assembly complexities facilitated by laser micromachined lamination method. The new hybrid fabrication method enables key features for advanced microfluidic system architecture: (i) increased design complexity in 3D, (ii) improved control over microflow behavior in all three directions and in multiple layers, (iii) transverse multilayer flow and precisely integrated flow distribution, and (iv) enhanced transparency for high resolution imaging and analysis. Hybrid manufacturing approaches hold great potential in advancing microfluidic device fabrication in terms of standardization, fast production, and user-independent manufacturing. PMID:27512530

Microfabrication and Applications of Opto-Microfluidic Sensors

PubMed Central

Zhang, Daiying; Men, Liqiu; Chen, Qiying

2011-01-01

A review of research activities on opto-microfluidic sensors carried out by the research groups in Canada is presented. After a brief introduction of this exciting research field, detailed discussion is focused on different techniques for the fabrication of opto-microfluidic sensors, and various applications of these devices for bioanalysis, chemical detection, and optical measurement. Our current research on femtosecond laser microfabrication of optofluidic devices is introduced and some experimental results are elaborated. The research on opto-microfluidics provides highly sensitive opto-microfluidic sensors for practical applications with significant advantages of portability, efficiency, sensitivity, versatility, and low cost. PMID:22163904

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

Clear Castable Polyurethane Elastomer for Fabrication of Microfluidic Devices

PubMed Central

Domansky, Karel; Leslie, Daniel C.; McKinney, James; Fraser, Jacob P.; Sliz, Josiah D.; Hamkins-Indik, Tiama; Hamilton, Geraldine A.; Bahinski, Anthony; Ingber, Donald E.

2013-01-01

Polydimethylsiloxane (PDMS) has numerous desirable properties for fabricating microfluidic devices, including optical transparency, flexibility, biocompatibility, and fabrication by casting; however, partitioning of small hydrophobic molecules into the bulk of PDMS hinders industrial acceptance of PDMS microfluidic devices for chemical processing and drug development applications. Here we describe an attractive alternative material that is similar to PDMS in terms of optical transparency, flexibility and castability, but that is also resistant to absorption of small hydrophobic molecules. PMID:23954953

Microfluidic chemical reaction circuits

DOEpatents

Lee, Chung-cheng [Irvine, CA; Sui, Guodong [Los Angeles, CA; Elizarov, Arkadij [Valley Village, CA; Kolb, Hartmuth C [Playa del Rey, CA; Huang, Jiang [San Jose, CA; Heath, James R [South Pasadena, CA; Phelps, Michael E [Los Angeles, CA; Quake, Stephen R [Stanford, CA; Tseng, Hsian-rong [Los Angeles, CA; Wyatt, Paul [Tipperary, IE; Daridon, Antoine [Mont-Sur-Rolle, CH

2012-06-26

New microfluidic devices, useful for carrying out chemical reactions, are provided. The devices are adapted for on-chip solvent exchange, chemical processes requiring multiple chemical reactions, and rapid concentration of reagents.

Development of a 3D printer using scanning projection stereolithography

PubMed Central

Lee, Michael P.; Cooper, Geoffrey J. T.; Hinkley, Trevor; Gibson, Graham M.; Padgett, Miles J.; Cronin, Leroy

2015-01-01

We have developed a system for the rapid fabrication of low cost 3D devices and systems in the laboratory with micro-scale features yet cm-scale objects. Our system is inspired by maskless lithography, where a digital micromirror device (DMD) is used to project patterns with resolution up to 10 µm onto a layer of photoresist. Large area objects can be fabricated by stitching projected images over a 5cm2 area. The addition of a z-stage allows multiple layers to be stacked to create 3D objects, removing the need for any developing or etching steps but at the same time leading to true 3D devices which are robust, configurable and scalable. We demonstrate the applications of the system by printing a range of micro-scale objects as well as a fully functioning microfluidic droplet device and test its integrity by pumping dye through the channels. PMID:25906401

A piezo-ring-on-chip microfluidic device for simple and low-cost mass spectrometry interfacing.

PubMed

Tsao, Chia-Wen; Lei, I-Chao; Chen, Pi-Yu; Yang, Yu-Liang

2018-02-12

Mass spectrometry (MS) interfacing technology provides the means for incorporating microfluidic processing with post MS analysis. In this study, we propose a simple piezo-ring-on-chip microfluidic device for the controlled spraying of MALDI-MS targets. This device uses a low-cost, commercially-available ring-shaped piezoelectric acoustic atomizer (piezo-ring) directly integrated into a polydimethylsiloxane microfluidic device to spray the sample onto the MS target substrate. The piezo-ring-on-chip microfluidic device's design, fabrication, and actuation, and its pulsatile pumping effects were evaluated. The spraying performance was examined by depositing organic matrix samples onto the MS target substrate by using both an automatic linear motion motor, and manual deposition. Matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) was performed to analyze the peptide samples on the MALDI target substrates. Using our technique, model peptides with 10 -6 M concentration can be successfully detected. The results also indicate that the piezo-ring-on-chip approach forms finer matrix crystals and presents better MS signal uniformity with little sample consumption compared to the conventional pipetting method.

Cost-effective rapid prototyping and assembly of poly(methyl methacrylate) microfluidic devices.

PubMed

Matellan, Carlos; Del Río Hernández, Armando E

2018-05-03

The difficulty in translating conventional microfluidics from laboratory prototypes to commercial products has shifted research efforts towards thermoplastic materials for their higher translational potential and amenability to industrial manufacturing. Here, we present an accessible method to fabricate and assemble polymethyl methacrylate (PMMA) microfluidic devices in a "mask-less" and cost-effective manner that can be applied to manufacture a wide range of designs due to its versatility. Laser micromachining offers high flexibility in channel dimensions and morphology by controlling the laser properties, while our two-step surface treatment based on exposure to acetone vapour and low-temperature annealing enables improvement of the surface quality without deformation of the device. Finally, we demonstrate a capillarity-driven adhesive delivery bonding method that can produce an effective seal between PMMA devices and a variety of substrates, including glass, silicon and LiNbO 3 . We illustrate the potential of this technique with two microfluidic devices, an H-filter and a droplet generator. The technique proposed here offers a low entry barrier for the rapid prototyping of thermoplastic microfluidics, enabling iterative design for laboratories without access to conventional microfabrication equipment.

Optical Manipulation of Single Magnetic Beads in a Microwell Array on a Digital Microfluidic Chip.

PubMed

Decrop, Deborah; Brans, Toon; Gijsenbergh, Pieter; Lu, Jiadi; Spasic, Dragana; Kokalj, Tadej; Beunis, Filip; Goos, Peter; Puers, Robert; Lammertyn, Jeroen

2016-09-06

The detection of single molecules in magnetic microbead microwell array formats revolutionized the development of digital bioassays. However, retrieval of individual magnetic beads from these arrays has not been realized until now despite having great potential for studying captured targets at the individual level. In this paper, optical tweezers were implemented on a digital microfluidic platform for accurate manipulation of single magnetic beads seeded in a microwell array. Successful optical trapping of magnetic beads was found to be dependent on Brownian motion of the beads, suggesting a 99% chance of trapping a vibrating bead. A tailor-made experimental design was used to screen the effect of bead type, ionic buffer strength, surfactant type, and concentration on the Brownian activity of beads in microwells. With the optimal conditions, the manipulation of magnetic beads was demonstrated by their trapping, retrieving, transporting, and repositioning to a desired microwell on the array. The presented platform combines the strengths of digital microfluidics, digital bioassays, and optical tweezers, resulting in a powerful dynamic microwell array system for single molecule and single cell studies.

On demand nanoliter-scale microfluidic droplet generation, injection, and mixing using a passive microfluidic device

PubMed Central

Tangen, Uwe; Sharma, Abhishek

2015-01-01

We here present and characterize a programmable nanoliter scale droplet-on-demand device that can be used separately or readily integrated into low cost single layer rapid prototyping microfluidic systems for a wide range of user applications. The passive microfluidic device allows external (off-the-shelf) electronically controlled pinch valves to program the delivery of nanoliter scale aqueous droplets from up to 9 different inputs to a central outlet channel. The inputs can be either continuous aqueous fluid streams or microliter scale aqueous plugs embedded in a carrier fluid, in which case the number of effective input solutions that can be employed in an experiment is no longer strongly constrained (100 s–1000 s). Both nanoliter droplet sequencing output and nanoliter-scale droplet mixing are reported with this device. Optimization of the geometry and pressure relationships in the device was achieved in several hardware iterations with the support of open source microfluidic simulation software and equivalent circuit models. The requisite modular control of pressure relationships within the device is accomplished using hydrodynamic barriers and matched resistance channels with three different channel heights, custom parallel reversible microfluidic I/O connections, low dead-volume pinch valves, and a simply adjustable array of external screw valves. Programmable sequences of droplet mixes or chains of droplets can be achieved with the device at low Hz frequencies, limited by device elasticity, and could be further enhanced by valve integration. The chip has already found use in the characterization of droplet bunching during export and the synthesis of a DNA library. PMID:25759752

On demand nanoliter-scale microfluidic droplet generation, injection, and mixing using a passive microfluidic device.

PubMed

Tangen, Uwe; Sharma, Abhishek; Wagler, Patrick; McCaskill, John S

2015-01-01

We here present and characterize a programmable nanoliter scale droplet-on-demand device that can be used separately or readily integrated into low cost single layer rapid prototyping microfluidic systems for a wide range of user applications. The passive microfluidic device allows external (off-the-shelf) electronically controlled pinch valves to program the delivery of nanoliter scale aqueous droplets from up to 9 different inputs to a central outlet channel. The inputs can be either continuous aqueous fluid streams or microliter scale aqueous plugs embedded in a carrier fluid, in which case the number of effective input solutions that can be employed in an experiment is no longer strongly constrained (100 s-1000 s). Both nanoliter droplet sequencing output and nanoliter-scale droplet mixing are reported with this device. Optimization of the geometry and pressure relationships in the device was achieved in several hardware iterations with the support of open source microfluidic simulation software and equivalent circuit models. The requisite modular control of pressure relationships within the device is accomplished using hydrodynamic barriers and matched resistance channels with three different channel heights, custom parallel reversible microfluidic I/O connections, low dead-volume pinch valves, and a simply adjustable array of external screw valves. Programmable sequences of droplet mixes or chains of droplets can be achieved with the device at low Hz frequencies, limited by device elasticity, and could be further enhanced by valve integration. The chip has already found use in the characterization of droplet bunching during export and the synthesis of a DNA library.

Automated Microfluidic Instrument for Label-Free and High-Throughput Cell Separation.

PubMed

Zhang, Xinjie; Zhu, Zhixian; Xiang, Nan; Long, Feifei; Ni, Zhonghua

2018-03-20

Microfluidic technologies for cell separation were reported frequently in recent years. However, a compact microfluidic instrument enabling thoroughly automated cell separation is still rarely reported until today due to the difficult hybrid between the macrosized fluidic control system and the microsized microfluidic device. In this work, we propose a novel and automated microfluidic instrument to realize size-based separation of cancer cells in a label-free and high-throughput manner. Briefly, the instrument is equipped with a fully integrated microfluidic device and a set of robust fluid-driven and control units, and the instrument functions of precise fluid infusion and high-throughput cell separation are guaranteed by a flow regulatory chip and two cell separation chips which are the key components of the microfluidic device. With optimized control programs, the instrument is successfully applied to automatically sort human breast adenocarcinoma cell line MCF-7 from 5 mL of diluted human blood with a high recovery ratio of ∼85% within a rapid processing time of ∼23 min. We envision that our microfluidic instrument will be potentially useful in many biomedical applications, especially cell separation, enrichment, and concentration for the purpose of cell culture and analysis.

Biomarker detection for disease diagnosis using cost-effective microfluidic platforms.

PubMed

Sanjay, Sharma T; Fu, Guanglei; Dou, Maowei; Xu, Feng; Liu, Rutao; Qi, Hao; Li, XiuJun

2015-11-07

Early and timely detection of disease biomarkers can prevent the spread of infectious diseases, and drastically decrease the death rate of people suffering from different diseases such as cancer and infectious diseases. Because conventional diagnostic methods have limited application in low-resource settings due to the use of bulky and expensive instrumentation, simple and low-cost point-of-care diagnostic devices for timely and early biomarker diagnosis is the need of the hour, especially in rural areas and developing nations. The microfluidics technology possesses remarkable features for simple, low-cost, and rapid disease diagnosis. There have been significant advances in the development of microfluidic platforms for biomarker detection of diseases. This article reviews recent advances in biomarker detection using cost-effective microfluidic devices for disease diagnosis, with the emphasis on infectious disease and cancer diagnosis in low-resource settings. This review first introduces different microfluidic platforms (e.g. polymer and paper-based microfluidics) used for disease diagnosis, with a brief description of their common fabrication techniques. Then, it highlights various detection strategies for disease biomarker detection using microfluidic platforms, including colorimetric, fluorescence, chemiluminescence, electrochemiluminescence (ECL), and electrochemical detection. Finally, it discusses the current limitations of microfluidic devices for disease biomarker detection and future prospects.

Rapid Protein Separations in Microfluidic Devices

NASA Technical Reports Server (NTRS)

Fan, Z. H.; Das, Champak; Xia, Zheng; Stoyanov, Alexander V.; Fredrickson, Carl K.

2004-01-01

This paper describes fabrication of glass and plastic microfluidic devices for protein separations. Although the long-term goal is to develop a microfluidic device for two-dimensional gel electrophoresis, this paper focuses on the first dimension-isoelectric focusing (IEF). A laser-induced fluorescence (LIF) imaging system has been built for imaging an entire channel in an IEF device. The whole-channel imaging eliminates the need to migrate focused protein bands, which is required if a single-point detector is used. Using the devices and the imaging system, we are able to perform IEF separations of proteins within minutes rather than hours in traditional bench-top instruments.

Embellishment of microfluidic devices via femtosecond laser micronanofabrication for chip functionalization.

PubMed

Wang, Juan; He, Yan; Xia, Hong; Niu, Li-Gang; Zhang, Ran; Chen, Qi-Dai; Zhang, Yong-Lai; Li, Yan-Feng; Zeng, Shao-Jiang; Qin, Jian-Hua; Lin, Bing-Cheng; Sun, Hong-Bo

2010-08-07

This paper demonstrates the embellishment of existing microfluidic devices with integrated three dimensional (3D) micronanostructures via femtosecond laser micronanofabrication, which, for the first time, proves two-photon photopolymerization (TPP) to be a powerful technology for chip functionalization. As representative examples, microsieves with various pore shape and adjustable pore size were successfully fabricated inside a conventional glass-based microfluidic channel prepared by wet etching for microparticle separation. Moreover, a fish scale like microfilter was also fabricated and appointed as a one-way valve, which showed excellent performance as we expected. These results indicate that such embellishment of microfluidic devices is simple, low cost, flexible and easy to access. We believe that, combined with TPP, the application of lab-on-chip devices would be further extended.

3D printed microfluidics for biological applications.

PubMed

Ho, Chee Meng Benjamin; Ng, Sum Huan; Li, King Ho Holden; Yoon, Yong-Jin

2015-01-01

The term "Lab-on-a-Chip," is synonymous with describing microfluidic devices with biomedical applications. Even though microfluidics have been developing rapidly over the past decade, the uptake rate in biological research has been slow. This could be due to the tedious process of fabricating a chip and the absence of a "killer application" that would outperform existing traditional methods. In recent years, three dimensional (3D) printing has been drawing much interest from the research community. It has the ability to make complex structures with high resolution. Moreover, the fast building time and ease of learning has simplified the fabrication process of microfluidic devices to a single step. This could possibly aid the field of microfluidics in finding its "killer application" that will lead to its acceptance by researchers, especially in the biomedical field. In this paper, a review is carried out of how 3D printing helps to improve the fabrication of microfluidic devices, the 3D printing technologies currently used for fabrication and the future of 3D printing in the field of microfluidics.

PVDF Sensor Stimulated by Infrared Radiation for Temperature Monitoring in Microfluidic Devices.

PubMed

Pullano, Salvatore A; Mahbub, Ifana; Islam, Syed K; Fiorillo, Antonino S

2017-04-13

This paper presents a ferroelectric polymer-based temperature sensor designed for microfluidic devices. The integration of the sensor into a system-on-a-chip platform facilitates quick monitoring of localized temperature of a biological fluid, avoiding errors in the evaluation of thermal evolution of the fluid during analysis. The contact temperature sensor is fabricated by combining a thin pyroelectric film together with an infrared source, which stimulates the active element located on the top of the microfluidic channel. An experimental setup was assembled to validate the analytical model and to characterize the response rate of the device. The evaluation procedure and the operating range of the temperature also make this device suitable for applications where the localized temperature monitoring of biological samples is necessary. Additionally, ease of integration with standard microfluidic devices makes the proposed sensor an attractive option for in situ analysis of biological fluids.

Synthetic microfluidic paper: high surface area and high porosity polymer micropillar arrays.

PubMed

Hansson, Jonas; Yasuga, Hiroki; Haraldsson, Tommy; van der Wijngaart, Wouter

2016-01-21

We introduce Synthetic Microfluidic Paper, a novel porous material for microfluidic applications that consists of an OSTE polymer that is photostructured in a well-controlled geometry of slanted and interlocked micropillars. We demonstrate the distinct benefits of Synthetic Microfluidic Paper over other porous microfluidic materials, such as nitrocellulose, traditional paper and straight micropillar arrays: in contrast to straight micropillar arrays, the geometry of Synthetic Microfluidic Paper was miniaturized without suffering capillary collapse during manufacturing and fluidic operation, resulting in a six-fold increased internal surface area and a three-fold increased porous fraction. Compared to commercial nitrocellulose materials for capillary assays, Synthetic Microfluidic Paper shows a wider range of capillary pumping speed and four times lower device-to-device variation. Compared to the surfaces of the other porous microfluidic materials that are modified by adsorption, Synthetic Microfluidic Paper contains free thiol groups and has been shown to be suitable for covalent surface chemistry, demonstrated here for increasing the material hydrophilicity. These results illustrate the potential of Synthetic Microfluidic Paper as a porous microfluidic material with improved performance characteristics, especially for bioassay applications such as diagnostic tests.

Digitally programmable microfluidic automaton for multiscale combinatorial mixing and sample processing†

PubMed Central

Jensen, Erik C.; Stockton, Amanda M.; Chiesl, Thomas N.; Kim, Jungkyu; Bera, Abhisek; Mathies, Richard A.

2013-01-01

A digitally programmable microfluidic Automaton consisting of a 2-dimensional array of pneumatically actuated microvalves is programmed to perform new multiscale mixing and sample processing operations. Large (µL-scale) volume processing operations are enabled by precise metering of multiple reagents within individual nL-scale valves followed by serial repetitive transfer to programmed locations in the array. A novel process exploiting new combining valve concepts is developed for continuous rapid and complete mixing of reagents in less than 800 ms. Mixing, transfer, storage, and rinsing operations are implemented combinatorially to achieve complex assay automation protocols. The practical utility of this technology is demonstrated by performing automated serial dilution for quantitative analysis as well as the first demonstration of on-chip fluorescent derivatization of biomarker targets (carboxylic acids) for microchip capillary electrophoresis on the Mars Organic Analyzer. A language is developed to describe how unit operations are combined to form a microfluidic program. Finally, this technology is used to develop a novel microfluidic 6-sample processor for combinatorial mixing of large sets (>26 unique combinations) of reagents. The digitally programmable microfluidic Automaton is a versatile programmable sample processor for a wide range of process volumes, for multiple samples, and for different types of analyses. PMID:23172232

Microfluidic multiplexing of solid-state nanopores

NASA Astrophysics Data System (ADS)

Jain, Tarun; Rasera, Benjamin C.; Guerrero, Ricardo Jose S.; Lim, Jong-Min; Karnik, Rohit

2017-12-01

Although solid-state nanopores enable electronic analysis of many clinically and biologically relevant molecular structures, there are few existing device architectures that enable high-throughput measurement of solid-state nanopores. Herein, we report a method for microfluidic integration of multiple solid-state nanopores at a high density of one nanopore per (35 µm2). By configuring microfluidic devices with microfluidic valves, the nanopores can be rinsed from a single fluid input while retaining compatibility for multichannel electrical measurements. The microfluidic valves serve the dual purpose of fluidic switching and electric switching, enabling serial multiplexing of the eight nanopores with a single pair of electrodes. Furthermore, the device architecture exhibits low noise and is compatible with electroporation-based in situ nanopore fabrication, providing a scalable platform for automated electronic measurement of a large number of integrated solid-state nanopores.

Multiplex newborn screening for Pompe, Fabry, Hunter, Gaucher, and Hurler diseases using a digital microfluidic platform.

PubMed

Sista, Ramakrishna S; Wang, Tong; Wu, Ning; Graham, Carrie; Eckhardt, Allen; Winger, Theodore; Srinivasan, Vijay; Bali, Deeksha; Millington, David S; Pamula, Vamsee K

2013-09-23

New therapies for lysosomal storage diseases (LSDs) have generated interest in screening newborns for these conditions. We present performance validation data on a digital microfluidic platform that performs multiplex enzymatic assays for Pompe, Fabry, Hunter, Gaucher, and Hurler diseases. We developed an investigational disposable digital microfluidic cartridge that uses a single dried blood spot (DBS) punch for performing a 5-plex fluorometric enzymatic assay on up to 44 DBS samples. Precision and linearity of the assays were determined by analyzing quality control DBS samples; clinical performance was determined by analyzing 600 presumed normal and known affected samples (12 for Pompe, 7 for Fabry and 10 each for Hunter, Gaucher and Hurler). Overall coefficient of variation (CV) values between cartridges, days, instruments, and operators ranged from 2 to 21%; linearity correlation coefficients were ≥0.98 for all assays. The multiplex enzymatic assay performed from a single DBS punch was able to discriminate presumed normal from known affected samples for 5 LSDs. Digital microfluidic technology shows potential for rapid, high-throughput screening for 5 LSDs in a newborn screening laboratory environment. Sample preparation to enzymatic activity on each cartridge is less than 3h. Copyright © 2013 Elsevier B.V. All rights reserved.

Fabrication of microfluidic architectures for optimal flow rate and concentration measurement for lab on chip application

NASA Astrophysics Data System (ADS)

Adam, Tijjani; Hashim, U.

2017-03-01

Optimum flow in micro channel for sensing purpose is challenging. In this study, The optimizations of the fluid sample flows are made through the design and characterization of the novel microfluidics' architectures to achieve the optimal flow rate in the micro channels. The biocompatibility of the Polydimetylsiloxane (Sylgard 184 silicon elastomer) polymer used to fabricate the device offers avenue for the device to be implemented as the universal fluidic delivery system for bio-molecules sensing in various bio-medical applications. The study uses the following methodological approaches, designing a novel microfluidics' architectures by integrating the devices on a single 4 inches silicon substrate, fabricating the designed microfluidic devices using low-cost solution soft lithography technique, characterizing and validating the flow throughput of urine samples in the micro channels by generating pressure gradients through the devices' inlets. The characterization on the urine samples flow in the micro channels have witnessed the constant flow throughout the devices.

Recent developments in microfluidics for cell studies.

PubMed

Xiong, Bin; Ren, Kangning; Shu, Yiwei; Chen, Yin; Shen, Bo; Wu, Hongkai

2014-08-20

As a technique for precisely manipulating fluid at the micrometer scale, the field of microfluidics has experienced an explosive growth over the past two decades, particularly owing to the advances in device design and fabrication. With the inherent advantages associated with its scale of operation, and its flexibility in being incorporated with other microscale techniques for manipulation and detection, microfluidics has become a major enabling technology, which has introduced new paradigms in various fields involving biological cells. A microfluidic device is able to realize functions that are not easily imaginable in conventional biological analysis, such as highly parallel, sophisticated high-throughput analysis, single-cell analysis in a well-defined manner, and tissue engineering with the capability of manipulation at the single-cell level. Major advancements in microfluidic device fabrication and the growing trend of implementing microfluidics in cell studies are presented, with a focus on biological research and clinical diagnostics. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Integrated Microfluidic Devices for Automated Microarray-Based Gene Expression and Genotyping Analysis

NASA Astrophysics Data System (ADS)

Liu, Robin H.; Lodes, Mike; Fuji, H. Sho; Danley, David; McShea, Andrew

Microarray assays typically involve multistage sample processing and fluidic handling, which are generally labor-intensive and time-consuming. Automation of these processes would improve robustness, reduce run-to-run and operator-to-operator variation, and reduce costs. In this chapter, a fully integrated and self-contained microfluidic biochip device that has been developed to automate the fluidic handling steps for microarray-based gene expression or genotyping analysis is presented. The device consists of a semiconductor-based CustomArray® chip with 12,000 features and a microfluidic cartridge. The CustomArray was manufactured using a semiconductor-based in situ synthesis technology. The micro-fluidic cartridge consists of microfluidic pumps, mixers, valves, fluid channels, and reagent storage chambers. Microarray hybridization and subsequent fluidic handling and reactions (including a number of washing and labeling steps) were performed in this fully automated and miniature device before fluorescent image scanning of the microarray chip. Electrochemical micropumps were integrated in the cartridge to provide pumping of liquid solutions. A micromixing technique based on gas bubbling generated by electrochemical micropumps was developed. Low-cost check valves were implemented in the cartridge to prevent cross-talk of the stored reagents. Gene expression study of the human leukemia cell line (K562) and genotyping detection and sequencing of influenza A subtypes have been demonstrated using this integrated biochip platform. For gene expression assays, the microfluidic CustomArray device detected sample RNAs with a concentration as low as 0.375 pM. Detection was quantitative over more than three orders of magnitude. Experiment also showed that chip-to-chip variability was low indicating that the integrated microfluidic devices eliminate manual fluidic handling steps that can be a significant source of variability in genomic analysis. The genotyping results showed that the device identified influenza A hemagglutinin and neuraminidase subtypes and sequenced portions of both genes, demonstrating the potential of integrated microfluidic and microarray technology for multiple virus detection. The device provides a cost-effective solution to eliminate labor-intensive and time-consuming fluidic handling steps and allows microarray-based DNA analysis in a rapid and automated fashion.

Microfluidic opportunities in the field of nutrition

PubMed Central

Li, Sixing; Kiehne, Justin; Sinoway, Lawrence I.; Cameron, Craig E.

2013-01-01

Nutrition has always been closely related to human health, which is a constant motivational force driving research in a variety of disciplines. Over the years, the rapidly emerging field of microfluidics has been pushing forward the healthcare industry with the development of microfluidic-based, point-of-care (POC) diagnostic devices. Though a great deal of work has been done in developing microfluidic platforms for disease diagnoses, potential microfluidic applications in the field of nutrition remain largely unexplored. In this Focus article, we would like to investigate the potential chances for microfluidics in the field of nutrition. We will first highlight some of the recent advances in microfluidic blood analysis systems that have the capacity to detect biomarkers of nutrition. Then we will examine existing examples of microfluidic devices for the detection of specific biomarkers of nutrition or nutrient content in food. Finally, we will discuss the challenges in this field and provide some insight into the future of applied microfluidics in nutrition. PMID:24056522

Principles, Techniques, and Applications of Tissue Microfluidics

NASA Technical Reports Server (NTRS)

Wade, Lawrence A.; Kartalov, Emil P.; Shibata, Darryl; Taylor, Clive

2011-01-01

The principle of tissue microfluidics and its resultant techniques has been applied to cell analysis. Building microfluidics to suit a particular tissue sample would allow the rapid, reliable, inexpensive, highly parallelized, selective extraction of chosen regions of tissue for purposes of further biochemical analysis. Furthermore, the applicability of the techniques ranges beyond the described pathology application. For example, they would also allow the posing and successful answering of new sets of questions in many areas of fundamental research. The proposed integration of microfluidic techniques and tissue slice samples is called "tissue microfluidics" because it molds the microfluidic architectures in accordance with each particular structure of each specific tissue sample. Thus, microfluidics can be built around the tissues, following the tissue structure, or alternatively, the microfluidics can be adapted to the specific geometry of particular tissues. By contrast, the traditional approach is that microfluidic devices are structured in accordance with engineering considerations, while the biological components in applied devices are forced to comply with these engineering presets.

Optofluidic platforms based on surface-enhanced Raman scattering.

PubMed

Lim, Chaesung; Hong, Jongin; Chung, Bong Geun; deMello, Andrew J; Choo, Jaebum

2010-05-01

We report recent progress in the development of surface-enhanced Raman scattering (SERS)-based optofluidic platforms for the fast and sensitive detection of chemical and biological analytes. In the current context, a SERS-based optofluidic platform is defined as an integrated analytical device composed of a microfluidic element and a sensitive Raman spectrometer. Optofluidic devices for SERS detection normally involve nanocolloid-based microfluidic systems or metal nanostructure-embedded microfluidic systems. In the current review, recent advances in both approaches are surveyed and assessed. Additionally, integrated real-time sensing systems that combine portable Raman spectrometers with microfluidic devices are also reviewed. Such real-time sensing systems have significant utility in environmental monitoring, forensic science and homeland defense applications.

Microfluidic devices for the controlled manipulation of small volumes

DOEpatents

Ramsey, Michael J; Jacobson, Stephen C

2012-09-18

A method for conducting a broad range of biochemical analyses or manipulations on a series of nano- to subnanoliter reaction volumes and an apparatus for carrying out the same are disclosed. The invention is implemented on a fluidic microchip to provide high serial throughput. In particular, the disclosed device is a microfabricated channel device that can manipulate nanoliter or subnanoliter reaction volumes in a controlled manner to produce results at rates of 1 to 10 Hz per channel. The reaction volumes are manipulated in serial fashion analogous to a digital shift register. The invention has application to such problems as screening molecular or cellular targets using single beads from split-synthesis combinatorial libraries, screening single cells for RNA or protein expression, genetic diagnostic screening at the single cell level, or performing single cell signal transduction studies.

Microfluidic devices for the controlled manipulation of small volumes

DOEpatents

Ramsey, J Michael [Knoxville, TN; Jacobson, Stephen C [Knoxville, TN

2007-07-03

A method for conducting a broad range of biochemical analyses or manipulations on a series of nano- to subnanoliter reaction volumes and an apparatus for carrying out the same are disclosed. The invention is implemented on a fluidic microchip to provide high serial throughput. In particular, the disclosed device is a microfabricated channel device that can manipulate nanoliter or subnanoliter reaction volumes in a controlled manner to produce results at rates of 1 to 10 Hz per channel. The reaction volumes are manipulated in serial fashion analogous to a digital shift register. The invention has application to such problems as screening molecular or cellular targets using single beads from split-synthesis combinatorial libraries, screening single cells for RNA or protein expression, genetic diagnostic screening at the single cell level, or performing single cell signal transduction studies.

Selective Distance-Based K+ Quantification on Paper-Based Microfluidics.

PubMed

Gerold, Chase T; Bakker, Eric; Henry, Charles S

2018-04-03

In this study, paper-based microfluidic devices (μPADs) capable of K + quantification in aqueous samples, as well as in human serum, using both colorimetric and distance-based methods are described. A lipophilic phase containing potassium ionophore I (valinomycin) was utilized to achieve highly selective quantification of K + in the presence of Na + , Li + , and Mg 2+ ions. Successful addition of a suspended lipophilic phase to a wax printed paper-based device is described and offers a solution to current approaches that rely on organic solvents, which damage wax barriers. The approach provides an avenue for future alkali/alkaline quantification utilizing μPADs. Colorimetric spot tests allowed for K + quantification from 0.1-5.0 mM using only 3.00 μL of sample solution. Selective distance-based quantification required small sample volumes (6.00 μL) and gave responses sensitive enough to distinguish between 1.0 and 2.5 mM of sample K + . μPADs using distance-based methods were also capable of differentiating between 4.3 and 6.9 mM K + in human serum samples. Distance-based methods required no digital analysis, electronic hardware, or pumps; any steps required for quantification could be carried out using the naked eye.

Microfluidic Device

NASA Technical Reports Server (NTRS)

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

2016-01-01

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

Microfluidic Device

NASA Technical Reports Server (NTRS)

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

2015-01-01

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

Microfluidic Device

NASA Technical Reports Server (NTRS)

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

2017-01-01

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

Flexible microfluidic devices with three-dimensional interconnected microporous walls for gas and liquid applications.

PubMed

Yuen, Po Ki; DeRosa, Michael E

2011-10-07

This article presents a simple, low-cost method of fabrication and the applications of flexible polystyrene microfluidic devices with three-dimensional (3D) interconnected microporous walls based on treatment using a solvent/non-solvent mixture at room temperature. The complete fabrication process from device design concept to working device can be completed in less than an hour in a regular laboratory setting, without the need for expensive equipment. Microfluidic devices were used to demonstrate gas generation and absorption reactions by acidifying water with carbon dioxide (CO(2)) gas. By selectively treating the microporous structures with oxygen plasma, acidification of water by acetic acid (distilled white vinegar) perfusion was also demonstrated with the same device design.

Multivariate Analysis To Quantify Species in the Presence of Direct Interferents: Micro-Raman Analysis of HNO 3 in Microfluidic Devices

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lines, Amanda M.; Nelson, Gilbert L.; Casella, Amanda J.

Microfluidic devices are a growing field with significant potential for application to small scale processing of solutions. Much like large scale processing, fast, reliable, and cost effective means of monitoring the streams during processing are needed. Here we apply a novel Micro-Raman probe to the on-line monitoring of streams within a microfluidic device. For either macro or micro scale process monitoring via spectroscopic response, there is the danger of interfering or confounded bands obfuscating results. By utilizing chemometric analysis, a form of multivariate analysis, species can be accurately quantified in solution despite the presence of overlapping or confounded spectroscopic bands.more » This is demonstrated on solutions of HNO 3 and NaNO 3 within micro-flow and microfluidic devices.« less

An integrated optics microfluidic device for detecting single DNA molecules.

PubMed

Krogmeier, Jeffrey R; Schaefer, Ian; Seward, George; Yantz, Gregory R; Larson, Jonathan W

2007-12-01

A fluorescence-based integrated optics microfluidic device is presented, capable of detecting single DNA molecules in a high throughput and reproducible manner. The device integrates microfluidics for DNA stretching with two optical elements for single molecule detection (SMD): a plano-aspheric refractive lens for fluorescence excitation (illuminator) and a solid parabolic reflective mirror for fluorescence collection (collector). Although miniaturized in size, both optical components were produced and assembled onto the microfluidic device by readily manufacturable fabrication techniques. The optical resolution of the device is determined by the small and relatively low numerical aperture (NA) illuminator lens (0.10 effective NA, 4.0 mm diameter) that delivers excitation light to a diffraction limited 2.0 microm diameter spot at full width half maximum within the microfluidic channel. The collector (0.82 annular NA, 15 mm diameter) reflects the fluorescence over a large collection angle, representing 71% of a hemisphere, toward a single photon counting module in an infinity-corrected scheme. As a proof-of-principle experiment for this simple integrated device, individual intercalated lambda-phage DNA molecules (48.5 kb) were stretched in a mixed elongational-shear microflow, detected, and sized with a fluorescence signal to noise ratio of 9.9 +/-1.0. We have demonstrated that SMD does not require traditional high numerical aperture objective lenses and sub-micron positioning systems conventionally used in many applications. Rather, standard manufacturing processes can be combined in a novel way that promises greater accessibility and affordability for microfluidic-based single molecule applications.

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.

Microfluidics and photonics for Bio-System-on-a-Chip: a review of advancements in technology towards a microfluidic flow cytometry chip.

PubMed

Godin, Jessica; Chen, Chun-Hao; Cho, Sung Hwan; Qiao, Wen; Tsai, Frank; Lo, Yu-Hwa

2008-10-01

Microfluidics and photonics come together to form a field commonly referred to as 'optofluidics'. Flow cytometry provides the field with a technology base from which both microfluidic and photonic components be developed and integrated into a useful device. This article reviews some of the more recent developments to familiarize a reader with the current state of the technologies and also highlights the requirements of the device and how researchers are working to meet these needs.

Inexpensive, rapid prototyping of microfluidic devices using overhead transparencies and a laser print, cut and laminate fabrication method.

PubMed

Thompson, Brandon L; Ouyang, Yiwen; Duarte, Gabriela R M; Carrilho, Emanuel; Krauss, Shannon T; Landers, James P

2015-06-01

We describe a technique for fabricating microfluidic devices with complex multilayer architectures using a laser printer, a CO2 laser cutter, an office laminator and common overhead transparencies as a printable substrate via a laser print, cut and laminate (PCL) methodology. The printer toner serves three functions: (i) it defines the microfluidic architecture, which is printed on the overhead transparencies; (ii) it acts as the adhesive agent for the bonding of multiple transparency layers; and (iii) it provides, in its unmodified state, printable, hydrophobic 'valves' for fluidic flow control. By using common graphics software, e.g., CorelDRAW or AutoCAD, the protocol produces microfluidic devices with a design-to-device time of ∼40 min. Devices of any shape can be generated for an array of multistep assays, with colorimetric detection of molecular species ranging from small molecules to proteins. Channels with varying depths can be formed using multiple transparency layers in which a CO2 laser is used to remove the polyester from the channel sections of the internal layers. The simplicity of the protocol, availability of the equipment and substrate and cost-effective nature of the process make microfluidic devices available to those who might benefit most from expedited, microscale chemistry.

Microfabrication of plastic-PDMS microfluidic devices using polyimide release layer and selective adhesive bonding

DOE PAGES

Wang, Shuyu; Yu, Shifeng; Lu, Ming; ...

2017-03-15

In this study, we present an improved method to bond poly(dimethylsiloxane) (PDMS) with polyimide (PI) to develop flexible substrate microfluidic devices. The PI film was separately fabricated on a silicon wafer by spin coating followed by thermal treatment to avoid surface unevenness of the flexible substrate. In this way, we could also integrate flexible substrate into standard micro-electromechanical systems (MEMS) fabrication. Meanwhile, the adhesive epoxy was selectively transferred to the PDMS microfluidic device by a stamp-and-stick method to avoid epoxy clogging the microfluidic channels. To spread out the epoxy evenly on the transferring substrate, we used superhydrophilic vanadium oxide filmmore » coated glass as the transferring substrate. After the bonding process, the flexible substrate could easily be peeled off from the rigid substrate. Contact angle measurement was used to characterize the hydrophicity of the vanadium oxide film. X-ray photoelectron spectroscopy analysis was conducted to study the surface of the epoxy. We further evaluated the bonding quality by peeling tests, which showed a maximum bonding strength of 100 kPa. By injecting with black ink, the plastic microfluidic device was confirmed to be well bonded with no leakage for a day under 1 atm. Finally, this proposed versatile method could bond the microfluidic device and plastic substrate together and be applied in the fabrication of some biosensors and lab-on-a-chip systems.« less

Microfabrication of plastic-PDMS microfluidic devices using polyimide release layer and selective adhesive bonding

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Shuyu; Yu, Shifeng; Lu, Ming

In this study, we present an improved method to bond poly(dimethylsiloxane) (PDMS) with polyimide (PI) to develop flexible substrate microfluidic devices. The PI film was separately fabricated on a silicon wafer by spin coating followed by thermal treatment to avoid surface unevenness of the flexible substrate. In this way, we could also integrate flexible substrate into standard micro-electromechanical systems (MEMS) fabrication. Meanwhile, the adhesive epoxy was selectively transferred to the PDMS microfluidic device by a stamp-and-stick method to avoid epoxy clogging the microfluidic channels. To spread out the epoxy evenly on the transferring substrate, we used superhydrophilic vanadium oxide filmmore » coated glass as the transferring substrate. After the bonding process, the flexible substrate could easily be peeled off from the rigid substrate. Contact angle measurement was used to characterize the hydrophicity of the vanadium oxide film. X-ray photoelectron spectroscopy analysis was conducted to study the surface of the epoxy. We further evaluated the bonding quality by peeling tests, which showed a maximum bonding strength of 100 kPa. By injecting with black ink, the plastic microfluidic device was confirmed to be well bonded with no leakage for a day under 1 atm. Finally, this proposed versatile method could bond the microfluidic device and plastic substrate together and be applied in the fabrication of some biosensors and lab-on-a-chip systems.« less

Microfluidic sieve valves

DOE Office of Scientific and Technical Information (OSTI.GOV)

Quake, Stephen R; Marcus, Joshua S; Hansen, Carl L

2015-01-13

Sieve valves for use in microfluidic device are provided. The valves are useful for impeding the flow of particles, such as chromatography beads or cells, in a microfluidic channel while allowing liquid solution to pass through the valve. The valves find particular use in making microfluidic chromatography modules.

Integrated high pressure manifold for thermoplastic microfluidic devices

NASA Astrophysics Data System (ADS)

Aghvami, S. Ali; Fraden, Seth

2017-11-01

We introduce an integrated tubing manifold for thermoplastic microfluidic chips that tolerates high pressure. In contrast to easy tubing in PDMS microfluidic devices, tube connection has been challenging for plastic microfluidics. Our integrated manifold connection tolerates 360 psi while conventional PDMS connections fail at 50 psi. Important design considerations are incorporation of a quick-connect, leak-free and high-pressure manifold for the inlets and outlets on the lid and registration marks that allow the precise alignment of the inlets and outlets. In our method, devices are comprised of two molded pieces joined together to create a sealed device. The first piece contains the microfluidic features and the second contains the inlet and outlet manifold, a frame for rigidity and a viewing window. The mold for the lid with integrated manifold is CNC milled from aluminium. A cone shape PDMS component which acts as an O-ring, seals the connection between molded manifold and tubing. The lid piece with integrated inlet and outlets will be a standard piece and can be used for different chips and designs. Sealing the thermoplastic device is accomplished by timed immersion of the lid in a mixture of volatile and non-volatile solvents followed by application of heat and pressure.

Low cost microfluidic device based on cotton threads for electroanalytical application.

PubMed

Agustini, Deonir; Bergamini, Márcio F; Marcolino-Junior, Luiz Humberto

2016-01-21

Microfluidic devices are an interesting alternative for performing analytical assays, due to the speed of analyses, reduced sample, reagent and solvent consumption and less waste generation. However, the high manufacturing costs still prevent the massive use of these devices worldwide. Here, we present the construction of a low cost microfluidic thread-based electroanalytical device (μTED), employing extremely cheap materials and a manufacturing process free of equipment. The microfluidic channels were built with cotton threads and the estimated cost per device was only $0.39. The flow of solutions (1.12 μL s(-1)) is generated spontaneously due to the capillary forces, eliminating the use of any pumping system. To demonstrate the analytical performance of the μTED, a simultaneous determination of acetaminophen (ACT) and diclofenac (DCF) was performed by multiple pulse amperometry (MPA). A linear dynamic range (LDR) of 10 to 320 μmol L(-1) for both species, a limit of detection (LOD) and a limit of quantitation (LOQ) of 1.4 and 4.7 μmol L(-1) and 2.5 and 8.3 μmol L(-1) for ACT and DCF, respectively, as well as an analytical frequency of 45 injections per hour were reached. Thus, the proposed device has shown potential to extend the use of microfluidic analytical devices, due to its simplicity, low cost and good analytical performance.

Microfluidic Devices for Drug Delivery Systems and Drug Screening

PubMed Central

Kompella, Uday B.; Damiati, Safa A.

2018-01-01

Microfluidic devices present unique advantages for the development of efficient drug carrier particles, cell-free protein synthesis systems, and rapid techniques for direct drug screening. Compared to bulk methods, by efficiently controlling the geometries of the fabricated chip and the flow rates of multiphase fluids, microfluidic technology enables the generation of highly stable, uniform, monodispersed particles with higher encapsulation efficiency. Since the existing preclinical models are inefficient drug screens for predicting clinical outcomes, microfluidic platforms might offer a more rapid and cost-effective alternative. Compared to 2D cell culture systems and in vivo animal models, microfluidic 3D platforms mimic the in vivo cell systems in a simple, inexpensive manner, which allows high throughput and multiplexed drug screening at the cell, organ, and whole-body levels. In this review, the generation of appropriate drug or gene carriers including different particle types using different configurations of microfluidic devices is highlighted. Additionally, this paper discusses the emergence of fabricated microfluidic cell-free protein synthesis systems for potential use at point of care as well as cell-, organ-, and human-on-a-chip models as smart, sensitive, and reproducible platforms, allowing the investigation of the effects of drugs under conditions imitating the biological system. PMID:29462948

Effects of surface properties on droplet formation inside a microfluidic device

NASA Astrophysics Data System (ADS)

Steinhaus, Ben; Shen, Amy

2004-11-01

Micro-fluidic devices offer a unique method of creating and controlling droplets on small length scales. A microfluidic device is used to study the effects of surface properties on droplet formation of a 2-phase flow system. Four phase diagrams are generated to compare the dynamics of the 2 immiscible fluid system (silicone oil and water) inside microchannels with different surface properties. Results show that the channel surface plays an important role in determining the flow patterns and the droplet formation of the 2-phase fluid system.

"Off-the-shelf" 3-D microfluidic nozzle.

PubMed

Terray, Alex; Hart, Sean J

2010-07-07

We present the construction and operation of a microfluidic nozzle created using several standard fluidic parts available commercially. By elegantly combining several pieces from a standard assembly, a capillary and a few other standard parts, we were able to develop a novel device. Using this device, precise axisymmetric flow focusing of particles was achieved and observed at the exit of the nozzle and within a connected microfluidic device several centimetres away. Sheath and core flow rates were varied to show influence and control over the width of the focused particles.

Packaging of electro-microfluidic devices

DOEpatents

Benavides, Gilbert L.; Galambos, Paul C.; Emerson, John A.; Peterson, Kenneth A.; Giunta, Rachel K.; Zamora, David Lee; Watson, Robert D.

2003-04-15

A new architecture for packaging surface micromachined electro-microfluidic devices is presented. This architecture relies on two scales of packaging to bring fluid to the device scale (picoliters) from the macro-scale (microliters). The architecture emulates and utilizes electronics packaging technology. The larger package consists of a circuit board with embedded fluidic channels and standard fluidic connectors (e.g. Fluidic Printed Wiring Board). The embedded channels connect to the smaller package, an Electro-Microfluidic Dual-Inline-Package (EMDIP) that takes fluid to the microfluidic integrated circuit (MIC). The fluidic connection is made to the back of the MIC through Bosch-etched holes that take fluid to surface micromachined channels on the front of the MIC. Electrical connection is made to bond pads on the front of the MIC.

Packaging of electro-microfluidic devices

DOEpatents

Benavides, Gilbert L.; Galambos, Paul C.; Emerson, John A.; Peterson, Kenneth A.; Giunta, Rachel K.; Watson, Robert D.

2002-01-01

A new architecture for packaging surface micromachined electro-microfluidic devices is presented. This architecture relies on two scales of packaging to bring fluid to the device scale (picoliters) from the macro-scale (microliters). The architecture emulates and utilizes electronics packaging technology. The larger package consists of a circuit board with embedded fluidic channels and standard fluidic connectors (e.g. Fluidic Printed Wiring Board). The embedded channels connect to the smaller package, an Electro-Microfluidic Dual-Inline-Package (EMDIP) that takes fluid to the microfluidic integrated circuit (MIC). The fluidic connection is made to the back of the MIC through Bosch-etched holes that take fluid to surface micromachined channels on the front of the MIC. Electrical connection is made to bond pads on the front of the MIC.

Microfluidic Mixing: A Review

PubMed Central

Lee, Chia-Yen; Chang, Chin-Lung; Wang, Yao-Nan; Fu, Lung-Ming

2011-01-01

The aim of microfluidic mixing is to achieve a thorough and rapid mixing of multiple samples in microscale devices. In such devices, sample mixing is essentially achieved by enhancing the diffusion effect between the different species flows. Broadly speaking, microfluidic mixing schemes can be categorized as either “active”, where an external energy force is applied to perturb the sample species, or “passive”, where the contact area and contact time of the species samples are increased through specially-designed microchannel configurations. Many mixers have been proposed to facilitate this task over the past 10 years. Accordingly, this paper commences by providing a high level overview of the field of microfluidic mixing devices before describing some of the more significant proposals for active and passive mixers. PMID:21686184

Digital PCR on an integrated self-priming compartmentalization chip.

PubMed

Zhu, Qiangyuan; Qiu, Lin; Yu, Bingwen; Xu, Yanan; Gao, Yibo; Pan, Tingting; Tian, Qingchang; Song, Qi; Jin, Wei; Jin, Qinhan; Mu, Ying

2014-03-21

An integrated on-chip valve-free and power-free microfluidic digital PCR device is for the first time developed by making use of a novel self-priming compartmentalization and simple dehydration control to realize 'divide and conquer' for single DNA molecule detection. The high gas solubility of PDMS is exploited to provide the built-in power of self-priming so that the sample and oil are sequentially sucked into the device to realize sample self-compartmentalization based on surface tension. The lifespan of its self-priming capability was about two weeks tested using an air-tight packaging bottle sealed with a small amount of petroleum jelly, which is significant for a practical platform. The SPC chip contains 5120 independent 5 nL microchambers, allowing the samples to be compartmentalized completely. Using this platform, three different abundances of lung cancer related genes are detected to demonstrate the feasibility and flexibility of the microchip for amplifying a single nucleic acid molecule. For maximal accuracy, within less than 5% of the measurement deviation, the optimal number of positive chambers is between 400 and 1250 evaluated by the Poisson distribution, which means one panel can detect an average of 480 to 4804 template molecules. This device without world-to-chip connections eliminates the constraint of the complex pipeline control, and is an integrated on-chip platform, which would be a significant improvement to digital PCR automation and more user-friendly.

Design of pressure-driven microfluidic networks using electric circuit analogy.

PubMed

Oh, Kwang W; Lee, Kangsun; Ahn, Byungwook; Furlani, Edward P

2012-02-07

This article reviews the application of electric circuit methods for the analysis of pressure-driven microfluidic networks with an emphasis on concentration- and flow-dependent systems. The application of circuit methods to microfluidics is based on the analogous behaviour of hydraulic and electric circuits with correlations of pressure to voltage, volumetric flow rate to current, and hydraulic to electric resistance. Circuit analysis enables rapid predictions of pressure-driven laminar flow in microchannels and is very useful for designing complex microfluidic networks in advance of fabrication. This article provides a comprehensive overview of the physics of pressure-driven laminar flow, the formal analogy between electric and hydraulic circuits, applications of circuit theory to microfluidic network-based devices, recent development and applications of concentration- and flow-dependent microfluidic networks, and promising future applications. The lab-on-a-chip (LOC) and microfluidics community will gain insightful ideas and practical design strategies for developing unique microfluidic network-based devices to address a broad range of biological, chemical, pharmaceutical, and other scientific and technical challenges.

Single step sequential polydimethylsiloxane wet etching to fabricate a microfluidic channel with various cross-sectional geometries

NASA Astrophysics Data System (ADS)

Wang, C.-K.; Liao, W.-H.; Wu, H.-M.; Lo, Y.-H.; Lin, T.-R.; Tung, Y.-C.

2017-11-01

Polydimethylsiloxane (PDMS) has become a widely used material to construct microfluidic devices for various biomedical and chemical applications due to its desirable material properties and manufacturability. PDMS microfluidic devices are usually fabricated using soft lithography replica molding methods with master molds made of photolithogrpahy patterned photoresist layers on silicon wafers. The fabricated microfluidic channels often have rectangular cross-sectional geometries with single or multiple heights. In this paper, we develop a single step sequential PDMS wet etching process that can be used to fabricate microfluidic channels with various cross-sectional geometries from single-layer PDMS microfluidic channels. The cross-sections of the fabricated channel can be non-rectangular, and varied along the flow direction. Furthermore, the fabricated cross-sectional geometries can be numerically simulated beforehand. In the experiments, we fabricate microfluidic channels with various cross-sectional geometries using the developed technique. In addition, we fabricate a microfluidic mixer with alternative mirrored cross-sectional geometries along the flow direction to demonstrate the practical usage of the developed technique.

Electrokinetic focusing injection methods on microfluidic devices.

PubMed

Fu, Lung-Ming; Yang, Ruey-Jen; Lee, Gwo-Bin

2003-04-15

This paper presents an experimental and numerical investigation into electrokinetic focusing injection on microfluidic chips. The valving characteristics on microfluidic devices are controlled through appropriate manipulations of the electric potential strengths during the sample loading and dispensing steps. The present study also addresses the design and testing of various injection systems used to deliver a sample plug. A novel double-cross injection microfluidic chip is fabricated, which employs electrokinetic focusing to deliver sample plugs of variable volume. The proposed design combines several functions of traditional sample plug injection systems on a single microfluidic chip. The injection technique uses an unique sequence of loading steps with different electric potential distributions and magnitudes within the various channels to effectuate a virtual valve.

On-demand generation and mixing of liquid-in-gas slugs with digitally-programmable composition and size

PubMed Central

Chen, Yi-Chun; Liu, Kan; Shen, Clifton Kwang-Fu; van Dam, R. Michael

2017-01-01

Microscopic droplets or slugs of mixed reagents provide a convenient platform for performing large numbers of isolated biochemical or chemical reactions for many screening and optimization applications. Myriad microfluidic approaches have emerged for creating droplets or slugs with controllable size and composition, generally using an immiscible carrier fluid to assist with the formation or merging processes. We report a novel device for generation of liquid slugs in air when the use of a carrier liquid is not compatible with the application. The slug generator contains two adjacent chambers, each of which has a volume that can be digitally adjusted by closing selected microvalves. Reagents are filled into the two chambers, merged together into a contiguous liquid slug, ejected at the desired time from the device using gas pressure, and mixed by flowing in a downstream channel. Programmable size and composition of slugs is achieved by dynamically adjusting the volume of each chamber prior to filling. Slug formation in this fashion is independent of fluid properties and can easily be scaled to mix larger numbers of reagents. This device has already been used to screen monomer ratios in supramolecular nanoparticle assembly and radiolabeling conditions of engineered antibodies, and here we provide a detailed description of the underlying device. PMID:29167603

ZnO-Based Microfluidic pH Sensor: A Versatile Approach for Quick Recognition of Circulating Tumor Cells in Blood.

PubMed

Mani, Ganesh Kumar; Morohoshi, Madoka; Yasoda, Yutaka; Yokoyama, Sho; Kimura, Hiroshi; Tsuchiya, Kazuyoshi

2017-02-15

The present study is concerned about the development of highly sensitive and stable microfluidic pH sensor for possible identification of circulating tumor cells (CTCs) in blood. The precise pH measurements between silver-silver chloride (Ag/AgCl) reference electrode and zinc oxide (ZnO) working electrode have been investigated in the microfluidic device. Since there is a direct link between pH and cancer cells, the developed device is one of the valuable tools to examine circulating tumor cells (CTCs) in blood. The ZnO-based working electrode was deposited by radio frequency (rf) sputtering technique. The potential voltage difference between the working and reference electrodes (Ag/AgCl) is evaluated on the microfluidic device. The ideal Nernstian response of -43.71165 mV/pH was achieved along with high stability and quick response time. Finally, to evaluate the real time capability of the developed microfluidic device, in vitro testing was done with A549, A7r5, and MDCK cells.

Integrated single-walled carbon nanotube/microfluidic devices for the study of the sensing mechanism of nanotube sensors.

PubMed

Fu, Qiang; Liu, Jie

2005-07-21

A method to fabricate integrated single-walled carbon nanotube/microfluidic devices was developed. This simple process could be used to directly prepare nanotube thin film transistors within the microfluidic channel and to register SWNT devices with the microfludic channel without the need of an additional alignment step. The microfluidic device was designed to have several inlets that deliver multiple liquid flows to a single main channel. The location and width of each flow in the main channel could be controlled by the relative flow rates. This capability enabled us to study the effect of the location and the coverage area of the liquid flow that contained charged molecules on the conduction of the nanotube devices, providing important information on the sensing mechanism of carbon nanotube sensors. The results showed that in a sensor based on a nanotube thin film field effect transistor, the sensing signal came from target molecules absorbed on or around the nanotubes. The effect from adsorption on metal electrodes was weak.

Transfection in perfused microfluidic cell culture devices: A case study.

PubMed

Raimes, William; Rubi, Mathieu; Super, Alexandre; Marques, Marco P C; Veraitch, Farlan; Szita, Nicolas

2017-08-01

Automated microfluidic devices are a promising route towards a point-of-care autologous cell therapy. The initial steps of induced pluripotent stem cell (iPSC) derivation involve transfection and long term cell culture. Integration of these steps would help reduce the cost and footprint of micro-scale devices with applications in cell reprogramming or gene correction. Current examples of transfection integration focus on maximising efficiency rather than viable long-term culture. Here we look for whole process compatibility by integrating automated transfection with a perfused microfluidic device designed for homogeneous culture conditions. The injection process was characterised using fluorescein to establish a LabVIEW-based routine for user-defined automation. Proof-of-concept is demonstrated by chemically transfecting a GFP plasmid into mouse embryonic stem cells (mESCs). Cells transfected in the device showed an improvement in efficiency (34%, n = 3) compared with standard protocols (17.2%, n = 3). This represents a first step towards microfluidic processing systems for cell reprogramming or gene therapy.

Implementation of poly(ε-caprolactone) sheet-based shape-memory polymer microvalves into plastic-based microfluidic devices

NASA Astrophysics Data System (ADS)

Jiang, Chenyang; Uto, Koichiro; Ebara, Mitsuhiro; Aoyagi, Takao; Ichiki, Takanori

2015-06-01

Implementation of shape-memory polymer (SMP) sheet-based microvalves into plastic-based microfluidic devices has been studied toward the use in disposable and mass producible micro total analysis devices. Poly(ε-caprolactone) (PCL) and poly(methyl methacrylate-co-styrene) (MS) were used as SMP and main substrate materials, respectively. Bonding between PCL sheets and MS plates was the critical issue in the practical implementation. We found the pristine PCL sheet has relatively rough surface with Ra of 85.14 nm, which is the cause of poor bonding. Hence, by introducing the post-anneal treatment with sandwiched between two flat glass plates, the PCL surface could be smoothed to Ra of 12.50 nm, and tight bonding could be obtained. Consequently, microfluidic devices consisting of plastic/PCL/plastic layers were successfully fabricated and therein the actuation of SMP valves without any leakage was demonstrated. The present technology is expected to be applicable to disposable microfluidic devices as required for point-of-care testing.

Microfluidic devices with permeable polymer barriers for capture and transport of biomolecules and cells.

PubMed

Lee, Ho Suk; Chu, Wai Keung; Zhang, Kun; Huang, Xiaohua

2013-09-07

We report a method for fabricating permeable polymer microstructure barriers in polydimethylsiloxane (PDMS) microfluidic devices and the use of the devices to capture and transport DNA and cells. The polymer microstructure in a desired location in a fluidic channel is formed in situ by the polymerization of acrylamide and polyethylene diacrylate cross-linker (PEG-DA) monomer in a solution which is trapped in the location using a pair of PDMS valves. The porous polymer microstructure provides a mechanical barrier to convective fluid flow in the channel or between two microfluidic chambers while it still conducts ions or small charged species under an electric field, allowing for the rapid capture and transport of biomolecules and cells by electrophoresis. We have demonstrated the application of the devices for the rapid capture and efficient release of bacteriophage λ genomic DNA, solution exchange and for the transport and capture of HeLa cells. Our devices will enable the multi-step processing of biomolecules and cells or individual cells within a single microfluidic chamber.

Desktop-Stereolithography 3D-Printing of a Poly(dimethylsiloxane)-Based Material with Sylgard-184 Properties.

PubMed

Bhattacharjee, Nirveek; Parra-Cabrera, Cesar; Kim, Yong Tae; Kuo, Alexandra P; Folch, Albert

2018-05-01

The advantageous physiochemical properties of poly(dimethylsiloxane) (PDMS) have made it an extremely useful material for prototyping in various technological, scientific, and clinical areas. However, PDMS molding is a manual procedure and requires tedious assembly steps, especially for 3D designs, thereby limiting its access and usability. On the other hand, automated digital manufacturing processes such as stereolithography (SL) enable true 3D design and fabrication. Here the formulation, characterization, and SL application of a 3D-printable PDMS resin (3DP-PDMS) based on commercially available PDMS-methacrylate macromers, a high-efficiency photoinitiator and a high-absorbance photosensitizer, is reported. Using a desktop SL-printer, optically transparent submillimeter structures and microfluidic channels are demonstrated. An optimized blend of PDMS-methacrylate macromers is also used to SL-print structures with mechanical properties similar to conventional thermally cured PDMS (Sylgard-184). Furthermore, it is shown that SL-printed 3DP-PDMS substrates can be rendered suitable for mammalian cell culture. The 3DP-PDMS resin enables assembly-free, automated, digital manufacturing of PDMS, which should facilitate the prototyping of devices for microfluidics, organ-on-chip platforms, soft robotics, flexible electronics, and sensors, among others. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Interferometric characterization of pyroelectrically activated micro-arrays of liquid lenses in lithium niobate crystals

NASA Astrophysics Data System (ADS)

Grilli, S.; Miccio, L.; Vespini, V.; Ferraro, P.

2008-08-01

In recent years a wide variety of liquid based optical elements have been conceived, designed and fabricated even for commercial products like digital cameras. The impressive development of microfluidic systems in conjunction with optics has led to the creation of a completely new field of investigation named optofludics. Among other things, the optofluidic area deals with the investigation and the realization of liquid micro-lenses. Different methods and configurations have been proposed in literature to achieve liquid variable micro-lenses. This paper reports about the possibility to achieve lensing effect by a relatively easy to accomplish technique based on an open microfluidic system consisting of a tiny amount of appropriate liquid manipulated by the pyroelectric effect onto a periodically poled LiNbO3 substrate. Basically, an electrowetting process is performed to actuate the liquid film by using the surface charges generated pyroelectrically under temperature variation. The configuration is electrode-less compared to standard electrowetting systems, thus improving the device flexibility and easiness of fabrication. The curvature of the liquid lenses has been characterized by interferometric techniques based on the evaluation of the phase map through digital holography. The results showing the evolution of the lens curvature with the temperature variation will be presented and discussed.

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

PubMed Central

Alvankarian, Jafar; Majlis, Burhanuddin Yeop

2015-01-01

The adjustable microfluidic devices that have been developed for hydrodynamic-based fractionation of beads and cells are important for fast performance tunability through interaction of mechanical properties of particles in fluid flow and mechanically flexible microstructures. In this review, the research works reported on fabrication and testing of the tunable elastomeric microfluidic devices for applications such as separation, filtration, isolation, and trapping of single or bulk of microbeads or cells are discussed. Such microfluidic systems for rapid performance alteration are classified in two groups of bulk deformation of microdevices using external mechanical forces, and local deformation of microstructures using flexible membrane by pneumatic pressure. The main advantage of membrane-based tunable systems has been addressed to be the high capability of integration with other microdevice components. The stretchable devices based on bulk deformation of microstructures have in common advantage of simplicity in design and fabrication process. PMID:26610519

Micro Electromechanical Systems (MEMS) Based Microfluidic Devices for Biomedical Applications

PubMed Central

Ashraf, Muhammad Waseem; Tayyaba, Shahzadi; Afzulpurkar, Nitin

2011-01-01

Micro Electromechanical Systems (MEMS) based microfluidic devices have gained popularity in biomedicine field over the last few years. In this paper, a comprehensive overview of microfluidic devices such as micropumps and microneedles has been presented for biomedical applications. The aim of this paper is to present the major features and issues related to micropumps and microneedles, e.g., working principles, actuation methods, fabrication techniques, construction, performance parameters, failure analysis, testing, safety issues, applications, commercialization issues and future prospects. Based on the actuation mechanisms, the micropumps are classified into two main types, i.e., mechanical and non-mechanical micropumps. Microneedles can be categorized according to their structure, fabrication process, material, overall shape, tip shape, size, array density and application. The presented literature review on micropumps and microneedles will provide comprehensive information for researchers working on design and development of microfluidic devices for biomedical applications. PMID:21747700

Microfluidic device and method for focusing, segmenting, and dispensing of a fluid stream

DOEpatents

Jacobson, Stephen C [Knoxville, TN; Ramsey, J Michael [Knoxville, TN

2008-09-09

A microfluidic device and method for forming and dispensing minute volume segments of a material are described. In accordance with the present invention, a microfluidic device and method are provided for spatially confining the material in a focusing element. The device is also adapted for segmenting the confined material into minute volume segments, and dispensing a volume segment to a waste or collection channel. The device further includes means for driving the respective streams of sample and focusing fluids through respective channels into a chamber, such that the focusing fluid streams spatially confine the sample material. The device may also include additional means for driving a minute volume segment of the spatially confined sample material into a collection channel in fluid communication with the waste reservoir.

Microfluidic device and method for focusing, segmenting, and dispensing of a fluid stream

DOEpatents

Jacobson, Stephen C.; Ramsey, J. Michael

2004-09-14

A microfluidic device for forming and/or dispensing minute volume segments of a material is described. In accordance with one aspect of the present invention, a microfluidic device and method is provided for spatially confining the material in a focusing element. The device is also capable of segmenting the confined material into minute volume segments, and dispensing a volume segment to a waste or collection channel. The device further includes means for driving the respective streams of sample and focusing fluids through respective channels into a chamber, such that the focusing fluid streams spatially confine the sample material. The device may also include additional means for driving a minute volume segment of the spatially confined sample material into a collection channel in fluid communication with the waste reservoir.

Thermally induced light-driven microfluidics using a MOEMS-based laser scanner for particle manipulation

NASA Astrophysics Data System (ADS)

Kremer, Matthias P.; Tortschanoff, Andreas

2014-03-01

One key challenge in the field of microfluidics and lab-on-a-chip experiments for biological or chemical applications is the remote manipulation of fluids, droplets and particles. These can be volume elements of reactants, particles coated with markers, cells or many others. Light-driven microfluidics is one way of accomplishing this challenge. In our work, we manipulated micrometre sized polystyrene beads in a microfluidic environment by inducing thermal flows. Therefore, the beads were held statically in an unstructured microfluidic chamber, containing a dyed watery solution. Inside this chamber, the beads were moved along arbitrary trajectories on a micrometre scale. The experiments were performed, using a MOEMS (micro-opto-electro-mechanical-systems)-based laser scanner with a variable focal length. This scanner system is integrated in a compact device, which is flexibly applicable to various microscope setups. The device utilizes a novel approach for varying the focal length, using an electrically tunable lens. A quasi statically driven MOEMS mirror is used for beam steering. The combination of a tunable lens and a dual axis micromirror makes the device very compact and robust and is capable of positioning the laser focus at any arbitrary location within a three dimensional working space. Hence, the developed device constitutes a valuable extension to manually executed microfluidic lab-on-chip experiments.

Fabrication of polyimide based microfluidic channels for biosensor devices

NASA Astrophysics Data System (ADS)

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

2015-03-01

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

Double emulsions from a capillary array injection microfluidic device.

PubMed

Shang, Luoran; Cheng, Yao; Wang, Jie; Ding, Haibo; Rong, Fei; Zhao, Yuanjin; Gu, Zhongze

2014-09-21

A facile microfluidic device was developed by inserting an annular capillary array into a collection channel for single-step emulsification of double emulsions. By inserting multiple inner-phase solutions into the capillary array, multicomponent double emulsions or microcapsules with inner droplets of different content could also be obtained from the device.

Mechanically activated artificial cell by using microfluidics

NASA Astrophysics Data System (ADS)

Ho, Kenneth K. Y.; Lee, Lap Man; Liu, Allen P.

2016-09-01

All living organisms sense mechanical forces. Engineering mechanosensitive artificial cell through bottom-up in vitro reconstitution offers a way to understand how mixtures of macromolecules assemble and organize into a complex system that responds to forces. We use stable double emulsion droplets (aqueous/oil/aqueous) to prototype mechanosensitive artificial cells. In order to demonstrate mechanosensation in artificial cells, we develop a novel microfluidic device that is capable of trapping double emulsions into designated chambers, followed by compression and aspiration in a parallel manner. The microfluidic device is fabricated using multilayer soft lithography technology, and consists of a control layer and a deformable flow channel. Deflections of the PDMS membrane above the main microfluidic flow channels and trapping chamber array are independently regulated pneumatically by two sets of integrated microfluidic valves. We successfully compress and aspirate the double emulsions, which result in transient increase and permanent decrease in oil thickness, respectively. Finally, we demonstrate the influx of calcium ions as a response of our mechanically activated artificial cell through thinning of oil. The development of a microfluidic device to mechanically activate artificial cells creates new opportunities in force-activated synthetic biology.

Neural Stem Cell Differentiation Using Microfluidic Device-Generated Growth Factor Gradient.

PubMed

Kim, Ji Hyeon; Sim, Jiyeon; Kim, Hyun-Jung

2018-04-11

Neural stem cells (NSCs) have the ability to self-renew and differentiate into multiple nervous system cell types. During embryonic development, the concentrations of soluble biological molecules have a critical role in controlling cell proliferation, migration, differentiation and apoptosis. In an effort to find optimal culture conditions for the generation of desired cell types in vitro , we used a microfluidic chip-generated growth factor gradient system. In the current study, NSCs in the microfluidic device remained healthy during the entire period of cell culture, and proliferated and differentiated in response to the concentration gradient of growth factors (epithermal growth factor and basic fibroblast growth factor). We also showed that overexpression of ASCL1 in NSCs increased neuronal differentiation depending on the concentration gradient of growth factors generated in the microfluidic gradient chip. The microfluidic system allowed us to study concentration-dependent effects of growth factors within a single device, while a traditional system requires multiple independent cultures using fixed growth factor concentrations. Our study suggests that the microfluidic gradient-generating chip is a powerful tool for determining the optimal culture conditions.

Plasma extraction rate enhancement scheme for a real-time and continuous blood plasma separation device using a sheathless cell concentrator

NASA Astrophysics Data System (ADS)

Kang, Dong-Hyun; Kim, Kyongtae; Kim, Yong-Jun

2018-02-01

Microfluidic devices for plasma extraction are popular because they offer the advantage of smaller reagent consumption compared to conventional centrifugations. The plasma yield (volume percentage of plasma that can be extracted) is an important factor for diagnoses in microdevices with small reagent consumptions. However, recently designed microfluidic devices tend to have a low plasma yield because they have been optimized to improve the purity of extracted plasma. Thus, these devices require large amounts of reagents, and this complexity has eliminated the advantage of microfluidic devices that can operate with only small amounts of reagents. We therefore propose a continuous, real-time, blood plasma separation device, for plasma extraction rate enhancements. Moreover, a blood plasma separation device was designed to achieve improved plasma yields with high-purity efficiency. To obtain a high plasma yield, microstructures were placed on the bottom side of the channel to increase the concentration of blood cells. Plasma separation was then accomplished via microfluidic networks based on the Zweifach-Fung effect. The proposed device was fabricated based on the polydimethylsiloxane molding process using the SU-8 microfluidic channel for the fabrication of the mold and bottom structures. Human blood diluted in a phosphate buffered saline solution (25% hematocrit) was injected into the inlet of the device. The purity efficiencies were approximately equal to 96% with a maximum of 96.75% at a flow rate of 2 µl min-1, while the plasma yield was approximately 59% with a maximum of 59.92% at a flow rate of 4 µl min-1. Compared to results obtained using other devices, our proposed device could obtain comparable or higher plasma purity and a high plasma yield.

Integration of reconfigurable potentiometric electrochemical sensors into a digital microfluidic platform.

PubMed

Farzbod, Ali; Moon, Hyejin

2018-05-30

This paper presents the demonstration of on-chip fabrication of a potassium-selective sensor array enabled by electrowetting on dielectric digital microfluidics for the first time. This demonstration proves the concept that electrochemical sensors can be seamlessly integrated with sample preparation units in a digital microfluidic platform. More significantly, the successful on-chip fabrication of a sensor array indicates that sensors become reconfigurable and have longer lifetime in a digital microfluidic platform. The on-chip fabrication of ion-selective electrodes includes electroplating Ag followed by forming AgCl layer by chemical oxidation and depositing a thin layer of desired polymer-based ion selective membrane on one of the sensor electrodes. In this study, potassium ionophores work as potassium ion channels and make the membrane selective to potassium ions. This selectiveness results in the voltage difference across the membrane layer, which is correlated with potassium ion concentration. The calibration curve of the fabricated potassium-selective electrode demonstrates the slope of 58 mV/dec for potassium concentration in KCl sample solutions and shows good agreement with the ideal Nernstian response. The proposed sensor platform is an outstanding candidate for a portable home-use for continuous monitoring of ions thanks to its advantages such as easy automation of sample preparation and detection processes, elongated sensor lifetime, minimal membrane and sample consumption, and user-definable/reconfigurable sensor array. Copyright © 2018 Elsevier B.V. All rights reserved.

Direct-referencing Two-dimensional-array Digital Microfluidics Using Multi-layer Printed Circuit Board

PubMed Central

Gong, Jian; Kim, Chang-Jin “CJ”

2008-01-01

Digital (i.e. droplet-based) microfluidics, by the electrowetting-on-dielectric (EWOD) mechanism, has shown great potential for a wide range of applications, such as lab-on-a-chip. While most reported EWOD chips use a series of electrode pads essentially in one-dimensional line pattern designed for specific tasks, the desired universal chips allowing user-reconfigurable paths would require the electrode pads in two-dimensional pattern. However, to electrically access the electrode pads independently, conductive lines need to be fabricated underneath the pads in multiple layers, raising a cost issue especially for disposable chip applications. In this article, we report the building of digital microfluidic plates based on a printed-circuit-board (PCB), in which multilayer electrical access lines were created inexpensively using mature PCB technology. However, due to its surface topography and roughness and resulting high resistance against droplet movement, as-fabricated PCB surfaces require unacceptably high (~500 V) voltages unless coated with or immersed in oil. Our goal is EWOD operations of aqueous droplets not only on oil-covered but also on dry surfaces. To meet varying levels of performances, three types of gradually complex post-PCB microfabrication processes are developed and evaluated. By introducing land-grid-array (LGA) sockets in the packaging, a scalable digital microfluidics system with reconfigurable and low-cost chip is also demonstrated. PMID:19234613

Macro to Nano: A Simple Method for Transporting Cultured Cells from Milliliter Scale to Nanoliter Scale

PubMed Central

Seale, Kevin T.; Faley, Shannon L.; Chamberlain, Jeff; Wikswo, John P.

2013-01-01

Microfluidic devices are well suited for the study of metabolism and paracrine and autocrine signaling because they allow steady or intermittent perfusion of biological cells at cell densities that approach those in living tissue. They also enable the study of small populations of rare cells. However, it can be difficult to introduce the cells into a microfluidic device to achieve and control such densities without damaging or clumping the cells. We describe simple procedures that address the problem of efficient introduction of cells and cell culture media into microfluidic devices using small bore polyetheretherketone (PEEK) tubing and Hamilton gastight syringes. Suspension or adherent cells grown in cell culture flasks are centrifuged and extracted directly from the centrifuge pellet into the end of the PEEK tubing by aspiration. The tube end is then coupled to pre-punched channels in the polydimethylsiloxane (PDMS) microfluidic device by friction fitting. Controlled depression of the syringe plunger expels the cells into the microfluidic device only seconds following aspiration. The gastight syringes and PEEK tubing with PEEK fittings provide a noncompliant source of pressure and suction with a rapid response time that is well suited for short-term intra-microfluidic cellular studies. The benefits of this method are its simplicity, modest expense, the short preparation time required for loading appropriate numbers of cells, and the applicability of the technique to small quantities of rare or expensive cells. This should in turn lead to new applications of microfludic devices to biology and medicine. PMID:20511682

Microfluidic electrochemical reactors

DOEpatents

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

2011-03-22

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

In-air microfluidics: Drop and jet coalescence enables rapid multi-phase 3D printing

NASA Astrophysics Data System (ADS)

Visser, Claas Willem; Kamperman, Tom; Lohse, Detlef; Karperien, Marcel; University of Twente Collaboration

2016-11-01

For the first time, we connect and integrate the fields of microfluidics and additive manufacturing, by presenting a unifying technology that we call In-air microfluidics (IAMF). We impact two liquid jets or a jet and a droplet train while flying in-air, and control their coalescence and solidification. This approach enables producing monodisperse emulsions, particles, and fibers with controlled shape and size (10 to 300 µm) and production rates 100x higher than droplet microfluidics. A single device is sufficient to process a variety of materials, and to produce different particle or fiber shapes, in marked contrast to current microfluidic devices or printers. In-air microfluidics also enables rapid deposition onto substrates, for example to form 3D printed (bio)materials which are partly-liquid but still shape-stable.

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

PubMed

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

2017-02-15

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

Method Of Packaging And Assembling Electro-Microfluidic Devices

DOEpatents

Benavides, Gilbert L.; Galambos, Paul C.; Emerson, John A.; Peterson, Kenneth A.; Giunta, Rachel K.; Zamora, David Lee; Watson, Robert D.

2004-11-23

A new architecture for packaging surface micromachined electro-microfluidic devices is presented. This architecture relies on two scales of packaging to bring fluid to the device scale (picoliters) from the macro-scale (microliters). The architecture emulates and utilizes electronics packaging technology. The larger package consists of a circuit board with embedded fluidic channels and standard fluidic connectors (e.g. Fluidic Printed Wiring Board). The embedded channels connect to the smaller package, an Electro-Microfluidic Dual-Inline-Package (EMDIP) that takes fluid to the microfluidic integrated circuit (MIC). The fluidic connection is made to the back of the MIC through Bosch-etched holes that take fluid to surface micromachined channels on the front of the MIC. Electrical connection is made to bond pads on the front of the MIC.

A small-scale, rolled-membrane microfluidic artificial lung designed towards future large area manufacturing.

PubMed

Thompson, A J; Marks, L H; Goudie, M J; Rojas-Pena, A; Handa, H; Potkay, J A

2017-03-01

Artificial lungs have been used in the clinic for multiple decades to supplement patient pulmonary function. Recently, small-scale microfluidic artificial lungs (μAL) have been demonstrated with large surface area to blood volume ratios, biomimetic blood flow paths, and pressure drops compatible with pumpless operation. Initial small-scale microfluidic devices with blood flow rates in the μ l/min to ml/min range have exhibited excellent gas transfer efficiencies; however, current manufacturing techniques may not be suitable for scaling up to human applications. Here, we present a new manufacturing technology for a microfluidic artificial lung in which the structure is assembled via a continuous "rolling" and bonding procedure from a single, patterned layer of polydimethyl siloxane (PDMS). This method is demonstrated in a small-scale four-layer device, but is expected to easily scale to larger area devices. The presented devices have a biomimetic branching blood flow network, 10  μ m tall artificial capillaries, and a 66  μ m thick gas transfer membrane. Gas transfer efficiency in blood was evaluated over a range of blood flow rates (0.1-1.25 ml/min) for two different sweep gases (pure O 2 , atmospheric air). The achieved gas transfer data closely follow predicted theoretical values for oxygenation and CO 2 removal, while pressure drop is marginally higher than predicted. This work is the first step in developing a scalable method for creating large area microfluidic artificial lungs. Although designed for microfluidic artificial lungs, the presented technique is expected to result in the first manufacturing method capable of simply and easily creating large area microfluidic devices from PDMS.

A microfluidic device for dry sample preservation in remote settings.

PubMed

Begolo, Stefano; Shen, Feng; Ismagilov, Rustem F

2013-11-21

This paper describes a microfluidic device for dry preservation of biological specimens at room temperature that incorporates chemical stabilization matrices. Long-term stabilization of samples is crucial for remote medical analysis, biosurveillance, and archiving, but the current paradigm for transporting remotely obtained samples relies on the costly "cold chain" to preserve analytes within biospecimens. We propose an alternative approach that involves the use of microfluidics to preserve samples in the dry state with stabilization matrices, developed by others, that are based on self-preservation chemistries found in nature. We describe a SlipChip-based device that allows minimally trained users to preserve samples with the three simple steps of placing a sample at an inlet, closing a lid, and slipping one layer of the device. The device fills automatically, and a pre-loaded desiccant dries the samples. Later, specimens can be rehydrated and recovered for analysis in a laboratory. This device is portable, compact, and self-contained, so it can be transported and operated by untrained users even in limited-resource settings. Features such as dead-end and sequential filling, combined with a "pumping lid" mechanism, enable precise quantification of the original sample's volume while avoiding overfilling. In addition, we demonstrated that the device can be integrated with a plasma filtration module, and we validated device operations and capabilities by testing the stability of purified RNA solutions. These features and the modularity of this platform (which facilitates integration and simplifies operation) would be applicable to other microfluidic devices beyond this application. We envision that as the field of stabilization matrices develops, microfluidic devices will be useful for cost-effectively facilitating remote analysis and biosurveillance while also opening new opportunities for diagnostics, drug development, and other medical fields.

Single-cell cloning and expansion of human induced pluripotent stem cells by a microfluidic culture device.

PubMed

Matsumura, Taku; Tatsumi, Kazuya; Noda, Yuichiro; Nakanishi, Naoyuki; Okonogi, Atsuhito; Hirano, Kunio; Li, Liu; Osumi, Takashi; Tada, Takashi; Kotera, Hidetoshi

2014-10-10

The microenvironment of cells, which includes basement proteins, shear stress, and extracellular stimuli, should be taken into consideration when examining physiological cell behavior. Although microfluidic devices allow cellular responses to be analyzed with ease at the single-cell level, few have been designed to recover cells. We herein demonstrated that a newly developed microfluidic device helped to improve culture conditions and establish a clonality-validated human pluripotent stem cell line after tracing its growth at the single-cell level. The device will be a helpful tool for capturing various cell types in the human body that have not yet been established in vitro. Copyright © 2014 Elsevier Inc. All rights reserved.

Gravity-oriented microfluidic device for uniform and massive cell spheroid formation

PubMed Central

Lee, Kangsun; Kim, Choong; Young Yang, Jae; Lee, Hun; Ahn, Byungwook; Xu, Linfeng; Yoon Kang, Ji; Oh, Kwang W.

2012-01-01

We propose a simple method for forming massive and uniform three-dimensional (3-D) cell spheroids in a multi-level structured microfluidic device by gravitational force. The concept of orienting the device vertically has allowed spheroid formation, long-term perfusion, and retrieval of the cultured spheroids by user-friendly standard pipetting. We have successfully formed, perfused, and retrieved uniform, size-controllable, well-conditioned spheroids of human embryonic kidney 293 cells (HEK 293) in the gravity-oriented microfluidic device. We expect the proposed method will be a useful tool to study in-vitro 3-D cell models for the proliferation, differentiation, and metabolism of embryoid bodies or tumours. PMID:22662098

Lifespan-on-a-chip: microfluidic chambers for performing lifelong observation of C. elegans†

PubMed Central

Hulme, S. Elizabeth; Shevkoplyas, Sergey S.; McGuigan, Alison P.; Apfeld, Javier; Fontana, Walter

2011-01-01

This article describes the fabrication of a microfluidic device for the liquid culture of many individual nematode worms (Caenorhabditis elegans) in separate chambers. Each chamber houses a single worm from the fourth larval stage until death, and enables examination of a population of individual worms for their entire adult lifespans. Adjacent to the chambers, the device includes microfluidic worm clamps, which enable periodic, temporary immobilization of each worm. The device made it possible to track changes in body size and locomotion in individual worms throughout their lifespans. This ability to perform longitudinal measurements within the device enabled the identification of age-related phenotypic changes that correlate with lifespan in C. elegans. PMID:20162234

Microfluidic structures and methods for integrating a functional component into a microfluidic device

DOEpatents

Simmons, Blake [San Francisco, CA; Domeier, Linda [Danville, CA; Woo, Noble [San Gabriet, CA; Shepodd, Timothy [Livermore, CA; Renzi, Ronald F [Tracy, CA

2008-04-01

Injection molding is used to form microfluidic devices with integrated functional components. One or more functional components are placed in a mold cavity which is then closed. Molten thermoplastic resin is injected into the mold and then cooled, thereby forming a solid substrate including the functional component(s). The solid substrate including the functional component(s) is then bonded to a second substrate which may include microchannels or other features.

Multi-depth valved microfluidics for biofilm segmentation

NASA Astrophysics Data System (ADS)

Meyer, M. T.; Subramanian, S.; Kim, Y. W.; Ben-Yoav, H.; Gnerlich, M.; Gerasopoulos, K.; Bentley, W. E.; Ghodssi, R.

2015-09-01

Bacterial biofilms present a societal challenge, as they occur in the majority of infections but are highly resistant to both immune mechanisms and traditional antibiotics. In the pursuit of better understanding biofilm biology for developing new treatments, there is a need for streamlined, controlled platforms for biofilm growth and evaluation. We leverage advantages of microfluidics to develop a system in which biofilms are formed and sectioned, allowing parallel assays on multiple sections of one biofilm. A microfluidic testbed with multiple depth profiles was developed to accommodate biofilm growth and sectioning by hydraulically actuated valves. In realization of the platform, a novel fabrication technique was developed for creating multi-depth microfluidic molds using sequentially patterned photoresist separated and passivated by conformal coatings using atomic layer deposition. Biofilm thickness variation within three separately tested devices was less than 13% of the average thickness in each device, while variation between devices was 23% of the average thickness. In a demonstration of parallel experiments performed on one biofilm within one device, integrated valves were used to trisect the uniform biofilms with one section maintained as a control, and two sections exposed to different concentrations of sodium dodecyl sulfate. The technology presented here for multi-depth microchannel fabrication can be used to create a host of microfluidic devices with diverse architectures. While this work focuses on one application of such a device in biofilm sectioning for parallel experimentation, the tailored architectures enabled by the fabrication technology can be used to create devices that provide new biological information.

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

PubMed

Watanabe, Masashi

2011-04-07

A microfluidic device for liquid-liquid extraction was quickly produced using an office inkjet printer. An advantage of this method is that normal end users, who are not familiar with microfabrication, can produce their original microfluidic devices by themselves. In this method, the printer draws a line on a hydrophobic and oil repellent surface using hydrophilic ink. This line directs a fluid, such as water or xylene, to form a microchannel along the printed line. Using such channels, liquid-liquid extraction was successfully performed under concurrent and countercurrent flow conditions. © The Royal Society of Chemistry 2011

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

PubMed

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

2016-01-01

Microfluidic devices enable precise quantification of the interactions between anti-cancer bacteria and tumor tissue. Direct observation of bacterial movement and gene expression in tissue is difficult with either monolayers of cells or tumor-bearing mice. Quantification of these interactions is necessary to understand the inherent mechanisms of bacterial targeting and to develop modified organisms with enhanced therapeutic properties. Here we describe the procedures for designing, printing, and assembling microfluidic tumor-on-a-chip devices. We also describe the procedures for inserting three-dimensional tumor-cell masses, exposure to bacteria, and analyzing the resultant images.

Membraneless seawater desalination

DOEpatents

Crooks, Richard A.; Knust, Kyle N.; Perdue, Robbyn K.

2018-04-03

Disclosed are microfluidic devices and systems for the desalination of water. The devices and systems can include an electrode configured to generate an electric field gradient in proximity to an intersection formed by the divergence of two microfluidic channels from an inlet channel. Under an applied bias and in the presence of a pressure driven flow of saltwater, the electric field gradient can preferentially direct ions in saltwater into one of the diverging microfluidic channels, while desalted water flows into second diverging channel. Also provided are methods of using the devices and systems described herein to decrease the salinity of water.

Design and characterization of hydrogel-based microfluidic devices with biomimetic solute transport networks

PubMed Central

Koo, Hyung-Jun

2017-01-01

Hydrogel could serve as a matrix material of new classes of solar cells and photoreactors with embedded microfluidic networks. These devices mimic the structure and function of plant leaves, which are a natural soft matter based microfluidic system. These unusual microfluidic-hydrogel devices with fluid-penetrable medium operate on the basis of convective-diffusive mechanism, where the liquid is transported between the non-connected channels via molecular permeation through the hydrogel. We define three key designs of such hydrogel devices, having linear, T-shaped, and branched channels and report results of numerical simulation of the process of their infusion with solute carried by the incoming fluid. The computational procedure takes into account both pressure-driven convection and concentration gradient-driven diffusion in the permeable gel matrix. We define the criteria for evaluation of the fluid infusion rate, uniformity, solute loss by outflow and overall performance. The T-shaped channel network was identified as the most efficient one and was improved further by investigating the effect of the channel-end secondary branches. Our parallel experimental data on the pattern of solute infusions are in excellent agreement with the simulation. These network designs can be applied to a broad range of novel microfluidic materials and soft matter devices with distributed microchannel networks. PMID:28396708

Microfluidic platform for single cell analysis under dynamic spatial and temporal stimulation.

PubMed

Song, Jiyoung; Ryu, Hyunryul; Chung, Minhwan; Kim, Youngtaek; Blum, Yannick; Lee, Sung Sik; Pertz, Olivier; Jeon, Noo Li

2018-05-01

Recent research on cellular responses is shifting from static observations recorded under static stimuli to real-time monitoring in a dynamic environment. Since cells sense and interact with their surrounding microenvironment, an experimental platform where dynamically changing cellular microenvironments should be recreated in vitro. There has been a lack of microfluidic devices to support spatial and temporal stimulations in a simple and robust manner. Here, we describe a microfluidic device that generates dynamic chemical gradients and pulses in both space and time using a single device. This microfluidic device provides at least 12h of continuous stimulations that can be used to observe responses from mammalian cells. Combination of the microfluidic de-vice with live-cell imaging facilitates real-time observation of dynamic cellular response at single cell level. Using stable HEK cells with biosensors, ERK (Extracellular signal-Regulated Kinase) activities were observed un-der the pulsatile and ramping stimulations of EGF (Epidermal Growth Factor). We quantified ERK activation even at extremely low EGF concentration (0.0625µg/ml), which can not be observed using conventional techniques such as western blot. Cytoskeleton re-arrangement of the 3T3 fibroblast (stable transfection with Lifeact-GFP) was compared under abrupt and gradually changing gradient of PDGF. Copyright © 2017 Elsevier B.V. All rights reserved.

Microfluidic platform for multiplexed detection in single cells and methods thereof

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wu, Meiye; Singh, Anup K.

The present invention relates to a microfluidic device and platform configured to conduct multiplexed analysis within the device. In particular, the device allows multiple targets to be detected on a single-cell level. Also provided are methods of performing multiplexed analyses to detect one or more target nucleic acids, proteins, and post-translational modifications.

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

NASA Astrophysics Data System (ADS)

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

2016-05-01

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

Ultrasensitive detection of lysozyme in droplet-based microfluidic devices.

PubMed

Giuffrida, Maria Chiara; Cigliana, Giovanni; Spoto, Giuseppe

2018-05-01

Lysozyme (LYS) is a bacteriolytic enzyme, available in secretions such as saliva, tears and human milk. LYS is an important defence molecule of the innate immune system, and its overexpression can be a consequence of diseases such as leukemia, kidney disease and sarcoidosis. This paper reports on a digital microfluidic-based approach that combines the gold nanoparticle-enhanced chemiluminescence with aptamer interaction to detect human lysozyme into droplets 20 nanoliters in volume. The described method allows identifying LYS with a 44.6 femtomolar limit of detection, using sample volume as low as 1μL and detection time in the range of 10min. We used luminol to generate the chemiluminescence and demonstrated that the compartmentalization of LYS in droplets also comprising gold nanoparticles provided enhanced luminescence. We functionalized the gold nanoparticles with a thiolated aptamer to achieve the required selectivity that allowed us to detect LYS in human serum. Copyright © 2017 Elsevier B.V. All rights reserved.

A versatile valving toolkit for automating fluidic operations in paper microfluidic devices.

PubMed

Toley, Bhushan J; Wang, Jessica A; Gupta, Mayuri; Buser, Joshua R; Lafleur, Lisa K; Lutz, Barry R; Fu, Elain; Yager, Paul

2015-03-21

Failure to utilize valving and automation techniques has restricted the complexity of fluidic operations that can be performed in paper microfluidic devices. We developed a toolkit of paper microfluidic valves and methods for automatic valve actuation using movable paper strips and fluid-triggered expanding elements. To the best of our knowledge, this is the first functional demonstration of this valving strategy in paper microfluidics. After introduction of fluids on devices, valves can actuate automatically after a) a certain period of time, or b) the passage of a certain volume of fluid. Timing of valve actuation can be tuned with greater than 8.5% accuracy by changing lengths of timing wicks, and we present timed on-valves, off-valves, and diversion (channel-switching) valves. The actuators require ~30 μl fluid to actuate and the time required to switch from one state to another ranges from ~5 s for short to ~50 s for longer wicks. For volume-metered actuation, the size of a metering pad can be adjusted to tune actuation volume, and we present two methods - both methods can achieve greater than 9% accuracy. Finally, we demonstrate the use of these valves in a device that conducts a multi-step assay for the detection of the malaria protein PfHRP2. Although slightly more complex than devices that do not have moving parts, this valving and automation toolkit considerably expands the capabilities of paper microfluidic devices. Components of this toolkit can be used to conduct arbitrarily complex, multi-step fluidic operations on paper-based devices, as demonstrated in the malaria assay device.

A versatile valving toolkit for automating fluidic operations in paper microfluidic devices

PubMed Central

Toley, Bhushan J.; Wang, Jessica A.; Gupta, Mayuri; Buser, Joshua R.; Lafleur, Lisa K.; Lutz, Barry R.; Fu, Elain; Yager, Paul

2015-01-01

Failure to utilize valving and automation techniques has restricted the complexity of fluidic operations that can be performed in paper microfluidic devices. We developed a toolkit of paper microfluidic valves and methods for automatic valve actuation using movable paper strips and fluid-triggered expanding elements. To the best of our knowledge, this is the first functional demonstration of this valving strategy in paper microfluidics. After introduction of fluids on devices, valves can actuate automatically a) after a certain period of time, or b) after the passage of a certain volume of fluid. Timing of valve actuation can be tuned with greater than 8.5% accuracy by changing lengths of timing wicks, and we present timed on-valves, off-valves, and diversion (channel-switching) valves. The actuators require ~30 μl fluid to actuate and the time required to switch from one state to another ranges from ~5 s for short to ~50s for longer wicks. For volume-metered actuation, the size of a metering pad can be adjusted to tune actuation volume, and we present two methods – both methods can achieve greater than 9% accuracy. Finally, we demonstrate the use of these valves in a device that conducts a multi-step assay for the detection of the malaria protein PfHRP2. Although slightly more complex than devices that do not have moving parts, this valving and automation toolkit considerably expands the capabilities of paper microfluidic devices. Components of this toolkit can be used to conduct arbitrarily complex, multi-step fluidic operations on paper-based devices, as demonstrated in the malaria assay device. PMID:25606810

Magnetic Tethering of Microswimmers in Microfluidic Devices

NASA Astrophysics Data System (ADS)

Chawan, Aschvin; Jana, Saikat; Ghosh, Suvojit; Jung, Sunghwan; Puri, Ishwar

2013-03-01

Exercising control over animal locomotion is well known in the macro world. In the micro-scale world, such methods require more sophistication. We magnetize Paramecium multimicronucleatum by internalization of magnetite nanoparticles coated with bovine serum albumin (BSA). This enables control of their motion in a microfluidic device using a magnetic field. Miniature permanent magnets embedded within the device are used to tether the magnetized organisms to specific locations along a micro-channel. Ciliary beatings of the microswimmer generate shear flows nearby. We apply this setup to enhance cross-stream mixing in a microfluidic device by supplementing molecular diffusion. The device is similar to an active micromixer but requires no external power sources or artificial actuators. We optically characterize the effectiveness of the mechanism in a variety of flow situations.

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

PubMed

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

2015-12-01

Low-cost assays have broad applications ranging from human health diagnostics and food safety inspection to environmental analysis. Hence, low-cost assays are especially attractive for rural areas and developing countries, where financial resources are limited. Recently, paper-based microfluidic devices have emerged as a low-cost platform which greatly accelerates the point of care (POC) analysis in low-resource settings. This paper reviews recent advances of low-cost bioanalysis on paper-based microfluidic platforms, including fully paper-based and paper hybrid microfluidic platforms. In this review paper, we first summarized the fabrication techniques of fully paper-based microfluidic platforms, followed with their applications in human health diagnostics and food safety analysis. Then we highlighted paper hybrid microfluidic platforms and their applications, because hybrid platforms could draw benefits from multiple device substrates. Finally, we discussed the current limitations and perspective trends of paper-based microfluidic platforms for low-cost assays. Copyright © 2015 Elsevier B.V. All rights reserved.

Note: On-chip multifunctional fluorescent-magnetic Janus helical microswimmers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hwang, G., E-mail: gilgueng.hwang@lpn.cnrs.fr; Decanini, D.; Leroy, L.

Microswimmers integrated into microfluidic devices that are capable of self-illumination through fluorescence could revolutionize many aspects of technology, especially for biological applications. Few illumination and propulsion techniques of helical microswimmers inside microfluidic channels have been demonstrated. This paper presents the fabrication, detachment, and magnetic propulsions of multifunctional fluorescent-magnetic helical microswimmers integrated inside microfluidics. The fabrication process is based on two-photon laser lithography to pattern 3-D nanostructures from fluorescent photoresist coupled with conventional microfabrication techniques for magnetic thin film deposition by shadowing. After direct integration inside a microfluidic device, injected gas bubble allows gentle detachment of the integrated helical microswimmers whosemore » magnetic propulsion can then be directly applied inside the microfluidic channel using external electromagnetic coil setup. With their small scale, fluorescence, excellent resistance to liquid/gas surface tension, and robust propulsion capability inside the microfluidic channel, the microswimmers can be used as high-resolution and large-range mobile micromanipulators inside microfluidic channels.« less

Biosensors-on-chip: a topical review

NASA Astrophysics Data System (ADS)

Chen, Sensen; Shamsi, Mohtashim H.

2017-08-01

This review will examine the integration of two fields that are currently at the forefront of science, i.e. biosensors and microfluidics. As a lab-on-a-chip (LOC) technology, microfluidics has been enriched by the integration of various detection tools for analyte detection and quantitation. The application of such microfluidic platforms is greatly increased in the area of biosensors geared towards point-of-care diagnostics. Together, the merger of microfluidics and biosensors has generated miniaturized devices for sample processing and sensitive detection with quantitation. We believe that microfluidic biosensors (biosensors-on-chip) are essential for developing robust and cost effective point-of-care diagnostics. This review is relevant to a variety of disciplines, such as medical science, clinical diagnostics, LOC technologies including MEMs/NEMs, and analytical science. Specifically, this review will appeal to scientists working in the two overlapping fields of biosensors and microfluidics, and will also help new scientists to find their directions in developing point-of-care devices.

Microfluidics for rapid cytokeratin immunohistochemical staining in frozen sections.

PubMed

Brajkovic, Saska; Dupouy, Diego G; de Leval, Laurence; Gijs, Martin Am

2017-08-01

Frozen sections (FS) of tumor samples represent a cornerstone of pathological intraoperative consultation and have an important role in the microscopic analysis of specimens during surgery. So far, immunohistochemical (IHC) stainings on FS have been demonstrated for a few markers using manual methods. Microfluidic technologies have proven to bring substantial improvement in many fields of diagnostics, though only a few microfluidic devices have been designed to improve the performance of IHC assays. In this work, we show optimization of a complete pan-cytokeratin chromogenic immunostaining protocol on FS using a microfluidic tissue processor into a protocol taking <12 min. Our results showed specificity and low levels of background. The dimensions of the microfluidic prototype device are compatible with the space constraints of an intraoperative pathology laboratory. We therefore anticipate that the adoption of microfluidic technologies in the field of surgical pathology can significantly improve the way FSs influence surgical procedures.

Microfluidic strategies for understanding the mechanics of cells and cell-mimetic systems

PubMed Central

Dahl, Joanna B.; Lin, Jung-Ming G.; Muller, Susan J.; Kumar, Sanjay

2016-01-01

Microfluidic systems are attracting increasing interest for the high-throughput measurement of cellular biophysical properties and for the creation of engineered cellular microenvironments. Here we review recent applications of microfluidic technologies to the mechanics of living cells and synthetic cell-mimetic systems. We begin by discussing the use of microfluidic devices to dissect the mechanics of cellular mimics such as capsules and vesicles. We then explore applications to circulating cells, including erythrocytes and other normal blood cells, and rare populations with potential disease diagnostic value, such as circulating tumor cells. We conclude by discussing how microfluidic devices have been used to investigate the mechanics, chemotaxis, and invasive migration of adherent cells. In these ways, microfluidic technologies represent an increasingly important toolbox for investigating cellular mechanics and motility at high throughput and in a format that lends itself to clinical translation. PMID:26134738

Microfluidics for rapid cytokeratin immunohistochemical staining in frozen sections

PubMed Central

Brajkovic, Saska; Dupouy, Diego G.; de Leval, Laurence; Gijs, Martin A. M.

2017-01-01

Frozen sections (FS) of tumor samples represent a cornerstone of pathological intraoperative consultation and play an important role in the microscopic analysis of specimens during surgery. So far, immunohistochemical (IHC) stainings on FS have been demonstrated for a few markers using manual methods. Microfluidic technologies have proven to bring substantial improvement in many fields of diagnostics, though only a few microfluidic devices have been designed to improve the performance of IHC assays. In this work, we show optimization of a complete pan-cytokeratin chromogenic immunostaining protocol on FS using a microfluidic tissue processor, into a protocol taking less than 12 minutes. Our results showed specificity and low levels of background. The dimensions of the microfluidic prototype device are compatible with the space constraints of an intraoperative pathology laboratory. We therefore anticipate that the adoption of microfluidic technologies in the field of surgical pathology can significantly improve the way FSs influence surgical procedures. PMID:28553936

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.

Microfluidic devices for the controlled manipulation of small volumes

DOEpatents

Ramsey, J Michael [Knoxville, TN; Jacobson, Stephen C [Knoxville, TN

2003-02-25

A method for conducting a broad range of biochemical analyses or manipulations on a series of nano- to subnanoliter reaction volumes and an apparatus for carrying out the same are disclosed. The method and apparatus are implemented on a fluidic microchip to provide high serial throughput. The method and device of the invention also lend themselves to multiple parallel analyses and manipulation to provide greater throughput for the generation of biochemical information. In particular, the disclosed device is a microfabricated channel device that can manipulate nanoliter or subnanoliter biochemical reaction volumes in a controlled manner to produce results at rates of 1 to 10 Hz per channel. The individual reaction volumes are manipulated in serial fashion analogous to a digital shift register. The method and apparatus according to this invention have application to such problems as screening molecular or cellular targets using single beads from split-synthesis combinatorial libraries, screening single cells for RNA or protein expression, genetic diagnostic screening at the single cell level, or performing single cell signal transduction studies.

SAXS on a chip: from dynamics of phase transitions to alignment phenomena at interfaces studied with microfluidic devices.

PubMed

Silva, Bruno F B

2017-09-13

The field of microfluidics offers attractive possibilities to perform novel experiments that are difficult (or even impossible) to perform using conventional bulk and surface-based methods. Such attractiveness comes from several important aspects inherent to these miniaturized devices. First, the flow of fluids under submillimeter confinement typically leads to a drop of inertial forces, meaning that turbulence is practically suppressed. This leads to predictable and controllable flow profiles, along with well-defined chemical gradients and stress fields that can be used for controlled mixing and actuation on the micro and nanoscale. Secondly, intricate microfluidic device designs can be fabricated using cleanroom standard procedures. Such intricate geometries can take diverse forms, designed by researchers to perform complex tasks, that require exquisite control of flow of several components and gradients, or to mimic real world examples, facilitating the establishment of more realistic models. Thirdly, microfluidic devices are usually compatible with in situ or integrated characterization methods that allow constant real-time monitoring of the processes occurring inside the microchannels. This is very different from typical bulk-based methods, where usually one can only observe the final result, or otherwise, take quick snapshots of the evolving process or take aliquots to be analyzed separately. Altogether, these characteristics inherent to microfluidic devices provide researchers with a set of tools that allow not only exquisite control and manipulation of materials at the micro and nanoscale, but also observation of these effects. In this review, we will focus on the use and prospects of combining microfluidic devices with in situ small-angle X-ray scattering (and related techniques such as small-angle neutron scattering and X-ray photon correlation spectroscopy), and their enormous potential for physical-chemical research, mainly in self-assembly and phase-transitions, and surface characterization.

An integrated fiberoptic-microfluidic device for agglutination detection and blood typing.

PubMed

Ramasubramanian, Melur K; Alexander, Stewart P

2009-02-01

In this paper, an integrated fiberoptic-microfluidic device for the detection of agglutination for blood type cross-matching has been described. The device consists of a straight microfluidic channel through with a reacted RBC suspension is pumped with the help of a syringe pump. The flow intersects an optical path created by an emitter-received fiber optic pair integrated into the microfluidic device. A 650 nm laser diode is used as the light source and a silicon photodiode is used to detect the light intensity. The spacing between the tips of the two optic fibers can be adjusted. When fiber spacing is large and the concentration of the suspension is high, scattering phenomenon becomes the dominant mechanism for agglutination detection while at low concentrations and small spacing, optointerruption becomes the dominant mechanism. An agglutination strength factor (ASF) is calculated from the data. Studies with a variety of blood types indicate that the sensing method correctly identifies the agglutination reaction in all cases. A disposable integrated device can be designed for future implementation of the method for near-bedside pre-transfusion check.

Micromilling: A method for ultra-rapid prototyping of plastic microfluidic devices

PubMed Central

Guckenberger, David J.; de Groot, Theodorus E.; Wan, Alwin M.D.; Beebe, David J.; Young, Edmond W. K.

2015-01-01

This tutorial review offers protocols, tips, insight, and considerations for practitioners interested in using micromilling to create microfluidic devices. The objective is to provide a potential user with information to guide them on whether micromilling would fill a specific need within their overall fabrication strategy. Comparisons are made between micromilling and other common fabrication methods for plastics in terms of technical capabilities and cost. The main discussion focuses on “how-to” aspects of micromilling, to enable a user to select proper equipment and tools, and obtain usable microfluidic parts with minimal start-up time and effort. The supplementary information provides more extensive discussion on CNC mill setup, alignment, and programming. We aim to reach an audience with minimal prior experience in milling, but with strong interests in fabrication of microfluidic devices. PMID:25906246

Method for making electro-fluidic connections in microfluidic devices

DOEpatents

Frye-Mason, Gregory C.; Martinez, David; Manginell, Ronald P.; Heller, Edwin J.; Chanchani, Rajen

2004-08-10

A method for forming electro-fluidic interconnections in microfluidic devices comprises forming an electrical connection between matching bond pads on a die containing an active electrical element and a microfluidic substrate and forming a fluidic seal ring that circumscribes the active electrical element and a fluidic feedthrough. Preferably, the electrical connection and the seal ring are formed in a single bonding step. The simple method is particularly useful for chemical microanalytical systems wherein a plurality of microanalytical components, such as a chemical preconcentrator, a gas chromatography column, and a surface acoustic wave detector, are fluidically interconnected on a hybrid microfluidic substrate having electrical connection to external support electronics.

Microfluidic size separation of cells and particles using a swinging bucket centrifuge.

PubMed

Yeo, Joo Chuan; Wang, Zhiping; Lim, Chwee Teck

2015-09-01

Biomolecular separation is crucial for downstream analysis. Separation technique mainly relies on centrifugal sedimentation. However, minuscule sample volume separation and extraction is difficult with conventional centrifuge. Furthermore, conventional centrifuge requires density gradient centrifugation which is laborious and time-consuming. To overcome this challenge, we present a novel size-selective bioparticles separation microfluidic chip on a swinging bucket minifuge. Size separation is achieved using passive pressure driven centrifugal fluid flows coupled with centrifugal force acting on the particles within the microfluidic chip. By adopting centrifugal microfluidics on a swinging bucket rotor, we achieved over 95% efficiency in separating mixed 20 μm and 2 μm colloidal dispersions from its liquid medium. Furthermore, by manipulating the hydrodynamic resistance, we performed size separation of mixed microbeads, achieving size efficiency of up to 90%. To further validate our device utility, we loaded spiked whole blood with MCF-7 cells into our microfluidic device and subjected it to centrifugal force for a mere duration of 10 s, thereby achieving a separation efficiency of over 75%. Overall, our centrifugal microfluidic device enables extremely rapid and label-free enrichment of different sized cells and particles with high efficiency.

Low-cost feedback-controlled syringe pressure pumps for microfluidics applications.

PubMed

Lake, John R; Heyde, Keith C; Ruder, Warren C

2017-01-01

Microfluidics are widely used in research ranging from bioengineering and biomedical disciplines to chemistry and nanotechnology. As such, there are a large number of options for the devices used to drive and control flow through microfluidic channels. Commercially available syringe pumps are probably the most commonly used instruments for this purpose, but are relatively high-cost and have inherent limitations due to their flow profiles when they are run open-loop. Here, we present a low-cost ($110) syringe pressure pump that uses feedback control to regulate the pressure into microfluidic chips. Using an open-source microcontroller board (Arduino), we demonstrate an easily operated and programmable syringe pump that can be run using either a PID or bang-bang control method. Through feedback control of the pressure at the inlets of two microfluidic geometries, we have shown stability of our device to within ±1% of the set point using a PID control method and within ±5% of the set point using a bang-bang control method with response times of less than 1 second. This device offers a low-cost option to drive and control well-regulated pressure-driven flow through microfluidic chips.

Microfluidic size separation of cells and particles using a swinging bucket centrifuge

PubMed Central

Yeo, Joo Chuan; Wang, Zhiping; Lim, Chwee Teck

2015-01-01

Biomolecular separation is crucial for downstream analysis. Separation technique mainly relies on centrifugal sedimentation. However, minuscule sample volume separation and extraction is difficult with conventional centrifuge. Furthermore, conventional centrifuge requires density gradient centrifugation which is laborious and time-consuming. To overcome this challenge, we present a novel size-selective bioparticles separation microfluidic chip on a swinging bucket minifuge. Size separation is achieved using passive pressure driven centrifugal fluid flows coupled with centrifugal force acting on the particles within the microfluidic chip. By adopting centrifugal microfluidics on a swinging bucket rotor, we achieved over 95% efficiency in separating mixed 20 μm and 2 μm colloidal dispersions from its liquid medium. Furthermore, by manipulating the hydrodynamic resistance, we performed size separation of mixed microbeads, achieving size efficiency of up to 90%. To further validate our device utility, we loaded spiked whole blood with MCF-7 cells into our microfluidic device and subjected it to centrifugal force for a mere duration of 10 s, thereby achieving a separation efficiency of over 75%. Overall, our centrifugal microfluidic device enables extremely rapid and label-free enrichment of different sized cells and particles with high efficiency. PMID:26487900

Predicting the behavior of microfluidic circuits made from discrete elements

PubMed Central

Bhargava, Krisna C.; Thompson, Bryant; Iqbal, Danish; Malmstadt, Noah

2015-01-01

Microfluidic devices can be used to execute a variety of continuous flow analytical and synthetic chemistry protocols with a great degree of precision. The growing availability of additive manufacturing has enabled the design of microfluidic devices with new functionality and complexity. However, these devices are prone to larger manufacturing variation than is typical of those made with micromachining or soft lithography. In this report, we demonstrate a design-for-manufacturing workflow that addresses performance variation at the microfluidic element and circuit level, in context of mass-manufacturing and additive manufacturing. Our approach relies on discrete microfluidic elements that are characterized by their terminal hydraulic resistance and associated tolerance. Network analysis is employed to construct simple analytical design rules for model microfluidic circuits. Monte Carlo analysis is employed at both the individual element and circuit level to establish expected performance metrics for several specific circuit configurations. A protocol based on osmometry is used to experimentally probe mixing behavior in circuits in order to validate these approaches. The overall workflow is applied to two application circuits with immediate use at on the bench-top: series and parallel mixing circuits that are modularly programmable, virtually predictable, highly precise, and operable by hand. PMID:26516059

Low-cost feedback-controlled syringe pressure pumps for microfluidics applications

PubMed Central

Lake, John R.; Heyde, Keith C.

2017-01-01

Microfluidics are widely used in research ranging from bioengineering and biomedical disciplines to chemistry and nanotechnology. As such, there are a large number of options for the devices used to drive and control flow through microfluidic channels. Commercially available syringe pumps are probably the most commonly used instruments for this purpose, but are relatively high-cost and have inherent limitations due to their flow profiles when they are run open-loop. Here, we present a low-cost ($110) syringe pressure pump that uses feedback control to regulate the pressure into microfluidic chips. Using an open-source microcontroller board (Arduino), we demonstrate an easily operated and programmable syringe pump that can be run using either a PID or bang-bang control method. Through feedback control of the pressure at the inlets of two microfluidic geometries, we have shown stability of our device to within ±1% of the set point using a PID control method and within ±5% of the set point using a bang-bang control method with response times of less than 1 second. This device offers a low-cost option to drive and control well-regulated pressure-driven flow through microfluidic chips. PMID:28369134

Cost Effective Paper-Based Colorimetric Microfluidic Devices and Mobile Phone Camera Readers for the Classroom

ERIC Educational Resources Information Center

Koesdjojo, Myra T.; Pengpumkiat, Sumate; Wu, Yuanyuan; Boonloed, Anukul; Huynh, Daniel; Remcho, Thomas P.; Remcho, Vincent T.

2015-01-01

We have developed a simple and direct method to fabricate paper-based microfluidic devices that can be used for a wide range of colorimetric assay applications. With these devices, assays can be performed within minutes to allow for quantitative colorimetric analysis by use of a widely accessible iPhone camera and an RGB color reader application…

Geometrical effect characterization of femtosecond-laser manufactured glass microfluidic chips based on optical manipulation of submicroparticles

NASA Astrophysics Data System (ADS)

Kotsifaki, Domna G.; Mackenzie, Mark D.; Polydefki, Georgia; Kar, Ajoy K.; Makropoulou, Mersini; Serafetinides, Alexandros A.

2017-12-01

Microfluidic devices provide a platform with wide ranging applications from environmental monitoring to disease diagnosis. They offer substantive advantages but are often not optimized or designed to be used by nonexpert researchers. Microchannels of a microanalysis platform and their geometrical characterization are of eminent importance when designing such devices. We present a method that is used to optimize each microchannel within a device using high-throughput particle manipulation. For this purpose, glass-based microfluidic devices, with three-dimensional channel networks of several geometrical sizes, were fabricated by employing laser fabrication techniques. The effect of channel geometry was investigated by employing an optical tweezer. The optical trapping force depends on the flow velocity that is associated with the dimensions of the microchannel. We observe a linear dependence of the trapping efficiency and of the fluid flow velocity, with the channel dimensions. We determined that the highest trapping efficiency was achieved for microchannels with aspect ratio equal to one. Numerical simulation validated the impact of the device design dimensions on the trapping efficiency. This investigation indicates that the geometrical characteristics, the flow velocity, and trapping efficiency are crucial and should be considered when fabricating microfluidic devices for cell studies.

High-pressure microfluidic control in lab-on-a-chip devices using mobile polymer monoliths.

PubMed

Hasselbrink, Ernest F; Shepodd, Timothy J; Rehm, Jason E

2002-10-01

We have developed a nonstick polymer formulation for creating moving parts inside of microfluidic channels and have applied the technique to create piston-based devices that overcome several microfluidic flow control challenges. The parts were created bycompletely filling the channels of a glass microfluidic chip with the monomer/ solvent/initiator components of a nonstick photopolymer and then selectively exposing the chip to UV light in order to define mobile pistons (or other quasi-two-dimensional shapes) inside the channels. Stops defined in the substrate prevent the part from flushing out of the device but also provide sealing surfaces so that valves and other flow control devices are possible. Sealing against pressures greater than 30 MPa (4,500 psi) and actuation times less than 33 ms are observed. An on-chip check valve, a diverter valve, and a 10-nL pipet are demonstrated. This valving technology, coupled with high-pressure electrokinetic pumps, should make it possible to create a completely integrated HPLC system on a chip.

Microfluidic devices to enrich and isolate circulating tumor cells

PubMed Central

Myung, J. H.; Hong, S.

2015-01-01

Given the potential clinical impact of circulating tumor cells (CTCs) in blood as a clinical biomarker for diagnosis and prognosis of various cancers, a myriad of detection methods for CTCs have been recently introduced. Among those, a series of microfluidic devices are particularly promising as these uniquely offer micro-scale analytical systems that are highlighted by low consumption of samples and reagents, high flexibility to accommodate other cutting-edge technologies, precise and well-defined flow behaviors, and automation capability, presenting significant advantages over the conventional larger scale systems. In this review, we highlight the advantages of microfluidic devices and their translational potential into CTC detection methods, categorized by miniaturization of bench-top analytical instruments, integration capability with nanotechnologies, and in situ or sequential analysis of captured CTCs. This review provides a comprehensive overview of recent advances in the CTC detection achieved through application of microfluidic devices and their challenges that these promising technologies must overcome to be clinically impactful. PMID:26549749

Fabrication and optimisation of a fused filament 3D-printed microfluidic platform

NASA Astrophysics Data System (ADS)

Tothill, A. M.; Partridge, M.; James, S. W.; Tatam, R. P.

2017-03-01

A 3D-printed microfluidic device was designed and manufactured using a low cost (2000) consumer grade fusion deposition modelling (FDM) 3D printer. FDM printers are not typically used, or are capable, of producing the fine detailed structures required for microfluidic fabrication. However, in this work, the optical transparency of the device was improved through manufacture optimisation to such a point that optical colorimetric assays can be performed in a 50 µl device. A colorimetric enzymatic cascade assay was optimised using glucose oxidase and horseradish peroxidase for the oxidative coupling of aminoantipyrine and chromotropic acid to produce a blue quinoneimine dye with a broad absorbance peaking at 590 nm for the quantification of glucose in solution. For comparison the assay was run in standard 96 well plates with a commercial plate reader. The results show the accurate and reproducible quantification of 0-10 mM glucose solution using a 3D-printed microfluidic optical device with performance comparable to that of a plate reader assay.

Electrowetting on plasma-deposited fluorocarbon hydrophobic films for biofluid transport in microfluidics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bayiati, P.; Tserepi, A.; Petrou, P. S.

2007-05-15

The present work focuses on the plasma deposition of fluorocarbon (FC) films on surfaces and the electrostatic control of their wettability (electrowetting). Such films can be employed for actuation of fluid transport in microfluidic devices, when deposited over patterned electrodes. Here, the deposition was performed using C{sub 4}F{sub 8} and the plasma parameters that permit the creation of films with optimized properties desirable for electrowetting were established. The wettability of the plasma-deposited surfaces was characterized by means of contact angle measurements (in the static and dynamic mode). The thickness of the deposited films was probed in situ by means ofmore » spectroscopic ellipsometry, while the surface roughness was provided by atomic force microscopy. These plasma-deposited FC films in combination with silicon nitride, a material of high dielectric constant, were used to create a dielectric structure that requires reduced voltages for successful electrowetting. Electrowetting experiments using protein solutions were conducted on such optimized dielectric structures and were compared with similar structures bearing commercial spin-coated Teflon registered amorphous fluoropolymer (AF) film as the hydrophobic top layer. Our results show that plasma-deposited FC films have desirable electrowetting behavior and minimal protein adsorption, a requirement for successful transport of biological solutions in 'digital' microfluidics.« less

A compact model for electroosmotic flows in microfluidic devices

NASA Astrophysics Data System (ADS)

Qiao, R.; Aluru, N. R.

2002-09-01

A compact model to compute flow rate and pressure in microfluidic devices is presented. The microfluidic flow can be driven by either an applied electric field or a combined electric field and pressure gradient. A step change in the ζ-potential on a channel wall is treated by a pressure source in the compact model. The pressure source is obtained from the pressure Poisson equation and conservation of mass principle. In the proposed compact model, the complex fluidic network is simplified by an electrical circuit. The compact model can predict the flow rate, pressure distribution and other basic characteristics in microfluidic channels quickly with good accuracy when compared to detailed numerical simulation. Using the compact model, fluidic mixing and dispersion control are studied in a complex microfluidic network.

Three-dimensional ordered titanium dioxide-zirconium dioxide film-based microfluidic device for efficient on-chip phosphopeptide enrichment.

PubMed

Zhao, De; He, Zhongyuan; Wang, Gang; Wang, Hongzhi; Zhang, Qinghong; Li, Yaogang

2016-09-15

Microfluidic technology plays a significant role in separating biomolecules, because of its miniaturization, integration, and automation. Introducing micro/nanostructured functional materials can improve the properties of microfluidic devices, and extend their application. Inverse opal has a three-dimensional ordered net-like structure. It possesses a large surface area and exhibits good mass transport, making it a good candidate for bio-separation. This study exploits inverse opal titanium dioxide-zirconium dioxide films for on-chip phosphopeptide enrichment. Titanium dioxide-zirconium dioxide inverse opal film-based microfluidic devices were constructed from templates of 270-, 340-, and 370-nm-diameter poly(methylmethacrylate) spheres. The phosphopeptide enrichments of these devices were determined by matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry. The device constructed from the 270-nm-diameter sphere template exhibited good comprehensive phosphopeptide enrichment, and was the best among these three devices. Because the size of opal template used in construction was the smallest, the inverse opal film therefore had the smallest pore sizes and the largest surface area. Enrichment by this device was also better than those of similar devices based on nanoparticle films and single component films. The titanium dioxide-zirconium dioxide inverse opal film-based device provides a promising approach for the efficient separation of various biomolecules. Copyright © 2016 Elsevier Inc. All rights reserved.

Methods and Devices for Micro-Isolation, Extraction, and/or Analysis of Microscale Components

NASA Technical Reports Server (NTRS)

Wade, Lawrence A. (Inventor); Kartalov, Emil P. (Inventor); Taylor, Clive (Inventor); Shibata, Darryl (Inventor)

2014-01-01

Provided herein are devices and methods for the micro-isolation of biological cellular material. A micro-isolation apparatus described can comprise a photomask that protects regions of interest against DNA-destroying illumination. The micro-isolation apparatus can further comprise photosensitive material defining access wells following illumination and subsequent developing of the photosensitive material. The micro-isolation apparatus can further comprise a chambered microfluidic device comprising channels providing access to wells defined in photosensitive material. The micro-isolation apparatus can comprise a chambered microfluidic device without access wells defined in photosensitive material where valves control the flow of gases or liquids through the channels of the microfluidic device. Also included are methods for selectively isolating cellular material using the apparatuses described herein, as are methods for biochemical analysis of individual regions of interest of cellular material using the devices described herein. Further included are methods of making masking arrays useful for the methods described herein.

Stochastic Model of Clogging in a Microfluidic Cell Sorter

NASA Astrophysics Data System (ADS)

Fai, Thomas; Rycroft, Chris

2016-11-01

Microfluidic devices for sorting cells by deformability show promise for various medical purposes, e.g. detecting sickle cell anemia and circulating tumor cells. One class of such devices consists of a two-dimensional array of narrow channels, each column containing several identical channels in parallel. Cells are driven through the device by an applied pressure or flow rate. Such devices allows for many cells to be sorted simultaneously, but cells eventually clog individual channels and change the device properties in an unpredictable manner. In this talk, we propose a stochastic model for the failure of such microfluidic devices by clogging and present preliminary theoretical and computational results. The model can be recast as an ODE that exhibits finite time blow-up under certain conditions. The failure time distribution is investigated analytically in certain limiting cases, and more realistic versions of the model are solved by computer simulation.

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

PubMed

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

2016-03-21

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

Novel Developments of Mobile Sensing Based on the Integration of Microfluidic Devices and Smartphone

PubMed Central

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

2016-01-01

Portable electronic devices and wireless communication systems enable a broad range of applications such as environmental and food safety monitoring, personalized medicine and healthcare management. Particularly, hybrid smartphone and microfluidic devices provide an integrated solution for the new generation of mobile sensing applications. Such mobile sensing based on microfluidic devices (broadly defined) and smartphones (MS2) offers a mobile laboratory for performing a wide range of bio-chemical detection and analysis functions such as water and food quality analysis, routine health tests and disease diagnosis. MS2 offers significant advantages over traditional platforms in terms of test speed and control, low cost, mobility, ease-of-operation and data management. These improvements put MS2 in a promising position in the fields of interdisciplinary basic and applied research. In particular, MS2 enables applications to remote infield testing, homecare, and healthcare in low-resource areas. The marriage of smartphones and microfluidic devices offers a powerful on-chip operating platform to enable various bio-chemical tests, remote sensing, data analysis and management in a mobile fashion. The implications of such integration are beyond telecommunication and microfluidic-related research and technology development. In this review, we will first provide the general background of microfluidic-based sensing, smartphone-based sensing, and their integration. Then, we will focus on several key application areas of MS2 by systematically reviewing the important literature in each area. We will conclude by discussing our perspectives on the opportunities, issues and future directions of this emerging novel field. PMID:26899264

Digital Microfluidics for Manipulation and Analysis of a Single Cell.

PubMed

He, Jie-Long; Chen, An-Te; Lee, Jyong-Huei; Fan, Shih-Kang

2015-09-15

The basic structural and functional unit of a living organism is a single cell. To understand the variability and to improve the biomedical requirement of a single cell, its analysis has become a key technique in biological and biomedical research. With a physical boundary of microchannels and microstructures, single cells are efficiently captured and analyzed, whereas electric forces sort and position single cells. Various microfluidic techniques have been exploited to manipulate single cells through hydrodynamic and electric forces. Digital microfluidics (DMF), the manipulation of individual droplets holding minute reagents and cells of interest by electric forces, has received more attention recently. Because of ease of fabrication, compactness and prospective automation, DMF has become a powerful approach for biological application. We review recent developments of various microfluidic chips for analysis of a single cell and for efficient genetic screening. In addition, perspectives to develop analysis of single cells based on DMF and emerging functionality with high throughput are discussed.

Digital Microfluidics for Manipulation and Analysis of a Single Cell

PubMed Central

He, Jie-Long; Chen, An-Te; Lee, Jyong-Huei; Fan, Shih-Kang

2015-01-01

The basic structural and functional unit of a living organism is a single cell. To understand the variability and to improve the biomedical requirement of a single cell, its analysis has become a key technique in biological and biomedical research. With a physical boundary of microchannels and microstructures, single cells are efficiently captured and analyzed, whereas electric forces sort and position single cells. Various microfluidic techniques have been exploited to manipulate single cells through hydrodynamic and electric forces. Digital microfluidics (DMF), the manipulation of individual droplets holding minute reagents and cells of interest by electric forces, has received more attention recently. Because of ease of fabrication, compactness and prospective automation, DMF has become a powerful approach for biological application. We review recent developments of various microfluidic chips for analysis of a single cell and for efficient genetic screening. In addition, perspectives to develop analysis of single cells based on DMF and emerging functionality with high throughput are discussed. PMID:26389890

Experimental Microfluidic System

NASA Technical Reports Server (NTRS)

Culbertson, Christopher; Gonda, Steve; Ramsey, John Michael

2005-01-01

The ultimate goal of this project is to integrate microfluidic devices with NASA's space bioreactor systems. In such a system, the microfluidic device would provide realtime feedback control of the bioreactor by monitoring pH, glucose, and lactate levels in the cell media; and would provide an analytical capability to the bioreactor in exterrestrial environments for monitoring bioengineered cell products and health changes in cells due to environmental stressors. Such integrated systems could be used as biosentinels both in space and on planet surfaces. The objective is to demonstrate the ability of microfabricated devices to repeatedly and reproducibly perform bead cytometry experiments in micro, lunar, martian, and hypergravity (1.8g).

Micro-Fluidic Device for Drug Delivery

NASA Technical Reports Server (NTRS)

Beebe, David J. (Inventor); Eddington, David T. (Inventor); MacDonald, Michael J. (Inventor); Mensing, Glennys A. (Inventor)

2014-01-01

A microfluidic device is provided for delivering a drug to an individual. The microfluidic device includes a body that defines a reservoir for receiving the drug therein. A valve interconnects the reservoir to an output needle that is insertable into the skin of an individual. A pressure source urges the drug from the reservoir toward the needle. The valve is movable between a closed position preventing the flow of the drug from the reservoir to the output needle and an open position allowing for the flow of the drug from the reservoir to the output needle in response to a predetermined condition in the physiological fluids of the individual.

Microfluidic device for drug delivery

NASA Technical Reports Server (NTRS)

MacDonald, Michael J. (Inventor); Eddington, David T. (Inventor); Beebe, David J. (Inventor); Mensing, Glennys A. (Inventor)

2010-01-01

A microfluidic device is provided for delivering a drug to an individual. The microfluidic device includes a body that defines a reservoir for receiving the drug therein. A valve interconnects the reservoir to an output needle that is insertable into the skin of an individual. A pressure source urges the drug from the reservoir toward the needle. The valve is movable between a closed position preventing the flow of the drug from the reservoir to the output needle and an open position allowing for the flow of the drug from the reservoir to the output needle in response to a predetermined condition in the physiological fluids of the individual.

Irreversible, direct bonding of nanoporous polymer membranes to PDMS or glass microdevices.

PubMed

Aran, Kiana; Sasso, Lawrence A; Kamdar, Neal; Zahn, Jeffrey D

2010-03-07

A method for integrating porous polymer membranes such as polycarbonate, polyethersulfone and polyethylene terephthalate to microfluidic devices is described. The use of 3-aminopropyltriethoxysilane as a chemical crosslinking agent was extended to integrate membranes with PDMS and glass microfluidic channels. A strong, irreversible bond between the membranes and microfluidic structure was achieved. The bonding strength in the APTES treated devices was significantly greater than in devices fabricated using either a PDMS "glue" or two-part epoxy bonding method. Evaluation of a filtering microdevice and the pore structure via SEM indicates the APTES conjugation does not significantly alter the membrane transport function and pore morphology.

A microfluidic platform for chemical stimulation and real time analysis of catecholamine secretion from neuroendocrine cells.

PubMed

Ges, Igor A; Brindley, Rebecca L; Currie, Kevin P M; Baudenbacher, Franz J

2013-12-07

Release of neurotransmitters and hormones by calcium-regulated exocytosis is a fundamental cellular process that is disrupted in a variety of psychiatric, neurological, and endocrine disorders. As such, there is significant interest in targeting neurosecretion for drug and therapeutic development, efforts that will be aided by novel analytical tools and devices that provide mechanistic insight coupled with increased experimental throughput. Here, we report a simple, inexpensive, reusable, microfluidic device designed to analyze catecholamine secretion from small populations of adrenal chromaffin cells in real time, an important neuroendocrine component of the sympathetic nervous system and versatile neurosecretory model. The device is fabricated by replica molding of polydimethylsiloxane (PDMS) using patterned photoresist on silicon wafer as the master. Microfluidic inlet channels lead to an array of U-shaped "cell traps", each capable of immobilizing single or small groups of chromaffin cells. The bottom of the device is a glass slide with patterned thin film platinum electrodes used for electrochemical detection of catecholamines in real time. We demonstrate reliable loading of the device with small populations of chromaffin cells, and perfusion/repetitive stimulation with physiologically relevant secretagogues (carbachol, PACAP, KCl) using the microfluidic network. Evoked catecholamine secretion was reproducible over multiple rounds of stimulation, and graded as expected to different concentrations of secretagogue or removal of extracellular calcium. Overall, we show this microfluidic device can be used to implement complex stimulation paradigms and analyze the amount and kinetics of catecholamine secretion from small populations of neuroendocrine cells in real time.

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

NASA Astrophysics Data System (ADS)

Liu, Robin H.; Grodzinski, Piotr

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

3D-PRINTING OF TRANSPARENT BIO-MICROFLUIDIC DEVICES IN PEG-DA

PubMed Central

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

2016-01-01

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

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

PubMed

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

2013-03-01

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

An electric stimulation system for electrokinetic particle manipulation in microfluidic devices

NASA Astrophysics Data System (ADS)

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

2013-03-01

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

Generating Electric Fields in PDMS Microfluidic Devices with Salt Water Electrodes

PubMed Central

Sciambi, Adam; Abate, Adam R.

2014-01-01

Droplet merging and sorting in microfluidic devices usually rely on electric fields generated by solid metal electrodes. We show that simpler and more reliable salt water electrodes, despite their lower conductivity, can perform the same droplet manipulations at the same voltages. PMID:24671446

Thermal Blood Clot Formation and use in Microfluidic Device Valving Applications

NASA Technical Reports Server (NTRS)

Tai, Yu-Chong (Inventor); Shi, Wendian (Inventor); Guo, Luke (Inventor)

2014-01-01

The present invention provides a method of forming a blood-clot microvalve by heating blood in a capillary tube of a microfluidic device. Also described are methods of modulating liquid flow in a capillary tube by forming and removing a blood-clot microvalve.

Modelling of capillary-driven flow for closed paper-based microfluidic channels

NASA Astrophysics Data System (ADS)

Songok, Joel; Toivakka, Martti

2017-06-01

Paper-based microfluidics is an emerging field focused on creating inexpensive devices, with simple fabrication methods for applications in various fields including healthcare, environmental monitoring and veterinary medicine. Understanding the flow of liquid is important in achieving consistent operation of the devices. This paper proposes capillary models to predict flow in paper-based microfluidic channels, which include a flow accelerating hydrophobic top cover. The models, which consider both non-absorbing and absorbing substrates, are in good agreement with the experimental results.

Lagrangian 3D tracking of fluorescent microscopic objects in motion

NASA Astrophysics Data System (ADS)

Darnige, T.; Figueroa-Morales, N.; Bohec, P.; Lindner, A.; Clément, E.

2017-05-01

We describe the development of a tracking device, mounted on an epi-fluorescent inverted microscope, suited to obtain time resolved 3D Lagrangian tracks of fluorescent passive or active micro-objects in microfluidic devices. The system is based on real-time image processing, determining the displacement of a x, y mechanical stage to keep the chosen object at a fixed position in the observation frame. The z displacement is based on the refocusing of the fluorescent object determining the displacement of a piezo mover keeping the moving object in focus. Track coordinates of the object with respect to the microfluidic device as well as images of the object are obtained at a frequency of several tenths of Hertz. This device is particularly well adapted to obtain trajectories of motile micro-organisms in microfluidic devices with or without flow.

Lagrangian 3D tracking of fluorescent microscopic objects in motion.

PubMed

Darnige, T; Figueroa-Morales, N; Bohec, P; Lindner, A; Clément, E

2017-05-01

We describe the development of a tracking device, mounted on an epi-fluorescent inverted microscope, suited to obtain time resolved 3D Lagrangian tracks of fluorescent passive or active micro-objects in microfluidic devices. The system is based on real-time image processing, determining the displacement of a x, y mechanical stage to keep the chosen object at a fixed position in the observation frame. The z displacement is based on the refocusing of the fluorescent object determining the displacement of a piezo mover keeping the moving object in focus. Track coordinates of the object with respect to the microfluidic device as well as images of the object are obtained at a frequency of several tenths of Hertz. This device is particularly well adapted to obtain trajectories of motile micro-organisms in microfluidic devices with or without flow.

Microfluidic tools for cell biological research

PubMed Central

Velve-Casquillas, Guilhem; Le Berre, Maël; Piel, Matthieu; Tran, Phong T.

2010-01-01

Summary Microfluidic technology is creating powerful tools for cell biologists to control the complete cellular microenvironment, leading to new questions and new discoveries. We review here the basic concepts and methodologies in designing microfluidic devices, and their diverse cell biological applications. PMID:21152269

Versatile fabrication of paper-based microfluidic devices with high chemical resistance using scholar glue and magnetic masks.

PubMed

Cardoso, Thiago M G; de Souza, Fabrício R; Garcia, Paulo T; Rabelo, Denilson; Henry, Charles S; Coltro, Wendell K T

2017-06-29

Simple methods have been developed for fabricating microfluidic paper-based analytical devices (μPADs) but few of these devices can be used with organic solvents and/or aqueous solutions containing surfactants. This study describes a simple fabrication strategy for μPADs that uses readily available scholar glue to create the hydrophobic flow barriers that are resistant to surfactants and organic solvents. Microfluidic structures were defined by magnetic masks designed with either neodymium magnets or magnetic sheets to define the patter, and structures were created by spraying an aqueous solution of glue on the paper surface. The glue-coated paper was then exposed to UV/Vis light for cross-linking to maximize chemical resistance. Examples of microzone arrays and microfluidic devices are demonstrated. μPADs fabricated with scholar glue retained their barriers when used with surfactants, organic solvents, and strong/weak acids and bases unlike common wax-printed barriers. Paper microzones and microfluidic devices were successfully used for colorimetric assays of clinically relevant analytes commonly detected in urinalysis to demonstrate the low background of the barrier material and generally applicability to sensing. The proposed fabrication method is attractive for both its ability to be used with diverse chemistries and the low cost and simplicity of the materials and process. Copyright © 2017 Elsevier B.V. All rights reserved.

Chemical vapor deposition of aminopropyl silanes in microfluidic channels for highly efficient microchip capillary electrophoresis-electrospray ionization-mass spectrometry.

PubMed

Batz, Nicholas G; Mellors, J Scott; Alarie, Jean Pierre; Ramsey, J Michael

2014-04-01

We describe a chemical vapor deposition (CVD) method for the surface modification of glass microfluidic devices designed to perform electrophoretic separations of cationic species. The microfluidic channel surfaces were modified using aminopropyl silane reagents. Coating homogeneity was inferred by precise measurement of the separation efficiency and electroosmotic mobility for multiple microfluidic devices. Devices coated with (3-aminopropyl)di-isopropylethoxysilane (APDIPES) yielded near diffusion-limited separations and exhibited little change in electroosmotic mobility between pH 2.8 and pH 7.5. We further evaluated the temporal stability of both APDIPES and (3-aminopropyl)triethoxysilane (APTES) coatings when stored for a total of 1 week under vacuum at 4 °C or filled with pH 2.8 background electrolyte at room temperature. Measurements of electroosmotic flow (EOF) and separation efficiency during this time confirmed that both coatings were stable under both conditions. Microfluidic devices with a 23 cm long, serpentine electrophoretic separation channel and integrated nanoelectrospray ionization emitter were CVD coated with APDIPES and used for capillary electrophoresis (CE)-electrospray ionization (ESI)-mass spectrometry (MS) of peptides and proteins. Peptide separations were fast and highly efficient, yielding theoretical plate counts over 600,000 and a peak capacity of 64 in less than 90 s. Intact protein separations using these devices yielded Gaussian peak profiles with separation efficiencies between 100,000 and 400,000 theoretical plates.

Integrated electrokinetically driven microfluidic devices with pH-mediated solid-phase extraction coupled to microchip electrophoresis for preterm birth biomarkers.

PubMed

Sonker, Mukul; Knob, Radim; Sahore, Vishal; Woolley, Adam T

2017-07-01

Integration in microfluidics is important for achieving automation. Sample preconcentration integrated with separation in a microfluidic setup can have a substantial impact on rapid analysis of low-abundance disease biomarkers. Here, we have developed a microfluidic device that uses pH-mediated solid-phase extraction (SPE) for the enrichment and elution of preterm birth (PTB) biomarkers. Furthermore, this SPE module was integrated with microchip electrophoresis for combined enrichment and separation of multiple analytes, including a PTB peptide biomarker (P1). A reversed-phase octyl methacrylate monolith was polymerized as the SPE medium in polyethylene glycol diacrylate modified cyclic olefin copolymer microfluidic channels. Eluent for pH-mediated SPE of PTB biomarkers on the monolith was optimized using different pH values and ionic concentrations. Nearly 50-fold enrichment was observed in single channel SPE devices for a low nanomolar solution of P1, with great elution time reproducibility (<7% RSD). The monolith binding capacity was determined to be 400 pg (0.2 pmol). A mixture of a model peptide (FA) and a PTB biomarker (P1) was extracted, eluted, injected, and then separated by microchip electrophoresis in our integrated device with ∼15-fold enrichment. This device shows important progress towards an integrated electrokinetically operated platform for preconcentration and separation of biomarkers. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A self-loading microfluidic device for determining the minimum inhibitory concentration of antibiotics.

PubMed

Cira, Nate J; Ho, Jack Y; Dueck, Megan E; Weibel, Douglas B

2012-03-21

This article describes a portable microfluidic technology for determining the minimum inhibitory concentration (MIC) of antibiotics against bacteria. The microfluidic platform consists of a set of chambers molded in poly(dimethylsiloxane) (PDMS) that are preloaded with antibiotic, dried, and reversibly sealed to a second layer of PDMS containing channels that connect the chambers. The assembled device is degassed via vacuum prior to its use, and the absorption of gas by PDMS provides the mechanism for actuating and metering the flow of fluid in the microfluidic channels and chambers. During the operation of the device, degas driven flow introduces a suspension of bacterial cells, dissolves the antibiotic, and isolates cells in individual chambers without cross contamination. The growth of bacteria in the chambers in the presence of a pH indicator produces a colorimetric change that can be detected visually using ambient light. Using this device we measured the MIC of vancomycin, tetracycline, and kanamycin against Enterococcus faecalis 1131, Proteus mirabilis HI4320, Klebsiella pneumoniae, and Escherichia coli MG1655 and report values that are comparable to standard liquid broth dilution measurements. The device provides a simple method for MIC determination of individual antibiotics against human pathogens that will have applications for clinical and point-of-care medicine. Importantly, this device is designed around simplicity: it requires a single pipetting step to introduce the sample, no additional components or external equipment for its operation, and provides a straightforward visual measurement of cell growth. As the device introduces a novel approach for filling and isolating dead-end microfluidic chambers that does not require valves and actuators, this technology should find applications in other portable assays and devices.

A Microfluidics-based Pulpal Arteriole Blood Flow Phantom for Validation of Doppler Ultrasound Devices in Pulpal Blood Flow Velocity Measurement.

PubMed

Kim, Dohyun; Park, Sung-Ho

2016-11-01

Recently, Doppler ultrasound has been used for the measurement of pulpal blood flow in human teeth. However, the reliability of this method has not been verified. In this study, we developed a model to simulate arteriole blood flow within the dental pulp by using microfluidics. This arteriole simulator, or flow phantom, was used to determine the reliability of measurements obtained by using a Doppler ultrasound device. A microfluidic chip was fabricated by using the soft lithography technique, and blood-mimicking fluid was pumped through the channel by a microfluidic system. A Doppler ultrasound device was used for the measurement of flow velocity. The peak, mean, and minimal flow velocities obtained from the phantom and the Doppler ultrasound device were compared by using linear regression analysis and Pearson correlation coefficient. Bland-Altman analyses were performed to evaluate the velocity differences between the flow generated by the phantom and the flow measurements made with the Doppler ultrasound device. The microfluidic system was able to generate the flow profiles as intended, and the fluid flow could be monitored and controlled by the software program. There were excellent linear correlations between the peak, mean, and minimal flow velocities of the phantom and those of the Doppler ultrasound device (r = 0.94-0.996, P < .001). However, the velocities were overestimated by the Doppler ultrasound device. This phantom provides opportunities for research and education involving the Doppler ultrasound technique in dentistry. Although Doppler ultrasound can be an effective tool for the measurement of pulpal blood flow velocity, it is essential to validate and calibrate the device before clinical use. Copyright © 2016 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

A microfluidic device for 2D to 3D and 3D to 3D cell navigation

NASA Astrophysics Data System (ADS)

Shamloo, Amir; Amirifar, Leyla

2016-01-01

Microfluidic devices have received wide attention and shown great potential in the field of tissue engineering and regenerative medicine. Investigating cell response to various stimulations is much more accurate and comprehensive with the aid of microfluidic devices. In this study, we introduced a microfluidic device by which the matrix density as a mechanical property and the concentration profile of a biochemical factor as a chemical property could be altered. Our microfluidic device has a cell tank and a cell culture chamber to mimic both 2D to 3D and 3D to 3D migration of three types of cells. Fluid shear stress is negligible on the cells and a stable concentration gradient can be obtained by diffusion. The device was designed by a numerical simulation so that the uniformity of the concentration gradients throughout the cell culture chamber was obtained. Adult neural cells were cultured within this device and they showed different branching and axonal navigation phenotypes within varying nerve growth factor (NGF) concentration profiles. Neural stem cells were also cultured within varying collagen matrix densities while exposed to NGF concentrations and they experienced 3D to 3D collective migration. By generating vascular endothelial growth factor concentration gradients, adult human dermal microvascular endothelial cells also migrated in a 2D to 3D manner and formed a stable lumen within a specific collagen matrix density. It was observed that a minimum absolute concentration and concentration gradient were required to stimulate migration of all types of the cells. This device has the advantage of changing multiple parameters simultaneously and is expected to have wide applicability in cell studies.

Fabrication of Three-dimensional Paper-based Microfluidic Devices for Immunoassays.

PubMed

Fernandes, Syrena C; Wilson, Daniel J; Mace, Charles R

2017-03-09

Paper wicks fluids autonomously due to capillary action. By patterning paper with hydrophobic barriers, the transport of fluids can be controlled and directed within a layer of paper. Moreover, stacking multiple layers of patterned paper creates sophisticated three-dimensional microfluidic networks that can support the development of analytical and bioanalytical assays. Paper-based microfluidic devices are inexpensive, portable, easy to use, and require no external equipment to operate. As a result, they hold great promise as a platform for point-of-care diagnostics. In order to properly evaluate the utility and analytical performance of paper-based devices, suitable methods must be developed to ensure their manufacture is reproducible and at a scale that is appropriate for laboratory settings. In this manuscript, a method to fabricate a general device architecture that can be used for paper-based immunoassays is described. We use a form of additive manufacturing (multi-layer lamination) to prepare devices that comprise multiple layers of patterned paper and patterned adhesive. In addition to demonstrating the proper use of these three-dimensional paper-based microfluidic devices with an immunoassay for human chorionic gonadotropin (hCG), errors in the manufacturing process that may result in device failures are discussed. We expect this approach to manufacturing paper-based devices will find broad utility in the development of analytical applications designed specifically for limited-resource settings.

A Two-Stage Microfluidic Device for the Isolation and Capture of Circulating Tumor Cells

NASA Astrophysics Data System (ADS)

Cook, Andrew; Belsare, Sayali; Giorgio, Todd; Mu, Richard

2014-11-01

Analysis of circulating tumor cells (CTCs) can be critical for studying how tumors grow and metastasize, in addition to personalizing treatment for cancer patients. CTCs are rare events in blood, making it difficult to remove CTCs from the blood stream. Two microfluidic devices have been developed to separate CTCs from blood. The first is a double spiral device that focuses cells into streams, the positions of which are determined by cell diameter. The second device uses ligand-coated magnetic nanoparticles that selectively attach to CTCs. The nanoparticles then pull CTCs out of solution using a magnetic field. These two devices will be combined into a single 2-stage microfluidic device that will capture CTCs more efficiently than either device on its own. The first stage depletes the number of blood cells in the sample by size-based separation. The second stage will magnetically remove CTCs from solution for study and culturing. Thus far, size-based separation has been achieved. Research will also focus on understanding the equations that govern fluid dynamics and magnetic fields in order to determine how the manipulation of microfluidic parameters, such as dimensions and flow rate, will affect integration and optimization of the 2-stage device. NSF-CREST: Center for Physics and Chemistry of Materials. HRD-0420516; Department of Defense, Peer Reviewed Medical Research Program Award W81XWH-13-1-0397.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Srivastava, Nimisha; Singh, Anup K

Microfluidic devices and methods for flow cytometry are described. In described examples, various sample handling and preparation steps may be carried out within a same microfluidic device as flow cytometry steps. A combination of imaging and flow cytometry is described. In some examples, spiral microchannels serve as incubation chambers. Examples of automated sample handling and flow cytometry are described.

Systems, devices, and methods for agglutination assays using sedimentation

DOEpatents

Schaff, Ulrich Y.; Sommer, Gregory J.; Singh, Anup K.

2016-01-26

Embodiments of the present invention include methods for conducting agglutination assays using sedimentation. Aggregates may be exposed to sedimentation forces and travel through a density medium to a detection area. Microfluidic devices, such as microfluidic disks, are described for conducting the agglutination assays, as are systems for conducting the assays.

Single nanopore transport of synthetic and biological polyelectrolytes in three-dimensional hybrid microfluidic/nanofluidic devices

DOE PAGES

King, Travis L.; Gatimu, Enid N.; Bohn, Paul W.

2009-01-02

This paper presents a study of electrokinetic transport in single nanopores integrated into vertically-stacked three-dimensional hybrid microfluidic/nanofluidic structures. In these devices single nanopores, created by focused ion beam (FIB) milling in thin polymer films, provide fluidic connection between two vertically separated, perpendicular microfluidic channels. Experiments address both systems in which the nanoporous membrane is composed of the same (homojunction) or different (heterojunction) polymer as the microfluidic channels. These devices are then used to study the electrokinetic transport properties of synthetic (i.e., polystyrene sulfonate and polyallylamine) and biological (i.e.,DNA) polyelectrolytes across these nanopores. Single nanopore transport of polyelectrolytes across these nanoporesmore » using both electrical current measurements and confocal microscopy. Both optical and electrical measurements indicate that electroosmotic transport is predominant over electrophoresis in single nanopores with d > 180 nm, consistent with results obtained under similar conditions for nanocapillary array membranes.« less

Compact handheld low-cost biosensor platform for remote health monitoring

NASA Astrophysics Data System (ADS)

Hastanin, J.; Lenaerts, C.; Gailly, P.; Jans, H.; Huang, C.; Lagae, L.; Kokkinos, D.; Fleury-Frenette, K.

2016-04-01

In this paper, we present an original concept of plasmonic-related instrumentation platform dedicated to diagnostic biosensing tests out of the laboratory. The developed instrumental platform includes both disposable one-use microfluidic affinity biochip and compact optical readout device for biochip monitoring involving mobile Internet devices for data processing and communication. The biochip includes both microfluidic and optical coupling structures formed into a single plastic slab. The microfluidic path of the biochip operates in passive capillary pumping mode. In the proof-of-concept prototype, we address specifically the sensing format involving Surface Plasmon Resonance phenomenon. The biochip is plugged in the readout device without the use of an index matching fluid. An essential advantage of the developed biochip is that its implementation involves conventional hot embossing and thin film deposition process, perfectly suited for mass production of low-cost microfluidic biochip for biochemical applications.

Compartmental culture of embryonic stem cell-derived neurons in microfluidic devices for use in axonal biology.

PubMed

Shin, Hwa Sung; Kim, Hyung Joon; Min, Seul Ki; Kim, Sung Hoon; Lee, Byung Man; Jeon, Noo Li

2010-08-01

Axonal pathology has been clearly implicated in neurodegenerative diseases making the compartmental culture of neurons a useful research tool. Primary neurons have already been cultured in compartmental microfluidic devices but their derivation from an animal is a time-consuming and difficult work and has a limit in their sources. Embryonic stem cell (ESC)-derived neurons (ESC_Ns) overcome this limit, since ESCs can be renewed without limit and can be differentiated into ESC_Ns by robust and reproducible protocols. In this research, ESC_Ns were derived from mouse ESCs in compartmental microfluidic devices, and their axons were isolated from the somal cell bodies. Once embryoid bodies (EBs) were localized in the microfluidic culture chamber, ESC_Ns spread out from the EBs and occupied the cell culture chamber. Their axons traversed the microchannels and finally were isolated from the somata, providing an arrangement comparable to dissociated primary neurons. This ESC_N compartmental microfluidic culture system not only offers a substitute for the primary neuron counterpart system but also makes it possible to make comparisons between the two systems.

Accurately tracking single-cell movement trajectories in microfluidic cell sorting devices.

PubMed

Jeong, Jenny; Frohberg, Nicholas J; Zhou, Enlu; Sulchek, Todd; Qiu, Peng

2018-01-01

Microfluidics are routinely used to study cellular properties, including the efficient quantification of single-cell biomechanics and label-free cell sorting based on the biomechanical properties, such as elasticity, viscosity, stiffness, and adhesion. Both quantification and sorting applications require optimal design of the microfluidic devices and mathematical modeling of the interactions between cells, fluid, and the channel of the device. As a first step toward building such a mathematical model, we collected video recordings of cells moving through a ridged microfluidic channel designed to compress and redirect cells according to cell biomechanics. We developed an efficient algorithm that automatically and accurately tracked the cell trajectories in the recordings. We tested the algorithm on recordings of cells with different stiffness, and showed the correlation between cell stiffness and the tracked trajectories. Moreover, the tracking algorithm successfully picked up subtle differences of cell motion when passing through consecutive ridges. The algorithm for accurately tracking cell trajectories paves the way for future efforts of modeling the flow, forces, and dynamics of cell properties in microfluidics applications.

Microfluidics @ the Beach: Introduction of Microfluidics Technology to the ChE Curriculum at Cal State Long Beach

ERIC Educational Resources Information Center

Lo, Roger C.; Bhatia, Hina; Venkatraman, Rahul; Jang, Larry K.

2015-01-01

Microfluidics involves the study of the behavior of fluids at microscale, fluid manipulations, and the design of the devices that can effectively perform such manipulations. We are developing two new elective courses to include microfluidics in our curriculum at CSULB. Herein, we present the results of the first course, Microfabrication and…

Current Trends in Ubiquitous Biosensing

DTIC Science & Technology

2013-08-01

fundamental advances have been made in the synergistic combination of research in the fields of microfluidics and optics, coined “optofluidics” [24-26...microfabrication and clean-room techniques for the development of microfluidic devices [27]. Advances in the rapid fabrication of nano- and microfluidic ...Transduction Microfluidic Processing Sample Introduction Optofluidics Enabled Bio-Sensing A B C Figure 4: (A) Schematic diagram of optofluidic tomography

A microfluidic tubing method and its application for controlled synthesis of polymeric nanoparticles.

PubMed

Wang, Jidong; Chen, Wenwen; Sun, Jiashu; Liu, Chao; Yin, Qifang; Zhang, Lu; Xianyu, Yunlei; Shi, Xinghua; Hu, Guoqing; Jiang, Xingyu

2014-05-21

This report describes a straightforward but robust tubing method for connecting polydimethylsiloxane (PDMS) microfluidic devices to external equipment. The interconnection is irreversible and can sustain a pressure of up to 4.5 MPa that is characterized experimentally and theoretically. To demonstrate applications of this high-pressure tubing technique, we fabricate a semicircular microfluidic channel to implement a high-throughput, size-controlled synthesis of poly(lactic-co-glycolic acid) (PLGA) nanoparticles ranging from 55 to 135 nm in diameter. This microfluidic device allows for a total flow rate of 410 mL h(-1), resulting in enhanced convective mixing which can be utilized to precipitate small size nanoparticles with a good dispersion. We expect that this tubing technique would be widely used in microfluidic chips for nanoparticle synthesis, cell manipulation, and potentially nanofluidic applications.

A PDMS/paper/glass hybrid microfluidic biochip integrated with aptamer-functionalized graphene oxide nano-biosensors for one-step multiplexed pathogen detection.

PubMed

Zuo, Peng; Li, XiuJun; Dominguez, Delfina C; Ye, Bang-Ce

2013-10-07

Infectious pathogens often cause serious public health concerns throughout the world. There is an increasing demand for simple, rapid and sensitive approaches for multiplexed pathogen detection. In this paper we have developed a polydimethylsiloxane (PDMS)/paper/glass hybrid microfluidic system integrated with aptamer-functionalized graphene oxide (GO) nano-biosensors for simple, one-step, multiplexed pathogen detection. The paper substrate used in this hybrid microfluidic system facilitated the integration of aptamer biosensors on the microfluidic biochip, and avoided complicated surface treatment and aptamer probe immobilization in a PDMS or glass-only microfluidic system. Lactobacillus acidophilus was used as a bacterium model to develop the microfluidic platform with a detection limit of 11.0 cfu mL(-1). We have also successfully extended this method to the simultaneous detection of two infectious pathogens - Staphylococcus aureus and Salmonella enterica. This method is simple and fast. The one-step 'turn on' pathogen assay in a ready-to-use microfluidic device only takes ~10 min to complete on the biochip. Furthermore, this microfluidic device has great potential in rapid detection of a wide variety of different other bacterial and viral pathogens.

A PDMS/paper/glass hybrid microfluidic biochip integrated with aptamer-functionalized graphene oxide nano-biosensors for one-step multiplexed pathogen detection

PubMed Central

Zuo, Peng; Dominguez, Delfina C.; Ye, Bang-Ce

2014-01-01

Infectious pathogens often cause serious public health concerns throughout the world. There is an increasing demand for simple, rapid and sensitive approaches for multiplexed pathogen detection. In this paper we have developed a polydimethylsiloxane (PDMS)/paper/glass hybrid microfluidic system integrated with aptamer-functionalized graphene oxide (GO) nano-biosensors for simple, one-step, multiplexed pathogen detection. The paper substrate used in this hybrid microfluidic system facilitated the integration of aptamer biosensors on the microfluidic biochip, and avoided complicated surface treatment and aptamer probe immobilization in a PDMS or glass-only microfluidic system. Lactobacillus acidophilus was used as a bacterium model to develop the microfluidic platform with a detection limit of 11.0 cfu mL−1. We have also successfully extended this method to the simultaneous detection of two infectious pathogens - Staphylococcus aureus and Salmonella enterica. This method is simple and fast. The one-step ‘turn on’ pathogen assay in a ready-to-use microfluidic device only takes ~10 min to complete on the biochip. Furthermore, this microfluidic device has great potential in rapid detection of a wide variety of different other bacterial and viral pathogens. PMID:23929394

Microfluidics and microbial engineering.

PubMed

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

2016-02-07

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

Geometric effects in microfluidics on heterogeneous cell stress using an Eulerian-Lagrangian approach.

PubMed

Warren, K M; Mpagazehe, J N; LeDuc, P R; Higgs, C F

2016-02-07

The response of individual cells at the micro-scale in cell mechanics is important in understanding how they are affected by changing environments. To control cell stresses, microfluidics can be implemented since there is tremendous control over the geometry of the devices. Designing microfluidic devices to induce and manipulate stress levels on biological cells can be aided by computational modeling approaches. Such approaches serve as an efficient precursor to fabricating various microfluidic geometries that induce predictable levels of stress on biological cells, based on their mechanical properties. Here, a three-dimensional, multiphase computational fluid dynamics (CFD) modeling approach was implemented for soft biological materials. The computational model incorporates the physics of the particle dynamics, fluid dynamics and solid mechanics, which allows us to study how stresses affect the cells. By using an Eulerian-Lagrangian approach to treat the fluid domain as a continuum in the microfluidics, we are conducting studies of the cells' movement and the stresses applied to the cell. As a result of our studies, we were able to determine that a channel with periodically alternating columns of obstacles was capable of stressing cells at the highest rate, and that microfluidic systems can be engineered to impose heterogenous cell stresses through geometric configuring. We found that when using controlled geometries of the microfluidics channels with staggered obstructions, we could increase the maximum cell stress by nearly 200 times over cells flowing through microfluidic channels with no obstructions. Incorporating computational modeling in the design of microfluidic configurations for controllable cell stressing could help in the design of microfludic devices for stressing cells such as cell homogenizers.

3D printed Lego®-like modular microfluidic devices based on capillary driving.

PubMed

Nie, Jing; Gao, Qing; Qiu, Jing-Jiang; Sun, Miao; Liu, An; Shao, Lei; Fu, Jian-Zhong; Zhao, Peng; He, Yong

2018-03-12

The field of how to rapidly assemble microfluidics with modular components continuously attracts researchers' attention, however, extra efforts must be devoted to solving the problems of leaking and aligning between individual modules. This paper presents a novel type of modular microfluidic device, driven by capillary force. There is no necessity for a strict seal or special alignment, and its open structures make it easy to integrate various stents and reactants. The key rationale for this method is to print different functional modules with a low-cost three-dimensional (3D) printer, then fill the channels with capillary materials and assemble them with plugs like Lego ® bricks. This rapidly reconstructed modular microfluidic device consists of a variety of common functional modules and other personalized modules, each module having a unified standard interface for easy assembly. As it can be printed by a desktop 3D printer, the manufacturing process is simple and efficient, with controllable regulation of the flow channel scale. Through diverse combinations of different modules, a variety of different functions can be achieved, without duplicating the manufacturing process. A single module can also be taken out for testing and analysis. What's more, combined with basic circuit components, it can serve as a low-cost Lego ® -like modular microfluidic circuits. As a proof of concept, the modular microfluidic device has been successfully demonstrated and used for stent degradation and cell cultures, revealing the potential use of this method in both chemical and biological research.

A Microfluidic Platform for High-Throughput Multiplexed Protein Quantitation

PubMed Central

Volpetti, Francesca; Garcia-Cordero, Jose; Maerkl, Sebastian J.

2015-01-01

We present a high-throughput microfluidic platform capable of quantitating up to 384 biomarkers in 4 distinct samples by immunoassay. The microfluidic device contains 384 unit cells, which can be individually programmed with pairs of capture and detection antibody. Samples are quantitated in each unit cell by four independent MITOMI detection areas, allowing four samples to be analyzed in parallel for a total of 1,536 assays per device. We show that the device can be pre-assembled and stored for weeks at elevated temperature and we performed proof-of-concept experiments simultaneously quantitating IL-6, IL-1β, TNF-α, PSA, and GFP. Finally, we show that the platform can be used to identify functional antibody combinations by screening 64 antibody combinations requiring up to 384 unique assays per device. PMID:25680117

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

PubMed

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

2016-07-26

One of the most popular methods to fabricate biomedical microfluidic devices is by using a soft-lithography technique. However, the fabrication of the moulds to produce microfluidic devices, such as SU-8 moulds, usually requires a cleanroom environment that can be quite costly. Therefore, many efforts have been made to develop low-cost alternatives for the fabrication of microstructures, avoiding the use of cleanroom facilities. Recently, low-cost techniques without cleanroom facilities that feature aspect ratios more than 20, for fabricating those SU-8 moulds have been gaining popularity among biomedical research community. In those techniques, Ultraviolet (UV) exposure equipment, commonly used in the Printed Circuit Board (PCB) industry, replaces the more expensive and less available Mask Aligner that has been used in the last 15 years for SU-8 patterning. Alternatively, non-lithographic low-cost techniques, due to their ability for large-scale production, have increased the interest of the industrial and research community to develop simple, rapid and low-cost microfluidic structures. These alternative techniques include Print and Peel methods (PAP), laserjet, solid ink, cutting plotters or micromilling, that use equipment available in almost all laboratories and offices. An example is the xurography technique that uses a cutting plotter machine and adhesive vinyl films to generate the master moulds to fabricate microfluidic channels. In this review, we present a selection of the most recent lithographic and non-lithographic low-cost techniques to fabricate microfluidic structures, focused on the features and limitations of each technique. Only microfabrication methods that do not require the use of cleanrooms are considered. Additionally, potential applications of these microfluidic devices in biomedical engineering are presented with some illustrative examples. Copyright © 2015 Elsevier Ltd. All rights reserved.

ElectroTaxis-on-a-Chip (ETC): an integrated quantitative high-throughput screening platform for electrical field-directed cell migration.

PubMed

Zhao, Siwei; Zhu, Kan; Zhang, Yan; Zhu, Zijie; Xu, Zhengping; Zhao, Min; Pan, Tingrui

2014-11-21

Both endogenous and externally applied electrical stimulation can affect a wide range of cellular functions, including growth, migration, differentiation and division. Among those effects, the electrical field (EF)-directed cell migration, also known as electrotaxis, has received broad attention because it holds great potential in facilitating clinical wound healing. Electrotaxis experiment is conventionally conducted in centimetre-sized flow chambers built in Petri dishes. Despite the recent efforts to adapt microfluidics for electrotaxis studies, the current electrotaxis experimental setup is still cumbersome due to the needs of an external power supply and EF controlling/monitoring systems. There is also a lack of parallel experimental systems for high-throughput electrotaxis studies. In this paper, we present a first independently operable microfluidic platform for high-throughput electrotaxis studies, integrating all functional components for cell migration under EF stimulation (except microscopy) on a compact footprint (the same as a credit card), referred to as ElectroTaxis-on-a-Chip (ETC). Inspired by the R-2R resistor ladder topology in digital signal processing, we develop a systematic approach to design an infinitely expandable microfluidic generator of EF gradients for high-throughput and quantitative studies of EF-directed cell migration. Furthermore, a vacuum-assisted assembly method is utilized to allow direct and reversible attachment of our device to existing cell culture media on biological surfaces, which separates the cell culture and device preparation/fabrication steps. We have demonstrated that our ETC platform is capable of screening human cornea epithelial cell migration under the stimulation of an EF gradient spanning over three orders of magnitude. The screening results lead to the identification of the EF-sensitive range of that cell type, which can provide valuable guidance to the clinical application of EF-facilitated wound healing.

Microfluidic devices with thick-film electrochemical detection

DOEpatents

Wang, Joseph; Tian, Baomin; Sahlin, Eskil

2005-04-12

An apparatus for conducting a microfluidic process and analysis, including at least one elongated microfluidic channel, fluidic transport means for transport of fluids through the microfluidic channel, and at least one thick-film electrode in fluidic connection with the outlet end of the microfluidic channel. The present invention includes an integrated on-chip combination reaction, separation and thick-film electrochemical detection microsystem, for use in detection of a wide range of analytes, and methods for the use thereof.

Label-free in-flow detection of single DNA molecules using glass nanopipettes.

PubMed

Gong, Xiuqing; Patil, Amol V; Ivanov, Aleksandar P; Kong, Qingyuan; Gibb, Thomas; Dogan, Fatma; deMello, Andrew J; Edel, Joshua B

2014-01-07

With the view of enhancing the functionality of label-free single molecule nanopore-based detection, we have designed and developed a highly robust, mechanically stable, integrated nanopipette-microfluidic device which combines the recognized advantages of microfluidic systems and the unique properties/advantages of nanopipettes. Unlike more typical planar solid-state nanopores, which have inherent geometrical constraints, nanopipettes can be easily positioned at any point within a microfluidic channel. This is highly advantageous, especially when taking into account fluid flow properties. We show that we are able to detect and discriminate between DNA molecules of varying lengths when motivated through a microfluidic channel, upon the application of appropriate voltage bias across the nanopipette. The effects of applied voltage and volumetric flow rates have been studied to ascertain translocation event frequency and capture rate. Additionally, by exploiting the advantages associated with microfluidic systems (such as flow control and concomitant control over analyte concentration/presence), we show that the technology offers a new opportunity for single molecule detection and recognition in microfluidic devices.

Microfluidic devices for cell cultivation and proliferation

PubMed Central

Tehranirokh, Masoomeh; Kouzani, Abbas Z.; Francis, Paul S.; Kanwar, Jagat R.

2013-01-01

Microfluidic technology provides precise, controlled-environment, cost-effective, compact, integrated, and high-throughput microsystems that are promising substitutes for conventional biological laboratory methods. In recent years, microfluidic cell culture devices have been used for applications such as tissue engineering, diagnostics, drug screening, immunology, cancer studies, stem cell proliferation and differentiation, and neurite guidance. Microfluidic technology allows dynamic cell culture in microperfusion systems to deliver continuous nutrient supplies for long term cell culture. It offers many opportunities to mimic the cell-cell and cell-extracellular matrix interactions of tissues by creating gradient concentrations of biochemical signals such as growth factors, chemokines, and hormones. Other applications of cell cultivation in microfluidic systems include high resolution cell patterning on a modified substrate with adhesive patterns and the reconstruction of complicated tissue architectures. In this review, recent advances in microfluidic platforms for cell culturing and proliferation, for both simple monolayer (2D) cell seeding processes and 3D configurations as accurate models of in vivo conditions, are examined. PMID:24273628

Optofluidics for handling and analysis of single living cells

NASA Astrophysics Data System (ADS)

Perozziello, Gerardo; Candeloro, Patrizio; Coluccio, Maria Laura; Di Fabrizio, Enzo

2017-11-01

Optofluidics is a field with important applications in areas such as biotechnology, chemical synthesis and analytical chemistry. Optofluidic devices combine optical elements into microfluidic devices in ways that increase portability and sensitivity of analysis for diagnostic or screening purposes .In fact in these devices fluids give fine adaptability, mobility and accessibility to nanoscale photonic devices which otherwise could not be realized using conventional devices. This review describes several cases inwhich optical or microfluidic approaches are used to trap single cells in proximity of integrated optical sensor for being analysed.

Detection of heavy metal by paper-based microfluidics.

PubMed

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

2016-09-15

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

High-speed droplet actuation on single-plate electrode arrays.

PubMed

Banerjee, Arghya Narayan; Qian, Shizhi; Joo, Sang Woo

2011-10-15

This paper reports a droplet-based microfluidic device composed of patterned co-planar electrodes in an all-in-a-single-plate arrangement and coated with dielectric layers for electrowetting-on-dielectric (EWOD) actuation of discrete droplets. The co-planar arrangement is preferred over conventional two-plate electrowetting devices because it provides simpler manufacturing process, reduced viscous drag, and easier liquid-handling procedures. These advantages lead to more versatile and efficient microfluidic devices capable of generating higher droplet speed and can incorporate various other droplet manipulation functions into the system for biological, sensing, and other microfluidic applications. We have designed, fabricated, and tested the devices using an insulating layer with materials having relatively high dielectric constant (SiO(2)) and compared the results with polymer coatings (Cytop) with low dielectric constant. Results show that the device with high dielectric layer generates more reproducible droplet transfer over a longer distance with a 25% reduction in the actuation voltage with respect to the polymer coatings, leading to more energy efficient microfluidic applications. We can generate droplet speeds as high as 26 cm/s using materials with high dielectric constant such as SiO(2). Copyright © 2011. Published by Elsevier Inc.

Wirelessly powered microfluidic dielectrophoresis devices using printable RF circuits.

PubMed

Qiao, Wen; Cho, Gyoujin; Lo, Yu-Hwa

2011-03-21

We report the first microfluidic device integrated with a printed RF circuit so the device can be wirelessly powered by a commercially available RFID reader. For conventional dielectrophoresis devices, electrical wires are needed to connect the electric components on the microchip to external equipment such as power supplies, amplifiers, function generators, etc. Such a procedure is unfamiliar to most clinicians and pathologists who are used to working with a microscope for examination of samples on microscope slides. The wirelessly powered device reported here eliminates the entire need for wire attachments and external instruments so the operators can use the device in essentially the same manner as they do with microscope slides. The integrated circuit can be fabricated on a flexible plastic substrate at very low cost using a roll-to-roll printing method. Electrical power at 13.56 MHz transmitted by a radio-frequency identification (RFID) reader is inductively coupled to the printed RFIC and converted into 10 V DC (direct current) output, which provides sufficient power to drive a microfluidic device to manipulate biological particles such as beads and proteins via the DC dielectrophoresis (DC-DEP) effect. To our best knowledge, this is the first wirelessly powered microfluidic dielectrophoresis device. Although the work is preliminary, the device concept, the architecture, and the core technology are expected to stimulate many efforts in the future and transform the technology to a wide range of clinical and point-of-care applications. This journal is © The Royal Society of Chemistry 2011

Centrifugal sedimentation for selectively packing channels with silica microbeads in three-dimensional micro/nanofluidic devices.

PubMed

Gong, Maojun; Bohn, Paul W; Sweedler, Jonathan V

2009-03-01

Incorporation of nanofluidic elements into microfluidic channels is one approach for adding filtration and partition functionality to planar microfluidic devices, as well as providing enhanced biomolecular separations. Here we introduce a strategy to pack microfluidic channels with silica nanoparticles and microbeads, thereby indirectly producing functional nanostructures; the method allows selected channels to be packed, here demonstrated so that a separation channel is packed while keeping an injection channel unpacked. A nanocapillary array membrane is integrated between two patterned microfluidic channels that cross each other in vertically separated layers. The membrane serves both as a frit for bead packing and as a fluid communication conduit between microfluidic channels. Centrifugal force-assisted sedimentation is then used to selectively pack the microfluidic channels using an aqueous silica bead suspension loaded into the appropriate inlet reservoirs. This packing approach may be used to simultaneously pack multiple channels with silica microbeads having different sizes and surface properties. The chip design and packing method introduced here are suitable for packing silica particles in sizes ranging from nanometers to micrometers and allow rapid (approximately 10 min) packing with high quality. The liquid/analyte transport characteristics of these packed micro/nanofluidic devices have potential utility in a wide range of applications, including electroosmotic pumping, liquid chromatographic separations, and electrochromatography.

A programmable microfluidic static droplet array for droplet generation, transportation, fusion, storage, and retrieval.

PubMed

Jin, Si Hyung; Jeong, Heon-Ho; Lee, Byungjin; Lee, Sung Sik; Lee, Chang-Soo

2015-01-01

We present a programmable microfluidic static droplet array (SDA) device that can perform user-defined multistep combinatorial protocols. It combines the passive storage of aqueous droplets without any external control with integrated microvalves for discrete sample dispensing and dispersion-free unit operation. The addressable picoliter-volume reaction is systematically achieved by consecutively merging programmable sequences of reagent droplets. The SDA device is remarkably reusable and able to perform identical enzyme kinetic experiments at least 30 times via automated cross-contamination-free removal of droplets from individual hydrodynamic traps. Taking all these features together, this programmable and reusable universal SDA device will be a general microfluidic platform that can be reprogrammed for multiple applications.

Optimization of monolithic columns for microfluidic devices

NASA Astrophysics Data System (ADS)

Pagaduan, Jayson V.; Yang, Weichun; Woolley, Adam T.

2011-06-01

Monolithic columns offer advantages as solid-phase extractors because they offer high surface area that can be tailored to a specific function, fast mass transport, and ease of fabrication. Porous glycidyl methacrylate-ethylene glycol dimethacrylate monoliths were polymerized in-situ in microfluidic devices, without pre-treatment of the poly(methyl methacrylate) channel surface. Cyclohexanol, 1-dodecanol and Tween 20 were used to control the pore size of the monoliths. The epoxy groups on the monolith surface can be utilized to immobilize target-specific probes such as antibodies, aptamers, or DNA for biomarker detection. Microfluidic devices integrated with solid-phase extractors should be useful for point-of-care diagnostics in detecting specific biomarkers from complex biological fluids.

A Fast Microfluidic Temperature Control Device for Studying Microtubule Dynamics in Fission Yeast

PubMed Central

Velve-Casquillas, Guilhem; Costa, Judite; Carlier-Grynkorn, Frédérique; Mayeux, Adeline; Tran, Phong T.

2010-01-01

Recent development in soft lithography and microfluidics enables biologists to create tools to control the cellular microenvironment. One such control is the ability to quickly change the temperature of the cells. Genetic model organism such as fission yeast has been useful for studies of the cell cytoskeleton. In particular, the dynamic microtubule cytoskeleton responds to changes in temperature. In addition, there are temperature-sensitive mutations of cytoskeletal proteins. We describe here the fabrication and use of a microfluidic device to quickly and reversibly change cellular temperature between 2°C and 50°C. We demonstrate the use of this device while imaging at high-resolution microtubule dynamics in fission yeast. PMID:20719272

Microfluidic device for the assembly and transport of microparticles

DOEpatents

James, Conrad D [Albuquerque, NM; Kumar, Anil [Framingham, MA; Khusid, Boris [New Providence, NJ; Acrivos, Andreas [Stanford, CA

2010-06-29

A microfluidic device comprising independently addressable arrays of interdigitated electrodes can be used to assembly and transport large-scale microparticle structures. The device and method uses collective phenomena in a negatively polarized suspension exposed to a high-gradient strong ac electric field to assemble the particles into predetermined locations and then transport them collectively to a work area for final assembly by sequentially energizing the electrode arrays.

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

DOEpatents

Frechet, Jean M. J. [Oakland, CA; Svec, Frantisek [Alameda, CA; Rohr, Thomas [Leiden, NL

2008-10-07

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

Microfluidic electrochemical device and process for chemical imaging and electrochemical analysis at the electrode-liquid interface in-situ

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yu, Xiao-Ying; Liu, Bingwen; Yang, Li

2016-03-01

A microfluidic electrochemical device and process are detailed that provide chemical imaging and electrochemical analysis under vacuum at the surface of the electrode-sample or electrode-liquid interface in-situ. The electrochemical device allows investigation of various surface layers including diffuse layers at selected depths populated with, e.g., adsorbed molecules in which chemical transformation in electrolyte solutions occurs.

Fabrication of zein nanostructure

NASA Astrophysics Data System (ADS)

Luecha, Jarupat

The concerns on the increase of polluting plastic wastes as well as the U.S. dependence on imported petrochemical products have driven an attention towards alternative biodegradable polymers from renewable resources. Zein protein, a co-product from ethanol production from corn, is a good candidate. This research project aims to increase zein value by adopting nanotechnology for fabricating advanced zein packaging films and zein microfluidic devices. Two nanotechnology approaches were focused: the polymer nanoclay nanocomposite technique where the nanocomposite structures were created in the zein matrix, and the soft lithography and the microfluidic devices where the micro and nanopatterns were created on the zein film surfaces. The polymer nanoclay nanocomposite technique was adopted in the commonly used zein film fabrication processes which were solvent casting and extrusion blowing methods. The two methods resulted in partially exfoliated nanocomposite structures. The impact of nanoclays on the physical properties of zein films strongly depended on the film preparation techniques. The impact of nanoclay concentration was more pronounced in the films made by extrusion blowing technique than by the solvent casting technique. As the processability limitation for the extrusion blowing technique of the zein sample containing hight nanoclay content, the effect of the nanoclay content on the rheological properties of zein hybrid resins at linear and nonlinear viscoelastic regions were further investigated. A pristine zein resin exhibited soft solid like behavior. On the other hand, the zein hybrid with nanoclay content greater than 5 wt.% showed more liquid like behavior, suggesting that the nanoclays interrupted the entangled zein network. There was good correspondence between the experimental data and the predictions of the Wagner model for the pristine zein resins. However, the model failed to predict the steady shear properties of the zein nanoclay nanocomposite resins. The soft lithography technique was mainly used to fabricate micro and nanostructures on zein films. Zein material well-replicated small structures with the smallest size at sub micrometer scale that resulted in interesting photonic properties. The bonding method was also developed for assembling portable zein microfluidic devices with small shape distortion. Zein-zein and zein-glass microfluidic devices demonstrated sufficient strength to facilitate fluid flow in a complex microfluidic design with no leakage. Aside from the fabrication technique development, several potential applications of this environmentally friendly microfluidic device were investigated. The concentration gradient manipulation of Rhodamine B solution in zein-glass microfluidic devices was demonstrated. The diffusion of small molecules such as fluorescent dye into the wall of the zein microfluidic channels was observed. However, with this formulation, zein microfluidic devices were not suitable for cell culture applications. This pioneer study covered a wide spectrum of the implementation of the two nanotechnology approaches to advance zein biomaterial which provided proof of fundamental concepts as well as presenting some limitations. The findings in this study can lead to several innovative research opportunities of advanced zein biomaterials with broad applications. The information from the study of zein nanocomposite structure allows the packaging industry to develop the low cost biodegradable materials with physical property improvement. The information from the study of the zein microfluidic devices allows agro-industry to develop the nanotechnology-enabled microfluidic sensors fabricated entirely from biodegradable polymer for on-site disease or contaminant detection in the fields of food and agriculture.

Spintronic microfluidic platform for biomedical and environmental applications

NASA Astrophysics Data System (ADS)

Cardoso, F. A.; Martins, V. C.; Fonseca, L. P.; Germano, J.; Sousa, L. A.; Piedade, M. S.; Freitas, P. P.

2010-09-01

Faster, more sensitive and easy to operate biosensing devices still are a need at important areas such as biomedical diagnostics, food control and environmental monitoring. Recently, spintronic-devices have emerged as a promising alternative to the existent technologies [1-3]. A number of advantages, namely high sensitivity, easy integration, miniaturization, scalability, robustness and low cost make these devices potentially capable of responding to the existent technological need. In parallel, the field of microfluidics has shown great advances [4]. Microfluidic systems allow the analysis of small sample volumes (from micro- down to pico-liters), often by automate sample processing with the ability to integrate several steps into a single device (analyte amplification, concentration, separation and/or labeling), all in a reduced assay time (minutes to hours) and affordable cost. The merging of these two technologies, magnetoresistive biochips and microfluidics, will enable the development of highly competitive devices. This work reports the integration of a magnetoresistive biochip with a microfluidic system inside a portable and autonomous electronic platform aiming for a fully integrated device. A microfluidic structure fabricated in polydimethylsiloxane with dimensions of W: 0.5mm, H: 0.1mm, L: 10mm, associated to a mechanical system to align and seal the channel by pressure is presented (Fig. 1) [5]. The goal is to perform sample loading and transportation over the chip and simultaneously control the stringency and uniformity of the wash-out process. The biochip output is acquired by an electronic microsystem incorporating the circuitry to control, address and read-out the 30 spin-valve sensors sequentially (Fig. 1) [2]. This platform is being applied to the detection of water-borne microbial pathogens (e.g. Salmonella and Escherichia coli) and genetic diseases diagnosis (e.g. cystic fibrosis) through DNA hybridization assays. Open chamber measurements were performed as described elsewhere [2]. Briefly, a 20 μl sample droplet is manually dispensed over the chip, limited by a polymeric frame. When using the microfluidic system for sample loading, a known volume of sample is introduced into the fluidic system through the help of a syringe pump at a controlled velocity.

A microfluidic platform for chemical stimulation and real time analysis of catecholamine secretion from neuroendocrine cells

PubMed Central

Ges, Igor A.; Brindley, Rebecca L.; Currie, Kevin P.M.; Baudenbacher, Franz J.

2013-01-01

Release of neurotransmitters and hormones by calcium-regulated exocytosis is a fundamental cellular process that is disrupted in a variety of psychiatric, neurological, and endocrine disorders. As such, there is significant interest in targeting neurosecretion for drug and therapeutic development, efforts that will be aided by novel analytical tools and devices that provide mechanistic insight coupled with increased experimental throughput. Here, we report a simple, inexpensive, reusable, microfluidic device designed to analyze catecholamine secretion from small populations of adrenal chromaffin cells in real time, an important neuroendocrine component of the sympathetic nervous system and versatile neurosecretory model. The device is fabricated by replica molding of polydimethylsiloxane (PDMS) using patterned photoresist on silicon wafer as the master. Microfluidic inlet channels lead to an array of U-shaped “cell traps”, each capable of immobilizing single or small groups of chromaffin cells. The bottom of the device is a glass slide with patterned thin film platinum electrodes used for electrochemical detection of catecholamines in real time. We demonstrate reliable loading of the device with small populations of chromaffin cells, and perfusion / repetitive stimulation with physiologically relevant secretagogues (carbachol, PACAP, KCl) using the microfluidic network. Evoked catecholamine secretion was reproducible over multiple rounds of stimulation, and graded as expected to different concentrations of secretagogue or removal of extracellular calcium. Overall, we show this microfluidic device can be used to implement complex stimulation paradigms and analyze the amount and kinetics of catecholamine secretion from small populations of neuroendocrine cells in real time. PMID:24126415

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

ERIC Educational Resources Information Center

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

2015-01-01

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

Novel concept of washing for microfluidic paper-based analytical devices based on capillary force of paper substrates.

PubMed

Mohammadi, Saeed; Busa, Lori Shayne Alamo; Maeki, Masatoshi; Mohamadi, Reza M; Ishida, Akihiko; Tani, Hirofumi; Tokeshi, Manabu

2016-11-01

A novel washing technique for microfluidic paper-based analytical devices (μPADs) that is based on the spontaneous capillary action of paper and eliminates unbound antigen and antibody in a sandwich immunoassay is reported. Liquids can flow through a porous medium (such as paper) in the absence of external pressure as a result of capillary action. Uniform results were achieved when washing a paper substrate in a PDMS holder which was integrated with a cartridge absorber acting as a porous medium. Our study demonstrated that applying this washing technique would allow μPADs to become the least expensive microfluidic device platform with high reproducibility and sensitivity. In a model μPAD assay that utilized this novel washing technique, C-reactive protein (CRP) was detected with a limit of detection (LOD) of 5 μg mL -1 . Graphical Abstract A novel washing technique for microfluidic paper-based analytical devices (μPADs) that is based on the spontaneous capillary action of paper and eliminates unbound antigen and antibody in a sandwich immunoassay is reported.

Bead mediated separation of microparticles in droplets.

PubMed

Wang, Sida; Sung, Ki-Joo; Lin, Xiaoxia Nina; Burns, Mark A

2017-01-01

Exchange of components such as particles and cells in droplets is important and highly desired in droplet microfluidic assays, and many current technologies use electrical or magnetic fields to accomplish this process. Bead-based microfluidic techniques offer an alternative approach that uses the bead's solid surface to immobilize targets like particles or biological material. In this paper, we demonstrate a bead-based technique for exchanging droplet content by separating fluorescent microparticles in a microfluidic device. The device uses posts to filter surface-functionalized beads from a droplet and re-capture the filtered beads in a new droplet. With post spacing of 7 μm, beads above 10 μm had 100% capture efficiency. We demonstrate the efficacy of this system using targeted particles that bind onto the functionalized beads and are, therefore, transferred from one solution to another in the device. Binding capacity tests performed in the bulk phase showed an average binding capacity of 5 particles to each bead. The microfluidic device successfully separated the targeted particles from the non-targeted particles with up to 98% purity and 100% yield.

Bead mediated separation of microparticles in droplets

PubMed Central

Sung, Ki-Joo; Lin, Xiaoxia Nina; Burns, Mark A.

2017-01-01

Exchange of components such as particles and cells in droplets is important and highly desired in droplet microfluidic assays, and many current technologies use electrical or magnetic fields to accomplish this process. Bead-based microfluidic techniques offer an alternative approach that uses the bead’s solid surface to immobilize targets like particles or biological material. In this paper, we demonstrate a bead-based technique for exchanging droplet content by separating fluorescent microparticles in a microfluidic device. The device uses posts to filter surface-functionalized beads from a droplet and re-capture the filtered beads in a new droplet. With post spacing of 7 μm, beads above 10 μm had 100% capture efficiency. We demonstrate the efficacy of this system using targeted particles that bind onto the functionalized beads and are, therefore, transferred from one solution to another in the device. Binding capacity tests performed in the bulk phase showed an average binding capacity of 5 particles to each bead. The microfluidic device successfully separated the targeted particles from the non-targeted particles with up to 98% purity and 100% yield. PMID:28282412

A Novel Microfluidic Device for Isolation of Circulating Tumor Cells from Pancreatic Cancer Blood Samples.

PubMed

Varillas, Jose I; Chen, Kangfu; Zhang, Jinling; George, Thomas J; Hugh Fan, Z

2017-01-01

Enumeration of circulating tumor cells (CTCs) can provide valuable prognostic information to guide cancer treatment as well as help monitor disease progression. Analysis of these rare malignant cells has the potential to further our understanding of cancer metastasis by gaining insights into CTC characteristics and properties. Microfluidics presents a unique platform to isolate and study CTCs. In this chapter, we describe the detailed procedures for the fabrication and use of a microfluidic device to detect CTCs from the blood of pancreatic cancer patients.

Resolution improvement of 3D stereo-lithography through the direct laser trajectory programming: Application to microfluidic deterministic lateral displacement device.

PubMed

Juskova, Petra; Ollitrault, Alexis; Serra, Marco; Viovy, Jean-Louis; Malaquin, Laurent

2018-02-13

The vast majority of current microfluidic devices are produced using soft lithography, a technique with strong limitations regarding the fabrication of three-dimensional architectures. Additive manufacturing holds great promises to overcome these limitations, but conventional machines still lack the resolution required by most microfluidic applications. 3D printing machines based on two-photon lasers, in contrast, have the needed resolution but are too limited in speed and size of the global device. Here we demonstrate how the resolution of conventional stereolithographic machines can be improved by a direct programming of the laser path and can contribute to bridge the gap between the two above technologies, allowing the direct printing of features between 10 and 100 μm, corresponding to a large fraction of microfluidic applications. This strategy allows to achieve resolutions limited only by the physical size of the laser beam, decreasing by a factor at least 2× the size of the smallest features printable, and increasing their reproducibility by a factor 5. The approach was applied to produce an open microfluidic device with the reversible seal, integrating periodical patterns using the simple motifs, and validated by the fabrication of a deterministic lateral displacement particles sorting device. The sorting of polystyrene beads (diameter: 20 μm and 45 μm) was achieved with a specificity >95%, comparable with that achieved with arrays prepared by microlithography. Copyright © 2017 Elsevier B.V. All rights reserved.

Visual Estimation of Bacterial Growth Level in Microfluidic Culture Systems.

PubMed

Kim, Kyukwang; Kim, Seunggyu; Jeon, Jessie S

2018-02-03

Microfluidic devices are an emerging platform for a variety of experiments involving bacterial cell culture, and has advantages including cost and convenience. One inevitable step during bacterial cell culture is the measurement of cell concentration in the channel. The optical density measurement technique is generally used for bacterial growth estimation, but it is not applicable to microfluidic devices due to the small sample volumes in microfluidics. Alternately, cell counting or colony-forming unit methods may be applied, but these do not work in situ; nor do these methods show measurement results immediately. To this end, we present a new vision-based method to estimate the growth level of the bacteria in microfluidic channels. We use Fast Fourier transform (FFT) to detect the frequency level change of the microscopic image, focusing on the fact that the microscopic image becomes rough as the number of cells in the field of view increases, adding high frequencies to the spectrum of the image. Two types of microfluidic devices are used to culture bacteria in liquid and agar gel medium, and time-lapsed images are captured. The images obtained are analyzed using FFT, resulting in an increase in high-frequency noise proportional to the time passed. Furthermore, we apply the developed method in the microfluidic antibiotics susceptibility test by recognizing the regional concentration change of the bacteria that are cultured in the antibiotics gradient. Finally, a deep learning-based data regression is performed on the data obtained by the proposed vision-based method for robust reporting of data.

The Deformation of Polydimethylsiloxane (PDMS) Microfluidic Channels Filled with Embedded Circular Obstacles under Certain Circumstances.

PubMed

Roh, Changhyun; Lee, Jaewoong; Kang, Chankyu

2016-06-18

Experimental investigations were conducted to determine the influence of polydimethylsiloxane (PDMS) microfluidic channels containing aligned circular obstacles (with diameters of 172 µm and 132 µm) on the flow velocity and pressure drop under steady-state flow conditions. A significant PDMS bulging was observed when the fluid flow initially contacted the obstacles, but this phenomenon decreased in the 1 mm length of the microfluidic channels when the flow reached a steady-state. This implies that a microfluidic device operating with steady-state flows does not provide fully reliable information, even though less PDMS bulging is observed compared to quasi steady-state flow. Numerical analysis of PDMS bulging using ANSYS Workbench showed a relatively good agreement with the measured data. To verify the influence of PDMS bulging on the pressure drop and flow velocity, theoretical analyses were performed and the results were compared with the experimental results. The measured flow velocity and pressure drop data relatively matched well with the classical prediction under certain circumstances. However, discrepancies were generated and became worse as the microfluidic devices were operated under the following conditions: (1) restricted geometry of the microfluidic channels (i.e., shallow channel height, large diameter of obstacles and a short microchannel length); (2) operation in quasi-steady state flow; (3) increasing flow rates; and (4) decreasing amount of curing agent in the PDMS mixture. Therefore, in order to obtain reliable data a microfluidic device must be operated under appropriate conditions.

A Microfluidic Approach for Studying Piezo Channels.

PubMed

Maneshi, M M; Gottlieb, P A; Hua, S Z

2017-01-01

Microfluidics is an interdisciplinary field intersecting many areas in engineering. Utilizing a combination of physics, chemistry, biology, and biotechnology, along with practical applications for designing devices that use low volumes of fluids to achieve high-throughput screening, is a major goal in microfluidics. Microfluidic approaches allow the study of cells growth and differentiation using a variety of conditions including control of fluid flow that generates shear stress. Recently, Piezo1 channels were shown to respond to fluid shear stress and are crucial for vascular development. This channel is ideal for studying fluid shear stress applied to cells using microfluidic devices. We have developed an approach that allows us to analyze the role of Piezo channels on any given cell and serves as a high-throughput screen for drug discovery. We show that this approach can provide detailed information about the inhibitors of Piezo channels. Copyright © 2017 Elsevier Inc. All rights reserved.

Compact and controlled microfluidic mixing and biological particle capture

NASA Astrophysics Data System (ADS)

Ballard, Matthew; Owen, Drew; Mills, Zachary Grant; Hesketh, Peter J.; Alexeev, Alexander

2016-11-01

We use three-dimensional simulations and experiments to develop a multifunctional microfluidic device that performs rapid and controllable microfluidic mixing and specific particle capture. Our device uses a compact microfluidic channel decorated with magnetic features. A rotating magnetic field precisely controls individual magnetic microbeads orbiting around the features, enabling effective continuous-flow mixing of fluid streams over a compact mixing region. We use computer simulations to elucidate the underlying physical mechanisms that lead to effective mixing and compare them with experimental mixing results. We study the effect of various system parameters on microfluidic mixing to design an efficient micromixer. We also experimentally and numerically demonstrate that orbiting microbeads can effectively capture particles transported by the fluid, which has major implications in pre-concentration and detection of biological particles including various cells and bacteria, with applications in areas such as point-of-care diagnostics, biohazard detection, and food safety. Support from NSF and USDA is gratefully acknowledged.

Security Assessment of Cyberphysical Digital Microfluidic Biochips.

PubMed

Ali, Sk Subidh; Ibrahim, Mohamed; Sinanoglu, Ozgur; Chakrabarty, Krishnendu; Karri, Ramesh

2016-01-01

A digital microfluidic biochip (DMFB) is an emerging technology that enables miniaturized analysis systems for point-of-care clinical diagnostics, DNA sequencing, and environmental monitoring. A DMFB reduces the rate of sample and reagent consumption, and automates the analysis of assays. In this paper, we provide the first assessment of the security vulnerabilities of DMFBs. We identify result-manipulation attacks on a DMFB that maliciously alter the assay outcomes. Two practical result-manipulation attacks are shown on a DMFB platform performing enzymatic glucose assay on serum. In the first attack, the attacker adjusts the concentration of the glucose sample and thereby modifies the final result. In the second attack, the attacker tampers with the calibration curve of the assay operation. We then identify denial-of-service attacks, where the attacker can disrupt the assay operation by tampering either with the droplet-routing algorithm or with the actuation sequence. We demonstrate these attacks using a digital microfluidic synthesis simulator. The results show that the attacks are easy to implement and hard to detect. Therefore, this work highlights the need for effective protections against malicious modifications in DMFBs.

Fabrication of a microfluidic chip by UV bonding at room temperature for integration of temperature-sensitive layers

NASA Astrophysics Data System (ADS)

Schlautmann, S.; Besselink, G. A. J.; Radhakrishna Prabhu, G.; Schasfoort, R. B. M.

2003-07-01

A method for the bonding of a microfluidic device at room temperature is presented. The wafer with the fluidic structures was bonded to a sensor wafer with gold pads by means of adhesive bonding, utilizing an UV-curable glue layer. To avoid filling the fluidic channels with the glue, a stamping process was developed which allows the selective application of a thin glue layer. In this way a microfluidic glass chip was fabricated that could be used for performing surface plasmon resonance measurements without signs of leakage. The advantage of this method is the possibility of integration of organic layers as well as other temperature-sensitive layers into a microfluidic glass device.

Characterization of light-controlled Volvox as movable microvalve element assembled in multilayer microfluidic device

NASA Astrophysics Data System (ADS)

Nagai, Moeto; Oguri, Michihito; Shibata, Takayuki

2015-06-01

We report a model of a light-controlled microvalve driven by Volvox and characterization of Volvox as a movable microvalve element in a multilayer microfluidic device for development of the valve. First, a three-layer microfluidic device having a single through-hole was fabricated by a replica molding process. The fabricated devices met the requirements for experiments using Volvox. Second, we used the phototactic behavior of V. carteri and controlled its motions in a microchannel by illuminating light. V. carteri migrated to the light source in the channel. Third, a colony of V. carteri was placed on a microhole, and the colony was found to stop the flow compared to the flow without Volvox on the hole. The integration of all of the obtained findings is expected to lead to the fabrication of the proposed microvalve.

Formation of interconnections to microfluidic devices

DOEpatents

Matzke, Carolyn M [Los Lunas, NM; Ashby, Carol I. H. [Edgewood, NM; Griego, Leonardo [Tijeras, NM

2003-07-29

A method is disclosed to form external interconnections to a microfluidic device for coupling of a fluid or light or both into a microchannel of the device. This method can be used to form optical or fluidic interconnections to microchannels previously formed on a substrate, or to form both the interconnections and microchannels during the same process steps. The optical and fluidic interconnections are formed parallel to the plane of the substrate, and are fluid tight.

Quantitative Analysis of Cancer Cell Migration in Gradients Of EGF, HGF, and SDF-alpha Using a Microfluidic Chemotaxis Device

DTIC Science & Technology

2005-01-01

Quantitative Analysis of Cancer Cell Migration in Gradients of EGF, HGF, and SDF-alpha Using a Microfluidic Chemotaxis Device The University of California...allowing for parallel analysis . Additionally, simple methods of localizing gels into microdevices are demonstrated. The device was characterized by...To overcome some of these drawbacks, several approaches have utilized free diffusion to produce gradients in static environ - ments.5-9 However

Microfluidic evaporator for on-chip sample concentration.

PubMed

Casadevall i Solvas, Xavier; Turek, Vladimir; Prodromakis, Themistoklis; Edel, Joshua B

2012-10-21

We present a simple technique for the concentration of liquid samples in microfluidic devices applicable for single or multiple-phase configurations. The strategy consists of capturing the sample of interest within microfluidic traps and breaking its continuity by the introduction of a gas phase, which is also used to evaporate it.

Controlling the trajectories of bubble trains at a microfluidic junction

NASA Astrophysics Data System (ADS)

Parthiban, Pravien; Khan, Saif

2011-11-01

The increasing number of applications facilitated by digital microfluidic flows has resulted in a sustained interest in not only understanding the diverse, interesting and often complex dynamics associated with such flows in microchannel networks but also in developing facile strategies to control them. We find that there are readily accessible flow speeds wherein resistance to flow in microchannels decreases with an increase in the number of confined bubbles present, and exploit this intriguing phenomenon to sort all bubble of a train exclusively into one of the arms of a nominally symmetric microfluidic loop. We also demonstrate how the arm into which the train filters into can be chosen by applying a temporary external stimulus by means of an additional flow of the continuous liquid into one the arms of the loop. Furthermore, we show how by tuning the magnitude and period of this temporary stimulus we can switch controllably, the traffic of bubbles between both arms of the loop even when the loop is asymmetric. The results of this work should aid in developing viable methods to regulate traffic of digital flows in microfluidic networks.

Microfluidic perfusion culture.

PubMed

Hattori, Koji; Sugiura, Shinji; Kanamori, Toshiyuki

2014-01-01

Microfluidic perfusion culture is a novel technique to culture animal cells in a small-scale microchamber with medium perfusion. Polydimethylsiloxane (PDMS) is the most popular material to fabricate a microfluidic perfusion culture chip. Photolithography and replica molding techniques are generally used for fabrication of a microfluidic perfusion culture chip. Pressure-driven perfusion culture system is convenient technique to carry out the perfusion culture of animal cells in a microfluidic device. Here, we describe a general theory on microfluid network design, microfabrication technique, and experimental technique for pressure-driven perfusion culture in an 8 × 8 microchamber array on a glass slide-sized microchip made out of PDMS.

Characterization of three-dimensional cancer cell migration in mixed collagen-Matrigel scaffolds using microfluidics and image analysis.

PubMed

Anguiano, María; Castilla, Carlos; Maška, Martin; Ederra, Cristina; Peláez, Rafael; Morales, Xabier; Muñoz-Arrieta, Gorka; Mujika, Maite; Kozubek, Michal; Muñoz-Barrutia, Arrate; Rouzaut, Ana; Arana, Sergio; Garcia-Aznar, José Manuel; Ortiz-de-Solorzano, Carlos

2017-01-01

Microfluidic devices are becoming mainstream tools to recapitulate in vitro the behavior of cells and tissues. In this study, we use microfluidic devices filled with hydrogels of mixed collagen-Matrigel composition to study the migration of lung cancer cells under different cancer invasion microenvironments. We present the design of the microfluidic device, characterize the hydrogels morphologically and mechanically and use quantitative image analysis to measure the migration of H1299 lung adenocarcinoma cancer cells in different experimental conditions. Our results show the plasticity of lung cancer cell migration, which turns from mesenchymal in collagen only matrices, to lobopodial in collagen-Matrigel matrices that approximate the interface between a disrupted basement membrane and the underlying connective tissue. Our quantification of migration speed confirms a biphasic role of Matrigel. At low concentration, Matrigel facilitates migration, most probably by providing a supportive and growth factor retaining environment. At high concentration, Matrigel slows down migration, possibly due excessive attachment. Finally, we show that antibody-based integrin blockade promotes a change in migration phenotype from mesenchymal or lobopodial to amoeboid and analyze the effect of this change in migration dynamics, in regards to the structure of the matrix. In summary, we describe and characterize a robust microfluidic platform and a set of software tools that can be used to study lung cancer cell migration under different microenvironments and experimental conditions. This platform could be used in future studies, thus benefitting from the advantages introduced by microfluidic devices: precise control of the environment, excellent optical properties, parallelization for high throughput studies and efficient use of therapeutic drugs.

Enhancing depth of focus in tilted microfluidics channels by digital holography.

PubMed

Matrecano, Marcella; Paturzo, Melania; Finizio, Andrea; Ferraro, Pietro

2013-03-15

In this Letter we propose a method to enhance the limited depth of field (DOF) in optical imaging systems, through digital holography. The proposed approach is based on the introduction of a cubic phase plate into the diffraction integral, analogous to what occurs in white-light imaging systems. By this approach we show that it is possible to improve the DOF and to recover the extended focus image of a tilted object in a single reconstruction step. Moreover, we demonstrate the possibility of obtaining well-focused biological cells flowing into a tilted microfluidic channel.

Fundamentals of microfluidic cell culture in controlled microenvironments†

PubMed Central

Young, Edmond W. K.; Beebe, David J.

2010-01-01

Microfluidics has the potential to revolutionize the way we approach cell biology research. The dimensions of microfluidic channels are well suited to the physical scale of biological cells, and the many advantages of microfluidics make it an attractive platform for new techniques in biology. One of the key benefits of microfluidics for basic biology is the ability to control parameters of the cell microenvironment at relevant length and time scales. Considerable progress has been made in the design and use of novel microfluidic devices for culturing cells and for subsequent treatment and analysis. With the recent pace of scientific discovery, it is becoming increasingly important to evaluate existing tools and techniques, and to synthesize fundamental concepts that would further improve the efficiency of biological research at the microscale. This tutorial review integrates fundamental principles from cell biology and local microenvironments with cell culture techniques and concepts in microfluidics. Culturing cells in microscale environments requires knowledge of multiple disciplines including physics, biochemistry, and engineering. We discuss basic concepts related to the physical and biochemical microenvironments of the cell, physicochemical properties of that microenvironment, cell culture techniques, and practical knowledge of microfluidic device design and operation. We also discuss the most recent advances in microfluidic cell culture and their implications on the future of the field. The goal is to guide new and interested researchers to the important areas and challenges facing the scientific community as we strive toward full integration of microfluidics with biology. PMID:20179823

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

ERIC Educational Resources Information Center

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

2010-01-01

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

Fabrication of microfluidic devices in silica glass by water-assisted ablation with femtosecond laser pulses

NASA Astrophysics Data System (ADS)

Li, Yan; Qu, Shiliang; Guo, Zhongyi

2011-07-01

We have fabricated a microdiverter with a protrusion and a complicated micromixer with grid-like structures in silica glass by using water-assisted femtosecond laser ablation. When distilled water is introduced into the fabricated microchannel, the blocking and redepositing effects of ablated debris can be reduced greatly. The total length of the fabricated microfluidic devices is 6 mm without any deformation. The diameters of the fabricated microchannels can be controlled by changing the used pulse energies and the width of the laser-scanning region inside the sample. The experimental results show that it is possible to fabricate high-quality and high-aspect-ratio complicated microfluidic devices in single step without the need of using photosensitive glass or post-processing.

Integrated microelectrode array and microfluidics for temperature clamp of sensory neurons in culture.

PubMed

Pearce, Thomas M; Wilson, J Adam; Oakes, S George; Chiu, Shing-Yan; Williams, Justin C

2005-01-01

A device for cell culture is presented that combines MEMS technology and liquid-phase photolithography to create a microfluidic chip that influences and records electrical cellular activity. A photopolymer channel network is formed on top of a multichannel microelectrode array. Preliminary results indicated successful local thermal control within microfluidic channels and control of lamina position over the electrode array. To demonstrate the biological application of such a device, adult dissociated dorsal root ganglion neurons with a subpopulation of thermally-sensitive cells are attached onto the electrode array. Using laminar flow, dynamic control of local temperature of the neural cells was achieved while maintaining a constant chemical culture medium. Recording the expected altered cellular activity confirms the success of the integrated device.

Mass and Momentum Transport in Microcavities for Diffusion-Dominant Cell Culture Applications

NASA Technical Reports Server (NTRS)

Yew, Alvin G.; Pinero, Daniel; Hsieh, Adam H.; Atencia, Javier

2012-01-01

For the informed design of microfluidic devices, it is important to understand transport phenomena at the microscale. This letter outlines an analytically-driven approach to the design of rectangular microcavities extending perpendicular to a perfusion microchannel for microfluidic cell culture devices. We present equations to estimate the spatial transition from advection- to diffusion-dominant transport inside cavities as a function of the geometry and flow conditions. We also estimate the time required for molecules, such as nutrients or drugs to travel from the microchannel to a given depth into the cavity. These analytical predictions can facilitate the rational design of microfluidic devices to optimize and maintain long-term, physiologically-based culture conditions with low fluid shear stress.

Ionic electroactive polymer actuators as active microfluidic mixers

DOE PAGES

Meis, Catherine; Montazami, Reza; Hashemi, Nastaran

2015-11-06

On-chip sample processing is integral to the continued development of lab-on-a-chip devices for various applications. An active microfluidic mixer prototype is proposed using ionic electroactive polymer actuators (IEAPAs) as artificial cilia. A proof-of-concept experiment was performed in which the actuators were shown to produce localized flow pattern disruptions in the laminar flow regime. Suggestions for further engineering and optimization of a scaled-down, complete device are provided. Furthermore, the device in its current state of development necessitates further engineering, the use of IEAPAs addresses issues currently associated with the use of electromechanical actuators as active microfluidic mixers and may prove tomore » be a useful alternative to other similar materials.« less

Review of Recent Metamaterial Microfluidic Sensors

PubMed Central

Salim, Ahmed

2018-01-01

Metamaterial elements/arrays exhibit a sensitive response to fluids yet with a small footprint, therefore, they have been an attractive choice to realize various sensing devices when integrated with microfluidic technology. Micro-channels made from inexpensive biocompatible materials avoid any contamination from environment and require only microliter–nanoliter sample for sensing. Simple design, easy fabrication process, light weight prototype, and instant measurements are advantages as compared to conventional (optical, electrochemical and biological) sensing systems. Inkjet-printed flexible sensors find their utilization in rapidly growing wearable electronics and health-monitoring flexible devices. Adequate sensitivity and repeatability of these low profile microfluidic sensors make them a potential candidate for point-of-care testing which novice patients can use reliably. Aside from degraded sensitivity and lack of selectivity in all practical microwave chemical sensors, they require an instrument, such as vector network analyzer for measurements and not readily available as a self-sustained portable sensor. This review article presents state-of-the-art metamaterial inspired microfluidic bio/chemical sensors (passive devices ranging from gigahertz to terahertz range) with an emphasis on metamaterial sensing circuit and microfluidic detection. We also highlight challenges and strategies to cope these issues which set future directions. PMID:29342953

Review of Recent Metamaterial Microfluidic Sensors.

PubMed

Salim, Ahmed; Lim, Sungjoon

2018-01-15

Metamaterial elements/arrays exhibit a sensitive response to fluids yet with a small footprint, therefore, they have been an attractive choice to realize various sensing devices when integrated with microfluidic technology. Micro-channels made from inexpensive biocompatible materials avoid any contamination from environment and require only microliter-nanoliter sample for sensing. Simple design, easy fabrication process, light weight prototype, and instant measurements are advantages as compared to conventional (optical, electrochemical and biological) sensing systems. Inkjet-printed flexible sensors find their utilization in rapidly growing wearable electronics and health-monitoring flexible devices. Adequate sensitivity and repeatability of these low profile microfluidic sensors make them a potential candidate for point-of-care testing which novice patients can use reliably. Aside from degraded sensitivity and lack of selectivity in all practical microwave chemical sensors, they require an instrument, such as vector network analyzer for measurements and not readily available as a self-sustained portable sensor. This review article presents state-of-the-art metamaterial inspired microfluidic bio/chemical sensors (passive devices ranging from gigahertz to terahertz range) with an emphasis on metamaterial sensing circuit and microfluidic detection. We also highlight challenges and strategies to cope these issues which set future directions.

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

PubMed

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

2016-06-20

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.

Isolation of Circulating Plasma Cells in Multiple Myeloma Using CD138 Antibody-Based Capture in a Microfluidic Device

NASA Astrophysics Data System (ADS)

Qasaimeh, Mohammad A.; Wu, Yichao C.; Bose, Suman; Menachery, Anoop; Talluri, Srikanth; Gonzalez, Gabriel; Fulciniti, Mariateresa; Karp, Jeffrey M.; Prabhala, Rao H.; Karnik, Rohit

2017-04-01

The necessity for bone marrow aspiration and the lack of highly sensitive assays to detect residual disease present challenges for effective management of multiple myeloma (MM), a plasma cell cancer. We show that a microfluidic cell capture based on CD138 antigen, which is highly expressed on plasma cells, permits quantitation of rare circulating plasma cells (CPCs) in blood and subsequent fluorescence-based assays. The microfluidic device is based on a herringbone channel design, and exhibits an estimated cell capture efficiency of ~40-70%, permitting detection of <10 CPCs/mL using 1-mL sample volumes, which is difficult using existing techniques. In bone marrow samples, the microfluidic-based plasma cell counts exhibited excellent correlation with flow cytometry analysis. In peripheral blood samples, the device detected a baseline of 2-5 CD138+ cells/mL in healthy donor blood, with significantly higher numbers in blood samples of MM patients in remission (20-24 CD138+ cells/mL), and yet higher numbers in MM patients exhibiting disease (45-184 CD138+ cells/mL). Analysis of CPCs isolated using the device was consistent with serum immunoglobulin assays that are commonly used in MM diagnostics. These results indicate the potential of CD138-based microfluidic CPC capture as a useful ‘liquid biopsy’ that may complement or partially replace bone marrow aspiration.

How to fabricate robust microfluidic systems for a dollar

NASA Astrophysics Data System (ADS)

Lapierre, Florian; Cameron, Neil R.; Oakeshott, John; Peat, Thomas; Zhu, Yonggang

2013-12-01

Since the past decade, the interest towards microfluidic devices has sensibly grown due to the wide variety of multidisciplinary applications. One branch of the microfluidic domain consists in the synthesis of various types of emulsions requested by cosmetic, food and biotechnological industries In particular, monodisperse water-in-oil microemulsion synthetised in microfluidic devices are quickly becoming the new generation of emulsions for precise bead control and high surface area. These microemulsions are generally aqueous bioreactors in the form of droplets from 500 nm to 10 μm in diameter, enclosed in an oil environment. An increasing demand for bigger emulsions has led us to investigate new techniques for fabricating fluidic devices allowing a better control over the final size of the droplets. An easy, cheap, reproducible and fast technology for generating emulsions in the range of 100s μm with high throughout (up to mL/h) is reported. Simply using pipette tips and tubing, an innovative microfluidic device was fabricated, able to synthetise water-in-oil emulsions within the range 50 - 500 _μm and double emulsions. These new emulsions are currently used for the synthesis of highly porous polymers beads from High Internal Phase Emulsion (HIPE). These beads will find high potential in 3D cell culture due to their high porosity (up to 90%) and pore size (from 5 to 30μm).

A “dry and wet hybrid” lithography technique for multilevel replication templates: Applications to microfluidic neuron culture and two-phase global mixing

PubMed Central

Paul, Debjani; Saias, Laure; Pedinotti, Jean-Cedric; Chabert, Max; Magnifico, Sebastien; Pallandre, Antoine; De Lambert, Bertrand; Houdayer, Claude; Brugg, Bernard; Peyrin, Jean-Michel; Viovy, Jean-Louis

2011-01-01

A broad range of microfluidic applications, ranging from cell culture to protein crystallization, requires multilevel devices with different heights and feature sizes (from micrometers to millimeters). While state-of-the-art direct-writing techniques have been developed for creating complex three-dimensional shapes, replication molding from a multilevel template is still the preferred method for fast prototyping of microfluidic devices in the laboratory. Here, we report on a “dry and wet hybrid” technique to fabricate multilevel replication molds by combining SU-8 lithography with a dry film resist (Ordyl). We show that the two lithography protocols are chemically compatible with each other. Finally, we demonstrate the hybrid technique in two different microfluidic applications: (1) a neuron culture device with compartmentalization of different elements of a neuron and (2) a two-phase (gas-liquid) global micromixer for fast mixing of a small amount of a viscous liquid into a larger volume of a less viscous liquid. PMID:21559239

Microfluidic devices for the isolation of circulating rare cells: a focus on affinity-based, dielectrophoresis, and hydrophoresis.

PubMed

Hyun, Kyung-A; Jung, Hyo-Il

2013-04-01

Circulating rare cells have attracted interest because they can be good indicators of various types of diseases. For example, enumeration of circulating tumor cells is used for cancer diagnosis and prognosis, while DNA analysis or enumeration of nucleated red blood cells is useful for prenatal diagnosis or hypoxic anemia, and that of circulating stem cells to diagnose cancer metastasis. Isolation of these cells and their downstream analyses can provide significant information such as the origin and characteristics of a disease. Novel approaches based on microfluidics have many advantages, including the continuous process and integration with other components for analysis. For these reasons, a variety of microfluidic devices have been developed to isolate and characterize rare cells. In this article, we review several microfluidic devices, with a focus on affinity-based isolation (e.g. antigen-antibody reaction) and label-free separation (DEP and hydrophoresis). © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Validation of long-term primary neuronal cultures and network activity through the integration of reversibly bonded microbioreactors and MEA substrates.

PubMed

Biffi, Emilia; Menegon, Andrea; Piraino, Francesco; Pedrocchi, Alessandra; Fiore, Gianfranco B; Rasponi, Marco

2012-01-01

In vitro recording of neuronal electrical activity is a widely used technique to understand brain functions and to study the effect of drugs on the central nervous system. The integration of microfluidic devices with microelectrode arrays (MEAs) enables the recording of networks activity in a controlled microenvironment. In this work, an integrated microfluidic system for neuronal cultures was developed, reversibly coupling a PDMS microfluidic device with a commercial flat MEA through magnetic forces. Neurons from mouse embryos were cultured in a 100 µm channel and their activity was followed up to 18 days in vitro. The maturation of the networks and their morphological and functional characteristics were comparable with those of networks cultured in macro-environments and described in literature. In this work, we successfully demonstrated the ability of long-term culturing of primary neuronal cells in a reversible bonded microfluidic device (based on magnetism) that will be fundamental for neuropharmacological studies. Copyright © 2011 Wiley Periodicals, Inc.

A Microfluidic Cell Concentrator

PubMed Central

Warrick, Jay; Casavant, Ben; Frisk, Megan; Beebe, David

2010-01-01

Cell concentration via centrifugation is a ubiquitous step in many cell culture procedures. At the macroscale, centrifugation suffers from a number of limitations particularly when dealing with small numbers of cells (e.g., less than 50,000). On the other hand, typical microscale methods for cell concentration can affect cell physiology and bias readouts of cell behavior and function. In this paper, we present a microfluidic concentrator device that utilizes the effects of gravity to allow cells to gently settle out of a suspension into a collection region without the use of specific adhesion ligands. Dimensional analysis was performed to compare different device designs and was verified with flow modeling to optimize operational parameters. We are able to concentrate low-density cell suspensions in a microfluidic chamber, achieving a cell loss of only 1.1 ± 0.6% (SD, n=7) with no observed loss during a subsequent cell staining protocol which incorporates ~36 complete device volume replacements. This method provides a much needed interface between rare cell samples and microfluidic culture assays. PMID:20843010

Finite element modeling simulation-assisted design of integrated microfluidic chips for heavy metal ion stripping analysis

NASA Astrophysics Data System (ADS)

Hong, Ying; Zou, Jianhua; Ge, Gang; Xiao, Wanyue; Gao, Ling; Shao, Jinjun; Dong, Xiaochen

2017-10-01

In this article, a transparent integrated microfluidic device composed of a 3D-printed thin-layer flow cell (3D-PTLFC) and an S-shaped screen-printed electrode (SPE) has been designed and fabricated for heavy metal ion stripping analysis. A finite element modeling (FEM) simulation is employed to optimize the shape of the electrode, the direction of the inlet pipeline, the thin-layer channel height and the sample flow rate to enhance the electron-enrichment efficiency for stripping analysis. The results demonstrate that the S-shaped SPE configuration matches the channel in 3D-PTLFC perfectly for the anodic stripping behavior of the heavy metal ions. Under optimized conditions, a wide linear range of 1-80 µg l-1 is achieved for Pb2+ detection with a limit of 0.3 µg l-1 for the microfluidic device. Thus, the obtained integrated microfluidic device proves to be a promising approach for heavy metal ions stripping analysis with low cost and high performance.

Magnetically-guided assembly of microfluidic fibers for ordered construction of diverse netlike modules

NASA Astrophysics Data System (ADS)

Li, Xingfu; Shi, Qing; Wang, Huaping; Sun, Tao; Huang, Qiang; Fukuda, Toshio

2017-12-01

In this paper, a magnetically-guided assembly method is proposed to methodically construct diverse modules with a microfiber-based network for promoting nutrient circulation and waste excretion of cell culture. The microfiber is smoothly spun from the microfluidic device via precise control of the volumetric flow rate, and superparamagnetic nanoparticles within the alginate solution of the microfluidic fiber enable its magnetic response. The magnetized device is used to effectively capture the microfiber using its powerful magnetic flux density and high magnetic field gradient. Subsequently, the dot-matrix magnetic flux density is used to distribute the microfibers in an orderly fashion that depends on the array structure of the magnetized device. Furthermore, the magnetic microfluidic fibers are spatially organized into desired locations and are cross-aligned to form highly interconnected netlike modules in a liquid environment. Therefore, the experimental results herein demonstrate the structural controllability and stability of various modules and establish the effectiveness of the proposed method.

Culture and Sampling of Primary Adipose Tissue in Practical Microfluidic Systems.

PubMed

Brooks, Jessica C; Judd, Robert L; Easley, Christopher J

2017-01-01

Microfluidic culture of primary adipose tissue allows for reduced sample and reagent volumes as well as constant media perfusion of the cells. By continuously flowing media over the tissue, microfluidic sampling systems can more accurately mimic vascular flow in vivo. Quantitative measurements can be performed on or off chip to provide time-resolved secretion data, furthering insight into the dynamics of the function of adipose tissue. Buoyancy resulting from the large lipid storage capacity in this tissue presents a unique challenge for culture, and it is important to account for this buoyancy during microdevice design. Herein, we describe approaches for microfluidic device fabrication that utilize 3D-printed interface templating to help counteract cell buoyancy. We apply such methods to the culture of both isolated, dispersed primary adipocytes and epididymal adipose explants. To facilitate more widespread adoption of the methodology, the devices presented here are designed for user-friendly operation. Only handheld syringes are needed to control flow, and devices are inexpensive and disposable.

Dissolved oxygen sensing using organometallic dyes deposited within a microfluidic environment

NASA Astrophysics Data System (ADS)

Chen, Q. L.; Ho, H. P.; Jin, L.; Chu, B. W.-K.; Li, M. J.; Yam, V. W.-W.

2008-02-01

This work primarily aims to integrate dissolved oxygen sensing capability with a microfluidic platform containing arrays of micro bio-reactors or bio-activity indicators. The measurement of oxygen concentration is of significance for a variety of bio-related applications such as cell culture and gene expression. Optical oxygen sensors based on luminescence quenching are gaining much interest in light of their low power consumption, quick response and high analyte sensitivity in comparison to similar oxygen sensing devices. In our microfluidic oxygen sensor device, a thin layer of oxygen-sensitive luminescent organometallic dye is covalently bonded to a glass slide. Micro flow channels are formed on the glass slide using patterned PDMS (Polydimethylsiloxane). Dissolved oxygen sensing is then performed by directing an optical excitation probe beam to the area of interest within the microfluidic channel. The covalent bonding approach for sensor layer formation offers many distinct advantages over the physical entrapment method including minimizing dye leaching, ensuring good stability and fabrication simplicity. Experimental results confirm the feasibility of the device.

An optimized resistor pattern for temperature gradient control in microfluidics

NASA Astrophysics Data System (ADS)

Selva, Bertrand; Marchalot, Julien; Jullien, Marie-Caroline

2009-06-01

In this paper, we demonstrate the possibility of generating high-temperature gradients with a linear temperature profile when heating is provided in situ. Thanks to improved optimization algorithms, the shape of resistors, which constitute the heating source, is optimized by applying the genetic algorithm NSGA-II (acronym for the non-dominated sorting genetic algorithm) (Deb et al 2002 IEEE Trans. Evol. Comput. 6 2). Experimental validation of the linear temperature profile within the cavity is carried out using a thermally sensitive fluorophore, called Rhodamine B (Ross et al 2001 Anal. Chem. 73 4117-23, Erickson et al 2003 Lab Chip 3 141-9). The high level of agreement obtained between experimental and numerical results serves to validate the accuracy of this method for generating highly controlled temperature profiles. In the field of actuation, such a device is of potential interest since it allows for controlling bubbles or droplets moving by means of thermocapillary effects (Baroud et al 2007 Phys. Rev. E 75 046302). Digital microfluidics is a critical area in the field of microfluidics (Dreyfus et al 2003 Phys. Rev. Lett. 90 14) as well as in the so-called lab-on-a-chip technology. Through an example, the large application potential of such a technique is demonstrated, which entails handling a single bubble driven along a cavity using simple and tunable embedded resistors.

Simple Check Valves for Microfluidic Devices

NASA Technical Reports Server (NTRS)

Willis, Peter A.; Greer, Harold F.; Smith, J. Anthony

2010-01-01

A simple design concept for check valves has been adopted for microfluidic devices that consist mostly of (1) deformable fluorocarbon polymer membranes sandwiched between (2) borosilicate float glass wafers into which channels, valve seats, and holes have been etched. The first microfluidic devices in which these check valves are intended to be used are micro-capillary electrophoresis (microCE) devices undergoing development for use on Mars in detecting compounds indicative of life. In this application, it will be necessary to store some liquid samples in reservoirs in the devices for subsequent laboratory analysis, and check valves are needed to prevent cross-contamination of the samples. The simple check-valve design concept is also applicable to other microfluidic devices and to fluidic devices in general. These check valves are simplified microscopic versions of conventional rubber- flap check valves that are parts of numerous industrial and consumer products. These check valves are fabricated, not as separate components, but as integral parts of microfluidic devices. A check valve according to this concept consists of suitably shaped portions of a deformable membrane and the two glass wafers between which the membrane is sandwiched (see figure). The valve flap is formed by making an approximately semicircular cut in the membrane. The flap is centered over a hole in the lower glass wafer, through which hole the liquid in question is intended to flow upward into a wider hole, channel, or reservoir in the upper glass wafer. The radius of the cut exceeds the radius of the hole by an amount large enough to prevent settling of the flap into the hole. As in a conventional rubber-flap check valve, back pressure in the liquid pushes the flap against the valve seat (in this case, the valve seat is the adjacent surface of the lower glass wafer), thereby forming a seal that prevents backflow.

A microfluidic platform for 3-dimensional cell culture and cell-based assays.

PubMed

Kim, Minseok S; Yeon, Ju Hun; Park, Je-Kyun

2007-02-01

This paper reports a novel microfluidic platform introducing peptide hydrogel to make biocompatible microenvironment as well as realizing in situ cell-based assays. Collagen composite, OPLA and Puramatrix scaffolds are compared to select good environment for human hepatocellular carcinoma cells (HepG2) by albumin measurement. The selected biocompatible self-assembling peptide hydrogel, Puramatrix, is hydrodynamically focused in the middle of main channel of a microfluidic device, and at the same time the cells are 3-dimensionally immobilized and encapsulated without any additional surface treatment. HepG2 cells have been 3-dimensionally cultured in a poly(dimethylsiloxane) (PDMS) microfluidic device for 4 days. The cells cultured in micro peptide scaffold are compared with those cultured by conventional petri dish in morphology and the rate of albumin secretion. By injection of different reagents into either side of the peptide scaffold, the microfluidic device also forms a linear concentration gradient profile across the peptide scaffold due to molecular diffusion. Based on this characteristic, toxicity tests are performed by Triton X-100. As the higher toxicant concentration gradient forms, the wider dead zone of cells in the peptide scaffold represents. This microfluidic platform facilitates in vivo-like 3-dimensional microenvironment, and have a potential for the applications of reliable cell-based screening and assays including cytotoxicity test, real-time cell viability monitoring, and continuous dose-response assay.

Label-free quantitation of peptide release from neurons in a microfluidic device with mass spectrometry imaging

PubMed Central

Zhong, Ming; Lee, Chang Young; Croushore, Callie A.; Sweedler, Jonathan V.

2013-01-01

Microfluidic technology allows the manipulation of mass-limited samples and when used with cultured cells, enables control of the extracellular microenvironment, making it well suited for studying neurons and their response to environmental perturbations. While matrix-assisted laser desorption/ionization (MALDI) mass spectrometry (MS) provides for off-line coupling to microfluidic devices for characterizing small-volume extracellular releasates, performing quantitative studies with MALDI is challenging. Here we describe a label-free absolute quantitation approach for microfluidic devices. We optimize device fabrication to prevent analyte losses before measurement and then incorporate a substrate that collects the analytes as they flow through a collection channel. Following collection, the channel is interrogated using MS imaging. Rather than quantifying the sample present via MS peak height, the length of the channel containing appreciable analyte signal is used as a measure of analyte amount. A linear relationship between peptide amount and band length is suggested by modeling the adsorption process and this relationship is validated using two neuropeptides, acidic peptide (AP) and α-bag cell peptide [1-9] (αBCP). The variance of length measurement, defined as the ratio of standard error to mean value, is as low as 3% between devices. The limit of detection (LOD) of our system is 600 fmol for AP and 400 fmol for αBCP. Using appropriate calibrations, we determined that an individual Aplysia bag cell neuron secretes 0.15 ± 0.03 pmol of AP and 0.13 ± 0.06 pmol of αBCP after being stimulated with elevated KCl. This quantitation approach is robust, does not require labeling, and is well suited for miniaturized off-line characterization from microfluidic devices. PMID:22508372

Light-Addressable Measurement of in Vivo Tissue Oxygenation in an Unanesthetized Zebrafish Embryo via Phase-Based Phosphorescence Lifetime Detection

PubMed Central

Huang, Shih-Hao; Yu, Chu-Hung; Chien, Yi-Lung

2015-01-01

We have developed a digital light modulation system that utilizes a modified commercial projector equipped with a laser diode as a light source for quantitative measurements of in vivo tissue oxygenation in an unanesthetized zebrafish embryo via phase-based phosphorescence lifetime detection. The oxygen-sensitive phosphorescent probe (Oxyphor G4) was first inoculated into the bloodstream of 48 h post-fertilization (48 hpf) zebrafish embryos via the circulation valley to rapidly disperse probes throughout the embryo. The unanesthetized zebrafish embryo was introduced into the microfluidic device and immobilized on its lateral side by using a pneumatically actuated membrane. By controlling the illumination pattern on the digital micromirror device in the projector, the modulated excitation light can be spatially projected to illuminate arbitrarily-shaped regions of tissue of interest for in vivo oxygen measurements. We have successfully measured in vivo oxygen changes in the cardiac region and cardinal vein of a 48 hpf zebrafish embryo that experience hypoxia and subsequent normoxic conditions. Our proposed platform provides the potential for the real-time investigation of oxygen distribution in tissue microvasculature that relates to physiological stimulation and diseases in a developing organism. PMID:25856326

Multiplexed microfluidic approach for nucleic acid enrichment

DOEpatents

VanderNoot, Victoria A.; Langevin, Stanley Alan; Bent, Zachary; Renzi, Ronald F.; Ferko, Scott M.; Van De Vreugde, James L.; Lane, Todd; Patel, Kamlesh; Branda, Steven

2016-04-26

A system for enhancing a nucleic acid sample may include a one pump, a denaturing chamber; a microfluidic hydroxyapatite chromatography device configured for performing hydroxyapatite chromatography on the nucleic acid sample, a sample collector, and tubing connecting the pump with the denaturing chamber, the hydroxyapatite chromatography device and the sample collector such that the pump may be used to move the nucleic acid sample from the denaturing chamber to the hydroxyapatite chromatography device and then to the sample collector.

Design of a compact microfludic device for controllable cell distribution.

PubMed

Li, Jing-Liang; Day, Daniel; Gu, Min

2010-11-21

A compact microfluidic device with 96 microchambers allocated within four circular units was designed and examined for cell distribution. In each unit, cells were distributed to the surrounding chambers radially from the center. The circular arrangement of the chambers makes the design simple and compact. A controllable and quantitative cell distribution is achievable in this device. This design is significant to the microfluidic applications where controllable distribution of cells in multipule microchambers is demanded.

Effects of hydraulic pressure on cardiomyoblasts in a microfluidic device.

PubMed

Hsiao, Yu-Fang; Pan, Huei-Jyuan; Tung, Yi-Chung; Chen, Chien-Chang; Lee, Chau-Hwang

2015-03-01

We employed a microfluidic device to study the effects of hydraulic pressure on cardiomyoblast H9c2. The 170 mm Hg pressure increased the cellular area and the expression of atrial natriuretic peptide. With the same device, we demonstrated that the effects of hydraulic pressure on the cardiomyoblast could be reduced by the inhibitor of focal adhesion kinase. This mechanical-chemical antagonism could lead to a potential therapeutic strategy of hypertension-induced cardiac hypertrophy.

Isolation and detection of circulating tumour cells from metastatic melanoma patients using a slanted spiral microfluidic device.

PubMed

Aya-Bonilla, Carlos A; Marsavela, Gabriela; Freeman, James B; Lomma, Chris; Frank, Markus H; Khattak, Muhammad A; Meniawy, Tarek M; Millward, Michael; Warkiani, Majid E; Gray, Elin S; Ziman, Mel

2017-09-15

Circulating Tumour Cells (CTCs) are promising cancer biomarkers. Several methods have been developed to isolate CTCs from blood samples. However, the isolation of melanoma CTCs is very challenging as a result of their extraordinary heterogeneity, which has hindered their biological and clinical study. Thus, methods that isolate CTCs based on their physical properties, rather than surface marker expression, such as microfluidic devices, are greatly needed in melanoma. Here, we assessed the ability of the slanted spiral microfluidic device to isolate melanoma CTCs via label-free enrichment. We demonstrated that this device yields recovery rates of spiked melanoma cells of over 80% and 55%, after one or two rounds of enrichment, respectively. Concurrently, a two to three log reduction of white blood cells was achieved with one or two rounds of enrichment, respectively. We characterised the isolated CTCs using multimarker flow cytometry, immunocytochemistry and gene expression. The results demonstrated that CTCs from metastatic melanoma patients were highly heterogeneous and commonly expressed stem-like markers such as PAX3 and ABCB5. The implementation of the slanted microfluidic device for melanoma CTC isolation enables further understanding of the biology of melanoma metastasis for biomarker development and to inform future treatment approaches.

Automated microfluidic devices integrating solid-phase extraction, fluorescent labeling, and microchip electrophoresis for preterm birth biomarker analysis.

PubMed

Sahore, Vishal; Sonker, Mukul; Nielsen, Anna V; Knob, Radim; Kumar, Suresh; Woolley, Adam T

2018-01-01

We have developed multichannel integrated microfluidic devices for automated preconcentration, labeling, purification, and separation of preterm birth (PTB) biomarkers. We fabricated multilayer poly(dimethylsiloxane)-cyclic olefin copolymer (PDMS-COC) devices that perform solid-phase extraction (SPE) and microchip electrophoresis (μCE) for automated PTB biomarker analysis. The PDMS control layer had a peristaltic pump and pneumatic valves for flow control, while the PDMS fluidic layer had five input reservoirs connected to microchannels and a μCE system. The COC layers had a reversed-phase octyl methacrylate porous polymer monolith for SPE and fluorescent labeling of PTB biomarkers. We determined μCE conditions for two PTB biomarkers, ferritin (Fer) and corticotropin-releasing factor (CRF). We used these integrated microfluidic devices to preconcentrate and purify off-chip-labeled Fer and CRF in an automated fashion. Finally, we performed a fully automated on-chip analysis of unlabeled PTB biomarkers, involving SPE, labeling, and μCE separation with 1 h total analysis time. These integrated systems have strong potential to be combined with upstream immunoaffinity extraction, offering a compact sample-to-answer biomarker analysis platform. Graphical abstract Pressure-actuated integrated microfluidic devices have been developed for automated solid-phase extraction, fluorescent labeling, and microchip electrophoresis of preterm birth biomarkers.

Synthesis and cell-free cloning of DNA libraries using programmable microfluidics

PubMed Central

Yehezkel, Tuval Ben; Rival, Arnaud; Raz, Ofir; Cohen, Rafael; Marx, Zipora; Camara, Miguel; Dubern, Jean-Frédéric; Koch, Birgit; Heeb, Stephan; Krasnogor, Natalio; Delattre, Cyril; Shapiro, Ehud

2016-01-01

Microfluidics may revolutionize our ability to write synthetic DNA by addressing several fundamental limitations associated with generating novel genetic constructs. Here we report the first de novo synthesis and cell-free cloning of custom DNA libraries in sub-microliter reaction droplets using programmable digital microfluidics. Specifically, we developed Programmable Order Polymerization (POP), Microfluidic Combinatorial Assembly of DNA (M-CAD) and Microfluidic In-vitro Cloning (MIC) and applied them to de novo synthesis, combinatorial assembly and cell-free cloning of genes, respectively. Proof-of-concept for these methods was demonstrated by programming an autonomous microfluidic system to construct and clone libraries of yeast ribosome binding sites and bacterial Azurine, which were then retrieved in individual droplets and validated. The ability to rapidly and robustly generate designer DNA molecules in an autonomous manner should have wide application in biological research and development. PMID:26481354

Fabricating PFPE Membranes for Microfluidic Valves and Pumps

NASA Technical Reports Server (NTRS)

Greer, Frank; White, Victor E.; Lee, Michael C.; Willis, Peter A.; Grunthaner, Frank J.; Rolland, Jason; Rolland, Jason

2009-01-01

A process has been developed for fabricating membranes of a perfluoropolyether (PFPE) and integrating them into valves and pumps in laboratory-on-achip microfluidic devices. Membranes of poly(tetrafluoroethylene) [PTFE] and poly(dimethylsilane) [PDMS] have been considered for this purpose and found wanting. By making it possible to use PFPE instead of PTFE or PDMS, the present process expands the array of options for further development of microfluidic devices for diverse applications that could include detection of biochemicals of interest, detection of toxins and biowarfare agents, synthesis and analysis of proteins, medical diagnosis, and synthesis of fuels.

Conductivity detection for monitoring mixing reactions in microfluidic devices.

PubMed

Liu, Y; Wipf, D O; Henry, C S

2001-08-01

A conductivity detector was coupled to poly(dimethylsiloxane)-glass capillary electrophoresis microchips to monitor microfluidic flow. Electroosmotic flow was investigated with both conductivity detection (CD) and the current monitoring method. No significant variation was observed between these methods, but CD showed a lower relative standard deviation. Gradient mixing experiments were employed to investigate the relationship between the electrolyte conductivity and the electrolyte concentration. A good linear response of conductivity to concentration was obtained for solutions whose difference in concentrations were less than 27 mM. The new system holds great promise for precision mixing in microfluidic devices using electrically driven flows.

Microfluidic device for acoustic cell lysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Branch, Darren W.; Cooley, Erika Jane; Smith, Gennifer Tanabe

2015-08-04

A microfluidic acoustic-based cell lysing device that can be integrated with on-chip nucleic acid extraction. Using a bulk acoustic wave (BAW) transducer array, acoustic waves can be coupled into microfluidic cartridges resulting in the lysis of cells contained therein by localized acoustic pressure. Cellular materials can then be extracted from the lysed cells. For example, nucleic acids can be extracted from the lysate using silica-based sol-gel filled microchannels, nucleic acid binding magnetic beads, or Nafion-coated electrodes. Integration of cell lysis and nucleic acid extraction on-chip enables a small, portable system that allows for rapid analysis in the field.

Fabrication, modification, and application of poly(methyl methacrylate) microfluidic chips.

PubMed

Chen, Yun; Zhang, Luyan; Chen, Gang

2008-05-01

Poly(methyl methacrylate) (PMMA) is particularly useful for microfluidic chips with the features of low price, excellent optic transparency, attractive mechanical and chemical properties, ease of fabrication and modification, biocompatibility, etc. During the past decade, significant progress in the PMMA microfluidic chips has occurred. This review, which contains 120 references, summarizes the recent advances and the key strategies in the fabrication, modification, and application of PMMA microfluidic chips. It is expected that PMMA microchips should find a wide range of applications and will lead to the creation of truly disposable microfluidic devices.

Simple and inexpensive micromachined aluminum microfluidic devices for acoustic focusing of particles and cells.

PubMed

Gautam, Gayatri P; Burger, Tobias; Wilcox, Andrew; Cumbo, Michael J; Graves, Steven W; Piyasena, Menake E

2018-05-01

We introduce a new method to construct microfluidic devices especially useful for bulk acoustic wave (BAW)-based manipulation of cells and microparticles. To obtain efficient acoustic focusing, BAW devices require materials that have high acoustic impedance mismatch relative to the medium in which the cells/microparticles are suspended and materials with a high-quality factor. To date, silicon and glass have been the materials of choice for BAW-based acoustofluidic channel fabrication. Silicon- and glass-based fabrication is typically performed in clean room facilities, generates hazardous waste, and can take several hours to complete the microfabrication. To address some of the drawbacks in fabricating conventional BAW devices, we explored a new approach by micromachining microfluidic channels in aluminum substrates. Additionally, we demonstrate plasma bonding of poly(dimethylsiloxane) (PDMS) onto micromachined aluminum substrates. Our goal was to achieve an approach that is both low cost and effective in BAW applications. To this end, we micromachined aluminum 6061 plates and enclosed the systems with a thin PDMS cover layer. These aluminum/PDMS hybrid microfluidic devices use inexpensive materials and are simply constructed outside a clean room environment. Moreover, these devices demonstrate effectiveness in BAW applications as demonstrated by efficient acoustic focusing of polystyrene microspheres, bovine red blood cells, and Jurkat cells and the generation of multiple focused streams in flow-through systems. Graphical abstract The aluminum acoustofluidic device and the generation of multinode focusing of particles.

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

Microfluidic mixing triggered by an external LED illumination.

PubMed

Venancio-Marques, Anna; Barbaud, Fanny; Baigl, Damien

2013-02-27

The mixing of confined liquids is a central yet challenging operation in miniaturized devices. Microfluidic mixing is usually achieved with passive mixers that are robust but poorly flexible, or active mixers that offer dynamic control but mainly rely on electrical or mechanical transducers, which increase the fragility, cost, and complexity of the device. Here, we describe the first remote and reversible control of microfluidic mixing triggered by a light illumination simply provided by an external LED illumination device. The approach is based on the light-induced generation of water microdroplets acting as reversible stirrers of two continuous oil phase flows containing samples to be mixed. We demonstrate many cycles of reversible photoinduced transitions between a nonmixing behavior and full homogenization of the two oil phases. The method is cheap, portable, and adaptable to many device configurations, thus constituting an essential brick for the generation of future all-optofluidic chip.

Stem cell culture and differentiation in microfluidic devices toward organ-on-a-chip.

PubMed

Zhang, Jie; Wei, Xiaofeng; Zeng, Rui; Xu, Feng; Li, XiuJun

2017-06-01

Microfluidic lab-on-a-chip provides a new platform with unique advantages to mimic complex physiological microenvironments in vivo and has been increasingly exploited to stem cell research. In this review, we highlight recent advances of microfluidic devices for stem cell culture and differentiation toward the development of organ-on-a-chip, especially with an emphasis on vital innovations within the last 2 years. Various aspects for improving on-chip stem-cell culture and differentiation, particularly toward organ-on-a-chip, are discussed, along with microenvironment control, surface modification, extracellular scaffolds, high throughput and stimuli. The combination of microfluidic technologies and stem cells hold great potential toward versatile systems of 'organ-on-a-chip' as desired. Adapted with permission from [1-8].

Sensitive and inexpensive digital DNA analysis by microfluidic enrichment of rolling circle amplified single-molecules

PubMed Central

Kühnemund, Malte; Hernández-Neuta, Iván; Sharif, Mohd Istiaq; Cornaglia, Matteo; Gijs, Martin A.M.

2017-01-01

Abstract Single molecule quantification assays provide the ultimate sensitivity and precision for molecular analysis. However, most digital analysis techniques, i.e. droplet PCR, require sophisticated and expensive instrumentation for molecule compartmentalization, amplification and analysis. Rolling circle amplification (RCA) provides a simpler means for digital analysis. Nevertheless, the sensitivity of RCA assays has until now been limited by inefficient detection methods. We have developed a simple microfluidic strategy for enrichment of RCA products into a single field of view of a low magnification fluorescent sensor, enabling ultra-sensitive digital quantification of nucleic acids over a dynamic range from 1.2 aM to 190 fM. We prove the broad applicability of our analysis platform by demonstrating 5-plex detection of as little as ∼1 pg (∼300 genome copies) of pathogenic DNA with simultaneous antibiotic resistance marker detection, and the analysis of rare oncogene mutations. Our method is simpler, more cost-effective and faster than other digital analysis techniques and provides the means to implement digital analysis in any laboratory equipped with a standard fluorescent microscope. PMID:28077562

Single cell Enrichment with High Throughput Microfluidic Devices

NASA Astrophysics Data System (ADS)

Pakjesm Pourfard, Pedram

Microfluidics is a rapidly growing field of biomedical engineering with numerous applications such as diagnostic testing, therapeutics, and research preparation. Cell enrichment for automated diagnostic is often assayed through measurement of biochemical and biophysical markers. Although biochemical markers have been widely used, intrinsic biophysical markers, such as, Shear migration, Lift force, Dean force, and many other label-free techniques, are advantageous since they don't require costly labeling or sample preparation. However, current passive techniques for enrichment had limited adoption in clinical and cell biology research applications. They generally require low flow rate and low cell volume fraction for high efficiency. The Control increment filtration, T-shaped microfluidic device, and spiral-shaped microfluidic devices will be studied for single-cell separation from aggregates. Control increment filtration works like the tangential filter; however, cells are separated based off of same amount of flow rate passing through large space gaps. Main microchannel of T-Shaped is connected to two perpendicular side channels. Based off Shear-modulated inertial migration, this device will enable selective enrichment of cells. The spiral shaped microfluidic device depends on different Dean and lift forces acting on cells to separate them based off different sizes. The spiral geometry of the microchannel will enable dominant inertial forces and the Dean Rotation force to cause larger cells to migrate to the inner side of the microchannel. Because manipulation of microchannel dimensions correlates to the degree of cell separation, versatility in design exists. Cell mixture samples will contain cells of different sizes and therefore design strategies could be utilized to maximize the effectiveness of single-cell separation.

Use of Ice-Nucleating Proteins To Improve the Performance of Freeze-Thaw Valves in Microfluidic Devices.

PubMed

Gaiteri, Joseph C; Henley, W Hampton; Siegfried, Nathan A; Linz, Thomas H; Ramsey, J Michael

2017-06-06

Currently, reliable valving on integrated microfluidic devices fabricated from rigid materials is confined to expensive and complex methods. Freeze-thaw valves (FTVs) can provide a low cost, low complexity valving mechanism, but reliable implementation of them has been greatly hindered by the lack of ice nucleation sites within the valve body's small volume. Work to date has required very low temperatures (on the order of -40 °C or colder) to induce freezing without nucleation sites, making FTVs impractical due to instrument engineering challenges. Here, we report the use of ice-nucleating proteins (INPs) to induce ice formation at relatively warm temperatures in microfluidic devices. Microfluidic channels were filled with buffers containing femtomolar INP concentrations from Pseudomonas syringae. The channels were cooled externally with simple, small-footprint Peltier thermoelectric coolers (TECs), and the times required for channel freezing (valve closure) and thawing (valve opening) were measured. Under optimized conditions in plastic chips, INPs made sub-10 s actuations possible at TEC temperatures as warm as -13 °C. Additionally, INPs were found to have no discernible inhibitory effects in model enzyme-linked immunosorbent assays or polymerase chain reactions, indicating their compatibility with microfluidic systems that incorporate these widely used bioassays. FTVs with INPs provide a much needed reliable valving scheme for rigid plastic devices with low complexity, low cost, and no moving parts on the device or instrument. The reduction in freeze time, accessible actuation temperatures, chemical compatibility, and low complexity make the implementation of compact INP-based FTV arrays practical and attractive for the control of integrated biochemical assays.

Integrative Utilization of Microenvironments, Biomaterials and Computational Techniques for Advanced Tissue Engineering.

PubMed

Shamloo, Amir; Mohammadaliha, Negar; Mohseni, Mina

2015-10-20

This review aims to propose the integrative implementation of microfluidic devices, biomaterials, and computational methods that can lead to a significant progress in tissue engineering and regenerative medicine researches. Simultaneous implementation of multiple techniques can be very helpful in addressing biological processes. Providing controllable biochemical and biomechanical cues within artificial extracellular matrix similar to in vivo conditions is crucial in tissue engineering and regenerative medicine researches. Microfluidic devices provide precise spatial and temporal control over cell microenvironment. Moreover, generation of accurate and controllable spatial and temporal gradients of biochemical factors is attainable inside microdevices. Since biomaterials with tunable properties are a worthwhile option to construct artificial extracellular matrix, in vitro platforms that simultaneously utilize natural, synthetic, or engineered biomaterials inside microfluidic devices are phenomenally advantageous to experimental studies in the field of tissue engineering. Additionally, collaboration between experimental and computational methods is a useful way to predict and understand mechanisms responsible for complex biological phenomena. Computational results can be verified by using experimental platforms. Computational methods can also broaden the understanding of the mechanisms behind the biological phenomena observed during experiments. Furthermore, computational methods are powerful tools to optimize the fabrication of microfluidic devices and biomaterials with specific features. Here we present a succinct review of the benefits of microfluidic devices, biomaterial, and computational methods in the case of tissue engineering and regeneration medicine. Furthermore, some breakthroughs in biological phenomena including the neuronal axon development, cancerous cell migration and blood vessel formation via angiogenesis by virtue of the aforementioned approaches are discussed. Copyright © 2015 Elsevier B.V. All rights reserved.

Hydrodynamic trapping for rapid assembly and in situ electrical characterization of droplet interface bilayer arrays

DOE PAGES

Nguyen, Mary -Anne; Srijanto, Bernadeta; Collier, C. Patrick; ...

2016-08-02

The droplet interface bilayer (DIB) is a modular technique for assembling planar lipid membranes between water droplets in oil. The DIB method thus provides a unique capability for developing digital, droplet-based membrane platforms for rapid membrane characterization, drug screening and ion channel recordings. This paper demonstrates a new, low-volume microfluidic system that automates droplet generation, sorting, and sequential trapping in designated locations to enable the rapid assembly of arrays of DIBs. The channel layout of the device is guided by an equivalent circuit model, which predicts that a serial arrangement of hydrodynamic DIB traps enables sequential droplet placement and minimizesmore » the hydrodynamic pressure developed across filled traps to prevent squeeze-through of trapped droplets. Furthermore, the incorporation of thin-film electrodes fabricated via evaporation metal deposition onto the glass substrate beneath the channels allows for the first time in situ, simultaneous electrical interrogation of multiple DIBs within a sealed device. Combining electrical measurements with imaging enables measurements of membrane capacitance and resistance and bilayer area, and our data show that DIBs formed in different trap locations within the device exhibit similar sizes and transport properties. Simultaneous, single channel recordings of ion channel gating in multiple membranes are obtained when alamethicin peptides are incorporated into the captured droplets, qualifying the thin-film electrodes as a means for measuring stimuli-responsive functions of membrane-bound biomolecules. Furthermore, this novel microfluidic-electrophysiology platform provides a reproducible, high throughput method for performing electrical measurements to study transmembrane proteins and biomembranes in low-volume, droplet-based membranes.« less

Hydrodynamic trapping for rapid assembly and in situ electrical characterization of droplet interface bilayer arrays

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nguyen, Mary -Anne; Srijanto, Bernadeta; Collier, C. Patrick

The droplet interface bilayer (DIB) is a modular technique for assembling planar lipid membranes between water droplets in oil. The DIB method thus provides a unique capability for developing digital, droplet-based membrane platforms for rapid membrane characterization, drug screening and ion channel recordings. This paper demonstrates a new, low-volume microfluidic system that automates droplet generation, sorting, and sequential trapping in designated locations to enable the rapid assembly of arrays of DIBs. The channel layout of the device is guided by an equivalent circuit model, which predicts that a serial arrangement of hydrodynamic DIB traps enables sequential droplet placement and minimizesmore » the hydrodynamic pressure developed across filled traps to prevent squeeze-through of trapped droplets. Furthermore, the incorporation of thin-film electrodes fabricated via evaporation metal deposition onto the glass substrate beneath the channels allows for the first time in situ, simultaneous electrical interrogation of multiple DIBs within a sealed device. Combining electrical measurements with imaging enables measurements of membrane capacitance and resistance and bilayer area, and our data show that DIBs formed in different trap locations within the device exhibit similar sizes and transport properties. Simultaneous, single channel recordings of ion channel gating in multiple membranes are obtained when alamethicin peptides are incorporated into the captured droplets, qualifying the thin-film electrodes as a means for measuring stimuli-responsive functions of membrane-bound biomolecules. Furthermore, this novel microfluidic-electrophysiology platform provides a reproducible, high throughput method for performing electrical measurements to study transmembrane proteins and biomembranes in low-volume, droplet-based membranes.« less

Accurate, consistent, and fast droplet splitting and dispensing in electrowetting on dielectric digital microfluidics

NASA Astrophysics Data System (ADS)

Nikapitiya, N. Y. Jagath B.; Nahar, Mun Mun; Moon, Hyejin

2017-12-01

This letter reports two novel electrode design considerations to satisfy two very important aspects of EWOD operation—(1) Highly consistent volume of generated droplets and (2) Highly improved accuracy in the generated droplet volume. Considering the design principles investigated two novel designs were proposed; L-junction electrode design to offer high throughput droplet generation and Y-junction electrode design to split a droplet very fast while maintaining equal volume of each part. Devices of novel designs were fabricated and tested, and the results are compared with those of conventional approach. It is demonstrated that inaccuracy and inconsistency of droplet volume dispensed in the device with novel electrode designs are as low as 0.17 and 0.10%, respectively, while those of conventional approach are 25 and 0.76%, respectively. The dispensing frequency is enhanced from 4 to 9 Hz by using the novel design.

Microfluidic devices connected to fused-silica capillaries with minimal dead volume.

PubMed

Bings, N H; Wang, C; Skinner, C D; Colyer, C L; Thibault, P; Harrison, D J

1999-08-01

Fused-silica capillaries have been connected to microfluidic devices for capillary electrophoresis by drilling into the edge of the device using 200-μm tungsten carbide drills. The standard pointed drill bits create a hole with a conical-shaped bottom that leads to a geometric dead volume of 0.7 nL at the junction, and significant band broadening when used with 0.2-nL sample plugs. The plate numbers obtained on the fused-silica capillary connected to the chip were about 16-25% of the predicted numbers. The conical area was removed with a flat-tipped drill bit and the band broadening was substantially eliminated (on average 98% of the predicted plate numbers were observed). All measurements were made while the device was operating with an electrospray from the end of the capillary. The effective dead volume of the flat-bottom connection is minimal and allows microfluidic devices to be connected to a wide variety of external detectors.

A microfluidic device for studying cell signaling with multiple inputs and adjustable amplitudes and frequencies

NASA Astrophysics Data System (ADS)

Ningsih, Zubaidah; Chon, James W. M.; Clayton, Andrew H. A.

2013-12-01

Cell function is largely controlled by an intricate web of macromolecular interactions called signaling networks. It is known that the type and the intensity (concentration) of stimulus affect cell behavior. However, the temporal aspect of the stimulus is not yet fully understood. Moreover, the process of distinguishing between two stimuli by a cell is still not clear. A microfluidic device enables the delivery of a precise and exact stimulus to the cell due to the laminar flow established inside its micro-channel. The slow stream delivers a constant stimulus which is adjustable according to the experiment set up. Moreover, with controllable inputs, microfluidic facilitates the stimuli delivery according to a certain pattern with adjustable amplitude, frequency and phase. Several designs of PDMS microfluidic device has been produced in this project via photolithography and soft lithography processes. To characterize the microfluidic performance, two experiments has been conducted. First, by comparing the fluorescence intensity and the lifetime of fluorescein in the present of KI, mixing extent between two inputs was observed using Frequency Lifetime Imaging Microscopy (FLIM). Furthermore, the input-output relationship of fluorescein concentration delivered was also drawn to characterize the amplitude, frequency and phase of the inputs. Second experiment involved the cell culturing inside microfluidic. Using NG108-15 cells, proliferation and differentiation were observed based on the cell number and cell physiological changes. Our results demonstrate that hurdle design gives 86% mixing of fluorescein and buffer. Relationship between inputoutput fluorescein concentrations delivered has also been demonstrated and cells were successfully cultured inside the microfluidic.

Microfluidic devices and methods including porous polymer monoliths

DOEpatents

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

2014-04-22

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

Microfluidic devices and methods including porous polymer monoliths

DOEpatents

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

2015-12-01

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

Thermally driven microfluidic pumping via reversible shape memory polymers

NASA Astrophysics Data System (ADS)

Robertson, J. M.; Rodriguez, R. X.; Holmes, L. R., Jr.; Mather, P. T.; Wetzel, E. D.

2016-08-01

The need exists for autonomous microfluidic pumping systems that utilize environmental cues to transport fluid within a network of channels for such purposes as heat distribution, self-healing, or optical reconfiguration. Here, we report on reversible thermally driven microfluidic pumping enabled by two-way shape memory polymers. After developing a suitable shape memory polymer (SMP) through variation in the crosslink density, thin and flexible microfluidic devices were constructed by lamination of plastic films with channels defined by laser-cutting of double-sided adhesive film. SMP blisters integrated into the devices provide thermally driven pumping, while opposing elastic blisters are used to generate backpressure for reversible operation. Thermal cycling of the device was found to drive reversible fluid flow: upon heating to 60 °C, the SMP rapidly contracted to fill the surface channels with a transparent fluid, and upon cooling to 8 °C the flow reversed and the channel re-filled with black ink. Combined with a metallized backing layer, this device results in refection of incident light at high temperatures and absorption of light (at the portions covered with channels) at low temperatures. We discuss power-free, autonomous applications ranging from thermal regulation of structures to thermal indication via color change.

Microfluidic paper-based analytical devices for potential use in quantitative and direct detection of disease biomarkers in clinical analysis.

PubMed

Lim, Wei Yin; Goh, Boon Tong; Khor, Sook Mei

2017-08-15

Clinicians, working in the health-care diagnostic systems of developing countries, currently face the challenges of rising costs, increased number of patient visits, and limited resources. A significant trend is using low-cost substrates to develop microfluidic devices for diagnostic purposes. Various fabrication techniques, materials, and detection methods have been explored to develop these devices. Microfluidic paper-based analytical devices (μPADs) have gained attention for sensing multiplex analytes, confirming diagnostic test results, rapid sample analysis, and reducing the volume of samples and analytical reagents. μPADs, which can provide accurate and reliable direct measurement without sample pretreatment, can reduce patient medical burden and yield rapid test results, aiding physicians in choosing appropriate treatment. The objectives of this review are to provide an overview of the strategies used for developing paper-based sensors with enhanced analytical performances and to discuss the current challenges, limitations, advantages, disadvantages, and future prospects of paper-based microfluidic platforms in clinical diagnostics. μPADs, with validated and justified analytical performances, can potentially improve the quality of life by providing inexpensive, rapid, portable, biodegradable, and reliable diagnostics. Copyright © 2017 Elsevier B.V. All rights reserved.

Direct 3D-printing of cell-laden constructs in microfluidic architectures.

PubMed

Liu, Justin; Hwang, Henry H; Wang, Pengrui; Whang, Grace; Chen, Shaochen

2016-04-21

Microfluidic platforms have greatly benefited the biological and medical fields, however standard practices require a high cost of entry in terms of time and energy. The utilization of three-dimensional (3D) printing technologies has greatly enhanced the ability to iterate and build functional devices with unique functions. However, their inability to fabricate within microfluidic devices greatly increases the cost of producing several different devices to examine different scientific questions. In this work, a variable height micromixer (VHM) is fabricated using projection 3D-printing combined with soft lithography. Theoretical and flow experiments demonstrate that altering the local z-heights of VHM improved mixing at lower flow rates than simple geometries. Mixing of two fluids occurs as low as 320 μL min(-1) in VHM whereas the planar zigzag region requires a flow rate of 2.4 mL min(-1) before full mixing occurred. Following device printing, to further demonstrate the ability of this projection-based method, complex, user-defined cell-laden scaffolds are directly printed inside the VHM. The utilization of this unique ability to produce 3D tissue models within a microfluidic system could offer a unique platform for medical diagnostics and disease modeling.

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 arbitrary 3D structures, while some perfluoropolymers are extremely inert and antifouling. Chemists can use hydrogels as highly permeable structural material, which allows diffusion of molecules without bulk fluid flows. They are used to support 3D cell culture, to form diffusion gradient, and to serve as actuators. Researchers have recently introduced paper-based devices, which are extremely low-cost to prepare and easy to use, thereby promising in commercial point-of-care assays. In general, the evolution of chip materials reflects the two major trends of microfluidic technology: powerful microscale research platforms and low-cost portable analyses. For laboratory research, chemists choosing materials generally need to compromise the ease in prototyping and the performance of the device. However, in commercialization, the major concerns are the cost of production and the ease and reliability in use. There may be new growth in the combination of surface engineering, functional materials, and microfluidics, which is possibly accomplished by the utilization of composite materials or hybrids for advanced device functions. Also, significant expanding of commercial applications can be predicted.

Generation of monodisperse cell-sized microdroplets using a centrifuge-based axisymmetric co-flowing microfluidic device.

PubMed

Yamashita, Hitoyoshi; Morita, Masamune; Sugiura, Haruka; Fujiwara, Kei; Onoe, Hiroaki; Takinoue, Masahiro

2015-04-01

We report an easy-to-use generation method of biologically compatible monodisperse water-in-oil microdroplets using a glass-capillary-based microfluidic device in a tabletop mini-centrifuge. This device does not require complicated microfabrication; furthermore, only a small sample volume is required in experiments. Therefore, we believe that this method will assist biochemical and cell-biological experiments. Copyright © 2014 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Microwell Arrays for Studying Many Individual Cells

NASA Technical Reports Server (NTRS)

Folch, Albert; Kosar, Turgut Fettah

2009-01-01

"Laboratory-on-a-chip" devices that enable the simultaneous culturing and interrogation of many individual living cells have been invented. Each such device includes a silicon nitride-coated silicon chip containing an array of micromachined wells sized so that each well can contain one cell in contact or proximity with a patch clamp or other suitable single-cell-interrogating device. At the bottom of each well is a hole, typically 0.5 m wide, that connects the well with one of many channels in a microfluidic network formed in a layer of poly(dimethylsiloxane) on the underside of the chip. The microfluidic network makes it possible to address wells (and, thus, cells) individually to supply them with selected biochemicals. The microfluidic channels also provide electrical contact to the bottoms of the wells.

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

Photopatterned materials in bioanalytical microfluidic technology

PubMed Central

Tentori, Augusto M.; Herr, Amy E.

2011-01-01

Microfluidic technologies are playing an increasingly important role in biological inquiry. Sophisticated approaches to the microanalysis of biological specimens rely, in part, on the fine fluid and material control offered by microtechnology, as well as a sufficient capacity for systems integration. A suite of techniques that utilize photopatterning of polymers on fluidic surfaces, within fluidic volumes, and as primary device structures underpins recent technological innovation in bioanalysis. Well-characterized photopatterning approaches enable previously fabricated or commercially fabricated devices to be customized by the user in a straight-forward manner, making the tools accessible to laboratories that do not focus on microfabrication technology innovation. In this review of recent advances, we summarize reported microfluidic devices with photopatterned structures and regions as platforms for a diverse set of biological measurements and assays. PMID:21857772

Real-time detection of neurite outgrowth using microfluidic device

NASA Astrophysics Data System (ADS)

Kim, Samhwan; Jang, Jongmoon; Choi, Hongsoo; Moon, Cheil

2013-05-01

We developed a simple method for real-time detection of the neurite outgrowth using microfluidic device. Our microfluidic device contains three compartmentalized channels which are for cell seeding, hydrogel and growth factors. Collagen gel is filled in the middle channel and pheochromocytoma (PC12) cells are seeded in the left channel. To induce differentiation of PC12 cells, 50 ng/ml to1000 ng/ml of nerve growth factor (NGF) is introduced into the right channel. After three days of NGF treatment, PC12 cells begin to extend neurites and formed neurite network from sixth day. Quantification of neurite outgrowth is analyzed by measuring the total area of neurites. On sixth day, the area is doubled compared to the area on third day and increases by 20 times on ninth day.

3D Printed Multimaterial Microfluidic Valve.

PubMed

Keating, Steven J; Gariboldi, Maria Isabella; Patrick, William G; Sharma, Sunanda; Kong, David S; Oxman, Neri

2016-01-01

We present a novel 3D printed multimaterial microfluidic proportional valve. The microfluidic valve is a fundamental primitive that enables the development of programmable, automated devices for controlling fluids in a precise manner. We discuss valve characterization results, as well as exploratory design variations in channel width, membrane thickness, and membrane stiffness. Compared to previous single material 3D printed valves that are stiff, these printed valves constrain fluidic deformation spatially, through combinations of stiff and flexible materials, to enable intricate geometries in an actuated, functionally graded device. Research presented marks a shift towards 3D printing multi-property programmable fluidic devices in a single step, in which integrated multimaterial valves can be used to control complex fluidic reactions for a variety of applications, including DNA assembly and analysis, continuous sampling and sensing, and soft robotics.

The pumping lid: investigating multi-material 3D printing for equipment-free, programmable generation of positive and negative pressures for microfluidic applications.

PubMed

Begolo, Stefano; Zhukov, Dmitriy V; Selck, David A; Li, Liang; Ismagilov, Rustem F

2014-12-21

Equipment-free pumping is a challenging problem and an active area of research in microfluidics, with applications for both laboratory and limited-resource settings. This paper describes the pumping lid method, a strategy to achieve equipment-free pumping by controlled generation of pressure. Pressure was generated using portable, lightweight, and disposable parts that can be integrated with existing microfluidic devices to simplify workflow and eliminate the need for pumping equipment. The development of this method was enabled by multi-material 3D printing, which allows fast prototyping, including composite parts that combine materials with different mechanical properties (e.g. both rigid and elastic materials in the same part). The first type of pumping lid we describe was used to produce predictable positive or negative pressures via controlled compression or expansion of gases. A model was developed to describe the pressures and flow rates generated with this approach and it was validated experimentally. Pressures were pre-programmed by the geometry of the parts and could be tuned further even while the experiment was in progress. Using multiple lids or a composite lid with different inlets enabled several solutions to be pumped independently in a single device. The second type of pumping lid, which relied on vapor-liquid equilibrium to generate pressure, was designed, modeled, and experimentally characterized. The pumping lid method was validated by controlling flow in different types of microfluidic applications, including the production of droplets, control of laminar flow profiles, and loading of SlipChip devices. We believe that applying the pumping lid methodology to existing microfluidic devices will enhance their use as portable diagnostic tools in limited resource settings as well as accelerate adoption of microfluidics in laboratories.

Characterization of three-dimensional cancer cell migration in mixed collagen-Matrigel scaffolds using microfluidics and image analysis

PubMed Central

Maška, Martin; Ederra, Cristina; Peláez, Rafael; Morales, Xabier; Muñoz-Arrieta, Gorka; Mujika, Maite; Kozubek, Michal; Muñoz-Barrutia, Arrate; Rouzaut, Ana; Arana, Sergio; Garcia-Aznar, José Manuel; Ortiz-de-Solorzano, Carlos

2017-01-01

Microfluidic devices are becoming mainstream tools to recapitulate in vitro the behavior of cells and tissues. In this study, we use microfluidic devices filled with hydrogels of mixed collagen-Matrigel composition to study the migration of lung cancer cells under different cancer invasion microenvironments. We present the design of the microfluidic device, characterize the hydrogels morphologically and mechanically and use quantitative image analysis to measure the migration of H1299 lung adenocarcinoma cancer cells in different experimental conditions. Our results show the plasticity of lung cancer cell migration, which turns from mesenchymal in collagen only matrices, to lobopodial in collagen-Matrigel matrices that approximate the interface between a disrupted basement membrane and the underlying connective tissue. Our quantification of migration speed confirms a biphasic role of Matrigel. At low concentration, Matrigel facilitates migration, most probably by providing a supportive and growth factor retaining environment. At high concentration, Matrigel slows down migration, possibly due excessive attachment. Finally, we show that antibody-based integrin blockade promotes a change in migration phenotype from mesenchymal or lobopodial to amoeboid and analyze the effect of this change in migration dynamics, in regards to the structure of the matrix. In summary, we describe and characterize a robust microfluidic platform and a set of software tools that can be used to study lung cancer cell migration under different microenvironments and experimental conditions. This platform could be used in future studies, thus benefitting from the advantages introduced by microfluidic devices: precise control of the environment, excellent optical properties, parallelization for high throughput studies and efficient use of therapeutic drugs. PMID:28166248

Adhesion and formation of microbial biofilms in complex microfluidic devices

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kumar, Aloke; Karig, David K; Neethirajan, Suresh

2012-01-01

Shewanella oneidensis is a metal reducing bacterium, which is of interest for bioremediation and clean energy applications. S. oneidensis biofilms play a critical role in several situations such as in microbial energy harvesting devices. Here, we use a microfluidic device to quantify the effects of hydrodynamics on the biofilm morphology of S. oneidensis. For different rates of fluid flow through a complex microfluidic device, we studied the spatiotemporal dynamics of biofilms, and we quantified several morphological features such as spatial distribution, cluster formation and surface coverage. We found that hydrodynamics resulted in significant differences in biofilm dynamics. The baffles inmore » the device created regions of low and high flow in the same device. At higher flow rates, a nonuniform biofilm develops, due to unequal advection in different regions of the microchannel. However, at lower flow rates, a more uniform biofilm evolved. This depicts competition between adhesion events, growth and fluid advection. Atomic force microscopy (AFM) revealed that higher production of extra-cellular polymeric substances (EPS) occurred at higher flow velocities.« less

Creating compact and microscale features in paper-based devices by laser cutting.

PubMed

Mahmud, Md Almostasim; Blondeel, Eric J M; Kaddoura, Moufeed; MacDonald, Brendan D

2016-11-14

In this work we describe a fabrication method to create compact and microscale features in paper-based microfluidic devices using a CO 2 laser cutting/engraving machine. Using this method we are able to produce the smallest features with the narrowest barriers yet reported for paper-based microfluidic devices. The method uses foil backed paper as the base material and yields inexpensive paper-based devices capable of using small fluid sample volumes and thus small reagent volumes, which is also suitable for mass production. The laser parameters (power and laser head speed) were adjusted to minimize the width of hydrophobic barriers and we were able to create barriers with a width of 39 ± 15 μm that were capable of preventing cross-barrier bleeding. We generated channels with a width of 128 ± 30 μm, which we found to be the physical limit for small features in the chromatography paper we used. We demonstrate how miniaturizing of paper-based microfluidic devices enables eight tests on a single bioassay device using only 2 μL of sample fluid volume.

Enhancing the biocompatibility of microfluidics-assisted fabrication of cell-laden microgels with channel geometry.

PubMed

Kim, Suntae; Oh, Jonghyun; Cha, Chaenyung

2016-11-01

Microfluidic flow-focusing devices (FFD) are widely used to generate monodisperse droplets and microgels with controllable size, shape and composition for various biomedical applications. However, highly inconsistent and often low viability of cells encapsulated within the microgels prepared via microfluidic FFD has been a major concern, and yet this aspect has not been systematically explored. In this study, we demonstrate that the biocompatibility of microfluidic FFD to fabricate cell-laden microgels can be significantly enhanced by controlling the channel geometry. When a single emulsion ("single") microfluidic FFD is used to fabricate cell-laden microgels, there is a significant decrease and batch-to-batch variability in the cell viability, regardless of their size and composition. It is determined that during droplet generation, some of the cells are exposed to the oil phase which is shown to have a cytotoxic effect. Therefore, a microfluidic device with a sequential ('double') flow-focusing channels is employed instead, in which a secondary aqueous phase containing cells enters the primary aqueous phase, so the cells' exposure to the oil phase is minimized by directing them to the center of droplets. This microfluidic channel geometry significantly enhances the biocompatibility of cell-laden microgels, while maintaining the benefits of a typical microfluidic process. This study therefore provides a simple and yet highly effective strategy to improve the biocompatibility of microfluidic fabrication of cell-laden microgels. Copyright © 2016 Elsevier B.V. All rights reserved.

A critical insight into the development pipeline of microfluidic immunoassay devices for the sensitive quantitation of protein biomarkers at the point of care.

PubMed

Barbosa, Ana I; Reis, Nuno M

2017-03-13

The latest clinical procedures for the timely and cost-effective diagnosis of chronic and acute clinical conditions, such as cardiovascular diseases, cancer, chronic respiratory diseases, diabetes or sepsis (i.e. the biggest causes of death worldwide), involve the quantitation of specific protein biomarkers released into the blood stream or other physiological fluids (e.g. urine or saliva). The clinical thresholds are usually in the femtomolar to picolomar range, and consequently the measurement of these protein biomarkers heavily relies on highly sophisticated, bulky and automated equipment in centralised pathology laboratories. The first microfluidic devices capable of measuring protein biomarkers in miniaturised immunoassays were presented nearly two decades ago and promised to revolutionise point-of-care (POC) testing by offering unmatched sensitivity and automation in a compact POC format; however, the development and adoption of microfluidic protein biomarker tests has fallen behind expectations. This review presents a detailed critical overview into the pipeline of microfluidic devices developed in the period 2005-2016 capable of measuring protein biomarkers from the pM to fM range in formats compatible with POC testing, with a particular focus on the use of affordable microfluidic materials and compact low-cost signal interrogation. The integration of these two important features (essential unique selling points for the successful microfluidic diagnostic products) has been missed in previous review articles and explain the poor adoption of microfluidic technologies in this field. Most current miniaturised devices compromise either on the affordability, compactness and/or performance of the test, making current tests unsuitable for the POC measurement of protein biomarkers. Seven core technical areas, including (i) the selected strategy for antibody immobilisation, (ii) the surface area and surface-area-to-volume ratio, (iii) surface passivation, (iv) the biological matrix interference, (v) fluid control, (vi) the signal detection modes and (vii) the affordability of the manufacturing process and detection system, were identified as the key to the effective development of a sensitive and affordable microfluidic protein biomarker POC test.

Slopes To Prevent Trapping of Bubbles in Microfluidic Channels

NASA Technical Reports Server (NTRS)

Greer, Harold E.; Lee, Michael C.; Smith, J. Anthony; Willis, Peter A.

2010-01-01

The idea of designing a microfluidic channel to slope upward along the direction of flow of the liquid in the channel has been conceived to help prevent trapping of gas bubbles in the channel. In the original application that gave rise to this idea, the microfluidic channels are parts of micro-capillary electrophoresis (microCE) devices undergoing development for use on Mars in detecting compounds indicative of life. It is necessary to prevent trapping of gas bubbles in these devices because uninterrupted liquid pathways are essential for sustaining the electrical conduction and flows that are essential for CE. The idea is also applicable to microfluidic devices that may be developed for similar terrestrial microCE biotechnological applications or other terrestrial applications in which trapping of bubbles in microfluidic channels cannot be tolerated. A typical microCE device in the original application includes, among other things, multiple layers of borosilicate float glass wafers. Microfluidic channels are formed in the wafers, typically by use of wet chemical etching. The figure presents a simplified cross section of part of such a device in which the CE channel is formed in the lowermost wafer (denoted the channel wafer) and, according to the present innovation, slopes upward into a via hole in another wafer (denoted the manifold wafer) lying immediately above the channel wafer. Another feature of the present innovation is that the via hole in the manifold wafer is made to taper to a wider opening at the top to further reduce the tendency to trap bubbles. At the time of reporting the information for this article, an effort to identify an optimum technique for forming the slope and the taper was in progress. Of the techniques considered thus far, the one considered to be most promising is precision milling by use of femtosecond laser pulses. Other similar techniques that may work equally well are precision milling using a focused ion beam, or a small diamond-tipped drill bit.

High-performance single cell genetic analysis using microfluidic emulsion generator arrays.

PubMed

Zeng, Yong; Novak, Richard; Shuga, Joe; Smith, Martyn T; Mathies, Richard A

2010-04-15

High-throughput genetic and phenotypic analysis at the single cell level is critical to advance our understanding of the molecular mechanisms underlying cellular function and dysfunction. Here we describe a high-performance single cell genetic analysis (SCGA) technique that combines high-throughput microfluidic emulsion generation with single cell multiplex polymerase chain reaction (PCR). Microfabricated emulsion generator array (MEGA) devices containing 4, 32, and 96 channels are developed to confer a flexible capability of generating up to 3.4 x 10(6) nanoliter-volume droplets per hour. Hybrid glass-polydimethylsiloxane diaphragm micropumps integrated into the MEGA chips afford uniform droplet formation, controlled generation frequency, and effective transportation and encapsulation of primer functionalized microbeads and cells. A multiplex single cell PCR method is developed to detect and quantify both wild type and mutant/pathogenic cells. In this method, microbeads functionalized with multiple forward primers targeting specific genes from different cell types are used for solid-phase PCR in droplets. Following PCR, the droplets are lysed and the beads are pooled and rapidly analyzed by multicolor flow cytometry. Using Escherichia coli bacterial cells as a model, we show that this technique enables digital detection of pathogenic E. coli O157 cells in a high background of normal K12 cells, with a detection limit on the order of 1/10(5). This result demonstrates that multiplex SCGA is a promising tool for high-throughput quantitative digital analysis of genetic variation in complex populations.

High-Performance Single Cell Genetic Analysis Using Microfluidic Emulsion Generator Arrays

PubMed Central

Zeng, Yong; Novak, Richard; Shuga, Joe; Smith, Martyn T.; Mathies, Richard A.

2010-01-01

High-throughput genetic and phenotypic analysis at the single cell level is critical to advance our understanding of the molecular mechanisms underlying cellular function and dysfunction. Here we describe a high-performance single cell genetic analysis (SCGA) technique that combines high-throughput microfluidic emulsion generation with single cell multiplex PCR. Microfabricated emulsion generator array (MEGA) devices containing 4, 32 and 96 channels are developed to confer a flexible capability of generating up to 3.4 × 106 nanoliter-volume droplets per hour. Hybrid glass-polydimethylsiloxane diaphragm micropumps integrated into the MEGA chips afford uniform droplet formation, controlled generation frequency, and effective transportation and encapsulation of primer functionalized microbeads and cells. A multiplex single cell PCR method is developed to detect and quantify both wild type and mutant/pathogenic cells. In this method, microbeads functionalized with multiple forward primers targeting specific genes from different cell types are used for solid-phase PCR in droplets. Following PCR, the droplets are lysed, the beads are pooled and rapidly analyzed by multi-color flow cytometry. Using E. coli bacterial cells as a model, we show that this technique enables digital detection of pathogenic E. coli O157 cells in a high background of normal K12 cells, with a detection limit on the order of 1:105. This result demonstrates that multiplex SCGA is a promising tool for high-throughput quantitative digital analysis of genetic variation in complex populations. PMID:20192178

Apparent Softening of Wet Graphene Membranes on a Microfluidic Platform.

PubMed

Ferrari, Gustavo A; de Oliveira, Alan B; Silvestre, Ive; Matos, Matheus J S; Batista, Ronaldo J C; Fernandes, Thales F D; Meireles, Leonel M; Eliel, Gomes S N; Chacham, Helio; Neves, Bernardo R A; Lacerda, Rodrigo G

2018-05-22

Graphene is regarded as the toughest two-dimensional material (highest in-plane elastic properties) and, as a consequence, it has been employed/proposed as an ultrathin membrane in a myriad of microfluidic devices. Yet, an experimental investigation of eventual variations on the apparent elastic properties of a suspended graphene membrane in contact with air or water is still missing. In this work, the mechanical response of suspended monolayer graphene membranes on a microfluidic platform is investigated via scanning probe microscopy experiments. A high elastic modulus is measured for the membrane when the platform is filled with air, as expected. However, a significant apparent softening of graphene is observed when water fills the microfluidic system. Through molecular dynamics simulations and a phenomenological model, we associate such softening to a water-induced uncrumpling process of the suspended graphene membrane. This result may bring substantial modifications on the design and operation of microfluidic devices which exploit pressure application on graphene membranes.

Femtosecond Laser Fabrication of Monolithically Integrated Microfluidic Sensors in Glass

PubMed Central

He, Fei; Liao, Yang; Lin, Jintian; Song, Jiangxin; Qiao, Lingling; Cheng, Ya; Sugioka, Koji

2014-01-01

Femtosecond lasers have revolutionized the processing of materials, since their ultrashort pulse width and extremely high peak intensity allows high-quality micro- and nanofabrication of three-dimensional (3D) structures. This unique capability opens up a new route for fabrication of microfluidic sensors for biochemical applications. The present paper presents a comprehensive review of recent advancements in femtosecond laser processing of glass for a variety of microfluidic sensor applications. These include 3D integration of micro-/nanofluidic, optofluidic, electrofluidic, surface-enhanced Raman-scattering devices, in addition to fabrication of devices for microfluidic bioassays and lab-on-fiber sensors. This paper describes the unique characteristics of femtosecond laser processing and the basic concepts involved in femtosecond laser direct writing. Advanced spatiotemporal beam shaping methods are also discussed. Typical examples of microfluidic sensors fabricated using femtosecond lasers are then highlighted, and their applications in chemical and biological sensing are described. Finally, a summary of the technology is given and the outlook for further developments in this field is considered. PMID:25330047

Precise pooling and dispensing of microfluidic droplets towards micro- to macro-world interfacing

PubMed Central

Brouzes, Eric; Carniol, April; Bakowski, Tomasz; Strey, Helmut H.

2014-01-01

Droplet microfluidics possesses unique properties such as the ability to carry out multiple independent reactions without dispersion of samples in microchannels. We seek to extend the use of droplet microfluidics to a new range of applications by enabling its integration into workflows based on traditional technologies, such as microtiter plates. Our strategy consists in developing a novel method to manipulate, pool and deliver a precise number of microfluidic droplets. To this aim, we present a basic module that combines droplet trapping with an on-chip valve. We quantitatively analyzed the trapping efficiency of the basic module in order to optimize its design. We also demonstrate the integration of the basic module into a multiplex device that can deliver 8 droplets at every cycle. This device will have a great impact in low throughput droplet applications that necessitate interfacing with macroscale technologies. The micro- to macro- interface is particularly critical in microfluidic applications that aim at sample preparation and has not been rigorously addressed in this context. PMID:25485102

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

PubMed Central

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

2009-01-01

A novel approach to integrating biochip and microfluidic devices is reported in which microcontact printing is a key fabrication technique. The process is performed using an automated microcontact printer that has been developed as an application-specific tool. As proof-of-concept the instrument is used to consecutively and selectively graft patterns of antibodies at the bottom of a glass channel for use in microfluidic immunoassays. Importantly, feature collapse due to over compression of the PDMS stamp is avoided by fine control of the stamp’s compression during contact. The precise alignment of biomolecules at the intersection of microfluidic channel and integrated optical waveguides has been achieved, with antigen detection performed via fluorescence excitation. Thus, it has been demonstrated that this technology permits sequential microcontact printing of isolated features consisting of functional biomolecules at any position along a microfluidic channel and also that it is possible to precisely align these features with existing components. PMID:20161128

Tilted pillar array fabrication by the combination of proton beam writing and soft lithography for microfluidic cell capture: Part 1 Design and feasibility.

PubMed

Rajta, Istvan; Huszánk, Robert; Szabó, Atilla T T; Nagy, Gyula U L; Szilasi, Szabolcs; Fürjes, Peter; Holczer, Eszter; Fekete, Zoltan; Járvás, Gabor; Szigeti, Marton; Hajba, Laszlo; Bodnár, Judit; Guttman, Andras

2016-02-01

Design, fabrication, integration, and feasibility test results of a novel microfluidic cell capture device is presented, exploiting the advantages of proton beam writing to make lithographic irradiations under multiple target tilting angles and UV lithography to easily reproduce large area structures. A cell capture device is demonstrated with a unique doubly tilted micropillar array design for cell manipulation in microfluidic applications. Tilting the pillars increased their functional surface, therefore, enhanced fluidic interaction when special bioaffinity coating was used, and improved fluid dynamic behavior regarding cell culture injection. The proposed microstructures were capable to support adequate distribution of body fluids, such as blood, spinal fluid, etc., between the inlet and outlet of the microfluidic sample reservoirs, offering advanced cell capture capability on the functionalized surfaces. The hydrodynamic characteristics of the microfluidic systems were tested with yeast cells (similar size as red blood cells) for efficient capture. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Towards non- and minimally instrumented, microfluidics-based diagnostic devices†

PubMed Central

Weigl, Bernhard; Domingo, Gonzalo; LaBarre, Paul; Gerlach, Jay

2009-01-01

In many health care settings, it is uneconomical, impractical, or unaffordable to maintain and access a fully equipped diagnostics laboratory. Examples include home health care, developing-country health care, and emergency situations in which first responders are dealing with pandemics or biowarfare agent release. In those settings, fully disposable diagnostic devices that require no instrument support, reagent, or significant training are well suited. Although the only such technology to have found widespread adoption so far is the immunochromatographic rapid assay strip test, microfluidics holds promise to expand the range of assay technologies that can be performed in formats similar to that of a strip test. In this paper, we review progress toward development of disposable, low-cost, easy-to-use microfluidics-based diagnostics that require no instrument at all. We also present examples of microfluidic functional elements—including mixers, separators, and detectors—as well as complete microfluidic devices that function entirely without any moving parts and external power sources. PMID:19023463

Microfluidic device having an immobilized pH gradient and PAGE gels for protein separation and analysis

DOEpatents

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

2012-12-11

Disclosed is a novel microfluidic device enabling on-chip implementation of a two-dimensional separation methodology. Previously disclosed microscale immobilized pH gradients (IPG) are combined with perpendicular polyacrylamide gel electrophoresis (PAGE) microchannels to achieve orthogonal separations of biological samples. Device modifications enable inclusion of sodium dodecyl sulfate (SDS) in the second dimension. The device can be fabricated to use either continuous IPG gels, or the microscale isoelectric fractionation membranes we have also previously disclosed, for the first dimension. The invention represents the first all-gel two-dimensional separation microdevice, with significantly higher resolution power over existing devices.

Microfluidic device having an immobilized pH gradient and page gels for protein separation and analysis

DOEpatents

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

2014-05-20

Disclosed is a novel microfluidic device enabling on-chip implementation of a two-dimensional separation methodology. Previously disclosed microscale immobilized pH gradients (IPG) are combined with perpendicular polyacrylamide gel electrophoresis (PAGE) microchannels to achieve orthogonal separations of biological samples. Device modifications enable inclusion of sodium dodecyl sulfate (SDS) in the second dimension. The device can be fabricated to use either continuous IPG gels, or the microscale isoelectric fractionation membranes we have also previously disclosed, for the first dimension. The invention represents the first all-gel two-dimensional separation microdevice, with significantly higher resolution power over existing devices.

Rapid determination of cell mass and density using digitally controlled electric field in a microfluidic chip.

PubMed

Zhao, Yuliang; Lai, Hok Sum Sam; Zhang, Guanglie; Lee, Gwo-Bin; Li, Wen Jung

2014-11-21

The density of a single cell is a fundamental property of cells. Cells in the same cycle phase have similar volume, but the differences in their mass and density could elucidate each cell's physiological state. Here we report a novel technique to rapidly measure the density and mass of a single cell using an optically induced electrokinetics (OEK) microfluidic platform. Presently, single cellular mass and density measurement devices require a complicated fabrication process and their output is not scalable, i.e., it is extremely difficult to measure the mass and density of a large quantity of cells rapidly. The technique reported here operates on a principle combining sedimentation theory, computer vision, and microparticle manipulation techniques in an OEK microfluidic platform. We will show in this paper that this technique enables the measurement of single-cell volume, density, and mass rapidly and accurately in a repeatable manner. The technique is also scalable - it allows simultaneous measurement of volume, density, and mass of multiple cells. Essentially, a simple time-controlled projected light pattern is used to illuminate the selected area on the OEK microfluidic chip that contains cells to lift the cells to a particular height above the chip's surface. Then, the cells are allowed to "free fall" to the chip's surface, with competing buoyancy, gravitational, and fluidic drag forces acting on the cells. By using a computer vision algorithm to accurately track the motion of the cells and then relate the cells' motion trajectory to sedimentation theory, the volume, mass, and density of each cell can be rapidly determined. A theoretical model of micro-sized spheres settling towards an infinite plane in a microfluidic environment is first derived and validated experimentally using standard micropolystyrene beads to demonstrate the viability and accuracy of this new technique. Next, we show that the yeast cell volume, mass, and density could be rapidly determined using this technology, with results comparable to those using the existing method suspended microchannel resonator.

Electron beam fabrication of a microfluidic device for studying submicron-scale bacteria

PubMed Central

2013-01-01

Background Controlled restriction of cellular movement using microfluidics allows one to study individual cells to gain insight into aspects of their physiology and behaviour. For example, the use of micron-sized growth channels that confine individual Escherichia coli has yielded novel insights into cell growth and death. To extend this approach to other species of bacteria, many of whom have dimensions in the sub-micron range, or to a larger range of growth conditions, a readily-fabricated device containing sub-micron features is required. Results Here we detail the fabrication of a versatile device with growth channels whose widths range from 0.3 μm to 0.8 μm. The device is fabricated using electron beam lithography, which provides excellent control over the shape and size of different growth channels and facilitates the rapid-prototyping of new designs. Features are successfully transferred first into silicon, and subsequently into the polydimethylsiloxane that forms the basis of the working microfluidic device. We demonstrate that the growth of sub-micron scale bacteria such as Lactococcus lactis or Escherichia coli cultured in minimal medium can be followed in such a device over several generations. Conclusions We have presented a detailed protocol based on electron beam fabrication together with specific dry etching procedures for the fabrication of a microfluidic device suited to study submicron-sized bacteria. We have demonstrated that both Gram-positive and Gram-negative bacteria can be successfully loaded and imaged over a number of generations in this device. Similar devices could potentially be used to study other submicron-sized organisms under conditions in which the height and shape of the growth channels are crucial to the experimental design. PMID:23575419

Rapid identification and susceptibility testing of uropathogenic microbes via immunosorbent ATP-bioluminescence assay on a microfluidic simulator for antibiotic therapy.

PubMed

Dong, Tao; Zhao, Xinyan

2015-02-17

The incorporation of pathogen identification with antimicrobial susceptibility testing (AST) was implemented on a concept microfluidic simulator, which is well suited for personalizing antibiotic treatment of urinary tract infections (UTIs). The microfluidic device employs a fiberglass membrane sandwiched between two polypropylene components, with capture antibodies immobilized on the membrane. The chambers in the microfluidic device share the same geometric distribution as the wells in a standard 384-well microplate, resulting in compatibility with common microplate readers. Thirteen types of common uropathogenic microbes were selected as the analytes in this study. The microbes can be specifically captured by various capture antibodies and then quantified via an ATP bioluminescence assay (ATP-BLA) either directly or after a variety of follow-up tests, including urine culture, antibiotic treatment, and personalized antibiotic therapy simulation. Owing to the design of the microfluidic device, as well as the antibody specificity and the ATP-BLA sensitivity, the simulator was proven to be able to identify UTI pathogen species in artificial urine samples within 20 min and to reliably and simultaneously verify the antiseptic effects of eight antibiotic drugs within 3-6 h. The measurement range of the device spreads from 1 × 10(3) to 1 × 10(5) cells/mL in urine samples. We envision that the medical simulator might be broadly employed in UTI treatment and could serve as a model for the diagnosis and treatment of other diseases.