Embodiments of the present invention provide improved microfluidic devices and related apparatus, systems, and methods. Methods are provided for reducing mixing times during use of microfluidic devices. Microfluidic devices and related methods of manufacturing are provided with increased manufacturing yield rates. Improved apparatus and related systems are provided for supplying controlled pressure to microfluidic devices. Methods and related microfluidic devices are provided for reducing dehydration of microfluidic devices during use. Microfluidic devices and related methods are provided with improved sample to reagent mixture ratio control. Microfluidic devices and systems are provided with improved resistance to compression fixture pressure induced failures. Methods and systems for conducting temperature controlled reactions using microfluidic devices are provided that reduce condensation levels within the microfluidic device. Methods and systems are provided for improved fluorescent imaging of
Microfluidic devices have a wide variety of biological applications. My Ph.D. dissertation focuses on three major projects. A) culturing a non-adherent immortal cell line within a microfluidic device under static and dynamic media flow conditions; B) designing and fabricating novel microfluidic devices for electrokinetic injecting analytes from a hydrodynamic fluid; and C) using this novel injection method to lyse single non-adherent cells by applying a high electric field across the cell at a microfluidic channel intersection. There are several potential advantages to the use of microfluidic devices for the analysis of single cells: First, cells can be handled with care and precision while being transported in the microfluidic channels. Second, cell culturing, handling, and analysis can be integrated together in a single, compact microfluidic device. Third, cell culturing and analysis in microfluidic devices uses only extremely small volumes of culturing media and analysis buffer. In this ...
The use of microfluidic systems for screening of aptamers and their biomedical applications are reviewed in this paper. Aptamers with different nucleic acid sequences have been extensively studied and the results demonstrated a strong binding affinity to target molecules such that they can be used as promising candidate biomarkers for diagnosis and therapeutics. Recently, the aptamer screening protocol has been conducted with microfluidic-based devices. Furthermore, aptamer affinity screening by a microfluidic-based method has demonstrated remarkable advantages over competing traditional methods. In this paper, we first reviewed microfluidic systems which demonstrated efficient and rapid screening of a specific aptamer. Then, the clinical applications of screened aptamers, also performed by microfluidic systems, are further reviewed. These automated microfluidic systems can provide advantages over their conventional counterparts including more compactness, faster analysis, less sample/reagent
The market study on Global Microfluidic Devices Market 2017 Research Report studies current as well as future aspects of the Microfluidic Devices Market primarily based upon factors on which the companies compete in the market, key trends and segmentation analysis. This report covers each side of the worldwide market, ranging from the fundamental market info and advancing more to varied important criteria, based on that, the Microfluidic Devices market is segmented. Microfluidic Devices industry research report analyzes, tracks, and presents the global market size of the major players in every region around the world. Furthermore, the report provides data of the leading market players in the Microfluidic Devices market.. This report studies Microfluidic Devices in Global market, especially in North America, China, Europe, Southeast Asia, Japan and India, with production, revenue, consumption, import and export in these regions, from 2012 to 2017, and forecast to 2022.. Request for FREE Sample ...
misc{8894052, abstract = {Microfluidic applications nowadays have become of great interest due to their broad compatibility especially in biological applications, and one of them being droplet-based cell encapsulation. Cell encapsulation in droplets is carried out by discretising an aqueous phase (i.e. cell suspension) and including them into a continuous oil phase. This methodology is a potential gateway to high throughput droplet-based cell fusion (e.g. for the production of hybridomas). The challenge here is to achieve a high efficiency of correctly paired cells in a droplet to overcome the random fusion pairing during bulk cell fusion. As such, droplet microfluidics can be used to co-encapsulate a single cell A and a single cell B cells in one droplet or encapsulate cells separately and merge droplets with desired cell number and type subsequently with other droplet manipulations. In this study, separate encapsulation studies of human B lymphocytes and mouse embryonic stem cells were ...
A system and method for integrating microfluidic components in a microfluidic system enables the microfluidic system to perform a selected microfluidic function. A capping module includes a microfluidic element for performing a microfluidic function. The capping module is stacked on a microfluidic substrate having microfluidic plumbing to incorporate the microfluidic function into the system. The microfluidic element may comprise a matrix having an affinity for selected molecules in a sample. The matrix binds, reacts with and/or retains the selected molecules without affecting other molecules in the sample.
A system and method for integrating microfluidic components in a microfluidic system enables the microfluidic system to perform a selected microfluidic function. A capping module includes a microfluidic element for performing a microfluidic function. The capping module is stacked on a microfluidic substrate having microfluidic plumbing to incorporate the microfluidic function into the system. The microfluidic element may comprise a matrix having an affinity for selected molecules in a sample. The matrix binds, reacts with and/or retains the selected molecules without affecting other molecules in the sample.
Optical coherence tomography (OCT) angiography (OCTA) has been actively studied as a noninvasive imaging technology to generate retinal blood vessel network maps for the diagnoses of retinal diseases. Given that the uses of OCT and OCTA have increased in the field of ophthalmology, it is necessary to develop retinal phantoms for clinical OCT for product development, performance evaluation, calibration, certification, medical device licensing, and production processes. We developed a retinal layer-mimicking phantom with microfluidic channels based on microfluidic fabrication technology using polydimethylsiloxane (PDMS) and titanium dioxide (TiO2) powder. We implemented superficial and deep retinal vessels using microfluidic channels. In addition, multilayered thin films were synthesized with multiple spin-coating processes that comprised layers that corresponded to the retinal layers, including the ganglion cell layer (GCL), inner plexiform layer (IPL), and inner nuclear layer (INL). The phantom ...
Agave BioSystems proposes to develop and demonstrate an innovative Organic Thin Film Transistor (OTFT) to detect cell characteristics without the need for cell labeling for use in microfluidic flow cytometers. This sensor would be able to detect count all cells, whether the cells are fluorescently labeled or not. This device would easily be able to detect the presence of cells within the channel as well as give information about the cell size and even the DNA content or intactness of the cell. The fact that cells will not need to be fluorescently labeled for detection is one of the major advantages of this device, since it can be used to measure live, unperturbed cells. Microfabrication of the OTFTs and microfluidic components will allow development of inexpensive, self-contained, disposable, high-throughput devices for screening of combinatorial chemical, biochemical or biological libraries. Assisting in this project will be Prof. George Malliaras of the Department of Materials Science and ...
Microfluidic gradient generators are used to study the movement of living cells, lipid vesicles, and colloidal particles in response to spatial variations in their local chemical environment. Such gradient driven motions are often slow (less than 1 μm s−1) and therefore influenced or disrupted by fluid flows Lab on a Chip Emerging Investigators Lab on a Chip Recent HOT Articles
A variety of pulmonary diseases such as COPD, asthma, ARDS are profoundly associated with the surfactant dysfunction that leads to liquid plug formation across the airway lumen [19]. Several animal model studies have shown during such lung disorders severe tissue-level damage to the distal lung airways due to repeated closure and reopening process [4]. To mimic exactly the in vivo conditions, Huh et al. [20] developed a compartmentalized microfluidic airway models and demonstrated that the reopening of occluded microfluidic airway causes severe injury of pulmonary epithelial cells [20]. In the lung airways, rupturing of the liquid plugs leads to abnormal breath sounds known as crackles. To simulate this scenario, a three-dimensional (3D) microfluidic device was developed to detect acoustically the crackling sound and it was demonstrated that there is a higher risk of cell injury when liquid plugs become very thin. They demonstrated cellular level of lung injury under flow condition using this ...
The hanging drops are connected through 200μm-wide channels (Image: Chemistry World) Scientists in Switzerland have incorporated pulsing human heart tissue into a microfluidic device to make a miniscule model of a living system that could be used to test new drugs.. Microfluidic technology manipulates tiny volumes of liquid. One of its most exciting applications lies in building models of the human body - so-called body-on-a-chip or microphysiological systems. Many microphysiological systems already allow small human tissue samples, which approximate the behaviour of whole organs, to be tested under different conditions. Models of multi-organ systems are linked by slender liquid channels, and the flow of liquid and metabolites from one sample to the next can be controlled with pumps and valves. However, a huge challenge for the concept is that - after the attritive processes of extraction, culturing and insertion into a microfluidic environment - the samples often behave quite differently to ...
Developing blood-based tests is appealing for non-invasive disease diagnosis, especially when biopsy is difficult, costly, and sometimes not even an option. Tumor-derived exosomes have attracted increasing interest in non-invasive cancer diagnosis and monitoring of treatment response. However, the biology and clinical value of exosomes remains largely unknown due in part to current technical challenges in rapid isolation, molecular classification and comprehensive analysis of exosomes. Here we developed a new microfluidic approach to streamline and expedite the exosome analysis pipeline by integrating specific immunoisolation and targeted protein analysis of circulating exosomes. Compared to the conventional methods, our approach enables selective subpopulation isolation and quantitative detection of surface and intravesicular biomarkers directly from a minimally invasive amount of plasma samples (30 μL) within ~100 min with markedly improved detection sensitivity. Using this device, we ...
Microfluidic devices offer the chance to manipulate and analyze fluids including bioassays and chemical reactions. In this study, a method to develop a microfluidic analysis system is proposed for detection of nanotubes by a Raman acquisition setup. Microchannels where fabricated in sodalime glass substrate by MeV ion beam lithography or electron beam lithography and wet etching. Fusion bonding (550 °C) was used to seal the microchannels. As a result a prototype microfluidic device with 1.6 µm deep channel that exhibit efficient sealing and suitable channel geometry was obtained. The microfluidic device was tested in a Raman spectroscopy detection system and the collected spectra showed the presence of carbon nanotubes within the channel with clear RBM and G-band peaks. By this approach a practical and simple fabrication technique for microfluidic devices combined with Raman spectroscopy was done. This device can be enhanced to perform concentration maps within the channel and further research ...
Electrophoretic separation in nanofluidic channels exhibits significant differences with microfluidics. We discuss a theoretical / experimental collaboration investigating particle separation by electropohoresis in nanochannels. Recent experimental results in the laboratory of our collaborator Dr. Pennathur (UCSB, Dept. ME) indicate that increased fidelity can be achieved in separating particles by size and charge when using channels with cross sections of nanometer dimensions (100nm x 1000nm), as opposed to larger microfluidic channels. For short double-strands of DNA (10 - 100 base pairs) it is found that separation in microfluidic channels produces electropherograms with only one lumped peak. However, for nanofluidic channels several clearly distinct peaks are observed. Given the small dimensions of the nanofluidic channel, it is expected that new effects which were relatively weak in microfluidic channels play an important role. Identifying how these underlying mechanisms augment electrophoretic
A variable, closed-loop apparatus for regulating a microfluidic flow that employs a low-power deflection assembly, which is surface-mounted over a flexible membrane overlying a chamber integrated into a microfabricated platform. A flexible membrane, moveable between two positions, sealingly overlies the chamber. One of the positions of the membrane restricts the flow through the chamber to a greater degree than the other position. A deflection assembly disposed on the substrate over the membrane unidirectionally deflects the membrane, thereby regulating the flow through the chamber.
Culturing Pancreatic Islets in Microfluidic Flow Enhances Morphology of the Associated Endothelial Cells. . Biblioteca virtual para leer y descargar libros, documentos, trabajos y tesis universitarias en PDF. Material universiario, documentación y tareas realizadas por universitarios en nuestra biblioteca. Para descargar gratis y para leer online.
Circular dichroism (CD) is the differential absorption of left- and right-handed circularly polarized light. It is a form of spectroscopy used to determine the optical isomerism and secondary structure of molecules, and to study a wide variety of chiral materials in solution, particularly biologically important molecules such as proteins, nucleic acids, carbohydrates, lipids and drugs. The benefit of carrying out such experiments using synchrotron radiation is that the light available is several orders of magnitude higher in intensity than that available using conventional CD instruments, thereby providing a much higher signal-to-noise ratio over a wide wavelength range (140-700 nm). This paper will detail the development of a technique for rapidly producing 3D printed microfluidic channels in transparent polymer flow cells that enables the rapid and low-cost evaluation and iteration of microfluidic channel geometries. Permitting the flow through novel microfluidic devices to be interrogated thoroughly
TY - JOUR. T1 - Detection of culture-negative sepsis in clinical blood samples using a microfluidic assay for combined CD64 and CD69 cell capture. AU - Zhou, Yun. AU - Zhang, Ye. AU - Johnson, Amanda. AU - Venable, Amanda. AU - Griswold, John. AU - Pappas, Dimitri. PY - 2019/7/25. Y1 - 2019/7/25. N2 - Sepsis is a life-threatening disease that affects millions of people every year. Rapid detection of sepsis assists clinicians to initiate timely antibiotic therapy and to reduce mortality. At the same time, accurate point-of-care detection is needed to reduce unnecessary use of antibiotics. One of the principal challenges in sepsis diagnosis is that many sepsis cases do not result in positive blood cultures. These so-called culture-negative cases present a significant health threat. In this work, we present a microfluidic cells separation system for the detection of sepsis in both culture-positive and culture-negative cases. Leukocytes were captured in several affinity separation zones of a ...
The main aim of this project was to develop novel concepts for miniaturization of bioanalytical techniques for investigating biomolecular interactions. We used optical tweezers to selectively address individual biological objects in microfluidic channels. A general introduction of applications of optical tweezers and microfluidics is given in chapter 1. Theoretical concepts related to optical trapping and microfluidics are reviewed in chapter 2, followed by a detailed description of the instrumentation in chapter 3. In chapter 4, ligand-receptor interactions are studied under physiological conditions: whole cells or native vesicles carrying in their membrane the protein of interest are immobilized first in the laser trap inside a microfluidic channel, then the reaction is initiated by changing the solution in the region around the trap. In chapter 5 and chapter 6 respectively, surface-modified polystyrene beads are used to study ligand-receptor interactions and DNA hybridization. The examples of ...
The purpose of this thesis is to study the crystallization in a microfluidic device of an active pharmaceutical ingredient which is (2S)-2-[(4R)-2-oxo- 4-propylpyrrolidin-1-yl] butanamide, with product name Brivaracetam. This molecule is manufactured by the Belgian pharmaceutical industry UCB, and a better understanding of its crystallization in the microscopic scale, and especially its polymorphism, would lead to new possibilities in order to develop a future industrial continuous crystallizer based in the microfluidic technology. For this purpose, several experiments have been run, both in the macroscopic scale and using the microfluidics technology. The solubility curve for the system was determined, and also a cluster formation was analysed using volumes around 10ml of solution. Several crystallizations were done also with solutions of this volume to first understand the polymorphism that the solute presents. For the micro-scale crystallizations, the microfluidic device used was a system ...
TY - JOUR. T1 - Compartmentalized 3D Tissue Culture Arrays under Controlled Microfluidic Delivery. AU - Gümüscü, B.. AU - Albers, Hugo J.. AU - Van Den Berg, Albert. AU - Eijkel, Jan C.T.. AU - Van Der Meer, Andries D.. PY - 2017/12/1. Y1 - 2017/12/1. N2 - We demonstrate an in vitro microfluidic cell culture platform that consists of periodic 3D hydrogel compartments with controllable shapes. The microchip is composed of approximately 500 discontinuous collagen gel compartments locally patterned in between PDMS pillars, separated by microfluidic channels. The typical volume of each compartment is 7.5 nanoliters. The compartmentalized design of the microchip and continuous fluid delivery enable long-Term culturing of Caco-2 human intestine cells. We found that the cells started to spontaneously grow into 3D folds on day 3 of the culture. On day 8, Caco-2 cells were co-cultured for 36 hours under microfluidic perfusion with intestinal bacteria (E. coli) which did not overgrow in the system, and ...
TY - JOUR. T1 - DNA aptamer-based sandwich microfluidic assays for dual quantification and multi-glycan profiling of cancer biomarkers. AU - Jolly, Pawan. AU - Damborsky, P.. AU - Madaboosi, N.. AU - Soares, R.R.G.. AU - Chu, V.. AU - Conde, J.P.. AU - Katrlik, J.. AU - Estrela, Pedro. PY - 2016/5/16. Y1 - 2016/5/16. N2 - Two novel sandwich-based immunoassays for prostate cancer (PCa) diagnosis are reported, in which the primary antibody for capture is replaced by a DNA aptamer. The assays, which can be performed in parallel, were developed in a microfluidic device and tested for the detection of free Prostate Specific Antigen (fPSA). A secondary antibody (Aptamer-Antibody Assay) or a lectin (Aptamer-Lectin Assay) is used to quantify, by chemiluminescence, both the amount of fPSA and its glycosylation levels. The use of aptamers enables a more reliable, selective and controlled sensing of the analyte. The dual approach provides sensitive detection of fPSA along with selective fPSA ...
Accurate analysis at the single-cell level has become a highly attractive tool for investigating cellular content. An electroosmotic-driven microfluidic chip with arrays of 30-µm-diameter microwells was developed for single-cell electric lysis in the present study. The cellular occupancy in the microwells when the applied voltage was 5 V (82.4%) was slightly higher than that at an applied voltage of 10 V (81.8%). When the applied voltage was increased to 15 V, the cellular occupancy in the microwells dropped to 64.3%. More than 50% of the occupied microwells contain individual cells. The results of electric lysis experiments at the single-cell level indicate that the cells were gradually lysed as the DC voltage of 30 V was applied; the cell was fully lysed after 25 s. Single-cell electric lysis was demonstrated in the proposed microfluidic chip, which is suitable for high-throughput cell lysis.
Health, ...ANN ARBOR Mich. Cancer cells are on the move in the bloodstream in t...In a study of 51 patients researchers used a state-of-the art microfl...The findings published in Gastroenterology suggest that circu... While there is much work that still needs to be done there is great ...,Microfluidic,technology,reveals,potential,biomarker,for,early,pancreatic,cancer,medicine,medical news today,latest medical news,medical newsletters,current medical news,latest medicine news
A microsystem integrating electrochemical detection for the simultaneous detection of protein markers of breast cancer is reported. The microfluidic platform was realized by high precision milling of polycarbonate sheets and features two well distinguishable sections: a detection zone incorporating the elect
This paper reports on the electrochemical characterization and comparison of printable silver inks for the fabrication of planar electrodes to integrate in a microfluidic platform for in situ desalination of seawater prior to detection of nutrients in marine environment. Screen printing and inkjet printing were investigated to overcome limitations of more conventional deposition techniques. The screen printed ink DuPont 5064H was chosen for the fabrication of the desalination platform as it displayed the best properties in terms of oxidation ability (15.5 mC/mm(2)) and absence of sample contamination. The platform was tested at different oxidation conditions; the optimum potential for desalination was found to be +0.9 V. The device desalination performance was then evaluated through conductivity measurements of the treated sample and a proof-of-concept was achieved: for a potential of +0.9 V, conductivity (hence concentration) could be lowered from an initial value of 42.13 mS (0.6 M) to 20.36 ...
Video articles in JoVE about microfabrication include Microfabrication of Nanoporous Gold Patterns for Cell-material Interaction Studies, Microfabrication of Chip-sized Scaffolds for Three-dimensional Cell cultivation, Ordering Single Cells and Single Embryos in 3D Confinement: A New Device for High Content Screening, Experimental Methods for Trapping Ions Using Microfabricated Surface Ion Traps, Image-guided, Laser-based Fabrication of Vascular-derived Microfluidic Networks, A Microfluidic System with Surface Patterning for Investigating Cavitation Bubble(s)-Cell Interaction and the Resultant Bioeffects at the Single-cell Level, Creating Sub-50 Nm Nanofluidic Junctions in PDMS Microfluidic Chip via Self-Assembly Process of Colloidal Particles, Soft Lithographic Procedure for Producing Plastic Microfluidic Devices with View-ports Transparent to Visible and Infrared Light, A Microfluidic Platform for Precision Small-volume Sample Processing and Its Use to Size Separate Biological
Here a new approach to perform patch-clamp investigations under anoxic and normoxic conditions on nerve cells from Sprague Dawley rats is presented. A patch-clamp micropipette is integrated within a poly-methyl methacrylate (PMMA) based microchip giving optimal control over the oxygen content and the biochemical environment. Nerve cells were trapped by optical tweezers and steered towards the patch-clamp micropipette within the micro-channels. Several experiments were performed to show proof of principle. The oxygen content within the microfluidic chamber was measured to 0.5-1.5 %. The photo-induced effect of the optical tweezers on the nerve cells was investigated in an open Petri dish. The optical trapping did not influence measurements. The microfluidic system was further tested in patch-clamp experiments. This approach showed significant advantages regarding the tuning of the oxygen content and may be used in various electrophysiological investigations of single cells demanding optimal ...
Microfluidic devices can be used for many applications, including the formation of well-controlled emulsions. In this study, the capability to continuously create mono-disperse droplets in a microfluidic device is used to form calcium-alginate capsules through chemical crosslinking from aqueous droplets of calcium chloride and sodium alginate suspended in an oil solution. Calcium-alginate capsules have many potential uses, such as immunoisolation of cells, microencapsulation of active drug ingredients, and encapsulation of bitter agents in food or beverage products. Capsule formation is accomplished through fusion of a sodium alginate droplet and a calcium chloride droplet. The high surface tension between the droplet of calcium chloride and sodium alginate necessitates the use of the surfactant sodium dodecyl sulfate (SDS) and a device with a judiciously designed geometry. After creating the capsules, it is necessary to separate them out of the oil solution and into an aqueous solution. A ...
Microfluidic fluorescence assay devices show great promise as preclinical and clinical diagnostic instruments. Normally, fluorescence signals from microfluidic chips are quantified by analysis of images obtained with a commercial fluorescence microscope. This method is unnecessarily expensive, time consuming, and requires significant operator training, particularly when considering future clinical translation of the technology. In this work, we developed a dedicated low cost fluorescence microfluidic device reader (FMDR) to read sandwich immunofluorescence assay (sIFA) devices configured to detect vascular endothelial growth factor ligand concentrations in ocular fluid samples. Using a series of sIFA calibration standards and a limited set of human ocular fluid samples, we demonstrated that our FMDR reader has similar sensitivity and accuracy to a fluorescence microscope for this task, with significantly lower total cost and reduced reading time. We anticipate that the reader could be used with ...
In order to overcome these challenges, we aim to develop a novel breast cancer model that incorporates the relevant properties of the three-dimensional microenvironment. For this purpose, we use microfluidic technology, which enables us to manipulate and control fluids at the small scale. Cell encapsulation is used to first generate soft, cell-containing beads that mimic the basement membrane. These beads are then embedded in a more fibrous matrix that mimics the stromal ECM, completing the tissue model.
The ability to control the deposition and location of adherent and non-adherent cells within microfluidic devices is beneficial for the development of micro-scale bioanalytical tools and high-throughput screening systems. Here, we introduce a simple technique to fabricate poly(ethylene glycol) (PEG) microstructures within microfluidic channels that can be used to dock cells within pre-defined locations. Microstructures of various shapes were used to capture and shear-protect cells despite medium flow in the channel. Using this approach, PEG microwells were fabricated either with exposed or non-exposed substrates. Proteins and cells adhered within microwells with exposed substrates, while non-exposed substrates prevented protein and cell adhesion (although the cells were captured inside the features). Furthermore, immobilized cells remained viable and were stained for cell surface receptors by sequential flow of antibodies and secondary fluorescent probes. With its unique strengths in utility and ...
Microlytic was founded in 2006 with the intention to use microfluidic technology to help solve the major problems in structural biology. Microlytic sought to develop and produce microfluidic chips that offered a high probability of crystallizing target proteins with a set-up that is simple and easy to use.. Microlytic developed microfluidic chips to let users grow crystals large enough to be used immediately for X-ray diffraction, plus give users direct access to the crystals themselves. These goals were realized with the development of the Crystal Former - the first microfluidic platform to allow users to go from crystallization screen to structure using a single device.. The advantages of the Crystal Former are ...
Fabrication of conductive pathways, microcircuits and microstructures in microfluidic networks - Disclosed herein are a variety of microfluidic devices and solid, typically electrically conductive devices that can be formed using such devices as molds. In certain embodiments, the devices that are formed comprise conductive pathways formed by solidifying a liquid metal present in one or more microfluidic channels (such devices hereinafter referred to as "microsolidic" devices). In certain such devices, in which electrical connections can be formed and/or reformed between regions in a microfluidic structure; in some cases, the devices/circuits formed may be flexible and/or involve flexible electrical components. In certain embodiments, the solid metal wires/conductive pathways formed in microfluidic channel(s) may remain contained within the microfluidic structure. In certain such embodiments, the conductive pathways formed may be located in proximity to other microfluidic channel(s) of the ...
The invention provides a microfluidic device having a plurality of chambers each containing separately deposited reagents. The invention also provides an efficient PCR-based method for producing a linear expression template. The invention also provides methods for analyzing interactions between molecules, involving flow-deposition of expression templates on the substrate of chambers in a microfluidic device, and expressing proteins from the templates.
TY - JOUR. T1 - Ranking migration cue contributions to guiding individual fibroblasts faced with a directional decision in simple microfluidic bifurcations. AU - Pham, Quang Long. AU - Tong, Anh. AU - Rodrigues, Lydia N.. AU - Zhao, Yang. AU - Surblyte, Migle. AU - Ramos, Diomar. AU - Brito, John. AU - Rahematpura, Adwik. AU - Voronov, Roman S.. PY - 2019/5/1. Y1 - 2019/5/1. N2 - Directed cell migration in complex micro-environments, such as in vivo pores, is important for predicting locations of artificial tissue growth and optimizing scaffold architectures. Yet, the directional decisions of cells facing multiple physiochemical cues have not been characterized. Hence, we aim to provide a ranking of the relative importance of the following cues to the decision-making of individual fibroblast cells: chemoattractant concentration gradient, channel width, mitosis, and contact-guidance. In this study, bifurcated micro-channels with branches of different widths were created. Fibroblasts were then ...
A fluid interface port in a microfluidic system and a method of forming the fluid interface port is provided. The fluid interface port comprises an opening formed in the side wall of a microchannel sized and dimensioned to form a virtual wall when the microchannel is filled with a first liquid. The fluid interface port is utilized to fill the microchannel with a first liquid, to introduce a second liquid into the first liquid and to eject fluid from the microchannel.
0012]In one aspect, the present invention provides a method for controlling the temperature of a heater electrode associated with a microfluidic channel of a microfluidic device, wherein power applied to the heater electrode is regulated by varying the duty cycle of a pulse width modulation (PWM). In one embodiment, the method includes: (a) applying a fixed voltage across a circuit including the heater electrode, a switching element for selectively opening or closing the circuit to define the duty cycle, and a high resistance shunt around the switching element; (b) closing the circuit with the switching element for a period time corresponding to a power-on portion of a desired duty cycle and passing current to the heater electrode through the closed switch and the shunt; (c) while the circuit is closed, measuring a power-on voltage drop across the heater electrode; (d) computing a power-on resistance of the heater electrode based on the fixed voltage, the measured power-on voltage drop, and the ...
Engineering cellular microenvironments that more accurately reflect the in vivo situation is now recognized as being crucial for the improvement of the in vitro viability and in vivo-like function of cells or tissues. Microfluidic technologies have been increasingly applied since the late 1990s for this purpose, with a growing number of examples of perfused cell and tissue cultures in microfluidic chambers and channels. The well-defined solution flows provided by microfluidics mean enhanced cell growth and function through improved nutrient delivery and waste removal. Additional benefits include the implementation of well-defined temporal and spatial (bio)chemical gradients, and mechanical signals that cells experience in their natural environment. Because the ability to culture cells and tissue under such controlled conditions leads to cellular function that is distinctly more organ-like, the microfluidic systems used are now referred to as "organs-on-a-chip" or "microphysiological systems". ...
Porous monolithic polymers are a new category of materials developed during the last decade. In contrast to polymers composed of very small beads, a monolith is a single, continuous piece of a polymer prepared using a simple molding process. In this case, the microfluidic chips channel serves as the mold. And when this monolithic polymer fills the channels cross section, the dilute sample is exposed to much more active surface as it courses through the channel. This increases the opportunity for the chemical interactions that capture the desired compound from the sample. In early tests, for example, Svec and Fréchet increased the concentration of proteins extracted from a dilute solution by a factor of 1000. To prepare the polymer in the microfluidic chip, the channel is first filled with a liquid mixture of monomers and porogens. Next, a mask that is opaque to ultraviolet light is placed over the chip. This mask has a small slit that exposes a small portion of the channel. Finally, the ...
According to the Jan. 15, 2009, Genetic Engineering and Biotechnology News, the market for microfluidic technology will climb toward $1.9 billion over
A system and method for preventing or reducing unwanted heat in a microfluidic of the device while generating heat in selected regions of the device. In one example, current is supplied to a heating element through electric leads, wherein the leads are designed so that the current density in the leads is substantially lower than the current density in the heating element. This may be accomplished using conductive leads which have a cross-sectional area which is substantially greater than the cross-sectional area of the heating element. In another example, unwanted heat in the microfluidic complex is reduced by thermally isolating the electric leads from the microfluidic complex. This may be accomplished by running each lead directly away from the microfluidic complex, through a thermally isolating substrate. After the leads pass through the thermally isolating substrate, they are then routed to the current source. Thus, the thermally isolating substrate substantially blocks the transfer of heat from the
The way in which bacterial communities colonize flow in porous media is of importance but basic knowledge on the dynamic of these phenomena is still missing. The aim of this work is to develop microfluidic experiments in order to progress in the understanding of bacteria capture in filters and membranes. PDMS microfluidic devices mimicking filtration processes have been developed to allow a direct dynamic observation of bacteria across 10 or 20 micrometers width microchannels. When filtered in such devices, bacteria behave surprisingly: Escherichia coli, Pseudomonas aeruginosa or Staphylococcus aureus accumulate in the downstream zone of the filter and form large streamers which oscillate in the flow. In this study streamer formation is put in evidence for bacteria suspension in non nutritive conditions in less than one hour. This result is totally different from the one observed in same system with inert particles or dead bacteria which are captured in the bottleneck zone and are accumulated in the
Nicolas Szitas research interests focus on the translation of bioprocessing concepts into microfluidic systems (or Lab-on-a-chip systems). He has particular expertise in the use of advanced microfabrication techniques for polymers (rapid prototyping), glass and silicon. He co-ordinates the research activities of the Microfluidics Laboratory in Biochemical Engineering, and collaborates with the London Centre for Nanotechnology (LCN). Microfluidic devices provide an environment conducive to cell growth, operate with much smaller volumes, reducing the amount of cells and media required, and can be fitted with instrumentation for the real-time monitoring of assays. Additionally, they offer advantages unavailable at the larger scales, such as precise temporal and spatial control over the cellular microenvironment, and the scale-out to platforms of multiple microfluidic systems for high-throughput applications. Microfluidic systems are thus particularly suitable for the development of novel ...
Assessment of a tumors molecular makeup using biofluid samples, known as liquid biopsy, is a prominent research topic in precision medicine for cancer, due to its noninvasive property allowing repeat sampling for monitoring molecular changes of tumors over time. Circulating exosomes recently have been recognized as promising tumor surrogates because they deliver enriched biomarkers, such as proteins, RNAs, and DNA. However, purification and characterization of these exosomes are technically challenging. Microfluidic lab-on-a-chip technology effectively addresses these challenges owing to its inherent advantages in integration and automation of multiple functional modules, enhancing sensing performance, and expediting analysis processes. In this article, we review the state-of-the-art development of microfluidic technologies for exosome isolation and molecular characterization with emphasis on their applications toward liquid biopsy-based analysis of cancer. Finally, we share our perspectives on ...
The 18-well titer plate works with the spacing of a 96-well microtiter plate namely 9 mm and is available in different materials and in transparent and colored versions It can be used with our adapter frame in microtiter-plate format that is made as a special adapter for microfluidic chips in
Streets, A.M., Zhang, X., Cao, C. et al.. RNA sequencing of single cells enables measurement of biological variation in heterogeneous cellular populations and dissection of transcriptome complexity that is masked in ensemble measurements of gene expression. The low quantity of RNA in a single cell, however, hinders efficient and consistent reverse transcription and amplification of cDNA, limiting accuracy and obscuring biological variation with high technical noise. We developed a microfluidic approach to prepare cDNA from single cells for high-throughput transcriptome sequencing. The microfluidic platform facilitates single-cell manipulation, minimizes contamination, and furthermore, provides improved detection sensitivity and measurement precision, which is necessary for differentiating biological variability from technical noise. ...
A PED (precision extrusion deposition)/replica molding process enables scaffold guided tissue engineering of a heterocellular microfluidic device. We investigate two types of cell-laden devices: the first with a 3D microfluidic manifold fully embedded in a PDMS (polydimethylsiloxane) substrate and the second a channel network on the surface of the PDMS substrate for cell printing directly into device channels. Fully embedded networks are leak-resistant with simplified construction methods. Channels exposed to the surface are used as mold to hold bioprinted cell-laden matrix for controlled cell placement throughout the network from inlet to outlet. The result is a 3D cell-laden microfluidic device with improved leak-resistance (up to 2.0 mL/min), pervasive diffusion and control of internal architecture.. ...
This review describes the formation of microvortices in microfluidic systems, and discusses our experimental measurements that illustrate the velocity profiles inside such microvortices. Because of the micrometer dimensions of these vortices and the presence of high rotational velocities, we have observed a number of unique phenomena. One example is the dynamic formation of ring patterns of particles within the microvortex. The mechanism by which these patterns form relies on a balance between the centrifugal and displacement forces experienced by the re-circulating particles with a lift force exerted on the particles near the solid boundary of the microcavity. We also demonstrate the ability to orient and rotate precisely micro and nanometer -sized particles, individual DNA molecules, and single cells. Because of the high linear velocity (m/s) of fluid flow in constricted microchannels and to the small radii (, 10μm) of the microvortices, we have measured the presence of ultrahigh radial ...