We present a microfluidic approach for the expression of protein arrays. The device consists of thousands of reaction chambers controlled by micro-mechanical valves. The microfluidic device is mated to a microarray-printed gene library. These genes are then transcribed and translated on-chip, resulting in a protein array ready for experimental use.
We present a novel and powerful integration of nanophotonics (QD-FRET) and microfluidics to investigate the formation of polyelectrolyte polyplexes, which is expected to provide better control and synthesis of uniform and customizable polyplexes for future nucleic acid-based therapeutics.
An automated microfluidic device was developed for circulating nucleated cell enrichment from peripheral blood via erythrocyte lysis that ensures isolation of high quality sample without cell loss.
The fabrication of microfluidic channels and their implementation in experiments for studying the chemotactic foraging behaviour of marine microbes within a patchy nutrient seascape and the swimming behaviour of bacteria within shear flow are described.
Increasing cDNA Yields from Single-cell Quantities of mRNA in Standard Laboratory Reverse Transcriptase Reactions using Acoustic Microstreaming
1Florey Neuroscience Institutes and Centre for Neuroscience, University of Melbourne, 2Fluid Dynamics Group, CSIRO Materials Science and Engineering, 3Swinburne University of Technology, Faculty of Engineering and Industrial Sciences
We describe a novel method for increasing cDNA yield from single-cell quantities of mRNA in otherwise standard laboratory reverse transcription reactions. The novelty resides in the use of a micromixer, which utilizes the phenomenon of acoustic microstreaming, to mix fluids at microliter scales more effectively than shaking, vortexing or trituration.
Combining monodisperse drop generation with inertial ordering of cells and particles, we describe a method to encapsulate a desired number of cells or particles in a single drop at kHz rates. We demonstrate efficiencies twice exceeding those of unordered encapsulation for single- and double-particle drops.
Time-lapse Fluorescence Imaging of Arabidopsis Root Growth with Rapid Manipulation of The Root Environment Using The RootChip
1Department of Plant Biology, Carnegie Institution for Science, 2Howard Hughes Medical Institute, 3Departments of Applied Physics and Bioengineering, Stanford University, 4Department of Microsystems Engineering (IMTEK) and Center for Biological Signaling Studies (BIOSS), University of Freiburg
This article provides a protocol for cultivation of Arabidopsis seedlings in the RootChip, a microfluidic imaging platform that combines automated control of growth conditions with microscopic root monitoring and FRET-based measurement of intracellular metabolite levels.
A method for the assembly of adhesive and soluble gradients in a microscopy chamber for live cell migration studies is described. The engineered environment combines antifouling surfaces and adhesive tracks with solution gradients and therefore allows one to determine the relative importance of guidance cues.
1Department of Chemistry, Imperial College London, 2Department of Biochemistry, Protein Chip Research Center, Chungbuk National University, 3Department of Chemistry and Applied Biosciences, Institute for Chemical and Bioengineering, ETH Zurich
Droplet-based microfluidic platforms are promising candidates for high throughput experimentation since they are able to generate picoliter, self-compartmentalized vessels inexpensively at kHz rates. Through integration with fast, sensitive and high resolution fluorescence spectroscopic methods, the large amounts of information generated within these systems can be efficiently extracted, harnessed and utilized.
Digital Microfluidics is a technique characterized by the manipulation of discrete droplets (~nL - mL) on an array of electrodes by the application of electrical fields. It is well-suited for carrying out rapid, sequential, miniaturized automated biochemical assays. Here, we report a platform capable of automating several proteomic processing steps.
Micro-particle image velocimetry (μPIV) is used to visualize paired images of micro particles seeded in blood flows which are cross-correlated to give an accurate velocity profile. Shear rate, maximum velocity, velocity profile shape, and flow rate, each of which has clinical applications, can be derived from these measurements.
1Department of Ophthalmology, Massachusetts Eye and Ear, 2JoVE Content Production
Back in 1905, in what is now the Czech Republic, Eduard Zirm performed the first corneal transplantation surgery (keratoplasty), which restored vision to a patient blinded by corneal injury. Today, eye banks all over the world prepare, store, and distribute donated corneas to hospitals so that thousands of sight-saving keratoplasties can be performed every year. In June 2012, JoVE has its eye on two research groups, one from Italy and the other from Michigan, who demonstrate two distinct methods for corneal graft preparation prior to transplantation.
1Biomedical Engineering Department, Cornell University, 2Neurosurgical Laboratory for Translational Stem Cell Research, Weill Cornell Brain Tumor Center, Weill Cornell Medical College of Cornell University, 3Cell Morphology Department, Instituto de Investigacion Principe Felipe, 4Department of Chemical and Biomolecular Engineering, Cornell University
We demonstrate that the over expression of epidermal growth factor receptors (EGFR) enhances the motility of neural stem cells(NSCs) using a novel agarose gel based microfluidic device. This technology can be readily adaptable to other mammalian cell systems where cell sources are scarce, such as human neural stem cells, and the turn around time is critical.
1Department of Mechanical Engineering, Texas A&M University, 2Department of Mechanical Engineering and Department of Nuclear Engineering, Texas A&M University, 3Department of Chemical Engineering, Texas A&M University
We describe a novel method to perform DNA replication via the polymerase chain reaction (PCR). Thermal convection is harnessed to continuously shuttle reagents between denaturing, annealing, and extension conditions by maintaining opposing surfaces of the reactor at constant temperature. This inherently simple design promises to make rapid PCR more accessible.
Fluorescent-core microcavity sensors employ a high-index quantum-dot coating in the channel of silica microcapillaries. Changes in the refractive index of fluids pumped into the capillary channel cause shifts in the microcavity fluorescence spectrum that can be used to analyze the channel medium.
High efficiency, Site-specific Transfection of Adherent Cells with siRNA Using Microelectrode Arrays (MEA)
The article details the protocol for site-specific transfection of scrambled sequence of siRNA in an adherent mammalian cell culture using a microelectrode array (MEA).
We developed and validated a small-footprint array of miniature chemostats built from readily available parts for low cost. Physiological and experimental evolution results were similar to larger volume chemostats. The ministat array provides a compact, inexpensive, and accessible platform for traditional chemostat experiments, functional genomics, and chemical screening applications.
1Department of Pediatrics, University of Texas Southwestern Medical Center, 2Channing Laboratory, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, 3Department of Pediatrics and Microbiology, University of Texas Southwestern Medical Center
A reliable method for the RNA isolation of Pseudomonas aeruginosa recovered from murine cecums is described. The RNA recovered is of sufficient quantity and quality for subsequent qPCR, transcription profiling, and RNA Seq experiments. This technique can be adapted for RNA isolation of other intestinal microbes.
We have developed a flow cytometer using laser induced ultrasound to detect circulating melanoma cells as an early indicator of metastatic disease.
In this video we present the microfluidic probe1 (MFP). We explain in detail how to assemble the MFP, mount it atop an inverted microscope, and align it relative to the substrate surface, and finally show how to use it to process a substrate surface immersed in a buffer solution.
We developed a novel multi-compartment neuron co-culture microsystem platform for in vitro CNS axon-glia interaction research. The platform is capable of conducting up to six independent experiments in parallel and was fabricated using a newly developed macro/micro hybrid fabrication method.
Manipulating fluids and suspended particles in the micro- and nano-scale is becoming more of a reality as enabling technologies, like AC electrokinetics, continue to develop. Here, we discuss the physics behind AC electrokinetics, how to fabricate these devices and how to interpret the experimental observations.
In this interview, Dr. Klapperich discusses the fabrication of thermoplastic microfluidic devices and their application for development of new diagnostics.
Here we demonstrate how to fabricate thermoplastic microfluidic chips using hot embossing and heat sealing. Then we demonstrate how to use in situ light directed surface grafting and polymerization through the sealed chip to form the composite solid phase columns.
1Department of Biomedical Engineering, University of California, Irvine (UCI), 2Stem Cell Research Center, University of California, Irvine (UCI), 3Institute for Brain Aging and Dementia, University of California, Irvine (UCI)
In this video we demonstrate how to use the neuron microfluidic device without plasma bonding.
1Bio-Acoustic-MEMS Laboratory in Medicine (BAMM), HST-Center for Bioengineering, Brigham and Women's, Harvard Medical School, 2Bio-Acoustic-MEMS Laboratory in Medicine (BAMM), HST-Center for Bioengineering, Brigham and Women's Hospital, 3Brigham and Women's Hospital, Harvard Medical School, 4Harvard-MIT Division of Health Sciences and Technology, Massachusetts Institute of Technology; Center for Biomedical Engineering, Department of Medicine, Brigham and Women's Hospital
We demonstrate fabrication of a simple microfluidic device that can be integrated with standard electrophysiology setups to expose microscale surfaces of a brain slice in a well controlled manner to different neurotransmitters.
In this article we describe how we obtain FRET traces from individual DNA molecules immobilized to a surface using an automated scanning confocal microscope.
A microfluidic islet perifusion device was developed for the assessment of dynamic insulin secretion of multiple islets and simultaneous fluorescence imaging of calcium influx and mitochondrial potential changes.
This protocol describes the development of a microfluidic device for investigating bacterial chemotaxis in stable concentration gradients of chemoeffectors.
Isotachophoresis (ITP) is a robust electrokinetic separation and preconcentration technique with applications ranging from toxin detection to sample preparation. We review the physical principles of ITP and the methodology of applying this technique to two specific example applications: separation and detection of small molecules and purification of nucleic acids from cell culture lysate.
In this article, we present a microfluidic-based method for particle confinement based on hydrodynamic flow. We demonstrate stable particle trapping at a fluid stagnation point using a feedback control mechanism, thereby enabling confinement and micromanipulation of arbitrary particles in an integrated microdevice.
Microglia are resident macrophages that provide the first line of defense and immune surveillance of the central nervous system. MicroRNAs are regulatory molecules that play an important role in many physiological processes including activation and differentiation of macrophages. In this article, we describe the method for measurement of microRNAs in microglia.
Fabrication of Micropatterned Hydrogels for Neural Culture Systems using Dynamic Mask Projection Photolithography
Simple techniques are described for the rapid production of microfabricated neural culture systems using a digital micromirror device for dynamic mask projection lithography on regular cell culture substrates. These culture systems may be more representative of natural biological architecture, and the techniques described could be adapted for numerous applications.
A versatile plasma lithography technique has been developed to generate stable surface patterns for guiding cellular attachment. This technique can be applied to create cell networks including those that mimic natural tissues and has been used for studying several, distinct cell types.
Microfluidic Co-culture of Epithelial Cells and Bacteria for Investigating Soluble Signal-mediated Interactions
This protocol describes a microfluidic co-culture model for simultaneous and localized culture of epithelial cells and bacteria. This model can be used for investigating the role of different soluble molecular signals on pathogenesis as well as screen the effectiveness of putative probiotic bacterial strains.
Evaluation of Cancer Stem Cell Migration Using Compartmentalizing Microfluidic Devices and Live Cell Imaging
1Department of Biomedical Engineering, University of Wisconsin-Madison, 2Materials Science Program, University of Wisconsin-Madison, 3Department of Neurological Surgery, University of Wisconsin-Madison, 4Carbone Comprehensive Cancer Center and Center for Stem Cell and Regenerative Medicine, University of Wisconsin-Madison
A compartmentalizing microfluidic device for investigating cancer stem cell migration is described. This novel platform creates a viable cellular microenvironment and enables microscopic visualization of live cell locomotion. Highly motile cancer cells are isolated to study molecular mechanisms of aggressive infiltration, potentially leading to more effective future therapies.
1Department of Pediatrics, Emory University School of Medicine, 2Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, 3Aflac Cancer Center and Blood Disorders Service of Children's Healthcare of Atlanta, 4Winship Cancer Institute of Emory University
A method to culture an endothelial cell monolayer throughout the entire inner 3D surface of a microfluidic device with microvascular-sized channels (<30 μm) is described. This in vitro microvasculature model enables the study of biophysical interactions between blood cells, endothelial cells, and soluble factors in hematologic diseases.
Synthesis of Phase-shift Nanoemulsions with Narrow Size Distributions for Acoustic Droplet Vaporization and Bubble-enhanced Ultrasound-mediated Ablation
Phase-shift nanoemulsions (PSNE) can be vaporized using high intensity focused ultrasound to enhance localized heating and improve thermal ablation in tumors. In this report, the preparation of stable PSNE with a narrow size distribution is described. Furthermore, the impact of vaporized PSNE on ultrasound-mediated ablation is demonstrated in tissue-mimicking phantoms.