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Journal of Laboratory Automation Dec 2013Elucidation of the heterogeneity of cells is a challenging task due to the lack of efficient analytical tools to make measurements with single-cell resolution.... (Review)
Review
Elucidation of the heterogeneity of cells is a challenging task due to the lack of efficient analytical tools to make measurements with single-cell resolution. Microfluidics has emerged as a powerful platform for single-cell analysis with the ability to manipulate small volume and integrate multiple sample preparation steps into one device. In this review, we discuss the differentiating advantages of microfluidic platforms that have been demonstrated for single-cell protein analysis.
Topics: Biomedical Research; Microfluidics; Proteins; Single-Cell Analysis
PubMed: 23821679
DOI: 10.1177/2211068213494389 -
Journal of the American Chemical Society Jul 2005This paper analyzes the effect of mixing on nucleation of protein crystals. The mixing of protein and precipitant was controlled by changing the flow rate in a...
This paper analyzes the effect of mixing on nucleation of protein crystals. The mixing of protein and precipitant was controlled by changing the flow rate in a plug-based microfluidic system. The nucleation rate inversely depended on the flow rate, and flow rate could be used to control nucleation. For example, at higher supersaturations, precipitation happened at low flow rates while large crystals grew at high flow rates. Mixing at low flow velocities in a winding channel induces nucleation more effectively than mixing in straight channels. A qualitative scaling argument that relies on a number of assumptions is presented to understand the experimental results. In addition to helping fundamental understanding, this result may be used to control nucleation, using rapid chaotic mixing to eliminate formation of precipitates at high supersaturation and using slow chaotic mixing to induce nucleation at lower supersaturation.
Topics: Crystallization; Microfluidics; Proteins
PubMed: 15998056
DOI: 10.1021/ja052279v -
Cytometry. Part a : the Journal of the... Jul 2010Microfabricated flow cytometers can detect, count, and analyze cells or particles using microfluidics and electronics to give impedance-based characterization. Such... (Review)
Review
Microfabricated flow cytometers can detect, count, and analyze cells or particles using microfluidics and electronics to give impedance-based characterization. Such systems are being developed to provide simple, low-cost, label-free, and portable solutions for cell analysis. Recent work using microfabricated systems has demonstrated the capability to analyze micro-organisms, erythrocytes, leukocytes, and animal and human cell lines. Multifrequency impedance measurements can give multiparametric, high-content data that can be used to distinguish cell types. New combinations of microfluidic sample handling design and microscale flow phenomena have been used to focus and position cells within the channel for improved sensitivity. Robust designs will enable focusing at high flowrates while reducing requirements for control over multiple sample and sheath flows. Although microfluidic impedance-based flow cytometers have not yet or may never reach the extremely high throughput of conventional flow cytometers, the advantages of portability, simplicity, and ability to analyze single cells in small populations are, nevertheless, where chip-based cytometry can make a large impact.
Topics: Animals; Cell Death; Cell Differentiation; Cell Physiological Phenomena; Cell Survival; Electric Impedance; Equipment Design; Flow Cytometry; Humans; Microfluidics; Sensitivity and Specificity
PubMed: 20583276
DOI: 10.1002/cyto.a.20910 -
ACS Sensors Nov 2022The laminar flow interface (LFI) developed at low Reynolds numbers is one of the most prominent features of microscale flows and has been employed in a diverse range of...
The laminar flow interface (LFI) developed at low Reynolds numbers is one of the most prominent features of microscale flows and has been employed in a diverse range of optofluidic applications. The formation of LFIs usually requires the manipulation of multiple streams within a microchannel using a complex hydrodynamic pumping system. Herein, we present a new type of LFI that is generated by fluid switching within a three-dimensional (3D) microlens-incorporating microfluidic chip (3D-MIMC). Since Poiseuille flows exhibit a parabolic velocity profile, the LFI is cone-like in shape and acts as a transient refractive interface (TRI), which is sensitive to the refractive index () and the Péclet number () of the switching fluids. In response to the TRI, the intensity of the transmitted light can be intensified or attenuated depending on the sequence of fluid switching operations. By incorporating three-dimensional (3D) microlenses and increasing the values, the profile and amplitude of the intensity peak are both significantly improved. The limit of detection (LoD) for a sodium chloride (NaCl) solution at = 1363 is as low as 0.001% (w/w), representing an improvement of 1-2 orders of magnitude when compared to existing optofluidic concentration sensors based on intensity modulation. Fluid switching of a variety of inorganic and organic sample fluids confirms that the specific optical response () correlates positively with both and the specific (), obeying a linear relationship. This model is further verified through cross-validations and used to estimate the molecular diffusion coefficient () of a range of species. Furthermore, by virtue of the TRI, we achieve a sensitive measurement of optical-equivalent total dissolved solids (OE-TDS) for environmental samples.
Topics: Microfluidics; Microfluidic Analytical Techniques; Refractometry; Hydrodynamics
PubMed: 36356161
DOI: 10.1021/acssensors.2c01901 -
Urologic Oncology Aug 2021Microfluidic systems aim to detect sample matter quickly with high sensitivity and resolution, on a small scale. With its increased use in medicine, the field is showing... (Review)
Review
Microfluidic systems aim to detect sample matter quickly with high sensitivity and resolution, on a small scale. With its increased use in medicine, the field is showing significant promise in prostate cancer diagnosis and management due, in part, to its ability to offer point-of-care testing. This review highlights some of the research that has been undertaken in respect of prostate cancer and microfluidics. Firstly, this review considers the diagnosis of prostate cancer through use of microfluidic systems and analyses the detection of prostate specific antigen, proteins, and circulating tumor cells to highlight the scope of current advancements. Secondly, this review analyses progressions in the understanding of prostate cancer physiology and considers techniques used to aid treatment of prostate cancer, such as the creation of a micro-environment. Finally, this review highlights potential future roles of microfluidics in assisting prostate cancer, such as in exosomal analysis. In conclusion, this review shows the vast scope and application of microfluidic systems and how these systems will ensure advancements to future prostate cancer management.
Topics: Humans; Lab-On-A-Chip Devices; Male; Microfluidics; Neoplastic Cells, Circulating; Prostatic Neoplasms; Tumor Microenvironment
PubMed: 33934962
DOI: 10.1016/j.urolonc.2021.03.010 -
ACS Sensors Jun 2024Health and security concerns have made it essential to develop integrated, continuous collection and sensing platforms that are compact and capable of real-time...
Health and security concerns have made it essential to develop integrated, continuous collection and sensing platforms that are compact and capable of real-time detection. In this study, we numerically investigate the flow physics associated with the single-step collection and enrichment of aerosolized polystyrene microparticles into a flowing liquid using a stratified air-water flow in a U-shaped microchannel. We validate our simulation results by comparing them to experimental data from the literature. Additionally, we fabricate an identical microfluidic device using PDMS-based soft lithography and test it to corroborate the previously published experimental data. Diversion and entrapment efficiencies are used as evaluation metrics, both of which increase with increasing particle diameter and superficial air inlet velocity. Overall, our ANSYS Fluent two-dimensional (2D) and three-dimensional (3D) multiphase flow simulations exhibit a good agreement with our experimental data and data in the literature (average deviation of ∼11%) in terms of diversion efficiency. Simulations also found the entrapment efficiency to be lower than the diversion efficiency, indicating discrepancies in the literature in terms of captured particles. The effect of the Dean force on the flow physics was also investigated using 3D simulations. We found that the effect of the Dean flow was more dominant relative to the centrifugal force on the smaller particles (e.g., 0.65 μm) compared to the larger particles (e.g., 2.1 μm). Increasing the superficial air inlet velocity also increases the effect of the centrifugal forces relative to the Dean forces. Overall, this experimentally validated multiphase model decouples and investigates the multiple and simultaneous forces on aerosolized particles flowing through a curved microchannel, which is crucial for designing more efficient capture devices. Once integrated with a microfluidic-based biosensor, this stratified flow-based microfluidic biothreat capture platform should deliver continuous sensor-ready enriched biosamples for real-time sensing.
Topics: Aerosols; Polystyrenes; Particle Size; Microfluidic Analytical Techniques; Lab-On-A-Chip Devices; Microfluidics
PubMed: 38848499
DOI: 10.1021/acssensors.4c00042 -
Trends in Biotechnology Feb 2013A recent development, inspired by nature, is the use of 'artificial cilia' to create pumping and/or mixing in microfluidic devices. Cilia are small hairs that can be... (Review)
Review
A recent development, inspired by nature, is the use of 'artificial cilia' to create pumping and/or mixing in microfluidic devices. Cilia are small hairs that can be found in biology and are used for (fluid) actuation and sensing. Microscopic actuators resembling cilia, actuated to move under the influence of various stimuli such as electrostatic field, magnetic field, and even light, have been developed by a number of groups and shown to be capable of generating flow and mixing in microfluidic environments. The research on artificial cilia started about a decade ago and is rapidly expanding. In addition to being relevant for potential application in lab-on-a-chip devices, the work on artificial cilia forms a beautiful example of how a biological system can form the successful basis for both scientific research and technological applications. In this review, we will give an overview of the most important approaches in this exciting field.
Topics: Artificial Cells; Cilia; Hydrogels; Lab-On-A-Chip Devices; Magnetic Fields; Microfluidic Analytical Techniques; Microfluidics; Models, Theoretical; Optics and Photonics; Static Electricity
PubMed: 23245658
DOI: 10.1016/j.tibtech.2012.11.005 -
Analytical and Bioanalytical Chemistry Jun 2012The application of microfluidic droplet PCR for single-molecule amplification and analysis has recently been extensively studied. Microfluidic droplet technology has the... (Review)
Review
The application of microfluidic droplet PCR for single-molecule amplification and analysis has recently been extensively studied. Microfluidic droplet technology has the advantages of compartmentalizing reactions into discrete volumes, performing highly parallel reactions in monodisperse droplets, reducing cross-contamination between droplets, eliminating PCR bias and nonspecific amplification, as well as enabling fast amplification with rapid thermocycling. Here, we have reviewed the important technical breakthroughs of microfluidic droplet PCR in the past five years and their applications to single-molecule amplification and analysis, such as high-throughput screening, next generation DNA sequencing, and quantitative detection of rare mutations. Although the utilization of microfluidic droplet single-molecule PCR is still in the early stages, its great potential has already been demonstrated and will provide novel solutions to today's biomedical engineering challenges in single-molecule amplification and analysis.
Topics: Animals; DNA; Emulsions; Equipment Design; High-Throughput Nucleotide Sequencing; Humans; Microfluidics; Polymerase Chain Reaction
PubMed: 22451171
DOI: 10.1007/s00216-012-5914-x -
Current Opinion in Neurobiology Oct 2010The precise spatial and temporal control afforded by microfluidic devices make them uniquely suited as experimental tools for cellular neuroscience. Micro-structures... (Review)
Review
The precise spatial and temporal control afforded by microfluidic devices make them uniquely suited as experimental tools for cellular neuroscience. Micro-structures have been developed to direct the placement of cells and small organisms within a device. Microfluidics can precisely define pharmacological microenvironments, mimicking conditions found in vivo with the advantage of defined parameters which are usually difficult to control and manipulate in vivo. These devices are compatible with high-resolution microscopy, are simple to assemble, and are reproducible. In this review we will focus on microfluidic devices that have recently been developed for small, whole organisms such as C. elegans and dissociated cultured neurons. These devices have improved control over the placement of cells or organisms and allowed unprecedented experimental access, enabling novel investigations in neurobiology.
Topics: Animals; Humans; Microfluidic Analytical Techniques; Microfluidics; Models, Animal; Neurobiology; Neurons
PubMed: 20739175
DOI: 10.1016/j.conb.2010.07.011 -
Lab on a Chip May 2009Multiple advantages of microfluidics have been demonstrated in the area of organic synthesis. However, only a limited number of them have found applications in... (Review)
Review
Multiple advantages of microfluidics have been demonstrated in the area of organic synthesis. However, only a limited number of them have found applications in radiopharmaceutical synthesis, while that is an area where the need for improvements offered by microfluidics is very significant. The need is to create an environment where all reactions involving short-lived radioisotopes such as (18)F (110 min half-life) or (11)C (20 min half-life) are rapid and high-yielding while the devices are controlled remotely. Several groups have identified the potential of microfluidics in this area and have demonstrated that various steps of conventional radiosynthesis can be replaced by microfluidic devices. However, despite promising results that stir up the interest in the scientific community, none of these inventions has found commercial applications with broad use yet. This article will review the technologies reported to date and analyze the unmet needs that will have to be addressed before microfluidic technology has a chance of becoming a viable and truly advantageous method of preparation of commercial radiopharmaceuticals. The latter mostly center around Positron Emission Tomography (PET) biomarkers.
Topics: Biomarkers, Pharmacological; Equipment Design; Microfluidics; Positron-Emission Tomography; Radioisotopes; Radiopharmaceuticals
PubMed: 19417895
DOI: 10.1039/b820299k