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In JoVE (1)
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Articles by Jon F. Edd in JoVE
JoVE Bioengineering
Высокая пропускная способность Single-камеру и несколько клеток микро-инкапсуляции
Department of Mechanical Engineering, Vanderbilt University
Объединение монодисперсных падение поколения с инерционным порядком клеток и частиц, описывается метод инкапсуляции нужное количество клеток или частиц в одной капле в кГц ставки. Мы демонстрируем эффективность в два раза превышающие неупорядоченных инкапсуляции для одно-и двух-частиц падает.
Other articles by Jon F. Edd on PubMed
Equilibrium Separation and Filtration of Particles Using Differential Inertial Focusing
Rapid separation and filtration of particles in solution has a wide range of applications including blood cell separation, ultrasound contrast agent preparation, and purification of fermentation products. However, current techniques that provide quick processing rates are high in complexity. We present a rapid microfluidic filtration technology capable of separating particles based on size, with purities from 90 to 100% and high-volume throughputs of 1 mL/min. Data for separation of rigid particles, deformable emulsions, and platelets from whole blood are presented. The system is based upon differential inertial focusing of particles of varying sizes and allows continuous separation based only on intrinsic hydrodynamic forces developed in a flow through an asymmetrically curved channel. A theoretical description of the underlying forces is developed, and in combination with data determining a size cutoff for separation, a semiempirical relationship describing how channel geometry is related to this cutoff is shown. Cascading separations in series is shown to be useful for increasing purity and yield. This type of microfluidic system can filter deformable particles, is largely independent of particle density, and can provide throughputs typical of macroscale filtration in a compact format, enabling applications in blood filtration and particle concentration.
Controlled Encapsulation of Single-cells into Monodisperse Picolitre Drops
Encapsulation of cells within picolitre-size monodisperse drops provides new means to perform quantitative biological studies on a single-cell basis for large cell populations. Variability in the number of cells per drop due to stochastic cell loading is a major barrier to these techniques. We overcome this limitation by evenly spacing cells as they travel within a high aspect-ratio microchannel; cells enter the drop generator with the frequency of drop formation.
Particle Segregation and Dynamics in Confined Flows
Nonlinearity in finite-Reynolds-number flow results in particle migration transverse to fluid streamlines, producing the well-known "tubular pinch effect" in cylindrical pipes. Here we investigate these nonlinear effects in highly confined systems where the particle size approaches the channel dimensions. Experimental and numerical results reveal distinctive dynamics, including complex scaling of lift forces with channel and particle geometry. The unique behavior described in this Letter has broad implications for confined particulate flows.
Nucleation and Solidification in Static Arrays of Monodisperse Drops
The precise measurement of nucleation and non-equilibrium solidification are vital to fields as diverse as atmospheric science, food processing, cryopreservation and metallurgy. The emulsion technique, where the phase under study is partitioned into many droplets suspended within an immiscible continuous phase, is a powerful method for uncovering rates of nucleation and dynamics of phase changes as it isolates nucleation events to single droplets. However, averaging the behavior of many drops in a bulk emulsion leads to the loss of any drop-specific information, and drop polydispersity clouds the analysis. Here we adapt a microfluidic technique for trapping monodisperse drops in planar arrays to characterize solidification of highly supercooled aqueous solutions of glycerol. This system measured rates of nucleation between 10(-5) and 10(-2) pL(-1) s(-1), yielded an ice-water interfacial energy of 33.4 mJ m(-2) between -38 and -35 degrees C, and enabled the specific dynamics of solidification to be observed for over a hundred drops in parallel without any loss of specificity. In addition to the physical insights gained, the ability to observe the time and temperature of nucleation and subsequent growth of the solid phase in static arrays of uniform drops provides a powerful tool to discover thermodynamic protocols that generate desirable crystal structures.
Differential Inertial Focusing of Particles in Curved Low-aspect-ratio Microchannels
Microfluidic-based manipulation of particles is of great interest due to the insight it provides into the physics of hydrodynamic forces. Here, we study a particle-size-dependent phenomenon based on differential inertial focusing that utilizes the flow characteristics of curved, low aspect ratio (channel width ≫ height), microfluidic channels. We report the emergence of two focusing points along the height of the channel (z-plane), where different sized particles are focused and ordered in evenly spaced trains at correspondingly different lateral positions within the channel cross-section. We applied the system for continuous ordering and separation of suspension particles.
Concentration of Glycerol in Aqueous Microdroplets by Selective Removal of Water
A major roadblock to the vitrification of cells is the requirement of high concentrations of cryoprotectant (CPA) chemicals and the damage caused by prolonged exposure of cells to these high concentrations above the glass transition temperature. These effects are minimized with controlled CPA loading. Certain organic oils, such as soybean oil, are made of triacylglycerols and are capable of dissolving small amounts of water, a property which is enhanced significantly as temperature is increased. This phenomenon was exploited here to accomplish temperature-controlled concentration of glycerol in single water droplets dispersed in the organic phase. Emulsions of aqueous solutions of glycerol in soybean oil were made and subjected to a temperature increase of 10 degrees C from room temperature. Upon increasing temperature, water dissolved into the oil, rendering the 15-20 microm droplets concentrated an average of 3.6 times and 2.6 times for 1 and 2 M starting concentrations, respectively, with the oil-insoluble glycerol in 90-110 s. This phenomenon could be used to dynamically concentrate CPAs within cell-containing droplets which may then be vitrified before being exposed to high temperatures for fatally long times.
