Showing papers on "Fluidics published in 2019"

A micro-dispenser for long-term storage and controlled release of liquids.

Abstract: The success of lab-on-a-chip systems may depend on a low-cost device that incorporates on-chip storage and fluidic operations. To date many different methods have been developed that cope separately with on-chip storage and fluidic operations e.g., hydrophobic and capillary valves pneumatic pumping and blister storage packages. The blister packages seem difficult to miniaturize and none of the existing liquid handling techniques despite their variety are capable of proportional repeatable dispensing. We report here on an inexpensive robust and scalable micro-dispenser that incorporates long-term storage and aliquoting of reagents on different microfluidics platforms. It provides long-term shelf-life for different liquids enables precise dispensing on lab-on-a-disc platforms and less accurate but proportional dispensing when operated by finger pressure. Based on this technology we introduce a method for automation of blood plasma separation and multi-step bioassay procedures. This micro-dispenser intends to facilitate affordable portable diagnostic devices and accelerate the commercialization of lab-on-a-chip devices.

Microfluidic Pump Driven by Anisotropic Phoresis

Abstract: One of the most challenging goals of microfluidics is the design of devices that can efficiently and precisely guide the movement of fluid at the nano- and microscales. This work proposes channels with elongated tilted obstacles in between, which, under the effect of a transverse gradient in temperature or concentration, can generate net fluid motion along the channels. Simulations show that flow properties are determined not only by the applied gradient and obstacle orientation, but also by the obstacle's intrinsic surface characteristics. Applications would include fluidic mixers and alternators, also with the potential to harvest waste heat or chemical energy.

Bio-O-Pump: a novel portable microfluidic device driven by osmotic pressure

Abstract: The concepts of lab on a chip, miniaturised fluidic systems, and biochips entail the use of a fluid to perform analogue or digital operations. The temporal and spatial fluidic drive and control in microfluidic systems usually involves a complex pump, tubing, and connection system. Reducing the number of external components is crucial for use by scientists without an engineering background. In this paper, we present a novel pump-free device that uses an osmotic-pressure-driven flow to control and modulate fluid flow in microfluidic networks. The flow rate was regulated by controlling the osmotic area and the concentration of the draw solution, which comprised an easily accessible solution of electrolytes such as commercial sterile saline buffer and sodium chloride solution. The Bio-O-Pump can continuously generate liquid movement up to a flow rate of 4.88 mL h−1 over 1 h. This research also presents a single cell trapping application for biomedical uses.

Fluid Flow Characteristics of a Co-Flow Fluidic Slot Jet Thrust Augmentation Propulsion System

Abstract: The UAV industry is booming with investments in research and development on improving UAV systems. Current UAV machines are developed according to the quadcopter design which consists of a rotary propulsion system providing lift needed for flight. This design has some flaws; namely safety concerns and noise/vibration production both of which come stem from the rotary propulsion system. As such, a novel propulsion system using slip stream air passed through high performance slot jets is proposed and an analysis of the fluid characteristics is presented in this report. The test section for the experiment is developed using 3D printed ABS plastic airfoils modified with internal cavities where pressurized air is introduced and then expelled through slot jets on the pressure side of the airfoils. Entrainment processes develop in the system through high momentum fluid introduction into a sedentary secondary fluid. Entrainment is governed by pressure gradients and turbulent mixing and so turbulent quantities that measure these processes are extracted and analyzed according to the independent variable’s effects on these quantities. Pitot probe testing extracted one dimensional fluid information and PIV analysis is used to characterize the two-dimensional flow aspects. High slot jet velocities are seen to develop flows dominated by convection pushing momentum mixing downstream reducing the mixing in the system while low slot jet speeds exhibit higher mass fluxes and thrust development. Confinement spacing is seen to cause a decrease in flow velocity and thrust as the spacing is decreased for high speed runs. The most constricted cross sectional runs showed high momentum mixing and developed combined self-similar flow through higher boundary layer interactions and pressures, but this also hurts thrust development by minimizing secondary flows. The Angle of Attack of the assembly proved to be the most important variable. Outward angling showed the influence of coanda effects but also demonstrated the highest bulk fluid flow with turbulence driven momentum mixing. Inward angling created combined fluid flow downstream with high momentum mixing upstream driven by pressure. Minimal mixing is seen when the airfoils are not angled, and high recirculation zones occur along the boundaries. The optimal setup is seen when the airfoils are angled outwards where the highest thrust and bulk fluid movement is developed driven by the turbulent mixing induced by the increasing cross sectional area of the system.

An analytical interface shape approximation of microscopic Taylor flows

Abstract: This paper presents a geometric model to approximate the interface shape of Taylor bubbles and droplets moving in rectangular microchannels. To retrieve the entire 3D interface geometry, the following apriori knowledge is required: the cross-sectional channel geometry, the droplet/bubble length, and the flow-related front and back cap deformation ratios retrieved, e.g., from instantaneous images of translating interfaces. The accuracy of the interface shape model is benchmarked with experimentally generated average images of the statistical distribution of a particulate tracer. In the experiment, the fluidic material system, the aspect ratio of the channel cross section, and the droplet/bubble length are varied. The mean overall deviation between the model and the experimental data remains below $$2\%$$ . The interface shape model is applicable for horizontal pressure-driven liquid–liquid and gas–liquid fluid systems in a range of Ca $$< 0.01$$ , $$Re \lesssim 1$$ and $$Bo \ll 1$$ with the liquid continuous phase wetting the wall. The model can be applied, e.g., to guide the 3D flow field reconstruction of multi-plane $$\upmu$$ -PIV measurements of Taylor flows.

Passive microscopic fluidic diodes using asymmetric channels

Abstract: In this paper, we propose a passive microscopic fluidic diodes with no moving parts for simple fluids using asymmetric channel structures. Finite element simulations demonstrate that the fluidic diode conducts water flows preferentially in one forward direction while blocks flows in the reverse direction in a wide pressure range. The exceptional rectification performance is owing to the anisotropic direction-dependent activation pressures. In the forward direction, the activation pressure is small, which is controlled by the infiltration pressure of the small channel. In the backward direction, the activation pressure is large due to the high release pressure at the channel exit. The effective working pressure range for the fluidic diode can be flexibly adjusted by modifying the channel size or the surface property. Furthermore, we create a microfluidic diode fabricated on silicon membranes using laser direct writing. The diode achieves flow rectifications in a certain pressure range, which confirms the underlying rectification mechanisms. This work provides a novel strategy for flow control or logic computations in integrated micro- and nanofluidic systems.

3D-Integration of Printed Electrochemical Sensors in Pet Microfluidics for Biochemical Sensing

Abstract: This paper presents a novel process for screen printed electrode fabrication, functionalization and integration in a polyethylene terephthalate (PET) fluidics system for electrochemical analysis. The innovative components utilized are: 1. 3D Through-Foil Vias (TFVs) for electrode connection, enabling simple liquid tight lamination of micro-fluidic channels; 2. Screen printed carbon and silver/silver chloride (Ag/AgCl) electrodes on 3D vias; and 3. PET fluidics with a fabrication process compatible with large-area manufacturing. A platform integrating an Ag/AgCl pseudo-reference and a glucose oxidase (GOx)-modified working electrode has been used for glucose sensing in the flexible fluidics system. Detection of small glucose concentrations between 100-400 μM through Cyclic Voltammetry (CV) is shown. The sensor shows linear response and good sensitivity of ~0.8 mA/(mM cm2). By changing the electrode coatings, the same technology can potentially be used for detecting multiple analytes in biofluids.

Micro- and Meso-fluidics for Automated Biomedical Sample Preparation

Abstract: of Microand Meso-fluidics for Automated Biomedical Sample Preparation, by Francis R. Cui, Ph.D., Brown University, May 2019. The past quarter-century of biomedical research has seen the emergence of powerful and transformational methods such as quantitative polymerase chain reaction, next generation sequencing, and 3D cell culture. Though impressive in their capabilities and tantalizing in their potential, these highly sophisticated technologies are still hampered by the same persisting problem—sample preparation. Procedures such as nucleic acid purification remain manual, laborious and susceptible to human error, while newer technologies like 3D tissue self-assembly do not yet even have solutions for microtissue handling other than manual pipetting for sub-millimeter spheroids. Microfluidics, or automated liquid handling at the very small scale, represents a promising approach for developing new fluidic platforms that can handle the demands of sample preparation: high yield, purity, and robustness. This thesis aims to explore robust microand mesofluidic technologies with two main focuses: studying and automating the transport of microtissues and microparticles, and improving upon conventional biomolecular purification procedures. Particle suspensions within pressure-driven flows are investigated to measure their shear-induced evolution and axial dispersion. Novel fluidic platforms are also designed, implemented and analyzed, including the hydrodynamic characterization of a ‘Bio-Gripper’ for automated microtissue translocation, the application of oil-water interfaces for extracting influenza RNA from clinical samples, and the magnetoelectrophoretic transport and purification of DNA for next generation sequencing library preparation. These technologies may serve to streamline sample preparation, reduce procedural time and human error, and thus bring about a more rapid “sample in, result out” paradigm in the biomedical space.

Modular interface and experimental setup for in-vacuum operation of microfluidic devices.

Abstract: We report on the design and operation of a world-to-chip microfluidic interface and experimental setup for fluidic micro- and nano-electromechanical systems. The central component of the interface is an engineered polyether ether ketone connector that brings fluid samples from a commercial syringe pump to the chip with the help of o-rings. In addition to that, the connector serves as an on-chip vacuum chamber. To confirm the adequate operation of our interface, we use complex microfluidic devices that were previously fabricated, suspended microchannel resonators, and demonstrate a fast exchange between fluids (on the scale of 130 s from isopropyl alcohol to water), in-vacuum operation of the devices (intrinsic damping regime), and accurate temperature control of the chip at different set points.

Development of a Passive Capacitively Coupled Contactless Conductivity Detection (PC4D) Sensor System for Fluidic Channel Analysis Toward Point-of-Care Applications

Abstract: A sensor system based on a modified capacitively coupled contactless conductivity detection sensor is proposed and developed. The proposed system provides a passive and wireless readout technique, through which the conductivity of fluidic flow can be analyzed and foreign objects occurring in the fluidic flow can be detected. The proposed sensor system takes advantage of the series resonance principle and detects shifts in the resonance frequency and reflection coefficient to estimate the conductivity of the fluidic flow. In this paper, the working principle of the device is proposed and analyzed using a multiphysics simulation, and its performance is validated experimentally. The sensing performance is confirmed by measuring the conductivity of the fluidic media and the detection of foreign objects, such as air bubbles or water droplets, occurring in the flow. The influence of the distance between the inductors on the resonance frequency for different solution conductivities is also investigated and reported. The proposed sensor system shows its potential for use in various applications in biomedicine and chemistry, particularly in point-of-care applications, where the sensing chip can be easily set up for measurement and disposed of after use.

The design and manufacturing of fluidic oscillators for composite aircraft structures

Abstract: Active flow control devices have been proven to reduce drag and delay stall on commercial aircraft. This leads to lower fuel usage and thus reduced flight costs. However, there is a large uncertain...

Assessment of two fluidic actuators for active flow control on a one-sided diffuser

Abstract: The manipulated flow along a one-sided diffuser is investigated experimentally by means of particle image velocimetry and wall pressure measurements. Two fluidic actuators are considered: a fluidic diverter emitting two alternately pulsed jets and a fluidic oscillator generating one spatially oscillating jet. Active separation control is performed with these devices to suppress the pressure-induced separation bubble present in the uncontrolled flow field. The method of proper orthogonal decomposition is employed to identify inherent physical mechanisms subject to varied jet emission angles as well as actuation intensities and construct a reduced order model by utilizing modal coefficients to obtain phase information regarding the periodic actuation process. As a main result, we show that longitudinal vortex structures determining the separation control capability, are more distinct for the fluidic oscillator. Furthermore, the flow fields manipulated by both actuators at a low momentum input are dominated by a spatial mode resembling the base flow. However, this feature is suppressed by the fluidic diverter at greater velocity ratios, whereas the variation of actuation intensity does not yield significant alterations to the spatial modes observed for the fluidic oscillator.

Valveless Microfluidic Flow Control Using Planar Fresnel Type GHz Ultrasonic Transducers

Abstract: Localized microfluidic flow control using a 1×4 linear array of Fresnel type GHz ultrasonic transducers is presented. The planar fabrication process and the decoupling of fluidics from the electrical interconnects side of the aluminum nitride based transducer enable easier integration of GHz transducers and fluidics in a distributed manner. The streaming vortices generated by the high frequency focused sonic waves from the Fresnel transducers perturb the laminar nature of the microfluidic flow in the channel. By electronically controlling the on and off times of the RF signal inputs to the Fresnel transducers, fluidic steaming was localized. Further, the changes in the path of polystyrene microbeads in water that were pumped into the microchannel indicate changes in the fluidic forces acting on them due to acoustic streaming and change in the flow velocity.

Micro -fluidic chip switching device

Abstract: The utility model relates to a little valve control pneumatic system technical field especially relates to a micro -fluidic chip switching device. A micro -fluidic chip switching device, includes thebase and approximately locates lid on the base, the lid with base sealing connection, be used for setting up micro -fluidic chip between base and the lid, be equipped with on base or the lid for withthe electrode extraction structure that micro -fluidic chip electrode interface matches, electrode extraction structure be used for with the last electrode of micro -fluidic chip is drawn forth, the base is offered at least one on or and is used the connector for the fluid flow, the connector with the micro -fluidic chip valve port is corresponding match one by one. The utility model has the advantages of: will through motor extraction structure the last electrode of micro -fluidic chip is drawn forth, the valve port is switchoverred to the connector to realize micro -fluidic chip and externalcircuit and tube coupling, not only simple structure, processing convenience and with low costs have extensive application prospect.

Using Fluidic Devices To Estimate Cut of Wellbore Fluids

Abstract: A method includes directing a wellbore fluid into a flow control assembly coupled to a completion string positioned within a wellbore, the flow control assembly including at least a first fluidic device defining a flow passage, where the flow passage is formed of a material having a known wettability selected to correspond to a component of the wellbore fluid. The pressure change along the flow passage is measured and utilized to determine fluid cut based on a predetermined correspondence between pressure change and component cut for the first fluidic device. Multiple fluidic devices, each selected to have a wettability responsive to a different component of the wellbore fluid, may be aligned in parallel or series to determine the cut of multiple components in the fluid.

Integrated fluidic circuit and device for droplet manipulation and methods thereof

Abstract: Various embodiments of fluidic devices and methods of the present teaching can provide precision on-device loading of fluidic samples, and merging, mixing, and splitting of the fluidic samples, in illustrative embodiments as droplets, using pressures that can be provided by standard laboratory liquid handling equipment. Various embodiments of fluidic devices of the present teachings can provide on device manipulation of accurate and precise fluidic volumes at the picoliter to nanoliter scale for each steps from fluidic sample loading to fluidic sample splitting. Various embodiments of fluidic elements of the present teachings, for example, but not limited by, various embodiments of fluidic traps of the present teachings, can have a constrained and measurable geometry, allowing for accurate and precise tuning of each fluidic sample volume throughout the on-device liquid handling process.

Delay elements for activation signals

Abstract: In some examples, a fluidic die includes a plurality of fluid actuators, and a controller to determine, based on input control information relating to controlling actuation of the plurality of fluid actuators, whether a first fluid actuator of the plurality of fluid actuators is to be actuated, and in response to determining that the first fluid actuator is to be actuated, activate a delay element associated with the first fluid actuator, the delay element to delay an activation signal propagated to selected fluid actuators of the plurality of fluid actuators in response to an actuation event.

Frequency-synchronized fluidic oscillator array

Abstract: Various implementations include a fluidic oscillator array including at least two fluidic oscillators, each including an interaction chamber, fluid supply inlet, outlet nozzle, and feedback channels. The interaction chambers have a first and second attachment wall. Fluid streams flow from the fluid supply inlets, into the interaction chambers, and exit through the outlet nozzles. A feedback channel is coupled to each of the first and second attachment walls. Each feedback channel is in fluid communication with the interaction chamber and has an intermediate portion disposed between a first and second end of the feedback channels. Fluid from the fluid stream flows into the first ends of the respective feedback channels, causing the fluid stream to oscillate between the first and second attachment walls. Adjacent feedback channels of adjacent fluidic oscillators share a common intermediate portion, causing the exiting fluid streams of each fluidic oscillator to oscillate at the same frequency.

Rheologically biomimetic fluid surrogate

Abstract: The present invention contemplates compositions, devices and methods of simulating biological fluids in a fluidic device, including but not limited to a microfluidic chip. In one embodiment, fluid comprising a colloid under flow in a microfluidic chip has a fluid density or viscosity similar to a bodily fluid, e.g. blood, lymph, lung fluid, or the like. In one embodiment, a fluid is provided as a Theologically biomimetic blood surrogate or substitute for simulating physiological shear stress and cell dynamics in fluidic device, including but not limited to immune cells.

Inertial pump fluid dispensing

Abstract: A fluidic device may include a vertical fluid dispensing volume having a side outlet, a fluid channel connected to the vertical fluid dispensing volume below the side outlet and a fluid actuator asymmetrically located between ends of the fluid channel to form an inertial pump to vertically pump fluid within the channel to the side outlet.

Fluid actuator evaluation independent of actuation state

Abstract: In one example in accordance with the present disclosure, a fluidic die is described. The fluidic die includes an array of fluid actuators grouped into primitives. The fluidic die also includes a fluid actuator controller to selectively activate fluid actuators via activation data. The fluidic die also includes an array of actuator evaluators, wherein each actuator evaluator of the fluidic die is coupled to a subset of the array of fluid actuators. The actuator evaluators selectively evaluate an actuator characteristic of a selected fluid actuator based on: an output of an actuator sensor paired with the selected fluid actuator, the activation data, and an evaluation control signal.

Electrical energy generation in fluidic channels and membranes using spontaneous capillary flow

Abstract: Described herein are systems and methods for the generation of electric current and/or electric potential utilizing micro- or nano-channels and capillary flow, including fluidic or microfluidic batteries and electrochemical cells. The provided systems and methods use capillary force to promote fluid flow through micro- and nano-fluidic channels by evaporating fluid at one terminus of the channel, and the resulting fluid flow generates electric potential and or current. Advantageously, the described systems and methods remove the need for pressurized vessels or external pumps, increasing net energy generation and decreasing complexity and size of potential fluidic batteries.

Three-dimensional micro-electro-mechanical, microfluidic, and micro-optical systems

Abstract: Various three-dimensional devices that can be formed within the bulk of a semiconductor by photo-controlled selective etching are described herein. With more particularity, semiconductor devices that incorporate three-dimensional electrical vias, waveguides, or fluidic channels that are disposed within a semiconductor are described herein. In an exemplary embodiment, a three-dimensional interposer chip includes an electrical via, a waveguide, and a fluidic channel, wherein the via, the waveguide, and the fluidic channel are disposed within the body of a semiconductor element rather than being deposited on a surface. The three-dimensional interposer is usable to make electrical, optical, or fluidic connections between two or more devices.

System and Method for Separation Gas Detection Between Samples

Abstract: A flow cytometer apparatus is provided herein including (a) a flow cell, (b) a fluidic pathway having a second end coupled to a first end of the flow cell, (c) a probe coupled to a first end of the fluidic pathway, (d) at least one sensor configured to detect one or more properties of a fluid in the fluidic pathway and positioned between the probe and the first end of the flow cell, (e) a processor in communication with the at least one sensor, and (f) a non-transitory computer readable medium having stored therein instructions that are executable to cause the processor to perform functions including: (i) receiving, via the processor, the one or more properties of the fluid in the fluidic pathway detected by the at least one sensor, and (ii) determining, based on the detected one or more properties of the fluid in the fluidic pathway, a presence of a separation gas in the fluid in the fluidic pathway.