Storing and releasing rhodamine as a model hydrophobic compound in polydimethylsiloxane microfluidic devices

Lab on a Chip ◽  
2019 ◽  
Vol 19 (4) ◽  
pp. 574-579 ◽  
Author(s):  
M. Adiraj Iyer ◽  
D. T. Eddington
Keyword(s):  
Microfluidic Device ◽  
Microfluidic Devices ◽  
Microfluidic Channels ◽  
Hydrophobic Compound ◽  
Small Hydrophobic

Polydimethylsiloxane (PDMS) is known to absorb small hydrophobic molecules. We propose to leverage this material to store and release small hydrophobic molecules into and from the PDMS matrix. This method could be used to deliver small hydrophobic molecules to microfluidic channels from the walls of a microfluidic device.

scholarly journals ZnO Nanowire-Anchored Microfluidic Device With Herringbone Structure Fabricated by Maskless Photolithography

2020 ◽  
Vol 11 ◽  
pp. 117959722094143
Author(s):  
Dilshan Sooriyaarachchi ◽  
Shahrima Maharubin ◽  
George Z Tan
Keyword(s):  
Turbulent Flows ◽  
Microfluidic Device ◽  
High Efficiency ◽  
Kidney Diseases ◽  
Microfluidic Devices ◽  
Zno Nanowires ◽  
Nanowire Arrays ◽  
Microfluidic Channels ◽  
Zno Nanowire ◽  
Zno Nanowire Arrays

The integration of nanomaterials in microfluidic devices has emerged as a new research paradigm. Microfluidic devices composed of ZnO nanowires have been developed for the collection of urine extracellular vesicles (EVs) at high efficiency and in situ extraction of various microRNAs (miRNAs). The devices can be used for diagnosing various diseases, including kidney diseases and cancers. A major research need for developing micro total analysis systems is to enhance extraction efficiency. This article presents a novel fabrication method for a herringbone-patterned microfluidic device anchored with ZnO nanowire arrays. The substrates with herringbone patterns were created by maskless photolithography. The ZnO nanowire arrays were grown on the substrates by chemical bathing. The patterned design was to introduce turbulent flows as opposed to laminar flow in traditional devices to increase the mixing and contact of the urine sample with ZnO nanowires. The device showed reduced flow rates compared with conventional planar microfluidic channels and successfully extracted urine EV-encapsulated miRNAs.

scholarly journals Slicing Spheroids in Microfluidic Devices for Morphological and Immunohistochemical Analysis

Micromachines ◽  
2020 ◽  
Vol 11 (5) ◽  
pp. 480 ◽  
Author(s):  
Satoru Kuriu ◽  
Tetsuya Kadonosono ◽  
Shinae Kizaka-Kondoh ◽  
Tadashi Ishida
Keyword(s):  
Microfluidic Device ◽  
Microfluidic Devices ◽  
Immunohistochemical Analysis ◽  
Specific Protein ◽  
Cellular Level ◽  
Microfluidic Channels ◽  
Protein Distribution ◽  
Experimental Systems

Microfluidic devices utilizing spheroids play important roles in in vitro experimental systems to closely simulate morphological and biochemical characteristics of the in vivo tumor microenvironment. For the observation and analysis of the inner structure of spheroids, sectioning is an efficient approach. However, conventional microfluidic devices are difficult for sectioning, and therefore, spheroids inside the microfluidic channels have not been sliced well. We proposed a microfluidic device created from embedding resin for sectioning. Spheroids were cultured, embedded by resin, and sectioned in the microfluidic device. Slices of the sectioned spheroids yielded clear images at the cellular level. According to morphological and immunohistochemical analyses of the slices of the spheroid, specific protein distribution was observed.

scholarly journals A Compact, Syringe-Assisted, Vacuum-Driven Micropumping Device

Micromachines ◽  
2019 ◽  
Vol 10 (8) ◽  
pp. 543 ◽  
Author(s):  
Anyang Wang ◽  
Domin Koh ◽  
Philip Schneider ◽  
Evan Breloff ◽  
Kwang W. Oh
Keyword(s):  
Microfluidic Device ◽  
Point Of Care ◽  
Microfluidic Devices ◽  
Microfluidic Channels ◽  
Constant Flow ◽  
Proof Of Concept ◽  
Point Of Care Testing ◽  
Microfluidic Mixing ◽  
Pumping System ◽  
Dead End

In this paper, a simple syringe‑assisted pumping method is introduced. The proposed fluidic micropumping system can be used instead of a conventional pumping system which tends to be large, bulky, and expensive. The micropump was designed separately from the microfluidic channels and directly bonded to the outlet of the microfluidic device. The pump components were composed of a dead‑end channel which was surrounded by a microchamber. A syringe was then connected to the pump structure by a short tube, and the syringe plunger was manually pulled out to generate low pressure inside the microchamber. Once the sample was loaded in the inlet, air inside the channel diffused into the microchamber through the PDMS (polydimethylsiloxane) wall, acting as a dragging force and pulling the sample toward the outlet. A constant flow with a rate that ranged from 0.8 nl · s − 1 to 7.5 nl · s − 1 was achieved as a function of the geometry of the pump, i.e., the PDMS wall thickness and the diffusion area. As a proof-of-concept, microfluidic mixing was demonstrated without backflow. This method enables pumping for point-of-care testing (POCT) with greater flexibility in hand-held PDMS microfluidic devices.

scholarly journals Micropipette-Based Microfluidic Device for Monodisperse Microbubbles Generation

Micromachines ◽  
2018 ◽  
Vol 9 (8) ◽  
pp. 387
Author(s):  
Carlos Toshiyuki Matsumi ◽  
Wilson José da Silva ◽  
Fábio Kurt Schneider ◽  
Joaquim Miguel Maia ◽  
Rigoberto E. M. Morales ◽  
...  
Keyword(s):  
Electric Fields ◽  
Microfluidic Device ◽  
Soft Lithography ◽  
Low Cost ◽  
Characteristic Curve ◽  
Microfluidic Devices ◽  
Average Diameter ◽  
Internal Diameter ◽  
Medical Diagnostic ◽  
Average Size

Microbubbles have various applications including their use as carrier agents for localized delivery of genes and drugs and in medical diagnostic imagery. Various techniques are used for the production of monodisperse microbubbles including the Gyratory, the coaxial electro-hydrodynamic atomization (CEHDA), the sonication methods, and the use of microfluidic devices. Some of these techniques require safety procedures during the application of intense electric fields (e.g., CEHDA) or soft lithography equipment for the production of microfluidic devices. This study presents a hybrid manufacturing process using micropipettes and 3D printing for the construction of a T-Junction microfluidic device resulting in simple and low cost generation of monodisperse microbubbles. In this work, microbubbles with an average size of 16.6 to 57.7 μm and a polydispersity index (PDI) between 0.47% and 1.06% were generated. When the device is used at higher bubble production rate, the average diameter was 42.8 μm with increased PDI of 3.13%. In addition, a second-order polynomial characteristic curve useful to estimate micropipette internal diameter necessary to generate a desired microbubble size is presented and a linear relationship between the ratio of gaseous and liquid phases flows and the ratio of microbubble and micropipette diameters (i.e., Qg/Ql and Db/Dp) was found.

scholarly journals Manufacturing of Microfluidic Devices with Interchangeable Commercial Fiber Optic Sensors

Sensors ◽  
2021 ◽  
Vol 21 (22) ◽  
pp. 7493
Author(s):  
Krystian L. Wlodarczyk ◽  
William N. MacPherson ◽  
Duncan P. Hand ◽  
M. Mercedes Maroto-Valer
Keyword(s):  
Porous Structure ◽  
Steady Flow ◽  
Microfluidic Device ◽  
Fiber Optic ◽  
Dynamic Pressure ◽  
Pressure Sensors ◽  
Microfluidic Devices ◽  
Fiber Optic Sensors ◽  
Valuable Insight ◽  
Local Pressure

In situ measurements are highly desirable in many microfluidic applications because they enable real-time, local monitoring of physical and chemical parameters, providing valuable insight into microscopic events and processes that occur in microfluidic devices. Unfortunately, the manufacturing of microfluidic devices with integrated sensors can be time-consuming, expensive, and “know-how” demanding. In this article, we describe an easy-to-implement method developed to integrate various “off-the-shelf” fiber optic sensors within microfluidic devices. To demonstrate this, we used commercial pH and pressure sensors (“pH SensorPlugs” and “FOP-MIV”, respectively), which were “reversibly” attached to a glass microfluidic device using custom 3D-printed connectors. The microfluidic device, which serves here as a demonstrator, incorporates a uniform porous structure and was manufactured using a picosecond pulsed laser. The sensors were attached to the inlet and outlet channels of the microfluidic pattern to perform simple experiments, the aim of which was to evaluate the performance of both the connectors and the sensors in a practical microfluidic environment. The bespoke connectors ensured robust and watertight connection, allowing the sensors to be safely disconnected if necessary, without damaging the microfluidic device. The pH SensorPlugs were tested with a pH 7.01 buffer solution. They measured the correct pH values with an accuracy of ±0.05 pH once sufficient contact between the injected fluid and the measuring element (optode) was established. In turn, the FOP-MIV sensors were used to measure local pressure in the inlet and outlet channels during injection and the steady flow of deionized water at different rates. These sensors were calibrated up to 140 mbar and provided pressure measurements with an uncertainty that was less than ±1.5 mbar. Readouts at a rate of 4 Hz allowed us to observe dynamic pressure changes in the device during the displacement of air by water. In the case of steady flow of water, the pressure difference between the two measuring points increased linearly with increasing flow rate, complying with Darcy’s law for incompressible fluids. These data can be used to determine the permeability of the porous structure within the device.

scholarly journals Self-Aligned Interdigitated Transducers for Acoustofluidics

2016 ◽  
Author(s):  
Zhichao Ma ◽  
Adrian J. T. Teo ◽  
Say Hwa Tan ◽  
Ye Ai ◽  
Nam-Trung Nguyen
Keyword(s):  
Acoustic Wave ◽  
Surface Acoustic Wave ◽  
Particle Separation ◽  
Microfluidic Devices ◽  
Current Approach ◽  
Droplet Generation ◽  
Microfluidic Channels ◽  
Clean Room ◽  
Precise Location ◽  
Innovative Method

Surface acoustic wave (SAW) is effective for the manipulation of fluids and particles in microscale. The current approach of integrating interdigitated transducers (IDTs) for SAW generation into microfluidic channels involves complex and laborious microfabrication steps. These steps often require the full access to clean room facilities and hours to align the transducers to the precise location. This work presents an affordable and innovative method for fabricating SAW-based microfluidic devices without the need of clean room facilities and alignment. The IDTs and microfluidic channels are fabricated in the same process and thus precisely self-aligned in accordance with the device design. With the use of the developed fabrication approach, a few types of different SAW-based microfluidic devices have been fabricated and demonstrated for particle separation and active droplet generation.

A Multifunctional Microfluidic Device Based on Bifurcation Geometry

2010 ◽  
Author(s):  
Ahmed Fadl ◽  
Stefanie Demming ◽  
Zongqin Zhang ◽  
Bjo¨rn Hoxhold ◽  
Stephanus Bu¨ttgenbach ◽  
...  
Keyword(s):  
Microfluidic Device ◽  
Microfluidic Devices ◽  
Optical Lithography ◽  
Working Fluid ◽  
The Novel ◽  
Flow Rates ◽  
Single Function ◽  
Fluidic Device ◽  
Bifurcation Structures ◽  
Novel Design

Developing multifunctional devices are essential to realize more efficient Microsystems. With miniaturization processes taking place in many different applications, the rooms for single function microfluidic devices are limited. In this study, we introduce a multifunctional micro fluidic device based on bifurcation geometry which is capable of performing pumping and mixing at the same time. Optical lithography is used to fabricate the designed microfluidic device. The microfluidic device is tested at low actuator frequencies, and ethanol is employed as a working fluid. The operational principles are based on rectifying the oscillatory flows by using bifurcation structures for flow rectification. The results prove the feasibility of the novel design, and results are presented in terms of flow rates and maximum back pressures.

scholarly journals Fabrication of unconventional inertial microfluidic channels using wax 3D printing

Soft Matter ◽  
2020 ◽  
Vol 16 (10) ◽  
pp. 2448-2459 ◽  
Author(s):  
Mohammad Amin Raoufi ◽  
Sajad Razavi Bazaz ◽  
Hamid Niazmand ◽  
Omid Rouhi ◽  
Mohsen Asadnia ◽  
...  
Keyword(s):  
3D Printing ◽  
Microfluidic Devices ◽  
Microfluidic Channels ◽  
Printing Method

A novel workflow for the fabrication of inertial microfluidic devices based on the wax 3D printing method.

Conductive single nanowires formed and analysed on microfluidic devices

2016 ◽  
Vol 4 (39) ◽  
pp. 9235-9244 ◽  
Author(s):  
Yanlong Xing ◽  
Norbert Esser ◽  
Petra S. Dittrich
Keyword(s):  
Optical Properties ◽  
Microfluidic Device ◽  
Microfluidic Devices ◽  
Metal Salts ◽  
Reaction Flask ◽  
Electrical Conductivities ◽  
Single Nanowires ◽  
Derivatives Of

In this work, we studied the formation of fibres and particles made of metal salts and derivatives of tetrathiafulvalene (TTF) on a microfluidic device and in a conventional reaction flask, and characterized their morphologies, optical properties and electrical conductivities.

Diffusion Modeling in a Microchannel for Separation of Species

2004 ◽  
Author(s):  
P. K. Rajesh ◽  
P. Ponnambalam ◽  
N. Ramakrishnan ◽  
K. Prakasan
Keyword(s):  
Diffusion Process ◽  
Small Molecules ◽  
Microfluidic Device ◽  
Diffusion Rate ◽  
Microfluidic Channels ◽  
Diffusion Modeling ◽  
Large Molecules ◽  
Sample Stream ◽  
Large Particles ◽  
Optimization Of Geometry

Recently there is an increased interest in the design of microfluidic devices for research in biotechnological studies, applied to sample detection and analysis of species. When fluids are confined to small volumes, mixing results almost entirely by diffusion due to low velocities of flow in microchannels. As a result, it is possible to design microfluidic systems in which dissimilar fluids flow along side each other over long distances without significant mixing. The H-filter is a microfluidic device used for the extraction of molecular analytes from liquids containing interfering particles. The principle behind H filter is that small molecules will diffuse quickly from a sample stream to the buffer stream while very large molecules and particles will remain indefinitely in the sample stream because of their much larger size and much decreased diffusion rate. Because the Reynolds number in most microfluidic channels is generally kept well below 1, no turbulent mixing of fluids occurs. The only means by which solvents, solutes and suspended particles move in a direction transverse to the direction of flow is by diffusion. Differences in diffusion coefficients can be used to separate molecules of large particles over time. The time spent in flowing in a channel is proportional to the length of the channel. Before carrying out experiments, it is worthwhile to simulate the diffusion process in a microfluidic device for various properties of species and channel geometry. This paper attempts to model the diffusion process in an H-filter for typical species using CFD-ACE+, a software for solving problems in fluid dynamics with multi-physics capabilities. A module of CFD ACE+, called user-scalar that allows the user to define scalar quantities and boundary conditions for this scalar is used in the simulation. As seen from the studies, the diffusivities of species A and B in the buffer influence their diffusion. Optimization of geometry for a given species can be done with this method and separation can be achieved. The results from such a study will be useful for the design optimization and fabrication of such devices.

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