scholarly journals Rapid Microfluidic Mixer Based on Ferrofluid and Integrated Microscale NdFeB-PDMS Magnet

Micromachines ◽  
2019 ◽  
Vol 11 (1) ◽  
pp. 29
Author(s):  
Ran Zhou ◽  
Athira N. Surendran ◽  
Marcel Mejulu ◽  
Yang Lin

Ferrofluid-based micromixers have been widely used for a myriad of microfluidic industrial applications in biochemical engineering, food processing, and detection/analytical processes. However, complete mixing in micromixers is extremely time-consuming and requires very long microchannels due to laminar flow. In this paper, we developed an effective and low-cost microfluidic device integrated with microscale magnets manufactured with neodymium (NdFeB) powders and polydimethylsiloxane (PDMS) to achieve rapid micromixing between ferrofluid and buffer flow. Experiments were conducted systematically to investigate the effect of flow rate, concentration of the ferrofluid, and micromagnet NdFeB:PDMS mass ratio on the mixing performance. It was found that mixing is more efficient with lower total flow rates and higher ferrofluid concentration, which generate greater magnetic forces acting on both streamwise and lateral directions to increase the intermixing of the fluids within a longer residence time. Numerical models were also developed to simulate the mixing process in the microchannel under the same conditions and the simulation results indicated excellent agreements with the experimental data on mixing performance. Combining experimental measurements and numerical simulations, this study demonstrates a simple yet effective method to realize rapid mixing for lab-on-chip systems.

Micromachines ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1467
Author(s):  
Harry Dawson ◽  
Jinane Elias ◽  
Pascal Etienne ◽  
Sylvie Calas-Etienne

The integration of optical circuits with microfluidic lab-on-chip (LoC) devices has resulted in a new era of potential in terms of both sample manipulation and detection at the micro-scale. On-chip optical components increase both control and analytical capabilities while reducing reliance on expensive laboratory photonic equipment that has limited microfluidic development. Notably, in-situ LoC devices for bio-chemical applications such as diagnostics and environmental monitoring could provide great value as low-cost, portable and highly sensitive systems. Multiple challenges remain however due to the complexity involved with combining photonics with micro-fabricated systems. Here, we aim to highlight the progress that optical on-chip systems have made in recent years regarding the main LoC applications: (1) sample manipulation and (2) detection. At the same time, we aim to address the constraints that limit industrial scaling of this technology. Through evaluating various fabrication methods, material choices and novel approaches of optic and fluidic integration, we aim to illustrate how optic-enabled LoC approaches are providing new possibilities for both sample analysis and manipulation.


2007 ◽  
Author(s):  
Andrew L. Clow ◽  
Rainer Künnemeyer ◽  
Paul Gaynor ◽  
John C. Sharpe

2008 ◽  
Vol 94 (2) ◽  
pp. 216-225 ◽  
Author(s):  
Marco Bianchessi ◽  
Sarah Burgarella ◽  
Marco Cereda

The development of new powerful applications and the improvement in fabrication techniques are promising an explosive growth in lab-on-chip use in the upcoming future. As the demand reaches significant levels, the semiconductor industry may enter in the field, bringing its capability to produce complex devices in large volumes, high quality and low cost. The lab-on-chip concept, when applied to medicine, leads to the point-of-care concept, where simple, compact and cheap instruments allow diagnostic assays to be performed quickly by untrained personnel directly at the patient's side. In this paper, some practical and economical considerations are made to support the advantages of point-of-care testing. A series of promising technologies developed by STMicroelectronics on lab-on-chips is also presented, mature enough to enter in the common medical practice. The possible use of these techniques for cancer research, diagnosis and treatment are illustrated together with the benefits offered by their implementation in point-of-care testing.


Lab on a Chip ◽  
2012 ◽  
Vol 12 (22) ◽  
pp. 4738 ◽  
Author(s):  
Mohamed Lemine Youba Diakité ◽  
Jerôme Champ ◽  
Stephanie Descroix ◽  
Laurent Malaquin ◽  
François Amblard ◽  
...  

IEEE Access ◽  
2020 ◽  
Vol 8 ◽  
pp. 70733-70745
Author(s):  
Yumin Liao ◽  
Ningmei Yu ◽  
Dian Tian ◽  
Chen Wang ◽  
Shuaijun Li ◽  
...  

Author(s):  
Wei Xu ◽  
Hong Xue ◽  
Mark Bachman ◽  
G. P. Li

Microflow valving and regulating are two important functions for microfluidic systems for applications such as Lab-on-Chip. Although silicon based counterparts have been studied extensively, few good technologies exist for polymer based microvalves and regulators. In this paper, we present designs and methods for microvalve and microflow regulators that are readily integrated into polymer microfluidic devices. The technologies utilize “air-pocket” structures built into the sidewalls of the microchannels. When liquid is filled in such a channel, air is trapped in “air pocket” structures due to the hydrophobicity of the polymer. By creating a small thermal gradient between the fluid in the channel and the air in the pockets, one can controllably evaporate fluid into the air pocket where it condenses. This displaces air out of the pocket into the flow channel, increasing the resistance to flow. The air valve retreats to its original pocket when the temperature gradient is removed, thus allowing one to increase or decrease fluid flow at will. If the temperature gradient is maintained long enough, the air will completely block the channel, forming an irreversible valving of the flow. Therefore, the same device can be used as either a valve or flow-regulating device. Microfluidic prototypes were built and tested using this technology. The results show successful constant flow delivery as well as valve function. This novel vapor based microflow valve and regulator has advantages of low cost, simple design, and both ease of fabrication and integration.


2013 ◽  
Vol 448-453 ◽  
pp. 396-401
Author(s):  
Nuno Miguel Matos Pires ◽  
Tao Dong

Routine analysis of steroid hormones in environmental water samples demands for cost-effective tools that can detect multiple targets simultaneously. This study reports a high-throughput polymer platform integrated to polymer optical sensors for on-site monitoring of hormones in water. This opto-microfluidic device concept is fully compatible to low-cost fabrication methods. A competitive chemiluminescence immunoassay was performed onto gold thin film coated chambers, and a detection resolution of roughly 0.2 ng/mL was obtained using 17β-estradiol as the model target. Furthermore, the integrated polymer platform showed good recovery for the estradiol target when spiked in surface water samples.


2013 ◽  
Vol 22 (02) ◽  
pp. 1250081 ◽  
Author(s):  
FAISAL T. ABU-NIMEH ◽  
FATHI M. SALEM

We present a low-cost, low-power, high efficiency, and portable integrated implementations of a lab-on-chip for magnetic molecular level sensing manipulation, and diagnosis. The design features an all-integrated programmable magnetic coil array for sensing and actuating small magnetic bead objects. The coil array is selectively and dynamically controlled using the smallest permissible vertical coil inductors in this technology. Each cell, composed of the coil and its logical control circuitry, can detect small objects in the order of 1 μm diameter as well as emit eight programmable magnetic field levels for manipulation. All array sensing and driving components are shared to reduce the overall imprint. They are tuned towards the 900 s MHz ISM band and incorporating high-speed serial row/column switching up to 40 MHz for seamless pseudo-parallel operation.


Sensors ◽  
2021 ◽  
Vol 21 (17) ◽  
pp. 5816
Author(s):  
Piotr Słobodzian ◽  
Krzysztof Szostak ◽  
Katarzyna Skowronek ◽  
Laura Jasińska ◽  
Karol Malecha

In this paper, we describe a low-cost microwave microfluidic system of ultrahigh sensitivity for detecting small changes in the concentration of polar solutions (liquid dielectrics) in the 2.4 GHz ISM band. Its principle of operation is based on microwave interferometry, which is implemented using planar microstrip lines and integrated microwave components. The key features of this system include small solution intake (<200 µL per measurement), short time of measurement (ca. 20 ms), ultrahigh sensitivity of concentration changes (up to 55 dB/%), and low error of measurement (below 0.1%). The ultrahigh sensitivity was proven experimentally by measurements of the fat content of milk. In addition, it is a user-friendly system due to an effortless and fast calibration procedure. Moreover, it can be made relatively compact (<20 cm2) and features low power consumption (200 mW). Thus, the proposed system is perfect for industrial applications, especially for highly integrated lab-on-chip devices.


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