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

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.

2021 ◽  
Vol 4 (1) ◽  
pp. 48
Author(s):  
Jacob L. Binsley ◽  
Elizabeth L. Martin ◽  
Thomas O. Myers ◽  
Stefano Pagliara ◽  
Feodor Y. Ogrin

Many lab-on-a-chip devices require a connection to an external pumping system in order to perform their function. While this is not problematic in typical laboratory environments, it is not always practical when applied to point-of-care testing, which is best utilized outside of the laboratory. Therefore, there has been a large amount of ongoing research into producing integrated microfluidic components capable of generating effective fluid flow from on-board the device. This research aims to introduce a system that can produce practical flow rates, and be easily fabricated and actuated using readily available techniques and materials. We show how an asymmetric elasto-magnetic system, inspired by Purcell’s three-link swimmer, can provide this solution through the generation of non-reciprocal motion in an enclosed environment. The device is fabricated monolithically within a microfluidic channel at the time of manufacture, and is actuated using a weak, oscillating magnetic field. The flow rate can be altered dynamically, and the direction of the resultant flow can be controlled by adjusting the frequency of the driving field. The device has been proven, experimentally and numerically, to operate effectively when applied to fluids with a range of viscosities. Such a device may be able to replace external pumping systems in portable applications.


Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1366
Author(s):  
Jaehoon Kim ◽  
Junghyo Yoon ◽  
Jae-Yeong Byun ◽  
Hyunho Kim ◽  
Sewoon Han ◽  
...  

Blood plasma is a source of biomarkers in blood and a simple, fast, and easy extraction method is highly required for point-of-care testing (POCT) applications. This paper proposes a membrane filter integrated microfluidic device to extract blood plasma from whole blood, without any external instrumentation. A commercially available membrane filter was integrated with a newly designed dual-cover microfluidic device to avoid leakage of the extracted plasma and remaining blood cells. Nano-interstices installed on both sides of the microfluidic channels actively draw the extracted plasma from the membrane. The developed device successfully supplied 20 μL of extracted plasma with a high extraction yield (~45%) in 16 min.


Nanomedicine ◽  
2021 ◽  
Author(s):  
Smriti Sharma ◽  
Vinayak Bhatia

The use of magnetic nanoparticles (MNPs) in microfluidics based diagnostics is a classic case of micro-, nano- and bio-technology coming together to design extremely controllable, reproducible, and scalable nano and micro ‘ on-chip bio sensing systems.’ In this review, applications of MNPs in microfluidics ranging from molecular diagnostics and immunodiagnostics to clinical uses have been examined. In addition, microfluidic mixing and capture of analytes using MNPs, and MNPs as carriers in microfluidic devices has been investigated. Finally, the challenges and future directions of this upcoming field have been summarized. The use of MNP-based microfluidic devices, will help in developing decentralized or ‘ point of care’ testing globally, contributing to affordable healthcare, particularly, for middle- and low-income developing countries.


Sensors ◽  
2018 ◽  
Vol 18 (12) ◽  
pp. 4124 ◽  
Author(s):  
Fabiana Felix ◽  
Alexandre Baccaro ◽  
Lúcio Angnes

Disposable immunosensors are analytical devices used for the quantification of a broad variety of analytes in different areas such as clinical, environmental, agricultural and food quality management. They detect the analytes by means of the strong interactions between antibodies and antigens, which provide concentration-dependent signals. For the herein highlighted voltammetric immunosensors, the analytical measurements are due to changes in the electrical signals on the surface of the transducers. The possibility of using disposable and miniaturized immunoassays is a very interesting alternative for voltammetric analyses, mainly, when associated with screen-printing technologies (screen-printed electrodes, SPEs), and microfluidic platforms. The aim of this paper is to discuss a carefully selected literature about different examples of SPEs-based immunosensors associated with microfluidic technologies for diseases, food, agricultural and environmental analysis. Technological aspects of the development of the voltammetric immunoassays such as the signal amplification, construction of paper-based microfluidic platforms and the utilization of microfluidic devices for point-of-care testing will be presented as well.


Lab on a Chip ◽  
2019 ◽  
Vol 19 (4) ◽  
pp. 574-579 ◽  
Author(s):  
M. Adiraj Iyer ◽  
D. T. Eddington

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.


Sensors ◽  
2020 ◽  
Vol 20 (22) ◽  
pp. 6609
Author(s):  
Simone Cavalera ◽  
Fabio Di Nardo ◽  
Luca Forte ◽  
Francesca Marinoni ◽  
Matteo Chiarello ◽  
...  

Multiplex lateral flow immunoassay (LFIA) is largely used for point-of-care testing to detect different pathogens or biomarkers in a single device. The increasing demand for multitargeting diagnostics requires multi-informative single tests. In this study, we demonstrated three strategies to upgrade standard multiplex LFIA to multimodal capacity. As a proof-of-concept, we applied the strategies to the differential diagnosis of Human Immunodeficiency Virus (HIV) infection, a widespread pathogen, for which conventional multiplex LFIA testing is well-established. In the new two-parameter LFIA (x2LFIA), we exploited color encoding, in which the binding of multiple targets occurs in one reactive band and the color of the probe reveals which one is present in the sample. By combining the sequential alignment of several reactive zones along the membrane of the LFIA strip and gold nanoparticles and gold nanostars for the differential visualization, in this demonstration, the x2LFIA can furnish information on HIV serotype and stage of infection in a single device. Three immunosensors were designed. The use of bioreagents as the capturing ligand anchored onto the membrane or as the detection ligand labelled with gold nanomaterials affected the performance of the x2LFIA. Higher detectability was achieved by the format involving the HIV-specific antigens as capturing agent and labelled secondary bioligands (anti-human immunoglobulins M and protein G) as the probes.


Lab on a Chip ◽  
2020 ◽  
Vol 20 (22) ◽  
pp. 4285-4295
Author(s):  
Jacob L. Binsley ◽  
Elizabeth L. Martin ◽  
Thomas O. Myers ◽  
Stefano Pagliara ◽  
Feodor Y. Ogrin

Integrated elasto-magnetic pumps power portable microfluidic devices for point of care testing.


2020 ◽  
Vol 11 ◽  
pp. 117959722094143
Author(s):  
Dilshan Sooriyaarachchi ◽  
Shahrima Maharubin ◽  
George Z Tan

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.


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