scholarly journals Wax-Printed Fluidic Time Delays for Automating Multi-Step Assays in Paper-Based Microfluidic Devices (MicroPADs)

Inventions ◽  
2019 ◽  
Vol 4 (1) ◽  
pp. 20 ◽  
Author(s):  
E. Strong ◽  
Carsten Knutsen ◽  
Jay Wells ◽  
Aditya Jangid ◽  
Megan Mitchell ◽  
...  
Keyword(s):  
Time Delays ◽  
Point Of Care ◽  
Microfluidic Devices ◽  
Fabrication Technique ◽  
Enzymatic Assays ◽  
Real World Applications ◽  
Test Zone ◽  
Fluid Control ◽  
Long Channel ◽  
Ideal Method

Microfluidic paper-based analytical devices (microPADs) have emerged as a promising platform for point-of-care diagnostic devices. While the inherent wicking properties of microPADs allow for fluid flow without supporting equipment, this also presents a major challenge in achieving robust fluid control, which becomes especially important when performing complex multi-step assays. Herein, we describe an ideal method of fluid control mediated by wax-printed fluidic time delays. This method relies on a simple fabrication technique, does not utilize chemicals/reagents that could affect downstream assays, is readily scalable, and has a wide temporal range of tunable fluid control. The delays are wax printed on both the top and bottom of pre-fabricated microPAD channels, without subsequent heating, to create hemi-/fully-enclosed channels. With these wax printed delays, we were able to tune the time it took aqueous solutions to wick across a 25 mm-long channel between 3.6 min and 13.4 min. We then employed these fluid delays in the sequential delivery of four dyes to a test zone. Additionally, we demonstrated the automation of two simple enzymatic assays with this fluid control modality. This method of fluid control may allow future researchers to automate more complex assays, thereby further advancing microPADs toward real-world applications.

scholarly journals Disposable Voltammetric Immunosensors Integrated with Microfluidic Platforms for Biomedical, Agricultural and Food Analyses: A Review

Sensors ◽  
2018 ◽  
Vol 18 (12) ◽  
pp. 4124 ◽  
Author(s):  
Fabiana Felix ◽  
Alexandre Baccaro ◽  
Lúcio Angnes
Keyword(s):  
Quality Management ◽  
Signal Amplification ◽  
Screen Printing ◽  
Point Of Care ◽  
Microfluidic Devices ◽  
Strong Interactions ◽  
Point Of Care Testing ◽  
Microfluidic Platforms ◽  
Broad Variety ◽  
Interesting Alternative

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.

scholarly journals Programmable Paper-Based Microfluidic Devices for Biomarker Detections

Micromachines ◽  
2019 ◽  
Vol 10 (8) ◽  
pp. 516 ◽  
Author(s):  
Veasna Soum ◽  
Sooyong Park ◽  
Albertus Ivan Brilian ◽  
Oh-Sun Kwon ◽  
Kwanwoo Shin
Keyword(s):  
Point Of Care ◽  
High Sensitivity ◽  
Microfluidic Devices ◽  
Portable Devices ◽  
Biomarker Detection ◽  
Fluid Delivery ◽  
Wide Range ◽  
Paper Based Microfluidics ◽  
Digital Microfluidic ◽  
Detection Of Biomarkers

Recent advanced paper-based microfluidic devices provide an alternative technology for the detection of biomarkers by using affordable and portable devices for point-of-care testing (POCT). Programmable paper-based microfluidic devices enable a wide range of biomarker detection with high sensitivity and automation for single- and multi-step assays because they provide better control for manipulating fluid samples. In this review, we examine the advances in programmable microfluidics, i.e., paper-based continuous-flow microfluidic (p-CMF) devices and paper-based digital microfluidic (p-DMF) devices, for biomarker detection. First, we discuss the methods used to fabricate these two types of paper-based microfluidic devices and the strategies for programming fluid delivery and for droplet manipulation. Next, we discuss the use of these programmable paper-based devices for the single- and multi-step detection of biomarkers. Finally, we present the current limitations of paper-based microfluidics for biomarker detection and the outlook for their development.

Point-of-care biochemical assays using gold nanoparticle-implemented microfluidics

2014 ◽  
Vol 43 (17) ◽  
pp. 6239-6253 ◽  
Author(s):  
Jiashu Sun ◽  
Yunlei Xianyu ◽  
Xingyu Jiang
Keyword(s):  
Gold Nanoparticles ◽  
Gold Nanoparticle ◽  
Point Of Care ◽  
Microfluidic Devices ◽  
Biochemical Assays

This review focuses on assaying biomarkers using both gold nanoparticles and microfluidic devices.

scholarly journals Scaling Electrowetting with Printed Circuit Boards for Large Area Droplet Manipulation

MRS Advances ◽  
2018 ◽  
Vol 3 (26) ◽  
pp. 1475-1483 ◽  
Author(s):  
Udayan Umapathi ◽  
Samantha Chin ◽  
Patrick Shin ◽  
Dimitris Koutentakis ◽  
Hiroshi Ishii
Keyword(s):  
Printed Circuit Boards ◽  
Dielectric Material ◽  
Point Of Care ◽  
Digital Microfluidics ◽  
Microfluidic Devices ◽  
Electrode Arrays ◽  
Large Area ◽  
Lab On Chip ◽  
Electrowetting On Dielectric ◽  
Droplet Manipulation

ABSTRACTDroplet based microfluidics (digital microfluidics) with Electrowetting on dielectric (EWOD) has gained popularity with the promise of being technology for a true lab-on-chip device with applications spanning across assays/library prep, next-gen sequencing and point-of-care diagnostics. Most electrowetting device architecture are linear electrode arrays with a shared path for droplets, imposing serious limitations -- cross contamination and limited number of parallel operations. Our work is in addressing these issues through large 2D grid arrays with direct addressability providing flexible programmability.Scaling electrowetting to larger arrays still remains a challenge due to complex and expensive cleanroom fabrication of microfluidic devices. We take the approach of using inexpensive PCB manufacturing, investigate challenges and solutions for scaling electrowetting to large area droplet manipulation. PCB manufactured electrowetting arrays impose many challenges due to the irregularities from process and materials used. These challenges generally relate to preparing the surface that interfaces with droplets -- a dielectric material on the electrodes and the top most hydrophobic coating that interfaces with the droplets. A requirement for robust droplet manipulation with EWOD is thin (<10um) hydrophobic dielectric material which does not break down at droplet actuation voltages (AC/DC, 60V to 200V) and has a no droplet pinning. For this, we engineered materials specifically for large area PCBs.Traditionally, digital microfluidic devices sandwich droplets between two plates and have focussed on sub-microliter droplet volumes. In our approach, droplets are on an open surface with which we are able to manipulate droplets in microliter and milliliter volumes. With milliliter droplet manipulation ability on our electrowetting device, we demonstrate “digital millifluidics”. Finally, we report the performance of our device and to motivate the need for large open arrays we show an example of running multiple parallel biological experiments.

scholarly journals Two Potential Clinical Applications of Origami-Based Paper Devices

Diagnostics ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 203
Author(s):  
Zong-Keng Kuo ◽  
Tsui-Hsuan Chang ◽  
Yu-Shin Chen ◽  
Chao-Min Cheng ◽  
Chia-Ying Tsai
Keyword(s):  
Limit Of Detection ◽  
Point Of Care ◽  
Test Sample ◽  
Clinical Applications ◽  
Ease Of Use ◽  
Enzyme Linked Immunosorbent Assay ◽  
Elisa System ◽  
Test Zone ◽  
Moist Environment ◽  
Simplex Virus

Detecting small amounts of analyte in clinical practice is challenging because of deficiencies in specimen sample availability and unsuitable sampling environments that prevent reliable sampling. Paper-based analytical devices (PADs) have successfully been used to detect ultralow amounts of analyte, and origami-based PADs (O-PADs) offer advantages that may boost the overall potential of PADs in general. In this study, we investigated two potential clinical applications for O-PADs. The first O-PAD we investigated was an origami-based enzyme-linked immunosorbent assay (ELISA) system designed to detect different concentrations of rabbit IgG. This device was designed with four wing structures, each of which acted as a reagent loading zone for pre-loading ELISA reagents, and a central test sample loading zone. Because this device has a low limit of detection (LOD), it may be suitable for detecting IgG levels in tears from patients with a suspected viral infection (such as herpes simplex virus (HSV)). The second O-PAD we investigated was designed to detect paraquat levels to determine potential poisoning. To use this device, we sequentially folded each of two separate reagent zones, one preloaded with NaOH and one preloaded with ascorbic acid (AA), over the central test zone, and added 8 µL of sample that then flowed through each reagent zone and onto the central test zone. The device was then unfolded to read the results on the test zone. The three folded layers of paper provided a moist environment not achievable with conventional paper-based ELISA. Both O-PADs were convenient to use because reagents were preloaded, and results could be observed and analyzed with image analysis software. O-PADs expand the testing capacity of simpler PADs while leveraging their characteristic advantages of convenience, cost, and ease of use, particularly for point-of-care diagnosis.

Electrokinetic Fluid Control in Two-Dimensional Planar Microfluidic Devices

2007 ◽  
Vol 79 (19) ◽  
pp. 7485-7491 ◽  
Author(s):  
Margaret A. Lerch ◽  
Stephen C. Jacobson
Keyword(s):  
Microfluidic Devices ◽  
Two Dimensional ◽  
Fluid Control

scholarly journals Negligible-cost microfluidic device fabrication using 3D-printed interconnecting channel scaffolds

PLoS ONE ◽  
2021 ◽  
Vol 16 (2) ◽  
pp. e0245206
Author(s):  
Harry Felton ◽  
Robert Hughes ◽  
Andrea Diaz-Gaxiola
Keyword(s):  
Rapid Prototyping ◽  
Point Of Care ◽  
Low Cost ◽  
Microfluidic Channel ◽  
Microfluidic Devices ◽  
Device Fabrication ◽  
Appropriate Technology ◽  
Channel Cross Section ◽  
Microfluidic Systems ◽  
3D Printed

This paper reports a novel, negligible-cost and open-source process for the rapid prototyping of complex microfluidic devices in polydimethylsiloxane (PDMS) using 3D-printed interconnecting microchannel scaffolds. These single-extrusion scaffolds are designed with interconnecting ends and used to quickly configure complex microfluidic systems before being embedded in PDMS to produce an imprint of the microfluidic configuration. The scaffolds are printed using common Material Extrusion (MEX) 3D printers and the limits, cost & reliability of the process are evaluated. The limits of standard MEX 3D-printing with off-the-shelf printer modifications is shown to achieve a minimum channel cross-section of 100×100 μm. The paper also lays out a protocol for the rapid fabrication of low-cost microfluidic channel moulds from the thermoplastic 3D-printed scaffolds, allowing the manufacture of customisable microfluidic systems without specialist equipment. The morphology of the resulting PDMS microchannels fabricated with the method are characterised and, when applied directly to glass, without plasma surface treatment, are shown to efficiently operate within the typical working pressures of commercial microfluidic devices. The technique is further validated through the demonstration of 2 common microfluidic devices; a fluid-mixer demonstrating the effective interconnecting scaffold design, and a microsphere droplet generator. The minimal cost of manufacture means that a 5000-piece physical library of mix-and-match channel scaffolds (100 μm scale) can be printed for ~$0.50 and made available to researchers and educators who lack access to appropriate technology. This simple yet innovative approach dramatically lowers the threshold for research and education into microfluidics and will make possible the rapid prototyping of point-of-care lab-on-a-chip diagnostic technology that is truly affordable the world over.

scholarly journals Elasto-Magnetic Pumps Integrated within Microfluidic Devices

2021 ◽  
Vol 4 (1) ◽  
pp. 48
Author(s):  
Jacob L. Binsley ◽  
Elizabeth L. Martin ◽  
Thomas O. Myers ◽  
Stefano Pagliara ◽  
Feodor Y. Ogrin
Keyword(s):  
Magnetic System ◽  
Point Of Care ◽  
Microfluidic Channel ◽  
Lab On A Chip ◽  
Microfluidic Devices ◽  
Point Of Care Testing ◽  
Ongoing Research ◽  
Flow Rates ◽  
Pumping System ◽  
Oscillating Magnetic Field

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.

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