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 Electrowetting on Dielectric (EWOD) Device with Dimple Structures for Highly Accurate Droplet Manipulation

2019 ◽  
Vol 9 (12) ◽  
pp. 2406 ◽  
Author(s):  
Katsuo Mogi ◽  
Shungo Adachi ◽  
Naoki Takada ◽  
Tomoya Inoue ◽  
Tohru Natsume
Keyword(s):  
High Speed ◽  
Thin Sheet ◽  
Digital Microfluidics ◽  
Three Dimensional ◽  
Substrate Type ◽  
Droplet Motion ◽  
Electrowetting On Dielectric ◽  
Flat Substrate ◽  
Single Substrate ◽  
Droplet Manipulation

Digital microfluidics based on electrowetting on dielectric (EWOD) devices has potential as a fundamental technology for the accurate preparation of dangerous reagents, the high-speed dispensing of rapidly deteriorating reagents, and the fine adjustment of expensive reagents, such as the preparation of for positron emission tomography (PET). To allow single substrate type EWODs to be practically used in an automatic operation system, we developed a dimple structure as a key technique for a highly accurate droplet manipulation method. The three-dimensional shape of the dimple structure is embossed onto a disposable thin sheet. In this study, we confirmed that the dimple structure can suppress unintended droplet motion caused by unidentified factors. In addition, the stability of the droplets on the dimple structures was evaluated using a sliding experiment. On a flat substrate, the success rate of a droplet motion was lower than 70.8%, but on the dimple structure, the droplets were able to be moved along the dimple structures correctly without unintended motion caused by several environmental conditions. These results indicated that the dimple structure increased the controllability of the droplets. Hence, the dimple structure will contribute to the practical application of digital microfluidics based on single substrate type EWODs.

A Robust Superhydrophobic Surface for Digital Microfluidics

2011 ◽  
Author(s):  
David Barona ◽  
A. Amirfazli
Keyword(s):  
Superhydrophobic Surface ◽  
Mechanical Stability ◽  
Contact Angle Hysteresis ◽  
Digital Microfluidics ◽  
Microfluidic Devices ◽  
Contact Angles ◽  
Lab On Chip ◽  
Adverse Conditions ◽  
On Chip ◽  
Digital Microfluidic

Digital microfluidics depends on efficient movement of individual drops for a variety of tasks, e.g. reagent delivery, mixing, sampling, etc. Superhydrophobic (SH) coatings generally show high repellency and low adhesion for a variety of liquids. Therefore, SH coatings can provide for an efficient drop delivery and hence low energy requirements for a fluidic chip. However, wide application of such coatings is hampered by fragile nature of such coatings to date. A new SH coating is developed that addresses the fragility challenge of such coatings. It is based on application of nanoparticles to fluoropolymers. The mechanical stability, wear resistance and durability under prolonged liquid exposure of this new coating is discussed. It is shown that the new SH coating can maintain high contact angles, low contact angle hysteresis needed for drop mobility under adverse conditions/application of digital microfluidic devices. The developed SH coating can also be sprayed onto various surfaces, including glass used in traditional lab-on-chip (LOC) devices, or even paper for enabling novel Lap-on-paper (LOP) devices.

scholarly journals A Low-Cost, Disposable and Portable Inkjet-Printed Biochip for the Developing World

Sensors ◽  
2020 ◽  
Vol 20 (12) ◽  
pp. 3593
Author(s):  
Kushal Joshi ◽  
Vanessa Velasco ◽  
Rahim Esfandyarpour
Keyword(s):  
Low Income ◽  
Capital Investment ◽  
Point Of Care ◽  
Low Cost ◽  
Low Income Countries ◽  
Electrode Arrays ◽  
Electrowetting On Dielectric ◽  
Biochemical Assays ◽  
Fabrication Procedure ◽  
Digital Microfluidic

Electrowetting on dielectric-based digital microfluidic platforms (EWOD-DMF) have a potential to impact point-of-care diagnostics. Conventionally, EWOD-DMF platforms are manufactured in cleanrooms by expert technicians using costly and time consuming micro-nanofabrication processes such as optical lithography, depositions and etching. However, such high-end microfabrication facilities are extremely challenging to establish in resource-poor and low-income countries, due to their high capital investment and operating costs. This makes the fabrication of EWOD-DMF platforms extremely challenging in low-income countries, where such platforms are most needed for many applications such as point-of-care testing applications. To address this challenge, we present a low-cost and simple fabrication procedure for EWOD-DMF electrode arrays, which can be performed anywhere with a commercial office inkjet printer without the need of expensive cleanroom facilities. We demonstrate the utility of our platform to move and mix droplets of different reagents and physiologically conductive buffers, thereby showing its capability to potentially perform a variety of biochemical assays. By combining our low-cost, inkjet-printed EWOD-DMF platform with smartphone imaging technology and a compact control system for droplet manipulation, we also demonstrate a portable and hand-held device which can be programmed to potentially perform a variety of biochemical assays.

Magnetic Digital Microfluidics for Point-of-Care Testing: Where Are We Now?

2020 ◽  
Vol 27 ◽  
Author(s):  
Yi Zhang
Keyword(s):  
System Integration ◽  
Diagnostic Tests ◽  
Point Of Care ◽  
Digital Microfluidics ◽  
Controlled Environment ◽  
Point Of Care Testing ◽  
Microfluidic Platforms ◽  
Interface System ◽  
Technical Issues ◽  
Sample System

: Point-of-care (POC) testing decentralizes the diagnostic tests to the sites near the patient. Many POC tests rely microfluidic platforms for sample-to-answer analysis. Compared to other microfluidic systems, magnetic digital microfluidics demonstrate compelling advantages for POC diagnostics. In this review, we have examined the capability of magnetic digital microfluidics-based POC diagnostic platforms. More importantly, we have categorized POC settings into three classes based on “where is the point”, “who to care” and “how to test”, and evaluated the suitability of magnetic digital microfluidics in various POC settings. Furthermore, we have addressed other technical issues associated with POC testing such as controlled environment, sample-system interface, system integration and information connectivity. We hope this review would provide a guideline for the future development of magnetic digital microfluidics-based platforms for POC testing.

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 Label-free DNA biosensing by topological light confinement

Nanophotonics ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Gianluigi Zito ◽  
Gennaro Sanità ◽  
Bryan Guilcapi Alulema ◽  
Sofía N. Lara Yépez ◽  
Vittorino Lanzio ◽  
...  
Keyword(s):  
Single Molecule ◽  
Bound States ◽  
Production Control ◽  
Point Of Care ◽  
Low Cost ◽  
Label Free ◽  
Large Area ◽  
Light Confinement ◽  
Binding Event ◽  
The Continuum

Abstract Large-area and transparent all-dielectric metasurfaces sustaining photonic bound states in the continuum (BICs) provide a set of fundamental advantages for ultrasensitive biosensing. BICs bridge the gap of large effective mode volume with large experimental quality factor. Relying on the transduction mechanism of reactive sensing principle, herein, we first numerically study the potential of subwavelength confinement driven by topological decoupling from free space radiation for BIC-based biosensing. Then, we experimentally combine this capability with minimal and low-cost optical setup, applying the devised quasi-BIC resonator for PNA/DNA selective biosensing with real-time monitoring of the binding event. A sensitivity of 20 molecules per micron squared is achieved, i.e. ≃0.01 pg. Further enhancement can easily be envisaged, pointing out the possibility of single-molecule regime. This work aims at a precise and ultrasensitive approach for developing low-cost point-of-care tools suitable for routine disease prescreening analyses in laboratory, also adaptable to industrial production control.

scholarly journals Development of Epoxy Resin-Based Elastomeric Microfluidic Devices Using CO2 Laser Ablation for DNA-Amplification Point-Of-Care (POC) Applications: Assessment of Microchannels' Dimensions and Quality

2021 ◽  
Author(s):  
Heba Mansour ◽  
Ahmed M.R. Fath El-Bab ◽  
Emad A. Soliman ◽  
Ahmed L. Abdel-Mawgood
Keyword(s):  
Laser Ablation ◽  
Epoxy Resin ◽  
Epoxy Resins ◽  
Carbon Dioxide Laser ◽  
Microfluidic Devices ◽  
Microfluidic Chips ◽  
Laser Technique ◽  
Lab On Chip ◽  
Expensive Equipment ◽  
The Impact

Abstract Microfluidic devices are a rising technology to automatize chemical and biological operations. In this context, laser ablation has significant potential for polymer-based microfluidic platforms' fast and economical manufacturing. Nevertheless, the manufacturing of epoxy-based microfluidic chips is considered highly cost full due to demand for cleanroom facilities that utilize expensive equipment and lengthy processes. Therefore, this study targeted investigating the feasibility of epoxy resins to be fabricated as a lab-on-chip using carbon dioxide laser ablation. The chemical structural properties and thermal stability of the plain epoxy resins were characterized by Fourier transform infrared spectral analysis (FT-IR) and thermogravimetric analysis (TGA). Moreover, a specific migration test was performed to quantify potential migrants by gas chromatography coupled to mass spectrometry (GC-MS) to prove that the cured epoxy resin would not release unreacted monomers to the biological solution test, which caused inhibition of the sensitive biological reactions. By investigating the impact of this process on microchannels' dimensions and quality, a laser technique using CO2 laser was used in vector mode to engrave into a transparent epoxy resin chip. The resulting microchannels were characterized using 3D Laser microscopy. The outcomes of this study showed considerable potential for laser ablation in machining the epoxy-based chips, whereas the microchannels were produced with minor bulges' height (0.027 µm) with no clogging. Moreover, a reasonable depth of 99.31 µm with roughness (Ra) of 14.52 µm was obtained at a laser speed of 5 mm/s and laser power of 1.8 W. This process can produce epoxy resin-based microfluidic chips without the need for cleanroom facilities that require expensive equipment and lengthy process.

Large-Area Fabrication of Superhydrophobic Micro-Conical Pillar Arrays on Various Metallic Substrates

Nanoscale ◽  
2021 ◽  
Author(s):  
Weihao Pan ◽  
Song Wu ◽  
Liu Huang ◽  
Jinlong Song
Keyword(s):  
Corrosion Resistance ◽  
Water Droplet ◽  
Large Area ◽  
Water Separation ◽  
Metallic Substrates ◽  
Pillar Arrays ◽  
Oil Water Separation ◽  
Oil Water ◽  
Droplet Manipulation ◽  
Application Prospects

Superhydrophobic micro-conical pillar arrays have huge application prospects, from anti-icing to oil/water separation, corrosion resistance, and water droplet manipulation. However, there is still a lack of versatile methods with high...

Numerical Simulation of Digital Microfluidics Based on Electro-Dynamic Model

2012 ◽  
Vol 2 (3) ◽  
pp. 14-23
Author(s):  
Liguo Chen ◽  
Mingxiang Ling ◽  
Deli Liu
Keyword(s):  
Numerical Simulation ◽  
Simulation Model ◽  
Contact Line ◽  
Contact Area ◽  
Digital Microfluidics ◽  
Phase Contact ◽  
Electrowetting On Dielectric ◽  
Three Phase ◽  
Internal Mechanism ◽  
Contact Domain

Aiming at the doubt and divarication about the internal mechanism of electrowetting on dielectric (EWOD) in digital microfluidics, the authors attempted to explain the internal mechanism of EWOD through electro-dynamic-based numerical simulation model. First, the boundary conditions for the governing equation were found. Then the influence of mesh number on simulation results was analyzed and feasibility of the simulation model was verified by comparing numerical results with theoretical ratiocination. Finally, they compared the electro-dynamic actuation force acting on the surface of droplet on three digital microfluidic structures, which have the same three-phase contact line but different area of contact domain. Analytical results showed that electro-dynamic force generated solely by the accumulation of induced charges in contact domain was three times larger than that generated by three-phase contact line. Induced charges accumulated on both three-phase contact line and contact area of droplet gave the contribution to EWOD, but contact area played a major role in the change of contact angle of droplet.

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