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Zulkepli SNIS, Hamid NH, Shukla V. Droplet Velocity Measurement Based on Dielectric Layer Thickness Variation Using Digital Microfluidic Devices. Biosensors (Basel) 2018; 8:E45. [PMID: 29738428 PMCID: PMC6022883 DOI: 10.3390/bios8020045] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Revised: 03/22/2018] [Accepted: 03/22/2018] [Indexed: 11/16/2022]
Abstract
In recent years, the number of interdisciplinary research works related to the development of miniaturized systems with integrated chemical and biological analyses is increasing. Digital microfluidic biochips (DMFBs) are one kind of miniaturized systems designed for conducting inexpensive, fast, convenient and reliable biochemical assay procedures focusing on basic scientific research and medical diagnostics. The role of a dielectric layer in the digital microfluidic biochips is prominent as it helps in actuating microliter droplets based on the electrowetting-on-dielectric (EWOD) technique. The advantages of using three different material layers of dielectric such as parafilm, polytetrafluoroethylene (PTFE) and ethylene tetrafluoroethylene (ETFE) were reported in the current work. A simple fabrication process of a digital microfluidic device was performed and good results were obtained. The threshold of the actuation voltage was determined for all dielectric materials of varying thicknesses. Additionally, the OpenDrop device was tested by utilizing a single-plate system to transport microliter droplets for a bioassay operation. With the newly proposed fabrication methods, these dielectric materials showed changes in contact angle and droplet velocity when the actuation voltage was applied. The threshold actuation voltage for the dielectric layers of 10⁻13 μm was 190 V for the open plate DMFBs.
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Affiliation(s)
| | - Nor Hisham Hamid
- Department of Electrical and Electronic Engineering, Universiti Teknologi PETRONAS, Seri Iskander 32610, Malaysia.
| | - Vineeta Shukla
- Department of Electrical and Electronic Engineering, Universiti Teknologi PETRONAS, Seri Iskander 32610, Malaysia.
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Shekaramiz E, Varadarajalu G, Day PJ, Wickramasinghe HK. Integrated Electrowetting Nanoinjector for Single Cell Transfection. Sci Rep 2016; 6:29051. [PMID: 27374766 PMCID: PMC4931508 DOI: 10.1038/srep29051] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Accepted: 06/14/2016] [Indexed: 11/09/2022] Open
Abstract
Single cell transfection techniques are essential to understand the heterogeneity between cells. We have developed an integrated electrowetting nanoinjector (INENI) to transfect single cells. The high transfection efficiency, controlled dosage delivery and ease of INENI fabrication promote the widespread application of the INENI in cell transfection assays.
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Affiliation(s)
- Elaheh Shekaramiz
- Department of Biomedical Engineering, University of California Irvine, California, USA
| | | | - Philip J. Day
- Manchester Institute of Biotechnology, the University of Manchester, Manchester, UK
| | - H. Kumar Wickramasinghe
- Department of Biomedical Engineering, University of California Irvine, California, USA
- Department of Electrical Engineering, University of California Irvine, California, USA
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Huang HY, Shen HH, Tien CH, Li CJ, Fan SK, Liu CH, Hsu WS, Yao DJ. Digital Microfluidic Dynamic Culture of Mammalian Embryos on an Electrowetting on Dielectric (EWOD) Chip. PLoS One 2015; 10:e0124196. [PMID: 25933003 PMCID: PMC4416819 DOI: 10.1371/journal.pone.0124196] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2014] [Accepted: 02/26/2015] [Indexed: 01/04/2023] Open
Abstract
Current human fertilization in vitro (IVF) bypasses the female oviduct and manually inseminates, fertilizes and cultivates embryos in a static microdrop containing appropriate chemical compounds. A microfluidic microchannel system for IVF is considered to provide an improved in-vivo-mimicking environment to enhance the development in a culture system for an embryo before implantation. We demonstrate a novel digitalized microfluidic device powered with electrowetting on a dielectric (EWOD) to culture an embryo in vitro in a single droplet in a microfluidic environment to mimic the environment in vivo for development of the embryo and to culture the embryos with good development and live births. Our results show that the dynamic culture powered with EWOD can manipulate a single droplet containing one mouse embryo and culture to the blastocyst stage. The rate of embryo cleavage to a hatching blastocyst with a dynamic culture is significantly greater than that with a traditional static culture (p<0.05). The EWOD chip enhances the culture of mouse embryos in a dynamic environment. To test the reproductive outcome of the embryos collected from an EWOD chip as a culture system, we transferred embryos to pseudo-pregnant female mice and produced live births. These results demonstrate that an EWOD-based microfluidic device is capable of culturing mammalian embryos in a microfluidic biological manner, presaging future clinical application.
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Affiliation(s)
- Hong-Yuan Huang
- Department of Obstetrics and Gynecology, Linkou Medical Center, Chang Gung Memorial Hospital, Taoyuan, Taiwan
- Department of Obstetrics and Gynecology, Chang Gung University and College of Medicine, Taoyuan, Taiwan
| | - Hsien-Hua Shen
- Institute of Nanoengineering and Microsystem, National Tsing Hua University, Hsinchu, Taiwan
| | - Chang-Hung Tien
- Department of Mechanical Engineering, National Taiwan University, Taipei, Taiwan
| | - Chin-Jung Li
- Department of Obstetrics and Gynecology, Linkou Medical Center, Chang Gung Memorial Hospital, Taoyuan, Taiwan
| | - Shih-Kang Fan
- Department of Mechanical Engineering, National Taiwan University, Taipei, Taiwan
| | - Cheng-Hsien Liu
- Department of Power Mechanical Engineering, National Tsing Hua University, Hsinchu, Taiwan
| | - Wen-Syang Hsu
- Department of Mechanical Engineering, National Chiao Tung University, Hsinchu, Taiwan
| | - Da-Jeng Yao
- Institute of Nanoengineering and Microsystem, National Tsing Hua University, Hsinchu, Taiwan
- Department of Power Mechanical Engineering, National Tsing Hua University, Hsinchu, Taiwan
- * E-mail:
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Powell MR, Cleary L, Davenport M, Shea KJ, Siwy ZS. Electric-field-induced wetting and dewetting in single hydrophobic nanopores. Nat Nanotechnol 2011; 6:798-802. [PMID: 22036811 DOI: 10.1038/nnano.2011.189] [Citation(s) in RCA: 200] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2011] [Accepted: 09/28/2011] [Indexed: 05/22/2023]
Abstract
The behaviour of water in nanopores is very different from that of bulk water. Close to hydrophobic surfaces, the water density has been found to be lower than in the bulk, and if confined in a sufficiently narrow hydrophobic nanopore, water can spontaneously evaporate. Molecular dynamics simulations have suggested that a nanopore can be switched between dry and wet states by applying an electric potential across the nanopore membrane. Nanopores with hydrophobic walls could therefore create a gate system for water, and also for ionic and neutral species. Here, we show that single hydrophobic nanopores can undergo reversible wetting and dewetting due to condensation and evaporation of water inside the pores. The reversible process is observed as fluctuations between conducting and non-conducting ionic states and can be regulated by a transmembrane electric potential.
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Witters D, Vergauwe N, Vermeir S, Ceyssens F, Liekens S, Puers R, Lammertyn J. Biofunctionalization of electrowetting-on-dielectric digital microfluidic chips for miniaturized cell-based applications. Lab Chip 2011; 11:2790-4. [PMID: 21720645 DOI: 10.1039/c1lc20340a] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
In this paper we report on the controlled biofunctionalization of the hydrophobic layer of electrowetting-on-dielectric (EWOD) based microfluidic chips with the aim to execute (adherent) cell-based assays. The biofunctionalization technique involves a dry lift-off method with an easy to remove Parylene-C mask and allows the creation of spatially controlled micropatches of biomolecules in the Teflon-AF(®) layer of the chip. Compared to conventional methods, this method (i) is fully biocompatible; and (ii) leaves the hydrophobicity of the chip surface unaffected by the fabrication process, which is a crucial feature for digital microfluidic chips. In addition, full control of the geometry and the dimensions of the micropatches is achieved, allowing cells to be arrayed as cell clusters or as single cells on the digital microfluidic chip surface. The dry Parylene-C lift-off technique proves to have great potential for precise biofunctionalization of digital microfluidic chips, and can enhance their use for heterogeneous bio-assays that are of interest in various biomedical applications.
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Affiliation(s)
- Daan Witters
- BIOSYST-MeBioS, Willem de Croylaan 42, Leuven, Belgium
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Abstract
A platform capable of seamlessly unifying both optoelectrowetting and optoelectronic tweezers is presented. This enables the user to manipulate aqueous droplets (with electrowetting) as well as individual particles within those droplets (with dielectrophoresis). The device requires no photolithography and droplet/particle manipulation can occur continuously over the entire surface of the device. Droplet and 10 µm polystyrene particle speeds of up to 8 mm s(-1) and 60 µm s(-1), respectively, are demonstrated. Particle concentration within, and subsequent splitting of, a droplet is performed resulting in average concentration efficiencies of 93%. Serial concentration is also demonstrated resulting in exponentially increasing particle concentrations and a 10× concentration increase. Finally, the platform is used to select a single cell out of a cohort and subsequently encapsulate it in its own aqueous droplet.
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Affiliation(s)
- Justin K Valley
- Berkeley Sensor and Actuator Center, Department of Electrical Engineering and Computer Science, University of California Berkeley, 497 Cory Hall, Berkeley, CA 94720, USA.
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Jönsson-Niedziółka M, Lapierre F, Coffinier Y, Parry SJ, Zoueshtiagh F, Foat T, Thomy V, Boukherroub R. EWOD driven cleaning of bioparticles on hydrophobic and superhydrophobic surfaces. Lab Chip 2011; 11:490-6. [PMID: 21103534 DOI: 10.1039/c0lc00203h] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Environmental air monitoring is of great interest due to the large number of people concerned and exposed to different possible risks. From the most common particles in our environment (e.g. by-products of combustion or pollens) to more specific and dangerous agents (e.g. pathogenic micro-organisms), there are a large range of particles that need to be controlled. In this article we propose an original study on the collection of electrostatically deposited particles using electrowetting droplet displacement. A variety of particles were studied, from synthetic particles (e.g. Polystyrene Latex (PSL) microsphere) to different classes of biological particle (proteins, bacterial spores and a viral simulant). Furthermore, we have compared ElectroWetting-On-Dielectric (EWOD) collecting efficiency using either a hydrophobic or a superhydrophobic counter electrode. We observe different cleaning efficiencies, depending on the hydrophobicity of the substrate (varying from 45% to 99%). Superhydrophobic surfaces show the best cleaning efficiency with water droplets for all investigated particles (MS2 bacteriophage, BG (Bacillus atrophaeus) spores, OA (ovalbumin) proteins, and PSL).
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Abstract
Dynamic wetting and electrowetting are explored using molecular dynamics simulations. The propagation of the precursor film (PF) is fast and obeys the power law with respect to time. Against the former studies, we find the PF is no slip and solidlike. As an important application of the PF, the electro-elasto-capillarity, which is a good candidate for drug delivery at the micro- or nanoscale, is simulated and realized for the first time. Our findings may be one of the answers to the Huh-Scriven paradox and expand our knowledge of dynamic wetting and electrowetting.
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Affiliation(s)
- Quanzi Yuan
- State Key Laboratory of Nonlinear Mechanics, Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
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Nakamura M, Nagai A, Hentunen T, Salonen J, Sekijima Y, Okura T, Hashimoto K, Toda Y, Monma H, Yamashita K. Surface electric fields increase osteoblast adhesion through improved wettability on hydroxyapatite electret. ACS Appl Mater Interfaces 2009; 1:2181-2189. [PMID: 20355852 DOI: 10.1021/am900341v] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Osteoblasts are susceptible to the surface characteristics of bioceramics and stimulation from outside the cells. The purpose of this study was to evaluate the effects of electrical polarization on surface characteristics and osteoblastic adhesion. The surface characteristics revealed that electrical polarization had no effect on the surface roughness, crystallinity, and constituent elements. According to contact-angle measurements, electrically polarized hydroxyapatite (HA), which provides two kinds of surfaces, negatively charged HA (N-HA) and positively charged HA (P-HA), was even more hydrophilic than that of normal HA (O-HA). Morphological observations and quantitative analyses revealed that the typical adhered cells had a round shape on O-HA but had a spindle or fanlike spreading configuration on N-HA and P-HA 1 h after seeding. After 3 h of cultivation, the rate of the number of spread cells and the size of the focal adhesions on O-HA increased and approached that of N-HA and P-HA. However, the cell areas positively stained for actin, which indicates the degree of cell spreading, were distinctly larger on N-HA and P-HA than that on O-HA. The number of focal adhesions per cell was also less than that on N-HA and P-HA.
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Affiliation(s)
- Miho Nakamura
- Institute of Biomaterials and Bioengineering, Tokyo Medical and Dental University, 2-3-10 Kanda-Surugadai, Chiyoda, Tokyo 1010062, Japan.
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