1
|
Budiman F, Silalahi DK, Muhamad B, Fathurahman MR, Rozana M, Tanaka H. Wirelessly powered dielectrophoresis of metal oxide particles using spark-gap Tesla coil. Electrophoresis 2020; 41:2159-2165. [PMID: 33029799 DOI: 10.1002/elps.202000102] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2020] [Revised: 07/29/2020] [Accepted: 09/12/2020] [Indexed: 12/18/2022]
Abstract
Wirelessly powered dielectrophoresis (DEP) of metal oxide particles was performed using a spark-gap Tesla coil (TC). The main contribution of this work is the simplification of the conventional DEP setup that requires attaching wires directly to the electrodes. Wireless power from the TC generates a high output frequency and voltage, which corresponds to that used for the DEP. Therefore, a spark-gap TC was built and utilized to conduct the DEP process. Metal oxides (ZnO and Fe2O3) were used as targets for the assembly. The results showed that the wirelessly powered DEP technique via a TC was successful in assembling the metal oxide particles. Positive and negative DEP phenomena were observed. Positive DEP occurred during ZnO assembly, making particles chain grow 0.92 mm toward the sparks within 60 s. Negative DEP was observed during Fe2O3 assembly, where the repulsion of particles formed a void around the sparks with a 1.45 mm radius. The mechanism of this wireless DEP system is discussed.
Collapse
Affiliation(s)
- Faisal Budiman
- School of Electrical Engineering, Telkom University, Jl. Telekomunikasi no. 1, Bandung, West Java, 40257, Indonesia
- Research Center for Internet of Things, Telkom University, Jl. Telekomunikasi no. 1, Bandung, West Java, 40257, Indonesia
| | - Desri Kristina Silalahi
- School of Electrical Engineering, Telkom University, Jl. Telekomunikasi no. 1, Bandung, West Java, 40257, Indonesia
| | - Bagaskoro Muhamad
- School of Electrical Engineering, Telkom University, Jl. Telekomunikasi no. 1, Bandung, West Java, 40257, Indonesia
| | - Muhammad Rafi Fathurahman
- School of Electrical Engineering, Telkom University, Jl. Telekomunikasi no. 1, Bandung, West Java, 40257, Indonesia
| | - Monna Rozana
- Research Unit for Clean Technology, Indonesia Institute of Science, Jl. Sangkuriang - Komplek LIPI, Bandung, West Java, 40135, Indonesia
| | - Hirofumi Tanaka
- Graduate School of Life Science and Systems Engineering, Kyushu Institute of Technology, 2-4 Hibikino, Wakamatsu, Kitakyushu, Fukuoka, 808-0135, Japan
- Research Center for Neuromorphic AI Hardware, Kyushu Institute of Technology, 2-4 Hibikino, Wakamatsu, Kitakyushu, Fukuoka, 808-0135, Japan
| |
Collapse
|
2
|
Surface-enhanced Raman spectroscopy in tandem with a gradient electric field from 4-mercaptophenylboronic acid on silver nanoparticles. Mikrochim Acta 2020; 187:566. [PMID: 32929573 DOI: 10.1007/s00604-020-04550-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Accepted: 09/04/2020] [Indexed: 10/23/2022]
Abstract
The surface-enhanced Raman spectroscopy (SERS) signal of a reporter on silver nanoparticles can be effectively gained by gradient electric field application. The external electric field initiates the dielectrophoresis of nanoparticles and their electrically induced dipole-dipole interaction. Owing to dielectrophoresis, the nanoparticles are concentrated in the area of high electrical field strength. The induced dipole-dipole interaction leads to additional coagulation of nanoparticles and formation of hotspots. Both dielectrophoresis and induced dipole-dipole interaction increase the number of hotspots, which leads to a SERS signal growth. These two mechanisms of SERS signal amplification are explained by the dielectrophoresis and Derjaguin-Landau-Verwey-Overbeek theories. The benefits of the surface-enhanced Raman spectroscopy in tandem with the gradient electric field are experimentally confirmed using a SERS-active reporter, 4-mercaptophenylboronic acid which has a characteristic peak at Raman shift of 1586 cm-1, conjugated to silver nanoparticles of 32, 52, 58, and 74 nm in diameter. The SERS signal gain depends on the silver nanoparticle stability, size, and electric field strength. The limit of detection for 4-mPBA in the system under study can be calculated from the concentration plot and equals to 63 nM. The enhancement factor calculated for SERS in tandem with the gradient electric field can reach 106.Graphical abstract.
Collapse
|
3
|
Salahi A, Varhue WB, Farmehini V, Hyler AR, Schmelz EM, Davalos RV, Swami NS. Self-aligned microfluidic contactless dielectrophoresis device fabricated by single-layer imprinting on cyclic olefin copolymer. Anal Bioanal Chem 2020; 412:3881-3889. [PMID: 32372273 DOI: 10.1007/s00216-020-02667-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2019] [Revised: 04/03/2020] [Accepted: 04/16/2020] [Indexed: 12/17/2022]
Abstract
The trapping and deflection of biological cells by dielectrophoresis (DEP) at field non-uniformities in a microfluidic device is often conducted in a contactless dielectrophoresis (cDEP) mode, wherein the electrode channel is in a different layer than the sample channel, so that field penetration through the interceding barrier causes DEP above critical cut-off frequencies. In this manner, through physical separation of the electrode and sample channels, it is possible to spatially modulate electric fields with no electrode-induced damage to biological cells in the sample channel. However, since this device requires interlayer alignment of the electrode to sample channel and needs to maintain a thin interceding barrier (~ 15 μm) over the entire length over which DEP is needed (~ 1 cm), variations in alignment and microstructure fidelity cause wide variations in cDEP trapping level and frequency response across devices. We present a strategy to eliminate interlayer alignment by fabricating self-aligned electrode and sample channels, simultaneously with the interceding barrier layer (14-μm width and 50-μm depth), using a single-layer imprint and bond process on cyclic olefin copolymer. Specifically, by designing support structures, we preserve fidelity of the high aspect ratio insulating posts in the sample channel and the interceding barrier between the sample and electrode channels over the entire device footprint (~ 1 cm). The device operation is validated based on impedance measurements to quantify field penetration through the interceding barrier and by DEP trapping measurements. The presented fabrication strategy can eventually improve cDEP device manufacturing protocols to enable more reproducible DEP performance. Graphical abstract.
Collapse
Affiliation(s)
- Armita Salahi
- Department of Electrical and Computer Engineering, University of Virginia, Charlottesville, VA, 22904, USA
| | - Walter B Varhue
- Department of Electrical and Computer Engineering, University of Virginia, Charlottesville, VA, 22904, USA
| | - Vahid Farmehini
- Department of Electrical and Computer Engineering, University of Virginia, Charlottesville, VA, 22904, USA
| | | | - Eva M Schmelz
- Department of Human Nutrition, Foods and Exercise, Virginia Polytechnic Institute and State University, Blacksburg, VA, 24061, USA
| | - Rafael V Davalos
- Department of Biomedical Engineering & Mechanics, Virginia Polytechnic Institute and State University, Blacksburg, VA, 24061, USA
| | - Nathan S Swami
- Department of Electrical and Computer Engineering, University of Virginia, Charlottesville, VA, 22904, USA. .,Chemistry, University of Virginia, Charlottesville, VA, 22904, USA.
| |
Collapse
|