Electron spin resonance microfluidics with subnanoliter liquid samples
Microfluidics is a well-established technique to synthesize, process, and analyze small amounts of materials for chemical, biological, medical, and environmental applications. Typically, it involves the use of reagents with a volume smaller than ~ 1 micro-l—ideally even nano- or picoliters. When th...
| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
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Elsevier
2020-06-01
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| Series: | Journal of Magnetic Resonance Open |
| Subjects: | |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S2666441020300054 |
| _version_ | 1818915836986916864 |
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| author | Nir Dayan Yakir Ishay Yaron Artzi David Cristea Benoit Driesschaert Aharon Blank |
| author_facet | Nir Dayan Yakir Ishay Yaron Artzi David Cristea Benoit Driesschaert Aharon Blank |
| author_sort | Nir Dayan |
| collection | DOAJ |
| description | Microfluidics is a well-established technique to synthesize, process, and analyze small amounts of materials for chemical, biological, medical, and environmental applications. Typically, it involves the use of reagents with a volume smaller than ~ 1 micro-l—ideally even nano- or picoliters. When the sample of interest contains paramagnetic species, it can in principle be quantified and analyzed by electron spin resonance (ESR) spectroscopy. However, conventional ESR is typically carried out with a sample volume of ~ 1 ml, thereby making it incompatible with most microfluidics applications. Here we show that by using a new class of miniature surface resonators combined with photolithography to prepare microfluidic patterns, ESR can be applied to measure small liquid samples, down to picoliter volumes, without considerably sacrificing concentration sensitivity. Our experiments, carried out with resonators whose mode volumes range from ~1 to 3.6 nL, showed that with a sample volume of ~0.25 nL good signals could be obtained from solutions with spin concentrations of less than 0.1 μM. The advantage of using microfluidics ESR is evident in our work, not only because it facilitates the use of a very small sample volume, but also because it makes it possible to apply huge ( ~ 1000 T/m) and fast ( ~ 1 μs) pulsed magnetic field gradients to the sample. This is a key capability to measuring unique properties such as nanoscale real-space diffusion and quantum spin diffusion. All our experiments are performed at room temperature, making our technique compatible with future microfluidics applications that might employ a complete system of compact resonators, microfluidic chips, miniature magnets, and a compact ESR-on-a-chip spectrometer. This could result in a completely new approach to processing and measuring paramagnetic liquid samples for use in a variety of chemical, biological, medical, and environmental applications. |
| first_indexed | 2024-12-20T00:08:37Z |
| format | Article |
| id | doaj.art-ec628091437343ee8c6545d6767b8d14 |
| institution | Directory Open Access Journal |
| issn | 2666-4410 |
| language | English |
| last_indexed | 2024-12-20T00:08:37Z |
| publishDate | 2020-06-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Journal of Magnetic Resonance Open |
| spelling | doaj.art-ec628091437343ee8c6545d6767b8d142022-12-21T20:00:35ZengElsevierJournal of Magnetic Resonance Open2666-44102020-06-012100005Electron spin resonance microfluidics with subnanoliter liquid samplesNir Dayan0Yakir Ishay1Yaron Artzi2David Cristea3Benoit Driesschaert4Aharon Blank5Schulich Faculty of Chemistry, Technion – Israel Institute of Technology, Haifa, 3200003, IsraelSchulich Faculty of Chemistry, Technion – Israel Institute of Technology, Haifa, 3200003, IsraelSchulich Faculty of Chemistry, Technion – Israel Institute of Technology, Haifa, 3200003, IsraelSchulich Faculty of Chemistry, Technion – Israel Institute of Technology, Haifa, 3200003, IsraelDepartment of Pharmaceutical Sciences, School of Pharmacy and In Vivo Multifunctional Magnetic Resonance Center, West Virginia University, Morgantown, WV, 26506 (USA)Schulich Faculty of Chemistry, Technion – Israel Institute of Technology, Haifa, 3200003, Israel; Corresponding author.Microfluidics is a well-established technique to synthesize, process, and analyze small amounts of materials for chemical, biological, medical, and environmental applications. Typically, it involves the use of reagents with a volume smaller than ~ 1 micro-l—ideally even nano- or picoliters. When the sample of interest contains paramagnetic species, it can in principle be quantified and analyzed by electron spin resonance (ESR) spectroscopy. However, conventional ESR is typically carried out with a sample volume of ~ 1 ml, thereby making it incompatible with most microfluidics applications. Here we show that by using a new class of miniature surface resonators combined with photolithography to prepare microfluidic patterns, ESR can be applied to measure small liquid samples, down to picoliter volumes, without considerably sacrificing concentration sensitivity. Our experiments, carried out with resonators whose mode volumes range from ~1 to 3.6 nL, showed that with a sample volume of ~0.25 nL good signals could be obtained from solutions with spin concentrations of less than 0.1 μM. The advantage of using microfluidics ESR is evident in our work, not only because it facilitates the use of a very small sample volume, but also because it makes it possible to apply huge ( ~ 1000 T/m) and fast ( ~ 1 μs) pulsed magnetic field gradients to the sample. This is a key capability to measuring unique properties such as nanoscale real-space diffusion and quantum spin diffusion. All our experiments are performed at room temperature, making our technique compatible with future microfluidics applications that might employ a complete system of compact resonators, microfluidic chips, miniature magnets, and a compact ESR-on-a-chip spectrometer. This could result in a completely new approach to processing and measuring paramagnetic liquid samples for use in a variety of chemical, biological, medical, and environmental applications.http://www.sciencedirect.com/science/article/pii/S2666441020300054EPRESRMicrofluidicsMicroresonatorsDiffusion |
| spellingShingle | Nir Dayan Yakir Ishay Yaron Artzi David Cristea Benoit Driesschaert Aharon Blank Electron spin resonance microfluidics with subnanoliter liquid samples Journal of Magnetic Resonance Open EPR ESR Microfluidics Microresonators Diffusion |
| title | Electron spin resonance microfluidics with subnanoliter liquid samples |
| title_full | Electron spin resonance microfluidics with subnanoliter liquid samples |
| title_fullStr | Electron spin resonance microfluidics with subnanoliter liquid samples |
| title_full_unstemmed | Electron spin resonance microfluidics with subnanoliter liquid samples |
| title_short | Electron spin resonance microfluidics with subnanoliter liquid samples |
| title_sort | electron spin resonance microfluidics with subnanoliter liquid samples |
| topic | EPR ESR Microfluidics Microresonators Diffusion |
| url | http://www.sciencedirect.com/science/article/pii/S2666441020300054 |
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