1
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Jenne A, von der Ecken S, Moxley-Paquette V, Soong R, Swyer I, Bastawrous M, Busse F, Bermel W, Schmidig D, Kuehn T, Kuemmerle R, Al Adwan-Stojilkovic D, Graf S, Frei T, Monette M, Wheeler AR, Simpson AJ. Integrated Digital Microfluidics NMR Spectroscopy: A Key Step toward Automated In Vivo Metabolomics. Anal Chem 2023; 95:5858-5866. [PMID: 36996326 DOI: 10.1021/acs.analchem.2c04201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/01/2023]
Abstract
Toxicity testing is currently undergoing a paradigm shift from examining apical end points such as death, to monitoring sub-lethal toxicity in vivo. In vivo nuclear magnetic resonance (NMR) spectroscopy is a key platform in this endeavor. A proof-of-principle study is presented which directly interfaces NMR with digital microfluidics (DMF). DMF is a "lab on a chip" method allowing for the movement, mixing, splitting, and dispensing of μL-sized droplets. The goal is for DMF to supply oxygenated water to keep the organisms alive while NMR detects metabolomic changes. Here, both vertical and horizontal NMR coil configurations are compared. While a horizontal configuration is ideal for DMF, NMR performance was found to be sub-par and instead, a vertical-optimized single-sided stripline showed most promise. In this configuration, three organisms were monitored in vivo using 1H-13C 2D NMR. Without support from DMF droplet exchange, the organisms quickly showed signs of anoxic stress; however, with droplet exchange, this was completely suppressed. The results demonstrate that DMF can be used to maintain living organisms and holds potential for automated exposures in future. However, due to numerous limitations of vertically orientated DMF, along with space limitations in standard bore NMR spectrometers, we recommend future development be performed using a horizontal (MRI style) magnet which would eliminate practically all the drawbacks identified here.
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Affiliation(s)
- Amy Jenne
- Department of Chemistry, University of Toronto, 80. St. George Street, Toronto, Ontario M5S 3H6, Canada
- Environmental NMR Center, University of Toronto Scarborough, 1265 Military Trail, Scarborough, Ontario M1C 1A4, Canada
| | - Sebastian von der Ecken
- Department of Chemistry, University of Toronto, 80. St. George Street, Toronto, Ontario M5S 3H6, Canada
- Nicoya, B-29 King Street East, Kitchener, Ontario N2G 2K4, Canada
| | - Vincent Moxley-Paquette
- Environmental NMR Center, University of Toronto Scarborough, 1265 Military Trail, Scarborough, Ontario M1C 1A4, Canada
| | - Ronald Soong
- Environmental NMR Center, University of Toronto Scarborough, 1265 Military Trail, Scarborough, Ontario M1C 1A4, Canada
| | - Ian Swyer
- Department of Chemistry, University of Toronto, 80. St. George Street, Toronto, Ontario M5S 3H6, Canada
| | - Monica Bastawrous
- Environmental NMR Center, University of Toronto Scarborough, 1265 Military Trail, Scarborough, Ontario M1C 1A4, Canada
| | - Falko Busse
- Bruker BioSpin GmbH, Rudolf-Plank-Str. 23, 76275 Ettlingen, Germany
| | - Wolfgang Bermel
- Bruker BioSpin GmbH, Rudolf-Plank-Str. 23, 76275 Ettlingen, Germany
| | - Daniel Schmidig
- Bruker BioSpin AG, Industriestrasse 26, 8117 Fällanden, Switzerland
| | - Till Kuehn
- Bruker BioSpin AG, Industriestrasse 26, 8117 Fällanden, Switzerland
| | - Rainer Kuemmerle
- Bruker BioSpin AG, Industriestrasse 26, 8117 Fällanden, Switzerland
| | | | - Stephan Graf
- Bruker BioSpin AG, Industriestrasse 26, 8117 Fällanden, Switzerland
| | - Thomas Frei
- Bruker BioSpin AG, Industriestrasse 26, 8117 Fällanden, Switzerland
| | - Martine Monette
- Bruker Canada Ltd., 2800 High Point Drive, Milton, Ontario L9T 6P4, Canada
| | - Aaron R Wheeler
- Department of Chemistry, University of Toronto, 80. St. George Street, Toronto, Ontario M5S 3H6, Canada
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, 160 College Street, Toronto, Ontario M5S 3E1, Canada
- Institute for Biomedical Engineering, University of Toronto, 164 College Street, Toronto, Ontario M5S 3G9, Canada
| | - Andre J Simpson
- Department of Chemistry, University of Toronto, 80. St. George Street, Toronto, Ontario M5S 3H6, Canada
- Environmental NMR Center, University of Toronto Scarborough, 1265 Military Trail, Scarborough, Ontario M1C 1A4, Canada
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2
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Li Z, Bao Q, Liu C, Li Y, Yang Y, Liu M. Recent advances in microfluidics-based bioNMR analysis. LAB ON A CHIP 2023; 23:1213-1225. [PMID: 36651305 DOI: 10.1039/d2lc00876a] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Nuclear magnetic resonance (NMR) has been used in a variety of fields due to its powerful analytical capability. To facilitate biochemical NMR (bioNMR) analysis for samples with a limited mass, a number of integrated systems have been developed by coupling microfluidics and NMR. However, there are few review papers that summarize the recent advances in the development of microfluidics-based NMR (μNMR) systems. Herein, we review the advancements in μNMR systems built on high-field commercial instruments and low-field compact platforms. Specifically, μNMR platforms with three types of typical microcoils settled in the high-field NMR instruments will be discussed, followed by summarizing compact NMR systems and their applications in biomedical point-of-care testing. Finally, a conclusion and future prospects in the field of μNMR were given.
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Affiliation(s)
- Zheyu Li
- Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology-Wuhan National Laboratory for Optoelectronics, Chinese Academy of Sciences, Wuhan 430071, China.
- University of Chinese Academy of Sciences, Beijing 10049, China
| | - Qingjia Bao
- Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology-Wuhan National Laboratory for Optoelectronics, Chinese Academy of Sciences, Wuhan 430071, China.
- University of Chinese Academy of Sciences, Beijing 10049, China
| | - Chaoyang Liu
- Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology-Wuhan National Laboratory for Optoelectronics, Chinese Academy of Sciences, Wuhan 430071, China.
- University of Chinese Academy of Sciences, Beijing 10049, China
| | - Ying Li
- Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology-Wuhan National Laboratory for Optoelectronics, Chinese Academy of Sciences, Wuhan 430071, China.
- University of Chinese Academy of Sciences, Beijing 10049, China
| | - Yunhuang Yang
- Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology-Wuhan National Laboratory for Optoelectronics, Chinese Academy of Sciences, Wuhan 430071, China.
- University of Chinese Academy of Sciences, Beijing 10049, China
| | - Maili Liu
- Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology-Wuhan National Laboratory for Optoelectronics, Chinese Academy of Sciences, Wuhan 430071, China.
- University of Chinese Academy of Sciences, Beijing 10049, China
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3
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Tong Z, Shen C, Li Q, Yin H, Mao H. Combining sensors and actuators with electrowetting-on-dielectric (EWOD): advanced digital microfluidic systems for biomedical applications. Analyst 2023; 148:1399-1421. [PMID: 36752059 DOI: 10.1039/d2an01707e] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
The concept of digital microfluidics (DMF) enables highly flexible and precise droplet manipulation at a picoliter scale, making DMF a promising approach to realize integrated, miniaturized "lab-on-a-chip" (LOC) systems for research and clinical purposes. Owing to its simplicity and effectiveness, electrowetting-on-dielectric (EWOD) is one of the most commonly studied and applied effects to implement DMF. However, complex biomedical assays usually require more sophisticated sample handling and detection capabilities than basic EWOD manipulation. Alternatively, combined systems integrating EWOD actuators and other fluidic handling techniques are essential for bringing DMF into practical use. In this paper, we briefly review the main approaches for the integration/combination of EWOD with other microfluidic manipulation methods or additional external fields for specified biomedical applications. The form of integration ranges from independently operating sub-systems to fully coupled hybrid actuators. The corresponding biomedical applications of these works are also summarized to illustrate the significance of these innovative combination attempts.
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Affiliation(s)
- Zhaoduo Tong
- State Key Laboratory of Transducer Technology, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050, China. .,Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Chuanjie Shen
- State Key Laboratory of Transducer Technology, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050, China. .,Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Qiushi Li
- State Key Laboratory of Transducer Technology, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050, China.
| | - Hao Yin
- State Key Laboratory of Transducer Technology, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050, China. .,Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Hongju Mao
- State Key Laboratory of Transducer Technology, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050, China.
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4
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“Development and application of analytical detection techniques for droplet-based microfluidics”-A review. Anal Chim Acta 2020; 1113:66-84. [DOI: 10.1016/j.aca.2020.03.011] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2019] [Revised: 03/02/2020] [Accepted: 03/05/2020] [Indexed: 01/03/2023]
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Guo J, Jiang D, Feng S, Ren C, Guo J. µ‐NMR at the point of care testing. Electrophoresis 2020; 41:319-327. [DOI: 10.1002/elps.201900329] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2019] [Revised: 12/15/2019] [Accepted: 12/15/2019] [Indexed: 11/09/2022]
Affiliation(s)
- Jiuchuan Guo
- School of Information and Communication EngineeringUniversity of Electronic Science and Technology of China Chengdu P. R. China
| | - Di Jiang
- School of Information and Communication EngineeringUniversity of Electronic Science and Technology of China Chengdu P. R. China
| | - Shilun Feng
- School of EEENanyang Technological University Singapore
| | - Chunhui Ren
- School of Information and Communication EngineeringUniversity of Electronic Science and Technology of China Chengdu P. R. China
| | - Jinhong Guo
- School of Information and Communication EngineeringUniversity of Electronic Science and Technology of China Chengdu P. R. China
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6
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Swyer I, von der Ecken S, Wu B, Jenne A, Soong R, Vincent F, Schmidig D, Frei T, Busse F, Stronks HJ, Simpson AJ, Wheeler AR. Digital microfluidics and nuclear magnetic resonance spectroscopy for in situ diffusion measurements and reaction monitoring. LAB ON A CHIP 2019; 19:641-653. [PMID: 30648175 DOI: 10.1039/c8lc01214h] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
In recent years microcoils and related structures have been developed to increase the mass sensitivity of nuclear magnetic resonance spectroscopy, allowing this extremely powerful analytical technique to be extended to small sample volumes (<5 μl). In general, microchannels have been used to deliver the samples of interest to these microcoils; however, these systems tend to have large dead volumes and require more complex fluidic connections. Here, we introduce a two-plate digital microfluidic (DMF) strategy to interface small-volume samples with NMR microcoils. In this system, a planar microcoil is surrounded by a copper plane that serves as the counter-electrode for the digital microfluidic device, allowing for precise control of droplet position and shape. This feature allows for the user-determination of the orientation of droplets relative to the main axes of the shim stack, permitting improved shimming and a more homogeneous magnetic field inside the droplet below the microcoil, which leads to improved spectral lineshape. This, along with high-fidelity droplet actuation, allows for rapid shimming strategies (developed over decades for vertically oriented NMR tubes) to be employed, permitting the determination of reaction-product diffusion coefficients as well as quantitative monitoring of reactive intermediates. We propose that this system paves the way for new and exciting applications for in situ analysis of small samples by NMR spectroscopy.
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Affiliation(s)
- Ian Swyer
- Department of Chemistry, University of Toronto, 80 St George St., Toronto, ON M5S 3H6, Canada.
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7
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Introduction. HANDHELD TOTAL CHEMICAL AND BIOLOGICAL ANALYSIS SYSTEMS 2018. [PMCID: PMC7120909 DOI: 10.1007/978-3-319-67825-2_1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
An essential part to evaluate the success of global health is the access to appropriate diagnostic tools [1]. A commendable diagnostic tool should be able to identify the disease occurred from the individuals rapidly. Especially for the infectious diseases, the turnaround time (TAT) for the diagnosis strongly affects their exacerbation level to the community. In vitro diagnostic (IVD) tool is aimed to offer a comfortable diagnosis for the patients, by taking only small specimens from the human body, e.g., blood, urine, or sputum, for analysis. Consequently, technologies enabling effective in vitro diagnosis become highly attractive for both developed and developing countries [2]. Tremendous efforts have been geared toward developing clinical-level IVD tools. Despite achieving high accuracy, the resulting TAT can be too long for diagnoses of contagious diseases like Ebola and SARS in the rural area, and the requisite of skillful operators and sophisticated equipment to perform the assays can dramatically raise the cost of the assay.
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8
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Peng Y, Jin X, Zheng Y, Han D, Liu K, Jiang L. Direct Imaging of Superwetting Behavior on Solid-Liquid-Vapor Triphase Interfaces. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2017; 29. [PMID: 28869679 DOI: 10.1002/adma.201703009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Revised: 07/17/2017] [Indexed: 05/11/2023]
Abstract
A solid-liquid-vapor interface dominated by a three-phase contact line usually serves as an active area for interfacial reactions and provides a vital clue to surface behavior. Recently, direct imaging of the triphase interface of superwetting interfaces on the microscale/nanoscale has attracted broad scientific attention for both theoretical research and practical applications, and has gradually become an efficient and intuitive approach to explore the wetting behaviors of various multiphase interfaces. Here, recent progress on characterizing the solid-liquid-vapor triphase interface on the microscale/nanoscale with diverse types of imaging apparatus is summarized. Moreover, the accurate, visible, and quantitative information that can be obtained shows the real interfacial morphology of the wetting behaviors of multiphase interfaces. On the basis of fundamental research, technical innovations in imaging and complicated multiphase interfaces of the superwetting surface are also briefly presented.
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Affiliation(s)
- Yun Peng
- Key Laboratory of Bio-Inspired Smart Interfacial Science and Technology of Ministry of Education, School of Chemistry, Beihang University, Beijing, 100191, P. R. China
| | - Xu Jin
- Research Institute of Petroleum, Exploration and Development, Petro China, Beijing, 100191, P. R. China
| | - Yongmei Zheng
- Key Laboratory of Bio-Inspired Smart Interfacial Science and Technology of Ministry of Education, School of Chemistry, Beihang University, Beijing, 100191, P. R. China
| | - Dong Han
- National Center for Nanoscience and Technology, Beijing, 100190, P. R. China
| | - Kesong Liu
- Key Laboratory of Bio-Inspired Smart Interfacial Science and Technology of Ministry of Education, School of Chemistry, Beihang University, Beijing, 100191, P. R. China
| | - Lei Jiang
- Key Laboratory of Bio-Inspired Smart Interfacial Science and Technology of Ministry of Education, School of Chemistry, Beihang University, Beijing, 100191, P. R. China
- Laboratory of Bio-inspired Smart Interface Science, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, 100190, P. R. China
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9
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Swyer I, Soong R, Dryden MDM, Fey M, Maas WE, Simpson A, Wheeler AR. Interfacing digital microfluidics with high-field nuclear magnetic resonance spectroscopy. LAB ON A CHIP 2016; 16:4424-4435. [PMID: 27757467 DOI: 10.1039/c6lc01073c] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Nuclear magnetic resonance (NMR) spectroscopy is extremely powerful for chemical analysis but it suffers from lower mass sensitivity compared to many other analytical detection methods. NMR microcoils have been developed in response to this limitation, but interfacing these coils with small sample volumes is a challenge. We introduce here the first digital microfluidic system capable of interfacing droplets of analyte with microcoils in a high-field NMR spectrometer. A finite element simulation was performed to assist in determining appropriate system parameters. After optimization, droplets inside the spectrometer could be controlled remotely, permitting the observation of processes such as xylose-borate complexation and glucose oxidase catalysis. We propose that the combination of DMF and NMR will be a useful new tool for a wide range of applications in chemical analysis.
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Affiliation(s)
- Ian Swyer
- Department of Chemistry, University of Toronto, 80 St. George St, Toronto, ON M5S 3H6, Canada.
| | - Ronald Soong
- Department of Chemistry, University of Toronto Scarborough, 1256 Military Trail, Toronto, ON M1C 1A4, Canada.
| | - Michael D M Dryden
- Department of Chemistry, University of Toronto, 80 St. George St, Toronto, ON M5S 3H6, Canada.
| | - Michael Fey
- Bruker BioSpin Corp, 15 Fortune Drive, Billerica, Massachusetts 01821-3991, USA
| | - Werner E Maas
- Bruker BioSpin Corp, 15 Fortune Drive, Billerica, Massachusetts 01821-3991, USA
| | - André Simpson
- Department of Chemistry, University of Toronto Scarborough, 1256 Military Trail, Toronto, ON M1C 1A4, Canada.
| | - Aaron R Wheeler
- Department of Chemistry, University of Toronto, 80 St. George St, Toronto, ON M5S 3H6, Canada. and Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, 160 College St, Toronto, ON M5S 3E1, Canada and Institute for Biomaterials and Biomedical Engineering, University of Toronto, 164 College St, Toronto, ON M5S 3G9, Canada
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10
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Lei KM, Mak PI, Law MK, Martins RP. A palm-size μNMR relaxometer using a digital microfluidic device and a semiconductor transceiver for chemical/biological diagnosis. Analyst 2016; 140:5129-37. [PMID: 26034784 DOI: 10.1039/c5an00500k] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Herein, we describe a micro-nuclear magnetic resonance (μNMR) relaxometer miniaturized to palm-size and electronically automated for multi-step and multi-sample chemical/biological diagnosis. The co-integration of microfluidic and microelectronic technologies enables an association between the droplet managements and μNMR assays inside a portable sub-Tesla magnet (1.2 kg, 0.46 Tesla). Targets in unprocessed biological samples, captured by specific probe-decorated magnetic nanoparticles (NPs), can be sequentially quantified by their spin-spin relaxation time (T2) via multiplexed μNMR screening. Distinct droplet samples are operated by a digital microfluidic device that electronically manages the electrowetting-on-dielectric effects over an electrode array. Each electrode (3.5 × 3.5 mm(2)) is scanned with capacitive sensing to locate the distinct droplet samples in real time. A cross-domain-optimized butterfly-coil-input semiconductor transceiver transduces between magnetic and electrical signals to/from a sub-10 μL droplet sample for high-sensitivity μNMR screening. A temperature logger senses the ambient temperature (0 to 40 °C) and a backend processor calibrates the working frequency for the transmitter to precisely excite the protons. In our experiments, the μNMR relaxometer quantifies avidin using biotinylated Iron NPs (Φ: 30 nm, [Fe]: 0.5 mM) with a sensitivity of 0.2 μM. Auto-handling and identification of two targets (avidin and water) are demonstrated and completed within 2.2 min. This μNMR relaxometer holds promise for combinatorial chemical/biological diagnostic protocols using closed-loop electronic automation.
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Affiliation(s)
- Ka-Meng Lei
- State-Key Laboratory of Analog and Mixed-Signal VLSI, University of Macau, China.
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Grisi M, Gualco G, Boero G. A broadband single-chip transceiver for multi-nuclear NMR probes. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2015; 86:044703. [PMID: 25933876 DOI: 10.1063/1.4916206] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
In this article, we present an integrated broadband complementary metal-oxide semiconductor single-chip transceiver suitable for the realization of multi-nuclear pulsed nuclear magnetic resonance (NMR) probes. The realized single-chip transceiver can be interfaced with on-chip integrated microcoils or external LC resonators operating in the range from 1 MHz to 1 GHz. The dimension of the chip is about 1 mm(2). It consists of a radio-frequency (RF) power amplifier, a low-noise RF preamplifier, a frequency mixer, an audio-frequency amplifier, and fully integrated transmit-receive switches. As specific example, we show its use for multi-nuclear NMR spectroscopy. With an integrated coil of about 150 μm external diameter, a (1)H spin sensitivity of about 1.5 × 10(13) spins/Hz(1/2) is achieved at 7 T.
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Affiliation(s)
- Marco Grisi
- Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne CH-1015, Switzerland
| | - Gabriele Gualco
- Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne CH-1015, Switzerland
| | - Giovanni Boero
- Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne CH-1015, Switzerland
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