1
|
Voinov MA, Nunn N, Rana R, Davidsson A, Smirnov AI, Smirnova TI. Measuring local pH at interfaces from molecular tumbling: A concept for designing EPR-active pH-sensitive labels and probes. Org Biomol Chem 2024; 22:3652-3667. [PMID: 38647161 DOI: 10.1039/d4ob00167b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/25/2024]
Abstract
Molecular probes and indicators are broadly employed for pH measurements in bulk media and at interfaces. The underlying physical principle of pH measurements of most of these probes is based on a change in the electronic structure that, for example, results in a shift of the emission peak of the fluorescence probes, changes in NMR chemical shifts due to the affected electronic shielding, or magnetic parameters of pH-sensitive nitroxides as measured by EPR. Here we explore another concept for measuring local protonation state of molecular tags based on changes in rotational dynamics of electron spin-bearing moieties that are readily detected by conventional continuous wave X-band EPR. Such changes are especially pronounced at biological interfaces, such as lipid bilayer membranes, due to the probe interactions with adjacent charges and polarizable dipoles. The concept was demonstrated by synthesizing a series of pH-sensitive nitroxides and spin-labelled phospholipids. EPR spectra of these newly synthesized nitroxides exhibit relatively small - about 0.5 G - changes in isotropic nitrogen hyperfine coupling constant upon reversible protonation. However, spin-labelled phospholipids incorporated into lipid bilayers demonstrated almost 6-fold change in rotational correlation time upon protonation, readily allowing for pKa determination from large changes in EPR spectra. The demonstrated concept of EPR-based pH measurements leads to a broader range of potential nitroxide structures that can serve as molecular pH sensors at the desired pH range and, thus, facilitates further development of spin-labelling EPR methods to study electrostatic phenomena at chemical and biological interfaces.
Collapse
Affiliation(s)
- Maxim A Voinov
- Department of Chemistry, North Carolina State University, 2620 Yarbrough Drive, Raleigh, NC 27695, USA.
| | - Nicholas Nunn
- Department of Chemistry, North Carolina State University, 2620 Yarbrough Drive, Raleigh, NC 27695, USA.
| | - Roshan Rana
- Department of Chemistry, North Carolina State University, 2620 Yarbrough Drive, Raleigh, NC 27695, USA.
| | - Atli Davidsson
- Department of Chemistry, North Carolina State University, 2620 Yarbrough Drive, Raleigh, NC 27695, USA.
| | - Alex I Smirnov
- Department of Chemistry, North Carolina State University, 2620 Yarbrough Drive, Raleigh, NC 27695, USA.
| | - Tatyana I Smirnova
- Department of Chemistry, North Carolina State University, 2620 Yarbrough Drive, Raleigh, NC 27695, USA.
| |
Collapse
|
2
|
Kujawa M, Motała S, Gonet M, Pietrzyk R, Czechowski T, Baranowski M. Low-cost, programmable infusion pump with bolus mode for in-vivo imaging. HARDWAREX 2021; 9:e00194. [PMID: 35492061 PMCID: PMC9041266 DOI: 10.1016/j.ohx.2021.e00194] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Revised: 03/17/2021] [Accepted: 03/18/2021] [Indexed: 05/09/2023]
Abstract
Syringe pumps are routinely used in biomedical imaging laboratories for delivering contrast agents and either infusing or injecting a precise amount of liquids. Commercial syringe pumps that are developed by specialized companies are expensive and only have standard functions, which often do not meet the requirements of individual experiments. In this paper, we demonstrate an open-source single syringe pump with the possibility of adapting to the needs of a researcher. The device that was designed, is controlled by an Arduino Leonardo, along with the stepper motor driver. For sending commands and receiving the current plunger position, a C# software was developed with serial communication via USB. Additionally, the 3D models were made in a universal way, which allows for the use of any syringe size. An example of the application of the syringe pump for biomedical applications was demonstrated using electron resonance imaging (ERI). The single syringe pump tests were demonstrated by simulating the filling of a particular volume inside the resonator. This example reflects the clearance process after an intravascular (I.V) drug administration in the murine model. The experiments were performed on an ERI TM 600 tomograph. The results confirmed that the designed syringe pump allowed for controlling the infusion speed and injected volume. Moreover, we present a user-friendly and open-source graphical interface that is a low-cost alternative for commercial devices.
Collapse
Affiliation(s)
- Maciej Kujawa
- Faculty of Physics, Adam Mickiewicz University, Poznan, Poland
| | - Szymon Motała
- Faculty of Physics, Adam Mickiewicz University, Poznan, Poland
| | - Michał Gonet
- Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Poland
| | - Rafał Pietrzyk
- Faculty of Physics, Adam Mickiewicz University, Poznan, Poland
| | | | - Mikołaj Baranowski
- Faculty of Physics, Adam Mickiewicz University, Poznan, Poland
- Novilet, Poznan, Poland
- Corresponding author at: Faculty of Physics, Adam Mickiewicz University, Poznan, Poland.
| |
Collapse
|
3
|
Biller JR, McPeak JE. EPR Everywhere. APPLIED MAGNETIC RESONANCE 2021; 52:1113-1139. [PMID: 33519097 PMCID: PMC7826499 DOI: 10.1007/s00723-020-01304-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/09/2020] [Revised: 10/16/2020] [Accepted: 12/06/2020] [Indexed: 06/12/2023]
Abstract
This review is inspired by the contributions from the University of Denver group to low-field EPR, in honor of Professor Gareth Eaton's 80th birthday. The goal is to capture the spirit of innovation behind the body of work, especially as it pertains to development of new EPR techniques. The spirit of the DU EPR laboratory is one that never sought to limit what an EPR experiment could be, or how it could be applied. The most well-known example of this is the development and recent commercialization of rapid-scan EPR. Both of the Eatons have made it a point to remain knowledgeable on the newest developments in electronics and instrument design. To that end, our review touches on the use of miniaturized electronics and applications of single-board spectrometers based on software-defined radio (SDR) implementations and single-chip voltage-controlled oscillator (VCO) arrays. We also highlight several non-traditional approaches to the EPR experiment such as an EPR spectrometer with a "wand" form factor for analysis of the OxyChip, the EPR-MOUSE which enables non-destructive in situ analysis of many non-conforming samples, and interferometric EPR and frequency swept EPR as alternatives to classical high Q resonant structures.
Collapse
Affiliation(s)
| | - Joseph E. McPeak
- University of Denver, Denver, CO 80210 USA
- Berlin Joint EPR Laboratory and EPR4Energy, Department Spins in Energy Conversion and Quantum Information Science (ASPINS), Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Hahn-Meitner-Platz 1, 14109 Berlin, Germany
| |
Collapse
|
4
|
Gonet M, Epel B, Elas M. Data processing of 3D and 4D in-vivo electron paramagnetic resonance imaging co-registered with ultrasound. 3D printing as a registration tool. COMPUTERS & ELECTRICAL ENGINEERING : AN INTERNATIONAL JOURNAL 2019; 74:130-137. [PMID: 30820068 PMCID: PMC6388699 DOI: 10.1016/j.compeleceng.2019.01.012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
We present the concept of image registration using ultrasound (US) and electron paramagnetic resonance (EPR) imaging and discuss the benefits of this solution, as well as its limitations. Both phantoms and murine tumors were used to test US and EPR image co-registration. Comparison of dental molding cast immobilization and predesigned cradle revealed that the latter approach is more effective in stabilizing the fiducial position. In vivo imaging of mouse tumors, image registration and comparison of fiducials system for 3D spatial as well as 4D spatial-spectral EPR imaging supported by 3D US were demonstrated. Ultrasound may provide a convenient alternative to other anatomical imaging methods for image registration in preclinical research. Of particular interest is a fusion of US tissue structure, doppler vascular function and EPR oxygen or redox imaging.
Collapse
Affiliation(s)
- M Gonet
- 1. Department of Biophysics, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Krakow, Poland
- 3. Novilet, Poznan, Poland
| | - B Epel
- 2. Department of Radiation and Cellular Oncology, and Center for EPR Imaging In Vivo Physiology, University of Chicago, Chicago, IL 60637, United States
| | - M Elas
- 1. Department of Biophysics, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Krakow, Poland
| |
Collapse
|
5
|
Khramtsov VV, Bobko AA, Tseytlin M, Driesschaert B. Exchange Phenomena in the Electron Paramagnetic Resonance Spectra of the Nitroxyl and Trityl Radicals: Multifunctional Spectroscopy and Imaging of Local Chemical Microenvironment. Anal Chem 2017; 89:4758-4771. [PMID: 28363027 PMCID: PMC5513151 DOI: 10.1021/acs.analchem.6b03796] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
This Feature overviews the basic principles of using stable organic radicals involved in reversible exchange processes as functional paramagnetic probes. We demonstrate that these probes in combination with electron paramagnetic resonance (EPR)-based spectroscopy and imaging techniques provide analytical tools for quantitative mapping of critical parameters of local chemical microenvironment. The Feature is written to be understandable to people who are laymen to the EPR field in anticipation of future progress and broad application of these tools in biological systems, especially in vivo, over the next years.
Collapse
Affiliation(s)
- Valery V. Khramtsov
- In Vivo Multifunctional Magnetic Resonance center, Robert C. Byrd Health Sciences Center, West Virginia University, Morgantown, West Virginia 26506, United States
- Department of Biochemistry, West Virginia University School of Medicine, Morgantown, West Virginia 26506, United States
| | - Andrey A. Bobko
- In Vivo Multifunctional Magnetic Resonance center, Robert C. Byrd Health Sciences Center, West Virginia University, Morgantown, West Virginia 26506, United States
- Department of Biochemistry, West Virginia University School of Medicine, Morgantown, West Virginia 26506, United States
| | - Mark Tseytlin
- In Vivo Multifunctional Magnetic Resonance center, Robert C. Byrd Health Sciences Center, West Virginia University, Morgantown, West Virginia 26506, United States
- Department of Biochemistry, West Virginia University School of Medicine, Morgantown, West Virginia 26506, United States
| | - Benoit Driesschaert
- In Vivo Multifunctional Magnetic Resonance center, Robert C. Byrd Health Sciences Center, West Virginia University, Morgantown, West Virginia 26506, United States
- Department of Biochemistry, West Virginia University School of Medicine, Morgantown, West Virginia 26506, United States
| |
Collapse
|
6
|
Campbell JP, Ryan JT, Shrestha PR, Liu Z, Vaz C, Kim JH, Georgiou V, Cheung KP. Electron Spin Resonance Scanning Probe Spectroscopy for Ultrasensitive Biochemical Studies. Anal Chem 2015; 87:4910-6. [DOI: 10.1021/acs.analchem.5b00487] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
- Jason P. Campbell
- National Institute of Standards and Technology, 100 Bureau Drive, MS 8120, Gaithersburg, Maryland 20899, United States
| | - Jason T. Ryan
- National Institute of Standards and Technology, 100 Bureau Drive, MS 8120, Gaithersburg, Maryland 20899, United States
| | - Pragya R. Shrestha
- National Institute of Standards and Technology, 100 Bureau Drive, MS 8120, Gaithersburg, Maryland 20899, United States
| | - Zhanglong Liu
- National Institute of Standards and Technology, 100 Bureau Drive, MS 8120, Gaithersburg, Maryland 20899, United States
| | - Canute Vaz
- National Institute of Standards and Technology, 100 Bureau Drive, MS 8120, Gaithersburg, Maryland 20899, United States
| | - Ji-Hong Kim
- National Institute of Standards and Technology, 100 Bureau Drive, MS 8120, Gaithersburg, Maryland 20899, United States
| | - Vasileia Georgiou
- National Institute of Standards and Technology, 100 Bureau Drive, MS 8120, Gaithersburg, Maryland 20899, United States
- Department
of Electrical and Computer Engineering, George Mason University, 4400 University Drive, Fairfax, Virginia 22030, United States
| | - Kin P. Cheung
- National Institute of Standards and Technology, 100 Bureau Drive, MS 8120, Gaithersburg, Maryland 20899, United States
| |
Collapse
|
7
|
Takahashi W, Bobko AA, Dhimitruka I, Hirata H, Zweier JL, Samouilov A, Khramtsov VV. Proton-Electron Double-Resonance Imaging of pH using phosphonated trityl probe. APPLIED MAGNETIC RESONANCE 2014; 45:817-826. [PMID: 25530673 PMCID: PMC4268155 DOI: 10.1007/s00723-014-0570-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Variable Radio Frequency Proton-Electron Double-Resonance Imaging (VRF PEDRI) enables extracting a functional map from a limited number of images acquired at pre-selected EPR frequencies using specifically designed paramagnetic probes with high quality spatial resolution and short acquisition times. In this work we explored potential of VRF PEDRI for pH mapping of aqueous samples using recently synthesized pH-sensitive phosphonated trityl radical, pTR. The ratio of Overhauser enhancements measured at each pixel at two different excitation frequencies corresponding to the resonances of protonated and deprotonated forms of pTR probe allows for a pH map extraction. Long relaxation times of pTR allow for pH mapping at EPR irradiation power as low as 1.25 W during 130 s acquisition time with spatial resolution of about 1 mm. This is particularly important for in vivo applications enabling one to avoid sample overheating by reducing RF power deposition.
Collapse
Affiliation(s)
- Wataru Takahashi
- Division of Pulmonary, Allergy, Critical Care & Sleep Medicine, Department of Internal Medicine and Dorothy M. Davis Heart & Lung Research Institute, The Ohio State University, Columbus, OH, USA ; Division of Bioengineering and Bioinformatics, Graduate School of Information Science and Technology, Hokkaido University, Sapporo, Japan
| | - Andrey A Bobko
- Division of Pulmonary, Allergy, Critical Care & Sleep Medicine, Department of Internal Medicine and Dorothy M. Davis Heart & Lung Research Institute, The Ohio State University, Columbus, OH, USA
| | - Ilirian Dhimitruka
- Division of Pulmonary, Allergy, Critical Care & Sleep Medicine, Department of Internal Medicine and Dorothy M. Davis Heart & Lung Research Institute, The Ohio State University, Columbus, OH, USA
| | - Hiroshi Hirata
- Division of Bioengineering and Bioinformatics, Graduate School of Information Science and Technology, Hokkaido University, Sapporo, Japan
| | - Jay L Zweier
- Division of Cardiology and Dorothy M. Davis Heart & Lung Research Institute, Department of Internal Medicine, The Ohio State University, Columbus, OH, USA
| | - Alexandre Samouilov
- Division of Cardiology and Dorothy M. Davis Heart & Lung Research Institute, Department of Internal Medicine, The Ohio State University, Columbus, OH, USA
| | - Valery V Khramtsov
- Division of Pulmonary, Allergy, Critical Care & Sleep Medicine, Department of Internal Medicine and Dorothy M. Davis Heart & Lung Research Institute, The Ohio State University, Columbus, OH, USA
| |
Collapse
|
8
|
Sundramoorthy SV, Epel B, Halpern HJ. Orthogonal resonators for pulse in vivo electron paramagnetic imaging at 250 MHz. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2014; 240:45-51. [PMID: 24530507 PMCID: PMC3974126 DOI: 10.1016/j.jmr.2013.12.015] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2013] [Revised: 12/03/2013] [Accepted: 12/27/2013] [Indexed: 05/13/2023]
Abstract
A 250 MHz bimodal resonator with a 19 mm internal diameter for in vivo pulse electron paramagnetic resonance (EPR) imaging is presented. Two separate coaxial cylindrical resonators inserted one into another were used for excitation and detection. The Alderman-Grant excitation resonator (AGR) showed the highest efficiency among all the excitation resonators tested. The magnetic field of AGR is confined to the volume of the detection resonator, which results in highly efficient use of the radio frequency power. A slotted inner single loop single gap resonator (SLSG LGR), coaxial to the AGR, was used for signal detection. The resulting bimodal resonator (AG/LGR) has two mutually orthogonal magnetic field modes; one of them has the magnetic field in the axial direction. The resonator built in our laboratory achieved 40 dB isolation over 20 MHz bandwidth with quality factors of detection and excitation resonators of 36 and 11 respectively. Considerable improvement of the B1 homogeneity and EPR image quality in comparison with reflection loop-gap resonator of similar size and volume was observed.
Collapse
Affiliation(s)
- Subramanian V Sundramoorthy
- Center for EPR Imaging In Vivo Physiology, Department of Radiation and Cellular Oncology, University of Chicago, Chicago, IL 60637, USA
| | - Boris Epel
- Center for EPR Imaging In Vivo Physiology, Department of Radiation and Cellular Oncology, University of Chicago, Chicago, IL 60637, USA.
| | - Howard J Halpern
- Center for EPR Imaging In Vivo Physiology, Department of Radiation and Cellular Oncology, University of Chicago, Chicago, IL 60637, USA.
| |
Collapse
|
9
|
Samouilov A, Efimova OV, Bobko AA, Sun Z, Petryakov S, Eubank TD, Trofimov DG, Kirilyuk IA, Grigor'ev IA, Takahashi W, Zweier JL, Khramtsov VV. In vivo proton-electron double-resonance imaging of extracellular tumor pH using an advanced nitroxide probe. Anal Chem 2014; 86:1045-52. [PMID: 24372284 DOI: 10.1021/ac402230h] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A variable radio frequency proton-electron double-resonance imaging (VRF PEDRI) approach for pH mapping of aqueous samples has been recently developed (Efimova et al. J. Magn. Reson. 2011, 209, 227-232). A pH map is extracted from two PEDRI acquisitions performed at electron paramagnetic resonance (EPR) frequencies of protonated and unprotonated forms of a pH-sensitive probe. To translate VRF PEDRI to an in vivo setting, an advanced pH probe was synthesized. Probe deuteration resulted in a narrow spectral line of 1.2 G compared to a nondeuterated analogue line width of 2.1 G allowing for an increase of Overhauser enhancements and reduction in rf power deposition. Binding of the probe to the cell-impermeable tripeptide, glutathione (GSH), allows for targeting to extracellular tissue space for monitoring extracellular tumor acidosis, a prognostic factor in tumor pathophysiology. The probe demonstrated pH sensitivity in the 5.8-7.8 range, optimum for measurement of acidic extracellular tumor pH (pH(e)). In vivo VRF PEDRI was performed on Met-1 tumor-bearing mice. Compared to normal mammary glands with a neutral mean pH(e) (7.1 ± 0.1), we observed broader pH distribution with acidic mean pH(e) (6.8 ± 0.1) in tumor tissue. In summary, VRF PEDRI in combination with a newly developed pH probe provides an analytical approach for spatially resolved noninvasive pHe monitoring, in vivo.
Collapse
Affiliation(s)
- Alexandre Samouilov
- The Dorothy M. Davis Heart and Lung Research Institute: ‡Division of Pulmonary, Allergy, Critical Care, and Sleep Medicine, and §Division of Cardiovascular Medicine, Department of Internal Medicine, The Ohio State University , Columbus, Ohio 43210, United States
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|