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Mitschang L, Korchak S, Kilian W, Riemer T. Comprehensive Quantitative and Calibration-Free Evaluation of Hyperpolarized Xenon-Host Interaction by Multiparametric NMR. Anal Chem 2022; 94:2561-2568. [PMID: 35089685 DOI: 10.1021/acs.analchem.1c04482] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The probing of microscopic environments by hyperpolarized xenon NMR has spurred investigations in supramolecular chemistry as well as important biosensing and molecular imaging applications. While xenon exchange with host structures at micromolar concentrations and below can be readily detected, a quantitative analysis is limited, requiring complementary experimentation by different methodologies and thus lacking completeness and compromising the validity and comparability of numerical results. Here, a new NMR measurement and data analysis approach is introduced for the comprehensive characterization of the host-xenon binding dynamics. The application of chemical exchange saturation transfer of hyperpolarized 129Xe under parametric modulation of the saturation RF amplitude and xenon gas saturation of the solution enables a delineation of exchange mechanisms and, through modeling, a numerical estimation of the various reaction rate constants (and thus magnetization exchange rate constants), the xenon affinity, and the total host molecule concentration. Only the numerical xenon solubility is additionally required for input, a quantity that has a low impact on the measurement uncertainty and is derivable from metrological data collections. Signal calibration by a reference material may thus be avoided, qualifying the method as calibration-free. For demonstration a xenon exchange with the host cucurbit[6]uril at low concentration is investigated, with the numerical results being validated by standard quantitative NMR data obtained at high concentration. The readiness to evaluate xenon exchange for the one sample at hand and in a single experimental attempt by the proposed method may allow comprehensive quantitative studies in supramolecular chemistry, biomacromolecular structure and dynamics, and sensing.
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Affiliation(s)
- Lorenz Mitschang
- Physikalisch-Technische Bundesanstalt Braunschweig und Berlin (PTB), Abbestraße 2-12, 10587 Berlin, Germany
| | - Sergey Korchak
- Physikalisch-Technische Bundesanstalt Braunschweig und Berlin (PTB), Abbestraße 2-12, 10587 Berlin, Germany
| | - Wolfgang Kilian
- Physikalisch-Technische Bundesanstalt Braunschweig und Berlin (PTB), Abbestraße 2-12, 10587 Berlin, Germany
| | - Thomas Riemer
- University of Leipzig, Institute of Medical Physics and Biophysics, Medical Department, Härtelstraße 16-18, 04107 Leipzig, Germany
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2
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Abstract
The use of magnetic resonance imaging (MRI) and spectroscopy (MRS) in the clinical setting enables the acquisition of valuable anatomical information in a rapid, non-invasive fashion. However, MRI applications for identifying disease-related biomarkers are limited due to low sensitivity at clinical magnetic field strengths. The development of hyperpolarized (hp) 129Xe MRI/MRS techniques as complements to traditional 1H-based imaging has been a burgeoning area of research over the past two decades. Pioneering experiments have shown that hp 129Xe can be encapsulated within host molecules to generate ultrasensitive biosensors. In particular, xenon has high affinity for cryptophanes, which are small organic cages that can be functionalized with affinity tags, fluorophores, solubilizing groups, and other moieties to identify biomedically relevant analytes. Cryptophane sensors designed for proteins, metal ions, nucleic acids, pH, and temperature have achieved nanomolar-to-femtomolar limits of detection via a combination of 129Xe hyperpolarization and chemical exchange saturation transfer (CEST) techniques. This review aims to summarize the development of cryptophane biosensors for 129Xe MRI applications, while highlighting innovative biosensor designs and the consequent enhancements in detection sensitivity, which will be invaluable in expanding the scope of 129Xe MRI. This review aims to summarize the development of cryptophane biosensors for 129Xe MRI applications, while highlighting innovative biosensor designs and the consequent enhancements in detection sensitivity, which will be invaluable in expanding the scope of 129Xe MRI.![]()
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Affiliation(s)
- Serge D Zemerov
- Department of Chemistry, University of Pennsylvania, 231 South 34 St., Philadelphia, PA 19104-6323, USA
| | - Ivan J Dmochowski
- Department of Chemistry, University of Pennsylvania, 231 South 34 St., Philadelphia, PA 19104-6323, USA
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3
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Jiang W, Guo Q, Luo Q, Zhang X, Yuan Y, Li H, Zhou X. Molecular Concentration Determination Using Long-Interval Chemical Exchange Inversion Transfer (CEIT) NMR Spectroscopy. J Phys Chem Lett 2021; 12:8652-8657. [PMID: 34472873 DOI: 10.1021/acs.jpclett.1c02239] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Functionalized hyperpolarized xenon "cage" molecules have often been used for ultrasensitive detection of biomolecules and microenvironment properties. However, the rapid and accurate measurement of molecule concentration is still a challenge. Here, we report a molecule concentration measurement method using long-interval chemical exchange inversion transfer (CEIT) NMR spectroscopy. The molecule concentration can be quantitatively measured with only 2 scans, which shortens the acquisition time by about 10 times compared to conventional Hyper-CEST (chemical exchange saturation transfer) z-spectrum method. Moreover, we found that the accuracy of concentration determination would be the best when the CEIT effect is 1-1/e or close to it, and a relative deviation of CrA-(COOH)6 less than ±1% has been achieved by only a one-step optimization of the number of cycles. The proposed method enables efficient and accurate determination of molecule concentration, which provides a potential way for rapid quantitative molecular imaging applications.
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Affiliation(s)
- Weiping Jiang
- 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, Chinese Academy of Sciences-Wuhan National Laboratory for Optoelectronics, Wuhan 430071, People's Republic of China
- University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
| | - Qianni Guo
- 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, Chinese Academy of Sciences-Wuhan National Laboratory for Optoelectronics, Wuhan 430071, People's Republic of China
- University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
| | - Qing Luo
- 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, Chinese Academy of Sciences-Wuhan National Laboratory for Optoelectronics, Wuhan 430071, People's Republic of China
| | - Xiaoxiao Zhang
- 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, Chinese Academy of Sciences-Wuhan National Laboratory for Optoelectronics, Wuhan 430071, People's Republic of China
| | - Yaping Yuan
- 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, Chinese Academy of Sciences-Wuhan National Laboratory for Optoelectronics, Wuhan 430071, People's Republic of China
- University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
| | - Haidong 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, Chinese Academy of Sciences-Wuhan National Laboratory for Optoelectronics, Wuhan 430071, People's Republic of China
- University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
| | - Xin Zhou
- 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, Chinese Academy of Sciences-Wuhan National Laboratory for Optoelectronics, Wuhan 430071, People's Republic of China
- University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
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4
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Cohen Y, Slovak S, Avram L. Solution NMR of synthetic cavity containing supramolecular systems: what have we learned on and from? Chem Commun (Camb) 2021; 57:8856-8884. [PMID: 34486595 DOI: 10.1039/d1cc02906a] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
NMR has been instrumental in studies of both the structure and dynamics of molecular systems for decades, so it is not surprising that NMR has played a pivotal role in the study of host-guest complexes and supramolecular systems. In this mini-review, selected examples will be used to demonstrate the added value of using (multiparametric) NMR for studying macrocycle-based host-guest and supramolecular systems. We will restrict the discussion to synthetic host systems having a cavity that can engulf their guests thus restricting them into confined spaces. So discussion of selected examples of cavitands, cages, capsules and their complexes, aggregates and polymers as well as organic cages and porous liquids and other porous materials will be used to demonstrate the insights that have been gathered from the extracted NMR parameters when studying such systems emphasizing the information obtained from somewhat less routine NMR methods such as diffusion NMR, diffusion ordered spectroscopy (DOSY) and chemical exchange saturation transfer (CEST) and their variants. These selected examples demonstrate the impact that the results and findings from these NMR studies have had on our understanding of such systems and on the developments in various research fields.
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Affiliation(s)
- Yoram Cohen
- School of Chemistry, The Sackler Faculty of Exact Sciences, Tel Aviv University, Ramat Aviv, 699781, Tel Aviv, Israel.
| | - Sarit Slovak
- School of Chemistry, The Sackler Faculty of Exact Sciences, Tel Aviv University, Ramat Aviv, 699781, Tel Aviv, Israel.
| | - Liat Avram
- Faculty of Chemistry, Weizmann Institute of Science, Rehovot 7610001, Israel
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5
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Abstract
Cryptophane host molecules provide ultrasensitive contrast agents for 129Xe NMR/MRI. To investigate key features of cryptophane-Xe sensing behavior, we designed a novel water-soluble cryptophane with a pendant hydrophobic adamantyl moiety, which has good affinity for a model receptor, beta-cyclodextrin (β-CD). Adamantyl-functionalized cryptophane-A (AFCA) was synthesized and characterized for Xe affinity, 129Xe NMR signal, and aggregation state at varying AFCA and β-CD concentrations. The Xe-AFCA association constant was determined by fluorescence quenching, KA = 114,000 ± 5000 M-1 at 293 K, which is the highest reported affinity for a cryptophane host in phosphate-buffered saline (pH 7.2). No hyperpolarized (hp) 129Xe NMR peak corresponding to AFCA-bound Xe was directly observed at high (100 μM) AFCA concentration, where small cryptophane aggregates were observed, and was only detected at low (15 μM) AFCA concentration, where the sensor remained fully monomeric in solution. Additionally, we observed no change in the chemical shift of AFCA-encapsulated 129Xe after β-CD binding to the adamantyl moiety and a concomitant lack of change in the size distribution of the complex, suggesting that a change in the aggregation state is necessary to elicit a 129Xe NMR chemical shift in cryptophane-based sensing. These results aid in further elucidating the recently discovered aggregation phenomenon, highlight limitations of cryptophane-based Xe sensing, and offer insights into the design of monomeric, high-affinity Xe sensors.
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Affiliation(s)
- Serge D Zemerov
- Department of Chemistry, University of Pennsylvania, 231 S 34th Street, Philadelphia, Pennsylvania 19104, United States
| | - Yannan Lin
- Department of Chemistry, University of Pennsylvania, 231 S 34th Street, Philadelphia, Pennsylvania 19104, United States
| | - Ivan J Dmochowski
- Department of Chemistry, University of Pennsylvania, 231 S 34th Street, Philadelphia, Pennsylvania 19104, United States
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6
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Fernando PUI, Shepelytskyi Y, Cesana PT, Wade A, Grynko V, Mendieta AM, Seveney LE, Brown JD, Hane FT, Albert MS, DeBoef B. Decacationic Pillar[5]arene: A New Scaffold for the Development of 129Xe MRI Imaging Agents. ACS Omega 2020; 5:27783-27788. [PMID: 33163761 PMCID: PMC7643082 DOI: 10.1021/acsomega.0c02565] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2020] [Accepted: 10/07/2020] [Indexed: 05/16/2023]
Abstract
A decacationic water-soluble pillar[5]arene possessing a nonsolvated hydrophobic core has been designed and synthesized. This supramolecular host is capable of binding xenon, as evidenced by hyperCEST depletion experiments. Fluorescence-based studies also demonstrate that xenon binds into the cavity of the pillararene with an association constant of 4.6 × 103 M-1. These data indicate that the water-soluble pillararene is a potential scaffold for building contrast agents that can be detected by xenon-129 magnetic resonance imaging.
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Affiliation(s)
- P. U.
Ashvin I. Fernando
- Department
of Chemistry, University of Rhode Island, 140 Flagg Road, Kingston, Rhode Island 02881, United States
- U.S.
Army Corps of Engineers, Engineer Research and Development Center, 3909 Halls Ferry Road, Vicksburg, Mississippi 39180, United States
| | - Yurii Shepelytskyi
- Department
of Chemistry, Lakehead University, 955 Oliver Road, Thunder Bay, Ontario P7B 6V4, Canada
| | - Paul T. Cesana
- Department
of Chemistry, University of Rhode Island, 140 Flagg Road, Kingston, Rhode Island 02881, United States
| | - Alanna Wade
- Department
of Chemistry, Lakehead University, 955 Oliver Road, Thunder Bay, Ontario P7B 6V4, Canada
| | - Vira Grynko
- Department
of Chemistry, Lakehead University, 955 Oliver Road, Thunder Bay, Ontario P7B 6V4, Canada
| | - Adriana M. Mendieta
- Department
of Chemistry, University of Rhode Island, 140 Flagg Road, Kingston, Rhode Island 02881, United States
| | - Lauren E. Seveney
- Department
of Chemistry, University of Rhode Island, 140 Flagg Road, Kingston, Rhode Island 02881, United States
| | - Joseph D. Brown
- Department
of Chemistry, University of Rhode Island, 140 Flagg Road, Kingston, Rhode Island 02881, United States
- United
States Coast Guard Academy, 31 Mohegan Avenue, New London, Connecticut 06320, United States
| | - Francis T. Hane
- Thunder
Bay Regional Research Institute, 980 Oliver Road, Thunder
Bay, Ontario P7B 6V4, Canada
| | - Mitchell S. Albert
- Department
of Chemistry, Lakehead University, 955 Oliver Road, Thunder Bay, Ontario P7B 6V4, Canada
- Thunder
Bay Regional Research Institute, 980 Oliver Road, Thunder
Bay, Ontario P7B 6V4, Canada
| | - Brenton DeBoef
- Department
of Chemistry, University of Rhode Island, 140 Flagg Road, Kingston, Rhode Island 02881, United States
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7
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Abstract
Hyperpolarized noble gases have been used early on in applications for sensitivity enhanced NMR. 129Xe has been explored for various applications because it can be used beyond the gas-driven examination of void spaces. Its solubility in aqueous solutions and its affinity for hydrophobic binding pockets allows "functionalization" through combination with host structures that bind one or multiple gas atoms. Moreover, the transient nature of gas binding in such hosts allows the combination with another signal enhancement technique, namely chemical exchange saturation transfer (CEST). Different systems have been investigated for implementing various types of so-called Xe biosensors where the gas binds to a targeted host to address molecular markers or to sense biophysical parameters. This review summarizes developments in biosensor design and synthesis for achieving molecular sensing with NMR at unprecedented sensitivity. Aspects regarding Xe exchange kinetics and chemical engineering of various classes of hosts for an efficient build-up of the CEST effect will also be discussed as well as the cavity design of host molecules to identify a pool of bound Xe. The concept is presented in the broader context of reporter design with insights from other modalities that are helpful for advancing the field of Xe biosensors.
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Affiliation(s)
| | - Leif Schröder
- Molecular Imaging, Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), 13125 Berlin, Germany;
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8
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Abstract
We investigated Xe binding in a previously reported paramagnetic metal-organic tetrahedral capsule, [Co4L6]4-, where L2- = 4,4'-bis[(2-pyridinylmethylene)amino][1,1'-biphenyl]-2,2'-disulfonate. The Xe-inclusion complex, [XeCo4L6]4-, was confirmed by 1H NMR spectroscopy to be the dominant species in aqueous solution saturated with Xe gas. The measured Xe dissociation rate in [XeCo4L6]4-, koff = 4.45(5) × 102 s-1, was at least 40 times greater than that in the analogous [XeFe4L6]4- complex, highlighting the capability of metal-ligand interactions to tune the capsule size and guest permeability. The rapid exchange of 129Xe nuclei in [XeCo4L6]4- produced significant hyperpolarized 129Xe chemical exchange saturation transfer (hyper-CEST) NMR signal at 298 K, detected at a concentration of [XeCo4L6]4- as low as 100 pM, with presaturation at -89 ppm, which was referenced to solvated 129Xe in H2O. The saturation offset was highly temperature-dependent with a slope of -0.41(3) ppm/K, which is attributed to hyperfine interactions between the encapsulated 129Xe nucleus and electron spins on the four CoII centers. As such, [XeCo4L6]4- represents the first example of a paramagnetic hyper-CEST (paraHYPERCEST) sensor. Remarkably, the hyper-CEST 129Xe NMR resonance for [XeCo4L6]4- (δ = -89 ppm) was shifted 105 ppm upfield from the diamagnetic analogue [XeFe4L6]4- (δ = +16 ppm). The Xe inclusion complex was further characterized in the crystal structure of (C(NH2)3)4[Xe0.7Co4L6]·75 H2O (1). Hydrogen bonding between capsule-linker sulfonate groups and exogenous guanidinium cations, (C(NH2)3)+, stabilized capsule-capsule interactions in the solid state and also assisted in trapping a Xe atom (∼42 Å3) in the large (135 Å3) cavity of 1. Magnetic susceptibility measurements confirmed the presence of four noninteracting, magnetically anisotropic high-spin CoII centers in 1. Furthermore, [Co4L6]4- was found to be stable toward aggregation and oxidation, and the CEST performance of [XeCo4L6]4- was unaffected by biological macromolecules in H2O. These results recommend metal-organic capsules for fundamental investigations of Xe host-guest chemistry as well as applications with highly sensitive 129Xe-based sensors.
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9
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Chattaraj R, Hwang M, Zemerov SD, Dmochowski IJ, Hammer DA, Lee D, Sehgal CM. Ultrasound Responsive Noble Gas Microbubbles for Applications in Image-Guided Gas Delivery. Adv Healthc Mater 2020; 9:e1901721. [PMID: 32207250 PMCID: PMC7457952 DOI: 10.1002/adhm.201901721] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2019] [Revised: 02/13/2020] [Accepted: 02/21/2020] [Indexed: 12/18/2022]
Abstract
Noble gases, especially xenon (Xe), have been shown to have antiapoptotic effects in treating hypoxia ischemia related injuries. Currently, in vivo gas delivery is systemic and performed through inhalation, leading to reduced efficacy at the injury site. This report provides a first demonstration of the encapsulation of pure Xe, Ar, or He in phospholipid-coated sub-10 µm microbubbles, without the necessity of stabilizing perfluorocarbon additives. Optimization of shell compositions and preparation techniques show that distearoylphosphatidylcholine (DSPC) with DSPE-PEG5000 can produce stable microbubbles upon shaking, while dibehenoylphosphatidylcholine (DBPC) blended with either DSPE-PEG2000 or DSPE-PEG5000 produces a high yield of microbubbles via a sonication/centrifugation method. Xe and Ar concentrations released into the microbubble suspension headspace are measured using GC-MS, while Xe released directly in solution is detected by the fluorescence quenching of a Xe-sensitive cryptophane molecule. Bubble production is found to be amenable to scale-up while maintaining their size distribution and stability. Excellent ultrasound contrast is observed in a phantom for several minutes under physiological conditions, while an intravenous administration of a bolus of pure Xe microbubbles provides significant contrast in a mouse in pre- and post-lung settings (heart and kidney, respectively), paving the way for image-guided, localized gas delivery for theranostic applications.
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Affiliation(s)
- Rajarshi Chattaraj
- Department of Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Misun Hwang
- Department of Radiology, University of Pennsylvania Medical Center, Philadelphia, Pennsylvania 19104, United States; Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania 19104, United States
| | - Serge D. Zemerov
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Ivan J Dmochowski
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Daniel A. Hammer
- Department of Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Daeyeon Lee
- Department of Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Chandra M. Sehgal
- Department of Radiology, University of Pennsylvania Medical Center, Philadelphia, Pennsylvania 19104, United States
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10
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Jayapaul J, Schröder L. Nanoparticle-Based Contrast Agents for 129Xe HyperCEST NMR and MRI Applications. Contrast Media Mol Imaging 2019; 2019:9498173. [PMID: 31819739 PMCID: PMC6893250 DOI: 10.1155/2019/9498173] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Accepted: 10/15/2019] [Indexed: 02/06/2023]
Abstract
Spin hyperpolarization techniques have enabled important advancements in preclinical and clinical MRI applications to overcome the intrinsic low sensitivity of nuclear magnetic resonance. Functionalized xenon biosensors represent one of these approaches. They combine two amplification strategies, namely, spin exchange optical pumping (SEOP) and chemical exchange saturation transfer (CEST). The latter one requires host structures that reversibly bind the hyperpolarized noble gas. Different nanoparticle approaches have been implemented and have enabled molecular MRI with 129Xe at unprecedented sensitivity. This review gives an overview of the Xe biosensor concept, particularly how different nanoparticles address various critical aspects of gas binding and exchange, spectral dispersion for multiplexing, and targeted reporter delivery. As this concept is emerging into preclinical applications, comprehensive sensor design will be indispensable in translating the outstanding sensitivity potential into biomedical molecular imaging applications.
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Affiliation(s)
- Jabadurai Jayapaul
- Molecular Imaging, Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), 13125 Berlin, Germany
| | - Leif Schröder
- Molecular Imaging, Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), 13125 Berlin, Germany
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11
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Abstract
Xenon biosensors are an emerging tool for different molecular imaging approaches. For many applications, their development requires peptide synthesis steps, followed by the selective installation of a xenon host onto the peptide backbone in solution. In this study, three different strategies were attempted for generating entire Xe biosensors on the solid support. Notably, one strategy involving CryA-da was beneficial by directly integrating this host into the growing construct on a low loaded resin via modification of the administered subcomponent equivalents and by prolonging the coupling procedure. Subsequently, installation of additional amino acids or of additional labels onto the growing construct was achieved by a procedure in which an excess amine was administered to the activated CryA-da (acid) anchored onto the resin. Further, the as-generated Xe biosensor was tested for its NMR and MRI capabilities in H2O and compared to the performance of CryA-ma. Xe NMR of the biosensor indicated a clear CEST response and the Xe MR images revealed similar contrast compared to the reference host. These observations suggest that functionalizing CryA-da on both sides with multiple labels did not alter significantly its NMR capabilities. Hereby, we could show the successful and complete synthesis of a CryA-da-based xenon biosensor on the solid support without any notable side reactions and without the necessity of multiple purification steps.
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Affiliation(s)
- Jabadurai Jayapaul
- Molecular Imaging, Department of Structural Biology , Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP) , Robert-Rössle-Strasse 10 , 13125 Berlin , Germany
| | - Leif Schröder
- Molecular Imaging, Department of Structural Biology , Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP) , Robert-Rössle-Strasse 10 , 13125 Berlin , Germany
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12
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Schnurr M, Joseph R, Naugolny-Keisar A, Kaizerman-Kane D, Bogdanoff N, Schuenke P, Cohen Y, Schröder L. High Exchange Rate Complexes of 129 Xe with Water-Soluble Pillar[5]arenes for Adjustable Magnetization Transfer MRI. Chemphyschem 2018; 20:246-251. [PMID: 30079552 DOI: 10.1002/cphc.201800618] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Indexed: 01/16/2023]
Abstract
Macrocyclic host structures for generating transiently bound 129 Xe have been used in various ultra-sensitive NMR and MRI applications for molecular sensing of biochemical analytes. They are based on hyperpolarized nuclei chemical exchange saturation transfer (Hyper-CEST). Here, we tested a set of water-soluble pillar[5]arenes with different counterions in order to compare their potential contrast agent abilities with that of cryptophane-A (CrA), the most widely used host for such purposes. The exchange of Xe with such compounds was found to be sensitive to the type of ions present in solution and can be used for switchable magnetization transfer (MT) contrast that arises from off-resonant pre-saturation. We demonstrate that the adjustable MT magnitude depends on the interplay of saturation parameters and found that the optimum MT contrast surpasses the CrA CEST performance at moderate saturation power. Since modification of such water-soluble pillar[5]arenes is straightforward, these compounds can be considered a promising platform for designing various sensors that may complement the field of Xe HyperCEST-based biosensing MRI.
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Affiliation(s)
- Matthias Schnurr
- Molecular Imaging, Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Robert-Rössle-Str. 10, 13125, Berlin, Germany
| | - Roymon Joseph
- School of Chemistry, The Sackler Faculty of Exact Sciences, Tel Aviv University, Ramat Aviv, Tel Aviv, 69978, Israel
| | - Alissa Naugolny-Keisar
- School of Chemistry, The Sackler Faculty of Exact Sciences, Tel Aviv University, Ramat Aviv, Tel Aviv, 69978, Israel
| | - Dana Kaizerman-Kane
- School of Chemistry, The Sackler Faculty of Exact Sciences, Tel Aviv University, Ramat Aviv, Tel Aviv, 69978, Israel
| | - Nils Bogdanoff
- Molecular Imaging, Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Robert-Rössle-Str. 10, 13125, Berlin, Germany
| | - Patrick Schuenke
- Molecular Imaging, Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Robert-Rössle-Str. 10, 13125, Berlin, Germany
| | - Yoram Cohen
- School of Chemistry, The Sackler Faculty of Exact Sciences, Tel Aviv University, Ramat Aviv, Tel Aviv, 69978, Israel
| | - Leif Schröder
- Molecular Imaging, Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Robert-Rössle-Str. 10, 13125, Berlin, Germany
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