1
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Huang Y, Chen X, Zhu Z, Mukherjee A. A Dual-Gene Reporter-Amplifier Architecture for Enhancing the Sensitivity of Molecular MRI by Water Exchange. Chembiochem 2024; 25:e202400087. [PMID: 38439618 DOI: 10.1002/cbic.202400087] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2024] [Revised: 03/04/2024] [Accepted: 03/05/2024] [Indexed: 03/06/2024]
Abstract
The development of genetic reporters for magnetic resonance imaging (MRI) is essential for investigating biological functions in vivo. However, current MRI reporters have low sensitivity, making it challenging to create significant contrast against the tissue background, especially when only a small fraction of cells express the reporter. To overcome this limitation, we developed an approach for amplifying the sensitivity of molecular MRI by combining a chemogenetic contrast mechanism with a biophysical approach to increase water diffusion through the co-expression of a dual-gene construct comprising an organic anion transporting polypeptide, Oatp1b3, and a water channel, Aqp1. We first show that the expression of Aqp1 amplifies MRI contrast in cultured cells engineered to express Oatp1b3. We demonstrate that the contrast amplification is caused by Aqp1-driven increase in water exchange, which provides the gadolinium ions internalized by Oatp1b3-expressing cells with access to a larger water pool compared with exchange-limited conditions. We further show that our methodology allows cells to be detected using approximately 10-fold lower concentrations of gadolinium than that in the Aqp1-free scenario. Finally, we show that our approach enables the imaging of mixed-cell cultures containing a low fraction of Oatp1b3-labeled cells that are undetectable on the basis of Oatp1b3 expression alone.
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Affiliation(s)
- Yimeng Huang
- Department of Chemistry, University of California, Santa Barbara, CA 93106-5080
| | - Xinyue Chen
- Department of Molecular, Cellular, and Developmental Biology, University of California, Santa Barbara, CA 93106-5080
| | - Ziyue Zhu
- Department of Molecular, Cellular, and Developmental Biology, University of California, Santa Barbara, CA 93106-5080
| | - Arnab Mukherjee
- Department of Chemistry, University of California, Santa Barbara, CA 93106-5080
- Department of Molecular, Cellular, and Developmental Biology, University of California, Santa Barbara, CA 93106-5080
- Department of Chemical Engineering, University of California, Santa Barbara, CA 93106-5080
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2
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Jian CB, Wu YY, Lin MH, Gao HD, Chen CY, Leong SK, Tzou DLM, Hwang DW, Lee HM. A Facile NMR Method for Pre-MRI Evaluation of Trigger-Responsive T 1 Contrast Enhancement. SMALL METHODS 2024:e2301603. [PMID: 38459640 DOI: 10.1002/smtd.202301603] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Revised: 02/09/2024] [Indexed: 03/10/2024]
Abstract
There is a growing interest in developing paramagnetic nanoparticles as responsive magnetic resonance imaging (MRI) contrast agents, which feature switchable T1 image contrast of water protons upon biochemical cues for better discerning diseases. However, performing an MRI is pragmatically limited by its cost and availability. Hence, a facile, routine method for measuring the T1 contrast is highly desired in early-stage development. This work presents a single-point inversion recovery (IR) nuclear magnetic resonance (NMR) method that can rapidly evaluate T1 contrast change by employing a single, optimized IR pulse sequence that minimizes water signal for "off-state" nanoparticles and allows for sensitively measuring the signal change with "switch-on" T1 contrast. Using peptide-induced liposomal gadopentetic acid (Gd3+ -DTPA) release and redox-sensitive manganese oxide (MnO2 ) nanoparticles as a demonstration of generality, this method successfully evaluates the T1 shortening of water protons caused by liposomal Gd3+ -DTPA release and Mn2+ formation from MnO2 reduction. Furthermore, the NMR measurement is highly correlated to T1 -weighted MRI scans, suggesting its feasibility to predict the MRI results at the same field strength. This NMR method can be a low-cost, time-saving alternative for pre-MRI evaluation for a diversity of responsive T1 contrast systems.
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Affiliation(s)
- Cheng-Bang Jian
- Institute of Chemistry, Academia Sinica, Taipei, 11529, Taiwan
- Nano Science and Technology Program, Taiwan International Graduate Program, Academia Sinica and National Taiwan University, Taipei, 11529, Taiwan
- Department of Chemistry, National Taiwan University, Taipei, 10617, Taiwan
| | - Ying-Yann Wu
- Institute of Chemistry, Academia Sinica, Taipei, 11529, Taiwan
| | - Ming-Huang Lin
- Institute of Biomedical Sciences, Academia Sinica, Taipei, 11529, Taiwan
| | - Hua-De Gao
- Institute of Chemistry, Academia Sinica, Taipei, 11529, Taiwan
| | - Chong-Yan Chen
- Institute of Chemistry, Academia Sinica, Taipei, 11529, Taiwan
| | - Shwee Khuan Leong
- Institute of Chemistry, Academia Sinica, Taipei, 11529, Taiwan
- Sustainable Chemical Science and Technology Program, Taiwan International Graduate Program, Academia Sinica and National Yang Ming Chiao Tung University, Taipei, 11529, Taiwan
- Department of Applied Chemistry, National Yang Ming Chiao Tung University, Hsinchu, 30093, Taiwan
| | - Der-Lii M Tzou
- Institute of Chemistry, Academia Sinica, Taipei, 11529, Taiwan
| | - Dennis W Hwang
- Institute of Biomedical Sciences, Academia Sinica, Taipei, 11529, Taiwan
| | - Hsien-Ming Lee
- Institute of Chemistry, Academia Sinica, Taipei, 11529, Taiwan
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3
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Simon J, Schwalm M, Morstein J, Trauner D, Jasanoff A. Mapping light distribution in tissue by using MRI-detectable photosensitive liposomes. Nat Biomed Eng 2023; 7:313-322. [PMID: 36550300 DOI: 10.1038/s41551-022-00982-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Accepted: 11/04/2022] [Indexed: 12/24/2022]
Abstract
Characterizing sources and targets of illumination in living tissue is challenging. Here we show that spatial distributions of light in tissue can be mapped by using magnetic resonance imaging (MRI) in the presence of photosensitive nanoparticle probes. Each probe consists of a reservoir of paramagnetic molecules enclosed by a liposomal membrane incorporating photosensitive lipids. Incident light causes the photoisomerization of the lipids and alters hydrodynamic exchange across the membrane, thereby affecting longitudinal relaxation-weighted contrast in MRI. We injected the nanoparticles into the brains of live rats and used MRI to map responses to illumination profiles characteristic of widely used applications of photostimulation, photometry and phototherapy. The responses deviated from simple photon propagation models and revealed signatures of light scattering and nonlinear responsiveness. Paramagnetic liposomal nanoparticles may enable MRI to map a broad range of optical phenomena in deep tissue and other opaque environments.
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Affiliation(s)
- Jacob Simon
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Miriam Schwalm
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | | | - Dirk Trauner
- Department of Chemistry, New York University, New York, NY, USA
| | - Alan Jasanoff
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA.
- Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA.
- Department of Nuclear Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA.
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4
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Geng W, Zheng Z, Guo D. Supramolecular design based activatable magnetic resonance imaging. VIEW 2020. [DOI: 10.1002/viw.20200059] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Affiliation(s)
- Wen‐Chao Geng
- College of Chemistry Key Laboratory of Functional Polymer Materials (Ministry of Education) State Key Laboratory of Elemento‐Organic Chemistry Nankai University Tianjin P. R. China
| | - Zhe Zheng
- College of Chemistry Key Laboratory of Functional Polymer Materials (Ministry of Education) State Key Laboratory of Elemento‐Organic Chemistry Nankai University Tianjin P. R. China
| | - Dong‐Sheng Guo
- College of Chemistry Key Laboratory of Functional Polymer Materials (Ministry of Education) State Key Laboratory of Elemento‐Organic Chemistry Nankai University Tianjin P. R. China
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5
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Mulas G, Rolla GA, Geraldes CFGC, Starmans LWE, Botta M, Terreno E, Tei L. Mn(II)-Based Lipidic Nanovesicles as High-Efficiency MRI Probes. ACS APPLIED BIO MATERIALS 2020; 3:2401-2409. [PMID: 35025289 DOI: 10.1021/acsabm.0c00138] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Although nowadays there is a renewed and growing interest in Mn-based contrast agents, there are only few studies dealing with Mn-based lipophilic nanoparticles and how they may be optimized as MRI contrast agents. Three amphiphilic paramagnetic Mn(II) complexes based on derivatives of EDTA and 1,4-DO2A were used for the preparation of lipidic nanoparticles. The length and position of the aliphatic chains were found to control whether either vesicular liposomes, nonvesicular bicelles, or a mixture of both was produced as well as the size and morphology of phospholipid-based self-assembling nanoaggregates. These differences determine whether hydrophilic Gd-based contrast agents or fluorescent dyes can be entrapped in the aqueous core of the nanoaggregate. Structural characterization was performed by cryo-TEM. Detailed 1H NMR relaxometric analyses were carried out on all systems. The effect of entrapping gadoteridol in the aqueous core (where present) was studied by preparing diamagnetic amphiphilic Zn(II) analogues. In the case of homogeneous systems, the data were also fitted to obtain the relaxometric parameters for comparison with literature data. The results of these studies demonstrate enhanced relaxivity of the nanoaggregates with respect to monomeric analogues. This work allowed us to understand how to control the formation of different types of nanovesicles (liposomes, bicelles, and micelles), optimize their MRI contrast, and provide different in vivo biodistribution characteristics.
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Affiliation(s)
- Gilberto Mulas
- Centro di Imaging Molecolare e Preclinico, Dipartimento di Biotecnologie Molecolari e Scienze della Salute, Università di Torino, Via Nizza 52, 10126 Torino, Italy
| | - Gabriele A Rolla
- Dipartimento di Scienze ed Innovazione Tecnologica, Università del Piemonte Orientale, Viale T. Michel 11, Alessandria 15121, Italy
| | - Carlos F G C Geraldes
- Department of Life Sciences and Coimbra Chemistry Center, Faculty of Science and Technology, University of Coimbra, 3000-393 Coimbra, Portugal.,CIBIT/ICNAS-Instituto de Ciências Nucleares Aplicadas à Sau'de, Po'lo das Ciências da Sau'de, Azinhaga de Santa Comba, 3000-548 Coimbra, Portugal
| | - Lucas W E Starmans
- Biomedical Engineering, Eindhoven University of Technology, 5656 AE Eindhoven, The Netherlands
| | - Mauro Botta
- Dipartimento di Scienze ed Innovazione Tecnologica, Università del Piemonte Orientale, Viale T. Michel 11, Alessandria 15121, Italy
| | - Enzo Terreno
- Centro di Imaging Molecolare e Preclinico, Dipartimento di Biotecnologie Molecolari e Scienze della Salute, Università di Torino, Via Nizza 52, 10126 Torino, Italy
| | - Lorenzo Tei
- Dipartimento di Scienze ed Innovazione Tecnologica, Università del Piemonte Orientale, Viale T. Michel 11, Alessandria 15121, Italy
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6
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Palaiokostas M, Ding W, Shahane G, Orsi M. Effects of lipid composition on membrane permeation. SOFT MATTER 2018; 14:8496-8508. [PMID: 30346462 DOI: 10.1039/c8sm01262h] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Passive permeation through lipid membranes is an essential process in biology. In vivo membranes typically consist of mixtures of lamellar and nonlamellar lipids. Lamellar lipids are characterized by their tendency to form lamellar sheet-like structures, which are predominant in nature. Nonlamellar lipids, when isolated, instead form more geometrically complex nonlamellar phases. While mixed lamellar/nonlamellar lipid membranes tend to adopt the ubiquitous lamellar bilayer structure, the presence of nonlamellar lipids is known to have profound effects on key membrane properties, such as internal distributions of stress and elastic properties, which in turn may alter related biological processes. This work focuses on one such process, i.e., permeation, by utilising atomistic molecular dynamics simulations in order to obtain transfer free energy profiles, diffusion profiles and permeation coefficients for a series of thirteen small molecules and drugs. Each permeant is tested on two bilayer membranes of different lipid composition, i.e., purely lamellar and mixed lamellar/nonlamellar. Our results indicate that the presence of nonlamellar lipids reduces permeation for smaller molecules (molecular weight < 100) but facilitates it for the largest ones (molecular weight > 100). This work represents an advancement towards the development of more realistic in silico permeability assays, which may have a substantial future impact in the area of rational drug design.
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Affiliation(s)
- Michail Palaiokostas
- School of Engineering and Materials Science, Queen Mary University of London, London, UK
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7
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Skupin-Mrugalska P, Sobotta L, Warowicka A, Wereszczynska B, Zalewski T, Gierlich P, Jarek M, Nowaczyk G, Kempka M, Gapinski J, Jurga S, Mielcarek J. Theranostic liposomes as a bimodal carrier for magnetic resonance imaging contrast agent and photosensitizer. J Inorg Biochem 2018; 180:1-14. [DOI: 10.1016/j.jinorgbio.2017.11.025] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Revised: 11/03/2017] [Accepted: 11/27/2017] [Indexed: 01/17/2023]
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8
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Chipot C, Comer J. Subdiffusion in Membrane Permeation of Small Molecules. Sci Rep 2016; 6:35913. [PMID: 27805049 PMCID: PMC5090971 DOI: 10.1038/srep35913] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2016] [Accepted: 10/05/2016] [Indexed: 12/22/2022] Open
Abstract
Within the solubility-diffusion model of passive membrane permeation of small molecules, translocation of the permeant across the biological membrane is traditionally assumed to obey the Smoluchowski diffusion equation, which is germane for classical diffusion on an inhomogeneous free-energy and diffusivity landscape. This equation, however, cannot accommodate subdiffusive regimes, which have long been recognized in lipid bilayer dynamics, notably in the lateral diffusion of individual lipids. Through extensive biased and unbiased molecular dynamics simulations, we show that one-dimensional translocation of methanol across a pure lipid membrane remains subdiffusive on timescales approaching typical permeation times. Analysis of permeant motion within the lipid bilayer reveals that, in the absence of a net force, the mean squared displacement depends on time as t0.7, in stark contrast with the conventional model, which assumes a strictly linear dependence. We further show that an alternate model using a fractional-derivative generalization of the Smoluchowski equation provides a rigorous framework for describing the motion of the permeant molecule on the pico- to nanosecond timescale. The observed subdiffusive behavior appears to emerge from a crossover between small-scale rattling of the permeant around its present position in the membrane and larger-scale displacements precipitated by the formation of transient voids.
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Affiliation(s)
- Christophe Chipot
- Laboratoire International Associé Centre National de la Recherche Scientifique et University of Illinois at Urbana-Champaign, Unité Mixte de Recherche n°7565, Université de Lorraine, B.P. 70239, 54506, Vandœuvre-lès-Nancy cedex, France
- Theoretical and Computational Biophysics Group, Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, 405 North Mathews Avenue, Urbana, Illinois 61801, USA
- Department of Physics, University of Illinois at Urbana-Champaign, 1110 West Green Street, Urbana, Illinois 61801, USA
| | - Jeffrey Comer
- Institute of Computational Comparative Medicine, Nanotechnology Innovation Center of Kansas State, Department of Anatomy and Physiology, 1800 Denison Ave, Kansas State University, Manhattan, Kansas 66506, USA
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9
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Iron(III)-Based Magnetic Resonance–Imageable Liposomal T1 Contrast Agent for Monitoring Temperature-Induced Image-Guided Drug Delivery. Invest Radiol 2016; 51:735-745. [DOI: 10.1097/rli.0000000000000297] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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10
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Comer J, Schulten K, Chipot C. Calculation of Lipid-Bilayer Permeabilities Using an Average Force. J Chem Theory Comput 2015; 10:554-64. [PMID: 26580032 DOI: 10.1021/ct400925s] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Calculations of lipid bilayer permeabilities from first principles, using molecular simulations, would be valuable to rapidly assess the bioavailability of drug candidates, as well as to decipher, at the atomic level, the mechanisms that underlie the translocation of permeants. The most common theoretical approach, the solubility-diffusion model, requires determination of the free energy and the diffusivity as functions of the position of the permeant. Quantitative predictions of permeability have, however, been stymied by acute difficulties in calculating the diffusivity, inadequate sampling, and, most insidiously, systematic biases due to imperfections in the force field, simulation parameters, and the inherent limitations of the diffusive model. In the present work, we combine importance-sampling simulations employing an adaptive biasing force with a Bayesian-inference algorithm to determine the free energy and diffusivity with noteworthy precision and spatial resolution. In multimicrosecond simulations, we probe the sensitivity of the permeability estimates to different aspects of the methodology, including the truncation of short-range interactions, the thermostat, the force-field parameters of the permeant, the time scale over which the diffusivity is estimated, and the size of the simulated system. The force-field parameters and time scale dependence of the diffusivities impose the greatest uncertainties on the permeability estimates. Our simulations highlight the importance of membrane distortion due to the presence of the permeant, which may be partially suppressed if the bilayer patch is not large enough. We suggest that improvements to force fields and more robust kinetic models may be needed to reduce systematic errors below a factor of two.
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Affiliation(s)
- Jeffrey Comer
- Laboratoire International Associé, Centre National de la Recherche Scientifique et University of Illinois at Urbana-Champaign , Unité Mixte de Recherche n°7565, Université de Lorraine , B.P. 70239 54506 Vandœuvre-lès-Nancy cedex, France
| | - Klaus Schulten
- Department of Physics, University of Illinois at Urbana-Champaign , 1110 West Green Street, Urbana, Illinois 61801, United States.,Theoretical and Computational Biophysics Group, Beckman Institute for Advanced Science and Engineering, University of Illinois at Urbana-Champaign , 405 North Mathews, Urbana, Illinois 61801, United States
| | - Christophe Chipot
- Laboratoire International Associé, Centre National de la Recherche Scientifique et University of Illinois at Urbana-Champaign , Unité Mixte de Recherche n°7565, Université de Lorraine , B.P. 70239 54506 Vandœuvre-lès-Nancy cedex, France.,Theoretical and Computational Biophysics Group, Beckman Institute for Advanced Science and Engineering, University of Illinois at Urbana-Champaign , 405 North Mathews, Urbana, Illinois 61801, United States
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11
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Kuijten MMP, Hannah Degeling M, Chen JW, Wojtkiewicz G, Waterman P, Weissleder R, Azzi J, Nicolay K, Tannous BA. Multimodal targeted high relaxivity thermosensitive liposome for in vivo imaging. Sci Rep 2015; 5:17220. [PMID: 26610702 PMCID: PMC4661695 DOI: 10.1038/srep17220] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2015] [Accepted: 10/27/2015] [Indexed: 11/19/2022] Open
Abstract
Liposomes are spherical, self-closed structures formed by lipid bilayers that can encapsulate drugs and/or imaging agents in their hydrophilic core or within their membrane moiety, making them suitable delivery vehicles. We have synthesized a new liposome containing gadolinium-DOTA lipid bilayer, as a targeting multimodal molecular imaging agent for magnetic resonance and optical imaging. We showed that this liposome has a much higher molar relaxivities r1 and r2 compared to a more conventional liposome containing gadolinium-DTPA-BSA lipid. By incorporating both gadolinium and rhodamine in the lipid bilayer as well as biotin on its surface, we used this agent for multimodal imaging and targeting of tumors through the strong biotin-streptavidin interaction. Since this new liposome is thermosensitive, it can be used for ultrasound-mediated drug delivery at specific sites, such as tumors, and can be guided by magnetic resonance imaging.
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Affiliation(s)
- Maayke M. P. Kuijten
- Experimental Therapeutics and Molecular Imaging Laboratory, Neuroscience Center, Massachusetts General Hospital, Boston, MA 02114 USA
- Program in Neuroscience, Harvard Medical School, Boston, MA 02114 USA
- Department of Biomedical Engineering, Biomedical NMR, Eindhoven University of Technology, Eindhoven, the Netherlands
| | - M. Hannah Degeling
- Experimental Therapeutics and Molecular Imaging Laboratory, Neuroscience Center, Massachusetts General Hospital, Boston, MA 02114 USA
- Program in Neuroscience, Harvard Medical School, Boston, MA 02114 USA
- Department of Neurosurgery, Leiden University Medical Center, Leiden, the Netherlands
| | - John W. Chen
- Division of Neuroradiology, Department of Radiology, Massachusetts General Hospital, Boston, MA 02114 USA
- Center for Systems Biology, Massachusetts General Hospital, Boston, MA 02114 USA
| | - Gregory Wojtkiewicz
- Center for Systems Biology, Massachusetts General Hospital, Boston, MA 02114 USA
| | - Peter Waterman
- Center for Systems Biology, Massachusetts General Hospital, Boston, MA 02114 USA
| | - Ralph Weissleder
- Center for Systems Biology, Massachusetts General Hospital, Boston, MA 02114 USA
| | - Jamil Azzi
- Transplantation Research Center, Renal Division, Brigham and Women’s Hospital and Children’s Hospital, Harvard Medical School, Boston, Boston, MA 02114 USA
| | - Klaas Nicolay
- Department of Biomedical Engineering, Biomedical NMR, Eindhoven University of Technology, Eindhoven, the Netherlands
| | - Bakhos A. Tannous
- Experimental Therapeutics and Molecular Imaging Laboratory, Neuroscience Center, Massachusetts General Hospital, Boston, MA 02114 USA
- Program in Neuroscience, Harvard Medical School, Boston, MA 02114 USA
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12
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Guenoun J, Doeswijk GN, Krestin GP, Bernsen MR. Compartmentalization of Gd liposomes: the quenching effect explained. CONTRAST MEDIA & MOLECULAR IMAGING 2015; 11:106-14. [PMID: 26463264 DOI: 10.1002/cmmi.1669] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2015] [Revised: 07/09/2015] [Accepted: 08/18/2015] [Indexed: 11/09/2022]
Abstract
Cationic liposomes carrying high [Gd] can be used as efficient cell-labeling agents. In a compartmentalized state, Gd can cause signal loss (relaxivity quenching). The contributions of liposomal [Gd], size and compartmentalization state to relaxivity quenching were assessed. The dependency of signal intensity (SI) on intraliposomal [Gd] was assessed comparing three different [Gd] (0.3, 0.6 and 1.0 M Gd) in both small (80 nm) and large (120 nm) cationic liposomes. In addition, five compartmentalization states were compared: free Gd, intact Gd liposomes, ruptured Gd liposomes, Gd liposomes in intact cells and Gd liposomes in ruptured cells (simulating cell death). Gd also causes R2 effects, which is often overlooked. Therefore, both R1 and R2 relaxation rates of a dilution range were measured by T1 and T2 mapping on a 7 T clinical scanner. Less is more. As the unidirectional water efflux rate (outbound across the liposome membrane, κle) is proportional to the surface:volume ratio, smaller liposomes yielded a consistently higher R1 than larger liposomes. For equal voxel [Gd] less concentrated liposomes (0.3 M Gd) yielded higher R1/R2 ratio because of the higher extraliposomal water fraction (vl ). Gd exhibits a dualistic behavior: from hypointensity to hyperintensity to hypointensity, with decreasing [Gd]. Regarding compartmentalization, fewer membrane barriers means a higher R1 /R2 ratio. Gd liposomes exhibit a versatile contrast behavior, dependent on the compartmentalization state, liposomal size, intraliposomal [Gd] and liposome number. Both R1 and R2 effects contribute to this. The versatility allows one to tailor the optimal liposomal formulation to desired goals in cell labeling and tracking.
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Affiliation(s)
- Jamal Guenoun
- Department of Radiology, Erasmus MC - University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Gabriela N Doeswijk
- Department of Radiology, Erasmus MC - University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Gabriel P Krestin
- Department of Radiology, Erasmus MC - University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Monique R Bernsen
- Department of Radiology, Erasmus MC - University Medical Center Rotterdam, Rotterdam, The Netherlands.,Department of Nuclear Medicine, Erasmus MC - University Medical Center Rotterdam, Rotterdam, The Netherlands
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13
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Yeo SY, de Smet M, Langereis S, Vander Elst L, Muller RN, Grüll H. Temperature-sensitive paramagnetic liposomes for image-guided drug delivery: Mn2+ versus [Gd(HPDO3A)(H2O)]. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2014; 1838:2807-16. [DOI: 10.1016/j.bbamem.2014.07.019] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2014] [Revised: 06/29/2014] [Accepted: 07/15/2014] [Indexed: 01/08/2023]
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14
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Magnetic resonance guided high-intensity focused ultrasound for image-guided temperature-induced drug delivery. Adv Drug Deliv Rev 2014; 72:65-81. [PMID: 24463345 DOI: 10.1016/j.addr.2014.01.006] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2013] [Revised: 01/08/2014] [Accepted: 01/14/2014] [Indexed: 12/29/2022]
Abstract
Magnetic resonance guided high-intensity focused ultrasound (MR-HIFU) is a versatile technology platform for noninvasive thermal therapies in oncology. Since MR-HIFU allows heating of deep-seated tissue to well-defined temperatures under MR image guidance, this novel technology has great potential for local heat-mediated drug delivery from temperature-sensitive liposomes (TSLs). In particular, MR provides the ability for image guidance of the drug delivery when an MRI contrast agent is co-encapsulated with the drug in the aqueous lumen of the liposomes. Monitoring of the tumor drug coverage offers possibilities for a personalized thermal treatment in oncology. This review focuses on MR-HIFU as a noninvasive technology platform, temperature-sensitive liposomal formulations for drug delivery and image-guided drug delivery, and the effect of HIFU-induced hyperthermia on the TSL and drug distribution. Finally, the opportunities and challenges of localized MR-HIFU-mediated drug delivery from temperature-sensitive liposomes in oncology are discussed.
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15
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Bruckman MA, Yu X, Steinmetz NF. Engineering Gd-loaded nanoparticles to enhance MRI sensitivity via T(1) shortening. NANOTECHNOLOGY 2013; 24:462001. [PMID: 24158750 PMCID: PMC3895399 DOI: 10.1088/0957-4484/24/46/462001] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Magnetic resonance imaging (MRI) is a noninvasive imaging technique capable of obtaining high-resolution anatomical images of the body. Major drawbacks of MRI are the low contrast agent sensitivity and inability to distinguish healthy tissue from diseased tissue, making early detection challenging. To address this technological hurdle, paramagnetic contrast agents have been developed to increase the longitudinal relaxivity, leading to an increased signal-to-noise ratio. This review focuses on methods and principles that enabled the design and engineering of nanoparticles to deliver contrast agents with enhanced ionic relaxivities. Different engineering strategies and nanoparticle platforms will be compared in terms of their manufacturability, biocompatibility properties, and their overall potential to make an impact in clinical MR imaging.
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Affiliation(s)
- Michael A. Bruckman
- Department of Biomedical Engineering, Case Western Reserve University, School of Medicine, 10900 Euclid Avenue, Cleveland, OH 44106, USA
| | - Xin Yu
- Department of Biomedical Engineering, Case Western Reserve University, School of Medicine, 10900 Euclid Avenue, Cleveland, OH 44106, USA
- Department of Radiology, Case Western Reserve University, School of Medicine, 10900 Euclid Avenue, Cleveland, OH 44106, USA
| | - Nicole F. Steinmetz
- Department of Biomedical Engineering, Case Western Reserve University, School of Medicine, 10900 Euclid Avenue, Cleveland, OH 44106, USA
- Department of Radiology, Case Western Reserve University, School of Medicine, 10900 Euclid Avenue, Cleveland, OH 44106, USA
- Department of Materials Science and Engineering, Case Western Reserve University, School of Medicine, 10900 Euclid Avenue, Cleveland, OH 44106, USA
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Beebo A, Mathai JC, Schoefs B, Spetea C. Assessment of the requirement for aquaporins in the thylakoid membrane of plant chloroplasts to sustain photosynthetic water oxidation. FEBS Lett 2013; 587:2083-9. [PMID: 23732702 DOI: 10.1016/j.febslet.2013.05.046] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2013] [Revised: 04/30/2013] [Accepted: 05/16/2013] [Indexed: 11/18/2022]
Abstract
Oxygenic photosynthetic organisms use sunlight energy to oxidize water to molecular oxygen. This process is mediated by the photosystem II complex at the lumenal side of the thylakoid membrane. Most research efforts have been dedicated to understanding the mechanism behind the unique water oxidation reactions, whereas the delivery pathways for water molecules into the thylakoid lumen have not yet been studied. The most common mechanisms for water transport are simple diffusion and diffusion facilitated by specialized channel proteins named aquaporins. Calculations using published data for plant chloroplasts indicate that aquaporins are not necessary to sustain water supply into the thylakoid lumen at steady state photosynthetic rates. Yet, arguments for their presence in the plant thylakoid membrane and beneficial action are presented.
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Affiliation(s)
- Azeez Beebo
- Department of Biological and Environmental Sciences, University of Gothenburg, Box 461, 405 30 Gothenburg, Sweden
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17
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Ye F, Laurent S, Fornara A, Astolfi L, Qin J, Roch A, Martini A, Toprak MS, Muller RN, Muhammed M. Uniform mesoporous silica coated iron oxide nanoparticles as a highly efficient, nontoxic MRI T(2) contrast agent with tunable proton relaxivities. CONTRAST MEDIA & MOLECULAR IMAGING 2013; 7:460-8. [PMID: 22821880 DOI: 10.1002/cmmi.1473] [Citation(s) in RCA: 101] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Monodisperse mesoporous silica (mSiO(2) ) coated superparamagnetic iron oxide (Fe(3) O(4) @mSiO(2) ) nanoparticles (NPs) have been developed as a potential magnetic resonance imaging (MRI) T(2) contrast agent. To evaluate the effect of surface coating on MRI contrast efficiency, we examined the proton relaxivities of Fe(3) O(4) @mSiO(2) NPs with different coating thicknesses. It was found that the mSiO(2) coating has a significant impact on the efficiency of Fe(3) O(4) NPs for MRI contrast enhancement. The efficiency increases with the thickness of mSiO(2) coating and is much higher than that of the commercial contrast agents. Nuclear magnetic resonance (NMR) relaxometry of Fe(3) O(4) @mSiO(2) further revealed that mSiO(2) coating is partially permeable to water molecules and therefore induces the decrease of longitudinal relaxivity, r(1) . Biocompatibility evaluation of various sized (ca. 35-95 nm) Fe(3) O(4) @mSiO(2) NPs was tested on OC-k3 cells and the result showed that these particles have no negative impact on cell viability. The enhanced MRI efficiency of Fe(3) O(4) @mSiO(2) highlights these core-shell particles as highly efficient T(2) contrast agents with high biocompatibility.
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Affiliation(s)
- Fei Ye
- Functional Materials Division, Royal Institute of Technology (KTH), Electrum 229, 164 40, Kista, Stockholm, Sweden.
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18
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Hossann M, Wang T, Syunyaeva Z, Wiggenhorn M, Zengerle A, Issels RD, Reiser M, Lindner LH, Peller M. Non-ionic Gd-based MRI contrast agents are optimal for encapsulation into phosphatidyldiglycerol-based thermosensitive liposomes. J Control Release 2013; 166:22-9. [DOI: 10.1016/j.jconrel.2012.12.003] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2012] [Revised: 11/30/2012] [Accepted: 12/04/2012] [Indexed: 11/30/2022]
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19
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Satoh K, Seo Y, Matsuo S, Karabasil MR, Matsuki-Fukushima M, Nakahari T, Hosoi K. Roles of AQP5/AQP5-G103D in carbamylcholine-induced volume decrease and in reduction of the activation energy for water transport by rat parotid acinar cells. Pflugers Arch 2012; 464:375-89. [PMID: 22903161 DOI: 10.1007/s00424-012-1141-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2012] [Revised: 07/10/2012] [Accepted: 07/25/2012] [Indexed: 01/26/2023]
Abstract
In order to assess the contribution of the water channel aquaporin-5 (AQP5) to water transport by salivary gland acinar cells, we measured the cell volume and activation energy (E (a)) of diffusive water permeability in isolated parotid acinar cells obtained from AQP5-G103D mutant and their wild-type rats. Immunohistochemistry showed that there was no change induced by carbamylcholine (CCh; 1 μM) in the AQP5 detected in the acinar cells in the wild-type rat. Acinar cells from mutant rats, producing low levels of AQP5 in the apical membrane, showed a minimal increase in the AQP5 due to the CCh. In the wild-type rat, CCh caused a transient swelling of the acinus, followed by a rapid agonist-induced cell shrinkage, reaching a plateau at 30 s. In the mutant rat, the acinus did not swell by CCh challenge, and the agonist-induced cell shrinkage was delayed by 8 s, reaching a transient minimum at around 1 min, and recovered spontaneously even though CCh was persistently present. In the unstimulated wild-type acinar cells, E (a) was 3.4 ± 0.6 kcal mol(-1) and showed no detectable change after CCh stimulation. In the unstimulated mutant acinar cells, high E (a) value (5.9 ± 0.1 kcal mol(-1)) was detected and showed a minimal decrease after CCh stimulation (5.0 ± 0.3 kcal mol(-1)). These results suggested that AQP5 was the main pathway for water transport in the acinar cells and that it was responsible for the rapid agonist-induced acinar cell shrinkage and also necessary to keep the acinar cell volume reduced during the steady secretion in the wild-type rat.
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Affiliation(s)
- Keitaro Satoh
- Department of Regulatory Physiology, Dokkyo Medical University School of Medicine, 880 Kitakobayashi, Mibu-machi, Shimotsuga-gun, Tochigi, 321-0293, Japan.
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20
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Liu Y, Zhang N. Gadolinium loaded nanoparticles in theranostic magnetic resonance imaging. Biomaterials 2012; 33:5363-75. [DOI: 10.1016/j.biomaterials.2012.03.084] [Citation(s) in RCA: 121] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2012] [Accepted: 03/25/2012] [Indexed: 12/15/2022]
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21
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Gianolio E, Porto S, Napolitano R, Baroni S, Giovenzana GB, Aime S. Relaxometric investigations and MRI evaluation of a liposome-loaded pH-responsive gadolinium(III) complex. Inorg Chem 2012; 51:7210-7. [PMID: 22716284 DOI: 10.1021/ic300447n] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Accurate measurement of the tissue pH in vivo by MRI may be of clinical value for both diagnosis and selection/monitoring of therapy. To act as pH reporters, MRI contrast agents have to provide responsiveness to pH that does not require prior knowledge of the actual concentration of the contrast agent. This work deals with the use of a paramagnetic gadolinium(III) complex, loaded into liposomes, whose relaxometric properties are affected by the pH of the medium. In this system, the amphiphilic metal complex, which contains a moiety whose protonation changes the coordination properties of the metal chelate, experiences a different intraliposomial distribution depending on the pH conditions. The pH of the solution can be unambiguously identified by exploiting the peculiar characteristics of the resulting NMRD profiles, and a ratiometric pH-responsive method has been set up by comparing the relaxation enhancement at different magnetic field strengths.
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Affiliation(s)
- E Gianolio
- Department of Chemistry & Molecular Imaging Center, University of Torino, Via Nizza 52, Torino, Italy
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22
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Negussie AH, Yarmolenko PS, Partanen A, Ranjan A, Jacobs G, Woods D, Bryant H, Thomasson D, Dewhirst MW, Wood BJ, Dreher MR. Formulation and characterisation of magnetic resonance imageable thermally sensitive liposomes for use with magnetic resonance-guided high intensity focused ultrasound. Int J Hyperthermia 2011; 27:140-55. [PMID: 21314334 DOI: 10.3109/02656736.2010.528140] [Citation(s) in RCA: 140] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
PURPOSE Objectives of this study were to: 1) develop iLTSL, a low temperature sensitive liposome co-loaded with an MRI contrast agent (ProHance® Gd-HP-DO3A) and doxorubicin, 2) characterise doxorubicin and Gd-HP-DO3A release from iLTSL and 3) investigate the ability of magnetic resonance-guided high intensity focused ultrasound (MR-HIFU) to induce and monitor iLTSL content release in phantoms and in vivo. METHODS iLTSL was passively loaded with Gd-HP-DO3A and actively loaded with doxorubicin. Doxorubicin and Gd-HP-DO3A release was quantified by fluorescence and spectroscopic techniques, respectively. Release with MR-HIFU was examined in tissue-mimicking phantoms containing iLTSL and in a VX2 rabbit tumour model. RESULTS iLTSL demonstrated consistent size and doxorubicin release kinetics after storage at 4°C for 7 days. Release of doxorubicin and Gd-HP-DO3A from iLTSL was minimal at 37°C but fast when heated to 41.3°C. The magnitude of release was not significantly different between doxorubicin and Gd-HP-DO3A over 10 min in HEPES buffer and plasma at 37°, 40° and 41.3°C (p > 0.05). Relaxivity of iLTSL increased significantly (p < 0.0001) from 1.95 ± 0.05 to 4.01 ± 0.1 mMs⁻¹ when heated above the transition temperature. Signal increase corresponded spatially and temporally to MR-HIFU-heated locations in phantoms. Signal increase was also observed in vivo after iLTSL injection and after each 10-min heating (41°C), with greatest increase in the heated tumour region. CONCLUSION An MR imageable liposome formulation co-loaded with doxorubicin and an MR contrast agent was developed. Stability, imageability, and MR-HIFU monitoring and control of content release suggest that MR-HIFU combined with iLTSL may enable real-time monitoring and spatial control of content release.
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Affiliation(s)
- Ayele H Negussie
- Center for Interventional Oncology, Radiology and Imaging Sciences, Clinical Center, National Institutes of Health, Bethesda, Maryland 20892, USA
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23
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Naposomes: a new class of peptide-derivatized, target-selective multimodal nanoparticles for imaging and therapeutic applications. Ther Deliv 2011; 2:235-57. [DOI: 10.4155/tde.10.86] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Modified supramolecular aggregates for selective delivery of contrast agents and/or drugs are examined with a focus on a new class of peptide-derivatized nanoparticles: naposomes. These nanoparticles are based on the co-aggregation of two different amphiphilic monomers that give aggregates of different shapes and sizes (micelles, vesicles and liposomes) with diameters ranging between 10 and 300 nm. Structural properties and in vitro and in vivo behaviors are discussed. For the high relaxitivity values (12–19 mM-1s-1) and to detect for the presence of a surface-exposed peptide, the new peptide-derived supramolecular aggregates are very promising candidates as target-selective MRI contrast agents. The efficiency of surface-exposed peptides in homing these nanovectors to a specific target introduces promising new opportunities for the development of diagnostic and therapeutic agents with high specificity toward the biological target and reduced toxic side effects on nontarget organs.
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24
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Size of thermosensitive liposomes influences content release. J Control Release 2010; 147:436-43. [DOI: 10.1016/j.jconrel.2010.08.013] [Citation(s) in RCA: 85] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2010] [Revised: 07/15/2010] [Accepted: 08/09/2010] [Indexed: 11/24/2022]
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25
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Plush SE, Woods M, Zhou YF, Kadali SB, Wong MS, Sherry AD. Nanoassembled capsules as delivery vehicles for large payloads of high relaxivity Gd3+ agents. J Am Chem Soc 2010; 131:15918-23. [PMID: 19810734 DOI: 10.1021/ja906981w] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Nanoassembled capsules (NACs) that incorporate a polymer aggregate inside a silica shell may be loaded with agents that are of particular interest for therapeutic or diagnostic applications. NACs formed using the MRI contrast agent GdDOTP(5-) in the internal polymer aggregate are reported herein, the smaller of which show promise as potential MRI contrast agents. Unlike many other nanoencapsulated systems, water access to the inner core of these NACs does not appear to be limited and consequently the water relaxivity per Gd(3+) agent can reach as high as 24 mM(-1) s(-1). Robust, spherical capsules were formed using polyallylamine or poly-L-lysine ranging from 0.2 to 5 microm in diameter. The greatest gains in relaxivity were observed for smaller NACs, for which water accessibility remained high but molecular rotation of the Gd(3+) chelate was effectively restricted. Larger NACs did not afford such large gains in relaxivity, the result of poorer water accessibility combined with less-effective rotational restriction.
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Affiliation(s)
- Sally E Plush
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, 5325 Harry Hines Boulevard, Dallas, Texas 75235, USA
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26
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Supramolecular aggregates containing lipophilic Gd(III) complexes as contrast agents in MRI. Coord Chem Rev 2009. [DOI: 10.1016/j.ccr.2009.01.015] [Citation(s) in RCA: 116] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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27
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Mody VV, Nounou MI, Bikram M. Novel nanomedicine-based MRI contrast agents for gynecological malignancies. Adv Drug Deliv Rev 2009; 61:795-807. [PMID: 19427886 DOI: 10.1016/j.addr.2009.04.020] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2008] [Accepted: 04/28/2009] [Indexed: 11/16/2022]
Abstract
Gynecological cancers result in significant morbidity and mortality in women despite advances in treatment and diagnosis. This is due to detection of the disease in the late stages following metastatic spread in which treatment options become limited and may not result in positive outcomes. In addition, traditional contrast agents are not very effective in detecting primary metastatic tumors and cells due to a lack of specificity and sensitivity of the diagnostic tools, which limits their effectiveness. Recently, the field of nanomedicine-based contrast agents offers a great opportunity to develop highly sophisticated devices that can overcome many traditional hurdles of contrast agents including solubility, cell-specific targeting, toxicities, and immunological responses. These nanomedicine-based contrast agents including liposomes, micelles, dendrimers, multifunctional magnetic polymeric nanohybrids, fullerenes, and nanotubes represent improvements over their traditional counterparts, which can significantly advance the field of molecular imaging.
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Affiliation(s)
- Vicky V Mody
- Department of Pharmacological and Pharmaceutical Sciences, University of Houston, Texas Medical Center Campus, 1441 Moursund Street, Houston, Texas 77030, USA
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28
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Pan D, Lanza GM, Wickline SA, Caruthers SD. Nanomedicine: perspective and promises with ligand-directed molecular imaging. Eur J Radiol 2009; 70:274-85. [PMID: 19268515 DOI: 10.1016/j.ejrad.2009.01.042] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2009] [Accepted: 01/14/2009] [Indexed: 01/01/2023]
Abstract
Molecular imaging and targeted drug delivery play an important role toward personalized medicine, which is the future of patient management. Of late, nanoparticle-based molecular imaging has emerged as an interdisciplinary area, which shows promises to understand the components, processes, dynamics and therapies of a disease at a molecular level. The unprecedented potential of nanoplatforms for early detection, diagnosis and personalized treatment of diseases, have found application in every biomedical imaging modality. Biological and biophysical barriers are overcome by the integration of targeting ligands, imaging agents and therapeutics into the nanoplatform which allow for theranostic applications. In this article, we have discussed the opportunities and potential of targeted molecular imaging with various modalities putting a particular emphasis on perfluorocarbon nanoemulsion-based platform technology.
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Affiliation(s)
- Dipanjan Pan
- Department of Medicine, Washington University Medical School, St Louis, MO, USA.
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Terreno E, Delli Castelli D, Violante E, Sanders HMHF, Sommerdijk NAJM, Aime S. Osmotically shrunken LIPOCEST agents: an innovative class of magnetic resonance imaging contrast media based on chemical exchange saturation transfer. Chemistry 2009; 15:1440-8. [PMID: 19115311 DOI: 10.1002/chem.200801766] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The peculiar properties of osmotically shrunken liposomes acting as magnetic resonance imaging-chemical exchange saturation transfer (MRI-CEST) contrast agents have been investigated. Attention has been primarily devoted to assessing the contribution arising from encapsulated and incorporated paramagnetic lanthanide(III)-based shift reagents in determining the chemical shift of the intraliposomal water protons, which is a relevant factor for generating the CEST contrast. It is demonstrated that a highly shifted resonance for the encapsulated water can be attained by increasing the percentage of the amphiphilic shift reagent incorporated in the liposome bilayer. It is also demonstrated that the shift contribution arising from the bulk magnetic susceptibility can be optimized through the modulation of the osmotic shrinkage. In terms of sensitivity, it is shown that the saturation transfer efficiency can be significantly improved by increasing the size of the vesicle, thus allowing a high number of exchangeable protons to be saturated. In addition, the role played by the intensity of the saturating radiofrequency field has also been highlighted.
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Affiliation(s)
- Enzo Terreno
- Department of Chemistry IFM and Molecular Imaging Center, University of Torino, Via P. Giuria 7, 10125 Torino, Italy
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Boutry S, Brunin S, Mahieu I, Laurent S, Vander Elst L, Muller RN. Magnetic labeling of non-phagocytic adherent cells with iron oxide nanoparticles: a comprehensive study. CONTRAST MEDIA & MOLECULAR IMAGING 2009; 3:223-32. [PMID: 19072771 DOI: 10.1002/cmmi.256] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Small particles of iron oxide (SPIO) and ultrasmall particles of iron oxide (USPIO), inducing a strong negative contrast on T(2) and T(2)*-weighted MR images, are the most commonly used systems for the magnetic labeling of cultured cells and their subsequent detection by magnetic resonance imaging (MRI). The purpose of this work is to study the influence of iron incubation concentration, nanoparticle size and nanoparticle coating on the magnetic labeling and the viability of non-phagocytic adherent cells in culture. The magnetic labeling of 3T6 fibroblasts was studied by T(2)-weighted MRI at 4.7 T and by dosing-or cytochemical revealing-of iron through methods based on Perl's Prussian blue staining. Cells were incubated for 48 h with increasing iron concentrations of SPIO (25-1000 microg Fe/ml Endorem. Sinerem, a USPIO (20-40 nm) coated with neutral dextran, and Resovist (65 nm), a SPIO bearing an anionic carboxydextran coating, were compared with Endorem (dextran-coated, 80-150 nm) as magnetic tags. The iron loading of marrow stromal cell primary cultures (MSCs) isolated from rat femurs was compared with that of 3T6 fibroblasts. The SPIO-labeling of cells with Endorem was found to be dependent on the iron incubation concentration. MSCs, more sparsely distributed in the culture, exhibited higher iron contents than more densely populated 3T6 fibroblast cultures. A larger iron loading was achieved with Resovist than with Endorem, which in turn was more efficient than Sinerem as a magnetic tag. The magnetic labeling of cultured non-phagocytic adherent cells with iron oxide nanoparticles was thus found to be dependent on the relative concentration of the magnetic tag and of the cells in culture, on the nanoparticle size, and on the coating type. The viability of cells, estimated by methods assessing cell membrane permeability, was not affected by magnetic labeling in the conditions used in this work.
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Affiliation(s)
- Sébastien Boutry
- Department of General, Organic and Biomedical Chemistry, NMR and Molecular Imaging Laboratory, University of Mons-Hainaut, Mons, Belgium
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Krause W, Klopp R, Leike J, Sachse A, Schuhmann-Giampieri G. Liposomes in Diagnostic Imaging – Comparison of Modalities – In-vivo Visualization of Liposomes -. J Liposome Res 2008. [DOI: 10.3109/08982109509039905] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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32
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Pütz B, Barsky D, Schulten K. Mechanisms of liposomal contrast agents in magnetic resonance imaging. J Liposome Res 2008. [DOI: 10.3109/08982109409018599] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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33
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Tilcock C. Liposomal blood pool agents for nuclear medicine and magnetic resonance imaging. J Liposome Res 2008. [DOI: 10.3109/08982109409018609] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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34
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Fritz T, Wu G, Shen D, Kulik B, New T, Crowell M, Wilke N, Unger E. Liposomal mr contrast agents. J Liposome Res 2008. [DOI: 10.3109/08982109409018601] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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35
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Determination of water permeability of paramagnetic liposomes of interest in MRI field. J Inorg Biochem 2008; 102:1112-9. [DOI: 10.1016/j.jinorgbio.2008.01.025] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2007] [Revised: 01/18/2008] [Accepted: 01/18/2008] [Indexed: 11/21/2022]
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36
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Zhao JM, Har-el YE, McMahon MT, Zhou J, Sherry AD, Sgouros G, Bulte JWM, van Zijl PCM. Size-induced enhancement of chemical exchange saturation transfer (CEST) contrast in liposomes. J Am Chem Soc 2008; 130:5178-84. [PMID: 18361490 PMCID: PMC2759111 DOI: 10.1021/ja710159q] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Liposome-based chemical exchange saturation transfer (lipoCEST) agents have shown great sensitivity and potential for molecular magnetic resonance imaging (MRI). Here we demonstrate that the size of liposomes can be exploited to enhance the lipoCEST contrast. A concise analytical model is developed to describe the contrast dependence on size for an ensemble of liposomes. The model attributes the increased lipoCEST contrast in smaller liposomes to their larger surface-to-volume ratio, causing an increased membrane water exchange rate. Experimentally measured rates correlate with size, in agreement with the model. The water permeability of liposomal membrane is found to be 1.11 +/- 0.14 microm/s for the specific lipid composition at 22 degrees C. Availability of the model allows rational design of the size of liposomes and quantification of their properties. These new theoretical and experimental tools are expected to benefit applications of liposomes to sensing the cellular environment, targeting and imaging biological processes, and optimizing drug delivery properties.
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37
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Laurent S, Elst LV, Thirifays C, Muller RN. Paramagnetic liposomes: inner versus outer membrane relaxivity of DPPC liposomes incorporating lipophilic gadolinium complexes. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2008; 24:4347-4351. [PMID: 18338913 DOI: 10.1021/la800148a] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Proton relaxometric properties of unilamellar DPPC liposomes embedding an amphiphilic paramagnetic chelate (Gd-DTPA-BC(14)A) in both layers of the phospholipid membrane or only in the external one are compared. The results show that the membrane's water permeability is able to quench the effect of the paramagnetic complexes located in the internal layer of DPPC liposomes, leading thus to an apparent lower global relaxivity.
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Affiliation(s)
- Sophie Laurent
- Department of General, Organic and Biomedical Chemistry, NMR and Molecular Imaging Laboratory, University of Mons-Hainaut, Mons, Belgium
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38
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Vaccaro M, Mangiapia G, Paduano L, Gianolio E, Accardo A, Tesauro D, Morelli G. Structural and relaxometric characterization of peptide aggregates containing gadolinium complexes as potential selective contrast agents in MRI. Chemphyschem 2008; 8:2526-38. [PMID: 17960748 DOI: 10.1002/cphc.200700505] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The structural and relaxometric characterization of a novel class of supramolecular aggregates, as potential tumor-specific contrast agents in magnetic resonance imaging (MRI), is reported. The aggregates are based on a new monomer with an upsilon shape (MonY) that contains, in the same molecule, all three fundamental tasks that are required: 1) a hydrophobic moiety that allows the formation of supramolecular aggregates; 2) the bioactive CCK8 peptide for target recognition; and 3) a chelating agent able to give stable gadolinium complexes. As indicated by dynamic light scattering and small-angle neutron scattering (SANS) measurements, MonY and its gadolinium complex MonY(Gd) aggregate in aqueous solution to give ellipsoidal micelles with a ratio between the micellar axes of approximately 1.7 and an aggregation number N(agg) of approximately 30. There are no differences in the aggregation behavior of MonY and MonY(Gd), which indicates that the presence of metal ions, and therefore the reduction of the net charge, does not influence the aggregation behavior. When MonY or MonY(Gd) are blended with dioleoyl phosphatidylcholine (DOPC), the aggregation behavior is dictated by the tendency of DOPC to give liposomes. Only when the amount of MonY or MonY(Gd) is higher than 20 % is the coexistence of liposomes and micelles observed. The thickness d of the bilayer is estimated by SANS to be approximately 35-40 A, whereas cryogenic transmission electron microscopy images show that the diameter of the liposomes ranges from approximately 50 to 150 nm. Self-assembling micelles of MonY(Gd) present high relaxivity values (r(1p)=15.03 mM(-1) s(-1)) for each gadolinium complex in the aggregate. Liposomes containing MonY(Gd) inserted in the DOPC bilayer at a molar ratio of 20:80 present slightly lower relaxivity values (r(1p)=12.7 mM(-1) s(-1)), independently of their internal or external position in the liposome.
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Affiliation(s)
- Mauro Vaccaro
- Department of Chemistry, University of Naples "Federico II", Via Cynthia, 80126 Naples, Italy
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Voisin P, Ribot EJ, Miraux S, Bouzier-Sore AK, Lahitte JF, Bouchaud V, Mornet S, Thiaudière E, Franconi JM, Raison L, Labrugère C, Delville MH. Use of Lanthanide-Grafted Inorganic Nanoparticles as Effective Contrast Agents for Cellular Uptake Imaging. Bioconjug Chem 2007; 18:1053-63. [PMID: 17511491 DOI: 10.1021/bc060269t] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The improvement of commonly used Gd3+ -based MRI agents requires the design of new systems with optimized in vivo efficacy, pharmacokinetic properties, and specificity. To design these contrast agents, two parameters are usually considered: increasing the number of coordinated water molecules or increasing the rotational correlation time by increasing molecular weight and size. This has been achieved by noncovalent or covalent binding of low-molecular weight Gd3+ chelates to macromolecules or polymers. The grafting of these high-spin paramagnetic gadolinium chelates on metal oxide nanoparticles (SiO2, Al2O3) is proposed. This new synthetic strategy presents at least two main advantages: (1) a high T1-relaxivity for MRI with a 275% increase of the MRI signal and (2) the ability of nanoparticles to be internalized in cells. Results indicate that these new contrast agents lead to a huge reconcentration of Gd3+ paramagnetic species inside microglial cells. This reconcentration phenomenon gives rise to high signal-to-noise ratios on MR images of cells after particle internalization, from 1.4 to 3.75, using Al2O3 or SiO2 particles, respectively. The properties of these new particles will be further used to get new insight into gene therapy against glioma, using microglial cells as vehicles to simultaneously transport a suicide gene and contrast agents. Since microglia are chemoattracted to brain tumors, the presence of these new contrast agents inside the cells will lead to a better MRI determination of the in vivo location, shape, and borders of the tumors. These Gd3+-loaded microglia can therefore provide effective localization of tumors by MRI before applying any therapeutic treatment. The rate of carcinoma remission following a suicide gene strategy is also possible.
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Affiliation(s)
- Pierre Voisin
- Résonance Magnétique des Systèmes Biologiques, UMR CNRS 5536, 146 rue Léo Saignat, F-33076 Bordeaux cedex France
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Sharma P, Brown SC, Walter G, Santra S, Scott E, Ichikawa H, Fukumori Y, Moudgil BM. Gd nanoparticulates: from magnetic resonance imaging to neutron capture therapy. ADV POWDER TECHNOL 2007. [DOI: 10.1163/156855207782515030] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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Accardo A, Tesauro D, Morelli G, Gianolio E, Aime S, Vaccaro M, Mangiapia G, Paduano L, Schillén K. High-relaxivity supramolecular aggregates containing peptides and Gd complexes as contrast agents in MRI. J Biol Inorg Chem 2006; 12:267-76. [PMID: 17143622 DOI: 10.1007/s00775-006-0186-6] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2006] [Accepted: 10/07/2006] [Indexed: 11/25/2022]
Abstract
Mixed supramolecular aggregates, obtained by assembling together two amphiphilic monomers (C(18)H(37))(2)NCO(CH(2))(2)CO(AdOO)(5)-G-CCK8 (AdOO is 8-amino-3,6-dioxaoctanoic acid, CCK8 is C-terminal octapeptide of cholecystokinin) and (C(18)H(37))(2)NCO(CH(2))(2)COLys(DTPAGlu)CONH(2) (DTPAGlu is N,N-bis[2-[bis(carboxyethyl)amino]ethyl]-L-glutamic acid), are characterized for their structural parameters by dynamic light scattering and for their relaxometric properties, in the absence and in the presence of 0.9 wt% NaCl. Two different aggregates (micelles and bilayer structures) are present in the absence of NaCl, while only bilayer structures are observed at physiological ionic strength. The presence of NaCl increases the ionic strength, promoting a decrease in the repulsions between the polar heads and among the aggregates in solution, thus supporting the formation of large-curvature aggregates such as bilayer structures like vesicles. In these conditions the closed, vesicular shape and the large size (hydrodynamic radius of about 300 A) of the aggregates allow a high number of paramagnetic gadolinium complexes and bioactive peptides to be accommodated on the inner and external surfaces . The presence of the salt causes a variation in the structural arrangement of the molecules and a partial rigidification of the assembled Gd(III) complexes on the surface vesicles, reducing their internal motions and giving an approximately 15% higher relaxivity value (r (1p) = 21.0 and 18.6 Mm(-1) s(-1) in the presence and in the absence of NaCl, respectively). The vesicles obtained, for the high relaxivity of each gadolidium complex and for the presence of a surface-exposed bioactive peptide, are very promising candidates as target-selective MRI contrast agents.
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Affiliation(s)
- Antonella Accardo
- Centro Interuniversitario per la Ricerca sui Peptidi Bioattivi, Department of Biological Science, University of Naples Federico II & IBB-CNR, Naples, 80134, Italy
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42
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Aime S, Delli Castelli D, Terreno E. Highly sensitive MRI chemical exchange saturation transfer agents using liposomes. Angew Chem Int Ed Engl 2006; 44:5513-5. [PMID: 16052647 DOI: 10.1002/anie.200501473] [Citation(s) in RCA: 170] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Silvio Aime
- Dipartimento di Chimica I.F.M. Via P. Giuria 7, 10125, Torino, Italy.
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Mulder WJM, Strijkers GJ, van Tilborg GAF, Griffioen AW, Nicolay K. Lipid-based nanoparticles for contrast-enhanced MRI and molecular imaging. NMR IN BIOMEDICINE 2006; 19:142-64. [PMID: 16450332 DOI: 10.1002/nbm.1011] [Citation(s) in RCA: 366] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
In the field of MR imaging and especially in the emerging field of cellular and molecular MR imaging, flexible strategies to synthesize contrast agents that can be manipulated in terms of size and composition and that can be easily conjugated with targeting ligands are required. Furthermore, the relaxivity of the contrast agents, especially for molecular imaging applications, should be very high to deal with the low sensitivity of MRI. Lipid-based nanoparticles, such as liposomes or micelles, have been used extensively in recent decades as drug carrier vehicles. A relatively new and promising application of lipidic nanoparticles is their use as multimodal MR contrast agents. Lipids are amphiphilic molecules with both a hydrophobic and a hydrophilic part, which spontaneously assemble into aggregates in an aqueous environment. In these aggregates, the amphiphiles are arranged such that the hydrophobic parts cluster together and the hydrophilic parts face the water. In the low concentration regime, a wide variety of structures can be formed, ranging from spherical micelles to disks or liposomes. Furthermore, a monolayer of lipids can serve as a shell to enclose a hydrophobic core. Hydrophobic iron oxide particles, quantum dots or perfluorocarbon emulsions can be solubilized using this approach. MR-detectable and fluorescent amphiphilic molecules can easily be incorporated in lipidic nanoparticles. Furthermore, targeting ligands can be conjugated to lipidic particles by incorporating lipids with a functional moiety to allow a specific interaction with molecular markers and to achieve accumulation of the particles at disease sites. In this review, an overview of different lipidic nanoparticles for use in MRI is given, with the main emphasis on Gd-based contrast agents. The mechanisms of particle formation, conjugation strategies and applications in the field of contrast-enhanced, cellular and molecular MRI are discussed.
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Affiliation(s)
- Willem J M Mulder
- Biomedical NMR, Department of Biomedical Engineering, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands.
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Aime S, Delli Castelli D, Terreno E. Highly Sensitive MRI Chemical Exchange Saturation Transfer Agents Using Liposomes. Angew Chem Int Ed Engl 2005. [DOI: 10.1002/ange.200501473] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Lanza GM, Winter PM, Caruthers SD, Morawski AM, Schmieder AH, Crowder KC, Wickline SA. Magnetic resonance molecular imaging with nanoparticles. J Nucl Cardiol 2004; 11:733-43. [PMID: 15592197 DOI: 10.1016/j.nuclcard.2004.09.002] [Citation(s) in RCA: 90] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Molecular imaging agents are extending the potential of noninvasive medical diagnosis from basic gross anatomic descriptions to complicated phenotypic characterizations based on the recognition of unique cell surface biochemical signatures. Although originally the purview of nuclear medicine, molecular imaging is now a prominent feature of most clinically relevant imaging modalities, in particular magnetic resonance (MR) imaging. MR nanoparticulate agents afford the opportunity not only for targeted diagnostic studies but also for image-monitored site-specific therapeutic delivery, much like the "magic bullet" envisioned by Paul Erhlich 100 years ago. Combining high-resolution MR molecular imaging with drug delivery will facilitate verification and quantification of treatment (ie, rational targeted therapy) and will offer new clinical approaches to many diseases.
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Affiliation(s)
- Gregory M Lanza
- Division of Cardiology, Washington University Medical School, 660 S. Euclid Avenue, St. Louis, MO 63110, USA
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Alhaique F, Bertini I, Fragai M, Carafa M, Luchinat C, Parigi G. Solvent 1H NMRD study of biotinylated paramagnetic liposomes containing Gd-bis-SDA-DTPA or Gd-DMPE-DTPA. Inorganica Chim Acta 2002. [DOI: 10.1016/s0020-1693(01)00779-4] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Abstract
Pharmaceutical agents labeled with both boron and gadolinium have potential applications in both boron neutron capture therapy (NCT) and magnetic resonance imaging. Pre- and post-injection T1 maps provide a method for the indirect measurement of the gadolinium and boron concentrations that can then be used in NCT treatment planning. This requires an understanding of the relaxation properties of the agent. In this paper we present an analysis of the relaxation properties of a dual boron and gadolinium agent, Gd (III)-diethylenetriaminepentaacetate-carborane [Gd (III)-DTPA-carborane], in vitro in the presence and absence of serum albumin. The nuclear magnetic relaxation dispersion profile of solutions containing albumin obtained with a field cycling relaxometer exhibit a peak in the frequency range from 8 to 50 MHz. This indicates a long rotational correlation time relative to the solution without serum albumin. Results from other experiments indicate that this peak results from the binding of Gd (III)-DTPA-carborane derivative to serum albumin. Temperature studies indicate that the water proton relaxation efficiency of bound agent is limited by the water residence time as the relaxivity increases from 19 +/- 1 to 32.6 +/-; 0.8 (sec.mM)-1 when the temperature is increased from 5 to 35 degrees C.
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Affiliation(s)
- A T Tatham
- Nuclear Engineering Department, University of Illinois at Urbana Champaign 61801, USA
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Males RG, Herring FG. A 1H-NMR study of the permeation of glycolic acid through phospholipid membranes. BIOCHIMICA ET BIOPHYSICA ACTA 1999; 1416:333-8. [PMID: 9889392 DOI: 10.1016/s0005-2736(98)00236-3] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
The transmembrane permeability coefficient of the alpha-hydroxyacid, glycolic acid, has been measured for egg phosphatidylcholine large unilamellar vesicles. The determination of the vesicle concentration independent first-order rate constant for membrane transport and the permeability coefficient were made using an NMR technique employing shift agents. Both the temperature dependence and the dependence on cholesterol content were investigated. The activation energy and the Arrhenius pre-exponential factor were found to be dependent on the cholesterol content. A marked increase in both parameters was observed up to 20 mol% cholesterol, with a further, small increase up to 50%. The pH dependence of permeability was also investigated. An increase in permeability is observed with a decrease in pH, providing a possible explanation for the effectiveness of glycolic acid in skin treatment.
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Affiliation(s)
- R G Males
- Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, BC V6T 1Z1, Canada
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Fossheim SL, Fahlvik AK, Klaveness J, Muller RN. Paramagnetic liposomes as MRI contrast agents: influence of liposomal physicochemical properties on the in vitro relaxivity. Magn Reson Imaging 1999; 17:83-9. [PMID: 9888401 DOI: 10.1016/s0730-725x(98)00141-6] [Citation(s) in RCA: 127] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
The in vitro contrast efficacy of liposome encapsulated gadolinium-[10-(2-hydroxypropyl)-1,4,7,10-tetraazacyclododecane-1, 4,7-triacetic acid] (GdHPDO3A) has been assessed by relaxometry. The internal concentrations were 150 and 250 mM Gd. Two types of liposome compositions were investigated: a phospholipid blend consisting of both hydrogenated phosphatidylcholine (HPC) and phosphatidylserine (HPS) with a gel-to-liquid crystalline phase transition temperature (Tm) of 50 degrees C, and a mixture of dipalmitoylphosphatidylcholine (DPPC) and dipalmitoylphosphatidylglycerol (DPPG) with a Tm of 41 degrees C. The investigated liposome size range was 70-400 nm. The T1 and T2 relaxivities (r1 and r2) of liposome encapsulated GdHPDO3A were significantly reduced at 37 degrees C and 0.47 T, compared to those of non-liposomal metal chelate, due to an exchange limitation of the dipolar relaxation process. The highest relaxivity values were obtained for the DPPC/DPPG liposomes, and were attributed to a higher liposome water permeability and to a more efficient water exchange across the membrane. A reduction in liposome size increased the r1, confirming the exchange limited dipolar relaxation. The increased r1 with increasing temperature demonstrated the prerequisite of rapid water exchange between the interior and exterior of the liposome for efficient dipolar relaxation enhancement. Susceptibility effects were present in the liposome systems as the r2/r1 ratio increased with increasing liposome size and internal Gd concentration. In summary, the current work has shown the influence of key physicochemical properties, such as liposome size, membrane composition and permeability, on the in vitro relaxivity of liposome encapsulated GdHPDO3A.
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Affiliation(s)
- S L Fossheim
- Dept. of Medicinal Chemistry, School of Pharmacy, University of Oslo, Norway
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