Lothar Helm

Office: PH A2 354
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Office: PH A2 354
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Biographie Publications Enseignement et PhD

Lothar Helm was born in Gernsbach (Germany) in 1952. He studied physics at the University of Karlsruhe (Germany) and obtained his diploma degree in 1977. He remained in Karlsruhe for his Ph.D. research with Prof. H. G. Hertz and received his degree in physical chemistry in 1980. In 1980 he joined the laboratories of Prof. André Merbach at the University of Lausanne, Switzerland. From 1983 to 2001 he was maître d’enseignement et de recherche at the Faculty of Science of the University of Lausanne. In 2001 he moved, together with the whole chemistry department, from the University of Lausanne to the Ecole Polytechnique Fédérale de Lausanne (EPFL). Since 2006 he is adjunct professor at the Institute of Chemical Sciences and Engineering at EPFL and director of the NMR services of the institute. From 2007 to 2011 he was director of the "Conférence du corps Enseignant" at EPFL. Since 2011 he is member of the School Assembly of EPFL (AE). MAIN RESEARCH INTERESTS: • Physico-chemical studies of contrast agents for medical magnetic resonance imaging (MRI) • Study of reactivity and reaction mechanisms in coordination chemistry by variable temperature and pressure nuclear magnetic resonance • Computer simulation of solvent dynamics on cations and metal complexes in solution Professional course

Publications représentatives

Gold Nanoparticles Functionalized with Gadolinium Chelates as High-Relaxivity MRI Contrast Agents.

Loïck Moriggi, Caroline Cannizzo, Eddy Dumas, Cédric R. Mayer, Alexey Ulianov, and Lothar Helm
Published in J. Am. Chem. Soc., 2009, 131, 10828-10829. in

Nuclear Spin Relaxation Parameters of MRI Contrast Agents – Insight from Quantum Mechanical Calculations.

Oleg V. Yazyev and Lothar Helm
Published in Eur. J. Inorg. Chem., 2008, 201-211, in

Destroying Gadofullerene Aggregates by Salt Addition in Aqueous Solution of Gd@C60(OH)x and Gd@C60[C(COOH2)]10

Sabrina Laus, Balaji Sitharaman, Éva Tóth, Robert D. Bolskar, Lothar Helm, Subashini Asokan, Michael S. Wong, Lon J. Wilson and André E. Merbach
Published in J. Am. Chem. Soc., 2005, 127, 9368-9369 in

Water-soluble Gadofullerenes: Toward High-Relaxivity, pH-responsive MRI Contrast Agents.

Éva Tóth, Robert D. Bolskar, Alain Borel, Gabriel González, Lothar Helm, André E. Merbach, Balaji Sitharaman and Lon J. Wilson
Published in J. Am. Chem. Soc., 2005, 127, 799-805. in

Inorganic and Bioinorganic Solvent Exchange Mechanisms.

Lothar Helm and André E. Merbach.
Published in Chem, Rev., 2005, 105, 1923-1959 in

Water and Proton Exchange Processes on Metal Ions.

Lothar Helm, Gaëlle Nicolle, André E. Merbach
Published in Adv. Inorg. Chem., 2005, 57, 327-379. in

Lanthanide Ions as Magnetic Resonance Imaging Agents. Nuclear and Electronic Relaxation Properties. Applications.

Lothar Helm, Éva Tóth and André E. Merbach.
Published in In Metal Ions in Biological Systems – Vol. 40., Ed. by A. and H. Sigel, eds, M. Dekker, New York, 2003, 589-641. in

Pharmacokinetics and biodistribution study of self-assembled Gd-micelles demonstrating blood-pool contrast enhancement for MRI

V. Vorobiev; A. Babic; L. A. Crowe; Y. Van de Looij; S. Lenglet et al.

International Journal of Pharmaceutics. 2019. DOI : 10.1016/j.ijpharm.2019.118496.

Lothar Helm

Publications représentatives

Gold Nanoparticles Functionalized with Gadolinium Chelates as High-Relaxivity MRI Contrast Agents.

Nuclear Spin Relaxation Parameters of MRI Contrast Agents – Insight from Quantum Mechanical Calculations.

Destroying Gadofullerene Aggregates by Salt Addition in Aqueous Solution of Gd@C60(OH)x and Gd@C60[C(COOH2)]10

Water-soluble Gadofullerenes: Toward High-Relaxivity, pH-responsive MRI Contrast Agents.

Inorganic and Bioinorganic Solvent Exchange Mechanisms.

Water and Proton Exchange Processes on Metal Ions.

Lanthanide Ions as Magnetic Resonance Imaging Agents. Nuclear and Electronic Relaxation Properties. Applications.

Pharmacokinetics and biodistribution study of self-assembled Gd-micelles demonstrating blood-pool contrast enhancement for MRI

The Periodic Table and Kinetics?

MRI micelles self-assembled from synthetic gadolinium-based nano building blocks

Carbazole as Linker for Dinuclear Gadolinium-Based MRI Contrast Agents

Self-Assembled Nanomicelles as MRI Blood-Pool Contrast Agent

Complexation of [Gd(DTTA–Me)(H2O)2]− by Fluoride and Its Consequences to Water Exchange

Water Exchange on [Ln(DO3A)(H2O)2] and [Ln(DTTA–Me)(H2O)2]− Studied by Variable Temperature, Pressure, and Magnetic Field NMR

Evaluation of Water Exchange Kinetics on [Ln(AAZTAPh–NO2)(H2O)q]x Complexes Using Proton Nuclear Magnetic Resonance

In-Vivo Detection and Tracking of T Cells in Various Organs in a Melanoma Tumor Model by F-19-Fluorine MRS/MRI

Transient versus Static Electron Spin Relaxation in Mn2+ Complexes Relevant as MRI Contrast Agents

Collisional cross-section of water molecules in vapour studied by means of H-1 relaxation in NMR

Dinuclear DOTA-Based Gd-III Chelates - Revisiting a Straightforward Strategy for Relaxivity Improvement

PEGylated DOTA-AHA-Based Gd-III Chelates: A Relaxometric Study

Prototropic Exchange Governs T-1 and T-2 Relaxivities of a Potential MRI Contrast Agent Nanozeolite Gd-LTL with a High pH Responsiveness

A Pyridine-Based Ligand with Two Hydrazine Functions for Lanthanide Chelation: Remarkable Kinetic Inertness for a Linear, Bishydrated Complex

Solvent Exchange and Electron-Spin Relaxation on Homoleptic Acetonitrile Complexes of Trivalent Lanthanides

Metal Complexes as MRI Contrast Enhancement Agents

Gold nanoparticles functionalised with fast water exchanging Gd3+ chelates: linker effects on the relaxivity

Dynamic aggregation of the mid-sized gadolinium complex {Ph-4[Gd(DTTA)(H2O)(2)](-)(3)}

Gd(DOTAlaP): Exploring the Boundaries of Fast Water Exchange in Gadolinium-Based Magnetic Resonance Imaging Contrast Agents

The Chemistry of Contrast Agents in Medical Magnetic Resonance Imaging

Speciation of aqueous tellurium(IV) in hydrothermal solutions and vapors, and the role of oxidized tellurium species in Te transport and gold deposition

Relaxivity of gadolinium(III) complexes: theory and mechanism

H-1 and O-17 NMR Relaxometric and Computational Study on Macrocyclic Mn(II) Complexes

NMR and Electron Paramagnetic Resonance Studies of [Gd(CH3CN)(9)](3+) and [Eu(CH3CN)(9)](2+): Solvation and Solvent Exchange Dynamics in Anhydrous Acetonitrile

Electronic fine structure calculation of [Gd(DOTA)(H2O)]- using LF-DFT: The zero field splitting

Hyperfine Coupling Constants on Inner-Sphere Water Molecules of Gd-III-Based MRI Contrast Agents

New Bisaqua Picolinate-Based Gadolinium Complexes as MRI Contrast Agents with Substantial High-Field Relaxivities

Serum Albumin Targeted, pH-Dependent Magnetic Resonance Relaxation Agents

O-17 NMR and Density Functional Theory Study of the Dynamics of the Carboxylate Groups in DOTA Complexes of Lanthanides in Aqueous Solution

Pyridine-Based Lanthanide Complexes Combining MRI and NIR Luminescence Activities

Isoquinoline-Based Lanthanide Complexes: Bright NIR Optical Probes and Efficient MRI Agents

Gadolinium complexes of monophosphinic acid DOTA derivatives conjugated to cyclodextrin scaffolds: efficient MRI contrast agents for higher magnetic fields

Gold nanoparticles functionalised with stable, fast water exchanging Gd3+ chelates as high relaxivity contrast agents for MRI

Gadolinium-Based Bionanomaterials for Magnetic Resonance Imaging

The challenge of T1 contrast agents for high-magnetic field MRI

NMR of Insensitive Nuclei Enhanced by Dynamic Nuclear Polarization

NMR Study of Ligand Exchange and Electron Self-Exchange between Oxo-Centered Trinuclear Clusters [Fe3(μ3-O)(μ-O2CR)6(4-R´py)3]+/0

Synthesis, complexation and NMR relaxation properties of Gd3+ complexes of Mes(DO3A)3

Mn2+ Complexes with 12-Membered Pyridine Based Macrocycles Bearing Carboxylate or Phosphonate Pendant Arm: Crystallographic, Thermodynamic, Kinetic, Redox, and 1H/17O Relaxation Studies

Kinetics of Yttrium-Ligand Complexation Monitored Using Hyperpolarized 89Y as a Model for Gadolinium in Contrast Agents

Geometrical confinement of gadolinium-based contrast agents in nanoporous particles enhances T1 contrast

Isomerization Mechanisms of Stereolabile tris- and bis-Bidentate Octahedral Cobalt(II) Complexes: X-ray Structure and Variable Temperature and Pressure NMR Kinetic Investigation

Optimization of gadolinium-based MRI contrast agents for high magnetic‑field applications

Synthesis, structures and characterisations of truly homoleptic acetonitrile Ln3+ complexes in solid state and in solution

Multiple Frequency and Variable Temperature EPR study of Gd(III) polyaminocarboxylates: analysis and comparison of the magnetically dilute powder and the frozen solution spectra

Lanthanide chelates of (bis)-hydroxymethyl-substituted DTTA with potential application as contrast agents in magnetic resonance imaging

Gold Nanoparticles Functionalized with Gadolinium Chelates as High-Relaxivity MRI Contrast Agents

Gadolinium(III) complexes of 1,4,7-triazacyclononane based picolinate ligands: simultaneous optimization of water exchange kinetics and electronic relaxation

A ruthenium-based metallostar: synthesis, sensitized luminescence and 1H relaxivity

Physicochemical Properties of the High-Field MRI-Relevant [Gd(DTTA-Me)(H2O)2]− Complex

In vivo MRI assessment of a novel GdIII-based contrast agent designed for high magnetic field applications

Gd(III)-EPTPAC16, a new self-assembling potential liver MRI contrast agent: in vitro characterization and in vivo animal imaging studies

Comparison of different methods for calculating the paramagnetic relaxation enhancement of nuclear spins as a function of the magnetic field

Novel DOTA-based prochelator for divalent peptide vectorization: synthesis of dimeric bombesin analogues for multimodality tumor imaging and therapy

Gadonanotubes as Ultrasensitive pH-Smart Probes for Magnetic Resonance Imaging

Nuclear Spin Relaxation Parameters of MRI Contrast Agents – Insight from Quantum Mechanical Calculations

Ligand exchange and complex formation kinetics studied by NMR exemplified on fac-[(CO)3M(H2O)]+ (M = Mn, Tc, Re)

Towards the Rational Design of MRI Contrast Agents: Electron Spin Relaxation Is Largely Unaffected by the Coordination Geometry of Gadolinium(III)-DOTA-Type Complexes

A benzene-core trinuclear GdIII complex: towards the optimization of relaxivity for MRI contrast agent applications at high magnetic field

Mechanism of Pyridine-Ligand Exchanges at the Different Labile Sites of 3d Heterometallic and Mixed Valence μ3-oxo Trinuclear Clusters

Multiple-frequency EPR spectra of two aqueous Gd3+ polyaminopolypyridinecarboxylate complexes: a study of high field effects

Gadolinium(III) ion in liquid water: structure, dynamics and magnetic interactions from first principles

Understanding Paramagnetic Relaxation Phenomena for Water-Soluble Gadofullerenes

Magnetism induced by single-atom defects in nanographites

Gadolinium(III) complexes of mono-and diethyl esters of monophosphinic acid analogue of DOTA as potential MRI contrast agents: solution structures and relaxometric studies

Physicochemical and MRI characterization of Gd3+-loaded polyamidoamine and hyperbranched dendrimers

Design of Gd(III)-Based Magnetic Resonance Imaging Contrast Agents: Static and Transient Zero-Field Splitting Contributions to the Electronic Relaxation and Their Impact on Relaxivity

H5EPTPACH2OH: Synthesis, Relaxometric Characterization and 1H NMR Spectroscopic Studies on the Solution Dynamics of Its LnIII Complexes

Early stages of radiation damage in graphite and carbon nanostructures: A first-principles molecular dynamics study

Defect-induced magnetism in graphene