Responsive Probes

Bonnet, Célia S.; Tei, Lorenzo; Botta, Maurizio; Tóth, Éva

doi:10.1002/9781118503652.ch8

Cited by 14 publications

(15 citation statements)

References 145 publications

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“…− . The relaxivity of GdL 3 is 6.7 mM −1 s −1 at 300 MHz and 37 °C, in comparison to 7.8 mM −1 s −1 at the same magnetic field and temperature for GdL 1 . Figure 4 depicts the relaxometric titration curves of GdL 3 with acetylcholine, γaminobutyric acid (GABA), aspartate, glutamate, glycine, and hydrogen carbonate.…”

Section: Inorganic Chemistrymentioning

confidence: 80%

“…Responsive magnetic resonance imaging (MRI) agents act as reporters of the biological environment where they are distributed by generating an MRI signal dependent on tissue parameters such as pH, concentration of endogeneous ions, enzymes, etc. 1 Combining MRI detection with complementary imaging techniques can provide additional, less ambiguous information. Multimodal approaches are becoming more common in both biomedical research and clinical imaging, and the development of responsive imaging agents with detection capabilities has recently triggered increasing interest.…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Toward MRI and Optical Detection of Zwitterionic Neurotransmitters: Near-Infrared Luminescent and Magnetic Properties of Macrocyclic Lanthanide(III) Complexes Appended with a Crown Ether and a Benzophenone Chromophore

et al. 2019

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Thanks to their versatile magnetic and luminescence features, lanthanide complexes have gained a central position in biomedical imaging as magnetic resonance imaging (MRI) contrast agents and optical imaging probes. In addition, appropriate chemical design allows modification of the magnetic relaxation properties of GdIII complexes and the optical properties of visible- or near-infrared (NIR)-emitting lanthanide chelates upon interaction with various biomarkers, which makes them ideal candidates for the creation of responsive agents. In this Forum Article, we demonstrate such design principles as well as the difficulties encountered in the context of neurotransmitter (NT) detection. Lanthanide(III) complexes of a macrocyclic ligand incorporating a benzophenone chromophore and a monoazacrown ether (LnL 3 ) have been synthesized as responsive probes to monitor amino acid NTs either in MRI (Ln = Gd) or in NIR optical detection (Ln = Nd or Yb). The parameters characterizing the water exchange and rotational dynamics of the gadolinium(III) complex were assessed by 17O NMR and 1H NMRD. In the presence of zwitterionic NTs, the inner-sphere water molecule is replaced by the carboxylate function of the NTs in the gadolinium(III) complex, leading to a decrease of the longitudinal relaxivity from 6.7 to 2–2.5 mM–1 s–1 (300 MHz and 37 °C). The apparent affinity constants range from K a = 35 for γ-aminobutyric acid (GABA) to 80 M–1 for glycine and glutamate, and there is no selectivity with respect to hydrogen carbonate (K a = 232; pH 7.4). The gadolinium(III) complex interacts with human serum albumin (HSA), resulting in a 60% increase in the relaxivity (20 MHz, 37 °C) in the absence of NTs. The HSA-bound complex, however, was revealed to be less responsive to NTs because of displacement of the GdIII-bound water by HSA, which was confirmed by the hydration number calculated from luminescence lifetimes of the HSA-bound europium(III) complex. The creation of an imaging agent suitable for NIR detection of NTs for an enhanced sensitivity in biological systems using the benzophenone (BP) moiety as the sensitizer of lanthanide luminescence was also attempted. Upon excitation at 300 nm of the BP chromophore in aqueous solutions of NdL 3 and YbL 3 , characteristic NIR emissions of NdIII and YbIII were observed because of 4F3/2 → 4I J (J = 9/2–13/2) and 2F5/2 → 2F7/2 transitions, respectively, indicating that this chromophore is a suitable antenna. Despite these promising results, luminescence titrations of NdIII and YbIII complexes with NTs were not conclusive because of chemical conversion of the ligand triggered by light, preventing quantitative analysis. The observed photochemical reaction of the ligand is strongly dependent on the nature of the lanthanide chelated; it is considerably slowed down in the presence of NdIII and EuIII.

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Section: Inorganic Chemistrymentioning

confidence: 80%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Toward MRI and Optical Detection of Zwitterionic Neurotransmitters: Near-Infrared Luminescent and Magnetic Properties of Macrocyclic Lanthanide(III) Complexes Appended with a Crown Ether and a Benzophenone Chromophore

et al. 2019

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“…These probes can change the MR signal upon alterations in the local environment, thus reporting the occurrence of a particular biological event. 1 Several classes of SCAs have been developed to date aiming to visualize and characterize various biological processes. 2,3 SCAs that respond to ions and molecules involved in neuronal signaling are of particular interest for neuroscience and could greatly help in understanding brain function.…”

Section: ■ Introductionmentioning

confidence: 99%

Innovative Design of Ca-Sensitive Paramagnetic Liposomes Results in an Unprecedented Increase in Longitudinal Relaxivity

et al. 2016

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Bioresponsive MRI contrast agents sensitive to Ca(II) fluctuations may play a critical role in the development of functional molecular imaging methods to study brain physiology or abnormalities in muscle contraction. A great challenge in their chemistry is the preparation of probes capable of inducing a strong signal variation that could be detected in a robust way. To this end, the incorporation of small molecular weight bioresponsive agents into nanocarriers can improve the overall properties in a few ways: (i) the agent can be delivered into the tissue of interest, increasing the local concentration; (ii) its biokinetic properties and retention time will improve; (iii) the high molecular weight and size of the nanocarrier may cause additional changes in the MRI signal and raise the chances for their detection in functional experiments. In this work, we report the preparation of the new class of liposome-based, Ca-sensitive MRI agents. We synthesized a novel amphiphilic ligand which was incorporated into the liposome bilayer. A remarkable increase of ∼420% in longitudinal relaxivity r 1 , from 7.3 mM −1 s −1 to 38.1 mM −1 s −1 at 25°C and 21.5 MHz in the absence and presence of Ca(II), respectively, was achieved by the most active liposomal formulation. To the best of our knowledge, this is the highest change in r 1 observed for Ca-sensitive agents at physiological pH and can be explained by simultaneous Ca-triggered increase in hydration and reduction of local motion of Gd(III) complex, which can be followed at low magnetic fields.

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“…22,23 Therefore it is important to develop metal chelates with both strong magnetic relaxivity to act as good contrast agents and good stability to ensure low toxicity. 24,25 Gd 3+ chelates have been the most frequently used contrast agents commercially because of their strong paramagnetic properties. Other more biocompatible paramagnetic metal chelates have also been investigated of viability as contrast agents.…”

mentioning

confidence: 99%

Paramagnetic relaxation based biosensor for selective dopamine detection

et al. 2015

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We report a new NMR relaxation time-based method for sensitive and selective dopamine detection using paramagnetic nanoparticles. The Fe(3+) species in the nanoparticles serves as both the contrast agent and the target recognition element. The results demonstrate that paramagnetic nanoparticles, similar to the more widely used superparamagnetic nanoparticles, can be integrated into relaxation based detection schemes while avoiding the aggregation problem commonly associated with superparamagnetic nanoparticles.

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Responsive Probes

Cited by 14 publications

References 145 publications

Toward MRI and Optical Detection of Zwitterionic Neurotransmitters: Near-Infrared Luminescent and Magnetic Properties of Macrocyclic Lanthanide(III) Complexes Appended with a Crown Ether and a Benzophenone Chromophore

Toward MRI and Optical Detection of Zwitterionic Neurotransmitters: Near-Infrared Luminescent and Magnetic Properties of Macrocyclic Lanthanide(III) Complexes Appended with a Crown Ether and a Benzophenone Chromophore

Innovative Design of Ca-Sensitive Paramagnetic Liposomes Results in an Unprecedented Increase in Longitudinal Relaxivity

Paramagnetic relaxation based biosensor for selective dopamine detection

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