Exploration and exploitation of the uncommon pH profile of the dynamic covalent interactions between boronic acids and N-acetylneuraminic acids

In this review, the chemical mechanisms behind the interactions between boronic acids and N-acetylneuraminic acids, which have been widely utilized in biomedicine in recent decades, will be examined. It will also be highlighted that the affinity of boronic acids for N-acetylneuraminic acids is dependent on pH and is complementary to their...

MRI Contrast Agents in Glycobiology

Molecular recognition involving glycoprotein-mediated interactions is ubiquitous in both normal and pathological natural processes. Therefore, visualization of these interactions and the extent of expression of the sugars is a challenge in medical diagnosis, monitoring of therapy, and drug design. Here, we review the literature on the...

Response to Letter to the Editors: “Have we lost an essential link between coordination chemistry and medical applications?”

Lanthanopolyoxometalate-Silica Core/Shell Nanoparticles as Potential MRI Contrast Agents

The NMR relaxivities of the decatungstolanthanoate core-shell nanoparticles, prepared by encapsulating [Ln(W₅O₁₈)₂]⁹⁻ polyoxometalates (LnPOM) within amorphous silica shells (K₉[Ln(W₅O₁₈)₂]@SiO₂), were studied along the Ln series. The relaxivity...

Mn(III) porphyrins as potential MRI contrast agents for diagnosis and MRI-guided therapy

Mn(III) porphyrins have great potential as Gd-free MRI contrast agents because both the cation and the ligand have interesting properties. The redox properties of the Mn(III)-ion can be exploited for the preparation of reactive oxygen species for therapy. Moreover, the porphyrin ligand allows these complexes to have a high affinity for tumor...

Relaxivity of manganese ferrite nanoparticles

Manganese ferrite nanoparticles are superparamagnetic and have very high saturation magnetization, which makes them candidates for application as MRI contrast agents. Because these nanoparticles are very effective enhancers of transverse relaxation, they are particularly suitable as negative (T₂-weighted) contrast agents. The...

The chemical consequences of the gradual decrease of the ionic radius along the Ln-series

In the periodical system, the lanthanides (the 15 elements in the periodic table between barium and hafnium) are unique in the sense that their trivalent cations have their valence electrons hidden behind the 5s and 5p electrons. They show a gradual decrease in ionic radius with increasing atomic number (also known as the lanthanide...

A semi-empirical method for the estimation of the hydration number of Mn(II)-complexes

A semi-empirical equation to estimate the hydration number of Mn(II) complexes was derived from a database of 49 previously published ¹H longitudinal Nuclear Magnetic Relaxation Dispersion profiles. This equation has the longitudinal ¹H relaxivity and the molecular weight of the Mn(II) complex under consideration as...

Het cyclohexaanmodel van Böeseken

Surface PEG Grafting Density Determines Magnetic Relaxation Properties of Gd-Loaded Porous Nanoparticles for MR Imaging Applications

Surface PEGylation of nanoparticles designed for biomedical applications is a common and straightforward way to stabilize the materials for in vivo administration and to increase their circulation time. This strategy becomes less trivial when MRI active porous nanomaterials are concerned as their function relies on water/proton-exchange between...

The reliability of parameters obtained by fitting of ¹H NMRD profiles and ¹⁷O NMR data of potential Gd³⁺-based MRI contrast agents

Synthetic variable temperature ¹H NMRD profiles and ¹⁷O NMR relaxation and shift data were generated with a model based on the Solomon-Bloembergen-Morgan and Freed theories and then fitted simultaneously or individually. The effects of the fitting procedure and of experimental uncertainties on the resulting best-fit...

Glycoconjugate probes and targets for molecular imaging using magnetic resonance

Recently, many research activities in medical diagnosis have been devoted to molecular imaging with MRI. A key issue is the evaluation of molecular targets that allow the early detection and characterization of diseases and the assessment of the effects of therapy. The majority of the current targeting vectors are peptides and proteins; reports...

Liposomes with conjugates of a calix[4]arene and a Gd-DOTA derivative on the outside surface: An efficient potential contrast agent for MRI

Paramagnetic liposomes used as contrast agents in magnetic resonance imaging (MRI) often suffer from low efficacies because of slow water diffusion through the membrane. We present an approach to overcome this limitation by incorporation of a calix[4]arene based agent that expresses the chelates towards the bulk water.

Densely packed Gd(III)-chelates with fast water exchange on a calix[4]arene scaffold: A potential MRI contrast agent

A pyridine-N-oxide functionalized DOTA analogue has been conjugated to a calix[4]arene and the corresponding Gd-complex was characterized with respect to its suitability as MRI contrast agent. The compound forms spherical micelles in water with a cmc of 35 mMand a radius of 8.2 nm. The relaxivity of these aggregates is 31.2 s-1 mM-1 at 25ºC and...

In Vitro and In Vivo Behaviour of I111n Complexes of TTHA, TTHA-Bis(Butylamide) and TTHA-Bis(Glucamide): Stability, Biodistribution and Excretion Studied by Gamma Imaging

Aiming at radiopharmaceutical application, I111n3+ complexes of the polyaminocarboxylates TTHA, TTHA-bis(butylamide) and TTHA-bis(glucamide) were investigated. The in vitro stability of I111n(TTHA)3- and I111n(TTHA-bis(butylamide)- was evaluated by measuring the exchange of I111n3+ from the complexes to transferrin and the results were compared...

Selectieve oxydatieve oxidatie van sacchariden

Abstract of NL 9301614 (A) The invention relates to a method for the selective oxidative degradation of saccharides, wherein the oxidation is carried out with a peroxide, preferably hydrogen peroxide, in a basic medium in the presence of boric acid or a borate. The starting compound is preferably a saccharide which forms less stable borate...

Synthesis, configurational and conformational analysis of some types of cyclohexane and bicyclo[3.3.1]nonane derivates