Dentin interaction with universal adhesive containing isopropanol solvent studied by solid-state NMR spectroscopy.

Objective: This study investigated the chemical and structural changes in the mineral phase and collagen of dentin during application of a mild universal adhesive. Particular attention was paid to the role of isopropanol and changes in water molecules.

Methods: In vitro application of the mild universal adhesive on dentin with two established etching modes (self-etch and etch-and-rinse) was studied using solid state nuclear magnetic resonance spectroscopy.

Characterization of hydrogenated dentin components by advanced H solid-state NMR experiments.

Collecting information about molecular organisation on biological materials such as bone and dentin represents a major challenge in attaining a better understanding of their mechanical properties. To that end, solid state Nuclear Magnetic Resonance (ssNMR) spectroscopic study is an appropriate strategy to provide atomic structural details on these amorphous composite materials. However, species like water molecules and hydroxyl groups are usually observed through H magic angle spinning (MAS) ssNMR that suffers from poor resolution due to strong signal overlapping, making their identification difficult.

Molecular weights of cyclic and hollow clusters measured by DOSY NMR spectroscopy.

The Stokes-Einstein expression of the diffusion coefficient as a function of the hydrodynamic radius of the diffusing object does not explicitly carry the mass dependency of the object. It is possible to correlate the translational self-diffusion coefficients D with the molecular weight M for an ensemble of cyclic or hollow clusters ranging from about 200 to 30,000 g x mol(-1). From this correlation, the mass of a cluster can be deduced from its diffusion coefficient.

NMR measure of translational diffusion and fractal dimension. Application to molecular mass measurement.

Experimental NMR diffusion measure on polymers and on globular proteins are presented. These results, complemented with results found in the literature, enable a general description of effective fractal dimension for objects such as small organic molecules, sugars, polymers, DNA, and proteins. Results are compared to computational simulations as well as to theoretical values.

Two-dimensional DOSY experiment with Excitation Sculpting water suppression for the analysis of natural and biological media.

The Bipolar Pulse Pair Stimulated Echo NMR pulse sequence was modified to blend the original Excitation Sculpting water signal suppression. The sequence is a powerful tool to generate rapidly, with a good spectrum quality, bidimensional DOSY experiments without solvent signal, thus allowing the analysis of complex mixtures such as plant extracts or biofluids. The sequence has also been successfully implemented for a protein at very-low concentration in interaction with a small ligand, namely the salivary IB5 protein binding the polyphenol epigallocatechine gallate.