Monomer-collagen interactions studied by saturation transfer difference NMR.

Functional monomers in dentin adhesives are involved in wetting dental substrates, demineralization, and the formation of calcium salts. However, the interaction of these monomers with collagen is not understood at a molecular/atomic level. We performed saturation transfer difference (STD) NMR spectroscopy to investigate the binding interaction of 2 functional monomers, 4-methacryloyloxyethyl trimellitate anhydride (4-META) and 10-methacryloyloxydecyl dihydrogenphosphate (MDP), with atelocollagen as a triple-helical peptide model. High STD intensities were detected on the protons in the aliphatic region in MDP, whereas they were not detected for 4-META. The STD results imply that MDP has a relatively stable interaction with the collagen, because of the hydrophobic interactions between the hydrophobic MDP moieties and the hydrophobic collagen surface. This finding indicates that MDP-collagen complexation accounts for stable dentin bonding.