Adhesion of N-methacryloyl-ω-amino acid primers to collagen analyzed by 13C NMR

Previously, we reported that the strength of the interaction between N-methacryloyl-omega -amino acid (NM omegaA) primers and dentinal collagen exhibited a strong correlation with the bond strength of the resin to etched dentin. To determine the pertinent functional groups of the amino acid residues in the dentinal collagen, to which the amide and/or the carboxylic acid groups of the NM omega As are adsorbed, we used C-13 NMR techniques-primarily through the observation of spin-lattice relaxation times, T-i-to investigate the adsorption characteristics resulting from the interaction of NM omega As with a model oligopeptide for collagen, (PPG)(5). The addition of NM omega As to a collagenous solution resulted in a decrease in the T-1 values of the carbonyl carbons attributed to the carboxylic acid of the C-terminal Gly and to the third amide of the N-terminal Pro residues in the (PPG)(5) molecule, thus reflecting the formation of hydrogen-bonded interactions.