Folic acid-nanodiamond complexes: interactions of nanodiamonds with folic acid

The article presents the results of a comparative analysis of the adsorption properties of detonation nanodiamonds (DNDs) with different surface functionalization (carboxyl and hydroxyl groups) with respect to folic acid (FA). A significant dependence of the adsorption activity of nanodiamonds on the type of functional surface groups was found. The amount of adsorbed FA on DNDs with hydroxyl groups is 3.5 times higher than the amount of FA adsorbed on DNDs with carboxyl groups, however, the bond strength of the hydroxyl groups of DND with FA is almost 300 times weaker than the bond strength in the DND-COOH+FA complex. Based on the experimental results and calculations of the charge distribution of the deprotonated FA molecule, a model for the interaction of DND with FA is proposed.