Modulation of Hydroxyapatite Nanocrystal Size and Shape by Polyelectrolytic Peptides

Abstract

Interactions of synthetic peptides containing charged amino acids with hydroxyapatite (HAP) have been used as models of non-collagenous proteins’ interaction with bone’s minerals. While there is some knowledge of the affinities of these peptides with HAP, the effects of the type of charged peptide, peptidic molecular weight, and concentration on the crystal morphology have not been systematically investigated. Such knowledge could be useful for identifying the peptides ideal for in vitro or in vivo administration to customize crystal growth or for coating of implant surfaces for improving anchorage to neighboring bone tissue. This study used charged peptides of arginine (Arg), aspartate (Asp), glutamate (Glu), and lysine (Lys) to influence the HAP morphology. A systematic approach evaluated the polyelectrolytic peptides’ affinity for HAP as well as their effects on mineral nucleation/growth kinetics and crystal morphology. Negatively charged polymers (Asp, Glu) had greater affinity for hydroxyapatite than...