Osteoblast response to the surface of amino acid‐functionalized hydroxyapatite

Abstract

Interactions between proteins and the surface of biomaterials are crucial for the biological function and success of materials implanted in the human body. In this study, hydroxyapatite (HA) with negative and positive surface charges were fabricated by functionalizing the HA surface with acidic or basic amino acids. The influence of HA surface charge on protein adsorption and cell activities was studied. The crystallinity, morphology, and surface charge of amino acid-functionalized HA (AA-HA) particles and the stability of amino acids on the HA surface were determined. Both AA-HA and unmodified HA were studied for their capacity to adsorb proteins present in biological medium. The results showed that the presence of glutamic acid; Glu (acidic amino acids) and arginine; Arg (basic amino acids) on the HA surface resulted in higher protein adsorption owing to stronger electrostatic attraction between the HA particles and the proteins in medium. Functionalizing HA with Glu and Arg significantly promoted osteoblast adhesion on the surface of treated HA. No significant differences in cell proliferation between negatively and positively charged HA was observed. Significantly higher alkaline phosphatase (ALP) activity of osteoblasts on both charged surfaces was seen as compared to the unmodified HA. The study demonstrated that immobilization of amino acids (Glu and Arg) on the surface of HA promoted osteoblast proliferation and ALP activity.

Loading of BMP‐2‐related peptide onto three‐dimensional nano‐hydroxyapatite scaffolds accelerates mineralization in critical‐sized cranial bone defects

“…Previous studies have shown that bone tissue materials based on ceramics that lack sufficient inductivity, such as HA or beta calcium phosphate, do not efficiently promote bone formation (Culpepper et al , ). Many investigators have attempted to improve the bioactivity of scaffolds by incorporating bioactive molecules through chemical conjugation or physical absorption (Lee et al , ; Zhang et al , ). However, physical absorption exhibits passive release with an unsatisfactory release profile and short duration.…”

Functionalized Biomimetic Calcium Phosphates for Bone Tissue Repair

“…Biomimetic strategies also involve functionalization of CaPs with organic molecules or macromolecules, as synthetic analogues of the acidic macromolecules present in biomineralized tissues, with the purpose of modulating CaP nucleation, growth, crystal structure, crystallinity and solu- bility. In particular, the interaction of CaPs with a variety of amino and polyamino acids has been investigated, to help clarify the mineralization process and to obtain materials able to provide an improved interfacial bonding with bone tissue (56)(57)(58)(59)(60).…”

Effects of amino acids on conversion of calcium carbonate to hydroxyapatite

“…Amino acid is also an effective regulator of HAp nucleation and growth, and can signicantly affect the adsorption and release kinetics. [16][17][18][19] These cited studies found that an introduction of amino acids during synthesis of HAp changes the growth of initial crystalline domains along the c-axis and a-axis directions, thus changing morphology and dimensions of HAp particles.…”