Removal of surface by-products from sintered hydroxyapatite: Effect of a chelation treatment on fibronectin adsorption and cell adhesion

It was observed that fibronectin precipitates when deposited on hydroxyapatite (HA) ceramics. Fibronectin's known affinity for calcium and the composition of the ceramic itself suggested that calcium release could be the main cause of this aggregation effect. It was then decided to investigate the effect of a surface chelation treatment on fibronectin adsorption, and MG63 cell adhesion, onto porous ceramics of hydroxyapatite (HA), beta‐tricalcium phosphate (β‐TCP), and HA/TCP biphasic material (BCP). Those ceramics were immersed in an EDTA solution and the effect of this treatment on the material composition was assayed. X‐ray diffraction data showed the presence of α‐ and β‐TCP phases in HA and BCP materials, which were both completely removed by the chelation treatment in the case of HA. On BCP, α‐TCP was removed and β‐TCP partially dissolved. The TCP material, which was pure β‐TCP, underwent a mass loss, but no change in composition was observed. Adhesion of MG63 cells was overall higher on the fibronectin‐coated EDTA‐treated HA material, but was especially enhanced on EDTA‐treated HA. Changes in surface morphologies, as compared with the use of scanning electron microscopy, did not seem to be related to the effects observed. The EDTA treatment proved to be a very efficient way of removing by‐products of HA sintered materials, and thus enhancing the biocompatibility of the material. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2006