Bone mineral and interface properties of system calcium phosphate/aqueous solution

Author(s)

Sergio Bertazzo

• Document type: Doctoral Thesis
• Press: Campinas, SP.
• Institution: Universidade Estadual de Campinas (UNICAMP). Instituto de Química
• Defense date: 2007-08-20

Examining board members

Celso Aparecido Bertran; Gloria Dulce de Almeida Soares; Marisa Masumi Beppu; Edvaldo Sabadini; Italo Odone Mazali

• Advisor: Celso Aparecido Bertran

Abstract

Calcium phosphates have good biocompatible properties and are similar in composition to the bone mineral of vertebrates. Owing to these properties, calcium phosphates have been extensively studied, yet a complete consensus on the characteristics of these materials is hitherto absent. In this work we have studied some of the surface phenomena that take place when calcium phosphates are immersed in aqueous solutions, and sought to offer a comprehensive characterization of the bone mineral. Results show that the bone mineral modifies its composition and crystallinity only up to the sixth month of age for the animals studied. As for bone nanostructure, results show that these are formed from collagen fibers coated with bone mineral. Our studies on the surface properties of calcium phosphates have demonstrated that their surface transforms into CaHPO4 when immersed in aqueous solutions. Calcium phosphate surface modification and the formation of a new equilibrium between this new surface and aqueous solutions account for the distinctive characteristics presented by calcium phosphates in aqueous solutions with pH between 6.0 and 7.4. Knowledge of the processes that happen to calcium phosphates immersed in aqueous solutions is of utmost importance for an complete understanding of biocompatible processes characteristic of these materials (AU)