Developing a deposited calcium-phosphate layer on zirconia surface by chemical grafting of L-Serine molecules

• Published in: Journal of materials research and technology Vol. 28; pp. 66 - 77
• Main Authors: Sharifi, Sareh, Javadpour, Jafar, Rezaie, Hamidreza, Jamshidi, Masoud, Ghamarpoor, Reza
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.01.2024; Elsevier
• Subjects: Amino acid; Apatite calcium-phosphate formation (CPF); l-serine; Surface modification; Zirconia; Zirconia; l-serine; Surface modification; Apatite calcium-phosphate formation (CPF); Amino acid
• ISSN: 2238-7854
• DOI: 10.1016/j.jmrt.2023.11.285

Due to the proper mechanical properties and desirable aesthetic properties of zirconia, it is considered as a good candidate for replacement of metallic implants. In this study, zirconia was functionalized by l-serine amino acid to provide surface COOH/OH groups for calcium-phosphate formation (CPF) of hydroxyapatite and chemical bonding to bone tissue following implantation. Magnesia-partially stabilized zirconia (Mg-PSZ) discs were prepared and hydroxylated using hydrothermal process at 120 °C for different times to provide reactive hydroxyl groups. Thereafter, the discs were immersed in 0.01 mg/mL aqueous l-Serine solution at temperatures between 40 °C and 80 °C for different times and pH to graft l-Serine molecules on the zirconia surface. Afterward, the specimens were incubated in simulated body fluid (SBF) for 7 and 21 days. The results indicated that the grafting of l-Serine on the zirconia surface, at 80 °C in neutral pH, created negative charges. The hydroxyl apatite, on the surfaces grafted with l-Serine, started to nucleate and grow almost simultaneously after 7 days of exposure to alkaline pH. The soaking was continued for 21 days to form more uniform mineral apatite with developed surface wettability (i.e., contact angle of 18.3° ± 1.3). Herein, the absorption of calcium and phosphate ions caused the formation of hydroxyapatite nucleation and growth in 21 days.