Ab Initio investigation of mechanical, structural, energetic and electronic properties of calcium phosphates in bulk phase with substitutional dopants

• Grant number: 21/05697-6
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: September 01, 2021
• End date: August 31, 2023
• Field of knowledge: Physical Sciences and Mathematics - Chemistry - Physical-Chemistry
• Principal Investigator: Juarez Lopes Ferreira da Silva
• Grantee: Henrique Souza Marques
• Host Institution: Instituto de Química de São Carlos (IQSC). Universidade de São Paulo (USP). São Carlos , SP, Brazil
• Company: Universidade de São Paulo (USP). Instituto de Química de São Carlos (IQSC)
• Associated research grant: 17/11631-2 - CINE: computational materials design based on atomistic simulations, meso-scale, multi-physics, and artificial intelligence for energy applications, AP.PCPE

Abstract

Hydroxyapatite (HAP, Ca10(PO4)6(OH)2) is one of the main inorganic components of bones and teeth that has been extensively studied and employed in biomedical applications, such as bone grafting and dental implants, due to its biocompatibility and bioactivity. The crystallographic structure of this material allows for the addition of cationic and anionic ionic substituents in their three original sites: Ca^2+, PO4^3-, and OH^-. The ability to manipulate and control the number of substituents within the HAP lattice also enables the development of unique catalytic materials for various chemical reactions. For instance, Prof. Gustavo Paim Valença, School of Chemical Engineering -- UNICAMP, has explored HAP in the conversion of ethanol into new products. Despite a significant number of studies, the atomistic knowledge concerning the characteristics that influence its properties remains still unsatisfactory. Therefore, the goal of this project is to develop an ab initio investigation of the structural, energetic, and electronic properties of pure and doped hydroxyapatites via ionic substitution of the three sites in the HAP bulk phase, without interfering with the crystal's stoichiometric charge. All calculations will be performed using the density functional theory, as implemented by Vienna Ab initio Simulation Package (VASP), which is widely used by the scientific community. If the current scholarship proposal is granted, we plan to examine the influence of the same substituents in other calcium phosphates with different Ca/P ratios and analyze the effect on the physicochemical properties also caused by the change in the stoichiometry. In summary, the current project has the following goals: (I) to contribute to the formation of human resources at the undergraduate level by involving the student in the activities of the QTNano group, e.g., seminars, workshops, and the development of group work (soft skills); (II) to contribute to a better understanding of the structural, energetic, and electronic properties of hydroxyapatite-based compounds.(AU)