Antibacterial hydroxyapatite coatings for medical applications

Titanium coated by hydroxyapatite is extensively used in orthopedic implants. This is attributed to the advantages of titanium which offers desirable mechanical properties and to the biocompatibility of hydroxyapatite. Unfortunately, hydroxyapatite coatings are susceptible to bacterial infections. Therefore, in order to make such coatings viable in long-term applications such as orthopedic implants, they must have antibacterial properties which can be achieved via replacing calcium ions in hydroxyapatite structure with silver ions. Silver has received significant attention in research because it exhibits a broad spectrum of anti-microbial activities, as well as strong inhibitory and antifungal properties. Electrochemical deposition is the most frequently used technique to produce hydroxyapatite coatings and will form the focus of the proposed research.

A key aspect of the project is to determine the optimum parameters of the electrochemical process to achieve crystalline hydroxyapatite coatings without any phase decomposition and with appropriate mechanical properties. Additionally by determining these factors, the content of silver ions in hydroxyapatite structure can be controlled, which determines the biocompatability and antibacterial properties of the coatings.

The major drawback of experimental and theoretical research so far is that the majority of the works about silver-doped hydroxyapatite coatings have concentrated on their antibacterial and biocompatible properties rather than on mechanical behavior. As a consequence, the mechanical properties of electrodeposited coatings have yet to be studied systematically and conclusively. This project concentrates not only on the evaluation of the antibacterial and biocompatible properties of coatings, but also on the measurement of the hardness and Young’s modulus of such coatings. In addition, the experimental study is intertwined with predictive modeling studies of the mechanical properties of silver-doped hydroxyapatite coatings.

First supervisor

Prof. Dr. Yutao Pei

Co-supervisor

Dr. Patrick van Rijn

PhD student

Taraneh Mokabber