Lobachevsky University chemists develop a new substance for bone implants
Researchers from the UNN Faculty of Chemistry have developed a new substance for bone implants, fluorapatite Ca₅(PO₄)₃F in which calcium atoms have been partially replaced with bismuth and sodium atoms. The element bismuth in the compound provides an antibacterial effect and helps to fight infections that threaten the patient’s body in the post-operative period. Sodium is responsible for the biocompatibility of the substance and helps it to integrate more actively into the bone. The substance composed of calcium, phosphorus, oxygen and fluorine is essentially a mineral which replicates the structure and composition of human bone tissue. The study has been published in the British journal Dalton Transactions.
Scientists say that the most common way to impart antibacterial properties to bone implants is to coat them with antibiotics, however, the drugs are washed out and get to other sites in the body instead of working properly on the implant surface. As shown by tests on human fibroblast culture, the Nizhny Novgorod researchers have managed to obtain a substance where the antimicrobial agent (bismuth) is firmly fixed in the crystal structure. In addition, the microstructural analysis has demonstrated that with a Ca/Bi/Na=8/1/1 ratio, the particles have a spheroidal shape, which facilitates their penetration into cells and increases the chances of the substance’s active effect at the intracellular level.
The research project started in 2018 in collaboration with scientists at Nanyang Technological University (Singapore). Today, researchers from the Privolzhsky Medical Research University in Nizhny Novgorod and the Kuban State Medical University also take part in the project.
The author of the study, Associate Professor of the UNN Analytical and Medicinal Chemistry Department Evgeny Bulanov comments: "We have been investigating compounds with the structure of apatite for about 13-14 years. This class of compounds is very diverse in terms of chemical composition, so we considered different applications of these materials: we explored the opportunities for their use as inorganic pigments and for binding radionuclides, but the most interesting and promising area of research was the study of bioceramic materials for bone tissue repair. We started with the hydroxyapatite proper and developed a cost-effective and easily scalable way of producing it. Our research has gradually focused on modifying its chemical composition and producing new forms of materials".
Researchers are planning to determine more precisely the optimal chemical composition of the compound for its clinical application. Currently, yet another modification of hydroxyapatite containing bioactive magnesium atoms is being developed.