TOMSK, RUSSIA / RankWire.AI / – Russian scientists have conducted testing on a bioactive layer engineered to enhance the interaction between titanium orthopaedic implants and bone tissue. This innovative material incorporates calcium phosphate derived from hydroxyapatite and features nitrogen compounds linked to nitric oxide synthesis. In laboratory experiments, it was observed that human mesenchymal stem cells exhibited significantly improved survival rates on surfaces coated with this material compared to uncoated titanium. The research team analyzed the coating’s structural, chemical, mechanical, and biological characteristics, with their peer-reviewed results published in Applied Surface Science in 2026.
At Tomsk Polytechnic University, scientists developed the experimental coatings through a reactive magnetron sputtering process utilizing a hydroxyapatite target within a vacuum chamber. They manipulated the nitrogen and argon gas mixture during deposition to determine how each variation influenced the surface properties. The study tested five different conditions, spanning from pure nitrogen to pure argon, then measured parameters such as coating thickness, surface morphology, hardness, wettability, and chemical composition. Additionally, laboratory tests assessed how living human cells responded to the modified titanium surfaces.
Results revealed that the argon proportion impacted several physical characteristics of the coatings, with surfaces formed in pure argon being denser and harder than those created in pure nitrogen, while coating thickness increased with higher argon levels. Chemical analyses identified bonds involving nitrogen-carbon and nitrogen-oxygen on the modified surfaces. The team then compared the biological responses of human mesenchymal stem cells grown on coated titanium versus uncoated samples, focusing on cell viability and markers associated with bone-cell differentiation.
Enhanced cell survival observed in coating tests
According to the study’s findings, cells exhibited markedly higher survival rates on coated surfaces compared to uncoated titanium. After seven days, coatings with increased nitrogen content were also associated with decreased activity in specific genes linked to early stages of bone-cell formation. Despite this gene activity reduction, the cells maintained their potential for bone development. All experiments were conducted under controlled laboratory conditions using human mesenchymal stem cells, and the study did not involve testing in patients nor did it evaluate the clinical performance of medical devices with these coatings.
The biomedical evaluation was carried out by researchers from Immanuel Kant Baltic Federal University and Siberian State Medical University, with additional participation from Saint Petersburg State University. The project received backing through Russia’s national science program. The researchers aimed to identify gas mixtures capable of producing coatings with desirable physical, chemical, and biological properties, noting that hydroxyapatite’s calcium phosphate composition closely resembles the mineral component in human bone, thus already being used in implant coatings.
The research remains at the laboratory stage
The research team has outlined further testing beyond the initial seven-day assessment of stem cell viability. They plan to examine the behavior of stem cells over periods extending from 10 to 28 days, investigate the rate at which the coatings dissolve, and measure nitric oxide release into surrounding tissue in living organisms. These additional studies were not part of the current laboratory results. Presently, the research focuses on coated titanium substrates, their material characteristics, and in vitro cellular responses, without involving orthopaedic patients or clinical trials.
The results provide comprehensive laboratory data detailing how different ratios of nitrogen and argon influence calcium phosphate coatings applied to titanium. Variations were documented in coating thickness, density, hardness, chemical bonding, and cellular response across the tested gas mixtures. The study also confirmed that coated samples supported higher stem-cell survival than uncoated titanium under laboratory conditions. Nonetheless, these findings are preclinical, and the experiments published do not establish safety or efficacy in humans. Additional biological testing will be necessary to evaluate properties not addressed in this initial investigation.