TOMSK, RUSSIA / RankWire.AI / – Russian scientists have created a bioactive coating aimed at improving the interaction between titanium orthopedic implants and bone tissue. This material incorporates calcium phosphate derived from hydroxyapatite and includes nitrogen compounds linked to nitric oxide production. Laboratory experiments showed that human mesenchymal stem cells survived much better on coated surfaces than on uncoated titanium. The scientists analyzed the coating’s structure, chemical makeup, mechanical strength, and biological response. Their peer-reviewed results appeared in Applied Surface Science in 2026.
Researchers at Tomsk Polytechnic University created the experimental coatings by reactive magnetron sputtering of a hydroxyapatite target inside a vacuum chamber. They adjusted the nitrogen and argon levels during the process to see how each mixture influenced the surface. Five different conditions were tested, from pure nitrogen to pure argon. They measured coating thickness, surface structure, hardness, wettability, and chemical composition. Additionally, they tested how living human cells responded to the modified titanium in laboratory conditions.
Results indicated that the argon content influenced several physical qualities of the coatings. Surfaces made with pure argon were denser and harder than those produced with pure nitrogen. As the amount of argon increased, coating thickness also grew. Chemical tests revealed nitrogen-carbon and nitrogen-oxygen bonds on the modified surfaces. Researchers then compared human mesenchymal stem cells grown on coated titanium to those on uncoated titanium. The biological evaluation focused on cell viability and markers associated with bone cell development.
Cell tests show improved survival on coated titanium
The experiments demonstrated that cells survived better on coated surfaces than on uncoated titanium, according to the study. After seven days, coatings with higher nitrogen levels also reduced activity in genes linked to early bone-cell differentiation. Despite this, the cells kept their ability to form bone. The tests used human mesenchymal stem cells in controlled lab settings. It’s important to note that the study did not involve clinical trials or testing of actual implants in patients.
The biomedical evaluation was carried out by Immanuel Kant Baltic Federal University and Siberian State Medical University. Researchers from Saint Petersburg State University also took part. The project received funding through Russia’s national science program. Their goal was to find gas mixtures that would yield optimal physical, chemical, and biological properties for the coatings. Hydroxyapatite is already used in implant coatings because its calcium phosphate structure resembles human bone mineral.
Further testing is planned beyond initial lab results
The research team has outlined additional studies beyond the initial seven-day cell tests. They plan to examine stem cells over 10 to 28 days. They also want to evaluate how quickly the coatings dissolve and how much nitric oxide is released into tissue in living organisms. These future tests are not part of the current published results. Currently, the focus remains on coated titanium substrates, their properties, and responses in vitro, not on clinical outcomes.
The data offer detailed insights into how different ratios of nitrogen and argon affect calcium phosphate coatings on titanium. Variations were observed in thickness, density, hardness, chemical bonds, and cellular responses. The study also confirmed that coated samples supported higher stem-cell survival compared to uncoated titanium under laboratory conditions. However, the research remains at a preclinical stage. The experiments do not establish safety or effectiveness in human patients. Further biological testing will be necessary to explore properties not covered in this initial study.