Stainless steel is widely used in surgical medicine: it is used in the manufacture of medical equipment such as coronary stents, hip prosthesis stems and intervertebral disc replacement prostheses, and in various surgical instruments such as scalpels and forceps, as well as operating tables.
As a material, however, stainless steel is not without defects. Over time, stainless steel implants can cause allergic and toxic reactions and be rejected by the body; in unhygienic surgical environments, steel may not adequately resist the accumulation of harmful bacteria.
For years, scientists have been experimenting with ways to improve the efficiency of stainless steel by using special coatings or by modifying its chemistry, or even the molecular structure of its surface. While they have made improvements, they have complex intrinsic limitations.
To date, no simple, effective and cost-effective solution has been found. However, thanks to their expertise acquired in the work of other biomedical metals, scientists from the Faculty of Dentistry of the University of Montreal and one of their colleagues from the Department of Chemistry have developed a way to modify the surface of the stainless steel by creating a set of pores at the nanoscale.
Other generalized applications possible
The new process, which could have widespread applications in the medical and other industrial sectors, offers the prospect of improved tolerance of stainless steel by the body and increased control of bacterial infections in hospitals. The results of this research are detailed in a study published in Colloids and Surfaces B: Biointerfaces.
"The advantage of this process lies in its simplicity and ability to increase cell response while limiting bacterial overgrowth," says study supervisor Antonio Nanci, an anatomist in cell biology and director of the Research Laboratory on Cellular Biology. calcified tissues and biomaterials.
"Given its antibacterial properties, this process avoids the use of antibiotics and chemicals. It is simply based on the physicochemical interaction between steel and bacteria, which is quite unique and encouraging. It could be a new tool to fight against bacterial resistance to antibiotics, says Antonio Nanci. Everything that is made of stainless steel in hospitals, be it door handles, instruments or operating tables, could be treated in this way. This will prevent the spread of bacteria. For medical implants, the surface-modified stainless steel will facilitate tissue regeneration around implants and help the body tolerate them better. "
A discovery due to a Spanish scientist
The authors of this study relied on work by Alejandra Rodriguez-Contreras, a postdoctoral fellow from Barcelona, who is looking for ways to make antibacterial surfaces. A job that is usually complex and laborious. "Alejandra did not think it would be possible to do it easily with stainless steel, but she tried and it worked," recalls Antonio Nanci. She ran into my office and shouted, "It works, it works!" "The Spanish scientist adapted a technique that is used for the electroplating of metals using an unusual mixture of chemical compounds.
"In fact, we have taken over the simple methods we designed for titanium dental implants. We adapted them to stainless steel and it worked very well, says Antonio Nanci. Stainless steel is very resistant to chemical treatments and many scientists have tried over the years to make its surface functional. It's a difficult material to handle, but we've cracked it. "
Antonio Nanci believes that the process his group developed to modify the surface of the metal - what he calls nanocavitation - is of medical interest, but that it can also be used in other industries to improve resistance to friction, strengthen the adhesion of coatings and paints or treat the fermentation tanks of certain foods and beverages, such as beer.
This article has been republished from materials provided by the University of Montreal. Note: material may have been edited for length and content. For further information, please contact the cited source.
Chemical nanocavitation of surfaces to enhance the utility of stainless steel as a medical material. Alejandra Rodriguez-Contreras, Dainelys Guadarrama Bello, Sam Flynn, Fabio Variola, James D. Wuest, Antonio Nanci. Colloids and Surfaces B: Biointerfaces Volume 161, 1 January 2018, Pages 677-687 https://doi.org/10.1016/j.colsurfb.2017.11.051.