Thyme oil and its monoterpenoids as natural antibacterial compounds of sodium alginate/(hyaluronic acid) coatings on austenitic stainless steel substrates - replication data

Novel antibacterial sodium alginate-based coatings with the addition of thyme oil and their monoterpenoids (carvacrol, thymol) were obtained in one-step and two-step electrophoretic deposition (EPD) processes on stainless steel substrates. An ecological and economical approach using a larger amount of distilled water instead of ethanol and the addition of hyaluronic acid in the dispersed system used for EPD, while maintaining the high adhesion strength, was developed. The highest adhesion to the chemically etched substrate was detected for coatings deposited in two-steps using a sodium alginate inner layer and then an outer layer enriched with a bactericide agent and/or hyaluronic acid. The microstructure of the coatings comprises oil droplets in the polymeric matrix. The mechanisms of interactions between the molecules of the embedded thyme-derivatives phytochemicals and the polymer chains were proposed. The surfaces of the coatings were hydrophilic and their roughness was several times
higher than that of the steel substrates. The coated samples demonstrated an improvement in the corrosion resistance of the substrates in Hanks’ solution.
All tested coated samples exhibited antimicrobial activity and antibiofilm properties. The potential cytotoxicity of the surfaces was confirmed. The developed coatings are promising for protecting temporary steel bone implants against bacterial biofilm formation.