Title : Biofunctional coating of stainless steel surfaces with carvacrol- and eugenol-derived film using dielectric barrier discharge plasma: Aiming for suppression of biofilm formation and corrosion protection
Abstract:
Metallic biomaterials are extensively utilized in orthopedic and dental implants owing to their exceptional mechanical properties. However, careful consideration is essential when selecting materials for implant medical devices to ensure optimal performance in the biological environment. Apart from exhibiting good biocompatibility and chemical stability, the ideal material should also possess the ability to inhibit bacterial colonization on the implant. This study aims to investigate the application of a biofunctional coating derived from carvacrol (CDF) and eugenol (EDF) on stainless steel surfaces using atmospheric pressure plasma discharge, to enhance their electrochemical and biological properties. Film deposition was conducted in a specially designed dielectric barrier discharge reactor. The chemical structure and surface topography of the films were analyzed using infrared spectrometry and atomic force microscopy (AFM), respectively. The corrosion inhibition potential was evaluated using electrochemical impedance spectroscopy. Furthermore, the biofilm eradication efficacy of the coatings was tested against common human pathogens, namely Pseudomonas aeruginosa and Candida albicans. AFM analysis revealed that both CDF and EDF coatings effectively eliminated surface irregularities of the pristine substrate, resulting in a uniform surface devoid of defects and scratches. Infrared spectra indicated that the deposited films largely retained key functional groups of the monomers, such as hydroxyl and aromatic groups, which are essential for antibacterial and electrochemical activity. CDF demonstrated a reduction in biofilm growth rate of up to 44% for P. aeruginosa and 60% for C. albicans. Similarly, EDF exhibited suppression rates of up to 36% and 52% against these microbial strains, respectively. Moreover, the corrosion current density and corrosion rate were decreased by up to 35% upon application of the film coatings compared to the uncoated substrate. The surface treatment method employed in this study presents a promising alternative for steel substrates, as it enhances their electrochemical behavior and suppresses microbial biofilm formation.
