Synthesis, physicochemical characterization and antibacterial activity of carbon coatings

In recent years, significant interest has emerged in synthesizing new carbon materials with novel physicochemical properties for applications in regenerative medicine, particularly as antibacterial coatings for implants. A pronounced biological effect is observed for diamond-like carbon (featuring sp³- and sp²-hybridized carbon atoms) and linear-chain carbon (with sp¹-hybridization), which can be engineered due to carbon's polymorphic nature. This work presents the results of synthesizing carbon coatings at different assisting voltages and investigating their physicochemical properties and antibacterial activity. The coatings were characterized using Raman spectroscopy and X-ray fluorescence analysis. Antibacterial activity was assessed using lyophilized luminescent bacteria from the "Ecolume" system, where the bioluminescence intensity correlates with bacterial viability. Luminescence quenching indicates inhibition of bacterial enzymatic activity upon interaction with the coating surface. It was shown that an increase in the assisting voltage reduces the content of short chains of linear chain carbon (LCC) in the coatings. The coatings with high diamond phase content were found to be chemically inert when interacting with a biological environment. Modification of the coatings with silver ions enhances the antibacterial activity of the material. The maximum bactericidal effect is achieved when bacterial cells interact with a coating containing predominantly long chains of linear chain carbon.