Polymeric antibiofilm coating comprising synergistic combination of citral and thymol prevents methicillin-resistant Staphylococcus aureus biofilm formation on titanium

Highlights: • The present study unveils synergism between citral and thymol in biofilm inhibition without altering growth of MRSA. • Polymeric antibiofilm coating comprising citral and thymol is fabricated on titanium. • Polymeric antibiofilm coating releases citral and thymol in a sustained manner and inhibits MRSA biofilm formation in vitro. • Polymeric antibiofilm coating is not toxic to human erythrocytes and PBMC. Biomaterial associated microbial infections are complicated and mostly lead to revision surgery or removal which are painful to the patients and quite expensive. These infections are difficult to treat with antibiotics as it is often related to biofilm formation. Methicillin resistant Staphylococcus aureus (MRSA) is the leading pathogen in biomaterial associated infections and well known to form biofilm on foreign materials. To reduce the risk of biomaterial associated infections, recent treatment strategies focus on modification of the implant surface to prevent the adhesion of bacteria. Antibiofilm coating is the effective approach than coating with antimicrobials as antibiofilm agents will not create selective pressure thereby excludes possibility of drug resistance. The current study identified and validated the synergistic antibiofilm activity of citral (CIT) and thymol (THY) by crystal violet quantification and microscopic analysis without alteration in growth and metabolic viability of MRSA. Polymeric antibiofilm coating with CIT + THY as active ingredients was formulated and coated on titanium surface by the process of spin coating. Fourier-transform infrared spectroscopy (FTIR) analysis confirmed the effective blending of polymeric formulation and the presence of CIT and THY. Atomic force microscopy (AFM) images revealed the homogenous coating and reduced surface roughness and thickness of the coating was measured by surface profilometer. Antibiofilm coating released CIT and THY in a sustained manner for 60 days. Antibiofilm coating effectively inhibited MRSA adherence in vitro and antibiofilm activity of coating was not affected by plasma conditioning. In addition, antibiofilm coating was non-hemolytic and non-toxic to PBMC. Thus, the current study demonstrated the effectual strategy to prevent biomaterial associated infections and proposes the prospective role of antibiofilm coating in clinical applications.