Antibacterial effects of silver–zirconia composite coatings using pulsed laser deposition onto 316L SS for bio implants

Bacterial invasion on biomedical implants is a challenging task for long-term and permanent implant fixations. Prevention of initial bacterial adherence on metallic implants is an important concern to avoid extracellular matrix (biofilm) secretion from bacteria that is resistant to antibacterial agents. In order to overcome this defect, recently, surface coatings such as zirconia (ZrO2) with higher smoothness have been shown to improve implants durability. In the present study, pulsed laser deposition (PLD) was used to deposit ZrO2 and silver (Ag)-ZrO2 composite coatings onto 316L stainless steel (316L SS). Phase purity, surface roughness and surface morphology, thickness of the coatings and elemental compositions of the coatings were analyzed using X-ray diffraction (XRD), atomic force microscopy (AFM) and scanning electron microscopy (SEM) with energy dispersive X-ray spectroscopy (EDS). Total viable count (TVC) and epifluorescence microscopy analysis were studied to evaluate antimicrobial efficiency of ZrO2 and Ag-ZrO2 composite coatings using gram negative (gram -ve) Escherichia coli (E.coli) and gram positive (gram +ve) Staphylococcus aureus (S.aureus). On the basis of the present study, it could be speculated that ZrO2 coatings exhibited antibacterial activity against only E.coli, whereas Ag-ZrO2 composite coatings showed superior activity against E.coli and S.aureus strains.