Antibacterial activity of silver surface modified polyethylene terephthalate by filtered cathodic vacuum arc method

Silver (Ag) modified polyethylene terephthalate (PET) surface by filtered cathodic vacuum arc (FCVA) technique is performed. The structure and component of the modified surface are characterized by X-ray photoelectron spectroscopy (XPS) and the cross-section is observed by scanning electron microscope (SEM). The results show that a 4–5 μm silver layer is formed on the PET surface. The results of the colony forming units (CFU) plate counting in vitro indicate that the adhesion of Staphylococcus epidermidis (SE) to PET is suppressed by silver coating. The adhesion efficiency of SE on the modified surface is only about 25% of the untreated PET surface. The interfacial free energy of adhesion (ΔFAdh) of SE onto the silver coating deposited on PET is + 8.6 mJ/m2, and this means that bacterial adhesion is energetically unfavorable. The releasing rate of silver ions from the PET modified by silver FCVA is 0.12 μg/mL during 2 h. The release of antibacterial silver ion may be another reason of less SE adhered to the PET surface modified by Ag FCVA. The release of lactate dehydrogenase (LDH) was used to evaluate the immediate toxicity of the PET modified by silver FCVA method. It is showed that this modified surface has low toxicity.