Antibacterial activity of Cu ions released from 316L-Cu antibacterial stainless steel

Zhang Dan; Ren Ling; Yang Ke; Zhang Yang; Xue Nan; Guo Yan

doi:10.3969/j.issn.2095-4344.2015.25.018

Abstract：BACKGROUND:316L-Cu antibacterial stainless steel is made by adding a certain amount of copper into the stainless steel fol owed by a special heat treatment to uniformly disperse copper-rich precipitates in stainless steel substrate, thereby harvesting the antibacterial properties. OBJECTIVE:To evaluate the antibacterial activity of the Cu ions released from 316L type Cu-bearing antibacterial stainless steels against Porphyromonas gingivalis, thereby providing biomedical evidence for its clinical application. METHODS:The medical 316L stainless steel samples at a surface area to volume ratio of 0.1 cm2/L were soaked in simulated body fluids at 37 ℃ for 1-10 days. A graphite furnace atomic absorption spectrophotometer was employed to detect the amount of Cu release in the simulated body fluids each day and then the rate of Cu release per day could be determined. The antibacterial activities of the steel samples were evaluated by a standard film-covered method under a scanning electron microscope. RESULTS AND CONCLUSION:The daily Cu releasing amount from the 316L-Cu stainless steel within 10 days was significantly higher than that of 316L stainless steel, and al the values remained nearly constant. With time, the sterilizing rate of 316L-Cu stainless steel was gradual y increased, and reached 100%until the 10th hour. Porphyromonas gingivalis showed some morphological changes at 3 hours after treated with 316L-Cu stainless steel, appeared with cleavage at 6 hours, and mostly disintegrated into pieces at 9 hours. The results indicated that the 316L-Cu antibacterial stainless steel showed excel ent antibacterial property against Porphyromonas gingivalis, slowly release Cu irons, and alter the surrounding microenvironment, which is a highly promising biomaterial and has good clinical value.