Reduction of bacterial adhesion on modified DLC coatings.

The high incidence of infections caused by the use of implanted biomedical devices, including catheters, bone fracture fixation pins and heart valves, etc. has a severe impact on human health and health care costs. Diamond-like carbon (DLC) films as biomaterial for medical devices have been attracting great interest due to their excellent properties such as low friction and chemical inertness. It has been demonstrated that the properties of DLC films can be further improved by the addition of selective elements into DLC films. In this paper Si- and N-doped DLC coatings with various silicon and nitrogen contents on 316 stainless steel substrates were prepared by a magnetron sputtering technique. Bacterial adhesion to the modified DLC coatings was evaluated with Pseudomonas aeruginosa (ATCC 33347) which frequently cause medical device infections. The results showed that the addition of N or Si in DLC coatings had a significant influence on bacterial adhesion. In general the modified DLC coatings with N or Si performed better than the pure DLC coatings in inhibiting bacterial adhesion. The bacterial adhesion mechanism on the modified DLC coatings was explained with thermodynamic theory.