Bacterial attachment and removal properties of silicon- and nitrogen-doped diamond-like carbon coatings

Qi Zhao, Xueju Su, Su Wang, Xiaoling Zhang, Parnia Navabpour, Dennis Teer

    Research output: Contribution to journalArticlepeer-review

    16 Citations (Scopus)


    Si- and N-doped diamond-like carbon (DLC) coatings with various Si and N contents were deposited on glass slides using magnetron sputter ion-plating and plasma-enhanced chemical vapour deposition. Surface energy analysis of the DLC coatings revealed that with increasing Si content, the electron acceptor gamma(+)(S) value decreased while the electron donor gamma(-)(S) value increased. The antifouling property of DLC coatings was evaluated with the bacterium, Pseudomonas fluorescens, which is one of the most common microorganisms forming biofilms on the surface of heat exchangers in cooling water systems. P. fluorescens had a high value of the gamma(-)(B) component (69.78 mN m(-1)) and a low value of the gamma(+)(B) component (5.97 mN m(-1)), and would be negatively charged with the zeta potential of -16.1 mV. The experimental results showed that bacterial removal by a standardised washing procedure increased significantly with increasing electron donor gamma(-)(S) values and with decreasing electron acceptor gamma(+)(S) values of DLC coatings. The incorporation of 2%N into the Si- doped DLC coatings further significantly reduced bacterial attachment and significantly increased ease of removal. The best Si- N-doped DLC coatings reduced bacterial attachment by 58% and increased removal by 41%, compared with a silicone coating, Silastic(R) T2. Bacterial adhesion strength on the DLC coatings is explained in terms of thermodynamic work of adhesion.

    Original languageEnglish
    Pages (from-to)377-385
    Number of pages9
    Issue number5
    Publication statusPublished - 2009


    • diamond-like carbon
    • Si-doped DLC
    • N-doped DLC
    • biofouling
    • nanostructured surfaces
    • adhesion
    • Pseudomonas fluorescens
    • XPS
    • STRESS


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