High antibacterial properties of DLC film doped with nanodiamond

DLC films are used in many applications, and nanoparticles are being used as dopant materials in a large number of films. In this investigation, DLC films doped with nanodiamond were deposited on Ti6Al4V substrates. Detonation nanodiamond (DND) was stirred in hexane with a sonicator at 750 W to obtain a suspension, which was introduced by an evaporation process into a PECVD reactor to produce DLC films continuously doped with nanoparticles. An amorphous silicon interlayer was used before depositing the DLC on the Ti6Al4V substrate. Raman spectroscopy results showed films with hydrogen contents around 22%. A scratch test on the Ti6Al4V alloy showed critical loads close to 19 N, and corrosion resistance measured via potentiodynamic polarization was improved with doped DLC over that of the bare substrate. An antibacterial test was carried out with Gram-negative Escherichia cell, showing antibacterial activity close to 95% 6 h after direct contact with the film. This result suggested that DLC is an excellent material for biomedical purposes. After 18 h of direct contact with the doped DLC film, antibacterial activity close to 25% was observed, which suggested that nanodiamonds are able to maintain their antibacterial properties and produce damage to E. coli cells.