Dithiothreitol solution

The anti-adhesive properties of coatings characterized by different NPs compositions (Ti-Ag-Cu and Mg-Ag-Cu) were tested. Uncoated circular cover glasses (VWR) were used as growth control (CTRL).
Briefly, a bacterial suspension of 1.0 × 10⁷ CFU/ml was prepared in Brain Heart Infusion broth (BHI, BioMeriéux) supplemented with 50% v/v human sterile serum (Merck). Thereafter, three discs per experimental condition (CTRL or Ti-Ag-Cu or Mg-Ag-Cu) were placed in a Petri dish and 100 µl of the bacterial suspension were dispensed on the surfaces of the coated or uncoated disks exploiting the surface tension of the liquid. Two independent tests were performed in triplicate for each strain. All the experimental procedures were carried out in the dark. After 30 and 120 minutes of incubation at 37°C, disks were rinsed twice with sterile saline to remove any non-adherent cells. Then, disks were placed in a sterile 5 ml tube containing 1 ml of 0.1% dithiothreitol solution (DTT, Sigma-Aldrich) (Drago et al., 2013 (link)) and sonicated at 45 kHz for 5 minutes to both mechanically and chemically dislodge bacteria. The eluates were then serially diluted and drop-plated (Herigstad et al., 2001 (link)) on tryptic soy agar (TSA, Sigma-Aldrich) plate and incubated at 37°C for 24 hours. Thereafter, viable colonies were counted and the number of colony forming units (CFU) was recorded.