Figure 2.

Photoactivation of the ethanol extract of Skeletonema marinoi induces a dose-dependent inhibition of Staphylococcus aureus biofilm formation. S. aureus planktonic cells were treated with control medium (Control), bleach, or increasing concentrations of Skm ethanolic extract under both dark conditions (upper line) or white light illumination (total fluence of 25 J·cm⁻², lower line). The “Medium” column indicates a negative control with no bacteria. Following a 24-h incubation at 37 °C, the residual biofilm was stained with crystal violet (CV) and quantified through UV-Vis spectrophotometry at 595 nm after CV solubilization with acetic acid. All experiments were performed in triplicate.