Bacterial adhesion to toroidal nano-structures from poly(styrene)-block-poly(tert-butyl acrylate) diblock copolymer thin films

Nano-structured thin films with protruding PtBA nanodomain structures were obtained from the deposition, spin-coating, self-assembly and annealing of the diblock copolymer poly(styrene)-block-poly(tert-butyl acrylate) (PS-b-PtBA). The topography has been documented by atomic force microscopy. The sacrificial removal of the PtBA block from these thin film structures after UV irradiation yielded surfaces with 5/7 segmented polystyrene (PS) toroids of 100–150 nm diameter. These polymeric materials (as well as the corresponding homopolymeric materials derived from PS and PtBA) were incubated with Staphylococcus aureus cells. Live and dead cell numbers were determined in replicate trials by fluorescence microscopy after the cells were stained for viability. S. aureus formed colonies of 5–200 cells on the nanodomain and toroid-containing surfaces as assessed by AFM, but only attached sparsely as single cells onto a planar PtBA surface. Cell viability and adhesion was found to be influenced by a combined effect of the surface hydrophilicity and topography. The results demonstrate a synthetic route to produce polymeric surfaces with nano-toroids which are capable of modifying bacterial adhesion.