Effect of the presence of titania nanoparticles in the development of Pseudomonas fluorescens biofilms on LDPE

In this study the use of TiO2 nanoparticles in the preparation of active packaging film materials is investigated. High energy ball milling was used to uniformly disperse TiO2 nanoparticles within low density polyethylene, LDPE. Differential scanning calorimetry (DSC) and scanning electron microscopy (SEM) were used to characterize the nanocomposites. Growth of Pseudomonas fluorescens and subsequent bio-film formation on the surfaces of LDPE with and without TiO2 nanoparticles were studied with Atomic Force Microscopy (AFM) and viable cell counts. A set of samples placed either face down or face-up in microwell plates were subsequently immersed in P. fluorescens cultures and incubated for up to 48 h at 4 or 30 °C. AFM images showed that the presence of titania nanoparticles affects the growth, size, distribution and arrangement of bacteria on the polymer surfaces. Cell recovery and counting experiments revealed a reduction of at least 1-log (i.e. 90% reduction) in bacterial colony forming units per square centimeter (CFU cm-2) for the TiO2 nanofilled polymer compared to LDPE films, without photoactivation. In the presence of TiO2 nanoparticles, bacterial cells attached to the surfaces formed tight aggregates with apparently minor amounts of "extracellular polymer substances" (EPS) around them. This journal is

Effect of the presence of titania nanoparticles in the development of Pseudomonas fluorescens biofilms on LDPE Articles