Abstract :Staphylococcus aureus is a gram-positive bacterium permanently present in the oral cavity, able to colonize polyurethane dental prostheses and to form biofilm. The bacterial action on the polymeric material results in the biodestruction of the polyurethane and in the formation of micro- and nano-particles. Electron microscopy, having a key role in the investigation of nanoparticles-bacteria interactions, points out that bacteria internalize polyurethane nanoparticles enveloped in membrane vesicles. In this work we discuss the uptake process of nanoparticles and the role of the bacterial cytoskeleton, important for the vesicular trafficking. We show images of membrane vesicles loaded with one or more polyurethane nanoparticles inside the bacterial cell, astride the membrane and out of the cell, in the extracellular medium.
This work opens new ways to the nanomedicine in the comprehension of bacterial secretion of membrane vesicles and their interactions with host cells, and raises new issues about the nanoparticles delivery guided by the dynamics of bacterial infections, and the related toxicological risks.