Surface Functionalization And Structuring By Electron Beam For Enhanced Biological Response The aim of this master thesis is evaluating how micro and nano-topography could influence bacterial behavior. Micro and nano-topographies were realized on different Titanium alloys substrates, in particular Ti-6Al-4V, Ti-15Mo and CP Titanium (Grade 2) have been investigated by means of Electron Beam Welding machine. Finally, the bacterial behavior was tested with Staphylococcus aureus (SA, commercial, multi-drug resistant, ATCC 43300) in order to compare the evolution of bacterial proliferation on different modified substrates. The first part of the work took place at the Institute of Materials Science, Joining and Forming (IMAT-TUGraz) in Graz, where were realized the different Titanium alloys surfaces.