Self-organised nanoarchitecture of titanium surfaces influences the attachment of Staphylococcus aureus and Pseudomonas aeruginosa bacteria

Abstract

The surface nanotopography and architecture of medical implant devices are important factors that can control the extent of bacterial attachment. The ability to prevent bacterial attachment substantially reduces the possibility of a patient receiving an implant contracting an implant-borne infection. We now demonstrated that two bacterial strains, Staphylococcus aureus and Pseudomonas aeruginosa, exhibited different attachment affinities towards two types of molecularly smooth titanium surfaces each possessing a different nanoarchitecture. It was found that the attachment of S. aureus cells was not restricted on surfaces that had an average roughness (S a) less than 0.5 nm. In contrast, P. aeruginosa cells were found to be unable to colonise surfaces possessing an average roughness below 1 nm, unless sharp nanoprotrusions of approximately 20 nm in size and spaced 35.0 nm apart were present. It is postulated that the enhanced attachment of P. aeruginosa onto the surfaces possessing these nanoprotrusions was facilitated by the ability of the cell membrane to stretch over the tips of the nanoprotrusions as confirmed through computer simulation, together with a concomitant increase in the level of extracellular polymeric substance (EPS) being produced by the bacterial cells.

In Vitro Assessment of Early Bacterial Activity on Micro/Nanostructured Ti6Al4V Surfaces

“…The initial growing phase (2 h) showed important outcomes in colony organization on the rough surface and continued with an inferior tendency for the NTs and a poorer colony-forming capability on the flat material but with more consistent bacterial spreading. It is important to discuss that the promoted bacilli activity shown over the flat and rough experimental materials models evaluated here are consistent with previous works regarding the effect of surface roughness and the comparison of nanostructured morphologies versus microstructured materials [ 20 , 21 ]. The data suggest a greater affinity of P. aeruginosa with the rough and flat surface than the nanotubular one.…”

<p>Nanosilver/poly (DL-lactic-co-glycolic acid) on titanium implant surfaces for the enhancement of antibacterial properties and osteoinductivity</p>

“…12 After implantation, a rapid conditioning layer covers the surface of the implant and facilitates bacterial adhesion, forming a slimy extracellular polymeric substance (EPS) bacterial biofilm. 5,12,13 The EPS blocks the penetration of antibiotics and host immune cells, because the altered chemical microenvironment in the biofilm associated with nutrient and oxygen consumption causes some bacteria more resistant to antimicrobial and immune cells killing. 5,[14][15][16] Consequently, once a bacterial biofilm is produced, treating the infections is quite difficult, and bacteria in EPS biofilm form can be less susceptible to antibiotics or immune-reactive molecules than free-floating bacteria.…”

Copolymers enhance selective bacterial community colonization for potential root zone applications

“…Bacillus subtilis ATCC 6051 T and Pseudomonas fluorescens ATCC 13525 were obtained from the American Type Culture Collection (ATCC, USA). Bacterial stocks were prepared in nutrient broth (Oxoid) supplemented with 20% glycerol as previously described 49 , 50 . For each experiment, bacterial cultures were refreshed from stock on nutrient agar (Oxoid) and were collected at the logarithmic stage of growth.…”