title: Reduced bacterial growth and increased osteoblast proliferation on titanium with a nanophase TiO2surface treatment.
abstract: BACKGROUND
  The attachment and initial growth of bacteria on an implant surface dictates the progression of infection. Treatment often requires aggressive antibiotic use, which does not always work. To overcome the difficulties faced in systemic and local antibiotic delivery, scientists have forayed into using alternative techniques, which includes implant surface modifications that prevent initial bacterial adhesion, foreign body formation, and may offer a controlled inflammatory response.
  
  
  OBJECTIVE
  The current study focused on using electrophoretic deposition to treat titanium with a nanophase titanium dioxide surface texture to reduce bacterial adhesion and growth. Two distinct nanotopographies were analyzed, Ti-160, an antimicrobial surface designed to greatly reduce bacterial colonization, and Ti-120, an antimicrobial surface with a topography that upregulates osteoblast activity while reducing bacterial colonization; the number following Ti in the nomenclature represents the atomic force microscopy root-mean-square roughness value in nanometers.
  
  
  RESULTS
  There was a 95.6% reduction inStaphylococcus aureus(gram-positive bacteria) for the Ti-160-treated surfaces compared to the untreated titanium alloy controls. There was a 90.2% reduction inPseudomonas aeruginosa(gram-negative bacteria) on Ti-160-treated surfaces compared to controls. For ampicillin-resistantEscherichia coli, there was an 81.1% reduction on the Ti-160-treated surfaces compared to controls. Similarly for surfaces treated with Ti-120, there was an 86.8% reduction inS. aureus, an 82.1% reduction inP. aeruginosa, and a 48.6% reduction in ampicillin-resistantE. coli. The Ti-120 also displayed a 120.7% increase at day 3 and a 168.7% increase at day 5 of osteoblast proliferation over standard titanium alloy control surfaces.
  
  
  CONCLUSIONS
  Compared to untreated surfaces, Ti-160-treated titanium surfaces demonstrated a statistically significant 1 log reduction inS. aureusandP. aeruginosa, whereas Ti-120 provided an additional increase in osteoblast proliferation for up to 5 days, criteria, which should be further studied for a wide range of orthopedic applications.
authors.affiliation: Department of Chemical Engineering, Northeastern University, Boston, MA, USA.
authors.forename: Garima
authors.initials: G
authors.lastname: Bhardwaj
authors.affiliation: Department of Chemical Engineering, Northeastern University, Boston, MA, USA.
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Webster
mesh_terms: D001419:Bacteria / Q000187:drug effects / Q000254:growth & development*; D001422:Bacterial Adhesion / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D015169:Colony Count, Microbial; D004926:Escherichia coli / Q000187:drug effects / Q000254:growth & development; D006801:Humans; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D010006:Osteoblasts / Q000166:cytology*; D011550:Pseudomonas aeruginosa / Q000187:drug effects / Q000254:growth & development; D013211:Staphylococcus aureus / Q000187:drug effects / Q000254:growth & development; D013499:Surface Properties; D014025:Titanium / Q000494:pharmacology*
chemical_list: C009495:titanium dioxide; D014025:Titanium
keywords: electrophoretic deposition; infection; nanotopography; titanium dioxide