Exposure to TiO2 nanoparticles increases Staphylococcus aureus infection of HeLa cells.
BACKGROUND
Titanium dioxide (TiO2) is one of the most common nanoparticles found in industry ranging from food additives to energy generation. Approximately four million tons of TiO2 particles are produced worldwide each year with approximately 3000 tons being produced in nanoparticulate form, hence exposure to these particles is almost certain.


RESULTS
Even though TiO2 is also used as an anti-bacterial agent in combination with UV, we have found that, in the absence of UV, exposure of HeLa cells to TiO2 nanoparticles significantly increased their risk of bacterial invasion. HeLa cells cultured with 0.1 mg/ml rutile and anatase TiO2 nanoparticles for 24 h prior to exposure to bacteria had 350 and 250 % respectively more bacteria per cell. The increase was attributed to bacterial polysaccharides absorption on TiO2 NPs, increased extracellular LDH, and changes in the mechanical response of the cell membrane. On the other hand, macrophages exposed to TiO2 particles ingested 40 % fewer bacteria, further increasing the risk of infection.


CONCLUSIONS
In combination, these two factors raise serious concerns regarding the impact of exposure to TiO2 nanoparticles on the ability of organisms to resist bacterial infection.
Department of Materials Science and Engineering, Stony Brook University, Stony Brook, NY, USA.
Yan
Y
Xu
Department of Bioengineering, Lehigh University, Bethlehem, PA, USA.
Ming-Tzo
MT
Wei
Department of Bioengineering, Lehigh University, Bethlehem, PA, USA.
H Daniel
HD
Ou-Yang
Department of Oral Biology and Pathology, School of Dental Medicine, Stony Brook University, Stony Brook, NY, USA.
Stephen G
SG
Walker
Department of Physiology and Biophysics, Stony Brook University, Stony Brook, NY, USA.
Hong Zhan
HZ
Wang
Department of Physiology and Biophysics, Stony Brook University, Stony Brook, NY, USA.
Chris R
CR
Gordon
Yeshiva University High School for Girls, Hollis, NY, USA.
Shoshana
S
Guterman
University of California at Los Angeles, Los Angeles, CA, USA.
Emma
E
Zawacki
Stern College for Women, New York, NY, USA.
Eliana
E
Applebaum
Department of Physiology and Biophysics, Stony Brook University, Stony Brook, NY, USA.
Peter R
PR
Brink
Department of Materials Science and Engineering, Stony Brook University, Stony Brook, NY, USA.
Miriam
M
Rafailovich
Department of Materials Science and Engineering, Stony Brook University, Stony Brook, NY, USA. taniamironova@gmail.com.
Tatsiana
T
Mironava
D000900:Anti-Bacterial Agents / Q000009:adverse effects; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D006367:HeLa Cells; D006801:Humans; D053768:Metal Nanoparticles / Q000009:adverse effects*; D010316:Particle Size; D013203:Staphylococcal Infections / Q000139:chemically induced*; D013211:Staphylococcus aureus / Q000187:drug effects*; D014025:Titanium / Q000009:adverse effects*
D000900:Anti-Bacterial Agents; C009495:titanium dioxide; D014025:Titanium
Bacterial infection; HeLa cells; Nanoparticles; Nanotoxicology; Titanium dioxide