Does lung surfactant promote disaggregation of nanostructured titanium dioxide?
OBJECTIVE
Nanostructured titanium dioxide (TiO2) is highly aggregated and agglomerated when inhaled. There are discussions regarding whether lung surfactant may promote the disaggregation of TiO2 particles. We investigated whether dipalmitoyl phosphatidyl-choline (DPPC), the main component of lung surfactant, can split the bonds between TiO2 aggregates and agglomerates.


METHODS
We calculated the energy required to split aggregates into primary particles and agglomerates into aggregates as well the energy of the interaction of a TiO2 surface with a DPPC bilayer. To test the calculations, we measured the particle size distribution of TiO2 suspensions in a pulmonary liquid model.


RESULTS
Calculated splitting energy between TiO2 aggregates was 1 J/m2 and 10 J/m2 between primary particles. The calculated interaction between DPPC and TiO2 was significantly weaker (0.05 J/m2). Calculations were shown to be in accordance with the measured particle size distribution of TiO2 suspensions in the pulmonary liquid model.


CONCLUSIONS
We conclude that lung surfactant does not promote the disaggregation of TiO2 agglomerates and aggregates.
Maier
Monika
M
Aerosil&Silanes, Degussa AG, Hanau, Germany. monika.maier@degussa.com
Hannebauer
Bernd
B
Holldorff
Henning
H
Albers
Peter
P
D015060:1,2-Dipalmitoylphosphatidylcholine / Q000737:chemistry*; D004396:Coloring Agents / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning; D049329:Nanostructures / Q000737:chemistry*; D010316:Particle Size; D011663:Pulmonary Surfactants / Q000737:chemistry*; D013535:Suspensions / Q000737:chemistry; D014025:Titanium / Q000737:chemistry*
D004396:Coloring Agents; D011663:Pulmonary Surfactants; D013535:Suspensions; C009495:titanium dioxide; D015060:1,2-Dipalmitoylphosphatidylcholine; D014025:Titanium