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 th
