Reply to the “Letter to the Editor” by Morfeld et al.

Dear Editor,

Morfeld et al. stated in the “Letter to the Editor” that the slicing technique (~80 nm) for TEM analysis reduces the size of particle agglomerates located in the treated tissue/compartment. We are aware of the fact that cutting very thin slices out of tissue with particles will lead in a lot of cases to only tangential cuts of the particles. Therefore, the real size of the particles will be bigger than measured. This is especially true the bigger the particles are. Consequently, the determination of agglomerate diameters based on TEM analysis would lead to a bias, resulting in lower average agglomerate diameters than originally existing. However, in our paper (Creutzenberg et al., 2012), TEM analysis was used to follow the temporal alteration of particle agglomerate diameters and to obtain information whether nanoscaled particle agglomerates tend to increase or to disintegrate. This question can be well investigated using TEM analysis. Though mean average diameters of originally existing agglomerates cannot be derived from this, we presented the results as measured under the conditions stated in the material and methods section. This will allow comparing these TEM analysis results to other publications (e.g. Schaudien et al., 2012).

Declaration of interest

The authors report no conflicts of interest.