In order to calculate the dose for nanoparticles (NP), (i) relevant information\nabout the dose metrics and (ii) a proper dose concept are crucial. Since the appropriate\nmetrics for NP toxicity are yet to be elaborated, a general dose calculation model for\nnanomaterials is not available. Here we propose how to develop a dose assessment model\nfor NP in analogy to the radiation protection dose calculation, introducing the so-called\nââ?¬Å?deposited and the equivalent doseââ?¬Â. As a dose metric we propose the total deposited NP\nsurface area (SA), which has been shown frequently to determine toxicological responses\ne.g. of lung tissue. The deposited NP dose is proportional to the total surface area of\ndeposited NP per tissue mass, and takes into account primary and agglomerated NP.\nBy using several weighting factors the equivalent dose additionally takes into account\nvarious physico-chemical properties of the NP which are influencing the biological\nresponses. These weighting factors consider the specific surface area, the surface textures,\nthe zeta-potential as a measure for surface charge, the particle morphology such as the\nshape and the length-to-diameter ratio (aspect ratio), the band gap energy levels of metal and metal oxide NP, and the particle dissolution rate. Furthermore, we discuss how these\nweighting factors influence the equivalent dose of the deposited NP.
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