Can nanomaterials enter the human body via the gastro-intestinal tract?
Yes, but only very small amounts of nanomaterials can be taken up via the gastro-intestinal tract by penetrating tissue deeper layers and entering the blood stream. However, the overall amount is very low and most of the particles are not synthetic ones. Many minerals and other substances have a size range of about 1 to 100 nm, thus, our gastro-intestinal tract is very well adapted to handle such materials.
- Further information on this topic is provided in the body barriers article “nanoparticles and the gastro-intestinal tract”!
Can nanoparticles enter the body via the lung?
Yes, it has been shown that ultrafine dust particles including nanoparticles can cross the ultrathin tissue barrier in the lung thereby entering the body via the bloodstream. However, less than one-thousandth of the initially inhaled particles actually end up in the bloodstream so the amount is negligible.
- Further information on this topic is provided in the body barriers article “nanoparticles and the lung“!
Can nanoparticles pass the placental barrier?
Yes this is possible. But the mechanism and what physicochemical properties of the nanoparticles affect the transfer is still largely unknown and the subject of current research.
Please refer to the cross-cutting article “Nanoparticles at the placental barrier“.
Can nanoparticles pass the blood-brain barrier?
Researchers are trying to shed light on open issues such as these. In spite of intensive efforts that serve to develop treatments for e.g. brain tumors which cannot be treated otherwise, it seems to be rather difficult so far to intentionally force sufficient quantities of nanoparticles over the blood-brain barrier. In view of this fact, it is rather improbable that nanoparticles other than the specially tailored ones will pass the barrier unintentionally.
For all that, it was found that nanoparticles can reach the brain by passing through the olfactory nerve. All experimental results obtained so far, however, indicate that the quantity of nanoparticles reaching the brain either via the blood-brain barrier or via the olfactory nerve in the olfactory epithelium of the nose is very small. Further research remains to be done to solve these issues.
- More information on nanoparticles and the brain can be found in the cross-cutting section at “nanoparticles at the blood-brain barrier” !!