I've been studying toxicology of nanoparticles for a while and I read an article about uptake of nanoparticles. The author of the article said that nanoparticles can enter the cytoplasm but they can't enter the nucleus. I don't understant this process. Does anyone know this process?
First, particles are taken up by some kind of endocytosis (or phagocytosis in e.g., macrophages). To reach the nucleus they have to escape from the vesicles (endsomes/phagosomes) they are trapped in. After the release in the cytoplasm, they can connect to the nuclear pore complex with some defined and small peptid sequence (NLS as said above).
The reason is to protect nucleus. A macromolecule should have NLS (nuclear localization signal) to enter to nucleus. Although it seems very simple, conjugation of NLS to a macromolecule is not so easy. And also size and charge matters in this case. You can search for such studies (if present) by searching the internet.
Best regards
Thank you for your answer Mr. Malikmammadov. I didn't think about this way :) Thank you again.
First, particles are taken up by some kind of endocytosis (or phagocytosis in e.g., macrophages). To reach the nucleus they have to escape from the vesicles (endsomes/phagosomes) they are trapped in. After the release in the cytoplasm, they can connect to the nuclear pore complex with some defined and small peptid sequence (NLS as said above).
Nanoparticles as individual particles, are never entering a cell by phagocytosis. They are too small and will enter cells by endocytosis or by a process we called "adhesive interaction" passively (Se also publication be Wang et al., ACS Nano 6: 1251-59, 2012).
Phagocytosis applies to larger particles of a size of approx. 500nm upwards.
Thank you for answer Mr. Gehr. However, I tkink if nanoparticles can not be sonicated enough, they could be form ''agregate''. Then, won't they enter the cell by phagocytosis pathway ?
Tolga, please pay attention to Peter Gehr's answer. So far only small ( 5 nm) silica nanopartciles have been shown to enter the nucleus of different cells (for this please go to PubMed and find von Mickecz). I remember they did also work with other NP of the same size. Please Always consider these studies with care, since localisation in the nucleus can be easily an artefact due to technical shortcomings of the methods.
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