what is the relation between size, shape of nanoparticle and its toxicity.it has particular range? what size nanoparticles or what shape nanoparticles is more toxic?
Your question is little broad I guess. What composition of nanoparticles you are interested in?. The article below is very useful
http://onlinelibrary.wiley.com/doi/10.1002/smll.200700595/abstract
This question has indeed touched on a fair portion of the field of nanotoxicology, from Shvedova's in vitro experiment in the early 2000s on the cytotoxicity of single walled carbon nanotubes, to the huge body of literature accumulated over the past decade on the toxicities of metal and metal oxide nanoparticles, to the toxicities of more exotic nanomaterials which have recently been developed for energy and devices applications.
Size does matter, as endocytosis favors the size range of ~20-50 nm for nanoparticle uptake through lipid membrane invagitation, which is a synergetic process involving proteins as well.
Shape does matter, as multlwalled carbon nanotubes have been shown to elicit an asbestos-like behavior in vitro, as shown in this paper:
http://www.nature.com/nnano/journal/v3/n7/full/nnano.2008.111.html
One reason for such toxicity, in addition to the generation of reactive oxygen species and membrane damage induced by the nanotubes, is the huge energy cost to shuttle one nanotube of 100 nm-1 um through the cell membrane (4 nm) and the consequent stress the uptake process must exert on the cellular machinery. To appreciate the physics side of such process you may refer to this paper:
http://www.nature.com/nnano/journal/v5/n8/abs/nnano.2010.141.html
More about shape, in addition to the usual spherical vs tubular morphologies of nanostructures graphene sheets are a 2D material and its toxicity is not only size dependent but also surface chemistry dependent (through changing reactivity and water suspendability of the sheets):
http://www.nature.com/nnano/journal/v8/n8/abs/nnano.2013.125.html
In addition to the factors mentioned above, the toxicities of nanoparticles also depend on the host cell type, as different cells possess different defense mechanisms against foreign substances. Cell media also matter, as they tend to shield the usually hydrophobic nanoparticle surfaces to form a so-called protein corona (i.e. physical adsorption). Surface coating with polymers (e.g. PEG) is another factor, which may render the nanoparticles antifouling against protein corona formation (i.e. through H-bonding and electrostatic repulsion) in biological environments, and such nanoparticles may escape from the recognition of the immune system and become "stealth" (for longer biocirculation). The ionic strength of the buffer/solvent also matters, as divalent and multivalent ions usually cause (especially metal) nanoparticles to aggregate and precipitate through coordination/chelation, thereby reducing the toxicity of the nanoparticles.
Lastly, for metal and metal oxide nanoparticles, ion release is a major mechanism for their cytotoxicity. Here shape and size are secondary factors. The origin of this is free radical chemistry plus biology.
Hope this helps.
sir thank you for your valuable information. I need to preapre least cytotoxic metal and metal oxide nanoparticles for biological application by incorporating it to the polymer matrix.so my actual doubt is which range of naoparticle is least toxic whether 10-50nm or 50-100nm , etc?.what shape and size i need to preapre?
CuO, ZnO and Ag can all be toxic, especially Ag. Au is perhaps the best pick in your case, with least cytotoxicity and easiest synthesis and detection (through surface plasmon resonance which you can see on a UV-Vis spectrophotometer). Shape and size-wise I would recommend spherical and 10-50 nm (easy for endo- and exocytosis). Ultrasmall Au nanoparticles of
There are several factors effect on nano-toxicity such as chemical composition of nanoparticle and functionalizing material, size of the particle, shape, specific cell type, etc.
Au, iron oxide, CaPO4, graphine based nanoparticles can be considered less toxic compared to Ag, Cd based nanoparticles. However functionalizing material plays a important role here.
Most of the time smaller the particle size, lesser the toxicity.
Shape of the particle has a impact on toxicity, however it mostly depends on the type of the nanoparticle.
Different nanoparticles has a different effect in different cell type.
Finally, nanotoxicity is a combination of several variations, like cytotoxicity, genotoxicity and immunotoxicity.
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