Ok, first up I would like to just say I am no nano scientist, I don’t spend all day looking through a hugely powerful microscope playing with atoms and such like, or trying to write my name on a hair shaft. So I will default my knowledge to anyone who does if they can read this in such big writing…..
Nano technology is a phrase that is used a lot. Mostly without any real thought as to what it is. Nano just means 10-9, it is just a numerical designation, nothing sinister.
So Nanometre purely means a size of 1-100 x 10-9 metres ie. 0.0000000001 metres ie. Really small. Technology is pretty much what you want it to be. Therefore nano-technology is anything small and sort of scientific/modern.
It really is that wide a definition, encompassing everything from Titanium Dioxide sunscreens to molecular modelling of carbon nano-tubes to surface coating the wings of space craft.
The biggest issue that occurs is that everything is grouped together under this all encompassing heading, with no differentiation based on uses, safety or composition. “Nano-technology is just bad”. It is not as simple as this by any stretch of the imagination.
You will also see that the EU are “regulating nanotechnology so it must be bad” in various blogs and such like. This is not strictly untrue, but it is a blurring of the definition. The EU are actually concerned with Nano Materials, not technology as a whole when applied to cosmetics, and it is more a notification so that they can keep an eye on the levels of use and applications as a means of gathering more information for further study ( as I understand it ).
So having spent a lot of time fairly recently trying to help get some interpretation within the new EU cosmetics legislation for nano materials I will start with that. For those that haven’t seen it the definition as listed in the legislation is :
“Nanomaterial means an insoluble or bio-persistent and intentionally manufactured material with one or more external dimensions, or an internal structure, on the scale of 1 to 100nm”
Which is quite a broad description, if you really think about it. A sheet that is 2 miles long by 2 miles wide, but only 50nm thick would be a nano material. Would this absorb through your skin or lungs ? Well, obviously not, this is a slightly silly example, but it is still correct and should make you think a little bit more about what the definition of nano-materials actually is and whether or not it applies to everything equally.
Back to discussing the description. One of the first things to take note of is “insoluble”. So any talk of things dissolving into the blood stream or such like is not possible under the definition. If the material is soluble in oil, water, solvents, blood, mucous or any other bodily fluid in general, it cannot be a nano-material. Full stop. (I am not going to go into the definition of soluble, I will be here all week, but there are a number of them about, you will just have to trust me).
Also if it exists naturally, ie. It is not “intentionally manufactured” it is also not a nano-material. But this is a bit trickier to work out. However it can still be done. Titanium dioxide used as a sunscreen is intentionally made to be on the nano scale, it has to be otherwise you don’t get the same UV absorption. So it is a nano-material. It is however not entirely clear at this point in time how this is going to cover other materials though. There is certainly talk of excluding natural clays for example, but nothing conclusive yet.
The same goes for the bit about “internal” structures. This was originally added to include the primary particles of any agglomerated or aggregated material that might be nano sized and to cover composite materials. There has been an awful lot of debate as to whether or not this is actually relevant though. Using Silica as an example, this has a primary particle size of approximately 30nm. However, it never exists as a primary particle, always as agglomerates with a total particle size of 10-50 microns (or 1000-5000nm) well outside the definition. To get silica into its primary particle state you really do need to add a massive amount of energy under quite specific conditions, none of which are feasible, or even possible in normal cosmetic usage. How to make a judgement on this is still being discussed. At some length.
Composite materials are a bit different and don’t really occur much in cosmetics. It tends to be surface treated materials made to give a better UV absorbance, or in some cases created to side-step the nano regulations.
Nano materials within cosmetics are not something to be scared of. Even if it means there is a new label that says “nano” on it where previously there was nothing, it is the same material and hasn’t suddenly become something else more dangerous. It is also not something that should be used as one of the many scare tactics used by the many sites discussed here on PCT on a regular basis.
Sunscreens in particular are a very important issue. If you avoid all the chemical filters (as quite a few people do) due to sensitisation or allergies, then you really only have the choice of staying permanently out of the sun or using a physical filter, which will be a nano particulate (or clothing). Most of the technology being used has been used for a very long time and has a lot of data behind it. I will admit some of it not positive, and there is still more to be done. But as the prevention of skin cancers is increasing in importance, so is the development of ever more efficient UV filters, which most importantly, are safe, but that is a different topic entirely.
Marketing companies selling products need to sound modern and scientific, and consequently use ridiculous made up terminology “contains super nano lipo actispheres”, or such like, just to differentiate their products. The claims are much more present than actual nano-materials.
Nano-technology on the other hand is worth looking at slightly differently. The most commonly used piece of nano-technology are in emulsions. A nano-emulsion is merely a very fine ( and therefore good ) emulsion. That is it. It doesn’t have any massively new, dangerous or space age ingredients. They are made by mixing oils and water with good emulsifiers. There is actually limited evidence that they are even any better than a normal non nano emulsions at delivering actives (at the end of the day the active molecules are the same size whether in a big oil droplet or a small one).
When used in articles and stories nano-technology as a general description is used in very emotive ways, mostly negative. The simple truth is that within cosmetics it is very, very limited and will certainly never turn out to be the self replicating sentient grey goo that seems to be mentioned whenever nano seems to be used in the same sentence as science !!
I will finish with a small disclaimer, the above are opinions and personal (and I think well informed ) interpretations and not an official interpretation of the legislation. This will be forthcoming from COLIPA shortly, I have seen drafts already, but as mentioned there is still a bit of discussion going on. (For those that don’t know them, COLIPA are the European cosmetics industry trade body).