What is Fullerene?

Q) What is 'fullerene'?
A) Fullerene is not just one chemical it is the name given to a class of carbon allotropes- a molecule that is made up of only one type of element. Each fullerene has a different shape, reactivity, size and solubility which in turn impacts on its safety and suitability for use in a cosmetic product. Fullerene's key characteristics are that they are 100% carbon (although they can be chemically altered making them fullerene molecules) and they have a cage like structure. The most famous example of a fullerene is the buckyball (or Buckminster fullerene) - which is 60 carbons (C60) presented in a ball-shaped arrangement. The team of scientists who 'discovered' it won a Nobel Prize in 1996.

Q) They look pretty big, are Fullerenes nanoparticles?
A) Fullerenes are manufactured nanoparticles and are way under the 100nm needed to meet the current cosmetic definition. In fact they are under 10nm individually if you can get them to stay separated! Like many nanoparticles fullerenes like to form aggregates due to particle-particle attractions so the fullerene in your skin cream is unlikely to be that small. They have the potential to act as delivery systems for highly potent actives plus they act as chemical sponges that can mop up free-radicals very efficiently.

Q) Are they natural?
A) Fullerene compounds do exist in nature but the grade used in cosmetics is manufactured synthetically by generating a large electrical current between two graphite electrodes in an inert atmosphere. This yields a mix of fullerenes which are then purified until the structure that you are after is isolated.

Q) OK, so what does the fullerene that these cosmetic people are talking about look like?
A) It is a hexagonal shaped hollow cages produced by a Mitsubishi company - Vitamin C60 in Japan. Fullerene C60 is not that easy to use as it stands as it is neither water or oil soluble until it is modified so the team at Vitamin C60 set about producing three versions of the C60 to make formulating easier. First is an oil soluble variety that is blended with vegetable squalane, the second compound is wrapped in polyvinyl pyrrolidone (the same stuff that you get in some hair gels and tablet coatings) for water dispersability and third is an ultra pure bio version that has had the harsh solvents stripped out leaving an ultra pure delivery system for pharmaceutical applications.

Q) So what do they do when they get into a product?
A) C60 fullerenes have been widely studied for their anti-oxidant potential and have proved to be highly effective at scavenging the cell-damaging free-radicals from biological systems. In addition, the hollow structure and small size make for a potential delivery system or vehicle that can help to drive other actives such as retinol, vitamin c and peptides deeper into the skin
You can see why people are getting excited!

Q) But are they safe?
A) As fullerenes are synthetic nanoparticles they are relatively new to cosmetics therefore people are worried that we don't have enough information to make a call one way or another.
Nanoparticles as a whole do warrant being treated as a separate chemical 'group' because their ultra-small size CAN make them more reactive. In addition to that there is the worry that they can get further into living tissue because they are so tiny. On top of that are concerns over how ecosystems will handle any nanomaterial that ends up in it - the particles may be fine for us to put onto our skin but may kill off the micro flora and fauna in waterways or soils. On the other hand they may do nothing of the sort and may break down very quickly due to their large surface area to volume ratio.
Laboratory and clinical trials have come up with mixed results as to the safety of fullerenes. Some have shown C60 fullerene to be almost chemically inert while others show cellular damage and toxicity in animal, confusing indeed. However, what looks on the surface to be a situation worthy of the 'precautionary principal' of formulating (don't use it if there is any doubt to its safety) the situation is much more complex in reality as the protocols behind each set of results were so different - different C60 presentation, delivery site, concentration, application method, time frame and sample size. In order to compare and contrast findings and assess the risk as when making laws it is important to understand the evidence that is presented. So far the balance shows that fullerene C60 is unlikely to be a direct health hazard when applied dermally which is why it has made its way into a number of cosmetic lines.

Q) So what's next?
Although I find the potential of these magic bullets exciting I think that they are a little too expensive for me right now. In addition, I would like to see a wider consensus from the scientific community with regards to life-cycle analysis before I jumped onto the fullerene nano-wagon.

Fascinating stuff!

Amanda Foxon-Hill

29 Sep 2010