Sunday, 22 July 2012

Lecture : Nanotechnology in Healthcare

The first in a new series of the University of Nottingham’s “ Science Public Lecture Series” featured a talk by Clive Roberts, Professor of Pharmaceutical Nanotechnology at the UoN. The talk was titled “Seeing the Nanoworld: New solutions for Healthcare” and explored the topic of nanotechnology and how it can be applied to create novel drugs and treatments. Prof Roberts began by giving an overview of some of the local high-tech companies and University departments that were involved in this area of research and development.

Molecular profiles, recent recipient of a number of awards including a Queens Award for Enterprise.

Eminate, a Nanotechnology centre in the City of Nottingham focussed on the manufacture of pharmaceutical nanomaterials.

NNNC (Nottingham Nanotechnology and Nanoscience Centre) This new centre is an equal collaboration between the Schools of Pharmacy, Chemistry, Physics and Materials.

LBSA (Laboratory of Bioscience and Surface Analysis). LBSA has an internationally reputation in scanning probe microscopy and surface chemical analysis.

Nanotechnology is very much a multi-disciplinary area, as can be seen by the fact that the team at NNNC comprise a mix of materials scientists, chemists and physicists. Prof Roberts explained that nanotechnology was interested in structures in the range 1-100 nanometre range. To give some perspective, the DNA helix is about 2nm in thickness, while the smallest cellular life is around 200nm in size. One way the nanotechnology is more than just small versions for conventional structures and machines is that, according to Prof Roberts “at that scale, new physics, new phenomena, happen”

Whilst the name “nano-technology” is only a few decades old, mankind has been using nanostructured materials, without knowing why they worked, for millennia. For example:

9th Century Abbasid ceramics had a beautiful lustre, which was caused by the use of metallic compounds that formed nanoparticles during the glazing process

B&Q have yet to replicate the lustre of these ceramics on the 9th century Mosque of Kairouan, Tunisia

Muslim Swords of the 10th century Damascus blades contained carbon nanotubes The steel of Damascus blades, used by Arab soldiers in the Crusades, had a characteristic wavy banding pattern known as damask, and an extraordinary combination of sharpness, toughness and strength. Recent research has shown that these properties were the result of the use of a particular Indian iron called Wootz, which contained a large amount of carbon and also, critically, small amounts of other metals that promoted the formation of carbon nanotubes and then a form of iron nanowire.

Characteristics wavy pattern of Damascus steel - beautiful but deadly. A bit like a Porsce 911.

The Roman Lycergus cup is a beautiful, incredibly intricate vessel that has a different colour depending on whether it is lit from the front or the back. The effect is achieved adding tiny amounts of gold and silver dust (made by colloidal precipitation) to the glass. The particles are only about 70 nanometers across, and embedded in the glass.

The Lycergus Cup - that is some serious carving going on there.
Not sure I could have handled the pressure.

Nano People
Some of the key names in the recent history of nanotechnology are Norio Taniguchi, Richard Feymann and Eric Drexler, all of whom are covered in this rather excellent Wikipeida article .

Natures Nano
The natural world is pretty much chock full of nanostructured materials and Prof Roberts provided a few of the more spectacular examples :

The nanosized hairs on a Gecko’s feet enable it to be in actual contact with a much larger proportion of the surface it is walking on than would be the case if its feet has a flat surface. It is often the case that two surfaces in intimate contact will generate a small adhesive force between themselves- the trick is to ensure that the surfaces are really in close contact. And the many tiny hairs allow the gecko to do exactly that. Perhaps unsurprisingly, there has been great interest in the possibility of a synthetic version of this natural adhesive, which has resulted in “Gecko Tape” and a experimental "Stickybot"

Gecko feet - very, very, clever. Puts Nike in their place.

Off topic, but this is a Oligocene-era Gecko trapped in amber. How cool is that?

The Lotus leaf is an extremely hydrophobic structure, and water that is placed on it stays as discrete sroplets and does not wet the surface. Although the effect has long been known, it was only with the advent of electron microscopy that scientists were able to discover that the phenomena was caused by a combmination of micron sized lumps, each covered with nanosize wax crystals, on the leaf surface. Together, these features prevent water droplets from wetting the leaf surface (you can see some cracking images here. Again, there have been attempts to make synthetic equivalents, especially for fabrics, as you can see here.

Water on Lotus leaves
Artists impression of microstructure of a Lotus leaf

The whip like flagella that some bacteria use to move around have a very mechanical looking nano-sized structure, complete with “bearings” and “stators”. It really is a quite incredible mechanism. Given the potential applications for such a generator in the portable electronics field, it is no surprise that the first tentative steps towards an artificial equivalents have been taken. It’s also worth mentioning that at the micron scale research has developed the capability of making intricate gears and other mechanisms, such as that done at Sandia National Laboratories.

Schematic of a bacterial flagella, from the relevant Haynes manual

Mite next to some MEMS micro machines. Crikey

Seeing Nano
Prof Roberts also described how the Atomic Force Probe Microscope was a key enabling technology in the nano field as it allowed researchers to observe and manipulate object on a nanoscale. The Prof provided a startling metaphor for its sensitivity by explaining that, if the tip of the microscope was the size of one of the great pyramids of Giza - a protein would be the size of a football - and yet proteins can actually be images by this technique!

How an Atomic Force Microscope Works.
Imaging atoms? Who'd have thunk it possible?

AFM tip

Image of single, rather undisciplined looking,  polymer chains.

Nano medicine
Nanotechnology has huge potential in the medical field. Applications include:

“Lab on a chip” - where chemical or biological tests are performed on samples at an extremely small scale.

Implantable sensors - where small devices are placed in the body and are able to report back on specific biological properties.

Drug Packaging - Many natural barriers to delivery of drugs are porous to nano particles. Interestingly, the window of sizes that can pass through the barrier varies, being 8-12nm for kidneys, 10-24nm in the air-blood barrier in the lungs. This can be used to advantage by creating custom-sized particles that combine the drug and a coating of nano-material. Carefully controlling the size of the final particle allows it to be targeted at a specific organ, potentially preventing harmful effects elsewhere. An example of this is Doxil, which encapsulates the drug doxorubicin in liposomes (tiny spheres of fat like molecules) about ~ 100 nm in size - which is the ideal size for the structure to penetrate tumours and also reduces harmful effects on other tissues.

Pregnancy Tests - one of the first big medical markets for nanomaterials was the use of gold nanoparticles in pregnancy (and other) tests. The principle can be seen here.

Drugs Development
Prof Roberts gave an outline of the process of drug development, pointing out that it typically costs $1billion and 12 years to develop a new drug, with only 1 in 5000 drugs getting to market and only 1 in 5 of those making any money.

One stumbling blog with otherwise promising drugs is solubility, some 40% of drugs fail because they have poor solubility characteristics.

But solubility is very much scale dependent. A grain of sand will take 34 billion years to dissolve in water. But the same grain will dissolve in one second if it is in the form of 1nanometre nanoparticles!

This scale dependency has been utilised in drugs that combine a very fine dispersed active ingredient in a polymer that has good solubility characteristics. The fine nature of the active ingredient allows it to dissolve into the surrounding body fluid in a timely manner.

Making a box from DNA
Fascinatingly, there is now research underway looking at how fragments of DNA itself can be used as a structural material. Already nano-sized boxes with hinged lids have been manufactured.

Survey of attitudes to nano materials
Lastly, Prof Roberts outlined some of the concerns regarding nanomaterials.

He described how the body has trouble dealing with very long needle-like particles such as carbon nano-tubes and also that incineration discarded nano-containing products could release the nano-particles back into the environement.

Closing the talk, he recalled a survey of ordinary people on nano-technology related issues. Whilst there had been concerns in a number of areas, when the group were asked about nano materials in cosmetics, half (the female half) were suddenly very positive, essentially saying “what ever you can do - go for it” !

Rating on the NSB Science Accessability Criteria.
The talk has provoked NSB into setting up a list of actions that it would like to see presenting organisations follow, items that make it easy to follow up on a talk and find out more information. So here goes :

1) Does the organisation have a central list of all events? No
2) It is clear, before the talk starts , whether the slides will be available on the Internet or by email?No
3) Are links provided for people to find out more information?Some
4) Are papers that are referred easily accessible, in full, to the public?No checked

Image Sources
Mihrab, Brooches, Gecko, Gecko in Amber, Lotus, MEMS Courtesy of Sandia National Laboratories, SUMMiT™ Technologies,, AFM, AFM Polymer, Flagella

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