3D imaging: nanotechnology and the quest for better medical sensors

The Lunch Hour Lectures at UCL serve to provide a thought-provoking presentation to eat your lunch to (surprisingly), and last week’s Thursday instalment was no exception. Professor Ian Robinson from the London Centre for Nanotechnology, a joint venture between UCL and Imperial, walked us through the study of nano-materials using X-ray diffraction, and how such technologies can help us develop better medical devices.

The resolution of a given form of microscopy is dictated by the wavelength of the radiation exploited. In simpler terms, you can only measure the size of something with an appropriately sized ruler. X-ray crystallography is the technique by which we can probe the structure of molecules on an atomic scale. This is the technique that allows us to deduce structures from the simplest chemical compounds to the mysteries of the DNA double helix.

Robinson was keen to fill his crowd in on the history of crystallography and X-ray diffraction, as well he should be considering what influential fields they have been for the last century. Indeed, these sciences are almost exactly 100 years old, as Max von Laue demonstrated X-ray diffraction in crystals in 1912. A year later the father and son Bragg duo (William Henry and William Lawrence) described their eponymous Law, showing that the position and structure of atoms within a crystal could be inferred from their diffraction patterns.

The following two years saw Nobel Prizes for both von Laue and the Braggs, whose combined work has furthered science immeasurably, and in whose honour 2014 has been labelled the International Year of Crystallography.

We learnt about how Robinson, and other chemists, physicists and biologists from all over the globe, come to the UK to make use of the Diamond Light Source, Britain’s national synchrotron, the brightest source of light in the country.

By accelerating electrons around the synchrotron at near the speed of light, one can use magnets to abruptly change their direction, which causes them to release a high-intensity burst of X-ray radiation in a known direction. Crystallographers can then put their crystallised samples in the path of that beam, measure how the atoms within it cause the X-rays to bend, and then calculate the location of those atoms in the sample.

Finally we saw how these techniques can be applied to the development of medical sensors built on a nano-scale. The example discussed was that of glucose-sensing nano-cantilevers made from gold nanocrystals – a change in blood sugar levels could cause gold filaments to distort, transmit an electrical impulse and provide a continual, unobtrusive monitor for diabetics. X-ray crystallography provides us with a way to see what we’re doing on this scale, allowing us the chance to develop such new technologies.

James Heather is a PhD student in UCL Division of Infection and Immunity.

Image: Nobel Prize winners William Lawrence and William Henry Bragg (Source: Wikimedia Commons)

Watch the lecture below: