Imaging mass spectrometry has been used by scientists for the first time to analyse diseased human tissue.

Alain Brunelle from the Institute of Chemistry of Natural Substances, in Gif-sur-Yvette, France, and colleagues from France and Spain have used a technique called cluster time of flight secondary ion mass spectrometry (cluster-TOF-SIMS) to study the lipid content of abnormal arterial tissue.

Lipids, such as fatty acids and cholesterol, are known to play an important role in the origin and progression of arterial diseases. These include atherosclerosis, more commonly known as hardening of the arteries, which can eventually lead to heart attacks or strokes.

Brunelle and his team used an ion beam to bombard the surface of frozen diseased human-artery tissue with ionic bismuth clusters. The beam causes the tissue to emit fragment ions, which are then detected to reveal precise maps of the lipid distribution. The team achieved spatial resolutions down to micrometres, far superior to other mass spectroscopic techniques. Mixtures of several lipids are seen which cannot be observed simultaneously with any other method, said Brunelle.

As Brunelle explained, the cluster imaging technique could have serious potential for diagnosing suspected lipid disorders and detection of lipids that may indicate disease. 'The ability to map several molecules without any prior knowledge opens many new applications in various fields such as biology, medicine, but also microbiology or even archaeology,' he said.

Nicholas Winograd from Penn State University, US, an expert in SIMS imaging, agreed: 'This forefront clinical pathology demonstration portends a new direction for medical diagnostics.' 

Brunelle warned that these were still early days for the technique - surface damage limits the analysis to tissue depths of less than 10nm. True 3-D chemical imaging remains a challenge in real biological samples, he said.

Stephen Wilkes