Lasers to Help Spot Killer Diseases Such as Cancer

New optical techniques use light to make diagnoses from a single drop of blood, or to guide surgeons during operations.

Detecting killer diseases early with relatively inexpensive optical technology can help to save lives. It can also avoid the need for more invasive and expensive treatments further down the line.

The EU-funded PHAST-ID project is developing a very low-cost, disposable diagnostic optical sensor that could have a huge impact on the detection of pancreatic cancer.

‘These tests could be carried out right at the doctor’s surgery,’ said Dr Alan O’Riordan, of the Tyndall National Institute in Cork, Ireland, who is coordinator of the PHAST-ID consortium. ‘It could be as easy to use as a glucometer (glucose meter), of the kind used every day by diabetics.’

It’s one exciting development from the emerging field of biophotonics, where light is also being used to diagnose disease, help surgeons identify tissue for removal, and in high-resolution microscopes that see into living cells to investigate cell division in cancers and the origin of diseases in general.

Each year, 70 000 people are diagnosed with pancreatic cancer in Europe. Around 95 % of people will die within five years, and that’s because standard medical technologies such as magnetic resonance imaging and ultrasound can only spot the disease at a very advanced stage.

The PHAST-ID sensor measures changes in a patient’s blood to identify the disease’s telltale chemical patterns, known as biomarkers, well before the pancreas itself shows noticeable symptoms.

The pre-prepared sensor uses antibodies to identify if the disease is present. A drop of the patient’s blood is put on the sensor and, if the disease is present, then the antigens will bind with the antibodies on the sensor, causing a shift in the spectrum of the light shone through it.

‘By measuring that shift you can determine if the antigen is there or not and how much of it is there,’ Dr O’Riordan said. ‘These biomarkers are present in the body anyway, but the concentrations are changed by the cancer – they go out of kilter. So it’s the patterns of concentration and the changes in those patterns that are really important.’

The sensor is based on a photonic crystal and is much smaller than existing technology. It uses a white light source or a basic laser like those in presentation pointers; its detector uses an inexpensive micro-camera like that in a mobile phone.

It’s much faster and easier to do than commonly used methods of diagnosis with antibodies, which usually require samples to be stained or labelled with enzymes or other chemicals and rely on highly trained people and sophisticated laboratory equipment.

The disposable sensor can be made using standard microelectronic techniques, such as nanoimprint lithography, and costs as little as EUR 3 to 5 per unit, even before the economies of scale that commercial development could bring.

The consortium aims to make the test even more sensitive by adding more of the pancreatic cancer biomarkers to those already included before the project ends in the next few months.

PHAST-ID’s approach could also be developed for other diseases where defined biomarkers have been identified, such as breast cancer or the autoimmune disease lupus.

‘It doesn’t even have to be a disease. Once there is an antibody present for a biological molecule, this platform will use it. It’s a general platform, not a sensor-specific platform for pancreatic cancer,’ Dr O’Riordan said.

Biophotonics also holds out strong promise in surgery, to control more precisely the success of medical interventions, said Professor Jürgen Popp, the coordinator of Photonics4Life, an interdisciplinary network of European researchers and practitioners developed with EU funding.

‘One idea with optical technology is that if you have to cut, for example in heart surgery, whether with a conventional scalpel or a laser scalpel, you can monitor the tissue that is in front of you so you can say: is this a blood vessel, is this a nerve, to ensure you do not destroy things that should not be destroyed,’ Prof. Popp said.

Researchers in Germany who are involved with the network are even developing ways to use fluorescence to illuminate colon tumours during surgery.

The Photonics4Life network aims to help technologists and medical professionals work more closely together in the field of photonics research.

The network has also succeeded in encouraging collaboration in local clusters of medical professionals and technical researchers involved in photonics. The aim is to involve medical experts in developing new technologies and to prioritise those most needed from a medical point of view, rather than perfecting the technology and then casting around for an application.

‘The vision behind biophotonics is that you get a holistic understanding about health and how diseases should be handled in the future,’ said Prof. Popp, who is scientific director of the Leibniz Institute of Photonic Technology, Jena, Germany.

‘The most important result is to get people from the different disciplines together. The idea is that we can encourage a move from a technologically driven approach to a holistic, user-driven approach,’ he added. -- by Rex Merrifield, for Horizon Magazine, © EU