Biophotonics: Light to cure disease

December 24, 2015

In his light-related research, Quidant is "developing a chip that could operate as a miniature laboratory in and of itself." This device would be used to identify the "signature", that is, the differentiating marker of a cancer while it is still in an initial stage of development. This research project is supported by the European Commission and is being carried out in collaboration with oncologists. How does it work? The researcher explains: "The idea is to use the latest advances in nano-optics to detect very small quantities of cancer markers in a patient's single drop of blood. Not only biophotonics are involved; we introduce a nanotechnology component as well." Quidant uses gold nanoparticles, "very small objects measuring some 50 nanometers that can be designed to act as an efficient light nanosource." His group has managed to concentrate light on a point ten times smaller than allowed by "the most perfect" of lenses. It has demonstrated that the control of light on a nanometric scale can be applied in ultrasensitive nanobiosensors and optical tweezers capable of manipulating very small biological systems without harming them.

Another line of Quidant's research relates to the heat these particles generate. In this case, the heat properties are used in cancer therapy. "The aim is to specifically affix the particles to the cancerous cells and not to the healthy ones. The particles can detect the cancerous cells thanks to recognition molecules. Once the particles have been introduced, a laser is applied to heat them until the cancerous cells are selectively destroyed," explains Quidant. Does the human body eliminate these particles? "The advantage of light is that it is less invasive than chemotherapy and radiotherapy, which also affect healthy tissue," he says. "First we need to understand how an isolated cell works before we can work on a tumor."

The research being done by Turgut Durduran and Romain Quidant enjoys the support of the CELLEX foundation in Barcelona.


Turgut Durduran, a scientist from Cyprus and the US who now lives in Castelldefels, Catalonia, has been working in this field for years. "What happens if you put your hand against a windowpane on a sunny day? The light appears to be white and your hand, red. This is the principle of the field in which I'm working: light through tissue", he explains.

One of his projects focuses on non-invasive monitoring of the blood flow and blood oxygen levels in real time using diffuse optics. "Using light, I can provide an instant view of what is happening in a patient's brain at any given moment to lend medical professionals more information on which to base their decisions. Cerebral thromboses cost millions of euros a year, and this would help the patients and lower the expenses", asserted the professor. "I basically work with hospitals. My research focuses on various projects, one of which is a monitor prototype for cerebral ischemia. We also work on issues relating to cancer, such as ascertaining whether chemotherapy is working in specific patients".

Source Institute of Photonic Sciences (ICFO)