Abián B. Socorro, in front of the prize-winning poster, in the sensors’ laboratory of the UPNA

Abián Bentor Socorro Leránoz, telecommunications engineer and research trainee at the Public University of Navarre (UPNA) has presented research work into the development of optic fibre biosensors with medical applications at the International “Trends in Nanotechnology 2012” Congress, held in Madrid. The organising committee at the Congress awarded the poster presented.

“In this poster”, he explained, “we present an optic fibre biosensor. We are working on the development of this type of biosensor for medical ends and with a novel and competitive technology, because it enables using a diversity of materials and has cheaper costs”. This telecommunications engineer, who has also done a Masters in Biomedical Engineering at the UPNA, is carrying out his PhD, as a research trainee, at the Sensors Laboratory belonging to the Optical Communications and Electronic Applications research team. Also participating in this prize-winning work were UPNA researchers Jesús M. Corres, Ignacio Del Villar, Francisco J. Arregui and Ignacio R. Matías.

A biosensor is an instrument that uses bio-receptors (in this case, antibodies) to detect biological substances of interest. In this work by Mr Socorro the detection of antigens is sought. An antigen is a substance that is foreign to the body and which the immunological system recognises as a threat and to which the system reacts by secreting antibodies. So that the biosensor is effective, the first thing to be done is to functionalise the optic fibre substrate, “To this end we use materials deposited at a nanometric scale and which have a twin role: they do not damage the biological substances with which we are working and they generate the phenomenon which we are interested in measuring”. This phenomenon is a kind of light absorption at certain wavelengths, known as lossy mode resonance (LMR). “Once the antibodies are fixed to the fibre and, as they are detected, the resonance produced in the light propagated through the optic fibre varies in wavelength. This variation we can measure and, in this case, determine the amount of antigens present”.

In principle, the more antigens detected in the sample, the more advanced the disease. “We see that if you are at an initial or final stage, you will have few antigens and few antibodies, and the resonance will move towards wavelengths close to the reference one. If the stage is more advanced, the concentrations detected will be higher, with which the resonance will change in wavelength very much”, he pointed out.

Novel devices

Today there are devices which undertake this kind of measurement, based on a similar technique. They are highly efficient but also very costly, given the equipment and the materials usually used - noble metals, principally gold. “We are seeking an alternative: using simpler machinery and being able to employ other substances such as polymers, metal oxides, etc., materials which are much less costly. This type of sensor with which we are now working is aimed at medical applications, but it can be used for many things: detecting temperature, humidity, gases, etc. Depending on what we deposit on the substrate, we generate the corresponding resonance and we can create suitable conditions in order to monitor its behaviour depending on what we wish to measure. In fact, there are colleagues currently working on this”.

* Elhuyar translation, published in www.basqueresearch.com