In recent years, biosensors have been contemplated as analytical alternatives to conventional methods in different fields. A biosensor is an analysis device made up of two fundamental elements: a bioreceptor (an antibody, a DNA probe, or a cell . . . ) prepared to specifically detect a substance, taking advantage of the specificity of biomolecular interactions, and a transducer or sensor, capable of interpreting the biological recognition reaction produced by the receptor and “transducing it” into a quantifiable optical or electrical signal. The most outstanding features of these devices which make them highly attractive options as analytical tools are their specificity, high sensitivity, response capacity leading to a short analysis time, their capacity of being included in integrated systems, ease of automation, capacity of working in real time, their versatility and low cost.
Progress in the field of biosensors lies in the experience acquired throughout the years concerning the recognition capacity and properties of various biomolecules. Many biological instruments ranging from the simplest ones such as enzymes or antibodies to more complex genetic engineering products have been used as recognition elements. On the other hand, the recent advances in microelectronics, nanotechnology and the unique properties of specific materials have been key for such devices.
Despite the foregoing, the current sensing methods are not always capable of meeting the requirements for reliability and speed. The time necessary to perform the assay and the sensitivity of the technique are some of the most significant limitations. Although the development of these devices has mainly been focused on the field of clinical diagnosis, their interest in other fields of application including the environmental, agro-food, chemical, pharmaceutical and military fields is on the rise today.
The present invention proposes a new biosensor based on the light to heat conversion properties of metal nanoparticles.