Science fiction is about to become science fact with clothes that can provide information about the state of an injury or that can detect the emotional state of the wearer. The researcher Francisco Andrade is leading a research project to add a new function to textile fibres by enabling them to detect chemical substances. The clothing is impregnated with a carbon nanotube ink which turns the fabric into an electrical conductor. In this way, the textile can detect different chemical substances present in bodily fluids (such as sweat or urine) and transform them into electrical signals that are sensitive enough to be monitored. This allows the textiles to provide, for example, data about our physical state which can be analyzed instantly by a doctor or by the wearer using a computer or a mobile device. Francisco Andrade is part of the Chemometrics, Qualimetrics and Nanonsensors group of the Universitat Rovira i Virgili.
The general aim of the research is to modify a conventional fabric so that it can detect the chemical substances generated by the body. This is not an idea from the distant future; it is about to become reality because successful developments by the research group mean that in a few years, no more than three or four, shoppers will be able to buy interactive clothes that act as chemical sensors and that provide information about the state of their health at any given moment. This research line is led by Francisco Andrade is one several being conducted at the URV’s Chemometrics, Qualimetrics and Nanonsensors group.
“We have created a way of modifying a conventional fabric so that it functions as a chemical sensor; when it comes into contact with specific substance, an electric signal is generated that is transmitted to a measuring instrument. Metaphorically, we might say that the fabric starts to behave like a neurone” Andrade explains. The method is “quick, simple and cheap”. A conventional cotton fabric, for example, is submerged in a carbon nanotube ink and is thus turned into an electrical conductor. Then, a PVC coating is added along with other minor components and the cotton fibre has become a chemical sensor: “We have shown that the fabric can quickly and easily detect the pH and many different types of ion in bodily fluids”. In this way, the clothing can measure different chemical substances on the skin and turn them into electrical signals that are strong enough to be monitored. The fabrics will provide data about the wearer’s health that can be instantly analyzed by doctors.
The clothing can detect bodily properties without the wearer even being aware of it. “The system is completely non-invasive”, explains Andrade. To date, the sensors have been tested in clothing worn by a mannequin and were found to be able to determine the exact composition of artificial sweat. The tests are carried out using strip sensors; the mannequin’s T-shirt is soaked in a solution containing all the necessary components to see how the sensor reacts. This information is transmitted to a computer for analysis. Andrade explains that these fabrics could be very useful for measuring the formation of scar tissue in a wound or for diagnosing illnesses such as diabetes or cystic fibrosis. In the case of cystic fibrosis, by determining the concentration of chloride in the sweat a “smart” fabric would be able to detect the illness immediately, and not just when it has reached an advanced stage, as is often the case.
The composition of sports players’ sweat has been shown to be related to their metabolic state, but “measuring this outside the laboratory has, until now, been practically impossible”. However, this is not the case with the fabrics developed at the URV. For example, a cyclist who is training to achieve a certain goal may want to know how quickly his body is losing electrolytes or proteins. At any given moment, smart clothing would be able to tell him how much water he needs to drink to rehydrate himself or whether he is burning too many proteins. “He could have a smart T-shirt that warns him when he is moving from the aerobic state to the anaerobic state” the researcher stated.
The research group also developed creatinine sensors for use in “smart” nappies that can measure the components of urine, and thrombin sensors for detecting blood and other biomolecules. All of the sensors use commercially produced substrates such as paper, cotton or elastic. As such, the methodology enables conventional objects to be turned into chemical sensors, thus making them cheaper: “in the not-too-distant future, it will be possible to carry out blood or urine analyses for virtually no cost at all.”
Fabrics are already on the market that contain simple sensors for detecting energy-related properties such as vibrations, temperature, conductivity, etc. Chemical sensors are much more complex than these basic sensors because they need to be more accurate, require calibrating etc. The research group has developed tests to demonstrate that their product works: “If we target the right group of users, these fabrics could be on the market in three or four years” Andrade says. The group is in contact with a technology-based company in Cambridge that develops measuring instruments which could be used in conjunction with these sensors. They are also working with electronic engineers from NT sensors, a technology-based company of the URV that develops measuring instruments for transferring information from computers or mobile devices.
The benefits would not only be limited to field of medicine. The chemical information generated by the fabrics could also be used to detect the emotional state of the wearer. This could be useful in stressful situations such as when an investor has to take important decisions or when a driver is tired or distracted.
Francisco Andrade obtained his PhD in Analytical Chemistry in Buenos Aires, before moving to Indiana University where he carried out post-doctoral research and was eventually awarded the permanent position of “Faculty member”. In 2007 the multinational company Unilever contracted him initially as a “disruptive innovation team leader”, and subsequently as a director of Open Innovation. Through the Ramon y Cajal programme and his contacts with Francesc Xavier Rius (head of the Chemometrics, Qualimetrics and Nanonsensors research group) he was able to present the FlexSens project to the EU, which, since June 2010, has allowed him to dedicate himself fully to innovation and academic research. The project aims to develop flexible sensors that can adapt to different kinds of environment; that is, it aims to transform everyday objects into entities that can function as sensors. The project contract is four years long.
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