A Doctor in Your Pocket

Scientists taking part in the European project BIOTEX have developed prototype biosensors, which can be integrated into special fabrics. The sensors are capable of measuring sodium, chloride, and potassium in miniscule volumes of sweat samples on the skin. An added immunosensor can also detect the presence of specific proteins in sweat. This technology will enable a constant monitoring of our vital signs and will provide a non-stop medical assessment of our health.

BIOTEX project diagram (Credit: BIOTEX) 
BIOTEX project diagram
(Credit: BIOTEX)

It is 12 AM, and you are having the headache of your life. You can not concentrate on your screen, and you are too tired to care. All of a sudden, your phone rings. It’s your doctor, and he is worried.

“Sir,” he says, “Your tie just called me about your perspiration. You’re almost dehydrated. You really should drink a few cups of water!”

New fabrics are making their way to the market. They may not look like much at first – just your ordinary, run of the mill, cloths. However, when one looks deep into the fabric, a very different picture is revealed. All throughout the fibers, micro-chips and micro-sensors are hidden. Some of the sensors are so small that they cannot be seen with the naked eye. Their affect on our health and lifestyle, however, is going to be nothing short of revolutionary. At the moment, there are sensors that can measure the wearer’s body temperature or trace his or her heart activity. But, as the European Union’s SFIT group (Smart Fabrics, Interactive Textile) is bent on proving, sensors of this kind mark the beginning of a new era. If their predictions come true, quite soon the new fabrics will also be able to analyze the sweat our body exudes, and provide a non-stop assessment of our health.

An important recent achievement by the SFIT Group BIOTEX Project partners has been the development of prototype ionic biosensors, capable of measuring sodium, potassium, and chloride in sweat samples. Another probe developed by the scientists measures the conductivity and acidity of sweat. The BIOTEX partners – universities and small enterprises from Italy, France and Ireland – have also developed an immunosensor, which could be integrated into wound dressings or bandages and can detect the presence of specific proteins in fluid samples.

A Practical Solution to a Practical Problem

Of course, having an array of biosensors in a textile patch is one thing, but how do you get the miniscule volume of fluid secreted from sweat glands to the biosensors?

The solution developed by BIOTEX Project scientists uses a combination of hydrophilic (water-attracting) and hydrophobic (water-repellent) yarns. The different threads are woven together to direct the sweat through fabric channels to the sensor array. This method requires no power, and therefore, reduces the power demands of the entire system.

But Some Problems Remain

Plastic Optical Fibers integrated into textile by Penelope (Credit: BIOTEX) 
Plastic Optical Fibers integrated
into textile by Penelope (Credit: BIOTEX)

The most difficult problem is overcoming the sensing process. Many of the chemical and biochemical reactions used in the sample sensors are non-reversible, meaning that some part of the biosensor must be replaced every now and then, probably along with the piece of clothing. The BIOTEX team may have a hard time convincing consumers it is in their best interest to buy a new shirt every week and this also makes very little sense in terms of cost.

In the first trials, the smart patches will be integrated into clothes worn by obese people, diabetics, and athletes. Once the technology has been validated, the plan is to take on industrial backers in order to commercialize the technology and bring it to the consumer market. Even if the market is not yet ready for the non-reversibility of the sensing process, the researchers are not worried. Their smart sensors will still find an important use in a different EU-funded project, called PROTEX. In the PROTEX Project, the technology will be integrated with other micro- and nano-systems for specific government-funded applications, such as firefighting and rescue teams.

TFOT recently covered the development of self-cleaning fabrics, which can remove stains and protect themselves from UV degradation. TFOT also covered self-charging clothes, which are capable of generating power from the wearer’s movements, as well as light-emitting textiles and fabrics capable of monitoring physiological signs.

More information on the BIOTEX Project can be found on the project’s website.