Stress as a health hazard: Smart sensor solutions reveal the number one cause of illness

One professional challenge chases the next, the daily flood of e-mails is simply not subsiding, family and friends should not be neglected and of course the time-intensive weekly exercise program must also not be missed. Most people are very familiar with these and similar scenarios: The days are filled with a plethora of large and small professional and private obligations that must be organized, planned, and completed. Situations and challenges like these can quickly turn into stress, which may have positive as well as negative effects on the human body.

Always stressed out: The effect of permanent strain on the human body

“Basically, stress is a natural reaction of our body to certain stimuli, which cause the body to be in a state of alarm and to immediately mobilize its energy reserves. By releasing stress hormones such as adrenaline and cortisol, our brain works at full speed, our muscles become tense, breathing speeds up, the heart beats faster and our senses are heightened. This makes our body ready to perform at the highest level within a flash. Once the situation causing the stress subsides, the release of stress hormones is also throttled, the body relaxes again and comes to rest,” explained Dr. Mario Baum, head of the “Health Systems” department at Fraunhofer ENAS.

Stress is caused by a large number of internal and external stimuli, the so-called stressors that trigger such a stress reaction in the body. These stress causing factors can range from extreme noise, professional and private conflicts, overload at the work place, illnesses, via permanent pressure to perform and meet deadlines, up to worries and fears for the future. “However, stressors are very subjective and vary from one person to the next. While some stimuli cause very high stress levels in some people, others may consider these situations to be completely unproblematic and possibly even pleasant,” explained the scientist.

This shows that stress can be experienced both positively and negatively. If the mastering of tasks and challenges is perceived as enriching and motivating while being accompanied by joy and pleasurable feeling, we talk about positive stress, the so-called eustress. However, if it is accompanied by fears and an unpleasant feeling of being overwhelmed, the person experiences negative stress, the so-called distress.

“Negative stress in particular constitutes a major health risk. A permanent strain can promote the development of psychological illnesses and physical limitations. Permanently excessive cortisol values in the blood and constant tension quickly rob the body of its last energy reserves. Initial heart palpitations, irritability and loss of appetite can in the long run turn into chronic fatigue, exhaustion, burn-out, or depression. According to physicians, a constantly elevated stress level may promote the occurrence of cardiovascular diseases such as heart attacks and strokes, or also diabetes. While there is no scientific evidence of the connection between stress and the occurrence of cancer, physicians nevertheless presume that chronically exceeding the body’s tolerance levels weakens the immune system in the long term and may lead to the formation of cancer cells,” explained Mario Baum.

Recognizing warning signs: Fraunhofer “stress sensor system” identifies permanent stress

The recognition of long-term excessive stress of the body and countering it by suitable therapeutic measures requires effective diagnostic monitoring tools. These help in the early detection of stress indicators and initial warning signs of the body before serious illnesses can develop.

The researchers at Fraunhofer ENAS are developing such a tool. A patient-friendly multi-biosensor system will in the future allow the comprehensive detection and constant monitoring of various vital parameters and biomarkers that indicate excessive stress. As a wearable, the monitoring tool is equipped with miniaturized electro-chemical sensors and can be used flexibly.

“People who feel very stressed often tend to sweat more. Sweat contains the stress hormone cortisol that can be measured via the skin. With the aid of our wearables, which users carry close to their bodies, cortisol levels can be permanently monitored. Subsequently, the collection and evaluation of physiological health parameters, such as the heart beat and breathing can not only provide an indication of permanent negative and chronic stress, but also provide a complete picture of the health status of patients. This could effectively support comprehensive diagnosis,” summarized Mario Baum.

According to the scientist, the approach is particularly interesting in the area of gender medicine. “Not only do the genders perceive stress differently, but men and women also react differently to it. While the bodies of both men and women release the stress hormone cortisol in stressful situations, the cortisol level in the blood of men increases much more than in women. In addition, in stressful situations womens bodies increasingly release the hormone progesterone, while men release testosterone, which may effect the reaction to and the handling of the stressful situation. A comprehensive diagnosis that takes the various stress parameters into account and places them into an overall health picture could lead to clearer results and ultimately to customized therapies.”

At the core of the “stress sensor”: Carbon nanotubes in biosensing detect target molecules

Central and key to the Fraunhofer “stress sensor technology” are carbon nanotubes (CNT), which are applied as versatile and powerful modules in the next generation of electronic designs. Biosensors based on these thin, semi-conducting functional nano layers are distinguished by exceptional sensitivity. This characteristic of CNT-based sensors allows the reliable and quick detection of even the smallest quantities of biological and chemical analytes, such as biomarkers. Since they enable the implementation of highly miniaturized sensors that require little space, they are ideally suited for light, portable and mobile point-of-care technologies, such as wearables for health monitoring.

“For CNT-based sensors to be able to detect the hormone molecule cortisol, we have to functionalize them. This is done with the help of capture molecules, the so-called aptamers that are immobilized on the surface of the sensor. These special DNA molecules are folded and create a ´docking station´ of sorts. Only the specific target molecules that are to be detected fit this docking station and bind to the aptamer. This ‘binding event’ is transformed into an electrical output signal with the help of a CNT-based field-effect transistor (FET). The signal is in turn measured and evaluated in real time. This way, an excessive amount of cortisol can be detected,” explained Andreas Morschhauser, deputy head of the “health systems” department, regarding the advantages of CNT-based sensors that are researched and developed at Fraunhofer ENAS.

Another characteristic of biosensors based on CNTs is their capacity of detecting the target molecules to be identified without marking. “This eliminates elaborate and costly interim steps of sample preparation to mark target molecules, for example with the help of fluorophores. As a result, detection of the target molecules can take place considerably faster than before,” added the scientist.

When integrated into microfluidic cartridges, CNT-based sensors are not only suitable for point-of-care (POC) applications for patient-side quick diagnosis, but also in the veterinary medicine sector.

Stress in the barn: Animal health hazards due to excessive stress

The perception of stress is not limited to humans only, animals also sense stress caused by various stress factors. These include social factors such as fights over the dominance hierarchy in a herd, as well as external factors such as changing the type of feed, permanent noise, or heat. “In such stress situations their bodies also release stress hormones such as cortisol, which can have detrimental physical effects such as increased infections and digestive problems, or lead to behavioral issues such as changed eating and grooming habits, aggression or flight reactions,” explained Andreas Morschhauser.

Cows, for example, react very sensitively to stress, including decreased productivity that may lower their milk output. In combination with other sensors, portable microfluidic systems with CNT-based biosensors could help farmers control the stress levels of their livestock, intervene early on, and increase the wellbeing of the animals.

Stress reactions of animals are not only problematic for the animals and their health, but also regarding their effects on humans. This is because stress, particularly in productive livestock, can also affect human wellbeing. “An excessive cortisol level in the blood occurs in animals during their slaughter. This can negatively affect the quality of the meat and affect humans. The released cortisol stress hormone is stored in the meat and ingested by consumers. This can promote problems such as infection processes in the body or a weakened immune system,” explained the Fraunhofer researcher Andreas Morschhauser.

Less stress for humans and animals: Multi-sensory systems increase the quality of life and animal health

In addition to the effective detection of stress signals in humans and animals, modern science is even going one step further: The aim is to not only identify stress in the future, but to reduce it to a minimum or prevent it altogether. The research is particularly focused on cancer patients. They should receive better care in the future with personalized and customized pain and chemotherapy that are less stressful for the body. What is more, animal testing in the research of effective cancer therapeutics should be avoided altogether.

“Stress may not only lead to physical and psychological illnesses, but in return a diagnosed life-threatening illness may also be the cause of increased stress levels. Cancer, in particular, causes great strain on the affected persons, not exclusively due to worries and fear. Medicinal therapy causes additional stress to the already weakened body as it not only affects tumor cells but healthy cells as well. At the same time, it is often not known at the beginning of the treatment whether the chemotherapy will be effective and actively combat the cancer cells,” said Mario Baum.

This is where the researchers from the German state of Saxony are bundling their strengths: In collaboration with scientists of the Fraunhofer Institute for Cell Therapy and Immunology IZI of Leipzig, the researchers of Chemnitz are working on an organ-on-chip model (OoC), based on multi-sensors that maps and simulates the structure and function of human organs in a miniature format with the help of cell cultures. Mario Baum and his team are developing highly sensitive sensors that will be at the core of the OoC model.

“The idea behind such cell-based diagnosis and medication in the area of oncology is to remove cancer cells from the patients that are then cultivated with the help of an OoC model in a microfluidic environment. By introducing cancer medication the cells are put under stress so to speak and their reaction to the therapy investigated. This way, the effectiveness of medications can be constantly observed on a cellular level in real time on an individual patient basis and thus predicted prior to the start of therapy. This way, it can be ensured that the affected persons are later on only administered medications that were found to be individually effective in the artificial model. This will considerably decrease the stress levels of patients. At the same time, animal suffering due to animal testing for medical research can be avoided,” explained the scientist.

The uses of sensor solutions by Fraunhofer ENAS for the measurement of stress on a cellular level are not only limited to personalized medication. They can also be used to better research the side effects of medication or to simulate the reaction of cells when infected with pathogens.

Smart is key: An innovative and technological partner for modern healthcare and life science applications

The smart sensors made by Fraunhofer ENAS combine sophisticated microsystems engineering with nanotechnology allowing new paths to be taken in human and veterinary diagnostics. They are also ideally suited for the food quality and safety sector as well as environmental analysis.

Ultra-sensitive multi-sensor solutions, microfluidic lab-on-chip and organ-on-chip systems along with point-of-care approaches are the result of decades of expertise in developing technologies for healthcare and life science applications at Fraunhofer ENAS. As key enablers of efficient modern diagnostics and analytics, they allow the measurement of a wide range of chemical and biochemical parameters at the utmost precision and speed, in both stationary and mobile application scenarios.

If you want to find out how Fraunhofer ENAS is creating new impulses for the health technologies of tomorrow to create a balance between human and animal wellbeing and a healthy environment, then do not hesitate to contact us today.