With sweat, you can know a lot about health and crime

Sweating is a small affair, but the information we can collect is not small at all.

Most people want to reduce the amount of excretion. But perhaps you do not know this is considered a valuable data source to help researchers exploit to fight disease as well as apply . security technology on smartphones . Sweat is a mixture of chemicals that not only signals how our body is now, but also very special for each person, when all of us have no sweat like anyone else.

In a recent report published in Analytical Chemistry, University At Albany Jan Halámek's forensic scientist and his colleagues said they analyzed 25 samples of sweat from volunteers and 50 samples of artificial sweat (simulate a mixture of chemicals in sweat). By looking at the concentrations of the three chemical components: urea, glutamate and lactate in sweat, they find that it is very simple to distinguish whose pattern of sweat is.

Therefore Halámek wanted to apply this idea into criminal work, because sweat once flushed out would be very difficult to completely erase at the crime scene, so that it could easily find criminals from the grave itself. His foul compared to relying on fingerprints. Besides, his team is confident to declare only with a specialized material developed by them that law enforcement forces can sample the sweat and analyze it in the blink of an eye.

Rafael Nadal player at Rolex Monte-Carlo Master 2018 tournament.

This idea is not the same as using DNA to analyze and find the culprit who owns the gene, because DNA is fixed and sweat contains the changing amount of chemicals within a day, so it will be difficult to identify. Whose sweat is that? Mostly this measure is only feasible in delineating suspects, sweat marks can show how many specific people were present at the scene. Previously, Halámek had researches using sweat to find sex (even with the pattern of sweat of a few months old baby). Currently his team is working on developing a "forensic toolbox" to identify each person's specific factors such as gender, age and eating habits. Halámek said: "I hope one day I will be able to analyze the sweat at the crime scene and deduce that the suspect is" a tall, white, good health "or" a woman. " old man with "liver disease".

Although the chemical components in sweat do not help the forensic experts find out exactly which individual it is, it can be applied to unlock mobile devices instead of encryption, face detection. or even fingerprints."Fingerprints are fixed so they can be fake but sweat is always changing, so if somehow I get your sweat pattern, I won't be able to unlock the phone a few hours later. " , Halámek said.

So how does it work? If your sweat is always changing, how can you unlock your phone?The key is that the chemicals in sweat always change in a predictable way . When you have a new phone, you will touch it many times a day, so that the phone will analyze the chemicals in sweat at 2 pm and 9 pm. Over a period of time until enough data is available, the algorithm will analyze how your sweat changes, so the phone can identify you. Of course, it is still possible to bypass the phone but it will take more effort.

Simmers, a biomedical doctoral candidate at the University of Cincinnati, says scientists can cause sweating by putting a coin-sized electrode (usually made into a patch). Someone's hands combine gel stimulation and run light streams. After stimulating a spot on the skin for a few minutes, it will perspire for 24 hours. But the sweat of diluting the gel, making it difficult to reach the skin, makes it difficult to estimate the appropriate gel dosage and stimulate an exact amount of sweat. Also, when the gel and sweat get confused, the sensor gets more complicated when analyzing sweat.

To solve this problem, Simmers and his team developed a special membrane. Recently, this study has been published in Biomicrofluidics magazine. Their membranes maintain almost all the initial concentrations of the gel, even after a day - meaning the gel and sweat will not be confused. Simmers and colleagues are currently testing the use of membranes on biosensors. Those working with him include University of Cincinnati biologist Jason Heikenfeld, who established a startup called Eccrine Systems to create wearable devices that can accurately track sweat.

Similarly, NextFlex has tested sweat patches to help track hydration and stress."The patches are pretty much like a big piece of tape, there are layers and paste on human skin , " said Scott Miller, NextFlex's strategic program director. This patch absorbs sweat and sends it to an internal sensor that measures the concentration of chemicals, then analyzes and sends it to another system via a wireless connection.

According to Miller, Air Force is very interested in this patch."The Ministry of Defense has seen the benefit of monitoring the hydration process of soldiers and pilots, who are susceptible to dehydration and health effects during physical training and practice. They can help coaches or sergeants know who is tired, give them a really good rest . " It is also suitable for sports athletes.

Another feature of this patch is to measure stress , or more precisely, to monitor hormones like cortisol that are related to perspiration. Its biggest application is for pilots, airplane operators, drone operators or anyone who works in a factory.

In the past, blood was considered the gold standard for health monitoring, but testing was expensive and needed experienced people. Devices like Fitbit can measure your heart rate and alert you when it rises, but that's all but not for the reason. On the other hand, sweating is not painful but still contains different hormones, proteins and ions to detect the disease. In addition, sensors are being developed to measure blood sugar to detect people with diabetes and ethanol to know who has been drinking with many other applications."There are a lot of things being developed in this area with many different sensors, their capabilities are really great," Simmers said.