If you’ve ever had your blood drawn at regular check-ups, you may have wondered why there isn’t a simple and less painful method. While all current methods to check your vitals require invasive blood extraction, newer non-invasive technologies are hitting the market. And effortless and comfortable ways to measure the vitals are closer to reality.
Researchers at Caltech’s Cherng Department of Medical Engineering recently developed a new wearable sweat sensor that continuously detects a wide range of nutrients and molecules from your sweat and gives real-time analysis non-invasively.
Let’s know more about this research in detail.
Monitoring drugs, hormones and nutrients using Sweat Sensor
Researchers at Caltech’s Cherng Department of Medical Engineering have added a new spectrum to non-invasively analysing health using sweat sensors. The new sweat sensor can continuously monitor a larger number of target molecules, such as trace levels of various metabolites, nutrients, amino acids, vitamins, hormone levels and drugs that remain undetectable by current wearable technologies.
The ‘Nutritrek’ biosensor is designed with laser-engraved graphene (LEG) electrodes imprinted with a molecularly imprinted polymer (MIP) that can be repeatedly regenerated in situ. The sensor was developed in the Wei Gao lab, which has been working on wearable technology for many years.
This freshly formed sensor has the potential to revolutionise the market for wearable technology by powering everything from personal medical sensors to personal electronics.
How does the Nutritrek biosensor work?
The Nutritrek biosensor uses polymers that are designed to function as artificial reusable antibodies. The imprinting process provides a molecule-specific shape for sensing. For example, to detect the amino acid glutamine, the polymer is prepared with the glutamine molecules inside. Then, through a chemical process, the glutamine is removed, leaving a polymer with holes that are the exact shape of the molecule.
When in contact with human sweat, the polymer is combined with a material that can be oxidised or reduced when an electrical voltage is applied. The glutamine molecules can interact with the polymer and fit into the holes. Therefore, as the sweat increases, the electrical signal weakens.
The sensor then uses microfluidics to absorb tiny volumes of fluid. This allows the sensor to detect target molecules in sweat even when the available fluid is minimal. The researchers can then determine how much glutamine is present in the sweat by observing the electrical signal. A higher glutamine level indicates a weaker signal. A lower glutamine level leads to a stronger signal.
To monitor the data in real time, the system includes a wearable electronic patch with a wireless link to a smartwatch that can induce sweat via iontophoresis and monitor sweat via electrochemical methods. The sweat induction and the sweat sensing procedures are initiated and controlled by the microcontroller, an STM32L432KC from STMicroelectronics, when it receives a user command from the Bluetooth module over a UART link.
“This unique strategy allows us to detect all of the nine essential amino acids and multiple vitamins. We can do them all continuously.”
– Wei Gao, lead researcher.
What makes Nutritrek sweat sensors different?
- Made with molecularly imprinted polymer (MIP)
Existing sweat sensors rely on enzymes and antibodies. While they are good options, they have many drawbacks.
- Can detect a limited number of relevant compounds.
- Antibodies in the sensor can only be used once.
- Wears out quickly.
The new sweat sensor uses MIP, which allows it to detect a large number of targeted molecules. Therefore, it is reusable and doesn’t wear out quickly.
- Easy to clean
In contrast to antibody-based sweat sensors, MIP-based sweat sensors can be easily cleaned for reuse by applying a modest electric signal that destroys the target molecule or empties the hole it was in.
- Can work on less sweat
Previous sensors required more sweat and hence more current, making the user uneasy. To avoid such circumstances, the newly created sweat sensor uses Microfluidics. It allows the sensor to function with a minute amount of sweat. It uses very small currents and can induce four to five hours of sweating after only a few minutes of stimulation with tens of microamps.
Nutritrek-powered devices might be the future
The pandemic has increased health awareness around the globe, resulting in a significant rise in demand for wearable sensors. However, diagnostic devices are bulky and uncomfortable, lacking non-invasive ways of treatments and requiring constant charging. However, the Nutritrek sweat sensor allows sleek design and user comfort.
With real-time continuous monitoring, this sensor can also prove invaluable for people with chronic conditions such as diabetes, cardiovascular and kidney issues, etc.
However, the Nutritrek sweat sensor is still ongoing research and has been tested only in laboratory settings. We can only wait to see what innovation it brings to the healthcare industry.
What do you think? Let us know in the comments.
