A portable device to monitor metabolites and nutrients


Today we want to highlight an interesting development on the wearable diagnostic front: researchers have developed a wearable device that can monitor nutrients, hormones, and medications. [1].

Real-time health monitoring

The popularity of medical wearables has grown in recent years. A few decades ago, a complex diagnostic machine capable of measuring molecules circulating in the blood would have been a big, intrusive and cumbersome affair, but thanks to progress such systems can be small and portable. This is largely thanks to advances in processor technology and the ever smaller sizes in which they can be produced.

These researchers, based at Caltech’s Cherng Medical Engineering Department, recently revealed this new device. They showed how it could detect even trace amounts of nutrients and other molecules in human sweat. These nutrients and molecules can serve as useful biomarkers to determine human health in real time.

The technology behind the sensor was developed in the Wei Gao lab, which has been developing wearable technology like this for many years. This new, more precise device represents a new pinnacle of his work.

Perhaps the most interesting thing about the new sensor is that it uses molecularly imprinted polymers, which are designed to work like artificial, reusable antibodies. This specially formed polymer is combined with a material that can be oxidized or reduced when an electrical voltage is applied in contact with human sweat.

Finally, the device uses microfluidics, which uses many microscopic tubes less than a quarter of a millimeter wide to absorb tiny volumes of fluid. This allows the sensor to monitor target molecules in sweat even when the amount of fluid available is minute.

The device has been tested by human participants in the lab with positive results. Dr. Gao hopes to test the device in larger-scale human studies as the next step.


Noninvasive wearable biosensors for continuous monitoring of metabolites in sweat can detect a few analytes at high enough concentrations, typically during vigorous exercise to generate sufficient biofluid. Here we report the design and performance of a wearable electrochemical biosensor for the continuous analysis, in sweat during exercise and at rest, of traces of several metabolites and nutrients, including all essential amino acids and vitamins. The biosensor consists of graphene electrodes that can be repeatedly regenerated in situ, functionalized with metabolite-specific antibody-like molecularly imprinted polymers and redox-active reporter nanoparticles, and embedded in modules for induction iontophoresis-based sweat sampling, microfluidic sweat sampling, signal processing and calibration and wireless communication. In volunteers, the biosensor allowed the real-time monitoring of amino acid intake and their rate during physical exercise, as well as the assessment of the risk of metabolic syndrome (by correlating amino acid levels in serum and sweat). Monitoring of metabolites for early identification of abnormal health conditions could facilitate applications in precision nutrition.


Since the device can potentially measure a wide range of nutrients, metabolites, hormones and drugs, the usefulness here is obvious. Being able to monitor biological changes in real time could provide researchers with very valuable information and help inform follow-up studies.

Beyond clinical trials for aging interventions, such technology could also prove popular in the public health wearable device market. Imagine being able to monitor your nutrient intake and see how things change in real time. It could also prove invaluable for people with conditions such as diabetes, helping them to optimize their blood sugar levels.

The ability to continuously monitor health biomarkers in real time has nearly limitless applications, and it’s an exciting development in biomarker diagnostics and monitoring.


[1] Wang, M., Yang, Y., Min, J., Song, Y., Tu, J., Mukasa, D., … & Gao, W. (2022). A portable electrochemical biosensor for monitoring metabolites and nutrients. Natural biomedical engineering, 1-11.


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