
A team of engineers from the California Institute of Technology (Caltech) has developed a new method to mass-produce durable wearable sweat sensors.
Using an advanced inkjet printing technique, the researchers created arrays of specialised nanoparticles that enable scalable manufacturing of biosensors.
The sensors could be used to monitor different biomarkers, such as vitamins, hormones, metabolites, and medications, in real time.
Also, providing patients and their physicians with the ability to continually follow changes in the levels of those molecules.
The scientists successfully used wearable biosensors that incorporate the new nanoparticles to monitor metabolites in patients suffering from long COVID.
Also, the nanoparticles are also used to monitor the levels of chemotherapy drugs in cancer patients at City of Hope in Duarte, California.
Caltech’s Andrew and Peggy Cherng Department of Medical Engineering professor of medical engineering Wei Gao authored a paper describing the new technique.
Wei Gao said: “These are just two examples of what is possible. There are many chronic conditions and their biomarkers that these sensors now give us the possibility to monitor continuously and noninvasively.”
According to Gao and his team, the nanoparticles as core-shell cubic nanoparticles, formed in a solution that comprises molecules that the researchers are planning to track.
In their study, the researchers combined the polymers specially formed with a nanoparticle core made of nickel hexacyanoferrate (NiHCF).
The polymers can be oxidised or reduced under an applied electrical voltage when in contact with human sweat or other bodily fluids.
The nanoparticles are versatile and are used in printing sensor arrays that measure levels of multiple amino acids, metabolites, hormones, or drugs in sweat or bodily fluids.
The researchers printed out nanoparticle-based wearable sensors specific to three different drugs on individual sensors that were later tested on cancer patients at City of Hope.
In the paper, the team also showed that the nanoparticles can be used to print sensors that can be implanted just below the skin to accurately monitor drug levels in the patient’s body.
Gao added: “This core is critical. The nickel hexacyanoferrate core is highly stable, even in biological fluids, making these sensors ideal for long-term measurement.
“Demonstrating the potential of this technology, we were able to remotely monitor the amount of cancer drugs in the body at any given time. This is pointing the way to the goal of dose personalisation not only for cancer but for many other conditions as well.”